Region Sequences Research Articles

Molecular identification of wood-decaying fungi of <i>Armillaria</i> genus widespread in Eastern Siberia and the Far East of Russia using ITS, IGS-1-1 and <i>Tef-1α</i> genetic markers

The genus Armillaria is an essential component of forest ecosystems playing very important ecological role in dead wood decomposition, but it often becomes a serious pathogen causing white root rot in trees. It is also known that Armillaria species significantly differ in the level of pathogenicity. Thus, accurate identification of Armillaria is critical for assessing the risk of tree disease. In this study we analyzed 28 Armillaria isolates from Siberia and the Far East using nucleotide sequences of ITS, IGS-1-1 and TEF-1α gene regions and generated phylogenetic trees based on maximum likelihood method. In total, four Armillaria species were identified: A borealis, A. cepistipes, A. ostoyae and A. gallica. A. borealis was the most frequent among collected isolates (18 out of 28 isolates). A. gallica, A. cepistipes and A. ostoyae were much less frequent with two, five and three isolates out of 28, respectively. Thedistribution of Armillaria species in Siberia and the Far East was described for the first time. It is concluded that further studies are necessary to determine the role of Armillaria in trees pathological dieback, and A. borealis should be a key focus.

Deep Sequencing and Phenotyping in an Australian Tuberous Sclerosis Complex "No Mutations Identified" Cohort.

We describe the phenotypes in an Australian TSC NMI group (n = 18) and a molecular testing strategy implementable in a diagnostic laboratory. Massively parallel sequencing (MPS) of the whole genomic regions of TSC1 and TSC2 was performed using DNA extracted from multiple tissue samples per participant. Our study showed that the phenotype in TSC NMI individuals can be similar to those with heterozygous, particularly TSC1, variants. Although neurodevelopmental outcomes can be less severe, the number of organ systems involved was similar to the non-mosaic groups. A diagnostic yield of 72% (13/18) was achieved, with the majority (10/13) being mosaic variants and the remainder heterozygous variants missed on previous testing. Testing DNA from multiple tissue samples allowed for validation of otherwise discarded low-level mosaic variants and detection of mosaic variants by MPS without excessive cost or the need for specialised techniques. Implementing this approach in a diagnostic setting is viable and allows optimal clinical care of patients with NMI TSC.

Contrasting Patterns of Genetic Diversity in European Mammals in the Context of Glacial Refugia

Phylogeographic studies have been conducted on many different mammal species in order to track their recent demographic histories. The climatic fluctuations associated with the Last Glacial Maximum (LGM) appear to have had a profound influence on the geographic patterning of genetic diversity in mammals. However, most phylogenetic studies have focused on single species. Few have used a holistic approach covering multiple taxa to explore common patterns. Here, we conducted meta-analyses of mitochondrial DNA control region sequences, identifying haplotype diversity and private allelic richness patterns in a geographic context. Four general patterns emerged among European mammals: an east–west decline in variation, a Western-Central belt of the highest diversity, southern richness, and homogeneity with no geographic pattern. These patterns likely reflect the refugial origins of modern populations. The east–west variation decline suggests species with eastern LGM refugia; the Western-Central belt of the highest diversity may harbor taxa with cryptic northern refugia, while southern richness may correspond to traditional southern refugia. Species with homogeneity and no geographic pattern may have been panmictic without a specific refugium or may reflect the occurrence of both southern and cryptic northern refugia. Surprisingly, the “no pattern” phenomenon is seldom discussed and may frequently have been discounted. Our study emphasizes the importance of considering multiple taxa, providing valuable insights into the responses of European mammals to past climatic changes.

Hydrocarbon-Oxidizing Bacteria of the Bottom Ecotopes of the Barents and Pechora Seas

Microorganisms capable of degrading hydrocarbons are regular components of natural microbial communities and play an important role in self-purification of marine environments from oil contamination. High-throughput sequencing of the 16S rRNA gene V4 variable region was used to analyze microbial communities of the Barents and Pechora seas and of the microcosms with a spectrum of hydrocarbon substrates: oil, n-nonane, n-undecane, and phenanthrene. The Barents Sea communities of hydrocarbon-oxidizing microorganisms were characterized by predominance of the genera Pseudoalteromonas, Pseudomonas, Porticoccus, and Oleispira, while those of the Pechora Sea contained members of the genera Rhodococcus, Dietzia, Sphingorhabdus, and Hyphomonas. Pure cultures of these microorganisms were shown to utilize the major oil hydrocarbons: n-alkanes, cycloalkanes, and aromatic compounds.

