The Effect of Two Siderophore-Producing Bacillus Strains on the Growth Promotion of Perennial Ryegrass under Cadmium Stress.

Cadmium (Cd) is a highly toxic and cumulative environmental pollutant. Siderophores are heavy metal chelators with high affinity to heavy metals, such as Cd. Ryegrass (Lolium perenne L.) has a potential remediation capacity for soils contaminated by heavy metals. Consequently, using ryegrass alongside beneficial soil microorganisms that produce siderophores may be an effective means to remediate soils contaminated with Cd. In this study, the Bacillus strains WL1210 and CD303, which were previously isolated from the rhizospheres of Nitraria tangutorum in Wulan and Peganum harmala L. in Dachaidan, Qinghai, China, respectively, both arid and sandy environments, were evaluated for heavy metal pollution mitigation. Our quantitative analyses have discerned that the two bacterial strains possess commendable attributes of phosphorus (P) solubilization and potassium (K) dissolution, coupled with the capacity to produce phytohormones. To assess the heavy metal stress resilience of these strains, they were subjected to a cadmium concentration gradient, revealing their incremental growth despite cadmium presence, indicative of a pronounced tolerance threshold. The subsequent phylogenetic analysis, bolstered by robust genomic data from conserved housekeeping genes, including 16S rDNA, gyr B gene sequencing, as well as dnaK and recA, delineated a species-level phylogenetic tree, thereby confirming the strains as Bacillus atrophaeus. Additionally, we identified the types of iron-carrier-producing strains as catechol (WL1210) and carboxylic acid ferrophilin (CD303). A genomic analysis uncovered functional genes in strain CD303 associated with plant growth and iron carrier biosynthesis, such as fnr and iscA. Ryegrass seed germination assays, alongside morphological and physiological evaluations under diverse heavy metal stress, underscored the strains' potential to enhance ryegrass growth under high cadmium stress when treated with bacterial suspensions. This insight probes the strains' utility in leveraging alpine microbial resources and promoting ryegrass proliferation.

Proline Metabolism in Response to Climate Extremes in Hairgrass.

Hairgrass (Deschampsia caespitosa), a widely distributed grass species considered promising in the ecological restoration of degraded grassland in the Qinghai-Xizang Plateau, is likely to be subjected to frequent drought and waterlogging stress due to ongoing climate change, further aggravating the degradation of grassland in this region. However, whether it would acclimate to water stresses resulting from extreme climates remains unknown. Proline accumulation is a crucial metabolic response of plants to challenging environmental conditions. This study aims to investigate the changes in proline accumulation and key enzymes in hairgrass shoot and root tissues in response to distinct climate extremes including moderate drought, moderate waterlogging, and dry-wet variations over 28 days using a completely randomized block design. The proline accumulation, contribution of the glutamate and ornithine pathways, and key enzyme activities related to proline metabolism in shoot and root tissues were examined. The results showed that water stress led to proline accumulation in both shoot and root tissues of hairgrass, highlighting the importance of this osmoprotectant in mitigating the effects of environmental challenges. The differential accumulation of proline in shoots compared to roots suggests a strategic allocation of resources by the plant to cope with osmotic stress. Enzymatic activities related to proline metabolism, such as Δ1-pyrroline-5-carboxylate synthetase, ornithine aminotransferase, Δ1-pyrroline-5-carboxylate reductase, Δ1-pyrroline-5-carboxylate dehydrogenase, and proline dehydrogenase, further emphasize the dynamic regulation of proline levels in hairgrass under water stress conditions. These findings support the potential for enhancing the stress resistance of hairgrass through the genetic manipulation of proline biosynthesis and catabolism pathways.

Drought stress tolerance and metabolomics of Medicago sativa induced by Bacillus amyloliquefaciens DGL1.

