Halonatronomonas betaini gen. nov., sp. nov., a haloalkaliphilic isolate from soda lake capable of betaine degradation and proposal of Halarsenatibacteraceae fam. nov. and Halothermotrichaceae fam. nov. within the order Halanaerobiales

A search for the organisms responsible for anaerobic betaine degradation in soda lakes resulted in isolation of a novel bacterial strain, designated Z-7014^T. The cells were Gram-stain-negative, non-endospore-forming rods. Growth occurred at 8–52 °C (optimum 40–45 °C), pH 7.1–10.1 (optimum pH 8.1–8.8) and 1.0–3.5 M Na⁺ (optimum 1.8 M), i.e. it can be regarded as a haloalkaliphile. The strain utilized a limited range of substrates, mostly peptonaceous but not amino acids, and was able to degrade betaine. Growth on betaine occurred only in the presence of peptonaceous substances which could not be replaced by vitamins. The G + C content of the genomic DNA of strain Z-7014^T was 36.1 mol%. The major cellular fatty acids (>5% of the total) were C_16:0 DMA, C_{18: 0} DMA, C_16:1ω8, C_16:0, C_18:1 DMA, C_16:1 DMA, C_18:1ω9, and C_18:0. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain Z-7014^T formed a distinct evolutionary lineage in the order Halanaerobiales with the highest similarity to Halarsenitibacter silvermanii SLAS-1^T (83.6%), Halothermothrix orenii H168^T (85.6%), and Halocella cellulosilytica DSM 7362^T (85.6%). AAI and POCP values between strain Z-7014^T and type strains of the order Halanaerobiales were 51.7–57.8%, and 33.8–58.3%, respectively. Based on polyphasic results including phylogenomic data, the novel strain could be distinguished from other genera, which suggests that strain Z-7014^T represents a novel species of a new genus, for which the name Halonatronomonas betaini gen. nov., sp. nov. is proposed. The type strain is Z-7014^T (=KCTC 25237^T = VKM B-3506^T). On the basis of phylogenomic data, it is also proposed to evolve two novel families Halarsenitibacteraceae fam. nov. and Halothermotrichaceae fam. nov. within the current order Halanaerobiales.     

Halomonas alkalisoli sp. nov., a novel haloalkalophilic species from saline-alkaline soil,and reclassification of Halomonas daqingensis Wu et al. 2008 as a later heterotypic synonym of Halomonas desiderata Berendes et al. 1996

Two Gram-stain-negative, strictly aerobic, moderately halophilic, non-spore-forming and rod-shaped bacteria, designated M5N1S17^T and M5N1S15, were isolated from saline soil in Baotou, China. A phylogenetic analysis based on 16S rRNA gene sequences showed that the two strains clustered closely with Halomonas montanilacus PYC7W^T and shared 99.1 and 99.3% sequence similarities, respectively. The average nucleotide identity based on BLAST (ANIb) and MUMmer (ANIm) values of the two strains with each other were 95.5% and 96.7%, respectively, while the ANIb and ANIm values between the two strains and 15 closer Halomonas species were 74.8–91.3% and 84.1–92.6%, respectively. The major polar lipids of M5N1S17^T are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, and an unidentified phospholipid. The major polar lipids of M5N1S15 are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, two unidentified phospholipids, and an unidentified lipid. The predominant ubiquinone in the two strains is Q-9. The major fatty acids of the two strains are C_18:1 ω6c and/or C_18:1 ω7c, C_16:0, and C_16:1 ω7c and/or C_16:1 ω6c. Based on phylogenetic, phenotypic, and physiological results, strains M5N1S17^T and M5N1S15 should be identified as a novel species of the genus Halomonas, for which Halomonas alkalisoli sp. nov. is proposed. The type strain is M5N1S17^T (= CGMCC 1.19023^T = KCTC 92130^T). The phylogenetic trees showed that Halomonas daqingensis CGMCC 1.6443^T clustered tightly with Halomonas desiderata FB2^T, and the two strains shared >98.0% of ANI values with each other. Therefore, we propose the reclassification of H. daqingensis Wu et al. 2008 as a later heterotypic synonym of H. desiderata Berendes et al. 1996.     

