Hematology (Am Soc Hematol Educ Program) . 2001;:433-42. Reducing the risk of blood transfusion; Snyder EL et al.; There are continuing concerns over the safety of the nation's and the world's blood supply . The allogeneic blood supply is tested for antibodies to HIV1/2, HTLVI/II, hepatitis B, hepatitis C (HCV) and syphilis . Testing is also performed for donor ALT (SGOT) levels, for the presence of hepatitis B surface antigen, human immunodeficiency virus (HIV) p24 antigen and, using nucleic acid amplification testing (NAT), for HIV and HCV nucleic acids . Still, there are concerns regarding other pathogenic agents . Dr . Roger Dodd addresses a series of pathogens that are already known to be transmissible by transfusion . These include malaria, Chagas' disease, babesiosis, bacteria and some viral agents . The need for new donor screening assays to protect the integrity and purity of the blood supply must be balanced against the loss of potential donors and the cost of developing and implementing these new screening assays . This issue will be highlighted . Dr . Edward Snyder reviews the status of research into development of systems for pathogen inactivation (PI) of blood and its components . A proactive technology wherein PI reagents such as psoralen, riboflavin, dimethylmethylene blue or inactine are added to blood collection bags could assure multiple log reduction of a variety of pathogens including viruses, bacteria, protozoa and fungi without the need to initially pre-screen the blood for a specific pathogen . Such a program could also cover new pathogens as they enter the blood supply . As a key issue relates to the toxicology of these agents, Dr . Snyder provides data on a novel carcinogenicity assay that uses a heterozygous p53 knock-out mouse model . The criteria likely to be needed for PI technology to be adopted by the transfusion community are summarized. Mol Microbiol, 2001 Nov, 42(3), 741 - 55 The chromosome partitioning protein, ParB, is required for cytokinesis in Caulobacter crescentus; Mohl DA et al.; In Caulobacter crescentus, the genes encoding the chromosome partitioning proteins, ParA and ParB, are essential . Depletion of ParB resulted in smooth filamentous cells in which DNA replication continued . Immunofluorescence microscopy revealed that the formation of FtsZ rings at the mid-cell, the earliest molecular event in the initiation of bacterial cell division, was blocked in cells lacking ParB . ParB binds sequences near the C . crescentus origin of replication . Cell cycle experiments show that the formation of bipolarly localized ParB foci, and presumably localization of the origin of replication to the cell poles, preceded the formation of FtsZ rings at the mid-cell by 20 min . These results suggest that one major function of ParA and ParB may be to regulate the initiation of cytokinesis in C . crescentus. Mol Microbiol, 2001 Nov, 42(3), 717 - 27 Roles of the two ClpC ATP binding sites in the regulation of competence and the stress response; Turgay K et al.; MecA targets the competence transcription factor ComK to ClpC . As a consequence, this factor is degraded by the ClpC/ClpP protease . ClpC is a member of the Clp/HSP100 family of ATPases and possesses two ATP binding sites . We have individually modified the Walker A motifs of these two sites and have also deleted a putative substrate recognition domain of ClpC at the C-terminus . The effects of these mutations were studied in vitro and in vivo . Deletion of the C-terminal domain resulted in a decreased binding affinity for MecA, a decreased ATPase activity in response to MecA addition and decreased degradative activity in vitro . In vivo, this deletion resulted in a failure to degrade ComK and in a decrease in thermal resistance for growth . Mutation of the N-terminal Walker A box (K214Q) caused a drastically decreased ATPase activity in vitro, but did not interfere with MecA binding . In vivo, this mutation had no effect on thermal resistance, but had a clpC null phenotype with respect to competence . Mutation of the C-terminal Walker A motif (K551Q) caused essentially the reverse phenotype both in vivo and in vitro . Although binding to MecA was only moderately impaired with 2 mM ATP, this mutant protein displayed no response to 0.2 mM ATP, unlike the wild-type ClpC and the K214Q mutant protein . The ATPase activity of the K551Q mutant protein, induced by the addition of MecA plus ComS, was decreased about 10-fold but was not eliminated . In vivo, the K551Q mutation showed a partial defect with respect to competence and a profound loss of thermal resistance . Sporulation was reduced drastically by the K551Q and less so by the K214Q mutation, but remained unaffected by deletion of the C-terminal domain . Although the evidence suggests that the functions of the two ATP-binding domains overlap, it appears that the N-terminal nucleotide-binding domain of ClpC is particularly concerned with MecA-related functions, whereas the C-terminal domain plays a more general role in the activities of ClpC. Mol Microbiol, 2001 Nov, 42(3), 603 - 17 Icm/dot-dependent upregulation of phagocytosis by Legionella pneumophila; Hilbi H et al.; Legionella pneumophila is the causative agent of Legionnaires' disease, a severe pneumonia . Dependent on the icm/dot loci, L . pneumophila survives and replicates in macrophages and amoebae within a specialized phagosome that does not fuse with lysosomes . Here, we report that phagocytosis of wild-type L . pneumophila is more efficient than uptake of icm/dot mutants . Compared with the wild-type strain JR32, about 10 times fewer icm/dot mutant bacteria were recovered from HL-60 macrophages in a gentamicin protection assay . The defect in phagocytosis of the mutants could be complemented by supplying the corresponding genes on a plasmid . Using fluorescence microscopy and green fluorescent protein (GFP)-expressing strains, 10-20 times fewer icm/dot mutant bacteria were found to be internalized by HL-60 cells and human monocyte-derived macrophages (HMMPhi) . Compared with icm/dot mutants, wild-type L . pneumophila infected two to three times more macrophages and yielded a population of highly infected host cells (15-70 bacteria per macrophage) that was not observed with icm/dot mutant strains . Wild-type and icmT mutant bacteria were found to adhere similarly and compete for binding to HMMPhi . In addition, wild-type L . pneumophila was also phagocytosed more efficiently by Acanthamoeba castellanii, indicating that the process is independent of adherence receptor(s) . Wild-type L . pneumophila enhanced phagocytosis of an icmT mutant strain in a synchronous co-infection, suggesting that increased phagocytosis results from (a) secreted effector(s) acting in trans. Immunol Rev, 2001 Aug, 182, 190 - 200 Control of intestinal inflammation by regulatory T cells; Singh B et al.; Transfer of CD4+ T cells to immune-deficient mice in the absence of the CD25+ subset leads to the development of colitis, indicating that regulatory cells capable of controlling a bacteria-driven inflammatory response are present in normal mice . Cells with this function are present in the thymus as well as in the periphery of germ-free mice, suggesting they may be reactive with self-antigen . These cells resemble CD4+CD25+ cells that inhibit organ-specific autoimmunity, suggesting that a similar subset of regulatory T cells may control responses to self and foreign antigens . Development of colitis is dependent on accumulation of activated CD134L+ dendritic cells (DC) in the mesenteric lymph nodes, which is inhibited by CD4+CD25+ cells, indicating that regulatory T cells may control DC activation in vivo . Whilst inhibition of T-cell activation in vitro by CD4+CD25+ cells does not involve interleukin-10 and transforming growth factor-beta, these cytokines are required for the suppression of colitis . It may be that control of responses that activate the innate immune system requires multiple mechanisms of immune suppression . Recently, we identified CD4+CD25+ cells with immune suppressive activity in the thymus and peripheral blood of humans, raising the possibility that dysfunction in this mechanism of immune regulation may be involved in the development of autoimmune and inflammatory diseases. Eur J Biochem, 2001 Nov, 268(22), 5776 - 82 The tetraheme cytochrome c NrfH is required to anchor the cytochrome c nitrite reductase (NrfA) in the membrane of Wolinella succinogenes; Simon J et al.; The electron-transport chain that catalyzes nitrite respiration with formate in Wolinella succinogenes consists of formate dehydrogenase, menaquinone and the nitrite reductase complex . The latter catalyzes nitrite reduction by menaquinol and is made up of NrfA and NrfH, two c-type cytochromes . NrfA is the catalytic subunit; its crystal structure is known . NrfH belongs to the NapC/NirT family of membrane-bound c-type cytochromes and mediates electron transport between menaquinol and NrfA . It is demonstrated here by MALDI MS that four heme groups are attached to NrfH . A Delta nrfH deletion mutant of W . succinogenes was constructed by replacing the nrfH gene with a kanamycin-resistance gene cartridge . This mutant did not form the NrfA protein, probably because of a polar effect of the mutation on nrfA expression . The nrfHAIJ gene cluster was restored by integration of an nrfH-containing plasmid into the genome of the Delta nrfH mutant . The resulting strain had wild-type properties with respect to growth by nitrite respiration and nitrite reductase activity . A mutant (stopH) that contained the nrfHAIJ locus with nrfH modified by two artificial stop codons near its 5' end produced wild-type amounts of NrfA in the absence of the NrfH protein . NrfA was located exclusively in the soluble cell fraction of the stopH mutant, indicating that NrfH acts as the membrane anchor of the NrfHA complex in wild-type bacteria . The stopH mutant did not grow by nitrite respiration and did not catalyze nitrite reduction by formate, indicating that the electron transport is strictly dependent on NrfH . The NrfH protein seems to be an unusual member of the NapC/NirT family as it forms a stable complex with its redox partner protein NrfA. Anal Chem, 2001 Nov 1, 73(21), 5150 - 6 Fiber-optic luminescent sensors with composite oxygen-sensitive layers and anti-biofouling coatings; Navarro F et al.; Anti-biofouling polymers containing phosphorylcholine (PC)-substituted methacrylate units have been prepared by copolymerization with dodecyl methacrylate and used to coat luminescent oxygen sensors . Nanometer-sized coatings of such materials are shown to reduce significantly the adhesion of marine bacteria (more than 70%) and thrombocytes (more than 90%) to the surface of tris-(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)-doped silicone layers . A thorough analytical characterization of both the PC-coated and the uncoated dyed films has demonstrated that the anti-biofouling layers do not alter dramatically the performance of the fiber-optic oxygen sensors in aqueous media and are mechanically stable for more than one year of continuous immersion . The slope of the linear calibration plots in the 0-8 mg L(-1) oxygen concentration range (ca . 1.0 L mg(-1)) decreases 8-11% after applying the 50-nm protective layer with no change in the sensor precision (1.1-1.9% RSD, n = 6) . The response time of the 200-microm O2-sensitive layers (1.5-6 min) increases up to 2-fold, depending on the nature of the PC polymer used, but the temperature effect on the sensor response (0.020 L mg(-1) degrees C(-1)) remains essentially unchanged . Oxygen detection limits as low as 0.04 mg L(-1) have been measured with the coated optodes . The novel biofouling-resistant optosensors have been successfully validated against a commercial oxygen electrode and are shown to respond faster than the electrochemical device for large oxygen concentration changes . The biomimetic coatings will be particularly useful for drift-free long-term operation of environmental optosensors and in vivo fiber-optic oxygen analyzers. Am J Gastroenterol, 2001 Nov, 96(11), 3192 - 4 Management of suppurative pylephlebitis by percutaneous drainage: placing a drainage catheter into the portal vein; Pelsang RE et al.; Persistent infection of the portal vein is a rare entity with significant mortality . We present two cases of infected thombis of the portal vein, one infected with fungus and the other with bacteria, both requiring percutaneous drainage to allow a response to antibiotics . The distinction between bland thrombis, infected thrombis, portal venous air, and pneumobilia will be discussed so that suppurative pylephlebitis can be recognized more easily as drain placement appears to affect a more prompt degree of improvement than antibiotics alone. Pest Manag Sci, 2001 Nov, 57(11), 1075 - 80 Effect of some granular insecticides currently used for the treatment of maize crops (Zea mays) on the survival of inoculated Azospirillum lipoferum; Revellin C et al.; Four insecticides, carbofuran, chlormephos, terbufos and benfuracarb, currently used on maize (Zea mays) at sowing, were tested for their compatibility with Azospirillum lipoferum strain CRT1 used as an inoculant to improve maize growth and yield . The growth or survival of A lipoferum was studied in the presence of the insecticides: (1) in liquid and solid cultures of the bacteria, (2) when a commercial inoculant (Azogreen-m, Liphatech, Meyzieu, France) was inoculated directly on insecticide granules, (3) when inoculated Azogreen-m granules were mixed with insecticide granules and (4) when inoculated Azogreen-m granules were delivered separately to the seed bed . Of the four insecticides tested, only terbufos had a slight effect on growth of A lipoferum in solid cultures . All the insecticides decreased the survival of A lipoferum when the bacteria were inoculated directly on to the granules, or when inoculated Azogreen-m granules were mixed with an insecticide . We hypothesize that the discrepancies between bacterial culture tests and survival studies might be explained by the conditions of