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In North Kazakhstan there is concern about the degradation of Chernozem soil and agricultural sustainability by the inclusion and frequency of summer fallows in crop rotations in terms of their influence on the changes of soil organic matter (SOM) quality and quantity. We examined five fallow-wheat (Triticum aestivum L.) cropping systems with different frequencies of the fallow phase in Chernozem soil of North Kazakhstan; continuous wheat (CW), 6-y rotation (6R), 4-y rotation (4R), 2-y rotation (2R) and continuous fallow (CF). Soil samples were collected from the two phases of each rotation, pre- and post-fallow, and analyzed for potentially mineralizable C (PMC) and N (PMN), ‘light fraction’ organic matter (LF-OM), C (LF-C) and N (LF-N). Potentially mineralizable C was inversely proportional to the frequency of fallow and was highest in CW. Mineral N (min-N) and PMN were more responsive to rotation phase than other indices of SOM. Mineral N was higher in the post-fallow phase while PMN was higher in the pre-fallow phase. Light fraction organic matter was negatively correlated to the frequency of fallow and was higher in the pre-fallow than in the post-fallow phase in a rotation. The results suggested that the yearly input of plant residue in a less frequently fallowed system built up more PMC, whereas PMN was closely correlated to recent inputs of substrate added with plant residues. We conclude that a frequent fallow system may deplete SOM via accelerated mineralization. Also that LF-OM, PMC and PMN are more sensitive to detect subtle changes in SOM quality than total SOM. Our results may provide prediction of SOM response to fallow frequency in wheat-based rotation systems in Chernozem soils of semi-arid regions.  相似文献   
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Although there are a number of Vietnamese native pig (VnP) populations, some are on the verge of extinction, and therefore adequate management and conservation are necessary. In this study, we conducted a field survey of VnP populations and analyzed interrelationships among their characteristics. We also established a relational database for management of field data on these populations. For data collection, we conducted interviews with farmers and visual inspection of 32 VnP populations in 22 provinces of Vietnam, as well as taking photographs of individual animals. Data on the characteristics of VnP populations were subjected to multiple correspondence analysis (MCA). For establishment of the database, normalization and table partitioning were performed to eliminate redundancy and ensure consistency of the collected data items. Passport data, characteristics data, and image data were collected from a total of 1,918 VnPs and entered as a normalized table. Upon MCA, most of the populations were not separated from each other, but the Mong Cai, O Lam, and Chu Prong populations were separated from the other populations. Thus, we have constructed a relational database from comprehensive information on the characteristics of VnP populations.  相似文献   
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The location of Pepper mild mottle virus (PMMoV) within seeds as they developed on inoculated seedlings of pepper (Capsicum annuum) was followed over time by detecting the viral coat protein using immunofluorescence microscopy. Seedlings were inoculated with PMMoV when the flower buds on the first and second branching nodes were in bloom. Fluorescence indicating the presence of PMMoV was first observed around immature seeds and placentas in the ovaries on the fourth branching node at 20 days post-anthesis (20 DPA), which corresponded to 39 days post-inoculation (39 DPI). The area with fluorescence gradually expanded from the placenta into the integument and the parenchyma, and finally reached the tip of the immature seeds by 34 DPA (53 DPI). The embryo or endosperm beyond the endothelium never fluoresced during the experiment [i.e., ending at 81 DPA (102 DPI)]. For visualizing viral routes of invasion from seeds into new seedlings, PMMoV-infected C. annuum seeds that were heterozygous for the L 3 tobamovirus-resistance gene were sown in soil at 30°C. After ~2 weeks, the cotyledon developed virally induced necrosis. These findings shed light on the infection cycle of PMMoV through vertical transmission in C. annuum.  相似文献   
