Modulation instability in nonlinear media with sine-oscillatory nonlocal response function and pure quartic diffraction.

Modulation instability of one-dimensional plane wave is demonstrated in nonlinear Kerr media with sine-oscillatory nonlocal response function and pure quartic diffraction. The growth rate of modulation instability, which depends on the degree of nonlocality, coefficient of quartic diffraction, type of the nonlinearity and the power of plane wave, is analytically obtained with linear-stability analysis. Different from other nonlocal response functions, the maximum of the growth rate in media with sine-oscillatory nonlocal response function occurs always at a particular wave number. Theoretical results of modulation instability are confirmed numerically with split-step Fourier transform. Modulation instability can be controlled flexibly by adjusting the degree of nonlocality and quartic diffraction.

Comparison of Copper-Tolerance Genes between Different Groups of Acidovorax citrulli.

Acidovorax citrulli populations exhibit genetic and phenotypic variations, particularly in terms of copper tolerance. Group I strains of A. citrulli generally exhibit higher copper tolerance compared to group II strains. This study aims to identify genes involved in copper tolerance to better understand the differences in copper tolerance between group I and group II strains. Representative strains pslb65 (group I) and pslbtw14 (group II) were selected for comparison. Deletion mutants of putative copper-tolerance genes and their corresponding complementary strains were constructed. The copper tolerance of each strain was evaluated using the minimum inhibitory concentration method. The results showed that the copA, copZ, cueR, and cueO genes played major roles in copper tolerance in A. citrulli, while cusC-like, cusA-like, and cusB-like genes had minor effects. The different expression levels of copper-tolerance-related genes in pslb65 and pslbtw14 under copper stress indicated that they had different mechanisms for coping with copper stress. Overall, this study provides insights into the mechanisms of copper tolerance in A. citrulli and highlights the importance of specific genes in copper tolerance.

Pheochromocytoma-induced myocardial infarction: A case report.

The pheochromocytoma is an uncommon endocrine neoplasm that originates from chromaffin cells and causes significant cardiovascular effects through the intermittent or sustained release of catecholamines. In this report, we present a rare case of myocardial infarction (MI) induced by pheochromocytoma. A 53-year-old female presented to the emergency department with a history of intermittent palpitations, back pain, and sweating for over 10 years, which had worsened over the past 2 days. The patient's cardiac enzymes and troponin levels were significantly elevated, and the electrocardiogram (ECG) showed ST-segment elevation, leading to an initial diagnosis of acute myocardial infarction. Echocardiography revealed apical ballooning, indicative of stress cardiomyopathy. Emergency coronary angiography revealed no significant stenosis, and the patient's blood pressure was fluctuating. Computerized tomography (CT) scan of the adrenal gland revealed a bilateral adrenal mass, with the left adrenal mass being larger in size after contrast-enhanced CT scan. The patient's left adrenal gland was successfully removed through laparoscopic adrenalectomy, and histopathology results confirmed the presence of adrenal pheochromocytoma. Follow-up for 3 months after discharge showed the patient had no symptoms and good prognosis. The abnormal findings on echocardiography and ECG resolved. Prompt diagnosis and management of pheochromocytoma are crucial for a favorable prognosis.

Paenibacillus glufosinatiresistens sp. nov., a glufosinate-resistant bacterium isolated from sludge.

