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Amino Acid Sequence Comparison (amino + acid_sequence_comparison)
Selected AbstractsMolecular and Biochemical Evidence for Phenylpropanoid Synthesis and Presence of Wall-linked Phenolics in Cotton FibersJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 7 2009Ling Fan Abstract The mature cotton (Gossypium hirsutum L.) fiber is a single cell with a typically thickened secondary cell wall. The aim of this research was to use molecular, spectroscopic and chemical techniques to investigate the possible occurrence of previously overlooked accumulation of phenolics during secondary cell wall formation in cotton fibers. Relative quantitative reverse transcription-polymerase chain reaction analysis showed that GhCAD6 and GhCAD1 were predominantly expressed among seven gene homologs, only GhCAD6 was up-regulated during secondary wall formation in cotton fibers. Phylogenic analysis revealed that GhCAD6 belonged to Class I and was proposed to have a major role in monolignol biosynthesis, and GhCAD1 belonged to Class III and was proposed to have a compensatory mechanism for monolignol biosynthesis. Amino acid sequence comparison showed that the cofactor binding sites of GhCADs were highly conserved with high similarity and identity to bona fide cinnamyl alcohol dehydrogenases. The substrate binding site of GhCAD1 is different from GhCAD6. This difference was confirmed by the different catalytic activities observed with the enzymes. Cell wall auto-fluorescence, Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and chemical analyses confirmed that phenolic compounds were bound to the cell walls of mature cotton fibers. Our findings may suggest a potential for genetic manipulation of cotton fiber properties, which are of central importance to agricultural, cotton processing and textile industries. [source] Modulation of perch connexin35 hemi-channels by cyclic AMP requires a protein kinase A phosphorylation siteJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2003Georgia Mitropoulou Abstract Retinal neurons are coupled via gap junctions, which function as electrical synapses that are gated by ambient light conditions. Gap junctions connecting either horizontal cells or AII amacrine cells are inhibited by the neurotransmitter dopamine, via the activation of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway. Fish connexin35 (Cx35) and its mouse ortholog, Cx36, are good candidates to undergo dopaminergic modulation, because they have been detected in the inner plexiform layer of the retina, where Type II amacrine cells establish synaptic contacts. We have taken advantage of the ability of certain connexins to form functional connexons (hemi-channels), when expressed in Xenopus oocytes, to investigate whether pharmacological elevation of cAMP modulates voltage-activated hemi-channel currents in single oocytes. Injection of perch Cx35 RNA into Xenopus oocytes induced outward voltage-dependent currents that were recorded at positive membrane potentials. Incubation of oocytes with 8-bromoadenosine 3,,5,-cyclic monophosphate (8-Br-cAMP), a membrane permeable cAMP analog, resulted in a dose-dependent and reversible inhibition of hemi-channel currents at the more positive voltage steps. In contrast, treatment with 8-Br-cAMP did not have any effect on hemi-channel currents induced by skate Cx35. Amino acid sequence comparison of the two fish connexins revealed, in the middle cytoplasmic loop of perch Cx35, the presence of a PKA consensus sequence that was absent in the skate connexin. The results obtained with two constructs in which the putative PKA phosphorylation site was either suppressed (perch Cx35R108Q) or introduced (skate Cx35Q108R) indicate that it is responsible for the inhibition of hemi-channel currents. These studies demonstrate that perch Cx35 is a target of the cAMP/PKA signaling pathway and identify a consensus PKA phosphorylation site that is required for channel gating. © 2003 Wiley-Liss, Inc. [source] Identification and expression analysis of a MYB family transcription factor in the parasitic plant Orobanche ramosaANNALS OF APPLIED BIOLOGY, Issue 2 2007C.I. González-Verdejo Abstract MYB proteins are transcription factors (TFs) involved in the regulation of developmental processes in eukaryotes. A number of MYB genes have been identified from plants, but they have not been studied in parasitic plants. In this work, a member of the R2R3 MYB family of TFs was isolated from a complementary DNA library representing different developmental stages of the parasitic plant Orobanche ramosa. The pattern of expression of the gene was studied by in situ hybridisation. Alignment of the deduced Or-MYB1 protein with members of the MYB family showed the highest overall identity with MYB.Ph3 from petunia (Petunia hybrida), NtMYBAS1/S2 from tobacco (Nicotiana tabacum) and AtMYB101 from Arabidopsis thaliana. Amino acid sequence comparisons of DNA-binding domains showed that Or-MYB1 protein forms a closely related group with these proteins. Transcripts of Or-MYB1 were detected during all the developmental stages analysed, and in situ hybridisation showed that the expression was restricted to the parenchymatic cells proximal to the vascular vessels. These findings are consistent with a role of Or-MYB1 during early stages of development of O. ramosa, probably through the phenylpropanoid pathway. [source] Identification and Molecular Characterization of Viruses Infecting Cucurbits in PakistanJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2004A. Ali Abstract Cucurbits are grown throughout the North-West Frontier Province of Pakistan as summer and winter crops. Plants having mosaic, mottling, chlorosis and leaf distortion symptoms were frequently found in most of the cucurbit fields during the survey. Using dot immunobinding assay, Cucumber green mottle mosaic virus (CGMMV), Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV) and Papaya ringspot virus (PRSV) were found infecting cucurbits. CGMMV was widespread, infecting 46.9% of the samples tested followed by ZYMV (14.8%), WMV (12.5%) and PRSV (7.8%). Multiple infections were common with 42% of the samples being infected with two viruses and 8% with three viruses. The nucleotide sequences of the coat protein (CP) genes of these four viruses were determined and deduced amino acid sequence comparisons revealed 88.3,99% similarity of the ZYMV-Pak isolate with other isolates of ZYMV reported worldwide. The amino acid sequence identity of Pakistani isolates of WMV, CGMMV and PRSV ranged from 96.8 to 98.4%, 98.1 to 99.4% and 79.3 to 84.2%, respectively, with other isolates reported elsewhere. Little variability was observed in the sequences of WMV and CGMMV. ZYMV-Pak was very close to the USA isolate, and the PRSV-Pak isolate was close to Indian isolates of PRSV possibly reflecting the geographical relationship between these isolates. [source] | ||||||||||