Bacterial endosymbiont Cardinium cSfur genome sequence provides insights for understanding the symbiotic relationship in Sogatella furcifera host

Background: Sogatella furcifera is a migratory pest that damages rice plants and causes severe economic losses. Due to its ability to annually migrate long distances, S.furcifera has emerged as a major pest of rice in several Asian countries. Symbiotic relationships of inherited bacteria with terrestrial arthropods have significant implications. The genus Cardinium is present in many types of arthropods, where it influences some host characteristics. We present a report of a newly # identified strain of the bacterial endosymbiont Cardinium cSfur in S. furcifera. Result: From the whole genome of S. furcifera previously sequenced by our laboratory, we assembled the whole genome sequence of Cardinium cSfur. The sequence comprised 1,103,593 bp with a GC content of 39.2%. The phylogenetic tree of the Bacteroides phylum to which Cardinium cSfur belongs suggests that Cardinium cSfur is closely related to the other strains (Cardinium cBtQ1 and cEper1) that are members of the Amoebophilaceae family. Genome comparison between the host-dependent endosymbiont including Cardinium cSfur and freeliving bacteria revealed that the endosymbiont has a smaller genome size and lower GC content, and has lost some genes related to metabolism because of its special environment, which is similar to the genome pattern observed in other insect symbionts. Cardinium cSfur has limited metabolic capability, which makes it less contributive to metabolic and biosynthetic processes in its host. From our findings, we inferred that, to compensate for its limited metabolic capability, Cardinium cSfur harbors a relatively high proportion of transport proteins, which might act as the hub between it and its host. With its acquisition of the whole operon related to biotin synthesis and glycolysis related genes through HGT event, Cardinium cSfur seems to be undergoing changes while establishing a symbiotic relationship with its host. Conclusion: A novel bacterial endosymbiont strain (Cardinium cSfur) has been discovered. A genomic analysis of the endosymbiont in S. furcifera suggests that its genome has undergone certain changes to facilitate its settlement in the host. The envisaged potential reproduction manipulative ability of the new endosymbiont strain in its S. furcifera host has vital implications in designing eco-friendly approaches to combat the insect pest

Research of working area development parameters in conditions of deep steep deposit finalizing

Отримано формули розрахунку об’єму запасів корисних копалин в приконтурній та глибинній зоні. Встановлено характер впливу параметрів доробки глибоких крутоспадних родовищ відкритим способом на доцільне положення поточних та проектних контурів кар’єру. Встановлено, що найменший середній коефіцієнт розкриву досягається при мінімальному значенні суми обсягів корисної копалини приконтурної зони лежачого і висячого боків покладу в проектному положенні. Найменший поточний коефіцієнт розкриву досягається при мінімальному значенні суми обсягів корисної копалини приконтурної зони лежачого і висячого боків покладу, а також робочого борту кар'єру в поточному положенні

An integrative approach to discovering cryptic species within the Bemisia tabaci whitefly species complex

Bemisia tabaci is a cryptic whitefly-species complex that includes some of the most damaging pests and plant-virus vectors of a diverse range of food and fibre crops worldwide. We combine experimental evidence of: (i) differences in reproductive compatibility, (ii) hybrid verification using a specific nuclear DNA marker and hybrid fertility confirmation and (iii) high-throughput sequencing-derived mitogenomes, to show that the “Mediterranean” (MED) B. tabaci comprises at least two distinct biological species; the globally invasive MED from the Mediterranean Basin and the “African silver-leafing” (ASL) from sub-Saharan Africa, which has no associated invasion records. We demonstrate that, contrary to its common name, the “ASL” does not induce squash silver-leafing symptoms and show that species delimitation based on the widely applied 3.5% partial mtCOI gene sequence divergence threshold produces discordant results, depending on the mtCOI region selected. Of the 292 published mtCOI sequences from MED/ASL groups, 158 (54%) are low quality and/or potential pseudogenes. We demonstrate fundamental deficiencies in delimiting cryptic B. tabaci species, based solely on partial sequences of a mitochondrial barcoding gene. We advocate an integrative approach to reveal the true species richness within cryptic species complexes, which is integral to the deployment of effective pest and disease management strategies