desiccation encountered during inoculation of the granules . Desiccation stress could increase the toxic effect of the insecticides . We therefore suggest including desiccation stress in the biotest used to assess inoculant-pesticide compatibility. Lung Cancer, 2001 Dec, 34 Suppl 2, S71 - 7 The impact of immune responses on lung cancer and the development of new treatment modalities; Pluygers E et al.; OBJECTIVE: This presentation covers predominantly review data in relation with immune responses initiating and accompanying lung carcinogenesis or- on the contrary-contributing to novel therapeutic developments . Occasionally, personal findings will be considered . RESULTS 1 OF IMMUNE DEFICIENCY: It is known for several decades that cancer incidence (several sites) is increased in subjects receiving immunosuppressive therapy, e.g . to avoid transplant rejection, or suffering from AIDS . We have observed that in areas heavily polluted by industrial activities, resulting in immune deficiency, cancer incidence is increased, notably for lung cancer . On the other hand, neoplastic cells are able to escape the host's immune responses by inducing apoptosis of the effector T lymphocytes . Apoptosis in T-cells is triggered by the interaction of the membrane receptor Fas with its normal ligand Fas L, or an activating antibody . Now lung carcinoma cells have been shown to express Fas L, enabling them to destroy cytolytic T cells . RESULTS 2 OF IMMUNE TREATMENT: It is well over a century ago that interest in the immunotherapy of cancer was aroused by the observation of tumour regressions concomitant with bacterial infection, an observation leading to the development of 'Coley's toxin', a mixture of killed bacteria (presently known to act through the presence of TNF-alpha) . Since these long-standing empirical attempts, a lasting search for immune control of cancer has been initiated, comprising such different approaches as active non-specific immunotherapy, active specific immunotherapy, approaches based on the use of monoclonal antibodies, as well as those depending on cellular immunity and the development of adoptive immunotherapy, and the use of peptide vaccines . These different approaches will be described and their results presented . CONCLUSION: Present state-of-the-art will be discussed and new pathways for development evoked; better understanding of immune mechanisms is opening new avenues for improved treatment efficacy. Org Lett, 2001 Nov 29, 3(24), 3819 - 22 1-Deoxy-D-xylulose: synthesis based on molybdate-catalyzed rearrangement of a branched-chain aldotetrose; Zhao S et al.; 1-Deoxy-D-xylulose has been prepared in seven steps and approximately 21% overall yield from 2,3-O-isopropylidene-D-erythrono-1,4-lactone . The key reaction involves transformation of a branched-chain aldotetrose to the 1-deoxy-2-ketopentose catalyzed by molybdic acid . Other branched-chain aldotetroses containing bulkier substituents at C2 also engage in the conversion, suggesting routes to protected 2-ketoses and alpha-ketoacids/esters . This synthetic route mimics reactions of the non-mevalonate isoprenoid pathway in plants and bacteria . {reaction: see text} J Biol Chem, 2002 Feb 1, 277(5), 3504 - 10 Epub 2001 Nov 21. Membrane topography of the coupling ion binding site in Na+-translocating F1F0 ATP synthase; von Ballmoos C et al.; A carbodiimide with a photoactivatable diazirine substituent was synthesized and incubated with the Na(+)-translocating F(1)F(0) ATP synthase from both Propionigenium modestum and Ilyobacter tartaricus . This caused severe inhibition of ATP hydrolysis activity in the absence of Na(+) ions but not in its presence, indicating the specific reaction with the Na(+) binding c-Glu(65) residue . Photocross-linking was investigated with the substituted ATP synthase from both bacteria in reconstituted 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC)-containing proteoliposomes . A subunit c/POPC conjugate was found in the illuminated samples but no a-c cross-links were observed, not even after ATP-induced rotation of the c-ring . Our substituted diazirine moiety on c-Glu(65) was therefore in close contact with phospholipid but does not contact subunit a . Na(+)in/(22)Na(+)out exchange activity of the ATP synthase was not affected by modifying the c-Glu(65) sites with the carbodiimide, but upon photoinduced cross-linking, this activity was abolished . Cross-linking the rotor to lipids apparently arrested rotational mobility required for moving Na(+) ions back and forth across the membrane . The site of cross-linking was analyzed by digestions of the substituted POPC using phospholipases C and A(2) and by mass spectroscopy . The substitutions were found exclusively at the fatty acid side chains, which indicates that c-Glu(65) is located within the core of the membrane. Adv Drug Deliv Rev, 2001 Nov 19, 52(3), 245 - 53 Towards synthetic viruses; Zuber G et al.; Gene delivery is too complex to be performed with a single carrier molecule . Synthetic multicomponent vectors are being designed that mimic key properties of viruses . Some solutions, such as diverting cell-anchoring molecules or the endogenous nuclear import machinery from their normal function, are directly copied from bacteria and viruses . Some other solutions are original ones: monomolecular genome condensation via detergent dimerization or endosome disruption by the proton sponge effect are not exploited by natural cell invaders . All these components, however, still have to be assembled into a unique supramolecular system, an 'artificial virus'. Adv Drug Deliv Rev, 2001 Nov 19, 52(3), 165 - 76 Approaches for generating recombinant adenovirus vectors; Mizuguchi H et al.; Various methods have been developed to facilitate the generation of recombinant adenovirus vectors, and three commercially available methods have been most widely used: the homologous recombination method in E1-complement cell lines, the homologous recombination method in bacteria, and an in vitro ligation method based on simple routine plasmid construction . These methods can insert foreign genes not only into the E1 deletion region, but also into the E3 deletion region, thereby permitting the construction of a binary transgene expression system in which heterologous genes can be inserted into both the E1 and E3 regions . By modifying the latter two methods, fiber-mutant adenovirus vectors can be also constructed in order to modify vector tropism . In this paper, we review recent advances in the construction of first generation adenovirus vectors and fiber-modified adenovirus vectors. Eur J Surg Suppl, 2001, (586), 66 - 72 Understanding inflammatory bowel disease--the clinician's perspective; Rutgeerts P et al.; The treatment of patients with ulcerative colitis and Crohn's disease is a huge challenge to the clinician mainly because the etiology of IBD is still completely unknown . Pathogenetic mechanisms, in constrast, have partly been elucidated thanks to immunohistochemical investigation of the tissue in IBD and the study of experimental animal models of gut inflammation . There is extensive evidence that at least in Crohn's disease tolerance for commensal bacteria is lost which leads to uncontrolled inflammation mediated by a T-helper 1 response and to tissue destruction of the gut epithelium with inadequate repair . Genetic factors are probably responsible for increased susceptibility and may define disease phenotypes . These insights have led to a dramatic improvement of our therapeutic means with the development of the chimeric monoclonal antibody to TNF . The pathogenetic mechanisms are less clear in UC . The hypothesis is that UC is a T-helper 2 mediated disease . We have a very attractive way to study the early onset of Crohn's disease in the postoperative Crohn's situation . Newer therapeutic approaches should aim at preventing recurrence of Crohn's lesions in the normal postoperative bowel . Such model is also available for UC since there is increasing evidence that pouchitis is recurrent ulcerative colitis in the small bowel . Cooperation between clinicians and basic scientists is the best way to achieve fast progress in understanding IBD. Eur J Surg Suppl, 2001, (586), 30 - 3 New therapeutic possibilities in inflammatory bowel disease; Kamm MA; Therapeutic approaches in inflammatory bowel disease (IBD) involve targeting the broad inflammatory process, targeting specific inflammatory mediators, changing the interior milieu to diminish antigenic drive, or removing the main mediators of inflammation, the inflammatory cells, completely . Recent developments have occurred in each of these therapeutic areas . New steroids, and better use of existing drugs, such as azathioprine and cyclosporin, have improved therapy . Genetically engineered drugs, such as TNF-alpha antibody, offer the prospect of powerful treatment for patients resistant to standard therapies . The use of probiotics offers an entirely new approach, by changing the lumenal milieu . Understanding how bacteria and epithelial cells interact is likely to bring important rewards in therapy . Finally, immune cell replacement may be a possible therapy for severe disease when all else has failed. Eur Biophys J, 2001 Oct, 30(6), 421 - 9 Channel activity of a phytotoxin of Clavibacter michiganense ssp . nebraskense in tethered membranes; Michalke A et al.; Solid-supported membranes immobilized on gold electrodes were used to detect and characterize the spontaneously inserting anion-selective protein channel (Clavibacter anion channel, CAC) present in the culture fluid of Clavibacter michiganense ssp . nebraskense . Three different membrane systems varying in the composition of the first chemisorbed monolayer were investigated by means of impedance spectroscopy . Conductance changes of the immobilized lipid membranes were sensitively detected after adding the culture fluid of the bacteria to the solid-supported membranes, indicating that the relative change in conductance is largest if the lipid layer is attached to the surface via a flexible lipid anchor . Variation in the d.c . potential revealed that CAC exhibits a voltage dependence in these tethered membranes which can be described by an exponential function in accordance with previous results obtained from patchclamp measurements and impedance analysis . The addition of an inhibitor that selectively blocks anion channels abolished the channel conductance almost completely, indicating that the increased conductivity can be attributed to the specific insertion of the CAC . A linear dependence of the channel conductance on the chloride concentration was found, which was modulated by the charges of the second lipid monolayer . The results demonstrate that tethered lipid membranes on gold surfaces in conjunction with impedance spectroscopy allows one to monitor and characterize water-soluble spontaneously inserting channels, providing an effective means to probe for bacterial toxins. Zhonghua Yi Xue Za Zhi, 2001 Aug 25, 81(16), 999 - 1003 {Tumor targeted expression of adenovirus mediated CDglyTK gene regulated by irradiation via Egr-1 promoter}; Wei D et al.; OBJECTIVE: To construct adenoviral vecter of AdEgr-CD/TK in which CDglyTK gene was driven by Egr-1 promoter, and control the tumor targeted expression of CDglyTK gene by gamma irradiation so as to observe the effects of gene-radiotherapy of liver cancer . METHODS: Adenoviral vector of AdEgr-CD/TK was generated through homologous recombination in bacteria . The expression of CDglyTK gene in MM45T . Li cells infected with AdEgr-CD/TK and exposed to different doses of gamma irradiation were analyzed, and the relative survival rate of the cells in presence of prodrugs 5-FC and GCV was tested . In addition, the tumor suppression effects of different treatments were investigated in 64 mice bearing liver cancer by observing the size of tumor at interval of four days . RESULTS: In vitro experiment showed that gamma irradiation markedly and dose-dependently induced CDglyTK expression in MM45T . Li tumor cells, and significantly enhanced the sensitivity of MM45T . Li cells infected with AdEgr-CD/TK to prodrugs 5-FC or GCV resulting in cell being killed (P < 0.01) . A synergetic cytotoxic effect was found when both 5-FC and GCV were added . In vivo experiment revealed that, compared with other control treatments, intratumoral injection of AdEgr-CD/TK combined with intraperitoneal injection of GCV + 5-FC and TLI obviously suppressed tumor growth (P < 0.01), with 30% of the tumor eradicated completely while without causing the increase of whole body cytotoxic effect . CONCLUSION: Tumor targeted expression of CDglyTK gene under the control of irradiation represents a novel strategy for safe and effective gene therapy of cancer and might have wide application in the future. Zhonghua Nei Ke Za Zhi, 2001 Aug, 40(8), 510 - 3 {The transcription of interleukin-8 in gastric epithelial cells by Helicobacter pylori strains in Chinese}; Li S et al.; OBJECTIVE: To observe the effect of the vac A genotype and the existence of cag pathogenicity island (cag PAI) of Helicobacter pylori (Hp) isolated from Chinese patients on the transcription of IL-8 in gastric epithelial cells . METHODS: The genotype of vac A and the existence of cag PAI of Hp were determined by gene sequencing and Southern blot, respectively; the constructed L5F11 cells were cocultured with the bacteria and the transcription of interleukin-8(IL-8) was indicated by luciferase activity and the cytotoxin activity showed by using HeLa cell vacuolating assay . RESULTS: The ability to induce luciferase by the strains with complete cag PAI (n = 15) was much higher than that by the wild cag negative strain G50{(0.47 +/- 0.09) x 10(6) cpm vs (0.13 +/- 0.02) x 10(6) cpm, P < 0.01} and there was no difference in the luciferase activity induced by the strains with partial cag (n = 4) and by G50{(0.23 +/- 0.08) x 10(6) cpm vs (0.13 +/- 0.02) x 10(6) cpm, P > 0.05}; Also no difference was found in the luciferase activity induced by the strains with vac A s1/m1 (n = 5) and the strains with s1/m2 (n = 14) {(0.29 +/- 