Search Results (223)

Endometriosis is a chronic inflammatory condition affecting approximately 10% of women of reproductive age, characterized by pelvic pain, dysmenorrhea, and infertility. Emerging evidence suggests a potential link between gut microbiota dysbiosis and endometriosis pathogenesis, mediated through hormonal regulation, immune modulation, and systemic inflammation. Dienogest (DNG) is widely used for endometriosis management, but its effects on gut microbiota remain underexplored. This study investigates the impact of DNG on gut microbial composition in endometriosis patients, aiming to elucidate its therapeutic mechanisms beyond hormonal modulation. DNG therapy led to a significant reduction in the Bacillota/Bacteroidota ratio (p = 0.0421), driven by decreased Staphylococcus spp. (p = 0.0244) and increased commensal bacteria such as Lactobacillus spp. and Collinsella aerofaciens (p = 0.049). Species richness and alpha diversity indices showed a non-significant upward trend. Notably, C. aerofaciens, a butyrate producer linked to gut barrier integrity, was detected twice as frequently during therapy. The study also observed reductions in facultative anaerobes like Enterococcus spp. and a trend toward higher titers of beneficial Bacteroidota. This study provides the first evidence that DNG therapy modulates gut microbiota in endometriosis patients, favoring a composition associated with anti-inflammatory and barrier-protective effects. The observed shifts—reduced opportunistic pathogens and increased symbionts—suggest a novel mechanism for DNG’s efficacy, potentially involving the microbial regulation of estrogen metabolism and immune responses. Full article

Dysbiosis is a strategy to control insect pests through disrupting symbiotic bacteria essential for their life cycle. The olive fly, Bactrocera oleae, has been considered a suitable system for dysbiosis, as the insect is strictly dependent on its unique symbiont Candidatus Erwinia dacicola. Here, we review older and recent results from studies of the interaction of the symbiont and its host fly. We then discuss possible methods for disrupting the symbiosis as a means to control the fly. Specifically, we summarize studies using microscopy methods that have investigated in great detail the organs where the bacterium resides and it is always extracellular. Furthermore, we discuss how genome sequences of both host and bacterium can provide valuable resources for understanding the interaction and transcriptomic analyses that have revealed important insights that can be exploited for dysbiosis strategies. We also assess experiments where compounds have been tested against the symbiont. The hitherto limited efficacy in decreasing bacterial abundance suggests that novel molecules and/or new ways for the delivery of agents will be important for successful dysbiosis strategies. Finally, we discuss how gene drive methods could be implemented in olive fly control, though a number of hurdles would need to be overcome. Full article

Snails at hydrothermal vents rely on symbiotic bacteria for nutrition; however, the specifics of these associations in adapting to such extreme environments remain underexplored. This study investigated the community structure and metabolic potential of bacteria associated with two Indian Ocean vent snails, Chrysomallon squamiferum and Gigantopelta aegis. Using microscopic, phylogenetic, and metagenomic analyses, this study examines bacterial communities inhabiting the foot and gland tissues of these snails. G. aegis exhibited exceptionally low bacterial diversity (Shannon index 0.14–0.18), primarily Gammaproteobacteria (99.9%), including chemosynthetic sulfur-oxidizing Chromatiales using Calvin–Benson–Bassham cycle and methane-oxidizing Methylococcales in the glands. C. squamiferum hosted significantly more diverse symbionts (Shannon indices 1.32–4.60). Its black variety scales were dominated by Campylobacterota (67.01–80.98%), such as Sulfurovum, which perform sulfur/hydrogen oxidation via the reductive tricarboxylic acid cycle, with both Campylobacterota and Gammaproteobacteria prevalent in the glands. The white-scaled variety of C. squamiferum had less Campylobacterota but a higher diversity of heterotrophic bacteria, including Delta-/Alpha-Proteobacteria, Bacteroidetes, and Firmicutes (classified as Desulfobacterota, Pseudomomonadota, Bacteroidota, and Bacillota in GTDB taxonomy). In C. squamiferum, Gammaproteobacteria, including Chromatiales, Thiotrichales, and a novel order “Endothiobacterales,” were chemosynthetic, capable of oxidizing sulfur, hydrogen, or iron, and utilizing the Calvin–Benson–Bassham cycle for carbon fixation. Heterotrophic Delta- and Alpha-Proteobacteria, Bacteroidetes, and Firmicutes potentially utilize organic matter from protein, starch, collagen, amino acids, thereby contributing to the holobiont community and host nutrition accessibility. The results indicate that host species and intra-species variation, rather than the immediate habitat, might shape the symbiotic microbial communities, crucial for the snails’ adaptation to vent ecosystems. Full article