Discovery of <i>Brevibacterium</i> predominating in fecal samples from three children with persistent diarrhea negative for common pathogens

Acute diarrhea is a common disease in children under 5 years old and can develop into persistent diarrhea, greatly affecting the children's health. Although advanced techniques had been used to diagnose and detect common pathogens in hospitals, however, 40% of cases are negative for the pathogens. In this study, to investigate dominant bacteria in stool samples of three persistent-diarrheal children with unidentified pathogenic agents, the V3 and V68 regions of the 16S rRNA gene were amplified from fecal bacterial metagenomic DNA, separated on DGGE gel, and the dominant DNA bands were sequenced. As a result, the V3 and V68 regions of bacteria in persistent diarrheal children were less diverse and different from the corresponding DNA bands of the indicator strains. Sequence analysis and similarity comparison of six DNA bands of V3 regions and seven DNA bands of V68 regions showed that two V3 sequences (of 160 bp) derived from two samples were novel and did not match any genes from the non-redundant database, but they shared 93.75% similarity to each other. The four V3 sequences left derived from all three samples were the most similar (94.53-100%) with the corresponding genes of Brevibacterium. Six of the seven V68 sequences derived from dominant DNA bands of all three samples were the most similar (from 99.4% to 100%) to the corresponding genes of referent strains belonging to the genus Enterococcus. In sample D3, a sequence of the V68 region possessed 100% identity to the E. faecalis ATCC 19433 strain. This is the first study report that Brevibacterium was the dominant bacteria in the gastrointestinal microflora of children with persistent diarrhea although the bacterial genus has been reported to cause dangerous diseases in humans with immunodeficiency.

Full-length single-cell BCR sequencing paired with RNA sequencing reveals convergent responses to pneumococcal vaccination

Single-cell RNA sequencing (scRNA-seq) can resolve transcriptional features from individual cells, but scRNA-seq techniques capable of resolving the variable regions of B cell receptors (BCRs) remain limited, especially from widely-used 3′-barcoded libraries. Here, we report a method that can recover paired, full-length variable region sequences of BCRs from 3′-barcoded scRNA-seq libraries. We first verify this method (B3E-seq) can produce accurate, full-length BCR sequences. We then apply this method to profile B cell responses elicited against the capsular polysaccharide of Streptococcus pneumoniae serotype 3 (ST3) by glycoconjugate vaccines in five infant rhesus macaques. We identify BCR features associated with specificity for the ST3 antigen which are present in multiple vaccinated monkeys, indicating a convergent response to vaccination. These results demonstrate the utility of our method to resolve key features of the B cell repertoire and profile antigen-specific responses elicited by vaccination.

Wide circulation of type 1 vaccine-derived poliovirus strains in clinical specimens from suspected cases of poliomyelitis, their contacts and in wastewater in Madagascar since late 2020

Madagascar has faced three major outbreaks of vaccine-derived polioviruses (VDPVs) in recent decades, with VDPV type 1 reemerging in late 2020. Here, we report the molecular characterization of these cVDPV1 strains. WHO protocols were used for poliovirus detection in stool and wastewater samples. Molecular genotyping was based on the 5′ non-coding (5′NC), VP1, and 3Dpol regions. From 2020 to 2022, 92 of 5690 stool samples and 129 of 1046 wastewater samples tested positive for cVDPV1. Genetic analysis of the VP1 gene revealed 1.3%–6.1% variability compared to the Sabin strain. Most sequences showed mutations at neurovirulence attenuation sites. Phylogenetic analysis distributed strains into four genogroups originating from Southern Madagascar. All analyzed cVDPV1 strains were recombinant, containing mutated oral polio vaccine sequences in VP1 and type C enterovirus sequences in other regions. This study demonstrated that all strains were closely related during this epidemic.

