Zentralbl Bakteriol, 1998 Jul, 288(1), 121 - 9 The complement-killing of Borrelia burgdorferi . Target antigens and sensitizing antibodies; Cacciapuoti B et al.; It had been previously shown by the Microbial Adherence Immobilization Assay (MAIA) that Borrelia burgdorferi sensu stricto, type strain B31 was clumped, immobilized and killed in vitro by sensitizing antibodies that activated the classical complement pathway and the complement-killing of live borrelia . In the present study, the target antigens and sensitizing antibodies responsible for the complement-killing of borrelia were investigated, using MAIA as a selective identification tool . It was found that the fractions containing the 31 and 34 kDa outer surface proteins from strain B31 were the unique antigens producing sensitizing antibodies in rabbits that activated the complement-killing of B31 . An anti-OspB, but not an anti-OspA, monoclonal antibody did activate the B31 complement-killing in MAIA . From these results, constraints on the effectiveness of OspB and OspA as immunogens for the prevention and control of Lyme borreliosis in humans are discussed. Int J Food Microbiol, 1998 Jul 21, 42(3), 159 - 66 Degradation of pectic compounds during pasteurised vegetable juice spoilage by Chryseomonas luteola: a predictive microbiology approach; Membre JM et al.; Predictive modelling consists in describing effects of environmental factors on microbial growth parameters . With food spoilage bacteria, this approach must be extended to both growth and food damage characterisation . In order to study the incidence of storage temperature on vegetable damage, using predictive microbiology tools, kinetics of pectic compound degradation were studied . Chryseomonas luteola has been chosen because of its ability to grow on post-harvested vegetables . Experiments were performed at refrigerated temperatures (0-10 degrees C) with low initial bacterial charges (10(1)-10(3.5) cfu/ml) . Microbial specific growth rate (mu), stability phase before pectic degradation (Sp) and alteration percentage (Ap) were chosen as reference parameters . Then, sub-optimal temperature effects on these three parameters were estimated using modified Ratkowsky model . Results obtained in synthetic medium were compared with data observed in endive juice to appreciate the alteration of vegetable during post-harvest storage. J Infect Dis, 1998 Sep, 178(3), 783 - 91 An outbreak of bloodstream infections arising from hemodialysis equipment; Arnow PM et al.; An outbreak of 29 cases of bloodstream infection by 16 pathogens occurred during 8 months at two chronic hemodialysis centers . Consequences included 21 hospital admissions and removal of 23 dialysis catheters . An epidemiologic investigation comparing case-patients with uninfected controls showed that risk was significantly (P < .05) associated with having a catheter for vascular access; receiving treatment on a Monday, Wednesday, Friday schedule; and receiving treatment on one heavily contaminated dialysis machine . Culture studies and mock trials showed that bloodstream pathogens were present in a recently installed, commercially marketed attachment for disposal of spent priming saline and could enter blood line tubing directly or indirectly during dialyzer priming and tubing assembly . The outbreak was halted by measures directed at the attachment . Investigation of this problem demonstrated that microbial overgrowth in the attachment caused bloodstream infections and underscores the importance of microbiologic considerations in the design and use of hemodialysis equipment. Antibiot Khimioter, 1998, 43(7), 7 - 11 {Gradient extraction of ammonium specific ionophore antibiotics from mycelium}; Sverdlova AN et al.; Streptomyces brunneofungs 118 and S.griseolus 224 were isolated from natural objects and shown to synthesize ammonium specific products belonging to macrotetrolide compounds . Gradient extraction was applied to the mycelium and it was demonstrated that the compounds were rather labile both in the native cells and on synthetic carriers and could be hydrolyzed by aqueous solutions of acetone and ethanol to various linear oligomers of narctinic acids . Acetone mainly stabilized the monomer and dimer fragments whereas in the ethanol extracts a complete set of the oligomers (from the monomer to the tetramer) was detectable . Graident extract of suspension of the microbial intact cells is useful in the study of some properties and the primary identification of biologically active hydrophobic products even at the early stages of their isolation. Appl Environ Microbiol, 1998 Sep, 64(9), 3238 - 45 Nucleic acid (DNA, RNA) quantification and RNA/DNA ratio determination in marine sediments: comparison of spectrophotometric, fluorometric, and HighPerformance liquid chromatography methods and estimation of detrital DNA Dell'Anno A, Fabiano M, Duineveld GCA, Kok A, Danovaro R. In this study, we compared three methods for extraction and quantification of RNA and DNA from marine sediments: (i) a spectrophotometric method using the diphenylamine assay; (ii) a fluorometric method utilizing selective fluorochromes (thiazole orange for total nucleic acids and Hoechst 33258 for DNA); and (iii) a high-pressure liquid chromatography (HPLC) method which uses a specific column to separate RNA and DNA and UV absorption of the nucleic acids for quantification . Sediment samples were collected in the oligotrophic Cretan Sea (eastern Mediterranean, from 40 to 1,540 m in depth) and compared to the distribution and composition of the benthic microbial assemblages (i.e., bacteria and microprotozoa) . DNA concentrations measured spectrophotometrically and by HPLC were not significantly different, while fluorometric yields were significantly lower . Such differences appear mainly due to fact that the stain-DNA complex is strongly dependent on the DNA composition and structure . RNA concentrations determined by the three methods displayed some differences; fluorometric and spectrophotometric methods obtain RNA concentration by difference and therefore may be biased by DNA estimates . By contrast, the HPLC method provides independent assessments of RNA and DNA concentrations . We tentatively estimated the contribution of the detrital DNA to the total DNA pools in two ways . The two calculations provided quite similar results indicating that the majority of the DNA pool in the deep-sea sediments was detrital . Microbial RNA generally accounted for almost the entire sedimentary RNA pools below 100-m depth . RNA concentrations were found to decrease along the Cretan shelf and slope . The RNA/DNA ratio calculated by using fluorometric DNA concentrations was significantly correlated with values of sediment community oxygen consumption only below 100-m depth (dominated by the microbial biomass) . These data suggest that the RNA/DNA ratio, based on fluorometric estimates of DNA, can be used as an indicator of benthic metabolic activity, but only when metazoan contribution to the microbial DNA is negligible. Appl Environ Microbiol, 1998 Sep, 64(9), 3422 - 8 Genotypic and phenotypic responses of a riverine microbial community to polycyclic aromatic hydrocarbon contamination; Langworthy DE et al.; The phenotypic and genotypic adaptation of a freshwater sedimentary microbial community to elevated (22 to 217 microgram {dry weight} of sediment-1) levels of polycyclic aromatic hydrocarbons (PAHs) was determined by using an integrated biomolecular approach . Central to the approach was the use of phospholipid fatty acid (PLFA) profiles to characterize the microbial community structure and nucleic acid analysis to quantify the frequency of degradative genes . The study site was the Little Scioto River, a highly impacted, channelized riverine system located in central Ohio . This study site is a unique lotic system, with all sampling stations having similar flow and sediment characteristics both upstream and downstream from the source of contamination . These characteristics allowed for the specific analysis of PAH impact on the microbial community . PAH concentrations in impacted sediments ranged from 22 to 217 microgram (dry weight) of sediment-1, while PAH concentrations in ambient sediments ranged from below detection levels to 1.5 microgram (dry weight) of sediment-1 . Total microbial biomass measured by phospholipid phosphate (PLP) analysis ranged from 95 to 345 nmol of PLP g (dry weight) of sediment-1 . Nucleic acid analysis showed the presence of PAH-degradative genes at all sites, although observed frequencies were typically higher at contaminated sites . Principal component analysis of PLFA profiles indicated that moderate to high PAH concentrations altered microbial community structure and that seasonal changes were comparable in magnitude to the effects of PAH pollution . These data indicate that this community responded to PAH contamination at both the phenotypic and the genotypic level. Appl Environ Microbiol, 1998 Sep, 64(9), 3300 - 4 Aerobic growth on nitroglycerin as the sole carbon, nitrogen, and energy source by a mixed bacterial culture; Accashian JV et al.; Nitroglycerin (glycerol trinitrate {GTN}), an explosive and vasodilatory compound, was metabolized by mixed microbial cultures from aeration tank sludge previously exposed to GTN . Aerobic enrichment cultures removed GTN rapidly in the absence of a supplemental carbon source . Complete denitration of GTN, provided as the sole C and N source, was observed in aerobic batch cultures and proceeded stepwise via the dinitrate and mononitrate isomers, with successive steps occurring at lower rates . The denitration of all glycerol nitrate esters was found to be concomitant, and 1, 2-glycerol dinitrate (1,2-GDN) and 2-glycerol mononitrate (2-GMN) were the primary GDN and GMN isomers observed . Denitration of GTN resulted in release of primarily nitrite-N, indicating a reductive denitration mechanism . Biomass growth at the expense of GTN was verified by optical density and plate count measurements . The kinetics of GTN biotransformation were 10-fold faster than reported for complete GTN denitration under anaerobic conditions . A maximum specific growth rate of 0.048 +/- 0.005 h-1 (mean +/- standard deviation) was estimated for the mixed culture at 25 degreesC . Evidence of GTN toxicity was observed at GTN concentrations above 0 . 3 mM . To our knowledge, this is the first report of complete denitration of GTN used as a primary growth substrate by a bacterial culture under aerobic conditions. Chest, 1998 Aug, 114(2), 577 - 86 Effects of repetitive use and cleaning techniques of disposable jet nebulizers on aerosol generation; Standaert TA et al.; STUDY OBJECTIVE: Patients with cystic fibrosis use disposable jet nebulizers for the self-administration of antibiotics, DNase, and bronchodilators several times per day . Most patients elect to reuse their disposable nebulizers . The purpose of this study was to determine if significant changes in particle size distribution or output (mL/min) occurred with reuse . DESIGN: In vitro studies were performed using four disposable models and one durable jet nebulizer for up to 100 runs; measurements of particle size and output were obtained at 10 run intervals, using saline solution alone, tobramycin, gentamicin, or a mixture of albuterol and cromolyn . Particle size determinations were made with a laser diffraction analyzer . RESULTS: There was no significant difference between the baseline performance of the four disposable models and the durable Pari LC, when measuring particle size distribution of the aerosol; the Pari LC had an output rate two to three times higher than the four disposable models . For each of the four solutes tested, there was no clinically significant change in performance for up to 100 cycles, when the nebulizers were properly cleaned between uses . Unwashed units containing tobramycin started to fail by 40 runs . CONCLUSIONS: When properly maintained, there was no trend of deterioration of performance with repeated use of disposable nebulizers . Microbial contamination was not addressed in this study and must be considered prior to recommendations for the reuse of disposable nebulizers. J Ren Nutr, 1998 Jan, 8(1), 40 - 2 Medicinal herb use and the renal patient; Foote J et al.; Medicinal herb use, although a popular branch of alternative medicine, may be inappropriate for the renal patient . The pharmacological activity, chemical components, and microbial content of herbs, as well as their ability to interfere with prescription medications, make medicinal herbs potentially dangerous for the renal patient . The purpose of this report is to inform the medical professional of the implications of renal patients using medicinal herbs. Ann Periodontol, 1998 Jul, 3(1), 142 - 50 Periodontal diseases' contributions to cardiovascular disease: an overview of potential mechanisms; Kinane DF; Periodontitis and atherosclerosis have complex etiologies, genetic and gender predispositions, and potentially share many risk factors-the most significant of which may be smoking status . These diseases also have many pathogenic mechanisms in common . It is becoming increasingly clear that infections and chronic inflammatory conditions such as periodontitis may influence the atherosclerotic process . The severity and chronicity of periodontal disease provides a rich source of subgingival microbial and host response products and effects over a long time period . The objective of this review is to consider the mechanisms whereby diseases such as periodontitis, which is chronic and Inflammatory In nature and initiated by microbial plaque, can predispose to atherosclerosis . In common with periodontal disease . the