Transfer Events Research Articles

Mitochondrial Transfer in the Neurovascular Unit, Not Only for Energy Rescue: A Systematic Review.

Despite substantial evidence highlighting molecular communication within the components of neurovascular units (NVU), the interactions at the organelle level have been insufficiently explored in recent decades. Mitochondria, for instance, beyond their traditional role as energy supply for intracellular metabolism and survival, provide a novel perspective on intercellular connections through mitochondrial transfer. These transferred mitochondria not only carry bioactive molecules but also signal to mitigate risks in both healthy and pathological conditions. In this review, we summarized mitochondrial transfer events, relevant routes, and underlying molecular mechanisms originating from diverse cell populations within NVU. We particularly focus on the therapeutic potential of this mechanism in treating central nervous system disorders, notably neurodegenerative diseases marked by mitochondrial dysfunction and then highlight the promising prospects of exogenous mitochondrial supplementation as a treatment target.

Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause, the magnetosheath and the polar cusps by remote sensing techniques. The Solar wind–Magnetosphere–Ionosphere Link Explorer (SMILE) and Lunar Environment heliospheric X-ray Imager (LEXI) missions aim to obtain soft X-ray images of near-Earth space thanks to their Soft X-ray Imager (SXI) instruments. While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission, the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft X-ray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model. The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field. We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views. We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirror mode wave structures in the magnetosheath and flux transfer events (FTEs) at the magnetopause. Our results suggest that, although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers, mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images. For instance, a local increase by 30% in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12% enhancement in the line-of-sight- and timeintegrated soft X-ray emissivity originating from this region. Likewise, a proton density increase by 14% in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%. These are likely conservative estimates, given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind. These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale, transient phenomena occurring on the dayside.

Prediction and characterization of prophages of Stenotrophomonas maltophilia reveals a remarkable phylogenetic diversity of prophages

Prophages, which enables bacterial hosts to acquire novel traits, and increase genetic variation and evolutionary innovation, are considered to be one of the greatest drivers of bacterial diversity and evolution. Stenotrophomonas maltophilia is widely distributed and one of the most important multidrug resistant bacteria in hospitals. However, the distribution and genetic diversity of S. maltophilia prophages have not been elucidated. In this study, putative prophages were predicted in S. maltophilia genomes by using virus prediction tools, and the genetic diversity and phylogeny of S. maltophilia and the prophages they harbor were further analyzed. A total of 356 prophage regions were predicted from 88 S. maltophilia genomes. Among them, 144 were intact prophages, but 77.09% of the intact prophages did not match any known phage sequences in the public database. The number of prophage carried by S. maltophilia is related to its host habitat and is an important factor affecting the size of the host genome, but it is not related to the genetic diversity of the prophage. The prediction of auxiliary genes encoded by prophage showed that antibiotic resistance genes was not predicted for any of the prophages except for one questionable prophage, while 53 virulence genes and 169 carbohydrate active enzymes were predicted from 11.24 and 44.1% prophages, respectively. Most of the prophages (72.29%) mediated horizontal gene transfer of S. maltophilia genome, but only involved in 6.25% of the horizontal gene transfer events. In addition, CRISPR prediction indicated 97.75% S. maltophilia strains contained the CRISPR-Cas system containing 818 spacer sequences. However, these spacer sequences did not match any known S. maltophilia phages, and only a few S. maltophilia prophages. Comparative genomic analysis revealed a highly conserved and syntenic organization with genomic rearrangement between the prophages and the known related S. maltophilia phages. Our results indicate a high prevalence and genetic diversity of prophages in the genome of S. maltophilia, as well as the presence of a large number of uncharacterized phages. It provides an important complement to understanding the diversity and biological characteristics of phages, as well as the interactions and evolution between bacteria and phages.

