A pyocin-like T6SS effector mediates bacterial competition in Yersinia pseudotuberculosis.

Within the realm of Gram-negative bacteria, bacteriocins are secreted almost everywhere, and the most representative are colicin and pyocin, which are secreted by Escherichia coli and Pseudomonas aeruginosa, respectively. Signal peptides at the amino terminus of bacteriocins or ABC transporters can secrete bacteriocins, which then enter bacteria through cell membrane receptors and exert toxicity. In general, the bactericidal spectrum is usually narrow, killing only the kin or closely related species. Our previous research indicates that YPK_0952 is an effector of the third Type VI secretion system (T6SS-3) in Yersinia pseudotuberculosis. Next, we sought to determine its identity and characterize its toxicity. We found that YPK_0952 (a pyocin-like effector) can achieve intra-species and inter-species competitive advantages through both contact-dependent and contact-independent mechanisms mediated by the T6SS-3 while enhancing the intestinal colonization capacity of Y. pseudotuberculosis. We further identified YPK_0952 as a DNase dependent on Mg2+, Ni2+, Mn2+, and Co2+ bivalent metal ions, and the homologous immune protein YPK_0953 can inhibit its activity. In summary, YPK_0952 exerts toxicity by degrading nucleic acids from competing cells, and YPK_0953 prevents self-attack in Y. pseudotuberculosis.IMPORTANCEBacteriocins secreted by Gram-negative bacteria generally enter cells through specific interactions on the cell surface, resulting in a narrow bactericidal spectrum. First, we identified a new pyocin-like effector protein, YPK_0952, in the third Type VI secretion system (T6SS-3) of Yersinia pseudotuberculosis. YPK_0952 is secreted by T6SS-3 and can exert DNase activity through contact-dependent and contact-independent entry into nearby cells of the same and other species (e.g., Escherichia coli) to help Y. pseudotuberculosis to exert a competitive advantage and promote intestinal colonization. This discovery lays the foundation for an in-depth study of the different effector protein types within the T6SS and their complexity in competing interactions. At the same time, this study provides a new development for the toolbox of toxin/immune pairs for studying Gram-negative bacteriocin translocation.

Effective evaluations of community nursing on rehabilitation for stroke survivors: A meta-analysis.

BACKGROUND: Long-term rehabilitation of stroke survivors is often difficult and new tools to improve quality of life should be proposed. Community nursing can be a cost-effective tool to positively impact the lives of stroke survivors. This meta-analysis aimed to comprehensively evaluate the effects of community nursing on rehabilitation for stroke survivors. METHODS: The Cochrane Library, PubMed, Web of Science, CINAHL Plus, Embase, PEDro, China Knowledge Resource Integrated Database (CNKI), WANFANG, and WEIPU databases were comprehensively searched from their inception to April 18, 2023. The revised Cochrane risk-of-bias tool for RCTs(RoB 2 tool) was used to assess the quality of the included studies. Meta-analysis was conducted using the Stata 12.0 software package and Review Manager v5.3 software. RESULTS: A total of 25 randomized controlled trials with 2537 participants were included in the meta-analysis. Compared with the control group, community nursing combined with routine nursing had a significantly superior effect on the Barthel Index(BI), Fugl-Meyer(FMA), National Institutes of Health Stroke Scale(NIHSS), Self-rating Anxiety Scale(SAS), and Self-rating Depression Scale(SDS) scores for stroke survivors (BI: MD: 18.48, 95 % CI [16.87, 20.08], P < 0.00001; FMA: MD: 12.61, 95 % CI [10.44, 14.78], P < 0.00001; NIHSS: MD: -2.94, 95 % CI [-3.50, -2.37], P < 0.00001; SAS: MD: -8.19; 95 % CI: [-9.46, -6.92], P < 0.00001; SDS: MD: -6.46 95 % CI [-7.23, -5.70], P < 0.00001). Subgroup analysis demonstrated that routine nursing, health education, exercise rehabilitation nursing and psychological nursing combined with different community nursing measures were significant in rehabilitation for stroke survivors and there was no heterogeneous in the studies of each subgroup(P > 0.1, I2 < 50 %). CONCLUSION: This meta-analysis demonstrated that community nursing combined with routine nursing might improve activities of daily living, motor function and nerve function, and relieve anxiety and depression in stroke survivors. Overall, community nursing had a significant effect on rehabilitation of stroke survivors. However, this study still has limitations such as the overestimation effects caused by the sample size and the risk of bias caused by interventions. Future research will attempt to overcome these limitations and comprehensively assess the effect of community nursing on the rehabilitation of stroke survivors.

