The role of lignin as a defence against the spruce bark beetle Dendroctonus micans: effect on larvae and adults

Summary The role of lignin as a physical defence against Dendroctonus micans was investigated in laboratory feeding experiments. The effect of lignin is dose-dependent, reducing larval survival, growth rate, and weight, as well as affecting gallery construction. Adults lay fewer eggs in lignified bark and also tend to construct abnormal galleries. The distribution of lignin in trees suggests a role in defence against bark beetles that feed in the thicker bark on the lower bole.     

支原体菌株低温保存活力稳定性研究

目的研究低温冻存时间及温度对支原体菌种保存稳定性和菌种活力的影响。方法用固体平板计数法计算不同冻存时间、温度下的口腔支原体、肺炎支原体菌落数差异,分析这2个因素对口腔支原体、肺炎支原体菌种活力的影响。结果口腔支原体在生长48 h后达到生长高峰,肺炎支原体生长较为缓慢,在103 h到达生长高峰。口腔支原体在-70℃冻存1个月时,菌落数由10¹² cfu/mL下降至10¹¹ cfu/mL,冻存1个月的菌落数和冻存3个月、12个月的菌落数比较,差异均无统计学意义(P>0.05)。肺炎支原体在-70℃的冻存条件下,菌落数一直处于稳定水平;比较-35℃与-70℃的冻存条件下肺炎支原体的菌落数,差异无统计学意义(P>0.05),口腔支原体在-70℃冻存条件下的菌种活力明显高于-35℃(P<0.05)。结论口腔支原体生长迅速,但对于储存温度的敏感性较高,肺炎支原体相较口腔支原体生长缓慢,停滞期较长,菌株对冻存温度和时间的敏感度较低,稳定性高。菌种冻存温度应选择较低温度,冻存周期在1年内较为稳定。     

舒血宁注射液联合胞磷胆碱钠对脑梗死患者神经功能及血清IGF-1、vWF、HIF-1α水平的影响

目的:研究舒血宁注射液联合胞磷胆碱钠对脑梗死患者神经功能及血清胰岛素样生长因子(IGF-1)、血浆血管性病友因子(v WF)、缺氧诱导因子-1α(HIF-1α)水平的影响。方法:收集2014年3月至2016年3月我院收治的120例脑梗死患者,按抽签法分为对照组和实验组,每组各60例。两组均采用基础治疗,对照组在此基础上采用胞磷胆碱钠治疗,每次2粒,每天3次;实验组在对照组的基础上采用舒血宁注射液治疗,每次5 m L,加入0.9%生理盐水250 m L中混合后进行静脉滴注,每天1次。两组治疗疗程均为2周。对比两组治疗前后神经功能缺损评分(NIHSS)、日常生活能力(ADL),血清IGF-1、v WF、HIF-α水平的变化,不良反应的发生情况及治疗疗效。结果:治疗后,实验组总有效率显著高于对照组[91.66%(55/60) vs. 71.66%(43/60)](P0.05),NIHSS评分显著低于对照组[(7.01±1.23)分vs.(10.52±1.98)分](P0.05),ADL评分显著高于对照组[(68.16±5.62)分vs.(56.20±5.13)分](P0.05);血清IGF-1水平显著高于对照组[(174.29±27.35)IU/mL vs.(152.08±25.29)IU/mL](P0.05),血清v WF、HIF-α水平显著低于对照组[(5.63±1.21)mg/L vs.(11.92±1.35)mg/L,(14.21±3.11)μmol/L vs.(20.16±3.89)μmol/L](P0.05);两组不良反应的发生率比较无显著差异(P0.05)。结论:舒血宁注射液联合胞磷胆碱钠治疗脑梗死的临床疗效显著优于单用胞磷胆碱钠治疗,其可有效改善患者的神经功能,恢复脑组织功能,可能与其效减轻炎症反应及抑制氧化应激反应有关。     

