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Microbiological Research
Urban & Fischer Verlag DmbH & Co.
Microbiological Research

Urban & Fischer Verlag DmbH & Co.

0944-5013

Microbiological Research/Journal Microbiological ResearchSCIEIAHCI
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    Application of pseudovirus system in the development of vaccine, antiviral-drugs, and neutralizing antibodies

    Xiang Q.Li L.Wu J.Tian M....
    10页
    查看更多>>摘要:? 2022Pseudoviruses are viral particles coated with a heterologous envelope protein, which mediates the entry of pseudoviruses as efficiently as that of the live viruses possessing high pathogenicity and infectivity. Due to the deletion of the envelope protein gene and the absence of pathogenic genes, pseudoviruses have no autonomous replication ability and can infect host cells for only a single cycle. In addition, pseudoviruses have the desired characteristics of high safety, strong operability, and can be easily used to perform rapid throughput detection. Therefore, pseudoviruses are widely employed in the mechanistic investigation of viral infection, the screening and evaluation of monoclonal antibodies and antiviral drugs, and the detection of neutralizing antibody titers in serum after vaccination. In this review, we will discuss the construction of pseudoviruses based on different packaging systems, their current applications especially in the research of SARS-CoV-2, limitations, and further directions.

    Antibacterial efficacies and time-kill kinetics of indigenous Ghanaian spice extracts against Listeria monocytogenes and some other food-borne pathogenic bacteria

    Tano-Debrah K.Xedzro C.Nakano H.
    10页
    查看更多>>摘要:? 2022 Elsevier GmbHIncrease in food-borne outbreaks has become public health concern worldwide. Exploitation of the antimicrobial properties of dietary spices has become important pharmaceutical tool for controlling food-borne pathogens. This study aimed at evaluating the antibacterial potentials of Ghanaian spices against Listeria monocytogenes and other prevalent food-borne pathogens. In preliminary studies, Listeria was isolated from some food samples. The overall prevalence of Listeria spp. was 23% (13/56). Of the 56 samples examined, 7% showed pathogenic potential for L. monocytogenes. Different solvent extracts of thirteen spices namely Calabash nutmeg, West African black pepper, Aidan, Grains of paradise, Negro pepper, Aniseed, African locust bean, Cinnamon, Black pepper, Clove, Cayenne, Basil, and Rauvolfia were tested for their potentials to inhibit clinical and isolated strains of L. monocytogenes using qualitative and quantitative antimicrobial assay methods. Only clove and negro pepper among the thirteen different solvent extracts showed bacteriostatic and bactericidal activity against L. monocytogenes indicated by minimum inhibitory concentrations ranging from 0.05% to 0.4% and minimum bactericidal concentrations ranging from 0.1% to > 0.4% under experimental conditions. Time-kill study demonstrated listericidal activity of ethanolic clove and negro pepper extracts indicated by absolute mortality of more than 3 log units at 2x MIC and 4x MIC. GC-MS analysis revealed three and eight major chemical components present in clove and negro pepper respectively. Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus cereus, and B. subtilis also showed satisfactory susceptibilities to ethanolic extracts with MIC ranging from 0.025% to > 0.8%. In general, negro pepper showed broad activity eliciting inhibitory effects against all the tested pathogens. The findings suggest that clove and negro pepper may be promising antibacterial candidates for the decontamination and control bacterial pathogens in food and food supply chain.

    Plant organ and sampling time point determine the taxonomic structure of microbial communities associated to apple plants in the orchard environment

