Ketamine interactions with gut-microbiota in rats: relevance to its antidepressant and anti-inflammatory properties

Background

Appreciable evidence suggest that dysbiosis in microbiota, reflected in gut microbial imbalance plays a key role in the pathogenesis of neuropsychiatric disorders including depression and inflammatory diseases. Recently, the antidepressant properties of ketamine have gained prominence due to its fast and long lasting effects. Additional uses for ketamine in inflammatory disorders such as irritable bowel syndrome have been suggested. However, ketamine’s exact mechanism of action and potential effects on microbiome is not known. Here, we examined the effects of low dose ketamine, known to induce antidepressant effects, on stool microbiome profile in adult male Wistar rats. Animals (5/group) were injected intraperitoneally with ketamine (2.5?mg/kg) or saline, daily for 7?days and sacrificed on day 8 when intestinal stools were collected and stored at ??80?°C. DNA was extracted from the samples and the 16?S rRNA gene-based microbiota analysis was performed using 16S Metagenomics application.

Results

At genus–level, ketamine strikingly amplified Lactobacillus, Turicibacter and Sarcina by 3.3, 26 and 42 fold, respectively. Conversely, opportunistic pathogens Mucispirillum and Ruminococcus were reduced by approximately 2.6 and 26 fold, respectively, in ketamine group. Low levels of Lactobacillus and Turicibacter are associated with various disorders including depression and administration of certain species of Lactobacillus ameliorates depressive-like behavior in animal models. Hence, some of the antidepressant effects of ketamine might be mediated through its interaction with these gut bacteria. Additionally, high level of Ruminococcus is positively associated with the severity of irritable bowel syndrome (IBS), and some species of Mucispirillum have been associated with intestinal inflammation. Indirect evidence of anti-inflammatory role of Sarcina has been documented. Hence, some of the anti-inflammatory effects of ketamine and its usefulness in specific inflammatory diseases including IBS may be mediated through its interaction with these latter bacteria.

Conclusion

Our data suggest that at least some of the antidepressant and anti-inflammatory effects of daily ketamine treatment for 7?days may be mediated via its interaction with specific gut bacteria. These findings further validate the usefulness of microbiome as a target for therapeutic intervention and call for more detailed investigation of microbiome interaction with central mediators of mood and/or inflammatory disorders.

     

Comparative bacterial survey in the gut of lepidopteran insects with different bionetwork

Insect gut is an untapped reservoir persist numerous unidentified gene responsible for the digestion of complex food material into a simpler nutrients, this activity of gut was enhanced by the microbial interaction. Insect gut-microbe interaction encodes beneficial activity to its host in several aspects, to illuminate the tactic of the interaction this study was framed and worked out in two insect species such as Spodoptera litura and Bombyx mori. The present study surveyed the comparative diversity of microbial population in the gut of a field pest Spodoptera litura and domesticated insect silkworm Bombyx mori at their active feeding larval stage. Both culture dependent and culture independent approaches exposed the dominance of Enterobacteriacae family and with majority of proteobacteria and firmicutes residing in the gut of both Spodoptera litura and Bombyx mori. Especially, the Enterococcus mundtii is a predominant affiliate in both processes of both insects.     

Review of the species of the genus <Emphasis Type="Italic">Leptomastidea</Emphasis> Mercet, 1916 (Hymenoptera,Encyrtidae) of the World,with description of a new species from Montenegro and with separation of a new genus from Turkmenia

The review contains a key to females of the species of the genus Leptomastidea Mercet, 1926 of the World fauna and annotated synopsis of 25 species with data on their distribution, hosts, plants, and use in biological control [for L. abnormis (Girault)]. L. ljubodragi sp. n. is described from Montenegro. A new genus Proleptomastidea gen. n. is erected for Leptanusia enigmatica Trjapitzin, 1971 from Turkmenistan. Leptanusia turkmenica Myartseva, 1978 is transferred to the genus Anagyrus Howard, 1896 and, thus, a new combination, Anagyrus turkmenicus (Myartseva, 1978), comb. n., is formed.     

