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At least 55 records · Page 3Linked to original sources

PubMed1976

In situ morphology of nitrifying-like bacteria in aquaculture systems.

The in situ microbiota from several aquaculture facilities with active nitrification was examined by transmission electron microscopy of thin sections for the presence of bacteria that contained intracytoplasmic membranes characteristic of the nitrifying bacteria. Colonies of bacteria with the cellular morphology of a species of Nitrosomonas were found to be present in both the culture water and in the biological filter slime of a freshwater chinook salmon (Oncorhynchus tshawytscha) culture system. bacteria in the water possessed the normal nitrosomonas type of ultrastructure, whereas similar bacteria in the slime had an aberrant morphology due to multiple invaginations of the cell wall and cyto-membranes and a significantly greater number of ribosomes. These nitrosomonas-like bacteria lysed during enrichment in commonly used media. Bacteria with the morphology of species of Nitrosomonas and Nitrosococcus were also observed in colonies in the surface slimes of marine culture systems for striped bass (Morone saxatilis) and quahaug (Mercenaria mercenaria).

Ammonia↗

PubMed1978

Distribution of ice nucleation-active bacteria on plants in nature.

A replica plating method for rapid quantitation of ice nucleation-active (INA) bacteria was developed. Leaf washings of plant samples from California, Colorado, Florida, Louisiana, and Wisconsin were tested for the presence of INA bacteria. Of the 95 plant species sampled, 74 were found to harbor INA bacteria. Only the conifers were, as a group, unlikely to harbor INA bacteria. All of the INA bacteria isolated resembled either Pseudomonas syringae or Erwinia herbicola. Sufficient numbers of INA bacteria were present on the samples to account for the ice nuclei associated with leaves that are necessary for freezing injury to occur. Numbers of INA bacteria were large enough to suggest that plant surfaces may constitute a significant source of atmospheric ice nuclei.

California↗

PubMed1977

Survival of bacteria from human dental plaque under various transport conditions.

The effects of transport media, temperature, and anaerobiosis on the survival of bacteria from human supragingival dental plaque were studied. Individual samples were obtained by passing sterile, unwaxed dental floss through the interproximal spaces. The plaque-bearing portion of floss was immediately placed in vials containing reduced transport fluid, viability-preserving microbistatic medium, or reduced salt solution transport fluid. Plaque samples were dispersed by ultrasonic oscillation, serially diluted, and plated in duplicate on MM10-sucrose-blood agar, mitis salivarius bacitracin agar, and Rogosa tomato juice agar. Initial viable counts (time 0) were compared with viable count determinations after 48- and 72-h storage. Quantitative recovery (>30%) of various groups of oral bacteria was accomplished from both reduced transport fluid and viability-preserving microbistatic medium after 48- and 72-h storage. Storage of dental plaque in reduced salt solution proved unsatisfactory for most bacteria (less than 10% survival). Since growth of some bacteria may occur in viability-preserving microbistatic medium and the charcoal present interferes with colonly enumeration on low-dilution plates, we found reduced transport fluid to be the most suitable medium for transport and recovery of bacteria from supragingival dental plaque. Subzero storage (-196 and -40 degrees C) did not enhance the survival of bacteria from dental plaque; storage at moderate (5 and 20 degrees C) temperatures gave better recovery of viable bacteria. Survival after anaerobic or aerobic storage was comparable for total colony-forming units; however, anaerobic storage enhanced survival of Streptococcus mutans and Lactobacillus. Since these organisms are specifically associated with dental caries, anaerobic techniques are preferred for caries activity testing of plaque.

Aerobiosis↗

PubMed1978

Antibody-coated bacteria in the urinary sediment of rats with experimental pyelonephritis.

The appearance of antibody-coated bacteria in urinary sediment has been evaluated in rats with experimental pyelonephritis. At day 7 after induction of pyelonephritis, 9 out of 11 rats demonstrated antibody-coated bacteria in the urinary sediment. The other 2 rats never had a positive urinary sediment. Following removal of the pyelonephritic kidneys, antibody-coated bacteria disappeared in 7 of 9 previously positive rats. In the 2 rats which continued to show antibody-coated bacteria, the infecting organisms were found in the remaining kidney. The 2 rats which never developed antibody-coated bacteria in urinary sediment had a higher then normal serum antibody titer, and 1 rat with antibody-coated bacteria showed a normal serum antibody titer. It is concluded that although the search for antibody-coated bacteria in urinary sediment is a very useful technique, its negativity does not exclude upper urinary tract involvement; in the case of renal parenchymal infection, immunity is not the same at the systemic and the local site.

