A 28-fold increase in secretory protein synthesis is associated with DNA puff activity in the salivary gland of Bradysia Hygida (Diptera, Sciaridae)

When the first group of DNA puffs is active in the salivary gland regions S1 and S3 of Bradysia hygida larvae, there is a large increase in the production and secretion of new salivary proteins demonstrable by [3H]-Leu incorporation. The present study shows that protein separation by SDS-PAGE and detection by fluorography demonstrated that polypeptides range in molecular mass from about 23 to 100 kDa. Furthermore, these proteins were synthesized mainly in the S1 and S3 salivary gland regions where the DNA puffs C7,C5,C4 and B10 are conspicuous, while in the S2 region protein synthesis was very low. Others have shown that the extent of amplification for DNA sequences that code for mRNA in the DNA puffs C4 and B10 was about 22 and 10 times, respectively. The present data for this group of DNA puffs are consistent with the proposition that gene amplification is necessary to provide some cells with additional gene copies for the production of massive amounts of proteins within a short period of time (Spradling AC and Mahowald AP (1980) Proccedings of the National Academy of Sciences, USA, 77: 1096-1100).

Synthesis and biological activities of some human gastrin analogs

The synthesis of analogs of the C-terminal tridecapeptide of gastrin in described. These pseudopeptide analogs were obtained either by replacing the C-terminal phenylalanine amide with 2-phenylethytalcohol or with 2-phenylethylamine, or by replacing the peptid bond between Trp and Leu, or between Leu and Asp with an aminomethylene (CH2NH). The ability of these compounds to stimulate gastric acid secretion in anesthetized rats and to inhibit binding of labeled CCK-8 to isolated cells from rabbit fundic mucosa was tested. [desPhe13, Leu11]-HG-12-I-beta-phenylethylester 33, [desPhe13, Leu11]-HG-12-II-beta-phenylethylester 38 [desPhe13, Leu11]-HG-12-I-beta-phenylethylamide 32, and [desPhe13, Leu11]-HG-12-II-beta-phenylethylamide 37 acted as gastrin receptor antagonists, while [Trp10-((CH2NH)-Leu11]-HG-13-I 31 and (Trp10-((CH2NH)-Leu11]-HG-13-II 36 acted as agonists. Unexpectedly, [Leu11-((CH2NH)-Asp12]-HG-13-I 30 and [Leu11-((CH2NH)-Asp12]-HG-13-II 35 were almost devoid of affinity for the gastrin receptor.

Prostaglandin A1, inhibits replication of Mayaro virus in Aedes albopictus cells

Prostaglandin A1 (PGA1) reduced Mayaro virus replication in Aedes albopictus (mosquito) cells in culture. The highest nontoxic dose of PGA1, 7.5µM, decreased virus production by 90 percent. In Mayaro virus-=infected cells, PGA1 inhibited virus-specific protein synthesis. However, in mock-infected cells the presence of PGA, stimulated the synthesis of several proteins with molecular masses of 70, 57 and 23 kDa, respectively. The data obtained from this study show that PGA1 plays a role in the metabolic regulation of Aedes albopictus cells, blocking the synthesis of Mayaro virus and inducing the synthesis of cellular polypeptides

Analise conformacional de modelos de peptidios para a proteina aderente do mexilhao, Mytilus edulis L / Conformational analyses of model peptides for the adhesive protein of the mussel, Mytilus edulis L

Efetuaram-se simulacoes de dinamica molecular a 298 K, usando o programa MOLSIM, para o tridecamero peptidico modelo da proteina aderente do mexilhao Mytilus edulis L. Os resultados estruturais sao comparados aos obtidos com o uso de tecnicas de mecanica molecular e de minimizacao de energia. O tridecamero adota estrutura de dupla volta reversa para as sequencias Lys-Pro-Ser-Tyr e Hyp-Hyp-Thr-Dopa. Na primeira volta, encontrou-se estrutura beta em mais que 50 porcento das simulacoes. Para as trajetorias remanescentes, adotou-se geralmente uma volta gama, composta de residuos de Lys-Pro-Ser. A segunda volta e uma volta beta, que e conservada atraves de simulacoes utilizando modelos e temperaturas diferentes. As duas voltas adjacentes garantem estrutura globular para o modelo da proteina, que e mantida em faixas de constantes dieletricas moleculares entre 1 e 15. Encontrou-se uma conformacao estendida como sendo uma conformacao secundaria, de energia maior em 40-90 kcal tridecamero. Identificaram-se diversas ligacoes de hidrogenio, que mantem a volta dupla estavel. A maioria dessas ligacoes de hidrogenio compreende um grupo OH, que pode explicar a porcentagem extraordinariamente alta de residuos contendo OH, especialmente Hyp e Dopa. A conformacao do modelo de proteina incorpora cadeias laterais de Lys, Dopa e Tyr, que apresentam as funcoes polares proximas umas das outras. Esse arranjo favorece uma geometria de ligacao cruzada na proteina, proposta a partir dos resultados experimentais com a placa aderente

Neutralización del virus de la fiebre aftosa O1 Campos por anticuerpos inducidos por un péptido sintético / Neutraliztion of fost-and-mouth diseases virus O1 Campos by antibodies induced by synthetic peptide

Un hexadecapéptido correspondiente a la secuencia 144-159 de la proteína estructural VP1 del virus de la fiebre aftosa (CFA), cepa O1K, fue sintetizado por métodos químicos. El mismo, acoplado covalentemente a distintas proteínas portadoras, demostró su capacidad de inducir anticuerpos neutralizantes del VFA cepa O1 Campos (O1Ca) en ratones adultos. La protección fue del 100% cuando se lo acopló a la hemocianina de un molusco (KLH) y fue inoculado en cantidad de 60 microng, dividida en dos dosis y adyuvada con mezcla oleosa. Las proteínas utilizadas como portadoras: albúmina bovina, purificado proteico de Mycobacterium (PPD), gliadina y células de Brocelas produjeron una respuesta inmune menor que la KLH

Excreción de calicreína urinaria en niños sanos a distintas edades / Urinary kallikrein excretion in healthy children at different ages

La calicreína es una proteína que genera, luego de varias transformaciones, bradicina, una sustancia con potente acción vasodilatadora. En 53 niños de ambos sexos, sanos y normotensos, cuyas edades fluctuaron entre 12 días y 15 años, se midió calicreína urinaria, expresándola en su valor absoluto y en relación a la masa renal. La calicreína urinaria es francamente inferior en el grupo de menores de 6 meses. (0.30 + ou - 0.29 uU 24 hrs.) con respecto a los valores obtenidos en los lactantes y niños mayores (9.46 + ou _ 2.7 y 16.1 + ou - 3,7 uU 24 hrs.). Concluimos que la excreción urinaria de calicreína es significativamente menor en los menores de 6 meses, lo que puede estar relacionada con la maduración renal