Effects of variations in soil water potential,depth of N placement,and cultivar on postanthesis N uptake by wheat

This study was conducted to investigate the influence of soil water potential, depth of N placement, timing, and cultivar on uptake of a small dose of labeled N applied after anthesis by wheat (Triticum aestivum L.) Understanding postanthesis N accumulation should allow better control of grain protein concentration through proper manipulation of inputs. Two hard, red spring-wheat cultivars were planted in early and late fall each yr of a 2-yr field experiment. Less than 1 kg N ha^–1 as K ¹⁵NO₃ was injected into the soil at two depths: shallow (0.05 to 0.08 m) and deep (0.15 to 0.18 m). In both years an irrigation was applied at anthesis, and injections of labeled N were timed 4, 12, and 20 days after anthesis (DAA). Soil water potential was estimated at the time of injection. Mean recovery of ¹⁵N in grain and straw was 57% of the ¹⁵N applied. Recovery did not differ between the high-protein (Yecora Rojo) and the low-protein (Anza or Yolo) cultivars. Mean recovery from deep placement was 60% versus only 54% from shallow placement (p < 0.01). Delaying the time of injection decreased mean recovery significantly from 58% at 4 DAA to 54% at 20 DAA. This decrease was most pronounced in the shallow placement, where soil drying was most severe. Regressions of recovery on soil water potential of individual cultivar x yr x planting x depth treatments were significant only under the driest conditions. Stepwise regression of ¹⁵N recovery on soil water potential and yield parameters using data from all treatments of both years resulted in an equation including soil water potential and N yield, with a multiple correlation coefficient of 0.64. The translocation of ¹⁵N to grain was higher (0.89) than the nitrogen harvest index (0.69), and showed a highly significant increase with increase in DAA. This experiment indicates that the N uptake capacity of wheat remains reasonably constant between 4 and 20 DAA unless soil drying is severe.     

Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum)

Protein, amino acids and ammonium were the main forms of soluble soil nitrogen in the soil solution of a subtropical heathland (wallum). After fire, soil ammonium and nitrate increased 90- and 60-fold, respectively. Despite this increase in nitrate availability after fire, wallum species exhibited uniformly low nitrate reductase activities and low leaf and xylem nitrate. During waterlogging soil amino acids increased, particularly γ-aminobutyric acid (GABA) which accounted for over 50% of amino nitrogen. Non-mycorrhizal wallum species were significantly (P < 0.05) ¹⁵N-enriched (0.3–4.3‰) compared to species with mycorrhizal associations (ericoid-type, ecto-, va-mycorrhizal) which were strongly depleted in ¹⁵N (-6.3 to -1.8‰). Lignotubers and roots had δ¹⁵N signatures similar to that of the leaves of respective species. The exceptions were fine roots of ecto-, ecto/va-, and ericoid type mycorrhizal species which were enriched in ¹⁵N (0.1–2.4‰). The 5¹⁵N signatures of δ¹⁵N_{total soil N} and δ¹⁵N_{soil NH4+} were in the range 3.7–4.5‰, whereas δ¹⁵N_{soil NO3?} was significantly (P < 0.05) more enriched in ¹⁵N (9.2–9.8‰). It is proposed that there is discrimination against ¹⁵N during transfer of nitrogen from fungal to plant partner. Roots of selected species incorporated nitrogen sources in the order of preference: ammonium > glycine > nitrate. The exception were proteoid roots of Hakea (Proteaceae) which incorporated equal amounts of glycine and ammonium.     

Analysis of the developmental expression of small VCP-interacting protein and its interaction with steroidogenic acute regulatory protein in Leydig cells

Small VCP-interacting protein (SVIP) is a 9-kDa protein that is composed of 76 amino acids, and it plays a role in the endoplasmic reticulum-associated protein degradation (ERAD) pathway. Recent studies have shown that SVIP is an androgen-responsive protein and its expression is regulated by androgens. Because no data are available regarding the cellular localization and expression of SVIP in the mouse testis, where androgens are highly expressed, immunohistochemistry and western blotting were performed. In the fetal testis, we found that moderate but consistent staining of SVIP is present in the cytoplasm of Leydig cells. In prepubertal and adult life, SVIP remains present in Leydig cells as well as in the cytoplasm of some peritubular and Sertoli cells. From postnatal day 15 onward, SVIP is strongly expressed in the cytoplasm of Leydig cells.Furthermore, TM3, MA-10 Leydig and Sertoli cell lines were also used to evaluate the expression of SVIP. To identify the interacting partners, such as steroidogenic acute regulatory (STAR) protein, colocalization studies were performed by fluorescence microscopy, showing that STAR colocalized with SVIP in the adult mouse testis. The expression changes of STAR were studied by using SVIP siRNAs in Leydig cell line cultures. Depletion of SVIP resulted in decreased expression of STAR. Additionally, the number and size of lipid droplets were significantly increased in SVIP-depleted Leydig cells. Taken together, our data identify SVIP as a marker of Leydig cell lineage and as a regulator of STAR protein expression and lipid droplet status in Leydig cells.     

