Bile salts promote ToxR regulon activation during growth under virulence inducing conditions.

Cholera is an epidemic disease caused by the Gram-negative bacterium Vibrio cholerae . V. cholerae is found in aquatic ecosystems and infects people through the consumption of V. cholerae contaminated food or water. Following ingestion, V. cholerae responds to host cues to activate the expression of critical virulence genes that are under control of a hierarchical regulatory system called the ToxR regulon. The ToxR regulon is tightly regulated and is only expressed in vitro under special growth conditions referred to as AKI conditions. AKI conditions have been instrumental in elucidating V. cholerae virulence regulation, but the chemical cues within AKI medium that activate virulence gene expression are unknown. In this study, we fractionated AKI medium on a reverse phase chromatography column (RPCC) and showed that the virulence activating molecules were retained on the RPCC column, and recovered in the eluate. LC-HRMS analysis of the eluate revealed the presence of a known ToxR regulon activator, taurocholate, and other bile salts. The RPCC eluate activated the ToxR regulon when added to non-inducing media and promoted TcpP dimerization in a two-hybrid system, consistent with taurocholate being responsible for the virulence-inducing activity of AKI medium. Additional experiments using purified bile salts showed that ToxR regulon was preferentially activated in response to primary bile acids. The results of this study shed light on the chemical cues involved in V. cholerae virulence activation and suggested that V. cholerae virulence genes are modulated in response to regional-specific bile acid species in the intestine.

Atomic and Molecular Beams Control in Molecular Beam Epitaxy

Rapid development of molecular beam epitaxy (MBE) in recent decades has led to the emergence of a variety of technological installations, as well as electronic and optical diagnostics of growing layers, as well as atomic and molecular beams. Known methods for monitoring atomic and molecular beams in MBE installations-mass spectrometric and luminescent - involve bulky sensors, which can only be placed in special growth chambers. This paper describes a structurally simple and fairly universal method for determining the intensities of atomic and molecular beams, based on registering the amount of electron scattering at small angles that occur when a narrow electron beam interacts with the atoms of a vaporized substance. We consider the theoretical prerequisites for the diagnosis of an atomic beam by the phenomenon of scattering of fast electrons in it.

Life stages and morphological variations of Limnocythere inopinata (Crustacea, Ostracoda) from Lake Jiang-Co (northern Tibet): a bioculture experiment

Limnocythere inopinata (Baird, 1843) is a Holarctic species, abundant in a number of Recent and fossil ostracod assemblages, and has many important taxonomic and (paleo)ecological applications. However, the life cycle and morphological characteristics of the living L. inopinata are still unclear. A bioculture experiment was designed to study life stages and morphological variations from stage A-8 to adult in this species. The living animals were collected from Lake Jiang-Co, in the northern Tibetan Plateau. Results reveal that this species possesses a special growth pattern with the maximum size increase occurring at the transition from the instars A-5 to A-4. The growth pattern deviates from Brooks’ rule and one population from Lake Dali, eastern Mongolian Plateau. This suggests that the life history of L. inopinata may be influenced by environmental factors. Some morphological differences between Lake Jiang-Co and European populations of L. inopinata are also uncovered. Therefore, a detailed morphological description of this population is provided, but refrain from erecting a new species at the present stage because those differences appear to be inconsistent.

Assessment of Biological Toxicity and Ecological Safety for Urban Black-Odor River Remediation

The judgment and assessment of remediation effect on urban black-odor river still depend on the physical-chemical parameters and lack in ecological safety effects. A set of combined biological toxicity tests were applied to evaluate the ecological effects of one urban black-odor river before and after the remediation. The special growth rate of Chlorella vulgaris and mortality rate of Daphnia magna were used to assess acute toxicity. The Salmonella Typhimurium/Reverse Mutation Assay was applied to test the mutagenicity. The tests by C. vulgaris growth showed that there was no inhibition before and after remediation by overlying water, in contrast promoted the growth of C. vulgaris. The tests by D. magna showed slight toxicity on site 3# before remediation and nontoxic after remediation. The mutagenicity of organic extracts from overlying water at all sampling sites were positive before remediation, but were eliminated after remediation except from 3 of 4 sites on TA98 strain. The addition of the liver microsomal S9 induced the positive mutagenicity on site 4# compared to S9 absence. The results clarified the applicable and the importance of the biological toxicity tests on assessing the remediation effect and potential ecological risk of urban black-odor river.