Whole-genome sequencing of allotetraploid bermudagrass reveals the origin of Cynodon and candidate genes for salt tolerance.

Bermudagrass (Cynodon dactylon) is a globally distributed, extensively used warm-season turf and forage grass with high tolerance to salinity and drought stress in alkaline environments. However, the origin of the species and genetic mechanisms for salinity tolerance in the species are basically unknown. Accordingly, we set out to study evolution divergence events in the Cynodon genome and to identify genes for salinity tolerance. We developed a 604.0 Mb chromosome-level polyploid genome sequence for bermudagrass 'A12359' (n = 18). The C. dactylon genome comprises 2 complete sets of homoeologous chromosomes, each with approximately 30 000 genes, and most genes are conserved as syntenic pairs. Phylogenetic study showed that the initial Cynodon species diverged from Oropetium thomaeum approximately 19.7-25.4 million years ago (Mya), the A and B subgenomes of C. dactylon diverged approximately 6.3-9.1 Mya, and the bermudagrass polyploidization event occurred 1.5 Mya on the African continent. Moreover, we identified 82 candidate genes associated with seven agronomic traits using a genome-wide association study, and three single-nucleotide polymorphisms were strongly associated with three salt resistance genes: RAP2-2, CNG channels, and F14D7.1. These genes may be associated with enhanced bermudagrass salt tolerance. These bermudagrass genomic resources, when integrated, may provide fundamental insights into evolution of diploid and tetraploid genomes and enhance the efficacy of comparative genomics in studying salt tolerance in Cynodon.

H2O2 promotes trimming-induced tillering by regulating energy supply and redox status in bermudagrass.

Tillering/branching pattern plays a significant role in determining the structure and diversity of grass, and trimming has been found to induce tillering in turfgrass. Recently, it has been reported that hydrogen peroxide (H2O2) regulates axillary bud development. However, the role of H2O2 in trimming-induced tillering in bermudagrass, a kind of turfgrass, remains unclear. Our study unveils the significant impact of trimming on promoting the sprouting and growth of tiller buds in stolon nodes, along with an increase in the number of tillers in the main stem. This effect is accompanied by spatial-temporal changes in cytokinin and sucrose content, as well as relevant gene expression in axillary buds. In addition, the partial trimming of new-born tillers results in an increase in sucrose and starch reserves in their leaves, which can be attributed to the enhanced photosynthesis capacity. Importantly, trimming promotes a rapid H2O2 burst in the leaves of new-born tillers and axillary stolon buds. Furthermore, exogenous application of H2O2 significantly increases the number of tillers after trimming by affecting the expression of cytokinin-related genes, bolstering photosynthesis potential, energy reserves and antioxidant enzyme activity. Taken together, these results indicate that both endogenous production and exogenous addition of H2O2 enhance the inductive effects of trimming on the tillering process in bermudagrass, thus helping boost energy supply and maintain the redox state in newly formed tillers.

Continuous Versus Intermittent Control Cuff Pressure for Preventing Ventilator-Associated Pneumonia: An Updated Meta-Analysis.