A Gram-stain-positive bacterium capable of resisting 5.0 mM glufosinate, designated strain YX-27T, was isolated from a sludge sample collected from a factory in Wuxi, Jiangsu, PR China. Cells were rod-shaped, facultatively anaerobic, endospore-forming, and motile by peritrichous flagella. Growth was observed at 15-42 °C (optimum at 30 °C), pH 4.0-8.0 (optimum pH 7.0-7.5) and with 0-2.5% NaCl (w/v; optimum, 0.5 %). Strain YX-27T could tolerate up to 6.0 mM glufosinate. Strain YX-27T showed the highest 16S rRNA gene sequence similarity to Paenibacillus tianjinensis TB2019T (96.17 %), followed by Paenibacillus odorifer DSM 1539T (96.15 %), Paenibacillus sophorae S27T (96.04 %), Paenibacillus apii 7124T (96.02 %) and Paenibacillus stellifer DSM 14472T (95.87 %). The phylogenetic tree based on genome and 16S rRNA gene sequences indicated that strain YX-27T was clustered in the genus Paenibacillus but formed a separate clade. The genome size of YX-27T was 5.22 Mb with a G+C content of 57.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between the genomes of strain YX-27T and 12 closely related type strains ranged from 70.8 to 74.8% and 19.8 to 23.0 %, respectively. The major cellular fatty acids were C16 : 0, anteiso-C15 : 0 and iso-C16 : 0. The major polar lipids were one diphosphatidylglycerol, one phosphatidylethanolamine, one phosphatidylglycerol, one phospholipid, four aminophospholipids and four unidentified lipids. The predominant respiratory quinone was MK-7. Based on phylogenetic, genomic, chemotaxonomic and phenotypic data, strain YX-27T was considered to represent a novel species for which the name Paenibacillus glufosinatiresistens sp. nov. is proposed, with YX-27T (=MCCC 1K08803T= KCTC 43611T) as the type strain.

Translatome and Transcriptome Analyses Reveal the Mechanism that Underlies the Enhancement of Salt Stress by the Small Peptide Ospep5 in Plants.

Salt stress significantly impedes plant growth and the crop yield. This study utilized de novo transcriptome assembly and ribosome profiling to explore mRNA translation's role in rice salt tolerance. We identified unrecognized translated open reading frames (ORFs), including 42 upstream transcripts and 86 unannotated transcripts. A noteworthy discovery was the role of a small ORF, Ospep5, in conferring salt tolerance. Overexpression of Ospep5 in plants increased salt tolerance, while its absence led to heightened sensitivity. This hypothesis was corroborated by the findings that exogenous application of the synthetic small peptide Ospep5 bolstered salt tolerance in both rice and Arabidopsis. We found that the mechanism underpinning the Ospep5-mediated salt tolerance involves the maintenance of intracellular Na+/K+ homeostasis, facilitated by upregulation of high-affinity potassium transporters (HKT) and Na+/H+ exchangers (SOS1). Furthermore, a comprehensive multiomics approach, particularly ribosome profiling, is instrumental in uncovering unannotated ORFs and elucidating their functions in plant stress responses.

An integrative analysis reveals the prognostic value and potential functions of MTMR2 in hepatocellular carcinoma.

Abnormal expression of myotubularin-related protein 2 (MTMR2) has been identified in certain types of cancer, leading to varying effects on tumor genesis and progression. However, the various biological significances of MTMR2 in hepatocellular carcinoma (HCC) have not been systematically and comprehensively studied. The aim of this study was to explore the role of MTMR2 in HCC. We obtained the raw data from Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Afterward, we analyzed the data using R and cBioPortal. We investigated the connection between MTMR2 and its expression, prognosis, clinical significance, methylation, genetic alterations, tumor microenvironment (TME), tumor mutation burden (TMB), and drug reactivity in HCC patients. MTMR2 expression levels in HCC cells were validated through western blotting and RT-qPCR. MTMR2 exhibits high levels of expression across a wide range of cancer types, including HCC. MTMR2 is diagnostically valuable in detecting HCC, with its up-regulated expression often being indicative of poor prognosis among HCC patients. The in vitro experiments confirmed elevated MTMR2 expression in HepG2, HUH-7, and MHCC-97H cells. Univariate and multivariate Cox analysis demonstrated that MTMR2 was an independent prognostic factor in HCC patients. The cg20195272 site has the highest degree of methylation in MTMR2, and it is positively correlated with MTMR2 expression. Patients with high levels of methylation at the cg20195272 site show poor prognosis. Analysis of the TME indicates that high expression of MTMR2 is associated with elevated ESTIMATE score and that MTMR2 expression correlates positively with infiltration by resting memory CD4 T cells, activated dendritic cells, as well as several immune checkpoints. There is a negative correlation between MTMR2 expression and TMB, and drug sensitivity analyses have shown that higher MTMR2 expression is associated with lower IC50 values. This study indicates that increased expression of MTMR2 may play a crucial role in the occurrence, progression, diagnosis, prognostic prediction and drug therapy of HCC.

