Adult female crabs (Neohelice granulata) were treated during the post-reproductive period with both 17-hydroxyprogesterone (17PG) and methyl farnesoate (MF). During the 4-week in vivo assay, animals were fed hormone-enriched (17PG or MF) pellets twice a week, at a dose of 2 nmol/g of body weight. Additionally, at the middle of the in vivo experiment, ovarian explants were incubated in vitro with each hormone at a concentration of 15 μM for 24 h. At the end of the in vivo assay, both the gonadosomatic index and the vitellogenic protein content (Vg) of crabs treated with either 17PG or MF were significantly higher (p < 0.05) than the values of the concurrent controls. In addition, the hemolymphatic vitellogenin level of both hormonally treated groups was higher. At the end of the in vitro assay, ovary explants incubated with 17PG had a significantly higher (p < 0.05) protein synthesis and content of Vg proteins than controls. Ovary explants incubated with MF had similar levels to controls (p > 0.05). The involvement of these hormones in the regulation of ovarian growth during the reproductive cycle of N. granulata is discussed. 相似文献
Many types of macroalgae contain a wide range of bioactive compounds that have antioxidant potential. However, in contrast to terrestrial plants, only a few studies have reported the antioxidant activity of seaweeds. Therefore, extracts from 26 marine macroalgae species from the south and southeast coasts of Brazil were evaluated for their antioxidant activity, using the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) method and β-carotene/linoleic acid assay, and their total phenolic contents, through Folin–Ciocalteu method. Padina gymnospora, Sargassum vulgare, and Osmundaria obtusiloba presented the highest values of total phenolic content. Using β-carotene bleaching assay, Colpomenia sinuosa, Dictyota sp., Dichotomaria marginata, Ganonema farinosum, and Spyridia clavata presented up to 65 % of antioxidant activity. Some of the extracts showed more than 60 % of inhibition of DPPH in the lowest concentration (0.01 mg/mL), including Amansia sp., Bostrychia tenella, Cryptonemia seminervis, Hypnea musciformis, Plocamium brasiliense (1), and S. clavata. Both Amansia sp., and C. seminervis presented the most relevant antioxidant potential, with percentage of inhibition greater than 70 % in the three tested concentrations. These two species were then analyzed by nuclear magnetic resonance spectroscopy (NMR) and were selected for guided fractionation bioassay. They both presented lipid compounds, fatty acids, esters of fatty acids, triglycerides, and sterols as major components. The fractionation of extracts revealed that the organic fractions were responsible for the antioxidant activity. The results obtained through this work indicate that the analyzed seaweeds are a promising source of compounds with high antioxidant potential. 相似文献
Zaprionus indianus is a drosophilid native to the Afrotropical region that has colonized South America and exhibits a wide geographical distribution. In contrast, Z. sepsoides is restricted to certain African regions. The two species differ in the size of their testes, which are larger in Z. indianus than in Z. sepsoides. To better understand the biology and the degree of differentiation of these species, the current study evaluated spermatogenesis in males of different ages by conventional staining techniques and ultrastructural analysis. Spermatogenesis and the ultrastructure of spermatozoa were similar in the two species, and the diploid number was confirmed to be 2n = 12. A greater number of spermatozoa were observed in young Z. indianus (1–3 days old) compared to Z. sepsoides males, which showed a higher frequency of cells at the early stages of spermatogenesis. The head of the sperm was strongly marked by silver staining, lacto-acetic orcein and the Feulgen reaction; the P.A.S. reaction revealed glycogen granules in the testes of both species. Both species presented similar arrangement of microtubules (9+9+2), two mitochondrial derivatives of different size and 64 spermatozoa per bundle. Such similarity within the genus Zaprionus with other species of Drosophila, indicates that these structures are conserved in the family Drosophilidae. The differences observed the number and frequency of sperm cells in the early stages of spermatogenesis, between the young males of Z. indianus and Z. sepsoides, are features that may interfere with reproductive success and be related to the invasive potential of Z. indianus. 相似文献
Nitric oxide (NO) is an important chemical compound involved in many physiological and pathological processes in living organisms. However, nitric oxide is a very reactive radical that needs to be carried through organisms to reach the desired biological target. With the aim of developing new compounds that can be used as biomedical NO carrier agents we carried out a theoretical investigation at B3LYP/6-31?+?G(d)/LANL2DZ level on the interaction of NO with RuTAP (Ruthenium tetraazaporphyrin) and Ru(L)TAP, where L?=?Clˉ, NH3, and Pyridine (Py)) and the oxidation state of Ru ranging from +1 to +3. The theoretical calculation results show that the geometric and electronic parameters of the Ru–NO bond are highly dependent on the oxidation state of Ru and of the chemical nature of ligand L at axial position. The results also show clearly that RuTAP and Ru(L)TAP are good potential candidates to be used as NO carriers in living organisms. 相似文献
Electron micrographs revealed the presence of gap junctions in osteoblastic cells over 40 years ago. These intercellular channels formed from connexins are present in bone forming osteoblasts, bone resorbing osteoclasts, and osteocytes (mature osteoblasts embedded in the mineralized bone matrix). More recently, genetic and pharmacologic studies revealed the role of connexins, and in particular Cx43, in the differentiation and function of all bone types. Furthermore, mutations in the gene encoding Cx43 were found to be causally linked to oculodentodigital dysplasia, a condition that results in an abnormal skeleton. Pannexins, molecules with similar structure and single-membrane channel forming potential as connexins when organized as hemichannels, are also expressed in osteoblastic cells. The function of pannexins in bone and cartilage is beginning to be uncovered, but more research is needed to determine the role of pannexins in bone development, adult bone mass and skeletal homeostasis. We describe here the current knowledge on the role of connexins and pannexins on skeletal health and disease.
Glucagon, growth hormone and cortisol responses to insulin-induced hypoglycemia have been studied in nine normal subjects and four patients with orthostatic hypotension who also had markedly deficient sympathoadrenal medullary responses. Absence of catecholamine responses to hypoglycemia does not prevent the other hormonal responses. Glucagon, growth hormone and cortisol secretion appear to be evoked independently from the catecholamine response during hypoglycemia. Elevated basal cortisol levels are the probable cause of a delay in the nadir of hypoglycemia observed in patients with adrenergic insufficiency. The sympathetic nervous system dysfunction in patients with neurogenic orthostatic hypotension may include deficient adrenal medullary responses although other counterregulatory responses remain functional. 相似文献