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排序方式: 共有303条查询结果,搜索用时 78 毫秒
1.
Excessive intake of essential elements agitates elemental homeostasis resulting in their heterogeneous distribution. Distraction
of these elements in central nervous system (CNS) have been demonstrated in many neurological disorders, which are vital in
generating free radicals, causing oxidative stress, and contributing to neuronal maladies. The developing CNS is highly vulnerable
to environmental agents, including fluoride. Fluorosis is one such disorder ensued from excessive consumption of fluoride
containing water and/or foods that poses a greater threat to the life. Present study offers perturbations caused by fluoride
toxicity on the level of biometal and antioxidant homeostasis and their interactions. Pregnant Wistar rats were exposed to
100- and 200-ppm fluoride (F−) in drinking water and controls with tap water. The pups born to them were used for the study. On 21st postnatal day, the
concentration of fluoride, biometals, and oxidative stress markers were determined in discrete regions of CNS. The levels
of fluoride, copper, and iron increased whereas manganese and zinc were decreased considerably. Among antioxidant enzymes,
catalase, superoxide dismutase, and glutathione peroxidase were decreased and lipid peroxidation was increased with regional
alterations. The correlation coefficient values among oxidative stress markers and biometals were either positive or negative
and showed less significance during correlation. The results confirm that the fluoride provoked oxidative stress and biometal
deformations are synergistic that successively governs the neuronal damage and developing CNS no longer prevents exacerbations
of fluoride. 相似文献
2.
Photosynthesis Research - Two-dimensional electronic spectra (2DES) provide unique ways to track the energy transfer dynamics in light-harvesting complexes. The interpretation of the peaks and... 相似文献
3.
Jeremiah G. Plass-Johnson Marc H. Taylor Aidah A. A. Husain Mirta C. Teichberg Sebastian C. A. Ferse 《PloS one》2016,11(4)
Changes in the coral reef complex can affect predator-prey relationships, resource availability and niche utilisation in the associated fish community, which may be reflected in decreased stability of the functional traits present in a community. This is because particular traits may be favoured by a changing environment, or by habitat degradation. Furthermore, other traits can be selected against because degradation can relax the association between fishes and benthic habitat. We characterised six important ecological traits for fish species occurring at seven sites across a disturbed coral reef archipelago in Indonesia, where reefs have been exposed to eutrophication and destructive fishing practices for decades. Functional diversity was assessed using two complementary indices (FRic and RaoQ) and correlated to important environmental factors (live coral cover and rugosity, representing local reef health, and distance from shore, representing a cross-shelf environmental gradient). Indices were examined for both a change in their mean, as well as temporal (short-term; hours) and spatial (cross-shelf) variability, to assess whether fish-habitat association became relaxed along with habitat degradation. Furthermore, variability in individual traits was examined to identify the traits that are most affected by habitat change. Increases in the general reef health indicators, live coral cover and rugosity (correlated with distance from the mainland), were associated with decreases in the variability of functional diversity and with community-level changes in the abundance of several traits (notably home range size, maximum length, microalgae, detritus and small invertebrate feeding and reproductive turnover). A decrease in coral cover increased variability of RaoQ while rugosity and distance both inversely affected variability of FRic; however, averages for these indices did not reveal patterns associated with the environment. These results suggest that increased degradation of coral reefs is associated with increased variability in fish community functional composition resulting from selective impacts on specific traits, thereby affecting the functional response of these communities to increasing perturbations. 相似文献
4.
Ocellatin‐PT antimicrobial peptides: High‐resolution microscopy studies in antileishmania models and interactions with mimetic membrane systems
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Mayara Oliveira Ana Georgina Gomes‐Alves Carla Sousa Mariela Mirta Marani Alexandra Plácido Nuno Vale Cristina Delerue‐Matos Paula Gameiro Selma A. S. Kückelhaus Ana M. Tomas José Roberto S. A. Leite Peter Eaton 《Biopolymers》2016,105(12):873-886
Although the mechanism of action of antimicrobial peptides (AMPs) is not clear, they can interact electrostatically with the cell membranes of microorganisms. New ocellatin‐PT peptides were recently isolated from the skin secretion of Leptodactylus pustulatus. The secondary structure of these AMPs and their effect on Leishmania infantum cells, and on different lipid surface models was characterized in this work. The results showed that all ocellatin‐PT peptides have an α‐helix structure and five of them (PT3, PT4, PT6 to PT8) have leishmanicidal activity; PT1 and PT2 affected the cellular morphology of the parasites and showed greater affinity for leishmania and bacteria‐mimicking lipid membranes than for those of mammals. The results show selectivity of ocellatin‐PTs to the membranes of microorganisms and the applicability of biophysical methods to clarify the interaction of AMPs with cell membranes. 相似文献
5.
