RESUMO
The differentiation of myoblasts to form functional muscle fibers is a consequence of interactions between the mesoderm and ectoderm. The authors examine the role of segment identity in directing these interactions by studying the role of Hox genes in patterning adult muscles in Drosophila. Using the 'four-winged fly' to remove Ultrabithorax function in the developing adult, the authors alter the identity of the ectoderm of the third thoracic segment towards the second and show that this is sufficient to inductively alter most properties of the mesoderm-myoblast number, molecular diversity, and migration pattern-to that of the second thoracic segment. Not all aspects of myogenesis are determined by the segment identity of the ectoderm. The autonomous identity of the mesoderm is important for choosing muscle founder cells in the correct segmental pattern. The authors show this by removal of the function of Antennapedia, the Hox gene expressed in the mesoderm of the third thoracic segment. This results in the transformation of founder cells to a second-thoracic pattern. The authors also report a role for the nervous system in later aspects of muscle morphogenesis by specifically altering Ultrabithorax gene expression in motor neurons. Thus, ectoderm and mesoderm segment identities collaborate to direct muscle differentiation by affecting distinct aspects of the process.
Assuntos
Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Genes Homeobox/fisiologia , Neurônios Motores/fisiologia , Desenvolvimento Muscular/genética , Músculo Estriado/embriologia , Animais , Padronização Corporal/genética , Diferenciação Celular/genética , Movimento Celular/genética , Drosophila melanogaster/citologia , Modelos Animais , Neurônios Motores/citologia , Músculo Estriado/citologia , Músculo Estriado/inervação , Mioblastos/citologia , Mioblastos/fisiologiaRESUMO
The class II fusion proteins of the alphaviruses and flaviviruses mediate virus infection by driving the fusion of the virus membrane with that of the cell. These fusion proteins are triggered by low pH, and their structures are strikingly similar in both the prefusion dimer and the postfusion homotrimer conformations. Here we have compared cholesterol interactions during membrane fusion by these two groups of viruses. Using cholesterol-depleted insect cells, we showed that fusion and infection by the alphaviruses Semliki Forest virus (SFV) and Sindbis virus were strongly promoted by cholesterol, with similar sterol dependence in laboratory and field isolates and in viruses passaged in tissue culture. The E1 fusion protein from SFV bound cholesterol, as detected by labeling with photocholesterol and by cholesterol extraction studies. In contrast, fusion and infection by numerous strains of the flavivirus dengue virus (DV) and by yellow fever virus 17D were cholesterol independent, and the DV fusion protein did not show significant cholesterol binding. SFV E1 is the first virus fusion protein demonstrated to directly bind cholesterol. Taken together, our results reveal important functional differences conferred by the cholesterol-binding properties of class II fusion proteins.
Assuntos
Alphavirus/patogenicidade , Colesterol/metabolismo , Flavivirus/patogenicidade , Fusão de Membrana/fisiologia , Proteínas Virais de Fusão/metabolismo , Alphavirus/genética , Alphavirus/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Cricetinae , Culicidae , Vírus da Dengue/metabolismo , Vírus da Dengue/patogenicidade , Flavivirus/genética , Flavivirus/metabolismo , Mutação , Vírus da Floresta de Semliki/metabolismo , Vírus da Floresta de Semliki/patogenicidade , Sindbis virus/metabolismo , Sindbis virus/patogenicidade , Proteínas Virais de Fusão/genética , Vírus da Febre Amarela/metabolismo , Vírus da Febre Amarela/patogenicidadeRESUMO
Metal nanoparticles are widely used for the delivery and targeting of pharmaceutical, therapeutic and diagnostic agents in cancer therapy in recent years. The multifunctional nanoparticles constructed currently are supposed to show superior effects on cancer cells. This study was conducted to observe the difference between the effect of a biologically important peptide, silver (AgNPs) and gold (AuNPs) nanoparticles and their conjugates on two different cancer cells. Peptide (Boc-L-DP-L-OMe) was acquired from different sources and subjected to conjugation with biosynthesized gold and silver nanoparticles under standard conditions. These conjugates were tested against the colon cancer (HT-29) and breast cancer (MDA MB-231) cell lines. The results clearly depicted the improved activity of nanoparticles in the form of conjugates. Fluorescent dye microscopy and DNA fragmentation assay substantiate the fact that the conjugated nanoparticles cause higher level of disintegration of DNA in cells that consecutively damages and causes apoptosis due to lethality.
