Developmental Cycle Research Articles

Potato (Solanum tuberosum) as a New Host for Pentastiridius leporinus (Hemiptera: Cixiidae) and Candidatus Arsenophonus Phytopathogenicus

Pentastiridius leporinus is a planthopper (Hemiptera: Cixiidae) that vectors two phloem-restricted bacterial pathogens to sugar beet (Beta vulgaris (L.)): the γ-proteobacterium Candidatus Arsenophonus phytopathogenicus and the stolbur phytoplasma Candidatus Phytoplasma solani. These bacteria cause an economically important disease known as syndrome basses richesses (SBR), characterized by yellowing, deformed leaves and low beet yields. Having observed potato fields in Germany infested with cixiid planthoppers and showing signs of leaf yellowing, we used morphological criteria and COI and COII as molecular markers, to identify the planthoppers (adults and nymphs) primarily as P. leporinus. We analyzed planthoppers, potato tubers, and sugar beet roots and detected both pathogens in all sample types, confirming that P. leporinus adults and nymphs can transmit the bacteria. This is the first time that P. leporinus has been shown to transmit Arsenophonus to potato plants. We also found that two generations of P. leporinus were produced in the warm summer of 2022, which will probably increase the pest population size (and thus the prevalence of SBR) in 2023. We conclude that P. leporinus has expanded its host range to potato, and can now utilize both host plants during its developmental cycle, a finding that will facilitate the development of more efficient control strategies.

Homologues of the Chlamydia trachomatis and Chlamydia muridarum Inclusion Membrane Protein IncS Are Interchangeable for Early Development but Not for Inclusion Stability in the Late Developmental Cycle.

Chlamydia trachomatis is an obligate intracellular bacterium, which undergoes a biphasic developmental cycle inside a vacuole termed the inclusion. Chlamydia-specific effector proteins embedded into the inclusion membrane, the Inc proteins, facilitate inclusion interaction with cellular organelles. A subset of Inc proteins engages with specific host factors at the endoplasmic reticulum (ER)-inclusion membrane contact site (MCS), which is a discrete point of contact between the inclusion membrane and the endoplasmic reticulum (ER). Here, we report that the C. trachomatis Inc protein CTL0402/IncSCt is a novel component of the ER-inclusion MCS that specifically interacts with and recruits STIM1, a previously identified host component of the ER-inclusion MCS with an unassigned interacting partner at the inclusion membrane. In comparison, the Chlamydia muridarum IncS homologue (TC0424/IncSCm) does not interact with or recruit STIM1 to the inclusion, indicating species specificity. To further investigate IncS function and overcome the recently reported early developmental defect of the incS mutant, we achieved temporal complementation by expressing IncS exclusively during the early stages of the developmental cycle. Additionally, we used allelic exchange to replace the incSCt open reading frame with incSCm in the C. trachomatis chromosome. Inclusions harboring either of these strains progressed through the developmental cycle but were STIM1 negative and displayed increased inclusion lysis 48 h postinfection. Expression of incSCt in trans complemented these phenotypes. Altogether, our results indicate that IncS is necessary and sufficient to recruit STIM1 to C. trachomatis inclusion and that IncS plays an early developmental role conserved in C. trachomatis and C. muridarum and a late role in inclusion stability specific to C. trachomatis. IMPORTANCE Obligate intracellular pathogens strictly rely on the host for replication. Specialized pathogen-encoded effector proteins play a central role in sophisticated mechanisms of host cell manipulation. In Chlamydia, a subset of these effector proteins, the inclusion membrane proteins, are embedded in the membrane of the vacuole in which the bacteria replicate. Chlamydia encodes 50 to 100 putative Inc proteins. Many are conserved among species, including the human and mouse pathogens Chlamydia trachomatis and Chlamydia muridarum, respectively. However, whether the function(s) of Inc proteins is indeed conserved among species is poorly understood. Here, we characterized the function of the Inc protein IncS conserved in C. trachomatis and C. muridarum. Our work reveals that a single effector protein can play multiple functions at various stages of the developmental cycle. However, these functions are not necessarily conserved across species, suggesting a complex evolutionary path among Chlamydia species.