Predicting Redox Potentials of Flow Battery-Relevant Model Electrolytes

Redox flow batteries (RFBs) are rapidly gaining traction among large-scale storage solutions for intermittent renewable energy. Given the anticipated global scale of this technology, there is an intensive ongoing search for active electrolyte species containing all earth-abundant elements. Potential RFB actives must satisfy several criteria to maximize battery performance, namely, high solubility in the RFB solvent, optimum reduction potential, and chemical stability in all redox states. Given the near infinite possible molecular combinations of the primary atoms C, H, N, O, S, and Fe, computational chemistry is an invaluable tool to accelerate the discovery of promising new RFB active compounds.Towards that end, we performed DFT calculations on two major systems: iron(III/II) tris-2,2’-bipyridine, [Fe(bpy)3]3+/2+, as a model organometallic species, and azoles as a class of small, aromatic organic compounds. For [Fe(bpy)3]3+/2+, after extensive benchmarking of various functionals, basis sets, and other parameters, we accurately predict this complex’s one-electron reduction potential. The computational protocols employed on this system serve to open up the entire class or organometallics to predictive DFT calculations for future high-throughput screening. We also performed frequency calculations in the construction of a potential energy surface of [Fe(bpy)3]3+/2+’s degradation products, with consideration of all possible spin states, during this species’ hydrolysis-initiated dimerization to µ-O-[Fe(III)(bpy)2(H2O)]2 4+. The PES is discussed in light of literature-reported mechanisms for this system.Our study on functionalized azole compounds is motivated by recent demonstrations of azo compounds for RFBs in both aqueous and non-aqueous configurations. The azo group and its related nitro to amino group-containing monomeric species offers a plethora of potentially reversible redox transformations. Here, we investigate the redox potential and solvation energies of six azole-based compounds via DFT. Amino/nitro-functionalized azoles are small, aromatic compounds with the possibility to store up to six electrons per core, which would afford unprecedented energy densities in RFBs. The findings identify several species along the nitro-azo-amino pathway that have favorable redox potentials as anolyte or catholyte species (Fig. 1), as well as potentially high water solubility. Such coupling of anolyte-catholyte species from the same class of compounds would afford a crossover-proof RFB configuration analogous to vanadium systems that has not been demonstrated for aqueous organic flow batteries. Moreover, redox potentials between cis and trans isomers of the azo species were quantified, implicating further utility of these compounds in photo-mediated cells. These results will guide experimental investigations into the feasibility of implementing azole compounds for RFBs.Figure 1. Calculated redox potentials (Latimer diagram) for various azoles, including monomeric (nitro-nitroso-hydroxylamine-amino) and dimeric (azo-type) electron transfer events. Species falling outside the -0.5 to 0.5 V range (dotted lines) implicate their potential viability as RFB anolyte (V<-0.5) or catholyte (V>0.5) redox couples. Potentials were derived from DFT-level frequency calculations (free energies) utilizing the TPSS functional, def2-TZVPP basis set, and implicit solvation (CPCM H2O, vacuum- and solvent-optimized geometries). Figure 1

Identifying and characterizing short-term drought with rapid onset based on the SAPEI in the Yangtze River basin

Study regionThe Yangtze River basin (YRB) Study focusThis study presented a methodology for identifying short-term drought events, with a particular emphasis on rapid onset. The standardized antecedent precipitation evapotranspiration index (SAPEI) was adopted to detect drought at the grid level within a time series dataset, and a clustering algorithm was employed to identify drought events with three-dimensional structures, followed by a comprehensive analysis of their spatiotemporal characteristics and the factors contributing to spatial heterogeneity. New hydrological insights for the regionsThe proposed method effectively captures the rapid intensification phase and the drought development processes. Short-term drought with rapid onset was predominantly observed in the northwestern region and the middle to lower reaches of the YRB from 1960 to 2014, exhibiting mild and moderate drought conditions. This spatial variability was related to the interactions among temperature, potential evapotranspiration, precipitation and wind. Furthermore, a total of 246 three-dimensional drought events were identified in the YRB. Among these events, centroid no-transfer events were prevalent, and the primary migration direction for centroid transfer events was from southeast to northwest. Additionally, short-term drought events displayed a characteristic evolution pattern, with the affected area remaining relatively stable while drought intensity exhibited a significant decrease which indicated the drought rapidly developed into more severe drought condition. This study can provide a reference for early warning and monitoring of short-term drought with rapid onset.