OBJECTIVE: This study aimed to evaluate the effect of continuous control cuff pressure (CCCP) versus intermittent control cuff pressure (ICCP) for the prevention of ventilator-associated pneumonia (VAP) in critically ill patients. METHODS: Relevant literature was searched in several databases, including PubMed, Embase, Web of Science, ProQuest, the Cochrane Library, Wanfang Database and China National Knowledge Infrastructure between inception and September 2022. Randomized controlled trials were considered eligible if they compared CCCP with ICCP for the prevention of VAP in critically ill patients. This meta-analysis was performed using the RevMan 5.3 and Trial Sequential Analysis 0.9 software packages. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework was used to assess the level of evidence. RESULTS: We identified 14 randomized control trials with a total of 2080 patients. Meta-analysis revealed that CCCP was associated with a significantly lower incidence of VAP compared with ICCP (relative risk [RR] = 0.52; 95% confidence interval [CI]: 0.37-0.74; P < 0.001), although considerable heterogeneity was observed (I2 = 71%). Conducting trial sequential analysis confirmed the finding, and the GRADE level was moderate. Subgroup analysis demonstrated that CCCP combined with subglottic secretion drainage (SSD) had a more significant effect on reducing VAP (RR = 0.39; 95% CI = 0.29-0.52; P < 0.001). The effect of CCCP on ventilator-associated respiratory infection (VARI) incidence was uncertain (RR = 0.81; 95% CI = 0.53-1.24; P = 0.34; I2 = 61%). Additionally, CCCP significantly reduced the duration of mechanical ventilation (MV) (mean difference [MD] = -2.42 days; 95% CI = -4.71-0.12; P = 0.04; I2 = 87%). Descriptive analysis showed that CCCP improved the qualified rate of cuff pressure. However, no significant differences were found in the length of intensive care unit (ICU) stay (MD = 2.42 days; 95% CI = -1.84-6.68; P = 0.27) and ICU mortality (RR = 0.86; 95% CI = 0.74-1.00; P = 0.05). CONCLUSION: Our findings suggest that the combination of CCCP and SSD can reduce the incidence of VAP and the duration of MV and maintain the stability of cuff pressure. A combination of CCCP and SSD applications is suggested for preventing VAP.

Genome-wide identification, characterization, and expression analysis of m6A readers-YTH domain-containing genes in alfalfa.

Eukaryotic messenger RNAs (mRNAs) are often modified with methyl groups at the N6 position of adenosine (m6A), and these changes are interpreted by YTH domain-containing proteins to regulate the metabolism of m6A-modified mRNAs. Although alfalfa (Medicago sativa) is an established model organism for forage development, the understanding of YTH proteins in alfalfa is still limited. In the present investigation, 53 putative YTH genes, each encoding a YT521 domain-containing protein, were identified within the alfalfa genome. These genes were categorized into two subfamilies: YTHDF (49 members) and YTHDC (four members). Each subfamily demonstrates analogous motif distributions and domain architectures. Specifically, proteins encoded by MsYTHDF genes incorporate a single domain structure, while those corresponding to MsYTH5, 8, 12, 16 who are identified as members of the MsYTHDC subfamily, exhibit CCCH-type zinc finger repeats at their N-termini. It is also observed that the predicted aromatic cage pocket that binds the m6A residue of MsYTHDC consists of a sequence of two tryptophan residues and one tyrosine residue (WWY). Conversely, in MsYTHDF, the binding pocket comprises two highly conserved tryptophan residues and either one tryptophan residue (WWW) or tyrosine residue (WWY) in MsYTHDF.Through comparative analysis of qRT-PCR data, we observed distinct expression patterns in specific genes under abiotic stress, indicating their potential regulatory roles. Notably, five genes (MsYTH2, 14, 26, 27, 48) consistently exhibit upregulation, and two genes (MsYTH33, 35) are downregulated in response to both cold and salt stress. This suggests a common mechanism among these YTH proteins in response to various abiotic stressors in alfalfa. Further, integrating qRT-PCR with RNA-seq data revealed that MsYTH2, MsYTH14, and MsYTH16 are highly expressed in leaves at various development stages, underscoring their potential roles in regulating the growth of these plant parts. The obtained findings shed further light on the biological functions of MsYTH genes and may aid in the selection of suitable candidate genes for future genetic enhancement endeavors aimed at improving salt and cold tolerance in alfalfa.

Burden of stroke in China and the different SDI regions over the world.

