The cis(c)-9, trans(t)-11 (c9,t11) and t10,c12 isomers of conjugated linoleic acid (CLA) have been reported as agonists of peroxisome proliferator-activated receptor (PPAR) and beneficial in lipidemia and glycemia. However, it is unclear whether CLA isomers enhance or antagonize effects of conventional drugs targeting PPAR. Male Sprague-Dawley rats were fed high fat diet (HFD) for 8 weeks and treated without or with CLA, rosiglitazone or both for 4 weeks. Oral glucose tolerance and surrogate markers of insulin resistance were not significantly different for all treatments compared to untreated normal diet (ND) or HFD group, except lipoprotein levels. The combination of CLA and rosiglitazone had suppressed levels of low and high density lipoproteins (46 % and 25 %, respectively), compared to HFD-alone. Conversely, the atherogenic co-efficient of the animals received HFD or HFD+rosiglitazone+CLA was 2-folds higher than ND, HFD+rosiglitazone or HFD+CLA. Isolated aortic rings from the combined CLA and rosiglitazone treated animals were less sensitive to isoprenaline-induced relaxation among endothelium-denuded aortas with a decreased efficacy and potency (Rmax=53±4.7 %; pEC50=6±0.2) compared to endothelium-intact aortas (Rmax=100±9.9 %; pEC50=7±0.2). Our findings illustrate that the combination of CLA and rosiglitazone precede the atherogenic state with impaired endotheliumindependent vasodilatation before the onset of HFD-induced insulin resistance., B. K. Chai, Y. S. Lau, B. J. Loong, M. M. Rais, K. N. Ting, D. M. Dharmani, S. K. Mohankumar., and Obsahuje bibliografii
By use of plastic or rubber admixtures in the stamped charges, it is possible to affect the properties of tar, in contrast to the calorific value of resulting coking gas; further, it was found that the reactivity- and strength parameters of the obtained blast-furnace coke are good or acceptable. Unused plastics or rubber can economize on part of the coal used in a stamped charge. Additions of both light and heavy plastics can be used up to 5 % of a charge weight; in the case of rubber it is not advisable to exceed 2 wt.-% in a charge. In contradiction to the other methods, which process the unused plastics of up to a content of 1 % in a charge, it is possible, in the case of used stamping method, to process even 2 % or more., Pavel Straka., and Obsahuje bibliografické odkazy
The abnormal proliferation of vascular smooth muscle cells (VSMC) is thought to play a role in the pathogenesis of atherosclerosis. Adipocytes produce several bioactive paracrine substances that can affect the growth and migration of VSMCs. Our study focuses on the direct effect of the bioactive substances in conditioned media (CM) that was obtained by incubation with primary adipocyte-derived cell lines, including cell lines derived from both preadipocytes and from more mature cells, on the proliferation rate of human aortic smooth muscle cells (HAoSMCs). We used a Luminex assay to measure the adipokine content of the CM and showed that there was a higher concentration of monocyte chemoattractant protein-1 in renal preadipocyte-CM compared with the HAoSMC control (p<0.5). The addition of both renal preadipocyte- and epicardial adipocyte-CM resulted in the elevated production of vascular endothelial growth factor compared with the control HASoSMC CM (p<0.001). The adiponectin content in renal adipocyte-CM was increased compared to all the remaining adipocyte-CM (p<0.01). Moreover, the results showed a higher proliferation rate of HAoSMCs after co-culture with epicardial adipocyte-CM compared to the HAoSMC control (p<0.05). These results suggest that bioactive substances produced by adipocytes have a stimulatory effect on the proliferation of VSMCs., J. Ždychová, S. Čejsková, I. Králová Lesná, A. Králová, J. Malušková, L. Janoušek, L. Kazdová., and Obsahuje bibliografii
On the basis of laboratory and industrial experiments it was found that rubber can be treated by co-gasification with brown coal, namely in the process of the oxygen-steam pressure gasification in a moving bed (Lurgi gasification process). Considering the very low reactivity of the residual char from rubber, the optimal content of the rubber particles in the mixture being gasified should probably not exceed 10 wt.-%, but short-term increases in the proportion of these particles (up to 20 wt.-%) will not cause technological problems or significant economic losses., Pavel Straka, Vlastimil Kříž and Zdeněk Bučko., and Obsahuje bibliografii
Seasonal variations in a population of the monogenean Ancyrocephalus mogurndae Gussev, 1955 were investigated on gills of cage-cultured mandarin fish, Siniperca chuatsi (Basilewsky), during the period from April 1994 to April 1995. The abundance of A. mogurndae peaked in late spring and summer. Prevalence was high (75-100 %) throughout the study period, and did not vary significantly between months. More than 50 % of all monogeneans were found on the first and second gill arches, except one occasion when the fourth gill arch had the majority in April 1995. The niche breadths were significantly correlated with the population abundance. A coexistent parasitic myxosporean, Henneguya weishanensis Hu, 1965, on the gills of the fish was found to have little influence on the gill-arch preference of the monogenean, although the monogenean abundance was higher in those fish infected with the myxosporean.