Experimental Investigation on Bacterial Concrete Using Bacillus Subtitles

This Project deals with the present investigation is to obtain the performance of the concrete by the microbiologically induced special growth. One such has led to the development of a very special concrete known as bacterial concrete or otherwise called as self-healing concrete where the bacteria is induced in the mortars and concrete to heal up the faults. Researchers with different bacteria proposed different concrete. Here an attempt was made by using the bacteria “Bacillus Subtitles”. The Study showed a significant increase in the compressive strength due to the addition of bacteria. When 30ml of Bacillus subtitles is added in M20 grade concrete is attains maximum compressive strength. In Concrete self-healing property is successfully achieved due to addition of bacteria. Bacillus subtitles is used to induce Caco 3 precipitation. The main part of work will focus on how the right conditions can be created for the bacteria not only to concrete but to produce as much calcite as needed to repair cracks.

Isolation and identification of the Myxobacterium Myxococcus fulvus from the Farms and study the inhibitory effect of cells and filtrates against pathogenic fungi

The study was performed to isolate and identify the Myxococcus fulvus from the one hundred samples of soils of farms. Special growth conditions had been used to support the growth of M.fulvus local isolates and suppressed the growth of other microorganisms like (Drying , High Temperature , High concentration of antibiotics and specific growth media ) M.fulvus isolates had been subjected to the morphological, cultural , biochemical examination for identification , as well as , study the inhibitory activites of cells and filtrates of localized isolates against some pathogenic fungi include (Trichophyton mentagrophytes , Microsporum gypseum , Aspergillus niger and Fusarium oxyporum ) by using three methods :- Cup assay , well diffusion and mixed culture , Results obtaind could be summarized as follows :- 1. (20) out of (100) soil samples , M.fulvus isolated as fruiting bodies depending on baiting technique by bacterial bait. 2. The media casiton – yeast extract agar was suitable for obtaind the best growth of vegetative swarms as pure culture . 3. (8) local isolates were showed inhibitory effect against all of the tested pathogenic fungi . 4. The concentrated filtrates of (3) local isolates were showed highly inhibitory effect than their unconcentrated filtrates against all of the tested pathogenic fungi .

Study on Bacillus Isolated from Intestine of Persian Sturgeon (Acipenser persicus) Comparing with Commercial Probiotics

At present, probiotic bacteria are proposed as an important alternative for antibiotic elimination and for providing renewable products through biological control in cultivation systems of marine fish larvae. The aim of this study is to compare the effects of native and commercial probiotics on growth parameters of Persian sturgeon (Acipenser persicus) larvae fed with controlled biomar diet. Experimental diets with three probiotic bacterial mixture including commercial lactobacillus (L. plantarum and L. rhamnosus), commercial Bacillus (B. subtillis and B. licheniformis) and Bacillus isolated from intestine of Persian sturgeon (B. mycoides) were completed in two levels (6.1 and 7.2 log CFU in each g of feed) and were fed to larvae of Persian sturgeon in six experimental treatments. The control treatment was fed with diet without supplementation. The experiment was done in randomized design. In all the treatments, feed conversion index was increased considerably and had significant difference with control treatment and in all the experimental treatments influenced by probiotics were higher than that of control treatment (P<0.05). The highest rate means of special growth (1.84±0.21%) and thermal growth index (3.44±0.37%) was obtained respectively in treatment C1 and C2 (isolated from intestine). Maximum special growth rate (SGR %) were obtained from C1 (4.69±0.71%) and B2 (4.62±0.87%, commercial Bacillus). In addition, native probiotic bacteria had better performance than the non native commercial species as well as selection of suitable probiotic (natural) with respect to fish species, region and condition of culture plays a special importance role in enhancing the yield of Persian sturgeon larvae.