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Differentiation of Melipona quadrifasciata L. (Hymenoptera, Apidae, Meliponini) subspecies using cytochrome b PCR-RFLP patterns

SOUZA, Rogério O.; MORETTO, Geraldo; ARIAS, Maria C.; DEL LAMA, Marco A.
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.94%
Melipona quadrifasciata quadrifasciata and M. quadrifasciata anthidioides are subspecies of M. quadrifasciata, a stingless bee species common in coastal Brazil. These subspecies are discriminated by the yellow stripe pattern of the abdominal tergites. We found Vsp I restriction patterns in the cytochrome b region closely associated to each subspecies in 155 M. quadrifasciata colonies of different geographical origin. This mitochondrial DNA molecular marker facilitates diagnosis of M. quadrifasciata subspecies matrilines and can be used to establish their natural distribution and identify hybrid colonies.

Cytochrome-b variation in Apis mellifera samples and its association with COI-COII patterns

FERREIRA, Katia M.; SILVA, Otavio Lino e; ARIAS, Maria C.; LAMA, Marco A. Del
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.99%
Five Mbo I (Mbo-A, Mbo-M, Mbo-C(1), Mbo-C(2) and Mbo-C(3)) and Hinf I (Hinf-1 to Hinf-5) patterns were observed in Apis mellifera samples after restriction of a 485 bp fragment of the mitochondrial cytochrome-b (cyt-b) gene. Associating the cyt-b Restriction fragment length polymorphism (RFLP) pattern of each sample to its respective previously established COI-COII (Dra I sites) pattern, five restriction patterns (Mbo-C(1), Mbo-C(2), Mbo-C(3), Hinf-1 and Hinf-4) were observed in samples of maternal origin associated to the evolutionary branch C. No deletions or insertions were observed and the nucleotide substitution rate was estimated at 5.4%. Higher nucleotide diversity was observed among the branch C-haplotypes when compared with A and M lineages. Further studies are needed to confirm if the cyt-b + COI-COII haplotypes help to assign certain phylogeographic patterns to the branch C and to clarify phylogenetic relationships among A. mellifera subspecies.; Fapesp[03/06342-9]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new genotype of Trypanosoma cruzi associated with bats evidenced by phylogenetic analyses using SSU rDNA, cytochrome b and Histone H2B genes and genotyping based on ITS1 rDNA

MARCILI, A.; LIMA, L.; CAVAZZANA, M. Jr.; JUNQUEIRA, A. C. V.; VELUDO, H. H.; SILVA, F. Maia Da; CAMPANER, M.; PAIVA, F.; NUNES, V. L. B.; TEIXEIRA, M. M. G.
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
75.96%
We characterized 15 Trypanosoma cruzi isolates from bats captured in the Amazon, Central and Southeast Brazilian regions. Phylogenetic relationships among T. cruzi lineages using SSU rDNA, cytochrome b, and Histone H2B genes positioned all Amazonian isolates into T. cruzi I (TCI). However, bat isolates from the other regions, which had been genotyped as T. cruzi II (TC II) by the traditional genotyping method based on mini-exon gene employed in this study, Were not nested within any of the previously defined TCII sublineages, constituting a new genotype designated as TCbat. Phylogenetic analyses demonstrated that TCbat indeed belongs to T. cruzi and not to other closely related bat trypanosomes of the subgenus Schizotrypanum, and that although separated by large genetic distances TO-tat is closest to lineage TCI. A genotyping method targeting ITS1 rDNA distinguished TCbat from established T. cruzi lineages, and from other Schizotrypanum species. In experimentally infected mice, TCbat lacked virulence and yielded loss parasitaemias. Isolates of TCbat presented distinctive morphological features and behaviour in triatomines. To date, TCbat genotype wall found only in bats from anthropic environments of Central and Southeast Brazil. Our findings indicate that the complexity of T. cruzi is larger than currently known...

