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81.
Male pipefish prefer dominant over attractive females 总被引:5,自引:3,他引:2
Animals may obtain information guiding their choice betweenpotential partners from observing competitive interactionsand displays between them, or from displays directed at thechoosing individual. In the sex-role reversed pipefish Syngnathustyphle females display a temporary ornament (a color pattern)to other females as well as to males. We have previously shown
that display of female ornaments per se is attractive to males.Here we show that information from competitive displays canoverride such direct attraction displays as signals in thepartner choice process. In a mate choice experiment, an enclosedmale could choose between two females. On the first experimentalday, females could interact freely, while on the second daythey were isolated from each other. When female-female competitionwas allowed, the ornament display was directed more to theother female than to the male: Time competing, rather thantime courting the male, correlated with ornament display duration.However, ornament display under competition and ornament displayin the absence of competition did not correlate significantly.In fact, females competing more intensively on day one displayedthe ornament less on day two. Furthermore, the ornament displayduring the first, but not the second, day predicted male matechoice on the second day. Thus, males remembered previous informationfrom competitive displays and used it rather than immediateinformation from displays in the absence of female-female competition.We suggest that competitive displays more reliably signal female
quality as compared to noncompetitive ones, and that males benefitfrom mating with dominant females. 相似文献
82.
Jia Jeong Toshihiko Toida Yuki Muneta Ichiro Kosiishi Toshio Imanari Robert J. Linhardt Hyung Seok Choi Song Ji Wu Yeong Shik Kim 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2001,130(4)
Acharan sulfate is a glycosaminoglycan (GAG), having the structure →4)-2-acetamido-2-deoxy-α-
-glucopyranose(1→4)-2-sulfo-α-
-idopyranosyluronic acid (1→, isolated from the body of the giant African snail Achatina fulica. This GAG represents 3–5% of the dry weight of this snail's soft body tissues. Frozen sections and polyester wax sections of the snail's body were stained by Alcian blue-periodic acid-Schiff's reagent (PAS) to localize acharan sulfate. Alcian blue staining indicated that GAG was mainly secreted into the outer surface of the body from internal granules. A highly mucous material was collected and treated and the acharan sulfate was recovered by ethanol and cetyl pyridinium chloride precipitation. Crude acharan sulfate was purified by DEAE-Sephacel ion-exchange chromatography. Depolymerization of intact mucus and purified acharan sulfate fractions by heparin lyase II (heparitinase I) from Flavobacterium heparinum produced an unsaturated disaccharide as a major product, establishing the repeating unit of acharan sulfate. These results demonstrate that mucus in the granule and secreted to the outside of the body is composed entirely of acharan sulfate. 相似文献
83.
Paul Linhardt 《Biodegradation》1997,8(3):201-210
Case histories and proposed mechanisms formicrobiologically influenced corrosion of metals andalloys by metal depositing microorganisms arereviewed. Mechanisms with indirect participation ofthese microorganisms, usually iron- and manganeseoxidizing species, are distinguished from anothermechanism which accounts specifically for theelectrochemical properties of deposits containingoxides and hydroxides of Mn in higher oxidationstates. The possible influence of such deposits whichwere formed microbiologically is evaluated. Theevaluation is based on the principles ofelectrochemical corrosion of metals and on theelectrochemical properties of Mn3+/4+- compounds.After briefly reviewing the microbiologicalMn-oxidation, experimental evidence for the predictedcorrosion by such deposits is provided and a model formicrobiologically influenced corrosion by manganeseoxidizing microorganisms is proposed for stainlesssteel. Possible consequences of the model andpractical aspects of such a corrosion are discussed. 相似文献
84.
Gunilla Lindmark Stig Melander Bo A. Nilsson Göran Zador 《Prostaglandins & other lipid mediators》1973,3(4):481-489
As a consequence of great individual variations among pregnant women in their response to prostaglandin medication, overstimulation of the uterus might occasionally occur. The need of a drug which could safely prevent excessive and undesirable prostaglandin-induced uterine contractions is therefore apparent.Two β-mimetic adrenergic compounds, orciprenaline and ritodrine, were tested with respect to their ability to reduce prostaglandin-induced uterine activity. Both compounds have successfully depressed the intensity, as well as the frequency of uterine contractions, which were previously induced by intrauterine administration of prostaglandin F2α. With both drugs the reduction in uterine activity was closely dose-related and accompanied by a considerable increase in the maternal heart rate. While orciprenaline did not alter the maternal blood pressure, ritodrine produced a rise in systolic, and a fall in diastolic pressure. No other side effect was recorded. When the infusion ceased, uterine activity increased in various degrees.On the basis of the present findings the possible role of prostaglandins in the physiological regulation of the uterine contractions during pregnancy is discussed. 相似文献
85.
Species identification can be interesting in a wide range of areas, for example, in forensic applications, food monitoring and in archeology. The vast majority of existing DNA typing methods developed for species determination, mainly focuses on a single species source. There are, however, many instances where all species from mixed sources need to be determined, even when the species in minority constitutes less than 1 % of the sample. The introduction of next generation sequencing opens new possibilities for such challenging samples. In this study we present a universal deep sequencing method using 454 GS Junior sequencing of a target on the mitochondrial gene 16S rRNA. The method was designed through phylogenetic analyses of DNA reference sequences from more than 300 mammal species. Experiments were performed on artificial species-species mixture samples in order to verify the method’s robustness and its ability to detect all species within a mixture. The method was also tested on samples from authentic forensic casework. The results showed to be promising, discriminating over 99.9 % of mammal species and the ability to detect multiple donors within a mixture and also to detect minor components as low as 1 % of a mixed sample. 相似文献
86.
