Targeted disruption of LH receptor gene revealed the importance of uterine LH signaling

Numerous previous studies have demonstrated that LH and hCG can directly regulate several uterine functions. We investigated in the present study, whether uterine phenotype in LH receptor knockout animals resulted also from the absence of direct actions of LH in the uterus. The phenotype consisted of marked growth reduction of uterus, decreased thickness of endometrial and myometrial layers, number of endometrial glands, height of luminal epithelium and vascular space. Analysis of uterine gene expression by mouse genome U74Av2 Affymetrix genechips revealed a differential expression of 155 genes by more than 3-fold (range 3-53-fold) between null and wild-type animals. Of these, 89 genes decreased and 66 increased in uterus of null animals. Semi-quantitative RT-PCR confirmed the differential expression of several selected genes. The decreased genes can be clustered into 18 functional families and the increased into 15 functional families. Semi-quantitative RT-PCR, Western blotting and immunocytochemistry demonstrated a decreased expression of ERbeta, PR-A, PR-B and AR in uterus of null animals as compared with wild-type siblings. Twenty-one-day estradiol and progesterone replacement therapy did not normalize the decrease in the number of endometrial glands and several genes that either decreased or increased in expression. The partial success of therapy suggests that direct LH actions could be required to completely normalize the uterus. In summary, findings on the knockout model reaffirm that LH and hCG control uterine functions directly as well as indirectly through increasing ovarian synthesis of steroid hormones and both actions are required for normal uterine biology.     

A unique AtSar1D-AtRabD2a nexus modulates autophagosome biogenesis in Arabidopsis thaliana

In eukaryotes, secretory proteins traffic from the endoplasmic reticulum (ER) to the Golgi apparatus via coat protein complex II (COPII) vesicles. Intriguingly, during nutrient starvation, the COPII machinery acts constructively as a membrane source for autophagosomes during autophagy to maintain cellular homeostasis by recycling intermediate metabolites. In higher plants, essential roles of autophagy have been implicated in plant development and stress responses. Nonetheless, the membrane sources of autophagosomes, especially the participation of the COPII machinery in the autophagic pathway and autophagosome biogenesis, remains elusive in plants. Here, we provided evidence in support of a novel role of a specific Sar1 homolog AtSar1d in plant autophagy in concert with a unique Rab1/Ypt1 homolog AtRabD2a. First, proteomic analysis of the plant ATG (autophagy-related gene) interactome uncovered the mechanistic connections between ATG machinery and specific COPII components including AtSar1d and Sec23s, while a dominant negative mutant of AtSar1d exhibited distinct inhibition on YFP-ATG8 vacuolar degradation upon autophagic induction. Second, a transfer DNA insertion mutant of AtSar1d displayed starvation-related phenotypes. Third, AtSar1d regulated autophagosome progression through specific recognition of ATG8e by a noncanonical motif. Fourth, we demonstrated that a plant-unique Rab1/Ypt1 homolog AtRabD2a coordinates with AtSar1d to function as the molecular switch in mediating the COPII functions in the autophagy pathway. AtRabD2a appears to be essential for bridging the specific AtSar1d-positive COPII vesicles to the autophagy initiation complex and therefore contributes to autophagosome formation in plants. Taken together, we identified a plant-specific nexus of AtSar1d-AtRabD2a in regulating autophagosome biogenesis.