How the physicochemical substrate properties can influence the deposition of blood and seminal deposits

A comprehensive investigation into the impact of the physical and chemical variables of a substrate on the deposition was conducted to aid in the estimation of the subsequent transfer probabilities of blood and semen. The study focussed on surface roughness, topography, surface free energy (SFE), wettability, and the capacity for protein adsorption. Conjointly, evaluations of the physical and chemical characteristics of blood and seminal deposits were conducted, to assess the fluid dynamics of these non-Newtonian fluids and their adhesion potential to aluminium and polypropylene. A linear range of surface roughness parameters (0.5 – 3.5 µm) were assessed for their impact on the deposit deposition spread and adhesion height, to gather insight into the change in fluid dynamics of non-Newtonian fluids. Blood has shown to produce a uniform adhesion coverage on aluminium across all roughness categories while blood deposited on polypropylene exhibited a strong hydrophobic response from a surface roughness of 2.0 µm and beyond. Interestingly, the deposition height of blood resulted in near identical values, whether deposited onto the hydrophobic polypropylene or the hydrophilic aluminium substrate, illustrating the potential influence of a heightened fibrinogen adsorption effect. Semen deposited on aluminium resulted in concentrated localised deposition regions after reaching a surface roughness of 2.0 µm, highlighting the development of crystal formations afforded by the sodium ion concentration in the seminal fluid. The semen deposited on polypropylene conformed to the substrate contours producing a deposition film that was smoother than the substrate itself, underlining the effects of thixotropic fluid dynamics. Variables identified here establish the complexity observed for non-Newtonian fluids, and the effect protein adsorption may have on the deposition behaviour of blood and seminal deposits and inform questions in relation to the adhesion strength of said deposits and their ability to dislodge (becoming detached upon the application of an external force) from the substrate surface during a potential transfer event.

Synergistic horizontal transfer of antibiotic resistance genes and transposons in the infant gut microbial genome.

Transposons, plasmids, bacteriophages, and other mobile genetic elements facilitate horizontal gene transfer in the gut microbiota, allowing some pathogenic bacteria to acquire antibiotic resistance genes (ARGs). Currently, the relationship between specific ARGs and specific transposons in the comprehensive infant gut microbiome has not been elucidated. In this study, ARGs and transposons were annotated from the Unified Human Gastrointestinal Genome (UHGG) and the Early-Life Gut Genomes (ELGG). Association rules mining was used to explore the association between specific ARGs and specific transposons in UHGG, and the robustness of the association rules was validated using the external database in ELGG. Our results suggested that ARGs and transposons were more likely to be relevant in infant gut microbiota compared to adult gut microbiota, and nine robust association rules were identified, among which Klebsiella pneumoniae, Enterobacter hormaechei_A, and Escherichia coli_D played important roles in this association phenomenon. The emphasis of this study is to investigate the synergistic transfer of specific ARGs and specific transposons in the infant gut microbiota, which can contribute to the study of microbial pathogenesis and the ARG dissemination dynamics.IMPORTANCEThe transfer of transposons carrying antibiotic resistance genes (ARGs) among microorganisms accelerates antibiotic resistance dissemination among infant gut microbiota. Nonetheless, it is unclear what the relationship between specific ARGs and specific transposons within the infant gut microbiota. K. pneumoniae, E. hormaechei_A, and E. coli_D were identified as key players in the nine robust association rules we discovered. Meanwhile, we found that infant gut microorganisms were more susceptible to horizontal gene transfer events about specific ARGs and specific transposons than adult gut microorganisms. These discoveries could enhance the understanding of microbial pathogenesis and the ARG dissemination dynamics within the infant gut microbiota.

IS26 drives the dissemination of bla CTX-M genes in an Ecuadorian community.

