Search results for " Homology"
showing 10 items of 633 documents
Characterisation of the yeast Pichia membranifaciens and its possible use in the biological control of Botrytis cinerea, causing the grey mould disea…
2001
Pichia membranifaciens strain FY-101, isolated from grape skins, was found to be antagonistic to Botrytis cinerea, the causal organism of the grey mould disease of the grapevine. When grown together on solid as well as liquid media, the yeast brings about the inhibition of this parasitic fungus, coagulation and leakage of its cytoplasm, and suppression of its ability to produce the characteristic grey mould symptoms on the grapevine plantlets. In vitro experiments confirm that this yeast can be used as a biological control organism against B. cinerea. An account of the molecular characterisation of P. membranifaciens (complete sequence of the ITS region of its ribosomal DNA, GenBank accessi…
The hemoglobin genes of Drosophila
2006
We recently reported the unprecedented occurrence of a hemoglobin gene (glob1) in the fruitfly Drosophila melanogaster. Here we investigate the structure and evolution of the glob1 gene in other Drosophila species. We cloned and sequenced glob1 genes and cDNA from D. pseudoobscura and D. virilis, and identified the glob1 gene sequences of D. simulans, D. yakuba, D. erecta, D. ananassae, D. mojavensis and D. grimshawi in the databases. Gene structure (introns in helix positions D7.0 and G7.0), gene synteny and sequence of glob1 are highly conserved, with high ds/dn ratios indicating strong purifying selection. The data suggest an important role of the glob1 protein in Drosophila, which may b…
Phylogenetic relationships of the family Campulidae (Trematoda) based on 18S rRNA sequences
1998
Traditionally, the family Campulidae has been associated either with the family Fasciolidae, parasites of ruminants, or the Acanthocolpidae, parasites of fishes, based on morphological similarities. Since morphology does not seem to resolve clearly the problem of the relationships of campulids, we have used the sequences of the 18S rRNA gene of the campulids Zalophotrema hepaticum, Campula oblonga and Nasitrema globicephalae, the fasciolid Fasciola hepatica, the acanthocolpid Stephanostomum baccatum and the outgroup Schistosoma mansoni to infer a phylogeny. Maximum parsimony and neighbour-joining methods were applied. Both methods indicated that campulids are closer to acanthocolpids than f…
Evidence for Natural Horizontal Transfer of the pcpB Gene in the Evolution of Polychlorophenol-Degrading Sphingomonads
2002
ABSTRACT The chlorophenol degradation pathway in Sphingobium chlorophenolicum is initiated by the pcpB gene product, pentachlorophenol-4-monooxygenase. The distribution of the gene was studied in a phylogenetically diverse group of polychlorophenol-degrading bacteria isolated from contaminated groundwater in Kärkölä, Finland. All the sphingomonads isolated were shown to share pcpB gene homologs with 98.9 to 100% sequence identity. The gene product was expressed when the strains were induced by 2,3,4,6-tetrachlorophenol. A comparative analysis of the 16S rDNA and pcpB gene trees suggested that a recent horizontal transfer of the pcpB gene was involved in the evolution of the catabolic pat…
Evolution of arginine deiminase (ADI) pathway genes
2002
We have analyzed the evolution of the three genes encoding structural enzymes of the arginine deiminase (ADI) pathway, arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) in a wide range of organisms, including Archaea, Bacteria, and Eukarya. This catabolic route was probably present in the last common ancestor to all the domains of life. The results obtained indicate that these genes have undergone a complex evolutionary history, including horizontal transfer events, duplications, and losses. Therefore, these genes are not adequate to infer organismal relationships at deep branching levels, but they provide an insight into how catabolic genes evolved and …
Calculating the Homology of the Image
2020
We introduce the alternating homology of a space with a symmetric group action, and give a new construction of the image computing spectral sequence (ICSS), which computes the homology of the image of a finite map from the alternating homology of its multiple point spaces. We illustrate and motivate the ICSS with simple examples.
Population genetics of cucumber mosaic virus infecting medicinal, aromatic and ornamental plants from northern Italy
2012
An epidemiological survey carried at the Herb Garden of Casola Valsenio (Emilia Romagna region; Northern Italy) from 2006 to 2009 resulted in finding Cucumber mosaic virus (CMV) as the infectious agent of several ornamental, medicinal and aromatic plants. All CMV-infected plant species showed leaf symptoms followed, in some cases, by flower colour-breaking and stunting. Genetic analysis consisted in the characterization of movement protein gene of each CMV-isolate by single strand polymorphism analysis and sequencing. Phylogenetic trees identified only two isolates as member of subgroup II, while all other isolates were part of subgroup IA. This survey confirms an unexpected increment of CM…
On Fibrations Between Internal Groupoids and Their Normalizations
2018
We characterize fibrations and $$*$$ -fibrations in the 2-category of internal groupoids in terms of the comparison functor from certain pullbacks to the corresponding strong homotopy pullbacks. As an application, we deduce the internal version of the Brown exact sequence for $$*$$ -fibrations from the internal version of the Gabriel–Zisman exact sequence. We also analyse fibrations and $$*$$ -fibrations in the category of arrows and study when the normalization functor preserves and reflects them. This analysis allows us to give a characterization of protomodular categories using strong homotopy kernels and a generalization of the Snake Lemma.
A crucial role of adamantanoid Cu(II) complexes in the redox systems: CuCl–diallylsulfoxide–O2 and CuCl2–diallylsulfide–O2
2014
Abstract The hypothetically reversible [Cu(I)(diallylsulfoxide)] ↔ O 2 [Cu(II)(diallylsulfide)] system was examined by FTIR spectroscopy and X-ray diffraction. It is stated that the Cu4OCl6 body centered adamantanoid cages, appearing at both the substrate and product sites, act as a template to promote the oxidation of diallylsulfide to diallylsulfoxide or Cu(I) to Cu(II), thus making the reaction irreversible. Each of these two adamantanoid cores possesses a different point symmetry as well as self assembly mode to form two polymorphs of the [Cu4OCl6(diallylsulfoxide)4] complex. Their polymorphic relationships based on the symmetry homology S4 ← Td → C3, as well as the distortion in the Cu…
Rat olfactory bulb and epithelium UDP-glucuronosyltransferase 2A1 (UGT2A1) expression: in situ mRNA localization and quantitative analysis.
2001
UDP-glucuronosyltransferases (UGTs) form a multigenic family of enzymes involved in the biotransformation and elimination of numerous endo- and xenobiotic compounds. Beside the diverse UGT isoforms present in the liver as well as in other tissues, the UGT2A1 isoform, also called olfactory UGT, was initially thought to be expressed in the nasal epithelium only. In this work, we demonstrate the UGT2A1 mRNA expression in the olfactory bulb, using in situ hybridization and quantitative reverse transcription-polymerase chain reaction (RT-PCR) techniques. Within the epithelium, UGT2A1 mRNA is mainly found in the sustentacular cells and to a lesser extent in Bowman's gland cells. Moreover, in situ…