六个虹鳟代表性繁育群体肌肉营养成分分析

研究主要通过分析虹鳟(Oncorhynchus mykiss)不同繁育群体间肌肉品质和营养成分的种质特性,为虹鳟遗传资源的保护利用、优良性状的筛选及新品种选育提供基础数据资料。采用凯氏定氮、索氏抽提和水解氨基酸等现行国家标准测定肌肉中的营养成分、氨基酸和脂肪酸的含量,对国内6个不同地区虹鳟代表性繁育群体进行肌肉营养成分和品质的系统分析和评价。结果表明,各繁育群体水分含量(66.50%—77.00%)、灰分含量(1.12%—1.43%)、粗蛋白含量(19.00%—21.84%)和粗脂肪含量(2.04%—9.08%)有显著差异(P<0.05);17种氨基酸总量(TAA)为15.27%—18.90%,各群体氨基酸指数(AAS)、化学指数(CS)和必需氨基酸指数(EAAI)均高于联合国粮食及农业组织(Food and Agriculture Organization, FAO)标准; 23种脂肪酸中包括8种饱和脂肪酸(SFA)、4种单不饱和脂肪酸(MUFA)和11种多不饱和脂肪酸(PUFA),其含量分别为17.81%—31.75%、27.86%—30.35%和40.25%—54.32%,...     

四个不同地理鲇群体肌肉营养组成的比较分析

为了丰富黄河、松花江和大洋河鲇的肌肉营养数据, 试验采用国家标准方法对4个自然河段鲇群体(黄河白银段BY、黄河郑州段ZZ、松花江哈尔滨段HEB和大洋河东港段DG)背部肌肉的营养组成进行测定。结果表明, BY群体粗蛋白显著(P0.05)高于ZZ和DG两群体, BY群体粗脂肪显著(P0.05)高于ZZ、DG和HEB三群体。四群体脂肪酸组成以不饱和脂肪酸为主, 单不饱和脂肪酸中油酸含量最高, BY群体油酸含量显著(P0.05)高于ZZ、DG和HEB三群体, BY群体EPA+DHA含量最低, 和ZZ、DG和HEB三群体有显著(P0.05)差异。四群体氨基酸组成均以谷氨酸含量最高。除缬氨酸和异亮氨酸外, 四群体其余氨基酸评分(AAS)均接近或大于1; 四群体各氨基酸的化学评分(CS)均大于0.5。缬氨酸为第一限制性氨基酸, 异亮氨酸为第二限制性氨基酸。必需氨基酸指数(EAAI), HEB群体最高, DG群体最低。该结果说明, BY群体与ZZ、DG和HEB三群体营养价值差别大, ZZ、DG和HEB三群体间营养价值接近。四群体的营养差异可能由不同地理环境导致。     

6个地区青海湖裸鲤肌肉营养成分分析

采用常规生化分析方法,测定青海湖6个不同地区的青海湖裸鲤(Gymnocypris przew alskii)肌肉主要营养成分,对其营养价值进行评价。结果表明,淡水青海湖裸鲤肌肉中脂肪含量显著大于(P<0.05)其他5个地区,蛋白含量显著大于(P<0.05)黑马河青海湖裸鲤肌肉的蛋白含量,6个地区青海湖裸鲤肌肉营养成分存在一定的地区差异。总体上,青海湖裸鲤肌肉(鲜样)中粗蛋白含量为17.26%~18.87%;粗脂肪含量为1.51%~3.37%;灰分含量为1.42%~1.61%;18种氨基酸总量15.48%~17.16%,其中除色氨酸外7种人体必需氨基酸总量6.38%~7.05%,4种鲜味氨基酸总量5.82%~6.49%。青海湖裸鲤肌肉中蛋白质含量较高,氨基酸种类齐全,必需氨基酸与鲜味氨基酸含量较高,尤其是淡水青海湖裸鲤品质更佳,淡水的生态环境可能更适合青海湖裸鲤的生长。     

