一株虾池来源的螺旋拟柱孢藻藻株的分离鉴定及重金属离子Cu~(2+)、Cd~(2+)和Pb~(2+)对其生长的影响

【目的】探讨凡纳滨对虾养殖水体中入侵蓝藻拟柱孢藻的生长生理特性。【方法】从汕头澄海人工对虾养殖池分离纯化藻株,通过形态及其16SrRNA基因鉴定,之后在CT与BG11两种蓝藻通用培养基的基础上优化最佳培养条件,最后分析了不同浓度的3种重金属离子即Cu~(2+)(0–0.8 mg/L)、Cd~(2+)(0–4 mg/L)和Pb~(2+)(0–80 mg/L)对藻株生长的影响。【结果】澄海虾池来源的分离纯化藻株形态呈卷曲螺旋型,16S rRNA基因序列与多株其他来源的拟柱孢藻相似度均达98%以上。实验室培养,藻株最佳生长状态的培养条件是在BG11培养基的基础上调整氮浓度及氮磷比分别为N 62 mg/L,N︰P=9︰1,在此条件下,藻丝生物量可达(0.632±0.170)×107/L,藻丝比平均生长速率最高为(0.063±0.001)/d。本分离藻株活体对重金属Cu~(2+)、Cd~(2+)和Pb~(2+)具有一定的耐受性,其耐受浓度范围分别为0–0.2、0–0.5和1–40 mg/L,其中,Cu~(2+)和Cd~(2+)对藻的生长具有抑制作用,而且此抑制作用随着金属离子剂量的增加及作用时间的延长更加显著,Cu~(2+)和Cd~(2+)对藻体的半数抑制浓度(96 h EC50)分别为0.125和0.551 mg/L;而浓度范围为0–80 mg/L的Pb~(2+)对藻体的生长则表现为低剂量(≤40 mg/L)呈促进,高剂量(≥80 mg/L)则抑制。【结论】从凡纳滨对虾养殖池中分离鉴定出一株形态呈螺旋型的拟柱孢藻,命名为螺旋拟柱孢藻(Cylindrospermopsis raciborskii helix),本藻株活体能够在一定浓度的Cu~(2+)、Cd~(2+)和Pb~(2+)中生长,为螺旋拟柱孢藻活藻生物吸附重金属离子而改善虾池水体环境提供了可能性。     

A varying‐coefficient generalized odds rate model with time‐varying exposure: An application to fitness and cardiovascular disease mortality

Varying‐coefficient models have become a common tool to determine whether and how the association between an exposure and an outcome changes over a continuous measure. These models are complicated when the exposure itself is time‐varying and subjected to measurement error. For example, it is well known that longitudinal physical fitness has an impact on cardiovascular disease (CVD) mortality. It is not known, however, how the effect of longitudinal physical fitness on CVD mortality varies with age. In this paper, we propose a varying‐coefficient generalized odds rate model that allows flexible estimation of age‐modified effects of longitudinal physical fitness on CVD mortality. In our model, the longitudinal physical fitness is measured with error and modeled using a mixed‐effects model, and its associated age‐varying coefficient function is represented by cubic B‐splines. An expectation‐maximization algorithm is developed to estimate the parameters in the joint models of longitudinal physical fitness and CVD mortality. A modified pseudoadaptive Gaussian‐Hermite quadrature method is adopted to compute the integrals with respect to random effects involved in the E‐step. The performance of the proposed method is evaluated through extensive simulation studies and is further illustrated with an application to cohort data from the Aerobic Center Longitudinal Study.     

Construction of a sensitive pyrogen-testing cell model by site-specific knock-in of multiple genes

A pyrogen test is crucial for evaluating the safety of drugs and medical equipment, especially those involved in injections. As existing pyrogen tests, including the rabbit pyrogen test, the limulus amoebocyte lysate (LAL) test and the monocyte activation test have limitations, development of new models for pyrogen testing is necessary. Here we develop a sensitive cell model for pyrogen test based on the lipopolysaccharides (LPS) signal pathway. TLR4, MD2, and CD14 play key roles in the LPS-mediated pyrogen reaction. We established a new TLR4/MD2/CD14-specific overexpressing knock-in cell model using the CRISPR/CAS9 technology and homologous recombination to detect LPS. Stimulation of our TLR4/CD14/MD2 knock-in cell line model with LPS leads to the release of the cytokines IL-6 and TNF-alpha, with a detection limit of 0.005 EU/ml, which is greatly lower than the lower limit of 0.015 EU/ml detected by the Tachypleus amebocyte lysate (TAL) assay.     

CircPUM1 promotes the malignant behavior of lung adenocarcinoma by regulating miR-326

CircRNAs are reported to be implicated in the development of lung cancer. This study focused on assessing the expression, functions and molecular mechanism of circPUM1 in lung adenocarcinoma. Here, it showed that circPUM1 is significantly upregulated in both lung adenocarcinoma cell lines and tissues. Furthermore, silencing of circPUM1 impaired the proliferation, migration and invasion ability, and increased apoptosis in A549?cells. Nevertheless, overexpression of circPUM1 in SPC-A1 cells has the opposite effect. Silencing of circPUM1 inhibits the tumorigenesis in nude mice. Mechanistically, circPUM1 could sponge miR-326 and promote the expression of its downstream proteins Cyclin D1 and Bcl-2. In summary, this present study revealed that circPUM1 functions as an oncogene to promote the tumorigenesis of lung adenocarcinoma through circPUM1/miR-326/Cyclin D1 and Bcl-2 axis. This indicates that circPUM1 may act as a potential therapeutic target for lung adenocarcinoma.     