Bacterial symbionts play an important role in insect survival by contributing to key metabolic and defensive functions. While stingless bees are known to harbor diverse microbial communities, their core bacterial symbionts remain poorly characterized. In this study, we analyzed the gut microbiota of sixteen stingless bee species collected from different regions of Mexico using 16S rRNA gene sequencing on the Illumina^® MiSeq™ platform. Our results revealed that Proteobacteria, Firmicutes, and Actinobacteria are the most abundant bacterial phyla across species. Among the dominant genera, lactic acid bacteria, such as Lactobacillus spp., Bifidobacterium, and Fructobacillus spp., were the most prevalent. These bacteria are responsible for developing biochemical functions in metabolic processes like lactic fermentation and the biotransformation of complex organic compounds into molecules that are more easily assimilated by bees. This study offers a novel perspective on the diversity and predicted composition of gut microbiota in Mexican stingless bees. By highlighting differences in microbial communities among species with different feeding habits, our results emphasize the importance of preserving microbial biodiversity in these pollinators. Full article

Insects and their endosymbionts have a close mutualistic relationship. However, the precise nature of the bacterial endosymbiont-mediated interaction between host plants and whitefly Bemisia tabaci MEAM1 is still unclear. In the present study, six populations of Bemisia tabaci MEAM1 sharing the same genetic background were established by rearing insects for ten generations on different host plants, including poinsettia, cabbage, cotton, tomato, and tobacco, and an additional population was reared on cotton and treated with antibiotics. The physiological and nutritional traits of the insects were found to be dependent on the host plant on which they had been reared. Systematic analysis was conducted on the endosymbiont titers, the amino acid molecules and contents, as well as developmental and oviposition changes in the MEAM1 populations reared on each host plant tested. The results indicate that B. tabaci contained the primary symbiont Portiera and the secondary symbionts Hamiltonella and Rickettsia. In addition, the titer of endosymbiotic bacteria in females is higher than that in males. Among the MEAM1 populations reared on each host plant, the variation pattern of Portiera titer generally corresponded with changes in biological characteristics (body length, weight and fecundity) and AA contents. This suggests that changes in the amino acid contents and biological characteristics of different B. tabaci populations may be due to changes in the Portiera content and the differences in the nutrition of the host plants themselves. Our findings were further confirmed by the reduction in Portiera with antibiotic treatment. The amino acids, body size, body weight, and fecundity of B. tabaci were all reduced with the decrease in the Portiera titer after antibiotic treatment. In summary, our research revealed that host plants can affect the content of symbiotic bacteria, particularly Portiera, and subsequently affect the nutrition (i.e., the essential amino acids content) of host insects, thus changing their biological characteristics. Full article

Harmless crop-associated insect communities are a fundamental part of the agroecosystem. Their potential as a reservoir of natural enemies of pests has encouraged their conservation through the development of low-impact pest management programs. The brown marmorated stink bug, Halyomorpha halys, represents a serious threat to Italian hazelnut production. Laboratory and field experiments confirmed the susceptibility of this pest to the disruption of the obligated symbiotic interaction with gut bacteria, paving the way for the development of the symbiont-targeted control strategy. Here we present the results of a three-year field assessment of symbiont-targeted control in a hazelnut orchard in northwestern Italy. The use of a biocomplex to disrupt symbiont acquisition by H. halys nymphs was compared to the use of lambda-cyhalothrin insecticide. The effects on the local entomofauna were assessed, as were the trend of H. halys population and the damage caused by stink bugs to harvested hazelnuts. The insecticide consistently reduced the insect diversity in the field, while the anti-symbiont biocomplex had no effect. However, the control of the H. halys population and the stink bug-induced damage to hazelnuts varied over the years in the field plot submitted to the symbiont-targeted approach. Our results indicate that the symbiont-targeted control does not interfere with local insect communities. Key aspects for improving the effectiveness of this tactic are discussed. Full article

