Genetic mapping studies of 40 loci and 23 cosmids in chromosome 11p13-11g13, and exclusion of μ-calpain as the multiple endocrine neoplasia type 1 gene

Forty loci (16 polymorphic and 24 non-polymorphic) together with 23 cosmids isolated from a chromosome 11-specific library were used to construct a detailed genetic map of 11p13-11g13. The map was constructed by using a panel of 13 somatic cell hybrids that sub-divided this region into 19 intervals, a meiotic mapping panel of 33 multiple endocrine neoplasia type 1 (MEN1) families (134 affected and 269 unaffected members) and a mitotic mapping panel that was used to identify loss of heterozygosity in 38 MENI-associated tumours. The results defined the most likely order of the 16 loci as being: 11pter-D11S871(D11S288, D11S149)-11cen-CNTF-PGA-ROM1-D11S480-PYGM-SEA-D11S913-D115970-D11S97-D11S146-INT2-D11S971-D11S533-11gter. The meiotic mapping studies indicated that the most likely location of the MEN1 gene was in the interval flanked by PYGM and D11S97, and the results of mitotic mapping suggested a possible location of the MEN1 gene telomeric to SEA. Mapping studies of the gene encoding μ-calpain (CAPN1) located CAPN1 to llg13 and in the vicinity of the MEN1 locus. However, mutational analysis studies did not detect any germ-line CAPN1 DNA sequence abnormalities in 47 unrelated MEN1 patients and the results therefore exclude CAPN1 as the MEN1 gene. The detailed genetic map that has been constructed of the 11p13-11g13 region should facilitate the construction of a physical map and the identification of candidate genes for disease loci mapped to this region.     

Tobacco (Nicotiana tobaccum) nuclear transgenics with high copy number can express NPTII driven by the chloroplast psbA promoter

A chloroplast expression vector containing the NPTII gene under the control of apsbA promoter (psbA-NPTII) was constructed, and was biolistically delivered into both suspension cells and leaf strips of tobacco (Nicotiana tabaccum). Analyses of subsequently recovered kanamycin-resistant transgenic plants indicate that the psbA-NPTII gene was not located in the chloroplast, but was in the nucleus in very high copy number. This conclusion was based upon results from: (1) Southern hybridization analyses of chloroplast and nuclear DNAs using NPTII, chloroplast-marker, and nuclear-marker probes; (2) pulse-field gel electrophoresis; and (3) kanamycin screening of sexual progenies. This study suggests that the nuclear expression of the NPTII gene may have been associated with many copies of the psbA-NPTII construction. Very high copy number in the nucleus might either allow NPTII expression from the otherwise inadequate psbA promoter, or might increase the chance of recombining with upstream tobacco regulatory sequences.     

The genetics of blackleg [Leptosphaeria maculans (Desm.) Ces. et De Not.] resistance in rapeseed (Brassica napus L.)

The genetic control of adult-plant blackleg [Leptosphaeria maculans (Desm.) Ces. et De Not.] resistance in rapeseed (Brassica napus L.) was studied in the F₂ and first-backcross populations of the cross Maluka (blackleg-resistant) x Niklas (highly susceptible). A L. maculans isolate possessing high levels of host specificity (MB2) was used in all inoculations. Resistance/susceptibility was evaluated using three separate measures of crown-canker size, i.e. the percentage of crown girdled (%G), external lesion length (E) and internal lesion area (%II). Disease severity scores for the F₂ and first-backcross populations based on E and %II gave discontinuous distributions, indicating major-gene control for these measures of resistance; but those for %G were continuous, indicating quantitative genetic control for this measure. Chi-square tests performed on the (poorly-defined) resistance classes, based on E, in the F₂ and first-backcross populations indicated the likelihood for resistance being governed by a single, incompletely dominant major gene. Although the distributions of the F₂ and first-backcross populations, based on%II, were clearly discontinuous, the observed segregation ratios for resistance and susceptibility did not fit any of the numerous Mendelian ratios which were considered. Differences in inheritance of resistance according to the assessment method and blackleg isolate used, were discussed.     

野生紫斑牡丹和四川牡丹种子萌发特性及与其致濒的关系

野生牡丹种子一般较小,而且不同产地之间形状、大小差异较大。其萌发特性与栽培牡丹相比也有较大差异：萌发期长达半年以上,且萌发温度在１０～１５℃为宜,超过２０℃则明显不利于生根及上胚轴生长。四个不同分布地的四川牡丹种子萌发率较一致,均在６０～７７％之间。三个不同产地的紫斑牡丹种子萌发率则相差甚远,分布于甘肃文县的萌发率达７６％,而分布于陕西略阳和湖北神农架的萌发率则分别只有１２％和４．４％,出苗率则更低。本文认为紫斑牡丹的种子特性是其在自然界处于濒危状态的重要原因之一。     

