Genetic variation in coumarin hydroxylase activity in the mouse (Mus musculus)

Basal and phenobarbital-induced rates of hepatic metabolism of coumarin to 7-hydroxycoumarin are markedly higher in DBA/2J mice than they are in the AKR/J, C57BL/6J, and C3H/HeJ strains. Intermediate coumarin hydroxylase activity in F(1) hybrids of mating between DBA/2J and the other three strains indicates an additive mode of inheritance.     

Ah locus: genetic differences in susceptibility to cataracts induced by acetaminophen

The Ahb/Ahb homozygous and the Ahb/Ahd heterozygous inbred mouse strains from the (C57BL/6)(DBA/2)F1 X DBA/2 backcross are genetically responsive to 3-methylcholanthrene. They both also develop, within 6 hours after a large intraperitoneal dose of acetaminophen, an irreversible opacity in the anterior portion of the lens. Such cataract formation does not occur in similarly treated nonresponsive inbred strains or nonresponsive Ahd/Ahd individuals from the same backcross. Differences in acetaminophen metabolism and toxicity are associated with the Ah locus in the mouse, and differences in heritability at the Ah locus exist in the human. Our ophthalmologic findings may be important clinically to certain patients receiving either a single large overdose of this drug or high doses over a long period.     

Genetic variation of cholesterol ester content in mouse adrenals

Total cholesterol concentrations in muscle, liver, and plasma do not differ significantly between adult male C57BL/10J and DBA/2J mice. In the adrenal glands of these two strains, of their hybrids, and of AC mice, concentrations of free cholesterol vary by 5 percent. Adrenals from C57 mice, however, contain six times as much esterified cholesterol as adrenals from AC or DBA mice. The intermediate concentrations of cholesterol esters in F(1) hybrids suggest that the difference in this measure is inherited additively. The finding of variation in adrenal cholesterol within a species is useful for the further study of the role of cholesterol in steroidogenesis by means of genetic analysis.     

Deficiency of a kidney metalloproteinase activity in inbred mouse strains

Kidneys from BALB/c mice contain a potent metalloendoproteinase, termed meprin, that is active against large proteins as well as small peptides. The enzyme is present in mouse strains C57BR/cdJ, C57BL/6J, BALB/cJ, A/J, DBA/IJ, CD/l, Swiss, and ICR. Three related inbred strains, CBA/J, CBA/CaJ, and C3H/He, are markedly deficient in this enzymatic activity. This is the first report of a heritable deficiency of an intracellular proteinase in mammalian tissues. Meprin deficiency appears to have arisen as an early event in the development of the C stock. Furthermore, meprin is present in the progeny of a cross between a meprin-sufficient female (C57BL/6) and a meprin-deficient male (C3H/HeN), an indication that the trait for the deficiency is recessive.     

实验小鼠肠道寄生虫观察

本文对开放式设施内饲养的7个品系中351只实验小鼠的肠道寄生虫作了观察。共检出方种寄生虫;毛滴虫、鼠贾第虫、鼠六鞭虫、隐藏管状线虫、四翼无刺线虫和微小膜壳绦虫;其感染率为:毛滴虫100%、鼠贾第虫49.57%、鼠六鞭虫22.51%、隐藏管状线虫58.40%、四翼无刺线虫21.94%、微小膜壳绦虫21.37%。     

不同品系小鼠精子冷冻及冻融精子体外受精的研究

采用小鼠精子冷冻、冻融精子体外受精的方法,进行小鼠保种、引种、生物净化及品系标准化的可行性研究,并初步探究小鼠精子冷冻的影响因素。实验选用同一年龄5种不同品系小鼠分别进行精子冷冻、复苏,并比较各品系冷冻效果及冻融精子的体外受精(IVF)率。结果显示,冷冻后各品系小鼠精子复苏存活率约在15%～50%之间;冻融小鼠精子体外受精结果随遗传背景的不同差异显著,受精率分别为:KM小鼠68.4%、ICR小鼠30.3%、DBA/2J小鼠47.2%、C57BL/6J小鼠6.8%、BALB/cA小鼠25%。冻融精子IVF得到的胚胎可以耐受体外培养。     

鸡粪高效除臭菌的组合筛选研究

以正在腐熟的鸡粪、长期堆放鸡粪的土壤和污水沟中的污水为样本,从中分离出132株细菌,经过初筛、复筛,得到除臭效果较好的反硫化细菌8株、硫化细菌4株和亚硝化细菌4株。通过正交设计,研究菌株的组合除臭效果。结果表明：菌株除臭效果主要作用在前期。在不考虑交互作用时,处理C4B3A4的除NH3效果较对照降低55.5%,处理B1C3A2的除H2S效果较对照降低40.0%。在考虑交互作用时,处理C4B3A3的除NH3效果较好,NH3释放量较处理C4B3A4降低14.9%;2个处理的H2S释放量分别较对照减少45.2%和46.9%,但这2个处理效果差异不明显。     

