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In previous studies, we characterized a new hormonal pathway involving a mitochondrial T3 receptor (p43) acting as a mitochondrial transcription factor. In in vitro and in vivo studies, we have shown that p43 increases mitochondrial transcription and mitochondrial biogenesis. In addition, p43 overexpression in skeletal muscle stimulates mitochondrial respiration and induces a shift in metabolic and contractile features of muscle fibers which became more oxidative.Here we have studied the influence of p43 overexpression in skeletal muscle of mice during aging. We report that p43 overexpression initially increased mitochondrial mass. However, after the early rise in mitochondrial DNA occurring at 2 months of age in transgenic mice, we observed a progressive decrease of mitochondrial DNA content which became 2-fold lower at 23 months of age relatively to control animals. Moreover, p43 overexpression induced an oxidative stress characterized by a strong increase of lipid peroxidation and protein oxidation in quadriceps muscle, although antioxidant enzyme activities (catalase and superoxide dismutase) were stimulated. In addition, muscle atrophy became detectable at 6 months of age, probably through a stimulation of the ubiquitin proteasome pathway via two muscle-specific ubiquitin ligases E3, Atrogin-1/MAFbx and MuRF1.Taken together, these results demonstrate that a prolonged stimulation of mitochondrial activity induces muscle atrophy. In addition, these data underline the importance of a tight control of p43 expression and suggest that a deregulation of the direct T3 mitochondrial pathway could be one of the parameters involved in the occurrence of sarcopenia.

Catnip (Nepeta cataria) is an important medicinal herb belonging to the mint family, Lamiaceae. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from Nepeta cataria, and its essential oil composition were investigated. The essential oil, which has 4aalpha,7alpha,7abeta-nepetalactone (70.4%), 4aalpha,7alpha,7abeta-nepetalactone (6.0%), thymol (2.3%), and 4aalpha,7alpha, 7abeta3-nepetalactone (2.5%), as main components, exhibited activity against eleven bacteria, and twelve fungi and a yeast, C. albicans; with Minimum Inhibitory Concentrations (MIC) values ranging from 12.50 to 250 microl/ml; the methanol extract showed weaker activity. The samples were also subjected to a screening for their possible antioxidant activities by using 2.2-diphenyl-1-picrylhydrazyl (DPPH) and beta-carotene/linoleic acid assays. In DPPH assay, the extract showed slight antioxidant activity whereas the essential oil remained inactive. In the latter case, both the extract and the essential oil exerted weak activity having inhibiton ratios of linoleic acid oxidation at 16.4% and 27.0%, respectively. The weak antioxidative nature of the extract could be attributed to the low phenolic content, estimated as gallic acid equivalent at 22.6 +/- 2.07 microg/ml or 2.26%. In both systems, antioxidant capacity of BHT was determined in parallel experiments.

In previous studies, we have characterized a new hormonal pathway involving a mitochondrial T3 receptor (p43) acting as a mitochondrial transcription factor and consequently stimulating mitochondrial activity and mitochondrial biogenesis. We have established the involvement of this T3 pathway in the regulation of in vitro myoblast differentiation. We have generated mice overexpressing p43 under control of the human alpha-skeletal actin promoter. In agreement with the previous characterization of this promoter, northern-blot and western-blot experiments confirmed that after birth p43 was specifically overexpressed in skeletal muscle. As expected from in vitro studies, in 2-month old mice, p43 overexpression increased mitochondrial genes expression and mitochondrial biogenesis as attested by the increase of mitochondrial mass and mt-DNA copy number. In addition, transgenic mice had a body temperature 0.8 degrees C higher than control ones and displayed lower plasma triiodothyronine levels. Skeletal muscles of transgenic mice were redder than wild-type animals suggesting an increased oxidative metabolism. In line with this observation, in gastrocnemius, we recorded a strong increase in cytochrome oxidase activity and in mitochondrial respiration. Moreover, we observed that p43 drives the formation of oxidative fibers: in soleus muscle, where MyHC IIa fibers were partly replaced by type I fibers; in gastrocnemius muscle, we found an increase in MyHC IIa and IIx expression associated with a reduction in the number of glycolytic fibers type IIb. In addition, we found that PGC-1alpha and PPARdelta, two major regulators of muscle phenotype were up regulated in p43 transgenic mice suggesting that these proteins could be downstream targets of mitochondrial activity. These data indicate that the direct mitochondrial T3 pathway is deeply involved in the acquisition of contractile and metabolic features of muscle fibers in particular by regulating PGC-1alpha and PPARdelta.