Botrydial confers Botrytis cinerea the ability to antagonize soil and phyllospheric bacteria

The role of the sesquiterpene botrydial in the interaction of the phytopathogenic fungus Botrytis cinerea and plant-associated bacteria was analyzed. From a collection of soil and phyllospheric bacteria, nine strains sensitive to growth-inhibition by B. cinerea were identified. B. cinerea mutants unable to produce botrydial caused no bacterial inhibition, thus demonstrating the inhibitory role of botrydial. A taxonomic analysis showed that these bacteria corresponded to different Bacillus species (six strains), Pseudomonas yamanorum (two strains) and Erwinia aphidicola (one strain). Inoculation of WT and botrydial non-producing mutants of B. cinerea along with Bacillus amyloliquefaciens strain MEP₂18 in soil demonstrated that both microorganisms exert reciprocal inhibitory effects; the inhibition caused by B. cinerea being dependent on botrydial production. Moreover, botrydial production was modulated by the presence of B. amyloliquefaciens MEP₂18 in confrontation assays in vitro. Purified botrydial in turn, inhibited growth of Bacillus strains in vitro and cyclic lipopeptide (surfactin) production by B. amyloliquefaciens MEP₂18. As a whole, results demonstrate that botrydial confers B. cinerea the ability to inhibit potential biocontrol bacteria of the genus Bacillus. We propose that resistance to botrydial could be used as an additional criterion for the selection of biocontrol agents of plant diseases caused by B. cinerea.     

Streptomyces poriferorum sp. nov., a novel marine sponge-derived Actinobacteria species expressing anti-MRSA activity

Marine sponges represent a rich source of uncharacterized microbial diversity, and many are host to microorganisms that produce biologically active specialized metabolites. Here, a polyphasic approach was used to characterize two Actinobacteria strains, P01-B04^T and P01-F02, that were isolated from the marine sponges Geodia barretti (Bowerbank, 1858) and Antho dichotoma (Esper, 1794), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains P01-B04^T and P01-F02 are closely related to Streptomyces beijiangensis DSM 41794^T, Streptomyces laculatispora NRRL B-24909^T, and Streptomyces brevispora NRRL B-24910^T. The two strains showed nearly identical 16S rRNA gene sequences (99.93%), and the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values were 99.96% and 99.6%, respectively, suggesting that these strains are affiliated with the same species. Chemotaxonomic and culture characteristics of both strains were also consistent with the genus Streptomyces, while phenotypic properties, genome-based comparisons, and phylogenomic analyses distinguished strains P01-B04^T and P01-F02 from their closest phylogenetic relatives. In silico analysis predicted that the 8.9 Mb genome of P01-B04^T contains at least 41 biosynthetic gene clusters (BGCs) encoding secondary metabolites, indicating that this strain could express diverse bioactive metabolites; in support of this prediction, this strain expressed antibacterial activity against Gram-positive bacteria including a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) EAMC30. Based on these results, the marine sponge-associated isolates represent a novel species of the genus Streptomyces, for which the name Streptomyces poriferorum sp. nov. is proposed, with P01-B04^T (=DSM 111306^T = CCM 9048^T) as the type strain.     

Characterization of two novel pentose-fermenting and GABA-producing species: Levilactobacillus tujiorum sp. nov. and Secundilactobacillus angelensis sp. nov. Isolated from a solid-state fermented zha-chili

