Correlation between faecal microbial taxa and ulcerative colitis in different phases of disease activity in a north Indian cohort

Objective: A link between gut microbiota and Ulcerative Colitis (UC) has been established in several studies. However, a few studies have examined specific changes in microbiota associated with different phases of disease activity in UC. In this study, we investigated phenotypic variability underlying genetically distinct north Indian (NI) UC patients by identifying differentially abundant taxa between (i) UC patients and healthy controls and (ii) different disease phases of disease activity. Design: 16S rRNA (V3,V4) sequencing of 105 patients with UC [newly diagnosed (n=14); patients in remission (n=36) and active disease (relapse, n=55)]; and 36 healthy controls was performed. The faecal microbiota composition in different phases of UC disease activity and healthy controls was analysed. Results: Lower gut microbial diversity; enrichment of lactate-producing bacteria namely Streptococcus, Bifidobacterium and Lactobacillus; and depletion of butyrate-producing bacteria (e.g., Lachnospiraceae and Ruminococcaceae), was observed among UC patients. Subgroup analysis revealed differential abundance of Escherichia-Shigella, Streptococcus, Enterococcus and Faecalibacterium in newly diagnosed UC patients. No discrete microbial features were observed between patients in remission and those with active disease. Co-occurrence network analysis revealed a mutualistic association between opportunistic pathogens and Bifidobacterium and Lactobacillus and antagonistic relationship with butyrate-producers. Conclusion: This first faecal microbiome study elucidated dysanaerobiosis; loss of short chain fatty acid producers and enrichment of inflammation associated microbes; population specific differential microbial genera; and microbial signature for early dysbiosis, among NI UC cohort.

Exploring bycatch diversity of organisms in whole genome sequencing of Erebidae moths (Lepidoptera)

Models estimate that up to 80% of all butterfly and moth species host vertically transmitted endosymbiotic microorganisms, which can affect the host fitness, metabolism, reproduction, population dynamics, and genetic diversity, among others. The supporting empirical data are however currently highly biased towards the generally more colourful butterflies, and include less information about moths. Additionally, studies of symbiotic partners of Lepidoptera predominantly focus on the common bacterium Wolbachia pipientis, while infections by other inherited microbial partners have more rarely been investigated. Here, we mine the whole genome sequence data of 47 species of Erebidae moths, with the aims to both inform on the diversity of symbionts potentially associated with this Lepidoptera group, and discuss the potential of metagenomic approaches to inform on host associated microbiome diversity. Based on the result of Kraken2 and MetaPhlAn2 analyses, we found clear evidence of the presence of Wolbachia in four species. Our result also suggests the presence of three other bacterial symbionts (Burkholderia spp., Sodalis spp. and Arsenophonus spp.) in three other moth species. Additionally, we recovered genomic material from bracovirus in about half of our samples. The detection of the latter, usually found in mutualistic association to braconid parasitoid wasps, may inform on host-parasite interactions that take place in the natural habitat of the Erebidae moths, suggesting either contamination with material from species of the host community network, or horizontal transfer of members of the microbiome between interacting species.

Thermal stable and proteinase-K resistant insecticidal toxins produced by Photorhabdus luminescens

Photorhabdus is lives in a mutualistic association with nematodes from the family Heterorhabditis. Bacteria of the Photorhabdus can survive independently and cause toxicity in a larger variety of insects. In the present study, insecticidal activity of non-portentous heat-stable metabolites of Photorhabdus luminescens was evaluated against Galleria mellonella. For this purpose, the culture extract of P. luminescens was injected into the G. mellonella larvae, which killed almost 90% of larvae within 48 h. The extract showed 100% insecticidal activity after heat treatment of 70 C for 30 min and even 60% and 40% activity lasted at 80 C and 90 C respectively. The extract also showed a high degree of thermal stability and was 100% actives after 60 min at 70 C. In addition, insecticidal activity was preserved up to 100% after all proteinase-K treatments (0 ?g/mL to 50 ?g/mL). The results revealed that the extracts were non-portentous and showed high thermal resistance and stability. Keywords: Photorhabdus, insecticidal activity, toxins, heat stable non-proteinaceous

