小麦秸秆静态高温堆腐过程中的理化特征

为了解小麦秸秆堆肥过程中的生物化学特征,进行了高温好氧堆肥试验.结果表明,添加复合微生物腐解菌剂处理较不添加复合微生物腐解菌剂(CK)升温快,温度高,高温持续时间长;堆腐第2d添加菌剂处理堆体温度上升到50℃以上,第3 d达到最高温度67.1℃,50℃以上持续6 d;CK堆腐第3 d达到50℃,第4 d达最高温度59.5℃,50℃以上持续5 d.堆腐第9 d添加菌剂处理E4/E6值达高峰值3.419,CK的达高峰值4.085,堆腐第23 d后添加菌剂处理的胡敏酸E4/E6值为1.512～1.709,而CK处理的E4/E6值为1.649～2.060,堆腐过程添加菌剂处理的E4/E6值一直低于CK,表明添加菌剂能促进腐殖质的缩合和芳构化.堆肥腐熟后pH值较堆制前有所提高,添加菌剂处理的pH值相对较低,变化幅度较小.加入微生物菌剂处理的电导率(EC)值较高,且在持续高温阶段高于后熟阶段.     

对羟基苯甲酸胁迫下尖孢镰刀菌侵染草莓根系的组织结构观察

以‘丰香’（Toyonoka）和‘土特拉’（Tutela）草莓品种为试材,利用石蜡切片技术研究了在自毒物质对羟基苯甲酸胁迫下,尖孢镰刀菌草莓专化型（Fusarium oxysporum f. sp. fragariae）侵染根系引起的组织结构变化。结果表明：对羟基苯甲酸胁迫下,尖孢镰刀菌菌丝在‘丰香’和‘土特拉’根系中的侵染速率明显加快,对根系表皮、皮层、中柱薄壁细胞及导管壁结构的破坏程度也明显加重,且对‘丰香’的破坏程度明显重于‘土特拉’。对羟基苯甲酸胁迫显著提高了‘丰香’和‘土特拉’根系组织含菌丝导管的比例,分别为22.5%和15.8%;但‘土特拉’根系含胶状物导管的比例为26.3%,明显高于‘丰香’（16.3%）。在对羟基苯甲酸胁迫下,‘土特拉’根系组织产生胶状物比‘丰香’早。‘土特拉’单独接菌处理根系内含有侵填体导管的比例为1.6%,明显高于‘丰香’单独接菌处理和对羟基苯甲酸胁迫下‘土特拉’接菌处理（1.0%和1.2%）。对羟基苯甲酸胁迫下接种尖孢镰刀菌可明显加重草莓根系组织受损程度,且‘丰香’枯萎病发生较重。     

硫酸氘制剂对淡水浮游藻类生物量影响的研究

以多种淡水浮游绿藻的混合藻种为培养对象,在人工培养液中添加不同含量的硫酸氘(D2SO4)制剂进行培养,通过测定藻液光密度(OD)值研究了不同浓度D2SO4制剂对淡水浮游藻类生物量影响的效果。结果显示:(D2SO4)制剂在9~20℃温度条件下能促进淡水浮游藻类生物量的增加。在重氢OPAL723TM试验中,浓度0.2‰组藻类增加最多,其结果与对照有显著差异(P(0.05),与0.05‰组和0.001‰组差异不显著(P>0.05);在重氢511T试验中,浓度1‰组藻类增加最多,其他组随浓度降低藻类增加量相应减少。     

Origin of Clostridium perfringens isolates determines the ability to induce necrotic enteritis in broilers

Since the ban on growth-promoting antibiotics in animal feed in the European Union, necrotic enteritis has become a major cause of mortality in broiler chickens. Despite the importance of the disease, the pathogenesis is still not completely understood. In the current study, Clostridium perfringens strains isolated from healthy flocks and isolates from outbreaks of necrotic enteritis were evaluated for the ability to cause gut necrosis in an intestinal loop model in laying hens and in an experimental infection model in broilers. High, intermediate and low alpha toxin producing strains were chosen from each isolation source. Only the isolates from field outbreaks induced necrotic gut lesions, independent of the amount of alpha toxin produced in vitro. It was also shown that alpha toxin producing isolates from calf hemorrhagic enteritis cases were not able to induce necrotic enteritis in poultry. These results suggest the presence of host specific virulence factors in C. perfringens strains, isolated from chickens with intestinal necrotic enteritis lesions.     