    Bozza E.Sicher C.Pertot I.Perazzolli M....
    12页
    查看更多>>摘要:? 2022 Elsevier GmbHPlant-associated microbial communities interact with their host and are important components of the biodiversity of natural and agro-ecosystems. Scarce knowledge is available on the establishment of plant microbiota in perennial woody plants. In this work the variability in bacterial and fungal communities in aboveground organs was analysed in leaves, bark, flowers and fruits on three apple cultivars (Gala, Fuji and Golden), in order to understand changes of the microbiota community structure from orchard planting to the first year of fruit production. Our results indicate that Proteobacteria, Bacterioidetes, Actinobacteria and Firmiculites were the dominant bacterial phyla across all samples. The majority of fungal sequences were assigned to Ascomycota and Basidiomycota. The bacterial genera Pseudomonas and Sphingomonas, and the fungal genera Aureobasidium and Filobasidium, represented a major component of the aboveground microbiota. Different parts of the apple plant harboured a specific microbiota and the effect of plant organ on the bacterial and fungal taxonomic structure exceeded the influence of sampling time and plant genotype. This work highlights the specificity of the microbiota associated with aboveground apple organs, changes of the microbiota composition during the plant development from orchard planting to the first year of fruit production, and the negligible effects of apple cultivar.

    Huddling together to survive: Population density as a survival strategy of non-spore forming bacteria under nutrient starvation and desiccation at solid-air interfaces

    Pashang R.Wenk J.Ronan E.Kroukamp O....
    11页
    查看更多>>摘要:? 2022 Elsevier GmbHAcclimation and flexible response mechanisms are survival adaptations allowing prokaryotic cells to colonize diverse habitats and maintain viability in nature. Lack of water significantly impacts cellular response, which can be partially compensated for through community interactions and accessing survival means beyond the cell's boundaries. In the present study, higher numbers of cultivable Gram-positive Arthrobacter sp. and Gram-negative Pseudomonas stutzeri cells were found on surfaces when high population density was used after prolonged periods of desiccation and nutrient starvation. Total cell counts during desiccation periods decreased slower than culturable cell counts independently from initial population density. The presence of homogenate, prepared by filtering homogenized cultures through a 0.2 μm filter, extended culturability of Arthrobacter sp. cells, while intact heat-killed cells extended the culturability of Arthrobacter sp. and P. stutzeri. Our results suggest very slow cell membrane breakdown for desiccated bacterial cells at solid-air interfaces over extended time spans, which may serve as reservoirs of nutrients, and may potentially provide trace amounts of water for surviving cells. Higher initial population density and recycling of resources from “zombie”-like cells, may support growth in a similar fashion as access to cell lysates or the contents of heat-killed cells analogous to dead-phase cultures where some cells experience cryptic growth.

    Fermentation products of the fungus Monascus spp. impairs the physiological activities of toxin-producing Vibrio cholerae

    Xu J.Yamashiro T.Arakaki R.Tachibana S....
    7页
    查看更多>>摘要:? 2022 The AuthorsMonascus spp. are filamentous fungi used in fermented foods. They are also natural colorants and food preservatives. Certain metabolites of Monascus spp. lower cholesterol and have other health-promoting effects in humans. In the present study, we demonstrated that the fermentation products of Monascus spp. inhibited ATP synthesis and motility in toxigenic Vibrio cholerae. Single-cell tracking and rotation assays on single flagella showed that Monascus fermentation extract (MFE) significantly impaired V. cholerae swimming by disrupting flagellar rotation. A membrane potential-sensitive carbocyanine dye revealed that MFE depolarized the V. cholerae cell membrane which, in turn, lowered the membrane potential and, by extension, restricted ATP synthesis and flagellar rotation. MFE also severely hindered the motility of other pathogenic bacteria such as V. parahaemolyticus, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, and Leptospira interrogans. The foregoing findings indicate that Monascus fermentation extract could potentially preventing infection caused by multiple pathogenic bacteria as the conventional prophylaxes and slow their progression and lower mortality and morbidity.