SYSTEMATIC RELATIONSHIPS WITHIN CHIRODERMA (CHIROPTERA, PHYLLOSTOMIDAE) BASED ON CYTOCHROME-B SEQUENCE VARIATION

Baker, R. J.; Taddei, V. A.; Hudgeons, J. L.; Vandenbussche, R. A.
Fonte: Alliance Communications Group Division Allen Press Publicador: Alliance Communications Group Division Allen Press
Tipo: Artigo de Revista Científica Formato: 321-327
ENG
Relevância na Pesquisa
65.94%
The Neotropical bat genus Chiroderma consists of five recognized species. This study uses DNA-sequence variation of the mitochondrial cytochrome b gene to infer the phylogenetic relationships within Chiroderma. Phylogenetic relationships deduced from these data by parsimony analyses resulted in the discovery of a single most-parsimonious tree with C. salvini diverging basal to the other four species of Chiroderma and sister-group relationships of C. villosum with C. improvisum and C. trinitatum with C. doriae. This is a relatively young group of species with approximate times of divergence ranging from 1.6 million years before present (mya) for the divergence of C. doriae from C. trinitatum to 4.6 mya for the divergence of C. salvini from the other four species of Chiroderma.

Identification of blood meal sources of Lutzomyia longipalpis using polymerase chain reaction-restriction fragment length polymorphism analysis of the cytochrome B gene

Soares, Vítor Yamashiro Rocha; Silva, Jailthon Carlos Da; Silva, Kleverton Ribeiro Da; Cruz, Maria Do Socorro Pires E; Santos, Marcos Pérsio Dantas; Ribolla, Paulo Eduardo Martins; Alonso, Diego Peres; Coelho, Luiz Felipe Leomil; Costa, Dorcas Lamounier
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: 379-383
ENG
Relevância na Pesquisa
65.94%
An analysis of the dietary content of haematophagous insects can provide important information about the transmission networks of certain zoonoses. The present study evaluated the potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mitochondrial cytochrome B (cytb) gene to differentiate between vertebrate species that were identified as possible sources of sandfly meals. The complete cytb gene sequences of 11 vertebrate species available in the National Center for Biotechnology Information database were digested with Aci I, Alu I, Hae III and Rsa I restriction enzymes in silico using Restriction Mapper software. The cytb gene fragment (358 bp) was amplified from tissue samples of vertebrate species and the dietary contents of sandflies and digested with restriction enzymes. Vertebrate species presented a restriction fragment profile that differed from that of other species, with the exception of Canis familiaris and Cerdocyon thous. The 358 bp fragment was identified in 76 sandflies. Of these, 10 were evaluated using the restriction enzymes and the food sources were predicted for four: Homo sapiens (1), Bos taurus (1) and Equus caballus (2). Thus, the PCR-RFLP technique could be a potential method for identifying the food sources of arthropods. However...

Molecular characterization of Portuguese populations of the pinewood nematode Bursaphelenchus xylophilus using cytochrome b and cellulase genes

Valadas, Vera; Laranjo, Marta; Mota, Manuel; Oliveira, Solange
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.96%
Bursaphelenchus xylophilus is the causal agent of pine wilt disease and a worldwide pest with high economic impact. Since its first diagnosis in Portugal in 1999, it has been subjected to quarantine measures with impact on forest health and ecosystem stability, significantly affecting international trade of wood products. The disease was detected in the north and centre of continental Portugal and, since 2008, the whole country has been considered an affected area. Recently, it was detected in Madeira Island. In order to avoid new outbreaks, it has become of major importance to understand the patterns of spread, introduction points and to characterize the new populations from continental Portugal and Madeira Island. Mitochondrial cytochrome b (cytb) and parasitic cellulase gene sequences were used to evaluate the genetic relationships among isolates that could indicate possible origins of the new outbreaks. Portuguese isolates were compared with isolates from USA, China, Japan and South Korea, in order to investigate possible infection pathways and disease spread patterns in Portugal. Phylogenetic trees based on both genes show that Portuguese isolates group with Asian isolates. Isolates from USA are in a separate position in both gene trees. However...

