White fat progenitor cells reside in the adipose vasculature   总被引：1，自引：0，他引：1  

Tang W  Zeve D  Suh JM  Bosnakovski D  Kyba M  Hammer RE  Tallquist MD  Graff JM 《Science (New York, N.Y.)》2008,322(5901):583-586

White adipose (fat) tissues regulate metabolism, reproduction, and life span. Adipocytes form throughout life, with the most marked expansion of the lineage occurring during the postnatal period. Adipocytes develop in coordination with the vasculature, but the identity and location of white adipocyte progenitor cells in vivo are unknown. We used genetically marked mice to isolate proliferating and renewing adipogenic progenitors. We found that most adipocytes descend from a pool of these proliferating progenitors that are already committed, either prenatally or early in postnatal life. These progenitors reside in the mural cell compartment of the adipose vasculature, but not in the vasculature of other tissues. Thus, the adipose vasculature appears to function as a progenitor niche and may provide signals for adipocyte development.  相似文献   

Mass spectrometry of intact V-type ATPases reveals bound lipids and the effects of nucleotide binding     

Zhou M  Morgner N  Barrera NP  Politis A  Isaacson SC  Matak-Vinković D  Murata T  Bernal RA  Stock D  Robinson CV 《Science (New York, N.Y.)》2011,334(6054):380-385

The ability of electrospray to propel large viruses into a mass spectrometer is established and is rationalized by analogy to the atmospheric transmission of the common cold. Much less clear is the fate of membrane-embedded molecular machines in the gas phase. Here we show that rotary adenosine triphosphatases (ATPases)/synthases from Thermus thermophilus and Enterococcus hirae can be maintained intact with membrane and soluble subunit interactions preserved in vacuum. Mass spectra reveal subunit stoichiometries and the identity of tightly bound lipids within the membrane rotors. Moreover, subcomplexes formed in solution and gas phases reveal the regulatory effects of nucleotide binding on both ATP hydrolysis and proton translocation. Consequently, we can link specific lipid and nucleotide binding with distinct regulatory roles.  相似文献   

Organic-geochemical Differentiation of Petroleum-type Pollutants and Study of Their Fate in Danube Alluvial Sediments and Corresponding Water (Pančevo Oil Refinery, Serbia)     

Branimir Jovančićević  Miroslav Vrvić  Jan Schwarzbauer  Hermann Wehner  Georg Scheeder  Dragomir Vitorović 《Water, air, and soil pollution》2007,183(1-4):225-238

A review is given in this paper of the up-to-date results observed in differentiation and transformation studies on petroleum-type pollutants in underground and surface waters. Water and particulate matter derived from the locality of Pan?evo Petroleum Refinery, Serbia (River Danube alluvial formations). It was shown that distributions of n-alkanes, steranes and triterpanes, and δ¹³C_PDB values of n-alkanes may successfully be used for qualitatively differentiating the petroleum-type pollutants from native organic matter in recent sedimentary formations. In underground waters, a petroleum-type pollutant is exposed to microbiological degradation which is manifested through relatively fast degradation of n-alkanes. Following an almost complete degradation of crude oil n-alkanes in underground water, the biosynthesis of novel, even carbon-number C₁₆–C₃₀ n-alkanes may be observed. It is shown that the n-alkane distribution observed in a petroleum-type pollutant may depend on the intensity of its previous interaction with water. The fate of petroleum-type pollutants in environmental waters may be predicted through laboratory simulative microbiological degradation experiments by using microorganism consortiums similar to those observed under relevant natural conditions, as well as on corresponding nutrient base.  相似文献   

Spatial and vertical distribution of <Superscript>137</Superscript>Cs in soils in the erosive area of southeastern Serbia (Pčinja and South Morava River Basins)     

Jelena Petrović  Snežana Dragović  Ranko Dragović  Milan Đorđević  Mrđan Đokić  Mirjana Ćujić 《Journal of Soils and Sediments》2016,16(4):1168-1175

