金沙江干热河谷植物叶片元素含量在地表凋落物周转中的作用     

闫帮国  纪中华  何光熊  史亮涛  潘志贤  李纪潮  岳学文  王春雪  彭辉 《勤云标准版测试》2013,33(18):5668-5674

叶片的化学计量学特征在植物响应环境变化,决定植物的生后效应中具有重要的偶联作用。为了阐明植物叶片生源要素含量对凋落物周转的影响,分析了金沙江干热河谷萨瓦纳草地生态系统植物叶片的化学计量学特征与凋落物周转时间的关系。结果显示:凋落物周转受到多重生源要素及其交互作用的影响,其中K与凋落物周转时间存在显著的正相关关系,而S、Mn、Mg元素具有负关系,表明K可能抑制凋落物的分解,而S、Mn、Mg元素可能会促进凋落物分解。在物种水平上K、S、Mn分别与凋落物周转时间存在显著的相关性, K、S组合解释了16.93%的凋落物周转时间变异;样方水平上,K、S、Mn、Mg分别与凋落物周转时间具有显著相关性,虽然N对凋落物的周转时间影响不显著,但当N与K及其交互作用对凋落物周转时间解释了37.42%的变异。其它元素组合也可在不同程度上解释了凋落物周转时间的变异。多元要素的互作效应表明元素间可能存在拮抗和协同效应,凋落物分解过程中可能受到多重分解者的共同作用,而不同分解者会受到不同的元素限制。未来的研究应当注重N、P以外的元素在生物地球化学循环中的作用。  相似文献   

液质联用法检测禽蛋中氟苯尼考和氟苯尼考胺残留     

李雅宁  苏亚  郭林云 《畜牧与饲料科学》2020,41(3):76-79

建立了超高效液相色谱串联质谱法检测禽蛋中氟苯尼考和氟苯尼考胺残留物的方法。采用电喷雾离子源（ESI）、多反应监测（MRM）、正负离子模式同时扫描检测,内标法定量。禽蛋试样采用碱化乙酸乙酯和乙腈提取,正己烷萃取,LC/MS-MS分析。结果表明,该方法的检测限（LODs）为0.1 μg/kg,定量限（LOQs）为0.2 μg/kg。在0.2~200 μg/L范围内均呈良好线性关系,并且3个添加浓度的平均回收率范围为70%~110%,相对标准偏差（RSD）小于10%。该方法简便高效、准确可靠,可作为禽蛋中氟苯尼考和氟苯尼考胺残留的检测方法。  相似文献   

混合菌种发酵对草鱼肉微生物和生物胺变化的影响   总被引：1，自引：0，他引：1  

谢诚  刘忠义  周宇峰 《西北农林科技大学学报(自然科学版)》2010,38(3):167-172

【目的】研究发酵草鱼的pH值、微生物菌群以及生物胺等特性的变化,为发酵草鱼的加工及其卫生品质的控制提供参考。【方法】新鲜草鱼宰杀后,切取宽度3cm的草鱼鱼块,加入30g/kg食盐腌制6h后,混合接种酵母、红曲和乳酸菌,于30℃发酵12h,然后进行微生物检测,并用高效液相色谱检测生物胺的变化。【结果】经过12h的发酵,鱼肉中的组胺、酪胺、腐胺、亚精胺和精胺的含量分别为(0.29±0.10)、(1.31±0.10)、(16.53±0.20)、(3.86±0.15)和(5.18±0.2)mg/kg,明显低于对照组的(1.31±0.10)、(1.96±0.10)、(21.62±0.30)、(10.93±0.20)和(12.69±0.25)mg/kg;发酵鱼肉pH值从起始的6.4下降到5.2;大肠菌群最近似数300CFU/kg,没有检出芽孢菌。【结论】接种混合菌种于30℃发酵12h,可以控制发酵草鱼制品中组胺、酪胺、腐胺、亚精胺及精胺的含量,抑制大肠菌群的生长,保证发酵草鱼制品的卫生品质。  相似文献   

A Case of Olfactory Neuroblastoma Induced in A Rat by N-Nitrosobis(2-hydroxypropyl)amine     

Takagi M  Shiraiwa K  Kusuoka O  Tamura K 《Journal of toxicologic pathology》2010,23(2):111-114

