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PubMed2026

Whole genome sequencing and phenotypic characterization of microbial isolates associated with two Floridian fig species.

Fig-associated microbes are increasingly recognized as important contributors to the ecology of fig ( Ficus ) communities, yet few cultured isolates are available for functional investigation. Students enrolled in a course-based undergraduate research experience (CURE) phenotypically characterized and generated high-quality genome assemblies for 22 bacterial isolates recovered from Ficus aurea and Ficus citrifolia in southern Florida, USA. These isolates represent six bacterial species spanning four genera and provide a genomic resource for future investigations of microbial interactions within fig communities.

Journal Article↗
PubMed2026

Immunological, Inflammatory, and Microbiota Determinants of Carpal Tunnel Syndrome: Evidence from Mendelian Randomization.

INTRODUCTION: Carpal Tunnel Syndrome (CTS) is a common peripheral neuropathy, and immune dysregulation and microbial dysbiosis are believed to play a role in its development. However, the cause-and-effect relationships have yet to be clarified. METHODS: Using publicly available Genome-Wide Association Study (GWAS), there are 731 immune cell phenotypes, 91 inflammatory proteins, 150 skin microbiota taxon, and 473 gut microbiota taxon based on two-sample Mendelian Randomization (MR) analysis to test whether there is a causal relationship between them and CTS. The results from the study were shown to have some degree of stability as demonstrated by various sensitivity analyses, which included running heterogeneity tests, performing MR -PRESSO, and running MR-Egger regressions. On the other hand, reverse MR was performed to verify the direction of the association. In addition, a two-step MR mediation analysis was conducted to explore whether there was a mediation effect of gut microbiota and skin microbiota, respectively, of immune and inflammatory traits on CTS. RESULTS: 22 Immune cell traits, 4 Inflammatory proteins, 18 gut microbiota taxa, and 3 skin microbiota taxa are causally associated with CTS. Reverse MR suggested feedback effects of CTS on select immune traits and gut microbiota. Mediation analysis revealed 4 gut microbiota taxa that substantially mediated immune/inflammatory effects upon CTS, with mediation rates as high as 44%; however, skin microbiota did not demonstrate any mediation. DISCUSSION: The immune dysregulation, inflammation, and the gut microbiota that cause CTS are all revealed through this research. Mendelian randomization analysis suggests that traits and inflammatory proteins of immune cells directly increase the risk of CTS, and certain types of gut microbes partially mediate these effects. Therefore, the results show a central role of the immune-gut axis in CTS pathogenesis, and suggest a systemic, rather than a local, immune-microbial interaction in disease development. CONCLUSION: We provided the first causal evidence that immune cells, inflammatory proteins, and CTS risk are causally associated with some specific taxa of gut microbiota. This contributes to a better understanding of the immune-microbiome interactions in the process of occurrence and development of CTS, and also provides theoretical support for precision prevention and treatment.

Humans↗
PubMed2000

Membrane cofactor protein (MCP; CD46): isoform-specific tyrosine phosphorylation.

Membrane cofactor protein (MCP; CD46) is a widely expressed type 1 transmembrane glycoprotein that inhibits complement activation on host cells. It also is a receptor for several pathogens including measles virus, Streptococcus pyogenes, Neisseria gonorrhea, and Neisseria meningitidis. That MCP may have signaling capability was suggested by its microbial interactions. That is, binding of MCP on human monocytes by measles virus hemagglutinin or cross-linking by an anti-MCP Ab resulted in IL-12 down-regulation, while binding to MCP by Neisseria on epithelial cells produced a calcium flux. Through alternative splicing, MCP is expressed on most cells with two distinct cytoplasmic tails of 16 (CYT-1) or 23 (CYT-2) amino acids. These play pivotal roles in intracellular precursor processing and basolateral localization. We investigated the putative signal transduction pathway mediated by MCP and demonstrate that CYT-2, but not CYT-1, is phosphorylated on tyrosine. We examined MCP tail peptides and performed Ab cross-linking experiments on several human cell lines and MCP isoform transfectants. We found an MCP peptide of CYT-2 was phosphorylated by a src kinase system. Western blots of the cells lines demonstrated that cells bearing CYT-2 were also phosphorylated on tyrosine. Additionally, we provide genetic and biochemical evidence that the src family of kinases is responsible for the latter phosphorylation events. In particular, the src kinase, Lck, is required for phosphorylation of MCP in the Jurkat T cell line. Taken together, these studies suggest a src family-dependent pathway for signaling through MCP.

Amino Acid Sequence↗
PubMed1983

Fusidane antibiotics produced by dermatophytes.

