Taking insight into the gut microbiota of three spider species: No characteristic symbiont was found corresponding to the special feeding style of spiders

Microorganisms in insect guts have been recognized as having a great impact on their hosts' nutrition, health, and behavior. Spiders are important natural enemies of pests, and the composition of the gut microbiota of spiders remains unclear. Will the bacterial taxa in spiders be same as the bacterial taxa in insects, and what are the potential functions of the gut bacteria in spiders? To gain insight into the composition of the gut bacteria in spiders and their potential function, we collected three spider species, Pardosa laura, Pardosa astrigera, and Nurscia albofasciata, in the field, and high‐throughput sequencing of the 16S rRNA V3 and V4 regions was used to investigate the diversity of gut microbiota across the three spider species. A total of 23 phyla and 150 families were identified in these three spider species. The dominant bacterial phylum across all samples was Proteobacteria. Burkholderia, Ralstonia, Ochrobactrum, Providencia, Acinetobacter, Proteus, and Rhodoplanes were the dominant genera in the guts of the three spider species. The relative abundances of Wolbachia and Rickettsiella detected in N. albofasciata were significantly higher than those in the other two spider species. The relative abundance of Thermus, Amycolatopsis, Lactococcus, Acinetobacter Microbacterium, and Koribacter detected in spider gut was different among the three spider species. Biomolecular interaction networks indicated that the microbiota in the guts had complex interactions. The results of this study also suggested that at the genus level, some of the gut bacteria taxa in the three spider species were the same as the bacteria in insect guts.     

Complexity and variability of gut commensal microbiota in polyphagous lepidopteran larvae

Background

The gut of most insects harbours nonpathogenic microorganisms. Recent work suggests that gut microbiota not only provide nutrients, but also involve in the development and maintenance of the host immune system. However, the complexity, dynamics and types of interactions between the insect hosts and their gut microbiota are far from being well understood.

Methods/Principal Findings

To determine the composition of the gut microbiota of two lepidopteran pests, Spodoptera littoralis and Helicoverpa armigera, we applied cultivation-independent techniques based on 16S rRNA gene sequencing and microarray. The two insect species were very similar regarding high abundant bacterial families. Different bacteria colonize different niches within the gut. A core community, consisting of Enterococci, Lactobacilli, Clostridia, etc. was revealed in the insect larvae. These bacteria are constantly present in the digestion tract at relatively high frequency despite that developmental stage and diet had a great impact on shaping the bacterial communities. Some low-abundant species might become dominant upon loading external disturbances; the core community, however, did not change significantly. Clearly the insect gut selects for particular bacterial phylotypes.

Conclusions

Because of their importance as agricultural pests, phytophagous Lepidopterans are widely used as experimental models in ecological and physiological studies. Our results demonstrated that a core microbial community exists in the insect gut, which may contribute to the host physiology. Host physiology and food, nevertheless, significantly influence some fringe bacterial species in the gut. The gut microbiota might also serve as a reservoir of microorganisms for ever-changing environments. Understanding these interactions might pave the way for developing novel pest control strategies.     

Metagenomic analysis reveals changes of the Drosophila suzukii microbiota in the newly colonized regions

The spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a highly polyphagous pest of a wide variety of wild or cultivated berry and stone fruit. Originating from Southeast Asia, it has recently invaded a wide range of regions in Europe and North America. It is well known that insect microbiotas may significantly influence several aspects of the host biology and play an important role in invasive species introduction into new areas. However, in spite of the great economic importance of D. suzukii, a limited attention has been given so far to its microbiota. In this study, we present the first in‐depth characterization of gut bacterial diversity from field (native and invasive range) and lab‐reared populations of this insect. The gut bacterial communities of field insects were dominated, regardless of their origin, by 2 families of the phylum Proteobacteria: Acetobacteraceae and Enterobacteriaceae, while Firmicutes, mainly represented by the family Staphylococcaceae, prevailed in lab‐reared population. Locality was the most significant factor in shaping the microbiota of wild flies. Moreover, a negative correlation between diversity and abundance of Enterobacteriaceae and the time elapsed since the establishment of D. suzukii in a new region was observed. Altogether our results indicate that habitat, food resources as well as the colonization phase of a new region contribute to shape the bacterial communities of the invasive species which, in turn, by evolving more quickly, could influence host adaptation in a new environment.     

