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971.
María V Croce Marina T Isla-Larrain Carina E Rua Martín E Rabassa Sandra J Gendler Amada Segal-Eiras 《The journal of histochemistry and cytochemistry》2003,51(6):781-788
Our aim was to determine the pattern of expression of MUC1 mucin cytoplasmic tail (MUC1 CT) in breast carcinoma. A total of 98 invasive breast adenocarcinoma tumor samples were assayed by immunohistochemical (IHC) analysis. The pattern of reaction was classified as membrane, cytoplasmic, or mixed. Subcellular fractions were prepared after SDS-PAGE and Western blotting. The antibodies employed were anti-MUC1 CT (CT2 monoclonal antibody, MAb) and C595 MAb against the extracellular MUC1 core protein. With the CT2 MAb, IHC showed a high percentage of positive staining in 93% of specimens, with membrane staining the most common pattern observed. C595 MAb was reactive in 73% of specimens. Similar percentages of membrane and cytoplasmic staining were found, mainly in a mixed pattern. Western blotting showed different bands. With the CT2 MAb, the membrane fraction showed the most intense reaction; a strong band of reaction was detected at approximately <30 kD. With the C595 MAb, in most cases a double band at 200 kD was found. In breast epithelium, the pattern of MUC1 CT expression may constitute an indicator of MUC1 production because it does not depend on glycosylation. The pattern and extension of MUC1 CT positivity do not vary according to the histopathological subtype of the tumor. 相似文献
972.
Melanocyte function and its control by melanocortin peptides. 总被引:32,自引:0,他引:32
Marina Tsatmali Janis Ancans Anthony J Thody 《The journal of histochemistry and cytochemistry》2002,50(2):125-133
Melanocytes are cells of neural crest origin. In the human epidermis, they form a close association with keratinocytes via their dendrites. Melanocytes are well known for their role in skin pigmentation, and their ability to produce and distribute melanin has been studied extensively. One of the factors that regulates melanocytes and skin pigmentation is the locally produced melanocortin peptide alpha-MSH. The effects of alpha-MSH on melanogenesis are mediated via the MC-1R and tyrosinase, the rate-limiting enzyme in the melanogenesis pathway. Binding of alpha-MSH to its receptor increases tyrosinase activity and eumelanin production, which accounts for the skin-darkening effect of alpha-MSH. Other alpha-MSH-related melanocortin peptides, such as ACTH1-17 and desacetylated alpha-MSH, are also agonists at the MC-1R and could regulate melanocyte function. Recent evidence shows that melanocytes have other functions in the skin in addition to their ability to produce melanin. They are able to secrete a wide range of signal molecules, including cytokines, POMC peptides, catecholamines, and NO in response to UV irradiation and other stimuli. Potential targets of these secretory products are keratinocytes, lymphocytes, fibroblasts, mast cells, and endothelial cells, all of which express receptors for these signal molecules. Melanocytes may therefore act as important local regulators of a range of skin cells. It has been shown that alpha-MSH regulates NO production from melanocytes, and it is possible that the melanocortins regulate the release of other signalling molecules from melanocytes. Therefore, the melanocortin signaling system is one of the important regulators of skin homeostasis. 相似文献
973.
974.
975.
Marina B. Chiappero Antonio Blanco Gladys E. Caldern Marta S. Sabattini Cristina N. Gardenal 《Biochemical Systematics and Ecology》2002,30(11):1023-1036
The genetic structure of populations of the Sigmodontinae rodent Calomys laucha was studied by means of allozyme electrophoresis. This highly opportunistic species is found preferably in periodically perturbed habitats of crop fields in central Argentina, where it can attain very high densities. A total of 17 enzymatic proteins assayed gave information on 25 loci; only four were monomorphic in the seven populations studied. Levels of genetic variability (Ho from 0.144 to 0.171; P95% from 44% to 56%) were higher than mean values reported for mammals and rodents. These high levels of heterozygosity could be maintained by large populations that do not experience great fluctuations in size, or by a social structure consistent in many small breeding groups that are formed and dissappear every breeding season. Genetic differentiation at a macrogeographical scale (θ=0.018) was low but statistically significant, and showed no correlation with geographic distance between pairs of populations. The pattern of population differentiation found is compatible with a relatively recent range expansion. 相似文献
976.
The evolutionary history of the bovid subfamily Antilopinae is unclear. Traditionally, this subfamily is subdivided into two tribes: Neotragini (dwarf antelopes) and Antilopini (gazelles and their relatives). Here, we report new sequences for the 12S and 16S rRNA genes in the enigmatic antilopine taxa Procapra gutturosa and Saiga tatarica and analyze the phylogenetic relationships of these taxa relative to other antilopines. Our study demonstrates the close affinity of the saiga antelope to Gazella despite the conventional systematic allocation of Saiga to the Caprinae subfamily. The second member of the Saigini tribe, Pantholops hodgsoni (Tibetan gazelle), falls within Caprinae. In all of our analyses, Procapra gutturosa occupied a basal position in the Antilopinae clade or was a sister-group to the dwarf antelope Madoqua. This suggests early separation of Procapra from other antelopes. 相似文献
977.
Laura Biondi Fernando Filira Marina Gobbo Raniero Rocchi 《Journal of peptide science》2002,8(2):80-92
Stepwise solution syntheses of the homo-oligomers Boc-(Asn)n-NHCH3 (n = 1-5; I1-5), Boc-[[GlcNAc(Ac)3beta]Asn]n-NHCH3 (n = 1-8; II1-8), and Boc-[(GlcNAcbeta)Asn]n-NHCH3 (n = 1-8; III1-8) are described. Members of the series III were obtained by deacetylation of the corresponding members of the series II. The conformational preferences of the N-protected homo-peptides of the three series were investigated by spectroscopic techniques. 1H-NMR measurements were carried out in various solvents; the CD spectra were recorded in water, aqueous SDS and TFE. The poor solubility of the oligomers of the three series prevented FT-IR measurements in solution. NMR and IR measurements indicate the existence of unordered structures containing some gamma-turns in the carbohydrate-free oligomers and the presence of beta-turns in the glycosylated oligopeptides, whether acetylated or not. The CD spectra do not indicate the presence of organized structures. The sugar moieties apparently do not have a structure-inducing effect on the asparagine homo-oligomer main chain. 相似文献
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979.
Carla Caruso Laura Bertini Marina Tucci Carlo Caporale Monica Nobile Luca Leonardi Vincenzo Buonocore 《Protein expression and purification》2001,23(3):380
PR proteins are soluble and host-coded molecules with antifungal activity induced by a variety of agents. Wheat contains several PR proteins and among them are those of the class 4 coded wheatwin1 and wheatwin2; the two native proteins have been isolated from wheat kernel and the coding cDNA clones have been recently characterized. Herein, we report the expression of recombinant wheatwin1 and wheatwin2 in Escherichia coli-insoluble fractions; a new protocol for the purification in high yields and correct processing of the two proteins was developed. The recombinant proteins have molecular weights identical to that of the native proteins, indicating that the removal of the N-terminal methionine and cyclization of glutamine to pyroglutamate was complete. Both recombinant proteins inhibited in vitro the growth of Fusarium culmorum exhibiting antifungal properties similar to those of the native proteins. 相似文献
980.