甜菜干种球与萌芽种球诱变四倍体效果比较

为了探索甜菜四倍体诱变方法,分别用0.3%和0.4%秋水仙碱溶液诱变处理甜菜干种球和萌芽种球.结果表明,干种球处理的种子诱变率在1%～6% ,萌芽处理的种子诱变率在8%～16% ,萌芽种球的诱变率显著高于干种球.秋水仙碱液浓度对诱变率也产生较大影响,干种球与萌芽种球均以0.4%秋水仙碱溶液处理的诱变效果最好.     

耐酸耐胆盐嗜酸乳杆菌的紫外诱变选育

通过紫外诱变提高嗜酸乳杆菌的耐酸耐胆盐能力。通过正交试验确定了诱变参数：20 W紫外灯,菌液稀释至OD6000.65左右,照射60 s,照射距离为30.5 cm,此条件的致死率为90.5%。诱变处理后的菌体在模拟人肠道胆汁盐浓度（0.3%）以及pH=2的选择性培养基中处理不同时间后,活菌计数,最终筛选出具有耐胆盐能力显著增强的突变体L.a.abr。在含0.3%胆盐和pH为2的选择性培养基中培养1.5、2.0、2.5 h时的存活率分别为19.57%、10.87%和4.78%,而出发菌株的相应存活率分别为3.68%、1%、0.23%。     

EMS诱变甘蔗愈伤组织的初步研究

为了探索EMS对甘蔗愈伤组织进行化学诱变的合适浓度和时间组合,以ROC22和粤糖93-159甘蔗愈伤组织为材料,研究了不同浓度(8、24、40μmol/L)、不同时间(2、4、6 h)诱变处理对愈伤组织的每克鲜重相对增重量和相对分化率的影响。并通过分化试验选择适合诱变后愈伤组织分化的培养基。结果表明,适合诱变处理后愈伤组织分化的培养基为:MS基本培养基+2 mg/L KT+2 mg/L NAA+3.0%蔗糖(W/V)+0.8%琼脂(W/V)。适合EMS诱变甘蔗的处理为:24μmol/L诱变处理2 h或8μmol/L诱变处理6 h。     

秋水仙素诱导维多利亚葡萄试管苗多倍体研究

本实验采用0.05％、0.1％的秋水仙素溶液对维多利亚葡萄试管苗单芽茎段进行24 h、48 h浸泡处理来诱导发生多倍体.对诱变四倍体和二倍体进行染色体、保卫细胞叶绿体等进行比较.结果表明:0.1％的秋水仙素处理24 h对诱导葡萄发生多倍体效果最好.加倍率从M1代的40.9％提高到M9代的75.8％.根尖染色体压片检查表明,四倍体染色体数为2n=4x=76,二倍体对照为2n=2x=38.四倍体植株叶片表现气孔密度减小,气孔保卫细胞增大,保卫细胞内叶绿体数增加.     

高产酸性蛋白酶菌株的选育及酶学性质研究

以从酱醅中分离出的菌株JL-335为出发菌,采用紫外线诱变,结合HE值及酶活力检测,筛选出1株高产稳定的酸性蛋白酶菌株SKY-520。诱变条件:紫外灯功率20 W,距离25cm,诱变时间0(对照),1,3,5min。试验结果表明:20 W紫外灯,25cm照射,3min时致死率为74.3%,此时间为最佳照射时间;并且优化发酵条件,温度为28℃,pH为5.0,时间为48h,其产酶能力由847.2U/mL提高到3000.8U/mL,提高率将近254.2%;连续6次继代培养,遗传性状稳定。采用单因素试验、正交试验等手段考察了温度、pH值、金属离子等对所产酸性蛋白酶的酶学性质的影响,得出该酶的最佳作用条件为45℃、pH 3.5、添加Mn~(2+),此时酶活性可以提高183.7%,并且该酶在80℃下保温10min仍保留有74.2%的相对酶活,说明其具有一定的耐干热处理能力。     

两种冷却方式对宰后成熟过程中牛肉保水性的影响

通过对牛背最长肌施以常规冷却和快速冷却处理,研究不同冷却方式对宰后成熟过程中牛肉保水性的影响。结果发现快速冷却使蛋白性质在宰后12 h内变化不显著,使葡萄糖、乳酸含量及糖酵解潜力出现峰值时间提前,且肌原纤维蛋白疏水性、浊度及乳化性变化是宰后48 h至72 h蛋白结合水的能力减弱。此外,快速冷却比常规冷却处理牛肉的表观持水力在宰后6 h内较高、48 h后较低;宰后168 h滴水损失和蒸煮损失分别降低0. 11%和4. 37%,且差异极显著(p 0. 01),加压损失降低2. 07%(p 0. 05)。结果表明,快速冷却可在一定程度上提高原料肉质量,缩短僵化时间,提高保水性。     