Increased Expression of Colonic Mucosal Melatonin in Patients with Irritable Bowel Syndrome Correlated with Gut Dysbiosis

Dysregulation of the gut microbiota/gut hormone axis contributes to the pathogenesis of irritable bowel syndrome (IBS). Melatonin plays a beneficial role in gut motility and immunity. However, altered expression of local mucosal melatonin in IBS and its relationship with the gut microbiota remain unclear. Therefore, we aimed to detect the colonic melatonin levels and microbiota profiles in patients with diarrhea-predominant IBS (IBS-D) and explore their relationship in germ-free (GF) rats and BON-1 cells. Thirty-two IBS-D patients and twenty-eight healthy controls (HCs) were recruited. Fecal specimens from IBS-D patients and HCs were separately transplanted into GF rats by gavage. The levels of colon mucosal melatonin were assessed by immunohistochemical methods, and fecal microbiota communities were analyzed using 16S rDNA sequencing. The effect of butyrate on melatonin synthesis in BON-1 cells was evaluated by ELISA. Melatonin levels were significantly increased and negatively correlated with visceral hypersensitivity in IBS-D patients. GF rats inoculated with fecal microbiota from IBS-D patients had high colonic melatonin levels. Butyrate-producing Clostridium cluster XIVa species, such as Roseburia species and Lachnospira species, were positively related to colonic mucosal melatonin expression. Butyrate significantly increased melatonin secretion in BON-1 cells. Increased melatonin expression may be an adaptive protective mechanism in the development of IBS-D. Moreover, some Clostridium cluster XIVa species could increase melatonin expression via butyrate production. Modulation of the gut hormone/gut microbiota axis offers a promising target of interest for IBS in the future.     

Comparative study on gut microbiota in three Anura frogs from a mountain stream

Composition and diversity in gut microbiota are impacted by a wide variety of factors. The similarity of gut microbiota in related or sympatric species has been gaining recent traction. Here, 16S rRNA gene sequencing technology was employed to study the gut microbiota of three sympatric frog species, namely Odorrana tormota, O. graminea, and Amolops wuyiensis. In these three frog species, the most abundant phylum was Proteobacteria, followed by Bacteroidetes, Verrucomicrobia, and Firmicutes. The most abundant family was Burkholderiaceae in three species. The most dominant genera were Burkholderia, Caballeronia, and Paraburkholderia with the highest relative abundance in O. tormota, O. graminea, and A. wuyiensis, respectively. No differences were observed in alpha diversity indexes among the three frog species. However, bacterial similarity of gut microbiota was significantly different between O. tormota and A. wuyiensis and between O. graminea and A. wuyiensis. Metabolism‐related gene function was predominantly enriched in the gut microbiota of the three evaluated frog species. From these findings, that the relative abundance of the gut microbiota and predicted gene functions differed in three species, we conclude that there were significant differences in the gut microbiota of the three species. Similar alpha diversity and interspecific bacterial similarity in the gut might be related to bacterial transmission among the three Anura frogs evaluated in this study.     

A standardized approach for co-culturing dothidealean rock-inhabiting fungi and lichen photobionts in vitro

Owing to the effect of symbiotic gut bacteria on the proliferation of infectious disease-transferring insects and their potential as paratransgenic tools, their identification or securing their use in controlling insect vectors is urgently needed. Bradysia agrestis is one of the major plant epidemic vectors in East Asia; however, its normal microbiota remains unstudied. This research was primarily designed to secure promising candidates for use in a paratransgenic approach to phytopathogen control, as well as to provide a picture of the gut microbiota of wild-caught B. agrestis from a blight field. A total of 180 larvae from three different regions in South Korea were analyzed for their gut microfloral composition. Diverse bacterial strains were purely isolated based on morphological differences in microbiological media. We found a total of 64 bacterial strains in the B. agrestis midgut and analyzed their 16S rRNA gene sequences for molecular identification and phylogenetic characterization. Furthermore, the microbial diversity of each normal microbiota group was analyzed with various diversity indices. Bacterial biota including species diversity, richness or species distribution, species constituents, and dominance varied by each regional vector group. The most widely distributed species was Bacillus aryabhattai, and the most common genera were Bacillus and Microbacterium. These saprophytic bacteria were isolated from all regional groups and their potential as paratransgenic candidates for controlling B. agrestis-mediated plant disease is discussed.     