Inheritance of a cardiac arterial asymmetry in mice

A pair of coronary arteries supplies the interventricular septum of the heart of Mus musculus. The members of this pair tend to be of unequal size, which permits distiniction between specimens displaying left asymmetry and those showing righit asymmetry. Three inbred strains (C57BL/1O, DBA/1, and Bulb/c) differ with regard to this asymmetry. However, variation exists within strains, which suggests that nongenetic factors also influence the development of the asymmetry. Right arterial asymmetry is dominant over left asymmetry.     

Rapid loss of tolerance induced in weanling NZB and B-W F1 mice

Young adult mice (30 to 43 days old) of autoimmune NZB and BIW F(1) strains failed to develop immunologic tolerance when treated with ultracentrifuged bovine gamma globulin and then challenged 12 days later. By contrast, weanling NZB and B/ W F(1) mice (18 to 25 days) as well as weanling C3H mice (16 to 19 days) became tolerant and had no serum antibody 12 days after challenge. The C3H mice remained unresponsive, but NZB and B! W F(1) mice produced antibody between days 27 and 41. The rapid loss of previously established tolerance to foreign antigens could have its parallel in the loss of tolerance to autoantigens with subsequent development of lupus nephritis and Coombs' positive hemolytic anemia in these animals.     

Susceptibility to two strains of Friend leukemia virus in mice

A mutant strain of the Friend leukemia virus is described. The parental virus strain, passaged through ICR/Ha mice, shows no or very little activity by the spleen-focus assay in BALB/c mice (by comparison with highly susceptible DBA/2 and ICR/Ha mice) and produces typical Friend disease in these mice only exceptionally; susceptibility to this strain of virus is recessive in the (C57BL/6 x DBA/2) F(1). By contrast, the mutant virus strain is as active in BALB/c mice as in DBA/2 or ICR/Ha mice; susceptibility to the mutant virus strain is dominant in the (C57BL/6 x DBA/2) F(1).     

Male-specific antigen: modification of potency by the H-2 locus in mice

Skin grafts from C57BL/10 (B10) male mice survive significantly longer than do B10.BR male skin grafts on (B10 x X B10.BR)F(1) females. This indicates that the H-2 locus influences the potency of the male-specific antigen in mice.     

小麦染色体3B和4B雌性育性遗传位点的初选

以普通小麦N8×小麦雌性不育系XND126组合衍生的F2为基本群体,从中选择100株隐性极端不育株构成极端不育群体,以2008-2010年关联分析中的38个SSR阳性关联标记为基本线索进行PCR和电泳实验。与N8带型相同的记为A;与XND126带型相同的记为B;与F1带型即杂合带型相同的记为H。以c=(N1+N2/2)/N计算c值,以c值小于0.4确定标记与位点可能的连锁关系。以初选的c值相对较小的标记为线索,在其参考连锁图上寻找并合成第二批标记引物,再次筛选,共得到3个位于3B染色体上的候选标记Xwmc687(c值为0.360),Xbarc206(c值为0.35)和Xcfb3440(c值为0.375),以及1个位于4B染色体上的候选标记Xgwm495(c值为0.295)。实验结果显示,除本实验室前期定位的小麦雌性育性2DS位点外,3B和4B上可能存在与小麦雌性育性有关的遗传位点。     

Leukemogenesis by urethan in C57B1 mice bearing isologous tissues from x-irradiated mice

A single exposure of mice of a low-leukemic strain (C57B1/6) to 400 r of total-body x-irradiation caused the early appearance of a factor which, though not itself capable of inducing leukemia in adult C57B1 recipients, did cause its appearance when the recipients also received urethan by injection. Positive results were obtained with seven different tissues from irradiated animals, whether urethan was injected 1 day or 30 days after the irradiation. No such effect was obtained in either series in the absence of urethan treatment. When urethan was injected into normal C57B1 mice, or into mice previously implanted with tissues from nonirradiated mice, only marginal leukemogenic activity was evinced. The possible involvement of a precursor virus is discussed.     

H-2-linked resistance to mastocytoma in male mice: immune response to a histocompatibility antigen on the X chromosome

Male hybrids from a cross between female mice of strain C57BL/6Kh and males of strain DBA/2J lived longer after injection of P815 mastocytoma cells of DBA/2 origin than did their female siblings. Responses to the histocompatibility antigen on the X chromosome of the DBA/2 strain may be involved in resistance to the tumor. When the female parent was replaced with a C57BL/6Kh carrying one of several mutations in the H-2 region, this sex effect disappeared in some of the hybrid combinations. Thus, the H-2 complex appears to be involved in the regulation of the immune response to the X-linked histocompatibility antigen in this tumor model.     