Heritable symbionts in a world of varying temperature

Heritable microbes represent an important component of the biology, ecology and evolution of many plants, animals and fungi, acting as both parasites and partners. In this review, we examine how heritable symbiont–host interactions may alter host thermal tolerance, and how the dynamics of these interactions may more generally be altered by thermal environment. Obligate symbionts, those required by their host, are considered to represent a thermally sensitive weak point for their host, associated with accumulation of deleterious mutations. As such, these symbionts may represent an important determinant of host thermal envelope and spatial distribution. We then examine the varied relationship between thermal environment and the frequency of facultative symbionts that provide ecologically contingent benefits or act as parasites. We note that some facultative symbionts directly alter host thermotolerance. We outline how thermal environment will alter the benefits/costs of infection more widely, and additionally modulate vertical transmission efficiency. Multiple patterns are observed, with symbionts being cold sensitive in some species and heat sensitive in others, with varying and non-coincident thresholds at which phenotype and transmission are ablated. Nevertheless, it is clear that studies aiming to predict ecological and evolutionary dynamics of symbiont–host interactions need to examine the interaction across a range of thermal environments. Finally, we discuss the importance of thermal sensitivity in predicting the success/failure of symbionts to spread into novel species following natural/engineered introduction

Pilot randomized controlled trial of restricted versus liberal crystalloid fluid management in pediatric post-operative and trauma patients

Background Intravenous (IV) fluid therapy is essential in the treatment of critically ill pediatric surgery and trauma patients. Recent studies have suggested that aggressive fluids may be detrimental to patients. Prospective studies are needed to compare liberal to restricted fluid management in these patients. The primary objective of this pilot trial is to test study feasibility—recruitment and adherence to the study treatment algorithm. Methods We conducted a two-part pilot randomized controlled trial (RCT) comparing liberal to restricted crystalloid fluid management in 50 pediatric post-operative (1–18 years) and trauma (1–15 years) patients admitted to our pediatric intensive care unit (PICU). Patients were randomized to a high (liberal) volume or low (restricted) volume algorithm using unblinded, blocked randomization. A revised treatment algorithm was used after the 29th patient for the second part of the RCT. The goal of the trial was to determine the feasibility of conducting an RCT at a single site for recruitment and retention. We also collected data on the safety of study interventions and clinical outcomes, including pulmonary, infectious, renal, post-operative, and length of stay outcomes. Results Fifty patients were randomized to either liberal (n = 26) or restricted (n = 24) fluid management strategy. After data was obtained on 29 patients, a first study analysis was performed. The volume of fluid administered and triggers for intervention were adapted to optimize the treatment effect and clarity of outcomes. Updated and refined fluid management algorithms were created. These were used for the second part of the RCT on patients 30–50. During this second study period, 54% (21/39, 95% CI 37–70%) of patients approached were enrolled in the study. Of the patients enrolled, 71% (15/21, 95% CI 48–89%) completed the study. This met our a priori recruitment and retention criteria for success. A data safety monitoring committee concluded that no adverse events were related to study interventions. Although the study was not powered to detect differences in outcomes, after the algorithm was revised, we observed a non-significant trend towards improved pulmonary outcomes in patients on the restricted arm, including decreased need for and time on oxygen support and decreased need for mechanical ventilation. Conclusion We demonstrated the feasibility and safety of conducting a single-site RCT comparing liberal to restricted crystalloid fluid management in critically ill pediatric post-operative and trauma patients. We observed trends in improved pulmonary outcomes in patients undergoing restricted fluid management. A definitive multicenter RCT comparing fluid management strategies in these patients is warranted. Trial registration ClinicalTrials.gov, NCT04201704. Registered 17 December 2019—retrospectively registered

Still a Host of Hosts for Wolbachia: Analysis of Recent Data Suggests That 40% of Terrestrial Arthropod Species Are Infected

Wolbachia are intracellular bacteria that manipulate the reproduction of their arthropod hosts in remarkable ways. They are predominantly transmitted vertically from mother to offspring but also occasionally horizontally between species. In doing so, they infect a huge range of arthropod species worldwide. Recently, a statistical analysis estimated the infection frequency of Wolbachia among arthropod hosts to be 66%. At the same time, the authors of this analysis highlighted some weaknesses of the underlying data and concluded that in order to improve the estimate, a larger number of individuals per species should be assayed and species be chosen more randomly. Here we apply the statistical approach to a more appropriate data set from a recent survey that tested both a broad range of species and a sufficient number of individuals per species. Indeed, we find a substantially different infection frequency: We now estimate the proportion of Wolbachia-infected species to be around 40% which is lower than the previous estimate but still points to a surprisingly high number of arthropods harboring the bacteria. Notwithstanding this difference, we confirm the previous result that, within a given species, typically most or only a few individuals are infected. Moreover, we extend our analysis to include several reproductive parasites other than Wolbachia that were also screened for in the aforementioned empirical survey. For these symbionts we find a large variation in estimated infection frequencies and corroborate the finding that Wolbachia are the most abundant endosymbionts among arthropod species