N-nitrosobis(2-hydroxypropyl)amine (BHP) is a well-known carcinogen and induces tumors in various tissues. In the present paper, a case of olfactory neuroblastoma (ONB) induced in a rat by BHP is described. The tumor was observed in one out of 25 male rats that received 2000 ppm of BHP in drinking water from 6 to 18 weeks of age and were sacrificed at 26 weeks of age. Histologically, the tumor arose in the posterior nasal cavity and consisted of small round cells and elongate cells with scant basophilic cytoplasm. The neoplastic cells proliferated with compartmentalization into the lobules by fibrovascular septa. True rosettes, pseudorosettes and an intercellular fibrillar matrix were occasionally observed. Immunohistochemically, the tumor cells were positive for NF120/200 and β III-tubulin. These results indicate that the present tumor is the first case of ONB induced in a rat by BHP treatment.  相似文献   

No Mutations of Lysophosphatidic Acid Receptor Genes in Lung Adenocarcinomas Induced by N-Nitrosobis(2-hydroxypropyl)amine in Rats     

Wakabayashi N  Tsujino M  Tajiri M  Taki M  Koshino A  Ikeda H  Fukushima N  Tsujiuchi T 《Journal of toxicologic pathology》2010,23(1):63-66

Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation and migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, frequent mutations of the LPA receptor-1 (LPA1) gene were detected in rat lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP). In this study, to evaluate the involvement of other LPA receptor gene alterations during lung carcinogenesis, we investigated mutations of the LPA2, LPA3, LPA4 and LPA5 genes in lung adenocarcinomas induced by BHP in rats. Fifteen male Wistar rats, 6 weeks of age, were given 2000 ppm BHP in their drinking water for 12 weeks and then maintained without further treatment until sacrifice at 25 weeks, and 15 adenocarcinomas were obtained. Genomic DNAs were extracted from frozen tissues, and the LPA2, LPA3, LPA4 and LPA5 genes were examined for mutations, using polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. No mutations of LPA2, LPA3, LPA4 and LPA5 were detected in the 15 adenocarcinomas. These results suggest that alterations due to LPA2, LPA3, LPA4 and LPA5 gene mutations might not be involved in the development of lung adenocarcinomas induced by BHP in rats.  相似文献   

Essay of Different Extraction Procedures in Capelin Fish Meal for Biogenic Amine Determination by HPLC     

Claudia Ruiz-Capillas  Mehdi Triki  Cristina de las Heras  Margarita Tejada  Heiða Pálmadóttir  Rósa Porvaldsdóttir 《Journal Of Aquatic Food Product Technology》2013,22(5):443-453

This study assesses the effects of different extraction procedures of biogenic amines in capelin fish meal with different concentrations of trichloroacetic acid (TCA) for their determination by high performance liquid chromatography (HPLC). No significant differences were noted between the use of TCA at 7.5 and 10% for the extraction of biogenic amines in E1 and E3 extraction, except for tyramine. The extraction using 7.5% TCA in one step and centrifugation (E1) was a simple and rapid method. This extraction seems to be the most suitable for the extraction of amines in these kinds of samples, compared to the other methods tested. The biogenic amine that presented the highest levels in the fish meal studied was cadaverine (208–226 mg/kg), followed by putrescine and histamine (164–173 and 44–46 mg/kg, respectively). Biogenic amine levels were low when compared to the toxic levels observed in these kinds of products.  相似文献   

Quality Indices of Cooked Southern King Crab (Lithodes santolla Molina, 1782) Meat During Storage at 0 and −20°C     

Susana J. Risso  Amalia A. Carelli 《Journal Of Aquatic Food Product Technology》2013,22(7):1120-1131