Transmission network of Hepatitis C virus subtype 2a in Huazhou County, Shaanxi Province, China

BackgroundHuazhou County has one of the highest rates of hepatitis C virus (HCV) infection incidence and prevalence in Shaanxi Province, northwest China. Understanding the characteristics of HCV transmission patterns in this area could help guide targeted prevention strategies. This study employed phylogenetic analysis and the construction of a molecular transmission network of HCV-infected people in Huazhou County to describe the predominant strains of HCV and identify factors associated with onward transmission.MethodsWhole blood samples were obtained from HCV RNA-positive individuals for sequencing of the non-structural protein 5B region. A maximum-likelihood (ML) phylogenetic tree was constructed to determine HCV subgenotypes, and Bayesian phylogenetic analysis was employed to estimate the evolutionary history. The transmission network was constructed using the ML phylogenetic tree and pairwise distances. Logistic regression was used to identify factors associated with clustering in the transmission network.ResultsML phylogenetic analysis confirmed that the 61 sequences analyzed in the study belonged to subtype 2a. Bayesian phylogenetic analysis showed that the majority of subtype 2a sequences originated in the northwest of China and had descended approximately 8 to 20 years before sampling. Overall, 26.2% of participant sequences were grouped into phylogenetic network clusters. Multivariate logistic regression showed that individuals who had a history of blood transfusions and were living in Shi Village, Huazhou County, were more likely to form clusters within the transmission network.ConclusionHCV transmission in Huazhou County was predominantly associated with subtype 2a. Having a history of blood transfusions and living in residential Shi Village, Huazhou County, were factors associated with a high risk of HCV infection transmission. Prioritizing targeted interventions for these patient groups may help to prevent further infections.

Retrospective analysis of diet and gut microbiota diversity and clinical pharmacology outcomes in patients with Parkinsonism syndrome

BackgroundParkinson's disease (PD) is a global neurodegenerative ailment impacting millions, causes significant degeneration of dopaminergic neurons in the substantia nigra. Emerging research underscores the gut microbiota's role in PD onset. Yet, investigations in Chinese demographics are lacking. This study thus targets a retrospective examination of gut microbiota variety and clinical aspects in Chinese PD patients. MethodsWe retrospectively analyzed 50 PD patients' clinical data (admitted May 2021–April 2022) and compared their gut microbiota composition and abundance via 16S rDNA V3-V4 region sequencing against 50 healthy controls. The study also explored links between disease severity and PD patients' gut microbiota. ResultsWe found that the gut microbiota diversity was increased in PD patients. Specifically, phyla Firmicutes, Actinobacteria, and Proteobacteria were more abundant, whereas Bacteroidetes was less abundant compared to controls. Gut microbiota diversity did not vary between early-vs. late-onset PD, tremor-dominant vs. non-tremor-dominant, or constipation-associated vs. non-constipation-associated subtypes. The abundance of Firmicutes was positively correlated with UPDRS (Unified Parkinson's Disease Rating Scale) III score, NMSS (Non-Motor Symptoms Scale) score, Wexner score, and PDQ-39 (Parkinson's Disease Questionnaire-39) score; the abundance of Actinobacteria was positively correlated with UPDRS III, NMSS, Wexner, and PDQ-39 scores; and the abundance of Bacteroidetes was negatively correlated with UPDRS III, NMSS, Wexner, and PDQ-39 scores. At the family level, the abundance of Bifidobacteriaceae, Enterobacteriaceae, and Porphyromonadaceae was positively correlated with UPDRS III, NMSS, and PDQ-39 scores. ConclusionCompared with healthy individuals, PD patients have increased gut microbiota diversity, and the abundance of Bifidobacteriaceae, Enterobacteriaceae, and Porphyromonadaceae is associated with the severity of both motor and non-motor symptoms in PD patients.