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Changes in an individual's immune status are considered major contributing factors towards the morbidity of cancer and mortality of aging. To evaluate age-related changes in the immune status of dogs, the immunophenotypes (CD3, CD4, CD8 and CD21) of peripheral blood lymphocytes were measured in 160 healthy dogs aged from 1 to 17 years, and in 365 dogs with various tumors and at various stages. In healthy dogs, the absolute numbers of white blood cells, lymphocytes, and CD3(+), CD4(+) and CD21(+) lymphocytes decreased significantly with age. The relative percentages of lymphocytes and CD4(+) cells decreased significantly, while CD8(+) cells increased significantly with age. The CD4:CD8 ratio showed a significant age-related decrease. In contrast, dogs with tumors possessed significantly lower absolute numbers and relative percentages of all lymphocyte phenotypes, while the CD4:CD8 ratio was significantly higher than in age-matched controls. The relative percentages of CD3(+) and CD8(+) lymphocytes were significantly lower in dogs with distant metastases compared with dogs without metastases, and the CD4:CD8 ratio increased with advanced stage. These observations illustrate the significant changes in immune status with age and the presence of marked immunological defects in a large-scale study of dogs with advanced tumors.  相似文献   
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Cocoa powder is rich in polyphenols, such as catechins and procyanidins, and has been shown to inhibit low-density lipoprotein (LDL) oxidation and atherogenesis in a variety of models. Human studies have also shown daily intake of cocoa increases plasma high-density lipoprotein (HDL) and decreases LDL levels. However, the mechanisms responsible for these effects of cocoa on cholesterol metabolism have yet to be fully elucidated. The present study investigated the effects of cacao polyphenols on the production of apolipoproteins A1 and B in human hepatoma HepG2 and intestinal Caco2 cell lines. The cultured HepG2 cells or Caco2 cells were incubated for 24 h in the presence of cacao polyphenols such as (-)-epicatechin, (+)-catechin, procyanidin B2, procyanidin C1, and cinnamtannin A2. The concentration of apolipoproteins in the cell culture media was quantified using an enzyme-linked immunoassay, and the mRNA expression was quantified by RT-PCR. Cacao polyphenols increased apolipoprotein A1 protein levels and mRNA expression, even though apolipoprotein B protein and the mRNA expression were slightly decreased in both HepG2 cells and Caco2 cells. In addition, cacao polyphenols increased sterol regulatory element binding proteins (SREBPs) and activated LDL receptors in HepG2 cells. These results suggest that cacao polyphenols may increase the production of mature form SREBPs and LDL receptor activity, thereby increasing ApoA1 and decreasing ApoB levels. These results elucidate a novel mechanism by which HDL cholesterol levels become elevated with daily cocoa intake.  相似文献   
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Since BSE testing of slaughtered cattle is obligatory in Japan, storage of ovaries at 15-20 C overnight in phosphate buffered saline has become a routine protocol in in vitro production (IVP) of cattle embryos. Ovary storage is known to reduce developmental competence of oocytes; however, its effects on oocyte gene expression have not been clarified yet. This study compared oocytes collected from stored slaughterhouse-derived ovaries with those collected by Ovum Pick-Up (OPU) in terms of the expression of 20 selected genes to determine if ovary storage affects cellular processes at the molecular level. Expression of mRNA in oocytes was assayed before and after in vitro maturation (IVM) by real-time quantitative PCR. Maternal mRNA levels of genes were investigated in 2-cell stage embryos obtained from slaughterhouse oocytes to assess their roles for blastocyst formation. In immature OPU oocytes, genes related to metabolism (GAPDH), transporters (GLUT8, ATP1A1) and stress resistance protein (HSP70) showed significantly higher expression compared with oocytes derived from stored ovaries. During IVM, the expression of GDF9, GLUT8, CTNNB1 and PMSB1 was significantly decreased irrespective of oocyte source. Two-cell stage embryos cleaving at 22-25 h after in vitro fertilization (IVF) showed a significantly higher blastocyst formation rate and ATP1A1 gene expression level compared with those cleaving at 27-30 h after IVF. Our results reveal that storage of ovaries alters mRNA levels in oocytes. Correlation of Na/K ATPase ATP1A1 expression in IVP embryos at the 2-cell and 8-cell stages with their developmental ability to the blastocyst stage may suggest the importance of maternal mRNA of this gene during blastulation in embryos derived from slaughterhouse oocytes.  相似文献   
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