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21.
Urbanization and industrialization have placed most of the aquatic environments in developing countries at great risk. The absence of reliable biological monitoring programmes further complicates the situation. In this study, an attempt was made to assess incidence of deformities among Chironomus spp. response to the level of environmental degradation. For this purpose, chironomid larvae were sampled from Sebeta River (November, 2012) using Surber sampler and/or D‐frame dip net. Moreover, physico‐chemical analysis of the water and sediment heavy metal analysis were carried out at three study sites. The results indicate that most physico‐chemical variables were higher at the downstream sites (P < 0.05), together with high levels of Cr, Zn and Cu, which was attributed to untreated effluents that originated from garment and tannery industries. Several forms of deformities (mentum gap, notch, tooth missing and breakage) were encountered, and the majority occurred on mentum followed by pecten epipharynx. Taking 8% as a cut‐off value for normal deformities and the moderate rate of deformities detected (16.62% at Sb‐2), it is possible to conclude that the ecological state of Sebeta River is at critical condition. Therefore, corrective measures like designing of effective treatment plants and timely set environmental impact assessment must be in place prior to any developmental activity.  相似文献   
22.
Vertebral deformities in salmonid interspecific hybrids, some of which were triploidised, were assessed across three separate year classes during the freshwater life stage. Initially, eggs from a farmed Atlantic salmon Salmo salar were crossed with the sperm from a S. salar, arctic char Salvelinus alpinus or brown trout Salmo trutta. For S. salar × S. trutta, half the eggs were triploidised. In a second- and third-year class, the eggs from a farmed S. salar were crossed with the sperm from either a S. salar or a S. trutta, and half of each group was triploidised. In the two initial-year classes, all hybrids were larger than the S. salar controls, and triploid S. salar × S. trutta were larger than diploid counterparts. In the third-year class, the S. salar × S. trutta were smaller than the S. salar, in contrast to the initial 2 year classes, although the triploid hybrids were still larger than the diploids. In the third-year class, a high degree of spontaneous triploidy was also observed in the putative diploid groups (between 16 and 39%). Vertebral deformities were consistently higher in pressure-shocked triploids than diploids, irrespective of hybridisation, but there was no consistent effect of hybridisation among experiments. Although this study was not able to explain the contrasting results for vertebral deformities between year classes, triploid S. salar × S. trutta can demonstrate impressive freshwater growth that could be of interest for future farming programmes.  相似文献   
23.
Morphological changes in the polyhedra of the Bombyx mori L. nuclear polyhedrosis virus (BmNPV), a baculovirus causing the deadly grasserie disease in silkworms, brought about by mixing with lipophilically capped amorphous silica nanoparticles (LASN, average size 10 ± 2 nm) were studied with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. SEM shows that the regular octagonal polyhedra facets are replaced by a larger number of newly formed irregular ones. The average number of facets reveals a nonlinear growth pattern with nanoparticle (NP) concentration, where an initial linear region ends in a plateau. IR bands corresponding to vibration modes of the capping show (a) a saturation of the area under the band with NP concentration, indicating a correlation with attachment to viral polyhedra and (b) a narrowing of the band per NP from the linear to the plateau portions of the distortion curve, suggesting non-equilibrium and equilibrium situations, respectively.  相似文献   
24.
盐度对条石鲷胚胎发育的影响   总被引:2,自引:0,他引:2  
为了确定条石鲷胚胎孵化的适宜盐度,在试验水温为23.0℃~25.2℃条件下,设置了8个盐度组进行条石鲷胚胎孵化试验,研究了盐度对条石鲷胚胎发育的影响。结果表明:低盐度和高盐度对胚胎有持续性伤害,均可造成胚胎和卵黄球在卵裂期收缩而死亡,一部分胚胎在原肠期之后收缩死亡;低盐度可造成初孵仔鱼畸形率增加,主要引起仔鱼脊柱"L"形和"C"形弯曲,而高盐度可导致胚体胚孔关闭以后尾部的畸形发育;通过分析各盐度组的孵化率、仔鱼畸形率和盐度之间的关系,得出健康仔鱼比例(PHL)和盐度(S)的关系式为PHL=-0.0018S2-0.1135S-0.8853(R2=0.948),以PHL70%为适宜孵化盐度范围,以PHL90%为最适孵化盐度范围,由此确定在23.0℃~25.2℃条件下,条石鲷的适宜孵化盐度范围为21~42(PHL70%),最适为30~33(PHL90%)。  相似文献   
25.
