Immunochemical study of the antigenic structure of bacteria of genus Bordetella. IV. Fractionation of B. pertussis extracts and study of the immunochemical and biological properties of the isolated fractions]

Fractionation of an extract of pertussis microbes was carried out with the aid of gel-filtration on Sephadex G-100, ion-exchange chromatography on DEAE-cellulose, and preparative electrophoresis. Fractions differing in serological, immunogenic activity and the content of antigenic components were isolated. In using the method of gel-filtration of sefadex G-100 the greatest serological, immunogenic and histamine-sensitizing activity was possessed by the high-molecular fraction containing 8 of 11 antigenic components detected in the initial extract. The antigenic components were distributed into 5 fractions by the ion exchange chromatography on DEAE-cellulose. The greatest serological activity was possessed by fractions exiting from the column at the 0.01--0.04M interval of the phosphate buffer concentration. A method of preparative electrophoresis from the pertussis microbes extract was applied and two fractions were isolated from the anode and the cathode zones, each containing 4 antigenic components only, but possessing serological and immunogenic activity and having no histamine-sensitizing properties.     

Shared themes of antigenic variation and virulence in bacterial, protozoal, and fungal infections.

Pathogenic microbes have evolved highly sophisticated mechanisms for colonizing host tissues and evading or deflecting assault by the immune response. The ability of these microbes to avoid clearance prolongs infection, thereby promoting their long-term survival within individual hosts and, through transmission, between hosts. Many pathogens are capable of extensive antigenic changes in the face of the multiple constitutive and dynamic components of host immune defenses. As a result, highly diverse populations that have widely different virulence properties can arise from a single infecting organism (clone). In this review, we consider the molecular and genetic features of antigenic variation and corresponding host-parasite interactions of different pathogenic bacterial, fungal, and protozoan microorganisms. The host and microbial molecules involved in these interactions often determine the adhesive, invasive, and antigenic properties of the infecting organisms and can dramatically affect the virulence and pathobiology of individual infections. Pathogens capable of such antigenic variation exhibit mechanisms of rapid mutability in confined chromosomal regions containing specialized genes designated contingency genes. The mechanisms of hypermutability of contingency genes are common to a variety of bacterial and eukaryotic pathogens and include promoter alterations, reading-frame shifts, gene conversion events, genomic rearrangements, and point mutations.     

Microbial subpopulations in the biofilm attached to the substratum and in the free flocs of a fixed-bed anaerobic bioreactor

The microbial flora of a fixed-bed anaerobic methanogenic bioreactor fed with acetate/propionate/butyrate was studied by direct, qualitative and quantitative methods avoiding culture isolation. The aims were to identify species, determine the distribution of microbes between the biofilm attached to the substratum and the free flocs, and define the acidogenic, acetogenic and methanogenic contingents. Optical and scanning electron microscopies showed heterogeneous assemblies of microbes in the biofilm and flocs, which were confirmed by antigenic fingerprinting. A diversity of species involved in the three phases of methanogenesis was detected, and most of these species were antigenically different from the reference organisms. Some microbial subpopulations identified by antigenic fingerprinting changed in size within an interval of 3 weeks, i.e. they either increased or decreased their concentrations by at least tenfold, while others remained relatively constant. The total cell concentration in the flocs was lower than in the biofilm, but at least one microbial subpopulation was more concentrated in the former than in the latter, indicating a preference of location between the compartments available within the bioreactor.Dedicated to Professor Dr. Hans Diekmann on the occasion of his 65th birthday     

Use of hybrid strains of S, typhi and S. typhimurium for characterizing the biological activity of individual Salmonella antigens by the alternative recording of the experimental results]

Intraperitoneal infection of mice, subcutaneously immunized with acetone vaccines of various antigenic composition, with the microbes of hybrid salmonellae strains of murine and typhoid fever caused development of infectious process approaching natural infection. A significant elevation of the intensity of immunity was provided by preparations containing serologically identical O-antigen in infection with O-strains, or Vi-antigen in infection with Vi-strains. For the formation of animal resistance to infection it was necessary to immunize the mice with vaccines containing homologous H- and O-antigens (in infection with O-strains) and H-, O- and Vi-antigens (in infection with Vi-strains). Immunization with killed vaccines with a full-value antigenic structure provided effective protection of mice from doses approaching LD50.     