Genetic diversity of Triatoma infestans (Hemiptera: Reduviidae) in Chuquisaca, Bolivia based on the mitochondrial cytochrome b gene

Giordano,Rosanna; Cortez,Juan Carlos Pizarro; Paulk,Stephanie; Stevens,Lori
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2005 EN
Relevância na Pesquisa
65.94%
Partial cytochrome b DNA sequences for 62 Triatoma infestans were analyzed to determine the degree of genetic variation present in populations of this insect in the northwest region of Chuquisaca, Bolivia. A total of seven haplotypes were detected in the localities sampled. The phylogenetic relationship and population genetic structure of the haplotypes found in this region, indicate that there is greater variation in this relatively small region of Bolivia than what has been previously reported by studies using the same gene fragment, for more distant geographic areas of this country. In addition, a comparison of rural and peri-urban localities, indicate that there is no difference in the genetic variation of T. infestans between these two environments.

Identification of blood meal sources of Lutzomyia longipalpis using polymerase chain reaction-restriction fragment length polymorphism analysis of the cytochrome B gene

Soares,Vítor Yamashiro Rocha; Silva,Jailthon Carlos da; Silva,Kleverton Ribeiro da; Cruz,Maria do Socorro Pires e; Santos,Marcos Pérsio Dantas; Ribolla,Paulo Eduardo Martins; Alonso,Diego Peres; Coelho,Luiz Felipe Leomil; Costa,Dorcas Lamounier; Costa,C
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2014 EN
Relevância na Pesquisa
65.94%
An analysis of the dietary content of haematophagous insects can provide important information about the transmission networks of certain zoonoses. The present study evaluated the potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the mitochondrial cytochrome B (cytb) gene to differentiate between vertebrate species that were identified as possible sources of sandfly meals. The complete cytb gene sequences of 11 vertebrate species available in the National Center for Biotechnology Information database were digested with Aci I, Alu I, Hae III and Rsa I restriction enzymes in silico using Restriction Mapper software. The cytb gene fragment (358 bp) was amplified from tissue samples of vertebrate species and the dietary contents of sandflies and digested with restriction enzymes. Vertebrate species presented a restriction fragment profile that differed from that of other species, with the exception of Canis familiaris and Cerdocyon thous. The 358 bp fragment was identified in 76 sandflies. Of these, 10 were evaluated using the restriction enzymes and the food sources were predicted for four: Homo sapiens (1), Bos taurus (1) and Equus caballus (2). Thus, the PCR-RFLP technique could be a potential method for identifying the food sources of arthropods. However...

Differentiation of Melipona quadrifasciata L. (Hymenoptera, Apidae, Meliponini) subspecies using cytochrome b PCR-RFLP patterns

Souza,Rogério O.; Moretto,Geraldo; Arias,Maria C.; Del Lama,Marco A.
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
65.94%
Melipona quadrifasciata quadrifasciata and M. quadrifasciata anthidioides are subspecies of M. quadrifasciata, a stingless bee species common in coastal Brazil. These subspecies are discriminated by the yellow stripe pattern of the abdominal tergites. We found Vsp I restriction patterns in the cytochrome b region closely associated to each subspecies in 155 M. quadrifasciata colonies of different geographical origin. This mitochondrial DNA molecular marker facilitates diagnosis of M. quadrifasciata subspecies matrilines and can be used to establish their natural distribution and identify hybrid colonies.

The cytochrome b-558 molecules involved in the fibroblast and polymorphonuclear leucocyte superoxide-generating NADPH oxidase systems are structurally and genetically distinct.

