黄山松母树林基地松斑螟的生物学特性及发生规律

松斑螟是危害黄山松梢头和球果的主要害虫。该虫 1年 2代 ,4～ 10月为危害盛期 ,5、6月和 8、9月为危害高峰期。本文主要探讨了该虫的生物学特性和发生规律。     

国槐新害虫——国槐林麦蛾的研究

国槐林麦蛾是 1 998年发现的危害国槐和龙爪槐的新害虫。该虫在山东商河 1年发生 3代 ,幼虫卷缀 2～ 9个叶片或粘连花蕾在其中危害。本文首次报道了该虫幼期的形态特征、危害习性、发生与环境的关系。     

Preliminary studies on leaf beetle, Galeruca daurica on grassland

沙葱萤叶甲Galeruca daurica Joannis是近年来严重危害葱属(AUium)植物建群草场的重要食叶害虫.该虫在内蒙古地区一年发生1代,以卵越冬.本文介绍了该虫生活史、生活习性、发生范围、发生面积、危害症状、生境特征、危害损失,并提出了防治策略.     

美洲斑潜蝇生物学初步观察

美洲斑潜蝇是我国近年来新发生的重要农业害虫,该虫在我省自１９９４年发生以来,发生危害日趋严重,为了给该虫的防治提供科学依据,１９９６～１９９８年我们对该虫的生物学进行了观察,结果整理如下：     

香樟害虫——橄绿瘤丛螟的生物学特性

研究发现嘉兴地区危害香樟树的丛螟科害虫为橄绿瘤丛螟Orthaga olivacea(Warren),对该虫的生物学特性和发生规律做了研究。该虫较为喜欢危害5~10年生香樟树,多头幼虫聚集在一起取食叶片,并缀合受害叶片成鸟巢状虫苞。在嘉兴地区1年发生2代。根据计算幼虫可分为7龄,符合Dyer生长规律。     

江苏金坛地区烟粉虱的发生扩散及寄主适合性分析

系统调查表明,金坛市尧塘花木基地是该地区烟粉虱扩散蔓延的虫源地。该虫4月下旬逐渐从越冬虫源地向外扩散蔓延,首先在葎草[Humulus scandens(Lour)M err]上产卵危害,然后再危害其它植物;距虫源地越近,发生的时间早,虫口密度高,反之,则发生的时间迟,虫口密度低;11月下旬部分种群迁移到温室大棚内越冬。本文还提出了相应的控制措施。     

竹叶涓夜蛾研究初报

记述了竹叶涓夜蛾Rivulabiatomea的寄主范围、形态特征、生物学特性、天敌。该虫在浙江余姚地区每年发生 5代 ,以幼虫越冬。收集并鉴定了寄生性天敌 2 3种。采取预测预报、营林措施、天敌保护和化学治疗等综合防治技术 ,能有效地抑制该虫的危害。     

防治红砂虫的试验

我校厚田生产队部分秧田发生红砂虫,为害很严重。我们对该虫进行了防治试验,现在结果简报如下: 一、发生和危害情况 红砂虫又名红线虫,学名Branchiur spp.发生在近山边土壤粘性较强、含腐植质较多的秧田内。 气温在20℃以上时,此虫最为活跃,其为害是由于它在畦面钻蛀泥土,造成秧田畦面不平而引起烂秧;     

一种新的害虫——大豆根瘤条斑蝇

大豆根瘤条斑蝇Rivellia basilaris(Wiedemann)是在广东增城发现的危害大豆根瘤的一种新害虫。准确鉴定该虫是开展调查、监测与防治等各项工作的基础。本文对该虫成虫的形态特征进行了详细描述,并提供了形态和危害状彩色图片,为该虫准确鉴定提供了依据。     

脐腹小蠹虫的生物学特性

白榆是河南省安阳县主要用材树种,近几年来,白输受脐腹小蠹台虫ScolytusschevyrewiSemenov危害,日趋严重。由于目前国内对该虫的发生发展规律未有报道,给我们的防治工作造成了很大困难。为摸清其发生危害规律,在中国科学院动物研究所昆虫组的指导下,我们对该虫进行了生物学特性研究。1生活史揭3年林间观察,脐腹小蜜虫在安阳县世代重叠,以老熟幼虫为主要越冬虫态,也有不同龄期幼虫、蛹和卵越冬,都能发育完成。3月中旬越冬蛹开始现化,3月下旬至4月上旬出现第一次羽化盛期,以后每隔35～42天完成一代,共6代。10月中下旬是最后一次…     

Pathogenic effect of the trematode Cyclocoeloidea on its hosts

A study of the ecology of Cyclocoeloidea has shown that true pathogenicity of this group of trematodes is much higher than the known one. In addition to the mechanical damage done by marites of cyclocoeloids to the host, migrations of cyclocoeloid larvae in the definitive host's body are a great threat to the latter as well as processes connected with the removal of sexual production by adult worms outside that results usually in a serious damage to the host's organs and tissues.     

