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21.
We employed a genetic approach to study protein glycosylation in the
procyclic form of the parasite Trypanosoma brucei. Two different mutant
parasites, ConA 1-1 and ConA 4-1, were isolated from mutagenized cultures
by selecting cells which resisted killing or agglutination by concanavalin
A. Both mutant cells show reduced concanavalin A binding. However, the
mutants have different phenotypes, as indicated by the fact that ConA 1-1
binds to wheat germ agglutinin but ConA 4-1 and wild type do not. A blot
probed with concanavalin A revealed that many proteins in both mutants lost
the ability to bind this lectin, and the blots resembled one of wild type
membrane proteins treated with PNGase F. This finding suggested that the
mutants had altered asparagine- linked glycosylation. This conclusion was
confirmed by studies on a flagellar protein (Fla1) and procyclic acidic
repetitive protein (PARP). Structural analysis indicated that the N- glycan
of wild type PARP is exclusively Man5GlcNAc2 whereas that in both mutants
is predominantly a hybrid type with a terminal N- acetyllactosamine. The
occupancy of the PARP glycosylation site in ConA 4-1 was much lower than
that in ConA 1-1. These mutants will be useful for studying trypanosome
glycosylation mechanisms and function.
相似文献
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Increased survival of preimplantation mouse embryos in medium with recombinant cytokine LIF 总被引:1,自引:0,他引:1
L. M. Mezhevikina V. V. Fedorova I. V. Kapralova E. E. Fesenko 《Russian Journal of Developmental Biology》2006,37(1):47-53
We studied the effects of cytokine LIF on in vitro development of 2-cell mouse embryos to the late blastocyst stage. LIF at 10 ng/ml enhanced the blastocyst formation and hatching from zona pellucida. When blastocysts were cultivated in a medium with LIF for a longer time, the trophoblast adhesive properties and proliferative activity were enhanced. In the presence of this cytokine, the trophoblast cells were attached to the substrate surface and fulfill the function of a sublayer for growth of the inner cell mass colonies with a high activity of endogenous alkaline phosphatase. Expression of LIF was detected in the oviduct and uterus epithelial tissues from day 1 until day 4 of pregnancy, thus suggesting its involvement in early development. According to the data of cultivation, cytokine LIF enhanced the adhesive properties and functional activity of the trophoblast cells, which is essential for implantation of blastocysts in the uterus. 相似文献
24.
KH Richau RL Kudahettige P Pujic NP Kudahettige A Sellstedt 《Journal of biosciences》2013,38(4):703-712
The actinorhizal bacterium Frankia expresses nitrogenase and can therefore convert molecular nitrogen into ammonia and the by-product hydrogen. However, nitrogenase is inhibited by oxygen. Consequently, Frankia and its actinorhizal hosts have developed various mechanisms for excluding oxygen from their nitrogen-containing compartments. These include the expression of oxygen-scavenging uptake hydrogenases, the formation of hopanoid-rich vesicles, enclosed by multi-layered hopanoid structures, the lignification of hyphal cell walls, and the production of haemoglobins in the symbiotic nodule. In this work, we analysed the expression and structure of the so-called uptake hydrogenase (Hup), which catalyses the in vivo dissociation of hydrogen to recycle the energy locked up in this ‘waste’ product. Two uptake hydrogenase syntons have been identified in Frankia: synton 1 is expressed under free-living conditions while synton 2 is expressed during symbiosis. We used qPCR to determine synton 1 hup gene expression in two Frankia strains under aerobic and anaerobic conditions. We also predicted the 3D structures of the Hup protein subunits based on multiple sequence alignments and remote homology modelling. Finally, we performed BLAST searches of genome and protein databases to identify genes that may contribute to the protection of nitrogenase against oxygen in the two Frankia strains. Our results show that in Frankia strain ACN14a, the expression patterns of the large (HupL1) and small (HupS1) uptake hydrogenase subunits depend on the abundance of oxygen in the external environment. Structural models of the membrane-bound hydrogenase subunits of ACN14a showed that both subunits resemble the structures of known [NiFe] hydrogenases (Volbeda et al. 1995), but contain fewer cysteine residues than the uptake hydrogenase of the Frankia DC12 and Eu1c strains. Moreover, we show that all of the investigated Frankia strains have two squalene hopane cyclase genes (shc1 and shc2). The only exceptions were CcI3 and the symbiont of Datisca glomerata, which possess shc1 but not shc2. Four truncated haemoglobin genes were identified in Frankia ACN14a and Eu1f, three in CcI3, two in EANpec1 and one in the Datisca glomerata symbiont (Dg). 相似文献
25.