Meier, B; Jesaitis, A J; Emmendörffer, A; Roesler, J; Quinn, M T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/01/1993 EN
Relevância na Pesquisa
56.18%
We have demonstrated that human fibroblasts can release O2-. radicals by an NADPH oxidase system that appears to be functionally similar to the phagocytic system. Further analysis of these systems, however, with respect to the low-potential b-type cytochromes involved suggests that these two O2-.-generating systems are not structurally identical. Immunoblot analysis of fibroblast membranes with six different antibodies directed against both subunits of human neutrophil cytochrome b-558 indicated that the b-type cytochrome molecules involved in these systems were not identical. None of these anti-(neutrophil cytochrome b) antibodies recognized a similar cytochrome in fibroblast membranes, suggesting that the two cytochrome species are immunologically distinct. In addition, fibroblasts obtained from a patient suffering from X-linked chronic granulomatous disease (CGD) had a normal cytochrome b-558 content compared with control fibroblast membranes, whereas the cytochrome b-558 concentration in polymorphonuclear leucocytes (PMNs) from this patient was decreased to 10% of that found in PMNs from healthy controls. Likewise, the stimulated O2-. release in PMNs from this patient was less than 10% of that in control PMNs, whereas the fibroblasts showed stimulated O2-.-release rates that were indistinguishable from those of fibroblasts obtained from healthy persons. Since the genetic mutation responsible for this type of CGD results in the absence of cytochrome b-558 in PMNs...

Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes.

Segal, A W; West, I; Wientjes, F; Nugent, J H; Chavan, A J; Haley, B; Garcia, R C; Rosen, H; Scrace, G
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/06/1992 EN
Relevância na Pesquisa
56.18%
The NADPH oxidase of phagocytic cells is important for the efficient killing and digestion of ingested microbes. A very unusual low-potential cytochrome b (b-245) is the only redox molecule to have been identified in this system. The FAD-containing flavoprotein that binds NADPH and transfers electrons to the cytochrome has eluded identification for three decades. We show here that the haem/FAD ratio in the membranes does not change significantly on activation of this oxidase, indicating that the FAD is present in the membranes from the outset and not recruited from the cytosol. The FAD content of membranes from cells of patients with X-linked chronic granulomatous disease (CGD) lacking the cytochrome b was roughly one-quarter of that in normal subjects and in autosomal recessive CGD patients lacking the cytosolic protein p47-phox. Similar low amounts of FAD were present in uninduced promyelocytic (HL60) cells, suggesting that the low amount of FAD in cells from X-CGD patients was probably unrelated to this oxidase system. Cytochrome b-245 appears to bind both the haem and FAD, in a molar ratio of 2:1. The e.p.r. signal of the purified cytochrome was weak and had an asymmetric g(z) peak at g = 3.31. The purified cytochrome could be partially reflavinated (about 20%) in the presence of lipid. Amino acid sequence homology was detected between the beta-subunit of this cytochrome b and the ferredoxin-NADP+ reductase (FNR) family of reductases in the putative NADPH- and FAD-binding sites. 32P-labelled 2-azido-NADP was used as a photoaffinity label for the NADPH-binding site. Labelling that was competed off with NADP was observed in the region of the beta-subunit of the cytochrome. No labelling was seen in this region in X-CGD in three subjects in whom this cytochrome was missing and in a third in whom it was present but bore a Pro-His transposition in the putative NADPH-binding site. These studies indicate that cytochrome b-245 is a flavocytochrome...

Diversity-Oriented Synthesis Probe Targets Plasmodium falciparum Cytochrome b Ubiquinone Reduction Site and Synergizes With Oxidation Site Inhibitors