Circular RNA circRNA_15698 aggravates the extracellular matrix of diabetic nephropathy mesangial cells via miR-185/TGF-β1

Circular RNAs (circRNAs) are a novel type of noncoding RNAs that modulate the pathogenesis of multiple diseases. Nevertheless, the role of circRNAs in diabetic nephropathy (DN) pathogenesis is still ambiguous. In the current study, our team aims to investigate the expression profiles of circRNAs in DN and identify the function of circRNA on mesangial cells. CircRNAs microarray analysis revealed dysregulated circRNA in db/db DN mice, and circRNA_15698 was validated to be upregulated in both db/db mice and mouse mesangial cells (SV40-MES13) that were exposed to high glucose (25 mM) using real-time polymerase chain reaction. Loss-of-functional experiments showed that circRNA_15698 knockdown significantly inhibited the expression levels of collagen type I (Col. I), collagen type IV (Col. IV), and fibronectin. Moreover, the cellular localization of circRNA_15698 was mainly in the cytoplasm. Bioinformatics tools and luciferase reporter assay confirmed that circRNA_15698 acted as a ‘sponge’ of miR-185, and then positively regulated the transforming growth factor-β1 (TGF-β1) protein expression, suggesting a circRNA_15698/miR-185/TGF-β1 pathway. Further validation experiments validated that circRNA_15698/miR-185/TGF-β1 promoted extracellular matrix (ECM)-related protein synthesis. In summary, our study preliminarily investigates the role of circRNAs in mesangial cells and ECM accumulation, providing a novel insight for DN pathogenesis.     

Benzo(a)pyrene inhibits endometrial cell apoptosis in early pregnant mice via the WNT5A pathway

Benzo(a)pyrene (BaP) is an endocrine-disrupting pollutant present in various aspects of daily life, and studies have demonstrated that BaP exerts reproductive toxicity. We previously showed that BaP damages endometrial morphology and decreases the number of implantation sites in early pregnant mice, but the mechanisms underlying these effects remain unclear. The endometrial function is crucial for implantation, which is associated with endometrial cell apoptosis. In this study, we focused on the effect of BaP on endometrial cell apoptosis and the role of WNT signaling during this process. Pregnant mice were gavaged with corn oil (control group) or 0.2 mg·kg⁻¹·day ⁻¹ BaP (treatment group) from Days 1 to 6 of pregnancy. BaP impaired endometrial function by decreasing the expression of HOXA10 and BMP2, two markers of receptivity and decidualization. WNT5A and β-catenin were activated in the BaP group. BaP affected the expression of apoptosis-related proteins and inhibited the apoptosis of endometrial stromal cells. In vitro, human endometrial stromal cells (HESCs) were treated with different concentrations of BaP (dimethyl sulfoxide (DMSO); 5, 10 µM). WNT5A and β-catenin were also upregulated in the BaP treatment group. HESC apoptosis was restrained by BaP. Inhibiting WNT5A by SFRP5 partially restored the effect of BaP on apoptosis. In summary, these results suggested that BaP exposure during early pregnancy activates WNT5A/β-catenin signaling pathway, which inhibits the endometrial cell apoptosis and potentially destroys endometrial function.     

Long term experimental drought alters community plant trait variation,not trait means,across three semiarid grasslands

Plant and Soil - Mechanisms by which soil pH affects rice growth await further elucidation. We have used a Systems Biology approach to elucidate the nature of the damage caused by extreme pH to...     

Effects of Melatonin on Growth,Physiology and Gene Expression in Rice Seedlings Under Cadmium Stress

Melatonin (MLT) is a hormonal substance found in many organisms and can improve plant stress resistance. In this study, the japonica rice variety Y32 and indica rice variety NJ6 were cultivated in hydroponics under different concentrations of CdCl₂ at the two-leaf stage. The growth, physiological and biochemical responses of the seedlings and the expression of cadmium (Cd)-related genes under exogenous melatonin (MLT) treatment were assessed. The results indicated that Cd stress destroyed the dynamic balance between reactive oxygen species (ROS) production and removal, resulting in ROS accumulation, membrane lipid peroxidation, and impaired growth and development. Following the application of exogenous MLT to rice seedlings, increases in plant biomass including both underground and above-ground areas were observed. MLT also scavenged the inhibition of superoxide dismutase (SOD) and peroxidase (POD) in a concentration dependent manner in response to Cd stress. Catalase (CAT) activity and malondialdehyde (MDA) expression also decreased following MLT treatment. Amongst the six Cd-related genes assessed, five genes were down-regulated and one was up-regulated in response to MLT treatment. Taken together, these data demonstrate that MLT improves the resilience of rice seedlings at the biochemical, physiological, and molecular levels, and diminishes the damage caused by Cd stress.     

High-resolution imaging of rhizosphere oxygen (O2) dynamics in Potamogeton crispus: effects of light,temperature and O2 content in overlying water

Plant and Soil - Radial oxygen loss (ROL) for macrophytes is intimately involved in their survival and growth, thus detailed characterizations of ROL and its implication for geochemical processes...     

Paecilomyces variotii extracts (ZNC) enhance plant immunity and promote plant growth

Plant and Soil - There are growing concerns regarding the restoration of karst rocky desertification (KRD) areas. However, the soil conditions and its residing microorganisms, which are essential...