Isolates of Microsporum canis, Microsporum gypseum and Epidermophyton floccosum were observed to produce antibacterial activities under cross-resistance to fusidic acid. The activity from E. floccosum was shown to be due to fusidic acid, diketofusidic acid and 3-ketofusidic acid. Possible contributions of these antibiotics to microbial interaction during dermatophytosis is discussed.

Anti-Bacterial Agents↗
PubMed1999

Rapid appearance of M cells after microbial challenge is restricted at the periphery of the follicle-associated epithelium of Peyer's patch.

M cells within the follicle-associated epithelium (FAE) of the gut play a central role in the initiation of mucosal immune responses by transporting antigens to the intestinal lymphoid tissue. We have previously demonstrated that the instillation into the gut of a nonenteric microorganism, Streptococcus pneumoniae R36a, is an excellent experimental model to investigate the highly dynamic nature of the FAE in response to microbial challenge. In the present study, S. pneumoniae was introduced into rabbit ileal loops, each one containing a Peyer's patch (PP), and the number of M cells was assessed by morphological and functional characteristics in different areas of the FAE after a short time (1-3 hours). We report that a marked increase in the number of M cells was detected in the periphery, but not in the apical area, of the FAE as early as 1 hour after exposure to S. pneumoniae. Furthermore, a variant of this experiment enabled us to establish that the increased numbers of M cells led to an improved capability of the FAE to transport latex fluorescent microspheres (0.5 microm), highly specific to rabbit M cells, from the gut lumen to the intestinal lymphatic system. In these animals the cisterna chyli was cannulated, and the microparticles were introduced into the intestinal loops after stimulation with pneumococci. The microparticles reaching the lymph were then counted by flow cytometer. We interpreted these results as showing that only enterocytes located within the periphery of the FAE are converted to fully operational M cells by certain microbial interaction and the ability of enterocytes to undergo this conversion may depend on their stage of differentiation.

Animals↗
PubMed2003

The possible role of electromagnetic fields in bacterial communication.

This paper presents a general review of the current knowledge regarding bacterial communication via electromagnetic fields. The possible role of ultraviolet, visible and infrared light, extremely high frequency and low frequency electromagnetic fields as well as sound waves is discussed. The probable mechanisms of remote microbial interactions are raised. Future trends in the area of microbiology are also viewed.

Acoustics↗
PubMedDate not supplied

[Infection and inflammation of the urinary tract: various cases of urinary tract infections investigated with the Thomas' test during forced water loading].

We simultaneously employed the Water-Loading Test and the ABU Test in three patients suffering from UTI, when the commonly recommended diagnostic tests did not give explanatory results. Two different bacterial strains were discovered in two cases; in one case the strain responsible of the renal involvement was identified, in the other cases the results induced to perform further invasive procedures not recommended on the basis of the routine laboratory techniques. If the clinical interest of this approach is limited to selected cases, the results obtained induce to discuss about the various problems related to the host-microbial interactions in the pathogenesis of UTI.

Child↗
PubMed1985

Colonization of the oropharynx with pathogenic microorganisms--a potential risk factor for infection in compromised patients.

The indigenous oropharyngeal microflora is complex and consists of many different aerobic and anaerobic microorganisms. Nonindigenous pathogenic microorganisms do not normally colonize the oropharynx due to several different defense mechanisms such as cell specific bacterial attachment, secretion of antibacterial substances and immunoglobulins. Also microbial interactions play an important role in the prevention of new colonization of the oropharynx. Suppression of the indigenous flora by antibiotics promote new colonization. Patients that are severely compromised by disease may be infected by colonizing microorganisms. At special risk are patients with low neutrophil count and patients that are prone to aspiration pneumonia. Thus new colonization should be prevented in such risk patients. Careful monitoring of systemic antimicrobial therapy is essential and decontamination of oropharynx with local antimicrobial agents may be of value.

Attachment Sites, Microbiological↗
PubMed1977

Some observations on biodegradation of pollutants in aquatic systems.

The biodegradability of pollutants introduced into aquatic environments is subject to many variabilities characteristic of microbial processes. Some observations have been reported on studies with p-cresol, methyl parathion, benzo[b]thiophene, dibenzothiophene, 9H-carbazole, quinoline, benzo[f]quinoline, benz[a]anthracene, benzo[a]pyrene, 7H-dibenzo[c,g]carbazole, Mirex, 2,4-dichlorophenoxyacetic acid, Lindane and 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane analogs. Water reservoirs included a eutrophic stream, a eutrophic pond, an oligotrophic lake and effluents from waste-water treatment plants. The first ten of the above compounds were studied only in aerobic mixed-culture systems, and Mirex was studied with mixed cultures under both aerobic and anaerobic conditions. Examples were presented of the significance of cometabolism, diauxic processes, film fermentations and microbial interactions in biodegradation studies. Caution is advised in protocols regarding biodegradability of pollutants in aquatic environments.

