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Frontiers in Microbiology 2022The gut microbiota is key for the homeostasis of many phytophagous insects, but there are few studies comparing its role on host use by stenophagous or polyphagous...
Bitter friends are not always toxic: The loss of acetic acid bacteria and the absence of in the gut microbiota of the polyphagous fly could inhibit its development in in contrast to and that flourish in this host.
The gut microbiota is key for the homeostasis of many phytophagous insects, but there are few studies comparing its role on host use by stenophagous or polyphagous frugivores. Guava () is a fruit infested in nature by the tephritids and . In contrast, the extremely polyphagous infests guava only under artificial conditions, but unlike and the Mexican , it infests bitter oranges (). We used these models to analyze whether the gut microbiota could explain the differences in host use observed in these flies. We compared the gut microbiota of the larvae of the three species when they developed in guava and the microbiota of the fruit pulp larvae fed on. We also compared the gut microbiota of developing in . with the pulp microbiota of this widely used host. The three flies modified the composition of the host pulp microbiota (i.e., pulp the larvae fed on). We observed a depletion of Acetic Acid Bacteria (AAB) associated with a deleterious phenotype in when infesting . In contrast, the ability of and to infest this fruit is likely associated to a symbiotic interaction with species of the genus, which are known to degrade a wide spectrum of tannins and polyphenols. The three flies establish genera specific symbiotic associations with AABs. In the case of , the association is with and , but importantly, it cannot be colonized by , a factor likely inhibiting its development in guava.
PubMed: 36246214
DOI: 10.3389/fmicb.2022.979817 -
Biosensors Aug 2022Microbial fuel cells (MFCs) are a variety of bioelectrocatalytic devices that utilize the metabolism of microorganisms to generate electric energy from organic matter....
Microbial fuel cells (MFCs) are a variety of bioelectrocatalytic devices that utilize the metabolism of microorganisms to generate electric energy from organic matter. This study investigates the possibility of using a novel PEDOT:PSS/graphene/Nafion composite in combination with acetic acid bacteria to create a pure culture MFC capable of effective municipal wastewater treatment. The developed MFC was shown to maintain its activity for at least three weeks. The level of COD in municipal wastewater treatment was reduced by 32%; the generated power was up to 81 mW/m with a Coulomb efficiency of 40%. Combining the MFC with a DC/DC boost converter increased the voltage generated by two series-connected MFCs from 0.55 mV to 3.2 V. A maximum efficiency was achieved on day 8 of MFC operation and was maintained for a week; capacitors of 6800 µF capacity were fully charged in ~7 min. Thus, cells can become an important part of microbial consortia in MFCs used for treatment of wastewaters with reduced pH.
Topics: Bioelectric Energy Sources; Bridged Bicyclo Compounds, Heterocyclic; Electricity; Electrodes; Fluorocarbon Polymers; Gluconobacter oxydans; Graphite; Polymers; Wastewater; Water Purification
PubMed: 36140084
DOI: 10.3390/bios12090699 -
Insects Aug 2022Queen bees and worker bees both develop from fertilized eggs, whereas queens live longer than workers. The mechanism of this phenomenon is worth exploring. Antioxidant...
The Comparison of Antioxidant Performance, Immune Performance, IIS Activity and Gut Microbiota Composition between Queen and Worker Bees Revealed the Mechanism of Different Lifespan of Female Casts in the Honeybee.
Queen bees and worker bees both develop from fertilized eggs, whereas queens live longer than workers. The mechanism of this phenomenon is worth exploring. Antioxidant capacity, immune and IIS are the conserved mechanisms of aging. The importance of gut bacteria for health prompted us to connect with bee aging. Therefore, the differences of antioxidant, immune, IIS and gut microflora between queen and worker bees were compared to find potential mechanisms of queens' longevity. The results showed queens had stronger antioxidant capacity and lower immune pathway and IIS activity than workers. The higher expression level of and in queens resulted in the stronger ROS scavenging ability, which leads to the lower ROS level and the reduced accumulation of oxidative damage products in queens. The lower expression and higher antimicrobial peptides (AMPs) expressions in queens suggested that queens maintain lower immune pathway activity and stronger immune capacity than workers. Gut bacteria composition analysis indicated that queens had supernal Acetobacteraceae (notably , and over workers. In conclusion, antioxidant, immune, IIS, and gut symbiotic bacteria all contribute to the longevity of queens. This study provides more insights into revealing the mechanisms of queens' longevity.