The horizontal gene transfer events are the major contributors to the current spread of CTX-M-encoding genes, the most common extended-spectrum β-lactamase (ESBL), and many clinically crucial antimicrobial resistance (AMR) genes. This study presents evidence of the critical role of IS26 transposable element for the mobility of bla CTX-M gene among Escherichia coli isolates from children and domestic animals in the community. We suggest that the nucleotide sequences of IS26-bla CTX-M could be used to study bla CTX-M transmission between humans, domestic animals, and the environment, because understanding of the dissemination patterns of AMR genes is critical to implement effective measures to slow down the dissemination of these clinically important genes.

Lifestyle changes in Botryosphaeriaceae as evidenced by ancestral genome expansion and horizontal gene transfer

AbstractBotryosphaeriaceae (Botryosphaeriales, Dothideomycetes, Ascomycota) encompasses commonly encountered opportunistic pathogens that cause stem cankers on woody plants. Lifestyles of Botryosphaeriaceae species could vary as endophytes, pathogens and saprobes and one species can have one or more lifestyles. Therefore, this family is an excellent candidate to study the relationships among lifestyles and lifestyle changes. It is postulated that this family has saprobic ancestors, and the mechanisms by which they evolved from nonpathogenic ancestors to woody pathogens remain unclear. Here, we present an analysis of 18 Botryosphaeriaceae genomes, including four newly generated high-quality genomes of Botryosphaeriaceae strains. We compared Botryosphaeriaceae genomes with phylogenetically closely related Dothideomycetes taxa including plant pathogens and saprobes which revealed significant net gene family expansion in Botryosphaeriaceae. This gene expansion is prominent in the early ancestors before the divergence of genera of Botryosphaeriaceae. This expansion affected the pathogenicity-related genes and detoxification genes. Furthermore, we analysed horizontal gene transfer, which is a mechanism of transfer to genetic material between organisms that are not in a parent–offspring relationship and identified widespread putative intra-kingdom horizontal gene transfer events in this family. Most were transferred during the evolution of ancient ancestors of Botryosphaeriaceae, before the divergence of the modern genera and were enriched in pathogenicity-related genes and detoxification genes. Furthermore, The RNA sequencing analysis of the Botryosphaeriaceae species Lasiodiplodia theobromae revealed that pathogenicity-related genes and detoxification genes, including those obtained through gene family expansion and horizontal gene transfers, were significantly induced after the infection of plant hosts rather than before infection. These insights reveal critical roles for gene family expansion and horizontal gene transfers in the evolutionary adaptation of Botryosphaeriaceae in the infection of woody plants. We postulate that the pathogenic lifestyle of Botryosphaeriaceae species evolved from saprobic or endophytic lifestyles in the early divergence of this family. However, there are few endophytic genomes available for closely related species of Botryosphaeriaceae, thus further studies are necessary to clarify the evolutionary relationships of the endophytes.

Subinhibitory antibiotic concentrations promote the excision of a genomic island carried by the globally spread carbapenem-resistant Klebsiella pneumoniae sequence type 258.

The ICEKp258.2 genomic island (GI) has been proposed as an important factor for the emergence and success of the globally spread carbapenem-resistant Klebsiella pneumoniae sequence type (ST) 258. However, a characterization of this horizontally acquired element is lacking. Using bioinformatic and experimental approaches, we found that ICEKp258.2 is not confined to ST258 and ST512, but also carried by ST3795 strains and emergent invasive multidrug-resistant pathogens from ST1519. We also identified several ICEKp258.2-like GIs spread among different K. pneumoniae STs, other Klebsiella species and even other pathogen genera, uncovering horizontal gene transfer events between different STs and bacterial genera. Also, the comparative and phylogenetic analyses of the ICEKp258.2-like GIs revealed that the most closely related ICEKp258.2-like GIs were harboured by ST11 strains. Importantly, we found that subinhibitory concentrations of antibiotics used in treating K. pneumoniae infections can induce the excision of this GI and modulate its gene expression. Our findings provide the basis for the study of ICEKp258.2 and its role in the success of K. pneumoniae ST258. They also highlight the potential role of antibiotics in the spread of ICEKp258.2-like GIs among bacterial pathogens.