The effect of smoking and eating habits on DNA damage in Indian population as measured in the Comet assay

This study was undertaken with the aim of assessing the status of DNA damage in a normal healthy Indian population. The 62 male volunteers in this study belonged to the smoking, non-smoking, vegetarian and non-vegetarian categories, were well educated and aged between 23 and 57 years. The data revealed significant differences in the extent of DNA damage in the smokers versus non-smokers as well as between the vegetarians and non-vegetarians. A significant difference was also observed amongst the different groups of smokers depending on the extent of smoking. An age-dependent effect in DNA damage was also observed. This preliminary study has, for the first time, revealed differences in the extent of DNA damage in the normal Indian population depending on their eating and smoking habits as well as age.     

Effects of DNA damage and short-term spindle disruption on oocyte meiotic maturation

DNA damage has recently been shown to inhibit or delay germinal vesicle breakdown (GVBD) in mouse oocytes, but once meiosis resumes, DNA-damaged oocytes are able to extrude the first polar body. In this study, using porcine oocytes, we showed that DNA damage did not affect GVBD, but inhibited the final stages of maturation, as indicated by failure of polar body emission. Unlike mitotic cells in which chromosome mis-segregation causes DNA double-strand breaks, meiotic mouse oocytes did not show increased DNA damage after disruption of chromosome attachment to spindle microtubules. Nocodazole-treated oocytes did not display increased DNA damage signals that were marked by γH2A.X signal strength, but reformed spindles and underwent maturation, although aneuploidy increased after extended nocodazole treatment. By using the mouse for parthenogenetic activation studies, we showed that early cleavage stage embryos derived from parthenogenetic activation of nocodazole-treated oocytes displayed normal activation rate and normal γH2A.X signal strength, indicating that no additional DNA damage occured. Our results suggest that DNA damage inhibits porcine oocyte maturation, while nocodazole-induced dissociation between chromosomes and microtubules does not lead to increased DNA damage either in mouse meiotic oocytes or in porcine oocytes.     

Stressed out mitochondria: The role of mitochondria in ageing and cancer focussing on strategies and opportunities in human skin

Mitochondrial DNA damage has been used as a successful and unique biomarker of tissue stress. A valuable example of this is sun damage in human skin which leads to ageing and skin cancer. The skin is constantly exposed to the harmful effects of sunlight, such as ultraviolet radiation, which causes it to age with observable characteristic features as well as clinical precancerous lesions and skin cancer. Formation of free radicals by the sun's harmful rays which contribute to oxidative stress has been linked to the induction of deletions and mutations in the mitochondrial DNA. These markers of mitochondrial DNA damage have been proposed to contribute to the mechanisms of ageing in many tissues including skin and are associated with many diseases including cancer. In this article we highlight the role of this important organelle in ageing and cancer with particular emphasis on experimental strategies in the skin.     

RASSF1A suppresses the activated K-Ras-induced oxidative DNA damage

The mutant K-Ras elevates intracellular reactive oxygen species (ROS) levels and leads to oxidative DNA damage, resulting in malignant cell transformation. Ras association domain family 1 isoform A (RASSF1A) is known to play a role as a Ras effector. However, the suppressive effect of RASSF1A on K-RasV12-induced ROS increase and DNA damage has not been identified. Here, we show that RASSF1A blocks K-RasV12-triggered ROS production. RASSF1A expression also inhibits oxidative DNA damage and chromosomal damage. From the results obtained in this study, we suggest that RASSF1A regulates the cellular ROS levels enhanced by the Ras signaling pathway, and that it may function as a tumor suppressor by suppressing DNA damage caused by activated Ras.     

Protective effect of Amphiroa dilatata on ROS induced oxidative damage and MMP expressions in HT1080 cells

Antioxidative and matrix metalloproteinase (MMP) inhibitory effects of methanolic extract from A. dilatata were investigated in HT1080 cells. Treatment with A. dilatata extract suppressed the intensity of electron spin resonance signal on the generation of DPPH radicals in a cell-free system and intracellular reactive oxygen species (ROS) formation by 2′,7′-dichlorofluorescin diacetate (DCFH-DA). Radical simulated oxidation of membrane proteins and lipids were also inhibited by treatment with A. dilatata extract in a concentration-dependent manner. In addition, a protective effect on oxidative damage of purified genomic DNA was observed in the presence of A. dilatata extract. These results revealed that A. dilatata has an excellent scavenging ability on ROS-induced oxidative damage. Moreover, this extract reduced the expression levels of MMP-2 and -9 in gelatin zymography, and RT-PCR analysis without any cytotoxic influence. Therefore, A. dilatata has a promising potential as a valuable source to be used as ingredient in functional foods, related to oxidative damage.     

