RESUMO
AIM: The aim of this study was to evaluate spinal cord injury and mortality resulting from repair of extent I and II thoracoabdominal aneurysm. The authors compared patients operated under mild hypothermia with or without epidural perfusion cooling (EPC) and cerebrospinal fluid drainage (CSFD). METHODS: From 1988 to 2007, 116 patients underwent replacement of the thoracoabdominal aorta; the procedure was performed in 38 patients with the aid of mild hypothermia alone (group A), and in 78 patients with the aid of EPC, mild hypothermia and CSFD (group B). Two catheters for epidural perfusion cooling were inserted in group B, in which one catheter was inserted into the epidural space to infuse chilled saline, and the other was inserted into the subdural space to drain the cerebrospinal fluid and to measure temperature and pressure. There were no significant differences in mean age, etiology of aortic disease, and aneurysm extent between the two groups. RESULTS: There were no significant differences in cardiopulmonary bypass time, the lowest nasopharyngeal temperature and operation time between the two study groups. The incidence of spinal cord injury in group A (16.2%) was significantly higher than in group B (3.8%, P=0.03). Hospital mortality in groups A and B was 10.5% and 2.6%, respectively (P=0.08). There was no significant difference in postoperative complications between the two study groups. CONCLUSION: The combination of EPC and CSFD was effective in lowering the incidence of postoperative spinal cord injury in the repair of extent I and II thoracoabdominal aortic aneurysm.
Assuntos
Aneurisma da Aorta Torácica/cirurgia , Líquido Cefalorraquidiano , Drenagem , Espaço Epidural , Hipotermia Induzida/métodos , Idoso , Aneurisma da Aorta Torácica/patologia , Procedimentos Cirúrgicos Cardiovasculares/efeitos adversos , Procedimentos Cirúrgicos Cardiovasculares/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/prevenção & controle , Isquemia do Cordão Espinal/etiologia , Isquemia do Cordão Espinal/prevenção & controleRESUMO
OBJECTIVES: The purpose of this study is to evaluate usefulness of perfusion cooling for regional spinal cord hypothermia during most or all of thoracic or thoracoabdominal aneurysm repair. METHODS: From 1987 to 2003, 103 patients underwent most or all of thoracic or thoracoabdominal aneurysm repair. Forty-eight patients underwent operation using distal aortic perfusion, mild hypothermia and segment sequential repair (group MH). Fifty-five patients underwent the same operation as group MH except epidural perfusion cooling and drainage of cerebrospinal fluid (CSF) [group EC & CSFD]. The aorta was replaced sequentially in segment and several paris of intercostal and lumbar arteries were reconstructed in 2 groups. RESULTS: Cardiopulmonary bypass time of group MH and group EC & CSFD was averaged 235 and 241 minutes, respectively. The lowest CSF temperature in group EC & CSFD was averaged 24.7 degrees C, and the difference between nasopharyngeal and CSF temperature was averaged 6.4 degrees C. The rate of spinal cord injury of group MH and EC & CSFD was 10.4% and 3.6%, respectively. Hospital mortality of group MH and EC & CSFD was 8.3% and 5.5%, respectively. The incidence of spinal cord injury and hospital mortality of group EC & CSFD were decreased compared to them of group MH. CONCLUSION: We conclude that the perfusion cooling of epidural space and CSF drainage are effective method in reducing postoperative spinal cord injury.
Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Drenagem/métodos , Espaço Epidural , Hipotermia Induzida/métodos , Perfusão/métodos , Assistência Perioperatória , Complicações Pós-Operatórias/prevenção & controle , Isquemia do Cordão Espinal/prevenção & controle , Adulto , Idoso , Idoso de 80 Anos ou mais , Implante de Prótese Vascular , Ponte Cardiopulmonar , Líquido Cefalorraquidiano , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
To clarify (1) the localization of flotillins in human brain tissue and (2) the relationship between senile plaque formation and flotillins localization, we performed Western blotting and immunohistochemical analysis. Flotillins 1 and 2 were shown as 48 and 42 kDa bands, respectively, in human brain. The cerebral cortex showed a broad band-like labeling in entire layers. Flotillins were abundant in pyramidal neurons and astrocytes in the white matter. The intensity of the band-like labeling throughout the cortex became stronger with the development of senile plaque formation, and strongest in Alzheimer's disease. These findings suggest that flotillins are associated with progression of Alzheimer pathology.
