江西阳际峰自然保护区土壤的微生物学性状     

郑诗樟  王景明  肖青亮  乐新贵  张仪平 《江西农业大学学报》2012,(1):191-196

研究阳际峰自然保护区不同海拔梯度土壤剖面状况及其微生物学性状,探讨土壤微生物量C与N、酶活性、微生物商与呼吸速率的变化及其相互关系。结果发现,不同海拔梯度土壤在微生物学性状上均有较大差异。总的趋势是植被覆盖度高,地形平缓,土层厚,微生物活性强,且与海拔梯度呈显著正相关。在剖面分布上,也有明显的层次差异,即随土层的增加而减少。  相似文献   

Depletion study and estimation of the withdrawal period for oxytetracycline in tilapia cultured in Brazil     

Paschoal JA  Bicudo ÁJ  Cyrino JE  Reyes FG  Rath S 《Journal of veterinary pharmacology and therapeutics》2012,35(1):90-96

Defining pharmacokinetic parameters and depletion intervals for antimicrobials used in fish represents important guidelines for future regulation by Brazilian agencies of the use of these substances in fish farming. This article presents a depletion study for oxytetracycline (OTC) in tilapias (Orechromis niloticus) farmed under tropical conditions during the winter season. High performance liquid chromatography, with fluorescence detection for the quantitation of OTC in tilapia fillets and medicated feed, was developed and validated. The depletion study with fish was carried out under monitored environmental conditions. OTC was administered in the feed for five consecutive days at daily dosages of 80 mg/kg body weight. Groups of ten fish were slaughtered at 1, 2, 3, 4, 5, 8, 10, 15, 20, and 25 days after medication. After the 8th day posttreatment, OTC concentrations in the tilapia fillets were below the limit of quantitation (13 ng/g) of the method. Linear regression of the mathematical model of data analysis presented a coefficient of 0.9962. The elimination half-life for OTC in tilapia fillet and the withdrawal period were 1.65 and 6 days, respectively, considering a percentile of 99% with 95% of confidence and a maximum residue limit of 100 ng/g. Even though the study was carried out in the winter under practical conditions where water temperature varied, the results obtained are similar to others from studies conducted under controlled temperature.  相似文献   

Synovial tumours in dogs     

LE Craig 《New Zealand veterinary journal》2013,61(3)

The morphological characteristics, breed predispositions, site predilections and behaviour of three of the most common types of synovial tumours were discussed. Synovial histiocytic sarcoma represents 50% of synovial tumours, occurring in breeds predisposed to histiocytic sarcoma, and has a poor prognosis. Their histological appearance is similar to histiocytic sarcomas occurring elsewhere. The stifle is the most common site; dogs with ruptured cranial cruciate ligament are predisposed. Synovial cell sarcoma represents 15% of synovial tumours in dogs. They have non-specific spindle cell morphology, and can only be distinguished using cytokeratin immunohistochemistry, which will label a small percentage of the spindle cells. Amputation is often curative, but metastases can occur. Synovial myxoma represents 20% of synovial tumours in dogs. They have a characteristic morphology of myxomatous nodules filling the joint cavity and sometimes extending into the surrounding tissues, including bone. Labrador Retrievers and Doberman Pinschers are predisposed, and the stifle and digit are the most common sites. Prognosis is good; even with incomplete excision some dogs survive years without progression or metastasis. Histopathological examination of synovial tumours is essential to determine the course of treatment, and prognosis.  相似文献   

滑皮金柑和融安金柑外观、风味及营养成分比较     

马张正  马巧利  辜青青  勒思  雷常玉  魏清江 《浙江农业学报》2019,31(4):654

滑皮金柑是融安金柑的实生变异品种,为探明其品质特性,本研究以融安金柑为对照,比较二者果实外观、风味和营养成分的差异。结果表明,滑皮金柑单果质量、纵横径、果皮油胞数和色泽CCI值均显著低于融安金柑。滑皮金柑果实剪切力较低,其他质构指标均显著高于对照。糖酸含量分析表明:滑皮金柑果皮和果肉中葡萄糖、果糖、蔗糖以及总糖含量均显著高于融安金柑;滑皮金柑果皮中柠檬酸和苹果酸含量显著低于对照,而乙酸、马来酸和富马酸含量则显著高于对照;在果肉中,滑皮金柑的柠檬酸和丁二酸含量显著低于对照,而酒石酸、草酸、乙酸、马来酸、富马酸含量均显著高于对照。此外,滑皮金柑果皮和果肉中V_C含量相对较低,但总多酚和总黄酮含量显著高于对照。同时滑皮金柑中积累了更多香豆酸和阿魏酸,总酚酸含量也高于对照。  相似文献   