Autophagy is a conserved catabolic process characterized by the de novo generation of a double-membrane structure called an autophagosome with a fundamental function in the bulk turnover of cytoplasmic components, including proteins, RNAs, and organelles. Genetic studies in yeast have elucidated the molecular machinery of autophagy, whereby 42 autophagy-related (ATG) genes have been identified (1–3). These ATG genes are highly conserved among eukaryotes but often have multiple isoforms in other higher organisms, in particular in sessile plants. Albeit increasing understanding on the molecular function of Atg proteins in acting hierarchically on the phagophore assembly site (PAS) to produce autophagosomes, the origin of the autophagosomal membrane remains unclear in higher eukaryotes. Furthermore, the dedication of other membranes and machineries in the autophagy pathway remains under investigation.Plant autophagy is known to play important roles in the sessile lifestyle of plants, participating in seed germination, seedling establishment, plant development, hormone responses, lipid metabolism, and reproductive development (4). Plant autophagy research is advancing with findings not only on the counterparts of the yeast/mammalian Atg proteins but also dealing with some plant-unique factors functioning in different steps of autophagosome biogenesis, thereby uncovering novel mechanisms that might or might not be conserved in nonplant species (5). More interestingly, higher plants possess multiple protein isoforms of ATG machinery, whose functional heterogeneity in the autophagy pathway has only recently been unveiled (6).The coat protein complex II (COPII) machinery consists of five cytosolic components: the small GTPase Sar1, the inner coat protein dimer Sec23-Sec24, and the outer coat proteins Sec13-Sec31. These proteins are essential for COPII-coated vesicle formation, which buds from specialized regions of the ER, namely ER exit sites (ERESs) (7). Under nutrient-rich conditions, COPII vesicles mediate anterograde ER to Golgi transport. However, increasing evidence from yeast and mammals suggests that the COPII machinery or even COPII vesicles themselves may contribute to autophagosome formation when cells are starved for nutrients (8–16). Gene duplication events have occurred substantially in sessile plants during evolution, and the importance of distinct paralogs in environmental stress adaptation during plant development has been implied (17). Arabidopsis encodes multiple COPII paralogs in its genome, including five Sar1s, seven Sec23s, three Sec24s, two Sec13s, and two Sec31s (17). Increasing numbers of studies have pinpointed the functional diversity and importance of distinct COPII paralogs in ER protein export (18–23). Nonetheless, the mechanism by which COPII vesicles are redirected to the autophagy pathway upon nutrient starvation, and their roles in autophagosome biogenesis, remains unclear. Furthermore, the participation of specific COPII paralogs in autophagy regulation remains unknown in plants.Here, we report on a role of a specific Sar1 homolog, AtSar1d, that modulates plant autophagosome biogenesis in concert with AtRabD2a. Large-scale proteomic analysis of the ATG interactome has revealed possible mechanistic connections between the ATG machinery and specific COPII components in plants. Cellular and biochemical analyses have shown that the dominant negative (DN) mutant of AtSar1d (AtSar1dDN) specifically perturbs YFP-ATG8 vacuolar degradation upon autophagic induction. Consistently, a transfer DNA (T-DNA) insertion mutant of AtSar1d exhibited starvation-related phenotypes. Notably, AtSar1d regulates autophagosome progression through specific recognition of ATG8e by a previously uncharacterized noncanonical motif. We further identify a plant-unique Rab1/Ypt1 homolog AtRabD2a that colocalizes with AtSar1d and ATG8 upon starvation by transient expression in Arabidopsis protoplasts. A DN mutant of AtRabD2a (AtRabD2aNI) perturbs autophagy flux, while AtRabD2a is indispensable for bridging the AtSar1d-positive COPII vesicles with the ATG1 complex, thus contributing to autophagosome biogenesis in plants. Our study therefore unequivocally demonstrates that the plant-specific COPII machinery regulates autophagosome biogenesis and sheds light on the evolutionary importance of gene duplication events in the plant autophagy pathway.     

立普妥小剂量治疗老年人高脂血症的研究

目的观察阿托伐他汀钙（立普妥）10mg日一次服用的降脂疗效及安全性。方法66例老年高脂血症患者接受立普妥10mg每日一次治疗,疗程8周。入组前及第8周末检测血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）。每4周询问服药反应并进行实验室检测。结果治疗8周后,患者血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）较入组前分别降低了28.92%、27.10%、34.07%（P均〈0.01）,其中降低TC的总有效率为94.74%,降低TG的总有效率为59.52%。高密度脂蛋白胆固醇（HDL-C）较入组前升高14.00%（P〈0.01）,升高HDL-C的总有效率为53.96%。结论立普妥10mg每日一次服用,安全有效,对改善老年人高脂血症有显著疗效。     

Participation of the S4 voltage sensor in the Mg2+-dependent activation of large conductance (BK) K+ channels

The S4 transmembrane segment is the primary voltage sensor in voltage-dependent ion channels. Its movement in response to changes in membrane potential leads to the opening of the activation gate, which is formed by a separate structural component, the S6 segment. Here we show in voltage-, Ca2+-, and Mg2+-dependent, large conductance K+ channels that the S4 segment participates not only in voltage- but also Mg2+-dependent activation. Mutations in S4 and the S4-S5 linker alter voltage-dependent activation and have little or no effect on activation by micromolar Ca2+. However, a subset of these mutations in the C-terminal half of S4 and in the S4-S5 linker either reduce or abolish the Mg2+ sensitivity of channel gating. Cysteine residues substituted into positions R210 and R213, marking the boundary between S4 mutations that alter Mg2+ sensitivity and those that do not, are accessible to a modifying reagent [sodium (2-sulfonatoethyl)methane-thiosulfonate] (MTSES) from the extracellular and intracellular side of the membrane, respectively, at -80 mV. This implies that interactions between S4 and a cytoplasmic domain may be involved in Mg2+-dependent activation. These results indicate that the voltage sensor is critical for Mg2+-dependent activation and the coupling between the voltage sensor and channel gate is a converging point for voltage- and Mg2+-dependent activation pathways.     

