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941.
The diet of the red fox Vulpes vulpes was investigated in five regions of northeastern Poland by stomach content analysis of 224 foxes collected from hunters. The red fox is expected to show the opportunistic feeding habits. Our study showed that foxes preyed mainly on wild prey, with strong domination of Microtus rodents, regardless of sex, age, month and habitat. Voles Microtus spp. were found in 73% of stomachs and constituted 47% of food volume consumed. Other food items were ungulate carrion (27% of volume), other mammals (11%), birds (9%), and plant material (4%). Sex- and age-specific differences in dietary diversity were found. Adult males and juvenile foxes had larger food niche breadths than adult females and their diets highly overlapped. Proportion of Microtus voles increased from autumn to late winter. Significant habitat differences between studied regions were found. There was a tendency among foxes to decrease consumption of voles with increasing percentage of forest cover. Based on our findings, red foxes in northeastern Poland can be recognized as a generalist predators, consuming easily accessible and abundant prey. However, high percentage of voles consumed regardless of age, sex, month, or habitats may indicate red fox specialization in preying on Microtus rodents.  相似文献   
942.
943.
The genetic and biochemical aspects of the essential Mycobacteriumtuberculosis MtrAB two-component regulatory signal transduction (2CRS) system have not been extensively investigated. We show by bacterial two-hybrid assay that the response regulator (RR) MtrA and the sensor kinase MtrB interact. We further demonstrate that divalent metal ions [Mg2+, Ca2+ or both] promote MtrB kinase autophosphorylation activity, but only Mg2+ promotes phosphotransfer to MtrA. Replacement of the conserved aspartic acid residues at positions 13 and 56 with alanine (D13A), glutamine (D56E) or asparagine (D56N) prevented MtrA phosphorylation, indicating that these residues are important for phosphorylation. The MtrA(D56E) and MtrA(D13A) proteins bound to the promoter of fbpB, the gene encoding antigen 85B protein, efficiently in the absence of phosphorylation, whereas MtrA(D56N) did not. We also show that M.tuberculosismtrA merodiploids overproducing MtrA(D13A), unlike cells overproducing wild-type MtrA, grow poorly in nutrient broth and show reduced expression of fbpB. These latter findings are reminiscent of a phenotype associated with MtrA overproduction during intramacrophage growth. Our results suggest that MtrA(D13A) behaves like a constitutively active response regulator and that further characterization of mtrA merodiploid strains will provide valuable clues to the MtrAB system.  相似文献   
944.
Nucleotide sugar transporters deliver nucleotide sugars into the Golgi apparatus and endoplasmic reticulum. This study aimed to further characterize mammalian UDP-galactose transporter (UGT) in MDCK and CHO cell lines. MDCK-RCAr and CHO-Lec8 mutant cell lines are defective in UGT transporter, although they exhibit some level of galactosylation. Previously, only single forms of UGT were identified in both cell lines, UGT1 in MDCK cells and UGT2 in CHO cells. We have identified the second UGT splice variants in CHO (UGT1) and MDCK (UGT2) cells. Compared to UGT1, UGT2 is more abundant in nearly all examined mammalian tissues and cell lines, but MDCK cells exhibit different relative distribution of both splice variants. Complementation analysis demonstrated that both UGT splice variants are necessary for N- and O-glycosylation of proteins. Both mutant cell lines produce chondroitin-4-sulfate at only a slightly lower level compared to wild-type cells. This defect is corrected by overexpression of both UGT splice variants. MDCK-RCAr mutant cells do not produce keratan sulfate and this effect is not corrected by either UGT splice variant, overexpressed either singly or in combination. Here we demonstrate that both UGT splice variants are important for glycosylation of proteins. In contrast to MDCK cells, MDCK-RCAr mutant cells may possess an additional defect within the keratan sulfate biosynthesis pathway.  相似文献   