Analysis of the Gut Microbiota by High-Throughput Sequencing of the V5–V6 Regions of the 16S rRNA Gene in Donkey

Considerable evidence suggests that the gut microbiota is complex in many mammals and gut bacteria communities are essential for maintaining gut homeostasis. To date the research on the gut microbiota of donkey is surprisingly scarce. Therefore, we performed high-throughput sequencing of the 16S rRNA genes V5–V6 hypervariable regions from gut fecal material to characterize the gut microbiota of healthy donkeys and compare the difference of gut microbiota between male and female donkeys. Sixty healthy donkeys (30 males and 30 females) were enrolled in the study, a total of 915,691 validated reads were obtained, and the bacteria found belonged to 21 phyla and 183 genera. At the phylum level, the bacterial community composition was similar for the male and female donkeys and predominated by Firmicutes (64 % males and 64 % females) and Bacteroidetes (23 % males and 21 % females), followed by Verrucomicrobia, Euryarchaeota, Spirochaetes, and Proteobacteria. At the genus level, Akkermansia was the most abundant genus (23 % males and 17 % females), followed by Sporobacter, Methanobrevibacter, and Treponema, detected in higher distribution proportion in males than in females. On the contrary, Acinetobacter and Lysinibacillus were lower in males than in females. In addition, six phyla and 15 genera were significantly different between the male and female donkeys for species abundance. These findings provide previously unknown information about the gut microbiota of donkeys and also provide a foundation for future investigations of gut bacterial factors that may influence the development and progression of gastrointestinal disease in donkey and other animals.     

Extracellular Vesicles Derived from Gut Microbiota,Especially Akkermansia muciniphila,Protect the Progression of Dextran Sulfate Sodium-Induced Colitis

Gut microbiota play an important part in the pathogenesis of mucosal inflammation, such as inflammatory bowel disease (IBD). However, owing to the complexity of the gut microbiota, our understanding of the roles of commensal and pathogenic bacteria in the maintenance of immune homeostasis in the gut is evolving only slowly. Here, we evaluated the role of gut microbiota and their secreting extracellular vesicles (EV) in the development of mucosal inflammation in the gut. Experimental IBD model was established by oral application of dextran sulfate sodium (DSS) to C57BL/6 mice. The composition of gut microbiota and bacteria-derived EV in stools was evaluated by metagenome sequencing using bacterial common primer of 16S rDNA. Metagenomics in the IBD mouse model showed that the change in stool EV composition was more drastic, compared to the change of bacterial composition. Oral DSS application decreased the composition of EV from Akkermansia muciniphila and Bacteroides acidifaciens in stools, whereas increased EV from TM7 phylum, especially from species DQ777900_s and AJ400239_s. In vitro pretreatment of A. muciniphila-derived EV ameliorated the production of a pro-inflammatory cytokine IL-6 from colon epithelial cells induced by Escherichia coli EV. Additionally, oral application of A. muciniphila EV also protected DSS-induced IBD phenotypes, such as body weight loss, colon length, and inflammatory cell infiltration of colon wall. Our data provides insight into the role of gut microbiota-derived EV in regulation of intestinal immunity and homeostasis, and A. muciniphila-derived EV have protective effects in the development of DSS-induced colitis.     

Diet strongly influences the gut microbiota of surgeonfishes

Intestinal tracts are among the most densely populated microbial ecosystems. Gut microbiota and their influence on the host have been well characterized in terrestrial vertebrates but much less so in fish. This is especially true for coral reef fishes, which are among the most abundant groups of vertebrates on earth. Surgeonfishes (family: Acanthuridae) are part of a large and diverse family of reef fish that display a wide range of feeding behaviours, which in turn has a strong impact on the reef ecology. Here, we studied the composition of the gut microbiota of nine surgeonfish and three nonsurgeonfish species from the Red Sea. High‐throughput pyrosequencing results showed that members of the phylum Firmicutes, especially of the genus Epulopiscium, were dominant in the gut microbiota of seven surgeonfishes. Even so, there were large inter‐ and intraspecies differences in the diversity of surgeonfish microbiota. Replicates of the same host species shared only a small number of operational taxonomic units (OTUs), although these accounted for most of the sequences. There was a statistically significant correlation between the phylogeny of the host and their gut microbiota, but the two were not completely congruent. Notably, the gut microbiota of three nonsurgeonfish species clustered with some surgeonfish species. The microbiota of the macro‐ and microalgavores was distinct, while the microbiota of the others (carnivores, omnivores and detritivores) seemed to be transient and dynamic. Despite some anomalies, both host phylogeny and diet were important drivers for the intestinal microbial community structure of surgeonfishes from the Red Sea.     