0.12) x 10(6) cpm vs (0.53 +/- 0.41) x 10(6) cpm, P > 0.05} although the formers had much higher vacuolating cytotoxin activity than the latters (P < 0.001) . CONCLUSION: The transcription of IL-8 in gastric epithelial cells induced by Hp isolated from Chinese patients was associated with the existence of cag PAI and not with the genotype of vac A. J Endotoxin Res, 2001, 7(4), 287 - 91 Toll-like receptor-2 transduces signals for NF-kappa B activation, apoptosis and reactive oxygen species production; Aliprantis AO et al.; The innate immune system coordinates the inflammatory response to pathogens . To do so, cells of the innate immune system must rapidly discriminate between self and non-self . All bacteria express membrane-associated lipoproteins . These molecules activate cells of the innate immune system to initiate host defense mechanisms . However, it is currently unknown how the innate immune system recognizes bacterial lipoproteins . Here, we describe that in response to bacterial lipoprotein, human Toll-like receptor-2 activates three different cellular responses: nuclear factor-kappaB dependent transcription, programmed cell death and reactive oxygen species production . We propose that Toll-like receptor-2 fulfils multiple roles in the genesis of the immune response to bacterial pathogens. Proc Natl Acad Sci U S A, 2001 Nov 20, 98(24), 13814 - 9 Role of positively charged transmembrane segments in the insertion and assembly of mitochondrial inner-membrane proteins; Saint-Georges Y et al.; The biogenesis of membrane oligomeric complexes is an intricate process that requires the insertion and assembly of transmembrane (TM) domains into the lipid bilayer . The Oxa1p family plays a key role in this process in organelles and bacteria . Hell et al . (2001, EMBO J., 20, 1281-1288) recently have proposed that Oxa1p could act as part of a general membrane insertion machinery for mitochondrial respiratory complex subunits . We have previously shown that mutations in the TM domain of Cyt1p can partially compensate for the absence of Oxa1p . Here, we demonstrate that a single amino acid substitution in the TM domain of Qcr9p can bypass Oxa1p in yeast . Qcr9p and Cyt1p are two subunits of the respiratory complex bc1 and their relative roles in the assembly of other respiratory complexes have been investigated . The mutations we have isolated in Cyt1p or Qcr9p introduce positively charged amino acids, and we show that the mutant TM domain of Cyt1p mediates the restoration of complex assembly . We propose that the positive charges introduced in Cyt1p and Qcr9p TM domains promote interactions with negatively charged TM domains of other respiratory complex subunits, allowing the coinsertion of both domains into the membrane, in the absence of Oxa1p . This model argues in favor of a role of Oxa1p in the insertion and the lateral exit of less hydrophobic TM domains from the translocation site into the lipid bilayer. Proc Natl Acad Sci U S A, 2001 Nov 20, 98(24), 13490 - 5 Magnetite morphology and life on Mars; Buseck PR et al.; Nanocrystals of magnetite (Fe(3)O(4)) in a meteorite from Mars provide the strongest, albeit controversial, evidence for the former presence of extraterrestrial life . The morphological and size resemblance of the crystals from meteorite ALH84001 to crystals formed by certain terrestrial bacteria has been used in support of the biological origin of the extraterrestrial minerals . By using tomographic and holographic methods in a transmission electron microscope, we show that the three-dimensional shapes of such nanocrystals can be defined, that the detailed morphologies of individual crystals from three bacterial strains differ, and that none uniquely match those reported from the Martian meteorite . In contrast to previous accounts, we argue that the existing crystallographic and morphological evidence is inadequate to support the inference of former life on Mars. J Biol Chem, 2002 Jan 18, 277(3), 2006 - 11 Epub 2001 Nov 20. A critical role for the Var2 FtsH homologue of Arabidopsis thaliana in the photosystem II repair cycle in vivo; Bailey S et al.; Using a var2-2 mutant of Arabidopsis thaliana, which lacks a homologue of the zinc-metalloprotease, FtsH, we demonstrate that this protease is required for the efficient turnover of the D1 polypeptide of photosystem II and protection against photoinhibition in vivo . We show that var2-2 leaves are much more susceptible to light-induced photosystem II photoinhibition than wild-type leaves . Furthermore, the rate of photosystem II photoinhibition in untreated var2-2 leaves is equivalent to that of var2-2 and wild-type leaves, which have been treated with lincomycin, an inhibitor of the photosystem II repair cycle at the level of D1 synthesis . This is in contrast to untreated wild-type leaves, which show a much slower rate of photosystem II photoinhibition due to an efficient photosystem II repair cycle . The recovery of var2-2 leaves from photosystem II photoinhibition is also impaired relative to wild-type . Using Western blot analysis in the presence of lincomycin we show that the D1 polypeptide remains stable in leaves of the var2-2 mutant under photoinhibitory conditions that lead to D1 degradation in wild-type leaves and that the abundance of DegP2 is not affected by the var2-2 mutation . We conclude, therefore, that the Var2 FtsH homologue is required for the cleavage of the D1 polypeptide in vivo . In addition, we identify a conserved lumenal domain in Var2 that is unique to FtsH homologues from oxygenic phototrophs. J Bacteriol, 2001 Dec, 183(24), 7408 - 11 NAD(P)-dependent aldehyde dehydrogenases induced during growth of Ralstonia eutropha strain Bo on tetrahydrofurfuryl alcohol; Schrader T et al.; Different aldehyde dehydrogenases (AlDHs) were formed during growth of Ralstonia eutropha Bo on tetrahydrofurfuryl alcohol (THFA) . One of these enzymes, AlDH 4, was purified and characterized as a homodimer containing no prosthetic groups, showing a strong substrate inhibition, and having an N-terminal sequence similar to those of various NAD(P)-dependent AlDHs . The conversion rate of THFA by the quinohemoprotein THFA dehydrogenase was increased by AlDH 4. J Bacteriol, 2001 Dec, 183(24), 7387 - 91 Stability and subcellular localization of cytadherence-associated protein P65 in Mycoplasma pneumoniae; Jordan JL et al.; The surface protein P65 is a constituent of the Mycoplasma pneumoniae cytoskeleton and is present at reduced levels in mutants lacking the cytadherence accessory protein HMW2 . Pulse-chase studies demonstrated that P65 is subject to accelerated turnover in the absence of HMW2 . P65 was also less abundant in noncytadhering mutants lacking HMW1 or P30 but was present at wild-type levels in mutants lacking proteins A, B, C, and P1 . P65 exhibited a polar localization like that in wild-type M . pneumoniae in all mutants having normal levels of HMW1 and HMW2 . Partial or complete loss of these proteins, however, correlated with severe reduction in the P65 level and the inability to localize P65 properly. Clin Orthop, 2001 Nov, (392), 377 - 82 Gout-induced arthropathy after total knee arthroplasty: a report of two cases; Archibeck MJ et al.; Gout, although relatively rare in joint replacements, can present as an acute or chronic painful knee or hip arthroplasty . Gout and acute infection of a joint replacement can be difficult to differentiate, with the physical examination and laboratory study results frequently being similar . Both conditions can present with a rapid onset of joint pain, swelling, erythema, and constitutional symptoms, including fevers and malaise . Laboratory findings in both conditions often include an elevated leukocyte count, erythrocyte sedimentation rate, and C-reactive protein level . Negatively birefringent, needle-shaped crystals in the synovial fluid confirm the diagnosis of gout . The mistaken diagnosis of septic arthritis in a joint replacement with crystal-induced synovitis can lead to inappropriate open debridement or component removal . The current study includes a review of the literature and presents two cases of gout after total knee arthroplasty . These cases suggest that in situations of suspected sepsis without synovial fluid crystals, operative intervention is indicated with a presumed diagnosis of septic arthritis . The identification of chalky white or yellow deposits in the synovium or bone is highly suggestive of gout . The definitive diagnosis is made by polarized light histologic evaluation of these tissues . If these deposits are present in the absence of a positive preoperative culture, positive Gram stain for bacteria, or component loosening, component retention is indicated. Am J Trop Med Hyg, 2001 Nov, 65(5), 603 - 9 Tissue diagnosis of Ehrlichia chaffeensis in patients with fatal ehrlichiosis by use of immunohistochemistry, in situ hybridization, and polymerase chain reaction; Dawson JE et al.; In the United States, human ehrlichiosis is a complex of emerging tick-borne diseases caused by 3 distinct Ehrlichia species: Ehrlichia chaffeensis, Ehrlichia ewingii, and the human granulocytotropic ehrlichiosis agent . Ehrlichioses are characterized by a mild to severe illness, and approximately 4% of cases are fatal . Because these obligate intracellular bacteria are difficult to resolve with routine histologic techniques, their distribution in tissues has not been well described . To facilitate the visualization and detection of ehrlichiae, immunohistochemistry (IHC), in situ hybridization (ISH), and polymerase chain reaction (PCR) assays were developed by use of tissues from 4 fatal cases of E . chaffeensis infection . Evidence of E . chaffeensis via IHC, ISH, and PCR was documented in all 4 cases . Abundant immunostaining and in situ nucleic acid hybridization were observed in spleen and lymph node from all 4 patients . Significantly, in 2 of these patients, serologic evidence of infection was absent . Use of IHC, ISH, and PCR to visualize and detect Ehrlichia in tissues can facilitate diagnosis of ehrlichial infections. Curr Opin Mol Ther, 1999 Apr, 1(2), 204 - 15 Therapeutic mammalian artificial episomal chromosomes; Vos JM; Two general strategies are being developed to engineer mammalian artificial chromosomes (MACs) as therapeutic vectors: (i) in vitro MAC cloning by enzymatic ligation of the individual MAC components followed by propagation in single cell organisms such as bacteria or yeast; and (ii) in situ MAC assembly by co-introduction of the various MAC elements into an 'incubator' mammalian tissue culture cell and use of it as a 'foster parental' donor cell . Because of their organizational compactness, in vitro built MACs are stuitable for somatic-based human gene therapy . In contrast, the long-term persistence of in situ built MACs can be capitalized on to generate husbandry transgenic animals expressing therapeutic genes . While current MAC systems generally rely on cis-elements exclusively from viral or genomic origin, the next generation of MACs may combine both into chimeric systems . As illustration of the genetic flexibility and technological potential of chimeric MACs, the herpes viral oriP/EBNA1 system, paradigm of a self-replicating and self-segregating episome in human cells is discussed in terms of future therapeutic applications. J Gen Virol, 2001 Dec, 82(Pt 12), 2935 - 43 The NS5A protein of bovine viral diarrhoea virus interacts with the alpha subunit of translation elongation factor-1; Johnson CM et al.; A cellular protein that interacts with the NS5A polypeptide of bovine viral diarrhoea virus (BVDV) was identified in a yeast two-hybrid screen . The NS5A interactor was identified as the alpha subunit of bovine translation elongation factor 1A (eEF1A) . Cell-free binding studies were performed with chimeric NS5A fused to glutathione S-transferase (GST-NS5A) expressed in bacteria . GST-NS5A bound specifically to both in vitro-translated and mammalian cell-expressed eEF1A . Moreover, purified eEF1A bound specifically to GST-NS5A attached to a solid phase . Conservation of this interaction was then analysed using a set of NS5A proteins derived from divergent BVDV strains encompassing known biotypes and genotypes . NS5A from all BVDV strains tested so far interacted with eEF1A . The conserved association of eEF1A with virus molecules involved in genome replication and the postulated role of pestivirus and hepacivirus NS5A in replication indicate that this interaction may play a role in the replication of BVDV. J Immunol, 2001 Dec 1, 167(11), 6545 - 51 Fc receptor-mediated immunity against Bordetella pertussis; Rodriguez ME et al.; The relevance of specific Abs for the induction of cellular effector functions against Bordetella pertussis was studied . IgG-opsonized B . pertussis was efficiently phagocytosed by human polymorphonuclear leukocytes (PMN) . This process was mediated by the PMN IgG receptors, FcgammaRIIa (CD32) and FcgammaRIIIb (CD16), working synergistically . Furthermore, these FcgammaR triggered efficient PMN respiratory burst activity and mediated transfer of B . pertussis to lysosomal compartments, ultimately resulting in reduced bacterial viability . Bacteria opsonized with IgA triggered similar PMN activation via FcalphaR (CD89) . Simultaneous engagement of FcalphaRI and FcgammaR by B . pertussis resulted in increased phagocytosis rates, compared with responses induced by either isotype alone . These data provide new insights into host immune mechanisms against B . pertussis and document a crucial role for Ig-FcR interactions in immunity to this human pathogen. J Biol Chem, 2002 Feb 1, 277(5), 3727 - 32 Epub 2001 Nov 19. Crystal structure of quinohemoprotein alcohol dehydrogenase from Comamonas testosteroni: structural basis for substrate oxidation and electron transfer; Oubrie A et al.; Quinoprotein alcohol dehydrogenases are redox enzymes that participate in distinctive catabolic pathways that enable bacteria to grow on various alcohols as the sole source of carbon and energy . The x-ray structure of the quinohemoprotein alcohol dehydrogenase from Comamonas testosteroni has