Genomic identification of Oryctes rhinoceros nudivirus isolates, a biocontrol agent for coconut rhinoceros beetle

The coconut rhinoceros beetle (Oryctes rhinoceros, CRB) is a serious pest of coconut and oil palms. It is native to South and Southeast Asia and was inadvertently introduced to Samoa in 1909. It has invaded many other Pacific countries throughout the last century. Oryctes rhinoceros nudivirus (OrNV), a natural pathogen of CRB in its native range, was successfully introduced as a classical biocontrol agent and has effectively suppressed invasive CRB populations for decades. However, resurgence of CRB has been recorded, with new invasions detected in several Pacific Island Countries and Territories. Additionally, new populations of CRB are emerging in some invaded areas that have a degree of resistance to the virus isolates commonly released for CRB biocontrol. Here, we designed a fast and reliable tool for distinguishing between different OrNV isolates that can help with the selection process to identify effective isolates for management of new CRB invasions. A comparison of 13 gene/gene region sequences within the OrNV genome of 16 OrNV isolates from native and invaded ranges allowed us to identify unique Single Nucleotide Polymorphisms (SNPs). With these SNPs, we developed an assay using multiplex PCR-amplicon-based nanopore sequencing to distinguish between OrNV isolates. We found that as few as four gene fragments were sufficient to identify 15 out of 20 OrNV isolates. This method can be used as a tool to monitor the establishment and distribution of OrNV isolates selected for release as biocontrol agents in CRB-infected areas.

Molecular Study of Varicella zoster virus in Cerebrospinal Fluid from Stroke Patients of Thi-Qar province.

Varicella zoster virus (VZV) is a type of alpha-herpesvirus that specifically targets the nervous system. The initial infection, typically occurring during childhood, results in varicella (commonly known as chickenpox), after which the virus enters a dormant state in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia throughout the entire neuroaxis. Molecular and genetic studies of viruses are an important tool for virus development and identifying viral treatments to combat the diseases. The aim of the study was to determine the whole ORF4 sequence of the local VZV strains for phylogenetic analysis to determine the variability in the viral sequence. Ten samples of VZV DNA were subjected to the sequencing of the whole ORF4 region following identification using the PCR method. Sequences from five samples have been successfully analyzed. All clinical strains were discovered to possess a genome with a length of 124,884 base pairs. The sequences exhibited the occurrence of two distinct mutations, one being a transversion and the other a transition, with the latter resulting in an alteration of the amino acid. A phylogenetic tree was constructed using the maximum likelihood method based on the sequences of five nucleotide sequences from clinical samples and nine reference VZV strains. The tree displayed the evolutionary distances between these sequences. The analysis of the phylogenetic tree revealed the presence of five primary clades, with four of them originating from India (isolates S1, S2, S4, S5), while S3 exhibited similarity to a strain from the United Kingdom.

Exploring the impact of plant genotype and fungicide treatment on endophytic communities in tomato stems.

This study examines how plant genotype can influence the microbiome by comparing six tomato genotypes (Solanum lycopersicum) based on their traditional vs. commercial backgrounds. Using Illumina-based sequencing of the V6-V8 regions of 16S and ITS2 rRNA genes, we analyzed and compared the endophytic bacterial and fungal communities in stems to understand how microbiota can differ and be altered in plant genotypes and the relation to human manipulation. Our results reflect that traditional genotypes harbor significantly more exclusive microbial taxa and a broader phylogenetic background than the commercial ones. Traditional genotypes were significantly richer in Eurotiomycetes and Sordariomycetes fungi, while Lasiosphaeriaceae was more prevalent in commercial genotypes. TH-30 exhibited the highest bacterial abundance, significantly more than commercial genotypes, particularly in Actinomycetia, Bacteroidia, and Gammaproteobacteria. Additionally, traditional genotypes had higher bacterial diversity, notably in orders like Cytophagales, Xanthomonadales, and Burkholderiales. Moreover, we performed an evaluation of the impact of a systemic fungicide (tebuconazole-dichlofluanide) to simulate a common agronomic practice and determined that a single fungicide treatment altered the stem endophytic microbiota. Control plants had a higher prevalence of fungal orders Pleosporales, Helotiales, and Glomerellales, while treated plants were dominated by Sordariomycetes and Laboulbeniomycetes. Fungal community diversity significantly decreased, but no significant impact was observed on bacterial diversity. Our study provides evidence that the background of the tomato variety impacts the fungal and bacterial stem endophytes. Furthermore, these findings suggest the potential benefits of using of traditional genotypes as a source of novel beneficial microbiota that may prove highly valuable in unpredicted challenges and the advancement in sustainable agriculture.