Hippomarathrum microcarpum grows wild in eastern Anatolia, Turkey, and is a plant utilized as food by people. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from H. microcarpum and its essential oil composition were investigated. The essential oil, which has bornyl acetate, caryophyllene oxide, and beta-caryophyllene as its main components, exhibited activity against eight bacteria, nine fungi, and a yeast, Candida albicans, with minimum inhibitory concentration values ranging from 62.50 to 125 muL/mL; the methanol extract showed weak activity. The antioxidant activity of these extracts was assessed by the beta-carotene bleaching test and the 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test. The inhibition of linoleic acid oxidation was very weak for both extracts tested. The inhibition percentages were found to be 22.9 and 33.5% for methanol and essential oil, respectively, at the concentration of 2 g/L. The oil scavenged DPPH at higher concentrations (IC50 = 10.69 +/- 0.05 mg/mL), but the methanol extract exhibited no activity. The total phenolic content of the methanol extract was found to be 4.7 +/- 0.1%.

Objective: The study aimed to investigate the anatomy of the lateral nasal wall to provide a set of measurements among some important anatomical landmarks and to reveal the relationship between them., Methods: Fifty half heads were dissected to determine the distances between important landmarks in the lateral nasal wall for endoscopic sinus surgery. Landmarks were measured with an electronic caliper. This study was carried out between December 2002 and February 2003 at the Anatomy Research Laboratory, Faculty of Medicine, Akdeniz University, Antalya, Turkey., Results: Results were provided as mean +/- standard deviation. In our study, some of the critical distances as in the lateral nasal wall were measured and results showed consistency to the data found in the literature., Conclusion: Our results are useful to achieve safe endoscopic sinus surgery.

The oncogenic pathways in mitochondrial-rich thyroid carcinomas are not clearly understood. To investigate the possible implication of mitochondrial abundance in the genesis of thyroid tumors, we have explored the gene expression profile of six oncocytic carcinomas and six mitochondrial-rich papillary carcinomas using cDNA-microarray technology. A supervised approach allowed us to identify 83 genes differentially expressed in the two types of carcinoma. These genes were classified according to their ontologic profiles. Three genes, NOS3, alpha-actinin-2 and alpha-catenin, suspected of playing a role in tumor genesis, were explored by quantitative RT-PCR analysis and immunohistochemistry. Of the 59 genes overexpressed in papillary carcinomas, 51% were involved in cell communication. Of the 24 genes overexpressed in oncocytic carcinomas, 84% were involved in mitochondrial and cellular metabolism. Our results suggest that mitochondrial respiratory chain complexes III and IV play a significant role in the regulation of reactive oxygen species production by oncocytic tumors.

Thyroid oncocytic adenomas are a class of tumors characterized by the presence of abundant mitochondria. We performed a differential display RT-PCR analysis on two oncocytic adenomas and their paired controls. We then carried out a microarray analysis using the 460 selected, differentially expressed clones on four other oncocytomas and their paired controls. Thirty genes, 12 encoded by mitochondrial DNA and 18 nuclear-encoded, were overexpressed by a factor of at least 2 in the tumors compared with the controls. Seven of the 18 nuclear-encoded genes are involved in protein metabolism: DKFZP434I116, B3GTL, SNX19, RP42, SENP1, UBE2D3, and the CTSB gene, which is known to be particularly deregulated in most thyroid tumors. Other genes are implicated in signal transduction (ITGAV) or tumorigenesis (AF1q). Immunohistochemistry allowed us to confirm overexpression of the ITGAV and CTSB genes at the protein level and showed a marked relocation of the CTSB protein. We confirmed the overexpression of the AF1q oncogene in 56% of 18 oncocytic tumors by quantitative RT-PCR analysis, which attested to the heterogeneity of these tumors. Our results show an increased expression of genes involved in protein metabolism in oncocytoma, the significance of which requires investigation.