pathogenesis of atherosclerosis is not completely understood and both diseases are currently under Intensive investigation . Two main processes in particular are worthy of consideration and may provide the link between these 2 diseases, namely the lipopolysaccharide-related responses and the hyperresponsive monocyte phenomenon . Insufficient experimental evidence exists, however, to further support these hypotheses at present and clearly more research is needed on both of these processes and the interrelationships between both diseases. Ann Periodontol, 1998 Jul, 3(1), 127 - 41 Periodontitis: a risk factor for coronary heart disease? Beck JD, Offenbacher S, Williams R, Gibbs P, Garcia R. This paper evaluates the current information on the relationship between oral disease (specifically periodontitis) and atherosclerosis/coronary heart disease (CHD) to determine whether the information is sufficient to conclude that periodontitis is a risk factor for atherosclerosis/CHD . As background for this evaluation, the term "risk factor" is defined, and the 3 criteria used to establish exposures as risk factors are reviewed . In addition, epidemiologic criteria for defining an exposure as causal are presented . The available evidence then is evaluated according to the criteria for causality, which are extensions of the criteria for establishing a risk factor . This review is done in the context of the relationship between atherosclerosis/CHD and inflammation . A number of findings are briefly reviewed that link inflammation and atherosclerosis/CHD, such as: 1) prior flu-like symptoms were more common in cases of myocardial infarction than in concurrently sampled controls; 2) high levels of cytomegalovirus antibody titers were associated with elevated carotid intimal-medial wall thickness 18 years later; 3) prior infection with cytomegalovirus was a strong independent risk factor for restenosis after coronary atherectomy; 4) dental infections were more common in cases of cerebral infarction compared to community controls matched on age and sex; and 5) the gingival index was significantly correlated with fibrinogen and white cell counts in periodontal patients and controls, adjusted for age, smoking, and socioeconomic status . Three case-control studies and 5 longitudinal studies investigating the relationship between dental conditions and atherosclerosis/CHD are reviewed in terms of strength of associations, consistency of associations, specificity . of associations, time sequence between exposure and outcome, and degree of exposure and outcome . Related to the last criterion, new findings are presented which indicate that the extent of the periodontal infection, a measure reflecting microbial burden, also is related to onset of new CHD events . Our previously published model describing the potential biological mechanisms underlying the associations found is reviewed . This model places the associations into a context of an intrinsic or acquired hyperinflammatory monocyte trait that results in a more intense inflammatory response to lipopolysaccharide (LPS) challenges, such as periodontal infections . This hyperinflammatory response may promote atheroma formation and thromboembolic events . finally, new findings from ongoing animal studies are presented, indicating that high fat diets in atherosclerotic-susceptible mice induce greater inflammatory responses to Porphyromonas gingivalis challenges . We conclude that the available evidence does allow an interpretation of periodontitis being a risk factor for atherosclerosis/CHD . This conclusion, however . is made with some qualifications . While the associations found across a wide variety of subjects are remarkably consistent, for the most part they are represented by incidence odds ratios around 2.0 . While this level of association would result in oral conditions contributing to a large number of CHD cases, it is possible that associations of this magnitude are due to bias in the study designs . In addition, some studies report that periodontitis is associated with all-cause mortality and low birth weight infants . These multiple associations detract from the credibility of periodontitis as a risk factor, as specificity of association is more often related to causality . However, all-cause mortality may largely be driven by mortality from cardiovascular events: and some exposures, such as smoking . are indeed risk factors for multiple conditions . On the other hand, current findings regarding the associations between oral conditions and atherosclerosis/CHD imply that the criteria for causality may be met in the not-too-distant future. J Clin Periodontol, 1998 Aug, 25(8), 624 - 9 Subgingival microbial profile of Papillon-Lefèvre patients assessed by DNA-probes; Lundgren T et al.; The prevalence of 18 selected bacterial species was assessed by means of "checkerboard" DNA-DNA hybridisation in a group of 12 Saudi-Arabian adolescents with Papillon-Lefevre syndrome . A total of 36 tooth sites were investigated . The patients exhibited severe periodontal disease with deep pockets . All 12 patients harboured the putative bacterial pathogens P . intermedia, F . nucleatum, P . micros and S . intermedius while T . denticola, B . forsythus, P . nigrescens, E . corrodens, S . noxia and C . rectus were recovered from 11 patients . P . gingivalis was recovered from 9 patients and 18 sites while corresponding figures for A . actinomycetemcomitans were 8 and 19, respectively . A number of the investigated species (B . forsythus, T . denticola, P . intermedia, C rectus) reached high levels (> or =10(6) cells) in more than 1/2 of the patients . On the other hand, bacteria such as A . actinomycetemcomitans and P . gingivalis were infrequently encountered at high levels in these subgingival samples . In conclusion, the analysis failed to demonstrate a PLS-specific profile of the subgingival infection, since the bacterial composition of the sampled sites closely resembled that characterising deep pockets in adult periodontitis patients. J Appl Microbiol, 1998 Mar, 84(3), 377 - 82 Variation in proteinase activities in the rumen; Falconer ML et al.; Rumen fluid was taken from fistulated sheep and a cow receiving various diets based on grass hay or grass cubes with and without cereal-based concentrates . Proteinases in the extracellular fluid, and extracted from particulate material by Triton X-100, were visualized using SDS-PAGE in which gelatin was co-polymerized with the gels . Each animal sampled had a different pattern of proteinase activity . No single proteinase band predominated, although a few appeared in several samples, indicating that some microbial species were commonly involved in proteolysis but none was dominant . The banding patterns in samples taken from the same animals two weeks apart were fairly similar, indicating some stability within animals . Patterns obtained with extracellular fluid and Triton X100 extracts of small and large particulate material from the same sample were similar for the most part, although the relative intensity of the bands differed . The serine protease inhibitor, phenyl methyl sulphonyl fluoride, had little influence on the banding pattern . Concentrate in the diet appeared to increase inter-animal variation, and sheep in adjacent pens and consuming the same grass hay:concentrate diet had different banding patterns . Thus, no microbial proteolytic enzyme was predominant in protein digestion in the rumen. Am J Infect Control, 1998 Aug, 26(4), 437 - 41 Comparison of the microbial barrier properties of a needleless and a conventional needle-based intravenous access system; Luebke MA et al.; BACKGROUND: Sporadic reports of increased infection rates involving concerning access systems, especially in home-care setting, have raised questions concerning the safety of all needleless systems . Addressing this concern, Baxter Healthcare Corporation and the Centers for Disease Control an d Prevention performed parallel laboratory studies comparing the microbial barrier properties of the Interlink (trademark of Baxter Healthcare Corporation, Deerfield, Ill) needleless system with a conventional intravenous access system . METHODS: Studies of needleless and conventional systems evaluated fluid path contamination introduced through injection site septa, which were intentionally inoculated with high levels of bacteria and subsequently punctured with a without alcohol swabbing disinfection before access . RESULTS: With disinfection, the combined effects of the disinfection technique and the barrier properties of the septa prevented the transfer of organisms into the fluid path in 94% to 96% of needleless test articles and 96% to 100% of conventional test articles . Without disinfection, the barrier properties of the septa alone prevented the transfer of organisms into the fluid path in 20% to 69% of needleless test article and 10% to 28% of conventional test articles . CONCLUSIONS: The data demonstrate the needless system performs as well as the conventional intravenous access system with respect to the risk of microbial contamination and reinforce the need for appropriate septum disinfection before accessing either system. Chem Phys Lipids, 1998 Jun, 93(1-2), 57 - 66 Insights into the molecular basis for fatty acyl specificities of lipases from Geotrichum candidum and Candida rugosa; Holmquist M; Despite immense progress in our comprehension of lipase structure and function during the past decade, the basis for lipase acyl specificities has remained poorly understood . This review summarizes some recent advances in the understanding at the molecular-level of substrate acyl recognition by two members in a group of large (Mw approximately 60 kDa) microbial lipases . Two aspects of acyl specificity will be focused upon . (i) The unique preference of a fungal Geotrichum candidum lipase for long-chain cis (delta-9) unsaturated fatty acid moieties in the substrate . Mutational analysis of this lipase identified residues essential for its anomalous acyl preference . This information highlighted for the first time parts in the lipase molecule involved in substrate acyl differentiation . These results are discussed in the context of the 3D-structure of a G . candidum lipase isoenzyme and structures of the related Candida rugosa lipase in complex with inhibitors . (ii) The mechanism by which the yeast C . rugosa lipase discriminates between enantiomers of a substrate with a chiral acyl moiety . Molecular modeling in combination with substrate engineering and kinetic analyses, identified two alternative substrate binding models . This allowed for the proposal of a molecular mechanism explaining how long-chain alcohols can act as enantioselective inhibitors of this enzyme . A picture is thus beginning to emerge of the interplay between lipase structure and fatty acyl specificity. Proc Natl Acad Sci U S A, 1998 Aug 18, 95(17), 10328 - 33 Defense gene induction in tobacco by nitric oxide, cyclic GMP, and cyclic ADP-ribose Durner J, Wendehenne D, Klessig DF. Reactive oxygen species are believed to perform multiple roles during plant defense responses to microbial attack, acting in the initial defense and possibly as cellular signaling molecules . In animals, nitric oxide (NO) is an important redox-active signaling molecule . Here we show that infection of resistant, but not susceptible, tobacco with tobacco mosaic virus resulted in enhanced NO synthase (NOS) activity . Furthermore, administration of NO donors or recombinant mammalian NOS to tobacco plants or tobacco suspension cells triggered expression of the defense-related genes encoding pathogenesis-related 1 protein and phenylalanine ammonia lyase (PAL) . These genes were also induced by cyclic GMP (cGMP) and cyclic ADP-ribose, two molecules that can serve as second messengers for NO signaling in mammals . Consistent with cGMP acting as a second messenger in tobacco, NO treatment induced dramatic and transient increases in endogenous cGMP levels . Furthermore, NO-induced activation of PAL was blocked by 6-anilino-5,8-quinolinedione and 1H-(1,2,4)-oxadiazole{4,3-a}quinoxalin-1-one, two inhibitors of guanylate cyclase . Although 6-anilino-5,8-quinolinedione fully blocked PAL activation, inhibition by 1H-(1,2,4)-oxadiazole{4, 3-a}quinoxalin-1-one was not entirely complete, suggesting the existence of cGMP-independent, as well as cGMP-dependent, NO signaling . We conclude that several critical players of animal NO signaling are also operative in plants. Mycoses, 1998, 41 Suppl 1, 51 - 5 {Airborne molds and their metabolites at workplaces in composting plants}; Fischer G et al.; Airborne fungal contaminants in composting facilities gain more and more importance in regard to health hazards for workers and an emission of spores and microbial metabolites in the environment . Possible health impacts of bioaerosols are widely discussed from both an allergological and a toxicological point of view . The present study investigates in detail the exposure to airborne fungal spores at working places in compost plants . These fungal spores are compared to the spectrum of microbial volatile metabolites with regard to the physiological properties of each fungal species . The results indicate, that the spectrum of microbial volatile organic compounds (MVOC) as well as the production of mycotoxins can be specific for certain species . In addition to the pathogenic and allergological relevance, the fungi may have different toxicological health impacts . However, an evaluation of health effects caused by the great variety of volatile organic compounds remains difficult, since information on their toxicological impact is lacking. Br J Ophthalmol, 1998 May, 82(5), 473 - 5 Evaluation