Mitochondrial DNA Damage Following Isolated Muscle Exercise: A Preliminary Investigation Into HO-1 Gene Expression

PURPOSE: This preliminary investigation was designed to test the hypothesis that high intensity single-leg exercise can cause extensive cell DNA damage, which subsequently may affect the expression of the HO-1 gene. METHODS: Six (n=6) apparently healthy male participants (age 27 + 7 yrs, stature 174 + 12 cm, body mass 79 + 4 kg and BMI 24 + 4 kg/m2) completed 100 isolated and continuous maximal concentric contractions (minimum force = 200 N, speed of contraction = 60°/sec) of the rectus femoris muscle. Using a spring-loaded and reusable Magnum biopsy gun with a 16-gauge core disposable biopsy needle, skeletal muscle micro biopsy tissue samples were extracted at rest and following exercise. mRNA gene expression was determined via two-step quantitative real-time PCR using GAPDH as a reference gene. RESULTS: The average muscle force production was 379 + 179 N. High intensity exercise increased mitochondrial 8-OHdG concentration (P < 0.05 vs. rest) with a concomitant decrease in total antioxidant capacity (P < 0.05 vs. rest). Exercise also increased protein oxidation as quantified by protein carbonyl concentration (P < 0.05 vs. rest). HO-1 expression increased (> 2-fold change vs. rest) following exercise, and it is postulated that this change was not significant due to low subject numbers (P > 0.05). CONCLUSION: These preliminary findings tentatively suggest that maximal concentric muscle contractions can cause intracellular DNA damage with no apparent disruption to the expression of the antioxidant stress protein HO-1. Moreover, it is likely that cell oxidant stress is required to activate the signal transduction cascade related to the expression of HO-1. A large-scale study incorporating a greater subject number is warranted to fully elucidate this relationship.

Gene Mapping of 18S and 5S rDNA Genes in the Karyotype of the Three-Spot Gourami Trichogaster trichopterus (Perciformes, Osphronemidae)

Ornamental fish culture is important as an economic activity and for biodiversity conservation as well. The species of the genus Trichogaster (Perciformes, Osphronemidae), popularly known as three-spot gourami, are among the several commercial species raised around the world. In the present work, eight specimens of Thrichogaster trichopterus from aquarium trade facilities were analyzed. The karyotype was composed of 23 pairs of subtelo/acrocentric chromosomes. Fluorescent in situ hybridization allowed identifying the 18S ribosomal gene at telomeric region on long arms of the largest acrocentric pair. On the other hand, the 5S rRNA gene is located at a proximal region on a pair of medium-sized chromosomes. Such information is extremely useful in face of the risks of introduction and the development of ornamental fish trade, once many fish species can be identified only by genetic studies.

Chromosome polymorphism in Astyanax fasciatus (Teleostei, Characidae). 2-Chromosomal location of a satellite DNA

Studies about composition of repetitive sequences and their chromosomal location have been helpful to evolutionary studies in many distinct organisms. In order to keep on assessing the possible relationships among different cytotypes of Astyanax fasciatus (Teleostei, Characiformes) in the Mogi-Guacu River (Sao Paulo State, Brazil), C-banding, chromomycin A 3 staining, and fluorescent in situ hybridization with a repetitive DNA sequence (As51) isolated from Astyanax scabripinnis were performed in the present work. The constitutive heterochromatin was distributed in terminal regions on long arms of submetacentric, subtelocentric, and acrocentric chromosomes and in the terminal region on short arms of a pair of submetacentric chromosomes in both standard cytotypes. This latter heterochromatic site was also GC-rich, as revealed by chromomycin A(3) staining, corresponding to the nucleolar organizer region (NOR), as shown by previous studies. The sites of the satellite As51 DNA were located in terminal regions on long arms of several chromosomes. Some variant karyotypic forms, which diverge from the two standard cytotypes, also presented distinctive chromosomes carrying As51 satellite DNA. It is possible that the standard 2n = 46 cytotype represents an invader population in the Mogi-Guacu River able to interbreed with the resident standard 2n = 48 cytotype. Therefore, the variant karyotypes would be related to a possible viable offspring, where complementary chromosomal rearrangements could favor new locations of the satellite DNA analyzed. Copyright (C) 2008 S. Karger AG, Basel

Comparative chromosome mapping of 5S rDNA and 5SHindIII repetitive sequences in Erythrinidae fishes (Characiformes) with emphasis on the Hoplias malabaricus 'species complex'