PubMed: 36135473
DOI: 10.3390/insects13090772 -
Applied and Environmental Microbiology Sep 2022In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic... (Review)
Review
In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic two-step fermentation process performed by Gluconobacter oxydans, Bacillus megaterium, and Ketogulonicigenium vulgare. In the second step of the two-step fermentation process, the microbial consortium of and B. megaterium is used to achieve 2-KLG production. can transform l-sorbose to 2-KLG, but the yield of 2-KLG is much lower in the monoculture than in the coculture fermentation system. The relationship between the two strains is too diverse to analyze and has been a hot topic in the field of vitamin C fermentation. With the development of omics technology, the relationships between the two strains are well explained; nevertheless, the cell-cell communication is unclear. In this review, based on current omics results, the interactions between the two strains are summarized, and the potential cell-cell communications between the two strains are discussed, which will shed a light on the further understanding of synthetic consortia.
Topics: Ascorbic Acid; Fermentation; Gluconobacter oxydans; Microbial Interactions; Rhodobacteraceae; Sorbose; Sugar Acids; Vitamins
PubMed: 36073939
DOI: 10.1128/aem.01212-22 -
PloS One 2022Mosquitoes transmit many pathogens responsible for human diseases, such as malaria which is caused by parasites in the genus Plasmodium. Current strategies to control...
Mosquitoes transmit many pathogens responsible for human diseases, such as malaria which is caused by parasites in the genus Plasmodium. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance, so additional methods of control are required. Paratransgenesis is a method whereby symbiotic bacteria are genetically modified to affect the mosquito's phenotype by engineering them to deliver effector molecules into the midgut to kill parasites. One paratransgenesis candidate is Asaia bogorensis, a Gram-negative bacterium colonizing the midgut, ovaries, and salivary glands of Anopheles sp. mosquitoes. Previously, engineered Asaia strains using native signals to drive the release of the antimicrobial peptide, scorpine, fused to alkaline phosphatase were successful in significantly suppressing the number of oocysts formed after a blood meal containing P. berghei. However, these strains saw high fitness costs associated with the production of the recombinant protein. Here, we report evaluation of five different partner proteins fused to scorpine that were evaluated for effects on the growth and fitness of the transgenic bacteria. Three of the new partner proteins resulted in significant levels of protein released from the Asaia bacterium while also significantly reducing the prevalence of mosquitoes infected with P. berghei. Two partners performed as well as the previously tested Asaia strain that used alkaline phosphatase in the fitness analyses, but neither exceeded it. It may be that there is a maximum level of fitness and parasite inhibition that can be achieved with scorpine being driven constitutively, and that use of a Plasmodium specific effector molecule in place of scorpine would help to mitigate the stress on the symbionts.
Topics: Acetobacteraceae; Alkaline Phosphatase; Animals; Biological Control Agents; Defensins; Malaria; Mosquito Vectors; Plasmodium; Recombinant Proteins
PubMed: 36048823
DOI: 10.1371/journal.pone.0273568 -
International Journal of Molecular... Aug 2022has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis...
has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis of the early transcriptional response of exponentially growing to iron, an essential cofactor for many enzymes involved in various metabolic pathways. RNA-seq, targeted gene mutagenesis and computational motif discovery tools were used to define the regulon. The data analysis showed that genes encoding functions related to iron homeostasis were significantly upregulated in response to iron limitations. Certain genes involved in secondary metabolism were overexpressed under iron-limited conditions. In contrast, it was observed that the expression of genes involved in Fe-S cluster biosynthesis, flagellar biosynthesis and type IV secretion systems were downregulated in an iron-depleted culture medium. Our results support a model that controls transcription in by function. The protein was able to complement an mutant. These results provide new insights into the effects of iron on the metabolism of , as well as demonstrate the essentiality of this micronutrient for the main characteristics of plant growth promotion by .
Topics: Bacterial Proteins; Culture Media; Gluconacetobacter; Iron; Transcriptome
PubMed: 35955667
DOI: 10.3390/ijms23158533 -
Frontiers in Microbiology 2022This study investigates the isolation, identification, and fermentation performance of autochthonous acetic acid bacteria (AAB) from local niche habitats on the Island...
