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821.
A series of rationally designed platanic acid-based compounds derived from naturally occurring betulinic acid were synthesized through a sequence of Lemieux-Johnson oxidation and Aldol condensation reaction. All the compounds were screened for cytotoxicity against a panel of human cancer and normal cell lines using MTT assay. From the biological data, it was observed that some of these semi-synthetic congeners exhibited potent biological profiles compared to platanic acid. One of the compounds with the p-tolyl substitution was found to be most active in this study, and its cytotoxicity against two of the cell lines, MDA-MB 231 and A-549 were in tune with the standard compound, 5-fluorouracil.  相似文献   
822.
Plant Cell, Tissue and Organ Culture (PCTOC) - Oryza alta Swallen is an important germplasm for rice resistance breeding; however, its CCDD genome (2n?=?48) resulted in low crossability...  相似文献   
823.
Phagocytosis plays a key role in nutrient uptake and virulence of the protist parasite Entamoeba histolytica. Phagosomes have been characterized by proteomics, and their maturation in the cells has been studied. However, there is so far not much understanding about initiation of phagocytosis and formation of phagosomes at the molecular level. Our group has been studying initiation of phagocytosis and formation of phagosomes in E. histolytica, and have described some of the molecules that play key roles in the process. Here we show the involvement of EhAK1, an alpha kinase and a SH3 domain containing protein in the pathway that leads to formation of phagosomes using red blood cell as ligand particle. A number of approaches, such as proteomics, biochemical, confocal imaging using specific antibodies or GFP tagged molecules, expression down regulation by antisense RNA, over expression of wild type and mutant proteins, were used to understand the role of EhAK1 in phagocytosis. EhAK1 was found in the phagocytic cups during the progression of cups, until closure of phagosomes, but not in the phagosomes themselves. It is recruited to the phagosomes through interaction with the calcium binding protein EhCaBP1. A reduction in phagocytosis was observed when EhAK1 was down regulated by antisense RNA, or by over expression of the kinase dead mutant. G-actin was identified as one of the major substrates of EhAK1. Phosphorylated actin preferentially accumulated at the phagocytic cups and over expression of a phosphorylation defective actin led to defects in phagocytosis. In conclusion, we describe an important component of the pathway that is initiated on attachment of red blood cells to E. histolytica cells. The main function of EhAK1 is to couple signalling events initiated after accumulation of EhC2PK to actin dynamics.  相似文献   
824.
Jojoba is a dioecious shrub with female and male flowers in separated individuals. The plant native to North and Central American deserts, it’s cultivated in many other places worldwide for its valuable liquid wax. The male-biased ratio in cultivated jojoba affects the yield. To develop protein molecular markers for early gender differentiation, comparative proteomic study been conducted on male and female leaves. Using gel-based proteomic, 45 proteins were identified representing 19 different proteins with 18 known functions. The identified proteins were involved in photosynthesis, energy, metabolism and the respond to biotic and abiotic stress. Ribulose-1,5-bisphosphate carboxylase (Rubisco) and ATP synthase were the most abundant proteins in both male and female of jojoba leaves, both were upregulated in male compared to female. Both proteins have the potential to serve as protein biomarkers for early differentiation between male and female in jojoba plant. These results could help in better understanding the molecular mechanism of gender differentiation in jojoba.  相似文献   
825.
A fatty acid, found as a minor component in the seed oil of Baliospermum axillare, is shown to be the hitherto unknown 11,13-dihydroxytetracos-trans-9-enoic acid (axillarenic acid).  相似文献   
826.
This study describes the isolation of temperate B. anthracis phages, from 4 out of 20 B. anthracis strains screened, by use of the inducing agents mitomycin C and UV light. Phage φ20 isolated from B. anthracis Sterne 34F2 (pXO1+ pXO2) was shown to have double-stranded DNA of size 48756 bp and a restriction site map showing nine sites for enzymes BamHI, BglII, and SstI is included. The φ20 genome was found to exist as a plasmidial prophage and the phage itself to have a polyhedral head of diameter 65 nm and tail 217 nm long and 15 nm wide.  相似文献   
827.