Isolation of phage-antibodies against Eimeria species that infect chickens

Eimeria is one of the most economically important pathogens in poultry production. Diagnosis of infection has the potential to inform treatment and prevention strategies. Here, phage display technology was used to isolate single chain antibodies (scFvs) that had a broad specificity against oocysts from the seven pathogenic species of Eimeria found in poultry. Three such scFvs, representing 2 scFv HCDR3 motifs, were isolated by random picks of clones isolated after five rounds of iterative enrichment (panning) of phage against the seven Eimeria species. Phage-antibody binding to Eimeria oocysts was also interrogated using next generation sequencing of the HCDR3 region of scFv genes contained with phage particles. This analysis demonstrated that the most abundant scFv found after 5 rounds of panning accounted for over >90 % of scFvs. Furthermore, the three scFvs isolated from random picks of clones were the only antibodies that were enriched through each round of panning. They were also seen to be enriched through the stages of phage panning that included binding to the Eimeria oocysts (selection phase) and to be selected against during the stages that consisted solely of phage propagation (growth only phase). The NGS data was further analysed to identify an additional scFv that demonstrated specific enrichment against 3 Eimeria species at the third round of panning and had the same pattern of enrichment during the selection and growth phases of panning. Rescue and analysis of this phage-scFv demonstrated a binder with broad specificity for Eimeria species. The four antibodies with broad specificity detected all seven Eimeria species in immunoassays. The binding of one such scFv that recognised all species was further validated by fluorescent microscopy.

The Effects of Brodalumab on the Fungal Microbiome in Patients with Psoriasis.

The gut microbiota plays a critical role in immune system function, with dysbiosis linked to systemic inflammation, contributing to conditions like psoriasis and depression. Although biological treatments for severe psoriasis are known to impact gut bacteria, less is understood about their effects on fungi. This study aims to investigate fungal gut microbiota changes in psoriasis patients transitioning from TNF-α inhibitors to brodalumab. Fecal samples from 20 patients were analyzed using Illumina MiSeq sequencing of the ITS2 region of 18S rRNA. Microbial diversity was assessed through Bray-Curtis dissimilarity and the Shannon-Wiener index. Clinical outcomes were measured using clinical scores for psoriasis and depression severity, with statistical analysis performed via Wilcoxon signed-rank tests and PERMANOVA. Results showed that Ascomycota was the dominant fungal phylum in both treatment groups, with Saccharomyces, Penicillium, Candida, and Debaryomyces as prevalent genera. No significant changes occurred at the phylum level after switching to brodalumab, though minor genome-level variations were observed. Beta diversity analysis highlighted inter-patient variability, with no significant correlation between fungal composition and clinical outcomes. Despite improved clinical scores, the fungal gut microbiota remained largely stable, suggesting that brodalumab does not significantly alter fungal communities in psoriasis patients. Further research is needed for a comprehensive understanding.

Flagellar switch inverted repeat impacts flagellar invertibility and varies Clostridioides difficile RT027/MLST1 virulence.

Clostridioides difficile RT027 strains cause infections that vary in severity from asymptomatic to lethal, but the molecular basis for this variability is poorly understood. Through comparative analyses of RT027 clinical isolates, we determined that isolates that exhibit greater variability in their flagellar gene expression exhibit greater virulence in vivo. C. difficile flagellar genes are phase-variably expressed due to the site-specific inversion of the flgB 5'UTR region, which reversibly generates ON vs. OFF orientations for the flagellar switch. We found that longer inverted repeat (IR) sequences in this switch region correlate with greater disease severity, with RT027 strains carrying 6A/6T IR sequences exhibiting greater phenotypic heterogeneity in flagellar gene expression (60%-75% ON) and causing more severe disease than those with shorter IRs (> 99% ON or OFF). Taken together, our results reveal that phenotypic heterogeneity in flagellar gene expression may contribute to the variable disease severity observed in C. difficile patients.

Phosphorylation of VapB antitoxins affects intermolecular interactions to regulate VapC toxin activity in Mycobacterium tuberculosis.

