Bacteria Bacillus Subtilis Research Articles

Separation and detection of apricot leaf triterpenes by high-performance thin-layer chromatography combined with direct bioautography and mass spectrometry

Prunus armeniaca leaf extract was screened for antibacterial compounds by high-performance thin-layer chromatography (HPTLC)-direct bioautography using a Gram-positive Bacillus subtilis bacterium. Six chromatographic zones exhibited characteristic bioactivity. Five of them also appeared after derivatization with vanillin-sulfuric acid reagent and could be characterized with HPTLC-electrospray ionization (ESI)-mass spectrometry (MS), suggesting the presence of triterpenoids and the fatty acids linolenic and palmitic acid. To confirm the identification of triterpenoids an HPTLC method using in situ pre-chromatographic derivatization with iodine was developed to separate the closely related triterpenoids. After development, the iodine could be eliminated from the chromatogram (verified by HPTLC-MS), making it suitable for the B. subtilis assay. Ursolic acid, oleanolic acid, betulinic acid, corosolic acid, and maslinic acid were discovered for the first time as antibacterial components of P. armeniaca leaves. Their presence was proved also by 2D-HPTLC combined with intermediate in situ derivatization by iodine.

Functional characterization of the first lipoyl-relay pathway from a parasitic protozoan.

Lipoic acid (LA) is a sulfur-containing cofactor covalently attached to key enzymes of central metabolism in prokaryotes and eukaryotes. LA can be acquired by scavenging, mediated by a lipoate ligase, or de novo synthesized by a pathway requiring an octanoyltransferase and a lipoate synthase. A more complex pathway, referred to as "lipoyl-relay", requires two additional proteins, GcvH, the glycine cleavage system H subunit, and an amidotransferase. This route was described so far in Bacillus subtilis and related Gram-positive bacteria, Saccharomyces cerevisiae, Homo sapiens, and Caenorhabditis elegans. Using collections of S. cerevisiae and B. subtilis mutants, defective in LA metabolism, we gathered evidence that allows us to propose for the first time that lipoyl-relay pathways are also present in parasitic protozoa. By a reverse genetic approach, we assigned octanoyltransferase and amidotransferase activity to the products of Tb927.11.9390 (TblipT) and Tb927.8.630 (TblipL) genes of Trypanosoma brucei, respectively. The B. subtilis model allowed us to identify the parasite amidotransferase as the target of lipoate analogs like 8-bromo-octanoic acid, explaining the complete loss of protein lipoylation and growth impairment caused by this compound in T. cruzi. This model could be instrumental for the screening of selective and more efficient chemotherapies against trypanosomiases.

How Do Bacteria Recognize Their Environment? The Role of a Histidine Kinase in Initiating a Biofilm Program

Many bacteria form complex multicellular communities known as biofilms. While biofilms are a common cause of human infections, they can also have productive roles in ecology and agricultural settings. In contrast to the importance of these communities, less is known about how bacteria interpret and respond to environmental cues to form a biofilm. To help understand how bacteria recognize chemical signals from their environment, we studied the soil‐dwelling bacteria Bacillus subtilis, which is known to form beneficial biofilms on plant roots. We find extracts from many plant samples can stimulate B. subtilis biofilm formation. One protein that is likely important for the recognition of plant signals is a histidine kinase called KinD. KinD is known to have a role in biofilm formation and also to bind the molecule pyruvate. We find there are varying pyruvate concentrations in our different biofilm‐stimulating plant samples. Using transcriptional reporters of biofilm genes, we show that the binding of pyruvate to KinD can initiate the primary biofilm pathway of B. subtilis. However, the addition of pyruvate to bacterial cultures is not sufficient to trigger a biofilm phenotype. This research suggests that the binding of pyruvate to KinD is one of several signals that initiate the formation of a robust biofilm.