Assuntos
Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Proteínas de Membrana/metabolismo , Adulto , Idoso , Astrócitos/metabolismo , Astrócitos/patologia , Cerebelo/patologia , Cerebelo/fisiopatologia , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Progressão da Doença , Humanos , Pessoa de Meia-Idade , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Células Piramidais/metabolismo , Células Piramidais/patologiaRESUMO
The purpose of this research was to evaluate the use of a rotating fluidized-bed granulator to produce acetaminophen granules with sufficient binding force between particles and good plasticity in tablets. Ethenzamide and ascorbic acid were used to compare the relationship between granulation and the sample wetness. It was revealed that a blade rotation rate of 300 rpm, inlet air flow rate of 42 m3/hr, and spraying pressure of 1.5 kg/cm3 produced tablets with the best properties. The granule and tablet properties of ethenzamide and ascorbic acid were compared to those of acetaminophen. These compounds showed different wetting behaviors with water and different compression behaviors. With an increase in medicament content, tablet hardness increased except for the ascorbic acid formulation. Capping and sticking were observed in acetaminophen and in ascorbic acid, respectively, and acetaminophen and ethenzamide showed prolonged disintegration time.
Assuntos
Acetaminofen/química , Analgésicos não Narcóticos/química , Acetaminofen/administração & dosagem , Analgésicos não Narcóticos/administração & dosagem , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/química , Química Farmacêutica , Composição de Medicamentos , Dureza , Tamanho da Partícula , Porosidade , Pós , Salicilamidas/administração & dosagem , Salicilamidas/química , Solubilidade , Comprimidos , Resistência à TraçãoRESUMO
We describe embryonic development of the Bombyx silk gland. To extend the analysis further we isolated a Bombyx counterpart gene of the Drosophila trachealess (trh) gene. Bombyx trh encodes a protein of 849 amino acids. When compared with the amino acid sequence of Drosophila trh, the identity of Bombyx bHLH, PAS-A and PAS-B domains is 100%, 97%, and 80%, respectively. Northern blot analysis revealed the presence of a single Bombyx trh transcript of 5.4 kb. We analyzed the expression pattern of the Bombyx trh transcript during embryogenesis by in situ hybridization. Bombyx trh mRNA was first detected in the tracheal primordial cells at around embryonic stage 18. Thereafter levels of Bombyx trh mRNA increased, and the high expression level was maintained until hatching. At embryonic stage 19 the transcript was also detected in the posterior basal region of the labial segment from where the silk gland invaginates. By the blastokinesis stage (around stage 23), the silk gland was lengthened, and, interestingly, the Bombyx trh transcript was restricted to the anterior silk gland. These results suggest that Bombyx trh plays a role in the formation of the trachea and the anterior silk glands.
Assuntos
Bombyx/embriologia , Bombyx/genética , Proteínas de Drosophila , Glândulas Exócrinas/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Proteínas com Domínio T/genética , Fatores de Transcrição/genética , Proteínas de Xenopus , Animais , Sequência de Bases , Clonagem Molecular , Primers do DNA , Drosophila/genética , Embrião não Mamífero/fisiologia , Indução Embrionária , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Proteínas com Domínio T/química , Transcrição GênicaRESUMO
In this report we describe the initial characterization of murine, human, and Drosophila hesr-1 (for hairy and enhancer of split related-1) a novel evolutionary conserved family of hairy/enhancer of split homologs. Hesr-1 cDNAs display features typical of hairy and enhancer of split-type bHLH proteins including a N-terminal bHLH domain a conserved orange domain immediately C-terminal to the bHLH region. Despite their similarity to known hairy/enhancer of split homologs, hesr-1 cDNAs are divergent members of the hairy and enhancer of split bHLH family since the degree of sequence identity within the bHLH and their nearest homologs are relatively low. Moreover, the tetrapeptide motif, WRPW, which is found in all hairy and enhancer of split family members, is not present in hesr-1. Rather, a variant of this motif, YRPW, is found. Analysis of embryonic murine hesr-1 expression by in situ hybridization reveals strong expression in the somitic mesoderm, the central nervous system, the kidney, the heart, nasal epithelium, and limbs indicating a role for hesr-1 in the development of these tissues. Like the enhancer of split cDNAs in Drosophila, we show that hesr-1 expression depends critically on signaling through the notch pathway in murine embryos, suggesting that aspects of hesr-1 regulation and function might also be evolutionary conserved.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Drosophila , Drosophila/genética , Proteínas de Insetos/genética , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos , DNA Complementar , Proteínas de Ligação a DNA/metabolismo , Desenvolvimento Embrionário e Fetal/genética , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Proteínas de Insetos/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Dados de Sequência Molecular , Receptores Notch , Proteínas Repressoras/metabolismo , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Fatores de Transcrição/metabolismoRESUMO