Background: Stroke is a significant global health issue, ranking as the second leading cause of death and the third leading cause of death and disability combined. This study aimed to examine the changes and differences in stroke burden from 1990 to 2019 in China and various global socio-demographic index (SDI) regions. Methods: Data were obtained from the Global Burden of Diseases Study 2019, which included the incidence, prevalence, mortality, disability-adjusted life years (DALY), years of life with disability (YLD), and years of life lost (YLL) of stroke. The change trend of stroke burden was assessed based on age-standardised rates per 100 000 person-years and estimated annual percentage changes. The average annual rate of change in stroke burden was analysed using the average annual percentage change from 1990 to 2019. Pearson correlation analysis was used to explore the strength and direction of the correlation between stroke burden and SDI. Results: Regions with high SDI showed the largest decline in age-standardised incidence, death, DALY, YLD, and YLL rates of stroke from 1990 to 2019. China experienced the largest increase in age-standardised prevalence and YLD rates of stroke from 1990 to 2019. There were significant differences in the average annual percent change in stroke burden among the majority of SDI regions. The burden for stroke at the national level was inversely correlated with SDI, despite some exceptions (Incidence: R = -0.417, P < 0.001; prevalence: R = -0.297, P < 0.001; mortality: R = -0.510, P < 0.001; DALY: R = -0.550, P < 0.001; YLD: R = -0.125, P = 0.075; YLL: R = -0.569, P < 0.001). Conclusions: There were significant differences in the stroke burden across different regions with varying SDI levels from 1990 to 2019. The age-standardised prevalence rate and attributable disability burden of stroke remain substantial in different SDI regions, making it a major contributor to the overall disease burden. The severe burden of stroke highlights the importance of primary and secondary stroke-prevention strategies. Therefore, future strategies to prevent and reduce the burden of stroke should be formulated and implemented according to the SDI of each country.

Association of MMP3, MMP14, and MMP25 gene polymorphisms with cerebral stroke risk: a case-control study.

BACKGROUND: Cerebral stroke (CS) is the leading cause of death in China, and a complex disease caused by both alterable risk factors and genetic factors. This study intended to investigate the association of MMP3, MMP14, and MMP25 single nucleotide polymorphisms (SNPs) with CS risk in a Chinese Han population. METHODS: A total of 1,348 Han Chinese were recruited in this case-control study. Four candidate loci including rs520540 A/G and rs679620 T/C of MMP3, rs2236302 G/C of MMP14, and rs10431961 T/C of MMP25 were successfully screened. The correlation between the four SNPs and CS risk was assessed by logistic regression analysis. The results were analyzed by false-positive report probability (FPRP) for chance or significance. The interactions between four SNPs associated with CS risk were assessed by multifactor dimensionality reduction (MDR). RESULTS: rs520540 A/G and rs679620 C/T SNP in MMP3 were associated with risk of CS in allele, codominant, dominant and log-additive models. Ischemic stroke risk were significantly lower in carriers with rs520540-A allele and rs679620-T allele than those with G/G or C/C genotypes. However, rs520540-A allele and rs679620-T allele were associated with higher risk of hemorrhagic stroke. Stratified analysis showed that these two SNPs were associated with reduced risk of CS in aged < 55 years, non-smoking and non-drinking participants, and rs679620 SNP also reduced CS risk in male participants. The levels of uric acid, high-density lipoprotein cholesterol, and eosinophil were different among patients with different genotypes of rs520540 and rs679620. No statistically significant association was found between MMP14 rs2236302 G/C or MMP25 rs10431961 T/C with CS even after stratification by stroke subtypes, age, gender as well as smoking and drinking conditions in all the genetic models. CONCLUSION: MMP3 rs520540 A/G and rs679620 C/T polymorphisms were associated with CS risk in the Chinese Han population, which provides useful information for the prevention and diagnosis of CS.

The NR2B-targeted intervention alleviates the neuronal injuries at the sub-acute stage of cerebral ischemia: an exploration of stage-dependent strategy against ischemic insults.

Stroke is reported to be the second leading cause of death worldwide, among which ischemic stroke has fourfold greater incidence than intracerebral hemorrhage. Excitotoxicity induced by NMDAR plays a central role in ischemic stroke-induced neuronal death. However, intervention targeted NMDARs against ischemic stroke has failed, which may result from the complex composition of NMDARs and the dynamic changes of their subunits. In this current study, the levels of NR1, NR2A and NR2B subunits of NMDARs were observed upon different time points during the reperfusion after 1 h ischemia with the western blot assay. It was found that the changes of NR1 subunit were only detected after ischemia 1 h/reperfusion 1 day (1 d). While, the changes of NR2A and NR2B subunits may last to ischemia 1 h/reperfusion 7 day(7 d), indicating that NR2subunits may be a potential target for ischemia-reperfusion injuries at the sub-acute stage of ischemic stroke. Simultaneously, mitochondrial injuries in neurons were investigated with transmission electron microscopy (TEM), and mitochondrial dysfunction was evaluated with mitochondrial membrane proteins oxidative respiratory chain complex and OCR. When the antagonist of NMDARs was used before ischemic exposure, the neuronal mitochondrial dysfunction was alleviated, suggesting that these aberrant deviations of NMDARs from basal levels led to mitochondrial dysfunction. Furthermore, when the antagonist of NR2B was administrated intracerebroventricularly at the sub-acute cerebral ischemia, the volume of cerebral infarct region was decreased and the neural functions were improved. To sum up, the ratio of NR2B-containing NMDARs is vital for mitochondrial homeostasis and then neuronal survival. NR2B-targeted intervention should be chosen at the sub-acute stage of cerebral ischemia.