Acidovorax citrulli type III effector AopU interferes with plant immune responses and interacts with a watermelon E3 ubiquitin ligase.

Acidovorax citrulli is a seed-borne bacterium that causes bacterial fruit blotch of watermelon and other cucurbit plants worldwide. It uses a type III secretion system to inject type III effectors (T3Es) into plant cells, which affect the host immune responses and facilitate pathogen colonization. However, the current understanding of the specific molecular mechanisms and targets of these effectors in A. citrulli is limited. In this study, we characterized a novel T3E called AopU in A. citrulli group II strain Aac5, which shares homology with XopU in Xanthomonas oryzae. The Agrobacterium-mediated gene transient expression system was used to study the effect of AopU on host immunity. The results showed that AopU localized on the cell membrane and nucleus of Nicotiana benthamiana, inhibited reactive oxygen species burst induced by flg22 and the expression of marker genes associated with pathogen-associated molecular pattern-triggered immunity, but activated salicylic acid and jasmonic acid signal pathways. Further investigations revealed that AopU interacts with E3 ubiquitin ligase ClE3R in watermelon, both in vitro and in vivo. Interestingly, the deletion of aopU did not affect the virulence of A. citrulli, suggesting that AopU may have functional redundancy with other effectors in terms of its role in virulence. Collectively, these findings provide new insights into the mechanism of plant immune responses regulated by A. citrulli T3Es.

Targeted Knockdown of Genes in the Choroid Plexus.

The choroid plexus (ChP) serves as a critical gateway for immune cell infiltration into the central nervous system (CNS) under both physiological and pathological conditions. Recent research has shown that regulating ChP activity may offer protection against CNS disorders. However, studying the biological function of the ChP without affecting other brain regions is challenging due to its delicate structure. This study presents a novel method for gene knockdown in ChP tissue using adeno-associated viruses (AAVs) or cyclization recombination enzyme (Cre) recombinase protein consisting of TAT sequence (CRE-TAT). The results demonstrate that after injecting AAV or CRE-TAT into the lateral ventricle, the fluorescence was exclusively concentrated in the ChP. Using this approach, the study successfully knocked down the adenosine A2A receptor (A2AR) in the ChP using RNA interference (RNAi) or Cre/locus of X-overP1 (Cre/LoxP) systems, and showed that this knockdown could alleviate the pathology of experimental autoimmune encephalomyelitis (EAE). This technique may have important implications for future research on the ChP's role in CNS disorders.

pilA Gene Contributes to Virulence, Motility, Biofilm Formation, and Interspecific Competition of Bacteria in Acidovorax citrulli.