A novel enteric coating method was developed. This method involves direct feeding of coating polymer powder and simultaneous spraying of plasticizing agent, without either organic solvent or water, using a centrifugal granulator, fluidized bed, or tablet-coating machine. For film formation, a curing step was then necessary; this involved spraying a small amount (3-8% of core weight) of water or hydroxypropyl methylcellulose solution, followed by heating. Hydroxypropyl methylcellulose acetate succinate was used as the enteric coating polymer, and a combination of triethyl citrate and acetylated monoglyceride was used for plasticization. The coated beads and tablets were evaluated for gastric resistance, intestinal disintegration, and stability, in comparison with beads and tablets from a conventional aqueous coating with the same enteric polymer. The new method required a higher coating amount for gastric resistance compared with the conventional coating, but the processing time was dramatically reduced. The results show that this dry coating method is applicable to the preparation of enteric-coated beads and tablets using commercially available lab-scale apparatus.
Assuntos
Metilcelulose/análogos & derivados , Plastificantes , Comprimidos com Revestimento Entérico , Estabilidade de Medicamentos , Microscopia Eletrônica de Varredura , Microesferas , Tamanho da Partícula , PósRESUMO
Embryonic and larval expression patterns of the sericin-1 gene and its presumed transcription factor, SGF-3/POU-M1, in the silk gland were analyzed by in situ hybridization and immunohistochemistry. The sericin-1 transcripts were first detected at embryonic stage 26 in an increasing gradient pattern in the middle and posterior part of the middle silk gland (MSG), while at the same stage the SGF-3/POU-M1 was already present in the entire anterior silk gland (ASG) and in the MSG but with a decreasing gradient pattern. The latter expression pattern was consistently maintained through all larval stages, while the sericin-1 expression was detected during the feeding stages but disappeared at the molting stages. These observations suggest that, although the SGF-3/POU-M1 was proposed to be a positive transcription factor for the sericin-1 gene, the protein might function in a negative manner on sericin-1 gene transcription. Alternatively, it is also possible that the sericin-1 gene might require another unidentified factor or mediator for in vivo transcription.
Assuntos
Bombyx/crescimento & desenvolvimento , Bombyx/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos , Peptídeos Cíclicos/genética , Fatores de Transcrição/metabolismo , Animais , Northern Blotting , Western Blotting , Imuno-Histoquímica , Hibridização In Situ , Larva , Fatores do Domínio POU , Sericinas , Fatores de Tempo , Distribuição TecidualRESUMO
Pellet film coating has very limited applicability compared with tablet film coating, because of the problem of sticking during fluidized bed operation. We have prepared an extremely low viscosity methylcellulose (MC) (4 mPa.s), and examined its solution and film properties and its suitability for pellet film coating. MC lost its adhesiveness at a relatively high moisture content and pellet film coating could be achieved without agglomeration of the pellets within a reasonable operating time. The coated pellets were covered with a continuous film of MC, and drug release from the coated pellets was as rapid as that from the core. These findings suggest that MC (4 mPa.s) is applicable for pellet film coating in an aqueous system.
Assuntos
Metilcelulose/química , Géis , Solubilidade , Soluções , ViscosidadeRESUMO
Dorsal-ventral limb patterning in vertebrates is thought to be controlled by the LIM-homeodomain protein Lmx1b which is expressed in a spatially and temporally restricted manner along the dorsal-ventral limb axis. Here we describe the phenotype resulting from targeted disruption of Lmx1b. Our results demonstrate that Lmx1b is essential for the specification of dorsal limb fates at both the zeugopodal and autopodal level with prominent phenotypes including an absence of nails and patellae. These features are similar to those present in a dominantly inherited human condition called nail patella syndrome (NPS), which also has renal involvement. Mouse Lmx1b maps to a region syntenic to that of the NPS gene, and kidneys of Lmx1b mutant mice exhibit pathological changes similar to that observed in NPS (refs 5,6). Our results demonstrate an essential function for Lmx1b in mouse limb and kidney development and suggest that NPS might result from mutations in the human LMX1B gene.