虹鳟(♀)×山女鳟(♂)杂交F1及其亲本肌肉营养成分和肌肉质地的比较

以虹鳟(Oncorhynchus mykiss)、山女鳟(O.masou masou)及其杂交F1(虹鳟♀×山女鳟♂)为研究对象,分别进行了肌肉营养成分和肌肉质地测定.结果显示,(1)杂交F1肌肉粗脂肪含量显著低于双亲(P＜0.05),含水率和粗蛋白含量介于双亲之间,其中含水率最高者为山女鳟,粗蛋白含量最高者为虹鳟,并且三者间差异显著(P＜0.05);(2)杂交F1肌肉氨基酸总量、必需氨基酸总量、非必需氨基酸总量和鲜味氨基酸总量均显著高于双亲(P＜0.05),其半必需氨基酸含量高于虹鳟,但低于山女鳟;(3)3种鱼肌肉营养品质评价结果表明,杂交F1肌肉必需氨基酸指数(77.77)明显高于虹鳟(63.67),略低于山女鳟(79.19);(4)杂交F1肌肉肉色(亮度、红度、黄度)和嫩度与双亲相比差异显著(P＜0.05),按肉色和嫩度测定值由高到低排列依次为山女鳟＞杂交F1＞虹鳟.研究结果表明,杂交Fl继承了山女鳟肉质优良的特性,肌肉品质优于虹鳟,这为虹鳟和山女鳟杂交育种提供了参考.     

3种鲳属鱼不同组织脂肪酸组成的比较研究

3种野生鲳属鱼银鲳(Pampus argenteus)、灰鲳(Pampus cinereus)和中国鲳(Pampus sinensis)样本于2010年3—4月采集于浙江东海海域,用GC/MS法分别对其肝脏和肌肉的总脂和脂肪酸组成进行了分析和评价,同时比较了野生和养殖银鲳的脂肪酸组成。结果表明:3种鲳鱼肝脏总脂平均值(19.95%)显著高于肌肉总脂平均值(11.69%)(P<0.05),灰鲳肝脏和肌肉中的总脂含量显著高于银鲳和中国鲳(P中国鲳>灰鲳;肝脏的脂肪酸种类组成较丰富,MUFA含量中国鲳>银鲳>灰鲳(P<0.05),多不饱和脂肪酸(PUFA)含量灰鲳>银鲳>中国鲳(P<0.05);肌肉中MUFA含量银鲳>灰鲳>中国鲳(P<0.05),PUFA含量3种鲳鱼无显著差异(P>0.05)。EPA+DHA含量在3种鲳鱼肌肉中无显著差异(P>0.05),但在中国鲳肝脏未检测到EPA,在灰鲳肝脏和中国鲳肝脏和肌肉中未检测到DHA,而在银鲳肝脏和肌肉组织中EPA和DHA均有分布,DHA含量分别达到13.99%和15.95%;野生银鲳的油酸、EPA和DHA含量显著高于养殖银鲳,PUFA含量是养殖银鲳的1.53倍。由实验结果及与其它经济鱼类相比可知,3种鲳属鱼主要是以不饱和脂肪酸为主,在2种组织中平均占53.89%,EPA+DHA含量平均占PUFA的82.54%,这3种鲳鱼具有很高的营养价值并且银鲳更胜一筹,同时野生银鲳品质优于养殖银鲳,但不失为一种优良的养殖品种。     

