Microhabitat-specificity of the hindgut microbiota in higher termites

Termites are a group of eusocial insects in the superorder Dietyaptera, believed to have evolved from a lineage of ancient cockroach-like ancestors 150 million years ago. They play an important role in the breakdown of dead plant material, with the help of microorganisms harboured in the gut. The termites can be classified into flagellate-harbouring lower termites and flagellate-free higher termites. In comparison to the lower termites, the higher termites have undergone immense phylogenetic and dietary diversification, that has led to major changes in their gut structure. This diversification in the host is reflected in differences in their gut communities. To understand how host phylogeny and diet help shape bacterial communities in higher termites, I conducted an extensive pyrosequencingbased community survey of the gut communities of the major higher termite subfamilies, Macrotermitinae, Termitinae, and Nasutitermitinae. First, I constructed clone libraries and calculated phylogenetic trees for relevant bacterial taxa found in a variety of higher termites. The node information in these trees was used to provide a robust phylogenetic backbone for the accurate taxonomic assignment of the shorter pyrosequences. The analysis revealed that phylogenetically related termites in general, have similar community structure. However, one of the wood-feeding termites showed a greater similarity in gut community structure to other wood-feeders, in spite of not being phylogenetically related to them. The results suggest that although host phylogeny appears to be the major driving force in the determination of gut community membership, host diet can significantly contribute to community structure. However, far from being a homogenous environment, the higher termite gut is a highly structured habitat and shows the presence of spatially separated and physicochemically distinct compartments. Conditions unique to each compartment, playa significant role in shaping distinct compartment-specific communities. I used pyrotag sequencing to conduct an in-depth analysis of the communities of gut compartments from termites belonging to the families Termitinae and Nasutitermitinae. I found that homologous compartments from closely related termites are more similar in their community structure than adjacent compartments from the same termite. Based on our results, we hypothesize that similar ecological conditions such as increased alkalinity in the anterior gut, drive community structure in the gut compartments, and are reflected in overall hindgut community structure as well. The paunch (or P3 compartment) is the most voluminous of all hindgut compartments in wood-feeding higher termites, and is densely colonized by bacteria. Studies have shown that cellulase activity in the hindgut is particle-associated and possibly of bacterial origin. By fractionation of particles in the paunch lumen, using density-dependent centrifugation , I was able to show that the fraction enriched in wood fibers contributes substantially to the total cellulase activity in the hindgut. Using pyrosequencing, I examined the bacterial communities associated with the wood fibers in two wood-feeding members of the Nasutitermitinae. The results revealed the presence of a distinct cellulolytic fiber-associated community, primarily composed of the phyla TG3, Fibrobacteres and Spirochaetes. This fiber-associated community appears to have filled the niche for cellulose digestion, vacated by the flagellates. Lastly, the gut wall in termites is one of the major habitats in the gut, and home to an endospore-forming filamentous bacterium called 'Candidatus Arthromitus'. Due to the lack of a cultured isolate, the phylogenetic identity of 'Arthromitus' was disputed, and often confused with similar filamentous bacteria from mammalian guts. Phylogenetic analysis of picked filaments reveals 'Candidatus Arthromitus' to be a diverse clade of bacteria, found widely among arthropods, that is distinct from the segmented filamentous sequences recovered from mammalian guts

<i>Pycnoscelus surinamensis</i> cockroach gut microbiota respond consistently to a fungal diet without mirroring those of fungus-farming termites

The gut microbiotas of cockroaches and termites play important roles in the symbiotic digestion of dietary components, such as lignocellulose. Diet has been proposed as a primary determinant of community structure within the gut, acting as a selection force to shape the diversity observed within this "bioreactor", and as a key factor for the divergence of the termite gut microbiota from the omnivorous cockroach ancestor. The gut microbiota in most termites supports primarily the breakdown of lignocellulose, but the fungus-farming sub-family of higher termites has become similar in gut microbiota to the ancestral omnivorous cockroaches. To assess the importance of a fungus diet as a driver of community structure, we compare community compositions in the guts of experimentally manipulated Pycnoscelus surinamensis cockroaches fed on fungus cultivated by fungus-farming termites. MiSeq amplicon analysis of gut microbiotas from 49 gut samples showed a step-wise gradient pattern in community similarity that correlated with an increase in the proportion of fungal material provided to the cockroaches. Comparison of the taxonomic composition of manipulated communities to that of gut communities of a fungus-feeding termite species showed that although some bacteria OTUs shared by P. surinamensis and the farming termites increased in the guts of cockroaches on a fungal diet, cockroach communities remained distinct from those of termites. These results demonstrate that a fungal diet can play a role in structuring gut community composition, but at the same time exemplifies how original community compositions constrain the magnitude of such change