Assuntos
Proteínas de Homeodomínio/genética , Rim/anormalidades , Deformidades Congênitas dos Membros/genética , Síndrome da Unha-Patela/genética , Animais , DNA Complementar , Proteínas de Homeodomínio/química , Humanos , Proteínas com Homeodomínio LIM , Camundongos , Camundongos Mutantes , Microscopia Eletrônica de Varredura , Fatores de TranscriçãoRESUMO
In this study, acetaminophen, ascorbic acid, and ethenzamide were selected as model drugs for tableting granules. Agitation and fluidized-bed granulation were carried out at three drug contents of 30, 50, and 70%. Compared with agitation granulation, granules made by fluidized-bed granulation showed superior compressibility with wide formulation allowance for drug type and amount. Fluidized-bed granulation resulted in less granule hardness and greater plastic deformability. The granules had considerable compactness and for tablets containing 70% ethenzamide, prolonged disintegration and dissolution times were noted. These are typical features of granules produced by fluidized-bed granulation.
Assuntos
Comprimidos/normas , Acetaminofen/química , Ácido Ascórbico/química , Composição de Medicamentos , Excipientes , Testes de Dureza , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Pós , Salicilamidas/química , SolubilidadeRESUMO
Hydroxypropyl methylcellulose (HPMC) was selected as a base polymer to develop novel enteric coating agents for acid protection which can dissolve at pH around 4, and was modified with trimellitic acid or maleic acid at various degrees of substitution. These carboxylic acids have higher dissociation constants and higher solubility in water than the carboxylic acids of existing enteric coating polymers. The synthesized polymers were micronized and dispersed in aqueous medium to determine their pKa values by potentiometric titration. The pH of dissolution and the water vapor permeability of the cast films prepared from organic solutions were also evaluated. Hydroxypropyl methylcellulose trimellitate (HPMCT) showed good acid resistance, and the pH at which it dissolves can be controlled in the range of pH 3.5 to 4.5 by varying the content of trimellityl groups and the methoxyl substitution of the base polymer.
Assuntos
Celulose/química , Comprimidos com Revestimento Entérico/química , Concentração de Íons de HidrogênioRESUMO
Homeotic selector genes determine the identity of each segment and induce the differentiation of segment-specific organs. To analyze how the silk glands of the lepidopteran, Bombyx mori, develop, we cloned and identified two genes that encode the homeodomain and its flanking regions identical to the corresponding regions of Deformed and Sex combs reduced. Using in situ hybridization and immunohistochemistry, we analyzed the expression patterns of these genes during Bombyx embryogenesis. Bombyx Deformed is expressed in the mandibular and maxillary segments, whereas expression of Bombyx Sex combs reduced is first limited to the labial segment and at later stages extended to the anterior part of the prothoracic segment. The expression of Bombyx Sex combs reduced then disappears from the invaginating placodes of silk glands where expression of Bombyx fork head/SGF-1 follows. In the Nc/Nc mutant embryos, which lack the 3' end region of Bombyx Antennapedia, in addition to the expression in the labial segment, the Bombyx Sex combs reduced is expressed ectopically in the thoracic and abdominal regions, and Bombyx fork head/SGF-1 is also ectopically expressed in the T1, T2, and T3 segments, resulting the ectopic induction of the silk gland invaginations. These results suggest that Bombyx homeobox genes such as the Bombyx Deformed and Sex combs reduced are associated with determination of the segment identities and Bombyx Sex combs reduced is involved in the induction of silk gland development.
