A comparative study of Echinococcus granulosus from human and animal hosts in Kenya using isoelectric focusing and isoenzyme analysis

Macpherson C. N. L. and Mcmanus D. P. 1982). A comparative study of Echinococcus granulosus from human and animal hosts in Kenya using isoelectric focusing and isoenzyme analysis. International Journal for Parasitology12: 515–521. The soluble enzyme extracts from protoscoleces obtained from hydatid cysts of human, camel, cattle, sheep and goat origin were compared on the basis of their isoenzyme patterns for GPI and PGM using isoelectric focusing. Consistent GPI and PGM isoenzyme patterns were obtained for larvae of human, camel and sheep material. Cattle material varied occasionally in having an additional cathodic band in some of the GPI patterns. Two distinct isoenzyme patterns were evident in the goat material for both enzymes. The more common goat patterns were similar to those of human, cattle and sheep (Kenya, U.K. and Argentina) material, which were similar to each other. The rare goat patterns were similar to those obtained for camel material. Cyst location in the various intermediate hosts had no effect on the zymograms obtained. Additionally, no alteration in the major banding patterns was observed between the larvae and homologous adults produced by experimental infections. Of 26 naturally infected dogs, 19 produced adult GPI zymograms resembling human/ sheep/goat (common form) experimental infection patterns, three were similar to experimental cattle infections and four had camel/goat (rare form) patterns.     

以大蜡螟幼虫为模型研究伏立康唑抗茄病镰刀菌效果

目的构建大蜡螟幼虫动物茄病镰刀菌感染模型并观察伏立康唑治疗效果。方法选用临床分离获得茄病镰刀菌1株,实验所用孢子悬液浓度梯度为1×10⁵~1×10⁸CFU/mL,根据死亡率筛选出最佳感染浓度,并以此浓度感染大蜡螟幼虫,用伏立康唑(1.5 mg/kg)治疗;同时设置未处理组和生理盐水对照组,实验过程中收集大蜡螟幼虫尸体做病理检测并记录5 d内死亡情况,每24 h记录1次。通过感染后病理组织切片和大蜡螟幼虫生存率两个方面进行评价。结果大蜡螟幼虫在1×10⁷CFU/mL茄病镰刀菌感染后,5 d死亡率达100%,1×10⁷CFU/mL为本次实验组最佳感染浓度;大蜡螟幼虫感染第2 d死亡虫体病理检测发现大量茄病镰刀菌菌丝和孢子,经伏立康唑治疗后,单个幼虫体内菌体减少,菌体内菌丝减少;大蜡螟幼虫生存曲线显示伏立康唑治疗组较单茄病镰刀菌感染组生存率显著增高(P<0.05)。结论大蜡螟幼虫能够作为茄病镰刀菌体内感染的动物模型,并可用于观察药物治疗效果。     

The impact of mitochondrial tRNA mutations on the amount of ATP synthase differs in the brain compared to other tissues

The impact of point mutations in mitochondrial tRNA genes on the amount and stability of respiratory chain complexes and ATP synthase (OXPHOS) has been broadly characterized in cultured skin fibroblasts, skeletal muscle samples, and mitochondrial cybrids. However, less is known about how these mutations affect other tissues, especially the brain. We have compared OXPHOS protein deficiency patterns in skeletal muscle mitochondria of patients with Leigh (8363G>A), MERRF (8344A>G), and MELAS (3243A>G) syndromes. Both mutations that affect mt-tRNA(Lys) (8363G>A, 8344A>G) resulted in severe combined deficiency of complexes I and IV, compared to an isolated severe defect of complex I in the 3243A>G sample (mt-tRNA(LeuUUR). Furthermore, we compared obtained patterns with those found in the heart, frontal cortex, and liver of 8363G>A and 3243A>G patients. In the frontal cortex mitochondria of both patients, the patterns of OXPHOS deficiencies differed substantially from those observed in other tissues, and this difference was particularly striking for ATP synthase. Surprisingly, in the frontal cortex of the 3243A>G patient, whose ATP synthase level was below the detection limit, the assembly of complex IV, as inferred from 2D-PAGE immunoblotting, appeared to be hindered by some factor other than the availability of mtDNA-encoded subunits.     

