麻叶千里光抗菌化学成分的研究(Ⅲ)

以革兰氏阳性菌金黄色葡萄球菌（Staphylococcus aureus）、枯草芽孢杆菌（Bacillus subtilis）和阴性菌大肠杆菌（Escherichia coli）为受试菌,采用体外抑菌圈法追踪抗菌活性部分。利用各种色谱技术对正丁醇萃取部分进行分离纯化,根据理化性质和谱学数据进行结构鉴定。从麻叶千里光的水提醇沉物的正丁醇萃取部分分离得到3个化合物：苄基-O-α-L-广吡喃阿拉伯糖基（1→6）-β-D-吡喃葡糖苷（1）、（6S,9S）-6-羟基-3-酮-α-紫罗兰醇-9-O-β-D-葡糖苷（2）和（6S,9R）-6-羟基-3-酮-α-紫罗兰醇-9-O-β-D-葡糖苷（3）。它们均为首次从该属植物中分离得到。     

Isolation and characterization of polymorphic microsatellite loci in the boll weevil,Anthonomus grandis Boheman (Coleoptera: Curculionidae)

The boll weevil (Anthonomus grandis Boheman) is a major insect pest of cotton in North America. Dispersal activity poses a threat to ongoing eradication efforts in the US, but little is known about the frequency of long‐distance migration. Nuclear molecular markers are needed to assess gene flow in relation to geographical distance. A biotin‐enrichment strategy was employed to develop microsatellite markers for the boll weevil. Of 23 loci isolated, 14 were polymorphic with three to 10 alleles per locus. Twelve of the polymorphic loci showed Mendelian inheritance and are likely to be useful in population genetics studies.     

Ceramide Inhibits Cell Proliferation through Akt/PKB Inactivation and Decreases Melanin Synthesis in Mel‐Ab Cells

Ceramide is a bioactive sphingolipid that mediates a variety of cell functions. However, the effects of ceramide on cell growth and the melanogenesis of melanocytes are not known. In the present study, we investigated the actions of cell‐permeable ceramide and its possible role in the signaling pathway of a spontaneously immortalized mouse melanocyte cell line, Mel‐Ab. Our results show that C₂‐ceramide inhibits DNA synthesis in Mel‐Ab cells and G361 human melanoma cells in a dose‐dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase. To investigate the ceramide signaling pathway, we studied whether C₂‐ceramide is able to influence extracellular signal‐regulated kinase (ERK) and/or Akt/protein kinase B (PKB) activation. We demonstrated that phosphorylated Akt/PKB is decreased by C₂‐ceramide, whereas phosphorylated ERK was only slightly affected. Therefore, the C₂‐ceramide‐induced inactivation of Akt/PKB may be closely related to the reduced cell proliferation of Mel‐Ab cells. Furthermore, we assessed the effects of C₂‐ceramide on the pigmentation of Mel‐Ab cells. The results obtained showed that the melanin content of cells was significantly reduced by C₂‐ceramide at concentrations in the range of 1–10 μM, and that the pigmentation‐inhibiting effect of C₂‐ceramide is much greater than that of kojic acid at 1–100 μM. In addition, we found that the activity of tyrosinase is reduced by C₂‐ceramide treatment. Our results demonstrate that C₂‐ceramide reduces the pigmentation of Mel‐Ab cells by inhibiting tyrosinase activity.     

Effects of auditory stimuli on the lifespan of Drosophila melanogaster

It is well known that music can have calming effects on humans, other mammals and birds. Reducing environmental stress or enhancing the resistance to certain stressors has been shown to extend lifespan in several organisms. Evidence also suggests that mild temporary stress may also enhance stress resistance and ultimately slow the aging process. This study explored the possibility that music may influence the lifespan of the fruit fly Drosophila melanogaster, possibly by affecting responses to stress. Flies received either background sounds (control), or background sounds supplemented with music (experimental). The experimental group had classical music playing constantly at an average of 20 dB above background sound. The median lifespan of females receiving music was 42 days compared to the median of 45 days without music, but the difference was not significant. For males median lifespans were 42 days with music exposure, and 47 days without music and the difference was significant. These results suggest that exposure to classical music decreased the lifespan of male Drosophila. Both experimental and control populations showed age-dependent increases in mortality, indicating that music affects the normal aging process rather than showing overt toxicity. These results suggest that certain auditory stimuli may be stressful and can be used as insect management.     

Contractile Proteins of a Benthic Fish. III. Subunit Composition of Myosin

SYNOPSIS. Ultracentrifugal and electrophoretic experiments arereported on the subunit composition of myosin from skeletalmuscle of a benthic fish, Coryphaenoides species. Coryphaenoidesmyosin undergoes extensive association in concentrated KGI solutionsat neutral pH, but sedimentation equilibrium experiments indicatethe presence of a small fraction (3%) of monomeric myosin withmolecular weight approximately 440,000. At pH 11, some of theaggregated myosin is dissociated, and monomeric myosin is itselfdissociated into a heavy component (410,000 mol wt) and a lightcomponent (14,000 mol wt) that comprises 5–7% of the protein.The lialkali component of Coryphaenoides myosin yields a singlepredominant band on cellulose acetate electrophoresis and SDS-ureaelectrophoresis in 9% acrylamide gel. The stoichiometric evidenceindicates that Coryphaenoides myosin contains two heavy chains(205,000 mol wt) and two light chains (14,000 mol wt) that areequivalent with respect to net electrostatic charge and molecularweight. Preparations of myosin obtained by direct extractionfrom muscle mince and by dissociation of actomyosin extractedfrom muscle mince also contain 5% of a 47,000 mol wt componentpresumably actin), traces of 34–36,000 mol wt component,and about 5.7% of low molecular weight material (10,000–15,000)that probably represents contaminant protein, although the possibilityof denatured nivosin subunits cannot be excluded.     

First record of the family Embolemidae (Hymenoptera: Chrysidoidea) from Korea

The family Embolemidae Westwood, 1833 is recorded for the first time in Korea, based on a species Embolemus ruddii Westwood. A diagnosis of this species complemented by digital images are provided.