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61.
Objective: To compare subcutaneous adipose tissue topography (SAT‐top) in obese juveniles with age‐matched normal‐weight controls. Research Methods and Procedures: The optical device LIPOMETER (European Patent EP 0516251) enables the non‐invasive, rapid, safe, and precise measurement of the thickness of subcutaneous adipose tissue. Fifteen defined body sites (1 = neck to 15 = calf) characterize the individual SAT‐top like an individual fingerprint. SAT‐top of 1351 juveniles (obese: 42 boys, 59 girls, normal weight: 680 boys, 570 girls) from 7 to 19 years of age were measured. For visual comparison, the 15‐dimensional SAT‐top information was condensed by factor analysis into a two‐dimensional factor plot. Results: Both female and male obese juveniles had markedly increased adipose tissue layers at 7 = upper abdomen, 8 = lower abdomen, 5 = front chest, and 6 = lateral chest. The pubertal changes of body shape and fat distribution of the normal‐weight boys and girls (boys show thinner adipose tissue layers on their legs, whereas girls had thicker adipose tissue layers at the extremities) were not seen in the obese group. Independently of age and sex, all of the obese juveniles showed a similar, more android body fat distribution with increased trunk fat. Discussion: SAT‐top of the obese juveniles is similar to that of patients with type 2 diabetes, polycystic ovary syndrome, and coronary heart disease. Patients with these metabolic disorders and obese juveniles are located in the factor plot in the same area. This body shape may indicate a risk profile for developing polycystic ovary syndrome (women), type 2 diabetes, and early atherosclerosis (both sexes).  相似文献   
62.
Two media used to mature adult porcine oocytes for somatic cell nuclear transfer were compared. In the first experiment, parthenogenetic embryos were produced using a maturation medium used by us previously to clone pigs (OMM199) and that described by Kühholzer et al. (2001) to transport oocytes overnight (BOMED). There was no difference in maturation rates between the two different media. However, BOMED medium increased the percentage of parthenogenetic embryos that developed to the blastocyst stage compared with OMM199 (49% vs. 29%, respectively). In a second experiment, BOMED medium increased the percentage of SCNT embryos that developed to the blastocyst stage compared with OMM199 (22% vs. 8%, respectively). The efficiency of our cloning protocol using adult oocytes matured in BOMED medium was then determined by transferring SCNT embryos reconstructed using adult fibroblasts to synchronized recipients. Primary cultures of adult fibroblasts were obtained from two adult male pigs and used for SCNT (passages 2-4). Between 82 and 146 fused couplets were transferred to seven recipients synchronized 1 day behind the embryos. Five recipients (71% pregnancy rate) subsequently farrowed a total of 23 piglets (4.4 average litter size). Overall efficiencies (liveborn/embryos transferred) were 3.2% for all transfers and 4.3% for animals that gave birth.  相似文献   
63.
Onconase is an extremely stable member of the RNase A superfamily. The increase in the thermodynamic stability by 20 kJ x mol(-1) in comparison to RNase A was expected to result in altered folding behavior. Despite the lack of cis-Pro residues in native Onconase, refolding at low concentrations of guanidine hydrochloride was complex and showed three kinetic phases (fast, medium, and slow), with rate constants differing by a factor of about 10 each. None of the phases could be accelerated by peptidyl-prolyl cis-trans isomerases, pointing to the absence of kinetic phases that are limited by Pro isomerization. The detailed analysis by various probes indicates that the burial of the N-terminal Trp3, which is associated with the restoration of the active site, occurs in the slow phase, i.e. in the last step of refolding. Evidently, in contrast to the folding of RNase A, there is no catalytically active native-like intermediate in the folding of Onconase.  相似文献   
64.
Phospholipases D play an important role in the regulation of cellular processes in plants and mammals. Moreover, they are an essential tool in the synthesis of phospholipids and phospholipid analogs. Knowledge of phospholipase D structures, however, is widely restricted to sequence data. The only known tertiary structure of a microbial phospholipase D cannot be generalized to eukaryotic phospholipases D. In this study, the isoenzyme form of phospholipase D from white cabbage (PLDalpha2), which is the most widely used plant phospholipase D in biocatalytic applications, has been characterized by small-angle X-ray scattering, UV-absorption, CD and fluorescence spectroscopy to yield the first insights into its secondary and tertiary structure. The structural model derived from small-angle X-ray scattering measurements reveals a barrel-shaped monomer with loosely structured tops. The far-UV CD-spectroscopic data indicate the presence of alpha-helical as well as beta-structural elements, with the latter being dominant. The fluorescence and near-UV CD spectra point to tight packing of the aromatic residues in the core of the protein. From the near-UV CD signals and activity data as a function of the calcium ion concentration, two binding events characterized by dissociation constants in the ranges of 0.1 mm and 10-20 mm can be confirmed. The stability of PLDalpha2 proved to be substantially reduced in the presence of calcium ions, with salt-induced aggregation being the main reason for irreversible inactivation.  相似文献   
65.
The genome size of the marine sponges Suberites domuncula and Geodia cydonium has been determined by flow cytofluorometric analysis using diamidino-phenylindole [DAPI]. Using human lymphocytes as reference the amount of DNA in cells from S. domuncula has been determined to be 3.7 pg and that of G. cydonium 3.3 pg. While no chromosomes could be identified in G. cydonium, the karyotype of the Suberites domuncula is 32 chromsomes in the diploid state. The size of the chromosomes was between 0.25 and 1.0 μm. No pronounced banding pattern was visible.  相似文献   
66.
The expression of two CTR-gene homologues was investigated during flower senescence in two Rosa hybrida cultivars. A fragment of a gene for a protein kinase, termed RhCTR1 (GenBank Acc. No. AF271206), was amplified by PCR and used to isolate the corresponding full-length cDNA (Acc. No. AY032953) from a rose petal cDNA library. The protein RhCTR1 has 66% amino acid identity to Arabidopsis CTR1. A fragment of a second CTR homologue, termed RhCTR2 (Acc. No. AY029067) is 69% identical to the corresponding region of RhCTR1. RhCTR1 expression increased during flower senescence, while RhCTR2 was constitutively expressed during flower development. The expression of both RhCTR1 and RhCTR2 was increased in response to exogenous ethylene.  相似文献   
67.
68.
The cellular and intracellular localization of the non-proteogenic amino acid nicotianamine (NA) in leaves and root elongation zones was immunochemically investigated in pea (Pisum sativum L.) and tomato (Lycopersicon esculentum Mill.) plants grown under various iron regimes and in three mutants defective in the regulation of iron uptake. Strongest immunostaining was observed in the over-accumulating pea mutants brz and dgl, and in iron-loaded wild-type plants. Fe concentration and NA level paralleled staining intensity, indicating that NA synthesis is induced by high iron availability. While label was mainly present in the cytoplasm under normal (10 microM) Fe supply and under Fe deprivation, most of the labeling was present in the vacuole in iron-loaded plants. This pattern resembled the distribution of NA in Fe over-accumulating mutants, indicating the possible importance of vacuolar sequestration in the detoxification of excess Fe. Based on the dependence of the cellular distribution of NA on the iron nutritional status of the plant, a possible role of NA in buffering free Fe in root and leaf cells was inferred. We show here for the first time that the NA concentration is increased in response to iron overload, indicating that, besides other classes of intracellular metal-binding ligands, NA may play an essential role in iron tolerance.  相似文献   
69.
Background