PolysacDB: a database of microbial polysaccharide antigens and their antibodies

Vaccines based on microbial cell surface polysaccharides have long been considered as attractive means to control infectious diseases. To realize this goal, detailed systematic information about the antigenic polysaccharide is necessary. However, only a few databases that provide limited knowledge in this area are available. This paper describes PolysacDB, a manually curated database of antigenic polysaccharides. We collected and compiled comprehensive information from literature and web resources about antigenic polysaccharides of microbial origin. The current version of the database has 1,554 entries of 149 different antigenic polysaccharides from 347 different microbes. Each entry provides comprehensive information about an antigenic polysaccharide, i.e., its origin, function, protocols for its conjugation to carriers, antibodies produced, details of assay systems, specificities of antibodies, proposed epitopes involved and antibody utilities. For convenience to the user, we have integrated web interface for searching, advanced searching and browsing data in database. This database will be useful for researchers working on polysaccharide-based vaccines. It is freely available from the URL: http://crdd.osdd.net/raghava/polysacdb/.     

Membrane antigens of the agents of glanders and melioidosis]

Double immunodiffusion in gel test was used to determine the antigenic composition of the preparations of membranes isolated from the lysozyme spheroplasts of glanders (strain No. 10230) and melioidosis (strain No. C-141) causative agents. The membranes of these microbes proved to contain antigens of cell walls, lipopolysaccharides and the thermolabile membrane antigen proper. A study of antimembrane sera in the agglutination and immunofluorescence tests demonstrated a heterogeneity of the glanders and melioidosis strains under study by the membrane thermolabile antigen.     

Why are parasite contingency genes often associated with telomeres?

Contingency genes are common in pathogenic microbes and enable, through pre-emptive mutational events, rapid, clonal switches in phenotype that are conducive to survival and proliferation in hosts. Antigenic variation, which is a highly successful survival strategy employed by eubacterial and eukaryotic pathogens, involves large repertoires of distinct contingency genes that are expressed differentially, enabling evasion of host acquired immunity. Most, but not all, antigenic variation systems make extensive use of subtelomeres. Study of model systems has shown that subtelomeres have unusual properties, including reversible silencing of genes mediated by proteins binding to the telomere, and engagement in ectopic recombination with other subtelomeres. There is a general theory that subtelomeric location confers a capacity for gene diversification through such recombination, although experimental evidence is that there is no increased mitotic recombination at such loci and that sequence homogenisation occurs. Possible benefits of subtelomeric location for pathogen contingency systems are reversible gene silencing, which could contribute to systems for gene switching and mutually exclusive expression, and ectopic recombination, leading to gene family diversification. We examine, in several antigenic variation systems, what possible benefits apply.     

Analyzing the joint effects of two antibodies and the design of molecularly engineered vaccines

A new analytical approach to determine how antibodies relate to each other in producing immunity is presented. One purpose of this analysis is to decide on the antigenic composition of vaccines. Regression analyses and single discrete analyses are shown to be inappropriate to this task. The proposed analyses makes multiple cut points on two pre-exposure antibody levels. At each resulting discrete classification, additive and multiplicative interaction parameters are calculated. Various models of joint antibody action are shown to produce two general patterns of interaction terms with this type of analysis. One pattern characterizes situations where each antibody, or something substituting for the action of each antibody, is always needed to eliminate all infections. This may be because the antigens to which the antibodies are directed are on separate microbes or because microbes can only be neutralized by the joint action of both antibodies. A second pattern characterizes situations where both antibodies act cooperatively but given high enough levels only one may be needed. This may be because the antibodies have the same molecular effect or because they act by separate means against the same organisms in an innoculum.     

Origin of plague moderate phages of serotype 2]

Results of study of the negative colonies morphology, the structure of corpuscles, antigenic properties, specificity, and the action range permitted to refer the phages obtained from 18 E. coli strain, 1 plaque strain, and 1 pseudotoberculosis bacillus strain to the same group and to identify them with plague phages of serological type 2. Isolation of the same phage type from different bacterial species permits to regard them as "polyhostal" ones. E. coli should be considered as the main carrier of phages belonging to serological type 2. It is suggested that phages existing on microbes belonging to different species should be called "polyhostal".     

Galectin-9 recognizes and exhibits antimicrobial activity toward microbes expressing blood group–like antigens

