西门塔尔牛胰腺间充质干细胞原代培养及其多向分化潜能研究

旨在对西门塔尔牛胰腺间充质干细胞（pancreatic mesenchymal stem cells,PMSCs）进行原代培养并研究其体外分化潜能,为细胞疗法和组织工程学方面提供新的种子细胞。本研究从3月龄的西门塔尔牛胚胎中无菌分离胰腺组织,分别采用胶原酶消化法和组织块贴壁法分离PMSCs,进行原代培养;绘制第3代、第9代、第15代细胞生长曲线并测定群体倍增时间及克隆形成能力,采用免疫荧光检测干细胞表面标志物（CD29、CD44、CD73、CD90、CD34和CD45）,RT-PCR检测干细胞细胞表面标志物（CD29、CD44、CD73、CD90、CD106、CD166、CD34和CD45）;染色体核型分析检测其基因稳定性,通过向成脂、成骨、成软骨和成肝样细胞诱导分化,检测其多向分化潜能。结果表明,两种方法都可成功分离出PMSCs,细胞贴壁后形态均为长梭形,漩涡状生长,生长趋势呈典型的S形;第9代细胞群体倍增时间显著低于第15代而高于第3代（P<0.01）;第9代PMSCs克隆形成率显著低于第3代而显著高于第15代（P<0.05）;免疫荧光结果表明,PMSCs特异性表达CD29、CD44、CD73和CD90,RT-PCR结果显示PMSCs特异性表达CD29、CD44、CD73、CD90、CD106和CD166,未表达造血细胞表面标志物CD34和CD45,与国际细胞治疗学会组织干细胞委员会指定的MSCs表面标记物相对应;核型分析表明,PMSCs为正常二倍体（2n=60,XY）,染色体基因组未发生变异;特异性染色和RT-PCR结果表明,从西门塔尔牛体内获得的PMSCs可分化为脂肪细胞、骨细胞、软骨细胞和肝样细胞。本试验证实两种方法均可成功建立西门塔尔牛PMSCs体外分离培养体系,PMSCs具有活性好、增殖速度快的特点,与MSCs有相似的生物学特性和多项分化的潜能。可为组织工程学提供新的种子细胞。     

奶牛乳腺上皮细胞的原代培养及其生物学特性分析

旨在从奶牛乳腺组织中分离原代乳腺上皮细胞（bovine mammary epithelial cells,BMECs）并传代培养后探究其生物学特性。本研究从屠宰场采集健康泌乳奶牛乳腺并采用改进的酶消化法从乳腺中分离得到原代奶牛乳腺上皮细胞,通过形态学观察、免疫荧光以及染色体核型分析的方法对其进行鉴定。同时,研究第3、第6和第9代乳腺上皮细胞的生长曲线、群体倍增时间和冻存复苏活力,检测不同代次细胞分泌乳蛋白、乳脂、乳糖的功能及泌乳相关基因的表达。结果表明,所分离的奶牛乳腺上皮细胞纯度较好,细胞生长呈现S型,3个代次细胞的群体倍增时间依次为34.87、41.45和65.04 h,冻存复苏活力为88%~93%;在细胞分泌功能方面,诱导培养2 d后均能检测到酪蛋白、甘油三酯和乳糖,且各代次间无显著差异;此外,3个代次的细胞诱导后均能表达乳成分合成相关基因。本研究成功培养了原代奶牛乳腺上皮细胞,并证明直到第9代细胞仍然具有正常的生物学功能,为体外探究乳腺细胞增殖与分化机制提供了良好的试验材料和技术支撑。     

曹州木瓜果实香气物质的研究

利用顶空固相微萃取法提取芳香物质,气相色谱-质谱联机定性定量分析,测定曹州木瓜狮子头、剩花、豆青和玉兰的挥发性物质,并对木瓜不同品种的香气组分进行分析探讨.共测定出145种香气组分,曹州木瓜狮子头、剩花、豆青和玉兰分别为70、70、69和70种,各自占总峰面积的99.88%、99.7%、99.97%、99.37%,以醇类、醛类、烯烷类、酮类、酯类、杂环类等为主,其中又以C6醇(如1-己醇、2,4-己二烯-1-醇、反式-2-甲基-环戊醇等)、C6醛[(E)-2-己烯醛、2-己烯醛、E,E-2,4-己二烯醛等]居多.结果表明:狮子头、剩花、豆青和玉兰不同品种香气组分存在一定的差异,但大部分主要组分相同;主要组分含量差异是曹州木瓜不同品种间香气不同的主要原因.     

Nutrient dynamics in a mangrove creek (North Brazil) during the dry season

During the dry season, dissolved inorganic nutrients and organic carbon (DOC) in a mangrove tidal creek (Bragança, North Brazil) presented a clear tidal signature: silicate, phosphate, ammonium and DOC covaried with salinity, with minima at high tide and maxima at low tide. Hydrodynamical calculations explained most diel variability as dilution of nutrientrich groundwater input by estuarine water. Creek nutrients tended to lower concentrations towards the end of the dry season, probably due to changes in groundwater dynamics. Ammonium was about 44% higher in the night than during the day, while silicate, phosphate nitrate + nitrite showed differences < 5%, indicating preferential autotrophic uptake of ammonium as nitrogen source. Nitrification and/or nitrogen fixation are probably sources of nitrate + nitrite, which contributed only 12% to the dissolved inorganic nitrogen pool. Dissolved oxygen (7%) and DOC (11%) were lower during the night, suggesting the existence of a labile, algalderived DOC pool. There is a loose coupling between aquatic primary production, groundwater dynamics and tidal regime.     

