根癌农杆菌介导的巴西橡胶树胚性悬浮细胞的遗传转化

为了建立橡胶树胚性悬浮细胞遗传转化体系,用根癌农杆菌EHA105（携带pCAMBIA1301,含有gusA和hpt Ⅱ）侵染胚性悬浮细胞团,用GUS检测的方法分析了共培养时间和菌液浓度对转化效率的影响;同时,测定了胚性细胞团对潮霉素敏感性。结果表明适宜的共培养时间为3天,适宜的菌液浓度为OD600=0.4~0.6。潮霉素的致死剂量为15 mg/L。使用大约1 g鲜重的胚性细胞团,经过转化和选择培养,获得53块抗性愈伤组织,经诱导获得7个体细胞胚。GUS检测和PCR鉴定证实了gusA基因已经整合到橡胶树基因组中。本研究为根癌农杆菌介导的橡胶树胚性悬浮细胞遗传转化体系建立奠定了基础。     

Effect of supplementation of calf starter with fennel powder on performance,weaning age and fermentation characteristics in Holstein dairy calves

The objective of this experiment was to investigate the effects on performance, weaning age and rumen fermentation characteristics in Holstein calves when fennel powder was added to their starter diets. Thirty Holstein calves with a mean birth weight 40 kg (SD = 0.5) were allocated randomly to one of the following experimental diets: (i) control (starter diet without fennel powder), (ii) starter diet containing 0.4% of fennel powder and (iii) starter diet containing 0.8% of fennel powder (DM basis). The effect of treatments on mean dry matter intake was significant (p < 0.05) in the post‐weaning and total experimental periods. Average daily weight gain before (0.38, 0.49 and 0.47 kg/day) and after (0.6, 1.01 and 0.83 kg/day) weaning and during the entire study (0.45, 0.7 and 0.58 kg/day) was influenced by diets of 1, 2 and 3, respectively (p < 0.05). Maximum daily weight gain and the best feed conversion ratio were achieved with 0.4% fennel powder. Mean weaning age of the calves supplemented with fennel powder was lower (p < 0.05) than that of the control group. Ruminal fluid pH in calves offered starter containing 0.8% fennel powder was lower (p < 0.05) compared to calves fed the other diets. Ammonia nitrogen content increased (p < 0.05) in the third week of feeding fennel powder. The mean concentration of total short‐chain fatty acids (SCFA) and propionate molar percentage in the ruminal fluid of the calves fed with the fennel powder were higher (p < 0.05) at 6 weeks and 2 weeks after weaning than control group; however, acetate‐to‐propionate molar ratio was lower (p < 0.05). The results showed that adding 0.4% fennel powder to the starter increased the propionate molar percentage in the rumen and improved the calf performance, allowing the calves to be weaned at an earlier age.     

真菌诱导子对南方红豆杉细胞生长及紫杉醇合成的影响

用真菌诱导子处理南方红豆杉(Taxus chinensis var.mairer)悬浮细胞,测定细胞生长指数、紫杉醇含量及其细胞酶活的变化,初步探讨真菌诱导子对南方红豆杉悬浮细胞生长的影响。结果表明,在细胞悬浮培养第8天加入100μg/m L真菌诱导子,可明显增加悬浮细胞的生物量,紫杉醇的含量也有提高;添加真菌诱导子能抑制细胞多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性,有利于细胞生长。     

籼型水稻不育系Ⅱ－32A和优ⅠA花培提纯研究

籼型水稻不育系Ⅱ－３２Ａ和优ⅠＡ同为印尼水田谷６号胞质。利用花培纯合效应，于１９８９年对这２个不育系及其相应保持系同步进行了花药培养，诱导出了一批正常二倍体花粉植株，并通过逐代测配筛选、行性鉴定和配组，杂交优势比较，获得了基因纯合、遗传稳定的Ⅱ－３２Ａ和优ⅠＡ的优良花培提纯株系。     

酸奶发酵剂生产技术及其质量控制

本文着重从酸奶发酵剂培养基的加热强度、菌种选择及接种周期等方面进行质量控制.结果表明,高质量的菌种培养基热处理强度以1kg/cm~2保持15min为宜,接种周期不得超过7-10天.     