of an extended period of use for preserved eye drops in hospital practice; Livingstone DJ et al.; AIM: To evaluate and compare the microbial contamination arising from 1 and 2 weeks' use of eye drops by hospital inpatients and hence determine the validity of apportioning a 2 week in use expiry date for these preparations . METHODS: Eye drop residues were collected from inpatients of Worthing, Southlands, and Brighton General hospitals after 7 days' use (341 samples) and also after 14 days' use (295 samples) . The contents of the containers were examined for the presence of contaminating bacteria and fungi . RESULTS: The incidence of microbial contamination was shown to be not significantly different (p > 0.1 chi 2 test) between the 7 and 14 day samples . In addition, the contaminating micro-organisms were of a broadly similar pattern between the two sample groups and were mostly those normally associated with the skin . Less frequent contaminants were organisms of environmental origin . None of the micro-organisms isolated were considered to be of clinical significance and the mean number of cells found per sample was very low . CONCLUSIONS: The evidence therefore suggests that increasing the period of use for eye drops in hospitals from 7 to 14 days would not present a clinically significant threat to patients' health and yet may lead to annual savings to the NHS of Pounds 0.5 million. J Dairy Sci, 1998 Jul, 81(7), 1985 - 90 In situ assessment of degradability of organic matter in the rumen of the dairy cow; Arieli A et al.; This study analyzed the relationships among the effective degradabilities of organic matter (OM) in feedstuffs, which were assessed separately by an in situ method and a direct in vivo measurement of the rumen degradation of OM in the diets of Holstein dairy cows . For this comparison, 80 individual data points were used from studies of dairy cows that were in midlactation and that had been cannulated in the rumen and abomasum . In vivo evaluation of the true degradability of OM in the rumen was based on rare earth digesta markers . Purine N served as a microbial marker . Feed samples were incubated in the rumens of dairy cows for 3, 6, 9, 12, 24, 48, and 72 h, and effective rumen degradation was calculated from the percentage of residual OM for rumen outflow rates of 4, 6, and 8%/h . Evaluations of rumen degradability of OM by the in situ method were correlated with actual in vivo measurements of rumen degradability of OM (r2 = 0.31, 0.34, and 0.37; SE of the estimate = 4.1, 4.0, and 3.9%, respectively) . We concluded that the in situ method is a useful tool for providing reliable estimates of rumen degradability of OM in dairy cows. Clin Infect Dis, 1998 Aug, 27 Suppl 1, S5 - 11 Antibiotic-selective environments; Baquero F et al.; The evolution and spread of antibiotic resistance depends on the antibiotic pressure exerted in the microbial environment . Selective effects occur in selective compartments, where particular antibiotic concentrations result in a differential growth rate of resistant bacterial variants . This may happen even at very low antibiotic concentrations able to select low-level-resistant bacteria . When more than one antibiotic is present in the environment, the multiple and fluctuating pressure produces the selection of bacterial variants that use multiple or multipurpose mechanisms or optimize a single mechanism of resistance to survive under the variable environmental conditions . Host factors such as immunity contribute to the selective process . Antibiotics themselves may promote bacterial diversity, either mediated by the random drift effect or triggering the increase of mutational events under bacterial stress . Analysis of selective environment-related antibiotic-host-bacteria interactions is essential to understanding the biology of antibiotic resistance. J Food Prot, 1998 May, 61(5), 640 - 8 The application of quantitative risk assessment to microbial food safety; Vose DJ; Quantitative risk assessment (QRA) is rapidly accumulating recognition as the most practical method for assessing the risks associated with microbial contamination of foodstuffs . These risk analyses are most commonly developed in commercial computer spreadsheet applications, combined with Monte Carlo simulation add-ins that enable probability distributions to be inserted into a spreadsheet . If a suitable model structure can be defined and all of the variables within that model reasonably quantified, a QRA will demonstrate the sensitivity of the severity of the risk to each stage in the risk-assessment model . It can therefore provide guidance for the selection of appropriate risk-reduction measures and a quantitative assessment of the benefits and costs of these proposed measures . However, very few reports explaining QRA models have been submitted for publication in this area . There is, therefore, little guidance available to those who intend to embark on a full microbial QRA . This paper looks at a number of modeling techniques that can help produce more realistic and accurate Monte Carlo simulation models . The use and limitations of several distributions important to microbial risk assessment are explained . Some simple techniques specific to Monte Carlo simulation modelling of microbial risks using spreadsheets are also offered which will help the analyst more realistically reflect the uncertain nature of the scenarios being modeled . simulation, food safety. J Food Prot, 1998 Mar, 61(3), 357 - 9 A survey of the microbial population and ethanol content of bagged salad; Hagenmaier RD et al.; Five nationally and regionally distributed brands of ready-to-eat salads in sealed bags were sampled from major supermarket chains . At time of purchase, product temperature was 4 to 7 degrees C; the mean mesophilic microbial population was 1.0 x 10(7) CFU/g; the yeast population was 210 CFU/g; the mean headspace O2 and CO2 concentrations were 1.2 and 12%, respectively; and the ethanol content was 700 ppm . For samples analyzed on the expiration date (14 to 16 days after packaging) the mean mesophilic microbial population was 6 x 10(7) CFU/g; ethanol content was 1,500 ppm; and the headspace gas had not markedly changed from time of purchase. J Food Prot, 1998 Feb, 61(2), 162 - 5 A representative microbial sampling method for large commercial containers of raw beef based on purge; Dorsa WJ et al.; The purge from beef combos ( a boxed collection of beef trimmings) was tested as a means of representatively sampling the microbial content of this raw product . In the first experiment, purge was sampled from model beef combos that had been inoculated with bovine feces. . Data from this experiment indicated a strong correlation (r = 0.94) between the total aerobic bacteria counts derived from the purge samples of a model beef combo and the total aerobic bacteria present in a rinse sample of the entire model beef combo . In a second experiment, two 500-g meat pieces were inoculated with an antibiotic-resistant Escherichia coli O157:H7 and place at various levels within a 75-cm meat column . The marked bacteria were retrievable from the purge of the meat column after 24 h, showing that bacteria are carried downward into the purge . During the third part of the study, 90 beef combos (approximately 900 kg beef/combo) were randomly selected at the receiving dock of a commercial grinding facility and sampled using both purge and concurrently used 11-g core samples . Purge samples from these combos recovered significantly greater numbers of mesophilic and psychrotrophic aerobic bacteria, coliforms, and E . coli than core samples from the same combos . Additionally, coliforms and E . coli were recoverable from 100% and 80%, respectively, of the purge samples taken, whereas core samples were only able to recover 60% and 40%, respectively, from the same combos . These findings indicate that a purge sample from a beef combo is a more efficacious sampling method for determining the general bacterial profile and identifying the presence of coliforms and E . coli than randomly taken core samples. J Food Prot, 1998 Jan, 61(1), 73 - 7 Rheological properties and lipid oxidation of rice decontaminated with low-energy electrons; Hayashi T et al.; Microbial load and quality of rice grains which were exposed to electrons at different acceleration voltages of 170 to 200 kV were examined to evaluate the efficacy of decontaminating rice with low-energy electrons . Electrons at any acceleration voltage between 170 and 200 kV reduced microbial loads of brown rice grains to levels lower than 10 colony-forming units (CFU)/g . Higher acceleration voltages resulted in a lower viscosity and a higher thiobarbituric acid value (TBA) . Milling at a yield of 90 or 88% after electron treatment made the viscosity and TBA of rice treated with electrons at 170 kV almost the same as untreated rice . Low and high compression analyses of rice grains which were exposed to electrons at 170 to 180 kV and milled at a yield of 90% followed by cooking showed almost the same hardness and stickiness as untreated grains which were milled at 90% . The results indicate that milling at a yield of 90% or lower removes the portion of rice exposed to electrons at 170 kV and that treatment of brown rice with low-energy electrons enables the preparation of milled rice with extremely low levels of microbial load and little quality deterioration. J Food Prot, 1998 Jan, 61(1), 57 - 65 Variations over time of microbial load and physicochemical properties of floor materials after cleaning in food industry premises; Mettler E et al.; Changes over time of microbial load, surface free energy, and roughness of a variety of floor materials were investigated after hygiene operations in meat, pastry, and milk processing environments . Measurements were made in the laboratory on test plates which had been inserted in floors of food premises and subjected to the habitual fouling-cleaning cycles for up to 16 weeks . Microbial contamination of floor materials, assessed after sonication, appeared to be controlled in the milk site, which was generally dry . In both pastry and meat sites a specific microbial population developed and could stabilize to levels up to 10(4) and 10(6) CFU cm(-2), respectively . In the meat site bacterial contamination could be as high as 10(7) CFU cm(-2) on one rough floor material . After introduction in the premises, all flooring materials tended to have similar surface free energy values that could be simulated in the laboratory either perfectly by conditioning the surface with the treated food (in the case of the milk premises) or approximately by conditioning the surface with the hygiene agents used (in the case of the meat and pastry premises). Curr Biol, 1998 Jul 30-Aug 13, 8(16), 943 - 6 Parallel evolution of CCR5-null phenotypes in humans and in a natural host of simian immunodeficiency virus; Palacios E et al.; The C-C chemokine receptor CCR5 in humans and rhesus macaques (Macaca mulatta) serves as the primary coreceptor for cellular entry by macrophagetropic strains of human immunodeficiency virus type 1 (HIV-1) and all reported strains of simian immunodeficiency virus (SIV) {1-6} . Humans homozygous for a 32 bp deletion allele of CCR5, resulting in a null phenotype, are highly resistant to infection by HIV-1 {7-9}, prompting development of therapies and vaccines targeting CCR5 . We now report a novel deletion allele of CCR5, with an allele frequency of 0.04, in sooty mangabey monkeys (Cercocebus torquatus atys), a natural host of SIV (SIVsmm) {10} . The mutant protein was not expressed at the cell surface and accordingly did not function as a viral coreceptor . Primary activated lymphocytes from mangabeys heterozygous for the deletion allele expressed significantly less CCR5 on the cell surface . Moreover, SIV seroprevalence and viremia were comparable among CCR5 heterozygotes and wild-type animals . Parallel evolution of CCR5-null alleles in humans and sooty mangabeys suggests that similar negative selection pressures have acted against CCR5, as would occur during epidemics of infectious agents that require CCR5 for pathogenesis . Sooty mangabeys bred to homozygosity for the deletion allele will be useful for experimental studies on the context-dependent role of CCR5 in host defense and microbial pathogenesis. J Clin Microbiol, 1998 Sep, 36(9), 2477 - 80 Improved identification of mycobacteria by using the microbial identification system in combination with additional trimethylsulfonium hydroxide pyrolysis; Muller K et al.; The MIDI automated Microbial Identification System (MIS) uses gas chromatography (GC) analysis of whole-cell fatty acid methyl esters (FAMEs) between 9 and 20 carbons in length to characterize a wide range of bacterial genera and species, including mycobacteria . Mycolic acid cleavage products (MACPs) with chain lengths of C22 to C26 are not released by MIDI sample preparation of mycobacteria . Therefore, the MIS library search report often matches several mycobacterial species without any significant difference in the similarity indices . The problem is solved by adding trimethylsulfonium hydroxide (TMSH) instead of sodium sulfate in the last step of sample preparation, thus allowing the identification of MACPs in addition to FAMEs . Only one GC run parameter has to be changed: the temperature program must be extended from 260 to 310 degrees C . The MIS library search report for the identification of bacteria is not disturbed by TMSH . The combination of conventional library search report with the information of typical MACP patterns yields significantly better discrimination of mycobacterial species than the MIDI method allows. Int J Food Microbiol, 1998 