945.
The migration, survival and proliferation of cells is the basis for all physiologic and pathologic processes in the human body. All these reactions are regulated by a complex chemokine network that guides lymphocytes homing, chemotaxis, adhesion and interplay between immunologic system response cells. Chemokines are also responsible for metastatic dissemination of cancers, including Hodgkin's and non-Hodgkin's lymphomas. The purpose of this study was to determine chemokine gene expression (CXCL8, CXCL10, CCL2, CCL3, CCL4 and CCL5) in lymphoma lymph nodes compared to their expression in reactive lymph nodes. We also analyzed the influence of chemokine gene expression on the survival of lymphoma patients. Chemokine gene expression was evaluated in 37 lymphoma lymph nodes and in 25 samples of reactive lymph nodes. Gene expression of chemokines CXCL8, CXCL10, CCL2, CCL3, CCL4 and CCL5 was measured using the PCR method. Statistical analysis was performed using CSS Statistica for Windows (version 7.0) software. Probability values 〈 〈 0.05 were considered statistically significant and those between 0.05 and 0.1 as indicative of a trend. We found lower CXCL8 and CXCL10 gene expression in lymphoma lymph nodes compared to reactive lymph nodes. In the cases of CCL2 and CCL3, expression in lymphomas was higher than in reactive lymph nodes. Patients with high expression of CCL2 and CXCL10 had shorter survival.  相似文献   
946.
A tertiary structure of recombinant A22G-B31K-B32R-human insulin monomer (insulin GKR) has been characterized by 1H, 13C NMR at natural isotopic abundance using NOESY, TOCSY, 1H/13C-GHSQC, and 1H/13C-GHSQC-TOCSY spectra. Translational diffusion studies indicate the monomer structure in water/acetonitrile (65/35 vol.%). CSI analysis confirms existence of secondary structure motifs present in human insulin standard (HIS). Both techniques allow to establish that in this solvent recombinant insulin GKR exists as a monomer. Starting from structures calculated by the program CYANA, two different refinement protocols used molecular dynamics simulated annealing with the program AMBER; in vacuum (AMBER_VC), and including a generalized Born solvent model (AMBER_GB). From these calculations an ensemble of 20 structures of lowest energy was chosen which represents the tertiary structure of studied insulin. Here we present novel insulin with added A22G amino acid which interacts with β-turn environment resulting in high flexibility of B chain C-terminus.  相似文献   
947.
The purpose of the present work was to evaluate carrot plants obtained from anther cultures with respect to their ploidy and homozygosity. Ploidy was determined using flow cytometry. Homozygosity of analyzed plants was determined using isoenzymes, glucose-6-phosphate isomerase (PGI) and aspartate aminotransferase (AAT). The cytometric tests revealed that more than 90% of the carrot plants obtained from anther cultures were doubled haploid. In the initial assessment of polymorphism of the two enzymatic systems in selected androgenetic carrot plants of the cultivars: Berjo, Kazan F1, and Splendid F1, it was proven that 100% of those plants were homozygotes in respect to PGI and also with respect to AAT. In the second experiment, the obtained androgenetic progeny of the heterozygous donor plant of cultivar Narbonne F1 was found to be 94% homozygotic with respect to PGI and 100% homozygotic in the case of AAT. For the androgenetic plants of the cultivar Kazan F1, 89% of them were homozygotic with respect to AAT but PGI enzyme system did not differentiate the homozygotic and heterozygotic androgenetic progeny. These results indicated that enzyme polymorphism depends on carrot genotype, therefore, analysis of some (more than one) isozymes was necessary to confirm homozygosity of plants. PGI and AAT can be a useful tool for determining homozygosity in androgenetic carrot plants.  相似文献   
948.

