H2S位于SOS上游参与盐胁迫诱导的拟南芥气孔关闭

以拟南芥野生型、SOS突变体(Atsos1、Atsos2和Atsos3)、H2S合成相关酶L-/D-半胱氨酸脱巯基酶(L-/D-CDes)基因缺失突变体(Atl-cdes和Atd-cdes)和过表达株系(OEL-CDes和OED-CDes)为材料研究了H2S和SOS信号转导途径在盐胁迫诱导拟南芥气孔关闭中的作用及其相互关系。结果表明,盐胁迫能够引起拟南芥叶片H2S含量、L-/D-CDes活性及其基因表达量显著升高,诱导野生型拟南芥和OEL-CDes和OED-CDes叶片气孔关闭,但对Atl-cdes和Atd-cdes气孔开度无显著影响;而H2S清除剂次牛磺酸(hypotaurine,HT)可减弱盐胁迫诱导的拟南芥气孔关闭的作用,表明H2S参与盐胁迫诱导的拟南芥气孔关闭过程。外源H2S诱导野生型拟南芥气孔关闭,但对SOS突变体气孔开度无显著影响;同时盐胁迫下Atsos1、Atsos2和At-sos3亦表现出H2S含量及L-/D-CDes活性显著升高,且与野生型相比,盐胁迫对Atl-cdes和Atd-cdes叶片AtSOS基因表达量无显著影响。表明盐胁迫诱导气孔关闭过程中H2S位于SOS上游。     

The structures of four bombesins and their cloned precursor-encoding cDNAs from acid-solvated skin secretion of the European yellow-bellied toad, Bombina variegata

Four different bombesins (bombesin, His(6)-bombesin, Phe(13)-bombesin and Asp(2)-, Phe(4)-SAP-bombesin) have been identified by a systematic sequencing study of peptides in reverse phase HPLC fractions of the skin secretion of the European yellow-bellied toad, Bombina variegata, that had been solvated in 0.1% (v/v) aqueous trifluoroacetic acid (TFA) and stored frozen at -20°C for 12 years. By using a 3'- and 5'-RACE PCR strategy, the corresponding biosynthetic precursor-encoding cDNAs of all four peptides were cloned from a cDNA library made from the same long-term frozen, acid-solvated skin secretion sample following thawing and lyophilization. Canonical bombesin and His(6)-bombesin are classical bombesin sub-family members, whereas Phe(13)-bombesin and Asp(2)-, Phe(4)-SAP-bombesin, belong to the litorin/ranatensin sub-family of bombesin-like peptides (BLPs). Assignment of these peptides to respective sub-families, was based upon both their primary structural similarities and their comparative pharmacological activities. An interesting observation in this study, was that the nucleotide sequences of the open-reading frames of cloned cDNAs encoding bombesin and its His(6)-substituted analog, were identical except for a single base that was responsible for the change observed at the position 6 residue in the mature peptide from Asn to His. In contrast, the precursor cDNA nucleotide sequences encoding the Phe(13)-bombesins, exhibited 53 base differences. The pharmacological activities of synthetic replicates of each bombesin were compared using two different mammalian smooth muscle preparations and all four peptides were found to be active. However, there were significant differences in their relative potencies.     

The calcium-sensing receptor complements parathyroid hormone-induced bone turnover in discrete skeletal compartments in mice

Although the calcium-sensing receptor (CaSR) and parathyroid hormone (PTH) may each exert skeletal effects, it is uncertain how CaSR and PTH interact at the level of bone in primary hyperparathyroidism (PHPT). Therefore, we simulated PHPT with 2 wk of continuous PTH infusion in adult mice with deletion of the PTH gene (Pth(-/-) mice) and with deletion of both PTH and CaSR genes (Pth(-/-)-Casr (-/-) mice) and compared skeletal phenotypes. PTH infusion in Pth(-/-) mice increased cortical bone turnover, augmented cortical porosity, and reduced cortical bone volume, femoral bone mineral density (BMD), and bone mineral content (BMC); these effects were markedly attenuated in PTH-infused Pth(-/-)-Casr(-/-) mice. In the absence of CaSR, the PTH-stimulated expression of receptor activator of nuclear factor-κB ligand and tartrate-resistant acid phosphatase and PTH-stimulated osteoclastogenesis was also reduced. In trabecular bone, PTH-induced increases in bone turnover, trabecular bone volume, and trabecular number were lower in Pth(-/-)-Casr(-/-) mice than in Pth(-/-) mice. PTH-stimulated genetic markers of osteoblast activity were also lower. These results are consistent with a role for CaSR in modulating both PTH-induced bone resorption and PTH-induced bone formation in discrete skeletal compartments.     