超甜玉米新品种甘甜4号的选育

甘甜4号是以J甜26作母本,以J甜11作父本配制而成的超甜玉米一代杂种。株高177cm,穗位高65cm,抗倒伏,持绿性好,适应性广,品质优良,果穗柱形,苞叶包被完整,籽粒排列整齐,鲜出籽率69.9%,粒长1.1cm,适于加工削粒或鲜穗上市销售。一般每667m2产鲜果穗900kg左右,出苗到鲜穗采收85d(天)左右,适宜西北春玉米区种植。     

双向选择对团头鲂生化遗传变异的影响↑（*）

本文报导双向选择对团头鲂生化遗传变异的影响。试验材料鱼包括来自淤泥湖的原种，１９８６－１９９４年群体选育的第四代（“选育 Ｆ４”），以及１９９１、１９９４年连续兄妹杂交的第二代（“近交Ｆ２”）。计检测了８种同工酶，１９个位点。三群体的多态座位比例一致（５．２６％），但平均杂合度趋异。“选育Ｆ４”平均杂合度最高（０．０２１３），“近交Ｆ２”最低（０．０１７４）。经４代选育，平均杂合度增加４％，而经２代近交，平均杂合度降低１５％。     

Effects of aromatase inhibitors on reproduction in male three-spined sticklebacks, Gasterosteus aculeatus, exposed to long and short photoperiods

Three-spined stickleback Gasterosteus aculeatus, males were implanted with Silastic capsules filled with different aromatase inhibitors; 1,4,6-androstatriene-3,17-dione or the non-steroidal CGS16949 A, 4-(5,6,7,8-tetrahydrimidazol [1,5-a]pyridin-5-yl) benzonitrile monohydrochloride or empty capsules. The fish were then exposed to long or short photoperiod. Under the long photoperiod most fish in all treatments displayed a hypertrophied kidney (a secondary sexual character in sticklebacks) and completed, quiescent spermatogenesis, similar as in the natural spawning period. Under the short photoperiod the controls had unstimulated kidneys and an active spermatogenesis, whereas the males implanted with both aromatase inhibitors had stimulated kidneys, though not to the extent as in the long photoperiod, and completed, quiescent spermatogenesis. These findings suggest that aromatization is of importance for the inhibitory effects of short photoperiod on reproduction in the stickleback. This revised version was published online in July 2006 with corrections to the Cover Date.     

脂多糖对大黄鱼原代头肾巨噬细胞的激活作用

为了揭示硬骨鱼C型凝集素受体 (C-type lectin receptor,CTLR)的生物学功能,实验以从大黄鱼转录组数据库中筛选出的一个CTLR基因—C型凝集素结构域家族4成员E基因 (Clec4e)为研究对象,研究其分子特征、表达分布和凝集特性。结果显示,LcClec4e cDNA全长1 546 bp,开放阅读框 (ORF)771 bp,编码254个氨基酸。LcClec4e的N端有一个跨膜区,无信号肽,C端含有一个糖识别结构域 (CRD),其中含有糖结合位点EPN和WFD以及6个可形成二硫键的保守半胱氨酸。系统发育分析表明,LcClec4e与多种鲈形目鱼类Clec4e具有较近的亲缘关系。荧光定量PCR结果显示,LcClec4e在所检测的10种组织中呈组成型分布,且在肝脏中表达量最高;LcClec4e在来源于大黄鱼头肾组织的原代巨噬细胞、淋巴细胞和粒细胞中均有表达,且在巨噬细胞中表达量最高;经灭活溶藻弧菌刺激后,LcClec4e在3种免疫细胞中的表达均极显著上调。原核表达的重组LcClec4e胞外段 (recombinant LcClec4e-extracellular domain,rLcClec4e-ex)具有Ca²⁺依赖性的凝集活性,可凝集小鼠、家兔的红细胞,以及嗜水气单胞菌、变形假单胞菌、溶藻弧菌和坎氏弧菌等4种水产常见的革兰氏阴性菌。D-葡萄糖、D-果糖、D-甘露糖、D-麦芽糖、α-乳糖和脂多糖均可抑制rLcClec4e-ex对大黄鱼重要病原菌变形假单胞菌的凝集作用,说明LcClec4e可能与变形假单胞菌表面的糖类物质结合。上述结果提示,LcClec4e可能作为一种模式识别受体,通过结合病原菌表面的糖类病原体相关分子模式来识别病原,参与大黄鱼抗细菌感染的免疫防御。

     

施氮量对橡胶园土壤铵态氮和硝态氮垂直分布的影响

以尿素为氮源,研究不同施肥量对土壤中铵态氮和硝态氮垂直分布的影响。结果表明：施肥可显著增加0～40cm土壤中铵态氮和硝态氮的含量;当施肥量超过0．6kg／株时,增加施肥量不会显著增加0～40cm土壤中铵态氮和硝态氮的含量;施肥量越大,淋溶到80～100cm土层土壤的铵态氮和硝态氮的量越大。