Ambrosia beetles have evolved specialized structures termed “mycangia”, which house and transport symbiotic microbes. Microbial partners include at least one obligate mutualistic filamentous fungus used as food for larvae and adults, and potentially secondary filamentous fungi, yeasts, and bacteria. Beetles in the genus Xyleborus possess paired pre-oral mycangial structures located within the head on either side of the mouth parts. Mycangia develop in pupae, with newly emerged adults acquiring partners from the environment. However, information concerning the cellular structure and function of Xyleborus mycangia remains limited. We show that in X. affinis, mycangia are lined with a layer of striated dense material, enclosing layers of insect epithelial cells, with diverse spine-like structures. Larger (5–10 μm) projections were concentrated within and near the entrance of mycangia, with smaller filaments (4–8 μm) within the mycangia itself. Rows of “eyelash” structures lined the inside of mycangia, with fungal cells free-floating or in close association with these projections. Serial sections revealed mandibular articulations, and mandibular, pharyngeal, and labial muscles, along with the mycangial entry/exit channel. Sheets of comb-like spines at the mycangial entrance and opposite the mycangia attached to the roof of the labrum or epipharynx may serve as an interlocking mechanism for opening/closing the mycangia and guiding fungal cells into entry/exit channels. Additionally, mandibular fibra (muscle tissue) potentially enervating and affecting the mechanism of mycangial functioning were noted. These data add crucial mechanistic detail to the model of pre-oral mycangia in Xyleborus beetles, their cellular structures, and how they house and dispense microbial symbionts. Full article

Different movement patterns are crucial behavioral motifs of plant organisms for reaching essential resources necessary for survival. This requires the accurate evaluation (interpretation) of information inputs regarding (i) abiotic factors such as gravity, light, and water; (ii) neighboring plants; (iii) various beneficial symbionts, including fungi and soil bacteria, as well as pests, which involve attack and defense strategies; and (iv) intraorganismic communication, including transcription, translation, immunity, repair, and epigenetic markings relevant to all regulation processes, finally outlined by a plethora of non-coding RNAs. The coordination of all steps and substeps in plant growth and development necessitates a complex organization of various levels of signaling processes within and between cells, tissues, organs, and organisms. Consequently, we can view a plant body as a coordinated entity that integrates these processes to thrive, representing a unique identity within its environmental niche. Full article

Insect symbionts and their metabolites are complex and diverse and are gradually becoming an important source of new medical materials. Some culturable symbionts from insects produce a variety of active compounds with medical potential. Among them, fatty acids, antibacterial peptides, polyene macrolides, alkaloids, and roseoflavin can inhibit the growth of human pathogenic bacteria and fungi; lipases, yeast killer toxins, reactive oxygen species, pyridines, polyethers, macrotetrolide nactins, and macrolides can kill human parasites; and peptides and polyketides can inhibit human tumors. However, due to difficulty in the culture of symbionts in vitro, difficulty in targeting bacteria to specific sites in the human body, the limited capability of symbionts to produce active metabolites in vitro, inconsistent clinical research results, adverse reactions on humans, and the development of antibiotic resistance, the application of insect symbionts and their metabolites in the medical field remains in its infancy. This paper summarizes the medical potential of insect symbionts and their metabolites and analyzes the status quo and existing problems with their medical application. Possible solutions to these problems are also proposed, with the aim of hastening the utilization of insect symbionts and their metabolites in the medical field. Full article