Oncocytomas are large cell tumors characterized by an abnormal proliferation of mitochondria. To investigate this phenomenon in thyroid oncocytomas, we determined gene expression profiles of 87 samples using microarrays of 6720 PCR products from cDNA clones. Samples included 29 thyroid oncocytomas and six papillary carcinomas, the remainder representing other thyroid pathologies or mitochondria-rich tumor samples, normal thyroid samples, and two thyroid cell lines. Hierarchical clustering and supervised analysis identified two specific oncocytic clusters and 163 distinctly regulated genes between oncocytoma and normal thyroid. Differential expression of five selected genes (APOD, BCL-2, COX, CTSB, and MAP2) was confirmed by immunohistochemistry. The two specific oncocytic clusters were rich in mitochondrial genes and revealed coordinated expression of nuclear and mitochondrial respiratory chain genes. We also observed the up-regulation of genes involved in mitochondrial biogenesis, such as nuclear respiratory factor 1 and the endothelial nitric oxide synthase. Several oxidative metabolism genes were overexpressed in oncocytomas, including those from the tricarboxylic acid cycle (MDH1) and cytosolic glycolysis (GAPD, ENO1, and GPI). On the contrary, the lactate dehydrogenase A gene, involved in anaerobic metabolism, was down-regulated. Our results suggest that, unlike a large number of solid tumors, thyroid oncocytomas produce energy through an aerobic pathway.

The OPA1 gene, encoding a dynamin-related GTPase that plays a role in mitochondrial biogenesis, is implicated in most cases of autosomal dominant optic atrophy (ADOA). Sixty-nine pathogenic OPA1 mutations have been reported so far. Most of these are truncating mutations located in the GTPase domain coding region (exons 8-16) and at the 3'-end (exons 27-28). We screened 44 patients with typical ADOA using PCR-sequencing. We also tested 20 sporadic cases of bilateral optic atrophy compatible with ADOA. Of the 18 OPA1 mutations found, 14 have never been previously reported. The novel mutations include one nonsense mutation, 3 missense mutations, 6 deletions, one insertion and 3 exon-skipping mutations. Two of these are de novo mutations, which were found in 2 patients with sporadic optic atrophy. The recurrent c.2708_2711delTTAG mutation was found in 2 patients with a severe congenital presentation of the disease. These results suggest that screening for OPA1 gene mutations may be useful for patients with optic atrophy who have no affected relatives, or when the presentation of the disease is atypical as in the case of early onset optic atrophy., (Copyright 2003 Wiley-Liss, Inc.)

Nuclear mitochondrial pseudogenes (Numts) have been found in the genome of many eukaryote species, including humans. Using a BLAST approach, we found 1105 DNA sequences homologous to mitochondrial DNA (mtDNA) in the August 2001 Goldenpath human genome database. We assembled these sequences manually into 286 pseudogenes on the basis of single insertion events and constructed a chromosomal map of these Numts. Some pseudogenes appeared highly modified, containing inversions, deletions, duplications, and displaced sequences. In the case of four randomly selected Numts, we used PCR tests on cells lacking mtDNA to ensure that our technique was free from genome-sequencing artifacts. Furthermore, phylogenetic investigation suggested that one Numt, apparently inserted into the nuclear genome 25-30 million years ago, had been duplicated at least 10 times in various chromosomes during the course of evolution. Thus, these pseudogenes should be very useful in the study of ancient mtDNA and nuclear genome evolution.