不同年龄段养殖宽体沙鳅肌肉营养成分分析与评价

采用国家标准方法对1、2、3龄宽体沙鳅养殖群体的肌肉营养成分及品质进行了分析比较。结果显示: (1)各年龄组宽体沙鳅肌肉粗蛋白质和粗脂肪含量较高且随着年龄的增长呈增长趋势。其中, 粗蛋白在2龄和3龄组增长不显著(P>0.05), 粗脂肪增长显著(P<0.05)。(2)各年龄组肌肉氨基酸组成相同, 均以鲜味特征氨基酸谷氨酸含量最高, 其次为天门冬氨酸; 第一限制性氨基酸均为缬氨酸; 支链氨基酸与芳香族氨基酸的比值(F值)分别为2.22、2.08和2.12。(3)各年龄组宽体沙鳅脂肪酸在组成和含量上略有差异, 表现为不饱和脂肪酸含量高于饱和脂肪酸含量(P<0.05); 不饱和脂肪酸中单不饱和脂肪酸含量较高(P<0.05); 多不饱和脂肪酸(PUFA)在2龄组最高(P<0.05)且EPA+DHA含量随年龄的增长递增(P<0.05)。综上, 各年龄段宽体沙鳅肌肉营养丰富, 味道鲜美, 以2龄鱼体营养质量最优。     

中华鳖4个品系营养成分分析与比较

为了解墨鳖的营养价值, 对墨鳖、野生中华鳖、淮河鳖和日本鳖肌肉的一般营养成分、氨基酸含量、脂肪酸含量及裙边胶原蛋白进行测定和比较。结果显示: (1) 4个品系鳖肌肉水分含量分别为80.84%、79.48%、81.57%和79.25%, 墨鳖显著高于野生鳖和日本鳖(P<0.05); 粗蛋白含量分别是17.82%、17.60%、15.93%和16.40%, 墨鳖含量最高, 显著高于淮河鳖和日本鳖(P<0.05); 粗脂肪含量分别是0.42%、1.43%、0.65%和1.06%, 墨鳖显著低于其他鳖(P<0.05); 4个品系鳖灰分含量差异不显著(P>0.05)。(2) 4个品系鳖肌肉中总氨基酸和呈味氨基酸含量均以墨鳖最高。(3)4个品系鳖不饱和脂肪酸含量分别为65.19%、56.44%、59.32%和54.73%, 墨鳖显著高于其他鳖(P<0.05), 其中墨鳖单不饱和脂肪酸含量显著低于野生鳖(P<0.05), 多不饱和脂肪酸含量显著高于其他3个品系(P<0.05); 饱和脂肪酸含量分别为32.50%、41.85%、39.41%和39.98%, 墨鳖显著低于其他鳖(P<0.05)。(4)墨鳖肌肉中DHA和EPA含量与野生鳖差异不显著(P>0.05), 显著高于淮河鳖和日本鳖(P<0.05), 花生四烯酸(AA)含量显著高于其他3个品系鳖(P<0.05)。(5) 4个品系鳖裙边胶原蛋白含量均较高, 为160.6—170.4 mg/g。结果表明墨鳖是一种营养价值高、肉味鲜美的地方品系。     

海、淡水养殖日本鳗鲡肌肉和鱼皮营养分析比较

为了比较海、淡水养殖日本鳗鲡(Anguilla japonica)肌肉和鱼皮营养成分差异, 采用生物化学方法对海水与淡水养殖日本鳗鲡肌肉和鱼皮的一般营养成分、氨基酸含量、脂肪酸含量和矿物质含量进行测定与分析。结果显示, 海、淡水养殖日本鳗鲡鱼皮的水分、粗蛋白和灰分含量均显著性低于肌肉(P0.05), 但鱼皮粗脂肪含量显著高于肌肉(P0.05)。淡水养殖日本鳗鲡肌肉的粗蛋白含量显著性高于海水养殖日本鳗鲡(P0.05)。海、淡水养殖日本鳗鲡肌肉总氨基酸含量分别为50.22%和54.10%, 鱼皮总氨基酸含量分别为42.56%和45.80%。海、淡水养殖日本鳗鲡鱼皮呈鲜味氨基酸占氨基酸总量显著性高于肌肉(P0.05)。海、淡水养殖日本鳗鲡肌肉和鱼皮均以不饱和脂肪酸为主(65.96%67.51%), 并以单不饱和脂肪酸C18: 1n9含量为主(38.64%44.79%)。海水养殖日本鳗鲡肌肉矿物质元素(Fe、Ca、Cu、Na)和鱼皮矿物质元素(Fe、Mn、Na)的平均含量均显著高于淡水养殖日本鳗鲡(P0.05), 但Zn含量显著低于淡水养殖日本鳗鲡(P0.05)。研究表明, 不同养殖环境的日本鳗鲡肌肉和鱼皮营养成分丰富, 淡水养殖日本鳗鲡肌肉和鱼皮的氨基酸含量和脂肪酸组成方面稍优于海水养殖日本鳗鲡, 而海水养殖环境日本鳗鲡肌肉和鱼皮的矿物质元素含量得到较高的富集。       