Transcriptomic analysis reveals that methyl jasmonate confers salt tolerance in alfalfa by regulating antioxidant activity and ion homeostasis.

Introduction: Alfalfa, a globally cultivated forage crop, faces significant challenges due to its vulnerability to salt stress. Jasmonates (JAs) play a pivotal role in modulating both plant growth and response to stressors. Methods: In this study, alfalfa plants were subjected to 150 mM NaCl with or without methyl jasmonate (MeJA). The physiological parameters were detected and a transcriptomic analysis was performed to elucidate the mechanisms underlying MeJA-mediated salt tolerance in alfalfa. Results: Results showed that exogenous MeJA regulated alfalfa seed germination and primary root growth in a dose-dependent manner, with 5µM MeJA exerting the most efficient in enhancing salt tolerance. MeJA at this concentration elavated the salt tolerance of young alfalfa seedlings by refining plant growth, enhancing antioxidant capacity and ameliorating Na+ overaccumulation. Subsequent transcriptomic analysis identified genes differentially regulated by MeJA+NaCl treatment and NaCl alone. PageMan analysis revealed several significantly enriched categories altered by MeJA+NaCl treatment, compared with NaCl treatment alone, including genes involved in secondary metabolism, glutathione-based redox regulation, cell cycle, transcription factors (TFs), and other signal transductions (such as calcium and ROS). Further weighted gene co-expression network analysis (WGCNA) uncovered that turquoise and yellow gene modules were tightly linked to antioxidant enzymes activity and ion content, respectively. Pyruvate decar-boxylase (PDC) and RNA demethylase (ALKBH10B) were identified as the most central hub genes in these two modules. Also, some TFs-hub genes were identified by WGCNA in these two modules highly positive-related to antioxidant enzymes activity and ion content. Discussion: MeJA triggered a large-scale transcriptomic remodeling, which might be mediated by transcriptional regulation through TFs or post-transcriptional regulation through demethylation. Our findings contributed new perspectives for understanding the underneath mechanisms by which JA-mediated salt tolerance in alfalfa.

Efficacy of Endotracheal Tube Cuff Modification in Preventing Ventilator-associated Pneumonia.

The aim of this study was to evaluate the effect of modifying the cuff on preventing ventilator-associated pneumonia (VAP). PubMed, Embase and Cochrane Library were systematically searched from inception to April 2022, for randomised controlled trials (RCTs) that compared the effect of a new type of cuff intubation with traditional cuff intubation on VAP incidence and intensive-care unit (ICU) mortality in mechanically ventilated patients. Nine RCTs with 1937 patients were finally evaluated. The pooled results for the incidence of VAP showed that the modified cuff significantly decreased the morbidity of VAP compared with the traditional cuff (relative ratio (RR) = 0.73, 95% confidence interval (CI) 0.56-0.95, p = 0.02). The subgroup analysis revealed that polyurethane (PU) cuff (RR = 0.82, 95% CI 0.46-1.48, p = 0.52), conical cuff (RR = 0.97, 95% CI 0.73-1.28, p = 0.82) and PU-conical cuff (RR = 1.36, 95% CI 0.85-2.18, p = 0.20) did not decrease the incidence of VAP. Moreover, the improved cuff combined with subglottic secretion drainage (SSD) could significantly reduce the VAP incidence (RR = 0.58, 95% CI 0.44-0.77, p = 0.0001). In terms of ICU mortality, there was no statistically significant difference (RR = 0.83, 95% CI 0.68-1.02, p = 0.08) between the two groups. The modified cuff is superior to the traditional cuff in VAP prevention. In particular, the modified cuff combined with subglottic secretion drainage has more advantages. Key Words: Ventilator-associated pneumonia, Intubation, Endotracheal cuff, Intensive care unit, Meta-analysis.