Lukens, Amanda K.; Heidebrecht, Richard W.; Mulrooney, Carol; Beaudoin, Jennifer A.; Comer, Eamon; Duvall, Jeremy R.; Fitzgerald, Mark E.; Masi, Daniela; Galinsky, Kevin; Scherer, Christina A.; Palmer, Michelle; Munoz, Benito; Foley, Michael; Schreiber, S
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.07%
Background. The emergence and spread of drug resistance to current antimalarial therapies remains a pressing concern, escalating the need for compounds that demonstrate novel modes of action. Diversity-Oriented Synthesis (DOS) libraries bridge the gap between conventional small molecule and natural product libraries, allowing the interrogation of more diverse chemical space in efforts to identify probes of novel parasite pathways. Methods. We screened and optimized a probe from a DOS library using whole-cell phenotypic assays. Resistance selection and whole-genome sequencing approaches were employed to identify the cellular target of the compounds. Results. We identified a novel macrocyclic inhibitor of Plasmodium falciparum with nanomolar potency and identified the reduction site of cytochrome b as its cellular target. Combination experiments with reduction and oxidation site inhibitors showed synergistic inhibition of the parasite. Conclusions. The cytochrome b oxidation center is a validated antimalarial target. We show that the reduction site of cytochrome b is also a druggable target. Our results demonstrating a synergistic relationship between oxidation and reduction site inhibitors suggests a future strategy for new combination therapies in the treatment of malaria.

Molecular phylogenetics of Puffinus shearwaters: preliminary evidence from mitochondrial cytochrome b gene sequences

Austin, J.
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
Publicado em //1996 EN
Relevância na Pesquisa
65.94%
Puffinus shearwaters (Family Procellariidae) are a diverse genus of pelagic seabirds or petrels with a worldwide distribution. Five subgroups of species have been recognized on the basis of osteological and external morphological characters. However, phylogenetic relationships among extant taxa are poorly understood, and evolutionary scenarios to explain the current overlapping distribution of the species subgroups are speculative. Phylogenetic analyses of partial mitochondrial cytochrome b gene sequences were used to examine the relationships among 19 species and subspecies of Puffinus shearwaters. In general, the molecular data support previous morphologically based phylogenetic hypotheses. However, the subgroup Neonectris appears to be polyphyletic with Puffinus nativitatis more closely related to species in the subgroup Puffinus. In addition the molecular data revealed a phylogenetic split between the Puffinus subgroup, with a worldwide distribution, and the remaining four subgroups which have an essentially southern hemisphere distribution. This suggests an evolutionary history in which the Puffinus ancestor was split between two geographic regions, from which dispersal and vicariant events resulted in the evolution and distribution of extant taxa.; Jeremy J. Austin

ENERGY-COUPLING MECHANISMS IN MITOCHONDRIA: KINETIC, SPECTROSCOPIC, AND THERMODYNAMIC PROPERTIES OF AN ENERGY-TRANSDUCING FORM OF CYTOCHROME b*

Chance, B.; Wilson, D. F.; Dutton, P. L.; Erecińska, M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1970 EN
Relevância na Pesquisa
56.11%
The primary event of coupled electron transfer at phosphorylation site II is identified with a modification in one of the two chemically distinct forms of cytochrome b, designated as the energy-transducing cytochrome bT. This modification is expressed through a change in the redox midpoint potential and by an increase in its reaction half time with cytochrome c1. In pigeon heart mitochondria cytochrome bT exhibits an absorption maximum at 564 nm and on this basis, it can be distinguished from Keilin's cytochrome b which exhibits an absorption maximum at 560 nm and serves as an electron carrier on the substrate side of cytochrome bT. Kinetic capability of cytochrome bT is evidenced by its rapid electron transfer and energization time of less than 200 msec, its thermodynamic capability—by a 280 mV potential span suitable for providing one of the two electron transfer reactions required in ATP formation. Two secondary events of coupled electron flow may be identified with a charge separation across the lipid structure of the permeability barrier and a change in water structure; both events result in an increased 1-anilino-8-naphthalene-sulfonic acid (ANS) response to the altered environment.

Three functionally different cytochrome b redox centres in pigeon heart mitochondria.