菊黄东方鲀、暗纹东方鲀及其杂交F1代肌肉营养成分的比较分析

为了了解菊黄东方鲀(Takifugu flavidus)、暗纹东方鲀(T.obscurus)及其杂交F1代的肌肉营养特征,利用生物化学方法,从每类实验样本中取9尾对其肌肉中的粗蛋白、粗脂肪、水分、粗灰分和氨基酸成分进行了测定和分析。结果显示:(1)杂交F1代在生长方面具有明显的杂交优势,与亲本之间存在着显著差异(P0.05),杂交F1代的体重为其亲本的1.48~1.77倍;(2)杂交F1代肌肉水分含量与其母本含量相近,但粗脂肪含量均较亲本少(P0.05),粗蛋白含量则与亲本差异不显著(P0.05);(3)除色氨酸和胱氨酸外,16种氨基酸均在肌肉样本中被检测到,除甲硫氨酸外,其余15种氨基酸间含量均存在着显著性差异(P0.05)。菊黄东方鲀(♀)×暗纹东方鲀(♂)杂交F1代的总氨基酸含量最高,而暗纹东方鲀(♀)×菊黄东方鲀(♂)F1代总氨基酸含量则介于两亲本之间。对其必需氨基酸总量进行分析发现,菊黄东方鲀与其正反杂交F1代之间均存在显著性差异(P0.05),而暗纹东方鲀与其正反杂交F1代之间差异不显著(P0.05);(4)肌肉营养品质评价结果表明,菊黄东方鲀(♀)×暗纹东方鲀(♂)杂交F1代的鲜味氨基酸含量为26.68%,明显高于双亲样本(菊黄东方鲀22.28%、暗纹东方鲀25.20%),而暗纹东方鲀(♀)×菊黄东方鲀(♂)F1代的鲜味氨基酸总量(23.30%)较其父本偏高,但低于其母本。研究结果表明,杂交东方鲀的肌肉营养综合了双亲的优良特性,特别是是菊黄东方鲀(♀)×暗纹东方鲀(♂)杂交F1代,拥有最高的鲜味氨基酸含量,具有推广价值。     

刺猬肌肉营养成份分析

对刺猬肌肉营养成分测定及其氨基酸分析,评价其营养价值。结果表明,刺猬肌肉(鲜样)中粗蛋白含量丰富(20.92±0.14)%,肌肉中含18种氨基酸,占肌肉总量的80.13%(干样百分比),其中人体必需氨基酸8种,占氨基酸总量的46.88%,必需氨基酸指数(EAAI)为64.58,氨基酸构成比例符合FAO/WHO标准;鲜味氨基酸总量为30.82%;钙和铁的含量分别为33.8mg/100g和11.0mg/100g。说明其具有较高的营养和食用价值。     