A Survey of Two-Component Systems in Coxiella burnetii Reveals Redundant Regulatory Schemes and a Requirement for an Atypical PhoBR System in Mammalian Cell Infection.

Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever in humans. C. burnetii transitions between a replicative, metabolically active large-cell variant (LCV) and a spore-like, quiescent small-cell variant (SCV) as a likely mechanism to ensure survival between host cells and mammalian hosts. C. burnetii encodes three canonical two-component systems, four orphan hybrid histidine kinases, five orphan response regulators, and a histidine phosphotransfer protein, which have been speculated to play roles in the signaling required for C. burnetii morphogenesis and virulence. However, very few of these systems have been characterized. By employing a CRISPR interference system for genetic manipulation of C. burnetii, we created single- and multigene transcriptional knockdown strains targeting most of these signaling genes. Through this, we revealed a role for the C. burnetii PhoBR canonical two-component system in virulence, regulation of [Pi] maintenance, and Pi transport. We also outline a novel mechanism by which PhoBR function may be regulated by an atypical PhoU-like protein. We also determined that the GacA.2/GacA.3/GacA.4/GacS orphan response regulators coordinately and disparately regulate expression of SCV-associated genes in C. burnetii LCVs. These foundational results will inform future studies on the role of C. burnetii two-component systems in virulence and morphogenesis. IMPORTANCE C. burnetii is an obligate intracellular bacterium with a spore-like stability allowing it to survive long periods of time in the environment. This stability is likely due to its biphasic developmental cycle, whereby it can transition from an environmentally stable small-cell variant (SCV) to a metabolically active large-cell variant (LCV). Here, we define the role of two-component phosphorelay systems (TCS) in C. burnetii's ability to survive within the harsh environment contained in the phagolysosome of host cells. We show that the canonical PhoBR TCS has an important role in C. burnetii virulence and phosphate sensing. Further examination of the regulons controlled by orphan regulators indicated a role in modulating gene expression of SCV-associated genes, including genes essential for cell wall remodeling.

Rozwijanie zdolności samodzielnego uczenia się − redefinicja myślenia o gotowości szkolnej dziecka w kontekście kulturowo-historycznej teorii Lwa S. Wygotskiego

The quality of a child’s start at school is determined by his or her level of school readiness, readiness (sensitivity) to master the basic tools of participation in culture (reading, writing, counting). School readiness procedures usually involve diagnostic tools that focus on completed developmental cycles which provide an indicator of ongoing performance. They focus on what the child already knows and what he or she can do on his or her own. The article discusses the problem of school readiness in the context of Lev S. Vygotsky’s sociocultural theory. This perspective introduces a new thread and raises new questions about the old problem of school readiness. It focuses on thinking about school readiness as not being fully developed before starting school. It involves the readiness to responsive learning, developing the ability to learn independently, self-regulation, conscious control, and the ability to follow the teacher’s instructions. Developing school readiness in a sociocultural cultural approach means developing resources and competences for independent and responsible learning. Supporting the development of readiness may also mean equipping the child with tools that allow him or her to understand the school situation, meaning making processes, building relationships with others and developing coping skills and strategies. The diagnosis of readiness understood in this way is focused on the area of the child’s Zone of Proximal Development and exploring the child’s learning potential as well as his or her readiness to follow the teacher’s instructions. Keywords: school readiness, responsive learning, developing independent learning, activity learning, self-regulated learning, Lev S. Vygotsky’s theory, the social situation of development.

Decomposition of yield gap of soybean in environment × genetics × management in Southern Brazil

Estimates and explanations of yield gaps make it possible to increase crop production through improvements in agricultural systems and better crop management. The combination of field data and crop modeling allows scaling the efforts needed to close the yield gap. The objective of this study was to decompose the soybean yield gap into its constituents and to quantify the influence of the main limiting factors on soybean yield in Rio Grande do Sul, Brazil. Yield potentials and water-limited yield potentials were estimated by the CSM-CROPGRO soybean simulation model to quantify the yield gaps related to the choice of cultivar and sowing time, water gap, and gap related to other management practices. We used data from a survey of 853 fields reported by farmers over four growing seasons to quantify yield gaps for each field and the influence of management practices on soybean yields. The annual increase in soybean yield in RS depends on improvements in management (44 %), genetic breeding (42 %) and climate changes (14 %). We identified a gap of 995 kg ha−1 attributed to the choice of cultivar and sowing date, 2006 kg ha−1 attributed to water availability during the developmental cycle and 1437 kg ha−1 attributed to management improvements. A yield gap of 2432 kg ha−1 (genotype × environment gap and management gap) can be closed with adjustments in management practices such as choosing the best cultivar, sowing date, soil pH, P2O5 and K2O fertilization, no-tillage, and summer and winter crop rotation.