May 26, 41(2), 85 - 101 Overview of gut flora and probiotics; Holzapfel WH et al.; Scientific developments in recent years have opened new frontiers and enable a better understanding of the gastrointestinal tract (GIT) as a complex and delicately balanced ecosystem . This paper focuses on more recent information related to the microbial population of the GIT and its functional role in human physiology and health . Special attention is also given to modern approaches for improving or stabilising the intestinal system and its functioning by the deliberate application of viable microbial cultures, so-called 'probiotics', selected for special functional properties. Vox Sang, 1998, 74 Suppl 2, 135 - 41 Post-transfusion hepatitis: current risks and causes; Holland PV; Viral hepatitis which follows transfusions (post-transfusion hepatitis) may be due to those transfusions, i.e., transfusion-transmitted hepatitis (TTH), or may be incident to the reason for the transfusion and, thus, may be transfusion-associated, but not transfusion-transmitted . The current risks of TTH, today, are extremely small, but are still due, primarily, to the hepatitis B virus (HBV) and the hepatitis C virus (HCV), the latter, formerly being known as "non-A, non-B hepatitis." The residual, now, of TTH which is non-A, non-B, and non-C is extremely small and may be due to a variety of agents . Using volunteer (unpaid), repeat, blood donors, who are carefully screened for hepatitis risk factors and then tested for evidence of HBV infection, the risk of HBV being transmitted by a transfusion today is in the order of 1 per 63,000 units of blood . For transfusion-transmitted HCV, with the same repeat, volunteer (unpaid) donors, careful screening and a sensitive assay for anti-HCV, the risk is in the order of 1 in 125,000 units . These risks of HBV and HCV due to transfusions are so small that other means of acquiring these viruses should be sought when patients develop hepatitis following blood transfusions . However, efforts to further reduce the current risks of HBV and HCV transmission by transfusions should continue; these include restricting transfusions to those which are necessary or appropriate, utilizing alternatives to transfusion, employing novel assays to detect viral nucleic acids, and, finally, implementing various microbial inactivation techniques on blood, blood components and plasma derivatives. Crit Rev Food Sci Nutr, 1998 Jul, 38(5), 353 - 80 Reinterpretation of microbial survival curves; Peleg M et al.; The heat inactivation of microbial spores and the mortality of vegetative cells exposed to heat or a hostile environment have been traditionally assumed to be governed by first-order reaction kinetics . The concept of thermal death time and the standard methods of calculating the safety of commercial heat preservation processes are also based on this assumption . On closer scrutiny, however, at least some of the semilogarithmic survival curves, which have been considered linear are in fact slightly curved . This curvature can have a significant effect on the thermal death time, which is determined by extrapolation . The latter can be considerably smaller or larger depending on whether the semilogarithmic survival curve has downward or an upward concavity and how the experimenter chooses to calculate decimal reduction time . There are also numerous reports of organisms whose semilogarithmic survival curves are clearly and characteristically nonlinear, and it is unlikely that these observations are all due to a mixed population or experimental artifacts, as the traditional explanation implies . An alternative explanation is that the survival curve is the cumulative form of a temporal distribution of lethal events . According to this concept each individual organism, or spore, dies, or is inactivated, at a specific time . Because there is a spectrum of heat resistance in the population--some organism or spores are destroyed sooner, or later, than others--the shape of the survival curve is determined by its distributions properties . Thus, semilogarithmic survival curves whether linear or with an upward or a downward concavity are only reflections of heat resistance distributions having a different, mode variance, and skewness, and not of mortality kinetics of different orders . The concept is demonstrated with published data on the lethal effect of heat on pathogens and spores alone and in combination with other factors such as pH or high pressure . Their different survival patterns are all described in terms of different Weibull distribution of resistances as a first approximation, although alternative distribution functions can also be used . Changes in growing or environmental condition shift the resistances distribution's mode and can also affect its spread and skewness . The presented concept does not take into account the specific mechanisms that are the cause of mortality or inactivation--it only describes their manifestation in a given microbial population . However, it is consistent with the notion that the actual destruction of a critical system or target is a probabilistic process that is due, at least in part, to the natural variability that exists in microbial populations. Science, 1998 Aug 14, 281(5379), 978 - 80 Alteration of oceanic volcanic glass: textural evidence of microbial activity Fisk MR, Giovannoni SJ, Thorseth IH. The subsurface biosphere may constitute as much as 50 percent of Earth's biomass . Direct and indirect evidence suggests that an extensive biosphere exists in the rocks below the sea floor . This survey of basalts of the Atlantic, Pacific, and Indian Oceans supports the hypothesis that bacteria have colonized much of the upper oceanic crust, which has a volume estimated at 10(18) cubic meters . Although this is the largest habitat on Earth, its low abundance of bacteria constitutes much less than 1 percent of Earth's biomass. Gynecol Obstet Invest, 1998 Aug, 46(2), 91 - 5 Interleukin-6 concentrations in cervical secretions in the prediction of intrauterine infection in preterm premature rupture of the membranes; Rizzo G et al.; The objective of this study was to determine the value of interleukin-6 (IL-6) in cervical secretion to diagnose microbial invasion of the amniotic cavity in patients with premature rupture of the membranes . Cervical secretions were sampled immediately before amniocentesis in 124 patients with singleton pregnancies and preterm premature rupture of the membranes . Gestational age ranged between 24 and 32 weeks . Amniotic fluid was cultured and IL-6 measured in amniotic fluid and cervical secretions . A total of 33.8% (21/124) of the amniotic fluid cultures had positive results . In cervical secretions the median concentration of IL-6 was 672 pg/ml (range 5-1,250) in the presence of intra-amniotic infection in contrast to 95.5 pg/ml (range 12-640) in women with negative amniotic fluid culture (p </=0.001) . There were no differences between IL-6 concentrations in the cervical secretions of patients with or without obvious leakage of amniotic fluid . A significant relationship was found between IL-6 levels in amniotic fluid and in cervical secretions (rho = 0.74, p </=0.001) . An IL-6 level in cervical secretions >200 pg/ml had a sensitivity of 78.5%, a specificity of 73.1% and a relative risk of 4.6 for intra-amniotic infection . Receiver-operator characteristics curve analysis showed that IL-6 assay in cervical secretions is comparable to IL-6 assay in amniotic fluid in predicting intra-amniotic infection (p = 0.468) . In conclusion, intra-amniotic infection is associated with increased levels of IL-6 and concentrations in cervical secretions are related to amniotic levels . The measurement of IL-6 in cervical secretions may help to noninvasively identify intra-amniotic infection among pregnancies with preterm premature rupture of membranes. Environ Health Perspect, 1998 Aug, 106 Suppl 4, 1033 - 9 Interactions between metals and microbial communities in New Bedford Harbor, Massachusetts; Ford T et al.; The fate of toxic metals in marine sediments depends on a combination of the physical, chemical, and biologic conditions encountered in any given environment . These conditions may vary dramatically, both spatially and temporally, in response to factors ranging from seasonal changes and storm events to human activities such as dredging or remediation efforts . This paper describes a program designed to evaluate the interrelationships between the microbial community and pollutants in the New Bedford Harbor, Massachusetts, area, a U.S . Environmental Protection Agency designated Superfund site . Research has focused on establishing distributional relationships between contaminant metals, fluxes of metals between sediments and the overlying water, changes in microbial diversity in response to metals, and potential use of the microbial community as a biomarker of contaminant availability . This research has shown that a significant flux of metals to the water column is mediated by benthic biologic activity, and that microbial communities may be a responsive marker of contaminant stress . A combination of biogeochemical studies and the use of molecular tools can be used to improve our understanding of the fate and effect of heavy metals released to aquatic systems. Rom J Virol, 1993 Jan-Jun, 44(1-2), 61 - 7 {Features of the patho-morphology of arteriopathies associated with viral and infra-microbial infections}; Petica M et al.; Presence of Mycoplasma Chlamydia, Rickettsia burnetii, influenza type B, herpes and adenoviruses was detected by immunofluorescence in artery fragments collected from patients with arteriopathy . Pathohistological examination of the samples revealed inflammatory--lympho-histiocytic infiltration--and mostly dystrophic alterations . Arteriopathies were localised mostly at the pelvic limb level, especially on femoral artery . Their incidence was statistically significant. Biotechnol Prog, 1998 Jul, 14(4), 657 - 60 Comments on the mechanism of microbial cell disruption in high-pressure and high-speed devices Shirgaonkar IZ, Lothe RR, Pandit AB. The dominant mechanism for microbial cell disruption in a high-pressure homogenizer and a high-speed homogenizer used in this study has been identified . It was found that the cavity collapse and the pressure pulse resulting from such a collapse have a significant influence on the rates of cell disruption . The similarities among the operating conditions for the decomposition of the aqueous KI solution to liberate iodine, the reaction occurring only under cavitating conditions, and that required for the substantial disruption of microbial cells have been pointed out . The liberation of iodine by the aqueous KI decomposition is treated as evidence of cavitation, and hence microbial cell disruption occurring at an identical discharge pressure confirms the mechanism of cell disruption as cavitation, in the high-pressure homogenizer valve . In the case of the high-speed homogenizer, shear and cavitation both play a significant role in cell disruption. Fertil Steril, 1998 Aug, 70(2), 315 - 9 Value of detecting leukocytospermia in the diagnosis of genital tract infection in subfertile men; Trum JW et al.; OBJECTIVES: To evaluate whether detection of leukocytospermia in a routine semen analysis is of diagnostic value in selecting men with an "actual" microbial infection and to assess the association between leukocytospermia and a history of bacterial and viral infections . DESIGN: Prospective clinical study . SETTING: Infertility clinic at the Center for Reproductive Medicine, Academic Medical Center, Amsterdam, the Netherlands . PATIENT(S): One hundred eighty-four men among subfertile couples attending our infertility clinic . INTERVENTION(S): The number of leukocytes was assessed in three semen samples . Serologic tests were performed, as was transurethral culture after digital prostatic massage . MAIN OUTCOME MEASURE(S): Diagnosis of actual bacterial and viral infections in relation to seminal leukocyte concentrations . The association of a history of sexually transmitted diseases with seminal leukocyte concentration . RESULT(S): An actual bacterial infection was present in 39% of men, and 11% of men had an actual viral infection . The area under the receiver operating curve, which was used to determine whether detection of leukocytospermia was of diagnostic value in identifying men with actual bacterial or viral infections, was 0.55 and 0.56 for bacterial and viral infection, respectively . A past infection with N . gonorrhoeae was associated with the presence of leukocytospermia . A past viral infection was not associated with leukocytospermia . CONCLUSION(S): Detection of leukocytospermia appears to be of no diagnostic value for selection of men with actual microbial infections, but leukocytospermia is associated with a history of gonorrhea. J Vet Dent, 1994 Aug, 11(2), 75 - 9 Assessment methods and clinical outcomes: chemical and microbial composition, formation, and maturation dynamics of pellicle, plaque, and calculus; Hefferren JJ et al.; Understanding the functional dynamics of the oral cavity helps researchers design methods to predict clinical outcomes . Most information about the oral cavities of companion animals must be drawn from animal studies designed to understand human oral disease and from human studies . Based upon functional criteria for any animal or experimental research study, supragingival plaque and calculus can be assessed within four to six weeks . Although longer studies may be more appealing, such study designs may compromise the oral soft tissue health of the animals and are complicated by oral cavity dynamics . Thus, they are