More than 70 cytoplasmic male sterility (CMS) types have been identified in Helianthus, but only for less than half of them, research of mitochondrial organization has been conducted. Moreover, complete mitochondrion sequences have only been published for two CMS sources – PET1 and PET2. It has been demonstrated that other sunflower CMS sources like MAX1, significantly differ from the PET1 and PET2 types. However, possible molecular causes for the CMS induction by MAX1 have not yet been proposed. In the present study, we have investigated structural changes in the mitochondrial genome of HA89 (MAX1) CMS sunflower line in comparison to the fertile mitochondrial genome.

Results

Eight significant major reorganization events have been determined in HA89 (MAX1) mtDNA: one 110 kb inverted region, four deletions of 439 bp, 978 bp, 3183 bp and 14,296 bp, respectively, and three insertions of 1999 bp, 5272 bp and 6583 bp. The rearrangements have led to functional changes in the mitochondrial genome of HA89 (MAX1) resulting in the complete elimination of orf777 and the appearance of new ORFs - orf306, orf480, orf645 and orf1287. Aligning the mtDNA of the CMS sources PET1 and PET2 with MAX1 we found some common reorganization features in their mitochondrial genome sequences.

Conclusion

The new open reading frame orf1287, representing a chimeric atp6 gene, may play a key role in MAX1 CMS phenotype formation in sunflower, while the contribution of other mitochondrial reorganizations seems to appear negligible for the CMS development.

  相似文献   
70.
Spirochetes of the genus Treponema are surprisingly abundant in termite guts, where they play an important role in reductive acetogenesis. Although they occur in all termites investigated, their evolutionary origin is obscure. Here, we isolated the first representative of ‘termite gut treponemes’ from cockroaches, the closest relatives of termites. Phylogenomic analysis revealed that Breznakiella homolactica gen. nov. sp. nov. represents the most basal lineage of the highly diverse ‘termite cluster I', a deep-branching sister group of Treponemataceae (fam. ‘Termitinemataceae’) that was present already in the cockroach ancestor of termites and subsequently coevolved with its host. Breznakiella homolactica is obligately anaerobic and catalyses the homolactic fermentation of both hexoses and pentoses. Resting cells produced acetate in the presence of oxygen. Genome analysis revealed the presence of pyruvate oxidase and catalase, and a cryptic potential for the formation of acetate, ethanol, formate, CO2 and H2 - the fermentation products of termite gut isolates. Genes encoding key enzymes of reductive acetogenesis, however, are absent, confirming the hypothesis that the ancestral metabolism of the cluster was fermentative, and that the capacity for acetogenesis from H2 plus CO2 - the most intriguing property among termite gut treponemes - was acquired by lateral gene transfer.  相似文献   
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