Hypolipidemic and antiatherosclerotic potential of Pleurotus ostreatus, cultived by submerged fermentation in the high-fat diet fed rats

The ability of Pleurotus ostreatus biomass, cultived by submerged fermentation, to produce beneficial effect on lipid profile and macrophages activity during a high-fat diet (HFD) for a long-term intake was investigated. Blood samples were collected through cardiac puncture to measure the plasma cholesterol, triglycerides, low-density protein (LDL), high-density protein (HDL), aspartate aminotransferase (AST) activity, urea-blood urea nitrogen (BUN)/creatinine ratio of rats fed on an HFD for 4 months. Dosage of lipid hydroperoxides was carried out on methanolic extract of liver tissue. Peritoneal macrophages activity was evaluated in relation to the superoxide anion, hydrogen peroxide and nitric oxide production, phagocytosis and lysosomal volume. The administration of P. ostreatus significantly altered the lipid profile and oxidative stress as related to the LDL and triglycerides decrease and inhibitory effects on superoxide anion and hydrogen peroxide production. All findings of this study lead us to suggest that the P. ostreatus maybe a beneficial agent in the hyperlipidemia and atherosclerosis treatments.     

Biochemical characterization of recombinant guaA-encoded guanosine monophosphate synthetase (EC 6.3.5.2) from Mycobacterium tuberculosis H37Rv strain

Administration of the current tuberculosis (TB) vaccine to newborns is not a reliable route for preventing TB in adults. The conversion of XMP to GMP is catalyzed by guaA-encoded GMP synthetase (GMPS), and deletions in the Shiguella flexneri guaBA operon led to an attenuated auxotrophic strain. Here we present the cloning, expression, and purification of recombinant guaA-encoded GMPS from Mycobacterium tuberculosis (MtGMPS). Mass spectrometry data, oligomeric state determination, steady-state kinetics, isothermal titration calorimetry (ITC), and multiple sequence alignment are also presented. The homodimeric MtGMPS catalyzes the conversion of XMP, MgATP, and glutamine into GMP, ADP, PP(i), and glutamate. XMP, NH(4)(+), and Mg(2+) displayed positive homotropic cooperativity, whereas ATP and glutamine displayed hyperbolic saturation curves. The activity of ATP pyrophosphatase domain is independent of glutamine amidotransferase domain, whereas the latter cannot catalyze hydrolysis of glutamine to NH(3) and glutamate in the absence of substrates. ITC data suggest random order of binding of substrates, and PP(i) is the last product released. Sequence comparison analysis showed conservation of both Cys-His-Glu catalytic triad of N-terminal Class I amidotransferase and of amino acid residues of the P-loop of the N-type ATP pyrophosphatase family.     

Morphologic evaluation and expression of matrix metalloproteinases-2 and 9 and nitric oxide during experimental periodontal disease in rat

The immunopathologic and inflammatory mechanisms involved in periodontal disease (PD) include the participation of host resident, inflammatory cells and chemical mediators. Metalloproteinases (MMPs) and nitric oxide (NO) play essential role in extracellular matrix turnover of periodontal tissue destruction. In this study, by means of RT-PCR through semi-quantitative densitometric scanning methods, the expression of MMPs -2 and -9 and inducible NO synthase (iNOS) was temporally and spatially investigated during the destructive mechanisms of experimentally induced PD in rats. Samples from different periods were microscopically analyzed and compared with the contralateral side (control). Our results showed significant expression of MMP-9 and iNOS in tissues affected by PD, as compared with controls, three days after PD induction, simultaneously with the beginning of alveolar bone loss. At 7 days post induction, only the MMP-9 mRNA presented a significantly higher expression, as compared with the respective controls. Thus, in the rat ligature-induced PD, MMP-9 and iNOS might importantly participate in the early stages of the disease, including inflammatory cell migration, tissue destruction and alveolar bone resorption. Also, we may suggest that the exuberant presence of PMNs may be related to the important expression of iNOS and MMP-9 found at 3 days post induction.     

Preparation of a beef-extract as a laboratory reference material for the determination of heterocyclic amines

The present paper describes the preparation of a suitable laboratory reference material (LRM) to validate analytical methods for the determination of heterocyclic amines (HAs) in foods. Three different lots of reference material were prepared using a beef extract which was contaminated with a well-known quantity of amines at different levels ranging from 10 to 75 ng/g. These materials were then lyophilised under determined conditions and, after grinding and sieving, homogenised and, finally, bottled and labelled. Homogeneity and stability studies were performed and no statistical differences were observed in the analysis of variances for within- and between-bottle results, thus demonstrating the homogeneity of the material. Stability at different storage temperatures (-18, +4, +25 and +40 degrees C) and times (1, 2, 3 and 6 months) was also tested. Therefore, the material can be considered homogeneous and stable and can be proposed for use in inter-comparison exercises for the determination of HAs.     

Modulation of auxin signalling through DIAGETROPICA and ENTIRE differentially affects tomato plant growth via changes in photosynthetic and mitochondrial metabolism

Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher V_cmax and J_max coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes.     

A simple chromosomal marker can reliably distinguishes <Emphasis Type="Italic">Poncirus</Emphasis> from <Emphasis Type="Italic">Citrus</Emphasis> species

Several chromosome types have been recognized in Citrus and related genera by chromomycin A₃ (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA⁺ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm. During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars, two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin, we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker.     