小麦中小GTP结合蛋白基因TaRop2克隆及其表达分析

小GTP结合蛋白属于Rho家族,是植物特有的一类蛋白,在调控植物生长发育、抗逆和抗病过程中发挥着重要的作用。本研究通过筛选非亲和条锈菌小种CYR32侵染诱导的抗条锈病基因Yr5近等基因系(Taichung29*6/Yr5)c DNA文库,分离获得1个Rop家族基因的全长c DNA序列,命名为TaRop2(Triticum aestivum Rop2)。TaRop2包含1个591 bp的开放阅读框,预测编码含197个氨基酸残基的蛋白质,分子量为21.52 k D,理论等电点为9.49。通过在烟草表皮细胞瞬时表达,发现TaRop2分布于细胞核内和细胞膜上。RT-PCR分析结果表明,在高盐处理、非亲和条锈菌小种CYR32和亲和混合白粉菌菌株侵染时,TaRop2基因的表达水平升高,但被干旱、高温、低温和ABA处理抑制。说明TaRop2可能参与小麦防卫和抗逆反应过程。     

依达拉奉联合血栓通对急性脑梗死的疗效及对神经功能缺损和日常生活能力的影响

目的:探讨依达拉奉联合血栓通治疗急性脑梗死(ACI)的临床疗效及对患者神经功能缺损和日常生活能力的影响。方法:将我院2011年1月-2013年1月收治的98例ACI患者按照入院先后顺序随机分为两组,每组各49例,其中对照组在对症治疗基础上加用依达拉奉,而观察组在对照组的基础上加用血栓通,对比两组临床疗效及患者神经功能缺损评分(NIHSS)、日常生活能力(ALD)评分及不良反应发生率。结果:观察组总有效率为91.92%,显著高于对照组的71.43%(P0.05);观察组治疗后NIHSS评分为(10.18±2.21)分,而ALD评分为(57.42±3.66)分,较对照组和治疗前均有显著改善(P0.05);两组不良反应发生率比较差异无统计学意义(P0.05)。结论:依达拉奉联合血栓通治疗ACI疗效显著,可明显改善患者神经功能缺损、提高日常生活能力,具有较好的临床应用价值。     

Circadian variations in the activities of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase in the liver of control and streptozotocin-induced diabetic rats

The aim of this study was to examine: the 24 h variation of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase activities, key enzymes for the maintenance of intracellular NADPH concentration, in rat liver in control and streptozotocin-induced diabetic animals. Adult male rats were fed ad libitum and synchronized on a 12:12 h light-dark cycle (lights on 08:00 h). One group of animals was treated with streptozotocin (STZ, 55 mg/kg, intraperitoneal) to induce experimental diabetes. Eight weeks after STZ injection, the animals were sacrificed at six different times of day—1, 5, 9, 13, 17 and 21 Hours After Lights On (HALO)—and livers were obtained. Enzyme activities were determined spectrophotometrically in triplicate in liver homogenates and expressed as units per mg protein. 6-phosphogluconate dehydrogenase activity was measured by substituting 6-phosphogluconate as substrate. Glucose-6-phosphate dehydrogenase activity was determined by monitoring NADPH production. Treatment, circadian time, and interaction between treatment and circadian time factors were tested by either one or two way analysis of variance (ANOVA). Two-way ANOVA revealed that 6-phosphogluconate dehydrogenase activity significantly depended on both the treatment and time of sacrifice. 6-phosphogluconate dehydrogenase activity was higher in control than diabetic animals; whereas, glucose-6-phosphate dehydrogenase activity did not vary over the 24 h in animals made diabetic by STZ treatment. Circadian variation in the activity of 6-phosphogluconate dehydrogenase was also detected in both the control and STZ treatment groups (one-way ANOVA). Time-dependent variation in glucose-6-phosphate dehydrogenase activity during the 24 h was detected in control but not in diabetic rats. No significant interaction was detected between STZ-treatment and time of sacrifice for both hepatic enzyme activities. These results suggest that the activities of NADPH-generating enzymes exhibit 24 h variation, which is not influenced by diabetes.     

