抗逆转录病毒药对孕育期雌鼠心血管影响*

目的: 评价抗逆转录病毒药对孕育期雌性大鼠心血管功能及某些生化指标的影响。方法: SD大鼠9周龄雌鼠19只、10周龄雄鼠6只,9只/10只雌鼠与3只雄鼠合1笼,共2笼,分为正常对照组(CON)、高效抗逆转录病毒治疗组(HARRT)。其中CON组雌性大鼠每天早、晚生理盐水 (10 ml/kg)灌胃,HARRT组雌性大鼠灌等容积抗逆转录病毒药(AZT 31.25 mg/kg +3TC 15.63 mg/kg +LPV/r (41.67/10.42) mg/kg),连续3个月。记录雌性大鼠体重、存活情况;检测超声心动图,多导生理记录仪检测动脉血压、心脏血流动力学参数;相应试剂盒检测血糖、血脂四项、心肌酶及肝酶;Masson染色及透射电镜分别观察心肌胶原纤维和心肌细胞超微结构。结果: CON组雌性大鼠均存活(9/9),HARRT组雌性大鼠存活6只(6/10);与CON组比较,HAART组雌性大鼠体重减少(P＜ 0.01);LVDd、IVST、LVPWT、LAD增加(P＜0.05);动脉舒张压增加(P＜0.05)、LVP +dP/dt_max减少(P＜0.01);TG减少、Glu增加(P＜0.05)、CK减少(P＜0.01)、GOT减少(P＜0.05);心肌组织胶原纤维增多,心肌细胞超微结构异常。结论: 抗逆转录病毒药可导致孕育期雌性大鼠心血管病变。     

中国梭梭属植物历史分布格局及其驱动机制

梭梭属(Haloxylon)植物是藜科的古老孑遗物种, 探究末次间冰期(last interglacial period, LIG)和末次盛冰期(last glacial maximum period, LGM)以来中国梭梭属植物的历史地理分布格局及其驱动机制, 对了解气候变化背景下旱生植物区系的发展与演化具有重要意义。本研究利用梭梭属85个自然分布点数据(60条梭梭(Haloxylon ammodendron)分布记录、25条白梭梭(H. persicum)分布记录)和2套环境因子数据, 整合GIS空间分析和9种物种分布模型, 分析了梭梭属末次间冰期以来的地理分布格局变化及其驱动机制。基于62个梭梭属种群的叶绿体基因测序数据, 利用最小成本路径方法, 模拟了末次间冰期以来梭梭属可能的扩散路径。利用R软件prcomp函数对影响梭梭属分布的环境变量进行主成分分析(principal component analysis, PCA), 评价了环境变量对梭梭属适宜分布的贡献, 并分析了关键变量与分布适宜性的相关性。结果表明: (1)集成模型的模拟精度较单一模型显著提升, 且对白梭梭的模拟精度高于梭梭; (2)末次间冰期以来, 梭梭属植物的分布均经历了显著收缩和冰后期扩张, 末次间冰期至末次盛冰期时期, 在准噶尔盆地、塔里木盆地西部广泛分布的梭梭大面积向西退缩至避难所(准噶尔盆地西北缘和塔里木盆地西北缘); 白梭梭从准噶尔盆地、塔里木盆地西端向南退缩至避难所(准噶尔盆地南缘); 末次盛冰期至今, 梭梭向东沿甘肃北部扩张直至内蒙古西部阿拉善荒漠, 白梭梭向东北方向小范围扩张, 占据了准噶尔盆地西部和南缘; (3)末次间冰期以来的气候波动对梭梭属植物的分布存在较大限制, 降水因子主导了梭梭属适宜分布面积的变化, 温度因子影响了梭梭属分布适宜性的高低。     