Условия формирования и перспективы обнаружения россыпных месторождений пылевидного золота в Украине

Изложены тезисы новой гипотезы гравитационной дифференциации мельчайших твердых частиц в жидкой и твердой, но дезинтегрированной средах. На этой основе прогнозируется образование россыпей пылевидного золота в дельтах Дона, Днепра, Днестра и Дуная, а также на прилегающих к ним частям шельфа Азово-Черноморского бассейна. Приведены доказательства биогенного и хемогенного генезиса некоторой части пылевидного золота. Приведен подсчет результата прогнозных ресурсов самородного мельчайшего золота по трем открытым автором россыпям на шельфе Черного моря, равный в сумме 25 т металла. Они были открыты только благодаря применению устройства “Говерла”.Викладено тези нової гіпотези гравітаційної диференціації дрібних твердих часток у твердому, але дезінтегрированому середовищі. На цій основі прогнозується утворення розсипів пилеподібного золота в дельтах Дону, Дніпра, Дністра й Дунаю, а також на прилеглих до них частинах шельфу Азово-Чорпоморського басейну. Наведено докази біогенного й хемогенного генезису деякої частини пилеподібного золота. Наведено результат підрахунку прогнозних ресурсів самородного найдрібні-шого золота по трьох відкритих автором розсипах на шельфі Чорного моря, які дорівнюють 25т металу. Розсипи були відкриті тільки завдяки використанню пристрою “Говерла”.It is expounded thesises for the new theory about gravitational differentiation of title rocky particles inside rocky environment. On this basis it is forecasted formation of gold flour placers in the deltas of Don, Dnieper, Dniester and Danube, and also on the adjoining part of the Azov-Black Sea shelf. There are introduced the evidence of biogenetical and chemogenetical genesis of some part of the gold flour. It is represented the prognosical resources of three gold placers which was discovered by author on the Black Sea shelf only due to using his device “Goverla”. They are amount to 25 ton of gold flour

Wood fibers are a crucial microhabitat for cellulose- and xylan- degrading bacteria in the hindgut of the wood-feeding beetle Odontotaenius disjunctus

IntroductionWood digestion in insects relies on the maintenance of a mosaic of numerous microhabitats, each colonized by distinct microbiomes. Understanding the division of digestive labor between these microhabitats- is central to understanding the physiology and evolution of symbiotic wood digestion. A microhabitat that has emerged to be of direct relevance to the process of lignocellulose digestion is the surface of ingested plant material. Wood particles in the guts of some termites are colonized by a specialized bacterial fiber-digesting microbiome, but whether this represents a widespread strategy among insect lineages that have independently evolved wood-feeding remains an open question.MethodsIn this study, we investigated the bacterial communities specifically associated with wood fibers in the gut of the passalid beetle Odontotaenius disjunctus. We developed a Percoll-based centrifugation method to isolate and enrich the wood particles from the anterior hindgut, allowing us to access the wood fibers and their associated microbiome. We then performed assays of enzyme activity and used short-read and long-read amplicon sequencing of the 16S rRNA gene to identify the composition of the fiber-associated microbiome.ResultsOur assays demonstrated that the anterior hindgut, which houses a majority of the bacterial load, is an important site for lignocellulose digestion. Wood particles enriched from the anterior hindgut contribute to a large proportion of the total enzyme activity. The sequencing revealed that O. disjunctus, like termites, harbors a distinct fiber-associated microbiome, but notably, its community is enriched in insect-specific groups of Lactococcus and Turicibacter.DiscussionOur study underscores the importance of microhabitats in fostering the complex symbiotic relationships between wood-feeding insects and their microbiomes. The discovery of distinct fiber-digesting symbionts in O. disjunctus, compared to termites, highlights the diverse evolutionary paths insects have taken to adapt to a challenging diet

Tartaric Acid Synthetic Derivatives for Multi-Drug Resistant Phytopathogen Pseudomonas and Xanthomonas Combating

