Mapping of leaf and neck blast resistance genes with resistance gene analog, RAPD and RFLP in rice

An F₈ recombinant inbred population was constructed using a commercial indica rice variety Zhong 156 as the female parent and a semidwarf indica variety Gumei 2 with durable resistance to rice blast as the male parent. Zhong 156 is resistant to the fungus race ZC₁₅ at the seedling stage but susceptible to the same race at the flowering stage. Gumei 2 is resistant to ZC₁₅ at both stages. The blast resistance of 148 recombinant inbred lines was evaluated using the blast race ZC₁₅. Genetic analysis indicated that the resistance to leaf blast was controlled by three genes and the presence of resistant alleles at any loci would result in resistance. One of the three genes did not have effects at the flowering stage. Two genes, tentatively assigned as Pi24(t) and Pi25(t), were mapped onto chromosome 12 and 6,respectively, based on RGA (resistance gene analog), RFLP and RAPD markers. Pi24(t) conferred resistance to leaf blast only, and its resistance allele was from Zhong 156. Pi25(t) conferred resistance to both leaf and neck blast, and its resistance allele was from Gumei 2. In a natural infection test in a blast hot-spot, Pi25(t) exhibited high resistance to neck blast, while Pi24(t) showed little effect. This revised version was published online in August 2006 with corrections to the Cover Date.     

水稻抗稻瘟病鉴定中的几个相关问题的探讨

 利用CO39近等基因系及其累加系和4个稻瘟病菌的原始菌株及其突变体,研究稻瘟病抗性鉴定中经常考虑的几个因子。结果表明,接种孢子量与植株的病级、病斑数和发病叶面积呈正相关,品种对混合菌株接种的抗病性主要取决于致病性强的菌株,弱菌株的诱导抗性有限,过量施用氮肥可使部分抗病品种感病,被克服的主效基因没有明显的残效抗性。     

IR64品种内残余变异的来源和遗传模式

 用SSR标记对个体间表型一致的籼稻IR64（由育种家提供的种子，简称S0）品种内的残余遗传变异的来源以及变异的遗传模式进行了研究。发现第2染色体短臂上存在残余变异，该变异区间包含5个SSR座位，大小约为30 cM。进一步研究显示，变异存在于1989年种质库保存的IR64种子中，而变异的根源为IR64的原始亲本（母本IR5657 33 2为1990年的库存，父本为1979年的库存）。S0中存在的变异均能在亲本中检测到。另外，对S0连续套袋自交后代分析表明残余变异以孟德尔方式稳定遗传。验证了在自花授粉作物中，推广品种内的残余变异源于亲本，对种子纯度鉴定、品种指纹图谱的构建、种质资源的保存具有借鉴意义。     

Nutritional Assessment of Some Traditionally Processed Hill-Stream Fishes of Manipur with Special Reference to n-3 Fatty Acids

Traditionally, smoke-dried hill-stream fishes are an important part of the diet of the people of Manipur, India. The nutritional values of the processed fishes were studied. The proximate composition, protein digestibility, and fatty acid composition of hill-stream fishes Neolissochilus stracheyi, Labeo pangusia, Semiplotus manipurensis, Schizothorax sp., and Ompok sp. were determined. The mean values of protein, lipid, ash, and moisture ranged from 31.20 to 72.58%, 6.36 to 18.73%, 4.32 to 5.33%, and 10.14 to 16.25%, respectively. The protein digestibilities were high (75.56–97.65%), and alpha amino nitrogen liberated during in vitro tests was highest (19.34 mg/g) in L. pangusia in pepsin and trypsin phase. The n-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid were highest in L. pangusia, followed by S. manipurensis. The study shows that the processed hill-stream fishes have different food values, and some are a good source of highly digestible protein and also contain a good amount of essential fatty acids that may be beneficial for brain development and optimal health.     