Ethnicity influences gut metabolites and microbiota of the tribes of Assam,India

Introduction

The human gut microbes and their metabolites are involved in multiple host metabolic pathways. Dysbiosis in the gut microbiota and altered metabolite profiles were reported in diseased state. In a region like Assam, where 12.4% of the populations are tribal population, evaluating the influence of ethnicity on gut microbiota and metabolites has become important to further differentiate it from the diseased state.

Objective

To study the influence of ethnicity on fecal metabolite profile and their association with the gut microbiota composition.

Methods

In this study, we determined the untargeted fecal metabolites from five ethnic groups of Assam (Tai-Aiton, Bodo, Karbi, Tea-tribe and Tai-Phake) using GC–MS and compared them among the tribes for common and unique metabolites. Metabolites of microbial origin were related with the available metagenomic data on gut bacterial profiles of the same ethnic groups and functional analysis were carried out based on HMDB.

Results

The core fecal metabolite profile of the Tea-tribe contained aniline, benzoate and acetaldehyde. PLS-DA based on the metabolites suggested that the individuals grouped based on their ethnicity. PCA plot of the data on bacterial abundance at the level of genus indicated clustering of individuals based on ethnicity. Positive correlations were observed between propionic acid and the genus Clostridium (R?=?0.43 and p?=?0.03), butyric acid and the genus Lactobacillus (R?=?0.45 and p?=?0.024), acetic acid and the genus Bacteroides (R?=?0.63 and p?=?0.001) and methane and the genus Escherichia (R?=?0.58 and p?=?0.002).

Conclusion

Results of this study indicated that ethnicity influences both gut bacterial profile and their metabolites.

     

<Emphasis Type="Italic">Basidiophora delawarensis</Emphasis>, a new downy mildew species infecting cultivated goldenrod (<Emphasis Type="Italic">Solidago sphacelata</Emphasis>) in the USA

Species in the genus Basidiophora (Oomycota, Peronosporales) are pathogens causing downy mildew disease on several closely related plant hosts in the family Asteraceae, including the genera Conyza, Erigeron, Solidago, and Symphyotrichum. Despite their widespread occurrence, little is known about the diversity, biology, and economic impact of downy mildew pathogens of ornamental or wild plants in the Asteraceae. In June 2017, Solidago sphacelata plants of the cultivar ‘Golden Fleece’ were found in the state of Delaware, USA, showing typical symptoms of downy mildew disease. Initial morphological observations indicated the specimen belonged to the genus Basidiophora. Phylogenetic analysis of a sequence matrix of the partial cox2 mitochondrial gene using Bayesian and maximum likelihood methods showed that the Basidiophora isolate from S. sphacelata represents an undescribed species that is here described as B. delawarensis. This new species constitutes the third accepted species in the genus Basidiophora and can be distinguished from other Basidiophora species by differences in size of sporangia and sporangiophores and nucleotide sequence divergence. This new species poses a potential threat to its host, warranting close monitoring and the implementation of disease management programs.     

Diet,physical activity and screen time but not body mass index are associated with the gut microbiome of a diverse cohort of college students living in university housing: a cross-sectional study

Background

Modifiable lifestyle factors (e.g. dietary intake and physical activity) are important contributors to weight gain during college. The purpose of this study was to evaluate whether associations exist between body mass index, physical activity, screen time, dietary consumption (fat, protein, carbohydrates, and fiber), and gut microbial diversity during the first year of college. Racially/ethnically diverse college students (n?=?82; 61.0% non-white) at a large Southwestern university completed self-reported physical activity and 24-h recall dietary assessments, height and weight measurements, and provided one fecal sample for gut microbiome analysis. Fecal microbial community composition was assessed with Illumina MiSeq next-generation sequencing of PCR amplified 16S rRNA genes. Post-hoc analyses compared microbial diversity by groups of high and low physical activity and fiber intake using QIIME and LEfSe bioinformatics software.

