Transfer of reducing equivalents into mitochondria by the interconversions of proline and Δ1-pyrroline-5-carboxylate

Direct evidence is presented for a proline cycle using a cell-free experimental system which sequentially transfers ³H from [1-³H]glucose to NADP⁺ to Δ¹-pyrroline-5-carboxylate and yields [³H]proline. The formation of [³H]proline depends on the presence of NADP, Δ¹-pyrroline-5-carboxylate, and the enzymes glucose-6-phosphate dehydrogenase and Δ¹-pyrroline-5-carboxylate reductase. The production of [³H]proline from unlabeled proline in the presence of mitochondria provides direct evidence for one complete turn of a proline cycle which transfers reducing equivalents produced by glucose oxidation in the pentose pathway into mitochondria. In this cycle, proline is oxidized to Δ¹-pyrroline-5-carboxylate by mitochondrial proline oxidase. Δ¹-pyrroline-5-carboxylate is released from mitochondria and is recycled back to proline by Δ¹-pyrroline-5-carboxylate reductase with concomitant oxidation of NADPH. At the maximal rate observed, 60% of Δ¹-pyrroline-5-carboxylate produced is recycled back to proline. This cycle provides a mechanism for transferring reducing equivalents from NADPH into mitochondria and is linked to glucose oxidation in the pentose pathway by NADPH turnover.     

A phylogenetic analysis of species in the Bufo crucifer group (Anura: Bufonidae), based on indolealkylamines and proteins from skin secretions

This research tested the utility of two classes of skin secretion compounds to the phylogeny of the Bufo crucifer group. Skin secretions from specimens of nine populations of B. crucifer group were obtained and submitted to qualitative analysis. We observed a clear difference in the composition of the skin secretion molecules obtained from the species of Bufo studied. Fifty-nine molecules, 16 indolealkylamines and 43 proteins, were used as characters, and 39 of these were parsimonious informative. The tree topology of the skin secretion combined data showed areas of congruence and conflict when compared to an mtDNA phylogeny of the B. crucifer group. We used the Templeton test to evaluate the heterogeneity between the skin secretion and mtDNA data. Although not recommended, we performed a combined analysis with the two partitions. The skin secretion characters from the species of Bufo studied have phylogenetic signal. These data are indicative, at least as a preliminary study, of the phylogenetic relationships among the B. crucifer group taxa.     

Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer

The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular FAs and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto, all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labeled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome and induced repartitioning of n-3 and n-6 PUFAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics.     

Environmental and genetic control of crassulacean acid metabolism in two crassulacean species and an F1 hybrid with differing biomass δ13C values

Abstract The growth, biomass δ¹³C values, and ability to accumulate titratable acidity at night were compared in eight environmental treatments for Cremnophila linguifolia, Sedum greggii, and their F₁ hybrid. In the phytotron, differences in treatment daylength, day/night temperature and water availability were all found to have effects on total plant dry weight, nocturnal accumulation of titratable acidity and biomass δ¹³C value of at least some of the genotypes. However, there were differences between the genotypes both in the magnitude and direction of response of the phenotypic properties to the treatment variables. The phytotron δ¹³C values ranged from -12.9 to -19.2‰ for C. linguifolia, from -22.2 to -33.4‰ for S. greggii, and from -19.2 to -24.9‰ for the hybrid. After with-holding water for 76 h both C. linguifolia and the hybrid had midday Ψ_leaf values of -0.23 MPa; however, S. greggii had a value of -1.05 MPa. In contrast to past observations of other species, the daily watered plants of C. linguifolia had less negative δ¹³C values than did the plants watered only weekly.     

谷子和狗尾草核型分析

作者研究了我国谷子(Setaria italica Beauv.)和狗尾草的核型与Giemsa带,两者核型基本相同,均为2n=18=14m+2sm+2st(SAT)。带型亦相近,另外在谷子和狗尾草中都发现有四倍体。     

Interrelationships of Staphyliniform groups inferred from 18S and 28S rDNA sequences, with special emphasis on Hydrophiloidea (Coleoptera, Staphyliniformia)

The series Staphyliniformia is one of the mega‐diverse groups of Coleoptera, but the relationships among the main families are still poorly understood. In this paper we address the interrelationships of staphyliniform groups, with special emphasis on Hydrophiloidea and Hydraenidae, based on partial sequences of the ribosomal genes 18S rDNA and 28S rDNA. Sequence data were analysed with parsimony and Bayesian posterior probabilities, in an attempt to overcome the likely effect of some branches longer than the 95% cumulative probability of the estimated normal distribution of the path lengths of the species. The inter‐family relationships in the trees obtained with both methods were in general poorly supported, although most of the results based on the sequence data are in good agreement with morphological studies. In none of our analyses a close relationship between Hydraenidae and Hydrophiloidea was supported, contrary to the traditional view but in agreement with recent morphological investigations. Hydraenidae form a clade with Ptiliidae and Scydmaenidae in the tree obtained with Bayesian probabilities, but are placed as basal group of Staphyliniformia (with Silphidae as subordinate group) in the parsimony tree. Based on the analysed data with a limited set of outgroups Scarabaeoidea are nested within Staphyliniformia. However, this needs further support. Hydrophiloidea s.str., Sphaeridiinae, Histeroidea (Histeridae + Sphaeritidae), and all staphylinoid families included are confirmed as monophyletic, with the exception of Hydraenidae in the parsimony tree. Spercheidae are not a basal group within Hydrophiloidea, as has been previously suggested, but included in a polytomy with other Hydrophilidae in the Bayesian analyses, or its sistergroup (with the inclusion of Epimetopidae) in the parsimony tree. Helophorus is placed at the base of Hydrophiloidea in the parsimony tree. The monophyly of Hydrophiloidea s.l. (including the histeroid families) and Staphylinoidea could not be confirmed by the analysed data. Some results, such as a placement of Silphidae as subordinate group of Hydraenidae (parsimony tree), or a sistergroup relationship between Ptiliidae and Scydmaenidae, appear unlikely from a morphological point of view.     

Screening environmental samples for source-specific bacteriophage hosts using a method for the simultaneous pouring of 12 petri plates

A simple apparatus was developed to allow 12 petri plates to be poured simultaneously by hand. It was used when screening bacterial isolates from sewage and dog feces for their ability to detect phages from these sources. This was done to assess the ease with which source-specific phage hosts can be isolated from these sources of fecal pollution. Host bacteria that consistently detected phages from sewage were easily isolated from sewage. These bacterial isolates did not detect phages from dog feces. Host bacteria were not isolated from dog feces even after screening hundreds of colonies from fecal samples from six dogs. Journal of Industrial Microbiology & Biotechnology (2000) 24, 124–126. Received 06 July 1999/ Accepted in revised form 05 November 1999     

Cortinarius sarcoflammeus sp. nov, a new species of subgenus Dermocybe (Agaricales) growing in Sphagnum bogs

 Cortinarius sarcoflammeus is proposed as a new species belonging to subgenus Dermocybe, on the basis of its morphological, chemical and ecological characters. The strong red-orange colour of the context and stipe base, large spores, sphagnicolous habitat and high dermorubin content are characteristic for the new species. Holotypes of C. huronensis and C. huronensis var. olivaceus have been examined for comparison, and their differences discussed. Photographs and line drawings of C. sarcoflammeus are added. Received February 13, 2001 Accepted March 23, 2001