RESUMO
Absence seizures are often associated with impaired or loss of consciousness clinically proved to have an impact on motor and cognitive abnormalities of the nerve cells of the brain. Seizure admits several etiopathophysiological events leading to several neurofunctional changes in the reticulothalamocortical circuitry zones of the central nervous system. This paves the episodes of absence seizure events. A clinical case report of absence seizure in a 25 years age adult patient came to the hospital with impaired consciousness. The brain magnetic resonance imaging scanning of the patient detected a small focal flair hypertensive area in the right parasellar region close to cavernous sinus with mild flair hypersensitivity in the left cavernous sinuses, right maxillary, and ethmoid sinusitis. The electroencephalogram of the brain showed normal waves with electrode artifacts was observed. The patient was confirmed with absence seizures, and he was treated with oxcarbazepine 150 mg twice daily. The patient was recovered from seizure and discharged with medications. He was called for follow-up examination once in 3-month period.
RESUMO
We exploited the silkworm Bombyx mori for the production of recombinant canine interferon-alpha (CaIFN-alpha). The recombinant baculovirus harboring canine interferon gene was rapidly generated by the BmNPV/Bac-to-Bac system that was recently developed. In B. mori-derived cell lines, the expression of the recombinant protein reached maximal levels around 72-96 h post-infection. For the isolation of the expressed recombinant protein from B. mori larvae, the whole bodies of the infected larvae were homogenized, and the expressed protein was purified by affinity chromatography. Based on the fact that the recombinant CaIFN-alpha showed two bands on the sodium dodecyl sulfate polyacrylamide gel electrophoresis pattern, the expressed protein was thought to be glycosylated. The rCaIFN-alpha yield was about 528 microg per larva, showing that the expression in silkworm was successful. Furthermore, the recombinant protein was proven to be able to inhibit the infection of Madin-Darby canine kidney cells by the vesicular stomatitis virus, indicating that it is biologically active in vitro. The method established in this study provides an efficient way to produce a large amount of CaIFN-alpha and paves the way for further utilization of this protein as a therapeutic agent or vaccine adjuvant in dogs.
Assuntos
Bombyx/genética , Bombyx/metabolismo , Interferon-alfa/biossíntese , Proteínas Recombinantes/biossíntese , Animais , Baculoviridae/genética , Linhagem Celular , Sobrevivência Celular , Cromatografia de Afinidade , Cães , Eletroforese em Gel de Poliacrilamida , Vetores Genéticos , Glicosilação , Interferon-alfa/genética , Interferon-alfa/isolamento & purificação , Larva/genética , Larva/metabolismo , Dados de Sequência Molecular , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Infecções por Rhabdoviridae/imunologia , Análise de Sequência de DNA , Vesiculovirus/imunologiaRESUMO
Physalis mottle tymovirus (PhMV) is a small spherical plant virus with its RNA genome encapsidated in a protein shell made of 180 identical coat protein (CP) subunits. The amino acid residues involved in two interfacial salt bridges, Asp-83/Arg-159 and Arg-68/Asp-150 and Lys-153, were targeted for mutagenesis with a view to delineate the role of interfacial ionic interactions in the subunit folding and assembly of the virus. R159A and D83A-R159A recombinant CP (rCP) mutants formed stable T = 3 capsids, indicating that the D83-R159 interfacial salt bridge is dispensable for the folding and assembly of PhMV. However, D150A and R68Q-D150A mutant rCPs were present in the insoluble fraction, suggesting that the R68-D150 interfacial salt bridge is crucial for subunit folding and assembly. Similarly, K153Q, D83A-K153Q, and H69A-K153Q mutant rCPs were present in the insoluble fraction. Interestingly, the R68Q-D150A, D83A-K153Q, and H69A-K153Q double mutant rCPs could be refolded into partially folded soluble heterogeneous aggregates of 14-16 S. The results further confirm our earlier observation that subunit folding and assembly are concerted events in PhMV.