Results

No statistically significant differences were observed between body mass index and gut microbiome abundance and diversity. Median daily consumption of dietary fiber was 11.2 (7.6, 14.9) g/d, while the median self-reported moderate-to-vigorous physical activity (MVPA) was 55.7 (27.9, 79.3) min/d and screen time 195.0 (195.0, 315.0) min/d. Microbial analysis by LEfSe identified Paraprevotellaceae, Lachnospiraceae, and Lachnospira as important phylotypes in college students reporting greater MVPA, while Enterobacteriaceae and Enterobacteriales were more enriched among students reporting less MVPA (p?<?0.05). Barnesiellaceae, Alphaproteobacteria, and Ruminococcus were more abundant taxa among those consuming less than the median fiber intake (p?<?0.05). Post-hoc analyses comparing weighted UniFrac distance metrics based on combined categories of high and low MVPA and fiber revealed that clustering distances between members of the high MVPA-low fiber group were significantly smaller when compared to distances between members of all other MVPA-fiber groups (p?<?0.0001).

Conclusions

Habitual fiber consumption and MVPA behaviors help explain the differential abundance of specific microbial taxa and overall gut microbial diversity differences in first-year college students.

     

Characterisation of members of the <Emphasis Type="Italic">Fusarium incarnatum</Emphasis>-<Emphasis Type="Italic">equiseti</Emphasis> species complex from undisturbed soils in South Africa

The genus Fusarium hosts a large number of economically significant phytopathogens with a global distribution. Surprisingly, only a limited number of studies have tried to identify the natural distribution of members of this genus in undisturbed soils. Members of the Fusarium incarnatum-equiseti species complex (FIESC) are increasingly associated with plant disease, and human and animal health problems. Recently, an outbreak of kikuyu poisoning of cattle was attributed to the F. incarnatum-equiseti species complex. Thus, it is of importance to identify the natural distribution of members of the FIESC from the environment. The aim of this study was to use the phylogenetic signal within the TEF 1α gene region to characterise 54 F. incarnatum-equiseti isolates obtained from undisturbed soils from the grassland biome of South Africa. These isolates were further compared with members of the FIESC previously associated with kikuyu poisoning of cattle. The phylogenetic analysis indicated a high level of variation within this species complex. Several members were closely related to isolates implicated in the death of cattle from infected kikuyu grass.     

New data on trophic relations between eulophid parasitic wasps (Hymenoptera,Eulophidae) and lepidopterans in Ul’yanovsk Province

Twenty seven species of the family Eulophidae were reared from 20 new lepidopteran hosts in Ul’yanovsk Province. Among newly revealed host-parasitoid associations, 27, 9, 3, and 3 are those with Phyllonorycter (Gracillariidae), Stigmella and single species of Ectoedemia (Nepticulidae), Yponomeuta (Yponomeutidae), and Tischeria (Tischeriidae), respectively. Ectoparasitoids prevailed among parasitoids of the genus Phyllonorycter, and endoparasitoids, among parasitoids of the genera Stigmella and Tischeria.     

Divergence in selection of host species and plant parts among populations of a phytophagous insect

The diversification of phytophagous insects is often attributed to diverging processes of host plant specialization onto different, often closely related, host plants. Some insect clades have diversified by specializing not only on different plant species but also on different plant parts of the same hosts. This is the case in Greya moths (Prodoxidae) where both Greya obscura and G. politella are tightly linked to host plants of the genus Lithophragma (Saxifragaceae). We assess how these species differ in their choice of plants and use of plant parts. Previous work showed that strong local host specialization in G. politella is mediated by floral scent variation among Lithophragma species. Here, we identify geographic variation in host plant use in the close relative G. obscura, relate the emerging patterns to previous studies of geographic variation in host use in G. politella and evaluate potential processes underlying the variation among and within species. First, we show that G. obscura also uses floral chemistry to locate hosts but that additional plant cues must be involved in deciding whether to oviposit on a plant, because females did not discriminate against chemically different host species in no-choice trials. We also found that, although all known populations of G. politella oviposit only in flowers, all G. obscura populations examined here distributed their eggs among both floral and scape tissues both in the field and in laboratory experiments. The distribution of eggs among plant parts, however, varied among moth populations, and also depended on the Lithophragma species they attacked. Together, these results show the potential for phytophagous insect species and populations to diverge in use of plant parts as part of the process of speciation and adaptation. These two layers of specialization enhance the potential for subsequent diversification in phytophagous insect lineages.     

