Efficacy and toxicity of hydrogen peroxide producing electrochemical bandages in a porcine explant biofilm model

Posted on 17 November 2022 by

Abstract

Aims

Effects of H₂O₂ producing electrochemical-bandages (e-bandages) on methicillin-resistant Staphylococcus aureus colonization and biofilm removal were assessed using a porcine explant biofilm model. Transport of H₂O₂ produced from the e-bandage into explant tissue and associated potential toxicity were evaluated.

Methods and Results

Viable prokaryotic cells from infected explants were quantified after 48 h treatment with e-bandages in three ex vivo S. aureus infection models: (1) reducing colonization, (2) removing young biofilms and (3) removing mature biofilms. H₂O₂ concentration-depth profiles in explants/biofilms were measured using microelectrodes. Reductions in eukaryotic cell viability of polarized and nonpolarized noninfected explants were compared. e-Bandages effectively reduced S. aureus colonization (p = 0.029) and reduced the viable prokaryotic cell concentrations of young biofilms (p = 0.029) with limited effects on mature biofilms (p > 0.1). H₂O₂ penetrated biofilms and explants and reduced eukaryotic cell viability by 32–44% compared to nonpolarized explants.

Conclusions

H₂O₂ producing e-bandages were most active when used to reduce colonization and remove young biofilms rather than to remove mature biofilms.

Significance and Impact of Study

The described e-bandages reduced S. aureus colonization and young S. aureus biofilms in a porcine explant wound model, supporting their further development as an antibiotic-free alternative for managing biofilm infections.

The potential of Bacillus subtilis and phosphorus in improving the growth of wheat under chromium stress

Posted on 17 November 2022 by

Abstract

Aim

Hexavalent chromium (Cr⁺⁶) is one of the most toxic heavy metals that have deteriorating effects on the growth and quality of the end product of wheat. Consequently, this research was designed to evaluate the role of Bacillus subtilis and phosphorus fertilizer on wheat facing Cr⁺⁶ stress.

Methods and Results

The soil was incubated with Bacillus subtilis and phosphorus fertilizer before sowing. The statistical analysis of the data showed that the co-application of B. subtilis and phosphorus yielded considerably more significant (p < 0.05) results compared with an individual application of the respective treatments. The co-treatment improved the morphological, physiological and biochemical parameters of plants compared with untreated controls. The increase in shoot length, root length, shoot fresh weight and root fresh weight was 38.17%, 29.31%, 47.89% and 45.85%, respectively, compared with untreated stress-facing plants. The application of B. subtilis and phosphorus enhanced osmolytes content (proline 39.98% and sugar 41.30%), relative water content and stability maintenance of proteins (86.65%) and cell membranes (66.66%). Furthermore, augmented production of antioxidants by 67.71% (superoxide dismutase), 95.39% (ascorbate peroxidase) and 60.88% (catalase), respectively, were observed in the Cr⁺⁶ – stressed plants after co-application of B. subtilis and phosphorus.

Conclusion

It was observed that the accumulation of Cr⁺⁶ was reduced by 54.24%, 59.19% and 90.26% in the shoot, root and wheat grains, respectively. Thus, the combined application of B. subtilis and phosphorus has the potential to reduce the heavy metal toxicity in crops.

Significance and Impact of the Study

This study explored the usefulness of Bacillus subtilis and phosphorus application on wheat in heavy metal stress. It is a step toward the combinatorial use of plant growth–promoting rhizobacteria with nutrients to improve the ecosystems' health.

Transcriptome reveals BCAAs biosynthesis pathway is influenced by lovastatin and can act as a potential control target in Phytophthora sojae

Posted on 17 November 2022 by

Abstract

Aims

Lovastatin has been indicated to impair growth and development of Phytophthora sojae. Therefore, this study was performed to understand the inhibitory mechanism of lovastatin and investigate the metabolic pathway potentially served as a new control target for this plant pathogen.

