Effects of in vivo exposure to DEET on blood feeding behavior and fecundity in Anopheles quadrimaculatus (Diptera: Culicidae)

This study determined the effects of contact with DEET on guinea pig skin on mortality, probing time, blood feeding rate, engorgement time, and fecundity responses in female Anopheles quadrimaculatus Say. Exposure, in this manner, to 10% DEET (in ethanol) for 5 min, resulted in 98% mortality in mosquitoes after 24h. The median probing time (PT(50)) required by females, when exposed to 0.1%, 1.0%, and 10% DEET, was significantly (P<0.0001) longer (12.5, 12.1, and 19.1s, respectively) than the 6.8s required by females to probe ethanol-treated skin (control). Similarly, mean blood feeding rates in populations of females exposed to 1.0% DEET for < or = 5 min (14.4%) was 6x lower (P<0.001) (85.5%) than in females exposed to ethanol-treated skin, whereas the mean engorgement time on skin treated with 1.0% DEET (66.3s) was significantly shorter (P<0.0001) than for females feeding on the control guinea pigs (105.9s). The mean number of mature o?cytes per female (fecundity) in treatment (1.0% DEET) and control mosquitoes was not significantly different. The responses to DEET observed in this study suggest that repeated exposure of female A. quadrimaculatus populations to this repellent, in laboratory bioassays, could result in confounding of toxicant and repellent effects and inaccurate estimates of DEET repellency.     

Protein C is an autocrine growth factor for human skin keratinocytes

The protein C (PC) pathway plays an important role in coagulation and inflammation. Many components of the PC pathway have been identified in epidermal keratinocytes, including endothelial protein C receptor (EPCR), which is the specific receptor for PC/activated PC (APC), but the core member of this pathway, PC, and its function in keratinocytes has not been defined. In this study, we reveal that PC is strongly expressed by human keratinocytes at both gene and protein levels. When endogenous PC was blocked by siRNA the proliferation of keratinocytes was significantly decreased. This inhibitory effect was restored by the addition of recombinant APC. PC siRNA treatment also increased cell apoptosis by 3-fold and inhibited cell migration by more than 20%. When keratinocytes were pretreated with RCR252, an EPCR-blocking antibody, or PD153035, an epidermal growth factor receptor (EGFR) inhibitor, cell proliferation was hindered by more than 30%. These inhibitors also completely abolished recombinant APC (10 mug/ml)-stimulated proliferation. Blocking PC expression or inhibiting its binding to EPCR/EGFR decreased the phosphorylation of ERK1/2 but increased p38 activation. Furthermore, inhibition of ERK decreased cell proliferation by approximately 30% and completely abolished the stimulatory effect of APC on proliferation. Taken together, these results indicate that keratinocyte-derived PC promotes cell survival, growth, and migration in an autocrine manner via EPCR, EGFR, and activation of ERK1/2. Our results highlight a novel role for the PC pathway in normal skin physiology and wound healing.     

Development of Oryza rufipogon and O. sativa Introgression Lines and Assessment for Yield-related Quantitative Trait Loci

Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research. In this study, an advanced backcross and consecutive selfing strategy was used to develop introgression lines （ILs）, which derived from an accession of Oryza rufipogon Griff. collected from Yuanjiang County, Yunnan Province of China, as the donor, and an elite indica cultivar Teqing （O. sativa L.）, as the recipient. Introgression segments from O. rufipogon were screened using 179 polymorphic simple sequence repeats （SSR） markers in the genome of each IL. Introgressed segments carried by the introgression lines population contained 120 ILs covering the whole O. rufipogon genome. The mean number of homozygous O. rufipogon segments per introgression line was about 3.88. The average length of introgressed segments was approximate 25.5 cM, and about 20.8% of these segments had sizes less than 10 cM. The genome of each IL harbored the chromosomal fragments of O. rufipogon ranging from 0.54% to 23.7%, with an overall average of 5.79%. At each locus, the ratio of substitution of O. rufipogon alleles had a range of 1.67-9.33, with an average of 5.50. A wide range of alterations in morphological and yield-related traits were also found in the introgression lines population. Using single-point analysis, a total of 37 putative QTLs for yield and yield components were detected at two sites with 7%-20% explaining the phenotypic variance. Nineteen QTLs （51.4%） were detected at both sites, and the alleles from O. rufipogon at fifteen loci （40.5%） improved the yield and yield components in the Teqing background. These O. rufipogon-O, sativa introgression lines will serve as genetic materials for identifying and using favorable genes from common wild rice.     