Root system architecture and genomic plasticity to salinity provide insights into salt-tolerant traits in tall fescue.

Salinity is detrimental to soil health, plant growth, and crop productivity. Understanding salt tolerance mechanisms offers the potential to introduce superior crops, especially in coastal regions. Root system architecture (RSA) plasticity is vital for plant salt stress adaptation. Tall fescue is a promising forage grass in saline regions with scarce RSA studies. Here, we used the computer-integrated and -automated programs EZ-Rhizo II and ROOT-Vis II to analyze and identify natural RSA variations and adaptability to high salt stress at physiological and genetic levels in 17 global tall fescue accessions. Total root length rather than the number of lateral roots contribute more to water uptake and could be used to separate salt-tolerant (LS-11) and -sensitive accessions (PI531230). Comparative evaluation of LS-11 and PI531230 demonstrated that the lateral root length rather than the main root contributed more towards the total root length in LS-11. Also, high water uptake was associated with a larger lateral root vector and position while low water intake was associated with an insignificant correlation between root length, vector, and position. To examine candidate gene expression, we performed transcriptome and transcription analyses using high-throughput RNA sequencing and real-time quantitative PCR, respectively of the lateral and main roots. The main root displayed more differentially expressed genes than the lateral root. A Poisson comparison of LS-11 vs PI531230 demonstrated significant upregulation of PLASMA MEMBRANE AQUAPORIN 1 and AUXIN RESPONSE FACTOR 22 in both the main and lateral root, which are associated with transmembrane water transport and the auxin-activated signaling system, respectively. There is also an upregulation of BASIC HELIX-LOOP-HELIX 5 in the main root and a downregulation in the lateral root, which is ascribed to sodium ion transmembrane transport, as well as an upregulation of THE MEDIATOR COMPLEX 1 assigned to water transport in the lateral root and a downregulation in the main root. Gene-protein interaction analysis found that more genes interacting with aquaporins proteins were upregulated in the lateral root than in the main root. We inferred that deeper main roots with longer lateral roots emanating from the bottom of the main root were ideal for tall fescue water uptake and salt tolerance, rather than many shallow roots, and that, while both main lateral roots may play similar roles in salt sensing and water uptake, there are intrinsic genomic differences.

CdWRKY2 transcription factor modulates salt oversensitivity in bermudagrass [Cynodon dactylon (L.) Pers.].

Common bermudagrass [Cynodon dactylon (L.) Pers.] has higher utilization potential on saline soil due to its high yield potential and excellent stress tolerance. However, key functional genes have not been well studied partly due to its hard transformation. Here, bermudagrass "Wrangler" successfully overexpressing CdWRKY2 exhibited significantly enhanced salt and ABA sensitivity with severe inhibition of shoot and root growth compared to the transgenic negative line. The reduced auxin accumulation and higher ABA sensitivity of the lateral roots (LR) under salt stress were observed in CdWRKY2 overexpression Arabidopsis lines. IAA application could rescue or partially rescue the salt hypersensitivity of root growth inhibition in CdWRKY2-overexpressing Arabidopsis and bermudagrass, respectively. Subsequent experiments in Arabidopsis indicated that CdWRKY2 could directly bind to the promoter region of AtWRKY46 and downregulated its expression to further upregulate the expression of ABA and auxin pathway-related genes. Moreover, CdWRKY2 overexpression in mapk3 background Arabidopsis could partly rescue the salt-inhibited LR growth caused by CdWRKY2 overexpression. These results indicated that CdWRKY2 could negatively regulate LR growth under salt stress via the regulation of ABA signaling and auxin homeostasis, which partly rely on AtMAPK3 function. CdWRKY2 and its homologue genes could also be useful targets for genetic engineering of salinity-tolerance plants.

Combined genomic and transcriptomic analysis reveals the contribution of tandem duplication genes to low-temperature adaptation in perennial ryegrass.