高大毛霉液体发酵培养基的优化及产酶特性研究

采用正交实验确定高大毛霉(MHC-7)最佳发酵培养基组成为:黄豆粉3%、可溶性淀粉0.4%、硫酸镁0.2%、磷酸二氢钾0.2%、蔗糖0.3%和黄泔水.通过对MHC-7胞内蛋白酶、α-淀粉酶、α-半乳糖苷酶、谷氨酰胺酶、纤维素酶、脂肪酶活力测定,结果表明,产蛋白酶、α-淀粉酶、α-半乳糖苷酶和谷氨酰胺酶的峰值时间分别是36、48、42、48h,纤维素酶和脂肪酶在72h内酶活力一直呈上升趋势.     

常压室温等离子体诱变(ARTP)及高通量筛选高产蛋白酶米曲霉的初探

为提高酱油发酵菌种米曲霉的蛋白酶活力,采用实验室保藏菌种H0米曲霉为诱变出发菌株,对H0菌株进行常压室温等离子体诱变(ARTP),诱变条件:功率120 W;气流量10L/min;10个时间梯度处理。结果表明:当诱变时间为140s时,致死率接近90%,此时为最佳诱变时间。利用大豆球蛋白作为选择培养基关键因子进行初筛和96孔板高通量复筛,选出3株高蛋白酶活力菌株H5,H12,H15,并且经过福林酚法验证。最终筛选出米曲霉菌株H15具有高蛋白酶活力:酸性、中性、碱性蛋白酶活力分别为192.35,1816.31,3774.82U/g,比出发菌株H0分别提高17.49%,19.08%,10.66%。     

利用苹果渣发酵生产L-苹果酸工艺研究

以苹果渣为原料,经过去毒处理,在50L发酵罐中液体深层发酵生产L-苹果酸.研究了发酵过程中通气量、温度,以及搅拌转速等因素对苹果渣转化率、L-苹果酸产率的影响.结果表明,液体深层发酵生产L-苹果酸的最佳发酵工艺条件为:苹果渣浓度6%,发酵前期通气量(V/V)1:0.15(发酵48h前)～1:0.4(发酵48h后),温度30"C(发酵48h前)～28℃(发酵48h后),初始pH6.0～6.2,发酵周期108～120h,搅拌转速90r/min,苹果渣的平均转化率66.67%,平均产L-苹果酸40g/L.     

常温常压等离子体诱变选育高产L-异亮氨酸谷氨酸棒杆菌

以谷氨酸棒杆菌（Corynebacterium glutamicum）23798为原始菌株,对其进行常温常压等离子体（ARTP）诱变,以磺胺胍抗性和氨基酸与茚三酮特异显色为筛选标记,以期得到高产L-异亮氨酸的诱变谷氨酸棒杆菌,并对其遗传稳定性进行研究。结果表明,原始菌株23798经过ARTP诱变处理180 s后,经0.4 mg/mL磺胺胍抗性筛选、多孔板高通量筛选、发酵培养复筛,选育出一株高产L-异亮氨酸诱变谷氨酸棒杆菌（Corynebacterium glutamicum）B1。该菌株在摇瓶中发酵培养48 h,L-异亮氨酸产量达18.5 g/L,比原始菌株提高62.03%,且遗传性状稳定。     

甘蓝型油菜小孢子离体培养条件改良

应用低含油量甘蓝型油菜品系1064与高含油量品系H105杂种F1花蕾进行小孢子培养,研究了两个种植地点的油菜小孢子产胚率的影响。对长度在0.4cm～0.6cm,0.6cm～0.8cm以及0.8cm以上的胚分别培养,并比较了秋水仙碱悬浮处理离体小孢子、浸根和滴芽3种染色体加倍方法的加倍效率。结果表明,种植在西宁的材料小孢子产胚率比南京高,为8.6枚/皿;0.6cm～0.8cm大的胚转接到B5固体培养基,其成苗率高达48.53%;3种加倍处理方法中以50mg/L秋水仙碱悬浮小孢子48h染色体加倍效率最高,达到46.23%。本研究构建了含有123个株系的DH群体,可用于油菜含油量性状的QTL分析。     

浸泡液对糙米发芽的影响研究

发芽糙米是近一年兴起的一种新型保健食品,本实验重点研究了不同浸泡液对糙米发芽情况的影响。结果显示:较低浓度双氧水(H2O2)具有促进糙米发芽和增加芽长的作用,其中浓度为0.3%时,作用效果最显著(p<0.05)。针对不同种类的浸泡液(分别为:55.5mg/LCaCl2溶液、3%乙醇溶液、0.02mg/L赤霉素溶液、3%双氧水溶液和去离子水)的研究结果显示,在糙米发芽初期,0.3%的H2O2较其它浸泡液更能促进糙米发芽,缩短萌芽时间;在发芽48h后,经不同浸泡液处理的糙米,发芽率无显著差异。     