Acidovorax citrulli, the causative agent of bacterial fruit blotch, can be divided into two main groups based on factors such as pathogenicity and host species preference. PilA is an important structural and functional component of type IV pili (T4P). Previous studies have found significant differences in pilA DNA sequences between group I and group II strains of A. citrulli. In this study, we characterized pilA in the group I strain pslb65 and the group II strain Aac5. pilA mutants, complementation strains, and cross-complementation strains were generated, and their biological phenotypes were analyzed to identify functional differences between pilA in the two groups. pilA deletion mutants (pslb65-ΔpilA and Aac5-ΔpilA) showed significantly reduced pathogenicity compared with the wild-type (WT) strains; pslb65-ΔpilA also completely lost twitching motility, whereas Aac5-ΔpilA only partially lost motility. In King's B medium, there were no significant differences in biofilm formation between pslb65-ΔpilA and WT pslb65, but Aac5-ΔpilA showed significantly reduced biofilm formation compared to WT Aac5. In M9 minimal medium, both mutants showed significantly lower biofilm formation compared to the corresponding WT strains, although biofilm formation was recovered in the complementation strains. The biofilm formation capacity was somewhat recovered in the cross-complementation strains but remained significantly lower than in the WT strains. The interspecies competitive abilities of pslb65-ΔpilA and Aac5-ΔpilA were significantly lower than in the WT strains; Aac5-ΔpilA was more strongly competitive than pslb65-ΔpilA, and the complementation strains recovered competitiveness to WT levels. Furthermore, the cross-complementation strains showed stronger competitive abilities than the corresponding WT strains. The relative expression levels of genes related to T4P and the type VI secretion system were then assessed in the pilA mutants via quantitative PCR. The results showed significant differences in the relative expression levels of multiple genes in pslb65-ΔpilA and Aac5-ΔpilA compared to the corresponding WT stains. This indicated the presence of specific differences in pilA function between the two A. citrulli groups, but the regulatory mechanisms involved require further study.

Complete Genome Sequence of Erwinia amylovora Strain 99east-3-1, Isolated from Pyrus sinkiangensis in China.

Here, we report the complete genome sequence of Erwinia amylovora strain 99east-3-1, which was isolated from Pyrus sinkiangensis in Xinjiang Uygur Autonomous Region, China.

Blocking the IFN-gamma signal in the choroid plexus confers resistance to experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory infiltration and demyelination in the central nervous system (CNS). IFN-gamma (IFN-γ), a critically important immunomodulator, has been widely studied in MS pathology. The confusing and complex effects of IFN-γ in MS patients and rodent models, however, cause us to look more closely at its exact role in MS. In this study, we identified the role of the IFN-γ signaling in the choroid plexus (CP) in the experimental autoimmune encephalomyelitis (EAE) model. We found that the IFN-γ signal was rapidly amplified when CNS immune cell infiltration occurred in the CP during the progressive stage. Furthermore, using two CP-specific knockdown strategies, we demonstrated that blocking the IFN-γ signal via knockdown of IFN-γR1 in the CP could protect mice against EAE pathology, as evidenced by improvements in clinical scores and infiltration. Notably, knocking down IFN-γR1 in the CP reduced the local expression of adhesion molecules and chemokines. This finding suggests that IFN-γ signaling in the CP may participate in the pathological process of EAE by preventing pathological T helper (Th) 17+ cells from infiltrating into the CNS. Finally, we showed that the unbalanced state of IFN-γ signaling between peripheral lymphocytes and the choroid plexus may determine whether IFN-γ has a protective or aggravating effect on EAE pathology. Above all, we discovered that IFN-γR1-mediated IFN-γ signaling in the CP was a vital pathway in the pathological process of EAE.

ntrC Contributes to Nitrogen Utilization, Stress Tolerance, and Virulence in Acidovorax citrulli.

Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, severely damages watermelon, melon, and other cucurbit crops worldwide. Nitrogen, one of the most important limiting elements in the environment, is necessary for the growth and reproduction of bacteria. As a nitrogen-regulating gene, ntrC plays an important role in maintaining bacterial nitrogen utilization and biological nitrogen fixation. However, the role of ntrC has not been determined for A. citrulli. In this study, we constructed a ntrC deletion mutant and a corresponding complementary strain in the background of the A. citrulli wild-type strain, Aac5. Through phenotype assays and qRT-PCR analysis, we investigated the role of ntrC in A. citrulli in nitrogen utilization, stress tolerance, and virulence against watermelon seedlings. Our results showed that the A. citrulli Aac5 ntrC deletion mutant lost the ability to utilize nitrate. The ntrC mutant strain also exhibited significantly decreased virulence, in vitro growth, in vivo colonization ability, swimming motility, and twitching motility. In contrast, it displayed significantly enhanced biofilm formation and tolerance to stress induced by oxygen, high salt, and copper ions. The qRT-PCR results showed that the nitrate utilization gene nasS; the Type III secretion system-related genes hrpE, hrpX, and hrcJ; and the pili-related gene pilA were significantly downregulated in the ntrC deletion mutant. The nitrate utilization gene nasT, and the flagellum-related genes flhD, flhC, fliA, and fliC were significantly upregulated in the ntrC deletion mutant. The expression levels of ntrC gene in the MMX-q and XVM2 media were significantly higher than in the KB medium. These results suggest that the ntrC gene plays a pivotal role in the nitrogen utilization, stress tolerance, and virulence of A. citrulli.