Lactobacilli are dominant in zha-chili. This study provides a taxonomic characterization of five bacterial strains isolated from zha-chili in China. The cells were Gram-positive, facultative anaerobic, non-spore-forming, flagella-free, catalase-negative, heterofermentative, pentose-fermenting, and gamma-aminobutyric acid (GABA)-producing rods. For HBUAS51241^T, HBUAS51329, and HBUAS51416, C_16:0, C_18:1 ω9c and C_19:0 iso were the predominant cellular fatty acids; diphosphatidylglycerol (DPG), phosphatidylglycerol (DP), glycolipids (GL), and glycolipids (AL) were the major phospholipids. While for HBUAS51383^T and HBUAS58055, C_16:0, C_18:1 ω9c, C_19:0 cyclo ω8c were the predominant cellular fatty acids; DPG, DP, GL, and AL were the major phospholipids. Strains HBUAS51241^T, HBUAS51329, and HBUAS51416 showed 98.1–99.1% 16S rRNA gene sequence similarity, 80.2–81.4% ANI, 87.7–90.0% AAI, and 23.8–32.8% digital DDH to their closest related type strains Levilactobacillus hammesii DSM 16381^T, Levilactobacillus parabrevis ATCC 53295^T, and Levilactobacillus fuyuanensis 244-4^T. Strains HBUAS51383^T and HBUAS58055 showed 98.7–99.5% 16S rRNA gene sequence similarity, 75.4–81.4% ANI, 75.5–89.1% AAI, and 19.7–24.0% digital DDH to their closest related type strains Secundilactobacillus silagincola IWT5^T, Secundilactobacillus silagei JCM 19001^T, Secundilactobacillus pentosiphilus IWT25^T, Secundilactobacillus mixtipabuli IWT30^T, Secundilactobacillus odoratitofui DSM 19909^T, and Secundilactobacillus similis DSM 23365^T. The central carbon metabolism pathways for the five strains were summarizeded. Based on the phenotypic, chemotaxonomic, and genomic data, we propose two novel species Levilactobacillus tujiorum sp. nov. whose type strain is HBUAS51241^T (=GDMCC 1.3022^T = JCM 35241^T), and Secundilactobacillus angelensis sp. nov. whose type strain is HBUAS51383^T (=GDMCC 1.3021^T = JCM 35209^T).     

Weizmannia acidilactici sp. nov., a lactic acid producing bacterium isolated from soils

The strains designed PP-18^T, JC-4 and JC-7 isolated from soils, were Gram-stain-positive rods, facultative anaerobe, endospore-forming bacteria. The strains produced l-lactic acid from glucose. They showed positive for catalase but negative for oxidase, nitrate reduction and arginine hydrolysis. Strains P-18^T, JC-4 and JC-7 were closely related to Weizmannia coagulans LMG 6326^T (97.27–97.64%) and W. acidiproducens KCTC 13078^T (96.46–96.74%) based on 16S rRNA gene sequence similarity, respectively. They contained meso-diaminopimelic acid in cell wall peptidoglycan and had seven isoprene units (MK-7) as the predominant menaquinone. The major cellular fatty acids of strain PP-18^T were iso-C_15:0, anteiso-C_17:0, iso-C_16:0 and anteiso-C_15:0. The ANIb and ANIm values among the genomes of strains PP-18^T, JC-4 and JC-7 are above 99.4% while their ANIb and ANIm values among them and W. coagulans LMG 6326^T and W. acidiproducens KCTC 13078^T were ranged from 76.61 to 79.59%. These 3 strains showed the digital DNA-DNA hybridization (dDDH) values of 20.7–23.6% when compared with W. coagulans LMG 6326^T and W. acidiproducens DSM 23148^T. The DNA G + C contents of strains PP-18^T, JC-4 and JC-7 were 45.82%, 45.86% and 45.86%, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphoglycolipids. The results of phenotypic and chemotaxonomic characteristics and whole-genome analysis indicated that the strains PP-18^T, JC-4 and JC-7 should be represented as a novel species within the genus Weizmannia for which the name Weizmannia acidilactici sp. nov. is proposed. The type strain is PP-18^T (=KCTC 33974^T = NBRC 113028^T = TISTR 2515^T).     