Introduction: This study used Bacillus amyloliquefaciens DGL1 isolated from the arid sandy land of the Qinghai-Tibetan Plateau as the research strain and investigated the effects of DGL1 on the biomass, physiology, and metabolites of Medicago sativa under different intensities of drought stress to provide a high-quality bacterial source and a theoretical basis for the research and development of biological fertilizer suitable for arid areas. Methods: The exopolysaccharides (EPS), 1-Aminocyclopropane-1-carboxylate deaminase (ACC), and phosphorus solubilizing capacity of DGL1 were determined. The effects of a DGL1 suspension on alfalfa biomass, physiological indexes, degree of peroxidation of cell membranes, and activity of antioxidant enzymes were determined after irrigating roots under drought stress. The effects on soil physicochemical properties were also evaluated, and metabolomics analysis was performed to explore the effect of DGL1 on the metabolites of alfalfa under drought stress. Results: Strain DGL1 produced extracellular polysaccharide EPS and ACC deaminase and was capable of phosphorus solubilization. Treatment with DGL1 increased the biomass of alfalfa under different degrees of drought stress, significantly increased the activities of alfalfa antioxidant enzymes Super Oxide Dismutase (SOD), Peroxidase (POD), and catalase (CAT), reduced the content of MDA and H2O2, and increased the content of quick-acting phosphorus, quick-acting potassium, ammonium nitrogen, and nitrate nitrogen in the soil, thus improving soil fertility. Through metabolomics analysis, DGL1 was shown to affect amino acid metabolic pathways, such as arginine, leucine, glutamate, and tyrosine, as well as the levels of energy-providing polysaccharides and lipids, in alfalfa under 15% PEG-6000 drought stress, enhancing alfalfa's capacity to resist drought stress. Discussion: Strain DGL1 enhances the drought suitability of alfalfa and has the potential for dryland development as a biological agent.

Genome-Wide Analyses of SlFWL Family Genes and Their Expression Profiles under Cold, Heat, Salt and Drought Stress in Tomato.

PLAC8 is a cysteine-rich protein that serves as a central mediator of tumor evolution in mammals. PLAC8 motif-containing proteins widely distribute in fungi, algae, higher plants and animals that have been described to be implicated in fruit size, cell number and the transport of heavy metals such as cadmium or zinc. In tomatoes, FW2.2 is a PLAC8 motif-containing gene that negatively controls fruit size by regulating cell division and expansion in the carpel ovary during fruit development. However, despite FW2.2, other FWL (FW2.2-Like) genes in tomatoes have not been investigated. In this study, we identified the 21 SlFWL genes, including FW2.2, examined their expression profiles under various abiotic adversity-related conditions. The SlFWL gene structures and motif compositions are conserved, indicating that tomato SlFWL genes may have similar roles. Cis-acting element analysis revealed that the SlFWL genes may participate in light and abiotic stress responses, and they also interacted with a variety of phytohormone-responsive proteins and plant development elements. Phylogenetic analyses were performed on five additional plant species, including Arabidopsis, pepper, soybean, rice and maize, these genes were classified into five subfamilies. Based on the results of collinearity analyses, the SlFWL genes have a tighter homologous evolutionary relationship with soybean, and these orthologous FWL gene pairs might have the common ancestor. Expression profiling of SlFWL genes show that they were all responsive to abiotic stresses, each subgroup of genes exhibited a different expression trend. Our findings provide a strong foundation for investigating the function and abiotic stress responses of the SlFWL family genes.

Simplified Roux-en-Y reconstruction after laparoscopic radical distal gastrectomy for gastric cancer.

Background: Although there were a variety of strategies for the alimentary tract reconstruction of patients with gastric cancer who underwent laparoscopic radical distal gastrectomy, it remains controversial regarding which procedure is optimal. We developed a simple technique for Roux-en-Y reconstruction during laparoscopic surgery and evaluated its technical feasibility and safety. Methods: Seventy-one cases of modified Roux-en-Y reconstructions after laparoscopic radical distal gastrectomy were consecutively performed in our hospital, from November 2020 to March 2022. A retrospective review of medical data was conducted. Intraoperative and postoperative outcomes, including operation time and incidence of postoperative complications, were collected and analyzed. Results: All procedures of laparoscopic distal gastrectomy with D2 lymph node dissection were successfully completed without any intraoperative complication. The mean number of retrieved lymph node was 38.8 ± 10.6. Mean operative time was 223.5 ± 42.4 min, whereas intraoperative blood loss was 102.2 ± 96.3 ml. No postoperative mortality was recorded. Six patients (8.5%) experienced postoperative complications and were managed conservatively. In addition, only two patients (2.8%) required rehospitalization during a median short-term follow-up period of 6 months. Conclusions: The modified method is a simple and safe approach for laparoscopic radical distal gastrectomy.

Epidemiology and Antibiogram of Riemerella Anatipestifer Isolated from Waterfowl Slaughterhouses in Taiwan.