Growth and blood chemistry of Atlantic halibut (<Emphasis Type="Italic">Hippoglossus hippoglossus</Emphasis> L.) in relation to salinity and continuous light

In order to study the possible interactive effects of salinity and photoperiod on growth, feed conversion, and blood chemistry in juvenile halibut, 2,604 (initial mean weight 26.8 g ± 0.2 SEM) juvenile halibut were exposed to six different combinations of salinities (13, 21, or 27‰) and photoperiods [continuous light, C and simulated natural photoperiod (65°N), SNP] for 129 days. Improved (10–20%) growth and 10–24% higher feed conversion efficiency were observed at low and intermediate salinities compared to the high salinity groups. Improved feed conversion efficiency (20%) and temporary growth enhancing effects (10%) of continuous light were observed, but effects faded out as day length in the simulated natural photoperiod group increased. No interactive effects of photoperiod and salinity on growth feed conversion or measured blood chemistry variables (blood sodium, pH level, haematocrit, bicarbonate content, and total carbon dioxide). It is suggested that juvenile Atlantic halibut should be reared at low and intermediate salinities and at continuous light, as this will improve growth and increase feed conversion efficiency.     

间作条件下玉米根系固土力原位测定

农作物的根系对土壤的固持作用可以减少坡耕地的水土流失。本研究以云南主要农作物玉米为例,通过采用剪切箱和锚杆拉力计,在玉米的成熟期对单作和与大豆间作2 种种植方式下的玉米根系在10 cm 深度上的固土能力进行了原位测定。结果表明,当施加载荷为1.5 kN 时单作玉米根系位移为5.9 mm,与大豆间作下的玉米根系位移是3.15 mm,裸地的位移是7.26 mm。单作玉米根系滑动距离要明显高于间作玉米根系,说明间作种植模式下的玉米的固持土壤能力要强于单作玉米。     

Effects of rosiglitazone,a PPARγ ligand,on chemoprevention of MNNG-induced gastric cancer in rats

AIM: To examine the chemo-preventive effects of peroxisome proliferator-activated receptor γ(PPARγ) ligand rosiglitazone (RSG) on a rat model of gastric carcinogenesis induced by chemical carcinogen N-methyl-N’-nitro-N-nitrosoguanidine (MNNG). We also attempted to identify novel anti-cancer mechanisms of rosiglitazone.METHODS: Ninety male Wistar rats were randomly allocated into six groups: group A (control group); group B (MNNG group); group C, D and E (RSG group, given different concentrations of rosiglitazone). The treatment procedures were terminated at 40th week. Stomach was harvested and gastric carcinoma was verified by histology. The gastric cancer incidence in different groups was calculated. To elucidate the mechanisms underlying the chemo-preventive effects of PPARγ ligand, we examine the gene expression profiles of MNNG induced gastric cancer and the rosiglitazone treated gastric cancer with Uniset Rat I Bioarray microarray.RESULTS: Incidence of gastric cancer in group A-E was 0% (0/10), 70% (14/20), 15% (3/20), 30% (6/20) and 30% (6/20), respectively. Gastric cancer incidence in group C, D and E was significantly lower than that in group B (P<0.01). A gene that showed prominent responses in rosiglitazone treated group was identified. The hypertension-related, calcium-regulated gene (HCaRG) was significantly upregulated in rat gastric carcinoma in rosiglitazone treated group when compared to MNNG group. The expression of HCaRG was down-regulated in human gastric cancerous tissue. CONCLUSION: PPARγ ligand rosiglitazone has a potent chemo-preventive effect against gastric cancer development in rats. Upregulation of HCaRG may be one of the mechanisms underlying the chemo-preventive effect of rosiglitazone in gastric cancer.     

Essay of Different Extraction Procedures in Capelin Fish Meal for Biogenic Amine Determination by HPLC

This study assesses the effects of different extraction procedures of biogenic amines in capelin fish meal with different concentrations of trichloroacetic acid (TCA) for their determination by high performance liquid chromatography (HPLC). No significant differences were noted between the use of TCA at 7.5 and 10% for the extraction of biogenic amines in E1 and E3 extraction, except for tyramine. The extraction using 7.5% TCA in one step and centrifugation (E1) was a simple and rapid method. This extraction seems to be the most suitable for the extraction of amines in these kinds of samples, compared to the other methods tested. The biogenic amine that presented the highest levels in the fish meal studied was cadaverine (208–226 mg/kg), followed by putrescine and histamine (164–173 and 44–46 mg/kg, respectively). Biogenic amine levels were low when compared to the toxic levels observed in these kinds of products.