Perennial ryegrass (Lolium perenne L.) is an agronomically important cool-season grass species that is widely used as forage for ruminant animal production and cultivated in temperate regions for the establishment of lawns. However, the underlying genetic mechanism of the response of L. perenne to low temperature is still unclear. In the present study, we performed a comprehensive study and identified 3,770 tandem duplication genes (TDGs) in L. perenne, and evolutionary analysis revealed that L. perenne might have undergone a duplication event approximately 7.69 Mya. GO and KEGG pathway functional analyses revealed that these TDGs were mainly enriched in photosynthesis, hormone-mediated signaling pathways and responses to various stresses, suggesting that TDGs contribute to the environmental adaptability of L. perenne. In addition, the expression profile analysis revealed that the expression levels of TDGs were highly conserved and significantly lower than those of all genes in different tissues, while the frequency of differentially expressed genes (DEGs) from TDGs was much higher than that of DEGs from all genes in response to low-temperature stress. Finally, in-depth analysis of the important and expanded gene family indicated that the members of the ELIP subfamily could rapidly respond to low temperature and persistently maintain higher expression levels during all low temperature stress time points, suggesting that ELIPs most likely mediate low temperature responses and help to facilitate adaptation to low temperature in L. perenne. Our results provide evidence for the genetic underpinning of low-temperature adaptation and valuable resources for practical application and genetic improvement for stress resistance in L. perenne.

Involvement of cell cycle and ion transferring in the salt stress responses of alfalfa varieties at different development stages.

BACKGROUND: Alfalfa (Medicago sativa) is the worldwide major feed crop for livestock. However, forage quality and productivity are reduced by salt stress, which is a common issue in alfalfa-growing regions. The relative salt tolerance is changed during plant life cycle. This research aimed to investigate the relative salt tolerance and the underlying mechanisms of two alfalfa varieties at different developmental stages. RESULTS: Two alfalfa varieties, "Zhongmu No.1 (ZM1)" and "D4V", with varying salt tolerance, were subjected to salt stress (0, 100, 150 mM NaCl). When the germinated seeds were exposed to salt stress, D4V exhibited enhanced primary root growth compared to ZM1 due to the maintenance of meristem size, sustained or increased expression of cell cycle-related genes, greater activity of antioxidant enzymes and higher level of IAA. These findings indicated that D4V was more tolerant than ZM1 at early developmental stage. However, when young seedlings were exposed to salt stress, ZM1 displayed a lighter wilted phenotype and leaf cell death, higher biomass and nutritional quality, lower relative electrolytic leakage (EL) and malondialdehyde (MDA) concentration. In addition, ZM1 obtained a greater antioxidant capacity in leaves, indicated by less accumulation of hydrogen peroxide (H2O2) and higher activity of antioxidant enzymes. Further ionic tissue-distribution analysis identified that ZM1 accumulated less Na+ and more K+ in leaves and stems, resulting in lower Na+/K+ ratio, because of possessing higher expression of ion transporters and sensitivity of stomata closure. Therefore, the relative salt tolerance of ZM1 and D4V was reversed at young seedling stages, with the young seedlings of the former being more salt-tolerant. CONCLUSION: Our data revealed the changes of relative order of salt tolerance between alfalfa varieties as they develop. Meristem activity in primary root tips and ion transferring at young seedling stages were underlying mechanisms that resulted in differences in salt tolerance at different developmental stages.

Circular RNA ciRS-7 affects the propagation of Cryptosporidium parvum in HCT-8 cells via regulating miR-135a-5p/stat1 axis.

Cryptosporidium spp. are protozoan parasites that mainly inhabit intestinal epithelial cells, causing diarrheal diseases in humans and a great number of animals. Cryptosporidium parvum is the most common zoonotic species, responsible for nearly 45% of human cryptosporidiosis worldwide. Understanding the interaction mechanisms between C. parvum and host gastrointestinal epithelial cells has significant implications to control cryptosporidiosis. One up-regulated circRNA ciRS-7 was found previously by our group to promote in vitro propagation of C. parvum in HCT-8 cells. In the present study, miR-135a-5p, was found to be a miRNA target of ciRS-7. Cryptosporidium parvum infection induced significantly down-regulation of miR-135a-5p and dramatic up-regulation of its potential target stat1 gene at mRNA and protein levels. Dual luciferase reporter assays validated the physical interactions between miR-135a-5p and stat1, and between ciRS-7 and miR-135a-5p. Further study revealed that ciRS-7 could sponge miR-135a-5p to positively regulate the protein levels of STAT1 and phosphorylated STAT1 (p-STAT1) and thus promote C. parvum propagation in HCT-8 cells. Our findings further reveal the mystery of regulatory roles of host circRNAs during Cryptosporidium infection, and provide a novel insight to develop strategies to control cryptosporidiosis.