The resistance to antimicrobial preparations, according the WHO reports of recent years, is becoming the one of the most actual healthcare problems of this century. Nevertheless, the key role of antibiotics diversity increase, as well as the increase of their application scopes, the initial origin of antimicrobial resistance problem is the versatility of adaptation mechanisms potential of all microorganisms, including intraspecific gene horizontal transfer and quorum sensing. Thus, the actuality of search of new, ecologically safe and harmless for human health antimicrobial agents, among the natural and semisynthetic compounds, is being significantly increased. One of the prospective directions in these research is the derivatization of aldaric acids, isolated from plants different species, as the native antibacterial active substances, such as like: citric, acetic, tartaric, lactic. &nbsp; In current research, 7 new derivatives of natural tartaric acid (TA): cyclohexylimide, benzylimide, phenylimide, benzyl mono amino salt, cyclohexyl mono amino salt, phenyl amino salt and mono ethanol amino salt of TA were tested on different strains from 6 subtypes of 3 species of phytopathogenic multi-drug resistant Xanthomonas and Pseudomonas. During the research it was detected the significant antimicrobial effect of studied compounds against the range of phytopathogens which are resistant to antibiotics from different classes and generations (ciprofloxacin, chloramphenicol, ceftriaxone, azithromycin, etc.). It was detected the higher efficiency of cyclohexyl- derivatives in comparison with mono ethanol-, phenyl- and benzyl- derivatives

Microhabitat-specificity of the hindgut microbiota in higher termites

Termites are a group of eusocial insects in the superorder Dietyaptera, believed to have evolved from a lineage of ancient cockroach-like ancestors 150 million years ago. They play an important role in the breakdown of dead plant material, with the help of microorganisms harboured in the gut. The termites can be classified into flagellate-harbouring lower termites and flagellate-free higher termites. In comparison to the lower termites, the higher termites have undergone immense phylogenetic and dietary diversification, that has led to major changes in their gut structure. This diversification in the host is reflected in differences in their gut communities. To understand how host phylogeny and diet help shape bacterial communities in higher termites, I conducted an extensive pyrosequencingbased community survey of the gut communities of the major higher termite subfamilies, Macrotermitinae, Termitinae, and Nasutitermitinae. First, I constructed clone libraries and calculated phylogenetic trees for relevant bacterial taxa found in a variety of higher termites. The node information in these trees was used to provide a robust phylogenetic backbone for the accurate taxonomic assignment of the shorter pyrosequences. The analysis revealed that phylogenetically related termites in general, have similar community structure. However, one of the wood-feeding termites showed a greater similarity in gut community structure to other wood-feeders, in spite of not being phylogenetically related to them. The results suggest that although host phylogeny appears to be the major driving force in the determination of gut community membership, host diet can significantly contribute to community structure. However, far from being a homogenous environment, the higher termite gut is a highly structured habitat and shows the presence of spatially separated and physicochemically distinct compartments. Conditions unique to each compartment, playa significant role in shaping distinct compartment-specific communities. I used pyrotag sequencing to conduct an in-depth analysis of the communities of gut compartments from termites belonging to the families Termitinae and Nasutitermitinae. I found that homologous compartments from closely related termites are more similar in their community structure than adjacent compartments from the same termite. Based on our results, we hypothesize that similar ecological conditions such as increased alkalinity in the anterior gut, drive community structure in the gut compartments, and are reflected in overall hindgut community structure as well. The paunch (or P3 compartment) is the most voluminous of all hindgut compartments in wood-feeding higher termites, and is densely colonized by bacteria. Studies have shown that cellulase activity in the hindgut is particle-associated and possibly of bacterial origin. By fractionation of particles in the paunch lumen, using density-dependent centrifugation , I was able to show that the fraction enriched in wood fibers contributes substantially to the total cellulase activity in the hindgut. Using pyrosequencing, I examined the bacterial communities associated with the wood fibers in two wood-feeding members of the Nasutitermitinae. The results revealed the presence of a distinct cellulolytic fiber-associated community, primarily composed of the phyla TG3, Fibrobacteres and Spirochaetes. This fiber-associated community appears to have filled the niche for cellulose digestion, vacated by the flagellates. Lastly, the gut wall in termites is one of the major habitats in the gut, and home to an endospore-forming filamentous bacterium called 'Candidatus Arthromitus'. Due to the lack of a cultured isolate, the phylogenetic identity of 'Arthromitus' was disputed, and often confused with similar filamentous bacteria from mammalian guts. Phylogenetic analysis of picked filaments reveals 'Candidatus Arthromitus' to be a diverse clade of bacteria, found widely among arthropods, that is distinct from the segmented filamentous sequences recovered from mammalian guts

