Mammary gland development during pregnancy in the dwarf mouse mutant, little

Little (lit) is a single gene dwarf mutation described in the C57Bl/6J strain of laboratory mouse. This study was designed to determine the effect of the mutation little on mammary gland development during pregnancy and post-partum periods. Failure of mutant females to lactate at first parturition appears to be due to the endocrine environment of the gland rather than any intrinsic defect of the mammary epithelium. Treatment of primiparous lit/lit females with exogenous growth hormone or prolactin resulted in lactogenesis. Treatment with hydrocortisone resulted in increased amounts of organized rough endoplasmic reticulum but lactation did not occur.     

Growth hormone and insulin binding to isolated hepatocytes in the genetically dwarf mouse

The interaction of growth hormone with its specific receptors in dwarf mice was investigated. (1) The interaction of 125I-labeled human growth hormone with isolated mouse liver cells is a specific, time-dependent and saturable process. Hepataocytes of male and female dw/dw mice bound only 10-20% as much growth hormone per unit of cell surface area as those of their litter mates. Scatchard analysis suggested that this decrease in binding was due to a decreased number of receptor sites in th liver cell of the dwarf mouse. (2) In contrast to the marked decrease in growth hormone receptors, the binding of insulin is higher in dwarf mice than in litter mates, at low hormone concentration. (3) Competition and stoichiometric studies indicate that growth hormone and prolactin bind to the same type of binding site in female and male mouse hepatocytes. These results indicate that dwarfism in this animal was associated with a loss in the number of growth hormone binding sites. The decrease in growth hormone receptors and the increase in insulin receptors correlate well with the respective biological activity of these two hormones.     

Growth and gibberellin relations of the extreme dwarf dx tomato mutant

The extreme dwarf d ^x tomato ( Lycopersicon esculentum Mill.) mutant has very short internodes which were found to contain shorter and fewer epidermal cells. The leaves are highly abnormal. The mutant showed a substantial stem growth response to GA₃, without approaching normal stature or morphology. The active gibberellin GA₁ and its precursors GA₁₉ and GA₂₀ were identified by coupled gas chromatography-mass spectrometry (GC/MS) in d ^x shoots. Quantitative GC/MS revealed that GA₂₀ accumulated to far higher levels than normal in stems and leaves of the mutant.     

Linkage of dwarf with obese in the mouse

The gene for Snell's dwarfism in mice is located in linkage group XI at a distance of about 33 map units from theobese locus which is linked towhite microphtalmia. The order is:dw-ob-mi^wh.     

Immunologic disparity in the hypopituitary dwarf mouse.

The Snell-Bagg hypopituitary dwarf mouse has been shown to be deficient in growth hormone, thyroxine, and prolactin. There are reports indicating that in addition to these neuroendocrine abnormalities, development of immune competence is also severely impaired in these animals. However, other studies indicate that the immunologic potential of these mice does not differ from their heterozygous littermate controls. Our data show that dwarf mice weaned at 21 days of age and killed at that time, or 7 days later, have reduced numbers of cells in both the spleen and thymus and the mitogen responsiveness of these cells is impaired. However, if mice weaned on day 21 are analyzed at 32 days of age or the mice are weaned at day 30 and analyzed 7 days later the ability to respond to mitogenic stimulation does not differ from controls. Further experiments show that dwarf mice weaned at 30 days of age have a normal complement of V-beta TCR as evidenced by immunofluorescence analysis as well as a primary antibody response to SRBC equivalent to that observed in normal littermates. Immunofluorescence analysis of CD4 and CD8 expression on thymocytes obtained from dwarf mice shows a distinct pattern dependent on the time of weaning and time of analysis. Initial analysis of thymocytes from dwarf mice weaned and killed at 21 days of age do not differ from controls. However, cells from dwarf mice weaned on day 21 and killed on day 28 are markedly different with a loss of immature CD4+/CD8+ cells and a corresponding increase in CD4+ and CD8+ mature thymocytes. In contrast, the phenotype of thymocytes obtained from dwarf mice weaned at 30 days of age and killed on day 37 did not differ from normal littermates. Collectively these studies indicate that hypopituitary dwarf mice lag behind their heterozygous littermates with respect to development of immunocompetence but normal immune responsiveness does develop by 32 days of age when the mice are weaned on day 21.     