Effect of intranasal arginine vasopressin on human headache

Arginine vasopressin (AVP), a nonapeptide hormone of posterior pituitary, reaches the central nervous system from systemic blood circulation with a difficulty because of the blood–brain barrier (BBB). The interest has been expressed in the use of the nasal route for delivery of AVP to the brain directly, exploiting the olfactory pathway. Our previous study has demonstrated that AVP in the brain rather than the spinal cord and blood circulation plays an important role in rat pain modulation. For understanding the role of AVP on pain modulation in human, the communication tried to investigate the effect of intranasal AVP on human headache. The results showed that (1) AVP concentration in both plasma and cerebrospinal fluid (CSF) increased significantly in headache patients, who related with the headache level; (2) there was a positive relationship between plasma and CSF AVP concentration in headache patients; and (3) intranasal AVP could relieve the human headache in a dose-dependent manner. The data suggested that intranasal AVP, which was delivered to the brain through olfactory region, could treat human headache and AVP might be a potential drug of pain relief by intranasal administration.     

黑腹果蝇细胞谱系分析方法进展

对动物体内单个细胞的谱系进行分析有助于追踪其在发育过程中的作用,但是体内各种组织都是由很多形态、结构、功能各不相同的细胞构成的复杂系统,这种复杂性严重阻碍了对单个细胞的研究。嵌合克隆技术(Mosaic technique)和标记技术(Labeling technique)的出现为这一研究提供了强有力的手段。文章介绍了近几年来黑腹果蝇(Drosophila melanogaster)研究中常用的7种嵌合克隆标记方法,包括FRT介导的有丝分裂重组(FRT-mediated mitotic recombination)、MARCM(Mosaic analysis with a repressible cell marker)、TSG(Twin spotgenerator)、Twin-spot MARCM、Q-MARCM(Q system-based MARCM)、Coupled MARCM和G-TRACE(Gal4technique for real-time and clonal expression)技术,详述了这些技术的原理及应用,并对不同技术进行了对比。运用这些技术研究者可以从单细胞水平进行遗传学标记和操作,特别是在神经系统等复杂系统中追踪单个细胞的发育过程。果蝇中的这些技术也将为其他模式生物追踪细胞谱系提供参考。     

Analysis of the neutral polysaccharide fraction of MCP and its inhibitory activity on galectin-3

The pH-modified citrus pectin (MCP) has been demonstrated to inhibit galectin-3 in cancer progression. The components and structures of MCP related to this inhibition remained unknown. In this paper, we fractionated MCP on DEAE-cellulose column into a homogenous neutral fraction MCP-N (about 20?kDa) and a pectin mixture fraction MCP-A (wide molecular distribution on Sepharose CL-6B chromatography). Both MCP-N and MCP-A inhibited hemagglutination mediated by galectin-3 with minimum inhibition concentration (MIC) 625 and 0.5?μg/ml, respectively. MCP-N was identified to be a type I arabinogalactan (AG-I) with a main chain of β-1→4-galactan. MCP-N was digested by α-L-arabinofuranosidase to give its main chain structure fraction (M-galactan, around 18?kDa), which was more active than the original molecule, MIC 50?μg/ml. The acidic degradation of M-galactan increased the inhibitory activity, MIC about 5 times lower than M-galactan. These results above showed that the functional motif of the β-1→4-galactan fragment might lie in the terminal residues rather than in the internal region of the chain. Therefore, MCP-N and its degraded products might be developed to new potential galectin-3 inhibitors. This is the first report concerning the fractionation of MCP and its components on galectin-3 inhibition. The information provided in this paper is valuable for screening more active galectin-3 inhibitors from natural polysaccharides.     