Pseudomonas petrae sp. nov. isolated from regolith samples in Antarctica

A polyphasic taxonomic approach was used to characterize the four strains P2653^T, P2652, P2498, and P2647, isolated from Antarctic regolith samples. Initial genotype screening performed by PCR fingerprinting based on repetitive sequences showed that the isolates studied formed a coherent cluster separated from the other Pseudomonas species. Identification results based on 16S rRNA gene sequences showed the highest sequence similarity with Pseudomonas graminis (99.7%), which was confirmed by multilocus sequence analysis using the rpoB, rpoD, and gyrB genes. Genome sequence comparison of P2653^T with the most related P. graminis type strain DSM 11363^T revealed an average nucleotide identity of 92.1% and a digital DNA-DNA hybridization value of 46.6%. The major fatty acids for all Antarctic strains were C_16:0, Summed Feature 3 (C_16:1 ω7c/C_16:1 ω6c) and Summed Feature 8 (C_18:1 ω7c/C_18:1 ω6c). The predominant respiratory quinone was Q-9, and the major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol. The regolith strains could be differentiated from related species by the absence of arginine dihydrolase, ornithine and lysine decarboxylase and by negative tyrosine hydrolysis. The results of this polyphasic study allowed the genotypic and phenotypic differentiation of four analysed strains from the closest related species, which confirmed that the strains represent a novel species within the genus Pseudomonas, for which the name Pseudomonas petrae sp. nov. is proposed with P2653^T (CCM 8850^T = DSM 112068^T = LMG 30619^T) as the type strain.     

Magnetospirillum sulfuroxidans sp. nov., capable of sulfur-dependent lithoautotrophy and a taxonomic reevaluation of the order Rhodospirillales

A spiral-shaped, highly motile bacterium was isolated from freshwater sulfidic sediment. Strain J10^T is a facultative autotroph utilizing sulfide, thiosulfate, and sulfur as the electron donors in microoxic conditions. Despite high 16S rRNA gene sequence sequence identity to Magnetospirillum gryphiswaldense MSR-1 ^T (99.6 %), digital DNA-DNA hybridisation homology and average nucleotide identity between the two strains was of the different species level (25 % and 83 %, respectively). Strain J10^T is not magnetotactic. The DNA G + C content of strain J10^T is 61.9 %. The predominant phospholipid ester-linked fatty acids are C18:1ω7, C16:1ω7, and C16:0. Strain J10^T (=DSM 23205 ^T = VKM B-3486 ^T) is the first strain of the genus Magnetospirillum showing lithoautotrophic growth and is proposed here as a novel species, Magnetospirillum sulfuroxidans sp. nov. In addition, we propose to establish a framework for distinguishing genera and families within the order Rhodospirillales based on phylogenomic analysis using the threshold values for average amino acid identity at ̴ 72 % for genera and ̴ 60 % for families. According to this, we propose to divide the existing genus Magnetospirillum into three genera: Magnetospirillum, Paramagnetospirillum, and Phaeospirillum, constituting a separate family Magnetospirillaceae fam. nov. in the order Rhodospirillales. Furthermore, phylogenomic data suggest that this order should accomodate six more new family level groups including Magnetospiraceae fam. nov., Magnetovibrionaceae fam. nov., Dongiaceae fam. nov., Niveispirillaceae fam. nov., Fodinicurvataceae fam. nov., and Oceanibaculaceae fam. nov.     

Description of Aestuariivivens marinum sp. nov., Aestuariivivens sediminis sp. nov. and Aestuariivivens sediminicola sp. nov., three new species isolated from the upper layer of tidal flat sediment

