Simple and Rapid Method for Detecting Biofilm Forming Bacteria

Diversity and distribution of culturable fouling bacteria in typical mariculture zones in Daya Bay, South China

The diversity and distribution of culturable fouling bacteria in shellfish, fish and non-mariculture zones in Daya Bay were investigated by using a traditional culture-dependent approach combined with an analysis of bacterial 16S rRNA gene sequences. A total of 129 isolates of fouling bacteria belonging to 37 species in 25 genera were collected and identified, which indicated that the three different mariculture zones harbored abundant and diverse fouling bacterial community. At the genus level, Pseudomonas, Arcobacter and Curtobacterium dominated the fouling bacterial community. Moreover, approximately 46% of the 37 representative isolates could form biofilms. After comparing the diversity and distribution of the biofilm-forming bacteria in three different mariculture zones, it was concluded that the ratios of biofilm-forming bacteria in shellfish (68.4%) and fish (63.4%) in mariculture zones were much greater than those in non-mariculture (42.0%) zone. These results provide important information, for the first time, regarding the fouling bacterial community in typical mariculture zones in South China, which will establish a foundation to develop strategies for biofilm control and disease defense.

Differential Multi-cellularity Is Required for the Adaptation for Bacillus licheniformis to Withstand Heavy Metals Toxicity

Bacillus licheniformis is a multi-metal tolerant bacteria, isolated from the paddy rhizospheric soil sample. Upon the multiple metal toxicity, B. licheniformis altered their phenotypic/morphogenesis. Here we examined the effects of cadmium (Cd2+), chromium (Cr2+), and mercury (Hg2+) on the morphogenesis of B. licheniformis in comparison to control. We found that the ability of bacteria to grow effectively in presence of cadmium and chromium comes at a cost of acquiring cell density-driven mobility and reformation of filamentous to donut shape respectively. In particular, when bacteria grown on mercury it showed the bacteriostatic strategy to resist mercury. Furthermore, the findings suggest a large variation in the production of exo-polysaccharides (EPS) and suggest the possible role of EPS in gaining resistance to cadmium and chromium. Together this study identifies previously unknown characteristics of B. licheniformis to participate in bioremediation and provides the first evidence on positive effects of bacterial morphogenesis and the involvement of EPS in bacteria to resisting metal toxicity.

Bacterial signalling mechanism: An innovative microbial intervention with multifaceted applications in microbial electrochemical technologies: A review

Microbial electrochemical technologies (METs) are a set of inventive tools that generate value-added by-products with concomitant wastewater remediation. However, due to the bottlenecks, like higher fabrication cost and inferior yield of resources, these inventive METs are still devoid of successful field-scale implementation. In this regard, application of quorum sensing (QS) mechanism to improve the power generation of the METs has gained adequate attention. The QS is an intercellular signalling mechanism that controls the bacterial social network in its vicinity via the synthesis of diffusible signal molecules labelled as auto inducers, thus ameliorating yield of valuables produced through METs. This state-of-the-art review elucidates different types of QS molecules and their working mechanism with the special focus on the widespread application of QS in the field of METs for their performance enhancement. Thus, this review intends to guide the researchers in rendering scalability to METs by integrating innovative QS mechanisms into them.

Improvisation and Evaluation of Laterosporulin Coated Titanium Surfaces for dental Applications: An In Vitro Investigation

Despite recent improvement in implant survival rates, there remains a significant demand for enhancing the long-term clinical efficacy of titanium (Ti) implants, particularly for the prevention of peri-implantitis. Bioactive substances such as antimicrobial peptides are emerging as effective alternatives for contemporary antimicrobial agents used in dental health care. Current research work was focused to use laterosporulins that are non-haemolytic cationic antimicrobial peptides from Brevibacillus spp. for coating commercially available Ti discs. The coated Ti surfaces were evaluated in vitro for biofilm formation by two dental plaque isolates Streptococcus gordonii strain DIGK25 and S. mutans strain DIGK119 as representatives of commensal and pathogenic streptococci respectively. The biofilm inhibition was ascertained with replicated experiments on hydroxyapatite discs and confirmed by florescence microscopy. The laterosporulin coated Ti discs showed significantly reduced biofilm formation by oral streptococci and displayed promising potential to enhance the antibacterial surface properties. Such improvised Ti surfaces may curb the menace of oral streptococcal biofilm formation on dental implants and the associated implant failures.