灵芝原生质体化学诱变育种

分别采用氯化锂、甲基磺酸乙酯(EMS)、亚硝酸诱变灵芝原生质体,对高产胞外多糖的菌株进行筛选。结果表明,氯化锂最佳诱变剂量为0.03%,此时诱变株L31胞外多糖产量最高为19.99 mg/mL,较原发菌株提高914.72%;EMS最佳诱变剂量为0.12%,此时诱变株E40胞外多糖产量最高为6.14 mg/mL,较原发菌株提高211.68%;亚硝酸最佳诱变时间为15 min,此时诱变株H48胞外多糖产量最高为10.13 mg/mL,较原发菌株提高414.21%;3种诱变方式下,诱变株L31的胞外多糖产量最高,且遗传性状最稳定,第三、五、七、九代胞外多糖产量较原发菌株分别提高了738.58%、671.07%、683.25%、673.10%。     

云烟 87 八倍体植株的诱导及其主要生殖特征

通过不同浓度秋水仙素溶液浸泡"云烟 87"四倍体无菌苗茎尖 72 h,经组织培养,成功获得八倍体植株,其中以 0.4%浓度秋水仙素处理检出率最高,为 28.57%。与"云烟 87"四倍体植株相比,八倍体植株花器官明显较大,叶片较厚、较小,节间较短。八倍体植株花粉量小,花粉大小不均一,可见超大花粉,花粉萌发率低,仅为 6.45%。八倍体自交不能结实,但与四倍体烟草品种杂交均可获得大量有活力的种子,发芽率均大于 65%,且与同"云烟 87"四倍体杂交不能获得种子的野生烟草Nicotiana plumbaginifolia杂交也可获得有活力的种子。可见,通过秋水仙素浸泡结合组织培养获得烟草八倍体是可行的。      

酯化红曲霉原生质体制备及紫外线诱变育种

以红色红曲霉（Monascus ruber）为出发菌株,用混合酶制取原生质体并对原生质体形成条件进行探讨,并进行紫外诱变选育。采用50h菌龄的菌丝体,使用蜗牛酶（0.6%）＋溶菌酶（0.4%）＋纤维素酶（0.6%）的复合酶液,30℃酶解2h,在该条件下原生质体浓度可达7.8×106个/mL,再生率为7.3%。在最佳紫外照射时间80s下,突变株经筛选,得到一株酯化酶活显著提高、遗传性能稳定的诱变株HN215-6,其酶活达468.4mg/100mL,比出发菌株HN215提高了1.66倍。     

氮气气调胁迫对锈赤扁谷盗种群适合度的影响

为了解不同氮气浓度处理对锈赤扁谷盗Cryptolestes ferrugineus (Stephens)种群适合度的影响,本研究采用构建生命表的方法,研究了95%和98%两种氮气浓度胁迫24 h后锈赤扁谷盗试验种群的生长发育情况,并以此分析了不同氮气浓度对锈赤扁谷盗各生命参数和种群适合度的影响。结果显示,与对照组相比：95%氮气浓度处理后,子代锈赤扁谷盗的孵化率、化蛹率、羽化率均呈现下降的趋势,分别下降了2.00%、11.34%、8.80%,卵、幼虫、蛹及总发育历期分别延长了0.2 d、2.0 d、0.4 d、2.6 d：98%氮气浓度处理后,子代锈赤扁谷盗的孵化率、化蛹率、羽化率均呈现下降的趋势,分别下降了6.00%、25.33%、13.51%,卵、幼虫、蛹及总发育历期分别延长了0.4 d、4.3 d、1.0 d、5.8 d。此外,氮气气调胁迫导致处理当代锈赤扁谷盗单雌产卵量显著减少,子代雌虫占比升高,但子代单雌产卵量未受到影响。本研究分析了氮气气调胁迫对锈赤扁谷盗种群适合度的影响,为氮气气调防治储藏物害虫提供了参考依据。     

Effects of passive immunization of goats against inhibin on follicular development,hormone profile and ovulation rate