Ingegerd A. Mejàre Gunilla Klingberg Frida K. Mowafi Christina Stecksén-Blicks Svante H. A. Twetman Sofia H. Tran?us 《PloS one》2015,10(2)
ObjectivesTo identify, appraise and summarize existing knowledge and knowledge gaps in practice-relevant questions in pediatric dentistry.MethodsA systematic mapping of systematic reviews was undertaken for domains considered important in daily clinical practice. The literature search covered questions in the following domains: behavior management problems/dental anxiety; caries risk assessment and caries detection including radiographic technologies; prevention and non-operative treatment of caries in primary and young permanent teeth; operative treatment of caries in primary and young permanent teeth; prevention and treatment of periodontal disease; management of tooth developmental and mineralization disturbances; prevention and treatment of oral conditions in children with chronic diseases/developmental disturbances/obesity; diagnosis, prevention and treatment of dental erosion and tooth wear; treatment of traumatic injuries in primary and young permanent teeth and cost-effectiveness of these interventions. Abstracts and full text reviews were assessed independently by two reviewers and any differences were solved by consensus. AMSTAR was used to assess the risk of bias of each included systematic review. Reviews judged as having a low or moderate risk of bias were used to formulate existing knowledge and knowledge gaps.ResultsOut of 81 systematic reviews meeting the inclusion criteria, 38 were judged to have a low or moderate risk of bias. Half of them concerned caries prevention. The quality of evidence was high for a caries-preventive effect of daily use of fluoride toothpaste and moderate for fissure sealing with resin-based materials. For the rest the quality of evidence for the effects of interventions was low or very low.ConclusionThere is an urgent need for primary clinical research of good quality in most clinically-relevant domains in pediatric dentistry. 相似文献
87.
Tomomi Ando Mina Nagumo Masayuki Ninomiya Kaori Tanaka Robert J. Linhardt Mamoru Koketsu 《Bioorganic & medicinal chemistry letters》2018,28(14):2422-2425
Coumarins are ubiquitous in higher plants and exhibit various biological actions. The aim of this study was to investigate the structure-activity relationships of coumarin derivatives on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in human hepatoma HepG2 cells. A series of coumarin derivatives were prepared and assessed for their cytoprotective effects. Among these, a caffeoyl acid-conjugated dihydropyranocoumarin derivative, caffeoyllomatin, efficiently protected against cell damage elicited by t-BHP. Our findings suggest that caffeoyllomatin appears to be a potent cytoprotective agent. 相似文献
88.
Intraclutch Hatch Synchronization in Pheasants and Mallard Ducks 总被引:1,自引:0,他引:1
Irene Persson Gunilla Andersson 《Ethology : formerly Zeitschrift fur Tierpsychologie》1999,105(12):1087-1096
Synchronization of hatching within clutches of precocial bird species can be achieved either by acceleration or retardation, i.e. by shortening or prolonging the incubation period. The ability of mallard ( Anas platyrhynchos ) and ring-necked pheasant ( Phasianus colchicus ) embryos to accelerate or retard hatching was tested by incubating separate clutches, of which three eggs had 2 d longer or shorter incubation time than the others, and observing their individual time of pipping (breaking of the shell). Mallard embryos were able to delay hatching by on average 0.6 d (43% of the eggs delayed at least 1 d), but were better at acceleration (on average 1.3 d; 91% of the eggs accelerated more than 1 d). Conversely, pheasant embryos were only able to accelerate by 0.4 d (50% accelerated more than 1 d), but were better at delaying the hatching (1.2 days; 77% delayed more than 1 d). This difference between the species may depend on different degrees of relatedness within clutches in pheasants and mallards. It may also be an effect of the more developed sensory and neuromuscular systems in galliforms; a reduction of the incubation period would mean that the development of, for example, locomotion would be insufficient at hatching. 相似文献
89.
A series of nucleotide-containing polyphenols has been synthesized by a simple, two-step enzymatic method. The binding properties of these synthetic polymers to complementary oligonucleotides have been evaluated using a commercially available oligo(dT)cellulose column. Complementary synthetic nucleosides were retained on this column to a greater extent than non-complementary synthetic nucleosides. These results suggest that the synthetic nucleosides prepared via this two-step enzymatic approach may have application as affinity matrices. 相似文献
90.
H G Garg P A Joseph B T Thompson C A Hales T Toida T Imanari I Capila R J Linhardt 《Archives of biochemistry and biophysics》1999,371(2):228-233
Fully sulfated heparin and other glycosaminoglycans, namely heparan, chondroitin, and dermatan sulfates, and hyaluronan have been prepared by using sulfur trioxide under mild chemical conditions. All these derivatives were assayed for antiproliferative activity on cultured bovine pulmonary artery smooth muscle cells (BPASMCs). No appreciable difference was found between heparin and fully sulfated heparin. Chondroitin and dermatan sulfates actually stimulated BPASMCs growth but full sulfonation made them strongly antiproliferative. Native hyaluronan was not antiproliferative but became strongly so after sulfonation. Neither acharan sulfate nor N-sulfoacharan sulfate had any antiproliferative activity. This suggests that O-sulfonation of the polysaccharide is critical for antiproliferative activity, whereas N-sulfonation of glucosamine residues is not. 相似文献