应用气-质联用仪测定三种螺旋藻中的甾醇成分

应用GLC/MS联用仪对室内培养的钝顶螺旋藻(Spirulina platensis (Nordstedt) Geitler)、极大螺旋藻(S.maxima (Stechell & Gardiner) Geitler)和盐泽螺旋藻(S.subsalsa Oerst)的甾醇成分进行了测定。从钝顶螺旋藻和盐泽螺旋藻中共分出11个相同的甾醇组分:胆甾醇、胆甾烷醇、芸苔甾醇、麦角甾醇、海绵甾醇、菜子甾醇、豆甾醇、24-乙基-Δ~(5,7,22)-胆甾醇、β-谷甾醇、异岩藻甾醇和4α,23,24-三甲基Δ~(5,22)-胆甾醇;从极大螺旋藻中只分离出8个甾醇组分。其中胆甾醇含量最高。4α,23,24-三甲基-Δ~(5,22)-胆甾醇为蓝藻中首次报导。     

The association between sociodemographic,hormonal, tubo-ovarian factors and bacterial count in Chlamydia and Mycoplasma infections with infertility

Aim: To determine if there is an association between the Chlamydia and Mycoplasma infections with socio-demographic and clinical factors, and also with infertility. Methods: We conducted a study on 100 infertile married women and 100 control group, and collected data on the socio-demographic, hormonal and tubo-ovarian factors. The results of the endocervical swabs were analyzed for Mycoplasma and Chlamydia infection, the bacterial counts were also determined. Results: The percentage positivity to infection was significantly more among the infertile group compared to the control group, and also significantly more among the age group <30 years old. The positivity for infection with Chlamydia and/or Mycoplasma was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Further sub-analysis of the infertile group showed that positivity to Chlamydia and/or Mycoplasma infection was significantly correlated to hormonal factors, ovarian factors, irregular menstruation, and previous abortion. Regression analysis showed that hormonal, ovarian factors, and irregular menstruation were the most significant factors in the positivity to Chlamydia and Mycoplasma infection. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Conclusion: Infection to Chlamydia and Mycoplasma is associated to younger age (?30 years old), and occurs in the infertile women. There is an interplay between infection in younger women, irregular menstruation, hormonal, and tubo-ovarian factors with infertility. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion.     

Membrane Chaperone SecDF Plays a Role in the Secretion of Listeria monocytogenes Major Virulence Factors

Listeria monocytogenes is a Gram-positive human intracellular pathogen that infects diverse mammalian cells. Upon invasion, L. monocytogenes secretes multiple virulence factors that target host cellular processes and promote infection. It has been presumed, but was not empirically established, that the Sec translocation system is the primary mediator of this secretion. Here, we validate an important role for SecDF, a component of the Sec system, in the secretion of several critical L. monocytogenes virulence factors. A ΔsecDF mutant is demonstrated to exhibit impaired membrane translocation of listeriolysin O (LLO), PlcA, PlcB, and ActA, factors that mediate L. monocytogenes phagosomal escape and spread from cell to cell. This impaired translocation was monitored by accumulation of the factors on the bacterial membrane and by reduced activity upon secretion. This defect in secretion is shown to be associated with a severe intracellular growth defect of the ΔsecDF mutant in macrophages and a less virulent phenotype in mice, despite normal growth in laboratory medium. We further show that SecDF is upregulated when the bacteria reside in macrophage phagosomes and that it is necessary for efficient phagosomal escape. Taken together, these data support the premise that SecDF plays a role as a chaperone that facilitates the translocation of L. monocytogenes virulence factors during infection.     

Inhibition of yeast adenylate cyclase by antibodies to ras p21.

Monoclonal antibody Y13-259 to ras p21 was shown to bind to the highly conserved residues in the region 63-73 and to neutralize ras action in the Saccharomyces cerevisiae adenylate cyclase system. Inhibition of adenylate cyclase activity in isolated membranes by antibody Y13-259 occurred after a lag period of 6 min. This lag corresponded to the time necessary for binding of antibody Y13-259 to the membranes in a ras-dependent manner. The mechanism of inhibition appeared to be steric in nature because antibody Y13-259 neutralized ras p21 bound to a stable GTP analogue. Monoclonal antibodies Y13-4 and Y13-128 also inhibited yeast adenylate cyclase activity, and the epitopes for both the these antibodies were localized to ras region 65-75. However, the ras residues essential for binding of antibodies Y13-4 and Y13-128 to ras p21 (positions 65, 66, 68 and 75) were different from those essential for binding of antibody Y13-259 (positions 63, 65, 66, 67, 70 and 73). These results indicate that residues 63-75 constitute a major neutralizing epitope on ras p21.     