Animals↗

PubMed1979

Influence of culture medium of the fatty-acid profile in enteric bacteria.

Enteric bacteria having a high content of cyclopropane fatty acids steeply increase their synthesis when grown on insufficiently propitious culture media (meat-peptone agar or modified Drobot'ko synthetic medium) as compared with bacteria grown under more favourable conditions (meat-peptone broth). Simultaneously, a decrease in monounsaturated fatty acids and increase in palmitic acid are observed. One of the main factors underlying the change in the proportion of fatty acids in bacteria grown on synthetic medium is an increase in medium pH in the process of their growth. Enteric bacteria containing minute amounts/or not containing cyclopropane fatty acids at all (under the experimental conditions used) change their fatty-acid profile little if the culture medium is changed. When grown under insufficiently favourable conditions, these bacteria mainly display an enhanced content of palmitic acid and a lowered content of octadacenoic acid as compared with bacteria grown under more favourable conditions. Of the culture media used, meat-peptone broth, which affords the most favourable conditions for eneteric bacteria growth, is the most suitable medium for obtaining data of taxonomic value.

Culture Media↗

PubMed1979

Attachment of bacteria to soft contact lenses.

A total of 25 soft contact lenses from 17 asymptomatic contact lens wearers and eight patients with contact lens-associated giant papillary conjunctivitis were examined by scanning electron microscopy. Structures that resembled bacteria were present on the anterior surface of seven lenses. All lenses showed a coating of granular mucus-like deposits. Some bacteria were seen scattered randomly over the surface, with no apparent attachment to the lens, whereas others were attached to the coated surface by thin, flagella-like foot processes, the distal ends of which were unattached. These attached bacteria were cylindrical in shape. Several bacteria showed a constriction centrally. Some bacteria were covered by the surface coating, while others, which were round to ovoid in shape, appeared partially embedded in the coating itself. Aggregations of bacteria were seen around clumps of mucus-like debris.

Bacteria↗

PubMed2025

Single-Cell Force Spectroscopy Uncovers Root Zone- and Bacteria-Specific Interactions.

Understanding root-bacteria interactions with plant growth-promoting rhizobacteria (PGPR) is key to developing effective biofertilizers for sustainable agriculture. We performed single-cell force spectroscopy using the atomic force microscope (AFM) to study the primary attachment of two PGPR, Bacillus velezensis and Pseudomonas defensor, to different regions of Arabidopsis thaliana roots. Force measurements with individual cells uncovered distinct attachment strategies by each strain, involving binding via micrometer-long polymers from both bacteria and root surfaces. Flagella differentially affected the binding interactions of each PGPR; their removal altered binding characteristics differently for each strain, highlighting the importance of flagella in early root colonization. Using silica beads to mimic the negatively charged bacteria, we demonstrated the influence of electrostatic forces on root-bacteria interactions. We also examined interactions with abiotic surfaces of varying surface energies, revealing the roles of hydrophilic and hydrophobic forces in initial binding. Our measurements show that differences in the physicochemical properties of bacteria and roots are responsible for variations in primary attachment strategies between PGPR strains and root regions. Parallel fluorescence measurements corroborated our AFM single-cell analysis. Overall, our results provide a nanoscale view of bacterial attachment to roots, offering key insights into how beneficial bacteria colonize roots, crucial for enhancing biofertilizer effectiveness.

Plant Roots↗

PubMed2024

Comparative genomic analysis and functional investigations for MCs catabolism mechanisms and evolutionary dynamics of MCs-degrading bacteria in ecology.