    Pythium oligandrum in plant protection and growth promotion: Secretion of hydrolytic enzymes, elicitors and tryptamine as auxin precursor

    Chmelik J.Kavan D.Ryslava H.Cerovska N....
    15页
    查看更多>>摘要:? 2022 Elsevier GmbHPythium is a genus of parasitic oomycetes which target plants and both nonvertebrate and vertebrate animals, including fish and mammalian species. However, several Pythium spp., such as P. oligandrum, function as mycoparasites of pathogenic fungi, bacteria, and oomycetes in soil and thus as advantageous biocontrol agents. This review primarily focuses on biochemical processes underlying their positive effects. For example, P. oligandrum degrades host cell wall polysaccharides using chitinases, cellulases, endo-β-1,3-glucanases, and various exoglycosidases. Proteases from various classes also participate in the cell wall hydrolysis. All these processes can modify cell surface structures and help Pythium spp. compete for space and nutrition. Accordingly, enzyme secretion most likely plays a key role in plant root colonisation. Plant-P. oligandrum interactions, nevertheless, do not involve tissue injury but instead activate plant defence mechanisms, thereby strengthening future plant responses to pathogen attacks. Priming induces the phenylpropanoid and terpenoid pathways and thus synthesis of secondary metabolites, including lignin, for cell wall fortification and other metabolic adjustments. Such metabolic changes are mediated by elicitins, cell wall glycoproteins and oligandrins produced by P. oligandrum. As homologous proteins of β-cinnamomin from Phytophthora cinnamomi with similar essential amino acids for sterol binding, oligandrins stand out for their structure, which they share with cell wall glycoproteins, albeit without the Ser-Thr-rich O-glycosylated domain for cell wall attachment. P. oligandrum also provides plant with tryptamine used for auxin synthesis, promoting plant growth. Overall, in addition to discussing plant metabolic and phytohormonal changes after P. oligandrum inoculation, we review data on P. oligandrum applications as researchers increasingly search for effective and environmentally friendly ways to protect crops. In this context, P. oligandrum emerges as a highly suitable biotechnological solution.

    NAD+-dependent Glsirt1 has a key role on secondary metabolism in Ganoderma lucidum

    Zhao M.Wang S.Chen X.Liu R....
    8页
    查看更多>>摘要:? 2022 Elsevier GmbHNicotinamide adenine dinucleotide (NAD+) is an important intracellular metabolite that is involved in different cel1lular processes. Glnmnat is the key enzyme that can affect intracellular NAD+ content. Here, we found that exogenous NAD+ treatment significantly increased ganoderic acid (GA) content in Ganoderma lucidum by 56.2%. Further experimental results showed that the acetylation level in Glnmnat-silenced strains significantly increased by about 35% and the transcript level of deacetylase Glsirt1 decreased by about 70%. Moreover, silencing Glnmnat led to a decrease in GA content, and this decrease could be rescued by the Glsirt1 activator. In addition, the acetylation of Glsirt1i-11 and Glsirt1i-21 was significantly increased by 28.8% and 41.0%. Furthermore, the decrease in GA content caused by silencing Glsirt1 could not be completely rescued by NAD+ treatment. Taken together, our study reveals that Glsirt1 is essential for the downstream regulation of GA biosynthesis by Glnmnat/NAD+, emphasizes the importance of acetylation modification in the mechanism of GA biosynthesis, and provides ideas for other fungi to study secondary metabolic regulatory networks in epigenetics.

    The dynamic landscape of parasitemia dependent intestinal microbiota shifting and the correlated gut transcriptome during Plasmodium yoelii infection