Quantitative evaluation of hemodynamic parameters by echocardiography in patients with post-cardiotomy cardiac shock supported by extracorporeal membrane oxygenation.

BACKGROUND: When drugs fail to reverse post-cardiotomy cardiac shock (PCS), extracorporeal membrane oxygenation (ECMO) is considered the most effective adjuvant strategy. Transthoracic echocardiography is a useful imaging modality for monitoring of cardiac hemodynamics. The aim of this study was to investigate the value of echocardiography for monitoring the left and right heart hemodynamics in PCS patients before, during, and after weaning from ECMO. METHODS: Fifty-two patients were divided into successful weaning group (group A, n = 23) and non-successful weaning group (group B, n = 29). Hemodynamic parameters measured by echocardiography were collected before, during, and after ECMO. The intra-group changes and inter-group differences were retrospectively analyzed. RESULTS: In group A, the central venous pressure (CVP), proximal right ventricular outflow tract (RVOT), tricuspid annular plane systolic excursion (TAPSE), velocity of tricuspid valve (TVDV), and systolic velocity of tricuspid annulus ([Formula: see text]) during ECMO were significantly lower than those before ECMO. After ECMO, left ventricular ejection fraction (LVEF), systolic velocity of mitral annulus ([Formula: see text]), and velocity-time integral of LV outflow tract (LVOT-VTI) were higher than pre-ECMO levels, and CVP, LVEF, [Formula: see text], LVOT-VTI, RVOT, TAPSE, TVDV and [Formula: see text] were higher than those during ECMO (all P < 0.05). In group B, compared to pre-ECMO, subjects exhibited decreased CVP, RVOT, TAPSE, TVDV and [Formula: see text] during ECMO. TAPSE, TVDV, and [Formula: see text] were continuously lower after ECMO, while CVP and RVOT increased after ECMO (all P < 0.05). After ECMO, LVEF, [Formula: see text], LVOT-VTI, TAPSE, TVDV and [Formula: see text] in group A were higher than those in group B (all P < 0.05). Inter-group comparison showed the LVEF and RV Tei indices of group A were significantly different than those of group B before, during, and after ECMO. CONCLUSION: Quantitative assessment of both LV and RV by echocardiography is important for ECMO weaning. Patients with better LVEF and lower RV Tei index may have a better chance of successful weaning from ECMO.

Identification of the Causal Agent of Bacterial Leaf Spot on Watermelon in China.

Watermelon diseases caused by pathogenic bacteria were endemic in Liaoning and Jilin Provinces from 2019 to 2020 in China, resulting in serious economic losses to the watermelon industry. This study characterized 56 strains isolated from symptomatic watermelon leaves collected from Liaoning and Jilin Provinces. Through morphological observation, 16S rRNA and gyrB sequence analysis, and BIOLOG profiles, the pathogen was identified as Pseudomonas syringae. In China, the watermelon disease caused by P. syringae was reported for the first time. The multilocus sequence analysis showed that the isolated strains belonged to three different clades within P. syringae phylogroup 2. Interestingly, most of them (79%) belonged to clade 2a, 14% were clade 2b, and 7% were clade 2d. This indicates that bacterial leaf spot outbreaks of watermelon in China were caused by multiple sources and mainly by P. syringae clade 2a.

Adenosine A2A receptor controls the gateway of the choroid plexus.

