铅长期暴露对黄河鲤红细胞微核率、核异常率的影响

利用微核观察方法,研究了铅(PbCl2)暴露30 d对黄河鲤红细胞微核率、核异常率的影响。结果表明,染毒Pb2+可引起黄河鲤微核率和核异常率指标发生显著变化,随着染毒Pb2+浓度的增加,黄河鲤红细胞微核和核异常率呈现先下降后上升的规律性变化。同一染毒浓度时染毒时间对于微核和核异常率的影响具有累积效应。     

Intragastric gavage with denatonium benzoate acutely induces neuronal activation in the solitary tract nucleus via the vagal afferent pathway

Natural toxic substances have a bitter taste and their ingestion sends signals to the brain leading to aversive oral sensations. In the present study, we investigated chronological changes in c-Fos immunoreactivity in the nucleus tractus solitarius (NTS) to study the bitter taste reaction time of neurons in the NTS. Equal volumes (0.5 mL) of denatonium benzoate (DB), a bitter tastant, or its vehicle (distilled water) were administered to rats intragastrically. The rats were sacrificed at 0, 0.5, 1, 2, 4, 8, or 16 h after treatment. In the vehicle-treated group, the number of c-Fos-positive nuclei started to increase 0.5 h after treatment and peaked 2 h after gavage. In contrast, the number of c-Fos-positive nuclei in the DB-treated group significantly increased 1 h after gavage. Thereafter, the number of c-Fos immunoreactive nuclei decreased over time. The number of c-Fos immunoreactive nuclei in the NTS was also increased in a dose-dependent manner 1 h after gavage. Subdiaphragmatic vagotomy significantly decreased DB-induced neuronal activation in the NTS. These results suggest that intragastric DB increases neuronal c-Fos expression in the NTS 1 h after gavage and this effect is mediated by vagal afferent fibers.     

Evaluation of effects of multiple candidate genes (LEP,LEPR, MC4R,PIK3C3, and VRTN) on production traits in Duroc pigs

We evaluated multiple effects of genetic variations of five candidate loci (LEP, LEPR, MC4R, PIK3C3 and VRTN) on four production traits (average daily weight gain (ADG); backfat thickness (BFT); loin eye muscle area (EMA); and intramuscular fat content (IMF)) in a closed nucleus herd of pure Duroc pigs. Polymorphisms in LEPR, MC4R and PIK3C3 had significant single gene effects on ADG and BFT. The additive genetic variance in ADG and BFT (16.99% and 22.51%, respectively) was explained by genetic effects of these three loci. No correlations were observed between the LEP genotype and production traits in this study. Although we detected marginally epistatic interactions between LEPR and PIK3C3 on the eye muscle area, there were no significant epistatic effects on any traits among all loci pairs. These results suggest that LEPR, MC4R, PIK3C3 and VRTN may independently influence growth rate and fat deposition. Furthermore, the statistical models for predicting the breeding values of each trait had the lowest Akaike's information criterion values when considering the effect of the MC4R, LEPR, PIK3C3 and VRTN genotype simultaneously. These results suggest that LEPR, MC4R, PIK3C3 and VRTN are useful markers for accurately predicting breeding values in Duroc pigs.     

Over-expression of SK2 channel in PVN reduces renal sympathetic nerve activity in chronic heart failure rats

AIM：To investigate the effect of over-expression of small-conductance calcium-activated potassium channel subtype 2 (SK2) in the paraventricular nucleus (PVN) of hypothalamus on heart rate(HR), mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) of the rats with chronic heart failure (CHF). METHODS：Adenovirus vector encoding SK2 (pDC316-mCMV-EGFP-rKCNN2) was constructed.The CHF model of the male Sprague Dawley (SD) rats was established by the ligation of anterior descending coronary artery. Echocardiogram was used at the 6th week after the operation to identify the CHF model. Adenovirus vector encoding SK2 (pDC316-mCMV-EGFP-rKCNN2) or control adenovirus vector (pDC316-mCMV-EGFP) were transfected into the PVN in vivo. The cardiac function was monitored by echocardiogram. The expression of SK2 at mRNA and protein levels was determined by RT-PCR, Western blotting and immunofluorescence. The HR, MAP and RSNA were measured by PowerLab 8/30 in anesthetized rats with bilateral PVN microinjection of SK channel blocker apamin. RESULTS：Treatment with pDC316-mCMV-EGFP-rKCNN2 significantly decreased the renal sympathetic nerve activity in the rat with CHF. Injection of pDC316-mCMV-EGFP did not change the renal sympathetic nerve activity in the rats in sham group. CONCLUSION：The expression and function of SK channels in PVN in the heart failure rats were decreased, suggesting a reduced negative regulation of sympathetic activity in central neural system. Increased expression of SK2 in the PVN leads to a reduction in sympathetic outflow under the condition of CHF, which may provide a new target for the treatment of heart failure.     