我国水稻条纹病毒RNA3片段序列分析—纤细病毒属重配的又一证据

测定了来源于我国水稻条纹叶枯病常年流行区的辽宁盘锦 (PJ)、云南昆明 (KM)、云南宜良 (YL)及病害暴发区的江苏洪泽 (HZ)的水稻条纹病毒 (RSV) 4个分离物RNA3全长序列 ,其长度分别为 2 480bp、2 5 0 9bp、2 489bp和 2 497bp。与已报道的RSV云南Y、日本T和M分离物RNA3序列进行比较的结果表明 ,这 7个分离物可分为两组 ,其中 ,KM、YL分离物为一组 ,PJ、HZ、Y、T和M分离物为另一组。组与组之间 ,RNA3的毒义链 (vRNA3)及RNA3的毒义互补链 (vcRNA3)上的ORF的核苷酸同源性分别为 97%～ 98%和 93%～ 94% ,但在氨基酸水平上则没有明显差异。结合上述RSV分离物RNA4的核苷酸全序列比较结果 ,推测认为RSV自然种群中存在两个与地理因素相关的不同类型的亚群 ,Y分离物不同片段具有不同来源可能是由重配引起的。     

Exercise training combined with antioxidant supplementation prevents the antiproliferative activity of their single treatment in prostate cancer through inhibition of redox adaptation

In preclinical models, exercise training (ET) or pomegranate juice (PJ) prevents prostate cancer progression. Here, we hypothesized that physical exercise combined with antioxidants could induce synergistic effects through oxidative stress modulation. Forty male Copenhagen rats with prostate tumors were divided into four groups: control, PJ, ET, and PJ+ET. Rats from the PJ group consumed 750 µl of PJ daily, rats from the ET group ran on a treadmill 5 days per week, and PJ+ET rats received the combined treatment. Each week, tumor growth was evaluated. After 4 weeks of treatment, the rats were euthanized and blood, muscles, and tumors were collected. Tumor Ki67, extracellular signal-regulated kinase (ERK) activation, Bcl-2 expression, and enzymatic and nonenzymatic antioxidant defenses, as well as oxidative stress markers (oxidized base, lipid peroxidation, protein carbonylation), were measured. PJ or ET significantly decreased prostate tumor proliferation (Ki67 staining, p<0.05) through the modulation of ERK phosphorylation, whereas the combination of treatments did not limit cancer progression. PJ significantly reduced Bcl-2 expression in tumors (p<0.05) and the combination of PJ and ET prevented this effect. PJ or ET increased enzymatic antioxidant defenses in muscle, PJ increased nonenzymatic antioxidant defenses in plasma and whole blood. In addition, PJ reduced TBARS and 8-oxodGuo levels in tumors as well as ET (p<0.05), whereas protein carbonyl levels were not affected by these two strategies. Paradoxically, association of PJ+ET did not increase antioxidant defenses and no reduction in oxidative stress markers was induced. Loading cancer cells with antioxidants blunts the positive effects of ET and interferes with important reactive oxygen species-mediated physiological processes such as antioxidant adaptations.     

不同年龄段前列腺外周带基质细胞超微结构差异

目的:研究不同年龄段前列腺外周带基质细胞超微结构并探讨其意义。方法:透射电镜观察3例年轻组(23-、26-、32-岁)和3例老年组(56-、64-、71-岁)正常前列腺外周带和3例前列腺癌组织的超微结构。Masson’s Trichrome染色法观察前列腺外周带基质胶原的分布情况。结果:年轻组、老年组前列腺外周带间质均以平滑肌细胞分布为主,间杂成纤维细胞,但老年组平滑肌细胞和成纤维细胞体积较大、形态不规则。与正常年轻组相比,老年组前列腺外周带成纤维细胞存在明显老化和肌化改变,部分细胞内与蛋白合成相关的细胞器粗面内质网发达,呈现肌成纤维细胞特征。与年轻组和老年组外周带相比,前列腺癌基质中功能更加活跃的肌成纤维细胞和胶原蛋白数量增加明显。Masson’s Trichrome染色支持超微观察到的基质胶原分布差异:年轻组<老年组<前列腺癌组。结论:不同年龄段前列腺外周带基质细胞超微结构间存在差异,老年组前列腺外周带和前列腺癌基质组织中具有活性的肌成纤维细胞的增加可能是造成老年前列腺癌高发和恶性进展的重要病理基础之一。     

Pomegranate juice protects nitric oxide against oxidative destruction and enhances the biological actions of nitric oxide.

