Indian J Ophthalmol, 2002 Mar, 50(1), 35 - 9 Further investigations on the association of Mycobacterium tuberculosis with Eales' disease; Madhavan HN et al.; PURPOSE: To apply polymerase chain reaction (PCR) on vitreous fluid (VF) from Eales' disease to further confirm its association with Mycobacterium tuberculosis . METHODS: Sixty nine VF samples from 69 patients (24 Eales' disease and 45 Non-Eales' as controls) were processed by conventional methods for detection of mycobacteria . Polymerase chain reaction (PCR) specific for IS 6110 and nested PCR (nPCR) using primers coding for MPB 64 gene were applied on all 69 VF . PCR based dot-blot hybridisation was applied on the IS 6110 amplified products of n PCR-positive VFs . RESULTS: Conventional methods (direct smear and culture) did not detect mycobacteria in any of the 69 VF samples . Five (20.8%) of 24 VF from Eales' and 2 (4.2%) of 45 VF from control patients tested positive for M . tuberculosis DNA by nPCR . This difference was statistically significant (P < 0.05) . All 69 VF were negative by PCR for IS 6110 . Two VF of Eales' patients positive by nPCR were also positive by DNA probe dot-blot hybridisation for IS 6110 . CONCLUSION: Detection of M . tuberculosis DNA by PCR in a significant number of VF of Eales' disease patients reemphasizes the association of this bacterium with Eales' disease. Proc Natl Acad Sci U S A, 2002 Jul 9, 99(14), 9568 - 72 Epub 2002 Jun 27. Assaying gene content in Arabidopsis; Allen KD; Arabidopsis has been popular as a model plant system for decades . Completion of the Arabidopsis genome and the availability of large expressed sequence-tag collections from other dicot species provides an opportunity to assess gene content in Arabidopsis, specifically by identifying genes from dicot test species that are absent from Arabidopsis . I report here results from these sorts of comparisons, carried out in part to assess the extent to which Arabidopsis is representative of dicot genomes and also the degree to which gene loss and novel gene acquisition has accompanied angiosperm speciation . More than 10% of the contigs from each of three dicot test species have no detectable homologue in Arabidopsis . By means of cross comparison among the test species, 154 specific cases of gene loss in the lineage leading to Arabidopsis were identified, including several well characterized enzymes and a group of proteins with strong homologs in the photosynthetic bacterium Synechocystis . These results show that although Arabidopsis is broadly representative of the other dicot genomes, there seems to be substantial variation even among relatively closely related genera . Further, although we cannot yet draw a causative link, variation in actual gene content seems appears to be a feature of angiosperm speciation. J Clin Microbiol, 2002 Jul, 40(7), 2626 - 8 Large-scale outbreak of infection with Mycobacterium chelonae subsp . abscessus after penicillin injection; Zhibang Y et al.; An outbreak of infection with Mycobacterium chelonae subsp . abscessus after the injection of penicillin in 86 patients attending a factory hospital is reported . The bacterium was isolated both from lids and from the soil where the drug was stored . Molecular analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and plasmids revealed a pattern identical to that of the strains isolated from the wounds . The source of the infections was soil contamination of the vial lids and was caused by improper use and sterilization of penicillin vials. J Clin Microbiol, 2002 Jul, 40(7), 2513 - 9 Helicobacter marmotae sp . nov . isolated from livers of woodchucks and intestines of cats; Fox JG et al.; Woodchucks (Marmota monax) have a high incidence of hepatocellular carcinoma (HCC) associated with chronic infection with woodchuck hepatitis virus (WHV) and serve as a model of hepatitis B virus-associated HCC in humans . Helicobacter hepaticus, an enterohepatic helicobacter in mice, is known to cause hepatocellular adenomas and carcinomas in susceptible mouse strains . In long-term chemical bioassays conducted with B6C3F(1) mice, H . hepaticus has been regarded as a confounding factor because of its tumor-promoting activity . In order to determine if woodchucks harbor a Helicobacter sp . that might play a role in potentiating hepatic inflammation or neoplasia, a study was undertaken to determine whether woodchucks' livers were infected with a Helicobacter sp . Frozen liver samples from 20 (17 WHV-infected and 3 noninfected) woodchucks, 10 with WHV-associated hepatic tumors and 10 without tumors, were cultured by microaerobic techniques and analyzed by using genus- and species-specific helicobacter PCR primers . A 1,200-bp Helicobacter sp.-specific sequence was amplified from 14 liver samples . Southern hybridization confirmed the specific identity of the PCR products . Nine of the 10 livers with tumors had positive Helicobacter sp . identified by PCR, whereas 5 of the 10 livers without tumors were positive . By use of 16S rRNA species-specific primers for H . marmotae, two additional liver samples from the nontumor group had positive PCR amplicons confirmed by Southern hybridization . A urease-, catalase-, and oxidase-positive bacterium was isolated from one liver sample from a liver tumor-positive woodchuck . By 16S rRNA analysis and biochemical and phenotypic characteristics, the organism was classified as a novel Helicobacter sp . Subsequently, four additional bacterial strains isolated from feces of cats and characterized by biochemical, phenotypic, and 16S rRNA analysis were determined to be identical to the woodchuck isolate . We propose the name Helicobacter marmotae sp . nov . for these organisms . Further studies are required to ascertain if this novel Helicobacter sp . plays a tumor promotion role in hepadnavirus-associated tumors in woodchucks or causes enterohepatic disease in cats. J Biol Chem, 2002 Sep 20, 277(38), 35133 - 9 Epub 2002 Jun 27. A novel family 8 xylanase, functional and physicochemical characterization; Collins T et al.; Xylanases are generally classified into glycosyl hydrolase families 10 and 11 and are found to frequently have an inverse relationship between their pI and molecular mass values . However, we have isolated a psychrophilic xylanase that belongs to family 8 and which has both a high pI and high molecular mass . This novel xylanase, isolated from the Antarctic bacterium Pseudoalteromonas haloplanktis, is not homologous to family 10 or 11 enzymes but has 20-30% identity with family 8 members . NMR analysis shows that this enzyme hydrolyzes with inversion of anomeric configuration, in contrast to other known xylanases which are retaining . No cellulase, chitosanase or lichenase activity was detected . It appears to be functionally similar to family 11 xylanases . It hydrolyzes xylan to principally xylotriose and xylotetraose and is most active on long chain xylo-oligosaccharides . Kinetic studies indicate that it has a large substrate binding cleft, containing at least six xylose-binding subsites . Typical psychrophilic characteristics of a high catalytic activity at low temperatures and low thermal stability are observed . An evolutionary tree of family 8 enzymes revealed the presence of six distinct clusters . Indeed classification in family 8 would suggest an (alpha/alpha)(6) fold, distinct from that of other currently known xylanases. J Bacteriol, 2002 Jul, 184(14), 3815 - 22 Natural resistance to inhibitors of the ubiquinol cytochrome c oxidoreductase of Rubrivivax gelatinosus: sequence and functional analysis of the cytochrome bc(1) complex; Ouchane S et al.; Biochemical analyses of Rubrivivax gelatinosus membranes have revealed that the cytochrome bc(1) complex is highly resistant to classical inhibitors including myxothiazol, stigmatellin, and antimycin . This is the first report of a strain exhibiting resistance to inhibitors of both catalytic Q(0) and Q(i) sites . Because the resistance to cytochrome bc(1) inhibitors is primarily related to the cytochrome b primary structure, the petABC operon encoding the subunits of the cytochrome bc(1) complex of Rubrivivax gelatinosus was sequenced . In addition to homologies to the corresponding proteins from other organisms, the deduced amino acid sequence of the cytochrome b polypeptide shows (i) an E303V substitution in the highly conserved PEWY loop involved in quinol/stigmatellin binding, (ii) other substitutions that could be involved in resistance to cytochrome bc(1) inhibitors, and (iii) 14 residues instead of 13 between the histidines in helix IV that likely serve as the second axial ligand to the b(H) and b(L) hemes, respectively . These characteristics imply different functional properties of the cytochrome bc(1) complex of this bacterium . The consequences of these structural features for the resistance to inhibitors and for the properties of R . gelatinosus cytochrome bc(1) are discussed with reference to the structure and function of the cytochrome bc(1) complexes from other organisms. Photochem Photobiol, 2002 Jun, 75(6), 605 - 12 Light- and redox-dependent thermal stability of the reaction center of the photosynthetic Bacterium rhodobacter sphaeroides; Tokaji Z et al.; Irreversible loss of the photochemical activity and damage of the pigments (bacteriochlorophyll {Bchl} monomer, Bchl dimer {P} and bacteriopheophytin) by combined treatment with intense and continuous visible light and elevated temperature have been studied in a deoxygenated solution of reaction center (RC) protein from the nonsulfur purple photosynthetic bacterium Rhodobacter sphaeroides . Both the fraction of RC in the charge-separated redox state (P+Q-, where Q is a quinone electron acceptor) and the degradation of the pigments showed saturation as a function of increasing light intensity up to 400 mW cm(-2) (488/515 nm) or 1100 microE m(-2) s(-1) (white light) . The thermal denaturation curves of the RC in the P+Q- redox state demonstrated broadening and 10-20 degrees C shift to lower temperature (after 30-90 min heat treatment) compared with those in the PQ redox state . Similar but less striking behavior was seen for RC of other redox states (P+Q and PQ-) generated either by light or by electrochemical treatment in the dark . These experiments suggest that it is not the intense light per se but the changes in the redox state of the protein that are responsible for the increased sensitivity to photo- and heat damage . The RC with a charge pair (P+Q-) is more vulnerable to elevated temperature than the RC with (P+Q or PQ-) or without (PQ) a single charge . To reveal both the thermodynamic and kinetic aspects of the denaturation, a simple three-state model of coupled reversible thermal and irreversible kinetic transitions is presented . These effects may have relevance to the heat stability of other redox proteins in bioenergetics. FEMS Microbiol Lett, 2002 Jun 4, 211(2), 129 - 32 Construction and intergeneric conjugative transfer of a pSG5-based cosmid vector from Escherichia coli to the polyisoprene rubber degrading strain Micromonospora aurantiaca W2b; Rose K et al.; A non-rubber degrading mutant of the polyisoprene rubber degrading bacterium Micromonospora aurantiaca W2b lacking the capability to form halos on latex overlay agar plates was isolated after N-methyl-N-nitro-N-nitrosoguanidine mutagenesis . A 10.3-kb shuttle cosmid vector pGM446 was constructed from the Streptomyces cloning vectors pGM160 and pOJ446 . This vector was transferred by conjugation from Escherichia coli to M . aurantiaca W2b . The frequency of formation of exconjugants with pGM446 was 3.6 x 10(-3) . This vector could be useful for shotgun cloning of genes into the non-rubber degrading mutant L1 from M . aurantiaca W2b. Int J Food Microbiol, 2002 Jul 25, 77(1-2), 135 - 45 Pasteurization of milk and the heat resistance of Mycobacterium avium subsp . paratuberculosis: a critical review of the data; Lund BM et al.; Mycobacterium avium subsp . paratuberculosis (M . paratuberculosis) causes Johne's disease in ruminants (including cattle, sheep and goats) and other animals, and may contribute to Crohn's disease in humans . This possibility, and the fact that M . paratuberculosis may be present in raw milk, make it important to ensure that the heat treatment specified for pasteurization of milk will give acceptable inactivation of this bacterium, with an adequate margin of safety . Published studies of the heat resistance of this bacterium in milk have given widely differing results . Possible reasons for these differences, and the technical problems involved in the work, are reviewed . It is concluded that there is a need (i) for the adoption of an agreed Performance Criterion for pasteurization of milk in relation to this bacterium, (ii) a need for definitive laboratory experiments to understand and determine the heat resistance of M . paratuberculosis, and (iii) a need for an assessment of whether the minimum heat treatments specified at present for pasteurization of milk (Process Criteria) will meet the Performance Criterion for M . paratuberculosis . Measures are also required to ensure that commercial processes deliver continually the specified heat treatment, and to ensure that post-pasteurization contamination is avoided. Biochem Biophys Res Commun, 2002 Jun 28, 294(5), 1138 - 43 Keratin degradation: a cooperative action of two enzymes from Stenotrophomonas sp; Yamamura S et al.; A novel keratin-degrading bacterium Stenotrophomonas sp . strain D-1, isolated from deer fur, produced two types of extracellular proteins: proteolytic and disulfide bond-reducing . The results on the biochemical properties suggest that this protease belongs to the serine protease, and the disulfide bond-reducing protein could be the disulfide reductase type . None of these enzymes showed keratinolytic activity independently . However, after mixing of the two enzymes, the