Consistent Alterations of Human Fecal Microbes After Transplantation into Germ-free Mice

Fecal microbiota transplantation (FMT) of human fecal samples into germ-free (GF) mice is useful for establishing causal relationships between the gut microbiota and human phenotypes. However, due to the intrinsic differences between human and mouse intestines and the different diets of the two organisms, it may not be possible to replicate human phenotypes in mice through FMT; similarly, treatments that are effective in mouse models may not be effective in humans. In this study, we aimed to identify human gut microbes that undergo significant and consistent changes (i.e., in relative abundances) after transplantation into GF mice in multiple experimental settings. We collected 16S rDNA-seq data from four published studies and analyzed the gut microbiota profiles from 1713 human–mouse pairs. Strikingly, on average, we found that only 47% of the human gut microbes could be re-established in mice at the species level, among which more than 1/3 underwent significant changes (referred to as “variable taxa”). Most of the human gut microbes that underwent significant changes were consistent across multiple human–mouse pairs and experimental settings. Consequently, about 1/3 of human samples changed their enterotypes, i.e., significant changes in their leading species after FMT. Mice fed with a controlled diet showed a lower enterotype change rate (23.5%) than those fed with a noncontrolled diet (49.0%), suggesting a possible solution for rescue. Most of the variable taxa have been reported to be implicated in human diseases, with some recognized as the causative species. Our results highlight the challenges of using a mouse model to replicate human gut microbiota-associated phenotypes, provide useful information for researchers using mice in gut microbiota studies, and call for additional validations after FMT. An online database named FMT-DB is publicly available at http://fmt2mice.humangut.info/#/.     

Alterations in the diversity and composition of mice gut microbiota by lytic or temperate gut phage treatment

Phages, the most abundant species in the mammalian gut, have numerous advantages as biocontrol agent over antibiotics. In this study, mice were orally treated with the lytic gut phage PA13076 (group B), the temperate phage BP96115 (group C), no phage (group A), or streptomycin (group D) over 31 days. At the end of the experiment, fecal microbiota diversity and composition was determined and compared using high-throughput sequencing of the V3–V4 hyper-variable region of the 16S rRNA gene and virus-like particles (VLPs) were quantified in feces. There was high diversity and richness of microbiota in the lytic and temperate gut phage-treated mice, with the lytic gut phage causing an increased alpha diversity based on the Chao1 index (p < 0.01). However, the streptomycin treatment reduced the microbiota diversity and richness (p = 0.0299). Both phage and streptomycin treatments reduced the abundance of Bacteroidetes at the phylum level (p < 0.01) and increased the abundance of the phylum Firmicutes. Interestingly, two beneficial genera, Lactobacillus and Bifidobacterium, were enhanced by treatment with the lytic and temperate gut phage. The abundance of the genus Escherichia/Shigella was higher in mice after temperate phage administration than in the control group (p < 0.01), but lower than in the streptomycin group. Moreover, streptomycin treatment increased the abundance of the genera Klebsiella and Escherichia/Shigella (p < 0.01). In terms of the gut virome, fecal VLPs did not change significantly after phage treatment. This study showed that lytic and temperate gut phage treatment modulated the composition and diversity of gut microbiota and the lytic gut phage promoted a beneficial gut ecosystem, while the temperate phage may promote conditions enabling diseases to occur.