Core gut microbiota in Jinhua pigs and its correlation with strain,farm and weaning age

Gut microbial diversity and the core microbiota of the Jinhua pig, which is a traditional, slow-growing Chinese breed with a high body-fat content, were examined from a total of 105 fecal samples collected from 6 groups of pigs at 3 weaning ages that originated from 2 strains and were raised on 3 different pig farms. The bacterial community was analyzed following high-throughput pyrosequencing of 16S rRNA genes, and the fecal concentrations of short-chain fatty acids (SCFAs) were measured by gas chromatograph. Our results showed that Firmicutes and Bacteroidetes were the dominant phyla, and Lactobacillus, Streptococcus, Clostridium, SMB53, and Bifidobacterium were the most abundant genera. Fifteen predominant genera present in every Jinhua pig sample constituted a phylogenetic core microbiota and included the probiotics Lactobacillus and Bifidobacterium, and the SCFA-producing bacteria Clostridium, Prevotella, Bacteroides, Coprococcus, Roseburia, Ruminococcus, Blautia, and Butyricicoccus. Comparisons of the microbiota compositions and SCFA concentrations across the 6 groups of pigs demonstrated that genetic background and weaning age affected the structure of the gut microbiota more significantly than the farm. The relative abundance of the core genera in the pigs, including Lactobacillus, Clostridium, Prevotella, Bacteroides, Roseburia, Ruminococcus, Blautia, and Butyricicoccus varied dramatically in pigs among the 2 origins and 3 weaning ages, while Oscillospira, Megasphaera, Parabacteroides, and Corynebacterium differed among pigs from different farms. Interestingly, there was a more significant influence of strain and weaning age than of rearing farm on the SCFA concentrations. Therefore, strain and weaning age appear to be the more important factors shaping the intestinal microbiome of pigs.     

A Review of the Encyrtid-Wasp Genus <Emphasis Type="Italic">Zaplatycerus</Emphasis> Timberlake, 1925 (Hymenoptera,Chalcidoidea: Encyrtidae) of the World Fauna,Parasitoids of Mealybugs (Hemiptera,Pseudococcidae)

The article provides information about the genus Zaplatycerus Timberlake, 1925, a key to the females of its 16 species of the world fauna, and their synopsis with data on the distribution and hosts. Neoplatycerus tshernyshevi Trjapitzin, 2011 from Australia is transferred to Zaplatycerus as Z. tshernyshevi (Trjapitzin, 2011), comb. n.Neoplatycerus tshernyshevi Trjapitzin, 2013 is synonymized under Z. tshernyshevi (Trjapitzin, 2011), syn. n.     

Comparative analysis of the gut microbiota in distinct statin response patients in East China

Statin response shows great interindividual variations. Recently, emerging studies have shown that gut microbiota is linked to therapeutic responses to drugs, including statins. However, the association between the gut bacteria composition and statin response is still unclear. In this study, gut microbiota of 202 hyperlipidemic patients with statin sensitive (SS) response and statin resistant (SR) response in East China were investigated by high throughput sequencing to compare the gut bacteria composition and biodiversity in distinct statin response patients. Higher biodiversity was detected in Group SS than Group SR. Specifically, group SS showed significantly increased proportion of genera Lactobacillus (P = 0.001), Eubacterium (P = 0.004), Faecalibacterium (P = 0.005), and Bifidobacterium (P = 0.002) and decreased proportion of genus Clostridium (P = 0.001) compared to Group SR. The results indicated that higher gut biodiversity was associated with statin sensitive response. The increased genera Lactobacillus, Eubacterium, Faecalibacterium, Bifidobacterium, and decreased genus Clostridium in patient gut microbiota may predict patient's statin response, and hence may guide statin dosage adjustments.     