Studies on oxygen and volume restrictions in cultured cardiac cells I. A model for ischemia and anoxia with a new approach

Summary A novel incubation unit is described that is highly suitable for thorough studies of oxygen deprivation states. Its application with cultured heart cells is experimentally demonstrated. The release of enzymes, taken as a marker for cell damage, has clearly shown that restriction of the volume of extracellular medium combined with oxygen plus glucose deprivation caused greatest cellular damage. It may be considered as an experimental ischemia-like state. Furthermore, the onset of cellular damage followed a time table very much like that occurring in vivo under similar conditions, more so than any other previously described studies. A time lag between the release of cytoplasmic enzymes and lysosomal enzymes and other observations made in the present study suggests a sequential order of events in which the release of cytoplasmic enzymes occurs at a stage of reversible damage due to oxygen deprivation, whereas the release of lysosomal enzymes may point at irrepairable damage. Supported by grants from The Chief Scientist, Ministry of Health, State of Israel; The Ministry of Education and Sciences, State of Niedersachsen (FRG); and The Foundation for Heart Research from Mr. and Mrs. D. Vidal-Madjar, Paris, France. This study was done as partial fulfilment of Vemuri's Ph.D. thesis in biochemistry.     

Damage Function and Economic Threshold for Belonolaimus longicaudatus on Potato

Belonolaimus longicaudatus has long been recognized as a pathogen of potato (Solanum tuberosum). However, a damage function relating expected yield of potato to population densities of B. longicaudatus at planting has not been derived, and the economic threshold for nematicide application is unknown. The objectives of this study were to derive the damage function of B. longicaudatus on potato and to calculate the economic threshold population density. The damage function data for B. longicaudatus on potato were obtained from an ongoing field study to evaluate cropping systems and nematode management practices. Soil samples were collected from experimental field plots, and nematodes were extracted from a 130-cm³ subsample with a centrifugal-flotation method. A damage function was derived by linear regression of potato yield on nematode population density at planting. Based on this derived damage function and published potato prices, the economic threshold for nematicide application was calculated at 2 to 3 B. longicaudatus/130 cm³ of soil, which was near the detection threshold based on methodology used in this study.     

冰雪灾害对森林的影响

冰雪灾害是一种常见的自然灾害,往往对森林造成很大破坏。随着冰在树冠上不断积累,产生的压力逐渐增大,最后超过该部位最大弯曲力矩时林木会受到伤害。受害程度与林分的多种特征,如树种组成和林分密度及林木的多种特征,如胸径、树高、树干尖削度、叶片表面积、树冠对称性、根系、林龄等有密切关系。影响冰雪灾害的外部因素有地形因子和土壤因子,包括海拔、坡度、坡向、坡位和土壤类型、土壤厚度、土壤水分含量。冰雪灾害对林下光照、土壤、凋落物、真菌和森林动物产生影响。冰雪灾害后的林下光照对树种更新、森林动态和恢复具有重要意义。研究冰雪灾害对天然林的影响,长期监测冰雪灾害后的森林动态、林下植物的光环境、森林的养分循环、土壤以及森林动物,特别是土壤微生物的变化,加强森林的防灾管理是今后该领域的研究方向。     

Comparative studies on the role of calcium in triggering subcellular damage in cardiac muscle

Isolated cardiac muscle strips from amphibians and mammals, together with isolated frog hearts, have been used as model systems for studying the action of elevated [Ca2+]i in promoting severe damage. A23187 and caffeine are believed to cause a rise in [Ca2+]i. Elevated [Ca2+]i causes characteristic damage which has been categorized and includes hypercontraction, Z-line damage and myofilament dissolution. The damage closely resembles that described in the isolated mammalian heart and in skeletal muscle preparations when [Ca2+]i is raised dramatically. Damage can therefore be triggered by releasing Ca2+ from intracellular sites, as distinct from increasing Ca2+ entry (as in the Ca2+-paradox). DNP and ruthenium red also cause identical damage and the results suggest that whilst the fall in pHi associated with ischaemia is probably the consequence of Ca2+/2H+ exchange at the mitochondria, coupled with ATP hydrolysis, lowered pHi by mitochondrial action is probably not the only cause of myofilament dissolution. Damage is not prevented by pretreatment with leupeptin, an inhibitor of Ca2+-activated neutral proteases, and it is concluded that the latter are probably not implicated in rapid and dramatic damage. The possible involvement of lysosomal enzymes in damage triggered by high [Ca2+]i is discussed.