Inhibition of Quorum Sensing and Virulence Factors of Pseudomonas aeruginosa by Biologically Synthesized Gold and Selenium Nanoparticles

The development of microbial resistance requires a novel approach to control microbial infection. This study implies the microbial synthesis of nanometals and assessment of their antivirulent activity against Pseudomonas aeruginosa. Streptomyces isolate S91 was isolated from soil with substantial ability for growth at high salts concentrations. The cell-free supernatant of S91was utilized for the synthesis of Au-NPs and Se-NPs. The 16S rRNA sequence analysis of Streptomyces S91 revealed that S91 had a high similarity (98.82%) to Streptomyces olivaceous. The biosynthesized Au-NPs and Se-NPs were characterized using a UV-Vis spectrophotometer, dynamic light scattering, transmission electron microscopy, energy dispersive X-ray diffraction and Fourier-transform infrared spectroscopy. The quorum sensing inhibitory (QSI) potential of Au-NPs and Se-NPs and the antivirulence activity was examined against P. aeruginosa. The QSI potential was confirmed using RT-PCR. The synthesized Au-NPs and Se-NPs were monodispersed spherical shapes with particle size of 12.2 and 67.98 nm, respectively. Au-NPs and Se-NPs eliminated QS in P. aeruginosa at a concentration range of 2.3–18.5 µg/mL for Au-NPs and 2.3–592 µg/mL for Se-NPs. In addition, Au-NPs and Se-NPs significantly inhibited QS-related virulence factors, such as pyocyanin, protease and, elastase in P. aeruginosa. At the molecular level, Au-NPs and Se-NPs significantly suppressed the relative expression of QS genes and toxins. Hence, the biosynthesized Au-NPS and Se-NPS could be substantial inhibitors of QS and virulence traits of P. aeruginosa.

Isolation, purification and characterization of mannan degrading enzyme from a new isolate Acinetobacter baummanni

A mannan-degrading microbe was isolated from rotting porang tubers (Amorphophallus muelleri Blume). Molecular identification using 16S-rRNA sequence analysis revealed that the isolate showed 99.67% similarity with Acinetobacter baummanni. A crude enzyme from ammonium sulphate precipitation was used for preliminary characterization. The characterization results showed that the enzyme activity is optimum at 45 °C, and stable at 35-50 °C, while the optimum pH is 7, and stable at pH 5-7. The substrate with the highest relative activity was found in guar gum which was 137.512%. The enzyme activity was inhibited by Ca, Na, K ions, and increased by Mn2+ ions.

Characterization of Bacterial Community of Rumen in Dairy Cows With Laminitis

Background: Laminitis- an inflammation of lamella, could cause great economic loss to dairy industry, which has attracted wide attention around the world. In recent years, microbiota is considered as one of the vital parts that played significant role in various diseases processes. However, current studies are far from sufficient. Aim of this study is to explore the characteristics of ruminal microbiota in laminitis cows. Methods: The serum of bovines with or without laminitis was collected to detect concentrations of lipopolysaccharide (LPS), lactic acid, and histamine, and the ruminal fluid was collected for 16S rRNA sequence analysis. Results: The results showed that a significant increase in LPS and lactic acid levels in laminitis group comparing to control group cows. In addition, the higher abundance of bacteria that -riches acid-enhancing metabolites, namely, Candidatus Saccharimonas, Saccharofermentans, Erysipelotrichaceae UCG-009, Erysipelotrichaceae UCG-008, Clostridium papyrosolvens and Ruminococcaceae bacterium AE2021 were detected in the rumen fluid from laminitis bovines. Conclusions: This article confirmed that difference of rumen microbiota were occurred in rumen between health and laminitis bovines. The elevated abundance of bacteria that riches acid- enhancing metabolites, as well as increased the concentration of lactic acid and LPS could be harmful factors to bovines and increase risks of laminitis.