Potential bioactive secondary metabolites of Actinomycetes sp. isolated from rocky soils of the heritage village Rijal Alma, Saudi Arabia

The present study was designed to discover novel secondary antibiotic metabolites from Actinomycetes species from the soil of Rijal Almaa, Saudi Arabia. A laboratory-scale benchtop fermentation was utilized for the demonstration of antibiotics from the soil actinomycetes. Fourier transform-infrared spectroscopy (FT-IR) spectroscopy analysis of the fermented product (FP) was carried out, which showed unique fingerprint regions indicating the presence of phenolic hydroxyl groups, aliphatic compounds, carboxylic groups, esters, isothiocyanate, etc. GC-MS analysis of the FP depicted the unique structures of secondary metabolites, such as cyclononasiloxane octadecamethyl, cercosporin, ethyl iso-allocholate, octadecane, 3-ethyl-5-(2-ethylbutyl), dasycarpidan-1-methanol (acetate), heptadecane, 9-hexyl-, phthalic acid-butyl, and octadecane, 3-ethyl-5-(2-ethylbutyl). The TGA analysis showed the thermal stability of FP and the initial weight loss in FP was observed at 277.29 °C. The 1H NMR and 13C NMR spectra of FP analysis demonstrated the various characteristic peaks presence of secondary metabolites. The XRD analysis at 2θ revealed distinct particles based on specific diffraction peaks. A set of six human bacterial pathogens, namely, the Gram-positive bacteria Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), and Bacillus subtilis (B. subtilis) and Gram-negative bacteria Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae), were utilized for screening. The FP exhibited promising antibacterial effects against both Gram-positive and Gram-negative bacterial organisms. The antibacterial spectrum of activity was greater for E. coli and B. subtilis than for K. pneumoniae.

Ananas comosus waste mediated highly stable Au NPs for environmental and biological applications

In contemporary times, the development of a cost-effective and sustainable platform for mitigating water pollutants is an ongoing challenge. Herein, Ananas comosus waste leaves mediated Au NPs have been synthesized after optimization of various reaction parameters and are found highly stable (for one year). The formation of Au NPs is confirmed by various characterization techniques i.e., UV–Visible spectrophotometer, FTIR, SAED, and HRTEM. UV–Vis spectrum displays the surface plasmon wavelength around 520 nm. HRTEM images show that the synthesized Au NPs are in narrow size distribution having size range between 20 and 30 nm with different shapes. Furthermore, they are employed as the effective catalyst, photocatalyst, and antimicrobial agents for the conversion reduction of 4-nitrophenol (20 min), methylene blue dye degradation (90 min), and Escherichia coli (inhibition zone 16 mm), and Bacillus subtilis (inhibition zone 13 mm) bacteria, respectively. Thus, this study offers a positive step in material research to prepare efficient photocatalyst, catalysts, and antimicrobial agents via a cost-effective and sustainable approach.

Synthesis, Antimicrobial Evaluation, and Molecular Docking of New Azole, Azine, Thiazole, and Chromene Derivatives

Novel heterocyclic compounds containing a benzothiazole moiety (2–16) were synthesized via the reaction of benzothiazole cyanoacetamide derivative (2) with different types of reagents. All compounds were characterized by 1H NMR, MS, and IR techniques. The newly synthesized compounds were examined for their in vitro antibacterial activity against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and fungi (Candida albicans) microorganisms. Compounds (5, 6, 7, and 15) are promising antimicrobial agents and could be the lead compounds for more potent drugs. Binding modes of the synthesized compounds were analyzed by docking studies that showed good binding scores against the diverse amino acids of the two selected proteins (PDB Codes – 2EXB and 3HUN). The conducted docking studies were found to be consistent with antimicrobial results. Thus, the results indicate that the designed structures can be a potential lead as antimicrobial agents.

Humic acid and growth promoting microorganisms in the germination and initial development of white sesame plants

The objective of this work was to verify the effect of humic acid application in association with the growth-promoting bacteria Azospirilum brasilense and Bacillus subtilis on seed germination and on the initial development of white sesame seedlings. The research was carried out in the Laboratory of Seed Technology and Matology (LaSeM), at the University of the State of Mato Grosso – Campus de Alta Floresta. The treatments were composed by the combination of doses of 0, 100, 200, 300, 400 and 500 mL 100 kg-1 of commercial product containing humic acid, composed of 18% of humic acid, in addition to treatment with the bacteria Azospirillum brasilense and Bacillus subtilis, in the same doses as humic acid. The variables analyzed were germination percentage, aerial and root length, fresh and dry mass of the roots. Humic acid showed promise in the cultivation of white sesame.

