Analysis of leaf and needle litter decomposition by differential scanning calorimetry and differential thermogravimetry

Summary Changes in the physicochemical properties of three kinds of litter (Prunus serotina leaves, Carpinus betulus leaves, and Pinus sylvestris needles) were analyzed by differential scanning calorimetry and differential thermogravimetry after decomposition for 12 to 27 months under field conditions. As expected, holocellulose was always decomposed to a larger extent than the corresponding lignin components, leading to an enrichment of lignin in the residue. These lignins were more or less modified depending on the plant species. Moreover, the results suggest that energy-rich crystalline cellulose accumulates during decomposition at the expense of easier degradable amorphous cellulose and hemicelluloses. The quotient Q, from the corresponding calorimetry and thermogravimetry values, was introduced to estimate the specific energy content as a measure for the decomposition of litter components.Dedicated to the late Prof. Dr. W. Kühnelt     

~(60)Coγ射线辐照对苹果保鲜作用的研究

用~(60)Coγ射线辐照黄香蕉苹果,研究结果表明,0.3—0.5kGy的辐照剂量有利于苹果的贮藏,该剂量范围对苹果的主要营养成分糖、Vc和苹果酸的含量损失不大,但对贮藏期间苹果的吸呼强度和乙烯的产生有一定的抑制作用,0.5kGy的辐照剂量可以杀死97％以上的轮纹病原菌。     

中蜂和意蜂工蜂蛹期呼吸代谢的比较

中华蜜蜂和意大利蜜蜂工蜂蛹期呼吸商 (RQ)分别为 (0 .798± 0 .0 5 2 )和 (0 .84 6± 0 .0 39) .意蜂工蜂蛹期单位体重耗氧量和 CO2 释放量明显高于中蜂 ,3日龄后两者都随蛹期日龄增长而明显上升     

Vaccination of Plasmid DNA Encoding Somatostatin Gene Fused with GP5 Gene of Porcine Reproductive and Respiratory Syndrome Virus Induces Anti-GP5 Antibodies and Promotes Growth Performance in Immunized Pigs

Somatostatin （SS） is a hormone that inhibits the secretion of growth hormone. Immunization against SS can promote the growth of animals. This paper described the effects of DNA immunization on the growth and antibody response in mice and pigs immunized with a plasmid DNA encoding SS fused with GP5 of porcine reproductive and respiratory syndrome virus （PRRSV）. A fragment of 180 bp encoding partial SS gene was amplified by PCR from the genomic DNA of peripheral blood mononuclear cells of pigs, and cloned as a fusion gene with PRRSV GP5 in plasmid pISGRTK3. Three times of immunization with the resulting plasmid pISG-SS/GP5 induced anti-GP5 antibodies in BALB/c mice and pigs, as demonstrated by GP5-specific ELISA and immunoblotting. Compared with pigs immunized with empty vector pISGRTK3, the growth performance of pigs immunized with pISG-SS/GP5 was increased by 11.1% on the 13th week after the last vaccination. The results indicated the plasmid DNA encoding SS and PRRSV GP5 fusion gene elicited anti-GP5 antibodies and improved the growth performance of immunized pigs.     