Microcystins (MCs) significantly threaten the ecosystem and public health. Biodegradation has emerged as a promising technology for removing MCs. Many MCs-degrading bacteria have been identified, including an indigenous bacterium Sphingopyxis sp. YF1 that could degrade MC-LR and Adda completely. Herein, we gained insight into the MCs biodegradation mechanisms and evolutionary dynamics of MCs-degrading bacteria, and revealed the toxic risks of the MCs degradation products. The biochemical characteristics and genetic repertoires of strain YF1 were explored. A comparative genomic analysis was performed on strain YF1 and six other MCs-degrading bacteria to investigate their functions. The degradation products were investigated, and the toxicity of the intermediates was analyzed through rigorous theoretical calculation. Strain YF1 might be a novel species that exhibited versatile substrate utilization capabilities. Many common genes and metabolic pathways were identified, shedding light on shared functions and catabolism in the MCs-degrading bacteria. The crucial genes involved in MCs catabolism mechanisms, including mlr and paa gene clusters, were identified successfully. These functional genes might experience horizontal gene transfer events, suggesting the evolutionary dynamics of these MCs-degrading bacteria in ecology. Moreover, the degradation products for MCs and Adda were summarized, and we found most of the intermediates exhibited lower toxicity to different organisms than the parent compound. These findings systematically revealed the MCs catabolism mechanisms and evolutionary dynamics of MCs-degrading bacteria. Consequently, this research contributed to the advancement of green biodegradation technology in aquatic ecology, which might protect human health from MCs.

Humans↗

PubMed1977

Antibody-coated bacteria in the ejaculate: a possible test for prostatitis.

An immunofluorescence technique was used to study antibody coating of bacteria in ejaculates from 14 healthy individuals and 51 patients with complaints compatible with the diagnosis of prostatitis. Quantitative bacteriological cultures in the ejaculate were positive in 2 healthy individuals (14%) and in 25 patients with prostatic symptoms (49%). Antibody-coated bacteria could be demonstrated in 25 patients with prostatic symptoms (49%), 8 of whom had negative bacterial cultures, but in none of the healthy individuals. All 5 patients with epididymitis had antibody-caoted bacteria in the ejaculate. The 13 patients with antibody-coated bacteria in the ejaculate were given antibiotic treatment and the bacteria disappeared in 8 cases. The results document the presence of a (presumably local) immune response in bacterial prostatitis. Antibody coating of bacteria in the ejaculate seems to be helpful in the diagnosis of bacterial prostatitis.

Antibodies↗

PubMed1976

Immunochemical study of the peptidoglycan of gram-negative bacteria.

The specificity of antibodies directed against the peptidoglycan of gram-negative bacteria was studied. The peptidoglycans of Proteus vulgaris, Escherichia coli, Moraxella glucidolytica, Neisseria perflava, give identical precipitin reactions. By means of inhibition studies with various peptidoglycan subunits and synthetic peptides, it was shown that the antibodies are essentially directed against the peptide moiety of the peptidoglycan: L-Ala-D-Glu (L)-mesoA2pm-(L)-D-Ala, that the peptide reacts better with antibodies when it is not cross-linked, and that the C-terminal portion-meso-A2pm-D-Ala of the peptide is immunodominant. These results explain the immunological identity of the peptidoglycans of gram-negative bacteria, which possess the same peptide subunit. Only weak cross-reactivity was observed with the peptidoglycans of gram-positive bacteria (Streptococcus faecium, Micrococcus lysodeikticus, Corynebacterium poinsettiae) where meso-diaminopimelic acid is replaced by L-lysine or L-homoserine. However, the peptidoglycan of Bacillus megaterium which possesses the same peptide subunit as gram-negative bacteria, gives only a reaction of partial identity with these bacteria. This result suggests the presence on the peptidoglycan of gram-negative bacteria, of other undefined antigenic determinants.

Bacteria↗

PubMed1978

Phototrophic purple and green bacteria in a sewage treatment plant.

In all purification stages of a biological sewage treatment plant, phototrophic bacteria were detected by the method of viable cell counts. The predominant species identified belonged to the genus Rhodopseudomonas of purple nonsulfur bacteria. The number of phototrophic bacteria was highest in wastewater containing sludge. In activated sludge, an average of 10(5) viable cells/ml was found; the number depended upon concentration of sludge rather than on seasonal changes in light conditions in the course of a year. Bacteriochlorophyll a was extracted from activated sludge. Relative to the viable counts of phototrophic bacteria, the content of bacteriochlorophyll a was 5- to 10-fold higher than that of three representative pure cultures. By incubation of activated and digester sludge under different environmental conditions, it was shown that phototrophic bacteria can complete with other bacteria only under anaerobic conditions in the light.

Aerobiosis↗

PubMed1979

Comparison of antibodies in marine fish from clean and polluted waters of the New York Bight: relative levels against 36 bacteria.