INTRODUCTION: Laryngeal swab samples collected from three waterfowl slaughterhouses in central Taiwan were cultured and suspected isolates of Riemerella anatipestifer were identified by API 20NE and 16S rDNA PCR. MATERIAL AND METHODS: Serum agglutination was used for serotyping, and antimicrobial susceptibility was tested. RESULTS: Seventy-six R. anatipestifer isolates were detected, and the prevalences in the ducks and geese were 12.3% (46/375) and 8.0% (30/375), respectively. The positive isolation rates were 65.6% for all arriving waterfowl, 76.0% for birds in the holding area, 1.6% for defeathered carcasses, but zero for degummed carcasses. A PCR examination detected R. anatipestifer in the slaughtering area frequently. Serotype B was dominant in both duck (34.8%) and goose (46.7%) isolates, but the wide serotype distribution may very well impede vaccination development. All isolates were resistant to colistin, and 79.7% were resistant to more than three common antibiotics. CONCLUSION: The results proved that most ducks had encountered antibiotic-resistant R. anatipestifer in rearing, which suggests that the bacterium circulates in asymptomatic waterfowl. It is worth noting that most waterfowl farms were found to harbour R. anatipestifer, and contaminated slaughterhouses are a major risk factor in its spread. Effective prevention and containment measures should be established there to interrupt the transmission chain of R. anatipestifer.

Effects of propofol and sevoflurane on aquaporin-4 and aquaporin-9 expression in patients performed gliomas resection.

Post-operative cerebral edema is a threat for patients performed gliomas resection. Some studies have shown that general anesthesia drugs, such as, propofol had neuroprotective effect. Aquaporin-4 (AQP4) and Aquaporin-9 (AQP9) play an important role in maintaining brain water homeostasis under various conditions. The aim of this study was to compare the effect of propofol or sevoflurane on expression of AQP4 and AQP9 in patients performed gliomas resection. 30 patients performed gliomas resection were included in this study. The patients were randomly divided into two groups: propofol group and sevoflurane group. Fresh human gliomas specimens were obtained and hematoxylin eosin (HE) staining, immunohistochemical staining and Western blot analysis were used for observation of the expression of AQP4 and AQP9. The immunohistochemical staining of the sections showed that the percentage of AQP4 positive cells in the propofol group (14.3±4.61%) was significantly lower than that in sevoflurane group (37.3±10.01%) (n=15, P<0.05). There was no significant difference in the percentage of AQP9 positive cells in propofol group and sevoflurane group (25.8±2.67 versus 28.1±7.81%, n=15, P>0.05). Western blot analysis confirmed the immunohistochemistry results. AQP4 protein level in propofol group was significantly lower than that in sevoflurane group (1.4±0.13 versus 1.7±0.12, P<0.05). Western blot analysis did not show any difference of expression of AQP9 protein between the propofol group and sevoflurane group (2.0±0.13 versus 2.1±0.13, P>0.05, n=6). AQP4 expression was lower in patients of propofol group than that in sevoflurane group. Our results suggested that propofol could inhibit the expression of AQP4.

Propofol prevents neuronal mtDNA deletion and cerebral damage due to ischemia/reperfusion injury in rats.

Propofol is a commonly used intravenous anesthetic that has been demonstrated to be neuroprotective against cerebral ischemia-reperfusion (I/R) injury. It remains unclear whether this protective effect has any relationship with the prevention of neuronal mitochondrial deoxyribonucleic acid (mtDNA) deletion. In this study, 81 Wistar rats were randomly divided into three groups (n = 27 each): sham (S group), ischemia/reperfusion (I/R group), or propofol (P group). Cerebral ischemia was induced by clamping the bilateral common carotid arteries for 10 min. A polymerase chain reaction (PCR) was conducted to determine mtDNA deletion. The mitochondrial membrane potential (MMP) changes were detected via microplate reader. The neuronal ultrastructure was visualized via electron microscope. MMP significantly decreased after I/R (P<0.05 compared with the S group). Severe damage to the ultrastructure of neuronal mitochondria was observed in cerebral I/R injury. When propofol (1.0mg/kg/min) was administered intravenously for 1h prior to the induction of I/R, the neuronal structure and MMP were well preserved, and mtDNA deletion was reduced after ischemia/reperfusion injury compared with the I/R group (P<0.05). These data suggested that propofol prevented mtDNA deletion and preserved a normal structure and MMP, which are important for normal mitochondrial function and increase neuronal resistance to I/R injury.