A study of goldfish oocyte meiosisin vitro: effects of 2,4-dinitrophenol and adenosine-5-triphosphate

Germinal vesicle migration (GVM) and/or dissolution (GVD) were measured in goldfish oocytes, treated with 17α, 20β dihydroxyprogesterone (DHP) and other compounds considered to effect the cytoskeleton and oxidative phosphorylation,in vitro. Administration of DHP reinitiated meiotic maturation, increasing GVM and GVD in goldfish oocytes. Addition of 2,4-dinitrophenol (DNP) to the incubation medium significantly inhibited DHP-induced GVM and GVD. The DNP effect was found to be partially reversible after 24 h and could be reversed fully after a further delay of approximately 24h. Treatment of goldfish oocytes with demecolcine (DE; a colchicine derivative also known as colcemid) induces GVM to the micropyle without effecting GVD; while Cytochalasin-B which inhibits microfilament polymerization impairs both GVM and GVD. Administration of DNP, significantly inhibited DE-induced GVM, suggesting that GVM as well as GVD are dependent upon the process of oxidative phosphorylation. Addition of adenosine-5′ -triphosphate (ATP) at low concentrations (0.01–0.1 mM) did not effect DHP-induced or DNP-inhibited GVD in goldfish oocytes. The present results are consistent with the idea that migration of the oocyte nucleus during meiosis reinitiation has an energy requirement and involves participation by the cytoskeleton.     

Effect of Light Intensity on Color Performance of False Clownfish,Amphiprion ocellaris Cuvier

Color performance of false clownfish, Amphiprion ocellaris Cuvier, was examined under three levels of light intensity (20–50 , 600–850 , and 2700–3500 lx) for 5 wk. The experiment was conducted in nine rectangular glass aquaria (25 × 25 × 20 cm) with three replicates. Each aquarium was stocked with 36 fish, and 3 fish were randomly sampled from each aquarium every other week. Digital images were taken weekly on each individual fish after it was anesthetized in MS‐222. The color performance in hue, saturation, and brightness was quantified using image analysis. In addition to the whole‐body analysis, each fish image was divided into ventral and dorsal parts to assess the body position‐dependent effect. Furthermore, color differences between dorsal fin, anal fin, ventral fin, and caudal fin were also quantified. The whole body was brighter at low light than at medium or at high light intensity. Irrespective of light intensity, the dorsal side was more orange but less bright than the ventral side. Brighter light strengthened overall orange color on fish fins. The dorsal fin and ventral fins appeared more orange than the anal and caudal fins regardless of light intensity and exposure duration. Similar to body color, low light also led to brighter fins, especially for caudal and dorsal fins. Our results indicate that ambient light could regulate fish color performance but could not change the pigment dominance by β‐carotene. Light intensity is unlikely to change the contrast between dorsal and ventral sides, but dim light tends to make fish body brighter, and bright light strengthens orange color on fins.     

近60年来克里雅绿洲耕地动态变化驱动力及生态环境效应

利用1950-2008年统计资料和土地详查数据,采用多元统计分析与文献调查,分析了塔克拉玛干沙漠南缘克里雅绿洲近60年来耕地动态变化情况及其驱动机理,并讨论了耕地动态变化对绿洲生态环境的影响。结果表明:(1) 1950-2008年克里雅绿洲耕地面积经历了急剧增加(1950-1961年)→缓慢减少(1962-1990年)→快速增加(1991-2008年)的变化过程,耕地数量总体呈增加趋势,人均耕地面积呈减少趋势;(2)影响克里雅绿洲耕地动态变化的驱动因子可归纳为政策变动、经济发展、人口增长、农业科技进步等四大因素;(3)耕地动态变化某种程度上改善了克里雅绿洲生态环境的同时,导致了绿洲外围沙漠化,绿洲内部土壤盐渍化,湿地减少,河道缩短等一系列生态环境问题,威胁了绿洲稳定性。     

The incidence of canine haematozoa in peninsular Malaysia

In 3 urban areas in Selangor, Peninsular Malaysia between 1973 and 1981, blood from 4080 dogs was examined for haematozoa. The following frequencies were found: Babesia gibsoni 17.7%; microfilariae of Dirofilaria immitis 9.6%; Hepatozoon canis 1.2%; B. canis 1.1%; Ehrlichia canis 0.2%; Trypanosoma evansi 0.1%. A detailed examination of B. gibsoni infections and microfilariasis due to D. immitis with regards to monthly distribution, breed frequency, sex and age, revealed that pedigree and non-pedigree dogs were equally susceptible to Babesia and microfilariae infections.     