Eukaryotic CD-NTase, STING, and viperin proteins evolved via domain shuffling, horizontal transfer, and ancient inheritance from prokaryotes.

Animals use a variety of cell-autonomous innate immune proteins to detect viral infections and prevent replication. Recent studies have discovered that a subset of mammalian antiviral proteins have homology to antiphage defense proteins in bacteria, implying that there are aspects of innate immunity that are shared across the Tree of Life. While the majority of these studies have focused on characterizing the diversity and biochemical functions of the bacterial proteins, the evolutionary relationships between animal and bacterial proteins are less clear. This ambiguity is partly due to the long evolutionary distances separating animal and bacterial proteins, which obscures their relationships. Here, we tackle this problem for 3 innate immune families (CD-NTases [including cGAS], STINGs, and viperins) by deeply sampling protein diversity across eukaryotes. We find that viperins and OAS family CD-NTases are ancient immune proteins, likely inherited since the earliest eukaryotes first arose. In contrast, we find other immune proteins that were acquired via at least 4 independent events of horizontal gene transfer (HGT) from bacteria. Two of these events allowed algae to acquire new bacterial viperins, while 2 more HGT events gave rise to distinct superfamilies of eukaryotic CD-NTases: the cGLR superfamily (containing cGAS) that has since diversified via a series of animal-specific duplications and a previously undefined eSMODS superfamily, which more closely resembles bacterial CD-NTases. Finally, we found that cGAS and STING proteins have substantially different histories, with STING protein domains undergoing convergent domain shuffling in bacteria and eukaryotes. Overall, our findings paint a picture of eukaryotic innate immunity as highly dynamic, where eukaryotes build upon their ancient antiviral repertoires through the reuse of protein domains and by repeatedly sampling a rich reservoir of bacterial antiphage genes.

Complete mitochondrial genome of the endangered Prunus pedunculata (Prunoideae, Rosaceae) in China: characterization and phylogenetic analysis.

Prunus pedunculata (Prunoideae: Rosaceae), a relic shrub with strong resistance and multiple application values, is endangered in China. Extensive research had been devoted to gene expression, molecular markers, plastid genome analysis, and genetic background investigations of P. pedunculata. However, the mitochondrial genome of this species has not been systematically described, owing to the complexity of the plant mitogenome. In the present research, the complete mitochondrial genome of P. pedunculata was assembled, annotated, and characterized. The genomic features, gene content and repetitive sequences were analyzed. The genomic variation and phylogenetic analysis have been extensively enumerated. The P. pedunculata mitogenome is a circular molecule with a total length of 405,855 bp and a GC content of 45.63%, which are the smallest size and highest GC content among the known Prunus mitochondrial genomes. The mitogenome of P. pedunculata encodes 62 genes, including 34 unique protein-coding genes (PCGs, excluding three possible pseudogenes), three ribosomal RNA genes, and 19 transfer RNA genes. The mitogenome is rich in repetitive sequences, counting 112 simple sequence repeats, 15 tandem repeats, and 50 interspersed repetitive sequences, with a total repeat length of 11,793 bp, accounting for 2.91% of the complete genome. Leucine (Leu) was a predominant amino acid in PCGs, with a frequency of 10.67%, whereas cysteine (Cys) and tryptophan (Trp) were the least adopted. The most frequently used codon was UUU (Phe), with a relative synonymous codon usage (RSCU) value of 1.12. Selective pressure was calculated based on 20 shared PCGs in the mitogenomes of the 32 species, most of which were subjected to purifying selection (Ka/Ks < 1), whereas ccmC and ccmFn underwent positive selection. A total of 262 potential RNA editing sites in 26 PCGs were identified. Furthermore, 56 chloroplast-derived fragments were ascertained in the mitogenome, ranging from 30 to 858 bp, and were mainly located across IGS (intergenic spacer) regions or rRNA genes. These findings verify the occurrence of intracellular gene transfer events from the chloroplast to the mitochondria. Furthermore, the phylogenetic relationship of P. pedunculata was supported by the mitogenome data of 30 other taxa of the Rosaceae family. Understanding the mitochondrial genome characteristics of P. pedunculata is of great importance to promote comprehension of its genetic background and this study provides a basis for the genetic breeding of Prunus.