been determined at 1.44 A resolution . It comprises two domains . The N-terminal domain has a beta-propeller fold and binds one pyrroloquinoline quinone cofactor and one calcium ion in the active site . A tetrahydrofuran-2-carboxylic acid molecule is present in the substrate-binding cleft . The position of this oxidation product provides valuable information on the amino acid residues involved in the reaction mechanism and their function . The C-terminal domain is an alpha-helical type I cytochrome c with His(608) and Met(647) as heme-iron ligands . This is the first reported structure of an electron transfer system between a quinoprotein alcohol dehydrogenase and cytochrome c . The shortest distance between pyrroloquinoline quinone and heme c is 12.9 A, one of the longest physiological edge-to-edge distances yet determined between two redox centers . A highly unusual disulfide bond between two adjacent cysteines bridges the redox centers . It appears essential for electron transfer . A water channel delineates a possible pathway for proton transfer from the active site to the solvent. Pharmacotherapy, 2001 Nov, 21(11 Pt 2), 319S - 330S Pharmacodynamics of antiinfective therapy: taking what we know to the patient's bedside; Rodvold KA; Applied pharmacokinetics has long been a lifeline of clinical pharmacy services . National surveys during the past decade documented clinical pharmacy services and demonstrated that a substantial rate of growth occurred in clinical pharmacokinetic consultations and management of drug therapy protocols . Pharmacodynamic principles of antiinfective agents are rapidly becoming a new paradigm of clinical pharmacy services . beta-Lactams, aminoglycosides, and fluoroquinolones represent the three classes of antiinfective agents that have made the most progress toward the clinical applications of pharmacodynamics . Pharmacodynamic parameters are being used to select and compare agents within an antiinfective class (e.g., fluoroquinolones), make modifications in the dosage (e.g., extended-interval dosing of aminoglycosides) and/or mode of administration (e.g., continuous infusion of beta-lactams), develop in vivo breakpoint determinations, and assess the development of bacterial resistance . In addition, pharmacodynamic parameters have influenced the clinical drug development of new (e.g., linezolid) and older (amoxicillin-clavulanate, fluoroquinolones) antiinfective agents . Further investigations are needed to explore the clinician's use of validated prediction methods and patient-specific pharmacodynamic parameters at the bedside . By linking pharmacokinetic services with pharmacodynamic principles, the opportunity for continued progress toward our assessment and decisions for successful clinical outcomes is possible with old and new antiinfective agents. Dig Dis Sci, 2001 Nov, 46(11), 2378 - 84 Immunologic influences of hyperthermia in a rat model of obstructive jaundice; Gulluoglu BM et al.; In this study, the effect of hyperthermia on immune response and bacterial translocation from the gut in jaundiced rats was assessed . In hyperthermic (HP; N = 8) and normothermic (NP; N = 8) preconditioning groups, rats were preconditioned by hyperthermia for 15 min at 42 degrees C or 38 degrees C, respectively . After 8 hr, the common bile duct (CBD) of each animal was ligated . In thermal (TT; N = 8) and normothermic treatment groups (NT; N = 8) the CBD of the animals was ligated, and after seven days rats were treated by hyperthermia for 15 min at 42 degrees C and 38 degrees C, respectively . The rats in the preconditioning groups (HP and NP) were killed at day 7 and rats in the treatment groups (TT and NT) were killed 8 hr after they were put in a water bath . Determination of the immunophenotypes of lymphocytes and serum levels of bilirubin was done in serum samples taken just after death . The quantity and identify of translocated bacteria were determined in tissue samples of mesenteric lymph nodes, spleen, and liver . NK cell expression as well as CD4+/CD8+ ratio were elevated in HP group when compared to NP group . CD8+ expression was found to be low in HP group when compared to NP group . CD4+, CD11b+, and B cell expressions were not found to be different between HP and NP groups . All immunologic parameters were similar when TT and NT groups were compared to each other . In the TT group, half of the rats revealed bacterial translocation, whereas in all other groups, we determined translocation in only 1/8 rats . The application of hyperthermia as preconditioning rather than applying it after the establishment of jaundice seemed to be beneficial . Hyperthermic preconditioning led an improvement in immune responses whereas the latter resulted an increase in bacterial translocation with no favorable influence on immune system . Bacterial translocation was unrelated with the immune status. Nucleic Acids Res, 2001 Nov 15, 29(22), 4509 - 17 RadA protein from Archaeoglobus fulgidus forms rings, nucleoprotein filaments and catalyses homologous recombination; McIlwraith MJ et al.; Proteins that catalyse homologous recombination have been identified in all living organisms and are essential for the repair of damaged DNA as well as for the generation of genetic diversity . In bacteria homologous recombination is performed by the RecA protein, whereas in the eukarya a related protein called Rad51 is required to catalyse recombination and repair . More recently, archaeal homologues of RecA/Rad51 (RadA) have been identified and isolated . In this work we have cloned and purified the RadA protein from the hyperthermophilic, sulphate-reducing archaeon Archaeoglobus fulgidus and characterised its in vitro activities . We show that (i) RadA protein forms ring structures in solution and binds single- but not double-stranded DNA to form nucleoprotein filaments, (ii) RadA is a single-stranded DNA-dependent ATPase at elevated temperatures, and (iii) RadA catalyses efficient D-loop formation and strand exchange at temperatures of 60-70 degrees C . Finally, we have used electron microscopy to visualise RadA-mediated joint molecules, the intermediates of homologous recombination . Intriguingly, RadA shares properties of both the bacterial RecA and eukaryotic Rad51 recombinases. Optometry, 2001 Oct, 72(10), 649 - 52 Possible iatrogenic transmission of Creutzfeldt-Jakob disease via tonometer tips: a review of the literature; Walia JS et al.; BACKGROUND: Tonometer tips are used by optometrists to measure intraocular pressures . The recommended procedure of soaking in bleach solution kills bacteria and certain viruses, such as human immunodeficiency virus, herpes simplex virus-1 and herpes simplex virus-2, adenovirus 8, and hepatitis B, from the tip . Conversely, recommendations made in literature to sterilize equipment that may have come in contact with virus-contaminated tissue from patients with Creutzfeldt-Jakob disease have a somewhat tougher requirement . METHODS: Autoclaving for 1 hour at a temperature of at least 120 degrees C (15 psi), or a 1-hour exposure to 0.5% sodium hypochlorite (a 10-fold dilution of household bleach) should provide excellent disinfection . One-hour exposure to 1 N Sodium hydroxide has also been mentioned in the literature . RESULTS: Studies have shown that corneas of guinea pigs with Cruetzfeldt-Jakob disease (C-J disease) are infectious . Infected corneas have been shown to cause transmission via corneal transplants, and via experimental placement of infected guinea pig's cornea into the anterior chamber of uninfected guinea pigs . Many researchers have strongly suggested that C-J disease can be iatrogenically transmitted via applanation tonometer tips . An epidemiologic case-controlled study found statistically significant odds ratio for intraocular pressure testing in the medical history of patients with C-J disease . CONCLUSION: Even though there have not been any proven studies confirming iatrogenic transmission through tonometer tips, optometrists should be cautious if a patient has C-J disease, or manifests symptoms of C-J disease and use alternatives to Goldmann applanation tonometry. Rocz Akad Med Bialymst, 2000, 45, 78 - 86 Effect of aquatic macrophytes on the quantity of bacterioplankton; Czeczuga B et al.; The authors investigated the effect of aquatic macrophytes on the quantity of bacterioplankton . Among the 7 species of aquatic macrophytes the most pronounced effect on bacterioplankton is exerted by Potamogeton crispus, causing a decrease in its quantity to 53.28% . Polygonum amphibium stimulates the growth of bacteria to 121.96% . Under the influence of macrophytes the spherical to cylindrical ratio changes from 1:1.31 (Lemna minor) to 1:2.07 (Potamogeton crispus). Rocz Akad Med Bialymst, 2000, 45, 68 - 77 Effect of the cyanobacterium Anabaena spiroides Klebahn on the quantity of bacterioplankton in water of varied trophicity; Czeczuga B et al.; The authors investigated the effect of the cyanobacterium Anabaena spiroides on the quantity of bacterioplankton in water of varied trophicity . The cyanobacterium Anabaena spiroides, introduced to the polluted water of the river Biala has the strongest effect on bacterioplankton--the number of bacteria decreases to 31.78% . The spherical:cylindrical ratio changes in favour of the latter when affected by the cyanobacterium . This is the most pronounced in the river Biala, where spherical:cylindrical changes from 1:0.88 to 1:1.96 . Anabaena spiroides exerts the most significant effect on the quantity of bacterioplankton in lake Sniardwy and pond Fosa after 24 hours, and in the other water bodies after 72 hours following the introduction of the cyanobacterium. Microb Pathog, 2001 Nov, 31(5), 243 - 53 HpaA shows variable surface localization but the gene expression is similar in different Helicobacter pylori strains; Lundstrom AM et al.; Due to earlier contradictory results regarding the localization of the putative Helicobacter pylori adhesin A (HpaA), we aimed to compare the gene and protein expression and surface localization of HpaA in different H . pylori strains . Five H . pylori strains were cultivated for 11 days and analysed by Northern blot analysis, flow cytometry (FCM), semi-quantitative dot blot, colony blot, immuno-electron microscopy (IEM), and phase-contrast microscopy . The highest transcriptional activity of the hapA gene as observed after 3-4 days of cultivation and two mRNA transcripts of 1600 and 3100 nucleotides, respectively, were detected in all five strains with the hpaA probe . We also showed by reverse transcription-polymerase chain reaction (RT-PCR) that the hpaA gene is co-transcribed with the downstream omp18 gene . The highest total HpaA protein production in bacteria occurred between day 3 and 7, as determined by semi-quantitative dot blot, and was similar in the different strains . The maximal proportion of cells with HpaA on the bacterial surface, detected by FCM, was for strain SS1, 90%; Hel 344, 60%; CCUG 17875, 61%; CCUG 17874, 86% and for strain AH 244 only 35% . By IEM HpaA was detected in all strains both on the bacterial surface and on the flagellar sheath . Semin Nucl Med, 2001 Oct, 31(4), 286 - 95 Radiopharmaceuticals to image infection and inflammation; Boerman OC et al.; Scintigraphic imaging of infection and inflammation is a powerful diagnostic tool in the management of patients with infectious or inflammatory diseases . Most infectious and inflammatory foci can be visualized accurately with radiolabeled autologous leukocytes . However, the preparation of this radiopharmaceutical is laborious and requires the handling of potentially contaminated blood . A few radiopharmaceuticals are available that could be used instead of radiolabeled leukocytes to scintigraphically visualize infectious and inflammatory foci, such as 67Ga-citrate and 99mTc-labeled antigranulocyte antibody preparations . Various agents labeled with 99mTc are currently developed for this application . Most of these newly developed agents are ligands that bind receptors on white blood cell subpopulations, ie, monoclonal antibodies, chemotactic peptides, and cytokines . Furthermore, agents are developed that potentially could distinguish between infection and nonmicrobial inflammation . In addition, 18F-fluorodeoxyglucose positron emission tomography imaging was proposed to visualize inflammatory foci when a high spatial resolution is required . In this article, the characteristics and diagnostic potential of established and experimental radiopharmaceuticals for infection and inflammation imaging are reviewed. J Vet Med A Physiol Pathol Clin Med, 2001 Oct, 48(8), 475 - 86 Mycoplasma hyosynoviae arthritis in grower-finisher pigs; Nielsen EO et al.; The aetiology of acute lameness in pigs 3-5 months of age in nine Danish herds with high incidences of lameness was investigated . Eighty-seven acutely lame pigs, that exhibited lameness of varying degree in the hind legs, were selected . Non-lame pigs were matched on pen, sex and weight . The lame pigs had soft fluctuating joint swellings (odds ratio (OR), 7.21; 95% confidence interval (CI), 3.41-15.47) . No indication of suppurative arthritis was observed . Joint infection with Mycoplasma hyosynoviae was found by culture in 20% (17 of 86) of the lame pigs and in 8% (seven of 83) of the non-lame pigs . Lameness and joint infection with M . hyosynoviae were significantly associated . Other ordinary bacteria were not found in any case . Macroscopic osteochondrotic lesions were observed at slaughter in 47% (37 of 78) of the previously lame pigs and in 35% (55 of 158) of an enlarged group without history of lameness . The cubital joints were most frequently affected and a history of hind leg lameness was not statistically associated with osteochondrotic lesions at slaughter (OR, 1.69; 95% CI, (1.94-3.05), or joint infection with M . hyosynoviae at slaughter (OR, 0.88; 95% CI, 0.31-2.40) . Arthritis due to M . hyosynoviae infection was the primary cause of acute and severe lameness in grower-finisher pigs . Moreover, M . byosynoviae was isolated from joints of several pigs without signs of lameness . This suggests that M . hyosynoriae may be present in joints without provoking clinical illness . The mean daily incidence of treatments due to lameness in the herds was 5.4 per 1,000 pigs . Joint disease implied 30-90 min extra labour for surveillance and treatment every day per 1,000 pigs, and 5% of the affected individuals were euthanized due to lameness . The average daily weight gains in the selected pigs until slaughter seemed unaffected by the lameness. Ann R Australas Coll Dent Surg, 2000 Oct, 15, 141 - 3 Prognosis--the dilemma of modern periodontics; Pearlman B; As periodontics has progressed towards an understanding of the influences of risk factors such as genetics, smoking and stress in the occurrence and severity of periodontal disease, the question of prognosis, so essential to treatment planning, has become even more perplexing to the clinician . A survey of long term clinical practice gives insight into the outcome of therapy relative to initial severity, and modern concepts of bacteria versus host relationships provide directions for greater predictability . However, it is only with observation over time that a more accurate assessment of prognosis can be made, as response to initial therapeutic measures can be determined. Ann Rheum Dis, 2001 Dec, 60(12), 1141 - 4 Risk factors and prognostic influence of infection in a single cohort of 87 adults with systemic lupus erythematosus; Noel V et al.; OBJECTIVES: To describe infectious complications and analyse their risk factors and prognostic role in adults with systemic lupus erythematosus (SLE) . METHODS: A monocentric cohort of 87 adults with SLE (1960-1997) was studied to determine the risk factors for infection (disease activity evaluated by SLAM and SLEDAI scores, type of organ(s) involved or any biological abnormality, specific treatments) by comparing patients who had suffered at least one infectious episode (n=35; 40%) with non-infected patients (n=52; 60%) . Prognostic indicators were assessed by comparing survivors at 10 years with non-survivors . RESULTS: Of the 57 infectious episodes, 47 (82%) were of bacterial origin, 16 (28%) were pneumonia, and 46 (81%) were community acquired . According to univariate analysis, significant risk factors for infection were: severe flares, lupus glomerulonephritis, oral or intravenous corticosteroids, pulse cyclophosphamide, and/or plasmapheresis . No predictors were identified at the time of SLE diagnosis . Multivariate analyses retained intravenous corticosteroids (p<0.001) and/or immunosuppressants (p<0.01) as independent risk factors for infection, which was the only factor for death after 10 years of evolution (p<0.001) . CONCLUSION: In adults with SLE, infections are common and most often caused by community acquired bacteria . Intravenous corticosteroids and immunosuppressants are independent risk factors for infection, which is the only independent risk factor for death after 10 years of SLE evolution. Semin Immunol, 2001 Dec, 13(6), 347 - 55 Actin dynamics during phagocytosis; Castellano F et al.; Bacteria, apoptotic cells and other particulate material are taken up through phagocytosis, a conserved cellular function driven by actin polymerization . As reviewed here, small GTPases of the Rho family, their activators and effectors control the local reorganization of the actin cytoskeleton underneath bound particles . Remarkably, the molecular actors and regulatory mechanisms involved during phagocytosis through the FcR or the CR3 receptors are very similar to those underlying the cytoskeletal rearrangements that take place at the leading edge of motile cell and at adhesion sites, respectively . J Theor Biol, 2001 Nov 7, 213(1), 73 - 88 Regulation of gene expression in flux balance models of metabolism; Covert MW et al.; Genome-scale metabolic networks can now be reconstructed based on annotated genomic data augmented with biochemical and physiological information about the organism . Mathematical analysis can be performed to assess the capabilities of these reconstructed networks . The constraints-based framework, with flux balance analysis (FBA), has been used successfully to predict time course of growth and by-product secretion, effects of mutation and knock-outs, and gene expression profiles . However, FBA leads to incorrect predictions in situations where regulatory effects are a dominant influence on the behavior of the organism . Thus, there is a need to include regulatory events within FBA to broaden its scope and predictive capabilities . Here we represent transcriptional regulatory events as time-dependent constraints on the capabilities of a reconstructed metabolic network to further constrain the space of possible network functions . Using a simplified metabolic/regulatory network, growth is simulated under various conditions to illustrate systemic effects such as catabolite repression, the aerobic/anaerobic diauxic shift and amino acid biosynthesis pathway repression . The incorporation of transcriptional regulatory events in FBA enables us to interpret, analyse and predict the effects of transcriptional regulation on cellular metabolism at the systemic level . Anim Health Res Rev, 2001 Jun, 2(1), 75 - 82 Classification of Brachyspira spp . isolated from Swedish dogs; Fellstrom C et al.; Brachyspira spp . were isolated from 21 of 32 sampled dogs (66%) in a colony of Swedish beagle dogs with a history of diarrhea and from 3 of 17 Swedish pet dogs (17%) with diarrhea . All Swedish isolates were weakly beta-hemolytic and gave a negative indole reaction . Eighty-eight percent showed negative alpha-galactosidase and hippurate reactions, but a positive beta-glucosidase reaction . Two isolates were hippurate positive with a negative beta-glucosidase reaction . One additional German isolate diverged by showing a positive indole reaction in combination with a positive hippurate reaction . Sequencing of 16S rDNA indicated that the hippurate-positive isolates belonged to the species Brachyspira pilosicoli . Four representative isolates were examined using pulsed-field gel electrophoresis (PFGE) and compared with six reference strains and five porcine isolates of Brachyspira spp . The canine isolates clustered together in the PFGE analysis . Necropsy examination of a culture-positive B . pilosicoli colony-raised beagle dog revealed macro- and microscopical lesions of colitis with numerous spiral-shaped bacteria in the lumens of the crypts, in goblet cells and within the colonic epithelium. Anim Health Res Rev, 2001 Jun, 2(1), 3 - 17 Comparative pathology and pathogenesis of naturally acquired and experimentally induced colonic spirochetosis; Duhamel GE; Research in the past decade has led to the recognition of Brachyspira (formerly Serpulina) pilosicoli as the primary etiologic agent of colonic spirochetosis (CS), an emerging cause of colitis in humans and animals . Attachment of spirochetes to the epithelial surface of the lower intestine is considered to be the hallmark of CS . However, because B . pilosicoli, B . aalborgi and unclassified flagellated bacteria are found singly or together in humans and non-human primates with CS lesions, attachment of spiral-shaped bacteria may not represent the same etiopathogenetic entity in all hosts . Moreover, North American opossums with CS are infected with B . aalborgi-like spirochetes together with flagellated bacteria, whereas B . pilosicoli is found alone in dogs, pigs, chickens and other species of birds with CS . Conversely, guinea-pigs with CS have unidentified spirochetes that may be B . pilosicoli or B . aalborgi . The pig model of CS suggests that attachment of B . pilosicoli to epithelial cells may be transient . By contrast, persistence of B . pilosicoli in the cecal and colonic crypt lumina, chronic inflammation caused by spirochetal invasion into the subepithelial lamina propria and translocation to extraintestinal sites may be more important than previously thought . This review describes the lesions seen in naturally occurring and experimentally induced CS of animals, and it sets the stage for future research into the pathogenic mechanisms of infection and colitis caused by B . pilosicoli. J Rheumatol, 2001 Nov, 28(11), 2487 - 93 Use of a peptide based enzyme immunoassay in diagnosis of Chlamydia trachomatis triggered reactive arthritis; Nikkari S et al.; OBJECTIVE: To assess the presence of circulating IgA and IgG antibodies to Chlamydia trachomatis in sera of patients with reactive arthritis (ReA) and other arthritides . METHODS: A peptide based enzyme immunoassay (EIA) was used to study 132 patients divided into 5 groups: C . trachomatis triggered ReA, uroarthritis, enteroarthritis, oligoarthritis, and rheumatoid arthritis (RA) . Followup sera were available from 19 patients . RESULTS: An increased prevalence of C . trachomatis antibodies was observed in patients with ReA triggered by C . trachomatis; 18/23 (78%) had IgA and 19/23 (83%) had IgG antibodies . In patient groups with uroarthritis (n = 12), enteroarthritis (n = 56), oligoarthritis (n = 16), and RA (n = 25), C . trachomatis IgA/IgG antibodies were detected in 58%/75%, 27%/21%, 25%/31%, and 20%/32% of patients, respectively . Both the IgA and IgG antibodies were positive in 74%, 50%, 16%, 25%, and 12% of the patients with C . trachomatis triggered ReA, uroarthritis, enteroarthritis, oligoarthritis, and RA, respectively . Based on positivity of both isotypes the sensitivity of the assay was 74% and specificity 84% . In the followup sera, an association between circulating C . trachomatis-specific antibody concentrations and clinical disease outcome of the arthritis was seen in patients with culture-positive C . trachomatis triggered ReA . CONCLUSION: C . trachomatis species-specific peptide EIA correlates well with conventional diagnosis of primary C . trachomatis infection in patients with ReA . This assay may be a valuable contribution to the diagnosis of C . trachomatis triggered ReA. Protein Eng, 2001 Sep, 14(9), 615 - 31 Pectin degrading glycoside hydrolases of family 28: sequence-structural features, specificities and evolution; Markovic O et al.; Family 28 belongs to the largest families of glycoside hydrolases . It covers several enzyme specificities of bacterial, fungal, plant and insect origins . This study deals with all available amino acid sequences of family 28 members . First, it focuses on the detailed analysis of 115 sequences of polygalacturonases yielding their evolutionary tree . The large data set allowed modification of some of the existing family 28 sequence characteristics and to draw the sequence features specific for bacterial and fungal exopolygalacturonases discriminating them from the endopolygalacturonases . The evolutionary tree reflects both the taxonomy and specificity so that bacterial, fungal and plant enzymes form their own clusters, the endo- and exo-mode of action being respected, too . The only insect (animal) representative is most related to fungal endopolygalacturonases . The present study brings further: (i) the analysis of available rhamnogalacturonase sequences; (ii) the elucidation of relatedness between the recently added member, the endo-xylogalacturonan hydrolase and the rest of the family; and (iii) revealing the sequence features characteristic of the individual enzyme specificities and the evolutionary relationships within the entire family 28 . The disulfides common for the individual enzyme groups were also proposed . With regard to functionally important residues of polygalacturonases, xylogalacturonan hydrolase possesses all of them, while the rhamnogalacturonases, known to lack the histidine residue (His223; Aspergillus niger polygalacturonase II numbering), have a further tyrosine (Tyr291) replaced by a conserved tryptophan . Evolutionarily, the xylogalacturonan hydrolase is most related to fungal exopolygalacturonases and the rhamnogalacturonases form their own cluster on the adjacent branch. J Exp Biol, 2001 Oct, 204(Pt 20), 3403 - 9 Phototransduction in Drosophila melanogaster; Hardie RC; As in most invertebrate microvillar photoreceptors, phototransduction in Drosophila melanogaster uses a G-protein-coupled phosphoinositide pathway, whereby hydrolysis of phosphatidyl inositol 4,5-bisphosphate (PIP(2)) by phospholipase C generates inositol 1,4,5-trisphosphate (InsP(3)) and diacyl glycerol (DAG), leading to activation of two classes of Ca(2+)-permeable light-sensitive channel, encoded by the trp and trpl genes . In some invertebrate photoreceptors, excitation is mediated by release of Ca(2+) from intracellular stores by InsP(3); however, in Drosophila melanogaster, recent evidence suggests instead that a lipid messenger, such as DAG, its metabolites and/or the reduction in PIP(2) levels, may mediate excitation . Like vertebrate rods, Drosophila melanogaster photoreceptors generate quantum bumps in response to single photons, but their kinetics is approximately 10-100 times faster, and this reflects a fundamentally different strategy incorporating a threshold, positive and negative feedback by Ca(2+) acting downstream of phospholipase C and a refractory period. Vet Parasitol, 2001 Nov 22, 101(3-4), 291 - 310 Advances and prospects for subunit vaccines against protozoa of veterinary importance; Jenkins MC; Protozoa are responsible for considerable morbidity and mortality in domestic and companion animals . Preventing infection may involve deliberate exposure to virulent or attenuated parasites so that immunity to natural infection is established early in life . This is the basis for vaccines against theilerosis and avian coccidiosis . Vaccination may not be effective or practical with diseases, such as cryptosporidiosis, that primarily afflict the immune-compromised or individuals with an incompletely developed immune system . Strategies for combating these diseases often rely on passive immunotherapy using serum or colostrums containing antibodies to parasite surface proteins . Subunit vaccines offer an attractive alternative to virulent or attenuated parasites for several reasons . These include the use of bacteria or lower eukaryotes to