Assuntos
Bombyx/embriologia , Proteínas de Drosophila , Regulação da Expressão Gênica no Desenvolvimento/genética , Genes de Insetos/genética , Proteínas de Insetos/fisiologia , Glândulas Salivares/embriologia , Fatores de Transcrição , Sequência de Aminoácidos , Animais , Bombyx/genética , Sondas de DNA/química , Drosophila/genética , Embrião não Mamífero/química , Embrião não Mamífero/embriologia , Imuno-Histoquímica , Hibridização In Situ , Proteínas de Insetos/genética , Dados de Sequência MolecularRESUMO
The transcriptional modulator in the fibroin gene intron is composed of multiple octamer-like AT-rich elements, to which several specific DNA-binding proteins named fibroin-modulator-binding proteins (FMBPs) bind. Three major FMBPs in the silk gland were characterized. Two of them (FMBP-2 and -3) were identified as a Fork head homologue (Bm Fkh) and a POU-domain protein (POU-M1) respectively. These factors were expressed in the silk gland with distinct temporal- and spatial-specificities during late larval development as well as during embryogenesis, and did not correlate directly with fibroin gene expression. The other (FMBP-1) appeared to correlate with the expression of the fibroin gene for temporal- and spatial-specificity. These FMBPs also bind to the elements in the upstream modulator. Transcriptional enhancement by both modulators was inhibited by binding competition for these factors with oligonucleotides. These results suggest that expression of the fibroin gene is controlled by co-ordination of these factors with distinct specificities during silk-gland development.
Assuntos
Bombyx/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fibroínas/genética , Proteínas de Insetos , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sítios de Ligação/genética , Ligação Competitiva , Bombyx/embriologia , Clonagem Molecular , Pegada de DNA , Sondas de DNA/química , Fatores de Transcrição Forkhead , Regulação da Expressão Gênica no Desenvolvimento/genética , Hormônios de Inseto/metabolismo , Fatores do Domínio POU , Análise de Sequência , Ativação Transcricional/fisiologiaRESUMO
The expression pattern of the POU-M1/SGF-3 gene during Bombyx embryogenesis has been analysed using in situ hybridization and immunohistochemistry. At the early embryo retraction stage, both the transcripts and protein were first detected in precursor cells of the prothoracic glands in the labial segment, in the oenocytes in the A1-A8 segments and in invaginated regions in the mandibular and maxillary segments. The invaginated regions in the mandibular segment develop into the abductor plates in the lateral anterior region and the adductor plates in the posterior region. From the latter plates, the salivary glands elongate. The invaginated regions in the maxillary segment develop into the corpora allata in the anterior region and the subbuccal glands in the posterior region, which unite with tissues of the anterior region of the mandibular segment at later stages. After the embryo retraction stage, the transcripts and protein products also become detectable in the silk gland invagination points and, after the blastokinesis stage, the products are restricted to the entire anterior silk glands and to the anterior and middle parts of the middle silk glands. Expression can also be detected in a part of the hindgut, in the tracheal system and in some cells of the central nervous system. These results indicate that POU-M1/SGF-3 might play roles in the development of the silk glands, nervous system, tracheal system and other organs like the prothoracic glands and oenocytes.
RESUMO
BACKGROUND: Abundant availability of homeotic mutants in Bombyx mori provides us with clues to study the body plan of the silkworm. Previous studies indicated that the ECa/ECa and EN/EN embryos, which reveal drastic morphological changes (Itikawa 1943, 1952) lack the homologue of abd-A and the homologues of abd-A and Ubx, respectively (Ueno et al. 1992). It will be interesting to characterize a mutant named Nc, the locus of which was mapped about 1.4 cm apart from the E loci (Itikawa 1944, 1952). RESULTS: In the present study we cloned and identified the Bombyx Antennapedia cDNA from a library of larval middle silk gland. The developmental expression patterns of the Bombyx Antennapedia were analysed in embryos and larval middle silk glands. We found the Bombyx Antennapedia mRNA of the Nc mutant lacks the homeobox region and its downstream region. This defect comes from a corresponding deletion on the Nc chromosome. Development of the Nc/Nc embryos terminates at stage 26, revealing a transformation of the prothoracic legs into antennae, milder changes in the mesothoracic legs, compression between the prothoracic and mesothoracic segments as well as in the gnathocephalon region, and a severe growth suppression of the silk glands. CONCLUSIONS: These results give a molecular basis and detailed morphological abnormalities of the Nc mutant known since 1944.