Rasmussen, U F; Rasmussen, H N; Jørgensen, B M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/02/1982 EN
Relevância na Pesquisa
56.16%
Three functionally different cytochrome b redox centres, apparently of high metabolic activity, were detected in intact pigeon heart mitochondria; cytochrome b(1), b(m) and b(h), with maxima of absorption at 556.6 (State 5), 560.6, and 564.5 nm, respectively (alpha-bands, 77K). 2. Cytochrome (b(l) was reduced in the presence of either antimycin or HQNO (2-heptyl-4-hydroxyquinoline N-oxide). The absorption maximum was shifted by dithionite, cyanide, NNN'N'-tetramethyl-p-phenylenediamine + ascorbate, HQNO and antimycin. The spectra obtained on simultaneous or successive addition of HQNO and antimycin favoured the assumption of a common binding site for the two inhibitors. 3. Cytochrome b(m) was reduced in the presence of HQNO, but not in the presence of antimycin. No shifts of absorption maximum was observed. 4. Cytochrome b(h) was reduced in the presence of antimycin. HQNO was unable to cause reduction of this cytochrome by endogenous substrates. The absorption maximum was shifted to lower wavelength by organic solvents. It was inseparable from that of cytochrome b(m) in the presence of 0.4% ethanol. 5. The pattern of reduction in the presence of HQNO or antimycin demonstrates the functional difference of the three redox centres and appears incompatible wih a linear respiratory chain.

Trypanosoma cruzi Genotypes of Insect Vectors and Patients with Chagas of Chile Studied by Means of Cytochrome b Gene Sequencing, Minicircle Hybridization, and Nuclear Gene Polymorphisms

Coronado, Ximena; Solari, Aldo; Campos, Ricardo; Ortiz, Sylvia; Arenas, Marco
Fonte: MARY ANN LIEBERT INC Publicador: MARY ANN LIEBERT INC
Tipo: Artículo de revista
EN
Relevância na Pesquisa
65.99%
Fifty-six Trypanosoma cruzi stocks from Chile and neighboring countries and different hosts, humans, and Triatoma infestans and Mepraia sp., vectors of domiciliary and natural environments were characterized by using three molecular markers. These were cytochrome b (Cyt b) gene sequencing, minicircle DNA blotting, and hybridization with five genotype-specific DNA probes and nuclear analysis of 1f8 and gp72 by polymerase chain reaction–restriction fragment length polymorphism. The results with all three molecular markers are concordant, with minor limitations, grouping T. cruzi stocks into four discrete typing units (DTUs) (TcI, TcII, TcV, and TcVI). TcI and TcII stocks were heterogeneous. TcI and TcII stocks were clustered in two main subgroups determined by Cyt b gene sequencing and minicircle hybridization. However, TcV and TcVI stocks were homogeneous and not differentiated by Cyt b gene sequencing or minicircle DNA hybridization. The discriminatory power and limitations of the molecular markers are discussed, as well as the distribution of the four DTUs in the domiciliary and sylvatic transmission cycles of Chile and the limitations of each marker for molecular epidemiological studies performed with T. cruzi stocks rather than the analysis of direct T. cruzi samples from natural hosts.; FONDECYT 1085154 European Community 223034

Estimating the frequency of Asian cytochrome B haplotypes in European standard and Spanish local pig breeds

Clop, Àlex; Amills i Eras, Marcel; Noguera, José Luís; Fernández, Ana; Capote Juan; Ramón, María Misericordia; Kelly, Lucía; Kijas, James M. H.; Andersson, Leif; Sánchez Bonastre, Armando
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2004 ENG
Relevância na Pesquisa
66.07%
Mitochondrial DNA has been widely used to perform phylogenetic studies in different animal species. In pigs, genetic variability at the cytochrome B gene and the D-loop region has been used as a tool to dissect the genetic relationships between different breeds and populations. In this work, we analysed four SNP at the cytochrome B gene to infer the Asian (A1 and A2 haplotypes) or European (E1 and E2 haplotypes) origins of several European standard and local pig breeds. We found a mixture of Asian and European haplotypes in the Canarian Black pig (E1, A1 and A2), German Piétrain (E1, A1 and A2), Belgian Piétrain (E1, A1), Large White (E1 and A1) and Landrace (E1 and A1) breeds. In contrast, the Iberian (Guadyerbas, Ervideira, Caldeira, Campanario, Puebla and Torbiscal strains) and the Majorcan Black pig breeds only displayed the E1 haplotype. Our results show that the introgression of Chinese pig breeds affected most of the major European standard breeds, which harbour Asian haplotypes at diverse frequencies (15–56%). In contrast, isolated local Spanish breeds, such as the Iberian and Majorcan Black pig, only display European cytochrome B haplotypes, a feature that evidences that they were not crossed with other Chinese or European commercial populations. These findings illustrate how geographical confinement spared several local Spanish breeds from the extensive introgression event that took place during the 18th and 19th centuries in Europe.