分散固相萃取结合气相串联质谱法检测 黑胡椒中19种农药残留          下载免费PDF全文

吴南村  张群  李春丽  刘春华  乐渊  吴学进 《南方农业学报》2019,50(3):656-661

[目的]建立分散固相萃取结合气相串联质谱法测定黑胡椒中敌敌畏、联苯菊酯、氯氰菊酯等19种农药残留的方法,为黑胡椒产品的多种农药残留同时检测提供技术支持.[方法]黑胡椒样品采用乙腈提取,提取液经吸附剂净化后过膜上机,由HP-5MS色谱柱分离,在电喷雾离子源的多反应监测模式下对19种农药进行检测.通过正交试验优化无水硫酸镁、乙二胺-N-丙基硅烷(PSA)、石墨化炭黑(GCB)和C184种吸附剂的配比.[结果]100 mg无水硫酸镁+20 mg PSA+50 mg GCB+40 mg C18为最佳配比的混合吸附剂;19种农药采用外标法定量;基质标准溶液在0.004~1.00 mg/L范围内线性关系良好(R>0.9900);53%农药为强基质效应,其中大部分为有机磷类农药,42%为中等基质效应;样品在3个不同添加水平下回收率为76.0%~114.0%,相对标准偏差(RSD)(n=3)在2.0%~12.0%,均小于15.0%,苯醚甲环唑检出限为0.010 mg/kg,其余农药检出限为0.007 mg/kg.[结论]建立的分散固相萃取结合气相串联质谱法前处理简单快速,准确度和精密度符合检测要求,适用于黑胡椒中敌敌畏等19种农药残留的同时检测.  相似文献   

QuEChERS-超高效液相色谱-串联质谱技术同时测定大蒜中10种农药残留     

林静  张顺  蔡挺  曹慧  刘鹏  荀凯  乐元洁 《浙江农业学报》2018,30(1):159

建立了快速、准确测定大蒜中10种农药多残留的QuEChERS-超高效液相色谱-串联质谱检测技术。样品经酸化乙腈提取,无水硫酸镁(500 mg)除水后,用N-丙基乙二胺(PSA,500 mg)和十八烷基键合硅胶(C₁₈,500 mg)净化,以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱,Waters C₁₈色谱柱分离,采用正离子多反应监测(MRM)模式检测,基质匹配标准溶液外标法定量。10种农药的检出限在0.020~0.800 μg·kg^-1,定量限在0.067~2.670 μg·kg^-1。线性范围内相关系数均大于0.99。加标回收率在73.4%~109.0%,相对标准偏差在1.2%~9.8%。结果表明,该方法简便、快速、灵敏度高、重现性好,可同时测定大蒜中10种农药。  相似文献   

Origin of adenohypophysial lobes and cells from Rathke's pouch in Swiss albino mice. Proliferation and expression of Pitx 2 and Calbindin D28K in corticotropic and somatotropic cell differentiation     

Reyes R  Martínez S  González M  Tramu G  Bello AR 《Anatomia, histologia, embryologia》2008,37(4):263-271

  相似文献   

Early Pregnancy Diagnosis by Serum Progesterone and Ultrasound in Sheep Carrying Somatic Cell Nuclear Transfer-Derived Pregnancies     

B Alexander  G Coppola  GF Mastromonaco  E St. John  ER Reyes  DH Betts  WA King 《Reproduction in domestic animals》2008,43(2):207-211

Early pregnancy diagnosis and monitoring play an important role following embryo transfer in sheep. The aims of the current study were to investigate (i) the pattern of serum progesterone profiles in sheep carrying somatic cell nuclear transfer (SCNT)‐derived (clone) pregnancies, and (ii) the frequency of pregnancy loss during development following SCNT embryo transfer. Sheep SCNT embryos were made using standard nuclear transfer techniques. Day 7 embryos were surgically transferred to oestrus‐synchronized recipients (n = 27). As a control, normal fertile ewes (n = 12) were bred by natural breeding. Serum was collected from all the ewes on the day of estrus (day 0 sample), 7 days post‐estrus (day 7 sample) and 19 days post‐estrus (day 19 sample) and every 10 days thereafter until lambing or pregnancy loss occurred. Serum progesterone (P4) was assessed using enzyme immunoassay. Pregnancy was confirmed by ultrasound scanning on day 35 of pregnancy followed by subsequent scanning every 10 days. In control ewes, pregnancy rate on day 35 was 83.3% (10/12), whereas in the ewes that received SCNT embryos, it was 22.2% (6/27; p < 0.05). The day 45 pregnancy rate in the control ewes was 83.3%, whereas in the SCNT embryo recipients it was 11.0% (p < 0.05). Hormone analysis revealed that SCNT embryo recipients exhibited a significantly lower P4 profiles at different time points in pregnancy compared to controls (p < 0.05). This study highlights the use of serum progesterone in combination with ultrasound for the investigation of embryo loss and crucial times during development of normal and SCNT embryos in sheep. Further, the serum P4 levels directly reflect the degree of placental development in these two groups.  相似文献   