阔叶红松林不同林层和生长阶段树木生长对采伐强度的响应

采伐是调整林分结构的重要手段。不同林层的树木对采伐强度有着不同的响应方式。但以往考察采伐对树木生长的影响时多采用定性或简单定量的方法(如按树高等距)划分森林的垂直层次, 这就忽略了同一林层内不同树种间和不同发育阶段树木生长的差异。该研究在吉林蛟河天然阔叶红松(Pinus koraiensis)林内建立轻度(胸高断面积采伐强度17.3%)、中度(34.7%)、重度(51.9%)采伐以及对照(不采伐)样地, 跟踪调查采伐后自然恢复2、4、7年保留木的生长动态。根据不同树种每一个体所处的林层位置和生长发育阶段, 将保留木划分为3个组别: 林冠层树种的成熟个体(I)、林冠层树种的未成熟个体(II)以及林下层树种的全部个体(III), 比较不同恢复时期各组别树木的生长对于采伐强度的响应差异。结果表明, 第II组树木的平均胸径相对生长速率(0.033 cm·cm^-1·a^-1)显著高于第I (0.016 cm·cm^-1·a^-1)和III组(0.018 cm·cm^-1·a^-1)。总体来看, 采伐促进了大多数林冠层优势树种(第I、II组)的生长, 尤其是第II组树木的相对生长速率随采伐强度的增加而增加, 但第I组树木的相对生长速率只在重度采伐样地显著高于对照样地。然而林冠层少见种的生长速率并未受到采伐活动的显著影响。值得注意的是, 第I和II组树木生长对于采伐的响应都存在一定的时间滞后, 伐后短期内(2年)采伐样地与对照样地的生长速率没有显著差异, 而采伐对树木生长的促进效果在伐后2-4年才开始出现, 并在随后的监测期内持续存在。各组别树木的相对生长速率均随初始胸径的增大而降低, 且这种负相关关系的斜率随采伐强度增加逐渐增大, 表明随着采伐强度增加, 较小的树木个体从减弱的竞争中获益更多, 呈现出更加明显的生长释放现象。     

Characteristics of sugarcane white leaf phytoplasma transmission by the leafhopper Matsumuratettix hiroglyphicus

The leafhopper Matsumuratettix hiroglyphicus (Matsumura) (Hemiptera: Cicadellidae) is the most important vector of sugarcane white leaf (SCWL) phytoplasma that significantly affects the sugarcane crop in Asia. Here, we aimed to study the characteristics of SCWL phytoplasma transmission by M. hiroglyphicus. To this end, the stylet penetration activities performed during the acquisition access period (AAP) and inoculation access period (IAP) were investigated by the direct current electrical penetration graph technique and confirmed by quantitative polymerase chain reaction (qPCR). Additionally, the latent period (LP) of SCWL phytoplasma in the vector was determined by qPCR and localised by fluorescent in situ hybridisation. The results indicated that the acquisition of SCWL phytoplasma occurred during phloem ingestion (waveform D), whereas its inoculation was associated with salivation into the phloem sieve element (waveform C). The minimum AAP was 15 min and the minimum duration of phloem ingestion was 2.35 min. The minimum LP of SCWL phytoplasma in the vector was at least 14 days; then, SCWL phytoplasma moved to the salivary glands of the insect, enabling the transmission of the pathogen to the host plants. The minimum IAP for a successful transmission of SCWL phytoplasma to the host plants was 11–12 min, with a minimum duration of salivation into phloem of 1.35 min. The female vectors had higher SCWL phytoplasma copy numbers than the male vectors, and displayed faster AAP, IAP, and LP. Overall, our findings provide important information related to the feeding behaviour of M. hiroglyphicus and its effect on the transmission of SCWL phytoplasma.     

我国丹顶鹤栖息地选择研究进展

丹顶鹤(Grus japonensis)是我国Ⅰ级重点保护野生动物,被世界自然保护联盟列为濒危物种。本研究通过搜集和整理2000至2017年丹顶鹤栖息地选择和生境适宜性相关文献,分析了丹顶鹤在繁殖期、迁徙期、越冬期的栖息地选择,发现丹顶鹤在这三个时期的最偏好生境均为芦苇沼泽或芦苇滩,回避人为干扰较为严重的居民点、道路、盐田等生境。通过梳理丹顶鹤繁殖地、中途停歇地、越冬地的栖息地变化及其原因,发现丹顶鹤栖息地变化是自然因素和人为因素共同驱动的结果,以人为因素为主。本研究希望为科学评价栖息地变化对丹顶鹤野生种群的影响、针对性地开展栖息地保护管理工作、促进丹顶鹤野生种群健康可持续发展提供依据。     