Determination of the Mycovirome of a Necrotrophic Fungus.

Next-generation sequencing (NGS) of total RNA has allowed the detection of novel viruses infecting different hosts, such as fungi, increasing our knowledge on virus horizontal transfer events among different hosts, virus diversity, and virus evolution. Here, we describe the detailed protocols for the isolation of the plant pathogenic fungus Botrytis cinerea, from grapevine plants showing symptoms of the mold gray disease, the culture and maintenance of the isolated B. cinerea strains, the extraction of total RNA from B. cinerea strains for NGS, the bioinformatics pipeline designed and followed to detect mycoviruses in the sequenced samples, and the validation of the in silico detected mycoviruses by different approaches.

National genomic surveillance integrating standardized quantitative susceptibility testing clarifies antimicrobial resistance in Enterobacterales

Antimicrobial resistance is a global health concern; Enterobacterales resistant to third-generation cephalosporins (3GCs) and carbapenems are of the highest priority. Here, we conducted genome sequencing and standardized quantitative antimicrobial susceptibility testing of 4,195 isolates of Escherichia coli and Klebsiella pneumoniae resistant to 3GCs and Enterobacterales with reduced meropenem susceptibility collected across Japan. Our analyses provided a complete classification of 3GC resistance mechanisms. Analyses with complete reference plasmids revealed that among the blaCTX-M extended-spectrum β-lactamase genes, blaCTX-M-8 was typically encoded in highly similar plasmids. The two major AmpC β-lactamase genes were blaCMY-2 and blaDHA-1. Long-read sequencing of representative plasmids revealed that approximately 60% and 40% of blaCMY-2 and blaDHA-1 were encoded by such plasmids, respectively. Our analyses identified strains positive for carbapenemase genes but phenotypically susceptible to carbapenems and undetectable by standard antimicrobial susceptibility testing. Systematic long-read sequencing enabled reconstruction of 183 complete plasmid sequences encoding three major carbapenemase genes and elucidation of their geographical distribution stratified by replicon types and species carrying the plasmids and potential plasmid transfer events. Overall, we provide a blueprint for a national genomic surveillance study that integrates standardized quantitative antimicrobial susceptibility testing and characterizes resistance determinants.

Intrageneric structural variation in organelle genomes from the genus Dystaenia (Apiaceae): genome rearrangement and mitochondrion-to-plastid DNA transfer.

During plant evolution, intracellular DNA transfer (IDT) occurs not only from organelles to the nucleus but also between organelles. To further comprehend these events, both organelle genomes and transcriptomes are needed. In this study, we constructed organelle genomes and transcriptomes for two Dystaenia species and described their dynamic IDTs between their nuclear and mitochondrial genomes, or plastid and mitochondrial genomes (plastome and mitogenome). We identified the putative functional transfers of the mitochondrial genes 5' rpl2, rps10, rps14, rps19, and sdh3 to the nucleus in both Dystaenia species and detected two transcripts for the rpl2 and sdh3 genes. Additional transcriptomes from the Apicaceae species also provided evidence for the transfers and duplications of these mitochondrial genes, showing lineage-specific patterns. Intrageneric variations of the IDT were found between the Dystaenia organelle genomes. Recurrent plastid-to-mitochondrion DNA transfer events were only identified in the D. takeshimana mitogenome, and a pair of mitochondrial DNAs of plastid origin (MIPTs) may generate minor alternative isoforms. We only found a mitochondrion-to-plastid DNA transfer event in the D. ibukiensis plastome. This event may be linked to inverted repeat boundary shifts in its plastome. We inferred that the insertion region involved an MIPT that had already acquired a plastid sequence in its mitogenome via IDT. We propose that the MIPT acts as a homologous region pairing between the donor and recipient sequences. Our results provide insight into the evolution of organelle genomes across the family Apiaceae.