目的通过对Mix-G200益生菌粉的安全性毒理学进行研究,为以后的应用提供科学依据。方法采用雌雄小鼠急性毒性试验、小鼠骨髓细胞微核试验、小鼠精子畸形试验、Ames试验和大鼠30天喂养试验等对Mix-G200益生菌粉进行安全性试验研究。结果急性经口毒性试验表明,Mix-G200益生菌粉对雌雄小鼠的急性经口LD50均大于21500 mg/kg,以急性毒性半数致死量毒性分级,属无毒级物质。小鼠骨髓细胞微核试验、小鼠精子畸形试验、Ames试验结果均为阴性。30天喂养试验结果表明,大鼠生长情况良好,血液学检查、生化学检查、主要脏体以及组织学检查结果与对照组相比,差异均无统计学意义。结论 Mix-G200益生菌粉未见遗传毒性,使用Mix-G200益生菌粉是安全可靠的。  相似文献   
26.
雄性不等单蚤生殖器官畸形二例   总被引:2,自引:1,他引:1  
本报道了二例雄性不等单蚤生殖器官畸形标本,系实验室长期饲养繁殖的。导致畸形的因素难以排除近亲交配的可能.  相似文献   
27.
本文对42例克汀病人进行了全面检查,结果表明:克汀病患者发育滞后,瞳距增大,性发育滞后,多数病人出现聋哑;锥体和锥体外系受损出现生理反射亢进,病理反射阳性征。眼外肌麻痹等体征,主要见于神经型;脑CT显示:颅内钙化率增高、脑沟池增宽、脑室扩大。神经系统损伤部位有较强的选择性,脑发育不良导致精神发育迟滞。严重的骨骼发育障碍,呈多关节畸形,如膝关节,呈X型或O型腿  相似文献   
28.
29.
Visual symptoms of stem deformity similar to those of Cu deficiency are common inP. radiata established on fertile sites previously used for agricultural production in south-eastern Australia. In this study, Cu fertiliser was applied at rates of 0, 2, 5, 10, 20 and 50 kg ha−1 to deformedP. radiata at ages 3 and 6 years. Available soil Cu and contents of Cu in the foliage increased significantly only in the younger plantation. Cu fertiliser did not affect growth nor did it improve stem form. Levels of N, Cu and Cu/N ratios in foliage of straight and deformed trees were similar. However, contents of Cu in apical buds were significantly lower in deformed trees. It was concluded that stem deformity inP. radiata as observed on these fertile pasture sites, cannot be corrected by application of Cu fertiliser. Differences in Cu levels in apical buds of straight and deformed trees suggest that Cu may still be involved in this syndrome. There was also no indication of other nutrient deficiencies that could be associated with the deformity.  相似文献   
30.
目的:探讨胎儿肢体畸形超声特征及诊断价值。方法:采用连续顺序追踪法对66342 例妊娠12-40 周孕妇行胎儿四肢畸形筛查。将产前超声诊断结果与引产或产后结果进行对比分析。结果:发生肢体畸形271 例,发生率为0.41 %(271/66342),包括四肢短小5 例,桡骨发育不全1 例,缺肢畸形5 例,足内翻17 例,手掌畸形3 例,指趾畸形222 例及骨骼多发畸形18 例。其中产前诊断胎儿肢体畸形49 例;漏诊222 例,包括:足内翻3 例、指趾畸形218 例、多发骨骼畸形1 例。胎儿肢体畸形的出现率和产前检出率分别为:四肢短小1.84 %(5/271)、100 %(5/5);桡骨发育不全0.36 %(1/271)、100 %(1/1);缺肢畸形1.84 %(5/271)、100 %(5/5);足内翻6.27 %(17/271)、82.35 %(14/17);手掌畸形1.10 %(3/271)、100 %(3/3);指趾畸形81.91 %(222/217)、1. 8%(4/222);多发骨骼畸形6.64 %(18/271)、94.44 %(17/18)。结论:超声对胎儿手掌、脚掌部位以上畸形的检出率较高。指趾畸形出现率最高,但检出率最低。  相似文献   
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