Methods and Results

Whole transcriptome analysis of lovastatin-treated P. sojae was performed by RNA-sequencing. The results revealed that 84 genes were upregulated and 58 were downregulated with more than fourfold changes under treatment. Kyoto Encyclopaedia of Genes and Genomes analysis indicated that the branched-chain amino acids (BCAAs) biosynthesis pathway was abundantly enriched. All enzymes in the BCAAs biosynthesis pathway were identified in the P. sojae genome. Moreover, the study found that the herbicide flumetsulam targeting acetohydroxyacid synthase (AHAS) of the BCAAs biosynthesis pathway could effectively inhibit mycelial growth of P. sojae.

Conclusions

Lovastatin treatment significantly influences the BCAAs biosynthesis pathway in P. sojae. Moreover, the herbicide flumetsulam targets AHAS and inhibits growth of P. sojae.

Significance and Impact of the Study

The present study revealed that BCAAs biosynthesis pathway was influenced by lovastatin treatment and its key enzyme AHAS was identified as a potential new control target, which provides clues for exploring more oomycetes to control plant diseases caused by P. sojae.

Dynamics of the fermentation quality and microbiotsa in Ephedra sinica treated native grass silage

Posted on 17 November 2022 by nShuai Du, nSihan You, nXiaowei Jiang, nYuyu Li, nYushan Jian

Abstract

Aims

This study aimed to evaluate the effects of Ephedra sinica on physicochemical characteristics and bacterial community of ensiled native grass by multiple physicochemical analyses combined with high-throughput sequencing.

Methods and Results

Treatments were a control treatment with no additive (CON), E. sinica was added at 1% (CEa1), 3% (CEa2), and 5% of the fresh materials (CEa3). Compared to the CON group, the dry matter and water-soluble carbohydrate contents were significantly (p < 0.05) decreased in the CEa1 group. Compared to the CON group, the pH was significantly (p < 0.05) decreased in E. sinica treated silages, and a higher lactic acid content was observed in E. sinica treated silages. At the genus level, the abundance of Enterococcus, Lactobacillus, Pediococcus, and Weissella were the predominant member in the CON, CEa1, CEa2, and CEa3 groups, respectively. The abundance of Lactobacillus was significantly (p < 0.05) increased in the CEa1 group and Pediococcus was significantly (p < 0.05) increased in the CEa2 group. According to the 16S rRNA gene-predicted functional profiles, the inoculation of E. sinica accelerated the carbohydrate metabolism.

Conclusions

In summary, the addition of E. sinica could improve the silage quality of native grass by regulating the bacterial community, and the addition of a 1% percentage of fresh materials exhibited the potential possibility of responding to get high-quality native grass silages.

Significance and Impact of the Study

The utilization of herbal additives on fermentation quality combined with 16S rRNA gene-predicted functional analyses will contribute to the direction of future research in improving silage quality.

Identification of spoilage microflora in draught beer using culture‐dependent methods

Posted on 17 November 2022 by nAlexander L. Jevons, nDavid E. Quainn

Abstract

Aims

To determine whether the culture-dependent spoilage microflora found in draught beer are influenced by beer style.

Methods and Results

Four beer styles—lager, ale, stout and cask ale – were sampled twice from five different public houses (accounts) in four different locations. The microbiological quality of the dispensed beers was determined by a culture-dependent method (‘forcing’), measuring the increase in turbidity after incubation at 30°C. The quality of draught beer varied from ‘excellent’ to ‘poor’ with cask beer samples having a higher Quality Index (90%) with keg ale the lowest (67.5%). With PCR amplified DNA (ITS1, ITS4, 16S rRNA primers) and blast identification of microflora, 386 colonies from agar plates were identified with 28 different micro-organisms from five genera of yeast and six of bacteria. Seven micro-organisms were found in all beer styles with Brettanomyces bruxellensis, B. anomalus and Acetobacter fabarum representing 53% of the identified micro-organisms. A subsequent, limited study using PALL multiplex PCR GeneDisc technology on forced samples (without selection on plates) suggests that draught beer microflora is qualitatively broader. It is noteworthy that the microflora of spoilt draught beer resembles that involved in the production of Belgian Lambic sour beers.