Taxonomically Characterized and Validated Bacterial Species Based on 16S rRNA Gene Sequences from India During the Last Decade

Microbial taxonomy dealing with identification and characterization of prokaryotes like bacteria and archaea has always been a major area of research all over the world. Exploring diversity of microbes and description of novel species with different genes and secondary compounds is of utmost importance for better future and sustenance of life. India having an enormous range of ecosystems and diverse species inhabiting these niches is considered to be one of the richest biodiversity regions of the world. During the last decade, with newer methodologies and better technology, the prokaryotic taxonomy from India has extended our inventory of microbial communities in specific niches. However, there still exist some limitations in classifying the microbes from India as compared to that is done world-over. This review enlists the taxonomic description of novel taxa of prokaryotes from India in the past decade. A total of 378 new bacterial species have been classified from different habitats in India in the last ten years and no descriptions of archaeal species is documented till date.

Aligning Microbial Biodiversity for Valorization of Biowastes: Conception to Perception

Generation of biowastes is increasing rapidly and its uncontrolled, slow and persistent fermentation leads to the release of Green-house gases (GHGs) into the environment. Exploration and exploitation of microbial diversity for degrading biowastes can result in producing diverse range of bioactive molecules, which can act as a source of bioenergy, biopolymers, nutraceuticals and antimicrobials. The whole process is envisaged to manage biowastes, and reduce their pollution causing capacity, and lead to a sustainable society. A strategy has been proposed for: (1) producing bioactive molecules, and (2) achieving a zero-pollution emission by recycling of the GHGs through biological routes.

Curcumin Encapsulated PEGylated Nanoliposomes: A Potential Anti-Infective Therapeutic Agent

Exploration of novel bioactive molecules or potentiation of the existing bioactive molecules is necessary to reduce the burden of the infectious diseases for the better human health. Curcumin is a promising molecule with huge therapeutic potential. Despite high bioactivity, its therapeutic suitability is shadowed by poor bioavailability, limited aqueous solubility, and short shelf life. Nanotechnology has generated new avenues to overcome these challenges. In the current study polymer assisted nanoliposomes, PEGylated Curcumin nanoliposomes with good loading efficiency were prepared. These particles have shown 1000 fold enhanced curcumin hydrophilicity and tenfold higher stability. In vitro release kinetic indicates two fold higher curcumin release in the simulated gastric and intestinal environment. Various bioactivity assays have confirmed enhanced bioactivity of nanocurcmin in comparison of the native curcumin. PEGylated Curcumin nanoliposomes could be employed for treating various diseases.

Bioremediation of wastewater through a quorum sensing triggered MFC: A sustainable measure for waste to energy concept

A mission for fast advancement has constrained us to unpredictably tap various natural assets. The reckless utilisation of fossil fuels led unmanageable wastes which have greatly affected our health and environment. Endeavours to address these difficulties have conveyed to the frontal area certain creative natural solutions particularly the utilisation of microbial digestion systems. In the previous two decades, the microbial fuel cell (MFC) innovation has caught the consideration of the researchers. The MFCs is a kind of bio-electrochemical framework with novel highlights, for example, power production, wastewater treatment, and biosensor applications. Lately, dynamic patterns in MFC inquire about on its synthetic, electrochemical, and microbiological perspectives have brought about its observable applications. The MFCs have begun as a logical interest, and in numerous regards, these remaining parts to be the situation. This is especially a result of the multidimensional uses of this eco-accommodating innovation. The innovation relies upon the electroactive microorganisms, prominently known as exoelectrogens. In the first place, it is the main innovation that can create energy out of waste, without the contribution of outer/extra energy. Modification of electrodes with nanomaterials, for example, gold nanoparticles and iron oxide nanoparticles or pretreatment techniques, for example, sonication and autoclave disinfection have indicated promising outcomes in improving MFC execution for power generation and wastewater treatment. The MFC innovation has been likewise explored for the remediation of different heavy metals and hazardous components, and to recognize the poisonous components in wastewater. What's more, the MFCs can be adjusted into microbial electrolysis cells to produce hydrogen energy from different natural sources. This article gives a thorough and cutting-edge appraisal of the novel magnitudes of the MFC.