Phylloxera and Aphids Show Distinct Features of Genome Evolution Despite Similar Reproductive Modes.

Genomes of aphids (family Aphididae) show several unusual evolutionary patterns. In particular, within the XO sex determination system of aphids, the X chromosome exhibits a lower rate of interchromosomal rearrangements, fewer highly expressed genes, and faster evolution at nonsynonymous sites compared with the autosomes. In contrast, other hemipteran lineages have similar rates of interchromosomal rearrangement for autosomes and X chromosomes. One possible explanation for these differences is the aphid's life cycle of cyclical parthenogenesis, where multiple asexual generations alternate with 1 sexual generation. If true, we should see similar features in the genomes of Phylloxeridae, an outgroup of aphids which also undergoes cyclical parthenogenesis. To investigate this, we generated a chromosome-level assembly for the grape phylloxera, an agriculturally important species of Phylloxeridae, and identified its single X chromosome. We then performed synteny analysis using the phylloxerid genome and 30 high-quality genomes of aphids and other hemipteran species. Unexpectedly, we found that the phylloxera does not share aphids' patterns of chromosome evolution. By estimating interchromosomal rearrangement rates on an absolute time scale, we found that rates are elevated for aphid autosomes compared with their X chromosomes, but this pattern does not extend to the phylloxera branch. Potentially, the conservation of X chromosome gene content is due to selection on XO males that appear in the sexual generation. We also examined gene duplication patterns across Hemiptera and uncovered horizontal gene transfer events contributing to phylloxera evolution.

Thermal Resistance of the Loop Heat Pipe Prototype in Steady State Conditions

The nuclear accident at the Fukushima Daiichi nuclear power plant in March 2011 in Japan caused a tsunami and submerged the emergency diesel generator resulting in a station blackout (SBO). Based on the accident, a study was conducted on the use of passive safety systems as a support for active safety systems in nuclear reactor cooling systems. The Loop Heat Pipe (LHP) prototype is a small-scale LHP research facility, one of which is used to determine the characteristics and heat transfer events in LHP. Calculations to determine the thermal resistance of the LHP prototype need to be carried out to determine its performance level. The research was carried out experimentally for data collection followed by calculations based on the data that had been obtained. The calculation results obtained that the lowest thermal resistance is 0.014 °C/w with a 100% filling ratio and an airflow velocity of 2.5 m/s, so the setting of filling ratio and airflow velocity produces the best LHP prototype performance. The higher the airspeed, the greater the heat released by the condenser resulting in the value of the thermal resistance of the LHP prototype getting smaller. Thus, the greater the airspeed, the lower the thermal resistance of the LHP prototype, this indicates that the performance of the LHP prototype is increasing.

Interphylum dissemination of NDM-5-positive plasmids in hospital wastewater from Fuzhou, China: a single-centre, culture-independent, plasmid transmission study