While adaptive immunity recognizes a nearly infinite range of antigenic determinants, immune tolerance renders adaptive immunity vulnerable to microbes decorated in self-like antigens. Recent studies suggest that sugar-binding proteins galectin-4 and galectin-8 bind microbes expressing blood group antigens. However, the binding profile and potential antimicrobial activity of other galectins, particularly galectin-9 (Gal-9), has remained incompletely defined. Here, we demonstrate that while Gal-9 possesses strong binding preference for ABO(H) blood group antigens, each domain exhibits distinct binding patterns, with the C-terminal domain (Gal-9C) exhibiting higher binding to blood group B than the N-terminal domain (Gal-9N). Despite this binding preference, Gal-9 readily killed blood group B–positive Escherichia coli, whereas Gal-9N displayed higher killing activity against this microbe than Gal-9C. Utilization of microarrays populated with blood group O antigens from a diverse array of microbes revealed that Gal-9 can bind various microbial glycans, whereas Gal-9N and Gal-9C displayed distinct and overlapping binding preferences. Flow cytometric examination of intact microbes corroborated the microbial glycan microarray findings, demonstrating that Gal-9, Gal-9N, and Gal-9C also possess the capacity to recognize distinct strains of Providencia alcalifaciens and Klebsiella pneumoniae that express mammalian blood group–like antigens while failing to bind related strains that do not express mammalian-like glycans. In each case of microbial binding, Gal-9, Gal-9N, and Gal-9C induced microbial death. In contrast, while Gal-9, Gal-9N, and Gal-9C engaged red blood cells, each failed to induce hemolysis. These data suggest that Gal-9 recognition of distinct microbial strains may provide antimicrobial activity against molecular mimicry.     

S9A Serine Protease Engender Antigenic Gluten Catabolic Competence to the Human Gut Microbe

The human gut microbiome has a significant role in host physiology; however its role in gluten catabolism is debatable. Present study explores the role of human gut microbes in gluten catabolism and a native human gut microbe Cellulomonas sp. HM71 was identified. SSU rDNA analysis has described human gut microbiome structure and also confirmed the permanent residentship of Cellulomonas sp. HM71. Catabolic potential of Cellulomonas sp. HM71 to cleave antigenic gluten peptides indicates presence of candidate gene encoding biocatalytic machinery. Genome analysis has identified the presence of gene encoding S9A serine protease family—prolyl endopeptidase, with Ser591, Asp664 and His685 signature residues. Cellulomonas sp. HM71 prolyl endopeptidase activity was found optimal at pH 7.0 and 37 °C with a K_M of 35.53 μmol and specifically cleaves at proline residue. Current study describes the gluten catabolism potential of Cellulomonas sp. HM71 depicting possible role of human gut microbes in gluten catabolism to confer resistance mechanisms for the onset of celiac diseases in populations with gluten diet.     

病毒与细胞的微生态学研究进展

微生态学（microecology）是细胞水平或分子水平的生态学,它是研究微生物群的结构和功能,以及微生物与其宿主相互依赖、相互制约关系的科学。病毒（virus）是一种比细菌还要微小和简单的非细胞形态微生物（acellular microorganism）,不仅可寄生于动植物体的组织细胞表面或内部,还可寄生于细菌、真菌等微生物内部。作为宿主以及细胞内的寄生体,病毒除引起宿主多种类型的感染外,还可参与宿主组织细胞的微生态系的组成,赋予细胞干扰相关病毒增殖与复制、抵抗特定病毒感染感染的作用,并能引起宿主细胞产生特定毒素、获得新抗原性等改变。本研究通过微生态学角度,对病毒与细胞的相互关系及病毒与细胞微生态学在医学上的作用作一综述。     

An immunodominant conserved region within the variable domain of VlsE, the variable surface antigen of Borrelia burgdorferi.

Antigenic variation is an effective strategy evolved by pathogenic microbes to avoid immune destruction. Variable Ags such as the variable major protein of Borrelia hermsii, the variant surface glycoprotein of African trypanosomes, and the pilin of Neisseria gonorrhoeae include an immunodominant variable domain and one or more invariable domains that are not antigenic. Short, nonantigenic, invariable regions also may be present within the variable domain. VlsE (variable major protein-like sequence, expressed), the variable surface Ag of Borrelia burgdorferi, the Lyme disease spirochete, also contains both variable and invariable domains. In addition, interspersed within the VlsE variable domain there are six invariable regions (IR1-6) that together amount to half of this portion's primary structure. We show here that these IRs are conserved among strains and genospecies of the B. burgdorferi sensu lato complex. Surprisingly, unlike the invariable regions of variable major protein, variant surface glycoprotein, and pilin, which are not antigenic in natural infections, the most conserved of the IRs, IR6, is immunodominant in Lyme disease patients and in monkeys infected with B. burgdorferi. IR6 is exposed on the surface of VlsE, as assessed by immunoprecipitation experiments, but is inaccessible to Ab on the spirochete's outer membrane, as demonstrated by immunofluorescence and in vitro killing assays. VlsE thus significantly departs from the antigenic variation paradigm, whereby immunodominance is only manifest in variable portions. We submit that IR6 may act as a decoy epitope(s) and contribute to divert the Ab response from other, perhaps protective regions of VlsE.     