The only known white blister rust on a basal angiosperm is a member of the genus <Emphasis Type="Italic">Albugo</Emphasis>

Rare pathogens on unusual hosts are often providing valuable insight into the evolution of the pathogen group concerned, but it is often challenging to obtain sequence data for these, as because only very few, often decades-old specimens are available. One such example is Albugo tropica, the white blister pathogen of a basal angiosperm in the genus Peperomia (Piperaceae). For this species, only two, more than 70 and over 120-year-old collections available. Here, sequence data for A. tropica are reported and phylogenetic reconstructions reveal it as the sister group to all other white blister rusts of the genus Albugo. Its isolated position is also reflected by several morphological differences to the other species of the genus, such as very thin-walled sporangia and almost smooth oospores. The isolated phylogenetic position of the pathogen and its host might indicate that it is a relict species trapped on its host. The sister-group relationship to all members of the genus Albugo s.str., which have been investigated using molecular phylogenetics, hints at the possibility, that Albugo might have originated in South America or Gondwana and has later radiated in the holarctic on members of the Brassicales.     

The genus <Emphasis Type="Italic">Diaporthe</Emphasis>: a rich source of diverse and bioactive metabolites

The genus Diaporthe (asexual state: Phomopsis) comprises pathogenic, endophytic and saprobic species with both temperate and tropical distributions. Although species of Diaporthe have in the past chiefly been distinguished based on host association, studies have confirmed several taxa to have wide host ranges, suggesting that they move freely between hosts, frequently co-colonizing diseased or dead tissue, while some species are known to be host-specific. They are also very frequently isolated as endophytes of seed plants. Due to their importance as plant pathogens, the genus has been thoroughly investigated for secondary metabolites, including during screening programs aimed at the discovery of novel bioactive natural products, but the respective information has never been compiled. Therefore, we have examined the relevant literature to explore and highlight the major classes of metabolites of Diaporthe and their Phomopsis conidial states. These fungi predominantly produce a large number of polyketides, but cytochalasins and other types of commonly encountered fungal secondary metabolites are also predominant in some species. Interestingly, not a single metabolite which is also known from the host plant has ever been isolated as a major component from an endophytic Diaporthe strain, despite the fact that many of the recent studies were targeting endophytic fungi of medicinal plants.     

Alterations in gut bacterial and fungal microbiomes are associated with bacterial Keratitis,an inflammatory disease of the human eye

Dysbiosis, or imbalance in the gut microbiome, has been implicated in auto-immune, inflammatory, neurological diseases as well as in cancers. More recently it has also been shown to be associated with ocular diseases. In the present study, the association of gut microbiome dysbiosis with bacterial Keratitis, an inflammatory eye disease which significantly contributes to corneal blindness, was investigated. Bacterial and fungal gut microbiomes were analysed using fecal samples of healthy controls (HC, n?=?21) and bacterial Keratitis patients (BK, n?=?19). An increase in abundance of several anti-inflammatory organisms including Dialister, Megasphaera, Faecalibacterium, Lachnospira, Ruminococcus and Mitsuokella and members of Firmicutes, Veillonellaceae, Ruminococcaceae and Lachnospiraceae was observed in HC compared to BK patients in the bacterial microbiome. In the fungal microbiome, a decrease in the abundance of Mortierella, Rhizopus, Kluyveromyces, Embellisia and Haematonectria and an increase in the abundance of pathogenic fungi Aspergillus and Malassezia were observed in BK patients compared to HC. In addition, heatmaps, PCoA plots and inferred functional profiles also indicated significant variations between the HC and BK microbiomes, which strongly suggest dysbiosis in the gut microbiome of BK patients. This is the first study demonstrating the association of gut microbiome with the pathophysiology of BK and thus supports the gut–eye axis hypothesis. Considering that Keratitis affects about 1 million people annually across the globe, the data could be the basis for developing alternate strategies for treatment like use of probiotics or fecal transplantation to restore the healthy microbiome as a treatment protocol for Keratitis.     