S. G. Abbasova N. V. Rudenko A. Yu. Gorokhovatskii M. V. Kapralova I. D. Vinogradova Yu. V. Vertiev V. A. Nesmeyanov E. V. Grishin 《Russian Journal of Bioorganic Chemistry》2011,37(3):307-315
Mouse monoclonal antibodies to health-threatening botulinum neurotoxins (BoNTs) of types A, B, E, and F have been produced
and characterized. The antibodies are capable of interacting with a toxin inside the respective natural toxic complex. A sandwich
ELISA for the quantitative detection of botulotoxins has been developed on based on the antibodies. The detection limits of
the test systems for BoNTs A, B, E, and F is 0.4, 0.5, 0.1, and 2.4 ng/ml, respectively. The assay quantitatively detects
BoNTs in canned meat and vegetables. Two antibodies, BNTA-4.1 and BNTA-9.1, both separately and in combination, are capable
of neutralizing the natural botulinum toxic complex of type A in vivo; a combination of antibodies neutralizes a higher dose
of the toxin. It has been shown that the antibody BNTA-4.1 binds specifically to the light (catalytic) chain of the toxin,
and the antibody BNTA-9.1 interacts with the heavy chain. We believe that monoclonal antibodies BNTA-4.1 and BNTA-9.1 hold
promise for developing therapeutic antibodies to treat BoNT/A-caused botulism in an emergency. 相似文献
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Shah A S Rahim KH Bhatti A Khan N Din M Imran M Mohsin M Ishtiaq A Nabila A Ansari S Hussain M Zafar M Mushtaq E Mumtaz J Iqbal 《Phyton》2015,84(1):34-44
Sargodha district is one of the least studied regions of Pakistan regarding its ethnobotanical values. This paper is the first report related to the documentation and conservation status of the tree species in the Sargodha district, and their folk ethnobotanical uses. An interview base survey was conducted in the study area in 2010-2013. The ethnobotanical data revealed the use of 100 tree species (6 gymnosperms, 94 angiosperms) belonging to 77 genera (6 gymnosperms, 71 angiosperms) and 39 families (4 gymnosperms, 35 angiosperms), with the Fabaceae ranking first with 19 tree species, followed by the Moraceae (12 species). Tree species like Aegle marmelos, Butea monosperma, Diospyrus malabarica, Gmelina arborea, Kigelia africana, Manilkara hexandra, Manilkara zapota, Mimusops elengi, Nyctanthes arbor-tristis, Putranjiva roxburghii, Terminalia arjuna and Terminalia bellerica are not only unique in their medicinal value but also interesting because of their unusual occurrence here. Thevetia peruviana, Cassia fistula, Celtis australis, Delonix regia, Diospyrus malabarica, Grevillea robusta, Haplophragma adenophylum, Jacaranda mimosifolia, Lagerstroemia speciosa, Plumeria rubra, Pterospermum acerifolium, Roystonea regia, Taxodium distichum and Tectona grandis are included among the worth looking ornamental tree species. Capparis decidua, Dalbergia sissoo, Tamarix aphylla, Tamarix dioica, Prosopis cineraria and Ziziphus mauritiana are the most commonly used timber species. Other common ethnobotanical utilization of these trees includes either sheltering or fuel or agricultural uses. Lack of awareness about the potential uses of these species, and particularly ignorance of the concerned authorities, have led to a decline in the population of this precious tree flora. Documentation of this tree flora, and as-sociated indigenous knowledge, can be used as a basis for developing management plans for conservation and sustainable use of this flora in the study area. A well-organized management is critical to restore and conserve this endangered natural resource in the District Sargodha, Pakistan. The immense medicinal and timber value of these tree species make it necessary to promote their conservation to simultaneously alleviate the poverty and improve the socio-economic status of the study area. 相似文献
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We studied the effects of cytokine LIF on in vitro development of 2-cell mouse embryos to the late blastocyst stage. LIF at 10 ng/ml enhanced the blastocyst formation and hatching from zona pellucida. When blastocysts were cultivated in a medium with LIF for a longer time, the trophoblast adhesive properties and proliferative activity were enhanced. In the presence of this cytokine, the trophoblast cells were attached to the substrate surface and fulfill the function of a sublayer for growth of the inner cell mass colonies with a high activity of endogenous alkaline phosphatase. Expression of LIF was detected in the oviduct and uterus epithelial tissues from day 1 until day 4 of pregnancy, thus suggesting its involvement in early development. According to the data of cultivation, cytokine LIF enhanced the adhesive properties and functional activity of the trophoblast cells, which is essential for implantation of blastocysts in the uterus. 相似文献
30.