Compatible and incompetent Paxillus involutus isolates for ectomycorrhiza formation in vitro with poplar (Populus x canescens) differ in H2O2 production

Abstract: Isolates of Paxillus involutus (Batsch) Fr. collected from different hosts and environmental conditions were screened for their ability to form ectomycorrhizal symbiosis with hybrid poplar P. × canescens ( = Populus tremula L. × P. alba) in vitro. The ability to form ectomycorrhiza varied between the fungal isolates and was not correlated with the growth rate of the fungi on agar-based medium. The isolate MAJ, which was capable of mycorrhiza synthesis under axenic conditions, and the incompetent isolate NAU were characterized morphologically and anatomically. MAJ formed a typical hyphal mantle and a Hartig net, whereas NAU was not able to penetrate the host cell walls and caused thickenings of the outer cell walls of the host. MAJ, but not NAU, displayed strong H₂O₂ accumulation in the outer hyphal mantle. Increases in H₂O₂ in the outer epidermal walls and adjacent hyphae of the incompetent isolate were moderate. No increases of H₂O₂ in response to the mycobionts were found inside roots. Suggested functions of H₂O₂ production in the outer hyphal mantle of the compatible interaction are: growth regulation of the host's roots, defence against other invading microbes, or increasing plant-innate immunity. The system established here for P. × canescens compatible and incompetent fungal associations will be useful to take advantage of genomic information now available for poplar to study tree-fungal interactions at the molecular and physiological level.     

Inducible defence against a ciliate grazer Pseudomicrothorax dubius,in two strains of Phormidium (cyanobacteria)

Experiments were done with two strain of filamentous, mat-forming Phormidium and their ciliate grazer Pseudomicrothorax dubius, to explain why the ciliates remain hungry in an apparent surplus of food, except for the first 24 hours after feeding. Under grazing pressure, both strains of cyanobacteria showed statistically significant increases in the number of filaments terminating in an empty sheath, compared to the control. Direct observations revealed that the mechanism behind this effect was active withdrawal of the trichomes inside the sheaths when disturbed by grazers. As P. dubius is unable to ingest trichomes with such endings, we conclude that cyanobacteria are not limited to chemical means of defence against grazers but can also defend themselves by means of movement and changes in filament morphology. This is apparently the first report on behavioural defence observed in cyanobacteria.     

Cellular defence mechanism of the clam Tapes semidecussatus against infection by the protozoan Perkinsus sp.

The cellular defence mechanism of the clam Tapes semidecussatus (Mollusca, Bivalvia) against infection by the parasite protozoan Perkinsus sp. (Apicomplexa, Perkinsea) was studied in the gill filaments. The parasites, localized in the connective tissue, induced a cellular reaction involving infiltrated granulocytes. These showed a secretory aspect, with the cytoplasm being filled by membrane-bound granules with internal membranes. The holocrine secretion, which was proteic and slightly glycosylated, by the granulocytes gave rise to the encapsulation of the parasites. After incubation with lectins from Canavalia ensiformis, Triticum vulgaris, Helix pomatia, Glycine max, Arachis hypogaea, Ricinus communis (agglutinin), Ulex europeus I and Limax flavus, a lack of specific and/or main sugars was observed in the plasma membrane of parasite and granulocyte, and in the wall of the former. Furthermore, GalNac1,3GalNac and -d-gal residues were only detected in association with the internal membranes and dense regions of both granules and capsule, respectively. Blood granulocytes were observed at the periphery of the cellular reaction, close to blood vessels, and these appeared to re-differentiate to give the granulocytes of the cellular reaction. The data reported here suggest that this parasite induces the infiltration and re-differentiation of specialized cells in the host mollusc. In addition, a polarized secretion of a specific defence product is described for the first time.