Background

The S73/S97/loop motif is a hallmark of the Cdc34 family of E2 ubiquitin-conjugating enzymes that together with the SCF E3 ubiquitin ligases promote degradation of proteins involved in cell cycle and growth regulation. The inability of the loop-less Δ12Cdc34 mutant to support growth was linked to its inability to catalyze polyubiquitination. However, the loop-less triple mutant (tm) Cdc34, which not only lacks the loop but also contains the S73K and S97D substitutions typical of the K73/D97/no loop motif present in other E2s, supports growth. Whether tmCdc34 supports growth despite defective polyubiquitination, or the S73K and S97D substitutions, directly or indirectly, correct the defect caused by the loop absence, are unknown.

Results

tmCdc34 supports yeast viability with normal cell size and cell cycle profile despite producing fewer polyubiquitin conjugates in vivo and in vitro. The in vitro defect in Sic1 substrate polyubiquitination is similar to the defect observed in reactions with Δ12Cdc34 that cannot support growth. The synthesis of free polyubiquitin by tmCdc34 is activated only modestly and in a manner dependent on substrate recruitment to SCFCdc4. Phosphorylation of C-terminal serines in tmCdc34 by Cka2 kinase prevents the synthesis of free polyubiquitin chains, likely by promoting their attachment to substrate. Nevertheless, tm CDC34 yeast are sensitive to loss of the Ubp14 C-terminal ubiquitin hydrolase and DUBs other than Ubp14 inefficiently disassemble polyubiquitin chains produced in tm CDC34 yeast extracts, suggesting that the free chains, either synthesized de novo or recycled from substrates, have an altered structure.

Conclusions

The catalytic motif replacement compromises polyubiquitination activity of Cdc34 and alters its regulation in vitro and in vivo, but either motif can support Cdc34 function in yeast viability. Robust polyubiquitination mediated by the S73/S97/loop motif is thus not necessary for Cdc34 role in yeast viability, at least under typical laboratory conditions.  相似文献   
949.
This study investigates associations between gene expressions of aromatase (CYP19), 17α hydroxylase (CYP17), and estrogen receptors α and β and anthropometric measurements in offspring of the Michigan fish eater cohort. Leg and trunk length, height, weight, and BMI and gene expression in peripheral blood cells were measured in offspring of the Michigan fish eater cohort. The parental generation was followed between 1973 and 1991, and maternal age, height, and weight data were collected. Female offspring were contacted in 2001/2002 and followed up in 2006/2007; offspring information included age, education, reproductive history, smoking, and exercise. Gene expression was standardized against 18S ribosomal ribonucleic acid (18SrRNA) and RNA polymerase II (RNA PolII) expressions. Mixed models assessed the statistical effect of gene expression on anthropometric outcomes, accounting for multiple offspring from one mother. Anthropometric measurements and gene expression were measured in 139 female offspring. The two length and the height measurements were correlated, as were BMI and weight. CYP19 expression was correlated with the other gene expressions and both estrogen receptor expressions were associated. For every 1 unit of ΔCt (18SrRNACYP19) or ΔCt (RNA PolIICYP19), BMI was increased by 0.9 (P = 0.03) and 0.87 kg/m2 (P = 0.04), respectively, and weight by 2.35 kg (P = 0.03) and 2.1 kg (P = 0.03), respectively. For every 1 unit of ΔCt (18SrRNACYP17), leg length was increased by 0.84 cm (P = 0.04). The results suggest that CYP17 gene expression may influence growth during childhood and adolescence while CYP19 may be associated with the concurrent measures of weight and BMI.  相似文献   
950.

Induction of androgenesis, followed by chromosome doubling, is a crucial method to obtain complete homozygosity in one-generation route. However, in vitro androgenesis can result in various genetic and epigenetic changes in derived triticale plants. In this study, we evaluated chromosome alternations and we associated them with the changes of spike morphology in androgenic progeny of triticale. We karyotyped offspring plants that derived from double haploid plants using fluorescence in situ hybridization techniques. We distinguished four major groups of karyotypes: double ditelosomics, nullisomics N2R, nullisomics N5R, and triticale plants with a complete set of chromosomes. It is known that more than half of QTLs connected with androgenic response are located in R-genome of triticale but 2R, 5R, and 6R chromosomes are not included. We hypothesized that the reason why only aberrations of chromosomes 2R and 5R appear during androgenesis of triticale is that because these chromosomes are not involved in the stimulation of androgenic response and the following regeneration of plants is not disrupted. Concerning the established groups, we evaluated following quantitative traits: spike length, number of spikes per plant, number of spikelets per spike, and number of grains per spike. The nullisomy of chromosome 2R and 5R resulted in vast changes in spike architecture of triticale plants, which can be correlated with the location of major QTLs for spike morphology traits on these chromosomes. The spikes of nullisomic plants had significantly decreased spike length which correlated with the reduction of number of spikelets per spike and number of grains per spike.

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