produce recombinant proteins in batch culture, the relative stability of recombinant proteins compared to live parasites, and the flexibility to incorporate only those antigens that elicit "protective" immune responses . Although subunit vaccines offer many theoretical advantages, our lack of understanding of immune mechanisms to primary and secondary infection and the capacity of many protozoa to evade host immunity remain obstacles to developing effective vaccines . This review examines the progress made on developing recombinant proteins of Eimeria, Giardia, Cryptosporidium, Toxoplasma, Neospora, Trypanosoma, Babesia, and Theileria and attempts to use these antigens for vaccinating animals against the associated diseases. FEBS Lett, 2001 Nov 9, 508(1), 1 - 4 Inter-domain cross-talk controls the NifA protein activity of Herbaspirillum seropedicae; Monteiro RA et al.; Herbaspirillum seropedicae is an endophytic diazotroph, which colonizes sugar cane, wheat, rice and maize . The activity of NifA, a transcriptional activator of nif genes in H . seropedicae, is controlled by ammonium ions through a mechanism involving its N-terminal domain . Here we show that this domain interacts specifically in vitro with the N-truncated NifA protein, as revealed by protection against proteolysis, and this interaction caused an inhibitory effect on both the ATPase and DNA-binding activities of the N-truncated NifA protein . We suggest that the N-terminal domain inhibits NifA-dependent transcriptional activation by an inter-domain cross-talk between the catalytic domain of the NifA protein and its regulatory N-terminal domain in response to fixed nitrogen. J Dent Res, 2001 Oct, 80(10), 1875 - 9 Tumor necrosis factor modulates fibroblast apoptosis, PMN recruitment, and osteoclast formation in response to P . gingivalis infection; Graves DT et al.; P . gingivalis is an important oral pathogen, which has been closely linked to periodontal disease as well as lesions of endodontic origin . Both infections are associated with a decrease in fibroblast numbers, formation of an inflammatory infiltrate, and bone resorption . The goal of this study was to investigate the role that the host response plays in the capacity of P . gingivalis to stimulate fibroblast apoptosis, PMN recruitment, and osteoclastogenesis . This was accomplished by the use of an in vivo calvarial model in mice with targeted deletion of TNF receptors p55 and p75 and matched wild-type mice . The results indicate that P . gingivalis induces fibroblast apoptosis in vivo and establish for the first time that this involves the stimulation of a host response . Moreover, bacteria-stimulated PMN recruitment and osteoclastogenesis were also dependent upon the host response . The results suggest that much of the damage caused by P . gingivalis infection, including fibroblast apoptosis, at least under some circumstances, results from stimulation of the host response rather than the direct effect of bacterial products . Furthermore, this may represent a more general mechanism by which bacterial challenge induces apoptosis of matrix-producing cells through the induction of TNF. J Biol Chem, 2002 Jan 18, 277(3), 2202 - 6 Epub 2001 Nov 08. Ubiquinone is necessary for Caenorhabditis elegans development at mitochondrial and non-mitochondrial sites; Hihi AK et al.; Ubiquinone (UQ) is a lipid co-factor that is involved in numerous enzymatic processes and is present in most cellular membranes . In particular, UQ is a crucial electron carrier in the mitochondrial respiratory chain . Recently, it was shown that clk-1 mutants of the nematode worm Caenorhabditis elegans do not synthesize UQ(9) but instead accumulate demethoxyubiquinone (DMQ(9)), a biosynthetic precursor of UQ(9) (the subscript refers to the length of the isoprenoid side chain) . DMQ(9) is capable of carrying out the function of UQ(9) in the respiratory chain, as demonstrated by the functional competence of mitochondria isolated from clk-1 mutants, and the ability of DMQ(9) to act as a co-factor for respiratory enzymes in vitro . However, despite the presence of functional mitochondria, clk-1 mutant worms fail to complete development when feeding on bacteria that do not produce UQ(8) . Here we show that clk-1 mutants cannot grow on bacteria producing only DMQ(8) and that worm coq-3 mutants, which produce neither UQ(9) nor DMQ(9), arrest development even on bacteria producing UQ(8) . These results indicate that UQ is required for nematode development at mitochondrial and non-mitochondrial sites and that DMQ cannot functionally replace UQ at those non-mitochondrial sites. Infect Immun, 2001 Dec, 69(12), 7922 - 6 Limited mycobacterial infection of the liver as a consequence of its microanatomical structure causing restriction of mycobacterial growth to professional phagocytes; Seiler P et al.; Among sites of extrapulmonary growth of Mycobacterium tuberculosis, the liver is the least infected . Our data suggest that this is due to the complete restriction of mycobacterial growth to liver macrophages . Unlike in organs more persistently seeded by M . tuberculosis, in the liver the bacteria do not infect cell types other than professional phagocytes. Infect Immun, 2001 Dec, 69(12), 7736 - 42 Brucella abortus genes identified following constitutive growth and macrophage infection; Eskra L et al.; The chronicity of Brucella abortus infection in humans and animals depends on the organism's ability to escape host defenses by gaining entry and surviving inside the macrophage . Although no human vaccine exists for Brucella, vaccine development in other bacteria has been based on deletions of selective nutritional as well as regulatory systems . Our goal is to develop a vaccine for Brucella . To further this aim, we have used a green fluorescent protein (GFP) reporter system to identify constitutively and intracellularly induced B . abortus genes . Constitutively producing gfp clones exhibited sequence homology with genes associated with protein synthesis and metabolism (initiation factor-1 and tRNA ribotransferase) and detoxification (organic hydroperoxidase resistance) . Of greater interest, clones negative for constitutively produced gfp in agar were examined by fluorescence microscopy to detect promoter activity induced within macrophages 4 and 24 h following infection . Bacterial genes activated in macrophages 4 h postinfection appear to be involved in adapting to intracellular environmental conditions . Included in this group were genes for detoxification (lactoglyglutathione lyase gene), repair (formamidopyrimidine-DNA glycosylase gene), osmotic protection (K(+) transport gene), and site-specific recombination (xerD gene) . A gene involved in metabolism and biosynthesis (deoxyxylulose 5' phosphate synthase gene) was also identified . Genes activated 24 h following infection were biosynthesis- and metabolism-associated genes (iron binding protein and rhizopine catabolism) . Identification of B . abortus genes that are activated following macrophage invasion provides insight into Brucella pathogenesis and thus is valuable in vaccine design utilizing selective targeted deletions of newly identified Brucella genes. Infect Immun, 2001 Dec, 69(12), 7729 - 35 Role of complement in Mycobacterium avium pathogenesis: in vivo and in vitro analyses of the host response to infection in the absence of complement component C3; Bohlson SS et al.; We investigated the importance of the host complement system in the pathogenesis of disease mediated by the intramacrophage pathogen Mycobacterium avium . Mycobacteria opsonized with complement are efficiently ingested by macrophages through various complement receptors . Furthermore, unlike other bacteria, mycobacteria can activate both the alternative and classical complement pathways in the absence of specific antibodies . Therefore, to examine the role of complement in the mycobacterial infection process in vivo, mice deficient in complement component C3 were infected with M . avium . Surprisingly, C3-deficient mice infected intravenously with M . avium displayed no difference in bacterial burden or granulomatous response compared to wild-type control mice . C3-sufficient mice and C3-deficient mice were equally susceptible to infection by M . avium regardless of the genotype at the bcg locus, a locus known to confer susceptibility to infection with intracellular pathogens . In vitro studies using mouse bone marrow-derived macrophages resulted in significant M . avium invasion of macrophages in the absence of C3; however, the kinetics of infection were delayed compared to complement-mediated invasion . The data indicate that complement does not play an essential role in mediating M . avium infections in the mouse and suggest either that other invasion mechanisms can compensate for the absence of complement-mediated entry or that complement is not a major mycobacterial opsonin in vivo. Infect Immun, 2001 Dec, 69(12), 7635 - 41 Pertussis toxin and lipopolysaccharide influence phagocytosis of Bordetella pertussis by human monocytes; Schaeffer LM et al.; The potential of human monocytes to mediate the clearance of Bordetella pertussis infection was examined . Bacteria expressing green fluorescent protein were incubated with adherent peripheral blood monocytes, and phagocytosis was quantified by using fluorescence microscopy . Monocytes internalized only a small percentage of the adherent bacteria . Surface-associated Bvg-regulated virulence factors, including adenylate cyclase toxin and filamentous hemagglutinin, did not affect attachment or phagocytosis . However, 1-h pretreatment with purified pertussis toxin inhibited the ability of monocytes to internalize wild-type bacteria . Mutations affecting the terminal trisaccharide of lipopolysaccharide resulted in reduced internalization without affecting adherence of bacteria to monocytes . Opsonization with human serum played only a modest role in promoting phagocytosis . The viability of internalized bacteria was determined by colony counts following treatment with polymyxin B and gentamicin . Less than 1% of internalized bacteria remained viable . These results suggest that pertussis toxin plays a role in the evasion of monocyte phagocytosis and that these cells represent a potential mediator of the clearance of B . pertussis infection. Infect Immun, 2001 Dec, 69(12), 7501 - 11 Mycobacterial protein HbhA binds human complement component C3; Mueller-Ortiz SL et al.; Mycobacterium tuberculosis and Mycobacterium avium are facultative intracellular pathogens that are able to survive and replicate in mononuclear phagocytes . Human complement component C3 has previously been shown to mediate attachment and phagocytosis of these bacteria by mononuclear phagocytes . In this study, a C3 ligand affinity blot protocol was used to identify a 30-kDa C3-binding protein in M . tuberculosis and Mycobacterium smegmatis and a 31-kDa C3-binding protein in M . avium . The C3-binding proteins in M . tuberculosis and M . avium localized to the cell membrane fraction and partitioned to the detergent fraction during Triton X-114 phase partitioning . The C3-binding protein from M . tuberculosis was partially purified using a cation exchange column and was shown to bind concanavalin A . The N terminus and an internal fragment of the partially purified C3-binding protein were subjected to amino acid sequence analysis . The resulting amino acid sequences matched the M . tuberculosis heparin-binding hemagglutinin (HbhA) protein . Recombinant full-length HbhA and the C terminus of HbhA fused to maltose-binding protein, but not recombinant HbhA lacking the C-terminal region, bound human C3 . Recombinant full-length HbhA coated on polystyrene beads, was found to enhance the adherence and/or phagocytosis of the coated beads to J774.A1 cells in both the presence and absence of human serum . The presence of complement-sufficient serum increased the adherence of the HbhA-coated beads to the J774.A1 cells in a C3-dependent manner . If HbhA within the bacterial cell membrane functions similarly to isolated HbhA, this protein may enhance the adherence and phagocytosis of M . tuberculosis and M . avium to mononuclear phagocytes through the binding of C3 and interaction with C3 receptors on mononuclear phagocytes. Infect Immun, 2001 Dec, 69(12), 7349 - 55 Mycobacterium tuberculosis chaperonin 60.1 is a more potent cytokine stimulator than chaperonin 60.2 (Hsp 65) and contains a CD14-binding domain; Lewthwaite JC et al.; Much attention has focused on the Mycobacterium tuberculosis molecular chaperone chaperonin (Cpn) 60.2 (Hsp 65) in the pathology of tuberculosis because of its immunogenicity and ability to directly activate human monocytes and vascular endothelial cells . However, M . tuberculosis is one of a small group of bacteria that contain multiple genes encoding Cpn 60 proteins . We have now cloned and expressed both M . tuberculosis proteins and report that the novel chaperonin 60, Cpn 60.1, is a more potent inducer of cytokine synthesis than is Cpn 60.2 . This is in spite of 76% amino acid sequence similarity between the two mycobacterial chaperonins . The M . tuberculosis Cpn 60.2 protein activates human peripheral blood mononuclear cells by a CD14-independent mechanism, whereas Cpn 60.1 is partially CD14 dependent and contains a peptide sequence whose actions are blocked by anti-CD14 monoclonal antibodies . The cytokine-inducing activity of both chaperonins is extremely resistant to heat . Cpn 60.1 may be an important virulence factor in tuberculosis, able to activate cells by diverse receptor-driven mechanisms. Heredity, 2001 Aug, 87(Pt 2), 227 - 33 Sex ratio and Wolbachia infection in the ant Formica exsecta; Keller L et al.; Sex allocation data in social Hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories . However, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio . It has been suggested that maternally inherited parasites may influence sex allocation in social Hymenoptera . If the parasites can influence sex allocation, infected colonies are predicted to invest more resources in females than