Al‐Sayed Al‐Soudy Tsuyoshi Nakanishi Seiya Mizuno Yoshikazu Hasegawa Hossam H. Shawki Megumi C. Katoh Walaa A. Basha Abdelaziz E. Ibrahim Hany A. El‐Shemy Hiroyoshi Iseki Atsushi Yoshiki Youhei Hiromori Hisamitsu Nagase Satoru Takahashi Hisashi Oishi Fumihiro Sugiyama 《Genesis (New York, N.Y. : 2000)》2016,54(7):389-397
Spermatogenesis is a complex and highly regulated process by which spermatogonial stem cells differentiate into spermatozoa. To better understand the molecular mechanisms of the process, the Cre/loxP system has been widely utilized for conditional gene knockout in mice. In this study, we generated a transgenic mouse line that expresses Cre recombinase under the control of the 2.5 kbp of the Prolactin family 3, subfamily b, member 1 (Prl3b1) gene promoter (Prl3b1‐cre). Prl3b1 was initially reported to code for placental lactogen 2 (PL‐2) protein in placenta along with increased expression toward the end of pregnancy. PL‐2 was found to be expressed in germ cells in the testis, especially in spermatocytes. To analyze the specificity and efficiency of Cre recombinase activity in Prl3b1‐cre mice, the mice were mated with reporter R26GRR mice, which express GFP ubiquitously before and tdsRed exclusively after Cre recombination. The systemic examination of Prl3b1‐cre;R26GRR mice revealed that tdsRed‐positive cells were detected only in the testis and epididymis. Fluorescence imaging of Prl3b1‐cre;R26GRR testes suggested that Cre‐mediated recombination took place in the germ cells with approximately 74% efficiency determined by in vitro fertilization. In conclusion, our results suggest that the Prl3b1‐cre mice line provides a unique resource to understand testicular germ‐cell development. genesis 54:389–397, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
6.
Methyl parathion induced alterations in the level of monoamines, viz. norepinephrine, dopamine and serotonin were studied in discrete regions of developing central nervous system of rat pups. A significant decrease in the level of monoamines noticed in methyl parathion toxicosis may be related to the altered neuronal activity and inefficiency, leading to depression and impairment in various behavioural activities. In contrast to AChE inhibition, monoamine oxidase (MAO) activity showed an increasing trend and it could cause deamination of catecholamines and accumulation of its metabolites. This suggests that an increased AChE inhibition may indirectly stimulate MAO activity in developing rat pups exposed to methyl parathion. 相似文献
7.
Stimulation of voltage-dependent calcium channels during capacitation and by progesterone in human sperm 总被引:3,自引:0,他引:3
González-Martínez MT Bonilla-Hernández MA Guzmán-Grenfell AM 《Archives of biochemistry and biophysics》2002,408(2):205-210
To fertilize, mammalian sperm must undergo two sequential steps that require activation of calcium entry mechanisms, capacitation and acrosomal exocytosis, induced in the latter case by the egg zona pellucida glycoprotein ZP3 or by progesterone. Voltage-dependent calcium channels (VDCC) could participate in these processes. Since patch clamp recordings are extremely difficult in mature sperm, the activity of VDCC has been alternatively analyzed with optical detectors of membrane potential and intracellular calcium in sperm populations. Using this approach, we previously reported that in human sperm there is a voltage-dependent calcium influx system that strongly indicates that human sperm are endowed with functional VDCC. In this study we developed evidence indicating that calcium influx through VDCC is significantly stimulated during sperm in vitro capacitation and by progesterone action, which is present in the follicular fluid that surrounds the egg. The observed effects of capacitation and progesterone on VDCC may be physiologically significant for sperm-egg interaction. 相似文献
8.
García Arocena D de Diego Y Oostra BA Willemsen R Mirta Rodriguez M 《Human genetics》2000,106(3):366-369
Fragile X syndrome is the most common cause of hereditary mental retardation. The FMR1 gene, which is involved in fragile X syndrome, contains a polymorphic CGG repeat, which expands in affected patients. Expanding triplet repeats have been shown to be a new type of mutation, termed "dynamic mutation", responsible for more than 12 genetic diseases. These mutations occur as multiple steps rather than as a single event. The first step leads to an unstable allele that then becomes increasingly unstable generally achieving further increases in copy or occasionally contraction. In this report, we describe a fragile X boy with both a hypermethylated full mutation and a deletion of 905 bp encompassing the CGG repeat. The upstream breakpoint is 438 bp 5' to the CGG repeat and the downstream breakpoint is 420 bp 3' of the triplet repeats. The deletion includes the ATG starting codon for translation of the FMR1 gene. This was confirmed by using FMRP immunocytochemistry both on blood smears and hair roots. The deleted region is flanked by a ccgg direct repeat next to the breakpoints; this may have had a critical role in the formation of a secondary DNA structure leading to the deletion. 相似文献
9.
10.
Mirta Alicia Flamini Claudio Gustavo Barbeito Eduardo Juan Gimeno Enrique Leo Portiansky 《Acta zoologica》2009,90(4):390-400
Lagostomus maximus is a South American Hystricognathi rodent whose reproductive behaviour shows characteristics unusual for mammals, such as polyovulation (200–800 oocytes) and a high rate of embryo mortality. Thirty‐six mature females captured in the province of Buenos Aires showed different physiological reproductive stages. Most of them presented a postpartum oestrus in August–September. This characteristic is different from that reported in other geographical areas. The stages considered were: anoestrus, follicular phase, early pregnancy and late pregnancy. The ovaries were light‐pink and smooth and presented a tortuous cord‐like aspect. Many primordial follicles were found in all the females studied. Follicles in different states of maturation and primary and accessory corpora lutea were observed in the cortex. These structures were smaller than those present in other related species. Follicles did not project into the surface of the organ. Calcified follicles of diverse size were found in all the ovaries. Atretic follicles were found in all the stages analysed. Interstitial tissue surrounding the follicles and the corpora lutea was also observed. The number and proportion of different cortical structures varied in the physiological stages analysed. The ovaries of the viscacha have differential characteristics in comparison to other Hystricognathi, some of them related to polyovulation. 相似文献