Solid-phase microextraction and cuticular hydrocarbon differences related to reproductive activity in juniper bark borer Semanotus bifasciatus Motschulsky

Cuticular hydrocarbons of Cerambycidae species can function as signals for sex recognition. Little is known about the copulatory signals of the juniper bark borer Semanotus bifasciatus, a major economic threat to Platycladus orientalis Franco in China. Here, we investigated the cuticular hydrocarbons of both sexes of S. bifasciatus to determine the chemically mediated mating signals using the solid-phase microextraction (SPME) technique with carbowax/divinylbenzene fibers (CAR/DVB) and then analyzed by coupled gas chromatography-mass spectrometry (GC-MS). A series of aliphatic saturated straight-chain n-alkanes (n-C₂₃ to n-C₂₈), internally branched monomethylalkanes at carbons 3, 11, or 13, and dimethylalkanes were identified, which showed no qualitative differences in either sex and were similar in the samples with SPME fiber extraction and those with hexane extraction. The bioassay showed that 11-methylpentacosane (11-MeC₂₅), 11-methylhexacosane (11-MeC₂₆), and 11-methylheptacosane (11-MeC₂₇) have sex-specific recognition functions that triggered more mating attempts at a female-specific ratio of 100:4:60 than at a male-specific ratio of 100:85:50. In addition, the female-specific ratio of 11-methylalkanes can elicit about 70% of male mating attempts within about 60 s, whereas live females elicit about 98% of male mating attempts within 25 s. The discrepancy in the initiation of mating attempts by synthetic mixtures and live females suggests that the methyl isomers 3-MeC₂₅, 3-MeC₂₇, and/or 11,15-diMeC₂₇ may also be involved in the mating behavior of S. bifasciatus. These results suggest that 11-MeC₂₅, 11-MeC₂₆, and 11-MeC₂₇ constitute the contact sex pheromone of S. bifasciatus, with the presence or absence of 11-MeC₂₆ in particular playing an important role in mate recognition by males.     

Effect of cadmium intoxication on glucose utilization in energy metabolism of muscles

The influence of cadmium intoxication on carbohydrate metabolism in skeletal muscles and liver of the male Wistar rats has been studied. Cadmium was administered as cadmium acetate in a dose of 0.3 mg Cd2+/kg body weight for three months. At the same time the control rats were injected with 0.9% NaCl. The animals were decapitated and samples of their skeletal muscles: the soleus muscle (composed mainly of red slow twitch fibers; ST) the gastrocnemius muscle containing two types of fibers (white fast twitch fibers FTb and red fast twitch fibers, FTa) and the liver were dissected out. In the samples of muscles, liver and serum contents of glycogen, glucose, pyruvate and lactate, as well as activities of hexokinase, pyruvate kinase and lactate dehydrogenase were measured. Intoxication of rats with cadmium for three months resulted in a reduction of glycolytic enzymes in the serum, ST and FTa muscle fibers and in the liver but did not change the activities of glycolytic enzymes in the FTb muscle fibers. The data obtained for the concentrations of glycogen in the liver and skeletal muscles suggest different mechanisms of cadmium influence on glycogen utilization in these organs.     

Screening and analysis of differentially expressed genes from an alien addition line of wheat Thinopyrum intermedium induced by barley yellow dwarf virus infection.

The alien addition line TAI-27 contains a pair of chromosomes of Thinopyrum intermedium that carry resistance against barley yellow dwarf virus (BYDV). A subtractive library was constructed using the leaves of TAI-27, which were infected by Schizaphis graminum carrying the GAV strain of BYDV, and the control at the three-leaf stage. Nine differentially expressed genes were identified from 100 randomly picked clones and sequenced. Two of the nine clones were highly homologous with known genes. Of the remaining seven cDNA clones, five clones matched with known expressed sequence tag (EST) sequences from wheat and (or) barley whereas the other two clones were unknown. Five of the nine differentially expressed sequences (WTJ9, WTJ11, WTJ15, WTJ19, and WTJ32) were highly homologous (identities >94%) with ESTs from wheat or barley challenged with pathogens. These five sequences and another one (WTJ18) were also highly homologous (identities >86%) with abiotic stress induced ESTs in wheat or barley. Reverse Northern hybridization showed that seven of the nine differentially expressed cDNA sequences hybridized with cDNA of T. intermedium infected by BYDV. Three of these also hybridized with cDNA of line 3B-2 (a parent of TAI-27) infected by BYDV. The alien chromosome in TAI-27 was microdissected. The second round linker adaptor mediated PCR products of the alien chromosomal DNA were labeled with digoxygenin and used as the probe to hybridize with the nine differentially expressed genes. The analysis showed that seven differentially expressed genes were homologous with the alien chromosome of TAI-27. These seven differentially expressed sequences could be used as ESTs of the alien chromosome of TAI-27. This research laid the foundation for screening and cloning of new specific functional genes conferring resistance to BYDV and probably other pathogens.     

玉米根微粒体ABA结合蛋白的性质及逆境胁迫的影响

以玉米根微粒体为材料进行的微量放射配体结合（ＭＲＬＢ）实验表明玉米根微粒体膜上存在着ＡＢＡ结合位点,ＡＢＡ与ＡＢＡ结合蛋白（ＡＢＡ－ＢＰ）结合的最适ｐＨ为６．５,结合反应对温度（０℃和２５℃）不太敏感,ＡＢＡ与ＡＢＡ－ＢＰ的结合反应是一个动态平衡过程,５ｍｉｎ即可达最大结合（Ｂｍａｘ）的５０％,３０ｍｉｎ达到最大结合,１ｈ内基本保持不变。胰蛋白酶处理表明此结合位点为蛋白质,冻融实验则表明此蛋白与ＡＢＡ的结合不仅要求其自身具有特定构象而且需要有一定的膜脂环境,ＤＴＴ处理实验结果显示ＡＢＡ－ＢＰ中可能存在着二硫键。逆境处理可以提高玉米根微粒体膜对ＡＢＡ的结合活性,盐胁迫、渗透胁迫、干旱胁迫和热冲激处理分别使结合活性上升３４．９％、１７．８％、２３．１％和１３．３％。     

肿瘤坏死因子α对白血病细胞作用的^31P核磁共振研究

木文用３１Ｐ核磁共振（ＮＭＥ）观察了人淋巴瘤白血病细胞系Ｍｏｌｔ－４和人早幼粒白血病细胞系ＨＬ－６０的细胞代谢。Ｍｏｌｔ－４和ＨＬ－６０细胞系的３１Ｐ谱主要由磷酸单酯、无机磷（Ｐｉ）、双磷酸双酯、ＡＴＰ的共振峰组成。３１Ｐ谱显示Ｍｏｌｔ－４细胞在受肿瘤坏死因子α（ＴＮＦ－α）作用后,ＡＴＰ／Ｐｉ比值降低。ＨＬ－６０细胞在受ＴＮＦ－α作用后,ＡＴＰ减少。３１Ｐ－ＮＭＲ提供了一种非损伤性研究细胞代谢的重要方法。     

一例智力低下患者7q~ 标记染色体的来源鉴定

以人类染色体显微切割、PCR技术构建的现有人类染色体特异性和染色体区带特异性探针池作为绘画探针,采用正向染色体绘画技术,结合染色体筛查方法,查明了一例7q~ 标记染色体患者的染色体附加片段来源于3q26→3qter。确定该患者的核型为46,XX,-7, der(7)t(7;3)(7pter→7q32::3q26→3qter)。应用这个策略,能够快速有效地鉴定标记染色体的来源。