Anti-inflammatory activities of cucurbitacin E isolated from Citrullus lanatus var. citroides: role of reactive nitrogen species and cyclooxygenase enzyme inhibition

The in vivo and in vitro mechanistic anti-inflammatory actions of cucurbitacin E (CE) (Citrullus lanatus var. citroides) were examined. The results showed that LPS/INF-γ increased NO production in RAW264.7 macrophages, whereas L-NAME and CE curtailed it. CE did not reveal any cytotoxicity on RAW264.7 and WRL-68 cells. CE inhibited both COX enzymes with more selectivity toward COX-2. Intraperitoneal injection of CE significantly suppressed carrageenan-induced rat's paw edema. ORAC and FRAP assays showed that CE is not a potent ROS scavenger. It could be concluded that CE is potentially useful in treating inflammation through the inhibition of COX and RNS but not ROS.     

Morphinandienone alkaloids from Dehaasia longipedicellata

Five morphinoid alkaloids have been isolated from Dehaasia longipedicellata, namely (-) pallidine, a new alkaloid (+) pallidinine (1), (+)-milonine, (-) 8,14-dehydrosalutaridine and (-) sinoacutine.     

Comparison of effectiveness of introduced barn owls,Tyto javanica javanica,and rodenticide treatments on rat control in oil palm plantations

Journal of Pest Science - In Peninsular Malaysia, barn owls (Tyto javanica javanica) have been utilized as biological control of rats since the 1960s. In this study, the impact of introduced barn...     

Effects of nano-silver impregnation on brittleness, physical and mechanical properties of heat-treated hardwoods

The present study investigates the effect of heat treatment of untreated and nano-silver-impregnated Populus nigra, Populus deltoides and Fagus orientalis on the physical and mechanical properties. Specimens were impregnated with a 200-ppm aqueous silver nanoparticles suspension. Heat treatment was carried out at temperatures of 135 ± 3 °C and 185 ± 3 °C. Nano-silver impregnation aggravated the effects of heat treatment. Although significant in some cases, nano-silver impregnation did not seem to have great effect on physical properties. It may be concluded that although NS impregnation aggravated the effects of heat treatment on solid woods, other factors may also be involved such as the species and density of the wood.     

Alleviation of dormancy in walnut kernels by moist chilling is independent from storage protein mobilization

We studied the effects of moist chilling and warming on storage protein mobilization in walnut (Juglans regia L.) kernels to assess the metabolic inhibition theory, which states that dormant seeds are unable to utilize their own food reserves and that cold conditions allow germination by activating hydrolases involved in reserve mobilization. Stratifying kernels at 5 degrees C for 40 days enhanced their germination. During both cold stratification and warm incubation of kernels, storage protein mobilization occurred in cotyledons rather than axes. Kernel amino acid concentration increased during protein mobilization, with axes of warm-incubated kernels having particularly high amino acid concentrations. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) of the soluble protein fractions from both cold-stratified and warm-incubated cotyledons revealed increased band intensities of putative glutelins (19-22 and 32-35 kDa). A very high molecular weight protease was detected by gelatin SDS-PAGE that was most active at acid to neutral pHs in imbibed, cold stratified and germinated kernels suggesting the protease(s) was synthesized earlier in the mature seeds. Thus, in dormant walnut kernels there is no block to protein mobilization, and imbibition alone is sufficient to initiate proteolysis. Catalase activity was higher in warm-incubated kernels than in cold-stratified kernels, suggesting that seed aging is hastened under warm conditions and that cold stratification in walnut kernels might involve activation of cellular repair mechanisms.     

Study on the effect of nano-silver impregnation on mechanical properties of heat-treated <Emphasis Type="Italic">Populus nigra</Emphasis>

The present study is aimed at investigating the effect of heat treatment of nano-silver-impregnated Populus nigra on weight loss, modulus of rupture (MOR), modulus of elasticity (MOE), and compression parallel to grain. Specimens were impregnated with 200 PPM water-based solution of nano-silver particles at 2.5 bar in a pressure vessel. For heat treatment, both nano-silver-impregnated and simple specimens were kept for 24 h at 45°C and then further for 24 h at 145°C and finally for 4 h at 185°C. MOR decreased from 529 to 461 kg/cm² in heat-treated specimens; MOE and compression parallel to grain were though improved. Also, comparison between heat-treated and nano-silver-impregnated heat-treated specimens showed that there was a decrease in MOR and MOE in nano-silver-impregnated heat-treated specimens. This shows that nano-silver impregnation facilitates transfer of heat in wood and it may increase the process of degradation and pyrolysis of wood structures in deeper parts of specimens.