The choroid plexus (CP) is one of the key gateways regulating the entry of peripheral immune cells into the CNS. However, the neuromodulatory mechanisms of maintaining its gateway activity are not fully understood. Here, we identified adenosine A2A receptor (A2AR) activity as a regulatory signal for the activity of CP gateway under physiological conditions. In association with a tightly closed CP gateway, we found that A2AR was present at low density in the CP. The RNA-seq analysis revealed that the A2AR antagonist KW6002 affected the expression of the cell adhesion molecules' (CAMs) pathway and cell response to IFN-γ in the CP. Furthermore, blocking or activating A2AR signaling in the CP resulted in a decreased and an increased, respectively, expression of lymphocyte trafficking determinants and disruption of the tight junctions (TJs). Furthermore, A2AR signaling regulates the CP permeability. Thus, A2AR activity in the CP may serve as a therapeutic target for remodeling the immune homeostasis in the CNS with implications for the treatment of neuroimmunological disorders.

Engineered nanodrug targeting oxidative stress for treatment of acute kidney injury.

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid decline in renal function, and is associated with a high risk of death. Many pathological changes happen in the process of AKI, including crucial alterations to oxidative stress levels. Numerous efforts have thus been made to develop effective medicines to scavenge excess reactive oxygen species (ROS). However, researchers have encountered several significant challenges, including unspecific biodistribution, high biotoxicity, and in vivo instability. To address these problems, engineered nanoparticles have been developed to target oxidative stress and treat AKI. This review thoroughly discusses the methods that empower nanodrugs to specifically target the glomerular filtration barrier and presents the latest achievements in engineering novel ROS-scavenging nanodrugs in clustered sections. The analysis of each study's breakthroughs and imperfections visualizes the progress made in developing effective nanodrugs with specific biodistribution and oxidative stress-targeting capabilities. This review fills the blank of a comprehensive outline over current progress in applying nanotechnology to treat AKI, providing potential insights for further research.

A putative multi-sensor hybrid histidine kinase, BarA Ac , inhibits the expression of the type III secretion system regulator HrpG in Acidovorax citrulli.

Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, severely damages watermelon, melon, and other cucurbit crops worldwide. Although many virulence determinants have been identified in A. citrulli, including swimming motility, twitching motility, biofilm formation, and the type III secretion system (T3SS), research on their regulation is lacking. To study virulence regulation mechanisms, we found a putative histidine kinase BarA Ac that may be related to the T3SS regulator HrpG in A. citrulli. We deleted and characterized barAAc (Aave_2063) in A. citrulli Aac5 strain. Compared to the wild-type Aac5, virulence and early proliferation of barAAc mutant in host watermelon cotyledons were significantly increased, and induction of hypersensitive response in non-host tobacco was accelerated, while biofilm formation and swimming motility were significantly reduced. In addition, the transcriptomic analysis revealed that the expression of many T3SS-related genes was upregulated in the ΔbarAAc deletion mutant when cultured in KB medium. Meanwhile, the ΔbarAAc deletion mutant showed increased accumulation of the T3SS regulator HrpG in KB medium, which may account for the increased deployment of T3SS. This suggests that the putative histidine kinase BarA Ac is able to repress the T3SS expression by inhibiting HrpG in the KB medium, which appears to be important for rational energy allocation. In summary, our research provides further understanding of the regulatory network of A. citrulli virulence.

Acidovorax citrulli Effector AopV Suppresses Plant Immunity and Interacts with Aromatic Dehydratase ADT6 in Watermelon.