Fish from polluted waters are subject to increased prevalence of disease. Because they respond to bacterial pathogens by producing serum antibodies, it was possible to construct a seasonal serological record in three fish species from clean and polluted waters of the New York Bight. Antibody levels were determined by testing sera for agglutinating activity against 36 strains of bacteria. Evaluation of 5,100 antibody titrations showed the following. During warm months, summer flounder (Paralichthys dentatus) from the polluted area had significantly higher antibody levels and antibody to a greater diversity of bacteria than fish from the unpolluted area. Weakfish (Cynoscion regalis) from the same polluted area shared with summer flounder raised titers to many bacteria. The greatest proportion of raised titers was against Vibrio species, although prominent titers were also seen against Aeromonas salmonicida and Haemophilus piscium, bacteria usually associated with diseases in freshwater but not marine fish. Differences between polluted and clean waters were not as evident in winter flounder (Pseudopleuronectes americanus) during cold months. This could be due, in part, to reduced antibody production at colder temperatures. The data illustrate the usefulness of the serum antibody record in identifying environmental exposure to bacteria in marine fish and indicate that the polluted New York Bight apex has increased levels and diversity of bacteria during warm months.

Animals↗

PubMed1978

Effects of storage in an anaerobic transport system on bacteria in known polymicrobial mixtures and in clinical specimens.

An anaerobic transport system (ATS) which provides for catalytic removal of oxygen was evaluated by using in vitro-prepared polymicrobial mixtures of logphase bacteria and clinical specimens. Inoculated swabs were stored at room temperature in (i) aerobic, (ii) anaerobic glove box, and (iii) ATS environments, and bacteria were quantitated after 2, 24, 48, and 72 h. Bacteria in a three-part mixture of Bacteroides fragilis, Peptostreptococcus anaerobius, and Escherichia coli and in a five-part mixture of B. fragilis, P. anaerobius, Fusobacterium nucleatum, Staphylococcus epidermidis, and Pseudomonas aeruginosa survived 72 h of storage in the ATS and anaerobic glove box environments, but the anaerobic species were inactivated in the aerobic storage except for B. fragilis in pure culture or in the three-part mixture. Changes in relative proportions among the species in a mixture were least in the ATS and anaerobic glove box environments and greatest during the aerobic storage, particularly in the five-part mixture. Bacteria present in pure or mixed culture in clinical specimens generally survived 72 h of storage in the ATS. These data indicate that changes in relative proportions occur with prolonged storage even under anaerobic conditions, but that the ATS would be most effective for preserving anaerobic bacteria and preventing drastic concentration changes and overgrowth of facultative and aerobic bacteria.

Anaerobiosis↗

PubMed1976

In situ morphologies of deep-sea and sediment bacteria.

Deep-sea and sediment bacteria at the bottom of an approximately 1200-m water column were sampled by means of pressure vessels attached to a remote underwater manipulator. Cells were immediately fixed in situ with glutaraldehyde, and after processing in the laboratory their morphologies were observed with the scanning electron microscope. Most bacteria were coccoid or rod-lide and less than 0.4 mum in diameter or width. Few filamentous bacteria were observed. Bacteria were in aggregates or free-living. It is concluded that morphologies of deep-sea bacteria collected and fixed at the hydrostatic pressure of their environment are, in general, similar to the observed morphologies of deep-sea bacteria determined at 1 atm pressure after collection and decompression during ascent through the water column.

Bacteria↗

PubMed1979

Nitroblue tetrazolium (NBT) reduction by bacteria. Some properties of the reaction and its possible use.

All the S. albus, E. coli and P. aeruginosa strains examined reduced nitroblue tetrazolium (NBT) to dark blue formazan. The amount of formazan produced was proportional to the number of bacteria. Under the same growth conditions, an equal number of bacteria of various strains produced different amounts of formazan. However, there were statistically verified differences in the NBT-reduction between the three species examined. The NBT-reduction took place in all phases of growth but was most intense in the early logarithmic phase. NBT was found to be toxic for bacteria, and the different strains had varying sensitivity to that effect. The NBT-reaction was markedly enhanced by phenazine methosulphate (PMS). The blue colour of formazan produced from NBT has an advantage over the red colour from triphenyltetrazolium chloride (TTC) if the reaction occurs in the presence of haemoglobin often present in biological materials. With NBT and PMS, 10(6)--10(7) bacteria are needed to form detectable amounts of formazan. The NBT-reduction by bacteria may be useful for measuring the influence of bactericidal, bacteriostatic or growth-stimulating factors on bacteria.