Changes of Photosystem Ⅱ Electron Transport in the Chlorophyll-deficient Oilseed Rape Mutant Studied by Chlorophyll Fluorescence and Thermoluminescence

The photosystem Ⅱ (PSII) complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has de creased the amount of light-harvesting complexes with an increased amount of some core polypeptides of PSII,including CP43 and CP47. By means of chlorophyll fluorescence and thermoluminescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type.In the chlorophyll b-deficient mutant, the decay of the primary electron acceptor quinones (QA-) reoxidation was decreased, measured by the fluorescence. Furthermore, the thermolumlnescence studies in the chlorophyll b deficient mutant showed that the B band (S2/S3QB-) decreased slightly and shifted up towards higher temperatures.In the presence of dichlorophenyl-dimethylurea, which is inhibited in the electron flow to the second electron acceptor quinines (QB) at the PSII acceptor side, the maximum of the Q band (S2QA-) was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyll b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA- via forward electron flow and slower reduction of the oxidation S states.     

Changes of Photosystem Ⅱ Electron Transport in the ChlorophyⅡ-deficient Oilseed Rape Mutant Studied by ChlorophyⅡ Fluorescence and Thermoluminescence

The photosystem Ⅱ （PSII） complex of photosynthetic membranes comprises a number of chlorophyll-binding proteins that are important to the electron flow. Here we report that the chlorophyll b-deficient mutant has decreased the amount of light-harvesting complexes with an increased amount of some core polypeptldes of PSII, including CP43 and CP47. By means of chlorophyll fluorescence and thermolumlnescence, we found that the ratio of Fv/Fm, qP and electron transport rate in the chlorophyll b-deficient mutant was higher compared to the wild type. In the chlorophyll lPdeflclent mutant, the decay of the primary electron acceptor quinones （QA-） reoxidation was decreased, measured by the fluorescence. Furthermore, the thermoluminescence studies in the chlorophyll bdeficient mutant showed that the B band （S2/S3QB-） decreased slightly and shifted up towards higher temperatures. In the presence of dlchlorophenyl-dlmethylurea, which is inhibited in the electron flow to the second electron acceptor quinines （QB） at the PSll acceptor side, the maximum of the Q band （S2QA-） was decreased slightly and shifted down to lower temperatures, compared to the wild type. Thus, the electron flow within PSll of the chlorophyⅡ b-deficient mutant was down-regulated and characterized by faster oxidation of the primary electron acceptor quinine QA-via forward electron flow and slower reduction of the oxidation S states.     

Cloning and biological activity of an anti-tumor peptide of Tumstatin

To obtain an anti-tumor peptide of Tumstatin and detect its biological activity, the nucleotide sequence encoding 185–203 amino acids (19peptide) of Tumstatin was synthesized and inserted into the fusion protein vector pTYB2. After identification by sequencing and restriction endonucleases, the recombined vector was transformed into BL-21 (DE3) E. coli competent cells. Transformed E. coli BL-21 (DE3) were induced by isopropyl-β-thiogalactopyranoside (IPTG), and then expressed. By 1,4-dithiothreitol (DTT) reduction, the soluble 19peptide was obtained from a chitin affinity chromatograph. The biological activity of 19peptide was determined by 3-[4,5-dimethylthiazol-2-y1]-2,5-diphenytetrazolium bromide (MTT) assay, cell growth curve, the effect of the ascitic fluid transfevent H22 hepatoma on mice and via histopathological slices. The purified 19peptide directly inhibited proliferation and migration of murine B16 melanoma cells, SMMC-7721hepatoma carcinoma cells and human umbilical vein endothelial cells (HUVEC). The tumor inhibition rate of mice ascitic fluid transfevent H22 hepatoma was 48.46%. Histopathological slices showed that it could promote tumor tissue necrosis and decrease the density of blood vessels. With higher anti-tumor activity, 19peptide has the potential to become a novel, potent anti-tumor agent. Translated from Chinese Journal of Biochemistry and Molecular Biology, 2005, 21(3): 322–328 [译自: 中国生物化学与分子生物学学报]     