Pomegranate juice (PJ), which is a rich source of potent flavonoid antioxidants, was tested for its capacity to protect nitric oxide (NO) against oxidative destruction and enhance the biological actions of NO. Employing chemiluminescence headspace analysis, PJ was found to be a potent inhibitor of superoxide anion-mediated disappearance of NO. PJ was much more potent than Concord grape juice, blueberry juice, red wine, ascorbic acid, and DL-alpha-tocopherol. As little as 3 microl of a 6-fold dilution of PJ, in a reaction volume of 5000 microl, produced a marked antioxidant effect, whereas 300 microl of undiluted blueberry juice or nearly 1000 microl of undiluted Concord grape juice were required to produce similar effects. PJ and other antioxidant-containing products were found to augment the anti-proliferative action of NO (DETA/NO) on vascular smooth muscle cell (rat aorta) proliferation. PJ was much more effective than the other products tested and elicited no effects when tested alone in the absence of added NO. Similarly, neither PJ nor the other products enhanced the anti-proliferative action of alpha-difluoromethylornithine, a stable substance that inhibits cell growth by NO-independent mechanisms. In order to determine whether PJ is capable of increasing the production of NO by vascular endothelial cells, PJ was tested for its capacity to upregulate and/or activate endothelial NO synthase (eNOS) in bovine pulmonary artery endothelial cells. PJ elicited no effects on eNOS protein expression or catalytic activity. Moreover, PJ did not enhance promoter activity in the eNOS gene (COS-7 cells transfected with eNOS). These observations indicate that PJ possesses potent antioxidant activity that results in marked protection of NO against oxidative destruction, thereby resulting in augmentation of the biological actions of NO.     

Genetic structure and gene flow of Anopheles minimus and Anopheles harrisoni in Kanchanaburi Province, Thailand

Isozyme frequencies were compared in seven field collections of Anopheles minimus complex using starch gel electrophoresis. Mosquito collections were sampled from four districts in Kanchanaburi Province where malaria is endemic. From eight enzyme systems, nine loci and seven polymorphisms were detected, indicating limited genetic differentiation among the seven collections (F(ST) = 0.061). The highest percent polymorphic loci were observed in Bong Ti Noi (BTN) Village (55.6%), whereas the least percent polymorphism was seen in Tha Kradan (TK) Village (22.2%). Comparing villages Pra Jedee (PJ) with Pu Teuy C (PTC) and Huai Khayeng (HK) with Pra Jedee (PJ), gene flow among collections varied from 3.72 to 62.25 reproductive migrants per generation. Among the seven collections, no correlation was seen between genetic and geographical distances (P > 0.05). Anopheles minimus (former species A) and Anopheles harrisoni (former species C) from Pu Teuy fit most closely in the same cluster, possibly indicating relatively recent divergence between taxa. The genetic and epidemiological ramifications of these findings are discussed.     

侯晨曦：附表1-附表2

本研究基于7个叶绿体DNA片段（cpDNA）和2个核DNA片段（ITS和PZ8）的测序数据,对龙血树柴胡（Bupleurum dracaenoides Huan C.Wang,Z.R.He&H.Sun）8个居群的153个样本进行了遗传多样性和分布式样研究。cpDNA片段分析结果显示：龙血树柴胡在物种水平具有较高的遗传多样性（H_d=0.862;P_i=0.00567）,但居群内遗传多样性低,遗传变异主要存在于居群间,遗传分化显著（F_st=0.959）;而核DNA片段ITS和PZ8的数据分析结果显示,其遗传多样性较低（H_d=0.532,P_i =0.00121和H_d=0.349,P_i=0.00060）,遗传变异主要存在于居群内,居群间仅存在一定程度的遗传分化。中性检验和失配分布分析结果发现龙血树柴胡没有经历过近期种群扩张事件,8个居群的153个样本从遗传成份上可被分为两组。研究结果将为龙血树柴胡的资源保护和发掘提供参考。     

