Great Variety Of Bacteria Research Articles

Influence of the photoperiod duration on the biological properties of PGPR-bacteria of the soybean rhizosphere (Glycine max (L.) Merr.)

Physiological and biochemical properties of the PGPR-bacteria isolated from the rhizosphere of the soybean (Glycine max (L.) Merr), grown under different photoperiod duration were investigated. A short-day soybean cultivar Clark was selected for the study; it was exposed to a long natural day (16 hours – control) and a short day (9 hours – test). The short day was created by darkening the plants with light-tight chambers for three weeks from 5 p.m. to 9 a.m. the next day. The field experiment was carried out at the experimental site of the Department of Physiology and Biochemistry of Plants and Microorganisms of V.N. Karazin Kharkiv National University, located in the Botanical garden of the University. Soil samples from the soybean rhizosphere were taken at the budding phase; the bacteria were isolated in a nitrogen-depleted medium. We studied cultural characteristics of bacteria (Gram stain, bacterial morphology, mobility, type of respiration, oxidase and catalase positivity) and their physiological and biochemical properties (the capability of proteolysis and nitrate reduction). A greater variety of bacteria in terms of cultural properties was isolated from the rhizosphere of soybean grown under long-day conditions. Probably, this is due to the higher intensity of root exudate excretion (chemoattagative factors) during the long day which is caused by different metabolic intensities at various photoperiod lengths. The highest number of isolates with proteolytic activity was observed in bacteria under long-day conditions. This property is considered to have a significant impact on the mineral nutrition of plants. Analysis of literature data showed that the higher amount of protein is accumulated in soybean leaves during the long day as a result of intensification of nitrogen nutrition provided by bacteria capable of proteolysis. Under conditions of a short day, a higher number of isolates capable of nitrate reduction was observed. A decrease in the number of isolates capable of nitrate reduction under a long-day condition can be explained by the possible repression of assimilative nitrate reductase by a large amount of ammonium formed during the ammonification of organic substances. Thus, the obtained results suggest that the photoperiod duration can determine physiological and biochemical properties of the rhizosphere microbiota of the plants sensitive to this factor.

Abstract LB223: Beans to Enrich the Gut microbiome vs. Obesity's Negative Effects: First results from the BE GONE Trial in high-risk colorectal patients

Abstract Background: Dry beans are a prebiotic food source rich in bioactive compounds with anti-inflammatory, anti-lipidemic and chemopreventive properties. The BE GONE trial tested the impact of an increase in dry bean consumption on gut microbiota and blood lipid profiles in high-risk colorectal (CR) patients otherwise consuming their usual diet. Methods: Following initiation of the pilot protocol (July 2016) among patients with a high-risk BMI and/or waist circumference and history of precancerous CR polyps, the crossover trial was expanded to patients with a history of CR cancer (May 2017). Patients were block randomized according to no vs. regular use of chronic disease medications commonly prescribed in the target population. Following a 4-week run-in/equilibration period, participants were randomized to continue the control diet (usual diet, no dry beans) or to begin the intervention diet (usual diet + dry beans). The intervention included a 2-week ramp-up to 1 cup/day navy beans (12 g dietary fiber; 14 g protein; 200 kcal) continued for an additional 6 weeks. Dietary habits, body weight, and other lifestyle parameters were monitored throughout the 20-week study. We characterized the 16Sv4 rDNA microbiome (Illumina MiSeq) and CLIA cholesterol panel in serial stool and fasting blood samples collected at baseline, week 4, and week 8 for each crossover period (n=249). Longitudinal analyses were conducted using generalized linear mixed models with random intercept and slope adjusted for chronic disease medication use examining the post-intervention effect from baseline to 4 weeks and baseline to 8 weeks. Results: Eligible patients were enrolled in the 4-week run-in/equilibration (n=69). Of these, 55 were randomized and 50 completed the 20-week trial in December 2019 with >80% compliance. Primary reasons for withdrawal were work/travel/family obligations. Half (54%) of the participants were male, 74% were CR cancer survivors, 76% were white (non-Hispanic) and 40% were on statins and/or metformin. Pre-study dietary profiles were characterized by low mean intake of legumes (<3 servings/month) and dietary fiber (17 g/day). The 8-week increase in bean intake significantly increased the inverse Simpson index [effect estimate and 95% CI: 1.59 (0.10, 3.08)], a diversity measure reflecting a greater variety of bacteria with a more even relative abundance. Longitudinal analyses restricted to taxa present in >80% of patients at baseline, revealed significantly decreased Anaerostipes and Streptococcus at week 4 and increased Faecalibacterium at week 8, along with temporal fluctuations in other known specialized (e.g., pectin) and versatile fiber-fermenting bacteria of the Lachnospiraceae and Ruminococcaceae families. A modest decrease in LDL cholesterol was observed at 8-weeks [-2.64 (-6.91, 1.62)] Conclusions: Early results of the BE GONE trial suggest that an 8-week increase in dry bean intake may be sufficient to balance or enrich the gut microbiome of high-risk CR patients. Continued sample processing and analysis, including stool metagenomics and blood metabolomics should continue to shed light on functional interactions relevant to the human host. Citation Format: Xiaotao Zhang, Kristi L. Hoffman, Fangyu Li, Ehsan Irajizad, Gladys Browman, Karen Basen-Engquist, Samir Hanash, Paul Scheet, Pablo C. Okhuysen, Scott Kopetz, Joseph Petrosino, Carrie R. Daniel. Beans to Enrich the Gut microbiome vs. Obesity's Negative Effects: First results from the BE GONE Trial in high-risk colorectal patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB223.