Effects of cholesterol on the mechanism of fengycin, a biofungicide

Fengycins are a class of antifungal lipopeptides synthesized by the bacteria Bacillus subtilis, commercially available as the primary component of the agricultural fungicide Serenade. They are toxic to fungi but far less to mammalian cells. One key difference between mammalian and fungal cell membranes is the presence of cholesterol only in the former; recent experimental work showed that the presence of cholesterol reduces fengycin-induced membrane leakage. Since our previous all-atom and coarse-grained simulations suggested that aggregation of membrane-bound fengycin is central to its ability to disrupt membranes, we hypothesized that cholesterol might reduce fengycin aggregation. Here, we test this hypothesis using coarse-grained molecular dynamics simulations, with sampling enhanced via the weighted ensemble method. The results indicate that cholesterol subtly alters the size distribution for fengycin aggregates, limits the lateral range of their membrane disordering, and reduces the ability of aggregates to bend the membrane. Taken together, these phenomena may account for cholesterol’s effects on fengycin activity.

Biotransformation of 2D Nanomaterials through Stimulated Bacterial Respiration-Produced Extracellular Reactive Oxygen Species: A Common but Overlooked Process

The biotransformation of 2D nanomaterials is still poorly understood, although their environmental fates are becoming an increasing concern with their broad applications. Here, we found that Ti3C2Tx nanosheets, a typical 2D nanomaterial, could be oxidized by reactive oxygen species (ROS) produced by both Gram-negative (Escherichia coli and Shewanella oneidensis) and Gram-positive (Bacillus subtilis) bacteria, with the formation of titanium dioxide (TiO2) on the nanosheet surfaces and impairment of structural integrity. Specifically, Ti3C2Tx nanosheets stimulated bacterial respiration Complex I, leading to increased generation of extracellular O2•- and the formation of H2O2 and •OH via Fenton-like reactions, which intensified the oxidation of the nanosheets. Surface modifications with KOH and hydrazine (HMH), especially HMH, could limit bacterial oxidation of the nanosheets. These findings reveal a common but overlooked process in which oxygen-respiring bacteria are capable of oxidizing 2D nanosheets, providing new knowledge for environmental fate evaluation and future design of functional 2D nanomaterials.

Towards on-demand photocatalysis: Controlling the operation of a photocatalytic reactor based on real-time, automatic monitoring of toxicity towards the working bacteria of a proceeding bioreactor

• Real-time measuring unit of input stream toxicity to bioreactors was developed. • The automatic sensing unit is based on viability assay using bacillus subtilis . • The sensing unit was integrated with a photocatalytic reactor. • An autonomous control of the work-load of a photocatalytic reactor was achieved. • The approach can be utilized to any AOP-biotreatment tandem configuration. Wastewater streams contain a large number of contaminants, part of which can be quite toxic for the working bacteria in bioreactors, thus hampering its efficiency. In such cases, pretreatment by an Advanced Oxidation Process (AOP) might be needed. Since, in general, biotreatment is more economic than AOP, it is sensible to design the integrated system in a manner that would reduce the load on the AOP as much as possible. This is a very challenging task, since the type and the concentration of the toxic compounds constantly varies over time. The problem is aggravated by lack of inexpensive and fast technologies that are able to evaluate the toxicity under conditions in which the nature of the toxic compounds is unknown. Here we report on the developing of a unit that automatically measures the extent by which polluted water might put at risk a biological treatment unit. The sensing unit monitors in real time the viability of the reporting bacteria Bacillus Subtilis , using resazurin. The toxic compounds were modelled by three antibiotics (chloramphenicol, tetracycline and ciprofloxacin). The potential of embedding the sensing unit in a multi-technology system (AOP-biological) was demonstrated by connecting the sensing unit to a photocatalytic reactor and controlling the number of operating lamps in the photocatalytic reactor autonomously according to predetermined toxicity setpoint. The approach can be easily applied to almost any AOP-biotreatment tandem system, while altering any controllable parameter (residence time, light, etc.) of the AOP unit according to needs.