猪呼吸道疾病(PRDC)的综合防治

介绍了猪呼吸道病综合征的发病原因、症状、病变、预防和治疗措施。     

不同呼吸抑制剂对小麦幼苗根系硝酸还原酶活性的影响

为了从生理学角度阐明硝酸还原酶活性(NRA)和呼吸作用的关系,在水培条件下,研究了三羧酸循环的抑制剂之一丙二酸(C3H4O4)、呼吸链抑制剂叠氮化钠(NaN3)、呼吸链解偶联剂2,4-二硝基苯酚(DNP)以及质膜H+-ATPase抑制剂钒酸钠(Na3VO4)对小麦幼苗根系硝酸还原酶活性(NRA)的影响。结果表明,当丙二酸浓度由0增加到1.0 mmol/L时,NRA直线下降,而当丙二酸浓度由1.0 mmol/L再增加到5.0 mmol/L时,NRA几乎保持不变;当NaN3浓度由0 mmol/L增加到1.0 mmol/L时,NRA近直线下降,当NaN3浓度由1.0 mmol/L增加至5.0mmol/L时,NRA下降趋势趋于平缓;在试验浓度范围内,呼吸链解偶联剂2,4-二硝基苯酚对NRA几乎无影响;质膜H+-ATPase的专一抑制剂钒酸钠也对NRA有抑制作用,当Na3VO4浓度由0增加到0.5 mmol/L时,NRA呈直线下降,后随Na3VO4浓度的继续升高,NRA总体呈下降趋势,但下降幅度较为平缓。小麦根系NRA活性依赖于根系呼吸作用的顺利进行,同时也对质膜H+-ATPase有依赖作用。     

烟草种子萌发过程中呼吸强度与过氧化物酶活性变化研究*

 为探明烟草种子萌发过程中，呼吸强度与过氧化物酶活性的变化，用滤纸床播种，人工气候箱中在25～28℃的条件下培养。采用滴定和比色方法对烤烟K326和白肋烟TN86种子萌发过程中，分时期测定其呼吸强度与过氧化物酶活性变化。结果表明：（1）K326种子的呼吸强度在108h时达最大值3.483mg CO₂/（gDW·h），TN86种子的呼吸强度在132h时达最大值3.067mg CO₂/（gDW·h）。（2）K326和TN86干种子中过氧化物酶活性极低；至萌发结束时，K326和TN86种子中过氧化物酶活性都达最高，较种子吸涨前增加了51.1倍和42.1倍。（3）种子在萌发期间，呼吸强度与过氧化物酶活性呈显著正相关。     

猪繁殖与呼吸综合征病毒灭活疫苗安全性和免疫原性测定

选用猪繁殖与呼吸综合征病毒福建分离株(PRRSV Fuzhou 01株)为制苗种毒。病毒经Marc 145细胞增殖、超速离心浓缩、甲醛灭活后,分别制成新型佐剂IMS1312灭活疫苗和油乳剂灭活疫苗,两种疫苗病毒含量约为108.0TCID50.mL-1。30头25日龄的PRRSV抗体阴性的断奶猪被随机分成5组,每组6头,用于检测疫苗的安全性和免疫原性。结果表明两种疫苗首次免疫断奶仔猪后14 d可以检测到抗体,二免14 d抗体水平达到高峰,一免180 d后抗体水平可以维持在1∶320。两种佐剂苗在4℃放置12个月均不分层,并对断奶仔猪具有良好的安全性和免疫原性。     

RT-PCR技术检测猪繁殖与呼吸障碍综合征病毒(PRRSV)

根据猪PRRSV的ORF7基因序列,设计并合成了1对引物,以PRRSV RNA为模板,筛选最佳反应条件,建立了检测PRRSV的RT-PCR方法。应用该方法对病毒细胞培养物进行基因扩增,均获得了分子量为443bp的特异性目的片段,而对PCV2、PRV、CSFV及Marc-145细胞进行同条件检测,结果均为阴性;PRRSV扩增产物测序结果与文献报道的PRRSV其他毒株序列同源性达92%~98%。敏感性试验表明,该体系可检测到2.39TCID50的PRRSV;对2004~2005年送检的81份临床样品进行检测,阳性率为23.4%。上述研究结果表明,建立的RT-PCR特异性好、敏感性高,可用于猪繁殖与呼吸综合征的诊断和流行病学调查。     

沈阳地区鸡慢性呼吸道病的流行病学调查

采用玻片凝集试验结合现场观察，对沈阳地区15个鸡场不同品种和日龄的未免疫鸡进行了鸡慢性呼吸道病(CRD)流行病学调查。共检测了300份鸡血清，平均阳性率33％。被调查的15个鸡场中的12个鸡场显示有CRD血清抗体阳性鸡，表明沈阳地区一些鸡场鸡群已被鸡败血霉形体(MG)感染，有的鸡场还相当严重。