Chromosomal localization of 5S rDNA and 5SHindIII repetitive sequences was carried out in several representatives of the Erythrinidae family, namely in karyomorphs A, D, and F of Hoplias malabaricus, and in H. lacerdae, Hoplerythrinusunitaeniatus and Erythrinus erythrinus. The 5S rDNA mapped interstitially in two chromosome pairs in karyomorph A and in one chromosome pair in karyomorphs D and F and in H. lacerdae. The 5SHindIII repetitive DNA mapped to the centromeric region of several chromosomes (18 to 22 chromosomes) with variations related to the different karyomorphs of H. malabaricus. on the other hand, no signal was detected in the chromosomes of H. lacerdae, H. unitaeniatus and E. erythrinus, suggesting that the 5SHindIII-DNA sequences have originated or were lost after the divergence of H. malabaricus from the other erythrinid species. The chromosome distribution of 5S rDNA and 5SHindIII-DNA sequences contributes to a better understanding of the mechanisms of karyotype differentiation among the Erythrinidae members.Copyright (c) 2007 S. Karger AG, Basel.

Discrimination of Shark species by simple PCR of 5S rDNA repeats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative Cytogenetic Analysis of the Genus Symphysodon (Discus Fishes, Cichlidae): Chromosomal Characteristics of Retrotransposons and Minor Ribosomal DNA

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cytogenetic Mapping of 5S and 18S rRNAs and H3 Histone Genes in 4 Ancient Proscopiidae Grasshopper Species: Contribution to Understanding the Evolutionary Dynamics of Multigene Families

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

B chromosome in the beetle Coprophanaeus cyanescens (Scarabaeidae): emphasis in the organization of repetitive DNA sequences

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Organization of 5S rDNA in species of the fish Leporinus: two different genomic locations are characterized by distinct nontranscribed spacers

To address understanding the organization of the 5S rRNA multigene family in the fish genome, the nucleotide sequence and organization array of 5S rDNA were investigated in the genus Leporinus, a representative freshwater fish group of South American fauna. PCR, subgenomic library screening, genomic blotting, fluorescence in situ hybridization, and DNA sequencing were employed in this study. Two arrays of 5S rDNA were identified for all species investigated, one consisting of monomeric repeat units of around 200 bp and another one with monomers of 900 bp. These 5S rDNA arrays were characterized by distinct NTS sequences (designated NTS-I and NTS-II for the 200- and 900-bp monomers, respectively); however, their coding sequences were nearly identical. The 5S rRNA genes were clustered in two chromosome loci, a major one corresponding to the NTS-I sites and a minor one corresponding to the NTS-II sites. The NTS-I sequence was variable among Leporinus spp., whereas the NTS-II was conserved among them and even in the related genus Schizodon. The distinct 5S rDNA arrays might characterize two 5S rRNA gene subfamilies that have been evolving independently in the genome.

Distribution of 45S and 5S rDNA sites in 23 species of Eleocharis (Cyperaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nucleotide sequence of 5S rDNA and localization of the ribosomal RNA genes to metaphase chromosomes of the Tilapiine cichlid fish, Oreochromis niloticus

In this study, we report the cloning and nucleotide sequence of PCR-generated 5S rDNA from the Tilapiine cichlid fish, Oreochromis niloticus. Two types of 5S rDNA were detected that differed by insertions and/or deletions and base substitutions within the non-transcribed spacer (NTS). Two 5S rDNA loci were observed by fluorescent in situ hybridization (FISH) in metaphase spreads of tilapia chromosomes. FISH using an 18S rDNA probe and silver nitrate sequential staining of 5S-FISH slides showed three 18S rDNA loci that are not syntenic to the 5S rDNA loci.

