RESUMO
The morphological, physiological and genetic characteristics of an isolate cyanobacterium from hard sand of the lake Venere in the Pantelleria island (Italy) were described. The isolate with a small-size coiled helix shape, growing optimally at pH 9.2-9.5 at 30 degrees C under continuous illumination and aeration, possessed a 61.5 mol% of Guanine + Cytosine content of DNA. The lipid profile showed the presence of mono-, di-glycosyl, sulphoquinovolosyl and phosphatidyl (MGDG, DGDG, SQDG and PG). The fatty acid profile was also studied, characterized by the absence of gamma-linolenic acid and the presence of saturated and monounsaturated C16 and C18. The latter was also present as a dienoic component. The fatty acid composition was affected by growth temperature by increasing the degree of desaturation at a lower temperature and the biosynthesis of shorter acyl chains. The effects of growth conditions other than temperature, physical, nutritional and chemical on lipid composition were also studied. The overall features of the cyanobacterium isolated from Pantelleria clustered it into Spirulina genus.
Assuntos
Cianobactérias/classificação , DNA Bacteriano/química , Composição de Bases , Cianobactérias/genética , Cianobactérias/fisiologia , DNA Bacteriano/genética , Água Doce/microbiologia , Itália , Fosfolipídeos/química , Fosfolipídeos/isolamento & purificação , Microbiologia do SoloRESUMO
A repetitive HindIII fragment of DNA from Raja montagui (Rajiformes) was cloned and sequenced for the first time in cartilaginous fishes. This element, which comprises approximately 5% of the whole genome of the spotted ray, is absent in long tandem arrays, being typical of satellite DNA. It appeared constituted by 311 AT-rich bp (61%). The clone was hybridized to the genomic DNA of species with varying phyletic distances, revealing a high degree of conservation.
Assuntos
DNA Satélite , Desoxirribonuclease HindIII/metabolismo , Sequências Repetitivas de Ácido Nucleico , Rajidae/genética , Animais , Sequência de Bases , Clonagem Molecular , DNA Satélite/isolamento & purificação , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Peptides corresponding to retinoblastoma protein (RB) fragment 649-654 (LFYKKV) were tested for their ability to recognize the LXCXE sequence motif in human papilloma virus type 16E7 protein (HPV-16E7) encompassing E7 residues 21-26 (DLYCYE) and an identical motif in human insulin comprising insulin B-chain residues 16-21 (YLVCGE), respectively. Interaction between these complementary peptide sequences was observed by several approaches, including direct and competitive ELISA as well as affinity chromatography. Moreover, we demonstrated that immobilized RB649-654 displays specific recognition properties towards full-length insulin. Hence, this study provides a first experimental support for the previously anticipated complex formation between insulin and RB.
Assuntos
Insulina/química , Fragmentos de Peptídeos/química , Proteína do Retinoblastoma/metabolismo , Sequência de Aminoácidos , Cromatografia de Afinidade , Ensaio de Imunoadsorção Enzimática , Humanos , Insulina/metabolismo , Cinética , Dados de Sequência Molecular , Proteínas Oncogênicas Virais/química , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae , Proteínas E7 de Papillomavirus , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/metabolismo , Proteína do Retinoblastoma/química , Relação Estrutura-AtividadeRESUMO
Selachian chromosomes were investigated for the first time by C-, Ag- and RE (restriction endonuclease)-banding. A pair of NOR-bearing acrocentric chromosomes, as well as a third extra site, were demonstrated in two species of Torpedo. In situ digestion with restriction endonucleases revealed a peculiar arrangement of constitutive heterochromatin: in Torpedo ocellata the centromere never appeared C-banded, and was always digested by AluI, PstI, DdeI and HaeIII; in Torpedo marmorata, instead, heterochromatin was present in the centromere, and was not digested by the same enzymes. The occurrence of different types of centromeric heterochromatin suggests an involvement of highly repeated DNA fractions in the Robertsonian phenomena that occurred in chromosome rearrangements in the genus Torpedo.