Toxin-antitoxin modules are present in many bacterial pathogens. The VapBC family is particularly abundant in members of the Mycobacterium tuberculosis complex, with 50 modules present in the M. tuberculosis genome. In type IIA modules, the VapB antitoxin protein binds to and inhibits the activity of the co-expressed cognate VapC toxin protein. VapB proteins may also bind to promoter region sequences and repress the expression of the vapB-vapC operon. Though VapB-VapC interactions can control the amount of free VapC toxin in the bacterial cell, the mechanisms that affect this interaction are poorly understood. Based on our recent finding of Ser/Thr phosphorylation of VapB proteins in M. tuberculosis, we substituted phosphomimetic or phosphoablative amino acids at the phosphorylation sites of two VapB proteins. We found that phosphomimetic substitution of VapB27 and VapB46 resulted in decreased interaction with their respective cognate VapC proteins, whereas phosphoablative substitution did not alter binding. Similarly, we determined that phosphomimetic substitution interfered with VapB binding to promoter region DNA sequences. Both decreased VapB-VapC interaction and decreased VapB repression of vapB-vapC operon transcription would result in increased free VapC in the M. tuberculosis cell. In growth inhibition experiments, M. tuberculosis strains expressing vapB46-vapC46 constructs containing a phosphoablative vapB mutation resulted in lower toxicity compared to a strain expressing native vapB46, whereas similar or greater toxicity was observed in the strain expressing the phosphomimetic vapB mutation. These results identify a novel mechanism by which VapC toxicity activity can be regulated by VapB phosphorylation.IMPORTANCEIntracellular bacterial toxins are present in many bacterial pathogens and have been linked to bacterial survival in response to stresses encountered during infection. The activity of many toxins is regulated by a co-expressed antitoxin protein that binds to and sequesters the toxin protein. The mechanisms by which an antitoxin may respond to stresses to alter toxin activity are poorly understood. Here, we show that antitoxin interactions with its cognate toxin and with promoter DNA required for antitoxin and toxin expression can be altered by Ser/Thr phosphorylation of the antitoxin and, thus, affect toxin activity. This reversible modification may play an important role in regulating toxin activity within the bacterial cell in response to signals generated during infection.

Influence of Immersion Orientation on Microstructural Evolution and Deformation Behavior of 40Cr Steel Automobile Front Axle during Oil Quenching.

This study employs the finite element method to investigate the microstructural evolution and deformation behavior of a 40Cr steel automobile front axle during the quenching process. By establishing a multi-physics field coupling model, the study elucidates the variation patterns of the microstructure field in the quenching process of the front axle under different immersion orientations. It is found that along the length direction, the bainite and martensite structures decrease from the center to the edge region, while the ferrite structure shows an increasing trend. Additionally, the influence of immersion orientation on the hardness of the front axle's microstructure and deformation behavior is thoroughly discussed. The results indicate that, firstly, when quenched horizontally, the hardness difference among different regions of the front axle is approximately 8.2 HRC, whereas it reaches 10.3 HRC when quenched vertically. Considering the uniformity of the microstructure, the horizontal immersion method is preferable. Secondly, due to the different immersion sequences in different regions of the front axle leading to varying heat transfer rates, as well as the different amounts of martensite structures obtained in different regions, the deformation decreases along the length direction from the center to the edge region. Horizontal immersion quenching, compared to vertical immersion, results in a reduction of approximately 56.2% and 48.9% in deformation on the representative central cross-section (A-A) and the total length of the front axle, respectively. Therefore, considering aspects such as microstructure uniformity and deformation, the horizontal immersion quenching orientation is more favorable.

Two species of the green algae Volvox sect. Volvox from the Japanese ancient lake, Lake Biwa.

Volvox sect. Volvox is a group of green algae with unique morphological features (thick cytoplasmic bridges between somatic cells and spiny zygote walls) and a worldwide distribution. Despite research interest in the diversity of organisms in ancient lakes, Volvox sect. Volvox from ancient lakes worldwide has not been identified to the species level. Here, we established clonal cultures of two species of this group originating from Lake Biwa, an ancient lake in Japan, and performed identification based on morphological and molecular data. One was identified as Volvox kirkiorum based on the nuclear ribosomal DNA internal spacer region (ITS) sequence, bisexual (monoicous or monoecious) spheroids, and zygote morphology. The other showed genetic separation from related species based on the secondary structure of the ITS and results of phylogenetic analysis of a combined data set from the nuclear actin gene, ITS, and two plastid genes (large subunit of RuBisCO and photosystem II CP43 apoprotein gene); it represented a new phylogenetic lineage within Volvox sect. Volvox, suggesting possible endemism in Lake Biwa. This species produced bisexual spheroids with different zygote morphology and zygote number from other species with bisexual spheroids in Volvox sect. Volvox. Therefore, Volvox biwakoensis Nozaki et H. Yamaguchi sp. nov. is described herein. This is the first endemic species of the genus Volvox described from an ancient lake.

