Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from alpha 1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GaIT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GaIT-KO pigs to humans.

Immunolocalization and expression of vascular endothelial growth factor receptors (VEGFRs) and neuropilins (NRPs) on Keratinocytes in human epidermis

Vascular endothelial growth factor (VEGF) plays an important role in normal and pathological angiogenesis. VEGF receptors (VEGFRs, including VEGFR-1, VEGFR-2, and VEGFR-3) and neuropilins (NRPs, including NRP-1 and NRF-2) are high-affinity receptors for V

鼠尾藻的生理生态和繁殖生物学研究

鼠尾藻 [Sargassum thunbergii (Mert.) O’Kunte] 是北太平洋西部特有的一种暖温性大型经济褐藻，在我国沿海地区北起辽东半岛南至雷州半岛的硇州岛，都有广泛分布。鼠尾藻在食品和医药领域的应用开发在我国有悠久历史。近年来，随着水产动物养殖业迅速发展，其应用领域得到了进一步拓展，发现鼠尾藻是海参、鲍鱼等水产动物的优质天然饵料。 受海参和鲍鱼产业发展影响，鼠尾藻的市场需求量成倍增加。目前鼠尾藻的供应全部依赖自然资源。掠夺式的采收方式导致鼠尾藻的野生资源遭到了很大破坏，种群规模和数量不断减小，生态环境也发生了变化。近年来鼠尾藻供需矛盾已经非常突出，如何保护和有效利用该海藻资源已经成为海藻科研和产业界的一个重要话题。 以往对鼠尾藻的生态学和人工育苗技术方面的比较深入的研究工作很少，许多基础科学问题研究不够，人工繁殖技术没有很好地掌握，已经不能满足产业发展需求并限制了鼠尾藻应用价值的发挥。为此，有必要系统性研究鼠尾藻原生态环境、野生状态下生长发育的年际交替规律、鼠尾藻有性生殖过程、人工育苗方法途径、鼠尾藻吸收无机营养能力、以及在调控藻际菌群能力等基础科学技术问题，带动鼠尾藻饵料规模的良性健康扩大，并进一步推动海参和鲍鱼等水产业的发展。 本文以青岛汇泉角的鼠尾藻为基本实验材料，通过野外实地周年观察并结合实验室工作，对上述问题初步进行了初步探索，主要获得如下结果： （1）在青岛地区海滨岩石地带，全年都可观察到鼠尾藻藻体，藻体的形态大小和生理发育状况随季节变化表现出很大的差别性。夏季藻体黄褐色，初生分枝伸展，有次生分枝、生殖枝和气囊的发育，而冬季的藻体黑褐色，初生分枝粗短，没有次生分枝、生殖枝和气囊的发育。6月鼠尾藻出现有性生殖器官生殖托，到7月生殖托发育成熟，7月藻体最长，平均在50厘米左右，11月可观察到有性生殖和假根产生的幼苗。假根营养繁殖再生苗是鼠尾藻种群新苗源的主体，在维持种群自然繁衍和发展中起主导作用。 （2）有性生殖过程是鼠尾藻个体发育的大事件，精卵结合产生幼苗的潜力巨大，是开展未来规模化人工育苗的希望依托。鼠尾藻初生分枝长度和外形株间差异较大，每株鼠尾藻平均大约有20个初生分枝，约一半初生分枝可发育成熟，充分发育的初生分枝可产生30－50个次生分枝，每个次生分枝上又有大约20－30个生殖枝，每个生殖枝上生殖托数量一般为1－3个，雌托长度大多在3－5mm，雄托长度在10－15mm。生殖托的成熟度由基部向顶端递减。一个雌托排卵量平均为400多粒。以此计算，每株雌性鼠尾藻在生殖季节可产生200多万个卵。 卵从生殖窝孔排出后粘附于雌托表面，雄托排精时间稍晚于雌托挂卵时间，精子游动到卵周围与之结合完成受精过程。受精卵大约在受精后1小时分裂为两个大小相近的细胞，2小时后再进行第二次分裂，其中一个细胞横裂为两个细胞：一个细胞较大，另一个细胞较小，另一个细胞的分裂面与第一次分裂垂直，等分为两个细胞，随后细胞不断分裂。在受精后48小时左右，胚苗一端产生出假根。胚苗从雌托脱落的第一周内，尽管细胞数量增加较快，但新细胞体积减小，使得胚苗的体积增加不多。从第二周开始幼苗的体积出现明显的增加。此时，无机营养盐的有效补充对鼠尾藻幼苗培养长大是十分必要的。下海后的管理是保障幼苗成活的关键，此时常常发生脱苗现象。 （3）鼠尾藻对无机氮、磷都有较强的吸收能力，鼠尾藻从海水中吸收无机氮和无机磷的能力分别为75.1mg/kg/day和36.2mg/kg/day，鼠尾藻对氮、磷吸收的质量浓度比例接近5：1。 （4）鼠尾藻具有调节藻际微生物种群的能力，鼠尾藻对弧菌和总异养菌菌群都有一定程度的抑制作用，研究发现鼠尾藻抑制弧菌的能力存在种的差异，其中对鳗弧菌65#显示的抑制作用最强，鼠尾藻的抑菌能力的强弱还与其生理状态的好坏有显著关系。 通过上述研究结果，我们认为：鼠尾藻通过有性生殖过程培育种苗在理论上具有可行性，发展潜力很大。而解决幼苗后期培养中的脱苗问题、提高苗的成活率是下一步需要研究攻克的关键技术；假根营养繁殖再生苗源是维持该藻自然种群的主要方式，也是目前开展人工养殖获得健壮苗种的重要途径，连根采收方式对鼠尾藻野生资源破坏严重；建议野生鼠尾藻在7月底到8月初（水温27℃左右）采收（此时藻体生物量接近最大、并完成生殖过程），采用剪切方式保留假根和幼小的初生枝收获，该方式还可以应用到收获人工筏式养殖的鼠尾藻中，这对保证假根的完整性，大量获得下一个栽培季节的健壮新苗有实际意义；建议进一步开发鼠尾藻吸收富营养化物质、净化养殖环境水质的能力，以及对弧菌和总异养菌的抑制能力，建立海参、鲍鱼和鼠尾藻生态互补、环境友好的养殖模式，控制病害发生，提高水产品产量和质量。