non-infected colonies, because the parasites are transmitted through females but not males . Prime candidates for such sex ratio manipulation are Wolbachia, because these cytoplasmically transmitted bacteria have been shown to affect the sex ratio of host arthropods by cytoplasmic incompatibility, parthenogenesis, male-killing and feminization . In this study, we tested whether Wolbachia infection is associated with colony sex ratio in two populations of the ant Formica exsecta that have been the subject of extensive sex ratio studies . In these populations colonies specialize in the production of one sex or the other . We found that almost all F . exsecta colonies in both populations are infected with Wolbachia . However, in neither population did we find a significant association in the predicted direction between the prevalence of Wolbachia and colony sex ratio . In particular, colonies with a higher proportion of infected workers did not produce more females . Hence, we conclude that Wolbachia does not seem to alter the sex ratio of its hosts as a means to increase transmission rate in these two populations of ants. Sheng Wu Gong Cheng Xue Bao, 2001 Jul, 17(4), 467 - 70 {Studies on asymmetric synthesis of R-phenylethanolamine by whole cells of Arachnia sp . P163}; Wang JL et al.; Effects of various factors on asymmetric synthesis of R-phenylaminoethanol from aminoacetophenone by the whole cells of Arachnia sp . P163 producing alcohol dehydrogenase for phenylethanol amine was investigated . It found that, although the reduction was inhibited by the substrate and the product, but it has the very high stereoselectivity . The reduction was normaly carried out with 2% glucose for reproduction of coenzyme in the reaction system without oxygen . The conversion yield and ee value of the product achieved 65% and 100%, respectively. Arch Microbiol, 2001 Nov, 176(5), 323 - 8 Amorphous mineral phases in magnetotactic multicellular aggregates; Lins U et al.; Magnetotactic multicellular aggregates consist of several bacteria that produce iron sulfide magnetosomes through a complex and poorly understood process . We observed new amorphous mineral particles within the cytoplasm of magnetotactic multicellular aggregates . Elemental mapping and electron energy loss spectroscopy detected iron and oxygen, but not sulfur, in these particles . These amorphous particles were about the same size as mature magnetosomes, around 50-70 nm in diameter . No membranes were observed surrounding the amorphous minerals . Partially crystalline inclusions composed of a crystalline core and an amorphous region around them similar in texture to the amorphous particles were also present . The shape of these amorphous regions followed the shape of the crystalline cores they enveloped . These regions also contained oxygen and iron . The crystalline phase, as previously reported, contained sulfur and iron . The presence of independent amorphous particles has not been reported before in magnetotactic multicellular aggregates. Science, 2001 Nov 9, 294(5545), 1334 - 6 Collaboration between CC- and A-adding enzymes to build and repair the 3'-terminal CCA of tRNA in Aquifex aeolicus; Tomita K et al.; The universal 3'-terminal CCA sequence of all transfer RNAs (tRNAs) is repaired, and sometimes constructed de novo, by the CCA-adding enzyme {ATP(CTP):tRNA nucleotidyltransferase} . This RNA polymerase has no nucleic acid template, yet faithfully builds the CCA sequence one nucleotide at a time using cytidine triphosphate (CTP) and adenosine triphosphate (ATP) as substrates . All previously characterized CCA-adding enzymes from all three kingdoms are single polypeptides with CCA-adding activity . Here, we demonstrate through biochemical and genetic approaches that CCA addition in Aquifex aeolicus requires collaboration between two related polypeptides, one that adds CC and another that adds A. Annu Rev Phytopathol, 2001, 39, 187 - 224 Pathogen fitness penalty as a predictor of durability of disease resistance genes; Leach JE et al.; Host plant resistance has been used extensively for disease control in many crop species; however, the resistance conferred by many sources is not durable as a result of rapid changes in the pathogen . Although many resistance genes have been identified in plant germplasm, there is no easy way to predict the quality or durability of these resistance genes . In this review, we revisit the hypothesis that resistance genes imposing a high penalty to the pathogen for adaptation will likely be durable . By elucidating the molecular changes involved in pathogen adaptation and the associated fitness cost, a proactive approach may be developed to predict the durability of resistance genes available for deployment. Annu Rev Biomed Eng, 2000, 2, 339 - 76 Antibody engineering; Maynard J et al.; Antibodies are unique in their high affinity and specificity for a binding partner, a quality that has made them one of the most useful molecules for biotechnology and biomedical applications . The field of antibody engineering has changed rapidly in the past 10 years, fueled by novel technologies for the in vitro isolation of antibodies from combinatorial libraries and their functional expression in bacteria . This review presents an overview of the methods available for the de novo generation of human antibodies, for engineering antibodies with increased antigen affinity, and for the production of antibody fragments . Select applications of recombinant antibodies are also presented. Cell, 2001 Nov 2, 107(3), 339 - 46 Differential gene expression governed by chromosomal spatial asymmetry; Dworkin J et al.; The activity of the transcription factor sigmaF is confined to one (the forespore) of two cells created by asymmetric division during sporulation in B . subtilis . We show that sigmaF activation is partly governed by the position of the gene for the unstable anti-sigmaF factor SpoIIAB . Because cytokinesis precedes chromosome segregation, most of the chromosome is translocated into the forespore after division . We hypothesize that because spoIIAB enters the forespore late, SpoIIAB lost to proteolysis is temporarily not replenished . Thus, chromosome asymmetry would be translated into the asymmetric distribution of SpoIIAB . Supporting this idea, transposition of spoIIAB to sites present in the forespore at the time of division impaired sporulation when a second pathway that participates in sigmaF activation was disabled. Anal Biochem, 2001 Nov 15, 298(2), 151 - 62 Detection of epitope-tagged proteins in flow cytometry: fluorescence resonance energy transfer-based assays on beads with femtomole resolution; Buranda T et al.; Epitope tagging of expressed proteins is a versatile tool for the detection and purification of the proteins . This approach has been used in protein-protein interaction studies, protein localization, and immunoprecipitation . Among the most popular tag systems is the FLAG epitope tag, which is recognized by three monoclonal antibodies M1, M2, and M5 . We describe novel approaches to the detection of epitope-tagged proteins via fluorescence resonance energy transfer on beads . We have synthesized and characterized biotinylated and fluorescein-labeled FLAG peptides and examined the binding of FLAG peptides to commercial streptavidin beads using flow cytometric analysis . A requirement of assay development is the elucidation of parameters that characterize the binding interactions between component systems . We have thus compiled a set of Kd values determined from a series of equilibrium binding experiments with beads, peptides, and antibodies . We have defined conditions for binding biotinylated and fluoresceinated FLAG peptides to beads . Site occupancies of the peptides were determined to be on the order of several million sites per bead and Kd values in the 0.3-2.0 nM range . The affinity for antibody attachment to peptides was determined to be in the low nanomolar range (less than 10 nM) for measurements on beads and solution . We demonstrate the applicability of this methodology to assay development, by detecting femtomole amounts of N-terminal FLAG-bacteria alkaline phosphatase fusion protein . These characterizations form the basis of generalizable and high throughput assays for proteins with known epitopes, for research, proteomic, or clinical applications . Optom Vis Sci, 2001 Oct, 78(10), 732 - 43 The role of fenestrations and channels on the transverse motion of a soft contact lens; Chauhan A et al.; PURPOSE: Ineffectual removal of potentially harmful species from the postlens tear film (POLTF) may lead to adverse responses among extended wearers of soft contact lenses . It is apparently important to remove bacteria, cell debris, and metabolic products from the postlens tear film to the outer tear lake; the flushing or dispersion rate of these species is enhanced by increasing fluid movement in the tear film driven by periodic lens motion . The contact lens moves laterally (up-down) and transversally (in-out) due to the action of the eyelid forces during blinking . Viscous drag in the POLTF resists lens motion . Consequently, any design change in the lens that reduces viscous drag increases motion and improves flushing of unwanted species from the POLTF . We investigate quantitatively the effect of channels cut on the back surface of the lens and fenestrations (holes) drilled through the lens on transverse lens motion . METHODS: We model the lens as a curved solid body with a periodic arrangement of channels/holes . The cornea is treated as a flat surface, and the hydrodynamic equations of motion are solved for Newtonian fluid transport in the POLTF assuming lubrication and creeping flow . POLTF pressure profiles, obtained by solving these equations, are integrated to determine the lens settling velocity in the transverse direction for a given amount of applied lid force . Lens settling velocity is then compared with the same velocity in the absence of channels/fenestrations . Further, we calculate the total transverse motion in a blink for lenses with and without channels/fenestrations to estimate the possible enhancement in transverse motion due to the channels/fenestrations . RESULTS: Variables that affect the fluid mixing in the POLTF are the postlens tear film thickness, lens thickness, channel length, depth and spacing, and the hole diameter, location, and spacing . We study the effect of each of these variables on the enhancement of transverse motion for channels and holes of diameters varying from 0.1 to 2 mm with spacing varying from 1 to 5 mm . CONCLUSIONS: We demonstrate that incorporation of channels and holes reduces viscous resistance and increases transverse lens motion, and thus increases fluid mixing and dispersive flushing from the POLTF . The increase in transverse motion depends strongly on the postlens tear film thickness . Enhancement of the transverse motion varies from a factor of about 2 to 20 depending on the particular lens design and the postlens tear film thickness . Because fluid mixing increases up to the square of the transverse motion, channels/holes are expected to render flushing of the POLTF considerably more effective . We find that channels and/or fenestrations, when appropriately designed, can provide significant improvement in flushing from the POLTF . This work provides a new quantitative tool for the efficient design of channels/holes in soft contact lenses. Genome Inform Ser Workshop Genome Inform, 2000, 11, 161 - 71 Intrinsic protein disorder in complete genomes; Dunker AK et al.; Intrinsic protein disorder refers to segments or to whole proteins that fail to fold completely on their own . Here we predicted disorder on protein sequences from 34 genomes, including 22 bacteria, 7 archaea, and 5 eucaryotes . Predicted disordered segments > or = 50, > or = 40, and > or = 30 in length were determined as well as proteins estimated to be wholly disordered . The five eucaryotes were separated from bacteria and archaea by having the highest percentages of sequences predicted to have disordered segments > or = 50 in length: from 25% for Plasmodium to 41% for Drosophila . Estimates of wholly disordered proteins in the bacteria ranged from 1% to 8%, averaging to 3 +/- 2%, estimates in various archaea ranged from 2 to 11%, plus an apparently anomalous 18%, averaging to 7 +/- 5% that drops to 5 +/- 3% if the high value is discarded . Estimates in the 5 eucarya ranged from 3 to 17% . The putative wholly disordered proteins were often ribosomal proteins, but in addition about equal numbers were of known and unknown function . Overall, intrinsic disorder appears to be a common, with eucaryotes perhaps having a higher percentage of native disorder than archaea or bacteria. Microbiology, 2001 Nov, 147(Pt 11), 3127 - 34 In vitro secretion kinetics of proteins from Legionella pneumophila in comparison to proteins from non-pneumophila species; Flieger A et al.; It has been shown that the loss of PilD, a prepilin peptidase necessary for type IV pilus biogenesis and establishment of the type II secretion apparatus is associated with loss of virulence in Legionella pneumophila . L . pneumophila is the species most frequently associated with Legionnaires' disease, but virulence factors unique to this species are not known, so the secretion kinetics of several pilD-dependent enzyme activities, including protease, acid phosphatase, phospholipase A (PLA) and lysophospholipase A (LPLA), of L . pneumophila and non-pneumophila species were compared during growth in BYE broth . Enzyme activity appeared during mid-exponential growth phase and reached maximal levels on entry into stationary growth phase . None of the enzyme activities were unique to L . pneumophila and it did not exclusively secrete the highest amounts of the hydrolytic proteins . However, the timing of PLA and LPLA secretion in L . pneumophila differed compared to other species . PLA activity was secreted prior to LPLA activity in L . pneumophila, which may lead to an accumulation of the cytotoxic agent lysophosphatidylcholine (LPC) . In addition to L . pneumophila, several