Salt-responsive bermudagrass microRNAs and insights into light reaction photosynthetic performance.

Introduction: Bermudagrass (Cynodon dactylon L.) is a warm-season grass with high drought and salt tolerance. However, its cultivation as a silage crop is limited by its lower forage value when compared to other C4 crops. Because of its high genetic variability in abiotic stress tolerance, bermudagrass-mediated genetic breeding offers significant promise for introducing alternative fodder crops in saline and drought-affected regions, and improved photosynthetic capacity is one way for increasing forage yield. Methods: Here, we used RNA sequencing to profile miRNAs in two bermudagrass genotypes with contrasting salt tolerance growing under saline conditions. Results: Putatively, 536 miRNA variants were salt-inducible, with the majority being downregulated in salt-tolerant vs sensitive varieties. Also, seven miRNAs putatively targeted 6 genes which were significantly annotated to light reaction photosynthesis. Among the microRNAs, highly abundant miRNA171f in the salt tolerant regime targeted Pentatricopeptide repeat-containing protein and dehydrogenase family 3 member F1 both annotated to electron transport and Light harvesting protein complex 1 genes annotated to light photosynthetic reaction in salt tolerant regime vs salt sensitive counterparts. To facilitate genetic breeding for photosynthetic capacity, we overexpressed miR171f in Medicago tracantula which resulted in a substantial increase in the chlorophyll transient curve, electron transport rate, quantum yield of photosystem II non photochemical quenching, NADPH and biomass accumulation under saline conditions while its targets were downregulated. At ambient light level the electron transport was negatively correlated with all parameters while the NADPH was positively associated higher dry matter in mutants. Discussion: These results demonstrate that miR171f improves photosynthetic performance and dry matter accumulation via transcriptional repression of genes in the electron transport pathway under saline conditions and thus a target for breeding.

Characterization of CpCaM, a protein potentially involved in the growth of Cryptosporidium parvum.

Cryptosporidium parvum is an important apicomplexan parasite causing severe diarrhea in both humans and animals. Calmodulin (CaM), a multifunctional and universal calcium-binding protein, contributes to the growth and development of apicomplexan parasites, but the role of CaM in C. parvum remains unknown. In this study, the CaM of C. parvum encoded by the cgd2_810 gene was expressed in Escherichia coli, and the biological functions of CpCaM were preliminarily investigated. The transcriptional level of the cgd2_810 gene peaked at 36 h post infection (pi), and the CpCaM protein was mainly located around the nucleus of the whole oocysts, in the middle of sporozoites and around the nucleus of merozoites. Anti-CpCaM antibody reduced the invasion of C. parvum sporozoites by 30.69%. The present study indicates that CpCaM is potentially involved in the growth of C. parvum. Results of the study expand our knowledge on the interaction between host and Cryptosporidium.

Status and Risk Factors in Patients Requiring Unplanned Intensive Care Unit Readmission Within 48 Hours: A Retrospective Propensity-Matched Study in China.

Aim: This study investigated the current status and related risk factors of 48-hour unplanned return to the intensive care unit (ICU) to reduce the return rate and improve the quality of critical care management. Methods: Data were collected from 2365 patients discharged from the comprehensive ICU. Multivariate and 1:1 propensity score matching analyses were performed. Results: Forty patients (1.69%) had unplanned readmission to the ICU within 48 hours after transfer. The primary reason for return was respiratory failure (16 patients, 40%). Furthermore, respiratory failure (odds ratio [OR] = 5.994, p = 0.02) and the number of organ failures (OR = 5.679, p = 0.006) were independent risk factors for unplanned ICU readmission. Receiver operating characteristic curves were drawn for the predictive value of the number of organ injuries during a patient's unplanned transfer to the ICU (area under the curve [AUC] = 0.744, sensitivity = 60%, specificity = 77.5%). Conclusion: The reason for patient transfer and the number of organ injuries during the process were independent risk factors for patients who were critically ill. The number of organs damaged had a predictive value on whether the patient would return to the ICU within 48 hours.