keratinolytic activity was increased tremendously (more than 50-fold) over that of the protease only . This keratinolytic activity was more than 2-fold higher than that of the combination with proteinase K (also known for its high keratinolytic activity) . Since the two enzymes discovered in this study acted cooperatively and resulted in higher keratinolytic activity, a new mechanism of keratin degradation has been revealed . To our knowledge, this is the first report on the cooperative action of two enzymes resulting in the effective degradation of keratin. J Ind Microbiol Biotechnol, 2002 Feb, 28(2), 103 - 11 High-yield actinorhodin production in fed-batch culture by a Streptomyces lividans strain overexpressing the pathway-specific activator gene actll-ORF4; Bruheim P et al.; Streptomyces lividans 1,326 usually does not produce the red/blue colored polyketide actinorhodin in liquid culture even though it carries the entire actinorhodin biosynthesis gene cluster . The bacterium can be forced to produce this secondary metabolite by introducing actII-ORF4, the actinorhodin pathway-specific activator gene from Streptomyces coelicolor, on a multicopy plasmid . The production of actinorhodin by such a strain has been optimized by medium and process manipulations in fed-batch cultures . With high-yield cultivation conditions, 5 g actinorhodin/l are produced during 7 days of cultivation; or approximately 0.1 g actinorhodin/g dry weight (DW)/day in the production phase . The yield in this phase is 0.15 Cmol actinorhodin/Cmol glucose, which is in the range of 25% to 40% of the maximum theoretical yield . This high-level production mineral medium is phosphate limited . In contrast, nitrogen limitation resulted in low-level production of actinorhodin and high production of a-ketoglutaric acid . Ammonium as nitrogen source was superior to nitrate supporting an almost three times higher actinorhodin yield as well as a two times higher specific production rate . The wild-type strain lacking the multicopy plasmid did not produce actinorhodin when cultivated under any of these conditions . This work examines the actinorhodin-producing potential of the strain, as well as the necessity to improve the culture conditions to fully utilize this potential . The overexpression of biosynthetic pathway-specific activator genes seems to be a rational first step in the design of secondary metabolite overproducing strains prior to alteration of primary metabolic pathways for redirection of metabolic fluxes. Arch Microbiol, 2002 Jul, 178(1), 59 - 64 Epub 2002 Apr 30. Intracellular localization of the particulate methane monooxygenase and methanol dehydrogenase in Methylomicrobium album BG8; Brantner CA et al.; The methanotrophic bacterium Methylomicrobium album BG8 uses methane as a sole source of carbon and energy . This bacterium forms an extensive intracytoplasmic membrane . The first enzymes of the methane oxidation pathway are the membrane-bound particulate methane monooxygenase and the periplasmic methanol dehydrogenase . Immunoelectron microscopy with specific antibodies was used to localize these enzymes to the intracytoplasmic membrane. Curr Microbiol, 2002 Aug, 45(2), 123 - 7 Cloning and sequencing of an intracellular D(-)-3-hydroxybutyrate oligomer hydrolase from Acidovorax sp . strain SA1 and purification of the enzyme; Sugiyama A et al.; The gene of an intracellular D(-)-3-hydroxybutyrate oligomer hydrolase (i3HBOH) was cloned and sequenced from a poly(3-hydroxybutyrate) (PHB)-degrading bacterium, Acidovorax sp . strain SA1 . The i3HBOH gene has 876 nucleotides corresponding to the deduced sequence of 292 amino acids . In this amino acid sequence, the general lipase box sequence (G-X(1)-S-X(2)-G) was found, whose serine residue was determined to the active sites serine by site-directed mutagenesis.An i3HBOH was purified to electrophoretical homogeneity from SA1 . The molecular mass of the purified enzyme was estimated to be 32 kDa by SDS-PAGE . The N-terminal amino acid sequence of the purified enzyme corresponded to the deduced N-terminal amino acid sequence in the cloned i3HBOH gene.This is the first cloning and sequencing of an intracellular D(-)-3-hydroxybutyrate oligomer hydrolase gene to date. Environ Toxicol Chem, 2002 Jun, 21(6), 1191 - 7 Acute toxicity of triorganotin compounds: different specific effects on the energy metabolism and role of pH; Hunziker RW et al.; Triorganotin compounds exhibit several modes of toxic action on the energy metabolism in energy-transducing membranes . The inhibition of the adenosine triphosphate (ATP) synthase and the hydroxide/chloride-antiport have been extensively investigated, but debate still exists on whether further mechanisms are relevant . In this work, two possible further effects have been investigated: inhibition of the bc1 complex and the hydroxide uniport, and in addition, the overall inhibition of the ATP synthesis was investigated in chromatophores of the photosynthetic purple bacterium Rhodobacter sphaeroides at pH = 7.5 and pH = 6.1 . Experimental conditions were chosen in order to exclude the hydroxide/anion antiport as a possible effect . Inhibition of the cytochromes bc1 complex was detected, but at such high concentrations that it is not relevant for acute toxicity . Tributyltin was found to induce a decrease of the membrane potential, which can be attributed to a hydroxide uniport, whereas for triphenyltin no such activity was observed . For both compounds, inhibition of the ATP synthesis was higher at pH = 6.1 than at pH = 7.5 . Also the hydroxide uniport activity of tributyltin was higher at lower pH . The contribution of the hydroxide uniport of tributyltin to the overall inhibition of the ATP synthesis cannot be quantified; however, hydroxide uniport occurred in the same concentration range as inhibition of the ATP synthesis . For triphenyltin, inhibition of the ATP synthesis can be attributed to the inhibition of the ATP synthase . It was concluded that chromatophores of R . sphaeroides are a useful system to discriminate various effects of toxicants on the energy metabolism of a cell. Biofizika, 2002 May-Jun, 47(3), 490 - 9 {Participation of inorganic phosphates as electron donors in the primary reactions of photosynthesis in Rhodobacter sphaeroides}; Goncharova NV et al.; The formation of ATP during photophosphorylation in chromatophores from purple nonsulfur bacterium Rhodobacter sphaeroides in the presence of phenazine methosulfate and without exogenous electron carriers under constant illumination and by the action of single light flashes was studied . It was shown that the photoinduced transport of electrons to the exogenous electron acceptor depends on phosphate . It was assumed that phosphate ions are electron donors in the reaction center P870; by the action of light, P870 converts the phosphate ion HPO4(2-) into anion radical HPO4-. . In the difference EPR spectra "light minus darkness" at 77 K, an asymmetrical doublet signal with a weak low-field line was observed . The signal had a g-tensor of about 2.014 and a hyperfine coupling constant of about 2.5 mT and belongs probably to the phosphate anion radical. Microbes Infect, 2002 Jun, 4(7), 693 - 8 The putative haemobartonella that influences Plasmodium falciparum parasitaemia in squirrel monkeys is a haemotrophic mycoplasma; Neimark H et al.; Splenectomised squirrel monkeys (Saimiri sciureus) are increasingly being used as an experimental host for human malaria studies, notably for the assessment of candidate vaccines against Plasmodium falciparum blood-stage infection . Recently, S . sciureus monkeys in our primate-breeding colony were reported to be asymptomatic carriers of a putative Haemobartonella species . Patent haemobartonella infection is frequently activated following splenectomy, and may interfere with studies on the course of P . falciparum parasitaemia in these animals . Here, we show by 16S rRNA gene sequence analysis that this wall-less bacterium is not a rickettsia but, instead, is a haemotrophic mycoplasma . Haemotrophic mycoplasmas are a newly identified group of mycoplasmas that parasitise the surfaces of erythrocytes of a wide variety of vertebrate hosts. Infect Immun, 2002 Jul, 70(7), 3816 - 23 Inhibition of fusion of Chlamydia trachomatis inclusions at 32 degrees C correlates with restricted export of IncA; Fields KA et al.; Chlamydia trachomatis is an obligate intracellular bacterium that develops within a parasitophorous vacuole termed an inclusion . The inclusion is nonfusogenic with lysosomes but intercepts lipids from a host cell exocytic pathway . Initiation of chlamydial development is concurrent with modification of the inclusion membrane by a set of C . trachomatis-encoded proteins collectively designated Incs . One of these Incs, IncA, is functionally associated with the homotypic fusion of inclusions . Inclusions also do not fuse when cultures are multiply infected with C . trachomatis and cultivated at 32 degrees C . We obtained evidence linking these experimental observations by characterizing IncA localization in 32 degrees C cultures . Analysis of inclusions by light and transmission electron microscopy confirmed that HeLa cells infected with multiple C . trachomatis elementary bodies and cultivated at 32 degrees C for 24 h contained multiple, independent inclusions . Reverse transcriptase PCR and immunoblot analyses of C . trachomatis-infected HeLa cells demonstrated the presence of IncA at 24 h in 32 degrees C cultures . When parallel cultures were probed with IncA-specific antibodies in indirect immunofluorescence assays, IncA was detectable in intracellular chlamydiae but not within the inclusion membrane . In addition, analysis of purified reticulate bodies from 37 and 32 degrees C cultures showed that bacterium-associated pools of IncA are enriched in cultures grown at 32 degrees C . Microscopic observation of infected cells revealed that some vacuoles had fused by 48 h postinfection, and this finding was correlated with the detection of IncA in inclusion membranes by immunofluorescence microscopy . The data are consistent with a requirement for IncA in fusions of C . trachomatis inclusions and suggest that the effect of incubation at 32 degrees C is manifested by restricted export of IncA to the inclusion membrane. Infect Immun, 2002 Jul, 70(7), 3649 - 55 Regulation of proinflammatory cytokines in human lung epithelial cells infected with Mycoplasma pneumoniae; Yang J et al.; Mycoplasma pneumoniae is a small bacterium without a cell wall that causes tracheobronchitis and atypical pneumonia in humans . It has also been associated with chronic conditions, such as arthritis, and extrapulmonary complications, such as encephalitis . Although the interaction of mycoplasmas with respiratory epithelial cells is a critical early phase of pathogenesis, little is known about the cascade of events initiated by infection of respiratory epithelial cells by mycoplasmas . Previous studies have shown that M . pneumoniae can induce proinflammatory cytokines in several different study systems including cultured murine and human monocytes . In this study, we demonstrate that M . pneumoniae infection also induces proinflammatory cytokine expression in A549 human lung carcinoma cells . Infection of A549 cells resulted in increased levels of interleukin-8 (IL-8) and tumor necrosis factor alpha mRNA, and both proteins were secreted into culture medium . IL-1 beta mRNA also increased after infection and IL-1 beta protein was synthesized, but it remained intracellular . In contrast, levels of IL-6 and gamma interferon mRNA and protein remained unchanged or undetectable . Using protease digestion and antibody blocking methods, we found that M . pneumoniae cytoadherence is important for the induction of cytokines . On the other hand, while M . pneumoniae protein synthesis and DNA synthesis do not appear to be prerequisites for the induction of cytokine gene expression, A549 cellular de novo protein synthesis is responsible for the increased cytokine protein levels . These results suggest a novel role for lung epithelial cells in the pathogenesis of M . pneumoniae infection and provide a better understanding of M . pneumoniae pathology at the cellular level. Infect Immun, 2002 Jul, 70(7), 3637 - 48 Macrophage-induced genes of Legionella pneumophila: protection from reactive intermediates and solute imbalance during intracellular growth; Rankin S et al.; A promoter-probe strategy was devised to identify genes specifically expressed by Legionella pneumophila during growth within the macrophage . Random fragments from the L . pneumophila chromosome were inserted upstream of a promoterless phage T4 td gene, and fragments that led to complementation of thymine auxotrophy during intracellular growth of the bacterium were identified . Two different selection strategies were employed to eliminate promoters that were also active during extracellular growth of the bacterium . Some of these genes were identified independently by using both of the selection strategies . The factors identified include orthologs of efflux-mediated resistance determinants and transporters, a transporter involved in protection from osmotic stress, a stress response GTP-binding protein, a response regulator, a sensor kinase, and two systems that increase the reducing potential of the bacterium, one of which encodes the L . pneumophila ortholog of ahpC . Five of the clones analyzed here were fusions to promoters that were closely linked to genes encoding three-component chemiosmotic efflux pumps that export heavy metals or toxic organic compounds . Analysis of ahpC gene expression indicates that levels increased at least sevenfold during intracellular growth of the bacterium . Inactivation of several of the genes at their chromosomal loci had no effect on the intracellular growth rate of L . pneumophila in cultured