Bacterial extracellular vesicles (BEVs) produced by members of the intestinal microbiota can not only contribute to digestion but also mediate microbe–host cell communication via the transfer of functional biomolecules to mammalian host cells. An unresolved question is which host factors and conditions influence BEV cargo and how they impact host cell function. To address this question, we analysed and compared the proteomes of BEVs released by the major human gastrointestinal tract (GIT) symbiont Bacteroides thetaiotaomicron (Bt) in vivo in fed versus fasted animals using nano-liquid chromatography with tandem mass spectrometry (LC-MSMS). Among the proteins whose abundance was negatively affected by fasting, nine of ten proteins of the serine protease family, including the regulatory protein dipeptidyl peptidase-4 (DPP-4), were significantly decreased in BEVs produced in the GITs of fasted animals. Strikingly, in extracellular vesicles produced by the intestinal epithelia of the same fasted mice, the proteins with the most increased abundance were serine protease inhibitors (serpins). Together, these findings suggest a dynamic interaction between GI bacteria and the host. Additionally, they indicate a regulatory role for the host in determining the balance between bacterial serine proteases and host serpins exported in bacterial and host extracellular vesicles. Full article

This review summarizes the interactions between Trypanosoma cruzi, the etiologic agent of Chagas disease, and its vectors, the triatomines, and highlights open questions. Four important facts should be emphasized at the outset: (1) The development of T. cruzi strains and their interactions with the mammalian host and the insect vector vary greatly. (2) Only about 10 of over 150 triatomine species have been studied for their interactions with the protozoan parasite. (3) The use of laboratory strains of triatomines makes generalizations difficult, as maintenance conditions influence the interactions. (4) The intestinal microbiota is involved in the interactions, but the mutualistic symbionts, Actinomycetales, have so far only been identified in four species of triatomines. The effects of the vector on T. cruzi are reflected in a different colonization ability of T. cruzi in different triatomine species. In addition, the conditions in the intestine lead to strong multiplication in the posterior midgut and rectum, with infectious metacyclic trypomastigotes developing almost exclusively in the latter. Starvation and feeding of the vector induce the development of certain stages of T. cruzi. The negative effects of T. cruzi on the triatomines depend on the T. cruzi strain and are particularly evident when the triatomines are stressed. The intestinal immunity of the triatomines responds to ingested blood-stage trypomastigotes of some T. cruzi strains and affects many intestinal bacteria, but not all and not the mutualistic symbionts. The specific interaction between T. cruzi and the bacteria is evident after the knockdown of antimicrobial peptides: the number of non-symbiotic bacteria increases and the number of T. cruzi decreases. In long-term infections, the suppression of intestinal immunity is indicated by the growth of specific microbiota. Full article

Maternally inherited endosymbionts are widespread in arthropods, with multiple symbionts commonly co-existing within a single host, potentially competing for or sharing limited host resources and space. Wolbachia and Rickettsia, two maternally-inherited symbionts in arthropods, can co-infect hosts, yet research on their combined impacts on host reproduction and interaction remains scarce. Tetranychus turkestani (Acari: Tetranychidae) is an important agricultural pest mite, characterized by rapid reproduction, a short life cycle, and being difficult to control. Wolbachia and Rickettsia are two major endosymbiotic bacteria present in T. turkestani. This study used diverse parthenogenetic backcross and antibiotic screening to explore the reproductive effects of these two symbionts on T. turkestani. The results show that single Rickettsia infection induced male killing in the amphigenesis of T. turkestani, leading to arrhenotokous embryo death and fewer offspring. Single Wolbachia infection induced strong cytoplasmic incompatibility (CI). During dual infection, CI intensity decreased because Rickettsia’s male-killing effect antagonized the Wolbachia-induced CI. Dual-infected mites had increased oviposition, lower mortality, a higher female-to-male ratio, and more offspring, thus enhancing T. turkestani’s fitness. These findings will be helpful for understanding the nature of host–endosymbiont interactions and the potential for evolutionary conflicts, offering insights into their co-evolutionary relationship. Full article

