kDa Molecular Weight (kda + molecular_weight)

Distribution by Scientific Domains

Selected Abstracts

Expression and immunocytochemical analysis of Autographa californica nucleopolyhedrovirus (AcMNPV) orf74 gene

INSECT SCIENCE, Issue 5 2006
Abstract Autographa californica nucleopolyhedrovirus orf74 (Ac74) is located between 62 311 and 63 108bp in the AcMNPV genome, which encodes 265 amino acid residues with a predicted 31 kDa molecular weight. The homologues of Ac74 were searched using BLASTP in protein databases, GenBank/EMBL and SWISS-PROT. The result revealed that deduced Ac74 protein was homologous to the predicted products from 10 lepidoptera NPV ORFs. The multiple sequence alignments of Ac74 and its 10 homologues manifested only one amino acid residue was completely conserved. The transcript analysis revealed that the transcript of Ac74 was detected from 24,72 hours post-infection (hpi). The product of Ac74 was detected at 24 hpi and lasted until 72 hpi by Western blot using anti-Ac74 antiserum, consistent with reverse transcriptase polymerase chain reaction results. These results suggested Ac74 was expressed during the later stages of infection. The product of Ac74 was 31 kDa in size, consistent with predicted molecular weight. The subcellular localization of Ac74 proteins manifested Ac74 protein in the cytoplasm, and was hardly present in the nucleus at 24 hpi. The fluorescence was also observed in polyhedra, except cytoplasm at 72 hpi. Together, Ac74 is a functional protein with 3 1kDa molecular weight and is located in the cytoplasm and the polyhedra. [source]

Analysis of a late gene, orf101 from Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus

INSECT SCIENCE, Issue 5 2005
Abstract Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus open reading frame 101 (ha101) is 762 nts in length and encodes a 254 amino acid peptide with predicted 29 kDa molecular weight. The homologues of ha101 were explored using BLASTP searching tool in the updated GenBank/EMBL and SWISS-PROT databases. The results showed that the homologues of ha101 were present in all the completely sequenced lepidopteran nucleopolyhedroviruses and granuloviruses, suggesting that ha101 might be a functional gene associated with their lepidopteran hosts. Sequence alignment of ha101 and its homologues revealed that 10 amino acids were completely conserved. RT-PCR analysis of ha101 manifested that the transcript of ha101 was first detected at 24 hpi and remained detectable at up to 122 hpi, suggesting that ha101 was transcribed during late stages of infection. Ha101 was expressed using Bac to Bac system in Tn5B-1-4 cells. The product of ha101 expressed in Tn5B-1-4 cells was approximately 29 kDa, consistent with the predicted molecular weight, and the results were confirmed by western blot analysis. The subcellular localization indicated that ha101 was aggregated along nuclear envelope during the early stages of infection and spread out to the entire nucleus including virogenic stroma in late stages of infection, suggesting that ha101 may play a specific role in virion assembly process or virogenic stroma arrangement. [source]


ABSTRACT The sae operon is a key regulator in Staphylococcus aureus, which is known as an important infective and toxigenic bacterial pathogen. For the exploration of virulence factors expressed in the secreted exoprotein fraction are being controlled by sae operon, the relationship between the sae locus and exoproteins was investigated in this study. The homologous recombination vector pBT2,sae was constructed and the sae deletion mutant strain was successfully obtained. The results showed that the sae locus played an important role in the production of thermonucleases and other exoproteins. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed different exoprotein profiles between parent strain and mutant strain, in which three bands were visibly weakened. The results revealed that sae locus was involved in the regulation on exoproteins, some of which play a known fundamental role in the virulence of S. aureus. PRACTICAL APPLICATIONS This study presents that knocking out the sae gene locus in a specific Staphylococcus aureus strain results in reduced thermonuclease action, and also in reduced levels of proteins in the vicinity of 42 and 32 kDa molecular weight in sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) gels, indicating that their production is dependent on the sae locus. Practically, these proteins are associated with virulence traits, and with the pathogen's response to the environment and in potential hosts, which could be helpful for understanding the pathogenicity of S. aureus and also for further studies on the role of selected genes in the pathogenicity of S. aureus. [source]

Endopeptidase Isoenzyme Characteristics in Cucumis sativus Leaves During Dark-induced Senescence

Peng Zhang
Abstract The changes and characteristics of endopeptidase (EP) isoenzymes in cucumber (Cucumis sativus L.) leaves during dark-induced senescence were investigated by activity staining after gradient-polyacrylamide gel electrophoresis (G-PAGE) containing co-polymerized gelatin as substrate. The results showed that both the chlorophyll and the protein contents of leaves were decreased, and the protein degradation was correlated with the increase of proteolytic activity during the course of leaf senescence. Meanwhile, nine cucumber endopeptidases isoenzymes (CEP) with 140, 120, 106, 94, 76, 55, 46, 39 and 35 kDa molecular weights were detected. Four of these, CEP2, 3, 4 and CEP9 appeared all the time, but the changes of the activity were different during incubation. Another four CEPs (CEP5, 6, 7 and CEP8) whose activities increased with dark-induced time were only detected in senescent leaves. Furthermore, the biochemical properties of these nine CEP were also characterized. All the CEPs had high activities from 35 C to 45 C, and the optimum temperature was found to be 40 C. However, the activities of CEPs were not detected below 25 C or over 60 C. The activity bands appeared at a wide range of pH from 5.0 to 9.0, but the optimum pH was found at 7.0. No CEPs were detected at pH 4 or pH 10. By inhibition analysis we concluded that CEP2, 3, 4 and CEP9 were serine endopeptidases and CEP6 was a kind of cysteine protease. It is suggested that serine endopeptidases might play a major role in cucumber leaf senescence, and for the first time, six senescence-related endopeptidases (CEP1, 5, 6, 7, 8 and 9) were found in cucumber leaves. [source]