macrophages . This suggests that a number of genes with increased expression during intracellular growth may be part of redundant systems that allow survival and growth under the conditions encountered within host cells. J Med Entomol, 2002 May, 39(3), 534 - 40 Rickettsiella-like bacteria in Ixodes woodi (Acari: Ixodidae); Kurtti TJ et al.; We examined a parthenogenetic strain of the hard tick Ixodes woodi Bishopp for the presence of endosymbiotic bacteria . Electron microscopic examination revealed the ovarian tissues and Malpighian tubules were infected with pleomorphic bacteria . Two basic types were observed: a larger granular cell and a smaller condensed cell . Cloning and sequence analysis of polymerase chain reaction (PCR) amplified 16S rRNA gene yielded a single sequence from bacteria present in I . woodi tissues . Phylogenetic analysis of the nearly complete 16S rDNA indicated that the ticks were infected with an endosymbiont belonging to the gamma subdivision of the Proteobacteria . It clustered with the insect pathogenic species Rickettsiellagrylli (Vago and Martoja 1963) and the animal pathogen Coxiella burnetii (Derrick 1939) Philip 1948 . Our results suggest that the I . woodi females harbored a single endosymbiotic bacterium related to selected Rickettsiella species and to C burnetii. Naturwissenschaften, 2002 Apr, 89(4), 167 - 70 Feminization of genetic males by a symbiotic bacterium in a butterfly, Eurema hecabe (Lepidoptera: Pieridae); Hiroki M et al.; Wolbachia are symbiotic bacteria found in many arthropods and filarian nematodes . They often manipulate the reproduction of host arthropods . In the present study, female-biased sex-ratio distortion in the butterfly Eurema hecabe was investigated . Breeding experiments showed that this distorted sex ratio is maternally inherited . When treated with tetracycline, adult females of the thelygenic line produced male progeny only . After PCR using Wolbachia-specific primers for the ftsZ gene a positive result was seen in the thelygenic females, but not in male progeny from tetracycline-treated females, or individuals from a Tokyo population with normal sex ratio and reproduction . Cytological observations showed that thelygenic females lack the sex chromatin body (W chromosome) . The results strongly suggest that the sex-ratio distortion in E . hecabe is due to feminization of genetic males by Wolbachia. Biochem Biophys Res Commun, 2002 Jun 14, 294(3), 567 - 73 Evidence for a wide occurrence of proton-translocating pyrophosphatase genes in parasitic and free-living protozoa; Perez-Castineira JR et al.; Proton-translocating inorganic pyrophosphatases (H(+)-PPase, EC 3.6.1.1) are integral membrane proteins that have been extensively studied in higher plants, the photosynthetic bacterium Rhodospirillum rubrum and, more recently, in some human pathogenic protozoa . By using a PCR-based approach, fragments of genes coding for H(+)-PPases in a number of protists, both free-living and parasites of animals and plants, that belong to diverse taxonomic groups (trypanosomatids, ciliates, apicomplexans, euglenoids, amoeboid mycetozoa, heterokonts) have been isolated . The experimental procedure involved the use of degenerate oligonucleotides designed from protein domains conserved in H(+)-PPases from plants and bacteria . The PCR-amplified DNA fragments exhibited the characteristic genomic structure and codon usage of the corresponding protozoan group . Paralogous genes were found in some species suggesting the occurrence of protein isoforms . These results indicate that H(+)-PPases are more widely distributed among protozoa than previously thought. J Mol Biol, 2002 May 10, 318(4), 1085 - 95 Assembly of light-harvesting bacteriochlorophyll in a model transmembrane helix in its natural environment; Braun P et al.; The transmembrane, bacteriochlorophyll-binding region of a bacterial light-harvesting complex, (LH2-alpha from the photosynthetic bacterium Rhodobacter sphaeroides) was redesigned and overexpressed in a mutant of Rb . sphaeroides lacking LH2 . Bacteriochlorophyll served as internal probe for the fitness of this new region for the assembly and energy transfer function of the LH2 complex . The ability to absorb and transfer light energy is practically undisturbed by the exchange of the transmembrane segment, valine -7 to threonine +6, of LH2-alpha with a 14 residue Ala-Leu sequence . This stretch makes up the residues of the transmembrane helix that are in close contact (< or =4.5 A) with the bacteriochlorophyll molecules that are coordinated through His of both the alpha and beta-subunits . In this Ala-Leu stretch, neither alpha-His0, which binds the bacteriochlorophyll, nor the adjacent alpha-Ile-1, were replaced . Novel LH2 complexes composed of LH2-alpha with a model transmembrane sequence and a normal LH2-beta are assembled in vivo into a complex, the biochemical and spectroscopic properties of which closely resemble the native one . In contrast, the additional insertion of four residues just outside the C-terminal end of the model transmembrane helix leads to complete loss of functional antenna complex . The results suggest that light energy can be harvested and transferred efficiently by bacteriochlorophyll molecules attached to only few key residues distributed over the polypeptide, while residues at the bacteriochlorophyll-helix interface seem to be largely dispensable for the functional assembly of this membrane protein complex . This novel antenna with a simplified transmembrane domain and a built-in probe for assembly and function provides a powerful model system for investigation of the factors that contribute to the assembly of chromophores in membrane-embedded proteins . (c) 2002 Elsevier Science Ltd. Int J Syst Evol Microbiol, 2002 May, 52(Pt 3), 983 - 6 Anaeroglobus geminatus gen . nov., sp . nov., a novel member of the family Veillonellaceae; Carlier JP et al.; A hitherto unknown anaerobic coccus isolated from a post-operative fluid collection was characterized by phenotypic and phylogenetic methods . 16S rDNA sequence analysis revealed an affiliation of this isolate to the family Veillonellaceae . Also, a high level of sequence similarity was observed to some oral clone sequences of Megasphaera spp . contained in the GenBank database under designations BB166, CS025 and BS073 . These clones and the unknown bacterium form a well-separated phylogenetic branch that may represent a novel lineage within the family Veillonellaceae . Based on phenotypic and phylogenetic evidence, a new genus, Anaeroglobus gen . nov., is proposed for the unknown bacterium, with one species, Anaeroglobus geminatus gen . nov., sp . nov . The type strain of Anaeroglobus geminatus is strain AIP 313.00T (= CIP 106856T = CCUG 44773T) . It is also suggested that the oral clones BB166, CS025 and BS073 belong to the genus Anaeroglobus. Int J Syst Evol Microbiol, 2002 May, 52(Pt 3), 831 - 4 Weissella soli sp . nov., a lactic acid bacterium isolated from soil; Magnusson J et al.; Phylogenetic analysis of the 16S rRNA gene of bacterial isolates from garden soil showed relatedness to Weissella kandleri and Weissella confusa . However, the sequences had notable differences, and DNA-DNA hybridizations confirmed that the isolates are separate from these two species . The isolates could be further distinguished from all previously described Weissella species by electrophoretic analysis of whole-cell proteins, as well as by the results from different biochemical tests . The name Weissella soli is proposed for the new species, the type strain being Mi268T (= LMG 20113T = DSM 14420T). Int J Syst Evol Microbiol, 2002 May, 52(Pt 3), 813 - 8 Kozakia baliensis gen . nov., sp . nov., a novel acetic acid bacterium in the alpha-proteobacteria; Lisdiyanti P et al.; Four bacterial strains were isolated from palm brown sugar and ragi collected in Bali and Yogyakarta, Indonesia, by an enrichment culture approach for acetic acid bacteria . Phylogenetic analysis based on 16S rRNA gene sequences showed that the four isolates constituted a cluster separate from the genera Acetobacter, Gluconobacter, Acidomonas, Gluconacetobacter and Asaia with a high bootstrap value in a phylogenetic tree . The isolates had high values of DNA-DNA similarity (78-100%) between one another and low values of the similarity (7-25%) to the type strains of Acetobacter aceti, Gluconobacter oxydans, Gluconacetobacter liquefaciens and Asaia bogorensis . The DNA base composition of the isolates ranged from 56.8 to 57.2 mol% G+C with a range of 0-4 mol% . The major quinone was Q-10 . The isolates oxidized acetate and lactate to carbon dioxide and water, but the activity was weak, as with strains of Asaia bogorensis . The isolates differed from Asaia bogorensis strains in phenotypic characteristics . The name Kozakia baliensis gen . nov., sp . nov., is proposed for the four isolates . Strain Yo-3T (= NRIC 0488T = JCM 11301T = IFO 16664T = DSM 14400T) was isolated from palm brown sugar collected in Bali, Indonesia, and was designated as the type strain. Int J Syst Evol Microbiol, 2002 May, 52(Pt 3), 1017 - 21 Arthrobacter roseus sp . nov., a psychrophilic bacterium isolated from an antarctic cyanobacterial mat sample; Reddy GS et al.; Strain CMS 90rT, a red-pigmented bacterium, was isolated from a cyanobacterial mat sample from a pond located in McMurdo, Antarctica . Based on its chemotaxonomic and phylogenetic properties, strain CMS 90r(T) was identified as a member of group I of Arthrobacter . It shared 16S rDNA similarity of 98% with Arthrobacter oxydans ATCC 14358T and Arthrobacter polychromogenes ATCC 15216T, while DNA-DNA similarities determined for these three organisms were less than 70% . It also differed from all 17 reported Arthrobacter species with A3alpha-variant peptidoglycan in that it possessed a unique peptidoglycan (Lys-Gly-Ala3) and contained galactose, glucose, ribose and rhamnose as cell-wall sugars . These data and the presence of diagnostic phenotypic traits support the description of CMS 90r(T) as a novel species of Arthrobacter, for which the name Arthrobacter roseus sp . nov . is proposed . The type strain is strain CMS 90r(T) (= MTCC 3712T = DSM 14508T). Biotechnol Prog, 2002 May-Jun, 18(3), 652 - 6 Expression of double Vitreoscilla hemoglobin enhances growth and alters ribosome and tRNA levels in Escherichia coli; Roos V et al.; In several organisms, expression of a gene encoding dimeric hemoglobin (VHb) from the obligate aerobic bacterium Vitreoscilla stercoraria has been shown to increase microaerobic cell growth and enhance oxygen-dependent cell metabolism . In an attempt to further improve these effects of VHb, a gene encoding two vhb genes connected by a short linker of six base pairs was constructed and expressed in Escherichia coli(double VHb) . Escherichia coli cells expressing double VHb reached a cell density 19% higher than that of cells expressing native VHb . The protein production per cell remained constant since the increase in cell growth was accompanied by an increase in protein content by 16% . Investigation of ribosome and tRNA content revealed that cells expressing double VHb reached their maximal capacity of protein synthesis later during cultivation than cells expressing native VHb, and furthermore they reached considerably higher levels of ribosome and tRNA compared to that of the VHb-expressing cells. J Mol Biol, 2002 May 31, 319(2), 501 - 15 X-ray structure determination of the cytochrome c2: reaction center electron transfer complex from Rhodobacter sphaeroides; Axelrod HL et al.; In the photosynthetic bacterium Rhodobacter sphaeroides, a water soluble cytochrome c2 (cyt c2) is the electron donor to the reaction center (RC), the membrane-bound pigment-protein complex that is the site of the primary light-induced electron transfer . To determine the interactions important for docking and electron transfer within the transiently bound complex of the two proteins, RC and cyt c2 were co-crystallized in two monoclinic crystal forms . Cyt c2 reduces the photo-oxidized RC donor (D+), a bacteriochlorophyll dimer, in the co-crystals in approximately 0.9 micros, which is the same time as measured in solution . This provides strong evidence that the structure of the complex in the region of electron transfer is the same in the crystal and in solution . X-ray diffraction data were collected from co-crystals to a maximum resolution of 2.40 A and refined to an R-factor of 22% (R(free)=26%) . The structure shows the cyt c2 to be positioned at the center of the periplasmic surface of the RC, with the heme edge located above the bacteriochlorophyll dimer . The distance between the closest atoms of the two cofactors is 8.4 A . The side-chain of Tyr L162 makes van der Waals contacts with both cofactors along the shortest intermolecular electron transfer pathway . The binding interface can be divided into two domains: (i) A short-range interaction domain that includes Tyr L162, and groups exhibiting non-polar interactions, hydrogen bonding, and a cation-pi interaction . This domain contributes to the strength and specificity of cyt c2 binding . (ii) A long-range, electrostatic interaction domain that contains solvated complementary charges on the RC and cyt c2 . This domain, in addition to contributing to the binding, may help steer the unbound proteins toward the right conformation . Expert Rev Mol Diagn, 2002 May, 2(3), 257 - 66 Moving to nucleic acid-based detection of genital Chlamydia trachomatis; Tong CY et al.; Laboratory diagnosis of the bacterium Chlamydia trachomatis has gone through a complete phase of evolution since it was first identified as a significant cause of sexually transmitted infection . As a fragile, obligatory intracellular organism, it was initially only grown in eggs . Subsequently, diagnosis relied on culture in continuous cell lines . To address the limitations