other Legionella species, including Legionella steigerwaltii and Legionella gormanii, were able to enrich for LPC due to a very potent PLA activity accompanied by only moderate LPLA activity . These species, in contrast to L . pneumophila, have not been shown to multiply within monocytic host cells . Thus none of the secreted enzymic activities investigated were unique to L . pneumophila, nor were they secreted at high concentrations . However, the timing of PLA and LPLA secretion may contribute to pathogenicity. J Magn Reson, 2001 Nov, 153(1), 69 - 74 Ferromagnetic resonance of horse spleen ferritin: core blocking and surface ordering temperatures; Wajnberg E et al.; In nature, ferritin, an iron-storage molecule, is found in species ranging from bacteria to man . In the past 50 years its chemical, physical, and magnetic properties have been studied, searching to relate function and structure . Horse spleen ferritin has been investigated by EPR at temperatures between 7 and 290 K . These spectra change from an isotropic line at 290 K to an anisotropic one at 19 K, with a behavior consistent with a system of particles that undergoes superparamagnetic relaxation . A blocking temperature of (116+/-9) K is obtained . A new temperature-dependent signal is observed in the low field region at temperatures higher than 80 K . At 7 K no EPR signal appears, suggesting (14+/-5) K as the Neel temperature of surface spins . Analysis of the temperature dependence of the distance between EPR lines extrema, under the view of two theoretical models, allowed the evaluation of magnetic parameters . These parameters are 2K/M=2.7 x 10(3) Oe and MV=1.9 x 10(-17) emu or K/M=1.3 x 10(3) Oe and MV=2.0 x 10(-17) emu, where K is the anisotropy energy per unit volume, M is the sample magnetization, and V is the superparamagnetic core volume . The results are also discussed, and some structural models in the literature are considered . J Mol Biol, 2001 Nov 9, 313(5), 941 - 54 Comparison of repressor and transcriptional attenuator systems for control of amino acid biosynthetic operons; Elf J et al.; In bacteria, expression from amino acid biosynthetic operons is transcriptionally controlled by two main mechanisms with principally different modes of action . When the supply of an amino acid is in excess over demand, its concentration will be high and when the supply is deficient the amino acid concentration will be low . In repressor control, such concentration variations in amino acid pools are used to regulate expression from the corresponding amino acid synthetic operon; a high concentration activates and a low concentration inactivates repressor binding to the operator site on DNA so that initiation of transcription is down or up-regulated, respectively . Excess or deficient supply of an amino acid also speeds or slows, respectively, the rate by which the ribosome translates mRNA base triplets encoding this amino acid . In attenuation of transcription, it is the rate by which the ribosome translates such "own" codons in the leader of an amino acid biosynthetic operon that decides whether the RNA polymerase will continue into the operon, or whether transcription will be aborted (attenuated) . If the ribosome rate is fast (excess synthesis of amino acid), transcription will be terminated and if the rate is slow (deficient amino acid supply) transcription will continue and produce more messenger RNAs.Repressor and attenuation control systems have been modelled mathematically so that their behaviour in living cells can be predicted and their system properties compared . It is found that both types of control systems are unexpectedly sensitive when they operate in the cytoplasm of bacteria . In the repressor case, this is because amino acid concentrations are hypersensitive to imbalances between supply and demand . In the attenuation case, the reason is that the rate by which ribosomes translate own codons is hypersensitive to the rate by which the controlled amino acid is synthesised.Both repressor and attenuation mechanisms attain close to Boolean properties in vivo: gene expression is either fully on or fully off except in a small interval around the point where supply and demand of an amino acid are perfectly balanced.Our results suggest that repressors have significantly better intracellular performance than attenuator mechanisms . The reason for this is that repressor, but not attenuator, mechanisms can regulate expression from biosynthetic operons also when transfer RNAs are fully charged with amino acids so that the ribosomes work with maximal speed . J Dent Educ, 2001 Oct, 65(10), 1038 - 45 Inherited risks for susceptibility to dental caries; Shuler CF; Dental caries incidence is affected by host factors that may be related to the structure of dental enamel, immunologic response to cariogenic bacteria, or the composition of saliva . Genetic variation of the host factors may contribute to increased risks for dental caries . This systematic review examined the literature to address the question, "Is the risk for dental decay related to patterns of genetic inheritance?" Numerous reports have described a potential genetic contribution to the risk for dental caries . Studies on twins have provided strong evidence for the role of inheritance . Establishing a basis for a genetic contribution to dental caries will provide a foundation for future studies utilizing the human genome sequence to improve understanding of the disease process . Inherited disorders of tooth development with altered enamel structure increase the incidence of dental caries . Specific genetic linkage has not been determined for all of the syndromes of altered tooth development . Consequently, genetic screens of large populations for genes or mutations associated with increased caries susceptibility have not been done . Altered immune response to the cariogenic bacteria may also increase the incidence of caries . Association between specific patterns of HLA genetic inheritance and dental caries risk is weak and does not provide a predictable basis for predicting future decay rates . The evidence supporting an inherited susceptibility to dental caries is limited . Genetic linkage approaches on well-characterized populations with clearly defined dental caries incidence will be required to further analyze the relationship between inheritance and dental caries. IUBMB Life, 2001 May, 51(5), 295 - 8 Identification of a transactivation motif in the CLN3 protein; Leung KY et al.; A transactivation motif has been identified in the neurodegenerative disease protein, CLN3 . The C-terminal domain (residues 394-438) of CLN3 can function as a transcriptional activator when fused to the DNA binding domain, LexA . A series of deletion and substitution constructs have been generated to identify the essential region for transactivation . A similar motif is also present in the POU domain transcription factor, nubbin . However, this domain alone does not activate transcription, allowing further localisation of the critical residues in CLN3 required for activity. IUBMB Life, 2001 May, 51(5), 289 - 93 Partial recovery of light-independent chlorophyll biosynthesis in the chlL-deletion mutant of Synechocystis sp . PCC 6803; Wu Q et al.; A chlL-deletion mutant of Synechocystis sp . PCC 6803 designated as chlL- was unable to make significant amounts of chlorophyll in darkness . However, an apparent pseudorevertant has been generated spontaneously that can synthesize an increased amount of chlorophyll under light-activated heterotrophic growth conditions . Under these conditions, the chlorophyll content in this pseudorevertant was about 20% of that in the wild-type strain and about 4 times more than that in the original and in the recently recreated chlL-deletion mutant . This is paralleled by increased performance of dark-grown cells in terms of chlorophyll fluorescence induction and oxygen evolution rates in the pseudorevertant versus in the original mutant . PCR analysis confirmed that the chlL- -pseudorevertant mutant still lacked the chlL gene . These results imply that the light-independent chlorophyll biosynthesis pathway was partly recovered. Membr Cell Biol, 2001 Jul, 14(5), 673 - 97 Hydrophobicity and prediction of the secondary structure of membrane proteins and peptides; Klevanik AV; Reliability of the hydropathy method to predict the formation of membrane-spanning alpha-helices by integral membrane proteins and peptides whose structure is known from X-ray crystallography is analysed . It is shown that Kyte-Doolittle hydropathy plots do not predict accurately 22 transmembrane alpha-helices in the reaction centres (RC) of the photosynthetic bacteria Rhodopseudomonas viridis and Rhodobacter sphaeroides (R-26) . The accuracy of prediction for these proteins was improved using an optimised Kyte-Doolittle hydrophobicity scale . However, this hydrophobicity scale did not improve the predictions for the alphabeta-peptides of the B800-850 (LH2) complexes of the photosynthetic bacteria Rhodopseudomonas acidophila and Rhodospirillum molischianum, which were excluded from the optimisation procedure . The best and worst predictions of membrane-spanning alpha-helices for the RC proteins and LH2 peptides, respectively, were obtained with a propensity scale (PRC) calculated from the amino acid sequences and X-ray data for the RC proteins . A propensity scale (PLH) obtained using the amino acid sequences and X-ray data for the alphabeta-peptides of the LH2 complexes did not give an acceptable prediction of the transmembrane segments in the LH2 peptides; moreover, it markedly contradicted the PRC scale . Amino acids have been concluded to have no significant preference to localisation in transmembrane segments . Therefore, the predictive ability of the hydropathy methodology appears to be limited: the number of transmembrane segments can be correctly calculated for the best case only, and the lengths and positions of membrane-spanning alpha-helices in a protein amino acid sequence can not be predicted exactly. J Periodontol, 2001 Oct, 72(10), 1332 - 9 Non-redundant roles for interleukin-1 alpha and interleukin-1 beta in regulating human IgG2; Ishihara Y et al.; BACKGROUND: Serum concentrations of immunoglobulin G2 (IgG2) are elevated in localized aggressive periodontitis (LAgP) patients, and secretory products of monocytes from LAgP patients enhance IgG2 responses of lymphocytes from healthy subjects . Furthermore, genes regulating production of interleukin (IL)-1 influence the risk for both aggressive periodontitis (AgP) and chronic periodontitis . These observations, and the fact that IgG2 dominates responses to carbohydrates from Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, prompted the hypothesis that IL-1 alpha, IL-1 beta, and IL-RA may help regulate human IgG2 responses . METHODS: Human peripheral blood leukocytes (PBL) were stimulated in culture with pokeweed mitogen (PWM); the levels of available IL-1 gene products were manipulated; and the effect on IgG2 production was monitored . Manipulations of IL-1 were accomplished by adding specific neutralizing monoclonal antibodies or recombinant IL-1RA, IL-1 alpha, or IL-1 beta . RESULTS: Blocking the IL-1 receptor with IL-1RA or neutralizing IL-1 alpha or IL-1 beta with specific antibody dramatically suppressed IgG2 production (50% to 70%) . Additionally IL-1 alpha did not compensate for neutralized IL-1 beta, and additional IL-1 beta did not compensate for neutralized IL-1 alpha, suggesting the 2 monokines have separate roles in promoting IgG2 . Furthermore, combinations of anti-IL-1 alpha and anti-IL-1 beta were more inhibitory than either antibody alone, and IL-1 alpha and IL-1 beta in combination appeared to work additively in promoting IgG2 . Moreover, PBL cultures from a group of LAgP patients with high IgG2 levels had elevated levels of IL-1 beta . CONCLUSION: IL-1 alpha and IL-1 beta appear to have critical and non-redundant roles in the generation and regulation of potent IgG2 responses, which appear to be important in human responses to carbohydrate-bearing bacteria. J Bacteriol, 2001 Dec, 183(23), 6951 - 6 The LexA protein from Deinococcus radiodurans is not involved in RecA induction following gamma irradiation; Narumi I et al.; The involvement of LexA in induction of RecA was investigated in Deinococcus radiodurans . As in the wild-type strain, an increase in RecA protein synthesis following gamma irradiation was detected in a lexA disruptant, indicating that LexA is not involved in the induction of RecA in D . radiodurans. J Bacteriol, 2001 Dec, 183(23), 6801 - 6 Transcriptional regulation of furA and katG upon oxidative stress in Mycobacterium smegmatis; Milano A et al.; The DNA region upstream of katG in Mycobacterium smegmatis was cloned and sequenced . The furA gene, highly homologous to Mycobacterium tuberculosis furA, mapped in this region . The furA-katG organization appears to be conserved among several mycobacteria . The transcription pattern of furA and katG in M . smegmatis upon oxidative stress was analyzed by Northern blotting and primer extension . Although transcription of both furA and katG was induced upon oxidative stress, transcripts covering both genes could not be identified either by Northern blotting or by reverse transcriptase PCR . Specific transcripts and 5' ends were identified for furA and katG, respectively . By cloning M . smegmatis and M . tuberculosis DNA regions upstream of a reporter gene, we demonstrated the presence of two promoters, pfurA, located immediately upstream of the furA gene, and pkatG, located within the terminal part of the furA coding sequence . Transcription from pfurA was induced upon oxidative stress . A 23-bp sequence overlapping the pfurA -35 region is highly conserved among mycobacteria and streptomycetes and might be involved in controlling pfurA activity . Transcription from a cloned pkatG, lacking the upstream pfurA region, was not induced upon oxidative stress, suggesting a cis-acting regulatory role of this region. J Bacteriol, 2001 Dec, 183(23), 6787 - 93 The global regulators GacA and