不同生长环境下水稻结实率数量性状位点的检测

以籼稻密阳23与粳稻吉冷1号配制所获得的F_2:3群体200个家系作为作图群体，在北京、昆明、三亚、公主岭和韩国春川等5个点进行水稻结实率的鉴定，并利用SSR标记对水稻结实率数量性状位点进行检测。结果表明，水稻结实率表型值及其在F₃家系群中的分布以及所检测到的QTL数目因生长环境不同而有较大差异，说明QTL与环境有明显的互作效应。水稻结实率在F₃家系群中呈接近正态或偏态的连续分布，是多个基因所控制的数量性状。共检测到与水稻结实率相关的QTL 14个，分布于第1、2、3、4、6、7、8、10和12染色体上，对表型变异的贡献率为4.9%～15.3%。分别位于第1、2、6和12染色体RM1~RM259、RM263~RM6、RM340~RM30、RM270~RM17区间的qSSR1、qSSR2、qSSR6和qSSR12至少在2种生长环境下均检测到，对表型变异的贡献率分别为4.9%～8.4%、4.8%～7.2%、7.6%～10.7%和7.4%～10.4%。以上多数QTL增效等位基因均来自吉冷1号，基因作用方式主要为部分显性或显性或超显性。     

Stochasticity dominates assembly processes of soil nematode metacommunities on three Asian mountains

Nematodes play an important role in ecosystems; however, very little is known about their assembly processes and the factors influencing them. We studied nematode communities in bulk soils from three Asian mountain ecosystems to determine the assembly processes of free-living nematode metacommunities and their driving factors. On each mountain, elevations span a range of climatic conditions with the potential to reveal assembly processes that predominate across multiple biomes. A phylogenetic nu...     

Numerical study on two-phase flow in horizontal pipe

Two-phase flow in a horizontal pipe was investigated by using numerical and experimental visualization methods.A horizontal pipe was built for qualitative and quantitative flow visualization.The length of horizontal pipe flow system was 9.5 m and the inner diameter was 51 mm.High-speed video method was used for the qualitative visualization and PIV method was applied for the quantitative visua-lization.The same geometry model was used for the numerical study.Three flow regimes including stratified flow,elongated bubble and slug flow field were generated and visualized by using numerical and experimental methods.The results show that the numerical simulation results are qualitatively si-milar to that of the experimental results.In addition,more quantitative results can be analyzed by numerical method.Development and decay process of slug flow was investigated,showing that the decay of slug heavily depends on the magnitude of nose velocity and its lasting time.It can also be found that the liquid superficial velocity plays a significant role in affecting the slug frequency.When keeping the gas superficial velocity constant,the frequency will increase with the liquid superficial velocity.     

多棘海盘车诱导排卵最佳KCl剂置以及水温和盐度对胚胎和幼虫发育的影响

海星的大量繁殖与入侵可对滩涂养殖贝类造成极大威胁.对海星繁殖生物学的研究可为有效控制海星过度增殖提供信息,同时也可为其胚胎和幼虫培育以及发育生物学的深入研究奠定基础.本研究以韩国和中国沿海常见的多棘海盘车(Asterias amurensis)为材料,研究KCl诱导海盘车排放生殖细胞的最佳剂量,以及水温和盐度对胚胎和幼虫发育的影响.采用不同剂量(1.0mL、3.0mL、5.0mL和7.0mL)0.5mol/L KCl注入性成熟海盘车体腔,皆可诱导生殖细胞的排放,3mL注射组的排放个体比例最高(80%),雌性个体排卵量最大(536.5×104个/ind),同时用诱导获得的精/卵进行人工授精后也获得了较高的受精率(92.7±2.9)%.水温和盐度对多棘海盘车胚胎和幼虫的存活率具有显著的影响.在盐度为35时,20℃时多棘海盘车羽腕幼虫的存活率最高(90.1±2.1)%,15℃时次之(84.4±5.2)%.在温度为15℃时,盐度为35时幼虫培养60 h后存活率最高(87.6±4.1)%,盐度为30时次之(85.4±4.0)%.多棘海盘车各期胚胎和幼虫的发育速度(1/t,h-1)随水温升高而加快,在一定温度范围内有明显的正相关性,其关系式为:至2-细胞:1/t=0.110 8Tw-0.599 7(r2=0.946 5);至8-细胞:1/t=0.045 4Tw-0.233 4(r2=0.947 7);至桑椹胚:1/t=0.017 9Tw-0.067 9(r2=0.868 7):至囊胚:1/t=0.004 2Tw(r2=0.89);至羽腕幼虫:1/t=0.000 6Tw-0.008 7(r2=0.878 4).盐度为35时,胚胎和幼虫的发育速度最快,发育至羽腕幼虫需55.4 h.根据不同水温和盐度条件下,胚胎和幼虫的存活率和发育速率,确定15～20℃是多棘海盘车发育的适宜温度,最适温度为20℃;适宜盐度为30～35,最适盐度为35.     