Detailed chemical analysis of honey bee (Apis mellifera) worker brood volatile profile from egg to emergence.

Chemical communication is a widely used mode of communication for social insects and has been demonstrated to be involved in many behaviours and physiological processes such as reproduction, nutrition or the fight against parasites and pathogens. In the honey bee, Apis mellifera, the release of chemical compounds by the brood plays a role in worker behaviour, physiology, and foraging activities and colony health as a whole. Several compounds have already been described as brood pheromones, such as components of the brood ester pheromone and (E)-β-ocimene. Several other compounds originating from diseased or varroa-infested brood cells have been described as triggering the hygienic behaviour of workers. So far, studies of brood emissions have focused on specific stages of development and little is known about the emission of volatile organic compounds by the brood. In this study, we investigate the semiochemical profile of worker honey bee brood during its whole developmental cycle, from egg to emergence, with a specific focus on volatile organic compounds. We describe variation in emissions of thirty-two volatile organic compounds between brood stages. We highlight candidate compounds that are particularly abundant in specific stages and discuss their potential biological significance.

Metabolic responses in blood-stage malaria parasites associated with increased and decreased sensitivity to PfATP4 inhibitors

BackgroundSpiroindolone and pyrazoleamide antimalarial compounds target Plasmodium falciparum P-type ATPase (PfATP4) and induce disruption of intracellular Na+ homeostasis. Recently, a PfATP4 mutation was discovered that confers resistance to a pyrazoleamide while increasing sensitivity to a spiroindolone. Transcriptomic and metabolic adaptations that underlie this seemingly contradictory response of P. falciparum to sublethal concentrations of each compound were examined to understand the different cellular accommodation to PfATP4 disruptions.MethodsA genetically engineered P. falciparum Dd2 strain (Dd2A211V) carrying an Ala211Val (A211V) mutation in PfATP4 was used to identify metabolic adaptations associated with the mutation that results in decreased sensitivity to PA21A092 (a pyrazoleamide) and increased sensitivity to KAE609 (a spiroindolone). First, sublethal doses of PA21A092 and KAE609 causing substantial reduction (30–70%) in Dd2A211V parasite replication were identified. Then, at this sublethal dose of PA21A092 (or KAE609), metabolomic and transcriptomic data were collected during the first intraerythrocytic developmental cycle. Finally, the time-resolved data were integrated with a whole-genome metabolic network model of P. falciparum to characterize antimalarial-induced physiological adaptations.ResultsSublethal treatment with PA21A092 caused significant (p < 0.001) alterations in the abundances of 91 Plasmodium gene transcripts, whereas only 21 transcripts were significantly altered due to sublethal treatment with KAE609. In the metabolomic data, a substantial alteration (≥ fourfold) in the abundances of carbohydrate metabolites in the presence of either compound was found. The estimated rates of macromolecule syntheses between the two antimalarial-treated conditions were also comparable, except for the rate of lipid synthesis. A closer examination of parasite metabolism in the presence of either compound indicated statistically significant differences in enzymatic activities associated with synthesis of phosphatidylcholine, phosphatidylserine, and phosphatidylinositol.ConclusionThe results of this study suggest that malaria parasites activate protein kinases via phospholipid-dependent signalling in response to the ionic perturbation induced by the Na+ homeostasis disruptor PA21A092. Therefore, targeted disruption of phospholipid signalling in PA21A092-resistant parasites could be a means to block the emergence of resistance to PA21A092.

Eukaryotic Clathrin Adapter Protein and Mediator of Cholesterol Homeostasis, PICALM, Affects Trafficking to the Chlamydial Inclusion.