of culture, immunological methods were developed and direct antigen detection using enzyme immunoassay and immunofluorescence flourished . With the advent of molecular technologies, nucleic acid-based amplification techniques became the methods of choice, offering improved standard of care for diagnosis and opening up the possibility of screening using noninvasive, patient-acceptable specimens . In this article, the various currently available molecular methods are examined, some of the existing problems discussed and a view on what we think might happen in the next 5 years to the technology and requirement in diagnosis and screening is given. Proc Natl Acad Sci U S A, 2002 Jun 11, 99(12), 7917 - 21 Epub 2002 Jun 04. The RecA proteins of Deinococcus radiodurans and Escherichia coli promote DNA strand exchange via inverse pathways; Kim JI et al.; The RecA protein of Escherichia coli, and all filament-forming homologues identified to date, promote DNA strand exchange by a common, ordered pathway . A filament is first formed on single-stranded DNA, followed by uptake of the duplex substrate . These proteins are thereby targeted to single-strand gaps and tails where recombinational DNA repair is required . The observed course of DNA strand exchange promoted by the RecA protein from the extremely radioresistant bacterium Deinococcus radiodurans is the exact inverse of this established pathway . This reaction lies at the heart of a remarkably efficient system for the repair of DNA damage. Microbes Infect, 2002 May, 4(6), 591 - 8 Mouse resident peritoneal macrophages partially control in vitro infection with Coxiella burnetii phase II; Zamboni DS et al.; Coxiella burnetii, the agent of Q fever in man and of coxiellosis in other species, is a small, dimorphic, obligate intracellular bacterium, sheltered within large, acidified, and hydrolase-rich phagosomes . Although several primary and established cell lines, macrophage-like cells, and primary macrophages from other species have been infected with C . burnetii, the infection of mouse primary macrophages has not been sufficiently characterized . In this report quantification of DAPI (4', 6-diamino-2-phenylindole) fluorescence images acquired by confocal microscopy, and transmission electron microscopy were used to compare the infection of three mouse-derived cells, L929 fibroblasts, J774 macrophage-like cells, and resident peritoneal macrophages, with a phase II clone of C . burnetii known to be non-virulent for mammals . Infected peritoneal phagocytes differed from L929 or J774 cells in that: (a) large vacuoles took longer to appear (3-5 d instead of 2), and were only found in a subset (20-30%) of macrophages, as opposed to in more than 70% of the other cells; (b) total and vacuole-associated relative bacterial loads in L929 and J774 cells were several-fold higher than in peritoneal macrophages; (c) estimated doubling times of the bacteria were about 68 h in the primary macrophages, 18 h in J774 and 22 h in L929 cells . Thus, mouse resident peritoneal macrophages control both the formation of the large vacuoles and the intracellular proliferation of C . burnetii phase II. Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai), 2001, 33(5), 519 - 524 Expression of Choline Oxidase Gene (codA) Enhances Salt Tolerance of the Tobacco; He PM et al.; The codA gene for choline oxidase, which converts choline into betaine . This enzyme, cloned from a soil bacterium Arthrobactor globiformis, has been transferred and expressed in tobacco by the Agrobatcterium-method transformation through the binary plasmid pGAH/codA . The pGAH/codA carried with Km(R) and Hyg(R),and coding sequence for a transit peptide from Rubisco small subunit gene (rbcS) was inserted between 35 S promoter and codA, so that the COD could be introduced into the chloroplast by this transit peptide . The transformed plants were screened on the medium containing the Km and Hyg . PCR, Western and gold immunolocalization tests showed that the codA gene has integrated into the tobacco DNA genome and its protein was expressed and the mature peptide has gone into the chloroplasts by the transit peptide . The results of salt-tolerance measuring for transgenic plants showed that the transgenic plants were more tolerance to the salt than the control plants . The young transgenic plants (1.0--1.5 cm) could survive at 400 mmol/L NaCl MS medium for more than 30 days . From them the higher tolerance plant T4-400 was obtained, which could grow at the 300 mmol/L NaCl MS medium well . The transgenic plants (6--8cm) could grow normally at the 400 mmol/L NaCl MS medium while wild plants failed to do so . So the transferred plant with codA enhanced its tolerance to the salt stress. Appl Environ Microbiol, 2002 Jun, 68(6), 2781 - 93 Genetic complementation of an outer membrane cytochrome omcB mutant of Shewanella putrefaciens MR-1 requires omcB plus downstream DNA; Myers JM et al.; Anaerobically grown cells of the metal-reducing bacterium Shewanella putrefaciens MR-1 contain multiple outer membrane (OM) cytochromes . A gene replacement mutant (strain OMCB1) lacking the OM cytochrome OmcB is markedly deficient in the reduction of MnO2 and exhibits reduced rates of Fe(III) reduction . The levels of other OM cytochromes are also decreased in OMCB1 . Complementation of OMCB1 with wild-type omcB did not restore any of these defects . However, a 21-kb genomic fragment from MR-1, which included omcB and 19 kb of downstream DNA, fully restored MnO2 and Fe(III) reduction and the full complement of OM cytochromes to OMCB1 . A 14.7-kb DNA fragment, including omcB and 12 kb of downstream DNA, provided only a modest increase in MnO2 reduction and OM cytochrome content, but it fully restored Fe(III) citrate reduction and partially restored FeOOH reduction . While omcB mRNA was readily detected in this complement, the OmcB protein was not detected in any cellular compartment . The restoration of Fe(III) reduction despite the absence of OmcB suggests that OmcB itself is not required for Fe(III) reduction . Another OM cytochrome, OmcA, was mislocalized to the cytoplasmic membrane of OMCB1 . Only the 21-kb genomic fragment was able to restore proper localization of OmcA to the OM . This 21-kb fragment does not contain omcA, but it does contain several open reading frames (ORFs) downstream from omcB . The most downstream of these ORFs (altA) encodes a putative AraC-like transcriptional regulator . However, a gene replacement mutant of altA resembled the wild type with respect to MnO2 reduction, OM cytochrome content, and the localization of OmcA and OmcB to the OM . Since OMCB1 continues to express genes immediately downstream from omcB, the lack of expression of this downstream DNA does not explain its phenotype or the need for the large complementing fragment . The results suggest that the DNA downstream of omcB must be present in cis in order to restore Fe(III) reduction, MnO2 reduction, OM cytochrome content, and the localization of OmcA and OmcB to the OM. Nature, 2002 May 30, 417(6888), 533 - 5 Quantum control of energy flow in light harvesting; Herek JL et al.; Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes . The adaptive shaping of laser pulses is a particularly powerful tool in this context: experimental output as feedback in an iterative learning loop refines the applied laser field to render it best suited to constraints set by the experimenter . This approach has been experimentally implemented to control a variety of processes, but the extent to which coherent excitation can also be used to direct the dynamics of complex molecular systems in a condensed-phase environment remains unclear . Here we report feedback-optimized coherent control over the energy-flow pathways in the light-harvesting antenna complex LH2 from Rhodopseudomonas acidophila, a photosynthetic purple bacterium . We show that phases imprinted by the light field mediate the branching ratio of energy transfer between intra- and intermolecular channels in the complex's donor acceptor system . This result illustrates that molecular complexity need not prevent coherent control, which can thus be extended to probe and affect biological functions. Biosci Biotechnol Biochem, 2002 Apr, 66(4), 866 - 8 Response of the ice-nucleating bacterium Pantoea ananas KUIN-3 during cold acclimation; Koda N et al.; The ice-nucleating bacterium Pantoea ananas KUIN-3 accumulated glucose in cells following a shift in temperature (10 degrees C) from the optimum growth temperature (30 degrees C) . This accumulation might be caused by the activation of glucose-6-phosphatase . Although this strain after culturing at 30 degrees C was harmed by freezing, the cryotolerance of this strain was reached about 80% after cold acclimation at 10 degrees C. Biosci Biotechnol Biochem, 2002 Apr, 66(4), 737 - 42 Heterogeneity of dehydrogenases of Stenotrophomonas maltophilia showing dye-linked activity with polypropylene glycols; Tachibana S et al.; Distinct enzyme activities were found in extracts from Stenotrophomonas maltophilia showing dye-linked oxidation of polypropylene glycols . The activities were induced when polypropylene glycols served as sole carbon and energy sources for the bacterium . In the logarithmic phase, most of the enzyme activities (88%) were found in the cytoplasm . In the stationary phase, more than half of the activities (54%) were found on the membrane, but significant activities were also distributed in the periplasm (34%) and the cytoplasm (12%) . The enzyme activities differed from each other in their localization, time of induction in the growth cycle, specificity toward electron acceptor, and electrophoresis mobility. Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai), 2001, 33(6), 607 - 614 Isolation and Analysis of hupR Gene Required for the Expression of Hydrogenase in Rhodobacter sphaeroides; Xu DQ et al.; Cosmid 1 containing the hup genes isolated from the photosynthetic bacterium Rhodobacter sphaeroides was studied . The hupR gene from cosmid 1 was cloned and sequenced (EMBL accession number AJ243734) . It encoded a 54.031 kD protein homologous to transcriptional regulators belonging to the superfamily of two-component regulatory systems . The HupR protein was overexpressed in Escherichia coli in the form of His6-tagged HupR . The cloned hupR gene could restore hydrogenase activity in R.sphaeroides hupR mutants and activate hupSL gene transcription. J Mol Model (Online), 2002 Feb, 8(2), 58 - 64 Homology modeling reveals the structural background of the striking difference in thermal stability between two related {NiFe}hydrogenases; Szilagyi A et al.; Hydrogenases are redox metalloenzymes in bacteria that catalyze the uptake or production of molecular hydrogen . Two homologous nickel-iron hydrogenases, HupSL and HydSL from the photosynthetic purple sulfur bacterium Thiocapsa roseopersicina, differ substantially in their thermal stabilities despite the high sequence similarity between them . The optimum temperature of HydSL activity is estimated to be at least 50 degrees C higher than that of HupSL . In this work, homology models of both proteins were constructed and analyzed for a number of structural properties . The comparison of the models reveals that the higher stability of HydSL can be attributed to increased inter-subunit electrostatic interactions: the homology models reliably predict that HydSL contains at least five more inter-subunit ion pairs than HupSL . The subunit interface of HydSL is more polar than that of HupSL, and it contains a few extra inter-subunit hydrogen bonds . A more optimized cavity system and amino acid replacements resulting in increased conformational rigidity may also contribute to the higher stability of HydSL . The results are in accord with the general observation that with increasing temperature, the role of electrostatic interactions in protein stability increases . Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00894-001-0071-8. J Bacteriol, 2002 Jun, 184(12), 3396 - 400 Gas channels for NH(3): proteins from hyperthermophiles complement an Escherichia coli mutant; Soupene E et al.; Ammonium transport (Amt) proteins appear to be bidirectional channels for NH(3) . The amt genes of the hyperthermophiles Aquifex aeolicus and Methanococcus jannaschii complement enteric amtB mutants for growth at 25 nM NH(3) at 37 degrees C . To our knowledge, Amt proteins are the first hyperthermophilic membrane transport proteins shown to be active in a mesophilic bacterium . Despite low expression levels, His-tagged Aquifex Amt could be purified by heating and nickel chelate affinity chromatography . It could be studied genetically in Escherichia coli. J Bacteriol, 2002 Jun, 184(12), 3368 - 76 Chlorobium tepidum mutant lacking bacteriochlorophyll c made by inactivation of the bchK gene, encoding bacteriochlorophyll c synthase; Frigaard NU et al.; The gene encoding bacteriochlorophyll (BChl) c synthase was identified by insertional inactivation in the photosynthetic green sulfur bacterium Chlorobium tepidum and was named bchK . The bchK mutant of C . tepidum was rusty-orange in color and completely lacked BChl c . Because of the absence of the BChl c antenna, the mutant grew about seven times slower than the wild type at light intensities that were limiting to the wild type (< 90 micromol m(-2) s(-1)) . Various pheophorbides, which probably represent precursors of BChl c which had lost magnesium, accumulated in the mutant cells . A small fraction of these pheophorbides were apparently esterified by the remaining chlorophyll (Chl) a and BChl a synthases in cells . The amounts of BChl a, Chl a, isoprenoid quinones, carotenoids, Fenna-Matthews-Olson protein, and chlorosome envelope protein CsmA were not significantly altered on a cellular basis in the mutant compared to in the wild type . This suggests that the BChl a antennae, photosynthetic reaction centers, and remaining chlorosome components were essentially unaffected in the mutant . Electron microscopy of thin sections revealed that the mutant lacked normal chlorosomes . However, a fraction containing vestigial chlorosomes, denoted "carotenosomes," was partly purified by density centrifugation; these structures contained carotenoids, isoprenoid quinones, and a 798-nm-absorbing BChl a species that is probably protein associated . Because of the absence of the strong BChl c absorption found in the wild type, the bchK mutant should prove valuable for future analyses of the photosynthetic reaction center and of the roles of BChl a in photosynthesis in green bacteria . An evolutionary implication of our findings is that the photosynthetic ancestor of green sulfur bacteria could have evolved without chlorosomes and BChl c and instead used only BChl a-containing proteins as the major light-harvesting antennae. Proc R Soc Lond B Biol Sci, 2002 May 7, 269(1494), 931 - 6 Antagonistic coevolution between a bacterium and a bacteriophage; Buckling A et al.; Antagonistic coevolution between hosts and parasites is believed to play a pivotal role in host and parasite population dynamics, the evolutionary maintenance of sex and the evolution of parasite virulence . Furthermore, antagonistic coevolution is believed to be responsible for rapid differentiation of both hosts and parasites between geographically structured populations . Yet empirical evidence for host-parasite antagonistic coevolution, and its impact on between-population genetic divergence, is limited . Here we demonstrate a long-term arms race between the infectivity of a viral parasite (bacteriophage; phage) and the resistance of its bacterial host . Coevolution was largely driven by directional selection, with hosts becoming resistant to a wider range of parasite genotypes and parasites infective to a wider range of host genotypes . Coevolution followed divergent trajectories between replicate communities despite establishment with isogenic bacteria and phage, and resulted in bacteria adapted to their own, compared with other, phage populations. Cell Microbiol, 2002 May, 4(5), 273 - 83 Determination of the physical environment within the Chlamydia trachomatis inclusion using ion-selective ratiometric probes; Grieshaber S et al.; Chlamydia trachomatis is an obligate intracellular bacterium with a biphasic life cycle that takes place entirely within a membrane-bound vacuole termed an inclusion . The chlamydial inclusion is non-fusogenic with endosomal or lysosomal compartments but intersects a pathway involved in transport of sphingomyelin from the Golgi apparatus to the plasma membrane . The physical conditions within the mature chlamydial inclusion are unknown . We used ratiometric imaging with membrane-permeant, ion-selective fluorescent dyes for microanalyis of the physical environment within the inclusion . Determination of H+, Na+, K+ and Ca(2+) concentrations using CFDA (carboxy fluorescein diacetate) or BCECF-AM (2',7'-bis (2-carboxyethyl)-5,6-carboxyfluorescein acetoxymethyl ester, SBFI-AM, PBFI-AM and fura-PE3-acetomethoxyester (Fura-PE3-AM), respectively, indicated that all ions assayed within the lumenal space of the inclusion approximated the concentrations within the cytoplasm . Stimulation of purinergic receptors by addition of extracellular ATP triggered a dynamic Ca(2+) response that occurred simultaneously within the cytoplasm and interior of the inclusion . The chlamydial inclusion thus appears to be freely permeable to cytoplasmic ions . These results have implications for nutrient acquisition by chlamydiae and may contribute to the non-fusogenicity of the inclusion with endocytic compartments. Environ Sci Technol, 2002 May 1, 36(9), 1971 - 9 Baseline toxicity (narcosis) of organic chemicals determined by in vitro membrane potential measurements in energy-transducing membranes; Escher BI et al.; Baseline toxicity of a selection of industrial chemicals and pharmaceuticals is determined experimentally with a new in vitro test system (Kinspec) using membrane vesicles isolated from a photosynthetic bacterium, Rhodobacter sphaeroides . This test system is selective and more sensitive than other mechanistic test systems for baseline toxicity . The only concomitantly determined mechanism is uncoupling, which can be distinguished from baseline toxicity by pH-dependent measurements . Because the tests system contains only the target site for baseline toxicants, the biological membrane, effective target site concentrations can be directly related to observed effects by combining the in vitro test with membrane-water partition experiments . No differences were found between the effective membrane concentrations of nonpolar and polar compounds, confirming the earlier hypothesis that differences in lethal body burdens are primarily caused by unequal distribution of the compounds between target and nontarget lipids and not by different mechanisms . A selection of pharmaceuticals with various specific modes of toxic action exhibited the same constant effective membrane concentrations as found for pure baseline toxicants . In mixtures of four to six components, the pharmaceuticals were concentration-additive with each other and with the pure baseline toxicants . A potential application of the proposed test system lies, therefore, in assessing the cumulative baseline toxicity in complex environmental mixtures. Environ Sci Technol, 2002 May 1, 36(9), 1939 - 46 Enhancement of biological reduction of hematite by electron shuttling and Fe(II) complexation; Royer RA et al.; Natural organic matter (NOM) enhancement of the biological reduction of hematite (alpha-Fe2O3) by the dissimilatory iron-reducing bacterium Shewanella putrefaciens strain CN32 was investigated under nongrowth conditions designed to minimize precipitation of biogenic Fe(II) . Hydrogen served as the electron donor . Anthraquinone-2,6-disulfonate (AQDS), methyl viologen, and methylene blue {quinones with an Ew0 (pH 7) of 0.011 V or less}, ferrozine {a strong Fe(II) complexing agent}, and characterized aquatic NOM (Georgetown NOM or Suwannee River fulvic acid) enhanced bioreduction in 5-day experiments whereas 1,4-benzoquinone (Ew0 value = 0.280 V) did not . A linear relationship existed between total Fe(II) produced and concentrations of ferrozine or NOM but not quinones, except in the case of methylene blue . Such a linear relationship between Fe(II) and methylene blue concentrations could be due to the systems being far undersaturated with respect to methylene blue or the loss of the thermodynamic driving force . A constant concentration of AQDS and variable concentrations of ferrozine produced a linear relationship between total Fe(II) produced and the concentration of ferrozine . Enhancement effects of both AQDS and ferrozine were additive . NOM may serve as both an electron shuttle and an Fe(II) complexant; however, the concentration dependence of hematite reduction with NOM was more similar to ferrozine than quinones . NOM likely enhances hematite reduction initially by electron shuttling and then further by Fe(II) complexation, which prevents Fe(II) sorption to hematite and cell surfaces. Microb Ecol, 2001 Dec, 42(4), 562 - 571 Loss of Estuarine Bacteria by Viral Infection and Predation in Microcosm Conditions; Almeida MA et al.; The bacterioplankton density in Ria de Aveiro, a shallow estuarine ecosystem, varied in the broad range of 1.9-10.6 x 109 cells L-1 . The range of values was about 2 times higher in brackish water than in marine water . At high tide bacterial abundance was 2-3 times lower than at low tide . The overall variation in virioplankton was in the range of 2.4-25.0 x 1010 particles L-1 . Brackish water was about 2 times richer in viral particles than the marine water . Near low tide the virioplankton was 2-3 times higher that at high tide . Viral density followed the pattern of bacterial abundance (it explained 40% of virioplankton variation) . The viruses to bacterium ratio varied, throughout tidal cycles, by a factor of about 10 establishing the range 4.7-55.6 (average 17.6) . This ratio was rather similar in the two estuarine zones . We compared the effects of infection and predation on the control of bacterioplankton size in the two zones of the estuary . The approach to this question was conducted in experimental microcosms, set up in six combinations of plankton variables affecting the presence/absence of predators, virus-to-bacterium ratio (10-fold increase), virus-to-bacterium distance (2.2-fold increase), and bacterial growth rate . The results showed that predation was similar, in a percent basis, in marine (69%) and brackish water (73%) . Viral infection was, however, higher in brackish water (59%) than in the marine water (36%) . We conclude that the bacterioplankton along the salinity gradient evolves under biological pressures that are in different balance in the marine and brackish water zones . The effect of viral lysis on bacterial communities with enhanced growth (after yeast extract addition) was masked even when the initial ratio was 10-fold greater than in the natural samples . The high density of the virioplankton did not preclude the large and rapid increase in bacterial density . We suggest that the dynamics of the equilibrium between bacteria and viruses in the environment is driven to higher numerical levels during periods of intensive bacterial growth . On the contrary, at low bacterial growth rates the temporarily increased virus-to-bacterium ratio may drive the equilibrium to its lowest levels. J Comput Biol, 2002, 9(2), 261 - 76 Predicting the beta-helix fold from protein sequence data; Cowen L et al.; A method is presented that uses beta-strand interactions to predict the parallel right-handed beta-helix super-secondary structural motif in protein sequences . A program called BetaWrap implements this method and is shown to score known beta-helices above non-beta-helices in the Protein Data Bank in cross-validation . It is demonstrated that BetaWrap learns each of the seven known SCOP beta-helix families, when trained primarily on beta-structures that are not beta-helices, together with structural features of known beta-helices from outside the family . BetaWrap also predicts many bacterial proteins of unknown structure to be beta-helices; in particular, these proteins serve as virulence factors, adhesins, and toxins in bacterial pathogenesis and include cell surface proteins from Chlamydia and the intestinal bacterium Helicobacter pylori . The computational method used here may generalize to other beta-structures for which strand topology and profiles of residue accessibility are well conserved. Protein Sci, 2002 Jun, 11(6), 1309 - 19 Electrostatic properties of the anion selective porin Omp32 from Delftia acidovorans and of the arginine cluster of bacterial porins; Zachariae U et al.; The functional properties of the anion-selective porin Omp32 from the bacterium Delftia acidovorans, formerly Comamonas acidovorans, are determined by the particularly narrow channel constriction and the electrostatic field inside and outside the pore . A cluster of arginines (Arg 38, Arg 75, and Arg 133) determines the electrostatic field close to the constriction zone . Stacked amino acids carrying charges are prone to drastic pK(a) shifts . However, optimized calculations of the titration behavior of charged groups, based on the finite-difference Poisson-Boltzmann technique, suggest that all the arginines are charged at physiological pH . Protonation of the clustered arginines is stabilized by one buried glutamate residue (Glu 58), which is strongly interacting with Arg 75 and Arg 38 . This functional arrangement of three charged amino acid residues is of general significance because it is found in the constriction zones of all known 16-stranded porins from the alpha-, beta-, and gamma-proteobacteria. J Vet Med B Infect Dis Vet Public Health, 2002 Apr, 49(3), 135 - 41 A simple random amplified polymorphic DNA genotyping method for field isolates of Dermatophilus congolensis; Larrasa J et al.; Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses . Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated . Standard DNA extraction methods are not always successful for D . congolensis due to its complex life cycle, one stage of which is encapsulated . Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D . congolensis field isolates . Our results suggest that genotypic variation between isolates correlates with host species . Several DNA extraction methods and RAPD protocols were compared . An extraction method based on incubation of the bacterium in lysozyme, sodium dodecyl sulphate (SDS) and proteinase K treatments and phenolic extraction yielded high-quality DNA, which was used to optimize RAPD-polymerase chain reaction (PCR) protocols for two random primers . An alternative rapid, non-phenolic extraction method based on proteinase K treatment and thermal shock was selected for routine RAPD typing of isolates . DNA extracted from reference strains from cattle, sheep and horse using either method gave reproducible banding patterns with different DNA batches and different thermal cyclers . The rapid DNA extraction method and RAPD-PCR were applied to 38 D . congolensis field isolates . The band patterns of the field and type isolates correlated with host species but not with geographical location. Indian J Exp Biol, 2001 Jul, 39(7), 673 - 7 Mechanism of removal of aflatoxin B1 by a resistant bacterium; Vaithiyanathan S et al.; A bacterium resistant to aflatoxin B1 isolated from the soil was shown to remove a maximum 26% of toxin at 3 microg ml(-1) . A comparison of spectrophotometric and radioisotope methods showed that a maximum of 48 hr was sufficient to remove the toxin . Radioisotope analysis showed that the radioactivity decreased in the chloroform phase while it increased in the aqueous phase during the time course of the experiment . An analysis of the supernatant of culture medium showed that the bacterium had converted aflatoxin B1 to water soluble compounds with lambda(max) of 338 and 374. New Microbiol, 2002 Apr, 25(2), 253 - 7 Isolation of Bartonella henselae from domestic cats in an Italian urban area; Cabassi CS et al.; Bartonella henselae is the causative agent of Cat Scratch Disease (CSD) in humans . Cat is considered the reservoir of the bacterium . Identification of bacteriemic cats is the basic tool in the prophylaxis of CSD . Blood samples were collected between January 1999-December 2000 from 248 domestic cats living in an urban area (Reggio Emilia) in Northern Italy and tested for Bartonella henselae bacteriemia . Cultural and PCR methods were used . PCR was used directly on cat blood as well as to identify the Bartonella strain growth in culture . 