Nine bacterial strains designated MT3-5-12^T, MT3-5-27, MTV1-9, S-DT1-15^T, S-DT1-34, MTV5-3^T, MTV4-17, MTV5-12 and MTV5-13 were isolated from the upper layer (1–5 cm in depth) of tidal flat sediment in Quanzhou Bay, China. The 16S rRNA gene of these strains shared maximum sequence similarities with Aestuariivivens insulae KCTC 42350^T of 94.9–97.1%. Phylogenetic analyses based on 16S rRNA gene sequences and 120 conserved concatenated proteins placed these strains in three novel phylogenetic clades affiliated to the genus Aestuariivivens of the family Flavobacteriaceae. Strains MT3-5-12^T, MT3-5-27 and MTV1-9 were phylogenetically close to A. insulae KCTC 42350^T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strains MT3-5-12^Tand MTV1-9 and A. insulae KCTC 42350^T were estimated to be 78.5-78.7% and 22.5%, respectively. Strains S-DT1-15^T and S-DT1-34 formed a distinctly separated clade from A. insulae KCTC 42350^T. The ANI and dDDH values between strains S-DT1-15^T and S-DT1-34 and A. insulae KCTC 42350^T were 76.3–76.4% and 20.4–20.5%, respectively. The other four strains MTV5-3^T, MTV4-17, MTV5-12 and MTV5-13, formed a third novel clade, distinctly separated from A. insulae KCTC 42350^T. The ANI and dDDH values between strains MTV5-3^T and MTV4-17 and A. insulae KCTC 42350^T were 74.7% and 19.1–19.2%, respectively. The phylogenetic analyses and whole genomic comparisons, combined with phenotypic and chemotaxonomic features, strongly supported the nine strains could be classified as three novel species within the genus Aestuariivivens, for which the names Aestuariivivens marinum sp. nov. MT3-5-12^T, Aestuariivivens sediminis sp. nov. S-DT1-15^T, and Aestuariivivens sediminicola sp. nov. MTV5-3^T are proposed.     

Biosynthesis of silver nanoparticles using Malva parviflora and their antifungal activity

Cheeseweed mallow (Malva parviflora L.) was used to biosynthesize silver nanoparticles. The biosynthesized silver nanoparticles were classified by UV–vis Spectroscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). The shape and size distribution were visualized by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Zeta potential analysis. The chemical composition of M. parviflora leaf extract was identified by Gas Chromatography and Mass Spectroscopy (GC/MS). Finally, in vitro antifungal assay was done to assess the potential of biosynthesized silver nanoparticles and crude leaf extract of M. parviflora for inhibiting the mycelial growth of phytopathogenic fungi. The UV–vis analysis manifests the formation of silver nanoparticles. FTIR analysis established that chemicals of the leaf extract stabilized the biosynthesized silver nanoparticles by binding with the free silver ions. The TEM, FE-SEM and zeta potential analyzer confirmed that the biosynthesized silver nanoparticles were mostly spherical with an average diameter of 50.6 nm. The biosynthesized silver nanoparticles and leaf extract of M. parviflora effectively mitigate the mycelial growth of Helminthosporium rostratum, Fusarium solani, Fusarium oxysporum, and Alternaria alternata. The maximum reduction in mycelial growth by biosynthesized nanoparticles was observed against H. rostratum (88.6%). Whereas, the leaf extract of M. parviflora was most effective against F. solani (65.3%). Thus, the biosynthesis of nanoparticle assisted by M. parviflora is a feasible and eco-friendly method for the synthesis of silver nanoparticles. Further the silver nanoparticles and leaf extract of M. parviflora could be explored for the development of the fungicide.     

Mangiferin: A promising natural xanthone from Mangifera indica for the control of acyclovir – resistant herpes simplex virus 1 infection

Mangiferin is found in many plant species as the mango tree (Mangifera indica) with ethnopharmacological applications and scientific evidence. The emergence of resistant herpes simplex virus (HSV) strains to Acyclovir (ACV) has encouraged the search for new drugs. We investigated the in vitro and in vivo activity of mangiferin obtained from M. indica against ACV-resistant HSV-1 (AR-29) and sensitive (KOS) strains. The in vitro activity was performed under varying treatment protocols. The substance showed a CC₅₀ > 500 μg/mL and IC₅₀ of 2.9 μg/mL and 3.5 μg/mL, respectively, for the AR-29 and KOS strains. The in vivo activity was performed in Balb/c mice treated with 0.7% topical mangiferin formulation. This formulation inhibited most effectively the AR-29 strain, attenuated the lesions, postponed their appearance or enhanced healing, in comparison to control group. We demonstrated the potentiality of mangiferin from M. indica to control HSV replication with emphasis to ACV-resistant infection.     