同型半胱氨酸及其相关酶基因多态性与糖尿病周围神经病变的关系

研究对象为 2型糖尿病 (DM )有周围神经病变组 (60例 )、2型DM无周围神经病变组 (4 6例 )和正常对照组 (5 0例 )。分别测定 3组血浆同型半胱氨酸 (Hcy) ,血清叶酸、维生素B12 水平及Hcy代谢关键酶亚甲基四氢叶酸还原酶 (MTHFR)的基因型。结果显示 ,高Hcy及低叶酸、维生素B12 水平与 2型DM患者伴发周围神经病变相关 ,而MTHFR的基因多态性只与DM有关而与DM周围神经病变无相关性。     

马来酸曲美布汀治疗肠易激综合征对比研究

目的探讨马来酸曲美布汀对肠易激综合征的治疗效果。方法将诊断为肠易激综合征（IBS）的97例患者随机分成试验组（47例）和对照组（50例），试验组给予马来酸曲美布汀，对照组使用复合维生素B作为安慰剂，两组疗程均为6周，治疗期间均停用其他药物，分别于治疗前及治疗的第2、4、6周及随访8、12周末进行症状评价及评分。结果试验组治疗后积分明显下降，治疗前后比较差异有非常显著性（P〈0．01）；对照组积分下降不明显，治疗前后比较差异无显著性（P〉0．05）；治疗4周后两组间比较，试验组积分下降较对照组明显，差异有非常显著性（P〈0．01）；治疗后两组疗效比较，试验组在2周后有效率达34％，8周和12周时分别达到83％和82％，疗效明显高于对照组，差异有非常显著性（P〈0．01）。结论马来酸曲美布汀对难治性功能性消化不良具有良好的治疗作用和安全性。     

多层螺旋CT门静脉血管成像与内镜对食管、胃静脉曲张诊断的比较研究

目的对比研究多层螺旋CT门静脉血管成像(CTP)和内镜对食管、胃静脉曲张的诊断。方法采用16排多层螺旋CT门静脉血管成像,对57例临床和实验室检查提示门静脉高压的患者进行CTP,观察门静脉及其分支走形、分布,并结合横断面图像仔细观察食管和胃有无静脉曲张,并记录其部位、曲张静脉深浅、观察曲张静脉来源、有无其他部位曲张静脉或其他病理情况。同期对这些病例行胃镜检查,观察食管、胃是否存在静脉曲张及其他病变。结果CTP显示食管及胃静脉曲张病例51例,其中胃底静脉曲张合并食管静脉曲张39例,单纯胃底静脉曲张9例,胃底静脉曲张合并胃体静脉曲张3例。内镜发现食管及胃底静脉曲张46例,其中胃静脉曲张合并食管静脉曲张24例,单纯胃静脉曲张5例,单纯食管静脉曲张17例。CTP可发现内镜无法诊断的肌层或管腔外静脉曲张。结论CTP可清晰显示门静脉高压患者食管、胃底静脉曲张及主要侧支血管的走行、分布。在食管静脉曲张检查方面,CTP与内镜效果相当,CTP有几例假阳性,可作为普通内镜检查的良好补充;对于胃静脉曲张的检查,CTP效果较胃镜敏感,且CTP可清晰显示内镜无法观察的胃腔周围和食管周围静脉曲张。     

Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM

The radial spoke (RS) heads of motile cilia and flagella contact projections of the central pair (CP) apparatus to coordinate motility, but the morphology is distinct for protozoa and metazoa. Here we show the murine RS head is compositionally distinct from that of Chlamydomonas. Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a and Rsph10b, whose orthologs exist in the protozoan RS head. We resolve its cryo-electron microscopy (cryo-EM) structure at 3.2-Å resolution. Our atomic model further reveals a twofold symmetric brake pad-shaped structure, in which Rsph4a and Rsph9 form a compact body extended laterally with two long arms of twisted Rsph1 β-sheets and potentially connected dorsally via Rsph3b to the RS stalk. Furthermore, our modeling suggests that the core complex contacts the periodic CP projections either rigidly through its tooth-shaped Rsph4a regions or elastically through both arms for optimized RS–CP interactions and mechanosignal transduction.