     

肠道微生物菌群共存网络的构建与分析

【目的】将网络分析应用到肠道微生物的分析之中,探究肠道微生物共存网络拓扑结构等相关网络系数的分析,从而展现肠道微生物共存网络的特性。【方法】将之前研究中的肠道微生物数据根据雌马酚代谢能力划分成雌马酚产生者和非产生者两组,计算两组微生物相对丰度,得出菌种之间的相关系数,构建肠道微生物的共存网络,分析两组间共存网络参数的差异;运用随机网络检验现实网络拓扑结构的特异性,分析两组网络中菌种间的差异。【结果】共存网络中两组节点数分别为45个和47个,即分别有45个和47个不同菌种。比较两组网络结构的差异,发现雌马酚产生者组中的共存网络菌群具有更复杂的连接,且两组之间的其他网络参数存在一定的差异。通过将现实网络与随机网络对比可知,现实网络的拓扑结构具有一定的特异性。将具有代谢雌马酚相关物质能力的菌种在两组网络中标出,发现它们在雌马酚产生者组共存网络中更趋向与来自不同门的菌种产生相互联系。【结论】将网络分析应用于肠道微生物分析之中,可以发掘菌种之间的相互作用和网络拓扑结构的复杂性与差异性,展现肠道菌群结构中之前较少被认识到的一些特征。因而,网络分析的方法可以为未来肠道微生物的研究提供新的视角。     

Characterization of Changes and Driver Microbes in Gut Microbiota During Healthy Aging Using A Captive Monkey Model

Recent population studies have significantly advanced our understanding of how age shapes the gut microbiota. However, the actual role of age could be inevitably confounded due to the complex and variable environmental factors in human populations. A well-controlled environment is thus necessary to reduce undesirable confounding effects, and recapitulate age-dependent changes in the gut microbiota of healthy primates. Herein we performed 16S rRNA gene sequencing, characterized the age-associated gut microbial profiles from infant to elderly crab-eating macaques reared in captivity, and systemically revealed the lifelong dynamic changes of the primate gut microbiota. While the most significant age-associated taxa were mainly found as commensals such as Faecalibacterium, the abundance of a group of suspicious pathogens such as Helicobacter was exclusively increased in infants, underlining their potential role in host development. Importantly, topology analysis indicated that the network connectivity of gut microbiota was even more age-dependent than taxonomic diversity, and its tremendous decline with age could probably be linked to healthy aging. Moreover, we identified key driver microbes responsible for such age-dependent network changes, which were further linked to altered metabolic functions of lipids, carbohydrates, and amino acids, as well as phenotypes in the microbial community. The current study thus demonstrates the lifelong age-dependent changes and their driver microbes in the primate gut microbiota, and provides new insights into their roles in the development and healthy aging of their hosts.     

Plant and Fungal Diversity in Gut Microbiota as Revealed by Molecular and Culture Investigations

Background

Few studies describing eukaryotic communities in the human gut microbiota have been published. The objective of this study was to investigate comprehensively the repertoire of plant and fungal species in the gut microbiota of an obese patient.

Methodology/Principal Findings

A stool specimen was collected from a 27-year-old Caucasian woman with a body mass index of 48.9 who was living in Marseille, France. Plant and fungal species were identified using a PCR-based method incorporating 25 primer pairs specific for each eukaryotic phylum and universal eukaryotic primers targeting 18S rRNA, internal transcribed spacer (ITS) and a chloroplast gene. The PCR products amplified using these primers were cloned and sequenced. Three different culture media were used to isolate fungi, and these cultured fungi were further identified by ITS sequencing. A total of 37 eukaryotic species were identified, including a Diatoms (Blastocystis sp.) species, 18 plant species from the Streptophyta phylum and 18 fungal species from the Ascomycota, Basidiomycota and Chytridiocomycota phyla. Cultures yielded 16 fungal species, while PCR-sequencing identified 7 fungal species. Of these 7 species of fungi, 5 were also identified by culture. Twenty-one eukaryotic species were discovered for the first time in human gut microbiota, including 8 fungi (Aspergillus flavipes, Beauveria bassiana, Isaria farinosa, Penicillium brevicompactum, Penicillium dipodomyicola, Penicillium camemberti, Climacocystis sp. and Malassezia restricta). Many fungal species apparently originated from food, as did 11 plant species. However, four plant species (Atractylodes japonica, Fibraurea tinctoria, Angelica anomala, Mitella nuda) are used as medicinal plants.

Conclusions/Significance

Investigating the eukaryotic components of gut microbiota may help us to understand their role in human health.     

