Molecular structural differences between maize leaf and endosperm starches

The morphology, whole molecular size distribution and chain-length distribution of maize leaf starch have been characterized and compared to its endosperm starch, to better understand differences between leaf and endosperm starch structure, and the relationship with the functions of starch in these organs. Leaf starch is found to have amylopectin with much shorter chains (virtually none with a degree of polymerization, DP, above 70) than the endosperm amylopectin, which has significant numbers of chains with DP up to ∼120, and has much smaller molecular size (and is present at a much lower amount) than endosperm starch. It is postulated that these pronounced differences arise from the distinct starch synthesis pathways in these organs, and are consistent with the starches’ distinct botanical functions: short-term storage requiring relatively rapid degradation for leaf starch, and high crystallinity and high energy density requiring slow degradation for endosperm starch

BID mediates selective killing of APC-deficient cells in intestinal tumor suppression by nonsteroidal antiinflammatory drugs

Colorectal tumorigenesis is driven by genetic alterations in the adenomatous polyposis coli (APC) tumor suppressor pathway and effectively inhibited by nonsteroidal antiinflammatory drugs (NSAIDs). However, how NSAIDs prevent colorectal tumorigenesis has remained obscure. We found that the extrinsic apoptotic pathway and the BH3 interacting-domain death agonist (BID) are activated in adenomas from NSAID-treated patients. Loss of BID abolishes NSAID-mediated tumor suppression, survival benefit, and apoptosis in tumor-initiating stem cells in APC(Min/+) mice. BID-mediated cross-talk between the extrinsic and intrinsic apoptotic pathways is responsible for selective killing of neoplastic cells by NSAIDs. We further demonstrate that NSAIDs induce death receptor signaling in both cancer and normal cells, but only activate BID in cells with APC deficiency and ensuing c-Myc activation. Our results suggest that NSAIDs suppress intestinal tumorigenesis through BID-mediated synthetic lethality triggered by death receptor signaling and gatekeeper mutations, and provide a rationale for developing more effective cancer prevention strategies and agents

Reservoir-forming characteristics of Baiyinchagan Sag in Erlian Basin

The oil and gas exploration in Baiyinchagan Sag, Erlian Basin, has been 30 years, with no breakthrough until 2003. In the area of being thought with no oil, some high-yielding prolific fields and high-quality scale reserves have been discovered, by reexamining the old data to establish a new reservoir formation pattern, and with new exploration concepts, from resource evaluation, major structural background optimization and big sand body searching and its combination with structural background, to applying 3D seismic technology and other technologies to identify the traps of small structures, faulted blocks and sand bodies. Many new fields have been discovered, such as Sanghe, West Sanghe, Daerqi, West Daerqi, West Wengte and Xilinhaolai, with proved oil in place up to several tens of million tons and an additional annual capacity of 10×104 t. The exploration history and experience in Baiyinchagan Sag will throw new light for risk exploration of other old sags. 摘要: 二连盆地白音查干凹陷油气勘探已有30年历史, 但直到2003年油气勘探才取得重大突破, 在一度被认为没有油气聚集的地方, 通过对老资料的重新认识, 构建新的成藏模式, 从资源评价、优选大型构造背景、寻找大砂体及其与构造背景的结合, 到应用三维地震等技术精细落实小构造、小断块、小砂体等圈闭, 创新勘探思路, 发现高产富集油气田和优质规模储量。截至目前, 油气勘探不断有新的发现, 已先后发现桑合、桑合西、达尔其、达尔其西、翁特西和锡林浩来6个油田, 探明石油储量数千万吨, 新建年产能力10×104 t。白音查干凹陷油气勘探的历史和经验, 对其他老凹陷的风险勘探将有所启示。 Key words: Baiyinchagan Sag, reservoir formation model, exploration breakthrough, exploration concept, exploration targe

Enhancing antimicrobial activity in unbleached kraft pulp using laccase and phenolic compounds

Unbleached kraft pulp fibers were reacted with laccase in the presence of different phenolic compounds (isoeugenol, butyl p-hydroxybenzoate, p-coumaric acid, and ferulic acid) in order to confer them with new properties. After the enzymatic stage, antimicrobial tests demonstrated that the handsheets formed from the laccase/phenolic-treated pulp showed a greater efficacy against Gram-positive and Gram-negative bacteria compared to handsheet paper treated only with laccase and a control. Laccase in the presence of butyl p-hydroxybenzoate produced handsheets with the most significantly enhanced bactericidal effect. An analysis of scanning electron microscope images of the treated kraft pulps increased kappa numbers and surface features of the fibers. The reduction in the absolute value of the zeta potential of the pulps indicates that the phenolic compounds produce chemical cross-linking within the fiber surface. X-ray photoelectron spectroscopy shows that the lignin content of the pulp fiber surface increased after adding the laccase and phenolic compounds