抗菌免疫核糖核酸组份的分离及其活性测定

<正> 抗菌免疫核糖核酸(iRNA)已用于条件致病菌感染的临床治疗,并对其免疫活性做了全面的研究。现已证实iRNA能够诱导特异性抗体的产生和传递特异性的细胞免疫,并能诱生干扰素和白细胞间素Ⅰ、Ⅱ等淋巴因子和单核因子。但制备的iRNA是含有多种RNA种类的混合物,为明确各组份的免疫学功能,我们对iRNA进行了分离,并测定不同组份的免疫活性。     

Cardiac restricted overexpression of kinase-dead mammalian target of rapamycin (mTOR) mutant impairs the mTOR-mediated signaling and cardiac function

Mammalian target of rapamycin (mTOR) is a key regulator for cell growth through modulating components of the translation machinery. Previously, numerous pharmacological studies using rapamycin suggested that mTOR has an important role in regulating cardiac hypertrophic growth. To further investigate this assumption, we have generated two lines of cardiac specific mTOR transgenic mice, kinase-dead (kd) mTOR and constitutively active (ca) mTOR, using alpha-myosin heavy chain promoter. alpha-Myosin heavy chain (alphaMHC)-mTORkd mice had a near complete inhibition of p70 S6k and 4E-BP1 phosphorylation, whereas alphaMHC-mTORca had a significant increase in p70 S6k and 4E-BP1 phosphorylation. Although the cardiac function of alphaMHC-mTORkd mice was significantly altered, the cardiac morphology of these transgenic mice was normal. The cardiac hypertrophic growth in response to physiological and pathological stimuli was not different in alphaMHC-mTORkd and alphaMHC-mTORca transgenic mice when compared with that of nontransgenic littermates. These findings suggest that the mTOR-mediated signaling pathway is not essential to cardiac hypertrophic growth but is involved in regulating cardiac function. Additional analysis of cardiac responses to fasting-refeeding or acute insulin administration indicated that alphaMHC-mTORkd mice had a largely impaired physiological response to nutrient energy supply and insulin stimulation.     

Electron-Microscope Observation on the Pollen Development of Male Sterility Wheat Induced by Ethrel

The pollen development of male sterility wheat induced by Ethrel was studied in comparison with that of normal wheat by transmission and scanning electron-microscope. The results obtained are summarized as follows: 1. The primary morphological changes of abortive wheat pollen after treatment with Ethrel took place in the vacuole stage. The materials of cytoplasm were rarefied. All kinds of the cell organelles and vacuoles became degenerated and disorganized. Inside a small number of cell nuclei, chromatin granules coagulated irregularly. The number and the activity of the Ubisch bodices became reduced evidently. 2. In the mature stage, the differences between the treated wheat and normal wheat became even more striking. The normal pollens were spherical in sharp, and full of starch granules. The treated pollen were monstrous. There was a large empty vacuole in every abortive pollen cell, in which the starch granules were smaller and fewer than these in the normal ones. The nuclei and cytoplasm in some of the abortive pollens were degenerated, leaving only the cell walls. 3. Under scanning electron microscope, it was discovered that the normal wheat pollen were spherical or oval. The germinated pores jutted. The round-openings of the pores could be clearly seen. The abortive pollen induced by Ethrel looked like some shrunken balls, and became deformed and were blocked up. 4. On discussion of the mechanism of the Ethrel-induced male sterility in wheat, the authors suggest that special attention should be paid to the changes of the Ubisch bodies and the vacuoles.     

Immunogens Modeling a Fusion-Intermediate Conformation of gp41 Elicit Antibodies to the Membrane Proximal External Region of the HIV Envelope Glycoprotein

The membrane proximal external region (MPER) of the gp41 subunit of the HIV-1 envelope glycoprotein (Env) contains determinants for broadly neutralizing antibodies and has remained an important focus of vaccine design. However, creating an immunogen that elicits broadly neutralizing antibodies to this region has proven difficult in part due to the relative inaccessibility of the MPER in the native conformation of Env. Here, we describe the antigenicity and immunogenicity of a panel of oligomeric gp41 immunogens designed to model a fusion-intermediate conformation of Env in order to enhance MPER exposure in a relevant conformation. The immunogens contain segments of the gp41 N- and C-heptad repeats to mimic a trapped intermediate, followed by the MPER, with variations that include different N-heptad lengths, insertion of extra epitopes, and varying C-termini. These well-characterized immunogens were evaluated in two different immunization protocols involving gp41 and gp140 proteins, gp41 and gp160 DNA primes, and different immunization schedules and adjuvants. We found that the immunogens designed to reduce extension of helical structure into the MPER elicited the highest MPER antibody binding titers, but these antibodies lacked neutralizing activity. The gp41 protein immunogens also elicited higher MPER titers than the gp140 protein immunogen. In prime-boost studies, the best MPER responses were seen in the groups that received DNA priming with gp41 vectors followed by gp41 protein boosts. Finally, although titers to the entire protein immunogen were similar in the two immunization protocols, MPER-specific titers differed, suggesting that the immunization route, schedule, dose, or adjuvant may differentially influence MPER immunogenicity. These findings inform the design of future MPER immunogens and immunization protocols.     

Metagenomic analysis for the microbial consortium of anaerobic CO oxidizers

Metagenomics analysis has been applied to identify the dominant anaerobic microbial consortium of the carbon monoxide (CO) oxidizers in anaerobic sludge. Reads from the hypervariable V6 region in the bacterial 16s rDNA were aligned and finally clustered into operational taxonomic units (OTUs). The OTUs from different stages in anaerobic CO condition were classified. Alphaproteobacteria, clostridia, betaproteobacteria and actinobacteria were the most abundant groups, while alphaproteobacteria, betaproteobacteria and actinobacteria were variable groups. CO consumption and production efficiency of the microbial consortium were studied. Semi-continuous trials showed that these anaerobic CO oxidizers formed a stable microbial community, and the CO conversion rate was at over 84%, with the highest CO consumption activity of 28.9 mmol CO/g VSS●day and methane production activity at 7.6 mmol CH₄/g VSS●day during six cycles.     