The global spread of plasmid-borne carbapenem resistance is an ongoing public health challenge; however, the nature of such horizontal gene transfer events among complex bacterial communities remains poorly understood. We examined the in-situ transfer of the globally dominant New Delhi metallo-β-lactamase (NDM)-5-positive IncX3 plasmid (denoted pX3_NDM-5) in hospital wastewater to simulate a real-world, One Health antimicrobial resistance context. For this transmission study, we tagged pX3_NDM-5 with the green fluorescent protein gene, gfp, using a CRISPR-based method and transferred the plasmid to a donor Escherichia coli strain. Bacteria were extracted from a hospital wastewater treatment plant (Fujian Provincial Maternity and Children's Hospital, Fuzhou, China) as the bacterial recipient community. We mixed this recipient community with the E coli donor strain carrying the gfp-tagged plasmid, both with and without sodium hypochlorite (NaClO) as an environmental stressor, and conducted several culture-based and culture-independent conjugation assays. The conjugation events were observed microscopically and quantified by fluorescence-activated cell sorting. We analysed the taxonomic composition of the sorted transconjugal pool by 16S rRNA gene amplicon sequencing and assessed the stability of the plasmid in the isolated transconjugants and its ability to transfer back to E coli. We show that the plasmid pX3_NDM-5 has a broad host range and can transfer across various bacterial phyla, including between Gram-negative and Gram-positive bacteria. Although environmental stress with NaClO did not affect the overall plasmid transfer frequency, it reduced the breadth of the transconjugant pool. The taxonomic composition of the transconjugal pool was distinct from that of the recipient communities, and environmental stress modulated the permissiveness of some operational taxonomic units towards the acquisition of pX3_NDM-5. Notably, pX3_NDM-5 transconjugants included the Gram-positive pathogen Enterococcus faecalis, and the plasmid could subsequently be reconjugated back to E coli. These findings suggest that E faecalis could act as a natural shuttle vector for the wide dissemination of pX3_NDM-5 plasmids. Our culture-independent conjugation model simulates natural environmental conditions and challenges the established theory that Gram-negative and Gram-positive bacteria rarely exchange clinically important plasmids. The data show that plasmids disseminate more widely across genera and phyla than previously thought. These findings have substantial implications when considering the spread of antimicrobial resistance across One Health sectors. The Laboratory of Lingnan Modern Agriculture Project, the National Natural Science Foundation of China, the Natural Science Foundation of Fujian Province of China, and the Outstanding Young Research Talents Program of Fujian Agriculture and Forestry University.

Molecular and cellular characterization of four putative nucleotide transporters from the shrimp microsporidian Enterocytozoon hepatopenaei (EHP)

Microsporidia are obligate intracellular parasites that lost several enzymes required in energy production. The expansion of transporter families in these organisms enables them to hijack ATP from hosts. In this study, nucleotide transporters of the microsporidian Enterocytozoon hepatopenaei (EHP), which causes slow growth in economically valuable Penaeus shrimp, were characterized. Analysis of the EHP genome suggested the presence of four putative nucleotide transporter genes, namely EhNTT1, EhNTT2, EhNTT3, and EhNTT4. Sequence alignment revealed four charged amino acids that are conserved in previously characterized nucleotide transporters. Phylogenetic analysis suggested that EhNTT1, 3, and 4 were derived from one horizontal gene transfer event, which was independent from that of EhNTT2. Localization of EhNTT1 and EhNTT2 using immunofluorescence analysis revealed positive signals within the envelope of developing plasmodia and on mature spores. Knockdown of EhNTT2 by double administration of sequence specific double-stranded RNA resulted in a significant reduction in EHP copy numbers, suggesting that EhNTT2 is crucial for EHP replication in shrimp. Taken together, the insight into the roles of NTTs in microsporidian proliferation can provide the biological basis for the development of alternative control strategies for microsporidian infection in shrimp.

The F pilus serves as a conduit for the DNA during conjugation between physically distant bacteria.

Horizontal transfer of F-like plasmids by bacterial conjugation is responsible for disseminating antibiotic resistance and virulence determinants among pathogenic Enterobacteriaceae species, a growing health concern worldwide. Central to this process is the conjugative F pilus, a long extracellular filamentous polymer that extends from the surface of plasmid donor cells, allowing it to probe the environment and make contact with the recipient cell. It is well established that the F pilus can retract to bring mating pair cells in tight contact before DNA transfer. However, whether DNA transfer can occur through the extended pilus has been a subject of active debate. In this study, we use live-cell microscopy to show that while most transfer events occur between cells in direct contact, the F pilus can indeed serve as a conduit for the DNA during transfer between physically distant cells. Our findings enable us to propose a unique model for conjugation that revises our understanding of the DNA transfer mechanism and the dissemination of drug resistance and virulence genes within complex bacterial communities.