Systematic investigation of Amphioxus (Branchiostoma floridae) microRNAs

Ascaris lumbricoides and Ascaris suum are parasitic nematodes living in the small intestine of humans and pigs, and can cause the disease ascariasis. For long, there has been controversy as to whether the two ascaridoid taxa represent the same species due to their significant resemblances in morphology. However, the complete mitochondrial (mt) genome data have been lacking for A. lumbricoides in spite of human and animal health significance and socio-economic impact globally of these parasites. In the present study, we sequenced the complete mt genomes of A. lumbricoides and A. suum (China isolate), which was 14,303 bp and 14,311 bp in size, respectively. The identity of the mt genomes was 98.1% between A. lumbricoides and A. suum (China isolate), and 98.5% between A. suum (China isolate) and A. suum (USA isolate). Both genomes are circular, and consist of 36 genes, including 12 genes for proteins, 2 genes for rRNA and 22 genes for tRNA, which are consistent with that of all other species of ascaridoid studied to date. All genes are transcribed in the same direction and have a nucleotide composition high in A and T (71.7% for A. lumbricoides and 71.8% for A. suum). The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. Phylogenetic analyses of A. lumbricoides and A. suum using concatenated amino acid sequences of 12 protein-coding genes, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony) all clustered in a clade with high statistical support, indicating that A. lumbricoides and A. suum was very closely related. These mt genome data and the results provide some additional genetic evidence that A. lumbricoides and A. suum may represent the same species. The mt genome data presented in this study are also useful novel markers for studying the molecular epidemiology and population genetics of Ascaris.     

Effect of a DNA vaccine harboring two copies of inhibin α (1-32) fragments on immune response, hormone concentrations and reproductive performance in rats

The objective was to investigate the effects of a novel DNA vaccine (pcISI) harboring two copies of inhibin α (1-32) fragments on immune response, hormone concentrations and reproductive performance in rats. Female Wistar rats (n = 18 per group) were immunized (twice, 4 wk apart) with 10, 50, or 100 μg (T₁, T₂ and T₃, respectively), of the pcISI plasmid. At 4 wk after the second immunization, plasma antibody titers were higher (P < 0.05) in T₃ than in either T₁ or T₂ (0.341 ± 0.123, 0.236 ± 0.068, and 0.251 ± 0.077, respectively, mean ± SD). Concurrrently, plasma concentrations of FSH and estradiol were highest (P < 0.05) in T₃, and were higher (P < 0.05) in T₁ and T₂ than in control groups. For antibody-positive rats, there was a correlation (P < 0.01) between antibody titer and FSH concentrations after two pcISI immunizations. The number of mature follicles in the T₃ group (46.00 ± 4.65) was higher (P < 0.05) than in two control groups (29.25 ± 3.72 and 27.92 ± 3.48), and also higher (P < 0.05) than in T₁ and T₂ (37.17 ± 4.99 and 38.75 ± 7.09). Antibody-positive rats had more mature ovarian follicles than negative rats (46.75 ± 4.23 vs. 35.60 ± 3.38, P < 0.05). Moreover, litter size and number of placentas were increased (P < 0.05) in the pcISI immunization groups, except for the T₁ group, compared to the control groups. In conclusion, the pcISI DNA vaccine successfully induced a humoral immune response, improved reproductive hormone concentrations, stimulated follicular development, and increased number of placentas and litter size. Furthermore, 100 μg yielded the best immune response.     

Aspergillus niger DLFCC-90 rhamnoside hydrolase, a new type of flavonoid glycoside hydrolase

A novel rutin-α-L-rhamnosidase hydrolyzing α-L-rhamnoside of rutin, naringin, and hesperidin was purified and characterized from Aspergillus niger DLFCC-90, and the gene encoding this enzyme, which is highly homologous to the α-amylase gene, was cloned and expressed in Pichia pastoris GS115. The novel enzyme was classified in glycoside-hydrolase (GH) family 13.