Crystallization of the aspartylprotease from the human immunodeficiency virus, HIV-1

The aspartylprotease of the human immunodeficiency virus HIV-1 (NY5) has been crystallized in a form suitable for x-ray diffraction analysis. The crystals are tetragonal bipyramids and produce an x-ray diffraction pattern that exhibits the symmetry associated with space group P4(1)2(1)2 (or its enantiomorph, P4(3)2(1)2). The unit cell parameters are a = b = 50.3 A, c = 106.8 A, alpha = beta = gamma = 90 degrees; measurable diffraction intensities are observed to a resolution of 2.5 A. Density measurements indicate one molecule of 9,400 daltons/asymmetric unit. The symmetry of this space group could accommodate the proposed active dimer species of the protease if the 2-fold axis were coincident with one of the crystallographic 2-fold axes.     

Role of GPR40 in fatty acid action on the beta cell line INS-1E

GPR40 is a G protein-coupled receptor expressed preferentially in beta cells, that has been implicated in mediating free fatty acid-stimulated insulin release. GPR40 RNAi impaired the ability of palmitic acid (PA) to increase both insulin secretion and intracellular calcium ([Ca2+]i). The PA-dependent [Ca2+]i increase was attenuated by inhibitors of Galphaq, PLC, and SERCA. Thus GPR40 activates the Galphaq pathway, leading to release of Ca2+ from the ER. Yet the GPR40-dependent [Ca2+]i rise was dependent on extracellular Ca2+ and elevated glucose, and was blocked by inhibition of L-type calcium channels (LTCC) or opening of the K(ATP) channel; this suggests that GPR40 promotes Ca2+ influx through up-regulation of LTCC pre-activated by glucose and membrane depolarization. Taken together, the data indicate that GPR40 mediates the increase in [Ca2+]i and insulin secretion through the Galphaq-PLC pathway, resulting in release of Ca2+ from the ER and leading to up-regulation of Ca2+ influx via LTCC.     

Inheritance of fertility in broiler chickens

Background

The fertility of a chicken''s egg is a trait which depends on both the hen that lays the egg and on her mate. It is also known that fertility of an individual changes over the laying period.

Methods

Longitudinal models including both random genetic and permanent environmental effects of both the female and her male mate were used to model the proportion of fertile eggs in a pedigree broiler population over the ages 29-54 weeks.

Results

Both the male and the female contribute to variation in fertility. Estimates of heritability of weekly records were typically 7% for female and 10% for male contributions to fertility. Repeatability estimates ranged from 24 to 33%, respectively. The estimated genetic variance remained almost constant for both sexes over the laying period and the genetic correlations between different ages were close to 1.0. The permanent environment components increased substantially towards the end of the analyzed period, and correlations between permanent environment effects at different ages declined with increasing age difference The heritability of mean fertility over the whole laying period was estimated at 13% for females and 17% for males. A small positive correlation between genetic effects for male and female fertility was found.

Conclusion

Opportunities to improve fertility in broiler stocks by selection on both sexes exist and should have an impact throughout the laying period.     

The role ofSaccharomyces cerevisiae Cdc40p in DNA replication and mitotic spindle formation and/or maintenance

Successful progression through the cell cycle requires the coupling of mitotic spindle formation to DNA replication. In this report we present evidence suggesting that, inSaccharomyces cerevisiae, theCDC40 gene product is required to regulate both DNA replication and mitotic spindle formation. The deduced amino acid sequence ofCDC40 (455 amino acids) contains four copies of a β-transducin-like repeat. Cdc40p is essential only at elevated temperatures, as a complete deletion or a truncated protein (deletion of the C-terminal 217 amino acids in thecdc40-1 allele) results in normal vegetative growth at 23°C, and cell cycle arrest at 36°C. In the mitotic cell cycle Cdc40p is apparently required for at least two steps: (1) for entry into S phase (neither DNA synthesis, nor mitotic spindle formation occurs at 36°C and (2) for completion of S-phase (cdc40::LEU2 cells cannot complete the cell cycle when returned to the permissive temperature in the presence of hydroxyurea). The role of Cdc40p as a regulatory protein linking DNA synthesis, spindle assembly/maintenance, and maturation promoting factor (MPF) activity is discussed.