24 (9.7 %) cats were found bacteriemic, most of which aged <1 year . A higher sensitivity was demonstrated by cultural method compared with PCR. Am J Vet Res, 2002 May, 63(5), 757 - 62 Chemotaxis, phagocytosis, and oxidative metabolism in bovine macrophages exposed to a novel interdigital phlegmon (foot rot) lesion isolate, Porphyromonas levii; Walter MR et al.; OBJECTIVE: To examine the host response toward Porphyromonas levii, by evaluating chemotaxis, phagocytosis, and oxidative burst of bovine macrophages in vitro . SAMPLE POPULATION: Cultured bovine macrophages obtained from monocytes harvested from blood samples of 15 Holstein steers . Porphyromonas levii was isolated from the foot rot lesion of an acutely affected feedlot steer . PROCEDURE: Monocytes were cultured for macrophage differentiation over 7 days . Porphyromonas levii was cultured in strict anaerobic conditions for experimentation . Chemotaxis was evaluated by quantifying macrophage migration toward P . levii in Boyden chambers . Phagocytosis was assessed by quantification of macrophages engulfing P . levii following incubation with or without anti-P . levii serum or purified IgG . Oxidative burst was measured by use of the nitroblue tetrazolium reduction assay . RESULTS: Chemotaxis toward P . levii was not significantly different from control values at any of the tested bacterial concentrations . Phagocytosis of P . levii was approximately 10% at a 10:1 bacterium to macrophage ratio and did not change significantly over time . When higher proportions of P . levii were tested for phagocytosis, the 1,000:1 bacterium to macrophage ratio had a significant increase, compared with the 10:1 test group . Opsonization of P . levii with high-titeranti-P . levii serum or anti-P . levii IgG produced a significant increase in macrophage phagocytosis . Oxidative production significantly increased compared with control in the 1,000:1 test group only . CONCLUSIONS AND CLINICAL RELEVANCE: Porphyromonas levii may evade host detection by decreased chemotaxis, phagocytosis, and oxidative burst by macrophages . Acquired immunity may be beneficial for clearance of P . levii in foot rot lesions in cattle. Extremophiles, 2002 Apr, 6(2), 89 - 95 Transcriptional regulation under pressure conditions by RNA polymerase sigma54 factor with a two-component regulatory system in Shewanella violacea; Nakasone K et al.; Deep-sea bacteria have unique systems for gene and protein expression controlled by hydrostatic pressure . One of the sigma factors, sigma54, was found to play an important role in pressure-regulated transcription in a deep-sea piezophilic bacterium, Shewanella violacea . A glutamine synthetase gene (glnA) has been targeted as a model for the pressure-regulated promoter to investigate transcriptional regulation by the sigma54 factor . Recognition sites for sigma54 and sigma70 factors were observed at an upstream region of the glnA, and NtrC-binding sites were also identified at the same region . Primer extension analyses revealed that the transcription initiation sites of both promoters were determined and that transcription from the sigma54 site was regulated by elevated pressure . The sigma54 promoter is known to be activated by a two-component signal transduction system, the NtrB-NtrC phosphorylation relay . Our results suggested that this system might be regulated by deep-sea conditions and that the gene expression controlled by the sigma54 promoter was actually regulated by pressure . We propose a possible model of the molecular mechanisms for pressure-regulated transcription. Infect Immun, 2002 Jun, 70(6), 3304 - 7 Proteolysis of CD14 on human gingival fibroblasts by arginine-specific cysteine proteinases from Porphyromonas gingivalis leading to down-regulation of lipopolysaccharide-induced interleukin-8 production; Tada H et al.; Arginine-specific cysteine proteinases (gingipains-R) from periodontopathic Porphyromonas gingivalis cleaved CD14, a bacterial pattern recognition receptor, on human gingival fibroblasts (HGF) . Consequently, gingipains-R reduced lipopolysaccharide-induced interleukin-8 production by HGF, indicating that gingipains-R inhibited CD14-dependent HGF activation and are involved in immune evasion by the bacterium in periodontal tissues. Infect Immun, 2002 Jun, 70(6), 2899 - 907 LsaA, an antigen involved in cell attachment and invasion, is expressed by Lawsonia intracellularis during infection in vitro and in vivo; McCluskey J et al.; Lawsonia intracellularis has been identified recently as the etiological agent of proliferative enteropathies, which are characterized by intestinal epithelial hyperplasia and associated moderate immune responses . This disease complex has been reported in a broad range of animals, prevalently in pigs, and L . intracellularis has been linked with ulcerative colitis in humans . L . intracellularis is an obligate intracellular bacterium, and the pathogenic mechanisms used to cause disease are unknown . Using in vitro-grown organisms as a source of genomic DNA, we identified a Lawsonia gene which encodes a surface antigen, LsaA (for Lawsonia surface antigen), associated with attachment to and entry into cells . The deduced amino acid sequence of this protein showed some similarity to members of a novel protein family identified in a number of other bacterial pathogens but for which roles are not fully defined . Transcription of this gene was detected by reverse transcription-PCR in L . intracellularis grown in vitro in IEC18 cells and in bacteria present in ileal tissue from infected animals . Immunohistochemistry with specific monoclonal antibody and immunoblotting with sera from infected animals demonstrated that LsaA protein is synthesized by L . intracellularis during infection . Expression of this gene during infection in vitro and in vivo suggests that this surface antigen is involved during infection, and phenotypic analysis indicated a role during L . intracellularis attachment to and entry into intestinal epithelial cells Biochem J, 2002 Sep 1, 366(Pt 2), 573 - 83 Isoprenoid biosynthesis in higher plants and in Escherichia coli: on the branching in the methylerythritol phosphate pathway and the independent biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate; Hoeffler JF et al.; In the bacterium Escherichia coli, the mevalonic-acid (MVA)-independent 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway is characterized by two branches leading separately to isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) . The signature of this branching is the retention of deuterium in DMAPP and the deuterium loss in IPP after incorporation of 1-{4-(2)H}deoxy-d-xylulose ({4-(2)H}DX) . Feeding tobacco BY-2 cell-suspension cultures with {4-(2)H}DX resulted in deuterium retention in the isoprene units derived from DMAPP, as well as from IPP in the plastidial isoprenoids, phytoene and plastoquinone, synthesized via the MEP pathway . This labelling pattern represents direct evidence for the presence of the DMAPP branch of the MEP pathway in a higher plant, and shows that IPP can be synthesized from DMAPP in plant plastids, most probably via a plastidial IPP isomerase. Biochim Biophys Acta, 2002 May 20, 1597(1), 123 - 32 Purification and characterization of ferredoxin-NAD(P)(+) reductase from the green sulfur bacterium Chlorobium tepidum; Seo D et al.; Ferredoxin-NAD(P)(+) reductase {EC 1.18.1.3, 1.18.1.2} was isolated from the green sulfur bacterium Chlorobium tepidum and purified to homogeneity . The molecular mass of the subunit is 42 kDa, as deduced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) . The molecular mass of the native enzyme is approximately 90 kDa, estimated by gel-permeation chromatography, and is thus a homodimer . The enzyme contains one FAD per subunit and has absorption maxima at about 272, 385, and 466 nm . In the presence of ferredoxin (Fd) and reaction center (RC) complex from C . tepidum, it efficiently catalyzes photoreduction of both NADP(+) and NAD(+) . When concentrations of NADP(+) exceeded 10 microM, NADP(+) photoreduction rates decreased with increased concentration . The inhibition by high concentrations of substrate was not observed with NAD(+) . It also reduces 2,6-dichlorophenol-indophenol (DPIP) and molecular oxygen with either NADPH or NADH as efficient electron donors . It showed NADPH diaphorase activity about two times higher than NADH diaphorase activity in DPIP reduction assays at NAD(P)H concentrations less than 0.1 mM . At 0.5 mM NAD(P)H, the two activities were about the same, and at 1 mM, the former activity was slightly lower than the latter. Environ Pollut, 2002, 118(3), 427 - 33 Role of loosely bound humic substances and humin in the bioavailability of phenanthrene aged in soil; Nam K et al.; A study was conducted to determine a possible role of loosely bound humic substances (i.e., humic and fulvic acids) in bioavailability of aged phenanthrene with time . In this study, long-term residence of phenanthrene in soil is defined as aging or sequestration, and the effect was determined by the declined bioavailability to bacteria of the polycyclic aromatic hydrocarbon with increased residence time . After 1, 7, and 100 days of aging of phenanthrene in Lima loam, about 90-93% of initial phenanthrene was recovered from the humin-mineral fraction of Lima loam whereas less than 12% was found in humic and fulvic acids of the same soil . Mineralization rates of phenanthrene aged in the humin-mineral fraction significantly decreased with time by the test bacterium P5-2 . In terms of extents of mineralization, the difference with time was not appreciable, but still significant at P<0.05 . Additional decreases in the rates and extents of mineralization were observed with the whole soil (i.e . Lima loam) to which phenanthrene had been aged . Data suggest that major sequestration sites for phenanthrene may reside in the humin-mineral fraction, and probably humic and fulvic acids may act as a physico-chemical barrier to bacterial degradation so that the compound's bioavailability may be limited. Biosci Biotechnol Biochem, 2002 Mar, 66(3), 489 - 500 Cloning, sequencing, and expression of a gene encoding the monomeric isocitrate dehydrogenase of the nitrogen-fixing bacterium, Azotobacter vinelandii; Sahara T et al.; Isocitrate dehydrogenase (IDH: EC 1.1.1.42) of Azotobacter vinelandii was purified to an electrophoretically homogeneous state, and a gene (icd) encoding this enzyme was cloned and sequenced . The N-terminal amino acid sequence of the purified enzyme was consistent with that deduced from the nucleotide sequence of the icd gene . The deduced amino acid sequence of this gene showed high identity (62-66%) to those of the other bacterial monomeric IDHs . Expression of the icd gene in Escherichia coli was examined by measuring the enzyme activity and mRNA level . Primer extension analyses revealed that two species of mRNAs with different lengths of 5'-untranslated regions (TS-1 and TS-2) were present, of which the 5'-terminals (TS-1 and TS-2 sites) were cytosines located at 244 bp and 101 bp upstream of translational initiation codon, respectively . Conserved promoter elements were present at -35 and -10 regions from the TS-1 site, whereas no such a common motif was found in the upstream region of the TS-2 site . Deletion of the promoter elements upstream of the TS-1 site resulted in complete loss of IDH activity in the E . coli transformant . When the promoter elements upstream of the TS-1 site were intact, the levels of TS-1 and TS-2 were varied greatly by altering exogenous nutrients for growth . The cells grown in a nutrient-rich medium produced large amounts of TS-1 and had a low level of IDH activity . In a nutrient-poor medium, the cells contained large amounts of TS-2 and high levels of IDH activity. Science, 2002 May 10, 296(5570), 1124 - 6 Role of delayed nuclear envelope breakdown and mitosis in Wolbachia-induced cytoplasmic incompatibility; Tram U et al.; The bacterium Wolbachia manipulates reproduction in millions of insects worldwide; the most common effect is cytoplasmic incompatibility (CI) . We found that CI resulted from delayed nuclear envelope breakdown of the male pronucleus in Nasonia vitripennis . This caused asynchrony between the male and female pronuclei and, ultimately, loss of paternal chromosomes at the first mitosis . When Wolbachia were present in the egg, synchrony was restored, which explains suppression of CI in these crosses . These results suggest that Wolbachia target cell cycle regulatory proteins . A striking consequence of CI is that it alters the normal pattern of reciprocal centrosome inheritance in Nasonia. Curr Drug Metab, 2002 Apr, 3(2), 159 - 73 Tetrahydrobiopterin biosynthesis, utilization and pharmacological effects; Werner-Felmayer G et al.; Tetrahydrobiopterin (H4-biopterin) is an essential cofactor of a set of enzymes that are of central metabolic importance, i.e . the hydroxylases of