The Prevalence of Oral Flora in the Biofilm Microbiota of the Endotracheal Tube

The endotracheal tube (ETT) is recognized as an independent factor for infection in intubated patients. The presence of biofilm contributes to the development of pneumonia. Standard culturing techniques are inadequate to detect many of the bacteria present in a biofilm. Delineation of the microbiota in the ETT is needed to further understand infections in ventilated patients. A prospective, observational study was performed at a university, Level I trauma center. Twenty ETT were collected at extubation. Bioluminal accretions were removed and quantified. DNA was extracted and 16S ribosomal RNA gene analysis performed using the Human Oral Microbe Identification Microarray. Twenty ETT were evaluated. Mean age was 47.5 years (19-82). Five were smokers. Mean ventilator days was 3.6 ± 3.1. Mean intensive care unit days was 7.8 ± 6.3. In those ETT, 87 different bacterial species were identified. Mean number of bacterial species identified was 16 ± 9 (3-35). There was no relationship between duration of intubation and number of species (P = 0.5). Nonsmokers had a greater variety of bacteria than smokers (P = 0.03). Patients with pneumonia did not have a greater variety of bacteria (P = 0.14). Parvimonas micra presence was associated with reintubation (P = 0.01). The most common species in smokers were different from nonsmokers. There is a wide variety of bacteria present in an ETT, many of which cannot be cultured by standard means. Variation is not correlated to duration of intubation or accretion volume. Studies to evaluate these bacteria and their interaction with the biofilm may further delineate factors in development of infections.

Microbiology and foodborne pathogens in honey

ABSTRACTHoney has been considered a relatively safe foodstuff due to its compositional properties, with infant botulism caused by Clostridium botulinum being the most prominent health risk associated with it. Our review is focused on the honey microflora along the food chain and evaluates the pathogenic potential of those microorganisms found in honey. This product may contain a great variety of bacteria and, particularly, fungi that eventually entered the food chain at an early stage (e.g., via pollen). For many of these microorganisms, opportunistic infections in humans have been recorded (e.g., infections by Staphylococcus spp., Citrobacter spp., Escherichia coli, Hafnia alvei, Aspergillus spp., Fusarium spp., Trichoderma spp., Chaetomium spp.), although direct infections via honey were not registered.

Effect of organic carbon on ammonia oxidizing bacteria in a mixed culture

This study examined the effect of organic carbon (peptone vs. glucose) on two sequencing batch reactors performing simultaneous carbon oxidation and nitrification. Although each reactor had similar COD oxidation kinetics (0.029 and 0.036 mg COD mg VSS −1 h −1), the Monod nitrification kinetics for the peptone-fed reactor ( μ m = 2.72 h −1, K s = 17.8 mg N L −1) were faster than for the glucose-fed reactor ( μ m = 0.868 h −1, K s = 26.5 mg L −1). The overall bacterial communities were profiled by 16S rRNA cloning and sequencing and revealed homology with a greater variety of bacteria from the peptone-fed reactor than the glucose-fed reactor. In addition, amoA cloning and sequencing, terminal restriction fragment length polymorphism, and fluorescent in situ hybridization experiments indicated greater AOB diversity and abundance in the peptone-fed reactor. This research provides evidence that the organic carbon source affects the make-up of the heterotroph community as well as AOB in mixed cultures.