The diversity of reproductive parasites among arthropods: Wolbachia do not walk alone

<p>Abstract</p> <p>Background</p> <p>Inherited bacteria have come to be recognised as important components of arthropod biology. In addition to mutualistic symbioses, a range of other inherited bacteria are known to act either as reproductive parasites or as secondary symbionts. Whilst the incidence of the α-proteobacterium <it>Wolbachia </it>is relatively well established, the current knowledge of other inherited bacteria is much weaker. Here, we tested 136 arthropod species for a range of inherited bacteria known to demonstrate reproductive parasitism, sampling each species more intensively than in past surveys.</p> <p>Results</p> <p>The inclusion of inherited bacteria other than <it>Wolbachia </it>increased the number of infections recorded in our sample from 33 to 57, and the proportion of species infected from 22.8% to 32.4%. Thus, whilst <it>Wolbachia </it>remained the dominant inherited bacterium, it alone was responsible for around half of all inherited infections of the bacteria sampled, with members of the <it>Cardinium</it>, <it>Arsenophonus </it>and <it>Spiroplasma ixodetis </it>clades each occurring in 4% to 7% of all species. The observation that infection was sometimes rare within host populations, and that there was variation in presence of symbionts between populations indicates that our survey will itself underscore incidence.</p> <p>Conclusion</p> <p>This extensive survey demonstrates that at least a third of arthropod species are infected by a diverse assemblage of maternally inherited bacteria that are likely to strongly influence their hosts' biology, and indicates an urgent need to establish the nature of the interaction between non-<it>Wolbachia </it>bacteria and their hosts.</p

Going Solo: Discovery of the First Parthenogenetic Gordiid (Nematomorpha: Gordiida)

Despite the severe fitness costs associated with sexual reproduction, its persistence and pervasiveness among multicellular organisms testifies to its intrinsic, short-term advantages. However, the reproductive assurance hypothesis predicts selection favoring asexual reproduction in sparse populations and when mate finding is difficult. Difficulties in finding mates is especially common in parasites, whose life cycles involve multiple hosts, or being released from the host into the external environment where the parasite can find itself trapped without a sexual partner. To solve this problem and guarantee reproduction, parasites in numerous phyla have evolved reproductive strategies, as predicted by the reproductive assurance hypothesis, such as hermaphroditism or parthenogenesis. However, this type of strategy has not been reported from species in the phylum Nematomorpha, whose populations have often been described as sparse. A new Nematomorpha species, Paragordius obamai n. sp., was discovered from Kenya, Africa, and appears to have solved the problem of being trapped without a mate by eliminating the need for males. Paragordius obamai n. sp. represents the first and only known species within this phylum to reproduce asexually. To determine the mechanism of this mating strategy, we ruled out the involvement of reproduction manipulating endosymbionts by use of next generation sequencing data, thus suggesting that parthenogenesis is determined genetically and may have evolved as a means to assure reproduction. Since this new parthenogenetic species and a closely related gonochoristic North American congener, P. varius, are easy to propagate in the laboratory, these gordiids can be used as model systems to test hypotheses on the genetic advantages and disadvantages of asexual reproduction and the genetic determinants of reproductive strategies in parasites

A novel Borrelia species, intermediate between Lyme disease and relapsing fever groups, in neotropical passerine-associated ticks

Lyme disease (LD) and relapsing fevers (RF) are vector-borne diseases caused by bacteria of the Borrelia genus. Here, we report on the widespread infection by a non-described Borrelia species in passerine-associated ticks in tropical rainforests of French Guiana, South America. This novel Borrelia species is common in two tick species, Amblyomma longirostre and A. geayi, which feed on a broad variety of neotropical mammal and bird species, including migratory species moving to North America. The novel Borrelia species is divergent from the LD and RF species, and is more closely related to the reptile- and echidna-associated Borrelia group that was recently described. Genome sequencing showed that this novel Borrelia sp. has a relatively small genome consisting of a 0.9-Mb-large chromosome and an additional 0.3 Mb dispersed on plasmids. It harbors an RF-like genomic organization but with a unique mixture of LD- and RF-specific genes, including genes used by RF Borrelia for the multiphasic antigen-switching system and a number of immune-reactive protein genes used for the diagnosis of LD. Overall, our data indicate that this novel Borrelia is an intermediate taxon between the LD and RF species that may impact a large host spectrum, including American mammals. The designation “Candidatus Borrelia mahuryensis” is proposed for this species