less sensitive and predictive of longer term clinical outcomes . Additional research is necessary to relate tooth surface accumulation phenomena with oral soft tissue health. Eur J Biochem, 1998 Jul 1, 255(1), 133 - 8 Identification and proteolytic processing of procardosin A; Ramalho-Santos M et al.; Plant aspartic proteinases contain a plant-specific insert (PSI) of about 100 amino acids of unknown function with no similarity with the other aspartic proteinases but with significant similarity with saposins, animal sphingolipid activator proteins . PSI has remained elusive at the protein level, suggesting that it may be removed during processing . To understand the molecular relevance of PSI, the proteolytic processing of cardosin A, the major aspartic proteinase from the flowers of cardoon (Cynara cardunculus L.) was studied . Procardosin A, a 64-kDa cardosin A precursor containing PSI and the prosegment was identified by immunoblotting using monospecific antibodies against PSI and the prosegment . Procardosin A undergoes proteolytic processing as the flower matures . PSI was found to be removed before the prosegment, indicating that during processing the enzyme acquires a structure typical of mammalian or microbial aspartic proteinase proforms . In vitro studies showed that processing of PSI occurs at pH 3.0 and is inhibited by pepstatin A and at pH 7.0 . Sequence analysis allowed the identification of the cleavage sites, revealing that PSI is removed entirely, probably by an aspartic proteinase . Cleavage of the PSI scissile bonds requires, however, a conformation specific to the precursor since isolated cardosins and pistil extracts were unable to hydrolyse synthetic peptides corresponding to the cleavage sites . In view of these results, a model for the proteolytic processing of cardosin A is proposed and the molecular and physiological relevance of PSI in plant aspartic proteinase is discussed. Epidemiol Infect, 1998 Jun, 120(3), 251 - 6 Nosocomial outbreak of colonization and infection with Stenotrophomonas maltophilia in preterm infants associated with contaminated tap water; Verweij PE et al.; Between March and May 1996 Stenotrophomonas maltophilia was cultured from endotracheal aspirate samples from five preterm infants in a neonatal intensive care unit (NICU) . Four infants were superficially colonized, but a fifth died due to S . maltophilia septicaemia . S . maltophilia was cultured from tap water from three outlets in the NICU including one with a previously unnoticed defective sink drain . Water from these outlets was used to wash the preterm infants . Environmental and clinical S . maltophilia isolates yielded identical banding patterns on random arbitrary polymorphic DNA (RAPD) PCR analysis . The outbreak was controlled by reinforcement of hand disinfection, limitation of the use of tap water for hand washing and by using sterile water to wash the preterm infants . We conclude that tap water should not be used for washing preterm infants in the NICU, unless steps are taken to prevent microbial growth in the outlets. PDA J Pharm Sci Technol, 1998 May-Jun, 52(3), 100 - 9 Microbial limits reviewed: the basis for unique Australian regulatory requirements for microbial quality of non-sterile pharmaceuticals; Tang S; The need to retain Australian regulatory requirements for non-sterile pharmaceutical products has been questioned following publication of guideline limits in the 1996 Addendum to the British Pharmacopoeia (BP) . The Therapeutic Goods Administration (TGA) contends that, in some respects, the BP limits, formulated by the European Pharmacopoeial Commission, do not provide for adequate patient safety . The case for retention of TGA guidelines is based on laboratory investigation into the microbial quality of product groups on the Australian market, and an assessment of the risk to patients of microbial contamination in pharmaceutical products which are not manufactured as sterile. Nature, 1998 Jul 23, 394(6691), 392 - 5 Developmental selection of var gene expression in Plasmodium falciparum; Chen Q et al.; The protozoan Plasmodium falciparum causes lethal malaria . Adhesion of erythrocytes infected with P . falciparum to vascular endothelium and to uninfected red blood cells (rosetting) may be involved in the pathogenesis of severe malaria . The binding is mediated by the antigenically variant erythrocyte-membrane-protein-1 (PfEMP-1), which is encoded by members of the P . falciparum var gene family . The control of expression and switching of var genes seems to lack resemblance to mechanisms operating in variant gene families of other microbial pathogens . Here we show that multiple, distinct var gene transcripts (about 24 or more) can be detected by reverse transcription and polymerase chain reaction in bulk cultures of the rosetting parasite FCR3S1.2, despite the adhesive homogeneity of the cultures . We also detected several var transcripts in single erythrocytes infected with a ring-stage parasite of FCR3S1.2, and found that different var genes are transcribed simultaneously from several chromosomes in the same cell . In contrast, we detected only one var transcript, FCR3S1.2 var-1, which encodes the rosetting PfEMP-1 protein, in individual rosette-adhesive trophozoite-infected cells, and we found only one PfEMP-1 type at the erythrocyte surface by labelling with 125iodine and immunoprecipitation . We conclude that a single P . falciparum parasite simultaneously transcribes multiple var genes but, through a developmentally regulated process, selects only one PfEMP-1 to reach the surface of the host cell. Curr Opin Biotechnol, 1998 Jun, 9(3), 263 - 9 Molecular genetics of biosurfactant production Sullivan ER. Biosurfactants are surface-active microbial products that have numerous industrial applications . The molecular genetics of two structurally diverse biosurfactants, a glycolipid and a lipopeptide, were the first to be characterized . Recent advances include the identification of the structural genes for a second lipopeptide, and the isolation of a gene responsible for enhanced emulsification activity of a high molecular weight biopolymer . New insight has also developed in the regulatory mechanisms of the originally described biosurfactants, both of which are controlled by quorum sensing, a mechanism bacteria use to monitor cell density. J Anim Sci, 1998 Jul, 76(7), 1945 - 54 Monensin effects on digestion of corn or barley high-concentrate diets; Surber LM et al.; We conducted two experiments to determine the effects of monensin addition on digestion of high-concentrate diets based on corn or barley and to identify any interactions between grain source and monensin addition . A replicated in vitro experiment with a 2 x 4 factorial arrangement was used to evaluate monensin addition (0 or 72 mg/kg in vitro substrate) and grain source (corn, Gunhilde barley {GUN}, Harrington barley {HAR}, or Medallion barley {MED}) . Triplicate tubes for each treatment were incubated for 0, 3, 6, 9, 12, 18, 24, and 30 h . Rate and extent of IVDMD were determined . Four ruminally and abomasally cannulated steers were used in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to test the effects of monensin addition (0 vs 270 mg x steer(-1) x d(-1)) and grain source (70% corn vs 80% Medallion barley) . Diets were balanced to be isocaloric and isonitrogenous . An interaction (P < .10) was found between monensin addition and grain source for IVDMD during 3 through 9 h of incubation . Monensin increased the IVDMD of GUN and MED, but it decreased the IVDMD of HAR . Corn IVDMD was not affected by monensin addition . Steers fed Medallion barley had greater (P < .05) microbial protein synthesis, rate of in situ DM and starch disappearance, ruminal and postruminal digestion of starch, ruminal total VFA concentrations, and total tract digestion of DM, OM, and starch compared with steers fed corn . Monensin addition decreased (P < .10) ruminal digestion of feed N and ruminal proportions of acetate and butyrate and increased (P < .001) the ruminal proportion of propionate . No monensin x grain source interactions were observed for the variables measured in vivo. J Anim Sci, 1998 Jul, 76(7), 1753 - 9 Influence of dietary magnesium level on growth-performance and metabolic responses of Holstein steers to laidlomycin propionate; Ramirez JE et al.; We used 216 Holstein steers (151 kg) in a 262-d trial to evaluate the influence of dietary magnesium level (.19, .25, and .32%) and laidlomycin propionate (LP; 0 vs 11 ppm, air-dry basis) on growth performance and NE value of the diet . During the initial 112 d of the trial, LP increased (P < .01) ADG (6.3%) and feed efficiency (4.2%) . From d 112 until slaughter, LP increased (P < .05) ADG (9.7%) and feed efficiency (4.5%) . Across the 262-d feeding period, LP supplementation enhanced (P < .01) ADG (8.9%) and feed efficiency (6.3%) . There was an interaction (P < .05) between dietary Mg and LP on NE value of the diet . The enhancement in NE value of the diets owing to LP with .19, .25, and .32% dietary Mg were .5, 3.0, and 5.9%, respectively . Six Holstein steers (302 kg) were used in a 6 x 6 Latin square experiment to evaluate treatment effects on characteristics of ruminal and total tract digestion . There were no treatment interactions (P > .10) on site and extent of digestion of OM, starch, and N . Supplemental Mg increased (quadratic effect, P < .10) ruminal OM digestion . Neither LP nor dietary Mg level affected (P > .10) ruminal digestion of starch and feed N . Supplemental LP decreased (15%, P < .05) ruminal microbial efficiency . Total tract digestion of OM and N increased (linear effect, P < .01) with increasing dietary Mg level . There were interactions between LP and dietary Mg level on ruminal soluble-Mg concentration (linear effect, P < .01) and Mg absorption (quadratic effect, P < .05) . Apparent total tract Mg digestion increased owing to LP (P < .01) and dietary Mg level (linear effect, P < .01) . There were no treatment effects (P > .10) on ruminal pH . Dietary Mg level did not influence (P > .10) ruminal VFA concentrations or molar proportions . Supplemental LP increased (14%; P < .10) total ruminal VFA concentration but did not affect (P > .10) VFA molar proportions . We conclude that LP will increase daily weight gain and feed efficiency of calf-fed Holstein steers and that this response may be enhanced by increasing dietary Mg level. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1998 Jul, 86(1), 65 - 8 Evaluation of the levels of oral Candida in patients with Sjögren's syndrome; Abraham CM et al.; OBJECTIVE: The purpose of this study was to investigate the levels of oral Candida in patients with Sjogren's syndrome METHODS: The Candida count and salivary flow rate of patients with Sjogren's syndrome were compared with those of healthy control subjects . Candida cultures were obtained from oral rinses . The numbers of colony-forming units were determined through use of the Spiral System . RESULTS: The mean Candida count of patients with Sjogren's syndrome was 1672 +/- 1455 colony-forming units per mL; the count of healthy control subjects was 0.00 colony-forming units per mL . The mean salivary flow rate of patients with Sjogren's syndrome was significantly lower than that of healthy control subjects (0.16 +/- 0.13 mL/min/gland vs 0.55 +/- 0.24 mL/min/gland, respectively; p = 0.0001) . However, Spearman rank correlation analyses did not reveal a significant correlation between salivary flow rate and Candida count (in colony-forming units per mL) among patients with Sjogren's syndrome . CONCLUSIONS: Alteration in the oral microbial flora in patients with Sjogren's syndrome may be enhanced by the reduction in salivary output. Microb Comp Genomics, 1997, 2(2), 123 - 39 GRS: a graphic tool for genome retrieval and segment analysis; Sicheritz-Ponten T et al.; GRS is a graphic tool for retrieval and visualization of genome segments from partially or completely sequenced genomes . To facilitate visual identification of conserved genomic motifs, genes are color-coded according to their presumed functional roles . Aligned genes can be rapidly screened for potential homology by automatic retrieval and alignment of the corresponding protein sequences . Furthermore, the map location of any genome segment can be visually compared to the position of the same segment in other genomes or to the position of other segments within the same genome . The gene string analysis option of GRS allows the identification of genes that are identically arranged in any pairwise set of genomes . Finally, the program allows the user to create new gene table format files to enable comparisons of gene order structures in recently determined sequence data to the patterns of genes in already existing microbial and organellar databases . With the help of GRS, the genomic contexts of genes for which no identifiable homologues exist can be analyzed to provide an additional source of information for sequence annotations . We illustrate the use of GRS by analyzing the structure and distribution of phylogenetically conserved motifs in closely as well as more distantly related microbial genomes. Curr Microbiol, 1998 Sep, 37(3), 151 - 5 Oxygenic photosynthesis and respiratory activity in microbial mats of the ebro delta, spain, by oxygen exchange method Urmeneta J, Alcoba, Razquin E, Tarroja E, Navarrete A, Guerrero R. Photosynthetic and respiratory activities at low light intensities (300 &mgr;E m-2 s-1) in the microbial mats of the Ebro Delta were measured by the oxygen exchange method in the laboratory . The response to H2S concentration, a significant factor in the dynamics of that ecosystem, was assessed . Total photosynthesis reached 23 . 