Detection of mutations in the voltage-gated sodium channel gene of Varroa destructor (Acari: Varroidae) populations

The honeybee (Apis mellifera) ectoparasite, Varroa destructor, is one of the most important honeybee pests worldwide. Acaricides, including the pyrethroids (tau-fluvalinate, flumethrin), and organophosphate (coumaphos) have been applied to control this mite within apiaries, still the long-term, constant, and excessive use of these products has led to the development of resistance in many populations. Three different mutations (L925V, L925I, L925M) at position 925 and one mutation (M918L) at 918 position of the V. destructor voltage-gated sodium channel (VGSC) have been associated with the resistance to these compounds. In the present study, we examined the presence of resistance mutations in the VGSC gene, encoding the target of pyrethroids, in the V. destructor population collected from the Kayseri and Sivas provinces of Central Anatolia Region of Türkiye. A total of 200 V. destructor samples were collected from 20 apiaries in two provinces throughout 2023. To investigate the mutations in Varroa samples, the domain II region of the VGSC gene was amplified using PCR and sequenced. The nucleotide sequencing of the IIS4-IIS5 linker region of the VGSC gene revealed one amino acid change at position 925: a leucine to isoleucine substitution (L925I). No mutations at other positions were identified. Homozygous resistant alleles were detected in 20 (40 %) of the sequenced 50 samples in the study areas. However, we detected the homozygous sensitive allele (wild-type allele, L925) in the remaining samples (50/30, 60 %). The result shows that this status may indicate a problem for Varroa control in the future. Thus, alternative acaricide with a mode of action of different pyrethroids should be considered in the control of V. destructor populations in these provinces.

Patterns of microbiome composition in tsetse fly Glossina palpalis palpalis during vector control using Tiny Targets in Campo, South Cameroon.

Novel vector control tools against African trypanosomiases require a deep understanding of the factors driving tsetse vector fitness or population resilience in their ecosystems. Following evidence of microbiota-mediated host fitness or traits shaping, including insecticide resistance in arthropod populations, we undertook a comparative study of the microbiota in wild-caught tsetse flies during vector control with deltamethrin-impregnated traps called Tiny Targets. The bacterial microbiome composition of tsetse flies collected before and after 6, 12, and 18 months of vector control were characterized using high-throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene and compared. Overall, 48 bacterial genera and five phyla were identified. The primary symbiont Wigglesworthia dominated almost all the samples with an overall relative abundance of 71.76%. A significant increase was observed in microbiome diversities over the vector control with new taxa identified. Interestingly, few genera, like Curvibacter for instance, displayed a regularly increasing abundance, from 0.57% to 0.65%, 4.73%, and 8.57% after 6, 12, and 18 months of tsetse control, respectively. This study provided preliminary for further investigation into the role and mechanism of action of microbiota in tsetse fly fitness under selective pressure like insecticides.IMPORTANCEThe interest in vector control in the fight against African trypanosomiases has been reinforced in recent years, with the development of small insecticide-impregnated screens, known as "Tiny Targets". As some tsetse biotopes are difficult to access for their installation, other tools are under consideration that involve using bacteria harbored by the tsetse vector to block the development of trypanosomes or impair the tsetse's fitness in its natural environment. Several bacterial symbionts were previously described as important for tsetse fly development, and some like Burkholderia and Citrobacter also found in tsetse flies were found associated with insecticide tolerance in other arthropods. In this research, we found the bacterial genera, Curvibacter and Acinetobacter, increased in abundance in tsetse flies during vector control. These bacteria deserve further attention to determine if they can interfere with insecticides used to control tsetse fly populations.