Bacteria↗
PubMed1993

[Intestinal flora of inpatients and isolation frequency of methicillin-resistant Staphylococcus aureus].

The authors compared intestinal flora from 30 healthy volunteers and 128 inpatients. E. coli, B. fragilis, and Bifidobacterium were each detected in the stools of healthy subjects at a frequency of more than 90%, while the incidences of such flora were low in the stools of inpatients: A significant difference was observed between the two groups. E. faecium, P. aeruginosa, Methicillin-resistant Staphylococcus aureus (MRSA), C. difficile, and Candida were detected at high frequencies in the stools of inpatients, as compared with healthy subjects. This finding is attributed to the administration of antimicrobial agents. It is also considered that microbial interaction in maintaining the balance among normal intestinal flora had been lost in patients from whom MRSA and/or C. difficile was isolated. The decrease or elimination of bacterial species antagonistic to such resistant strains must be guarded against, because this can lead to weakening of the defence mechanism against intestinal infection.

Enterococcus faecium↗
PubMed1996

The gut in critical illness: evidence from human studies.

Data from a large number of published human studies support the hypothesis that the gastrointestinal tract of the critically ill patient is an important factor in ICU morbidity and mortality. Changes in proximal gut flora in the critically ill patient predict nosocomial infection with the same organism, while gut-directed therapeutic measures clearly reduce rates of nosocomial infection and may have an impact on mortality Modulation of the systemic inflammatory response through gut derived measures has been no more successful than modulation of that response through more conventional systemic forms of mediator-directed therapy. But if the gastrointestinal tract is an important factor in nosocomial ICU-acquired infection, the bigger unanswered question is, to what extent does infection per se alter outcome in critical illness? Current articulations of the gut hypothesis challenge long-held and probably outmoded views of host-microbial interactions. The challenge to replace them is no less compelling and no less treacherous than it was in the era of Metchnikoff, Lane, or their ancient forebears.

Animals↗
PubMed1999

Use of 16S-rRNA Based Techniques to Investigate the Ecological Succession of Microbial Populations in the Immature Lamb Rumen: Tracking of a Specific Strain of Inoculated Ruminococcus and Interactions with Other Microbial Populations in Vivo.

The establishment of microorganisms in the rumen is a critical step if rumen manipulation is to be accomplished by use of microbial inoculants. Microbial populations in the maturing rumen undergo successional changes and, while in a state of flux, provide a possible opportunity for the introduction of specific strains of bacteria. While the rumen of the young lamb was maturing, we measured changes in several microbial populations with 16S-rRNA specific oligonucleotides: Rumincoccus, Fibrobacter, eukaryotes, Gram-positive bacteria, the Bacteroides-Porphromonas-Prevotella group, and anaerobic rumen fungi. In this study we repeatedly dosed 15 lambs with approximately 3.4 x 10(8) to 0.8 x 10(9) Ruminococcus cells dose(-1), twice a week, for 7 wk from 23 d to 63 d of age. Of the five Ruminococcus strains dosed (R. albus SY3 and AR67, and R. flavefaciens Y1, LP9155, and AR72) the most specific primers (based on 16S rDNA) were obtained for strain SY3. There was an increase in the eukaryotic population during dosing, and it was hypothesized that protozoal predation contributed to the disappearance of strain SY3. At the end of dosing PCR amplification showed that SY3 were approximately 10(9) cells ml(-1), but decreased to below the detection limit of the PCR system (8.6 x 10(4) ml(-1)) within 28 d postdosing. These experiments showed that fibrolytic populations increased significantly (P < 0.1) above the controls during the dosing period and were elevated for several days postdosing. This suggests that dosing of highly fibrolytic bacteria makes more of the fiber available to other organisms able to degrade fiber, and in so doing increases the overall fibrolytic activity of the rumen. Examination of the succession of gram-positive bacteria and the Bacteroides-Porphromonas-Prevotella group showed a decline in relative abundance as the lambs matured.

Journal Article↗
PubMed2006

[Approaches for increasing the culturability of microorganisms].