Multipotential Alkaline Protease From a Novel Pyxidicoccus sp. 252: Ecofriendly Replacement to Various Chemical Processes

A newly isolated alkaline protease-producing myxobacterium was isolated from soil. The strain was identified as Pyxidicoccus sp. S252 on the basis of 16S rRNA sequence analysis. The extracellular alkaline proteases produced by isolate S252 (PyCP) was optimally active in the pH range of 11.0–12.0 and temperature range of 40–50°C The zymogram of PyCP showed six caseinolytic protease bands. The proteases were stable in the pH range of 8.0–10.0 and temperature range of 40–50°C. The activity of PyCP was enhanced in the presence of Na+, Mg2+, Cu2+, Tween-20, and hydrogen peroxide (H2O2) (hydrogen peroxide), whereas in Triton X-100, glycerol, ethylenediaminetetraacetic acid (EDTA), and Co2+, it was stable. PyCP showed a potential in various applications. The addition of PyCP in the commercial detergent enhanced the wash performance of the detergent by efficiently removing the stains of tomato ketchup and coffee. PyCP efficiently hydrolyzed the gelatin layer on X-ray film to release the embedded silver. PyCP also showed potent dehairing of goat skin and also efficiently deproteinized sea shell waste indicating its application in chitin extraction. Thus, the results of the present study indicate that Pyxidicoccus sp. S252 proteases have the potential to be used as an ecofriendly replacement of chemicals in several industrial processes.

Isolation and characterization of phosphate solubilizing bacteria from the rhizospheric soil of Ponthenpuzha forest, Pathanamthitta (District), Kerala

Phosphorous is considered as a major parameter for crop yield. Its availability to plant is independent of its abundance. For the plants to utilize phosphorous, it is to be converted to absorbable form. Here, the part rendered by phosphate solubilizing bacteria is significant for it plays a crucial role in the formation of plant usable phosphate from organic forms. In the present work, an effort had been made to isolate and identify phosphate solubilising bacterial isolate from the rhizhospheric soils of various plants in Ponthenpuzha forest. One of the isolate from Cymbopogon citrates responded positively to Pikovskaya’s medium by producing a halo zone during in vitro culture. Colony features and 16S rRNA sequence analysis identified the isolate as Burkholderia sps. We have reported the presence of genus Burkholderia in the rhizospheric zone of Cymbopogon citratus. Further studies are warranted for species level identification of the isolate.

Hymenobacter Humicola sp. nov., Isolated from Soil in South Korea.

Two novel bacterial strains, designated as BT186T and BT505, were isolated from a soil sample collected in South Korea and characterized. Both strains were Gram-stain-negative, rod-shaped, aerobic, circular, convex, and had red-colored colonies. 16S rRNA sequence analysis indicated that strains BT186T and BT505 belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, kingdom Bacteria). Both strains were closely related to Hymenobacter norwichensis DSM 15439T (98.3% 16S rRNA gene similarity), Hymenobacter aquaticus JCM 31653T (96.8%), and Hymenobacter perfusus LMG26000T (96.5%). The strain BT186T was found to have the MK-7 as the major respiratory quinone. The major polar lipid of strain BT186T was identified to be phosphatidylethanolamine (PE). The major cellular fatty acid profiles of strain BT186T were C16:1 ω5c (24.3%), iso-C15:0 (20.3%) and summed feature 3 (C16:1 ω6c / C16:1 ω7c) (19.9%). Characterization based on polyphasic analysis indicated that strains BT186T and BT505 represent novel species of the genus Hymenobacter and the name Hymenobacter humicola sp. nov. is proposed. The type strain of Hymenobacter humicola is BT186T (= KCTC 72338T= NBRC 114968T).