Antibiotic Treatment Drives the Diversification of the Human Gut Resistome

Despite the documented antibiotic-induced disruption of the gut microbiota, the impact of antibiotic intake on strain-level dynamics, evolution of resistance genes, and factors influencing resistance dissemination potential remains poorly understood. To address this gap we analyzed public metagenomic datasets from 24 antibiotic treated subjects and controls, combined with an in-depth prospective functional study with two subjects investigating the bacterial community dynamics based on cultivation-dependent and independent methods. We observed that shortterm antibiotic treatment shifted and diversified the resistome composition, increased the average copy number of antibiotic resistance genes, and altered the dominant strain genotypes in an individual-specific manner. More than 30% of the resistance genes underwent strong differentiation at the single nucleotide level during antibiotic treatment. We found that the increased potential for horizontal gene transfer, due to antibiotic administration, was ～3-fold stronger in the differentiated resistance genes than the non-differentiated ones. This study highlights how antibiotic treatment has individualized impacts on the resistome and strain level composition, and drives the adaptive evolution of the gut microbiota.     

Classification of the Gut Microbiota of Patients in Intensive Care Units During Development of Sepsis and Septic Shock

The gut microbiota of intensive care unit (ICU) patients displays extreme dysbiosis associated with increased susceptibility to organ failure, sepsis, and septic shock. However, such dysbiosis is difficult to characterize owing to the high dimensional complexity of the gut microbiota. We tested whether the concept of enterotype can be applied to the gut microbiota of ICU patients to describe the dysbiosis. We collected 131 fecal samples from 64 ICU patients diagnosed with sepsis or septic shock and performed 16S rRNA gene sequencing to dissect their gut microbiota compositions. During the development of sepsis or septic shock and during various medical treatments, the ICU patients always exhibited two dysbiotic microbiota patterns, or ICU-enterotypes, which could not be explained by host properties such as age, sex, and body mass index, or external stressors such as infection site and antibiotic use. ICU-enterotype I (ICU E1) comprised predominantly Bacteroides and an unclassified genus of Enterobacteriaceae, while ICU-enterotype II (ICU E2) comprised predominantly Enterococcus. Among more critically ill patients with Acute Physiology and Chronic Health Evaluation II (APACHE II) scores > 18, septic shock was more likely to occur with ICU E1 (P = 0.041). Additionally, ICU E1 was correlated with high serum lactate levels (P = 0.007). Therefore, different patterns of dysbiosis were correlated with different clinical outcomes, suggesting that ICU-enterotypes should be diagnosed as independent clinical indices. Thus, the microbial-based human index classifier we propose is precise and effective for timely monitoring of ICU-enterotypes of individual patients. This work is a first step toward precision medicine for septic patients based on their gut microbiota profiles.     

Comparison of gut microbiota of healthy and diseased walking sticks,Phasmotaenia lanyuhensis

Research on gut microbiota of phytophagous insects has shown to be important for the physiological functions of insect hosts; however, little is known about the changes in gut microbiota when they are suffering from environmental stress or pathogen infections. During rearing of Phasmotaenia lanyuhensis (Phasmatodea: Phasmatidae), sluggish locomotion was usually followed by the death of the insect with a symptom of melanization in the front part of the abdomen. Therefore, the abnormal individuals were initially classified into moribund, light- and serious-symptom based on the level of abnormal physiological circumstances and melanization. The gut microbiota of these samples were further investigated by 16S metagenomic sequencing and the differences in bacterial abundance and structure of bacterial community were analyzed. A decrease in microbiota diversity was observed in the diseased P. lanyuhensis, with the abundance of phyla Proteobacteria and Firmicute relatively higher compared to those without symptom. Interestingly, principal component analysis based on the bacterial richness was correlated to the level of melanization symptom in the diseased P. lanyuhensis, suggested the change in bacterial microbiota involved in this abnormal circumstance. However, the factor that caused the initial alternation of microbiota remains to be identified. Additionally, the lack of bacterial diversity (i.e., absence of Meiothermus and Nubsella spp.) in P. lanyuhensis might reduce the fitness for surviving. This report provided the comprehensive microbiota analysis for P. lanyuhensis and concluded that either the relative abundance or the bacterial diversity of microbiota in the insect digestive system may influence the physiological functions of phytophagous insects.     