QTL analysis of cotton fiber length in advanced backcross populations derived from a cross between <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> and <Emphasis Type="Italic">G. mustelinum</Emphasis>

Key message

QTLs for fiber length mapped in three generations of advanced backcross populations derived from crossing Gossypium hirsutum and Gossypium mustelinum showed opportunities to improve elite cottons by introgression from wild relatives.

Abstract

The molecular basis of cotton fiber length in crosses between Gossypium hirsutum and Gossypium mustelinum was dissected using 21 BC₃F₂ and 12 corresponding BC₃F_2:3 and BC₃F_2:4 families. Sixty-five quantitative trait loci (QTLs) were detected by one-way analysis of variance. The QTL numbers detected for upper-half mean length (UHM), fiber uniformity index (UI), and short fiber content (SFC) were 19, 20, and 26 respectively. Twenty-three of the 65 QTLs could be detected at least twice near adjacent markers in the same family or near the same markers across different families/generations, and 32 QTLs were detected in both one-way variance analyses and mixed model-based composite interval mapping. G. mustelinum alleles increased UHM and UI and decreased SFC for five, one, and one QTLs, respectively. In addition to the main-effect QTLs, 17 epistatic QTLs were detected which helped to elucidate the genetic basis of cotton fiber length. Significant among-family genotypic effects were detected at 18, 16, and 16 loci for UHM, UI, and SFC, respectively. Six, two, and two loci showed genotype?×?family interaction for UHM, UI and SFC, respectively, illustrating complexities that might be faced in introgression of exotic germplasm into cultivated cotton. Co-location of many QTLs for UHM, UI, and SFC accounted for correlations among these traits, and selection of these QTLs may improve the three traits simultaneously. The simple sequence repeat (SSR) markers associated with G. mustelinum QTLs will assist breeders in transferring and maintaining valuable traits from this exotic source during cultivar development.

     

microRNA-95 knockdown inhibits epithelial–mesenchymal transition and cancer stem cell phenotype in gastric cancer cells through MAPK pathway by upregulating DUSP5

This study investigated the role of microRNA-95 (miR-95) in gastric cancer (GC) and to elucidate the underlying mechanism. Initially, bioinformatic prediction was used to predict the differentially expressed genes and related miRNAs in GC. miR-95 and DUSP5 expression was altered in GC cell line (MGC803) to evaluate their respective effects on the epithelial–mesenchymal transition (EMT) process, cellular processes (cell proliferation, migration, invasion, cell cycle, and apoptosis), cancer stem cell (CSC) phenotype, as well as tumor growth ability. It was further predicted in bioinformatic prediction and verified in GC tissue and cell line experiments that miR-95 was highly expressed in GC. miR-95 negatively regulated DUSP5, which resulted in the MAPK pathway activation. Inhibited miR-95 or overexpressed DUSP5 was observed to inhibit the levels of CSC markers (CD133, CD44, ALDH1, and Lgr5), highlighting the inhibitory role in the CSC phenotype. More important, evidence was obtained demonstrating that miR-95 knockdown or DUSP5 upregulation exerted an inhibitory effect on the EMT process, cellular processes, and tumor growth. Together these results, miR-95 knockdown inhibited GC development via DUSP5-dependent MAPK pathway.     

OsAGAP, an ARF-GAP from rice, regulates root development mediated by auxin in Arabidopsis

Arf (ADP-ribosylation factor) proteins, which mediate vesicular transport, have little or no intrinsic GTPase activity. They rely on the action of GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs) for their function. In the present study the OsAGAP gene in rice, which encoded a protein with predicted structure similar to ArfGAP, was identified. The purified OsAGAP-GST fusion protein was able to stimulate the GTPase activity of rice Arf. Furthermore, OsAGAP can rescue the defect of vesicular transport in the yeast gcs1 delta glo3 delta double-mutant cells. Transgenic Arabidopsis with OsAGAP constitutively expression showed reduced apical dominance, shorter primary roots, increasing number of longer adventitious roots. Many of the phenotypes can be phenocopied by treatment of exogenous indoleacetic acid level (IAA) in wild-type plants. Determination of whole-plant IAA level showed that there is a sharp increase of free IAA in OsAGAP transgenic Arabidopsis seedlings. In addition, removal of the 4-day-old shoot apex could inhibit the adventitious root formation in the transgenic seedlings. These results suggest OsAGAP, an ARF-GAP of rice, maybe involved in the mediation of plant root development by regulating auxin level.     

黄芩苷对家兔离体子宫平滑肌的作用

目的:观察黄芩苷对家兔离体子宫平滑肌收缩的作用及其与Ca2+的关系.方法:制作常规离体家兔子宫平滑肌肌条,考察黄芩苷对子宫肌条反应的影响.结果:(1)黄芩苷(5-10mmol-L-1)剂量依赖抑制子宫平滑肌收缩;(2)黄芩苷对催产素及高K去极化液中Ca2+所致的离体子宫平滑肌收缩均呈剂量依赖性抑制;使CaC12累积量-效曲线非平行性右移,最大效应下降,呈非竞争性抑制;(3)且对子宫平滑肌依细胞内、外Ca2+两种收缩成分均呈抑制作用.结论:黄芩苷对家兔离体子宫平滑肌条的抑制作用,可能与其拮抗Ca2+有关.