X-ray microanalysis of cardiocytes in the Snell dwarf mouse

X-ray microanalysis has been used to determine elemental content in the nucleus, myofibrillar cytoplasm and mitochondrially enriched cytoplasm of cardiocytes in Snell dwarf mice in comparison with phenotypically normal mice from the same strain. It was found that there was significantly lower chlorine concentration in all three subcellular locations and significantly lower sodium concentration in the nucleus of dwarf mouse cardiocytes. In both normal and dwarf mice, statistically significant subcellular compartmentalization was found for phosphorus, sulfur, and potassium.     

Characterization of a novel high-tillering dwarf 3 mutant in rice

Tiller number and culm length are important components of plant architecture and determinate grain production in rice.A line SIL046,derived from an introgression lines population developed by an accession of common wild rice (Oryza rufipogon Griff.) and a high-yielding indica cultivar Guichao 2 (Oryza sativa L.).exhibits a higher tiller number and shorter culm length phenotype than the recipient parent Guichao 2 (GC2).Genetic analysis showed that the high-tillering dwarf phenotype was controlled by a novel single recessive gene,referred to as the high-tillering dwarf3 (htd3),which located within the genetic distance of 13.4 cM between SSR makers RM7003 and RM277 on chromosome 12.By means of fine-mapping strategy,we mapped HTD3 gene within the genetic distance of 2.5 cM and the physical distance of 3100 kb in the centromere of chromosome 12.Further identification of HTD3 gene would provide a new opportunity to uncover the molecular mechanism of the development of culm and tiller,two important components of yields in rice.     

岩羊和矮岩羊头骨形态特征比较

本文报道了岩羊和矮岩羊的头骨形态学资料,涉及头骨特征描述和一些形态学指标测定,被测定的指标主要有上颊齿列基长、眼窝长、乳突间距、眶间距、颧宽、枕颅高、枕髁宽、脑颅最大宽、眶下孔距、上颌臼齿外宽、角基最窄、最小角尖距、角尖距、最大角间距、角基周长、角基长径、角基短径、角外侧长,应用判别分析和单变量分析对岩羊和矮岩羊头骨的测量值进行统计与分析,以探讨这两个种头骨之间的形态差异。结果表明：（1）岩羊和矮岩羊头骨在形态上十分相似,但矮岩羊的头骨细长,脑颅狭窄,角直且朝上翘,角内侧具一明显角棱,亦较直,角基部狭窄,老年个体角基部愈合;岩羊的脑颅宽大,角粗大而长,向两侧分开,弯曲度较大,内侧角棱弯曲呈长S型,角尖朝向后方,角基部较宽,不愈合在一起。（2）岩羊和矮岩羊头骨的18项形态测量指标中乳突间距、眶间距、颧宽、脑颅最大宽、上颌臼齿外宽、角基周长、角基长径差异极显著（P〈0.01）,枕颅高、枕髁宽、眶下孔距、角尖距、最大角间距、角基短径、角外侧长差异显著（P〈0.05）;典型判别的正确率：岩羊为100%,矮岩羊为83.3%,交互验证法检验的结果,判别正确率：岩羊100%,矮岩羊为83.3%。这两个判别函数可以从角上区别岩羊和矮岩羊。     

Global gene expression analysis of a rice high-tillering dwarf mutant

Plant height and tiller number are indispensible for the establishment of grain production in rice (Oryza sativa L.). A new rice mutant high-tillering dwarf 3 (htd3) exhibiting more tiller number and shorter culm length than the wild-type Guichao 2 (GC2, an indica cultivar) was used to investigate the global gene expression patterns at days after germination 25 (DAG25) and DAG60. In this study, we identified 305 and 987 genes with at least twofold change in gene expression level at DAG25 and DAG60 respectively using the rice microarray chip. Gene ontology enrichment analysis of these twofold change regulated genes revealed that large numbers of genes were involved in binding activity, catalytic activity and metabolic process. The chip results also showed that some of the regulated genes involved in diverse molecular pathways, including gibberellin pathway, brassinosteroid pathway and auxin signal, had significant differences in gene expression abundance at DAG60. This genome-wide gene expression analysis could provide a new opportunity to uncover the regulation mechanisms of the development of culm and tiller, two important components of yields in rice.     