Experimental and field studies of Mesocyclops notius (Copepoda : Cyclopoida) from a subtropical Chinese lake, Lake Donghu

This paper reports experimental and field studies on the cyclopoid Mesocyclops notius from subtropical Lake Donghu close to the Yangtze river. Mesocyclops notius, a dominant crustacean Zooplankter throughout tropical Australia, was previously considered to be endemic to Australia, but recently, Mesocyclops leuckarti in Lake Donghu was re-identified as M. notius. Laboratory culture experiments were conducted to reveal the effect of temperature (15, 20, 25 and 30 degreesC) on the development, growth and reproduction of M. notius. Temperature was inversely related to development times of eggs, nauplii and copepodites, body length and physiological longevity of adults, and brood size. Body length and physiological longevity of females were greater than those of males at the same temperature. No reproduction took place at 15 degreesC. Production and seasonal cycles of M. notius during 1980-1982 were studied at two sampling stations of Lake Donghu. At the mid-lake station, the annual production and production/biomass (P/B) ratio of M. notius varied between 6.0 and 18.0 g dry wt m(-2) year(-1) and 74.6 and 95.5, respectively. Mesocyclops notius reached their highest density peaks in the warm months (July-October), with a maximum density of 1256 individuals l(-1) at a littoral site. No reproduction and recruitment by AL notius took place during the cold months (December March) when the temperature of the lake water was < 15 degreesC. Mesocyclops notius were more abundant at a littoral station than at a pelagic station, possibly due to different food availability. The higher male:female sex ratio of M. notius at the littoral station was most likely caused by size-selective fish predation on larger females.