Inhibitory effect of combinations of digoxin and endogenous cardiotonic steroids on Na+/K+-ATPase activity in human kidney membrane preparation

AimsCardiac glycosides have been extensively used in the treatment of congestive heart failure for more than 200 years. Recently, cardenolides and bufadienolides were isolated from mammalian tissue and are considered as a new class of steroidal hormones. The aim of the present work was to characterize the interaction between the most clinical used cardiac glycoside digoxin and the cardiac glycosides known to exist endogenously, i.e., ouabain, marinobufagin and telocinobufagin, on human kidney Na⁺/K⁺-ATPase.Main methodsInhibition of Na⁺/K⁺-ATPase activity from crude membrane preparations of human kidney was performed using increasing concentrations of the drugs alone or mixtures of ouabain:digoxin, telocinobufagin:digoxin and marinobufagin:digoxin in a fixed ratio 1:4, 2:3 and 3:2, respectively. The colorimetric method of Fiske and Subbarow was used to measure the inorganic phosphate released.Key findingsAnalyses of inhibition curves showed that the experimental curves for all combinations were superimposed on the theoretical additive curves indicating that an additive effect occurs among distinct cardenolides and bufadienolides combinations on the human α1β1 Na⁺/K⁺-ATPase protomer.SignificanceConsidering the extensive use of digoxin in the treatment of heart failure and the recent findings that endogenous cardiac glycosides may have altered levels in many diseases, including heart failure, the demonstration of additive effect between cardiac glycosides can help in the understanding of recent clinical observations, including that lower than usual doses of cardiac glycosides are necessary for decreasing mortality in these patients.     

Maternal-Fetal Distribution of Calcium,Iron, Copper,and Zinc in Pregnant Teenagers and Adults

Adolescence is marked by intensive growth and development. When pregnancy occurs during this period of the mother’s growth, there is an increase in her nutritional needs. The aim of this study was to determine the levels of calcium, iron, copper, and zinc in maternal plasma, the placenta, and in the cord plasma of pregnant teenagers and adults. A total of 80 sets of maternal plasma, placentas, and cord plasma (40 from teenagers and 40 from adults) were analyzed using synchrotron radiation total reflection X-ray fluorescence. The levels of calcium, copper, and zinc in the maternal and cord plasma from teenagers were not significantly different than those from adults. Iron levels in the teenagers maternal and cord plasma were higher than in the adults. All of the minerals analyzed were present at higher levels in the placentas from adults than those from teenagers. However, the low quantities of placental calcium, iron, copper, and zinc in the teenagers do not compromise the levels of these minerals in the cord plasma. Future research regarding the placental transport of these minerals is recommended to investigate the efficiency of mechanisms of transfer of these minerals in pregnant teenagers.     

Naturally occurring radionuclides in food and drinking water from a thorium-rich area

This paper focuses on a survey of uranium and thorium decay chain radionuclides in food and drinking water from the thorium-rich (monazite-bearing) region of Buena, which is located in the state of Rio de Janeiro, Brazil. The radionuclide concentration values in the food and drinking water from Buena reached values higher than 100-fold the international reference values. The daily intake of radionuclides by the local population is similar to that of another high background radiation area in Brazil, but the intake is higher than that of residents from a normal background radiation area. Approximately 58?% of the food consumed by Buena inhabitants is produced locally. Based on that figure, locally produced food and the dilution of total radionuclides in the diet of residents caused by food importation are both highly relevant to a population’s intake of radionuclides. The concentration values for ²¹⁰Pb and the radium isotopes in drinking water from Buena are among the highest values to be reported in the literature. ²²⁸Ra is the most important radionuclide ingested with both food and water among the inhabitants of Buena.     

Morphological and temporal variation in early embryogenesis contributes to species divergence in Malawi cichlid fishes

The cichlid fishes comprise the largest extant vertebrate family and are the quintessential example of rapid “explosive” adaptive radiations and phenotypic diversification. Despite low genetic divergence, East African cichlids harbor a spectacular intra- and interspecific morphological diversity, including the hyper-variable, neural crest (NC)-derived traits such as coloration and craniofacial skeleton. Although the genetic and developmental basis of these phenotypes has been investigated, understanding of when, and specifically how early, in ontogeny species-specific differences emerge, remains limited. Since adult traits often originate during embryonic development, the processes of embryogenesis could serve as a potential source of species-specific variation. Consequently, we designed a staging system by which we compare the features of embryogenesis between three Malawi cichlid species—Astatotilapia calliptera, Tropheops sp. ‘mauve’ and Rhamphochromis sp. “chilingali”—representing a wide spectrum of variation in pigmentation and craniofacial morphologies. Our results showed fundamental differences in multiple aspects of embryogenesis that could underlie interspecific divergence in adult adaptive traits. First, we identified variation in the somite number and signatures of temporal variation, or heterochrony, in the rates of somite formation. The heterochrony was also evident within and between species throughout ontogeny, up to the juvenile stages. Finally, the identified interspecific differences in the development of pigmentation and craniofacial cartilages, present at the earliest stages of their overt formation, provide compelling evidence that the species-specific trajectories begin divergence during early embryogenesis, potentially during somitogenesis and NC development. Altogether, our results expand our understanding of fundamental cichlid biology and provide new insights into the developmental origins of vertebrate morphological diversity.