Comparison of harvested rate and nacre deposition parameters between cultured pearls issued from initial graft and second nucleus insertion in P. margaritifera

Cultured pearls produced with Pinctada margaritifera, using the surgreffe method (implantation of a second nucleus following pearl harvest) were studied for the first time to: (1) examine family effect on nacre thickness, nacre weight and nacre deposition speed and (2) compare variation in these three traits with that obtained from the cultured pearls previously harvested after the corresponding initial grafts. A surgreffe experiment using 783 recipient oysters was realized in Rangiroa atoll (French Polynesia). After 24 months of culture, 389 cultured pearls were harvested. Significant donor family effect was found for the harvested pearl rate from surgreffe (P = 0.046). Highly significant donor family effect was recorded for nacre thickness (P = 0.004). Very highly significant donor family effects were recorded for nacre weight and nacre deposition speed (P < 0.0001). Comparison between surgreffe and initial graft showed: (1) no significant effect for the average cultured pearl rate harvested (P = 0.052) and average cultured pearl nacre deposition speed (P = 0.622) and (2) very highly significant differences (P < 0.0001) for the average cultured pearl nacre thickness and nacre weight. This study highlighted three major implications for pearl industry management: (1) donor family effect was maintained from initial graft to surgreffe, for nacre thickness, weight and deposition speed, (2) the persistence of the pearl sac metabolic activity over three years of culture and (3) the relation between harvested pearl rate and the size of the nucleus inserted in the pearl sac.     

Cultured meat from muscle stem cells:A review of challenges and prospects

Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called "cultured" or "synthetic" or "in vitro" meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.     

水培茶苗对氟的吸收累积特性

为了探讨茶树对氟的吸收累积特性,以无性系茶苗为材料,研究水培条件下培养时间和培养液氟浓度对茶苗吸收累积氟的影响以及无氟条件下茶苗体内氟的转移。结果表明,茶苗具有对氟的高富集性和强耐受性。茶苗体内的氟具有可转移特性。茶苗各器官氟含量随处理的时间呈线性增长,老叶氟含量高达6809·39mg/kg。不同氟浓度下对氟的吸收累积符合Michaelis-Menten模型。无氟处理下,茶苗根系和新梢的氟累积倍数随时间呈线性增加。     

环境因子对春季大棚早熟苋菜部分品质性状的影响

研究了塑料大棚内的光照强度、气温、地温、CO2浓度及氮肥施量5个环境因子5水平的处理组合对春季早熟苋菜栽培营养品质与外观品质的影响。结果表明,苋菜体内硝酸盐含量由低到高的次序为AB>C>D>E,其中VC含量后4者比处理A分别减少了11.7%,18.4%,31.3%和32.4%,在处理A、B内,随氮肥水平提高VC含量增加,其余处理氮水平间变化不大。花青素含量分别减少了18.6%,23.5%,39.2%和52.9%,在各处理内随氮水平提高而增加,变化幅度较大。不同处理粗纤维和还原糖含量变化呈现相同趋势:B>A>C>D>E,但不同氮水平间变化趋势两者相反。光照强度显著或极显著地影响各品质指标的变化,是春季大棚早熟苋菜栽培能否获得优质的首要因子。综合评判各环境因子组合,B组(0网1膜,平均光强17 800 lx,地温21.2℃,气温23.5℃和CO2浓度1 500μmol/mol)在施氮水平为N5(300 kg/hm2)时,可以实现苋菜的优质栽培。     