Pretreatment of lignocellulosic material with fungi capable of higher lignin degradation and lower carbohydrate degradation improves substrate acid hydrolysis and the eventual conversion to ethanol

Phanerochaete chrysosporium, Pycnoporus cinnabarinus,and fungal isolates RCK-1 and RCK-3 were tested for their lignin degradation abilities when grown on wheat straw (WS) and Prosopis juliflora (PJ) under solid-state cultivation conditions. Fungal isolate RCK-1 degraded more lignin in WS (12.26% and 22.64%) and PJ (19.30% and 21.97%) and less holocellulose in WS (6.27% and 9.39%) and PJ (3.01% and 4.58%) after 10 and 20 days, respectively, than other fungi tested. Phanerochaete chrysosporium caused higher substrate mass loss and degraded more of holocellulosic content (WS: 55.67%; PJ: 48.89%) than lignin (WS: 18.89%; PJ: 20.20%) after 20 days. The fungal pretreatment of WS and PJ with a high-lignin-degrading and low-holocellulose-degrading fungus (fungal isolate RCK-1) for 10 days resulted in (i) reduction in acid load for hydrolysis of structural polysaccharides (from 3.5% to 2.5% in WS and from 4.5% to 2.5% in PJ), (ii) an increase in the release of fermentable sugars (from 30.27 to 40.82 g L(-1) in WS and from 18.18 to 26.00 g L(-1) in PJ), and (iii) a reduction in fermentation inhibitors (total phenolics) in acid hydrolysate of WS (from 1.31 to 0.63 g L(-1)) and PJ (from 2.05 to 0.80 g L(-1)). Ethanol yield and volumetric productivity from RCK-1-treated WS (0.48 g g(-1) and 0.54 g L(-1) h(-1), respectively) and PJ (0.46 g g(-1) and 0.33 g L(-1) h(-1), respectively) were higher than untreated WS (0.36 g g(-1) and 0.30 g L(-1) h(-1), respectively) and untreated PJ (0.42 g g(-1) and 0.21 g L(-1) h(-1), respectively).     

Schistosoma mansoni: Calcium efflux and effects of calcium-free media on responses of the adult male musculature to praziquantel and other agents inducing contraction

When male Schistosoma mansoni were incubated in a Ca²⁺-free medium their responsiveness to the contracture inducing agents, praziquantel (PZ), dinitrophenol (DNP), 60 mM K⁺ (high K⁺), ouabain, and low temperature, was rapidly attenuated. After 5 min in a zero Ca²⁺ medium the responsiveness to PZ was reduced by 60% but a residual response of 20% remained even after 40 min in a calcium-free medium. The contracture induced by ouabain or low temperature was totally lost within 1 min exposure to a zero Ca²⁺ medium. The efflux of ⁴⁵Ca²⁺ from parasites incubated in a medium containing no Ca²⁺ closely parallels the drop in responsiveness of their musculature to high K⁺, DNP, and PZ. The total amount of Ca²⁺ in the parasite was reduced by only 30% after 60 min in zero Ca²⁺ medium. A relatively rapid exponential decline in muscle tension was noted when parasites, previously treated with PZ, high K⁺, or DNP, were transferred to a medium containing these agents but with no Ca²⁺. Parasites that had been contracted with ouabain or low temperature showed no significant relaxation 16 min after transfer to a zero Ca²⁺ medium. The ⁴⁵Ca²⁺ efflux from worms bathed in zero Ca²⁺ medium was not significantly altered by the presence of ouabain. These results suggest the presence of active Ca²⁺ transport at the level of the parasites' muscle membranes.     