Spatial Distribution,Food and Activity of Gomphus pulchellus SELYS 1840 (Insecta; Odonata; Gomphidae) from a Still Water Habitat

Distribution patterns of Gomphus pulchellus larvae in different sediments with different density of prey organisms were studied in the field in a small gravel pit lake in the south of Germany. Larval burrowing behaviour at different temperatures as well as food preference, consumption rates and activity were studied in laboratory experiments. In the study lake G. pulchellus larvae lived exclusively in places where macrophytes were present and in fine sediments (mean grain size <3 mm) with detritus cover. There was a significant positive correlation between larval density and density of food organisms suggesting that abundance of food is one of the determinants of larval distribution. In late autumn larvae migrated to deeper places probably to survive the winter. Low temperatures simulated in laboratory experiments did not induce larvae to burrow deeper. Larvae were always found in a sediment depth of 0.59–0.74 cm. Experiments with mixed prey showed that G. pulchellus larvae preferred tubificid worms and chironomid larvae over gammarids and ephemerid larvae. However, chironomid larvae which stayed in their tubes had a higher survival rate than those outside of tubes. Single-prey experiments showed that G. pulchellus larvae can prey not only on benthic species but also on Daphnia from the open water. Functional-response experiments showed that one G. pulchellus larva consumes a maximum of 2 to 3 tubificid worms or chironomid larvae per day, which corresponds to a maximum biomass (freshweight) of 5 to 30 mg per day. Video recordings of activity showed that G. pulchellus larvae cover long distances of up to 52 m per night on the substrate surface and that activity on the substrate surface started after midnight and ceased before sunrise. Consumption of Zooplankton prey and high activity above the substrate is interpreted as an adaptation of G. pulchellus larvae to the life in still water habitats.     

荒漠拟步甲科鳖甲族三种幼虫头壳色素区的观察

荒漠拟步甲科鳖甲族昆虫的幼虫具有相似的圆柱状体形,从形态上不易区别。以往对荒漠拟步甲幼虫的形态研究注重于上唇和足等部位的刚毛和小刺的特征,少有对头壳颜色的记载。通过在体视显微镜下观察室内饲养的鳖甲族昆虫(鞘翅目:拟步甲科)小胸鳖甲Microdera punctipennis Kaszab、光滑鳖甲Anatolica polita borealis Kaszab和细颈露颚甲Colposcelis microderoides microderoides Reitter的大龄幼虫,发现它们的头壳色素区呈现出不同的形状和大小,可方便地用于区分这3种幼虫。同时,测量结果显示幼虫头壳宽与前胸背板宽之比在这3种幼虫有显著差异。     

Patterns of mobilization of calcium,magnesium, and phosphorus by embryonic yellow-headed blackbirds(Xanthocephalus xanthocephalus)

Summary Embryonic blackbirds(Xanthocephalus xanthocephalus) obtain most of their calcium from the eggshell (85 90%), but all of their phosphorus comes from reserves in the yolk (80–85%) and albumen (15–20%). Approximately equal amounts of magnesium are supplied by the eggshell, the yolk, and the albumen. Yolk is depleted of magnesium and phosphorus during embryogenesis, but excess calcium absorbed from the eggeshell is stored in the yolk. Consequently reserves of calcium in the yolk actually increase 8-fold during embryonic development. Our results reveal that altricial birds manifest patterns of mobilization and deposition of calcium and other elements similar to those described for precocial species. Evolution of altriciality from precocity evidently did not entail major changes in how embryonic birds meet the challenge of obtaining the calcium, magnesium, and phosphorus required for development.     

Early life history of herring larvae in contrasting feeding environments determined by otolith microstructure analysis

Newly hatched autumn-spawned herring larvae Clupea harengus were released in two 2500-m³ outdoor mesocosms and reared over a 2-month period. Hydrographic conditions were similar in the two mesocosms, but the average plankton density was initially more than 10 times higher in mesocosm B compared to mesocosm A (>11⁻¹ v. <0.11⁻¹). Half-way through the experiment the feeding conditions reversed with three times higher average densities in mesocosm A than in mesocosm B (>31⁻¹ v. ∼11⁻¹). Herring larvae were sampled with a 0.3-m² two-chambered net twice weekly, and survivors were harvested by draining the mesocosms at the end of the experiment. Otolith growth trajectories of individual larvae were determined by relating radial otolith size with number of increments from the outer edge of the otolith (days before capture). The increment widths during the first 3 weeks after hatching, including the first-check size, were generally wider among larvae from mesocosm B (relatively good initial feeding conditions) than among those from mesocosm A (poor initial feeding conditions). The otolith growth pattern also confirmed that the surviving herring in mesocosm A belonged to the upper size range of larvae in the mesocosm after only 2–3 weeks from hatching; no such trend was found in mesocosm B. In both mesocosms the otolith size-at-age indicated that with the present sampling gear, herring larvae larger than 20–25 mm were underrepresented in the net samples. The information obtained from otolith-size-at-age is compared with other morphometric and biochemical measures of size and condition of larvae obtained throughout the experiment.