尾叶桉幼林地上部分生物量及养分循环的研究*

论述了２－３年生尾叶桉幼林地上部分生长、生物量积累和生物量在树木各器官及各径阶中的分配，林分净生产量，树木各器官及凋落物的养分含量和林分的养分循环。２年生时林分的生物量为２２．９ｔ／ｈｍ＾２，其中干材占６０．２％，皮占８．９％，枝占１４．７％，叶占１６．２％。３年生时林分生物量为４０ｔｈｍ＾２，其中干材占６３．６％，皮占７．７％，枝占１４．１％，叶占１４．６％。年净生产量为２０．５ｔ／ｈｍ＾２，约     

Storage of biomass and net primary productivity in desert shrubland of Artemisia ordosica on Ordos Plateau of Inner Mongolia, China

Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.     

Dry matter production and nutrient cycling in agroforestry systems of mandarin grown in association with Albizia and mixed tree species

A study on dry matter production and nutrient cycling in agroforestry systems of mandarin grown in association with N₂-fixing Albizia and mixed tree species (non-N₂-fixing) was carried out in the Sikkim Himalaya. A site with Albizia was referred asAlbizia-mandarin stand and the other site with mixed tree species as mandarin stand. The stand total biomass, net primary productivity and mandarin fruit production was higher under the influence of Albizia. Agronomic yield of crops remained nearly the same in both the stands. Nitrogen and phosphorus concentrations of different components of Albizia were higher than those of mixed tree species, whereas their back translocation from leaf to branch before abscission was lower inAlbizia. The mandarin-based agroforestry is a highly nutrient-exhaustive system evaluated in terms of nutrient exit through the removal of agronomic yield. This system, under the influence of Albizia, was more productive with faster rates of nutrient cycling. Nutrient use efficiency increased under the influence of Albizia, in contrary to the hypothesis that efficiency should decrease with increasing rate of uptake. The poor nutrient conservation of Albizia, and malleability of nutrient cycling under its influence make it an excellent association which promotes higher availability and faster cycling of nutrients.Albizia should be utilised more extensively in the management of mandarin-based agroforestry systems.     

Leaf conductance of primary and mature leaves ofPinus roxburghii: A comparison

We used a null-balance porometer to measure leaf conductance of mature and primary leaves of natural seedlings, saplings, and trees ofPinus roxburghii (chir) during autumn at four sites at 1,320–1,930 m elevation in the central Himalaya of India. Our hypothesis that primary leaves had higher leaf conductance than mature leaves (needles in fascicles), based on measurements in other pines, was rejected. Comparisons on the same saplings and seedlings showed lower leaf conductance for primary leaves than for mature leaves. Primary leaves on seedlings and saplings also did not consistently have higher leaf conductance than mature leaves on near-by trees. Mature leaves on seedlings, however, did often have higher conductance than mature leaves on nearby trees. Mean values for leaf conductance (mmol m⁻² s⁻¹, based on total leaf surface area) ranged from 42–82 for mature leaves on trees, 60–121 for mature leaves on seedlings, and 28–67 for primary leaves on seedlings. Compared to published values for other pine species, conductance of mature leaves ofP. roxburghii is relatively low. Funding for this study was provided by grants from the United States National Science Foundation, INT-9312052 and INT-9404043. We appreciate the review of an early draft by Barbara Bond.     

Protective effect of butylated hydroxylanisole against hydrogen peroxide-induced apoptosis in primary cultured mouse hepatocytes

Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H₂O₂)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H₂O₂ in a dose-dependent manner. Additionally, H₂O₂ treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H₂O₂ significantly attenuated the H₂O₂-induced decrease of cell viability. H₂O₂ exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H₂O₂-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H₂O₂-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H₂O₂-induced apoptosis by inhibiting ROS generation.     

Evaluation of embryonic age and the effects of different proteases on the isolation and primary culture of chicken intestinal epithelial cells in vitro

The present study evaluates the effects of embryonic age and proteolytic enzymes on the isolation and primary culture of chicken enterocyte and to establish an effective technique for chicken intestinal epithelial cell (IEC) cultivation. Fourteen‐day‐old, 16‐day‐old and 18‐day‐old embryos (average weight: 52.23 ± 0.76 g, 50.86 ± 0.99 g, 48.98 ± 1.03 g) were the source for preparation of enterocyte culture, and trypsin‐ethylene diamine tetraacetic acid, collagenase, thermolysin and combination of collagenase and thermolysin were used for digestion medium. Optimal culture protocols were determined by qualitative assays of proliferation. Cells isolated by using 14‐day‐old embryo and collagenase obtain the best attachment and growth in culture, and the production of continuously growing IEC cultures. Thus, we conclude that the use of collagenase as a dissociating enzyme and 14‐day‐old embryo as a source can be advantageously applied to the isolation of chicken IEC and this method may be useful for various applications and basic studies of the intestinal tract concerning such objects as physiology, immunology and toxicology.