Exploring bycatch diversity of organisms in whole genome sequencing of Erebidae moths (Lepidoptera)

Models estimate that up to 80% of all butterfly and moth species host vertically transmitted endosymbiotic microorganisms, which can affect the host fitness, metabolism, reproduction, population dynamics, and genetic diversity, among others. The supporting empirical data are however currently highly biased towards the generally more colourful butterflies, and include less information about moths. Additionally, studies of symbiotic partners of Lepidoptera predominantly focus on the common bacterium Wolbachia pipientis, while infections by other inherited microbial partners have more rarely been investigated. Here, we mine the whole genome sequence data of 47 species of Erebidae moths, with the aims to both inform on the diversity of symbionts potentially associated with this Lepidoptera group, and discuss the potential of metagenomic approaches to inform on their associated microbiome diversity. Based on the result of Kraken2 and MetaPhlAn2 analyses, we found clear evidence of the presence of Wolbachia in four species. Our result also suggests the presence of three other bacterial symbionts (Burkholderia spp., Sodalis spp. and Arsenophonus spp.), in three other moth species. Additionally, we recovered genomic material from bracovirus in about half of our samples. The detection of the latter, usually found in mutualistic association to braconid parasitoid wasps, may inform on host-parasite interactions that take place in the natural habitat of the Erebidae moths, suggesting either contamination with material from species of the host community network, or horizontal transfer of members of the microbiome between interacting species.

A study on Xenorhabdus and Photorhabdus isolates from Northeastern Thailand: Identification, antibacterial activity, and association with entomopathogenic nematode hosts

Xenorhabdus and Photorhabdus are gram negative bacteria that can produce several secondary metabolites, including antimicrobial compounds. They have a symbiotic association with entomopathogenic nematodes (EPNs). The aim of this study was to isolate and identify Xenorhabdus and Photorhabdus species and their associated nematode symbionts from Northeastern region of Thailand. We also evaluated the antibacterial activity of these symbiotic bacteria. The recovery rate of EPNs was 7.82% (113/1445). A total of 62 Xenorhabdus and 51 Photorhabdus strains were isolated from the EPNs. Based on recA sequencing and phylogeny, Xenorhabdus isolates were identified as X. stockiae (n = 60), X. indica (n = 1) and X. eapokensis (n = 1). Photorhabdus isolates were identified as P. luminescens subsp. akhurstii (n = 29), P. luminescens subsp. hainanensis (n = 18), P. luminescens subsp. laumondii (n = 2), and P. asymbiotica subsp. australis (n = 2). The EPNs based on 28S rDNA and internal transcribed spacer (ITS) analysis were identified as Steinernema surkhetense (n = 35), S. sangi (n = 1), unidentified Steinernema (n = 1), Heterorhabditis indica (n = 39), H. baujardi (n = 1), and Heterorhabditis sp. SGmg3 (n = 3). Antibacterial activity showed that X. stockiae (bMSK7.5_TH) extract inhibited several antibiotic-resistant bacterial strains. To the best of our knowledge, this is the first report on mutualistic association between P. luminescens subsp. laumondii and Heterorhabditis sp. SGmg3. This study could act as a platform for future studies focusing on the discovery of novel antimicrobial compounds from these bacterial isolates.

Natural history notes on worker size, colony size, and nest structure of Azteca muelleri Emery, 1893 (Hymenoptera: Formicidae) in Cecropia glaziovii (Rosales: Urticaceae) from the Atlantic Forest

Mutualistic association between Azteca Forel, 1878 ants and Cecropia Loefl. plants are one of the most studied interactions in Neotropics, however, natural history studies of Azteca species still poorly investigated due to the great effort required to conduct detailed descriptive studies. Here, we describe biological aspects of Azteca muelleri Emery, 1893 nesting in Cecropia glaziovii Snethl. in a fragment of Atlantic Forest, addressing (a) colony size; (b) nest distribution on the tree; and (c) worker and queen morphometrics. We collected two C. glaziovii saplings and counted characteristics of the nests and plants. We randomly selected 140 workers to measure and to determine whether intraspecific polymorphism occurs. Workers, immatures, and mealybugs were present in all hollow internodes of plant, and a queen was found. We found isometric morphological variation in A. muelleri. Our study provides new data to understand the biology of A. muelleri nesting in C. glaziovii, one of the most species-rich genera of arboreal ants known for the neotropics.