野生与养殖银鲳幼鱼氨基酸含量的比较

比较了野生与养殖银鲳幼鱼氨基酸的含量。结果显示,野生与养殖银鲳鱼体中均以谷氨酸含量最高,组氨酸含量最低,必需氨基酸中均以赖氨酸含量最高,并且四种呈味氨基酸的含量由高到低的顺序均为谷氨酸>天冬氨酸>甘氨酸>丙氨酸。养殖银鲳鱼体中脯氨酸含量较野生银鲳明显升高(变异系数为11.16%),但丝氨酸、酪氨酸及八种必需氨基酸(缬氨酸、蛋氨酸、亮氨酸、异亮氨酸、苏氨酸、苯丙氨酸、赖氨酸及精氨酸)的含量均较野生银鲳低。养殖银鲳氨基酸总量(54.17 g/100 g干物质)与必需氨基酸总量(27.16 g/100 g干物质)均分别低于野生银鲳鱼体中的氨基酸总量(57.92 g/100 g干物质)与必需氨基酸的总量(30.04 g/100 g干物质),变异系数分别为4.74%与7.13%;而呈味氨基酸总量与野生银鲳相比差异较小,变异系数仅为2.66%。养殖银鲳与野生银鲳鱼体中必需氨基酸总量与总氨基酸的比值(EAA/TAA)均较高,分别为50.14%与51.87%。此外,养殖与野生银鲳鱼体中的呈味氨基酸与总氨基酸(DAA/TAA)的比值同样较高,分别为37.92%与36.82%。     

人工培植羊黄的研究 Ⅰ.湖南山羊植黄手术探讨

选自浏阳、湘潭农户放牧的健康山羊93只(其中黑山羊53只、麻山羊40只),根据羊只毛色不同.比较了植黄手术中羊只品种、体重、胆囊三者的关系,和手术部位前后的情况。结果表明:①麻羊胆囊比黑山羊胆囊极明显小些(P<0.01);②胆囊大小与体重成正比;③手术部位以倒数2～3肋间较适宜;④黄床应根据胆囊大小而定.     

体外培养牛腔前卵泡颗粒细胞的超微结构研究

透射电镜下，简易机械法分离得到的腔前卵泡有1～3层颗粒细胞，相邻颗粒细胞间存在明显而广泛的间隙连接，卵泡基膜完整，外无卵泡膜。培养过程中超微结构的变化与体内发育腔前卵泡类似。培养6d时观察到颗粒细胞增殖现象，培养15d时，个别卵泡的内膜细胞开始形成。超微结构研究结果表明，本培养体系适于小腔前卵泡的体外培养。     

Lipid composition and deposition of cultured yellowtail Seriola quinqueradiata muscle at different anatomical locations in relation to meat texture

ABSTRACT:   The present study was undertaken to assess the lipid composition and deposition in muscle at three anatomical locations in cultured yellowtail and to investigate the effect of lipid composition and deposition on meat texture. Lipid deposition in muscle was studied by histochemical staining of lipid with Sudan dye. Lipid class composition analysis showed that neutral lipids were the main constituents of lipid in cultured yellowtail and accounted primarily for the variation in muscle lipid content with the anatomical location of meat, as well as with season, whereas the polar lipid content remained almost constant. Furthermore, muscle neutral lipid content was correlated negatively with meat breaking strength; however, no correlation was observed between muscle polar lipid content and meat breaking strength. The histochemical study revealed that, in yellowtail muscle, lipid is preferentially deposited in the myosepta and, with increases in muscle lipid content, additional fat is deposited along sparsely distributed thin connective tissue. It was also observed that the greater the lipid deposition in collageneous connective tissue, the lower the meat breaking strength; presumably, higher lipid deposition in the connective tissue resulted in weakening of the muscle structure.     

幼穗无性系变异在小麦育种上的应用

冬小麦(综抗矮6号×泰山1号)F_1代花培H_1代纯系经幼穗离体培养建立的13—7管无性系获得一株R_0代种子,后代变异类型多、频率高,其R_2、R_3代株高、抽穗期都呈一个正态分布、连续性变异,调查的几个性状在R_3代稳定率已达84.85—100％。已从稳定品系中选择出一批不同株高和高蛋白材料,其中4个品系比对照冀麦6号增产17.2—35.8     

观赏百合组培苗移植试验

研究了不同介质、不同大小百合种球、不同移植季节及不同晾干时间对百合移植成活率、根系生长及叶、芽生长的影响，结果表明：10种试验介质中百合移植的最佳介质是100％珍珠岩或50％珍珠岩＋50％泥炭土，百合种球适宜直径为≥0．5cm，合适季节为春、秋季，晾干2．3d的百合种球的成活率仍可达80％以上，如果介质、种球大小、移植季节合适，百合组培苗不经过炼苗也可达到90％以上的成活率。