The Addition of Different Adsorbents In SA-PVA Matrix For Bacillus Subtilis Immobilization on Methylene Blue Decolorization

Wastewater which is not handled by a proper treatment before released in the water body, can cause damage for aquatic biota and its environment. MB is a synthetic textile dye which is toxic and difficult to degrade. Bioremediation by decolorization using microbes such as bacteria is one of the best methods for dye removal. By immobilizing Bacillus subtilis bacterium in an appropriate matrix, it could have more advantage on dye decolorization than by free cell only. The sodium alginate (SA) and polyvinyl alcohol (PVA) are well known as good matrix for decolorization. Besides the addition of B. subtilis in the SA-PVA matrix, the addition of adsorbents could enhance the decolorization. In this study, different adsorbents: bentonite, activated charcoal, kaolin, and corncob powder were investigated for influencing MB decolorization by immobilized B. subtilis in SA-PVA matrix. The result showed that the highest MB decolorization was reached by SA-PVA-B. subtilis with the presence of activated charcoal by approximately 88% of 100 mg/L, followed by the addition of bentonite (82%), kaolin (80%), and corncob powder (79%). The MB decolorization by SA-PVA-Activated charcoal-B. subtilis reached optimum condition at temperature 35 °C, 24 h incubation time in static condition.

Stimulation of the Protective Mechanisms of Solanum tuberosum by the Bacteria Bacillus subtilis and Chitooligosaccharides upon Infection with Phytophthora infestans

Stimulation of the Protective Mechanisms of Solanum tuberosum by the Bacteria Bacillus subtilis and Chitooligosaccharides upon Infection with Phytophthora infestans

Elucidating Therapeutic and Biological Potential of Berberis baluchistanica Ahrendt Bark, Leaf, and Root Extracts.

Berberis baluchistanica Ahrendt is a medicinal plant known to have potential for the treatment of various diseases. In the present study, the ethanolic extracts of the bark, leaves, and roots of B. baluchistanica plant were evaluated for in vitro antimicrobial, anti-leishmanial, anticancer, and anti-inflammatory activities. The antibacterial and antifungal activities were determined by agar mix and agar well diffusion method. All extracts showed potential activity against the target bacteria (Bacillus subtilis, Bacillus licheniformis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Rhodococcus erythropolis, Salmonella typhi, and Staphylococcus aureus) and fungal strains (Aspergillus flavus, Aspergillus niger, and Mucor mucedo). S. aureus proved to be the most sensitive strain for each extract, with a maximum zone of inhibition for bark at 23 ± 0.12 mm, for leaves at 22 ± 0.36 mm, and for root extracts at 20.21 ± 0.06 mm). The minimum inhibitory concentration values of B. baluchistanica bark, leaves, and roots for different target bacterial strains ranged from 1.56 to 25 mg ml–1, and the minimum bactericidal concentrations were in the range of 3.12 to 25 mg ml–1, respectively. The root extract possessed potent antifungal activity against A. flavus with 83% of growth inhibition, A. niger with 80%, and M. mucedo with 73%. The bark extract was found active against M. mucedo with 86% of inhibition, followed by 70% against A. flavus and 60% against A. niger. The leaf extract showed a significant response by 83% inhibition against M. mucedo, followed by A. flavus and A. niger with 73 and 72% inhibition, respectively. In an anti-leishmanial bioassay, the inhibitory concentration (IC50) was observed for each extract against Leishmania major. The bark showed good activity (IC50 = 4.95 ± 0.36 mg/ml), followed by the roots (IC50 = 7.07 ± 0.18 mg/ml) and the leaves (IC50 = 8.25 ± 0.29 mg/ml). An evaluation of anticancer activity was done by using MTT cell assay against HeLa cell line. Upon comparing the values of each extract to the standard, it was revealed that the ethanolic bark extract showed the highest anticancer activity with IC50 = (12 ± 0.15 μg/ml), followed by the roots (14 ± 0.15 μg/ml) and the leaves (17 ± 0.21 μg/ml), respectively. The anti-inflammatory assay was undertaken by the inhibition of albumin denaturation activity, proteinase inhibitory activity, and heat-induced hemolysis activity. The IC50 value for protein denaturation of the bark was IC50 = 0.64 ± 0.25 mg/ml, followed by the roots (0.67 ± 0.21 mg/ml) and the leaves (0.73 ± 0.13 mg/ml). The proteinase inhibitory activity of the bark extract was IC50 = 0.55 ± 0.12 mg/ml, followed by the leaves (0.62 ± 0.23 mg/ml) and the roots (0.69 ± 0.15 mg/ml), respectively. For heat-induced hemolysis assay, the bark showed the lowest IC50 value (0.48 ± 0.15 mg/ml) compared to the leaves (0.52 ± 0.35 mg/ml) and the roots (0.58 ± 0.05 mg/ml) of the plant. All analyzed parts of the B. baluchistanica plant showed significant biological activities which make the plant medicinally important and a good candidate for the isolation of antimicrobial, inflammatory, and anticancer compounds. Further studies may lead us to determine the active compounds responsible for the biological activities of the plant extracts.

