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41.
Gestodene acidic treatment afforded a single rearrangement product, namely 13-beta-ethyl-18,19-dinorpregna-4,14,16-trien-3,20-dione 3, which was originated through HCl-catalyzed Rupe rearrangement. Drospirenone acidic treatment yielded two epimeric lactones by addition of HCl to the 6beta,7beta-cyclopropane ring, namely 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17beta-pregn-4-ene-21,17-carbolactone 4 and 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17alpha-pregn-4-ene-21,17-carbolactone 5. The structure of the compounds was assessed by spectroscopic and crystallographic methods.  相似文献   
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Abstract

Megagametophytes of Macrozamia communis were incubated in White's Basal Medium and in White's Basal Medium modified with 2,4-D and kinetin. On the medium enriched with growth substances, regeneration of coralloid roots was induced. These are morphologically identical to sporophytic coralloid roots, without any endosymbiont and displaying negative geotropism. These results confirm the fact that coralloid roots represent an inherent feature of the root system of the Cycadales rather than being the result of induction by microbial factors. Therefore it is possible to suggest that coralloid roots represent vestigial pneumatophores.  相似文献   
44.
The key step in the first chemical synthesis of anthrose (16) and its methyl alpha- (6) and beta-glycoside (22) was inversion of configuration at C-2 in triflates 10, 2, and 18, respectively, obtained from the common intermediate, methyl 4-azido-3-O-benzyl-4,6-dideoxy-alpha-D-mannopyranoside (1). To prepare methyl alpha-anthroside (6), methylation at O-2 of the gluco product 3, obtained from 2, was followed by hydrogenation/hydrogenolysis of the formed 2-methyl ether 4, to simultaneously remove the protecting benzyl group and reduce the azido function. Subsequent N-acylation of the formed amine 5 with 3-hydroxy-3-methylbutyric acid gave the target methyl alpha-glycoside 6. Synthesis of methyl beta-anthroside (22) comprised the same sequence of reactions, starting from the known methyl 4-azido-3-O-benzyl-4,6-dideoxy-beta-D-mannopyranoside (17), which was prepared from 1. In the synthesis of anthrose (16), 1-thio-beta-glucoside 11, obtained from 1 through 10, was methylated at O-2, and the azido function in the resulting benzylated 1-thioglycoside 12 was selectively reduced to give amine 13. After N-acylation with 3-hydroxy-3-methylbutyric acid, 1-thioglycoside 14 was hydrolyzed to give the corresponding reducing sugar, aldol 15, which was debenzylated to afford anthrose.  相似文献   
45.
Exercise training has been used for treatment/prevention of many cardiovascular diseases, but the mechanisms need to be clarified. Thus, our aim was to compare oxidative stress parameters between rats submitted to a swimming training and sedentary rats (control). Twelve male rats were divided into two groups: control and exercise training. The exercise training had daily 1 h swimming sessions for 8 weeks and a load (5% of its body mass) was placed in rat's tail. Thereafter the animals were killed, aorta and heart were surgically removed and blood was collected. Body mass gain, thiobarbituric acid reactive species (TBARS), carbonyl content, total reactive antioxidant potential (TRAP), total antioxidant reactivity (TAR), superoxide dismutase (SOD) activity and catalase (CAT) activity were evaluted. The trained rats showed a lower body mass gain and no modifications on heart. An increased SOD activity was observed on aorta after the training, but no changes were seen for CAT activity, which led to an increased SOD/CAT ratio. The arterial TBARS was also increased for trained rats. The decrease in TRAP in exercise training was the single modification on plasma. Our findings suggest that the increased SOD activity could play a role in vascular adaptations to exercise training. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
46.
This work presents a new clock reaction based on ozone, iodine, and chlorate that differs from the known chlorate-iodine clock reaction because it does not require UV light. The induction period for this new clock reaction depends inversely on the initial concentrations of ozone, chlorate, and perchloric acid but is independent of the initial iodine concentration. The proposed mechanism considers the reaction of ozone and iodide to form HOI, which is a key species for producing non-linear autocatalytic behavior. The novelty of this system lies in the presence of ozone, whose participation has never been observed in complex systems such as clock or oscillating reactions. Thus, the autocatalysis demonstrated in this new clock reaction should open the possibility for a new family of oscillating reactions.  相似文献   
47.