    Yawen Z.Binyou L.Xingchen Y.Xuedong Z....
    12页
    查看更多>>摘要:? 2022 Elsevier GmbHMalaria, caused by Plasmodium, is a global life-threatening infectious disease. However, the dynamic interactions between intestinal microbiota and host immunity during the infections are still unclear. Here, we investigated the change of intestinal microbiome and transcriptome during Plasmodium yoelii infection in mice. The mice were infected with P. yoelii through the intraperitoneal injection. The intestinal contents and tissues were collected at different time points along with the malaria procession and they were subjected to the microbiome and transcriptome sequencing and analysis respectively. The dynamic landscape of parasitemia-dependent intestinal microbiota and related host immunity were identified: (1) The diversity and composition of the intestinal microbiota represented a significant correlation with the Plasmodium infection; (2) Up-regulated genes from the intestinal transcriptome were mainly enriched in immune cell differentiation pathways, especially, naive CD4+ T cell differentiation to Th1/2 cells in the early immune response and Th17 cells in the later immune stage, T cell receptor (TCR) and B cell receptor (BCR) activation in the whole host immunity; (3) Host immune cells presented parasitemia phase-specific characteristics against P. yoelii infection; (4) There were significant associations between the parasitemia phase-specific microbiotas and the host immune response. Th1 cell differentiation was positively correlated with genera Moryella and specie Erysipelotrichaceae bacterium canine oral taxon 255, while negatively correlated with genera Ruminiclostridium. Th17 cell differentiation was related to the colonization of family Peptococcaceae, genera Lachnospiraceae FCS020 group, and specie Eubacterium plexicaudatum ASF492 and the reduction of family Bacteroidales BS11 gut group, genera Sutterella, and specie Parabacteroides distasonis str. 3776 D15 I. BCRs and TCRs were highly related with the family Bacteroidales BS11 gut group, genera Moryella, and specie Erysipelotrichaceae bacterium canine oral taxon 255, but negatively related with the genera Ruminiclostridium. Our results indicated a remarkable dynamic landscape and correlation of the parasitemia-dependent shifting of intestinal microbiota and immunity, suggesting the essential roles of intestinal microbiome on the modulation of host immunity against Plasmodium infection.

    Selected rhizosphere bacteria are associated with endangered species - Scutellaria tsinyunensis via comparative microbiome analysis

    Xu H.Yu F.Zuo Y.Dai Y....
    8页
    查看更多>>摘要:? 2021Scutellaria tsinyunensis is an endangered plant under extremely critical condition. Soil microbiome is important for plants growth. To better understand the endangered mechanism of S. tsinyunensis from the perspective of rhizosphere bacteria, we examined soil bacteria community in nearly all extant S. tsinyunensis populations at two altitude levels through high-throughput sequencing. Our co-occurrence network analysis manifested six key genera had active interactions with many genera. Moreover, we found that deterministic processes dominate rhizosphere bacterial community assembly. By constructing structural equation model, we found that pH as a key factor shaping the bacterial community, suggesting canopy density – pH – bacterial diversity regulatory model may contribute to the endangerment of S. tsinyunensis. Further, we revealed that Haliangium and Candidatus Koribacter act as essential genera for the protection of S. tsinyunensis through controlling multi combination of covariates. Together, our study revealed a holistic picture of rhizosphere microbiome and environmental factors associated with S. tsinyunensis, and provided direction for future protection of this endangered plant.

    Host-induced gene silencing reveals the role of Sclerotinia sclerotiorum oxaloacetate acetylhydrolase gene in fungal oxalic acid accumulation and virulence

    Rana K.Yuan J.Liao H.Qian W....
    8页
    查看更多>>摘要:? 2022Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating necrotrophic pathogen which causes severe yield losses to oilseed production worldwide. Most of efforts at the genetic mitigation of the disease have not been successful. Present investigation was conducted to functionally characterize the effect of down-regulating Ssoah1 during host infection and explore the possibility of boosting host resistance by silencing this gene. We utilized host-induced gene silencing (HIGS) to silence Ssoah1 gene in the S. sclerotiorum fungus. A HIGS based vector was constructed and transformed into Arabidopsis thaliana. The pathogenicity assays in the transgenic A. thaliana lines revealed three T3 transformants with significantly higher resistance to S. sclerotiorum in comparison to untransformed controls. There was a concomitant reduction in expression of Ssoah1 and accumulation of oxalic acid in the necrotic regions of transgenic lines as compared to the non-transgenic controls. Specific Ssoah1-siRNA was highly expressed in HIGS Ssoah1 transgenic lines, as compared with WT and EV plants. The outcomes of oxalic acid estimation revealed that silencing of Ssoah1 results in decreased OA accumulation. The recovered mycelium plugs from HIGS Ssoah1 transgenic lines showed decreased Ssoah1 expression and pathogenesis. These results provide the possibility of using HIGS of Ssoah1 for engineering resistance against S. sclerotiorum.