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In human‐modified landscapes, important ecological functions such as predation are negatively affected by anthropogenic activities, including the use of pesticides and habitat degradation. Predation of insect pests is an indicator of healthy ecosystem functioning, which provides important ecosystem services, especially for agricultural systems. In this study, we compare predation attempts from arthropods, mammals, and birds on artificial caterpillars in the understory, between three tropical agricultural land‐use types: oil palm plantations, rubber tree plantations, and fruit orchards. We collected a range of local and landscape‐scale data including undergrowth vegetation structure; elevation; proximity to forest; and canopy cover in order to understand how environmental variables can affect predation. In all three land‐use types, our results showed that arthropods and mammals were important predators of artificial caterpillars and there was little predation by birds. We did not find any effect of the environmental variables on predation. There was an interactive effect between land‐use type and predator type. Predation by mammals was considerably higher in fruit orchards and rubber tree than in oil palm plantations, likely due to their ability to support higher abundances of insectivorous mammals. In order to maintain or enhance natural pest control in these common tropical agricultural land‐use types, management practices that benefit insectivorous animals should be introduced, such as the reduction of pesticides, improvement of understory vegetation, and local and landscape heterogeneity.  相似文献   
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Background

Muscle satellite cells (MSCs) represent a devoted stem cell population that is responsible for postnatal muscle growth and skeletal muscle regeneration. An important characteristic of MSCs is that they encompass multi potential mesenchymal stem cell activity and are able to differentiate into myocytes and adipocytes. To achieve a global view of the genes differentially expressed in MSCs, myotube formed-cells (MFCs) and adipocyte-like cells (ALCs), we performed large-scale EST sequencing of normalized cDNA libraries developed from bovine MSCs.

Results

A total of 24,192 clones were assembled into 3,333 clusters, 5,517 singletons and 3,842contigs. Functional annotation of these unigenes revealed that a large portion of the differentially expressed genes are involved in cellular and signaling processes. Database for Annotation, Visualization and Integrated Discovery (DAVID) functional analysis of three subsets of highly expressed gene lists (MSC233, MFC258, and ALC248) highlighted some common and unique biological processes among MSC, MFC and ALC. Additionally, genes that may be specific to MSC, MFC and ALC are reported here, and the role of dimethylarginine dimethylaminohydrolase2 (DDAH2) during myogenesis and hemoglobin subunit alpha2 (HBA2) during transdifferentiation in C2C12 were assayed as a case study. DDAH2 was up-regulated during myognesis and knockdown of DDAH2 by siRNA significantly decreased myogenin (MYOG) expression corresponding with the slight change in cell morphology. In contrast, HBA2 was up-regulated during ALC formation and resulted in decreased intracellular lipid accumulation and CD36 mRNA expression upon knockdown assay.

Conclusion

In this study, a large number of EST sequences were generated from the MSC, MFC and ALC. Overall, the collection of ESTs generated in this study provides a starting point for the identification of novel genes involved in MFC and ALC formation, which in turn offers a fundamental resource to enable better understanding of the mechanism of muscle differentiation and transdifferentiation.  相似文献   
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This computational organic chemistry study illustrates that the size of the metal ion is a critical point in determining the bonding mode of the anthranilate (2-aminobenzoate). The beryllium model structure is the first example in the chemical literature on the ability of this amino acid to bond as N–O chelate. The medium has variable effect on the energies and the dipole moments of the studied models, which was found originating essentially from the differences in the atomic charges of the metals. Analysis of the molecular charge distribution allowed stating a new theory on the effect of the medium on the two pairs of isomers.  相似文献   
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Adham MN  Teimourian B 《Plastic and reconstructive surgery》1999,104(4):1118-25; discussion 1126-30
Patients with a bifid, cephalically rotated, contour-deformed, bulky, overprojected, pinched-tip, alar-dislocated, and/or alar-tethered nose had primary and secondary rhinoplasties using complete lateral alar cartilage mobilization, modification, and repositioning and the cartilage disc tip-graft technique. This technique avoids the pitfalls of classic in situ subtraction rhinoplasty and provides a better way to correct the nasal shape without causing airway obstruction. This technique was performed in 30 patients in the past 6 years who had primary or secondary rhinoplasties, with satisfactory results.  相似文献   
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The insulin-like factor 3 (Insl3), a member of the insulin-like hormone family, is exclusively synthesized in gonads. Our recent analysis of Insl3-deficient mice revealed the regulating role of the Insl3 factor on the gubernaculum development during the transabdominal descent of the testis. Here we define the role of the Insl3 factor by histometric analysis of wild-type and Insl3(-/-) ovaries. Ovaries from 40-day-old- and 6-month-old Insl3(-/-) mice as well as from wild-type littermates were serially sectioned. Sections were stained with periodic acid Schiff reaction (PAS) for counting the number of zonae pellucidae which indicated the final stages of follicular atresia. Corpora lutea were also determined. Some sections were processed using either a modified TUNEL method for in situ detection of apoptosis or a lectin labelling technique with Griffonia simplicifolia I agglutinin (GS I) for endothelial cell occurrence. The number of zonae pellucidae was higher in Insl3-deficient ovaries of both ages than in ovaries of wild-type sisters (P < 0.05 for 40-day-old ovaries; P < 0.01 for 6-month-old ovaries). Additionally, the wild-type mice of both ages possessed threefold more corpora lutea than their Insl3 littermates (P < 0.01 for 40-day-old; P < 0.001 for 6-month-old). In general, wild-type corpora lutea looked healthy, showed GS I-positive endothelial cells and no apoptotic cells. Corpora lutea from mutants were rich in regressing GS I luteal cells, and apoptotic cells appeared. We conclude: Follicular atresia and luteolysis are accelerated in ovaries of Insl3-deficient mice probably because of increased apoptosis. The Insl3 function thus appears to rescue endocrine cells from the apoptotic pathway.  相似文献   
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The sperm mitochondria-associated cysteine-rich protein (SMCP) is a cysteine- and proline-rich structural protein that is closely associated with the keratinous capsules of sperm mitochondria in the mitochondrial sheath surrounding the outer dense fibers and axoneme. To investigate the function of SMCP, we generated mice with a targeted disruption of the gene Smcp by homologous recombination. Homozygous mutant males on a mixed genetic background (C57BL/6J x 129/Sv) are fully fertile, while they are infertile on the 129/Sv background, although spermatogenesis and mating are normal. Homozygous Smcp(-/-) female mice are fertile on both genetic backgrounds. Electron microscopical examination demonstrated normal structures of sperm head, mitochondria, and tail. In vivo experiments with sperm of Smcp(-/-) 129/Sv mice revealed that the migration of spermatozoa from the uterus into the oviduct is reduced. This result is supported by the observation that sperm motility as determined by the computer-assisted semen analysis system (CASA) is significantly affected as compared to wild-type spermatozoa. In vitro fertilization assays showed that Smcp-deficient spermatozoa are able to bind to the oocyte but that the number of fertilized eggs is reduced by more than threefold relative to the wild-type control. However, removal of the zona pellucida resulted in an unaffected sperm-egg fusion which was monitored by the presence of pronuclei and generation of blastocyts. These results indicate that the infertility of the male Smcp(-/-) mice on the 129/Sv background is due to reduced motility of the spermatozoa and decreased capability of the spermatozoa to penetrate oocytes.  相似文献   
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