the three aromatic amino acids phenylalanine, tyrosine, and tryptophan, of ether lipid oxidase, and of the three nitric oxide synthase (NOS) isoenzymes . As a consequence, H4-biopterin plays a key role in a vast number of biological processes and pathological states associated with neurotransmitter formation, vasorelaxation, and immune response . In mammals, its biosynthesis is controlled by hormones, cytokines and certain immune stimuli . This review aims to summarize recent developments concerning regulation of H4-biopterin biosynthetic and regulatory enzymes and pharmacological effects of H4-biopterin in various conditions, e.g . endothelial dysfunction or apoptosis of neuronal cells . Also, approaches towards gene therapy of diseases like the different forms of phenylketonuria or of Parkinson's disease are reviewed . Additional emphasis is given to H4-biopterin biosynthesis and function in non-mammalian species such as fruit fly, zebra fish, fungi, slime molds, the bacterium Nocardia as well as to the parasitic protozoan genus of Leishmania that is not capable of pteridine biosynthesis but has evolved a sophisticated salvage network for scavenging various pteridine compounds, notably folate and biopterin. Photochem Photobiol, 2002 Apr, 75(4), 433 - 6 Spectral heterogeneity in single light-harvesting chlorosomes from green sulfur photosynthetic bacterium chlorobium tepidum; Saga Y et al.; The fluorescence emission properties of single chlorosomes from the green sulfur photosynthetic bacterium Chlorobium (Chl.) tepidum are studied for the first time, using a total internal reflection fluorescence microscope . The fluorescence peak positions of bacteriochlorophyll (BChl)-c self-aggregates in a single chlorosome of Chl . tepidum were widely distributed in the wavelength region between 750 and 768 nm, and the standard deviation (s.d . = 4.1 nm, n = 51) was larger than that of single chlorosomes of Chloroflexus (Cfl.) (s.d . = 1.9 nm, n = 50) . The spectral heterogeneity among single chlorosomes from Chl . tepidum was in sharp contrast to those from Cfl . aurantiacus . The difference of chlorosomal spectral properties between Chl . tepidum and Cfl . aurantiacus at the single-unit level would be ascribed to the homolog composition of BChl-c--chlorosomes of Chl . tepidum have BChl substituted with various alkyl groups at both the 8- and 12-positions, whereas light-harvesting BChl-c molecules in Cfl . chlorosomes have the same substituents at the 8- (ethyl group) and 12- (methyl group) positions. J Voice, 2002 Mar, 16(1), 87 - 91 The prevalence of Helicobacter pylori infection in benign laryngeal disorders; Rubin JS et al.; Helicobacter pylori (HP) is an accepted cause of chronic active gastritis and has a major causative role in peptic ulcers . It is a gastric carcinogen . Its role in nonulcer dyspepsia (NUD) is less clear, yet 50% of patients with NUD are infected with HP, and some recent literature demonstrates long-term improvement of symptoms following eradication . HP has been investigated in several other organ systems, but has not been investigated to any major degree in laryngeal disorders, a region that could be directly exposed to the bacterium from pharyngolaryngeal reflux . This study represents one arm of a larger study designed to investigate such a relationship . Of 101 patients with nonmalignant voice disorders presenting to our voice clinics, 54.5% tested positive for the H . pylori organism . Of the controls, 47.1% tested positive . When striated into age groups of < 45 years, 46-61 years, and > 62 years, and then age-matched with the controls, the likelihood of infection with the H . pylori organism was greater in both the experimental middle group, and in the middle group when combined with the elder group, than in the matched controls, and this difference demonstrated a trend approaching statistical significance . This finding is discussed in the light of other studies on HP and on gastroesophageal reflex (GER). Proc Nutr Soc, 2002 Feb, 61(1), 137 - 43 Salivary antioxidants and periodontal disease status; Sculley DV et al.; Periodontal disease is a common chronic adult condition . The bacterium Porphyromonas gingivalis has been implicated in the aetiology of this disease, which causes destruction of the connective tissue and bone around the root area of the tooth . It has been observed that invading P . gingivalis bacteria trigger the release of cytokines such as interleukin 8 and tumour necrosis factor a, leading to elevated numbers and activity of polymorphonucleocytes (PMN) . As a result of stimulation by bacterial antigens, PMN produce the reactive oxygen species (ROS) superoxide via the respiratory burst as part of the host response to infection . Patients with periodontal disease display increased PMN number and activity . It has been suggested that this proliferation results in a high degree of ROS release, culminating in heightened oxidative damage to gingival tissue, periodontal ligament and alveolar bone . Antioxidant constituents in plasma have been well-documented, being chiefly ascorbate, albumin and urate, and these are known to display sensitivity to dietary antioxidant intakes . The concentration of antioxidants in saliva does not appear to mirror those of plasma . The extent of dietary influence upon salivary antioxidant status is unclear . Urate is the predominant salivary antioxidant, with albumin and ascorbate providing minor contributions . Previous research has found reduced salivary antioxidant activity in patients suffering from periodontal disease . An improved understanding of the role antioxidants play in periodontitis, and the influence of nutrition on antioxidant status, may lead to a possible nutritional strategy for the treatment of periodontal disease. Life Sci Space Res, 1973, 11, 247 - 59 The radiobiological effects of heavy ions on mammalian cells and bacteria; Grigoryev YG et al.; The radiobiological effects of heavy ions have been studied in experiments with mouse corneal epithelium, liver cells of rats irradiated in vivo, and the bacterium Escherichia coli B . From exposure of E . coli B to radiations with different LET, the effectiveness of the modifying influence of anoxia and some other radioprotectors has been determined. Curr Microbiol, 2002 Jun, 44(6), 406 - 10 Methanogenesis from furfural by defined mixed cultures; Boopathy R; Methanogenesis from furfural by defined mixed cultures was studied . Under sulfate-reducing conditions, a Desulfovibrio strain was used as the furfural-degrading species producing acetic acid . This sulfate-reducing bacterium (SRB) Desulfovibrio strain B is an incomplete oxidizer, unable to carry out the terminal oxidation of organic substrates, leaving acetic acid as the end product . Introduction of acetate-utilizing methanogenic archaeon Methanosarcina barkeri 227 converted acetic acid to methane . This well-defined mixed consortium used furfural as its sole source of carbon and converted it to methane and CO(2) . In the mixed culture, when a methanogen inhibitor was used in the culture medium, furfural was converted to acetic acid by the Desulfovibrio strain B, but acetic acid did not undergo further metabolism . On the other hand, when the growth of Desulfovibrio in the consortium was suppressed with a specific SRB inhibitor, namely molybdate, furfural was not degraded . Thus, the metabolic activities of both Desulfovibrio strain B and M . barkeri 227 were essential for the complete degradation of furfural. Biosci Biotechnol Biochem, 2002 Feb, 66(2), 471 - 5 Molecular cloning of the gene encoding a novel beta-N-acetylhexosaminidase from a marine bacterium, Alteromonas sp . strain O-7, and characterization of the cloned enzyme; Tsujibo H et al.; We have reported that the chitinolytic system of Alteromonas sp . strain O-7 consists of chitinases (ChiA, ChiB, and ChiC), a chitinase-like enzyme (ChiD), beta-N-acetylglucosaminidases (GlcNAcasesA, GlcNAcaseB, and GlcNAcaseC), and a novel transglycosylative enzyme (Hex99) . The gene encoding a beta-hexosaminidase with an unusual substrate specificity (hex86), located upstream of the hex99 gene, was cloned and sequenced . The gene encoded a protein of 761 amino acids with a calculated molecular mass of 86,758 Da . The deduced amino acid sequence of Hex86 showed sequence similarity with beta-hexosaminidases belonging to family 20 . The hex86 gene was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity . The enzyme rapidly cleaved p-nitrophenyl-beta-N-acetyl-D-glucosaminide and slowly cleaved p-nitrophenyl-beta-N-acetyl-D-galactosaminide . Unexpectedly, the enzyme did not hydrolyzed chitin oligosaccharides under the assay conditions for synthetic glycosides . However, after prolonged incubation with excessive quantities of the enzyme, Hex86 hydrolyzed chitin oligosaccharides . These results indicate that Hex86 is a novel enzyme that prefers p-nitrophenyl-beta-N-acetyl-D-glucosaminide to chitin oligosaccharides as a substrate. Biosci Biotechnol Biochem, 2002 Feb, 66(2), 416 - 21 Isolation and characterization of the genes encoding two metalloproteases (MprI and MprII) from a marine bacterium, Alteromonas sp . strain O-7; Miyamoto K et al.; An extracellular alkaline metalloprotease (MprI) from Alteromonas sp . strain O-7 was purified and characterized . The molecular mass of the purified enzyme was estimated to be 56 kDa by SDS-PAGE . The optimum pH and temperature were pH 10.0 and 60 degrees C, respectively . The gene (mprI) encoding MprI was cloned and its nucleotide sequence was analyzed . The deduced amino acid sequence of MprI showed significant similarity to metalloproteases classified into the thermolysin family . Furthermore, sequence analysis showed that another metalloprotease (MprII)-encoding gene was located downstream from mprI . The deduced amino acid sequence of MprII showed high similarity to metalloproteases of the aminopeptidase family . Similar repeated C-terminal extensions were found in both MprI and MprII. Wien Med Wochenschr, 2002, 152(5-6), 135 - 40 {Significance of Helicobacter pylori infection for stomach lymphoma and stomach carcinoma}; Dragosics B; The discovery of Helicobacter pylori in 1983 revolutionised pathogenetic hypotheses of almost all gastric diseases and markedly enhanced research especially in the field of malignant tumours of this organ . Based on epidemiological studies indicating an association of H . pylori infection and malignant gastric tumours the WHO classified this bacterium as "class I carcinogen" already in 1994 . Although the high prevalence of this germ worldwide is sharply contrasting the low incidence of gastric carcinomas and lymphomas its role as independent risk factor in the carcinogenesis of these tumours today is reasonably evidence-based . Thus, epidemiologists are calculating a reduction of 80% of all MALT-type lymphomas and of about 60% of gastric "non cardia" carcinomas in the scenario of an "H . pylori-free" world . However, complete remission of 80% of early lymphomas of MALT-type confined to mucosa and submucosa, only, after antibiotic eradication of the bacterium is well established in literature and follow-up data are confirming sustained response after years . The strength of impact of an H . pylori infection on gastric carcinogenesis will be figured out by prospective studies on a non infected population in the future. Carbohydr Res, 2002 Apr 30, 337(9), 869 - 72 Structure of the O-specific polysaccharide of the lipopolysaccharide of Azospirillum brasilense Sp245; Fedonenko YP et al.; An O-specific polysaccharide was isolated from the lipopolysaccharide of a plant-growth-promoting bacterium Azospirillum brasilense Sp245 and studied by sugar analyses along with one- and two-dimensional 1H and 13C NMR spectroscopy, including NOESY . The polysaccharide was found to be a new rhamnan with a pentasaccharide repeating unit having the following structure:-->2)-beta-D-Rhap-(1-->3)-alpha-D-Rhap-(1-->3)-alpha-D-Rhap-(1-->2)-alpha-D-Rhap-(1-->2)-alpha-D-Rhap-(1--> Nat Rev Mol Cell Biol, 2002 Mar, 3(3), 167 - 76 Dynamic localization of proteins and DNA during a bacterial cell cycle; Jensen RB et al.; A cellular differentiation programme that culminates in an asymmetric cell division is an integral part of the cell cycle in the bacterium Caulobacter crescentus . Recent work has uncovered mechanisms that ensure the execution of many events at different times during the cell cycle and at specific places in the cell . Surprisingly, in this one-micron bacterial cell, the dynamic spatial disposition of regulatory proteins, structural proteins and specific regions of the chromosome are important components of both cell-cycle progression and the generation of daughter cells with different cell fates. Mol Microbiol, 2002 May, 44(3), 819 - 28 Pyruvate kinase from Chlamydia trachomatis is activated by fructose-2,6-bisphosphate; Iliffe-Lee ER et al.; Pyruvate kinase is the final regulatory point in the catabolic Embden-Meyerhoff-Parnas pathway, which controls the carbon flux of glycolytic intermediates and regulates the level of ATP in the cell . In a previous study, we identified, cloned and sequenced pyruvate kinase from the obligate intracellular bacterium Chlamydia trachomatis and demonstrated that the enzyme was active in crude extract . Here, we report the kinetic properties of highly purified C . trachomatis pyruvate kinase . The results indicate that C . trachomatis pyruvate kinase is 53.5 kDa with a pH optima of 7.3 . Kinetic studies show that C . trachomatis pyruvate kinase requires both K+ and Mg2+ ions for activity, exhibits sigmoidal kinetics with respect to phosphoenolpyruvate and Michaelis-Menten kinetics with respect to ADP . In addition, C . trachomatis pyruvate kinase is able to use alternative nucleoside diphosphates as phosphate acceptors, although it shows the greatest activity with ADP . In contrast to other bacterial