DNA甲基化与去甲基化调控脂肪沉积的研究进展   总被引：2，自引：2，他引：0  

王鹤洁  秦本源  王媛媛  郭玉龙  宋鹏康  刘亚丹  乐宝玉  张宁芳  成志敏  高鹏飞  郭晓红  李步高  曹果清 《中国畜牧兽医》2019,46(2):519-525

脂肪沉积是一个复杂的生物学过程,受遗传和表观遗传的调控作用。DNA甲基化和去甲基化是表观遗传修饰的重要方式,可通过与转录因子的相互作用或改变染色质的结构调控基因的表达,进而参与机体生长发育和细胞分化等重要的生命过程。动物脂肪沉积是脂肪细胞增殖分化和肥大的结果,脂肪细胞分化是由多能干细胞经前体脂肪细胞向成熟脂肪细胞转化的过程。相关研究表明,转录因子过氧化物酶体增殖物激活受体γ(peroxi-some proliferator activiated receptorγ,PPARγ)和CCAAT增强子结合蛋白家族(CCAAT enchancer binding proteinfamily,CEBPs)在脂肪沉积过程中起关键调控作用。近期研究发现,DNA甲基化可以通过调控脂肪形成过程中相关基因的表达而参与脂肪细胞的分化和脂肪组织的生长发育。去甲基化也可影响动物脂肪沉积过程,但其具体机制目前尚不清楚。作者主要介绍了DNA甲基化和去甲基化的定义、发生位点、生物学功能、参与DNA甲基化和去甲基化过程中的酶及其作用机制,概述了脂肪沉积过程及PPARγ、C/EBPα等转录因子在脂肪沉积过程中的调控作用,重点阐述了DNA甲基化和去甲基化对脂肪形成相关基因的表达和对脂肪细胞分化的影响,旨在为阐明脂肪沉积机制及改善动物肉质品质提供参考。  相似文献   

Physiological considerations for efficient mycelial colonization of Philippine strains ofVolvariella volvacea     

Renato G. Reyes  Fumio Eguchi  Tomoaki Iijima  Miyato Higaki 《Journal of Wood Science》1998,44(5):408-413

The nutritional and physical requirements for the efficient mycelial colonization ofVolvariella volvacea (Bull. ex. Fr.). Singer were elucidated with the percentage mycelial colonization and density as references. This investigation was limited to the evaluation of two commercial strains (designated Vvc1 and Vvc2) and two wild strains (designated EAAC-0001 and EAAC-0002) ofV. volvacea from the Philippines with the aim of providing baseline data on their physiological requirements. The four strains ofV. volvacea had varying preferences for carbon. Vve1 preferred polysaccharides (starch and cellulose), whereas Vvc2 grew luxuriantly at a relatively rapid rate in sugar alcohol (sorbitol). The two wild strains preferred starch as a carbon source. In terms of nitrogen utilization, soytone, peptone, and glycine supported efficient mycelial colonization of the four strains. The vitamin utilization test revealed that ascorbic acid, calcium pantothenate, and biotin are good sources. The mycelial growth performances of the strains were also evaluated on six dehydrated mycological media. Efficient colonization of Vvc1, Vvc2, and EAAC-0002 with dense mycelial growth was noted in mycological agar. EAAC-0001, on the other hand, grew more efficiently in malt extract agar. The Philippine strains ofV. volvacea grew luxuriantly when incubated at 35°C and pH 8.0 under dark and sealed conditions. Moreover, the relatively higher moisture content (70%) of the oolong tea leaf formulation favorably stimulated efficient mycelial colonization. Under optimum physiological conditions, Vvc1, Vvc2, and EAAC-0002 were fast-growing strains, whereas EAAC-0001 was a moderately growing type.  相似文献