Conversion of the Escherichia coli Cytochrome b562 to an Archetype Cytochrome b: A Mutant with Bis-Histidine Ligation of Heme Iron

Hay, Sam; Wydrzynski, Thomas
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.14%
A mutant of the Escherichia coli cytochrome b562 has been created in which the heme-ligating methionine (Met) at position 7 has been replaced with a histidine (His) (M7H). This protein is a double mutant that also has the His 63 to asparagine (H63N) mutation, which removes a solvent-exposed His. While the H63N mutation has no measurable effect on the cytochrome, the M7H mutation converts the atypical His/Met heme ligation in cytochrome b 562 to the classic cytochrome b-type bis-His ligation. This mutation has little effect on the Kd of heme binding but significantly reduces the chemical and thermal stability of the mutant cytochrome relative to the wild type (wt). Both proteins have similar absorbance (Abs) and electron paramagnetic resonance (EPR) properties characteristic of 6-coordinate low-spin heme. The Abs spectra of the oxidized and reduced bis-His cytochrome are slightly blue-shifted relative to the wt, and the α Abs band of ferrous M7H mutant is unusually split. The M7H mutation decreases the midpoint potential of the bound heme by 260 mV at pH 7 and considerably alters the pH dependence of the Em, which becomes dominated by a single pKred = 6.8.

Phylogenetic Relationships of Elapid Snakes Based on Cytochrome b mtDNA Sequences

Slowinski, Joseph; Keogh, J Scott
Fonte: Academic Press Publicador: Academic Press
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.02%
Published molecular phylogenetic studies of elapid snakes agree that the marine and Australo-Melanesian forms are collectively monophyletic. Recent studies, however, disagree on the relationships of the African, American, and Asian forms. To resolve the relationships of the African, American, and Asian species to each other and to the marine/Australo-Melanesian clade, we sequenced the entire cytochrome b gene for 28 elapids; 2 additional elapid sequences from GenBank were also included. This sample includes all African, American, and Asian genera (except for the rare African Pseudohaje), as well as a representative sample of marine/Australo-Melanesian genera. The data were analyzed by the methods of maximum-parsimony and maximum-likelihood. Both types of analyses yielded similar trees, from which the following conclusions can be drawn: (1) Homoroselaps falls outside a clade formed by the remaining elapids; (2) the remaining elapids are divisible into two broad sister clades, the marine/Australo-Melanesian species vs the African, American, and Asian species; (3) American coral snakes cluster with Asian coral snakes; and (4) the 'true' cobra genus Naja is probably not monophyletic as the result of excluding such genera as Boulengerina and Paranaja. (C) 2000 Academic Press.

The role of chloroplast electron transport and metabolites in modulating rubisco activity in tobacco. Insights from transgenic plants with reduced amounts of cytochrome b/f complex or glyceraldehyde 3-phosphate dehydrogenase.

Ruuska, S; Andrews, Thomas; Badger, Murray; Price, Graeme (Dean); von Caemmerer, Susanne
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.96%
Leaf metabolites, adenylates, and Rubisco activation were studied in two transgenic tobacco (Nicotiana tabacum L. cv W38) types. Plants with reduced amounts of cytochrome b/f complex (anti-b/f) have impaired electron transport and a low transthylakoid pH