  相似文献   

Effects of root exudates and humic substances on weathering kinetics     

Michael Ochs  Ivano Brunner  Werner Stumm  BoŽena ćosović 《Water, air, and soil pollution》1993,68(1-2):213-229

The effect of complex natural organic ligands on the weathering kinetics of aluminum oxide was investigated in laboratory experiments. A peat-derived humic substance and root exudates obtained from ectomycorrhizal (Picea abies — Hebeloma crustuliniforme) and non-mycorrhizal Norway Spruce trees; and γ-Al₂O₃ were used as a model system. The experimental weathering rates are in accordance with a surface-controlled dissolution mechanism. The effect of the humic material on dissolution rates appears to depend on the degree of protonation of the humic (macro)molecules: we observed dissolution-enhancement or -inhibition at pH 3 and 4, respectively. Ectomycorrhizal exudates proved to be effective weathering agents at pH 4, as opposed to humic material and non-mycorrhizal exudates. Our results suggest that (i) the role of humic materials in mineral weathering and podzolization is different from what is commonly thought, and (ii) mineral weathering rates in the rhizosphere may be higher than in the bulk soil.  相似文献   

Principal component analysis of trace elements in Serbian wheat     

Skrbić B  Durisić-Mladenović N  Cvejanov J 《Journal of agricultural and food chemistry》2005,53(6):2171-2175

Trace elements (Cu, Fe, Pb, Hg, Cd, As, Mn, Zn) were analyzed quantitatively in 14 wheat samples collected from fields in all Serbian growing regions, harvested in 2002. Microelements were determined according to an atomic absorption spectrophotometric method. Principal component analyses (PCA) were performed on data matrices consisting of contents of trace elements in wheats (columns) and all Serbian wheat-growing regions (rows). It was found that four principal components account for 87.2% of the total variance in the data. The plot of component loadings showed significant groupings for concentration of some microelements. The component scores indicated the similarities among the Serbian wheat-growing regions. The loading plot reveals that there is no need to measure all of the variables to achieve the same classification. It is enough to measure one variable per group. Naturally, this conclusion is valid only within the limits of the present study of wheat grain samples from different parts of Serbia.  相似文献   

Influence of grain type on the insecticidal efficacy of two diatomaceous earth formulations against Rhyzopertha dominica (F) (Coleoptera: Bostrychidae)     

Kavallieratos NG  Athanassiou CG  Pashalidou FG  Andris NS  Tomanović Z 《Pest management science》2005,61(7):660-666

Laboratory bioassays were carried out in order to evaluate the effectiveness of two diatomaceous earth (DE) formulations, Insecto and SilicoSec, against adults of Rhyzopertha dominica (F) in eight different grain commodities. The adherence of the two DEs to each grain was also measured. The eight grains tested were wheat, whole barley, peeled barley, oats, rye, triticale, rice and maize. These commodities were treated with the DEs at three rates, 0.75, 1.0 and 1.5 g DE kg(-1) grain. The mortality of R dominica adults was measured after 24 h, 48 h, 7 days and 14 days of exposure in the treated grains at 26 degrees C and 55% RH. After the 14-day mortality count, all adults were removed and the treated grains retained under the same conditions for a further 60 days. The treated grains were subsequently examined for F1 progeny. Significant differences were recorded among the eight grain types as well as between the DE formulations tested. After 14 days of exposure, even at the lowest DE rate for both formulations, adult mortality was high (>90%) in wheat and triticale. In contrast, adult mortality was significantly lower in peeled barley. Increasing the rate improved the efficacy of the DEs significantly in only some of the grains tested. Reproductive capacity in all the treated grains was significantly suppressed when compared with untreated grains. Generally, more F1 individuals of R dominica were noted in the treated peeled barley than in the other commodities. Significant differences in the percentage of DE retention were noted among the eight grains. The highest retention level was noted in rice (>87%) and the lowest in maize (<6%). However, the degree of DE adherence to a given grain was not always indicative of the effectiveness of DE against R dominica.  相似文献   

Monitoring and treatment of Fascioloides magna in semi-farm red deer husbandry in Croatia     

