[Effects of Cadmium on Ca2+ and IRE1 signaling pathway in GC2 spd cells].

OBJECTIVE: To study the effects of cadmium on autophagy in germ cells (GC-2 spd cells) through Ca2+ and IRE1 pathway. METHODS: The viability of GC-2 spd cells was determined using a CCK-8 assay to establish the concentration of cadmium treating . MDC staining was employed to assess autophagosome formation. Laser confocal microscopy and flow cytometry were utilized to measure cytoplasmic and endoplasmic reticulum (ER) Ca2+ levels. Western blot was conducted to evaluate the expression levels of proteins associated with the IRE1 signaling pathway and autophagy. RESULTS: As the concentration of cadmium increased, cell viability gradually decreased. The concentrations of cadmium were determined to be 2.5, 5, and 10 µmol/L. Compared with the control group, the IOD values of MDC fluorescence intensity within the cadmium group were all elevated (P<0.05), accompanied by elevated ratios of autophagy markers LC3-II/LC3-I and up-regulation of Beclin-1 protein expression (P<0.05). Cytoplasm Ca2+ levels gradually increased, while ER Ca2+ levels decreased (P<0.05). The expression of IP3R protein, the ER Ca2+ release pathway, was up-regulated (P<0.05). Additionally, the expressions of IRE1, XBP1s, CHOP, and GRP78 were up-regulated in the cadmium group (P<0.05). CONCLUSION: Cadmium exposure can induce dysregulation of calcium homeostasis in GC-2spd cells, activates the ER stress-induced IRE1 signaling pathway, and ultimately induces the occurrence of autophagy in GC-2spd cells.

Prevalence/potential risk factors for motoric cognitive risk and its relationship to falls in elderly Chinese people: a cross-sectional study.

BACKGROUND AND PURPOSE: Motoric cognitive risk syndrome (MCR) is characterized by slow walking speed and subjective memory complaints (SMCs). This study investigated the prevalence and potential risk factors of MCR and its association with falls in Chinese community-dwelling older adults. METHODS: The analysis was based on data from the Rugao Longevity and Aging Study (RuLAS). MCR was defined as the presence of both SMCs and slow walking speed in participants free of major neurocognitive disorders. SMCs were determined according to a positive answer to the question 'Do you feel you have more problems with memory than most?' in the 15-item Geriatric Depression Scale. Slow walking speed was defined as one standard deviation or more below the mean value for patients' age and sex. Data on falls were derived from a standardized questionnaire. RESULTS: The prevalence of SMCs, slow walking speed and MCR in the RuLAS cohort (N = 1592) was 51.9%, 15.6% and 8.3%, respectively. After adjusting for other covariates, an occupation of farming (odds ratio [OR] 2.358, 95% confidence interval [CI] 1.007-5.521, p = 0.048), history of cerebrovascular disease (OR 2.215, 95% CI 1.032-4.752, p = 0.041) and hospitalization (OR 2.008, 95% CI 1.120-3.602, p = 0.019) were risk factors for MCR. Binary logistic regression analysis indicated that the risk of falls was increased by MCR (OR 1.547, 95% CI 1.009-2.371), SMC (OR 1.308, 95% CI 1.003-1.707) and slow walking speed (OR 1.442, 95% CI 1.030-2.017). CONCLUSIONS: Early identification of potential risk factors of MCR can prevent the occurrence of adverse health events such as falls in the elderly.

Transcriptional Regulator PhlH Modulates 2,4-Diacetylphloroglucinol Biosynthesis in Response to the Biosynthetic Intermediate and End Product.

Certain strains of biocontrol bacterium Pseudomonas fluorescens produce the secondary metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) to antagonize soilborne phytopathogens in the rhizosphere. The gene cluster responsible for the biosynthesis of 2,4-DAPG is named phlACBDEFGH and it is still unclear how the pathway-specific regulator phlH within this gene cluster regulates the metabolism of 2,4-DAPG. Here, we found that PhlH in Pseudomonas fluorescens strain 2P24 represses the expression of the phlG gene encoding the 2,4-DAPG hydrolase by binding to a sequence motif overlapping with the -35 site recognized by σ70 factors. Through biochemical screening of PhlH ligands we identified the end product 2,4-DAPG and its biosynthetic intermediate monoacetylphloroglucinol (MAPG), which can act as signaling molecules to modulate the binding of PhlH to the target sequence and activate the expression of phlG Comparison of 2,4-DAPG production between the ΔphlH, ΔphlG, and ΔphlHG mutants confirmed that phlH and phlG impose negative feedback regulation over 2,4-DAPG biosynthesis. It was further demonstrated that the 2,4-DAPG degradation catalyzed by PhlG plays an insignificant role in 2,4-DAPG tolerance but contributes to bacterial growth advantages under carbon/nitrogen starvation conditions. Taken together, our data suggest that by monitoring and down-tuning in situ levels of 2,4-DAPG, the phlHG genes could dynamically modulate the metabolic loads attributed to 2,4-DAPG production and potentially contribute to rhizosphere adaptation.IMPORTANCE 2,4-DAPG, which is synthesized by biocontrol pseudomonad bacteria, is a broad-spectrum antibiotic against bacteria, fungi, oomycetes, and nematodes and plays an important role in suppressing soilborne plant pathogens. Although most of the genes in the 2,4-DAPG biosynthetic gene cluster (phl) have been characterized, it is still not clear how the pathway-specific regulator phlH is involved in 2,4-DAPG metabolism. This work revealed the role of PhlH in modulating 2,4-DAPG levels by controlling the expression of 2,4-DAPG hydrolase PhlG in response to 2,4-DAPG and MAPG. Since 2,4-DAPG biosynthesis imposes a metabolic burden on biocontrol pseudomonads, it is expected that the fine regulation of phlG by PhlH offers a way to dynamically modulate the metabolic loads attributed to 2,4-DAPG production.

[Function of auxin-binding protein gene during cucumber fruit development].

A cDNA fragment that encodes auxin-binding protein 1 was amplified by, reverse polymerase chain reaction from ovary of cucumber. Its expression signals were weak in the ovary of 1 d before anthesis, while got strong in 2, 4 and 6 d after pollination. Among the unpollinated ovary of 2 d after anthesis, those that got enlarged had strong expression signals; the others that were wilting had weak signals. This indicated that auxin-binding protein 1 gene possibly play a role in cucumber fruit development. When auxin-binding protein 1 gene of Arabidopsis was transformed into cucumber, the parthenocarpic rate of transgenic plants was 31.7%, higher than the control. This result showed that the sensibility to auxin was increased in transgenic plants.