78-28.17 &mgr;g O2 cm-2 h-1 . Photosynthetic activity was not significantly different at the two temperatures tested . Respiratory activity reached a consumption of 6.95-8.56 &mgr;g O2 cm-2 h-1 at 25 degreesC and 11.42-11.70 &mgr;g O2 cm-2 h-1 at 35 degreesC . The Q10 value for respiration was 1.37-1.64 . Oxygen production in Microcoleus chthonoplastes, the most abundant cyanobacterium in those microbial mats, was highly resistant to sulfide inhibition . Concentrations less than 0.02 mM sulfide did not affect the rate of photosynthesis . Concentrations up to 0.1 mM sulfide caused different degrees of partially reversible inhibition, with a maximum of 67% at 0.78 mM sulfide . Primary production (g C assimilated/m2/year) in those microbial mats was also assessed and compared with data from other ecosystems. Appl Environ Microbiol, 1998 Aug, 64(8), 3102 - 5 Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene; Bradley PM et al.; Anaerobic oxidation of {1,2-14C}vinyl chloride and {1, 2-14C}dichloroethene to 14CO2 under humic acid-reducing conditions was demonstrated . The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought. Appl Environ Microbiol, 1998 Aug, 64(8), 3066 - 9 Minimally invasive detection of Piscirickettsia salmonis in cultivated salmonids via the PCR; Marshall S et al.; The attributes of the PCR allowed implementation of an assay for specific detection of Piscirickettsia salmonis from a few microliters of fish serum . This opens the way to less invasive modes of sampling for this microbial pathogen in salmonids. Appl Environ Microbiol, 1998 Aug, 64(8), 2966 - 9 Microbial dechlorination of 2,3,5,6-tetrachlorobiphenyl under anaerobic conditions in the absence of soil or sediment; Cutter L et al.; Bacterial enrichment cultures developed with Baltimore Harbor (BH) sediments were found to reductively dechlorinate 2,3,5, 6-tetrachlorobiphenyl (2,3,5,6-CB) when incubated in a minimal estuarine medium containing short-chain fatty acids under anaerobic conditions with and without the addition of sediment . Primary enrichment cultures formed both meta and ortho dechlorination products from 2,3,5,6-CB . The lag time preceding dechlorination decreased from 30 to less than 20 days as the cultures were sequentially transferred into estuarine medium containing dried, sterile BH sediment . In addition, only ortho dechlorination was observed following transfer of the cultures . Sequential transfer into medium without added sediment also resulted in the development of a strict ortho-dechlorinating culture following a lag of more than 100 days . Upon further transfer into the minimal medium without sediment, the lag time decreased to less than 50 days . At this stage all cultures, regardless of the presence of sediment, would produce 2,3,5-CB and 3,5-CB from 2,3,5,6-CB . The strict ortho-dechlorinating activity in the sediment-free cultures has remained stable for more than 1 year through several transfers . These results reveal that the classical microbial enrichment technique using a minimal medium with a single polychlorinated biphenyl (PCB) congener selected for ortho dechlorination of 2,3,5,6-CB . Furthermore, this is the first report of sustained anaerobic PCB dechlorination in the complete absence of soil or sediment. Appl Environ Microbiol, 1998 Aug, 64(8), 2920 - 4 A novel beta-N-acetylglucosaminidase from Streptomyces thermoviolaceus OPC-520: gene cloning, expression, and assignment to family 3 of the glycosyl hydrolases; Tsujibo H et al.; A beta-N-acetylglucosaminidase gene (nagA) of Streptomyces thermoviolaceus OPC-520 was cloned in Streptomyces lividans 66 . The nucleotide sequence of the gene, which encodes NagA, revealed an open reading frame of 1,896 bp, encoding a protein with an Mr of 66, 329 . The deduced primary structure of NagA was confirmed by comparison with the N-terminal amino acid sequence of the cloned beta-N-acetylglucosaminidase expressed by S . lividans . The enzyme shares no sequence similarity with the classical beta-N-acetylglucosaminidases belonging to family 20 . However, NagA, which showed no detectable beta-glucosidase activity, revealed homology with microbial beta-glucosidases belonging to family 3; in particular, striking homology with the active-site regions of beta-glucosidases was observed . Thus, the above-mentioned results indicate that NagA from S . thermoviolaceus OPC-520 is classified as a family 3 glycosyl hydrolase . The enzyme activity was optimal at 60 degreesC and pH 5.0, and the apparent Km and Vmax values for p-nitrophenyl-beta-N-acetylglucosamine were 425.7 microM and 24.8 micromol min-1 mg of protein-1, respectively. Appl Environ Microbiol, 1998 Aug, 64(8), 2814 - 21 Monitoring impact of a pesticide treatment on bacterial soil communities by metabolic and genetic fingerprinting in addition to conventional testing procedures; Engelen B et al.; Herbogil (dinoterb), a reference herbicide, the mineral oil Oleo (paraffin oil used as an additive to herbicides), and Goltix (metamitron) were taken as model compounds for the study of impacts on microbial soil communities . After the treatment of soil samples, effects on metabolic sum parameters were determined by monitoring substrate-induced respiration (SIR) and dehydrogenase activity, as well as carbon and nitrogen mineralization . These conventional ecotoxicological testing procedures are used in pesticide registration . Inhibition of biomass-related activities and stimulation of nitrogen mineralization were the most significant effects caused by the application of Herbogil . Even though Goltix and Oleo were used at a higher dosage (10 times higher), the application of Goltix resulted in smaller effects and the additive Oleo was the least-active compound, with minor stimulation of test parameters at later observation times . The results served as a background for investigation of the power of "fingerprinting" methods in microbial ecology . Changes in catabolic activities induced by treatments were analyzed by using the 95 carbon sources provided by the BIOLOG system . Variations in the complex metabolic fingerprints demonstrated inhibition of many catabolic pathways after the application of Herbogil . Again, the effects of the other compounds were expressed at much lower levels and comprised stimulations as well as inhibitions . Testing for significance by a multivariate t test indicated that the sensitivity of this method was similar to the sensitivities of the conventional testing procedures . The variation of sensitive carbon sources, as determined by factor weights at different observation times, indicated the dynamics of the community shift induced by the Herbogil treatment in more detail . DNA extractions from soil resulted in a collection of molecules representing the genetic composition of total bacterial communities . Distinct and highly reproducible community patterns, or genetic fingerprints, resulting from application of the different herbicides were obtained by the sequence-specific separation of partial 16S rDNA amplification products in temperature gradient gel electrophoresis . Significant pattern variations were quantified . For detailed analysis, application-responsive bands from the Herbogil and Oleo treatments were sequenced and their tentative phylogenetic positions were identified . Data interpretation and the potentials and biases of the additional observation windows on microbial communities are discussed. Biochim Biophys Acta, 1998 Aug 14, 1407(2), 135 - 45 Fibronectin-binding activity in Borrelia burgdorferi1; Grab DJ et al.; Recently, the term MSCRAMM (microbial surface components recognizing adhesive matrix molecules), has been introduced to describe microbial molecules that recognize extracellular matrix (ECM) {1} . Here we present evidence for the presence of fibronectin-binding molecules in Borrelia burgdorferi and several other Borrelia species . Immunofluorescence studies show that plasma fibronectin is bound uniformly over the cell surface of free swimming B . burgdorferi . In addition, the spirochetes are able to bind to plasma fibronectin-coated microwell plates, an interaction that is inhibited by anti-fibronectin antibody as well as exogenous plasma fibronectin . Taken together, the data suggest that fibronectin binds to the surface of the spirochete . On Western blot-like assays, B . burgdorferi and some B . afzelii strains express a major fibronectin-binding protein (Fn-BA) with an approximate molecular mass of 52 kDa . In addition, several other major Fn-BAs were found in B . hermsii (26, 31, 33, 39, 46, 54 and 58 kDa) and B . turicatae (39, 41, 45, 50, 56, 59 and 66 kDa) . Preliminary evidence suggests that fibronectin (and Fn-BA) may play a role as a molecular bridge between the spirochete and other components of the extracellular matrix. Acta Cytol, 1998 Jul-Aug, 42(4), 913 - 7 Pathologic outcome in HIV-seropositive individuals with nonspecific bronchoalveolar lavage cytology; Piller CF et al.; OBJECTIVE: To determine the pathologic outcome in human immunodeficiency virus (HIV)-seropositive individuals with nonspecific bronchoalveolar lavage (BAL) cytology . STUDY DESIGN: The study group consisted of 126 cytologically negative or nonspecific BAL specimens from HIV-seropositive adults . Concurrent microbial cultures and transbronchial biopsies, as well as subsequent pulmonary cytology, lung biopsy or autopsy results were reviewed . Additionally, the cytologic morphology of specimens from patients found to have a potential bacterial pathogen was reviewed . RESULTS: In the 126 cases with nonspecific BAL cytology, a potential pulmonary pathogen was identified from a concurrent or subsequent pathologic specimen in 27% of cases, while no pathogen was identified in 73% of cases . Bacteria and fungi were the most common pathogens identified . Microbial cultures alone identified the pathogen in 59% of cases, while transbronchial biopsy added information in only 9% . Specimens with marked acute inflammation often yielded bacterial pathogens on microbial culture . CONCLUSION: A potential pulmonary pathogen can be identified in 27% of HIV-seropositive individuals with negative BAL cytology using other diagnostic modalities . Bacterial pathogens are most common and are usually identified by microbial culture . Marked acute inflammation in a BAL specimen is often associated with bacterial pneumonia. Nutrition, 1998 Jul-Aug, 14(7-8), 641 - 7 Immunonutrition: the pediatric experience; Levy J; The health benefits of specific nutrients in the diet are reviewed as they pertain to the pediatric population and its unique needs . Secretory immunoglobulins, lysozyme, interferon, and growth factors, among others, are known to confer immunological advantages to breast milk . Inhibition of bacterial pathogens, as well as permissive growth of a protective colonic ecoflora occur as a result of various cellular and biochemical mechanisms at play . The immunomodulatory properties of minerals such as iron, zinc, and selenium, are presented and the newly recognized protective role of vitamin A and its importance in developing countries and in conditions of compromised nutrition are discussed . The review also covers the role of arginine, glutamine, and nucleotides in adaptive responses of the developing gut and in pathologic states such as necrotizing enterocolitis, short bowel syndrome, and inflammatory bowel disease . Probiotics (specific microbial feeds with potential benefits to the host), and prebiotics (dietary components such as complex carbohydrates able to change the colonic microenvironment fostering colonization with non-enteropathogens) are areas of current interest because they offer alternatives for the management of the growing problem of multiple antibiotic resistance and overwhelming infections in the hospitalized patient. CLAO J, 1998 Jul, 24(3), 145 - 51 Contact lens induced peripheral ulcers during hydrogel contact lens wear; Grant T et al.; PURPOSE: Ulcerative keratitis is the most serious adverse response associated with contact lens wear . However, some reports of microbial keratitis in the literature may refer to a less severe form of corneal ulceration, which we have termed contact lens induced peripheral ulcers (CLPU) . METHODS: We present details of 11 cases of CLPU which occurred in clinical trials at our research unit . RESULTS: CLPU episodes are characterized by a single, small (< 2 mm diameter) circular lesion in the corneal mid-periphery or periphery, involving a focal loss of the full thickness of the epithelium associated with subepithelial stromal infiltrates . Patient symptoms may include ocular irritation, pain, photophobia, and lacrimation . They are usually associated with the use of hydrogel extended wear contact lenses . The lesions are self-limiting, typically healing within 7 days without treatment . After resolution, a small circular scar remains, which does not affect vision because of its peripheral location . The etiology of CLPU is unclear . In our studies, the incidence of CLPU was similar in conventional (2.9% per patient year) and disposable (2.0% per patient year) hydrogel extended wear, but lower during intermittent extended wear (1.6% per patient year); only one case occurred during daily wear (< 0.5% per patient year) . CONCLUSIONS: A conservative approach to patient management of all suspected cases of corneal ulceration is encouraged . However, we suggest that future reports of ulcerative keratitis associated with various lens types and wearing schedules should differentiate between potentially devastating microbial keratitis and the relatively innocuous peripheral ulceration described in this paper. Mol Immunol, 1998 Jan, 35(1), 47 - 53 Alpha2-macroglobulin