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91.
Reclamation of Brazilian cerrados (savannas) has been intensified in the last decades, with implications for soil quality and soil organic matter (SOM) dynamics. Studying the impact of different tillage systems is essential to define better strategies for land use in Cerrado, which may favor C sequestration and improve soil quality. We used density fractionation and 13C natural abundance to assess changes in SOM in an Oxisol previously under a cerrado sensu-stricto following 30 years of cultivation. The objectives of the study were to: (i) evaluate the long-term impact of tillage systems on SOM stocks in a Dark Red Latosol (Oxisol) from the Cerrado Biome, and (ii) better understand the dynamics of SOM in different density fractions of this soil. Cultivation led to compaction, which significantly increased soil bulk density. This resulted in the systematic overestimation of C and N stocks in cultivated areas when compared to the natural cerrado. Conversion of the cerrado into cropland using plow tillage (PT) or no-tillage (NT) system did not alter the total C (100 Mg ha−1) and N (7 Mg ha−1) stocks in the first 45 cm depth at the end of 30 years of cultivation. However, about 22% of the total C was replaced by C from maize. The relative replacement of C decreased following the order: free light fraction (F-LF)>heavy fraction (HF)>occluded light fraction (O-LF). The low substitution in the O-LF was attributed to a possible presence of charcoal. Converting cerrado into cropland significantly decreased F-LF quantity. The proportions of C replacement in this fraction were higher in PT than NT, suggesting a faster turnover in PT. Nevertheless, because most C (95%) was held in the HF, C dynamics in the whole soil were controlled by the behavior of this fraction. The maintenance of C levels even at the end of 30 years of cultivation and the lack of differentiation between NT and PT were attributed to the high clay contents and Fe+Al oxi-hydroxides concentrations of the studied soil as well as to a sufficient C supply by the maize crop. 相似文献
92.
根据已发表的IL-12两个亚基P35 cDNA序列(NM-000882)与P40 cDNA序列(NM-002187)设计2对引物。以LPS刺激的人脐血淋巴细胞为材料,采用RT-PCR技术从总RNA扩增hIL-12基因,包括完整的前体蛋白编码序列。所得到的序列与GenBank中发表的一致,但与CLMF和NKSF序列有所差异。P35同CLMF相比,244aa密码子GAC(Asp)→GAT(Asp)、247aa密码子ACG(Thr)→ATG(Met);与NKSF比较,44aa密码子GTC(Val)→GTG(Val)。P40同NKSF比较239aa密码子AAC(Asn)→AAG(Lys),291aa密码子ACC(Thr)→ACG(Thr);P40同CLMF相比较,氨基酸与核苷酸序列完全一致。通过与不同物种氨基酸及核苷酸序列比较分析,P40亚基与其它动物的同源性80%以上,P35亚基与其它动物同源性在70%。 相似文献
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95.
本文讨论了土壤肥力管理信息系统的开发中能够提高开发效率和增加软件易用性的一些关键技术。另外,对数据库软件特有的其它一些技术问题如动态打开数据库和数据表、包含不定可选项字段的代码表的建立,以及同步计算等,作者也提出了自己的解决方法。 相似文献
96.
黄瓜新品种中农12号的选育 总被引:1,自引:1,他引:0
中农12号黄瓜的父母本98283和99281分别是从国内两个优良杂交种中经多代自交分离定向选择而成的优良黄瓜自交系。该品种为中早熟普通花型一代杂种,植株生长速度快,主蔓结瓜为主,瓜码较密。瓜条长棒形,瓜长30cm左右,瓜色深绿均匀,瘤小,白刺,单瓜质量150~200g,口感脆甜,品质佳。早熟,从播种到始收50d(天);丰产,每公顷产量75t以上。抗霜霉病、白粉病、CMV,中抗黑星病、角斑病、枯萎病。适宜北方早春保护地、早春露地和秋延后栽培。 相似文献
97.
SONG Yuhao LI Dong SUN Jiangyang SHI Kun LI Jianming ZONG Ying ZHAO Dan ZENG Fanli DU Rui 《畜牧兽医学报》1956,51(11):2613-2621
Clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR-related protein (Cas) system is a heritable prokaryotic adaptive immune system against invading nucleic acids. It is an editing tool for many organisms that can generate highly specific gene double-strand breaks and repair them by non-homologous end joining (NHEJ) or homologous recombination (HR). Due to the complexity of its genetic manipulation, Mycobacterium tuberculosis genome research has many difficulties. Therefore, the emergence of the CRISPR/Cas system has a milestone significance for the research of Mycobacterium tuberculosis. In this review, we focus on the application of the CRISPR/Cas system in Mycobacterium tuberculosis and summarizes the present research progress in order to provide a reference for the selection of Mycobacterium tuberculosis research methods. 相似文献
98.
An 11-year-old, male castrated, Labrador Retriever was evaluated for the presence of rapidly growing concurrent leg and intraocular masses. Metastasis was noted in the chest at time of initial presentation. Indium-111 labeled vitamin B12 imaging was performed, and there was significant uptake by both primary tumors and the lung metastases. Enucleation and amputation were performed for palliative relief. The leg mass was a grade 2 soft tissue sarcoma and the ocular mass a ciliary adenoma. The dog remained symptom-free for approximately 10 weeks before developing signs of respiratory distress. He was euthanized 12 weeks after initial presentation, and there was diffuse infiltration of the lungs with metastatic sarcoma. Indium-111 labeled vitamin B12 imaging identified a ciliary adenoma in this case and may provide a useful differentiation technique for evaluation of intraocular and retrobulbar masses if it can be demonstrated that there is differential uptake between inflammatory or infectious conditions and neoplasia. 相似文献
99.
Neutrophils (polymorphonuclear leukocytes: PMNs) are essential for the host defense against various infections and are often injurious to the host, causing inflammatory diseases where tumor necrosis factor-alpha (TNF-alpha) is suggested to play an important role. Since an effect of TNF-alpha on canine PMN apoptosis has not been studied, canine PMNs were stimulated with recombinant human (rh)TNF-alpha in the present study to investigate the effect of TNF-alpha on canine PMN apoptosis. PMN apoptosis and function to produce ROS were assessed by flow cytometry. Delayed apoptosis was observed in the PMNs treated with rhTNF-alpha at 100 ng/ml, accompanied by retention of capability to produce ROS. However, PMN apoptosis was accelerated by rhTNF-alpha combined with cycloheximide. Therefore, it is indicated that TNF-alpha is able to activate anti- and pro-apoptotic pathways in PMNs and that the inhibition of PMN apoptosis by TNF-alpha requires protein synthesis in the PMNs. 相似文献
100.
Manabu Nemoto Hiroshi Tsunemitsu Harutaka Murase Yasuo Nambo Shinsuke Sato Yasuhiro Orita Hiroshi Imagawa Hiroshi Bannai Koji Tsujimura Takashi Yamanaka Tomio Matsumura Takashi Kondo 《Acta veterinaria Scandinavica》2012,54(1):63