New strategies for combination vaccines based on the extended recombinant bacterial ghost system

Controlled expression of cloned PhiX174 gene E in Gram-negative bacteria results in lysis of the bacteria by formation of an E-specific transmembrane tunnel structure built through the cell envelope complex. Bacterial ghosts have been produced from a great variety of bacteria and are used as non-living candidate vaccines. In the recombinant ghost system, foreign proteins are attached on the inside of the inner membrane as fusions with specific anchor sequences. Ghosts have a sealed periplasmic space and the export of proteins into this space vastly extents the capacity of ghosts or recombinant ghosts to function as carriers of foreign antigens, immunomodulators or other substances. In addition, S-layer proteins forming shell-like self assembly structures can be expressed in bacterial candidate vaccine strains prior to E-mediated lysis. Such recombinant S-layer proteins carrying inserts of foreign epitopes of up to 600 amino acids within the flexible surface loop areas of the S-layer further extend the possibilities of ghosts as carriers of foreign epitopes. As ghosts do not need the addition of adjuvants to induce immunity in experimental animals they can also be used as carriers or targeting vehicles or as adjuvants in combination with subunit vaccines. Matrixes like dextran which can be used to fill the internal lumen of ghosts can be substituted with various ligands to bind the subunit or other materials of interest. Oral, aerogenic or parenteral immunization of experimental animals with recombinant ghosts induced specific humoral and cellular immune responses against bacterial and target components including protective mucosal immunity. The most relevant advantage of ghosts and recombinant bacterial ghosts as immunogens is that no inactivation procedures that denature relevant immunogenic determinants are employed in the production of ghosts. This fact explains the superior quality of ghosts when compared to other inactivated vaccines. As carriers of foreign antigens there is no limitation in the size of foreign antigens to be inserted and the capacity of all spaces including the membranes, periplasma and internal lumen of the ghosts can be fully utilized. Using the different building blocks and combining them into the recombinant ghost system represents a new strategy for adjuvant free combination vaccines.

Enrichment for estuarine petroleum-degrading bacteria using liquid and solid media.

Bacteria in oil‐contaminated and oil‐free estuarine water and sediment were isolated on solid and in liquid petroleum media. A greater variety of bacteria was noted when direct plating techniques were employed, compared with liquid enrichment. In addition, strains isolated by liquid enrichment were found more frequently to be capable of utilizing model petroleum in vitro, compared with isolates obtained by direct plating.

A STUDY OF THE LESIONS PRODUCED BY FILTRATES OF INFLUENZA SPUTUM

The hypothesis of a filtrable virus as the primary etiologic agent in epidemic influenza has been advanced by Nicolle and LeBailly,1von Angerer,2Bradford, Bashford and Wilson,3and by Gibson, Bowman and Connor.4The great diversity of bacteriologic findings in the disease would seem to render such a conception very attractive. It would appear very difficult to explain the epidemiologic characters of the disease on the assumption that it is primarily caused by any of the well known bacteria which have from time to time been associated with it, but which are also known to be present and active in the inter-epidemic periods. The clinical conception of influenza as a comparatively mild disease, characterized by a well marked toxemia and giving evidence of special predilection for the respiratory tract, and only dangerous, as a rule, when complicated by the so-called secondary pneumonia, from which a great variety of bacteria have

Inhibitory Action of Lactic Acid on Certain Bacteria and Fungi

In his instructions for the cultivation of fungi and especially the isolation of pure strains, Duggar1 recommends the use of lactic acid in the culture mediums. He claims that, in general, 0.5% of lactic acid is sufficient to prevent the growth of contaminating bacteria. As there is little or no available information concerning the inhibitory effects of lactic acid on any great variety of bacteria, although there is as to a few special forms, this work was undertaken with a view of determining the effect on common bacteria and certain fungi. Apart from its bearing on methods of cultivation, there is possibly a more important relation between bacteria and lactic acid. Under pathologic conditions lactic acid is the most widely distributed and abundant acid in the body. It is found in the tissues, in the secretions of the stomach, in abscesses, and in various fluids of the body. It is asserted by Fischer that an increased production of acids in the tissues is responsible, to a large degree, for the occurrence of edema. Therefore, since lactic acid is so commonly found in the body, it would seem that the action of this acid on bacteria might be a truer test of the tolerance of bacteria toward acid, that is toward the effect of the hydrogen-ion, than would be that of an inorganic acid like hydrochloric, as we are more nearly approximating common pathologic conditions found in the body. The method employed in these preliminary experiments was as follows :

EXPERIMENTAL STUDY OF BACTERIA ISOLATED FROM TONSILS

Work on the bacteriology of the tonsils has largely been confined to the examination of swabs and smears made directly from the surface of the tonsils in situ . This surface is necessarily contaminated by bacteria from the mouth, throat, nose, food, etc., and the great variety of bacteria reported to have been found here is thus at least partly explained. It is evident, too, that the bacterial flora on the surface may be very different from that in the crypts. The present study, therefore, was made before and after excision of the tonsils and a comparison made of the bacterial flora of the surfaces and in the depths. The tonsils, usually enlarged, were obtained from patients with a variety of clinical conditions, including chronic joint affections, nephritis, endocarditis, rheumatic fever, recurring tonsillitis, etc. The detailed facts are reserved for later publication. Tonsils from forty-five patients have been examined. The excised