The projection domain of MAP4 suppresses the microtubule-bundling activity of the microtubule-binding domain

Microtubule-associated protein 4 (MAP4), a major MAP expressed in proliferating non-neuronal cells, consists of an N-terminal projection (PJ) domain and a C-terminal microtubule-binding (MTB) domain. The PJ domain of MAP4 is divided into three regions; the N-terminal acidic region (the Na-region), the multiple KDM-repeated sequence region (the KDM-region), and the b-region followed by the MTB domain. To investigate roles of the PJ domain, we prepared three truncated forms of human MAP4 with different PJ domain lengths; PJ1, PJ2 and MTB with deletion of about one-third, two-third and all of the PJ domain, respectively, and examined their effects on bundle formation of microtubules (MTs). MTs polymerized by full length MAP4 were singly distributed as observed by both negative staining electron microscopy and dark field microscopy. MTs with PJ1 were also separated in solution but became pairs when pelleted by centrifugation. PJ2 formed planar two-dimensional bundles consisting of several MTs (the 2D-bundle). MTB induced large bundles of many MTs, tightly packed without space in between (termed the 3D-bundle). To study how the PJ domain decreases the bundle-forming activity of the MTB domain of MAP4, we made three additional deletion-mutants of MAP4, called Na-MTB, KDM-MTB and Na-PJ2. Na-MTB and KDM-MTB, in which the KDM/b-region and both of Na- and b-regions were deleted respectively, were prepared by fusing the Na-region or KDM-region to MTB. Both of Na-MTB and KDM-MTB suppressed the 3D-bundle formation as effectively as PJ2. MTs polymerized with Na-PJ2, the KDM-deletion mutant made by adding the Na-region to PJ2, were singular and did not become bundles. These results indicated that the PJ domain kept individual MTs separated by suppressing the bundle-forming ability of the MTB domain. The suppressive activity of the PJ domain was correlated with the length, but not the amino acid sequence, of the PJ.     

Molecular cytogenetic analysis of the highly repetitive DNA in the genome of Apodemus argenteus, with comments on the phylogenetic relationships in the genus Apodemus.

The DNA of Apodemus argenteus was digested with DraI, and the resultant DraI fragment of highly repetitive DNA was isolated and analyzed by DNA filter hybridization, cloning, sequencing, and fluorescence in situ hybridization (FISH). Southern blot hybridization and nucleotide sequencing revealed that most of the DraI fragment consisted of a 230-bp repeating unit and contained no sex-chromosome-specific nucleotide sequences. The DraI fragment included the CENP-B box-like sequence, with a strong homology to the human CENP-B box sequence. FISH revealed that the DraI fragment was specific to all pericentromeric C-band-positive regions, as well as to the C-block of the X chromosome. No hybridization signals were obtained from A. speciosus, A. peninsulae peninsulae, A.p. giliacus, A. agrarius, A. sylvaticus, A. semotus, or Mus musculus when the DraI fragment was used as probe. Peptide nucleic acid (PNA)-FISH using the CENP-B box-like sequence in the DraI fragments as probe suggested that this nucleotide sequence was also specific to all pericentromeric C-heterochromatic regions of A. argenteus chromosomes. Zoo-blot hybridization using DraI-digested genomic DNA from three species of Apodemus (namely, A. argenteus, A. speciosus, and A. peninsulae) and from Mus musculus strongly suggested that the consensus DraI fragment contained nucleotide sequences that were species-specific for A. argenteus. These results also suggest that A. argenteus is phylogenetically distant from other Apodemus species examined, as well as the possibility that the DraI fragment might be related directly to the delayed quinacrine mustard fluorescence of many pericentromeric C-heterochromatic regions of the chromosomes in A. argenteus.