does not function as a C3 homologue in the plasma hemolytic system of the American horseshoe crab, Limulus; Armstrong PB et al.; A major problem of comparative immunology is the characterization of the internal defense systems that lyse foreign cells, such as bacteria and other microbial pathogens that have gained entry into the body . The plasma cytolytic system of the American horseshoe crab, Limulus polyphemus, is sensitive to treatment with methylamine, which inactivates the abundant plasma defense protein alpha2-macroglobulin . This has been interpreted to mean that alpha2-macroglobulin plays an important role in hemolysis, analogous to the role of complement component C3 of the mammalian complement system (Enghild et al., 1990) . Sensitivity to methylamine has been suggested to reflect an evolutionary homology with the plasma cytolytic system of mammals, in which the complement system is inactivated by the reaction of methylamine with complement components C3 and C4 . C3, C4 and alpha2-macroglobulin contain an internal thiol ester bond linking cysteinyl and glutamic acid residues and methylamine inactivates all three proteins by reaction with the thiol-esterified glutamic acid . However, we have recently shown that the principal effector of hemolysis in Limulus is the plasma lectin, limulin (Armstrong et al., 1996) . In this article we show that native, unreacted alpha2-macroglobulin is not involved directly in hemolysis but instead that methylamine-reacted alpha2-macroglobulin inhibits the hemolytic activity of limulin . Thus the thiol ester proteins alpha2-macroglobulin and C3 operate very differently in the hemolytic systems of Limulus and mammals and are not functionally homologous . Limulus alpha2-macroglobulin functions indirectly in hemolysis: its inactivation yields an inhibitory molecule for limulin-mediated hemolysis. Asian Pac J Allergy Immunol, 1998 Mar, 16(1), 31 - 41 Genetically engineered single-chain Fvs of human immunoglobulin against hepatitis C virus nucleocapsid protein derived from universal phage display library; Songsivilai S et al.; Specific single-chain Fvs (scFvs) of human immunoglobulin that specifically recognized the recombinant hepatitis C virus (HCV) nucleocapsid protein were isolated from a large phage display antibody library . This universal library of genetically engineered filamentous phagemids displayed random pairings of the variable regions of both human heavy and light chain immunoglobulin in the scFv format . Specific clones were isolated by affinity selection with purified recombinant HCV protein fused to glutathione-S-transferase (GST) . The GST-specific clones were excluded by blocking the phagemid library with GST prior to the selection . After 4 rounds of selection, the HCV-reactive clones were enriched by a factor of 100,000 . About 4% and 9% of the clones from rounds 4 and 5, respectively, specifically reacted to the HCV portion of the fusion protein in an enzyme immunoassay . The specificity was confirmed by specific binding inhibition with plasma from an HCV-infected individual . Nucleotide sequence analysis of 3 HCV-specific clones indicated that all 3 clones contained an almost identical VH gene sequence which was derived from the VH3 germline gene family . These clones had different VL gene sequences of the lambda type . There were some differences between nucleotide and amino acid sequences of the HCV-specific scFv genes and those of the closest matched germline genes, indicating the presence of somatic mutation . This study illustrated the feasibility of using antibody engineering technology with the universal phage display library to isolate human antibodies with predefined specificity to important microbial pathogen which may be useful for future therapeutic purpose. Plant J, 1998 Mar, 13(5), 673 - 83 Trehalose-6-phosphate phosphatases from Arabidopsis thaliana: identification by functional complementation of the yeast tps2 mutant; Vogel G et al.; It is currently thought that most flowering plants lack the capacity to synthesize trehalose, a common disaccharide of bacteria, fungi and invertebrates that appears to play a major role in desiccation tolerance . Attempts have therefore been made to render plants more drought-resistant by the expression of microbial genes for trehalose synthesis . It is demonstrated here that Arabidopsis thaliana itself possesses genes for at least one of the enzymes required for trehalose synthesis, trehalose-6-phosphate phosphatase . The yeast tps2 mutant, which lacks this enzyme, is heat-sensitive, and Arabidopsis cDNA able to complement this effect has been screened for . Half of the yeast transformants that grew at 38.6 degrees C were also able to produce trehalose . All of these expressed one of two Arabidopsis cDNA, either AtTPPA or AtTPPB, which are both homologous to the C-terminal part of the yeast TPS2 gene and other microbial trehalose-6-phosphate phosphatases . Yeast tps2 mutants expressing AtTPPA or AtTPPB contained trehalose-6-phosphate phosphatase activity that could be measured both in vivo and in vitro . The enzyme dephosphorylated trehalose-6-phosphate but not glucose-6-phosphate or sucrose-6-phosphate . Both genes are expressed in flowers and young developing tissue of Arabidopsis . The finding of these novel Arabidopsis genes for trehalose-6-phosphate phosphatase strongly indicates that a pathway for trehalose biosynthesis exists in plants. Cytogenet Cell Genet, 1998, 80(1-4), 138 - 41 Did the first adaptive immunity evolve in the gut of ancient jawed fish? Matsunaga T. Gut-associated immune tissue, as represented by lymphocytes and lymphoid cell aggregates, occurs in all jawed vertebrates . Considering the lymphopoietic function of the cryptopatches in the mouse intestine, the lymphoid aggregates in the gastrointestinal lamina propria of birds and cold-blooded vertebrates seem to serve the same function, thus providing an explanation for their conservation during a period of over 400 million years . Some gammadelta+ intraepithelial T cells are likely to develop and mature in gut-associated immune tissues . Intraepithelial gammadelta+ T cells may therefore have represented the first step in the evolution of adaptive immunity, reinforcing the gastrointestinal defense against microbial invasion as a result of increasing traumatization by injury and infection due to jaw development in host fish. J Biol Chem, 1998 Jul 31, 273(31), 19592 - 601 Functional changes in scavenger receptor binding conformation are induced by charge mutants spanning the entire collagen domain; Andersson L et al.; Macrophage scavenger receptors are trimeric integral membrane proteins that bind a diverse array of negatively charged ligands . They have been shown to play a role in the pathogenesis of atherosclerosis and in host responses to microbial infections . Earlier mutational studies demonstrated that the distal segment of the collagen domain of the receptor was critically important for high affinity ligand binding activity . In this study, mutations spanning the entire collagen domain were generated and binding was assayed in transfected cells, as well as in assays employing a secreted, receptor fusion protein . Many of the distal, positively charged C-terminal residues in the type II collagen domain of the receptor, previously reported to be essential for binding at 37 degreesC, were found not to be critical for binding at 4 degreesC . Conversely, more proximally charged residues of the collagen receptor that have not been previously mutated were shown to have substantial effects on binding that were also temperature-dependent . These data suggest that scavenger receptor ligand recognition depends on more complex conformational interactions, involving charged residues throughout the entire collagen domain, than was previously recognized. FEMS Microbiol Lett, 1998 Jul 1, 164(1), 187 - 93 Green fluorescent protein as a visual marker in a p-nitrophenol degrading Moraxella sp; Tresse O et al.; The green fluorescent protein gene (gfp) was introduced into a p-nitrophenol-metabolizing strain of Moraxella sp . by chromosomal integration . The gfp-marked transformants, designated Moraxella sp . strains G21 and G25, exhibited green fluorescence under UV light . Molecular characterization by PCR and Southern hybridization showed the presence of gfp in both transformants . Both transformants and the parent strain degraded 720 microM of p-nitrophenol with nitrite release within 4 h after inoculation in minimal medium supplemented with yeast extract . Transformants degraded up to 1440 microM p-nitrophenol and mineralized about 60% of 720 microM p-nitrophenol, both in broth and in soil, to the same extent as the parent strain . Insertion of gfp did not adversely affect the expression of p-nitrophenol-degrading genes in the transformants . Survival studies indicated that individual green fluorescent colonies of transformants can be detected up to 2 weeks after inoculation in soil . These marked strains could be of value in studies on microbial survival in the environment. Curr Opin Pulm Med, 1998 May, 4(3), 123 - 9 Bronchoscopy in the diagnosis of respiratory infections; Mares DC et al.; In recent years, several factors have altered the spectrum of respiratory infections and their likelihood of response to empiric treatment . Altered microbial resistance has led to the possible need for specific etiologic diagnosis in some hospital-acquired infections in the normal host . In the immune-compromised host, the spectrum of atypical presentations and unusual organisms limits the clinician's ability to choose effective empiric therapies . In the normal host, bronchoscopic diagnosis seems to be most useful in the groups with severe community-acquired pneumonia or poor response to therapy for community-acquired pneumonia . The group of patients with ventilator-associated pneumonia has been well-researched and the bronchoscopic techniques tend to show increased sensitivity over other diagnostic means, but this has not been proven to alter morbidity, mortality, or cost effectiveness . The immune-compromised host is commonly infected by organisms not easily diagnosed by other means and is thus unable to be treated empirically . Bronchoscopic diagnostic techniques play a larger and more clearly delineated role in these populations, including the patient populations with solid organ transplants, bone marrow transplants, and AIDS. Med Care, 1998 Jul, 36(7), 977 - 87 Relationship of provider characteristics to outcomes, process, and costs of care for community-acquired pneumonia; Whittle J et al.; OBJECTIVES: The authors describe the relation of provider characteristics to processes, costs, and outcomes of medical care for elderly patients hospitalized for community-acquired pneumonia . METHODS: Using Medicare claims data, Medicare beneficiaries discharged from Pennsylvania hospitals during 1990 with community-acquired pneumonia were identified . Claims data were used to ascertain mortality, readmissions, use of procedures and physician consultations, and the costs of care . The relationship of these measures to provider characteristics was analyzed using regression techniques to adjust for patient characteristics, including comorbidity and microbial etiology . RESULTS: Among 22,294 pneumonia episodes studied, 30-day mortality was 17.0% . After adjusting for patient characteristics, 30-day mortality and readmission rates were unrelated to hospital teaching status or urban location or to physician specialty . Use of procedures and physician consultations was more common and costs were 11% higher among patients discharged from teaching hospitals compared with nonteaching hospitals . Similarly, costs were 15% higher at urban hospitals compared with rural hospitals . General internists and medical subspecialists used more procedures and had higher costs than family practitioners . CONCLUSIONS: Processes and costs of care for community-acquired pneumonia varied by provider characteristics, but neither mortality nor readmission rates did . These differences cannot be explained by clinical variables in the database . Further studies should determine whether less costly patterns of care for pneumonia, and perhaps other conditions, could replace more costly ones without compromising patient outcomes. Can J Microbiol, 1998 Apr, 44(4), 394 - 8 The separation of alginate biosynthesis and acetylation in Pseudomonas syringae; Lee JW et al.; Seaweed alginate was acetylated by resting cells of Pseudomonas syringae subsp . phaseolicola ATCC 19304 . Physiological studies on this strain and its UV-induced mutants showed no correlation between bacterial alginate biosynthesis and acetylation . Specific yields of alginate and degree of acetylation in these polymers varied with strain and culture medium . This was indirect evidence that alginate biosynthesis is separate from polysaccharide acetylation . It indicated that the enzyme system involved in alginate biosynthesis was not directly linked to alginate acetylation and explained why microbial acetylation of seaweed alginates was possible. Arch Latinoam Nutr, 1997 Sep, 47(3), 224 - 8 {Microbial behavior and hurdles in Venezuelan intermediate moisture food}; Elguezabal L et al.; Sixteen Venezuelan IMF, dairy products, dry-salted fish products, meat products and vegetable products (specially fruit products) were characterized; water activity, pH, moisture, acidity and humectants were determined, allowing us to identify the main hurdles . Parallelly the microbial profile and her evolution for each IMF were established in function of time and storage conditions . This information permits us to explain the different stability compartments for our IMF; simple modifications that will increase their stability are suggested . Water activity is not enough as a hurdle if it is not accompanied by an appropriate packaging, specially in tropical countries, that would limit water migrations. Arch Latinoam Nutr, 1997 Sep, 47(3), 208 - 16 {Microbial and enzymatic extraction of pectin . A review}; Contreras-Esquivel JC et al.; Great amounts of agroindustrial wastes rich in polysaccharides, such as pectic substances, are produced worldwide . Some of these wastes are used for the production of pectin . Currently, pectin is extracted at industrial scale by physicochemical means, but lately new biotechnological alternatives have been developed . In this review, the principal characteristics of pectic substances and pectic enzymes are described . The traditional physicochemical method for the pectin extraction is described and the new biotechnological (microbial and enzymatic) methods for pectin extraction are discussed and commented as well. J Clin Lab Anal, 1998, 12(4), 238 - 41 Evaluation of PCR assays in presence of antibody to thermostable DNA polymerases for detection of microbial agents: avoiding false negative results for specimen containing low-titer agent; Poddar SK et al.; The serial low-titer specimens of Influenza A virus and Adeno virus type 7 were tested for the presence of virus specific genes by PCR based on Tth DNA polymerase and by that based on Taq DNA polymerase, in the absence and presence of antibody to the respective DNA polymerases . Increased product DNA synthesis and higher sensitivity of detection were observed in the presence of antibody compared to those in the absence of antibody . 