The obligate intracellular pathogen Chlamydia trachomatis has unique metabolic requirements as it proceeds through its biphasic developmental cycle from within the inclusion within the host cell. In our previous study, we identified a host protein, PICALM, which localizes to the chlamydial inclusion. PICALM functions in many host pathways including the recycling of receptors, specific SNARE proteins, and molecules like transferrin, and maintaining cholesterol homeostasis. Hence, we hypothesized that PICALM functions to maintain the cholesterol content and to moderate trafficking from the endosomal recycling pathway to the inclusion, which controls chlamydial access to this pathway. In uninfected cells, siRNA knockdown of PICALM resulted in increased cholesterol within the Golgi and transferrin receptor (TfR) positive vesicles (recycling endosomes). PICALM knockdown in cells infected with C. trachomatis resulted in increased levels of Golgi-derived lipid and protein, TfR, transferrin, and Rab11-FIP1 localized to inclusions and a decrease of Golgi fragmentation at and Rab11 trafficking to the inclusion. Interestingly, chlamydial infection alone also increases cholesterol in TfR and Rab11-associated vesicles, and PICALM knockdown reverses this effect. Our data suggest that PICALM functions to balance or limit chlamydial access to multiple subcellular trafficking pathways to maintain the health of the host cell during chlamydial infection.

A rising tide of parasite transcriptomics propels pathogen biology.

Twenty years ago, the first transcriptome of the intraerythrocytic developmental cycle of the malaria parasite Plasmodium falciparum was published in PLOS Biology. Since then, transcriptomics studies have transformed the study of parasite biology.

TargeTron inactivation of plasmid-regulated Chlamydia trachomatis CT084 results in a nonlytic phenotype.

Chlamydia trachomatis is an obligate intracellular bacterium that causes blinding trachoma and sexually transmitted disease. The chlamydial plasmid is a critical virulence factor in the pathogenesis of these diseases. Plasmid gene protein 4 (Pgp4) plays a major role in chlamydial virulence by regulating the expression of both chromosomal genes and Pgp3. Despite the importance of Pgp4 in mediating lytic exit from host cells the pathogenic mechanism by which it functions is unknown. CT084 is a highly conserved chromosomal gene with homology to phospholipase D. We showed CT084 expression is regulated by Pgp4 and expressed late in the chlamydial developmental cycle. To investigate the function of CT084 in chlamydial lytic exit from infected cells, we made a CT084 null strain (ct084::bla) by using Targetron. The ct084::bla strain grew normally in vitro compared to wild-type strain; however, the strain did not lyse infected cells and produced significantly less and smaller plaques. Collectively, our finding shows Pgp4-regulated CT084-mediated chlamydia lytic exit from infected host cells.

Comparison of the chronic and multigenerational toxicity of racemic glufosinate and l-glufosinate to Caenorhabditis elegans at environmental concentrations

Glufosinate-ammonium, the second largest transgene crop resistant herbicide, is classified as a mobile persistent pollutant by the U.S. Environmental Protection Agencybecause of its slow decomposition and easy mobile transfer in a water environment. The chronic and multigeneration toxicity of this compound to environmental organisms are alarming. In this study, racemic glufosinate-ammonium and the effective isomer, l-glufosinate-ammonium, were used as the test agents. The developmental, neurotoxic and reproductive toxicities of Caenorhabditis elegans to their parents and progeny were studied by continuous exposure in water at concentrations of 0.1, 1, 10 and 100 μg/L. The causes of toxicity differences were analysed from oxidative stress and transcription levels. Through oxidative stress of C. elegans, racemic glufosinate-ammonium and l-glufosinate-ammonium both mediated the developmental toxicity (shortened developmental cycle, reduced body length and width, promoted ageingand decreased longevity), neurotoxicity (inhibited head swinging, body bending frequency and acetylcholinesterase [AchE] activity) and reproductive toxicity (significant reductions in the number of eggs and offspring in vivo and induced apoptosis of gonadal cells). These phenomena caused oxidative damage (protein and membrane lipid peroxidation) and further induced apoptosis. The changes in various indicators caused by racemic glufosinate-ammonium exposure were more significant than those caused by l-glufosinate-ammonium exposure, and the reproduction-related indicators were more significant than the developmental and neurological indicators. A continuous accumulation of toxicity was observed after multiple generations of continuous exposure. These research results provide a data reference for the ecotoxicological evaluation and risk assessment of glufosinate-ammonium and contribute to the revision and improvement of the related environmental policies of glufosinate-ammonium.