This study was conducted to investigate the effect of immunoneutralization against endogenous inhibin on FSH secretion and ovulation rate, with the aim of developing a new superovulation method using inhibin antiserum in goats. Two groups of goats received an i.v. injection of either 10 ml normal goat serum (control; n = 6) or 10 ml inhibin antiserum developed against [Tyr(30)]-inhibin alpha (1-30) (n = 6) 48 h before treatment with prostaglandin F(2alpha) (PGF(2alpha)). Blood samples were collected at 6 h intervals and ovaries were examined each day using a B-mode ultrasound scanner equipped with a 7.5 MHz transducer during the experimental period. Immunization against inhibin resulted in a four- to fivefold increase (P < 0.01) in plasma concentrations of FSH. After luteolysis, plasma concentrations of oestradiol increased markedly to reach a preovulatory peak, which was about two times higher (P < 0.01) than that of the controls. The treatment was accompanied by a significant increase in the total number of follicles of > or = 3 mm in diameter at 24 (8.2 +/- 0.4 in inhibin antiserum group versus 4.8 +/- 0.3 in control group) and 96 h later (13.5 +/- 1.0 in inhibin antiserum group versus 5.3 +/- 0.6 in control group). The ovulation rate was significantly (P < 0.01) higher in goats treated with inhibin antiserum (4.2 +/- 0.5; n = 6) than in control goats (1.8 +/- 0.3; n = 6). These results indicate that inhibin is an important factor in the regulation of FSH secretion in goats and demonstrate that passive immunization against inhibin at 48 h before treatment with PGF(2alpha) induces the development of more follicles and increases ovulation rate. Thus, inhibin antiserum treatment may be an alternative to the use of exogenous gonadotrophins for induction of superovulation in goats.     

玉米芯载体固定化米根霉发酵L-乳酸工艺的研究

对玉米芯载体固定化米根霉R-1发酵L-乳酸的工艺条件进行研究。结果表明:玉米芯与葡萄糖的添加比例为1∶4,经L9(34)的正交设计优化,(NH4)2SO4、KH2PO4、Mg-SO4、ZnSO4质量浓度分别3,0.3,0.4,0.2g/L,经48h发酵,L-乳酸积累量达到32.23g/L,葡萄糖对L-乳酸转化率达80.58%。     

Validity of prepartum changes in vaginal and rectal temperature to predict calving in dairy cows

The prevalence of dystocia is high in many dairy herds and is associated with stillbirth and negative effects for the cow. An accurate predictor of calving would enable supervision of cows more precisely to a relevant time interval so that obstetrical assistance can be provided in a timely manner. This might help to decrease calf mortality rate. Evidence exists that cows exhibit a decrease in body temperature before the onset of calving. The performance of a decrease in body temperature as a test to predict the onset of calving in dairy cows has not been investigated. The objective was to investigate test criteria of a decrease in vaginal and rectal temperature as predictors of calving in dairy cows. In 3 experiments, temperature loggers (Minilog 8, Vemco Ltd., Halifax, Canada) were inserted into the vagina of cows before calving (n = 85), and rectal temperatures were measured twice daily in 55 of these cows. Vaginal temperatures were 0.2 to 0.3°C and 0.6 to 0.7°C lower on the day of calving compared with 24 and 48 h before calving, respectively. Rectal temperatures were 0.3 to 0.5°C and 0.4 to 0.6°C lower on the day of calving compared with 24 and 48 h before calving, respectively. Vaginal temperatures exhibited a diurnal rhythm during the 120 h before calving, which continued on a lower level during the 48 h preceding parturition. In the 3 experiments, a decrease in vaginal temperature of ≥0.3°C over 24 h could predict calving within 24 h, with sensitivity ranging from 62 to 71% and specificity ranging from 81 to 87%. Similarly, a decrease in rectal temperature measured at 0730 h of ≥0.3°C could predict calving within 24 h, with sensitivity from 44 to 69% and specificity from 86 to 88%. Although dairy cows exhibit a distinctive decrease in vaginal and rectal temperatures commencing approximately 48 h before calving, detecting this decrease does not determine the onset of calving precisely. Nevertheless, it can provide valuable information in addition to the traditional signs (i.e., relaxation of the sacrosciatic ligament) that calving is imminent.     

鲜湿米粉品质改良研究

鲜湿米粉是我国南方的传统米制主食,属于高含水量产品,在实际加工过程中,品质较难保证。选择以马铃薯变性淀粉、焦磷酸钠、卵磷脂、海藻酸钠作为鲜湿米粉加工中的品质改良剂,以鲜湿米粉蒸煮损失率及感官评价为指标,比较上述4种品质改良剂不同添加量对鲜湿米粉的品质影响。以此为基础设计正交实验,发现在添加马铃薯变性淀粉5%(干物质质量分数,下同)、焦磷酸钠0.4%、卵磷脂0.4%、海藻酸钠0.3%时,鲜湿米粉蒸煮损失率为1.3%,感官评分为91.4分,在同等条件下达到最佳。然后,以断条率、蒸煮损失率、透色比、糊化度为指标,未添加品质改良剂的鲜湿米粉为对比样,以单因素实验中最适添加量添加品质改良剂制作鲜湿米粉、正交实验中最佳复合添加量添加品质改良剂制作鲜湿米粉,进行对比实验。以最佳添加量添加复合品质改良剂制作的鲜湿米粉断条率降低到1.7%,蒸煮损失率降低到1.3%,透射比提高到0.836,糊化度提升到92.1%,在对比实验中品质改良效果最佳。