Numerous organisms, including animals, plants, fungi, protists, and bacteria, rely on toxins to meet their needs. Biological toxins have been classified into three groups: poisons transferred passively without a delivery mechanism; toxungens delivered to the body surface without an accompanying wound; and venoms conveyed to internal tissues via the creation of a wound. The distinctions highlight the evolutionary pathways by which toxins acquire specialized functions. Heretofore, the term venom has been largely restricted to animals. However, careful consideration reveals a surprising diversity of organisms that deploy toxic secretions via strategies remarkably analogous to those of venomous animals. Numerous plants inject toxins and pathogenic microorganisms into animals through stinging trichomes, thorns, spines, prickles, raphides, and silica needles. Some plants protect themselves via ants as venomous symbionts. Certain fungi deliver toxins via hyphae into infected hosts for nutritional and/or defensive purposes. Fungi can possess penetration structures, sometimes independent of the hyphae, that create a wound to facilitate toxin delivery. Some protists discharge harpoon-like extrusomes (toxicysts and nematocysts) that penetrate their prey and deliver toxins. Many bacteria possess secretion systems or contractile injection systems that can introduce toxins into targets via wounds. Viruses, though not “true” organisms according to many, include a group (the bacteriophages) which can inject nucleic acids and virion proteins into host cells that inflict damage rivaling that of conventional venoms. Collectively, these examples suggest that venom delivery systems—and even toxungen delivery systems, which we briefly address—are much more widespread than previously recognized. Thus, our understanding of venom as an evolutionary novelty has focused on only a small proportion of venomous organisms. With regard to this widespread form of toxin deployment, the words of the Sherman Brothers in Disney’s iconic tune, It’s a Small World, could hardly be more apt: “There’s so much that we share, that it’s time we’re aware, it’s a small world after all”. Full article

Insects often rely on symbiotic bacteria and fungi for various physiological processes, developmental stages, and defenses against parasites and diseases. Despite their significance, the associations between bacterial and fungal symbionts in Apis mellifera are not well studied, particularly in the Philippines. In this study, we collected A. mellifera from two different sites in the Municipality of Bacnotan, La Union, Philippines. A gut microbiome analysis was conducted using next-generation sequencing with the Illumina MiSeq platform. Bacterial and fungal community compositions were assessed using 16S rRNA and ITS gene sequences, respectively. Our findings confirm that adult worker bees of A. mellifera from the two locations possess distinct but comparably proportioned bacterial and fungal microbiomes. Key bacterial symbionts, including Lactobacillus, Bombilactobacillus, Bifidobacterium, Gilliamella, Snodgrassella, and Frischella, were identified. The fungal community was dominated by the yeasts Zygosaccharomyces and Priceomyces. Using the ENZYME nomenclature database and PICRUSt2 software version 2.5.2, a predicted functional enzyme analysis revealed the presence of β-glucosidase, catalase, glucose-6-phosphate dehydrogenase, glutathione transferase, and superoxide dismutase, which are involved in host defense, carbohydrate metabolism, and energy support. Additionally, we identified notable bacterial enzymes, including acetyl-CoA carboxylase and AMPs nucleosidase. Interestingly, the key bee symbionts were observed to have a negative correlation with other microbiota. These results provide a detailed characterization of the gut microbiota associated with A. mellifera in the Philippines and lay a foundation for further metagenomic studies of microbiomes in native or indigenous bee species in the region. Full article

The evolution of phytophagous insects has resulted in the development of feeding specializations that are unique to this group. The majority of current research on insect palatability has concentrated on aspects of ecology and biology, with relatively little attention paid to the role of insect gut symbiotic bacteria. Symbiont bacteria have a close relationship with their insect hosts and perform a range of functions. This research aimed to investigate the relationship between insect host plant range and gut symbiotic bacteria. A synthesis of the extant literature on the intestinal commensal bacteria of monophagous, oligophagous, and polyphagous tephritids revealed no evidence of a positive correlation between the plant host range and the diversity of larval intestinal microbial species. The gut symbionts of same species were observed to exhibit discrepancies between different literature sources, which were attributed to variations in multiple environmental factors. However, following beta diversity analysis, monophagy demonstrated the lowest level of variation in intestinal commensal bacteria, while polyphagous tephritids exhibited the greatest variation in intestinal commensal bacteria community variation. In light of these findings, this study proposes the hypothesis that exclusive or closely related plant hosts provide monophagy and oligophagy with a stable core colony over long evolutionary periods. The core flora is closely associated with host adaptations in monophagous and oligophagous tephritids, including nutritional and detoxification functions. This is in contrast to polyphagy, whose dominant colony varies in different environments. Our hypothesis requires further refinement of the data on the gut commensal bacteria of monophagy and oligophagy as the number of species and samples is currently limited. Full article