Rhodopirellula aestuarii sp. nov., a novel member of the genus Rhodopirellula isolated from brackish sediments collected in the Tagus River estuary,Portugal

Bacteria within the phylum Planctomycetota are biologically relevant due to unique characteristics among prokaryotes. Members of the genus Rhodopirellula can be abundant in marine habitats, however, only six species are currently validly described. In this study, we expand the explored genus diversity by formally describing a novel species. The pink-coloured strain ICT_H3.1^T was isolated from brackish sediments collected in the Tagus estuary (Portugal) and a 16S rRNA gene sequence-based analysis placed this strain into the genus Rhodopirellula (family Pirellulaceae). The closest type strain is Rhodopirellula rubra LF2^T, suggested by a similarity of 98.4% of the 16S rRNA gene sequence. Strain ICT_H3.1^T is heterotrophic, aerobic and able to grow under microaerobic conditions. The strain grows between 15 and 37 °C, over a range of pH 6.5 to 11.0 and from 1 to 8% (w/v) NaCl. Several nitrogen and carbon sources were utilized by the novel isolate. Cells have an elongated pear-shape with 2.0 ± 0.3 × 0.9 ± 0.2 µm in size. Cells of strain ICT_H3.1^T cluster in rosettes through a holdfast structure and divide by budding. Younger cells are motile. Ultrathin cell sections show cytoplasmic membrane invaginations and polar fimbriae. The genome size is 9,072,081 base pairs with a DNA G + C content of 56.1 mol%. Genomic, physiological and morphological comparison of strain ICT_H3.1^T with its relatives suggest that it belongs to a novel species within the genus Rhodopirellula. Hence, we propose the name Rhodopirellula aestuarii sp. nov., represented by ICT_H3.1^T (=CECT30431^T = LMG32464^T) as the type strain of this novel species.16S rRNA gene accession number: GenBank = OK001858.Genome accession number: The Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession JAMQBK000000000. The version described in this paper is version JAMQBK010000000.     

Govania unica gen. nov., sp. nov., a rare biosphere bacterium that represents a novel family in the class Alphaproteobacteria

Strain LMG 31809 ^T was isolated from a top soil sample of a temperate, mixed deciduous forest in Belgium. Comparison of its 16S rRNA gene sequence with that of type strains of bacteria with validly published names positioned it in the class Alphaproteobacteria and highlighted a major evolutionary divergence from its near neighbor species which represented species of the orders Emcibacterales and Sphingomonadales. 16S rRNA amplicon sequencing of the same soil sample revealed a highly diverse community in which Acidobacteria and Alphaproteobacteria predominated, but failed to yield amplicon sequence variants highly similar to that of strain LMG 31809 ^T. There were no metagenome assembled genomes that corresponded to the same species and a comprehensive analysis of public 16S rRNA amplicon sequencing data sets demonstrated that strain LMG 31809 ^T represents a rare biosphere bacterium that occurs at very low abundances in multiple soil and water-related ecosystems. The genome analysis suggested that this strain is a strictly aerobic heterotroph that is asaccharolytic and uses organic acids and possibly aromatic compounds as growth substrates. We propose to classify LMG 31809 ^T as a novel species within a novel genus, Govania unica gen. nov., sp. nov, within the novel family Govaniaceae of the class Alphaproteobacteria. Its type strain is LMG 31809 ^T (=CECT 30155 ^T). The whole-genome sequence of strain LMG 31809 ^T has a size of 3.21 Mbp. The G + C content is 58.99 mol%. The 16S rRNA gene and whole-genome sequences of strain LMG 31809 ^T are publicly available under accession numbers OQ161091 and JANWOI000000000, respectively.     

Reprogramming Escherichia coli pyruvate-forming reaction towards chorismate derivatives production

Microbial metabolic pathway engineering is a potent strategy used worldwide to produce aromatic compounds. We drastically rewired the primary metabolic pathway of Escherichia coli to produce aromatics and their derivatives. The metabolic pathway of E. coli was compartmentalized into the production and energy modules. We focused on the pyruvate-forming reaction in the biosynthesis pathway of some compounds as the reaction connecting those modules. E. coli strains were engineered to show no growth unless pyruvate was synthesized along with the compounds of interest production. Production of salicylate and maleate was demonstrated to confirm our strategy's versatility. In maleate production, the production, yield against the theoretical yield, and production rate reached 12.0 g L⁻¹, 67%, and up to fourfold compared to that in previous reports, respectively; these are the highest values of maleate production in microbes to our knowledge. The results reveal that our strategy strongly promotes the production of aromatics and their derivatives.     