Janicki Z  Konjević D  Severin K 《Veterinary research communications》2005,29(Z2):83-88

The presence of American liver fluke (Fascioloides magna) in Croatian wild ruminant species was detected for the first time in January 2000. At the same time, the problem of adequate parasitological monitoring and treatment appeared in the captive deer population. Quarantine and health screening protocols, as well as migration and transportation influence had to be evaluated in red deer husbandry. Non-invasive methods were introduced to estimate the prevalence of F. magna in the semi-farm rearing system. Coprological analysis has been performed on 264 faecal samples. The most effective antiparasitic treatment was implemented on herd and individual treatment. Treatment was extended to the free-ranging population of deer in the same region.  相似文献   

Antimutagenic effects of extracts from sage (Salvia officinalis) in mammalian system in vivo     

Vujosević M  Blagojević J 《Acta veterinaria Hungarica》2004,52(4):439-443

Naturally occurring antimutagenic factors, especially those of plant origin, have recently become a subject of intensive research. Antimutagenic properties of terpenoid fractions of sage (Salvia officinalis) were tested in mammalian system in vivo through examining the ability of sage to decrease the frequency of aberrant cells induced by a potent mutagen. First, groups of mice were treated with three concentrations of sage alone and it was established that the frequency of aberrant cells after treatment with a concentration of 25 microL/kg was not significantly different from the negative control (olive oil), while that found after treatment with the 50 microL/kg concentration differed significantly (chi2(1) = 4.05, p < 0.05). Sage used at a concentration of 100 microL/kg was cytotoxic. Mitomycin C (MMC), known as a potent mutagen, was used for induction of chromosome aberrations. Post-treatment with sage suppressed the effects of MMC significantly. Both concentrations (25 microL/kg and 50 microL/kg) produced a significant decrease in the frequency of aberrations relative to MMC (chi2(1) = 5.42, p < 0.02, chi2(1) = 14.93, p < 0.001, respectively). The percent of aberrations decreased with increasing concentrations of sage. Only nontoxic concentrations of sage without mutagenic effects can be recommended for use as inhibitors of mutagenesis or carcinogenesis.  相似文献   

Antimicrobial resistance of Salmonella isolated from finishing swine and the environment of 60 Alberta swine farms   总被引：5，自引：0，他引：5  

Rajić A  McFall ME  Deckert AE  Reid-Smith R  Manninen K  Poppe C  Dewey CE  McEwen SA 《Veterinary microbiology》2004,104(3-4):189-196

The study objective was to describe and evaluate antimicrobial resistance profiles in Salmonella isolated from Alberta swine finishing farms. Salmonella isolates (n = 322) were obtained from 192 fecal and 84 environmental samples of the 60 Salmonella-positive swine finishing farms. Isolates were classified susceptible, intermediate or resistant based on NCCLS guidelines. More than half of the isolates (53.4%) were susceptible to all of the 18 antimicrobials in the testing panel. No resistance was observed to amikacin, amoxicillin/clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, cephalothin, ciprofloxacin, imipenem or nalidixic acid. Less than 1% of isolates were resistant to apramycin, gentamicin and trimethoprim/sulfamethoxazole. Higher frequencies of resistance were observed for chloramphenicol (4.7%), ampicillin (7.8%), kanamycin (11.8%), sulfamethoxazole (21.1%), streptomycin (25.5%) and tetracycline (38.8%). Eleven Salmonella serovars had isolates with resistance to > or =3 antimicrobials. The most frequently resistant serovar was Salmonella Derby, with 27 (38.0%) isolates resistant to > or =3 antimicrobials, including resistance to five and six antimicrobials. An absence of resistance to cephalosporins and fluoroquniolones and a low proportion of isolates resistant to amikacin, amoxicillin/clavulanic acid, apramycin, gentamicin and trimethoprim/sulfamethoxazole are encouraging findings from public health and animal health perspectives. Frequent resistance observed for ampicillin, kanamycin, sulfamethoxazole, streptomycin and tetracycline, antimicrobials commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved.  相似文献