Host-dependent differences in measures of condition associated with <Emphasis Type="Italic">Anilocra</Emphasis> spp. parasitism in two coral reef fishes

Parasites account for over half of the biodiversity on coral reefs, yet their ecological impacts are poorly understood. Cymothoid isopods of the genus Anilocra are large, conspicuous ectoparasites of coral reef fishes. French grunt (Haemulon flavolineatum) and brown chromis (Chromis multilineata) are commonly infected by Anilocra spp. in the Caribbean. These fishes play a significant role in trophic connectivity through their foraging and activity patterns, and Anilocra spp. infection has been reported to influence the trophic interactions of some fishes. Yet, how these changes manifest physiologically has not been quantified. Thus to determine the energetic effects of Anilocra spp. on French grunt and brown chromis, the relationships between Anilocra spp. infection and condition factor, percent moisture in the muscle tissue, total muscle tissue calories, and gut content volume were examined. The results of these analyses revealed that A. haemuli-infected French grunt had greater percent moisture in the muscle tissue but similar condition scores, calorie values, and gut content volumes compared to uninfected conspecifics. By comparison, Anilocra chromis-infected brown chromis had reduced condition factor, but similar percent moisture in the muscle tissue and total muscle tissue calories, as compared to uninfected conspecifics. This study provides evidence that infection by parasites of the same genus and within the same localities can have differential effects on fish host species, such that generalizations about the effects of parasitism across and within genera should be made cautiously.     

Comparison of the pollen content on the body and in the gut of hoverflies (Diptera,Syrphidae)

We analyzed the pollen content in the gut and on the body of hoverflies (Diptera: Syrphidae), mostly from three genera (Eristalis, Syrphus s. l., and Sphaerophoria) that visited flowers of two jointly flowering species of Apiaceae with indistinguishable pollen (Anthriscus sylvestris and Aegopodium podagraria) and of Bunias orientalis (Brassicaceae). Pollen compositions depended on the plant from which the flies were collected rather than on the insect genus. At the same time, individual preferences of the studied flies to food plant species were confirmed. The pollen compositions in the gut and on the body were weakly correlated. Two possible reasons for such a weak correlation are discussed: individual differences in the fly feeding habits and different time of pollen preservation in the gut and on the body.     

<Emphasis Type="Italic">Neocosmocercella fisherae</Emphasis> n. sp. (Nematoda: Cosmocercidae), a parasite of the large intestine of <Emphasis Type="Italic">Phyllomedusa bicolor</Emphasis> (Boddaert) (Anura: Phyllomedusidae) from the Brazilian Amazon

Neocosmocercella fisherae n. sp. is the first nematode species found parasitising Phyllomedusa bicolor from the Brazilian Amazon Region. The new species has a triangular oral opening, with bi-lobed lips, and is distinguished from N. bakeri (triangular oral opening with simple lips), and from N. paraguayensis (hexagonal oral opening with bi-lobed lips). Additionally, the new species has ciliated cephalic papillae, which are absent in the other species of the genus. The reduced uterine sac and the presence of a single egg in the uterus in females are the main morphological characters that differentiate the new species from its congeners N. bakeri (8–10 eggs) and N. paraguayensis (10 eggs, based on the allotype). Additionally, the new species differs from the other two species of the genus by morphometric characters such as the size of spicules and gubernaculum in males and the vagina in females. Until now, phyllomedusid anurans are the only known hosts for the nematodes of this genus. The present work describes the third species of the genus and the first species of nematode parasitising P. bicolor.