Above- and below-ground microbiome in the annual developmental cycle of two olive tree varieties.

The olive tree is a hallmark crop in the Mediterranean region. Its cultivation is characterized by an enormous variability in existing genotypes and geographical areas. As regards the associated microbial communities of the olive tree, despite progress, we still lack comprehensive knowledge in the description of these key determinants of plant health and productivity. Here, we determined the prokaryotic, fungal and arbuscular mycorrhizal fungal (AMF) microbiome in below- (rhizospheric soil, roots) and above-ground (phyllosphere and carposphere) plant compartments of two olive varieties 'Koroneiki' and 'Chondrolia Chalkidikis' grown in Southern and Northern Greece respectively, in five developmental stages along a full fruit-bearing season. Distinct microbial communities were supported in above- and below-ground plant parts; while the former tended to be similar between the two varieties/locations, the latter were location specific. In both varieties/locations, a seasonally stable root microbiome was observed over time; in contrast the plant microbiome in the other compartments were prone to changes over time, which may be related to seasonal environmental change and/or to plant developmental stage. We noted that olive roots exhibited an AMF-specific filtering effect (not observed for bacteria and general fungi) onto the rhizosphere AMF communities of the two olive varieties/locations/, leading to the assemblage of homogenous intraradical AMF communities. Finally, shared microbiome members between the two olive varieties/locations include bacterial and fungal taxa with putative functional attributes that may contribute to olive tree tolerance to abiotic and biotic stress.

Predictive Model of Humidity in Greenhouses through Fuzzy Inference Systems Applying Optimization Methods

Establishing the indoor and outdoor humidity values in a greenhouse allows us to describe the crop yield during its entire developmental cycle. This study seeks to develop a predictive model of indoor relative humidity values in a greenhouse with high accuracy and interpretability through the use of optimized fuzzy inference systems, in order to offer greenhouse users a clear and simple description of their behaviour. The three-phase methodology applied made use of descriptive statistics techniques, correlation analysis, and prototyping paradigm for the iterative and incremental development of the predictive model, validated through error measurement. The research resulted in six models which define the behaviour of humidity as a result of temperature, CO2, and soil moisture, with percentages of effectiveness above 90%. The implementation of a Mamdani-type fuzzy inference system, optimized by a hybrid method combining genetic and interior point algorithms, allowed to predict the relative humidity in greenhouses with high interpretability and precision, with an effectiveness percentage of 90.97% and MSE (mean square error) of 8.2e − 3.

Diversity of σ66-Specific Promoters Contributes to Regulation of Developmental Gene Expression in Chlamydia trachomatis.

Promoter recognition by the RNA polymerase (RNAP) holoenzyme is a key step in gene regulation. In Chlamydia trachomatis, a medically important obligate intracellular bacterium, σ66 allows the RNAP to initiate promoter-specific transcription throughout the chlamydial developmental cycle. Here, we investigated the intrinsic properties of σ66-specific promoters with emphasis on their role in the developmental gene expression of C. trachomatis. First, we examined whether promoters that contain a 5'-T(-15)G(-14)-3' (TG) motif upstream from the -10 element appear more often than others in genes that are preferentially expressed during the early, middle, or late stages of the C. trachomatis developmental cycle. We then determined the critical genetic elements that are required for transcription initiation in vitro. We also assessed the activity of promoters in the presence of Scc4, which can directly interact with σ66RNAP. Finally, we evaluated the promoter-specific dynamics during C. trachomatis infection using a reporter assay. These results reveal that the TG motif is an important determinant in certain early or late promoters. The TG promoters that have the -35 element are recognized by σ66RNAP and Scc4 differently from those lacking the -35 element. Based on these properties, the σ66-specific promoters can fall into three classes. Architectural diversity, behavioral plasticity, and the specific interplays between promoters and the σ66RNAP likely contribute to developmental gene transcription in C. trachomatis. IMPORTANCE Meticulous promoter elucidation is required to understand the foundations of transcription initiation. However, knowledge of promoter-specific transcription remains limited in C. trachomatis. This work underscores the structural and functional plasticity of σ66-specific promoters that are regulated by σ66RNAP, as well as their importance in the developmental gene regulation of C. trachomatis.