Only a tiny amount of microorganisms on the earth can be cultured so far, which seriously obstructs the investigation into principles of microbial activities and exploiting microbial resources. To improve the culturing methods and to develop novel culturing techniques is therefore very important to increase the culturabilty of microorganisms and to isolate more uncultured microorganisms, which is of crucial importance to research principles of microbial life, to understand the interaction between microbial cells for correctly designing, applying and manipulating environmental microbial processes. This review systematically summarized the causes for microorganisms' unculturability and recent work on the approaches to increase the culturability of microorganisms. To mimic natural environment (physically, chemically and biologically) and to introduce microbial interactions into culture medium as many as possible is suggested to be of key importance to increase culturability of microorganisms.

Biomimetics↗
PubMed1994

Saliva-bacterium interactions in oral microbial ecology.

Saliva is thought to have a significant impact on the colonization of microorganisms in the oral cavity. Salivary components may participate in this process by one of four general mechanisms: binding to microorganisms to facilitate their clearance from the oral cavity, serving as receptors in oral pellicles for microbial adhesion to host surfaces, inhibiting microbial growth or mediating microbial killing, and serving as microbial nutritional substrates. This article reviews information pertinent to the molecular interaction of salivary components with bacteria (primarily the oral streptococci and Actinomyces) and explores the implications of these interactions for oral bacterial colonization and dental plaque formation. Knowledge of the molecular mechanisms controlling bacterial colonization of the oral cavity may suggest methods to prevent not only dental plaque formation but also serious medical infections that may follow microbial colonization of the oral cavity.

Actinomyces↗
PubMed1997

Physico-chemical interactions in initial microbial adhesion and relevance for biofilm formation.

This paper summarizes initial microbial adhesion events in dental plaque formation, including the physico-chemistry of the interaction between micro-organisms and solid substrata, detachment phenomena under the fluctuating shear of the oral cavity, co-adhesion between pairs of microbial strains, and biosurfactant release. A hypothesis is forwarded on how these initial events might influence the final microbial composition and structure of the plaque, although it is simultaneously emphasized that the necessary techniques for verification of the hypothesis have only recently become available, and supporting evidence is still to be collected.

Bacteria↗
PubMed2002

Synergistic interactions in the microbial world.

After several decades of microbiological research has focused on pure cultures, synergistic effects between different types of microorganisms find increasing interest. Interspecies interactions between prokaryotic cells have been studied into depth mainly with respect to syntrophic cooperations involved in methanogenic degradation of electron-rich substrates such as fatty acids, alcohols, and aromatics. Partners involved in these processes have to run their metabolism at minimal energy increments, with only fractions of an ATP unit synthesized per substrate molecule metabolized, and their cooperation is intensified by close proximity of the partner cells. New examples of such syntrophic activities are anaerobic methane oxidation by presumably methanogenic and sulfate-reducing prokaryotes, and microbially mediated pyrite formation. Syntrophic relationships have also been discovered to be involved in the anaerobic metabolization of amino acids and sugars where energetical restrictions do not necessarily force the partner organisms into strict interdependencies. The most highly developed cooperative systems among prokaryotic cells appear to be the structurally organized phototrophic consortia of the Chlorochromatium and Pelochromatium type in which phototrophic and chemotrophic bacteria not only exchange metabolites but also interact at the level of growth coordination and tactic behaviour.

Bacteria↗
PubMed2004

Microbial dynamics and interactions in the spermosphere.

The spermosphere represents a short-lived, rapidly changing, and microbiologically dynamic zone of soil surrounding a germinating seed. It is analogous to the rhizosphere, being established largely by the carbon compounds released into the soil once the seed begins to hydrate. These seed exudations drive the microbial activities that take place in the spermosphere, many of which can have long-lasting impacts on plant growth and development as well as on plant health. In this review, I discuss the nature of the spermosphere habitat and the factors that give rise to its character, with emphasis on the types of microbial activities in the spermosphere that have important implications for disease development and biological disease control. This review, which represents the first comprehensive synthesis of the literature on spermosphere biology, is meant to illustrate the unique nature of the spermosphere and how studies of interactions in this habitat may serve as useful experimental models for testing hypotheses about plant-microbe associations and microbial ecology.

Animals↗
PubMed2001

Interaction peculiarities between microbial cenosis and local immunity of periodontium of humans under extreme conditions.

The investigations were directed at finding out the peculiarities of both periodontal microflora and local immunity under extreme conditions (spaceflight, saturation diving, antiorthostatic hypokinesia). The obtained results revealed different kinds of interactions amongst which saturation diving resulted in the most severe decrease of commensale microflora level, decrease of local immunity and appearance of periodontal pathogens.

Adolescent↗