Ionic Liquid-Assisted Fabrication of Bioactive Heterogeneous Magnetic Nanocatalyst with Antioxidant and Antibacterial Activities for the Synthesis of Polyhydroquinoline Derivatives.

Antibacterial materials have obtained much attention in recent years due to the presence of hazardous agents causing oxidative stress and observation of pathogens. However, materials with antioxidant and antibacterial activities can cause toxicity due to their low biocompatibility and safety profile, urging scientists to follow new ways in the synthesis of such materials. Ionic liquids have been employed as a green and environmentally solvent for the fabrication of electrically conductive polymers. In the present study, an antibacterial poly(p-phenylenediamine)@Fe3O4 (PpPDA@Fe3O4) nanocomposite was fabricated using [HPy][HSO4] ionic liquid. The chemical preparation of PpPDA@Fe3O4 nanocomposite was initiated through the oxidative polymerization of p-phenylenediamine by ammonium persulfate in the presence of [HPy][HSO4]. The PpPDA@Fe3O4 nanocomposite exhibited antibacterial properties against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The PpPDA@Fe3O4 nanocomposite was employed as a heterogeneous nanocatalysis for one-pot synthesis of polyhydroquinoline derivatives using aromatic aldehyde, dimedone, benzyl acetoacetate, and ammonium acetate. Polyhydroquinoline derivatives were synthesized in significant yields (90–97%) without a difficult work-up procedure in short reaction times. Additionally, PpPDA@Fe3O4 nanocatalyst was recycled for at least five consecutive catalytic runs with a minor decrease in the catalytic activity. In this case, 11 derivatives of polyhydroquinoline showed in vitro antioxidant activity between 70–98%.

Production of antimicrobial peptide arasin-like Sp in Escherichia coli via an ELP-intein self-cleavage system

Antibiotic resistance is a major public health threat to both humans and animals. There is an urgent need for antimicrobial agents with novel modes of action. Antimicrobial peptides (AMPs) with broad-spectrum antimicrobial activity become the ideal alternative to traditional antibiotics. Here, the ELP-intein self-cleavage system was used to produce antimicrobial peptide arasin-likeSp in Escherichia coli. The tagged target protein (ELP-intein-arasin-likeSp) was mainly expressed in soluble, separated from cell lysates by the inverse transition cycling (ITC), and the arasin-likeSp was further purified by the self-cleavage of intein and the second round of ITC. The final yield of arasin-likeSp was about 3.56 mg/L. Purified arasin-likeSp exhibited significant antibacterial activities against the Gram-positive Bacillus subtilis and Gram-negative Vibrio harveyi bacteria. FE-SEM and PI staining analysis revealed that the arasin-likeSp treatment altered the morphology and membrane permeability of Bacillus subtilis and Vibrio harveyi. Collectively, these data suggest that arasin-likeSp is a candidate AMP for effective inhibition of Vibrio harveyi, a significant bacterial pathogen infecting marine fish and invertebrates. The ELP-intein self-cleavage system described here is a low-cost, simple and potential method for producing antimicrobial peptides, which lays foundations for the large-scale production of antimicrobial peptides in the future.