Streptomyces development is involved in the efficient containment of viral infections.

The formation of plaques represents the hallmark of phage infection visualizing the clearance of the bacterial lawn in structured environments. In this study, we have addressed the impact of cellular development on phage infection in Streptomyces undergoing a complex developmental life cycle. Analysis of plaque dynamics revealed, after a period of plaque size enlargement, a significant regrowth of transiently phage-resistant Streptomyces mycelium into the lysis zone. Analysis of Streptomyces venezuelae mutant strains defective at different stages of cellular development indicated that this regrowth was dependent on the onset of the formation of aerial hyphae and spores at the infection interface. Mutants restricted to vegetative growth (ΔbldN) featured no significant constriction of plaque area. Fluorescence microscopy further confirmed the emergence of a distinct zone of cells/spores with reduced cell permeability towards propidium iodide staining at the plaque periphery. Mature mycelium was further shown to be significantly less susceptible to phage infection, which is less pronounced in strains defective in cellular development. Transcriptome analysis revealed the repression of cellular development at the early stages of phage infection probably facilitating efficient phage propagation. We further observed an induction of the chloramphenicol biosynthetic gene cluster highlighting phage infection as a trigger of cryptic metabolism in Streptomyces. Altogether, our study emphasizes cellular development and the emergence of transient phage resistance as an important layer of Streptomyces antiviral immunity.

Molecular detection of Cercopithifilaria, Cruorifilaria and Dipetalonema-like filarial nematodes in ticks of French Guiana.

Filarial nematodes of the Dipetalonema lineage are widespread parasites and include some species that are transmitted by ticks. In this study, we conducted a large molecular survey of ticks in French Guiana, South America, to understand the overall diversity of tick-borne filarioids in this remote region largely covered by dense tropical forests. Out of 682 ticks belonging to 22 species and 6 genera, 21 ticks (3.1%) of the species Amblyomma cajennense, A. oblongoguttatum, A. romitii, Ixodes luciae and Rhipicephalus sanguineus sensu lato were positive for infection by filarioids. Molecular typing and phylogenetic analysis identified all these filarioids as members of the Dipetalonema lineage. While the filarioid of R. sanguineus sensu lato is a previously described species, the canine worm Cercopithifilaria bainae Almeida & Vicente, 1984, all other filarioids detected in this study are related but distinct to already known species in the genera Cercopithifilaria, Cruorifilaria and Dipetalonema. Their vertebrate host range may include a wide variety of mammals present in French Guiana, but dogs, capybaras, and opossums are the best candidate hosts for some of these filarioids. Although the detection of members of the Dipetalonema lineage in ticks of significant medical or veterinary interest is of concern, the risk of contracting a tick-borne filarial infection is still largely unknown. The pathogenicity of these filarioids, their epidemiology, developmental cycles, and mechanisms of transmission by South American tick species now require further study.

Population dynamics, vertical distribution and damage characterization of burrower bug in peanut

Although the burrower bug (Cyrtomenus mirabilis) is considered a vitalsoil pest in peanut crops, Arachis hypogaea L., in South America, there is little information on its occurrence and damage characterization. This study aimed to evaluate the vertical distribution and fluctuation of the burrower bug in the soil and the damage this species causes in peanuts. Two peanut cultivars (IAC OL3 and IAC 503) were evaluated in three locations in the state of São Paulo: Pindorama, Ribeirão Preto and Votuporanga, in the 2017/18 and 2018/19 harvests. Trenches were dug 0.5 m long, 0.3 m wide and 0.3 m deep, along plant lines at four spots on each sampling date, and stratified in layers 10 cm deep. Plant samples (0.5 m) were collected and evaluated for number of pods and percentage of kernels with symptoms of insect damage. More than 85 % of the C. mirabilis population was found in depths of up to 10 cm, especially after plant fructification, and an increase in nymphs from 100 days after sowing (DAS) was seen when an increased number of maturing pods was observed. The occurrence of nymphs and adults of C. mirabilis and their damage to peanut kernels was similar in both cultivars (IAC OL3 and IAC 503), when these were harvested according to their developmental cycles.

