Bacterial and Fungal Microbiota of Guinea Grass Silage Shows Various Levels of Acetic Acid Fermentation

This study aimed to gain insights into the bacterial and fungal microbiota associated with the acetic acid fermentation of tropical grass silage. Direct-cut (DC, 170 g dry matter [DM]/kg) and wilted (WT, 323 g DM/kg) guinea grass were stored in a laboratory silo at moderate (25 °C) and high (40 °C) temperatures. Bacterial and fungal microbiota were assessed at 3 days, 1 month, and 2 months after ensiling. Lactic acid was the primary fermentation product during the initial ensiling period, and a high Lactococcus abundance (19.7–39.7%) was found in DC silage. After two months, the lactic acid content was reduced to a negligible level, and large amounts of acetic acid, butyric acid, and ethanol were found in the DC silage stored at 25 °C. The lactic acid reduction and acetic acid increase were suppressed in the DC silage stored at 40 °C. Increased abundances of Lactobacillus, Clostridium, and Wallemia, as well as decreased abundances of Saitozyma, Papiliotrema, and Sporobolomyces were observed in DC silages from day three to the end of the 2 month period. Wilting suppressed acid production, and lactic and acetic acids were found at similar levels in WT silages, regardless of the temperature and storage period. The abundance of Lactobacillus (1.72–8.64%) was lower in WT than in DC silages. The unclassified Enterobacteriaceae were the most prevalent bacteria in DC (38.1–64.9%) and WT (50.9–76.3%) silages, and their abundance was negatively related to the acetic acid content. Network analysis indicated that Lactobacillus was involved in enhanced acetic acid fermentation in guinea grass silage.

Diversidade da microbiota de fungos da própolis in natura / Diversity of in natura propolis fungal microbiota

O presente estudo teve por objetivo realizar a identificação dos fungos encontrados na própolis produzido por Apis mellifera L. da Baía do Iguape, Brasil. Para tanto, foram utilizadas técnicas morfológicas, bioquímicas e moleculares, sendo averiguado o perfil de restrição gerado por espaçador interno transcrito (ITS1 e ITS4). O tamanho dos produtos de PCR foi analisado quanto ao perfil de restrição obtidos com endonuclease (HhaI, HaeIII e HinfI) por espécie. Foram identificadas dezesseis espécies de fungos filamentosos: Flavodon flavus, Aspergillus nomius, Aspergillus versicolor, Cladosporium sp., Coniothyrium sidae, Didymella sp., Paecilomyces variotii, Cladosporium cladosporioides, Penicillium citrinum, Fusarium incarnatum, Penicillium chermesinum, Phoma sp., Stagonosporopsis valerianellae, Phoma medicaginis, Paraphoma fimeti e Stagonosporopsis cucurbitacearum; e seis espécies de leveduras: Candida tropicalis, Candida guiliermondii, Candida famata, Kodomala ohmeri, Trichosporon asahiu e Cryptococcus laurentii. Stagonosporopsis cucurbitacearum e leveduras pertencentes ao gênero Candida foram os microrganismos de maior ocorrência nas amostras da própolis provenientes da Baía do Iguape, Brasil.

Butyrate-producing gut bacteria are associated with protection from allergic symptoms after Hurricane Harvey

Hurricane Harvey caused record-breaking, catastrophic flooding across the city of Houston. After floodwaters receded, several health concerns arose, including the potential adverse impact of exposure to mold in flooded homes. We rapidly launched the Houston Hurricane Harvey Health Study to evaluate if microbiome sampling in the wake of a disaster could inform flood-associated environmental exposures and adverse health outcomes. We enrolled a total of 347 subjects at 1-month and 12-months post-Harvey, collecting human (stool, nasal, saliva) and environmental (house swab) samples to profile the bacterial and fungal microbiota. Here we show reported exposure to mold was associated with increased risk of allergic symptoms for up to one year post-disaster, and that butyrate-producing bacteria in the gut were linked to protection from allergic symptoms in mold-exposed individuals. Together, these data provide new insights into how microbiome:environment interactions may influence health in the setting of a flood-related disaster.