The majority of motile cilia and flagella are composed of nine dynein arm-containing peripheral doublet microtubules (DMTs) surrounding a central pair (CP) of MTs (the “9+2” axoneme). The radial spoke (RS) is a T-shaped protein complex with an orthogonal head pointing toward the CP and a stalk anchored on each A-tubule of the DMTs (1–5). It acts as the mechanochemical transducer between the CP and axonemal dynein arms to regulate flagellar/ciliary motility (6–11). The flagella of Chlamydomonas reinhardtii, a widely used model organism, contain two full-size RSs (RS1 and RS2) in each 96-nm repeat unit of the axoneme. In contrast, motile cilia/flagella of Tetrahymena thermophila and metazoa possess triplet RSs (RS1 to RS3) (2–4, 11). The Chlamydomonas RS is composed of at least 23 subunit proteins (RSP1 to RSP23) (2, 12, 13). Seventeen of them have mammalian homologs (14). Mutations leading to the loss of the entire RS or RS head result in immotile flagella in Chlamydomonas (6–8) but in rotatory ciliary beat in mammals, causing primary ciliary dyskinesia (PCD), a genetic syndrome characterized by recurrent respiratory infections, situs inversus, infertility, and hydrocephalus (4, 15–21).The most striking morphological differences in the RS lie in the RS head, the key structural domain that mediates the mechanosignaling by directly contacting projections of the CP (9–11). The heads of RS1 and RS2 consist of two structurally identical, rotationally symmetric halves that differ largely from that of RS3 (3, 4). Furthermore, their morphologies differ dramatically between protozoa and metazoa. In Chlamydomonas and Tetrahymena, for instance, the heads of RS1 and RS2 are rich in lateral branches that also form a connection between the two heads (2, 4). In contrast, in sea urchin (Strongylocentrotus purpuratus) and human, the heads of RS1 and RS2 resemble a pair of ice skate blades with many fewer interfaces toward the CP (3, 4). Despite the importance of the RS and RS head in cilia/flagella motility, the structural details of the RS and the RS–CP interactions remain poorly understood, especially in mammals.The RS heads have probably been remodeled to comply with both structural and functional alterations of the axoneme during evolution. How the morphological changes occurred, however, remains unclear. The Chlamydomonas RS head is composed of RSP1, -4, -6, -9, and -10 and part (the C terminus) of the stalk component, RSP3. Each of the symmetrical halves of the head contains one copy of these components (2, 10, 22). All the head components have mammalian orthologs (Rsph1, -4a, -6a, -9, -10b, and -3b) (11, 14). In sharp contrast to the markedly reduced surface area of metazoan RS heads, the peptides of human RSPH4A, -6A, and -10B are longer than their Chlamydomonas orthologs by 1.5-, 1.3-, and 4-fold, respectively (11). Only RSPH1 (309 amino acids [aa]) is shorter than RSP1 (814 aa) (11). The lengths of mouse RS head proteins are also similarly changed as their human counterparts (SI Appendix, Fig. S1A). Furthermore, while murine Rsph4a is essential for the head formation of RS1 to RS3 in motile multicilia of the trachea, ependyma, and oviduct (15), Rsph6a is specifically expressed in sperm for their normal flagellar formation (23). RSP4/Rsph4a and RSP6/Rsph6a are paralogs: RSP4 and RSP6 share 48% sequence identity (24), whereas murine Rsph4a is 63% identical to Rsph6a (SI Appendix, Fig. S1B). Sea urchin and Ciona, however, have only one ortholog (11, 25). These results suggest that, unlike the protozoan RS heads, the metazoan ones may not simultaneously contain Rsph4a and Rsph6a. The general shapes of the RS structure in axonemes have been determined by conventional electron microscopy (EM) (26–28) and cryo-electron tomography (cryo-ET) (2–5). Recently, a 15-Å-resolution RS structure of Chlamydomonas was resolved by cryo-EM single-particle analysis (29). The resolutions, however, do not suffice for the delineation of the locations of individual RS subunits.In the present study, by biochemical and structural analyses, we show the murine RS head is both compositionally and morphologically distinct from that of Chlamydomonas. Our study suggests that the RS head has experienced profound remodeling to probably comply with both structural and functional alterations of the axoneme during evolution for coordinated ciliary or flagellar motility.     

Synthesis and Stability of Hydrogen Storage Material Aluminum Hydride

Aluminum hydride (AlH₃) is a binary metal hydride with a mass hydrogen density of more than 10% and bulk hydrogen density of 148 kgH2/m3. Pure aluminum hydride can easily release hydrogen when heated. Due to the high hydrogen density and low decomposition temperature, aluminum hydride has become one of the most promising hydrogen storage media for wide applications, including fuel cell, reducing agents, and rocket fuel additive. Compared with aluminum powder, AlH₃ has a higher energy density, which can significantly reduce the ignition temperature and produce H₂ fuel in the combustion process, thus reducing the relative mass of combustion products. In this paper, the research progress about the structure, synthesis, and stability of aluminum hydride in recent decades is reviewed. We also put forward the challenges for application of AlH₃ and outlook the possible opportunity for AlH₃ in the future.