Assuntos
Bombyx/genética , Genes Homeobox , Genes de Insetos , Proteínas de Homeodomínio/genética , Proteínas Nucleares , Fatores de Transcrição , Sequência de Aminoácidos , Animais , Proteína do Homeodomínio de Antennapedia , Sequência de Bases , Bombyx/embriologia , Bombyx/crescimento & desenvolvimento , Clonagem Molecular , DNA Complementar/genética , Regulação da Expressão Gênica no Desenvolvimento , Larva/metabolismo , Dados de Sequência Molecular , Mutação , Fases de Leitura Aberta , Fenótipo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de AminoácidosRESUMO
The Drosophila Fork head protein participates in salivary gland formation, since salivary glands are missing in fork head embryos. Here we show that the fork head encoded protein binds to an upstream regulatory region of the larval salivary gland glue protein gene Sgs3. Mobility shift assay in the presence of an anti-Fork head antibody demonstrated that the Fork head factor interacts with the TGTTTGC box shown to be involved in tissue-specific Sgs3 expression. Experiments employing a set of oligonucleotide competitors revealed that Fork head binding was prevented by the same single base substitutions that were previously shown to interfere with the TGTTTGC element function in vivo. Furthermore, the anti-Fork head antibody bound to >60 sites of polytene chromosomes, including the puffs of all Sgs genes and Fork head protein was detected in the nuclei of salivary glands of larvae of all examined stages. These data provide experimental evidence for the hypothesis that the protein encoded by the fork head gene is required initially for salivary gland formation and is utilized subsequently in the control of larval genes specifically expressed in this organ.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas do Grude Salivar de Drosophila/genética , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação , Bombyx , Cromossomos , DNA , Fatores de Transcrição Forkhead , Larva , Masculino , Dados de Sequência Molecular , Coelhos , Sequências Reguladoras de Ácido Nucleico , Glândulas Salivares/metabolismoAssuntos
Bombyx/embriologia , Bombyx/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Desenvolvimento Embrionário e Fetal/genética , Dados de Sequência Molecular , Fatores do Domínio POU , Peptídeos Cíclicos/genética , Sericinas , Transcrição Gênica/genéticaRESUMO
T3 and T7 phages package recombinant plasmids carrying DNA necessary for DNA packaging (the pac sequences) of T3 and T7, respectively. Packaging is specific between T3 and T7. The pac sequence has a bipartite structure, consisting of target sequences for processing of concatemeric DNA (pac C) and its left side flanking sequence containing a promoter for phage RNA polymerase (pac B). To determine the sequences responsible for the specificity of plasmid DNA packaging, plasmids chimeric for the pac B and pac C sequences of T3 and T7 were constructed. Analysis of packaging of the chimeric plasmid DNAs showed that pac B is responsible for the packaging specificity of T3 and T7 DNAs. Plasmids carrying the genetic right end of T3 and T7 DNA interfered with the growth of T3 and T7 phages, respectively. Interference was specific between T3 and T7. pac B and sequences between pac B and pac C, but not pac C, were responsible for the interference. The specificity of interference was determined by pac B and sequences responsible for interference were partially defined.
Assuntos
Bacteriófago T3/genética , Bacteriófago T7/genética , DNA Viral/fisiologia , Montagem de Vírus/genética , Bacteriófago T3/fisiologia , Bacteriófago T7/fisiologia , Sequência de Bases , DNA Recombinante , DNA Viral/química , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Plasmídeos , Interferência ViralRESUMO
The embryonic expression of Bombyx fkh/SGF-1 gene has been analysed using in situ hybridization and immunohistochemistry. Both transcripts and protein were first detected in the most anterior and posterior regions at the time of germ anlage formation, and were successively expressed in the foregut and hindgut at later stages. A weaker expression was also detected in the elongated midgut. By the time embryo retraction was finished transcripts and protein were also detectable in the invaginated whole silk glands, and after the blastokinesis stage the products were restricted to the middle and posterior silk glands achieving a state required for the SGF-1 distribution for later stages. Expression could also be detected in the central and peripheral nervous systems. From these observations, we propose that Bombyx Fkh/SGF-1 may play a role in organogenesis processes such as those of the gut, silk glands, and nervous systems, act as a region specific homeotic gene, and in spite of clear embryonic developmental differences between Drosophila and Bombyx, two terminals may be determined by region specific genes such as Bombyx fkh/SGF-1 as opposed to segmental development.