Quantitative bacterial cultures and cytological examination of bronchoalveolar lavage specimens in dogs

Cytology and quantitative bacterial cultures of lower respiratory tract secretions are widely used in human medicine to differentiate airway infection from simple bacterial colonization. A retrospective study was conducted to determine the usefulness of quantitative aerobic cultures and Gram stain intracellular bacteria counts from bronchoalveolar lavage (BAL) specimens in dogs in diagnosing lower respiratory tract infection (LRTI) and to determine whether chronic bronchitis is associated with marked bacterial growth in dogs. The threshold determined to define clinically relevant bacterial growth was 1.7 x 10(3) colony-forming units per milliliter of BAL fluid. We used this threshold and found that diagnostic sensitivity and specificity were 86% and 100%, respectively. With a threshold for infection of >2 intracellular bacteria observed in any of 50 fields, microscopic examination of Gram stain BAL preparations had a sensitivity of 71% and a specificity of 97% in establishing LRTI. There was a high correlation between bacterial morphology on BAL Gram stain and bacterial cultures. Combining the results of intracellular bacteria counts from the BAL Gram stain with those from the quantitative cultures, the sensitivity in diagnosing LRTI was 87% and the specificity was 97%. BAL quantitative cultures as well as quantitating intracellular bacteria on Gram stain BAL cytology were revealed to be useful in identifying LRTI in dogs. Chronic bronchitis does not appear to be associated with marked bacterial growth in dogs.     

Inhibition of in vitro lymphocyte blastogenesis by chicken alpha-fetoprotein

Chicken alpha-fetoprotein (ch-AFP), purified from fetal chicken serum and embryo extracts, respectively, was examined for its immunomodulatory effect in vitro. Significant (P less than 0.05) suppression of the allogeneic mixed lymphocyte reaction (MLR) was observed, when these preparations were added to one-way mixed lymphocyte cultures (MLC) in quantities of 62.5-1000 micrograms/ml. Suppression of the MLR was depending on the presence of ch-AFP for at least 16 h after initiation of the MLC, suggesting that this fetal protein was acting mainly in the early phase of lymphoblastogenesis. Serum of chicken embryos (12th and 15th day of incubation), day-old chickens, and of 10-week-old chickens of four different inbred lines were also found to exert suppression of the MLR. From these data, it is hypothesized that ch-AFP plays an immunoregulatory role by maintaining a certain stage of self tolerance during differentiation of the avian immune system.     

大花君子兰幼胚培养研究

用授粉后１０８天的大花君子兰幼胚离休培养表明，幼胚发芽力与胚大小有关。ＭＳ＋ＫＴ１．０ｍｇ／ｌ＋ＮＡＡ０．５ｍｇ／ｌ的培养基有利幼胚发芽。１／２ＭＳ培养基中添加ＩＢＡ０．１ｍｇ／ｌ、ＩＢＡ０．５ｍｇ／ｌ＋活性炭３ｇ／ｌ或ＩＢＡ１．０ｍｇ／ｌ＋活性炭３ｇ／ｌ都能使幼苗生根。试管培养具有促进幼胚发芽、缩短育苗时间的显著效果。     

开食料对犊牛生长发育的影响

利用20头8日龄黑白花公犊研究开食料中添加乙酸钠和瘤胃酶制剂对其生长发育的影响,持续60天。结果表明:开食料及添加剂对公犊生长有明显的促进作用。试验组总增重、胴体、腓肠肌重以及瘤网胃重量均显著高于对照组,分别为:31.3±1.33kg,37.2±1.16kg,0.624±0.02kg,1.30±0.07kg。而对照组相应为:26.70±0.95kg,33.3±1.16kg,0.555±0.01kg,1.06±0.04kg。肌肉组织代谢分析表明:开食料及添加剂具有加强组织代谢,促进肌肉蛋白合成之功效。试验组腓肠肌总RNA 和 RNA/干重比对照组分别提高20.89%(P<0.01)和10.83%(P<0.01),GPT/DNA 增加46.32%(P<0.05)。血清三碘甲腺原氨酸(T_3)浓度提高14.28%(P<0.05)。提示:开食料中添加乙酸钠和瘤胃酶制剂能促进瘤胃发育,改善代谢过程,提高生长速度。     

Long-term callus cultures of diploid Barley (Hordeum vulgare). I. Auxin effects on culture initiation and maintenance

Summary Use of 2,4-D was superior to NAA or IAA for embryogenic callus initiation or maintenance in barley cultivar Bruce. A concentration of at least 2.0 mg/l 2,4-D was desirable for culture initiation. The developmental size of the embryo was more important than embryo age for obtaining embryogenic calli. Even brief exposures (20–40 days) of calli to concentrations of higher than 5.0 mg/l 2,4-D or 10.0 mg/l NAA resulted in inhibition of subsequent plant regeneration and therefore, concentrations above these could not be used for maintenance cultures. In the long-term maintenance cultures, the best production of embryogenic calli was with 0.1 mg/l and 1.0 mg/l 2,4-D.