10- to 100- fold lower titer specimen of Influenza A virus and 10-fold lower titer specimen of Adeno virus could be detected in the presence of antibody than those detected in the absence of antibody to the appropriate DNA polymerase, in a PCR. Respiration, 1998, 65(3), 211 - 3 Repeated pulmonary infection by Nocardia asteroides complex in a patient with bronchiectasis; Cremades MJ et al.; A rare case of pulmonary nocardiosis was presented in a nonimmunocompromised patient who had chronic airway obstruction and bronchiectasis without corticoid treatment . The microbial diagnosis was established after isolating Nocardia in bronchial aspirate and sputum samples . An in vitro study showed sensitivity only to imipenem, netilmicine, amikacin and ofloxacin . The evolution was chronic, with multiple clinical recurrences in spite of prolonged antibiotic treatment . Finally, the eradication of Nocardia was achieved with the combination of imipenem and amikacin. Acta Odontol Scand, 1998 Apr, 56(2), 90 - 4 Polyol-combinant saliva stimulants: a 4-month pilot study in young adults; Makinen KK et al.; Several studies indicate that xylitol (X) consumption is associated with certain biochemical changes in dental plaque and whole saliva . In making X-containing saliva stimulants more cost-effective and palatable, manufacturers may use maltitol syrup (MS, which normally contains some sorbitol and higher polyols) or polydextrose (PD, a polysaccharide molecule with a mass > 22 kDa) as bulking agents . Combinations of X with MS and PD have not been tested regarding their salivary effects . One hundred and eighty-eight young subjects (mean age, 22 years) of both sexes were divided into three groups of equal size for a 4-month study . The subjects in one group used X-MS dragees (in 7 daily episodes; 8 g X per day), while the subjects in another group used X-PD dragees in as many daily episodes (8 g X per day) . Subjects in the third (comparison) group did not receive saliva stimulants . Paraffin-stimulated whole saliva samples were collected at baseline, after 2 months, and at endpoint . The usage of X-MS was associated with a significant (P < 0.05) reduction in the salivary sucrase activity . After 4 months, the activity of enzymes hydrolyzing N(alpha)-benzoyl-DL-arginyl-p-nitroaniline was significantly reduced in all groups, while the levels of free sialic acid were reduced in group X-PD only (P < 0.05) . These salivary changes most likely reflected microbial shifts in the oral cavity and suggest that information from saliva studies may be of avail when deciding which bulking agents should be used in xylitol-based saliva stimulants. Curr Opin Chem Biol, 1998 Feb, 2(1), 77 - 84 Microbial transformations; Holland HL; Although the use of microbial biocatalysts for chemical reactions pre-dates by a considerable margin the application of isolated enzymes for this purpose, considerable progress continues to be made in the use of whole-cell catalysts . The application of whole-cell biocatalysts in oxygenase-catalysed reactions, the reductions of carbonyl and nitro groups, and the hydrolysis of nitriles and epoxides, are all areas of continued development . In addition, the use of microbial transformations in the production of drug metabolites, carbohydrates, and amino acids is expanding . Methodological development such as the application of novel immobilisation techniques or the use of non-aqueous solvents continues to enhance the usefulness of microbial biocatalysts. Br J Rheumatol, 1998 Jun, 37(6), 602 - 11 A fistful of T cells; Moots RJ; Evidence incriminating T cells in rheumatoid arthritis (RA) is strong but circumstantial--like a smoking gun at the scene of a crime . To investigate this, T lymphocytes were studied in health and disease . The effect of mutations in the groove of HLA-A2 on peptide presentation to T cells was studied to investigate normal T cell function . This allowed a detailed description of the interactions between individual MHC residues and antigens . Subsequently, T cells in the autoimmune disease, multiple sclerosis, were studied, to investigate the mechanisms for breakdown in peripheral tolerance . T-cell clones that recognized both autoantigens and viral proteins were isolated, suggesting that infection may trigger disease . Autoantigens would need to be defined to use this strategy in RA . T-cell responses to type II collagen, a candidate auto-antigen, were therefore studied in RA and an epitope successfully defined . The search for microbial 'mimics' triggering RA, and novel forms of immunotherapy are now possible--with potential rehabilitation of T cells. J Antibiot (Tokyo), 1998 May, 51(5), 480 - 6 Effect of a novel antibiotic, heliquinomycin, on DNA helicase and cell growth; Chino M et al.; Heliquinomycin, a novel microbial product, was found to inhibit a human DNA helicase enzyme isolated from HeLa S3 cells at concentrations of 5 to 10 micrograms/ml . In contrast, adriamycin, etoposide and cisplatin did not inhibit this enzyme at the concentrations tested . Furthermore, the replication and repair of SV40 chromosome were not affected at heliquinomycin concentration of 50 micrograms/ml . The topoisomerase II and I enzymes were inhibited at 30 micrograms/ml and 100 micrograms/ml of heliquinomycin, respectively . Heliquinomycin inhibited the growth of HeLa S3, KB, LS180, K562 and HL60 human tumor cell lines at IC50 values of 0.96 to 2.8 micrograms/ml . In addition, the growth of adriamycin and cisplatin resistant P388 cell lines were inhibited at similar concentrations . Heliquinomycin inhibited both DNA and RNA synthesis in cell culture but did not inhibit protein synthesis . HeLa S3 cells were arrested at the G2/M phase by heliquinomycin . These studies suggest that heliquinomycin is a selective inhibitor of a cellular DNA helicase and in turn, inhibits growth of tumor cell lines. Gene, 1998 Jul 17, 215(1), 203 - 12 Characterization and functional analysis of the porcine lactoferrin gene promoter; Wang SR et al.; Lactoferrin, a ferric binding glycoprotein found in milk, can possibly prevent microbial infection of the mammary gland and gastrointestinal tract . To define the regulation of the porcine lactoferrin gene (pLTF), we cloned its 5'-flanking region from a porcine liver genomic library and analyzed the 5' upstream region of approx . 4kb, two exons, and an intron . The transcription start site was localized by primer extension to residue G, which is 41 nucleotides upstream from the ATG start codon . The pLTF 5'-flanking region possesses several putative cis-acting regulatory elements found in both housekeeping and inducible genes; to define their function, they were inserted into a chloramphenicol acetyltransferase reporter construct . The region up to -156 sufficed for basic promoter activity, whereas the region up to -780 was required for maximal promoter activity in porcine testis cells (STcells), kidney cells (PK15 cells) and human mammary epithelial cells (HBL-100 cells) . Detailed analysis of this proximal region by DNase I footprinting and electrophoretic mobility shift assays reveals that the ubiquitous factors SP1, AP2 and the mammary gland-specific factor (MGF) might play significant roles in regulating the transcription of the pLTF gene. J Dent Res, 1998 Jul, 77(7), 1547 - 52 The effects of xylitol-containing chewing gums on dental plaque and acidogenic potential; Scheie AA et al.; The aim of this study was to test the hypothesis that the chewing of xylitol- or xylitol/sorbitol-containing chewing gum reduces plaque formation and the acidogenic potential of dental plaque . Thirty healthy volunteers aged from 19 to 28 yrs were randomly allocated to one of three test groups, chewing either xylitol-, xylitol/sorbitol-, or sucrose-sweetened gums . A three-day plaque accumulation period of no oral hygiene was instituted prior to and at the termination of the chewing gum program, which lasted 33 days . Plaque quantity was assessed on the basis of protein content of individual plaque samples collected by a standardized technique . Acidogenic potential of individual baseline and test plaque samples was assessed by the quantity of various organic acids formed from D-(U-14C)glucose . Identification of extracellular and intracellular metabolites was performed by HPLC . Statistical evaluation of data was performed according to paired comparisons of individual baseline and post-chewing data . Plaque formation, acidogenic potential, and glycolytic profiles were similar at baseline and after the gum-chewing periods . Also, there was no intracellular accumulation of glycolytic metabolites within the plaque bacteria to indicate the inhibition of glycolysis . The study thus leads to the conclusion that, in young adults with low caries experience, exposure of the oral cavity to acceptable doses of xylitol or xylitol and sorbitol has no effect on the microbial deposits on the teeth. Pediatr Med Chir, 1998 Jan-Feb, 20(1), 13 - 7 {Probioticss, prebiotics,synbiotics and eubiotics}; Zoppi G; The Author summarizes the most widely definitions of agents affecting the intestinal ecosystem . Probiotic is a live microbial feed which beneficially affects the intestinal microbial balance . Prebiotic is a non digestible food which improves the growth of bacteria in the colon . Synbiotic or eubiotic is a mixture of probiotics and prebiotics. Prim Dent Care, 1998 Apr, 5(2), 69 - 72 Biocompatibility of dentine-bonding agents . 2 . Pulpal considerations; Santini A; The paper reviews the literature concerning the biocompatibility of dentine-bonding agents . The literature review indicates that two main hypotheses are presented to explain pulpal inflammation following the placement of materials such as dentine-bonding agents, namely material toxicity and bacterial infection . The paper discusses the role of such factors as microbial microleakage, remaining dentine thickness and the smear layer as factors in determining material toxicity and summarises the reported biocompatibility studies . From this it is concluded that most bonding agents contain constituents which have a potential irritant or toxic effect on the pulpo-dentinal complex . The irritant effect may be due to constituents of the bonding agents, or to poor or lost bonding, or to a combination of all these factors . The recently favoured total-etch technique may cause an increase in dentine permeability by removal of the smear layer and thereby increase the irritant effect of some materials. Perit Dial Int, 1997 Nov-Dec, 17(6), 560 - 7 Touch contamination of connection devices in peritoneal dialysis--a quantitative microbiologic analysis; Miller TE et al.; OBJECTIVE: To determine the level of bacterial contamination associated with touch contact of a connector set during peritoneal dialysis (PD) . DESIGN: The experiment utilized a laboratory-based simulation of a bag exchange procedure . Deliberate touch contamination of the connector set spike was followed by quantitative recovery of micro-organisms from the connector and, in some cases, the dialysis bag . SUBJECTS: Patients undergoing PD were used as the "test" group . Departmental secretarial and laboratory staff served as the comparative control group . SETTING: The patients were voluntary subjects from a PD outpatients unit and were tested in their own homes . OUTCOME: The numbers of micro-organisms contaminating a connector set and entering the dialysis bag during a touch-contamination event were determined . Additionally we identified hand hygiene and, in particular, the care taken to dry the hands after washing as being highly relevant to microbial touch-contamination levels . Patient hand disinfection, as practised in most PD units, effectively reduced touch contamination to low levels . RESULTS: Touch contamination of a connector set with unprepared hands led to fewer than 100 micro-organisms translocating from fingers to the spike . If the hands were washed but not dried before touch contact was made, up to 4500 micro-organisms translocated to the connector set spike . Air-towel drying of washed hands be