普洱茶后发酵过程中微生物的研究进展

对有关普洱茶后发酵生产与微生物的关系、微生物的种类、微生物对普洱茶品质的影响以及主要微生物的生长特性等方面的研究工作进行综述。指出加强普洱茶后发酵过程中微生物基础研究的必要性,提出建立普洱茶后发酵菌物库,重视对影响普洱茶品质的菌物开展系统研究的建议。     

Direct Characterization of Methanogens in Two High-Rate Anaerobic Biological Reactors

The methanogenic flora from two types of turbulent, high-rate reactors was studied by immunologic methods as well as by phase-contrast, fluorescence, and scanning electron microscopy. The reactors were a fluidized sand-bed biofilm ANITRON reactor and an ultrafiltration membrane-associated suspended growth MARS reactor (both trademarks of Air Products and Chemicals, Inc., Allentown, Pa.). Conventional microscopic methods revealed complex mixtures of microbes of a range of sizes and shapes, among which morphotypes resembling Methanothrix spp. and Methanosarcina spp. were noticed. Precise identification of these and other methanogens was accomplished by antigenic fingerprinting with a comprehensive panel of calibrated antibody probes of predefined specificity spectra. The methanogens identified showed morphotypes and antigenic fingerprints indicating their close similarity with the following reference organisms: Methanobacterium formicicum MF and Methanosarcina barkeri W in the ANITRON reactor only; Methanosarcina barkeri R1M3, M. mazei S6, Methanogenium cariaci JR1, and Methanobrevibacter arboriphilus AZ in the MARS reactor only; and Methanobrevibacter smithii ALI and Methanothrix soehngenii Opfikon in both reactors. Species diversity and distribution appeared to be, at least in part, dependent on the degree of turbulence inside the reactor.     

Study of the properties of E. coli of serological group 03 isolated in acute intestinal diseases]

The authors studied the properties of 115 strains of E. coli of serological group 03 isolated from 49 children and adults with acute intestinal disturbances. The majority of the children (82.9%) were aged under one year. Results of the study of the antigenic structure and biochemical properties permitted to differentiate the strains isolated into 3 serological types, with the prevalence of strains of type O3 : K2 (L) : H2 (78.3%), and 8 biochemical variants. The majority of the strains possessed hemolytic properties. Strains of serological group O3 were isolated repeatedly from the patients during the sickness, whereas none were revealed in examination of 132 healthy children and adults. The data obtained permitted to consider these microbes to be possible causative agents of intestinal coliinfection, and to refer them to the enteropathogenic category.     

Indicator microbes correlate with pathogenic bacteria, yeasts and helminthes in sand at a subtropical recreational beach site

Aims: Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non‐point source subtropical marine beach. Methods and Results: In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use. Conclusions: Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin‐resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non‐point source beaches. Significance and Impact of the Study: The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non‐point sources beaches.     

The contributing role of the intestinal microbiota in stressor-induced increases in susceptibility to enteric infection and systemic immunomodulation

This article is part of a Special Issue "Neuroendocrine-Immune Axis in Health and Disease." The body is colonized by highly complex and genetically diverse communities of microbes, the majority of which reside within the intestines in largely stable but dynamically interactive climax communities. These microbes, referred to as the microbiota, have many functions that enhance the health of the host, and it is now recognized that the microbiota influence both mucosal and systemic immunity. The studies outlined in this review demonstrate that the microbiota are also involved in stressor-induced immunomodulation. Exposure to different types of stressors, including both physical and psychological stressors, changes the composition of the intestinal microbiota. The altered profile increases susceptibility to an enteric pathogen, i.e., Citrobacter rodentium, upon oral challenge, but is also associated with stressor-induced increases in innate immune activity. Studies using germfree mice, as well as antibiotic-treated mice, provide further evidence that the microbiota contribute to stressor-induced immunomodulation; stressor-induced increases in splenic macrophage microbicidal activity fail to occur in mice with no, or reduced, intestinal microbiota. While the mechanisms by which microbiota can impact mucosal immunity have been studied, how the microbiota impact systemic immune responses is not clear. A mechanism is proposed in which stressor-induced degranulation of mucosal mast cells increases the permeability of the intestines. This increased permeability would allow intact bacteria and/or bacterial products (like peptidoglycan) to translocate from the lumen of the intestines to the interior of the body, where they directly, or indirectly, prime the innate immune system for enhanced reactivity to antigenic stimulation.     

脊髓灰质炎病毒重组体的构建及其抗原性状分析

以脊髓灰质炎病毒（以下简称脊灰病毒）为载体构建的重组体活病毒可以做为探讨脊灰病毒的抗原结构和特性的有益手段。在构建重组有甲型肝炎病毒小片段抗原多肽的重组脊灰病毒基础上,分析了脊灰病毒VP1上中和抗原位点I的空间构象特点,并探讨了插入的外源抗原片段对其空间结构的可能影响。