Evolutionary dynamics of 5S rDNA location in acridid grasshoppers and its relationship with H3 histone gene and 45S rDNA location

We analyze the chromosomal location of 5S rDNA clusters in 29 species of grasshoppers belonging to the family Acrididae. There was extensive variation among species for the number and location of 5S rDNA sites. Out of 148 sites detected, 75% were proximally located, 21.6% were interstitial, and only 3.4% were distal. The number of 5S rDNA sites per species varied from a single chromosome pair (in six species) to all chromosome pairs (in five species), with a range of intermediate situations. Thirteen chromosomes from eight species carried two 5S rDNA clusters. At intraspecific level, differences among populations were detected in Eyprepocnemis plorans, and some heteromorphisms have also been observed in some species. Double FISH for 5S rDNA and H3 histone gene DNA, performed on 17 of these 29 species, revealed that both markers are sometimes placed in a same chromosome but at different location, whereas they appeared to co-localize in five species (Calliptamus barbarus, Heteracris adpersa, Aiolopus strepens, Oedipoda charpentieri and O. coerulescens). Double fiber-FISH in A. strepens and O. coerulescens showed that the two DNAs are closely interspersed with variable relative amounts of both classes of DNA. Finally, no correlation was observed between the number of 5S and 45S rDNA clusters in 23 species where this information was available. These results are discussed in the light of possible mechanisms of spread that led to the extensive variation in the number of clusters observed for both rDNA types in acridid grasshoppers. © 2011 Springer Science+Business Media B.V.

Chromosomal evolution of neotropical cichlids: The role of repetitive DNA sequences in the organization and structure of karyotype

Cichlids are important in the aquaculture and ornamental fish trade and are considered models for evolutionary biology. However, most studies of cichlids have investigated African species, and the South American cichlids remain poorly characterized. Studies in neotropical regions have focused almost exclusively on classical cytogenetic approaches without investigating physical chromosomal mapping of specific sequences. The aim of the present study is to investigate the genomic organization of species belonging to different tribes of the subfamily Cichlinae (Cichla monoculus, Astronotus ocellatus, Geophagus proximus, Acaronia nassa, Bujurquina peregrinabunda, Hoplarchus psittacus, Hypselecara coryphaenoides, Hypselecara temporalis, Caquetaia spectabilis, Uaru amphiacanthoides, Pterophyllum leopoldi, Pterophyllum scalare, and Symphysodon discus) and reexamine the karyotypic evolutionary patterns proposed for this group. Variations in some cytogenetic markers were observed, although no trends were found in terms of the increase, decrease, or maintenance of the basal diploid chromosome number 2n = 48 in the tribes. Several species were observed to have 18S rDNA genetic duplications, as well as multiple rDNA loci. In most of the taxa analyzed, the 5S rDNA was located in the interstitial region of a pair of homologous chromosomes, although variations from this pattern were observed. Interstitial telomere sites were also observed and appear to be involved in chromosomal rearrangement events and the accumulation of repeat-rich satellite DNA sequences. Our data demonstrated the karyotypic diversity that exists among neotropical cichlids, suggesting that most of this diversity is due to the repetitive sequences present in heterochromatic regions and that repeat sequences have greatly influenced the karyotypic evolution of these fishes. © 2012 Springer Science+Business Media B.V.

Mapping five repetitive DNA classes in sympatric species of Hypostomus (Teleostei: Siluriformes: Loricariidae): analysis of chromosomal variability

Fish belonging to the genus Hypostomus are known for exhibiting a striking diversity in its karyotype structure, however the knowledge concerning the distribution patterns of heterochromatin and location of repetitive DNA sequences in the karyotypes is still limited. Aiming a better understanding of the chromosomal organization in this group, we analyzed three sympatric species of Hypostomus collected in the Hortelã stream, a component of the Paranapanema River basin, Botucatu/SP/Brazil. The analyses involved the cytogenetic characterization and chromosomal mapping of repetitive sequences and intra/interspecific comparisons using sequences of the cytochrome C oxidase subunit I. The results revealed that H. ancistroides presents a karyotype with 2n = 68 chromosomes, H. strigaticeps 2n = 72 chromosomes, and H. nigromaculatus 2n = 76 chromosomes. In addition to differences found in the diploid number, it was also observed variations in karyotypic formulae, amount of constitutive heterochromatin, and location of nucleolus organizer regions. The cytogenetic mapping of 5S and 18S rDNA, as well as of the H3 histone gene, disclosed a differential dispersion process among the three species. In some cases the Rex1 transposable element showed to be co-located with 5S rDNA sites. The molecular analyses support the cytogenetic data and represent an additional tool for the characterization of the analyzed species. The results evidenced that chromosomal variations are not restricted to differences in diploid number or karyotypic macrostructure in the genus Hypostomus, indicating that events such as transposition of heterochromatin and rDNA segments may participate in the differentiation process occurred in these species. © 2013 Springer Science+Business Media Dordrecht.