Role of anterior thalamic nucleus in trigeminal nerve electrostimulation-induced reduction of seizures and hippocampal damage

AIM：To investigate the role of anterior thalamic nucleus in trigeminal nerve electrostimulation (TNS)-induced effects on seizures and hippocampal damage. METHODS：The rats were intraperitoneally injected with pilocarpine to induce chronic epilepsy, and then received sham treatment, TNS treatment and TNS treatment after stereotactic lesion to the anterior thalamic nucleus. The TNS treatment lasted for 1 month in each group. Another injection of pilo-carpine was conducted to induce seizures, and the severity and duration of seizures were quantitatively evaluated. TUNEL, Fluoro-Jade B (FJB) and Nissl staining were applied to determine in situ apoptosis, neuronal degeneration and neuron loss in the hippocampal CA1 area respectively. RESULTS：Compared with TNS group, TNS treatment after stereotactic lesion to the anterior thalamic nucleus significantly increased the severity and duration of seizures (P<0.05), and the numbers of TUNEL positive cells, FJB positive cells and lost neurons in the hippocampal CA1 area (P<0.01). CONCLUSION：Anterior thalamic nucleus plays a role in TNS-induced reduction of seizures and hippocampal damage. The mechanisms might be due to the chronically activation of the cortex through anterior thalamic nucleus pathway induced by TNS, resulting in the down-regulation of neuronal excitatory susceptibility.     

Prevalence,pathology and risk factors for coccidiosis in domestic rabbits (Oryctolagus cuniculus) in selected regions in Kenya

Background: The potential for rabbit production in Kenya is high. However, high morbidity and mortality of domestic rabbits were reported.

Objective: The aim of the study was to determine the pathology, prevalence and the predisposing factors to coccidiosis in domestic rabbits in selected regions in Kenya.

Animals and methods: A total of 61 farms keeping rabbits in six different counties were visited in the survey. A total of 2680 live rabbits were examined and 61 rabbits and 302 fecal samples were randomly collected from the farms and examined for coccidian oocysts by ante-mortem and post-mortem methods. The predisposing factors to coccidiosis were assessed through questionnaires and direct observation. Chi square (χ²) statistics was used with P values < 0.05 considered statistically significant.

Results: Of the 302 fecal samples, 85% (P < 0.001) contained coccidian oocysts and 2% harbored nematode eggs (Passalurus ambiguous). The overall prevalence of Eimeria spp. infestation was 85.1% in the study area and 90.2% in the individual rabbits, while prevalence of intestinal coccidiosis and hepatic coccidiosis was 29.5% and 11.5%, respectively. Higher counts of coccidian oocysts per gram of feces were recovered in weaners than in growers and adults rabbits (P < 0.001), rabbits that were kept in high density group housing (P < 0.05) and housing with more than two tiers.

Conclusion: This study identified group housing of rabbits of different ages and inadequate control of concurrent infections as the major risk factors associated with coccidiosis in domestic rabbits in Kenya.     

马立克氏病淋巴瘤的细胞化学及图像分析

经ATPase、ACP和ANAE染色表明,马立克氏病(MD)淋巴瘤中具有T细胞标志的约占66%,B细胞标志的约占25%,巨噬细胞约占9%.MD肿瘤按细胞形态分为两类:单一小淋巴细胞肿瘤和多形态的淋巴细胞肿瘤.图像分析表明,前者肿瘤细胞比较小,大小均匀一致,核平均面积3.24±0.59μm~2,仅为正常胸腺细胞核面积的一半,其中2～4μm~2的细胞占90%以上,分布集中.后者肿瘤细胞形态各异,大小不一,同一病鸡不同脏器的肿瘤,在细胞核平均面积、核积分光密度、核平均光密度方面差异不显著,从而证实MD内脏肿瘤细胞的一致性.     

甜椒雄性不育系AB91选育及研究初报

1986年在英格拜尔甜椒中发现一株雄性不育材料,经6年的培育研究,其雄性不育株率稳定在50%,系内兄妹交不育株与可育株分离比例为1:1,初步认为不育性系由一对隐性核基因控制,可培育成两用系,定名为 AB_(91)。该不育系从花器官到结实能力及经济性状等均表现优良,配合力也高,易于选配优良杂交种,是个较理想的雄性不育两用系。AB_(91)的发现及研究为甜椒杂种优势利用开避了一条新途径,具有较大的实用价值和学术价值。     

大鼠下丘脑室旁核在高张NaCl溶液抗失血性低血压中的作用

用大鼠股动脉放血致矢血性低血压的实验模型，以观察下丘脑室旁核（ＰＶＨ）在注射高张ＮａＣｌ溶液引起的升压反应中的作用。结果表明：（１）ＰＶＨ电损毁或假损毁后，小剂量高张ＮａＣｌ溶液静脉注射引起动脉血压（ＡＰ）有意义地迅速回升，但５ｍｉｎ后开始下降，损毁组下降速度快，３５ｍｉｎ后，平均动脉压（ＭＡＰ）回降至注射前水平。组间比较，２０ｍｉｎ后，损毁组ＭＡＰ回升值明显低于假损毁组（Ｐ＜０．０５）。（２）失血后５ｍｉｎ内假损毁组ＨＲ有意义地减慢；明显低于损毁组（Ｐ＜０．０５）。（３）ＰＶＨ微量注射高张ＮａＣｌ溶液（ＨＳ组）后，ＡＰ有意义地回升。对照组（ＮＳ组）则无明显回升。组间比较，ＨＳ组ＡＰ值显著高于ＮＳ组。结果提示：ＰＶＨ参与高张ＮａＣｌ溶液抗矢血性低血压时的升压反应，在血压恢复后的维持阶段起重要作用。     

白色金针菇原生质体单核菌系的建立及其遗传特性分析

利用原生质体技术获得的白色金针菇原生质体再生菌株,根据细胞核的分布与数目以及锁状联合的有无,选出25株单核菌株,对峙试验表明,这些单核株分为核基因型不同的两种类型。两种类型的单核株和始发双核菌株的菌落形态、生长速度、胞外漆酶活性和药物抗性等性状指标均有明显差异,表明生成原生质体的过程中,所再生的单核株发生了变化。