This study investigates the isolation, identification, and fermentation performance of autochthonous acetic acid bacteria (AAB) from local niche habitats on the Island of Gozo (Malta) and their further use for vinegar production, employing local raw materials. The bacteria were isolated from grapevine berries and vinegar produced in the cottage industry. Following phenotype and genotype identification, the AAB were ascribed to the genera , and . A mixture of selected AAB was tested as an inoculum for vinegar production in bench fermenters, under different conditions and substrates, namely, grapes, honey, figs, onions, prickly pear, and tomatoes. The bench fermenters were operated under semi-continuous fermentation where working volumes were maintained by discharging and subsequent recharging accordingly to maintain the acidity in fermenters by adding 30-50 g/l of acetic acid for optimal performance. Finally, the vinegar products obtained from the different substrates were evaluated for their quality, including organoleptic properties, which showed the superior quality of wood-treated vinegar samples with respect to neat vinegar samples.
PubMed: 35928157
DOI: 10.3389/fmicb.2022.897825 -
International Journal of Molecular... Jul 2022Bacterial cellulose is a natural polymer with an expanding array of applications. Because of this, the main cellulose producers of the genus have been extensively...
Bacterial cellulose is a natural polymer with an expanding array of applications. Because of this, the main cellulose producers of the genus have been extensively studied with the aim to increase its synthesis or to customize its physicochemical features. Up to now, the genetic studies in have focused on the first cellulose synthase operon () encoding the main enzyme complex. However, the role of other accessory cellulose operons has been understudied. Here we aimed to fill this gap by performing a detailed analysis of the second cellulose synthase operon (), which is putatively linked with cellulose acylation. In this study we harnessed the genome sequence, gene expression and protein structure information of E25 and other species to discuss the probable features of and the biochemical function of its main protein products. The results of our study support the previous hypothesis that is involved in the synthesis of the acylated polymer and expand it by presenting the evidence that it may also function in the regulation of its attachment to the cell surface and to the crystalline cellulose fibers.
Topics: Acetobacteraceae; Cellulose; Gluconacetobacter xylinus; Glucosyltransferases; Operon
PubMed: 35887199
DOI: 10.3390/ijms23147851 -
Journal of Microbiology and... Aug 2022Kombucha mutualistic community (KMC) is composed by acetic acid bacteria and yeasts, producing fermented tea with health benefits. As part of the BIOlogy and Mars...
Kombucha mutualistic community (KMC) is composed by acetic acid bacteria and yeasts, producing fermented tea with health benefits. As part of the BIOlogy and Mars EXperiment (BIOMEX) project, the effect of Mars-like conditions on the KMC was analyzed. Here, we analyzed metagenome-assembled genomes (MAGs) of the , which is a predominant genus in KMC, to understand their roles in the KMC after exposure to Mars-like conditions (outside the International Space Station) based on functional genetic elements. We constructed three MAGs: , , and . Our results showed that (i) MAG functionally more complex than , (ii) is a keystone in KMCs with specific functional features to tolerate extreme stress, and (iii) genes related to the PPDK, betaine biosynthesis, polyamines biosynthesis, sulfate-sulfur assimilation pathway as well as type II toxin-antitoxin (TA) system, quorum sensing (QS) system, and cellulose production could play important roles in the resilience of KMC after exposure to Mars-like stress. Our findings show the potential mechanisms through which tolerates the extraterrestrial stress and will help to understand minimal microbial composition of KMC for space travelers.
Topics: Acetobacteraceae; Cellulose; Metagenome; Yeasts
PubMed: 35879284
DOI: 10.4014/jmb.2204.04009 -
Toxins Jun 2022Patulin is a mycotoxin that primarily contaminate apples and apple products. Whole cell or cell-free extracts of ATCC 621 were able to transform patulin to E-ascladiol....
Patulin is a mycotoxin that primarily contaminate apples and apple products. Whole cell or cell-free extracts of ATCC 621 were able to transform patulin to E-ascladiol. Proteins from cell-free extracts were separated by anion exchange chromatography and fractions with patulin transformation activity were subjected to peptide mass fingerprinting, enabling the identification of two NADPH dependent short chain dehydrogenases, GOX0525 and GOX1899, with the requisite activity. The genes encoding these enzymes were expressed in and purified. Kinetic parameters for patulin reduction, as well as pH profiles and thermostability were established to provide further insight on the potential application of these enzymes for patulin detoxification.
Topics: Escherichia coli; Furans; Gluconobacter oxydans; Malus; Oxidoreductases; Patulin
PubMed: 35878161
DOI: 10.3390/toxins14070423