Antimicrobial Activity of Amino-Derivatized Cationic Polysaccharides

To improve the antimicrobial property of chitosan, water-soluble chitosan modified in their quaternary ammonium groups were synthesized. The antimicrobial properties were evaluated against Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Candida tropicalis. The activities increased with increasing cationic charges and the length of the alkyl chain as follows amino-chitosan, dimethylaminoethyl-chitosan, dimethylpropyl amino-chitosan, dimethylamino-1-propyl-chitosan, diethylaminoethyl (DEAE)-chitosan, and quaternized DEAE-chitosan. The modified cationic chitosans showed high antimicrobial property against B. subtilis-Gram-positive bacteria, but were less active towards yeast (C. tropicalis and S. cerevisiae) and E. coli-Gram-negative bacteria. The simple structure of the Gram-positive bacteria may explain why the cationic chitosan derivatives are more active towards B. subtilis than yeast and E. coli. The target sites of the chitosan derivatives are assumed to be the cytoplasmic membranes of microorganisms. The antimicrobial activities were strongly dependent on the cationic charge and the molecular weight. It can be suggested that these cationic chitosan derivatives have potential as antimicrobial agents.

Contraceptive Sperm Agglutinating Proteins Identified in Staphylococcus warneri, Natural Microflora of an Infertile Woman

Staphylococcus warneri, isolated from the cervix of an adult female with unexplained infertility, was found to agglutinate human spermatozoa in vitro leading to their death. A genomic library of S. warneri was generated using pSMART-Escherichia coli vector-host system. Approximately 3500 transformants were screened and four showed sperm agglutinating activity. Sperm agglutinating proteins (SAPs) were partially purified from the positive transformants and were found to agglutinate sperms in vitro. Cloned ORFs in positive transformants were sequenced and ORF finder identified them as endonuclease, accessory secretory protein-Asp1, accessory secretory protein-Asp2 and signal transduction protein. Mannose was found to competitively inhibit sperm agglutination, indicating that SAPs in S. warneri bind to mannose in glycoprotein receptors on the surface of sperms for agglutination. This is the first report on identification of SAPs which may be responsible for unexplained infertility in women and may be used as contraceptive agents.

Inhibition of Staphylococcus aureus and Pseudomonas aeruginosa Biofilm and Virulence by Active Fraction of Syzygium cumini (L.) Skeels Leaf Extract: In-Vitro and In Silico Studies

Syzygium cumini L. Skeels (Myretacae family) is a native plant of the Indian subcontinent which has wide socio-economical importance and is well known for its ant diabetic activity. The present study aimed to investigate the antibiofilm activity of purified fraction (EA) from S. cumini leaf extract against P. aeruginosa and S. aureus. The EA did not show any effect on growth of P. aeruginosa and S. aureus at the concentration of 900 µg/ml. At this concentration EA showed biofilm inhibition up to 86 ± 1.19% (***P < 0.0001) and 86.40 ± 1.19% (***P < 0.0001) in P. aeruginosa and S. aureus respectively. SEM examination also confirmed the reduction in biofilm formation. Further EA also disrupted some virulence phenotypes in P. aeruginosa and S. aureus. Bioactive compounds detected by GC-MS showed their possible molecular interaction with RhlG/NADP active-site complex (PDB ID: 2B4Q), LasR-TP4 complex (PDB ID: 3JPU) and Pseudaminidase (PDB ID: 2W38) from P. aeruginosa. The in vitro biofilm inhibition, virulence factor inhibition and the mode of interaction of bioactive components in Syzygium cumini with QS proteins of bacteria reported in this study might be an affordable and effective alternative method of controlling quorum sensing/biofilm-associated infections.

