鸡冠花种子营养成分的研究

鸡冠花种子可供食用和药用。作者采用常规方法系统地分析测定了其营养成分,并和一些谷类,豆类食物进行了比较。结果显示,鸡冠花种子含各种营养成分:蛋白质、脂肪、碳水化合物、膳食纤维、氨基酸、维生素、无机元素等,不仅含量丰富且高于谷类。这为开发利用鸡冠花种子提供了科学依据。     

孕酮受体在雌性小鼠生殖系统中的分布及RU486对其影响

用免疫细胞化学ＬＳＡＢ法,兔抗人孕酮受体抗体（适用于小鼠）显示小鼠卵巢、输卵管、子宫和阴道中的孕酮受体。结果显示：未注射ＲＵ４８６的动物的子宫与阴道内孕酮受体丰富,输卵管中含量较少,卵巢中未见阳性反应物质。ＲＵ４８６注射４天后,子宫与阴道中孕酮受体明显减少;注射后７天,输卵管、子宫和阴道都为阴性反应。该结果显示了孕酮受体在雌性小鼠生殖系统内的分布特点,提示ＲＵ４８６封闭孕酮受体的最佳时间为用药后第７天。     

The Adenylyl Cyclase Inhibitor MDL-12,330A Potentiates Insulin Secretion via Blockade of Voltage-Dependent K+ Channels in Pancreatic Beta Cells

Objective

Adenylyl cyclases (ACs) play important role in regulating pancreatic beta cell growth, survival and secretion through the synthesis of cyclic AMP (cAMP). MDL-12,330A and SQ 22536 are two AC inhibitors used widely to establish the role of ACs. The goal of this study was to examine the effects of MDL-12,330A and SQ 22536 on insulin secretion and underlying mechanisms.

Methods

Patch-clamp recording, Ca²⁺ fluorescence imaging and radioimmunoassay were used to measure outward K⁺ currents, action potentials (APs), intracellular Ca²⁺ ([Ca²⁺]_i) and insulin secretion from rat pancreatic beta cells.

Results

MDL-12,330A (10 µmol/l) potentiated insulin secretion to 1.7 times of control in the presence of 8.3 mmol/l glucose, while SQ 22536 did not show significant effect on insulin secretion. MDL-12,330A prolonged AP durations (APDs) by inhibiting voltage-dependent K⁺ (K_V) channels, leading to an increase in [Ca²⁺]_i levels. It appeared that these effects induced by MDL-12,330A did not result from AC inhibition, since SQ 22536 did not show such effects. Furthermore, inhibition of the downstream effectors of AC/cAMP signaling by PKA inhibitor H89 and Epac inhibitor ESI-09, did not affect K_V channels and insulin secretion.

Conclusion

The putative AC inhibitor MDL-12,330A enhances [Ca²⁺]_i and insulin secretion via inhibition of K_V channels rather than AC antagonism in beta cells, suggesting that the non-specific effects is needed to be considered for the right interpretation of the experimental results using this agent in the analyses of the role of AC in cell function.     

Expression and characteristics of rice xylanase inhibitor OsXIP,a member of a new class of antifungal proteins

It has been hypothesized that xylanase inhibitors play important roles in plant defense against microbial pathogens. Currently, there is little information available about xylanase inhibitor OsXIP in rice and its gene expression. We cloned a xylanase inhibitor gene OsXIP from rice (Oryza sativa L. cv. Nipponbare) genomic DNA. To determine the function of OsXIP, we generated OsXIP-overexpressing transgenic rice plants. The transgenic plants had significantly higher OsXIP expression and showed enhanced defense response to Magnaporthe oryzae compared to the wild-type plants. The results also showed that the increased OsXIP expression was accompanied by the up-regulation of pathogenesisrelated genes. To clarify the OsXIP expression pattern, a ProOsXIP::GUS vector was constructed and transgenic plants were obtained. GUS staining results revealed that OsXIP showed organ-specific expressions in rice plants. OsXIP was primarily expressed in the roots and in the veins, but it was weakly expressed in the leaves. Analyses of the OsXIP expression in response to biotic and abiotic stresses indicated that it was drastically induced by biotic stresses and methyl jasmonate treatment. OsXIP, a member of a new class of antifungal proteins, may function as a barrier that prevents the cell wall degradation by xylanases excreted by fungal pathogens. The OsXIP was found to be a stressresponsive gene and it could take part in plant defense via a JA-mediated signaling pathway.     

CMTM6 inhibits tumor growth and reverses chemoresistance by preventing ubiquitination of p21 in hepatocellular carcinoma

Hepatocellular carcinoma is one of the most common malignancies and has a poor prognosis. The ubiquitin-proteasome pathway is required for the degradation of most short-lived proteins. CMTM6 has been implicated in the progression of various tumors, but its biological function and the underlying molecular mechanisms in HCC are still unknown. In this study, we found that the expression of CMTM6 was significantly reduced in HCC and predicted better prognosis of HCC patients. Through in vitro and in vivo experiments, CMTM6 was shown to inhibit the proliferation of HCC cells by blocking the G1/S phase transition. Mechanistically, CMTM6 interacted with p21 and prevented its ubiquitination mediated by SCF^SKP2, CRL4^CDT2 and APC/C^CDC20 in a cell-cycle–independent manner. As a result, CMTM6 stabilized p21 protein, leading to the inactivation of pRB/E2F pathway. Additionally, CMTM6 sensitized HCC cells to doxorubicin and cisplatin, positively correlated with better clinical outcomes of the transarterial chemoembolization (TACE) treatment for postoperative recurrence. Taken together, our study reports a novel mechanism by which p21 can be stabilized by CMTM6 and pinpoints a crucial role of the CMTM6-p21 axis in suppressing the progression of HCC and sensitizing patients with postoperative recurrence to TACE treatment.Subject terms: Cancer therapeutic resistance, Tumour biomarkers, Liver cancer     

Magnetic Ganoderma Lucidum Spores(mGLS):A Novel Regulatable Targeted Drug Delivery System

In the past decades,many materials have been studied as carriers for targeted drug delivery.However,there is a need for utilizable and selective carrier materia...     

A PAM-free CRISPR/Cas12a ultra-specific activation mode based on toehold-mediated strand displacement and branch migration

CRISPR (clustered regularly interspaced short palindromic repeats) technology has achieved great breakthroughs in terms of convenience and sensitivity; it is becoming the most promising molecular tool. However, only two CRISPR activation modes (single and double stranded) are available, and they have specificity and universality bottlenecks that limit the application of CRISPR technology in high-precision molecular recognition. Herein, we proposed a novel CRISPR/Cas12a unrestricted activation mode to greatly improve its performance. The new mode totally eliminates the need for a protospacer adjacent motif and accurately activates Cas12a through toehold-mediated strand displacement and branch migration, which is highly universal and ultra-specific. With this mode, we discriminated all mismatch types and detected the EGFR T790M and L858R mutations in very low abundance. Taken together, our activation mode is deeply incorporated with DNA nanotechnology and extensively broadens the application boundaries of CRISPR technology in biomedical and molecular reaction networks.