Transcriptome analysis of the endometrium from Chinese Erhualian sows that differ in calcium ion concentration and litter size

Embryonic survival rate, an important factor in the fecundity of sows, is affected by endometrium‐secreting histotroph. A higher concentration of calcium ion has been observed in the uterus of highly prolific Erhualian sows (EH) compared with those of less prolific (EL) sows. This suggests that EH sows have better establishment and maintenance of pregnancies, thus increasing embryonic survival rate during the peri‐implantation period. To understand the mechanisms of how the endometrium‐secreting histotroph affects embryonic survival rate during the Erhualian peri‐implantation period, the expression patterns of endometrial mRNA in the EH and EL sows on day 12 of gestation were analyzed using RNA sequencing technology. A total of 164 differentially expressed genes (DEGs) were identified (P_adj < 0.05, |log₂(FC)| ≥ 1), including 46 upregulated and 118 downregulated genes in EH compared to EL. Gene Ontology enrichment indicated that a subset of DEGs was involved in calcium ion binding and cell adhesion. Solute carrier family 8 member A3 and solute carrier family 24 member 4, identified as upregulated genes (P_adj < 0.05) in EH, were considered key candidate genes expressed in the endometrium affecting embryonic survival rate during the peri‐implantation period. The results improve understanding of the genetic mechanism underlying the variation in litter size of Erhualian pigs during the peri‐implantation period.     

Effects of various LED light spectra on circadian rhythm during starvation in the olive flounder (Paralichthys olivaceus)

In aquaculture, feeding is essential for the maintenance of metabolic processes and homoeostasis of fish. However, fasting acts as a stressor. In this study, we investigated the effect of circadian rhythm under various LED wavelengths [blue (460 nm), green (520 nm) and red (630 nm)] and two light intensities (0.3 and 0.6 W m^?2) over a 9-days period in the olive flounder (Paralichthys olivaceus). We analysed clock genes like period 2 (Per 2) and cryptochrome 1 (Cry 1), and serotonin and arylalkylamine-N-acetyltransferase 2 (AANAT 2), which control circadian rhythms. Per 2, Cry 1, serotonin and AANAT 2 were significantly decreased during the starvation period compared to the normal feeding group. Nevertheless, their levels increased in the groups exposed to green- and blue LED light during the experimental period. These results confirmed that green and blue wavelengths are effective in maintaining the circadian rhythm in olive flounder.     

Assessing the performance of pea and lentil at different seeding densities as trap crops for the management of wireworms in spring wheat

Wireworms, the larvae of click beetles (Elateridae), are difficult to manage due to their habitats and behaviour. Wireworms pose a major threat to the wheat crop in the north‐western USA. Seed treatment with neonicotinoids, biological control management and some cultural controls are recommended to manage these pests. Trap cropping is an emerging way to manage wireworms. In strawberry and potato crops, trap cropping has been found effective at attracting wireworms away from the principal crop. An earlier study in the Golden Triangle area of Montana found that pea and lentil could be effective trap crops for managing wireworms in spring wheat. In the present study, experiments were conducted at two locations. The effectiveness of peas and lentils as trap crops with wheat at different seeding densities was assessed [pea at 0, 4, 8, 16 seeds/sq.ft. or 0, 43, 86, 172 seeds/sq.m.; lentil at 0, 6, 12, 18 OR 0, 65, 130, 194 seeds/sq.m.; both with wheat at 0, 11, 22, or 28 seeds/sq.ft. or 0, 120, 230, 300 seeds/sq.m.] in a randomized design where all three crops were intercropped. Both trap crops were found to be effective in protecting wheat at standard seeding rates of 8 seeds/sq.ft. for pea and 12 seeds/sq.ft. for lentils. At these seeding rates, higher numbers of wireworms were found to be attracted to the trap crop, resulting in higher yield (7%–10%) of the associated spring wheat plant stands at 22 seeds/sq.ft. To develop an effective trap crop strategy, the pea–wheat and lentil–wheat spatial patterns that are possible need to be assessed in further field trials. Proper design and evaluation of the cost–benefit ratio of pea and lentil as trap crops are likely to produce good results for wheat crops in Montana.