Autochthonous Bacillus licheniformis: Probiotic potential and survival ability in low-fishmeal extruded pellet aquafeed

In recent years, Bacillus spp. have garnered attention as probiotic supplements in aquafeed owing to the production of heat stable and low pH resistant spores. Herein, we isolated and characterized an autochthonous Bacillus licheniformis KCCM 43270 from the intestine of olive flounder (Paralichthys olivaceus) for supplementation in low‐fishmeal extruded aquafeeds. The KCCM 43270 was screened based on amylase, protease, cellulase, and lipase as well as non‐hemolytic activities. The isolate was able to grow in carboxymethyl cellulose (CMC), xylan, and soybean meal (SBM) when used as a single carbon source in the minimal nutrient M9 medium. The KCCM 43270 spores displayed complete survival in acid (pH 2.5) and bile (0.3%, w/v) for 3 hr, strong biofilm formation, and nearly 50% adhesion with intestinal mucus. The spores of the isolate also showed significant survival ability at 80, 90, 100°C for 60, 30, and 1 min, respectively. In addition, the spores in a blend of SBM complex carrier showed significant heat stability at 120°C for 5 min and under different drying conditions. Furthermore, the spores also survived the extrusion process during low‐fishmeal aquafeed manufacturing, implying the potential application of B. licheniformis KCCM 43270 in aquafeed industry.

Fish Gut Microbiome: Current Approaches and Future Perspectives

In recent years, investigations of microbial flora associated with fish gut have deepened our knowledge of the complex interactions occurring between microbes and host fish. The gut microbiome not only reinforces the digestive and immune systems in fish but is itself shaped by several host-associated factors. Unfortunately, in the past, majority of studies have focused upon the structure of fish gut microbiome providing little knowledge of effects of these factors distinctively and the immense functional potential of the gut microbiome. In this review, we have highlighted the recently gained insights into the diversity and functions of the fish gut microbiome. We have also delved on the current approaches that are being employed to study the fish gut microbiome with an aim to collate all the knowledge gained and make accurate conclusions for their application based perspectives. The literature reviewed indicated that the future research should shift towards functional microbiomics to improve the maximum sustainable yield in aquaculture.

Synthesis, Antimicrobial and Antioxidant Activity of Pyrazole Based Sulfonamide Derivatives

A series of new sulfonamides have been synthesized from Ampyrone with different benzene sulfonyl chlorides to yield the N-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) benzenesulfonamides (4a-e). All synthesized compounds were characterized on the basis of FTIR, 1H NMR, and 13C NMR, and also by the aid of mass spectral data. Further, all synthesized compounds have studied for their in vitro antimicrobial activities against selected bacterial as well as fungal strains by the agar well diffusion method. Free radical scavenging activity has been investigated by using DPPH method. Among all the synthesized compounds, 4b, 4d, and 4e exhibited significant antimicrobial and antioxidant activities.

Wastewater: A Potential Bioenergy Resource

Wastewaters are a rich source of nutrients for microorganisms. However, if left unattended the biodegradation may lead to severe environmental hazards. The wastewaters can thus be utilized for the production of various value added products including bioenergy (H₂ and CH₄). A number of studies have reported utilization of various wastewaters for energy production. Depending on the nature of the wastewater, different reactor configurations, wastewater and inoculum pretreatments, co-substrate utilizations along with other process parameters have been studied for efficient product formation. Only a few studies have reported sequential utilization of wastewaters for H₂ and CH₄ production despite its huge potential for complete waste degradation.

Bioprocessing of Biodiesel Industry Effluent by Immobilized Bacteria to Produce Value-Added Products

Biodiesel industrial effluent rich in crude glycerol (CG) was processed to produce value-added product. Under continuous culture system, Bacillus amyloliquefaciens strain CD16 immobilized within its biofilm, produced 3.2 L H₂/day/L feed, over a period of 60 days at a hydraulic retention time of 2 days. The effective H₂ yield by B. amyloliquefaciens strain CD16 was 165 L/L CG. This H₂ yield was 1.18-fold higher than that observed with non-biofilm forming Bacillus thuringiensis strain EGU45. Bioprocessing of the effluent released after this stage, by recycling it up to 25% did not have any adverse effect on H₂ production by strain EGU45; however, a 25% reduction in yield was recorded with strain CD16. Biofilm forming H₂ producers thus proved effective as self-immobilizing system leading to enhanced process efficiency.