Identification of Potential Bacteria on Several Lakes in East Java, Indonesia Based on 16S rRNA Sequence Analysis

Four bacterial isolates from Ranu Pani and Ranu Grati in east java had been revealed to be potentials to produce IAA (PIS isolate), phosphate solubilizer (GPS isolate), cellulose hydrolysis (PSS isolate) and, amylum hydrolysis (PAS), two dominant bacterial isolates from Rani Pani (PØD isolate) and Ranu Grati (GØD isolate) which were co-cultured with microalgae promoted microalgae growth, yet its taxonomical position has not been clearly known. The aim of this study was to identify those bacterial isolates using 16S rRNA barcode. This research conducted by gDNA isolation, the 16S rRNA sequence was amplified using 27F and 1492R primers. Reconstructed phylogenetic trees and genetic distance analysis showed that the isolate PIS and PSS identified as Bacillus cereus Group closely related to Bacillus paramycoides. PAS isolate identified as Bacillus subtilis Group closely related to Bacillus amyloliquefaciens, GPS isolate identified as novel species in genus Enterobacter, and two dominant isolates (PØD and GØD) identified as Enterobacter cloacae complex closely related to Enterobacter cloacae. The genomic approach and additional phenotypes-examination are required to clarify its taxonomical position.

Pseudomonas eucalypticola sp. nov., a producer of antifungal agents isolated from Eucalyptus dunnii leaves

Pseudomonas are ubiquitously occurring microorganisms and are known for their ability to produce antimicrobials. An endophytic bacterial strain NP-1 T, isolated from Eucalyptus dunnii leaves, exhibits antifungal properties against five tested phytopathogenic fungi. The strain is a Gram-negative rod-shaped bacterium containing a single polar flagellum. It is strictly aerobic, grows at 4–37 °C, 2–5% NaCl, and pH 3–7. The 16S rRNA sequence analysis showed that NP-1 T belongs to the Pseudomonas genus. Phylogenetic analysis based on four concatenated partial genes (16S rDNA, gyrB, rpoB and rpoD) and the phylogenomic tree indicated that NP-1 T belongs to Pseudomonas fluorescens lineage but is distinct from any known Pseudomonas species. The G + C mol % of NP-1 T genome is 63.96, and the differences between NP-1 T and related species are larger than 1. The digital DNA-DNA hybridization and tetranucleotide signatures are 23.8 and 0.97, which clearly separates strain NP-1 T from its closest neighbours, Pseudomonas coleopterorum and Pseudomonas rhizosphaerae. Its phenotypic and chemotaxonomic features confirmed its differentiation from related taxa. The results from this polyphasic approach support the classification of NP-1 T as a novel species of Pseudomonas, and the name of Pseudomonas eucalypticola is thus proposed for this strain, whose type is NP-1 T (= CCTCC M2018494T = JCM 33572 T).

Metagenomics and Culture Dependent Insights into the Distribution of Firmicutes across Two Different Sample Types Located in the Black Hills Region of South Dakota, USA

Firmicutes is almost a ubiquitous phylum. Several genera of this group, for instance, Geobacillus, are recognized for decomposing plant organic matter and for producing thermostable ligninolytic enzymes. Amplicon sequencing was used in this study to determine the prevalence and genetic diversity of the Firmicutes in two distinctly related environmental samples—South Dakota Landfill Compost (SDLC, 60 °C), and Sanford Underground Research Facility sediments (SURF, 45 °C). Although distinct microbial community compositions were observed, there was a dominance of Firmicutes in both the SDLC and SURF samples, followed by Proteobacteria. The abundant classes of bacteria in the SDLC site, within the phylum Firmicutes, were Bacilli (83.2%), and Clostridia (2.9%). In comparison, the sample from the SURF mine was dominated by the Clostridia (45.8%) and then Bacilli (20.1%). Within the class Bacilli, the SDLC sample had more diversity (a total of 11 genera with more than 1% operational taxonomic unit, OTU). On the other hand, SURF samples had just three genera, about 1% of the total population: Bacilli, Paenibacillus, and Solibacillus. With specific regard to Geobacillus, it was found to be present at a level of 0.07% and 2.5% in SURF and SDLC, respectively. Subsequently, culture isolations of endospore-forming Firmicutes members from these samples led to the isolation of a total of 117 isolates. According to colony morphologies, and identification based upon 16S rRNA and gyrB gene sequence analysis, we obtained 58 taxonomically distinct strains. Depending on the similarity indexes, a gyrB sequence comparison appeared more useful than 16S rRNA sequence analysis for inferring intra- and some intergeneric relationships between the isolates.