ДИАГНОСТИКА ГЕМОПАРАЗИТОВ У PELOPHYLAX LESSONAE

This article describes the distribution, developmental cycle, clinical manifestations and diagnosis of haemoparasitic diseases in amphibians. An overview of the etiology and detection methods of haemoparasites is presented. The article presents the results of the complex clinical and laboratory examination of the series of clinical cases of haemoparasites in the experimental group of amphibians (n=6) of pond frog species Pelophylax lessonae, caught on 07.05.2022. As a control we used 5 specimens of pond frogs, caught on 02.07.2022 in the same biotope as the experimental group. Both groups were kept in artificial conditions. The experimental group was kept from 07.05.2022 to 28.07.2022, the control group was kept from 02.07.2022 to 28.07.2022. Dry peripheral blood smears were fixed with 96° ethanol and stained with Romanowsky-Giemsa (pH 6.8). Microscopic examination of blood smears of each individual of both groups revealed the presence of haemoparasites. It was found that the species composition of parasites is represented by one species - sporozooners Hepatozoon magna. By the method of calculating the extensiveness, the average intensity of invasion and the parasites abundance index found that the indicators of the experimental group were much higher than the control, the extensiveness of invasion: (83,3%, against 40%), the average intensity of invasion: (37 against 25), the parasites abundance index: (30,8 against 10). Based on the results of the studies, the dependence of the spread of haemoparasites on housing conditions and period was revealed. It has been suggested that the longer a group of individuals has been kept under artificial conditions, the higher its indices of extensiveness, average invasion intensity and parasite abundance index are.

Beta lactamase-producing Neisseria gonorrhoeae alleviates Amoxicillin-induced chlamydial persistence in a novel in vitro co-infection model

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) cause most bacterial sexually transmitted infections (STIs) worldwide. Epidemiological studies have shown high percentages of co-infections with CT/NG and indicate that NG co-infection can reactivate CT shedding during persistent chlamydial infection. These data also suggest that biological interaction between the two bacteria may increase susceptibility or transmissibility. CT is an obligate intracellular bacterium with a developmental cycle that alternates between two forms: infectious elementary bodies (EBs) which invade the epithelium and non-infectious reticulate bodies (RBs) which divide and replicate inside the inclusion. Adverse environmental conditions can interrupt chlamydial development, with a consequent temporary halt in RB division, reduction in infectious EB production and formation of enlarged chlamydiae (aberrant bodies, ABs) – characterizing chlamydial persistence. When the stressor is removed, the chlamydial developmental cycle is restored, together with production of infectious EBs. The beta-lactam amoxicillin (AMX) induces chlamydial persistence, both in vitro and in mice. We investigated the impact of penicillinase-producing NG strain (PPNG) on AMX-persistent chlamydial infection utilizing our recently developed, contact-independent in vitro model of co-infection. We hypothesized that co-infection with PPNG could prevent and/or reverse AMX-induced chlamydial persistence. Our results showed that PPNG can ameliorate AMX-persistence in two chlamydial species, CT and C. muridarum (CM), providing novel evidence for a range of Chlamydia/NG interactions.

Creating environment for students to make interdisciplinary competences in botany

The authors have developed an innovative botanical course that integrates genetic ideas into the botany curriculum. The process of choosing regional relics was conducted with the aim of illustrating the notions of full and partial dominion. This paper presents a novel phenetic approach for examining population genetic trends via the analysis of discrete alternative characteristics. In order to achieve this purpose, it is recommended to choose plant specimens from the local area that have significant morphological variety. This will allow students to actively participate in the collecting and study process during trips. The educational institution’s curriculum integrates research components and cultivates the growth of mathematical statistical skills for the purpose of conducting quantitative analysis of results. The exploitation of currently available regional objects demonstrates the concept of the law of homologous series in genetic diversity and mutagenesis in plants. One of the recommended papers provides a detailed and concentrated overview of the developmental cycles seen in the primary plant categories. The investigation of hybridization in plants is often undertaken via the examination of this phenomena over a diverse range of plant species, including both widely dispersed wild plants and cultivated varieties. These botanical specimens have the capacity to engage in crossbreeding, leading to the emergence of hybrids that may occur either naturally or by deliberate human intervention.