不同生境区稻田节肢动物群落相似性分析

根据不同生境区稻田节肢动物群落系统调查结果,应用组平均聚类分析法及主成分分析法,讨论节肢动物群落的相似（相异）性问题。结果表明：生境条件及管理措施的差异对群落的结构影响较为明显,不同生境区的稻田节肢动物群落,都能在一定距离取值时聚合成一类,而水稻品种对此影响较小。主成分分析结果由二维图表达已基本满足要求。结果说明大八镇生境区稻田节肢动物群落与岗列镇生境区稻田节肢动物群落差异较大,分别列于两个极端。海陵镇生境区稻田介于两者之间,而与岗列镇生境区稻田节肢动物群落重叠。与聚类分析结果有所差异。这可能与主成分分析法损失部分信息有关。     

Lck-dependent tyrosyl phosphorylation of the phosphotyrosine phosphatase SH-PTP1 in murine T cells.

The phosphorylation and dephosphorylation of proteins on tyrosyl residues are key regulatory mechanisms in T-cell signal transduction and are controlled by the opposing activities of protein tyrosine kinases and phosphotyrosyl phosphatases (PTPs). In T cells, several nontransmembrane protein tyrosine kinases are associated with receptors; for example, Lck is bound to the coreceptors CD4 and CD8 and becomes activated upon their stimulation. In comparison, little is known about the role of nontransmembrane PTPs in early T-cell signaling. SH-PTP1 (PTP1C, HCP, SHP) is a nontransmembrane PTP expressed primarily in hematopoietic cells, including T cells. We have found that SH-PTP1 is basally phosphorylated on serine in resting T cells. Upon stimulation of CD4 or CD8 either in a T-cell hybridoma cell line or in primary thymocytes, SH-PTP1 becomes tyrosyl phosphorylated. Moreover, SH-PTP1 is constitutively phosphorylated on tyrosine in the Lck-overexpressing lymphoma cell line LSTRA. SH-PTP1 is also a good substrate for recombinant Lck in vitro. Comparisons of the tryptic phosphopeptide maps of wild-type SH-PTP1 and deletion and point mutations establish that the two sites (Y-536 and Y-564) which are directly phosphorylated by Lck in vitro are also phosphorylated in vivo in LSTRA cells. One of these sites (Y-564) is phosphorylated in T cells in response to Lck activation. We conclude that SH-PTP1 undergoes Lck-dependent tyrosyl phosphorylation in T cells and likely plays a role in early T-cell signaling.     

Metabolic activation of unsaturated derivatives of valproic acid. Identification of novel glutathione adducts formed through coenzyme A-dependent and -independent processes

The ability of 2-n-propyl-4-pentenoic acid (Δ⁴-VPA) and 2-n-propyl-2(E)-pentenoic acid ([E]-Δ²-VPA), two unsaturated metabolites of valproic acid (VPA), to form reactive intermediates, deplete hepatic glutathione (GSH) and cause accumulation of liver triglycerides was investigated in the rat. With the aid of ionspray liquid chromatography-tandem mass spectrometry (LC-MS/MS), three GSH adducts were detected in the bile of Δ⁴-VPA-treated animals and were identified as 4-hydroxy-5-glutathion-S-yl-VPA-γ-lactone, 5-glutathion-S-yl-(E)-Δ³-VPA and 3-oxo-5-glutathion-S-yl-VPA. A fourth conjugate was identified tentatively as 4-glutathion-S-yl-5-hydroxy-VPA. Quantitative analysis of the corresponding N-acetylcysteine (NAC) conjugates in urine indicated that metabolism of Δ⁴-VPA via the GSH-dependent pathways accounted for approximately 20% of an acute dose (100 mg kg⁻¹ i.p.). In contrast, when rats were given an equivalent dose of (E)-Δ²-VPA, only one GSH adduct (5-glutathion-S-yl-(E)-Δ³-VPA) was detected at low concentrations in bile. In vitro experiments with rat liver mitochondria demonstrated that Δ⁴-VPA undergoes coenzyme A- and ATP-dependent metabolic activation in this organelle via the β-oxidation pathway to intermediates which bind covalently to proteins. When liver homogenates and hepatic mitochondria from rats injected with Δ⁴-VPA, (E)-Δ²-VPA or VPA were analyzed for GSH content, it was found that only Δ⁴-VPA depleted GSH pools significantly. Treatment of rats with Δ⁴-VPA and (to a lesser extent) VPA led to an accumulation of liver triglycerides, whereas (E)-Δ²-VPA had no measurable effect. It is concluded that Δ⁴-VPA undergoes metabolic activation by both microsomal cytochrome P-450-dependent and mitochondrial coenzyme A-dependent processes, and that the resulting electrophilic intermediates, which are trapped in part by GSH, may mediate the hepatotoxic effects of this compound. In contrast, (E)-Δ²-VPA is not transformed to any appreciable extent to reactive metabolites, which thus accounts for the apparent lack of hepatotoxicity of this positional isomer in the rat.     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。