Conclusions

Draught beer was of variable quality. Culture-dependent analysis suggests that species of Brettanomyces and Acetobacter are core microflora with some micro-organisms being associated with beer style.

Significance and Impact of the Study

The microbiological quality of draught beer is important both commercially and to the consumer. Here, we report the core and diverse microflora found in different styles of draught beer using culture-dependent methods.

A 16S rRNA amplicon approach to the structural and functional diversity of bacterial communities associated with horse gram crop for drought mitigation and sustainable productivity

Posted on 17 November 2022 by nShirley Evangilene, nSivakumar Uthandin

Abstract

Aim

In this study, 16S rRNA amplicon sequencing analyses were performed to determine the diversity of the bacterial community present in the soil, rhizosphere region, root nodules and seeds of the horse gram plant.

Methods and Results

We observed the dominance of Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, Bacteroidetes, Planctomycetes and Gemmatimonadetes across all four domains of the horse gram plant. For community analyses, the significance of the alpha diversity was estimated using the Shannon index, Simpson index and Chao1 index, which revealed no significant difference among the samples. However, the estimation of the beta diversity indicated a significant difference among the samples, with p < 0.001 and R² = 1. A strong positive correlation was found between the rhizosphere and root nodule samples. Comparative genomics of the 16S rRNA gene showed that ammonium-oxidizing metabolism (amoA), nitrite-reducing metabolism (nirK) and nitrogen-fixing metabolism (nifH) were prominent mechanisms in all samples. The genes involved in the biosynthesis of amino acids, purine metabolism and nitrogen metabolism were identified as the key genes associated with the functional traits of microbial domains in horse gram.

Conclusion

The culturable microbes associated with horse gram can be used as a substitute for synthetic fertilizers to maintain soil fertility and ecological health in agricultural practices.

Significance and Impact of the study

Determining the survival strategies of bacterial communities that positively respond to multiple gate selection helps in understanding the structural diversity and functional traits primarily focused on the development of beneficial microbial consortium for promoting plant growth.

Leaf endophytic microbiomes of different almond cultivars grafted to the same rootstock

Posted on 17 November 2022 by nJ. Paola Saldierna Guzmán, nNicholas C. Dove, nStephen C. Hartn

Abstract

Aims

We compared the bacterial endophytic communities of three genetically different almond cultivars that were all grafted on the same type of rootstock, growing side by side within a commercial orchard.

Methods and Results

We examined the diversity of leaf bacterial endophytes using cultivation-independent techniques and assessed the relative abundance of bacterial families. Two of these three cultivars were dominated by Pseudomonadaceae, while the bacterial composition of the third cultivar consisted mainly of Streptococcaceae.

Conclusions

The experimental set up allowed us to analyse the impact of the shoot cultivar on endophytes, minimizing the influence of rootstock, biogeography, and cultivation status. Our data suggest that the shoot cultivar can shape the leaf endophytic community composition of almond trees.

Significance and Impact of the Study

Our results suggest that the shoot cultivar controls the composition of the foliar bacterial endophytic community of almonds. Overall, our results could provide a first step to develop strategies for a more sustainable almond agriculture.

Flexible multiplex PCR to detect SARS‐CoV‐2, coronavirus OC43 and influenza A virus in nasopharyngeal swab samples

Posted on 17 November 2022 by

Abstract

Introduction

Quantitative reverse transcription PCR (RT-qPCR) is the leading tool to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Given that it will almost certainly continue to coexist with other respiratory viruses in the coming years, our study aimed to design a multiplex PCR system not affected by supplier outages and with reduced cost compared to the existing commercially available kits.

Methods and results

In this study, combinations of four primers/probe sets were used to construct a flexible RT-qPCR assay which is capable of discriminating between SARS-CoV-2 and the seasonal human coronavirus HCoV-OC43, or even influenza A virus. Additionally, the human RPP30 gene was used as an internal control. To demonstrate the robustness of the assay, it was applied to a collection of 150 clinical samples. The results showed 100% sensitivity and specificity compared to the automatized system used at the hospital and were better when indeterminate samples were analysed.