太子参花药发育及精细胞分离

太子参花药壁发育为基本型,腺质绒毡层。小孢子母细胞减数分裂为同时型,小孢子四分体为四面体型,成熟花粉具两个精细胞,为3胞花粉。在花粉表面具散孔,孔数22—30个,均匀分布于花粉粒表面上。花粉在10％甘露醇或15％蔗糖溶液中可直接爆破,精细胞易被释放并散开,通过显微操作仪可收集到一定数目的精细胞。FDA染色荧光显示释放出来的精细胞活力可维持25—50min。花粉在舍O．03％CaCl2、0．01％H3803、0．01％KH2P04和20％PEG、pH5．8的培养液中2—5min即萌发花粉管．花粉管生长2h可达815μm。一般花粉管伸长500—600μm时,一对精细胞才进入花粉管。DAPI染色后荧光观察．可观察到精细胞和营养细胞核在花粉管中的移动状况。爆破花粉管后可释放出一对精细胞。     

The formation of improved tetraploid population of red crucian carp × common carp hybrids by androgenesis

Bisexual fertile diploid androgenetic individuals (A0) (2n=100) were formed by androgenesis. In this way, the diploid spermatozoa from male allotetraploid hybrids (AT) (4n=200) of red crucian carp (Carassius auratus red var.) (♀) × common carp (Cyprinus carpio L.) (♂) were used to fertilize the UV-treated hap- loid eggs of goldfish (Carassius auratus), and living androgenetic diploid fish were developed. The A0 became sexually mature at the age of 2 years, and they fertilized with each other to form their offspring (A1). In this study, we observed the chromosomal number, gonadal structure and appearance of A1 fish. The results are as follows: (1) In A1, there were 85% tetraploids (A1-4n), 10% triploids (A1-3n) and 5% diploids (A1-2n), suggesting that diploid A0 could produce diploid gametes. It was concluded that the formation of diploid gametes generated from diploid A0 was probably related to the mechanism of pre-meiotic endoreduplication. (2) Among A1, only A1-4n possessed normal ovaries and testes. The mature males of A1-4n produced white semen. Under the electron microscope, the head of diploid sperm generated by A1-4n was bigger than that of haploid sperm generated by red crucian carp. In the testes of the A1-4n, there were many mature normal spermatozoa with a head bearing plasma mem- brane and a tail having the typical structure of "9 2" microtubules. Between the head and the tail, there were some mitochondria. The ovaries of A1-4n developed well and mainly contained II, III and IV-stage oocytes. The IV-stage oocytes were surrounded by inner and outer follicular cells. The micropyle was observed on the oolemma of follicular cells. There were abundant yolks and plenty of endoplasmic reticulum in the cytoplasm of IV-stage oocytes. Because A1-2n and A1-3n were distant crossing diploid hybrids and triploid hybrids respectively, they possessed abnormal gonads, and no mature semen and eggs were observed. (3) Compared with allotetraploids, the A1-4n fish not only had advantages such as fast growth rate and strong resistibility but also showed some new good performances such as high ratio of body width to body length, smaller heads and shorter tails. These results indicated that an- drogenesis could produce bisexual fertile tetraploids and improve the shape of allotetraploid hybrids as well, which will be of great significance in both the cell genetics research and fish breeding.