拟南芥bre突变体分析及小麦ver203F基因表达模式研究

第一部分 茎尖分生组织的中央部位是由干细胞组成，维持干细胞的动态平衡对于植物器官启动显得尤为重要。在拟南芥花序分生组织和花分生组织中分别有WUS/CLV和(WUS+LFY)/AG两个负反馈调节环控制着这一平衡，保证了花序分生组织的非决定性和花分生组织的决定性。 本文用T-DNA激活标签技术得到功能增强突变体bre，序列分析表明BRE就是干细胞特征基因WUSCHEL。定量RT-PCR表明在突变体的茎节间WUS大量表达，证实在WUS基因的调控区插入的4个35S增强子使WUS表达增强。突变体bre生长发育缓慢，茎弯曲，花器官数目改变，心皮发育加快。尤为突出的是在茎皮层直接分化出花分生组织。这些表型可能与WUS的表达增强有关。这说明WUS功能是多效的，除了在分生组织中决定干细胞命运、促进CLV和AG的表达外，还可能与生长素极性运输以及花分生组织特征基因的表达有关。 第二部分 春化作用是促进植物从营养生长向生殖生长转变的有效途径之一，作者所在实验室曾经分离到多个小麦春化相关基因。为研究春化期间它们在不同组织或不同细胞内的表达模式，首先建立并完善了RNA组织原位杂交系统。以春化相关基因ver203F为模板，采用地高辛为标记分子，借助体外转录制备RNA探针，分析了小麦胚芽和幼苗中ver203F的表达模式。结果表明：春化前和脱春化的胚芽中不表达ver203F，春化处理14天以上的胚芽幼叶表达ver203F,而且主要定位在叶的边缘分生组织细胞内，叶维管束和表皮组织未检测到转录物，胚芽鞘和茎尖分生组织中不表达。幼苗的侧芽中的幼叶有相同的表达模式。茉莉酸可以诱导ver203F的表达。．说明春化时的低温信号可能由幼叶接收，并有可能涉及到茉莉酸介导的信号转导途径。

Fatty acid composition of three species of Hypnea (Gigartinales, Rhodophyta) from Karachi coast

Hypnea musciformis (Wulf.) Lamour., H. pannosa J. Ag. and H. valentiae (Turn.) Mont., collected from the northern Arabian Sea coast of Pakistan, have been investigated for their fatty acid compositions through GC-MS. Palmitic acid was present in largest quantity (55-57%) and oleic was the major (7.6-8.4%) unsaturated fatty acid. Pentacosanoic and hexacosenoic acids are being reported for the first time from any species of Hypnea. The three species differed remarkably due to their habitat ecology.

SUB-BAND CODING TECHNIQUES FOR ROBUST 4. 8 TO 8 kb/s SPEECH CODERS.

This paper describes a speech coding technique that has been developed in order to provide a method of digitising speech at bit rates in the range 4. 8 to 8 kb/s, that is insensitive to the effects of acoustic background noise and bit errors on the digital link. The main aim has been to develop a coding scheme which provides speech quality and robustness against noise and errors that is similar to a 16000 b/s continuously variable slope delta (CVSD) coder, but which operates at half its data rate or less. A desirable aim was to keep the complexity of the coding scheme within the scope of what could reasonably be handled by current signal processing chips or by a single custom integrated circuit. Applications areas include mobile radio and small Satcomms terminals.

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring no. 8, 6– 10th April 2011

The result reported were from a monitoring survey no.8 undertaken between 6th and 10th April 2011 during construction period of the Bujagali Hydropwer Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far,durin construction phase of the project, seven monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009,October 2009, April 2010, September 2010 and the present one, in April 2011. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: Water quality determinants Biology and ecology of fishes and food webs Fish stock and fish catch including economic aspects of catch and Sanitation/vector studies (bilharzias and river blindness)