In herbivorous insects, differences in the degree of specialization to host plants emerge when the distribution of an herbivore differs from that of its host plants, which results in a mosaic of populations differing in performance on the different host plants. Using a specialized butterfly, Battus polydamas archidamas Boisduval, 1936, which feeds exclusively on the genus Aristolochia, we test whether host plant co-occurrence and associated differences in host quality modify local adaptation in terms of larval preference and performance. We compared individuals from a monospecific host stand of Aristolochia chilensis with those from a mixed host stand of A. chilensis and A. bridgesii. Individuals were reared in a reciprocal transfer experiment in which source population and the host species fed to larvae were fully crossed in a two-by-two factorial experiment in order to quantify their preference, performance (development time, size and growth rate) and survival. Individuals from both populations preferred the species they ate during their larval development over the other host, which indicates host plant-induced preference with non-adaptive implications. Larvae from mixed and monospecific stands grew faster and survived better when reared on A. bridgesii than A. chilensis. Larvae from a monospecific host stand grew slower and fewer individuals survived under the same local conditions, which is contrary to expectations. Therefore, rearing the butterfly on A. bridgesii consistently resulted in better performance, which indicates that the monospecific population is less well adapted to its host than the mixed population. Variation in the occurrence of the two host plants in the two populations can result in divergent selection due to the variation in plant quality, which in this case could result in opposing adaptive processes., Rodrigo S. Rios, Cristian Salgado-Luarte, Gisela C. Stotz, Ernesto Gianoli., and Obsahuje bibliografii
For a finitely generated group, we study the relations between its rank, the maximal rank of its free quotient, called co-rank (inner rank, cut number), and the maximal rank of its free abelian quotient, called the Betti number. We show that any combination of the group’s rank, co-rank, and Betti number within obvious constraints is realized for some finitely presented group (for Betti number equal to rank, the group can be chosen torsion-free). In addition, we show that the Betti number is additive with respect to the free product and the direct product of groups. Our results are important for the theory of foliations and for manifold topology, where the corresponding notions are related with the cut-number (or genus) and the isotropy index of the manifold, as well as with the operations of connected sum and direct product of manifolds., Irina Gelbukh., and Obsahuje seznam literatury
Under a moderate water stress (pod water potential, Ψ№, - 1.5 MPa), induced by stopping irrigation for 3 d, the net photosynthetic rate (PN) decreased to 50 %, transpiration rate (£) to 85 %, stomatal conductance to 65 % and chlorophyll (Chi) content to 82 %, while the activities of photosystems (PS) and of some enzymes of the photosynthetic carbon reduction cycle (NAD- and NADP-glyceraldehyde-3-P dehydrogenases, aldolase) were almost without changes. The exceptions were ribulose-5-P kinase and 3-phosphoglycerate kinase, the activities of which were reduced to 55 and 79 %, respectively. Under a severe water stress (5 d without irrigation, VPW -2.1 MPa) all the above characteristics were strongly reduced (PN to 0.5 %, E to 57 %, PS1 to 62 %, PS2 to 37 %, enzyme activities to 48-68 %), but after rehydration the initial activities were restored. The reduction of PN in pods at a moderate water stress is probably related to the decline in activities of 3-phosphoglycerate kinase and ribulose-5-P kinase, while under a severe stress, when PN is lowered almost to zero, the decline in gs and electron transport activities is very important.
Activity of carbonic anhydrase (CA) was studied in wild type (WT) Chlamydomonas reinhardtii and five mutants distinguished only by retaining photosystem 1 (PS 1), photosystem 2 (PS 2), light-harvesting complexes (LHC) of PS 1 or PS 2 and both photosystems without LHC. Two forms of CA, soluble CA (sCA) and membrane- bound (mbCA), were found in the cells. The highest activity of mbCA was obseiwed in mutants which retained both photosystems, oř only PS 1 and PS 2. The mutants deprived of photosystems but retaining LHC almost lacked mbCA. Thus, there was a correlation between the retention of mbCA and mutant abilities to perform the photosynthesis. Photosynthetic characteristics of the high CO2 requiring mutant of C. reinhardtii CIA-3 were compared with those of WT grown at 2 % CO2 and after various times of exposure to limiting CO2 concentration (0.03 %). CIA-3 cells háve a lower photosynthetic affmity for inorganic carbon (Cj) as compared to WT when grown at high and low CO2 concentrations. Only in the WT cells the photosynthetic affmity for Cj was increased when the gas phase was changed to air. In CIA-3 the photosynthesis was inhibited by a high concentration of Cj.
The nullity of a graph G is the multiplicity of zero as an eigenvalue in the spectrum of its adjacency matrix. From the interlacing theorem, derived from Cauchy’s inequalities for matrices, a vertex of a graph can be a core vertex if, on deleting the vertex, the nullity decreases, or a Fiedler vertex, otherwise. We adopt a graph theoretical approach to determine conditions required for the identification of a pair of prescribed types of root vertices of two graphs to form a cut-vertex of unique type in the coalescence. Moreover, the nullity of subgraphs obtained by perturbations of the coalescence G is determined relative to the nullity of G. This has direct applications in spectral graph theory as well as in the construction of certain ipso-connected nano-molecular insulators., Didar A. Ali, John Baptist Gauci, Irene Sciriha, Khidir R. Sharaf., and Obsahuje seznam literatury