Bacteria↗

PubMedDate not supplied

Dynamics of production of extracellular polysaccharides by nodule bacteria.

The dynamics of the accumulation of the extracellular polysaccharides synthesized by nodule bacteria and the possibility of their assimilation by these bacteria as a source of carbon was studied. When nodule bacteria were cultured for 20 days in a medium containing glucose, an increase in the titer of the bacteria and the accumulation of extracellular polysaccharides was observed in the first three days. After this the titer of the nodule bacteria decreased with a decrease in the glucose in the medium, but the amount of extracellular polysaccharide synthesized did not increase. These data suggest that extracellular polysaccharides are not assimilated by nodule bacteria as a source of carbon and evidently are protective substances for the cells.

Bacteria↗

PubMed1979

Diagnosis of Salmonella bacteria: antibodies against synthetic Salmonella O-antigen 8 for immunofluorescence and co-agglutination using sensitized protein A-containing staphylococci.

An antiserum against the synthetic disaccharide abequose 1 leads to 3 alpha rhamnose (AR), representative of Salmonella O-antigen 8, coupled to bovine serum albumin (BSA) was used for diagnosis of Salmonella bacteria by indirect immunofluorescence (IFL) and by co-agglutination (COA) using sensitized protein A-containing staphylococci. Among the 1150 enteric bacteria tested in IFL, the antiserum correctly identified all 99 Salmonella serogroup C2 and C3 bacteria with O-antigen 8. No fluorescence was seen with 484 Salmonella bacteria belonging to other serogroups or 567 non-Salmonella enteric bacteria. The anti-AR-BSA serum was favourable as compared to a conventional Salmonella factor O8 serum as regards both titre and specificity. In the COA test, all 22 Salmonella serogroup C2 and C3 strains agglutinated strongly and within seconds, whereas no agglutination could be seen when 93 Salmonella bacteria representing other serogroups were tested.

Agglutination Tests↗

PubMed1976

Selective adherence as a determinant of the host tropisms of certain indigenous and pathogenic bacteria.

The relationship between the selective abilities of bacteria to adhere and their predilections for colonizing different mammalian hosts was investigated by using bacteria indigenous to the tongue dorsum of humans and rats as models. Streptococcus salivarius and S. sanguis averaged 22.6 and 2.8%, respectively, of the cultivable bacteria recovered from swab samples of the tonges of five humans, but these organisms were not indigenous on the tongues of rats (Charles River strain). S. faecalis and serum-requiring diphtheroids were consistently prominant on the tongues of rats, but they were not detected on the tongues of the humans examined. The ability of these organisms to adhere to the tongue surface of the hosts was compared by introducing mixtures of streptomycin-resistant strains into the mouths of human volunteers and rats. S. salivarius adhered in higher proportions to the dorsal tongue surface of humans than did strains of S. faecalis and the serum-requiring diphtheroid. S. sanguis also adhered to human tongues better than the serum-requiring diphtheroid. However, S. faecalis and the serum-requiring diphtheroid sorbed in higher proportions to the tongues of rats. In an in vivo assay, human strains of S. pyogenes and S. salivarius attached in higher numbers to buccal epithelial cells derived from humans than to those obtained from rats, whereas the reverse was observed with a serum-requiring diphtheroid derived from rats. Collectively, these studies show that bacteria sorb with a high degree of specificity to the tissues of different mammalian hosts, and the relative adherence of the organisms studied correlated with their natural host tropisms. The selective adherence of S. salvarius and S. faecalis was similar to the tongues of conventional and germ-free rats, suggesting that the presence of an indigenous bacterial flora did not significantly influence their attachment selectivity. Moreover, the ability of these organisms to colonize the tongues of gnotobiotic rats lacking an indigenous flora paralleled their adherence selectivity. Direct scanning microscopic observations indicated that the tongue dorsum of conventional rats is highly papillated but contains relatively sparse bacterial populations. Indigenous organisms colonized the bases of papillae on the anterior tip and lateral edges of the tongue as discrete microcolonies, but bacteria were rarely observed on other papillae. This localized and restricted pattern of colonization and the spatial distribution of the microcolonies of indigenous bacteria present also suggest that antagonistic interactions are unlikely to account for the bacterial tropisms observed for colonization of the tongues of rats.

Animals↗