ABSTRACT

The aim of this work was to determine the changes in quality of cooked southern king crab (Lithodes santolla) meat during storage at 0°C for 5 and 10 days and ?20°C for 10, 30, 60, and 90 days. Chemical indices varied from the initial to the final storage time in refrigerated and frozen samples as follows: TVB-N, 15.8–29.2 and 15.8–23.2 mg/100 g; TMA, 0.0–8.3 and 0.0–1.2 mg/100 g; formaldehyde, 0.5–8.6 and 0.5–3.7 mg/kg; indole, 3.3–20.7 and 3.3–6.6 µg/100 g; lactic acid, 16.4–39.1 and 16.4–16.6 mg/100 g; and P ratio, 0–28.4 and 0–5.2%, respectively. The total nucleotide content rendered 6.77 µmol/g, with adenosine monophosphate (AMP) the main component. The nucleotide indices varied in refrigerated and frozen samples as follows: K, 7.37–27.5 and 7.37–10.3%; Ki, 58.3–86.5 and 58.3–82.7%; H, 30.2–54.9 and 30.2–38.0%; G, 19.4–57.8 and 19.4–15.8%; P, 17.2–42.3 and 17.2–14.7%; and Fr, 41.6–13.4 and 41.6–17.3%, respectively. Biogenic amines found at both storage temperatures were spermine, spermidine, tyramine, and agmatine. Spermine may be considered as a potential freshness index for refrigerated samples and spermidine for frozen storage. The tyramine level should be monitored. During the storage period tested, none of the chemical indices studied exceeded the legal limits.  相似文献   

Broad_scale,dense amphipod tube aggregations on the sea bed: implications for resource species that utilize benthic habitats     

JOSEPH VITALIANO  DAVID PACKER  VINCENT GUIDA 《Fisheries Oceanography》2013,22(1):61-67

During a research cruise to Georges Bank in 1999 to study the areas closed to fishing, broad areas of the sea floor (3000_km²) were found to have a high percentage cover of emergent invertebrate tubes. Most of these tubes were attributable to the tubicolous epifaunal amphipod, Ericthonius rubricornis. Our data show the spatial extent that dense clumps of amphipod tubes could cover the sea floor on Georges Bank. When some of the same sites were sampled 1_yr later, in June 2000, the percent cover of the tube clumps on the sea floor was significantly reduced. Biogenic structures, such as invertebrate tubes, are important features of benthic habitats and may provide protection for juvenile fish and invertebrate resource species. Our observations reiterate that biogenic habitat characteristics are not spatially and temporally stable and this needs to be recognized by fisheries managers when managing the living marine resources that utilize these habitats.  相似文献   

四种生物源农药对葡萄斑叶蝉的药效评价   总被引：1，自引：1，他引：0  

阿衣巴提·托列吾  张以和  潘卫萍  曾继勇  马德英 《新疆农业科学》2012,49(8):1461-1465

[目的]葡萄斑叶蝉是新疆葡萄生产上的重要害虫,以成、若虫群集于葡萄叶的背面,吸食汁液,使叶片正面呈现白色斑点,虫口密度大时整株叶片变为黄白色、焦枯并提前脱落严重影响葡萄产量和果实品质.结合新疆生产实际,筛选对葡萄斑叶蝉防效较好的生物源农药,为安全、高效治理葡萄斑叶蝉提供科学依据.[方法]选择四种生物药剂进行田间防治葡萄斑叶蝉的药效试验及评价.[结果]四种生物源农药对葡萄斑叶蝉防效顺序是0.3;印楝素乳油500倍最好,其次是艾绿士60 g/L悬浮剂(乙基多杀菌素)和云菊5;天然除虫菊素乳油,药剂持效期为7～9d.云菊5;天然除虫菊素乳油(1 200倍)、艾绿士60 g/L悬浮剂(乙基多杀菌素4 000倍)防治葡萄斑叶蝉具有较好的速效性和持效性,5d后的防效仍保持在64;～80;.[结论]四种生物源农药表现出了不同的速效性及持效性,可作为化学农药的替代产品,交替使用.  相似文献   

常见水产品中生物胺的调查及分析   总被引：1，自引：0，他引：1  

赵中辉  林洪  王林  李振兴 《水产科学》2012,31(6):363-366

为研究不同水产品中生物胺的产生情况,利用高效液相色谱-柱后衍生-荧光检测技术对蓝点马鲛、黄鳍金枪鱼、银鲑、牙鲆、中国明对虾、鹰爪虾、中华绒螯蟹、杂色蛤、杂色鲍中的7种生物胺含量进行调查与分析。试验结果表明,鲜活水产品中几乎不含生物胺,或仅含少量的精胺、亚精胺;腐败水产品中检出大量的生物胺,其中蓝点马鲛、黄鳍金枪鱼、银鲑、牙鲆中的组胺含量分别为422.57、640.00、309.63、151.86mg/kg,而虾、蟹、贝类等无脊椎动物几乎不产生组胺。不同水产品在腐败过程中产生的生物胺种类、含量、比例不同。生物胺总量可作为水产品腐败变质程度的指标。  相似文献