We describe endorhizal fungi associated with Equisetum species collected from Ellesmere Island (82°N), Axel Heiberg Island (80°N), and from sites in Yukon Territory and the Prairie Provinces (51–67°N). Fungal colonization was assessed using a multiple quantitation microintersect method for lactofuchsin-stained roots examined with wide-field and confocal epifluorescence microscopy. Equisetum roots host abundant and diverse endorhizal fungal associates. For 85 specimens from 14 sites, total colonization averaged 30 ± 3%, range 0–97%. Colonization rates for wide aseptate hyphae characteristic of arbuscular mycorrhizae (5 ± 1%) was significantly less than for fine endophytes (20 ± 3%) or septate endophytes (17 ± 2%). Equisetum spp. are abundant in tundra and an important understory plant in boreal forests, where they are particularly common on burned or disturbed sites. Endorhizal fungi associated with Equisetum may have broad ecological relevance.  相似文献   
828.
The proton-driven ATP synthase (FOF1) is comprised of two rotary, stepping motors (FO and F1) coupled by an elastic power transmission. The elastic compliance resides in the rotor module that includes the membrane-embedded FO c-ring. Proton transport by FO is firmly coupled to the rotation of the c-ring relative to other FO subunits (ab2). It drives ATP synthesis. We used a computational method to investigate the contribution of the c-ring to the total elastic compliance. We performed principal component analysis of conformational ensembles built using distance constraints from the bovine mitochondrial c-ring x-ray structure. Angular rotary twist, the dominant ring motion, was estimated to show that the c-ring accounted in part for the measured compliance. Ring rotation was entrained to rotation of the external helix within each hairpin-shaped c-subunit in the ring. Ensembles of monomer and dimers extracted from complete c-rings showed that the coupling between collective ring and the individual subunit motions was independent of the size of the c-ring, which varies between organisms. Molecular determinants were identified by covariance analysis of residue coevolution and structural-alphabet-based local dynamics correlations. The residue coevolution gave a readout of subunit architecture. The dynamic couplings revealed that the hinge for both ring and subunit helix rotations was constructed from the proton-binding site and the adjacent glycine motif (IB-GGGG) in the midmembrane plane. IB-GGGG motifs were linked by long-range couplings across the ring, while intrasubunit couplings connected the motif to the conserved cytoplasmic loop and adjacent segments. The correlation with principal collective motions shows that the couplings underlie both ring rotary and bending motions. Noncontact couplings between IB-GGGG motifs matched the coevolution signal as well as contact couplings. The residue coevolution reflects the physiological importance of the dynamics that may link proton transfer to ring compliance.  相似文献   
829.
Morchella spp. are wild edible mushrooms growing ephemerally under particular environmental conditions in temperate regions of the world. The present study was aimed to outline some principal eco-edaphic characteristics influencing distribution of these mushrooms from three different forest types of Swat, Pakistan. A randomized circular plots were laid down along the transect line in 14 stands in study areas. Environmental variables were recorded and soil characteristics were determined, analyzed and compared. Five species were collected from N to NW slope at elevation range of 1100-2695m asl. Mean relative humidity of 58.7%, range of air temperature 13 °C-27 °C and soil temperature 6-26 °C were recorded at morel growing sites. A higher canopy cover (average 57%) favours sporocarp formation in morels. Soil analysis showed that morel preferably appeared in sandy loam to loamy textured soil at slightly acidic to neutral pH (mean=6.4) and with consistently higher organic matter (1.5%) and salt activities (mean = 38.8 μS) in the soil. IVI calculation showed that Pinus wallichiana A. B. Jackson, Juglans regia L., Abies pindrow Royle, Cedrus deodara (Roxb. ex D. Don) G. Don were dominant trees and Viburnum grandiflorum Wall. ex DC, Hedra nepalensis K. Koch, Hert and Sarcococca saligna (D. Don) Muell. Arg. were shrub species associated with morels. Whilst Fragaria nubicola (Hook.f.) Lindl., Viola canescens Wall ex Roxb. and Podophyllum hexandrum Roylae were the predominant herbs in morel habitat. This study will help to understand the natural habitat and to provide a base line information for the future conservation and management planning in the area.  相似文献   
830.
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