Comparison of in vitro vitellogenin synthesis among different nonylphenol products using primary cultures of tilapia hepatocytes

Effect of nonylphenol (NP) products from different companies on in vitro vitellogenin (VTG) synthesis was compared using tilapia ( Oreochromis mossambicus ) hepatocytes cultures. Addition of NP at a concentration of 10⁻³ M to the medium caused death of hepatocytes (NP-A and NP-B) and delay of monolayer formation (NP-C). No cell death was observed at a concentration of 10⁻⁴ M (NP-A, -B and -C) but cell adhesion was slower than control. These results suggest that high concentration of NP is toxic against tilapia hepatocytes. When effects of estradiol-17β (E₂, 10⁻⁷ M) and NP (10⁻⁴ M) on in vitro VTG synthesis were examined, addition of E₂ and NP-A and NP-B to the media resulted in elevation of VTG. NP-C did not induce VTG in the medium. Co-treatment of NP-B and tamoxifen, a non-steroidal anti-estrogen, reduced VTG synthesis. These results suggest that NP has estrogenic potential in primary cultures of tilapia hepatocytes and acts through binding to the estrogen receptor, and that there is a difference in the induction level of VTG among different NP products.     

Modelling herbicide dose and weed density effects on crop:weed competition

The effects of a range of herbicide doses on crop:weed competition were investigated by measuring crop yield and weed seed production. Weed competitivity of wheat was greater in cv. Spark than in cv. Avalon, and decreased with increasing herbicide dose, being well described by the standard dose–response curve. A combined model was then developed by incorporating the standard dose–response curve into the rectangular hyperbola competition model to describe the effects of plant density of a model weed, Brassica napus L., and a herbicide, metsulfuron‐methyl, on crop yield and weed seed production. The model developed in this study was used to describe crop yield and weed seed production, and to estimate the herbicide dose required to restrict crop yield loss caused by weeds and weed seed production to an acceptable level. At the acceptable yield loss of 5% and the weed density of 200 B. napus plants m^–2, the model recommends 0.9 g a.i. metsulfuron‐methyl ha^–1 in Avalon and 2.0 g a.i. in Spark.     

VIRTUAL CT OTOSCOPY OF THE MIDDLE EAR AND OSSICLES IN DOGS

Virtual otoscopy enables noninvasive 3D endoluminal imaging of the middle ear through postprocessing of computed tompgraphy (CT) data. A standardized imaging approach for the middle ear was established in six normal dogs in an attempt to optimize the clinical application and student education. High‐resolution CT data were obtained. Virtual otoscopic images of the middle ear cavity and ossicles were generated using commercially available software. The views of the four different directions (the ear canal, tympanic bulla, eustachian tube, and ossicular chain) were made for virtual otoscopy. The promontory, cochlea window, tympanic bulla, septum bulla, and auditory tube were distinguished easily and clearly. One of the ossicles, the malleus, was visualized accurately. However, small structures such as the incus and stapes always could not be seen. The main advantage of virtual otoscopy is not only to provide diagnostic information but also to enhance the quality and efficiency of student education, because it contributes to an understanding of the anatomy of the middle ear. We describe the normal topographical 3Dimages of the middle ear of the dog using virtual otoscopy.     

Effect of placenta feeding to sows on plasma biochemical composition and growth of their piglets

The objective of the present study was to investigate the effects on the plasma biochemical composition and growth of piglets of placenta‐fed sows. The experimental animals were a total of 21 sows (L × LW) of third parity, and each sow was suckled by 11 ± 1 piglets. Sows fed without placenta were considered as the control (C), treatment 1 (T1) were placenta‐fed from days 1–7 after farrowing and treatment 2 (T2) were placenta‐fed from day 7 before farrowing to day 7 after farrowing. Glucose of piglets was lower (P < 0.05) in T2 than C and T1 on day 10. Total cholesterol of piglets was higher (P < 0.05) in T2 than C on day 4. Fe of piglets was higher (P < 0.05) in T2 than C on days 4, 20 and 30. Unsaturated iron‐binding capacity was lower (P < 0.05) in T2 than C on days 4 and 30. Immunoglobulin G of piglets was higher (P < 0.05) in T1 and T2 than C on days 4 and 10. Daily gain of piglets was higher (P < 0.05) in T1 than C and T2 on day 4 when daily gain was calculated. Total daily gain increased (P < 0.05) by prolongation of placenta feeding period. The results indicate that feeding placenta to sows may improve the plasma biochemical composition and growth of their piglets.     

Systemic infection of Mycobacterium avium subspecies hominissuis and fungus in a pet dog

A 3-year-old neutered female poodle with a long history of dermatophytic skin disease was presented with lethargy, anorexia and progressive weight loss. Abdominal ultrasonography revealed markedly enlarged mesenteric lymph nodes and multiple hypoechoic foci in the spleen. Cytology of the mesenteric lymph nodes and spleen showed granulomatous inflammation with fungal organisms and negatively stained intracytoplasmic bacterial rods consistent with Mycobacteria spp. Based on culture, multiplex polymerase chain reaction and sequence analysis, the bacterium was identified as Mycobacterium avium subspecies hominissuis. Despite treatment with antibiotics, the dog’s condition deteriorated, and it died approximately 3 weeks after first presentation.