The sporogony of Hepatozoon caimani has been studied, by light microscopy, in the mosquito Culex fatigans fed on specimens of the caiman Caiman c. crocodilus showing gametocytes in their peripheral blood. Sporonts iniciate development in the space between the epithelium of the insect gut and the elastic membrane covering the haemocoele surface of the stomach. Sporulating oocysts are clustered on the gut, still invested by the gut surface membrane. Fully mature oocysts were first seen 21 days after the blood-meal. No sporogonic stages were found in some unidentified leeches fed on an infected caiman, up to 30 days following the blood-meal. When mosquitoes containing mature oocysts were fed to frogs (Leptodactylus fuscus and Rana catesbeiana), cysts containing cystozoites developed in the internal organs, principally the liver. Feeding these frogs to farm-bred caimans resulted in the appearance of gametocytes in their peripheral blood at some time between 59 and 79 days later, and the development of tissue cysts in the liver, spleen, lungs and kidneys. Transmission of the parasite was also obtained by feeding young caimans with infected mosquitoes and it is suggested that both methods occur in nature. The finding of similar cysts containing cystozoites in the semi-aquatic lizard Neusticurus bicarinatus, experimentally fed with infected C. fatigans, suggests that other secondary hosts may be involved.  相似文献   
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49.
Parodon and Apareiodon lack sufficiently consistent morphological traits to be considered a monophyletic group in Parodontidae. Species within this family are either sex-homomorphic or sex-heteromorphic (i.e., lacking a differentiated sex chromosome system, ZZ/ZW or ZZ/ZW(1)W(2)). In this study, a DNA fragment from the heterochromatin segment of the W chromosome of Apareiodon ibitiensis (named WAp) was microdissected and used for in situ mapping of nine Parodontidae species. The species were also characterized using a satellite DNA probe (pPh2004). The species were phylogenetically clustered according to 17 characters, which were examined by both classical and molecular cytogenetic techniques. Given the present results, the single ZZ/ZW sex chromosome system seems to have been derived from a paracentric inversion of a terminal WAp site onto the proximal regions of the short arms of a metacentric chromosome pair, followed by WAp site amplification. We reason that these events restrained recombination and favored differentiation of the W chromosome in some species. Moreover, co-hybridization experiments targeting the WAp and pPh2004 repetitive DNA sites of A. affinis suggest that the ZZ/ZW(1)W(2) sex chromosomes of this species may have arisen from a translocation between the proto-sex chromosome and an autosome. Our phylogenetic analysis corroborates the hypothesis of sex chromosome differentiation and establishes groups of closely related species. The phylogenetic reorganization in response to these new data supports the presence of internal monophyletic groups within Parodontidae.  相似文献   
50.
This article describes the phytochemical study of Cannabis sativa roots from northeastern Brazil. The dried plant material was pulverized and subjected to exhaustive maceration with ethanol at room temperature, obtaining the crude ethanolic extract (Cs-EEBR). The volatile compounds were analyzed by gas chromatography coupled with mass spectrometry (GC/MS), which allowed to identify 22 compounds by comparing the linear retention index (LRI), the similarity index (SI) and the fragmentation pattern of the constituents with the literature. By this technique the major compounds identified were: friedelan-3-one and β-sitosterol. In addition, two fractions were obtained from Cs-EEBR by classical column chromatography and preparative thin layer chromatography. These fractions were analyzed by NMR and IR and together with the mass spectrometry data allowed to identify the compounds: epifriedelanol, friedelan-3-one, β-sitosterol and stigmasterol. The study contributed to the phytochemical knowledge of Cannabis sativa, specifically the roots, as there are few reports on the chemical constituents of this part of the plant.  相似文献   
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