Isolation of Biofilm Producing Bacteria from Stool Samples and Their Antibiogram

Aim: Bacterial biofilm formation is a menacing attribute that has been linked to a rise in antibiotic resistance. The aim of this study was to isolate biofilm-producing bacteria from stool samples and their antibiogram. Study Design: The study involved laboratory research, statistical analysis and interpretation of the data. Place and Duration of Study: The research was carried out in three (3) hospital facilities. They are University of Port Harcourt Teaching Hospital (UPTH), Meridian Hospital D/line branch (MRD1), and Meridian Hospital Ikoku branch (MDR2). Specimens were gathered within three (3) months, and analyses were performed. Methodology: 45 stool specimens were collected from the three (3) hospitals. The specimens were correctly labelled with the sampling date and time. Standard microbiological procedures were performed on the collected specimens, including plate counts, identification, biofilm screening, sensitivity testing, extended spectrum beta lactamase phenotypic screening, and molecular characterization of the isolates. Results: The total heterotrophic bacterial counts ranged from 6.2 to 8.2 x107 cfu/g, total coliform counts ranged from 3.2 to 4.1 x106 cfu/g and faecal coliform counts ranged from 1.3 to 1.4 x105 cfu/g. There was no significant difference at (p≤0.05) in the total heterotrophic bacterial counts, total and faecal coliform counts between the hospitals sampled. A total of Thirty-two (32) bacterial isolates were identified in stool specimens, with 20 (62.5%) of them being biofilm producers. Staphylococcus 30%, 35% Escherichia coli, 25% Enterococcus and 10% Bacillus species were detected among biofilm bacteria. Biofilm isolates showed a variety of susceptibility patterns and antibiotic resistance was found in biofilm bacteria. Most bacterial intestinal tract infections from patients and hospitals investigated can be treated with ofloxacin, Gentamycin, Imipenem, and Nitrofurantoin. TET A and CTX-M genes, were reported in Bacillus subtilis and Escherichia coli biofilm bacteria as possible genes that could confer antibiotic resistance.The existence of the icaD and papC genes in Bacillus subtilis and Escherichia coli has been discovered to be probable determinants that impart biofilm forming abilities, according to genomic studies. Conclusion: The existence of biofilm-producing bacteria in patients’ stools, as well as their antibiotic resistance, was observed in this study. Ceftazidime (third generation cephalosporin) resistance was found in both biofilm and non-biofilm bacteria. This research reveals that ofloxacin, Gentamycin, Imipenem, and Nitrofurantoin are the drugs of choice for bacterial intestinal tract infections caused by Escherichia coli, Staphylococcus, Enterococcus, and Bacillus species. As a result, proper infection control techniques and therapeutic recommendations for proven infections should be swiftly implemented.

Highly hydrophilic quaternary ammonium salt containing organotin (IV) carboxylate for visualization of antibacterial action and multi-photon absorption activity

Antibiotics with multi-photon absorption are expected to play an important role in biomedicine. A novel mononuclear organotin complex RJSnBu3 is designed, synthesized and systematically studied in this work. It is found that RJSnBu3 has a suitable three-photon active cross section under 1400 nm excitation (NIR II region). RJSnBu3 can inhibit the growth of Galanz-positive bacteria (Bacillus subtilis) and Galanz-negative bacteria (Escherichia coli) in the antibacterial screening. Compared to kanamycin, RJSnBu3 has excellent inhibitory effect on Bacillus subtilis. Importantly, the results of in vitro nucleic acid titration and two-photon bacterial imaging shows that RJSnBu3 can damage the bacteria cell membrane. The cytosol flows out when RJSnBu3 binds to DNA, causing the bacteria to die. The multi-photon in vivo imaging results reveal that RJSnBu3 could be ultra-sensitive for detection of colitis mice. These results provide that RJSnBu3 has promising applications for multiphoton imaging and the development of specific antibacterial drugs.