Conclusions

This study provides an efficient method for the simultaneous detection of SARS-CoV-2, HCoV-OC43 and influenza A virus, and its efficacy has been tested on clinical samples showing outstanding results.

Significance and impact of the study

The multiplex RT-qPCR design offers an accessible and economical alternative to commercial detection kits for hospitals and laboratories with limited economic resources or facing situations of supply shortage.

Ultrasound‐assisted facile synthesis of Boron‐Heck‐coupled sclareol analogues as potential antibacterial agents against Staphylococcus aureus

Posted on 17 November 2022 by

Abstract

Aim

To evaluate the antimicrobial capability of sclareol and its derivatives against Staphylococcus aureus and its Methicillin-resistant strain (MRSA).

Methods and Results.

A new series of Boron-Heck-coupled sclareol analogues were prepared by structural modifications at the C-15 terminal double bond of sclareol using ultrasonication. The structural modifications were designed to keep the stereochemistry of all the five chiral centres of sclareol intact. A two-step reaction scheme consisting of Boron-Heck coupling of sclareol followed by Wittig reaction was carried out to produce novel sclareol congeners for antimicrobial evaluation. Three compounds SAJ-1, SAJ-2 and SB-11 exhibited strong antibacterial activity against S. aureus and Methicillin-resistant strain (MRSA) with MIC values between 3 and 11 μM. Among all the screened compounds, SAJ-1 and SAJ-2 showed the best antibiofilm profiles against both strains. Moreover, SAJ-1 and SAJ-2 acted synergistically with streptomycin against S. aureus while creating varying outcomes in combination with ciprofloxacin, penicillin and ampicillin. SAJ-1 also acted synergistically with ampicillin against S. aureus, while SB-11 showed synergism with ciprofloxacin against both pathogens. Moreover, SAJ-1 and SAJ-2 also inhibited staphyloxanthin production in S. aureus and MRSA and induced postantibiotic effects against both pathogens.

Conclusions

It can be inferred that SAJ-1, SAJ-2 and SB-11 may act as potential chemical entities for the development of antibacterial substances. The study revealed that SAJ-1 and SAJ-2 are the most suitable sclareol analogues for further studies towards the development of antibacterial substances.

Significance and Impact of the Study

SAJ-1, SAJ-2 and SB-11 show promising antibacterial properties against Staphylococcus aureus. Efforts should be made and more research should be done utilizing in vivo models to determine their efficacy as antibiotics.

Effects of Bacillus subtilis natto JLCC513 on gut microbiota and intestinal barrier function in obese rats

Posted on 17 November 2022 by

Abstract

Aims

This study aimed to investigate the effects of Bacillus subtilis natto JLCC513 (JLCC513) on gut microbiota, inflammation and intestinal barrier function in high-fat-diet (HFD) rats.

Methods and Results

Sprague–Dawley (SD) rats were fed HFD for 16 weeks, and treated with JLCC513 in 9th week. The oral administration of JLCC513 decreased body weight and reduced the inflammation level in HFD rats. Pathologically, JLCC513 prevented the detachment of ileal villus and increased the villus height in rats. Mechanistically, western blot analysis showed that the protein levels of tight junction (TJ) proteins involved in intestinal barrier function, including zonula occludens-1 (ZO-1), occludin and claudin-1, were increased after JLCC513 treatment. Meanwhile, JLCC513 treatment also decreased the protein levels of toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) and NOD-like receptor protein 3 (NLRP3), indicating inhibition of the TLR4/NF-κB/NLRP3 pathway. Furthermore, faecal analysis showed that JLCC513 increased the abundance of Lactobacillus and Oscillospira and the ratio of Firmicutes/Bacteroidetes (F/B), and decreased the levels of Blautia and C_Clostridium.

Conclusions

JLCC513 alleviated intestinal barrier dysfunction by inhibiting TLR4/NF-κB/NLRP3 pathway and regulating gut microbiota disorders.

Significance and Impact of Study

Our study might provide new treatment strategies for obesity and metabolic diseases.