Isolation and identification of microbiota from Egyptian common insect pests invading economically important crops

Insects bodies contain multiple distinctive microbial colonies which play key role in the metabolism, development and health of an insect. In the current study bacterial and fungal microbiota were isolated from larval feces and adult wings of two major insect pests in Egypt, the Cotton leaf worm Spodoptera littoralis and the black cutworm Agrotis ipsilon. Isolated pathogens were identified and characterized according to the scientific described methods in such cases. Two different genera of bacteria (Bacillus & Serratia) were isolated from larval feces of both insects while isolated fungus were Paecilomyces variotii and Absidia corymbifera from the feces of A. ipsilon larvae, while Rhozopus stolonifer and Penicillium chrysogenum were isolated from adults wings of the same insect. The fungus Aspergillus flavus, Aspergillus niger and Mucor circinilloides were isolated from feces of S. littoralis larvae. Numerous species of bacteria and fungi had been documented as a bio-agent against many insect pests, and most of them exhibited disruption in life-cycle of different species of Lepidopterous pests. The obtained data sheds light on microbial colonies associated with two major insect pests, however further studies are required to involve the isolated microbiota in the biological control programs of insect pests.

Bacterial Inhibition on Beauveria bassiana Contributes to Microbiota Stability in Delia antiqua

Given the multiple roles of associated microbiota in improving animal host fitness in a microbial environment, increasing numbers of researchers have focused on how the associated microbiota keeps stable under complex environmental factors, especially some biological ones. Recent studies show that associated microbiota interacts with pathogenic microbes. However, whether and how the interaction would influence microbiota stability is limitedly investigated. Based on the interaction among Delia antiqua, its associated microbiota, and one pathogen Beauveria bassiana, the associated microbiota's response to the pathogen was determined in this study. Besides, the underlying mechanism for the response was also preliminarily investigated. Results showed that B. bassiana neither infect D. antiqua larvae nor did it colonize inside the associated microbiota, and both the bacterial and fungal microbiota kept stable during the interaction. Further experiments showed that bacterial microbiota almost completely inhibited conidial germination and mycelial growth of B. bassiana during its invasion, while fungal microbiota did not inhibit conidial germination and mycelial growth of B. bassiana. According to the above results, individual dominant bacterial species were isolated, and their inhibition on conidial germination and mycelial growth of B. bassiana was reconfirmed. Thus, these results indicated that bacterial instead of fungal microbiota blocked B. bassiana conidia and stabilized the associated microbiota of D. antiqua larvae during B. bassiana invasion. The findings deepened the understanding of the role of associated microbiota–pathogen microbe interaction in maintaining microbiota stability. They may also contribute to the development of novel biological control agents and pest management strategies.

Accelerated Alcoholic Fermentation of Intact Grapes by Saccharomyces Cerevisiae in Symbiosis with Microbial Community Inhabiting Grape-skin

Saccharomyces cerevisiae, an essential player in alcoholic fermentation during winemaking, is rarely found in intact grapes. Here, we addressed symbiotic interactions between S. cerevisiae and grape-skin residents upon spontaneous wine fermentation. When glucose was used as a carbon source, the yeast-like fungus Aureobasidium pullulans, a major grape-skin resident, had no effect on alcoholic fermentation by S. cerevisiae. In contrast, when intact grape berries as a sole carbon source, coculture of S. cerevisiae and A. pullulans accelerated alcoholic fermentation. Thus, grape-inhabiting microorganisms may increase carbon availability by degrading and/or incorporating grape-skin materials, such as cell wall and cuticles. A. pullulans exhibited broad spectrum assimilation of plant-derived carbon sources, including ω-hydroxy fatty acids, arising from degradation of cutin. In fact, yeast-type cutinase was produced from A. pullulans EXF-150 strain. The degradation and utilization of grape-skin materials by fungal microbiota may account for their colonization on grape-skin and symbiotic interactions with S. cerevisiae.