不同品系小鼠体外受精方法的研究

对CD-1、B6DF1和C57BL／6小鼠的卵母细胞采用直接、去卵丘细胞、切割透明带法处理后,分别进行体外受精、体外培养和胚胎移植试验。结果表明：CD-1和B6DF1小鼠体外受精率及受孕率均高于近交系C57BL／6小鼠。3个品系小鼠卵母细胞3种不同处理试验,受孕率差异均不显著;去卵丘细胞卵体外受精率(11％～23％)均显著低于卵丘卵母细胞复合体的受精率(34％～60％)和切割透明带卵的受精率(48％～65％),而C57BL／6小鼠的卵经切割透明带后体外受精率显著高于卵丘卵母细胞复合体的受精率。C57BL／6小鼠理想的体外受精方法为切割透明带法,而CD-1、B6DF1小鼠切割透明带卵受精率与其卵丘卵母细胞复合体的受精率差异均不显著,因此这2个品系可直接用卵丘卵母细胞复合体进行体外受精,其方法简单、有效。     

继代移殖对球孢白僵菌蛋白酶、几丁质酶、脂肪酶活性的影响及与毒力的相关性

为探讨继代移殖对球孢白僵菌蛋白酶、几丁质酶、脂肪酶活性的影响及与毒力的相关性,以筛选得到的高毒力菌株B5、 BXS与低毒力菌株B11、BZ为出发菌株,通过连续接种松墨天牛幼虫获得H1、H2、H3、H4继代移殖菌株,而连续在PPDA培养基上转接,获得R1、R2、R3和R4继代移殖菌株。分别对各原始菌株与继代移殖菌株进行蛋白酶、几丁质酶、脂肪酶活性与毒力测定,并将每种酶活性与相应菌株对松墨天牛的半致死时间（LT50）作相关性分析。结果表明:高毒力菌株B5、BXS与低毒力菌株B11、BZ在PPDA培养基上继代移殖,随着各菌株对松墨天牛的毒力逐代下降,其蛋白酶、几丁质酶、脂肪酶活性也逐代降低;来源于松墨天牛的B5、BXS、B11菌株通过松墨天牛幼虫继代移殖后随着毒力逐代提高,3种酶活性也逐代上升,但来源于松毛虫的BZ菌株逐代之间3种酶活性差异不显著;相关性分析表明4个原始菌株与继代移殖菌株彼此间的LT50与3种酶活性间均呈极显著的直线负相关。      

地毯草根际固氮菌的分离及鉴定

结合气相色谱仪,利用乙炔还原等方法对地毯草(Axonopus compressus)根际固氮菌进行分离和鉴定。结果表明,从地毯草根际土壤中分离获得6株固氮菌株,菌株的固氮酶活性相差较大(92.5 C2H4~295.2 C2H4nmol.mL-1.h-1),菌株hnN2及hnN6具有较高的固氮酶活性(>200 C2H4nmol.mL-1.h-1);菌株经鉴定分属Bacillus(2株)、Azotobacte(r 3株)和Pseudomona(s 1株)3个属。     

高产纤维素酶木霉菌株的筛选

从18株木霉中筛选出产纤维素酶能力较强的菌株。将18株菌株活化处理后接种于液体发酵培养基上,在30℃,转速为180r／min条件下摇床培养7d,抽滤,得粗制酶液。通过对滤纸酶活力测定的反应中观察,菌株H4、F1、C11、H2、BI、05、A13分解滤纸务效果较好,然后分别测此7株木霉的羧甲基纤维素酶、滤纸酶、β-葡萄糖苷酶活力,综合比较后,筛选出H4、F1和C113株产纤维素酶能力较高的菌株。     

Tryptophan hydroxylase-2 controls brain serotonin synthesis

Dysregulation of brain serotonin contributes to many psychiatric disorders. Tryptophan hydroxylase-2 (Tph2), rather than Tph1, is preferentially expressed in the brain. We report a functional (C1473G) single-nucleotide polymorphism in mouse Tph2 that results in the substitution of Pro447 with Arg447 and leads to decreased serotonin levels in PC12 cells. Moreover, in BALB/cJ and DBA/2 mice that are homozygous for the 1473G allele, brain serotonin tissue content and synthesis are reduced in comparison to C57Bl/6 and 129X1/SvJ mice that are homozygous for the 1473C allele. Our data provide direct evidence for a fundamental role of Tph2 in brain serotonin synthesis.