pyruvate kinases that are activated by AMP, our data show that AMP, in addition to ATP and GTP, inhibits C . trachomatis pyruvate kinase . Surprisingly, unlike any other known bacterial pyruvate kinase, C . trachomatis pyruvate kinase was allosterically activated by fructose-2,6-bisphosphate, an important regulatory metabolite that has only been reported in eukaryotes. Bioorg Med Chem Lett, 2002 May 20, 12(10), 1339 - 42 A novel type of nonsteroidal estrone sulfatase inhibitors; Jutten P et al.; Madurahydroxylactone (MHL) is a secondary metabolite produced by the soil bacterium Nonomuria rubra and belongs to the family of benzo{a}naphthacenequinones . We report the initial results and structure-activity relationships of our study into a series of thiosemicarbazone derivatives of madurahydroxylactone as potential nonsteroidal inhibitors of the enzyme estrone sulfatase . The most active compound, the cyclohexylthiosemicarbazone, was shown to be a non-competitive inhibitor with a K(i) of 0.35microM . This compound is devoid of estrogenic properties and showed low acute toxicity in the hen's fertile egg screening test. Dig Dis Sci, 2002 Apr, 47(4), 823 - 30 Cellular immune responses in Helicobacter heilmannii infection: evaluation of the role of the host and the bacterium; Cinque SM et al.; We evaluated some aspects of the immune response to Helicobacter heilmannii in two mouse strains . Gastritis that was more severe in infected C57BL/6 mice . A proliferative response to H . pylori antigens was observed in splenocytes from H . heilmannii-positive and -negative mice, similar in the positive- and negative-BALB/c mice, but lower in the positive- than in the negative-C57BL/6 animals . A decrease in B cells and an increase in CD4+ cells after stimulation with type I H . pylori antigen and an increase in CD8+ cells after stimulation with type I and II antigens was observed in infected C57BL/6 mice . Conversely, the percentage of CD4+, CD8+, and B cells was similar in positive- and negative-BALB/c mice . These results demonstrated that the immune response is similar in H . heilmannii and H . pylori infection and strengthened the importance of host and bacterial virulence markers in the immune response to gastric Helicobacter infections. Scand J Gastroenterol, 2002 Apr, 37(4), 409 - 13 Role of Helicobacter pylori CagA+ infection in determining oxidative DNA damage in gastric mucosa; Papa A et al.; BACKGROUND: Although Helicobacter pylori is a risk factor for gastric cancer, the role of the bacterium in the development of this malignancy is not defined precisely . Reactive oxygen species (ROS) could play an important role in carcinogenesis by inducing DNA damage . The aims of the present study were: 1) to assess the production of ROS and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a sensitive marker of oxidative DNA injury, in gastric mucosa, according to H . pylori status and cytotoxic associated gene product A (CagA); 2) to determine the relationship between ROS generation and amount of 8-OHdG . METHODS: Gastric biopsy specimens were obtained from 60 consecutive patients . ROS generation was measured by luminol enhanced chemiluminescence . 8-OHdG detection was performed by an immunoperoxidase method, using a specific anti 8-OHdG monoclonal antibody . RESULTS: 40/60 patients (67%) were H . pylori-positive . ROS generation was significantly higher in patients positive for H . pylori infection as compared to negative . 8-OHdG detection was performed in 30 patients in which CagA presence was also investigated . High expression of 8-OHdG was detected in 14/20 (70%) H . pylori-positive patients (13 CagA+ and 1 CagA-) and in 2/10 (20%) H . pylori-negative patients . A significant correlation was found between ROS production and 8-OHdG content . CONCLUSION: H . pylori infection by a CagA+ strain is associated with the highest production of ROS to which a severe oxidative DNA damage corresponds . This sequence of events could support the hypothesis that the oxygen-free radicals-mediated damage due to H . pylori cytotoxic strains could be a driving force that leads from chronic gastritis to gastric carcinoma. Microbiology, 2002 May, 148(Pt 5), 1439 - 46 An essential virulence protein of Brucella abortus, VirB4, requires an intact nucleoside-triphosphate-binding domain; Watarai M et al.; Brucella abortus is a facultative intracellular bacterium capable of surviving inside macrophages . The VirB complex, which is highly similar to conjugative DNA transfer apparatuses, is required for intracellular replication . A conserved NTP-binding domain in VirB4 suggests that one or both proteins couple energy by NTP hydrolysis to transport of putative effector molecule(s) . Here it is shown that a mutant strain of B . abortus that contains an in-frame deletion in virB4 is unable to replicate in macrophages and survives in mice . Intracellular replication and virulence in mice are fully restored by expressing virB4 in trans, indicating that VirB4 is essential for intracellular replication and virulence in mice . An alteration within the NTP-binding region of VirB4 by site-directed mutagenesis abolished complementation of a virB4 mutant, demonstrating that an intact NTP-binding domain is critical for VirB4 function . Intracellular replication was inhibited in wild-type B . abortus after introducing a plasmid expressing a mutant VirB4 altered in the NTP-binding region . The dominant negative phenotype suggests that VirB4 either functions as a multimer or interacts with some other component(s) necessary for intracellular replication . Wild-type B . abortus-containing phagosomes lack the glycoprotein LAMP-1, which is an indicator of the normal endocytic pathway . Mutant strains were found in phagosomes that co-localized with LAMP-1, indicating that VirB4 containing the intact NTP-binding region is essential for evasion of fusion with lysosomes. J Gastroenterol Hepatol, 2002 Jan, 17(1), 27 - 31 Reinfection rate following effective therapy against Helicobacter pylori infection in Japan; Adachi M et al.; BACKGROUND AND AIM: In developed countries, reinfection of Helicobacter pylori (H . pylori) after eradication of the bacterium is unusual, while the reinfection rate in developing countries is variable . In this study, we determined the reinfection rate after successful H . pylori eradication in Japan, a country with a high prevalence of H . pylori infection . METHODS: After successful eradication, 377 patients were followed up by endoscopy and urea breath test annually . In reinfected patients, H . pylori strains isolated initially and after reinfection were compared by using random amplification of polymorphic DNA fingerprinting . RESULTS: H . pylori became positive in four of 337 patients (1.2) 1 year after eradication and in two of 133 patients (1.5) 2 years after eradication . One patient experienced an ulcer relapse 2 years after eradication therapy . Random amplification of polymorphic DNA fingerprinting of the isolated strains from four of the six patients showed two had identical strains (at 1 year) while the other two had different strains (one at 1 year and one at 2 years) . When infection in the two patients reinfected with identical strains is considered a recrudescence, the true reinfection rate is < 0.8 per patient year . CONCLUSIONS: The reinfection rate after eradication of H . pylori is low in Japan despite the country's high prevalence of H . pylori infection. Proc Natl Acad Sci U S A, 2002 May 14, 99(10), 7078 - 83 Epub 2002 Apr 30. Repression of photosynthesis gene expression by formation of a disulfide bond in CrtJ; Masuda S et al.; Many species of purple photosynthetic bacteria repress synthesis of their photosystem in the presence of molecular oxygen . The bacterium Rhodobacter capsulatus mediates this process by repressing expression of bacteriochlorophyll, carotenoid, and light-harvesting genes via the aerobic repressor, CrtJ . In this study, we demonstrate that CrtJ forms an intramolecular disulfide bond in vitro and in vivo when exposed to oxygen . Mutational and sulfhydryl-specific chemical modification studies indicate that formation of a disulfide bond is critical for CrtJ binding to its target promoters . Analysis of the redox states of aerobically and anaerobically grown cells indicates that they have similar redox states of approximately -200 mV, thereby demonstrating that a change in midpoint potential is not responsible for disulfide bond formation . In vivo and in vitro analyses indicate that disulfide bond formation in CrtJ is insensitive to the addition of hydrogen peroxide but is sensitive to molecular oxygen . These results suggest that disulfide bond formation in CrtJ may differ from the mechanism of disulfide bond formation used by OxyR. J Gastroenterol Hepatol, 2002 Apr, 17(4), 495 - 502 Gastric cancer: laboratory bench to clinic; Houghton J et al.; Gastric cancer is the second most common cause of cancer-related mortality worldwide and the 14th overall cause of death . Detection of disease usually occurs at an advanced stage and overall survival rates for gastric cancer are poor . Our current model for gastric cancer progression clearly maintains Helicobacter infection as the primary inducer of gastric metaplastic and neoplastic disease . Helicobacter pylori is a ubiquitous organism, infecting more than half the world's population . It has been suggested that this infection directly contributes to the formation of gastric cancer in up to 80% of cases; however, gastric malignancy develops in only a subset (< 1%) of infected patients . Therefore, predisposition to Helicobacter-associated gastric cancer is most likely multifactorial, including the interaction of bacterial, host and environmental components . Our understanding of how the organism interacts with the gastric mucosa and synergizes with dietary and other environmental factors to induce malignant mucosal changes is evolving . Indeed, H . pylori has direct effects on the gastric mucosa, but the major factor in disease progression appears to be a robust host Th1 immune response in the setting of a permissive environment . In combination, these factors predispose to the formation of atrophy, metaplasia and gastric cancer . Understanding the interaction of the bacterium with the host and the environment can potentially identify patients most at risk . Identifying potentially removable factors (in addition to H . pylori infection) in the acquisition and progression of neoplastic disease may provide targets for early intervention and prevention strategies . J Basic Microbiol, 2002, 42(2), 127 - 31 Characterization of JP-7 jet fuel degradation by the bacterium Nocardioides luteus strain BAFB; Jung CM et al.; In the fall of 1996, numerous bacteria capable of degrading JP-7 jet fuel were isolated from soil collected at Beale Air Force Base in northern California . The most prevalent organism, identified as Nocardioides luteus by16s rRNA sequencing (MIDI Labs, Inc.), was selected for further analysis . Analysis of JP-7 following inoculation with N . luteus demonstrated degradation of the C(11) alkane component of the fuel . Growth rates of N . luteus were determined with alkanes of various lengths as the sole carbon and energy source . The organism grew best on shorter length alkanes (C(8) and C(10)) . Growth was measurably slower on C(11), and minimal on C(12), C(13), and C(14). Graefes Arch Clin Exp Ophthalmol, 2002 Apr, 240(4), 291 - 5 Epub 2002 Mar 12. Outbreak of Empedobacter brevis endophthalmitis after cataract extraction; Janknecht P et al.; BACKGROUND: We present a series of patients who were operated upon on the same day by the same surgeon . All of those patients developed postoperative endophthalmitis due to Empedobacter brevis - a bacterium hitherto unknown in ophthalmologic literature . METHODS: Twelve patients were referred because of endophthalmitis after cataract extraction . The patients' files were studied and the intraoperative and postoperative outcome was analysed . RESULTS: Twelve patients (five male, seven female, mean age 75 years) presented 1-6 days after uncomplicated cataract extraction . Although some suffered from medical or ophthalmological diseases there was no association with the severity of the endophthalmitis . Eleven patients required vitrectomy, seven as primary procedure, one primary with extraction of the lens and three secondary after anterior chamber lavage and intravitreal antibiotics . In three cases vitrectomy had to be repeated together with extraction of the intraocular lens . There were two postoperative retinal detachments that required silicon oil and in one case an encircling band . Mean visual acuity rose from 0.02 to 0.47 by 9 months after operation . Empedobacter brevis was found in the anterior chamber and in the vitreous in all except one patient . CONCLUSION: In high-volume cataract surgery endemic endophthalmitis is always possible . Sources of infection may be anything from the lens to the sterilisation process, the latter being the primary suspect in our series . Prompt, adequate and (if necessary) aggressive treatment by vitreous surgery may lead to favourable results. J Bacteriol, 2002 May, 184(10), 2748 - 54 Biological properties and cell tropism of Chp2, a bacteriophage of the obligate intracellular bacterium Chlamydophila abortus; Everson JS et al.; A number of bacteriophages belonging to the Microviridae have been described infecting chlamydiae . Phylogenetic studies divide the Chlamydiaceae into two distinct genera, Chlamydia and Chlamydophila, containing three and six different species, respectively . In this work we investigated the biological properties and host range of the recently described bacteriophage Chp2 that was originally discovered in Chlamydophila abortus . The obligate intracellular development cycle of chlamydiae has precluded the development of quantitative approach