Effects of Addition of Tissue‐Type Plasminogen Activator in In Vitro Fertilization Medium on Bovine Embryo Development and Quality

Plasminogen activators/Plasmin system plays pivotal role in regulating reproductive functions of mammals. Here, we examined the effects of modification of in vitro fertilization medium (IVF medium) with the addition of tissue‐type plasminogen activator (t‐PA), on bovine embryo development and quality, assessed by quantification of expression of various genes related to metabolism, oxidation, implantation and apoptosis. In addition, plasminogen activator activity (PAA) and plasminogen activator inhibition (PAI) were measured in the spent media. After conventional IVM, 2016 cumulus‐oocyte complexes (COCs) were divided into four groups with modified composition of the IVF medium containing t‐PA and/or its inhibitor epsilon‐aminocaproic acid (control, t‐PA, t‐PA+ε‐ACA, ε‐ACA). Presumptive zygotes were cultured for 8 days in synthetic oviductal fluid (SOF) medium; gene expression studies were carried out on morulae and blastocysts. t‐PA alone significantly suppressed cleavage and blastocyst formation rates, but this effect was neutralized by the addition of ε‐ACA. PAA in the treated group was significantly reduced by ε‐ACA, but without total elimination. Significant differences were detected in the expression of genes related to apoptosis and/or cell cycle arrest (BAX, BCL2L1, KAT2B) between embryos produced in t‐PA‐modified media and controls, giving an overall notion that the inferior developmental competence of treated embryos may be attributed to apoptotic phenomena induced by t‐PA. In conclusion, it appears that excessive t‐PA content in the IVF media, suppresses blastocyst formation rate, possibly due to induction of apoptotic phenomena.     

Identification and characterization of a serine protease from wheat leaves

A putative serine protease with a potential role in the plant biotic and abiotic stress response was purified from wheat leaf apoplastic fluid and partially characterized. Following two-dimensional electrophoresis a protein of M_r = 75 k and a pI of 4.2 to 4.5 was observed. This protein displayed in-gel protease activity and was specifically inhibited by phenylmethanesulfonyl fluoride and partially inhibited by Ca²⁺ and Zn²⁺, but not by E-64 or leupeptin. An internal tryptic fragment of 13 amino acids was identified by MALDI QqTOF MS/MS, and this peptide showed a high level of homology (85–100 % identity) to a highly conserved region of known plant subtilisin-like proteases. We demonstrated that the protease activity increased until a late stage of wheat leaf development and increased in response to heat shock. In both cases Rubisco large subunit was degraded with time. Protease activity was also increased during biotic stress. Leaves challenged with leaf rust (Puccinia triticina), showed an approximately three fold increase in protease activity during an incompatible interaction, compared to activity in mock-inoculated leaves and to leaves in a compatible leaf rust interaction. These results suggest that the expression of this serine protease could be involved in the defense response against both abiotic and biotic stresses.     

Deleterious Effects of Progestagen Treatment in VEGF Expression in Corpora Lutea of Pregnant Ewes

The aim of the current study was to determine the possible effects of progestagen oestrous synchronization on vascular endothelial growth factor (VEGF) expression during sheep luteogenesis and the peri‐implantation period and the relationship with luteal function. At days 9, 11, 13, 15, 17 and 21 of pregnancy, the ovaries from 30 progestagen treated and 30 ewes cycling after cloprostenol injection were evaluated by ultrasonography and, thereafter, collected and processed for immunohistochemical evaluation of VEGF; blood samples were drawn for evaluating plasma progesterone. The progestagen‐treated group showed smaller corpora lutea than cloprostenol‐treated and lower progesterone secretion. The expression of VEGF in the luteal cells increased with time in the cloprostenol group, but not in the progestagen‐treated group, which even showed a decrease between days 11 and 13. In progestagen‐treated sheep, VEGF expression in granulosa‐derived parenchymal lobule capillaries was correlated with the size of the luteal tissue, larger corpora lutea had higher expression, and tended to have a higher progesterone secretion. In conclusion, the current study indicates the existence of deleterious effects from exogenous progestagen treatments on progesterone secretion from induced corpora lutea, which correlate with alterations in the expression of VEGF in the luteal tissue and, this, presumably in the processes of neoangiogenesis and luteogenesis.     

应用遥感、人工神经网络叶面积模型和模拟过程模型估计湿地松人工林碳储量

全球气候变化引起人们对森林碳固定作用的关注。碳存储速率依赖于生态系统流通量(光合作用和生态系统呼吸),量化为净生态系统二氧化碳交换。在没有密集采样点的情况下,我们需要采用估测森林净生态系统交换的方法准确地估计林分水平和更大尺度的碳固定量。本文通过祸合遥感估算的叶面积指数和生长过程拟合模型,估计了佛罗里达州内9 770公顷湿地松人工林一年里净生态系统交换总量。地面图神经网络模型和陆地卫星数据估计的森林叶面积指数平均值是1.06(数值范围0-3.93,包括森林边界)。输入神经网络叶面积指数值,湿地松拟合模型(SPM2)估计的森林净生态交换值在-5.52 Mg·hm-2·a-1到11.06Mg·hm-2·a-1之间,平均值是3.47 Mg·hm-2·a-1。年总的碳储量是33920t,约合3.5 t/hm2。估计的叶面积指数和森林净生态交换均对对施肥高度敏感。图3表1参30。     

Ontogenetic movements of juvenile blacktip reef sharks: evidence of dispersal and connectivity between coastal habitats and coral reefs

1. Connectivity between coastal habitats and mid‐shelf and offshore coral reefs is a topical issue in the conservation and management of fishes and coastal ecosystems.
2. Coastal habitats provide a range of ecosystem functions for sharks and rays and the use of coastal ecosystems by these species affects conservation and management outcomes. There is a growing need to better understand movement and habitat use patterns given recorded declines of many shark and ray species around the world.
3. This study presents evidence of connectivity of blacktip reef sharks between coastal and offshore habitats, with juveniles dispersing from natal grounds at the onset of maturity and moving to new locations including offshore coral reefs.
4. These dispersal patterns differ from previous accounts of reef shark movements and provide new evidence of connectivity among coastal habitats and offshore coral reefs.
5. These large‐scale movements may help to maintain genetic diversity of populations, and could increase the resilience of blacktip reef shark populations to localized pressures. These movement and connectivity patterns also illustrate the potential importance of coastal habitats to reef shark conservation.

Copyright © 2013 John Wiley & Sons, Ltd.