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121.

Background  

Using a functional genomics approach we addressed the impact of folate overproduction on metabolite formation and gene expression in Lactobacillus plantarum WCFS1. We focused specifically on the mechanism that reduces growth rates in folate-overproducing cells.  相似文献   
122.
Objective: To explore relationships of smoking and risk drinking status, nicotine and alcohol dependence, and anxiety, depressive, and somatoform disorders with overweight and obesity. Research Methods and Procedures: A probability sample was drawn that was representative for the adult general population, 18 to 64 years of age, in one region of Germany; the participation rate was 70.2%. After excluding those who were pregnant or had a current eating disorder according to the DSM‐IV, 4063 individuals remained. Overweight and obesity were defined according to the BMI that was assessed in the face‐to‐face in‐home standardized interview (Composite International Diagnostic Interview) on psychiatric disorders. Results: Men with a former nicotine dependence had higher odds of being overweight than men who never had a nicotine dependence (adjusted odds ratio, 1.5; confidence interval, 1.1 to 2.1). Men at current risk for drinking and current alcohol‐dependent or abusing men had lower odds of being overweight compared with men who never were alcohol dependent, abusing, or at risk for drinking (adjusted odds ratio, 0.3; confidence interval, 0.8 to 0.9). Effect sizes were small. No relationship of overweight with depressive, anxiety, or somatoform disorders was found in the multivariate analysis. Discussion: There is a relationship between being overweight and nicotine and alcohol dependence or abuse among men but not among women. Even though one reason for women to refrain from quitting smoking is the fear of weight gain, these results do not support this. This information could help convince women to try to quit smoking.  相似文献   
123.
The differences in shell structure and population turnover between organic-poor, impunctate (Hemithiris) and organic-rich, punctate brachiopod (Terebratalia) in a mixed-bottom, siliciclastic setting (San Juan Islands, WA) lead to different taphonomic damage and fidelity with respect to community-level abundance in death assemblages. In comparing shell interiors of similar-sized specimens, Terebratalia is predominantly affected by fibre detachment and shows almost no microbioerosion at the SEM scale; whereas, Hemithiris shows less marked fibre detachment at the SEM scale and is more intensely affected by microbioerosion both at SEM and light microscope (LM) scales. Fibre detachment related to rapid, microbially-induced organic matter decay appears to be the main destructive process acting on Terebratalia. Higher bioerosion levels in Hemithiris at SEM and LM scales are probably related to a combination of a low maceration rate and a preferential settlement by borers. From their vastly different abundances in life assemblages it can be deduced that Terebratalia produces dead shells at a much higher rate than Hemithiris. Therefore, the proportion of altered Terebratalia, relative to Hemithiris, is expected to be decreased due to its higher production of recently dead cohorts. That Terebratalia is also characterized by high damage levels shows that differential population turnover alone is not responsible for the differences in taphonomic damage. This shows that organic-rich and organic-poor shells are characterized by differential post-mortem durability. Although very few Hemithiris are present in the life assemblages, high durability ensures its relative over-representation in death assemblages. Terebratalia is not strongly under-represented in death assemblages, despite its high destruction rate, because of large production of recently dead shells. Even with the biasing effect of differential durability, the good fidelity reported in previous live-dead studies can be enhanced by higher population turnover of numerically dominant taxa, leading to constant input of recently dead shells into death assemblages.  相似文献   
124.
The hypothesis that plants grown under elevated CO2 allocate more carbon to the production of latex and C‐rich secondary compounds whereas nutrient addition counteracts this effect was tested. Two similar experiments were conducted in two different experimental facilities. In both facilities seedlings of Euphorbia lathyris were exposed to factorial combinations of two CO2 concentrations and two levels of nutrient availability for 2 months. The CO2 treatments and growth conditions differed substantially between these two experiments but treatment responses to elevated CO2 and fertilizer addition were remarkably similar, underlining the robustness of our findings. Elevated CO2 increased biomass to a greater extent in fertilized than in unfertilized plants and reduced the leaf biomass fraction by accelerating leaf senescence. Concentrations of non‐structural carbohydrates (NSC) increased in elevated CO2. However, this apparent carbon surplus did not feed into the whole plant latex pool. The latex harvest per leaf (?25%) and the concentration of latex‐related hydrocarbons (?20%) even decreased under elevated CO2 (both experiments P < 0.05). Fertilization reduced NSC concentrations (?25%) but neither affected latex yield per leaf nor the concentration of latex‐related hydrocarbons. It is concluded that latex and related hydrocarbons in CO2‐enriched plants are a negligible sink for excess carbon irrespective of nutrient status and thus, vigour of growth.  相似文献   
125.