Considerations for Gut Microbiota and Probiotics in Patients with Diabetes Amidst the Covid-19 Pandemic: A Narrative Review

Objective: To review data implicating microbiota influences on Coronavirus Disease 2019 (COVID-19) in patients with diabetes.Methods: Primary literature review included topics: “COVID-19,” “SARS,” “MERS,” “gut micro-biota,” “probiotics,” “immune system,” “ACE2,” and “metformin.”Results: Diabetes was prevalent (~11%) among COVID-19 patients and associated with increased mortality (about 3-fold) compared to patients without diabetes. COVID-19 could be associated with worsening diabetes control and new diabetes diagnosis that could be linked to high expression of angiotensin-converting enzyme 2 (ACE2) receptors (coronavirus point of entry into the host) in the endocrine pancreas. A pre-existing gut microbiota imbalance (dysbiosis) could contribute to COVID-19–related complications in patients with diabetes. The COVID-19 virus was found in fecal samples (~55%), persisted for about 5 weeks, and could be associated with diarrhea, suggesting a role for gut dysbiosis. ACE2 expressed on enterocytes and colonocytes could serve as an alternative route for acquiring COVID-19. Experimental models proposed some probiotics, including Lactobacillus casei, L. plantarum, and L. salivarius, as vectors for delivering or enhancing efficacy of anti-coronavirus vaccines. These Lactobacillus probiotics were also beneficial for diabetes. The potential mechanisms for interconnections between coronavirus, diabetes, and gut microbiota could be related to the immune system, ACE2 pathway, and metformin treatment. There were suggestions but no proof supporting probiotics benefits for COVID-19 infection.Conclusion: The data suggested that the host environment including the gut microbiota could play a role for COVID-19 in patients with diabetes. It is a challenge to the scientific community to investigate the beneficial potential of the gut microbiota for strengthening host defense against coronavirus in patients with diabetes.     

The inconstant gut microbiota of Drosophila species revealed by 16S rRNA gene analysis

The gut microorganisms in some animals are reported to include a core microbiota of consistently associated bacteria that is ecologically distinctive and may have coevolved with the host. The core microbiota is promoted by positive interactions among bacteria, favoring shared persistence; its retention over evolutionary timescales is evident as congruence between host phylogeny and bacterial community composition. This study applied multiple analyses to investigate variation in the composition of gut microbiota in drosophilid flies. First, the prevalence of five previously described gut bacteria (Acetobacter and Lactobacillus species) in individual flies of 21 strains (10 Drosophila species) were determined. Most bacteria were not present in all individuals of most strains, and bacterial species pairs co-occurred in individual flies less frequently than predicted by chance, contrary to expectations of a core microbiota. A complementary pyrosequencing analysis of 16S rRNA gene amplicons from the gut microbiota of 11 Drosophila species identified 209 bacterial operational taxonomic units (OTUs), with near-saturating sampling of sequences, but none of the OTUs was common to all host species. Furthermore, in both of two independent sets of Drosophila species, the gut bacterial community composition was not congruent with host phylogeny. The final analysis identified no common OTUs across three wild and four laboratory samples of D. melanogaster. Our results yielded no consistent evidence for a core microbiota in Drosophila. We conclude that the taxonomic composition of gut microbiota varies widely within and among Drosophila populations and species. This is reminiscent of the patterns of bacterial composition in guts of some other animals, including humans.     

不同地区的东亚飞蝗肠道微生物多样性分析

【目的】鉴于肠道微生物在昆虫环境适应过程中发挥重要作用,探索中国不同地区分布的东亚飞蝗肠道微生物多样性情况。【方法】本文利用Illumina NovaSeq测序平台对中国4个代表性蝗区的东亚飞蝗(Locusta migratoria manilensis Meyen)肠道微生物进行16S rRNA基因测序和分析,探究其多样性。【结果】分布区域、发育时期和性别对东亚飞蝗肠道微生物结构均影响明显,其中分布区域的影响最为显著,其次为性别和发育时期。多样性分析发现,采自广东省清远市和河北省沧州市的东亚飞蝗肠道微生物多样性差异性较大,所选取的8个环境因子中平均气温和降水量可影响东亚飞蝗的肠道菌群多样性。【结论】研究结果从共生微生物和环境因素角度解析了东亚飞蝗的环境适应性,为研制地理溯源技术和开发微生物制剂提供了科学依据。