Host apoplastic cysteine protease activity is suppressed during the mutualistic association of Lolium perenne and Epichloë festucae

Plants secrete various defence-related proteins into the apoplast, including proteases. Papain-like cysteine proteases (PLCPs) are central components of the plant immune system. To overcome plant immunity and successfully colonize their hosts, several plant pathogens secrete effector proteins inhibiting plant PLCPs. We hypothesized that not only pathogens, but also mutualistic microorganisms interfere with PLCP-meditated plant defences to maintain endophytic colonization with their hosts. Epichloë festucae forms mutualistic associations with cool season grasses and produces a range of secondary metabolites that protect the host against herbivores. In this study, we performed a genome-wide identification of Lolium perenne PLCPs, analysed their evolutionary relationship, and classified them into nine PLCP subfamilies. Using activity-based protein profiling, we identified four active PLCPs in the apoplast of L. perenne leaves that are inhibited during endophyte interactions. We characterized the L. perenne cystatin LpCys1 for its inhibitory capacity against ryegrass PLCPs. LpCys1 abundance is not altered during the mutualistic interaction and it mainly inhibits LpCP2. However, since the activity of other L. perenne PLCPs is not sensitive to LpCys1, we propose that additional inhibitors, likely of fungal origin, are involved in the suppression of apoplastic PLCPs during E. festucae infection.

Antifungals, arthropods and antifungal resistance prevention: lessons from ecological interactions

Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods’ armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu.

Molecular Evidence of Rickettsia felis in Phereoeca sp.

Rickettsia felis is an obligate intracellular bacterium capable of infecting ticks, fleas, lice, and other arthropods. This bacterium is classified as a member of the Transitional Group (TRG) Rickettsia. It is known the evidence of R. felis mutualistic and obligatory relationship with some eukaryote organisms. However, there aren’t scientific accounts of R. felis and moths of the order Lepidoptera association. The current work reports the first identification of the bacteria R. felis in Phereoeca sp. For that, a polymerase chain reaction (PCR) assay using gltA, ompA, and ompB genes was used. The nucleotide sequences showed 100% of identity with other Rickettsia felis sequences. The genus-level identification of the moth larvae was performed by morphological taxonomic keys and PCR analysis of the cytochrome oxidase I (COI) gene. The nucleotide sequenced showed 94.94% similarity with the species Phereoeca praecox. However, with the low number of sequences deposited in the databases, the species was classified as Phereoeca sp. The results suggest that R. felis may develop in an organism without blood-feeding behavior (Lepidoptera), as it has been demonstrated for booklice (Psocoptera). Further investigation is necessary in order to confirm pathogenic or mutualistic association with moths.

Epichloë festucae in mutualistic association with Lolium perenne suppresses host apoplastic cysteine protease activity

Plants secrete various defence-related proteins into the apoplast, including proteases. Papain-like cysteine proteases (PLCPs) are central components of the plant immune system. To overcome plant immunity and successfully colonise their hosts, several plant pathogens secrete effector proteins inhibiting plant PLCPs. We hypothesized that not only pathogens but also mutualistic microorganisms interfere with PLCP-meditated plant defences to maintain endophytic colonisation with their hosts. Epichloë festucae forms mutualist associations with cool season grasses and produces a range of secondary metabolites that protect the host against herbivores. In this study, we performed a genome wide identification of Lolium perenne PLCPs, analysed their evolutionary relationship and classified them into nine PLCP subfamilies. Using activity-based protein profiling, we identified four active PLCPs in the apoplast of L. perenne leaves that are inhibited during endophyte interactions. We characterized the L. perenne cystatin LpCys1 for its inhibitory capacity against ryegrass PLCPs. LpCys1 inhibits LpCP2, indicating that LpCys1 might play a role in the suppression of PLCP activity during the interaction with E. festucae. However, since the activity of other L. perenne PLCPs is not sensitive to LpCys1 we propose that additional inhibitors are involved in the suppression of apoplastic PLCPs during E. festucae infection.