Effective treatment of aquaculture wastewater with mussel/microalgae/bacteria complex ecosystem: a pilot study

The discharge of aquaculture wastewater increased significantly in China. Especially, high content of nitrogen and phosphorus in wastewater could destroy the receiving water environment. To reduce the pollution of aquaculture wastewater, farmed triangle sail mussel (Hyriopsis cumingii) was proposed to be cultivated in the river. This was the first time that bacteria (Bacillus subtilis and Bacillus licheniformis) and microalgae (Chlorella vulgaris) were also used and complemented ecosystem functions. The pollutants in wastewater were assimilated by Chlorella vulgaris biomass, which was then removed through continuous filter-feeding of Hyriopsis cumingii. While, Bacillus subtilis and Bacillus licheniformis enhanced the digestive enzyme activities of mussel. It demonstrated that approximately 4 mussels/m3 was the optimal breeding density. Under such condition, orthogonal experiment indicated that the dose of Bacillus subtilis, Bacillus licheniformis, and Chlorella vulgaris should be 0.5, 1, and 2 mL respectively. Compared with mussel, mussel/microalgae, mussel/bacteria system, treatment ability of the mussel/microalgae/bacteria system in batch experiment was better, and 94.67% of NH3-N, 92.89% of TP and 77.78% of COD were reduced after reaction for 6 days. Finally, 90 thousand mussels per hectare of water were cultivated in Kulv river in China, and the field experiment showed that water quality was significantly improved. After about 35 days of operation, NH3-N, TN, TP and COD concentration were maintained around 0.3, 0.8, 0.3, and 30 mg/L respectively. Therefore, the mussel/microalgae /bacteria system in this study showed a sustainable and efficient characteristic of aquaculture wastewater bioremediation.

Sustained Control of Pyruvate Carboxylase by the Essential Second Messenger Cyclic di-AMP in Bacillus subtilis.

ABSTRACTIn Bacillus subtilis and other Gram-positive bacteria, cyclic di-AMP is an essential second messenger that signals potassium availability by binding to a variety of proteins. In some bacteria, c-di-AMP also binds to the pyruvate carboxylase to inhibit its activity. We have discovered that in B. subtilis the c-di-AMP target protein DarB, rather than c-di-AMP itself, specifically binds to pyruvate carboxylase both in vivo and in vitro. This interaction stimulates the activity of the enzyme, as demonstrated by in vitro enzyme assays and in vivo metabolite determinations. Both the interaction and the activation of enzyme activity require apo-DarB and are inhibited by c-di-AMP. Under conditions of potassium starvation and corresponding low c-di-AMP levels, the demand for citric acid cycle intermediates is increased. Apo-DarB helps to replenish the cycle by activating both pyruvate carboxylase gene expression and enzymatic activity via triggering the stringent response as a result of its interaction with the (p)ppGpp synthetase Rel and by direct interaction with the enzyme, respectively.

Synthesis and bioevluation of BIS (Indolyl) methane derivatives using copper halide catalyst

A mild and an efficient method catalyzed by copper iodide in TMEDA as solvent was used for the synthesis of bis(indolyl) methanes through a cascade process between indole and substituted aromatic aldehyde to produce the corresponding bis (indolyl) alkanes in moderate to good yields under reflux conditions. All structures of the desired products were evaluated using spectroscopic techniques 1H NMR, 13C NMR spectroscopy and LCMS. The structure of the compounds was determined by elemental analysis. The antibacterial activity of newly synthesized compounds was investigated against gram positive bacteria (Escherichia coli and Pseudomonas) and gram negative bacteria (Bacillus subtilis and Staphylococcus aureus). Anti fungal activity of some newly synthesized compounds was examined against three pathogens such as Aspergillus Niger, Aspergillus favus and Candida albicans.