Eps15 homology (EH) domain-containing proteins play a key regulatory role in intracellular membrane trafficking and cell signalling. EH domains serve as interaction platforms for short peptide motifs comprising the residues NPF within natively unstructured regions of accessory proteins. The EH-NPF interactions described thus far are of very low affinity and specificity. Here, we identify the presynaptic endocytic sorting adaptor stonin2 as a high-affinity ligand for the second EH domain (EH2) of the clathrin accessory protein Eps15. Calorimetric data indicate that both NPF motifs within stonin2 interact with EH2 simultaneously and with sub-micromolar affinity. The solution structure of this complex reveals that the first NPF motif binds to the conserved site on the EH domain, whereas the second motif inserts into a novel hydrophobic pocket. Our data show how combination of two EH-attachment sites provides a means for modulating specificity and allows discrimination from a large pool of potential binding partners containing NPF motifs.  相似文献   
126.
Summary A cytochemical study on the endothelium of the hypodermic lymphatic capillaries of the green lizard,Lacerta hispanica, has been carried out. The dialysed iron method produced a homogeneous precipitate on the surface of the endothelial cells and on the inside of the endocytic vesicles. The periodic acid-thiocarbohydrazide-silver proteinate, low pH phosphotungstic acid and high iron diamine techniques gave negative results. The carbohydrates in the capillaries thus seem to be glycosaminoglycans with carboxyl groups. The possible role of these glycosaminoglycans in the formation of the endocytic vesicles is discussed.  相似文献   
127.
Regioselective halogenation of electron rich substrates is catalysed by flavin-dependent halogenases. Thienodolin produced by Streptomyces albogriseolus contains a chlorine atom in the 6-position of the indole ring system and is believed to be derived from tryptophan. Using the gene of the tryptophan 7-halogenase (PrnA) from the pyrrolnitrin biosynthetic gene cluster the gene for a tryptophan 6-halogenase was cloned, sequenced and heterologously overexpressed in Pseudomonas strains. In vitro activity of the purified enzyme could only be shown in a two-component enzyme system consisting of the halogenase, a flavin reductase, NADH, FAD and halide ions. The enzyme catalyses the regioselective chlorination and bromination of l- and d-tryptophan. In its native form the enzyme is probably a homodimer with a relative molecular mass of the subunits of 63 600 (including the His-tag). Transformation of the pyrrolnitrin producer Pseudomonas chlororaphis ACN with a plasmid containing the tryptophan 6-halogenase gene lead to the formation of the new aminopyrrolnitrin derivative 3-(2′-amino-4′-chlorophenyl) pyrrole.  相似文献   
128.
All Illicium spp. have explosive fruits, which is a unique character among the basal grade of angiosperms. Illicium fruits consist of several ventrally dehiscing follicles developing from conduplicate carpels, with a prominent, slightly postgenitally fused ventral slit. The closure of the ventral slit is also secured by two mirror‐symmetrical massive longitudinal sclerenchymatous bands in the mesocarp along the edges and by turgor pressure. The pericarp differentiates into a fleshy (or coriaceous) peripheral zone (exocarp and mesocarp) with numerous ethereal‐oil‐containing cells and a sclerenchymatous (single‐layered, palisade) inner zone (endocarp). Dehydration of the fleshy zone of the pericarp and partial compression of the epidermal sclereids with U‐shaped wall thickenings lining the ventral suture are instrumental in explosive fruitlet dehiscence. Generally, the fruit structure of Illicium differs dramatically from those in other early diverging angiosperms. Gynoecium and fruit structure (and a probable early Cretaceous divergence from the SchisandraKadsura clade) provide evidence for treatment of Illicium as separate from Schisandraceae s.s. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013 , 171 , 640–654.  相似文献   
129.
Abstract.  The influence of long- and short-day cycles on ovipostion and egg hatch of the corn stalk borer, Sesamia nonagrioides were investigated at a range of temperatures. Oviposition was suppressed when insects are exposed to long days through their immature stages and then transferred to short days after mating. Moreover, mean oviposition and egg hatch increased from 15 to 27.5 °C, whereas oviposition declined significantly at 30 °C at both photoperiodic regimes. Females derived from a diapausing population exposed to long days after mating showed a significantly higher egg production compared to females derived from a nondiapausing population. However, when females from a diapausing population were left to oviposit under short days, fewer eggs were produced compared to those exposed to long days after mating. Thus, photoperiod appears to affect reproductive traits of this species in a quantitative manner. Larval diapause duration is positively correlated with fecundity of the adults. There is also a positive correlation between pupal weight of individuals derived from a diapausing population and the postdiapause fecundity of adults.  相似文献   
130.
Abstract.  We conducted the first comprehensive phylogenetic analysis of Psephenidae, based on 143 morphological characters of adults, larvae and pupae and coded for 34 taxa, representing three outgroups and 31 psephenid genera, including four undescribed ones. A strict consensus tree calculated (439 steps, consistency index = 0.45, retention index = 0.75) from the two most-parsimonious cladograms indicated that the monophyly of the family and subfamilies is supported, with the exception of Eubriinae, which is paraphyletic when including Afroeubria . Here a new subfamily, Afroeubriinae ( subfam.n. ), is formally established for Afroeubria . The analysis also indicated that the 'streamlined' larva is a derived adaptive radiation. Here, suprageneric taxonomy and the evolution of some significant characters are discussed. Keys are provided to the subfamilies and genera of Psephenidae considering larvae, adults and pupae.  相似文献   
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