Altered oxidative stress response of the long-lived Snell dwarf mouse

Several single gene mutations in mice that increase the murine life span have been identified, including the Pit-1 mutation which results in the Snell dwarf (Pit1(dw/dw)), however, the biological mechanism of this life-span extension is still unclear. Based on studies that show oxidative stress plays an important role in the aging process, we hypothesized that the increased longevity seen in Snell dwarf mice may result from a resistance to oxidative stress. We report that Snell dwarf mice respond to oxidative stress induced by 3-NPA differently than their wild type littermates. This altered response results in diminished activation of the MEK-ERK kinase cascade and virtually no phosphorylation of c-Jun at Ser63 in dwarf mice after 3-NPA treatment, despite a robust phosphorylation of Ser63 in wild type mice. We propose that this altered management of oxidative stress in dwarf mice is partially responsible for the increased longevity in Snell dwarf mice.     

Rice tillering dwarf mutant dwarf3 has increased leaf longevity during darkness-induced senescence or hydrogen peroxide-induced cell death

Senescence or cell death in plant leaves is known to be inducible by darkness or H(2)O(2). When the Arabidopsis gene MAX2/ORE9 is disrupted, leaf senescence or cell death in response to the above stimuli is delayed. Because the rice (Oryza sativa L.) gene DWARF3 (D3) is orthologous to MAX2/ORE9, we wished to know whether disruption of D3 also results in increased longevity in leaves. We found that darkness-induced senescence or H(2)O(2)-induced cell death in the third leaf [as measured by chlorophyll degradation, membrane ion leakage and expression of senescence-associated genes (SAGs)] in a d3 rice mutant was delayed by 1-3 d compared to that in its reference line Shiokari. Moreover, the mRNA levels of D3, HTD1 and D10, which are orthologs of Arabidopsis MAX2/ORE9, MAX3 and MAX4, respectively, increased during cell death. These results suggest that D3 protein in rice, like MAX2/ORE9 in Arabidopsis, is involved in leaf senescence or cell death.     

水稻Dwarf1移码突变的新突变体鉴定

从一批水稻品种"中花11"组织培养苗里分离到一个矮化突变株"C6PS",它的T2代群体株高呈现3:1分离。利用该群体矮化单株与"珍汕97"、"牡丹江8"构建2个F2群体F2(CZ)、F2(CM),两个群体中高株与矮株均呈现3:1分离,证明该性状变异为单基因控制。"C6PS"表现型与已经报道的Dwarf1隐性突变体"d1"相似,以D1附近标记RM430检测F2(CZ)群体基因型,结果显示群体表型与RM430基因型呈极显著相关(P=0.0001),将该基因初步定位于Dwarf1附近。对"C6PS"及"中花11"进行D1序列分析显示,突变株中D1基因在其第九个外显子与第九个内含子的剪接位点上发生6个碱基的缺失,根据缺失两侧序列设计C6PS-D1L/R标记,在T2代群体该标记与表型呈现共分离,表明"C6PS"是一种新的Dwarf1突变体。cDNA测序显示突变体d1基因转录产物发生26个碱基的缺失,导致移码产生终止突变,从而无法翻译出有功能的Gα蛋白,因此,它是一个Gα功能缺失突变体。叶倾斜度检测显示"C6PS"对油菜素内酯响应比野生型"中花11"弱。     

水稻Dwaf1移码突变的新突变体鉴定

从一批水稻品种"中花11"组织培养苗里分离到一个矮化突变株"C6PS",它的T2代群体株高呈现3:1分离.利用该群体矮化单株与"珍汕97"."牡丹江8.,构建2个F:群体FZ(CZ).FZ(CM),两个群体中高株与矮株均呈现3:1分离,证明该性状变异为单基因控制."C6PS',表现型与已经报道的.wa叨隐性突变体"dl"相似,以DI附近标记RM430检测FZ(CZ)群体墓因型,结果显示群体表型与RM430基因型呈极显著相关(P=0.0001),将该基因初步定位于Dwarfl附近.对"C6PS',及"中花11"进行DI序列分析显示,突变株中DI墓因在其第九个外显子与第九个内含子的剪接位点上发生6个碱基的缺失,根据缺失两侧序列设计C6PS-DIL/R标记,在T:代群体该标记与表型呈现共分离,表明"C6PS"是一种新的Dwafl突变体.cDNA测序显示突变体dl基因转录产物发生26个碱基的缺失,导致移码产生终止突变,从而无法翻译出有功能的Ga蛋白,因此,它是一个Ga功能缺失突变体.叶倾斜度检测显示"C6PS",对油菜素内醋响应比野生型"中花I1"弱.