In vitro susceptibility of human Blastocystis subtypes to simeprevir

Introduction and aimBlastocystis is a common enteric parasite, having a worldwide distribution. Many antimicrobial agents are effective against it, yet side effects and drug resistance have been reported. Thus, ongoing trials are being conducted for exploring anti-Blastocystis alternatives. Proteases are attractive anti-protozoal drug targets, having documented roles in Blastocystis. Serine proteases are present in both hepatitis C virus and Blastocystis. Since drug repositioning is quite trendy, the in vitro efficacy of simeprevir (SMV), an anti-hepatitis serine protease inhibitor, against Blastocystis was investigated in the current study.MethodsStool samples were collected from patients, Alexandria, Egypt. Concentrated stools were screened using direct smears, trichrome, and modified Ziehl-Neelsen stains to exclude parasitic co-infections. Positive stool isolates were cultivated, molecularly subtyped for assessing the efficacy of three SMV doses (100,150, and 200 μg/ml) along 72 hours (h), on the most common subtype, through monitoring parasite growth, viability, re-culture, and also via ultrastructure verification. The most efficient dose and duration were later tested on other subtypes.ResultsResults revealed that Blastocystis was detected in 54.17% of examined samples. Molecularly, ST3 predominated (62%), followed by ST1 (8.6%) and ST2 (3.4%). Ascending concentrations of SMV progressively inhibited growth, viability, and re-culture of treated Blastocystis, with a non-statistically significant difference when compared to the therapeutic control metronidazole (MTZ). The most efficient dose and duration against ST3 was 150 µg/ml for 72 h. This dose inhibited the growth of ST3, ST1, and ST2 with percentages of 95.19%, 94.83%, and 94.74%, successively and viability with percentages of 98.30%, 98.09%, and 97.96%, successively. This dose abolished Blastocystis upon re-culturing. Ultra-structurally, SMV induced rupture of Blastocystis cell membrane leading to necrotic death, versus the reported apoptotic death caused by MTZ. In conclusion, 150 µg/ml SMV for 72 h proved its efficacy against ST1, ST2, and ST3 Blastocystis, thus sparing the need for pre-treatment molecular subtyping in developing countries.     

Antifungal potential,chemical composition of Chlorella vulgaris and SEM analysis of morphological changes in Fusarium oxysporum

In pursuit of an environmentally benign fungicide alternative, the current study explored the antifungal activity of Chlorella vulgaris extracts against six plant pathogenic fungi (in vitro). The well diffusion agar method was used to investigate the growth inhibition of Fusarium oxysporum, Fusarium sp., Fusarium solani, A. flavus, A. niger, and A. alternata using the three C. vulgaris extracts viz. methanol (CvME), acetone (CvAE), and diethyl ether (CvDE). Different concentrations of CvDE were also investigated against F. oxysporum. The morphological modifications in F. oxysporum treated with CvDE (5 mg/kg) were studied using SEM and the chemical composition of CvDE was also determined by GC–MS analysis. All extracts, with the exception of A. alternata, were found to be effective in inhibiting the growth of plant pathogenic fungi. The CvDE extract, followed by CvME and CvAE, was found to be efficient against tested fungi. The CvDE was most effective against F. oxysporum with a 73.3% growth inhibition. The effects of various CvDE concentrations on F. oxysporum were found to be dosage dependent. The SEM micrograph revealed that CvDE-treated F. oxysporum had substantially less conidia than the control. The CvDE treatment damaged the mycelial structure as well. Major chemical components detected in CvDE were Heptaldehyde (15.7%), Octadecenoic acid, methyl ester (12.6%), Hexadecanoic acid (12%), 3-Decyn-2-Ol (10.98%), (E)-3,7,11,15-tetramethylhexadec-2-ene (9.76%), heptadecane-1,2,3,4,5-pentol (8.7%), Docosane, 4-methyl (7.28%).