Comparative Efficacy of a Fungal Entomopathogen with a Broad Host Range against Two Human-Associated Pests

The ability of a fungal entomopathogen to infect an insect depends on a variety of factors, including strain, host, and environmental conditions. Similarly, an insect&rsquo;s ability to prevent fungal infection is dependent on its biology, environment, and evolutionary history. Synanthropic pests have adapted to thrive in the indoor environment, yet they arose from divergent evolutionary lineages and occupy different feeding guilds. The hematophagous bed bug (Cimex lectularius) and omnivorous German cockroach (Blattella germanica) are highly successful indoors, but have evolved different physiological and behavioral adaptations to cope with the human-built environment, some of which also reduce the efficacy of fungal biopesticides. In order to gain greater insight into the host barriers that prevent or constrain fungal infection in bed bugs and German cockroaches, we tested different doses of Beauveria bassiana GHA through surface contact, topical application, feeding, and injection. Bed bugs were generally more susceptible to infection by B. bassiana with the mode of delivery having a significant impact on infectivity. The German cockroach was highly resilient to infection, requiring high doses of fungal conidia (&gt;8.8 &times; 104) delivered by injection into the hemocoel to cause mortality. Mortality occurred much faster in both insect species after exposure to surfaces dusted with dry conidia than surfaces treated with conidia suspended in water or oil. These findings highlight the importance of developing innovative delivery techniques to enhance fungal entomopathogens against bed bugs and cockroaches

Reevaluating Symbiotic Digestion in Cockroaches: Unveiling the Hindgut’s Contribution to Digestion in Wood-Feeding Panesthiinae (Blaberidae)

Cockroaches of the subfamily Panesthiinae (family Blaberidae) are among the few major groups of insects feeding on decayed wood. Despite having independently evolved the ability to thrive on this recalcitrant and nitrogen-limited resource, they are among the least studied of all wood-feeding insect groups. In the pursuit of unraveling their unique digestive strategies, we explored cellulase and xylanase activity in the crop, midgut, and hindgut lumens of Panesthia angustipennis and Salganea taiwanensis. Employing Percoll density gradient centrifugation, we further fractionated luminal fluid to elucidate how the activities in the gut lumen are further partitioned. Our findings challenge conventional wisdom, underscoring the significant contribution of the hindgut, which accounts for approximately one-fifth of cellulase and xylanase activity. Particle-associated enzymes, potentially of bacterial origin, dominate hindgut digestion, akin to symbiotic strategies observed in select termites and passalid beetles. Our study sheds new light on the digestive prowess of panesthiine cockroaches, providing invaluable insights into the evolution of wood-feeding insects and their remarkable adaptability to challenging, nutrient-poor substrates

The Genome of <i>Arsenophonus</i> sp. and Its Potential Contribution in the Corn Planthopper, <i>Peregrinus maidis</i>

The co-evolution between symbionts and their insect hosts has led to intricate functional interdependencies. Advances in DNA-sequencing technologies have not only reduced the cost of sequencing but, with the advent of highly accurate long-read methods, have also enabled facile genome assembly even using mixed genomic input, thereby allowing us to more easily assess the contribution of symbionts to their insect hosts. In this study, genomic data recently generated from Peregrinus maidis was used to assemble the genome of a bacterial symbiont, Pm Arsenophonus sp. This ~4.9-Mb assembly is one of the largest Arsenophonus genomes reported to date. The Benchmarking Universal Single-Copy Orthologs (BUSCO) result indicates that this Pm Arsenophonus assembly has a high degree of completeness, with 96% of the single-copy Enterobacterales orthologs found. The identity of the Pm Arsenophonus sp. was further confirmed by phylogenetic analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicates a major contribution by Pm Arsenophonus sp. to the biosynthesis of B vitamins and essential amino acids in P. maidis, where threonine and lysine production is carried out solely by Pm Arsenophonus sp. This study not only provides deeper insights into the evolutionary relationships between symbionts and their insect hosts, but also adds to our understanding of insect biology, potentially guiding the development of novel pest control methods