USP15 promotes the apoptosis of degenerative nucleus pulposus cells by suppressing the PI3K/AKT signalling pathway

ObjectivesDegenerative disc disease is characterized by an enhanced breakdown of its existing nucleus pulposus (NP) matrix due to the dysregulation of matrix enzymes and factors. Ubiquitin‐specific protease 15 (USP15) is reported to be abnormal in certain human diseases. However, its role in NP degeneration remains unclear. Therefore, we aimed to explore the function of USP15 in degenerative NP cell specimens.MethodsWe induced gene silencing and overexpression of USP15 in degenerative NP cells using RNA interference (RNAi) and a lentiviral vector, respectively. qRT‐PCR and Western blotting were used to determine gene and protein expression levels. Cell apoptosis was analysed via flow cytometry. Protein interaction was examined by performing a co‐immunoprecipitation assay. Furthermore, the PI3K inhibitor LY294002 and agonist IGF‐1 were used to investigate the link between USP15 and AKT in NP degeneration.ResultsWe found that USP15 was up‐regulated in degenerative NP cells and that its overexpression accelerated the process of apoptosis. Moreover, USP15 expression levels negatively correlated with AKT phosphorylation in degenerative NP cells. Furthermore, targeting and silencing USP15 with miR‐338‐3p and studying its interaction with FK506‐binding protein 5 (FKBP5) revealed enhancement of FKBP5 ubiquitination, indicating that USP15 is a component of the FKBP5/AKT signalling pathway in degenerative NP cells.ConclusionsOur results show that USP15 exacerbates NP degradation by deubiquitinating and stabilizing FKBP5. This in turn results in the suppression of AKT phosphorylation in degenerative NP cells. Therefore, our study provides insights into the understanding of USP15 function as a potential molecule in the network of NP degeneration.     

结直肠癌患者血清GDF-15、G-CSF水平与临床病理特征及预后的关系

摘要 目的：探究结直肠癌血清生长分化因子-15（GDF-15）、粒细胞集落刺激因子（G-CSF）水平与患者临床病理参数、预后的关系,并分析其对结直肠癌的诊断价值。方法：采集结直肠癌患者、结直肠腺瘤患者及健康体检志愿者的血清样本,酶联免疫吸附测定（ELISA）实验检测血清GDF-15、G-CSF;分析结直肠癌患者血清GDF-15、G-CSF水平与患者临床病理参数的关系;Kaplan Meier生存曲线分析血清GDF-15、G-CSF水平与患者预后的关系;受试者工作特征曲线（ROC）分析血清GDF-15、G-CSF水平对结直肠癌的诊断价值。结果：结直肠癌患者血清GDF-15、G-CSF水平高于结直肠腺瘤患者及健康体检志愿者（均P<0.05）;血清GDF-15水平与肿瘤直径、分化程度、远处转移及TNM分期相关（均P<0.05）;血清G-CSF水平与肿瘤分化程度、远处转移及TNM分期相关（均P<0.05）;Kaplan Meier生存曲线结果显示,血清GDF-15低表达、G-CSF低表达患者的术后5年总生存率及中位生存时间均分别高于血清GDF-15高表达、G-CSF高表达患者（均P<0.05）;ROC分析结果表明,血清GDF-15、G-CSF有较好的诊断结直肠癌的价值,血清GDF-15、G-CSF联合应用的敏感度、特异度分别为0.876、0.863。结论：结直肠癌患者血清GDF-15、G-CSF水平升高,且均与患者病情恶性进展、不良预后相关;血清GDF-15、G-CSF是诊断结直肠癌的潜在指标。     

The advent of de novo proteins for cancer immunotherapy

Engineered proteins are revolutionizing immunotherapy, but advances are still needed to harness their full potential. Traditional protein engineering methods use naturally existing proteins as a starting point, and therefore, are intrinsically limited to small alterations of a protein's natural structure and function. Conversely, computational de novo protein design is free of such limitation, and can produce a virtually infinite number of novel protein sequences, folds, and functions. Recently, we used de novo protein engineering to create Neoleukin-2/15 (Neo-2/15), a protein mimetic of the function of both interleukin-2 (IL-2) and interleukin-15 (IL-15). To our knowledge, Neo-2/15 is the first de novo protein with immunotherapeutic activity, and in murine cancer models, it has demonstrated enhanced therapeutic potency and reduced toxicity compared to IL-2. De novo protein design is already showcasing its tremendous potential for driving the next wave of protein-based therapeutics that are explicitly engineered to treat disease.