Bacterial fruit blotch (BFB) is a disease of cucurbit plants caused by Acidovorax citrulli. Although A. citrulli has great destructive potential, the molecular mechanisms of pathogenicity of A. citrulli are not clear, particularly with regard to its type III secreted effectors. In this study, we characterized the type III secreted effector protein, AopV, from A. citrulli strain Aac5. We show that AopV significantly inhibits reactive oxygen species and the expression of PTI marker genes, and helps the growth of Pseudomonas syringae D36E in Nicotiana benthamiana. In addition, we found that the aromatic dehydratase ADT6 from watermelon was a target of AopV. AopV interacts with ADT6 in vivo and in vitro. Subcellular localization indicated ADT6 and AopV were co-located at the cell membrane. Together, our results reveal that AopV suppresses plant immunity and targets ADT6 in the cell membrane. These findings provide an new characterization of the molecular interaction of A. citrulli effector protein AopV with host cells.

Hcp of the Type VI Secretion System (T6SS) in Acidovorax citrulli Group II Strain Aac5 Has a Dual Role as a Core Structural Protein and an Effector Protein in Colonization, Growth Ability, Competition, Biofilm Formation, and Ferric Iron Absorption.

A type VI secretion system (T6SS) gene cluster has been reported in Acidovorax citrulli. Research on the activation conditions, functions, and the interactions between key elements in A. citrulli T6SS is lacking. Hcp (Hemolysin co-regulated protein) is both a structural protein and a secretion protein of T6SS, which makes it a special element. The aims of this study were to determine the role of Hcp and its activated conditions to reveal the functions of T6SS. In virulence and colonization assays of hcp deletion mutant strain Δhcp, tssm (type VI secretion system membrane subunit) deletion mutant strain Δtssm and double mutant ΔhcpΔtssm, population growth was affected but not virulence after injection of cotyledons and seed-to-seedling transmission on watermelon. The population growth of Δhcp and Δtssm were lower than A. citrulli wild type strain Aac5 of A. citrulli group II at early stage but higher at a later stage. Deletion of hcp also affected growth ability in different culture media, and the decline stage of Δhcp was delayed in KB medium. Biofilm formation ability of Δhcp, Δtssm and ΔhcpΔtssm was lower than Aac5 with competition by prey bacteria but higher in KB and M9-Fe3+ medium. Deletion of hcp reduced the competition and survival ability of Aac5. Based on the results of Western blotting and qRT-PCR analyses, Hcp is activated by cell density, competition, ferric irons, and the host plant. The expression levels of genes related to bacterial secretion systems, protein export, and several other pathways, were significantly changed in the Δhcp mutant compared to Aac5 when T6SS was activated at high cell density. Based on transcriptome data, we found that a few candidate effectors need further identification. The phenotypes, activated conditions and transcriptome data all supported the conclusion that although there is only one T6SS gene cluster present in the A. citrulli group II strain Aac5, it related to multiple biological processes, including colonization, growth ability, competition and biofilm formation.

Green spaces, especially nearby forest, may reduce the SARS-CoV-2 infection rate: A nationwide study in the United States.

The coronavirus pandemic is an ongoing global crisis that has profoundly harmed public health. Although studies found exposure to green spaces can provide multiple health benefits, the relationship between exposure to green spaces and the SARS-CoV-2 infection rate is unclear. This is a critical knowledge gap for research and practice. In this study, we examined the relationship between total green space, seven types of green space, and a year of SARS-CoV-2 infection data across 3,108 counties in the contiguous United States, after controlling for spatial autocorrelation and multiple types of covariates. First, we examined the association between total green space and SARS-CoV-2 infection rate. Next, we examined the association between different types of green space and SARS-CoV-2 infection rate. Then, we examined forest-infection rate association across five time periods and five urbanicity levels. Lastly, we examined the association between infection rate and population-weighted exposure to forest at varying buffer distances (100 m to 4 km). We found that total green space was negative associated with the SARS-CoV-2 infection rate. Furthermore, two forest variables (forest outside park and forest inside park) had the strongest negative association with the infection rate, while open space variables had mixed associations with the infection rate. Forest outside park was more effective than forest inside park. The optimal buffer distances associated with lowest infection rate are within 1,200 m for forest outside park and within 600 m for forest inside park. Altogether, the findings suggest that green spaces, especially nearby forest, may significantly mitigate risk of SARS-CoV-2 infection.