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71.
Per Mrin Roland Rosmond Bengt-ke Bengtsson Carola Gustafsson Gran Holm Per Bjmtorp 《Obesity (Silver Spring, Md.)》1994,2(3):263-270
Visceral obese men were characterized by a decreased total GH secretion and diminished peak amplitude, size, and number. T-substitution was followed by elevation of IGF-I levels. The IGF-I increase correlated with the elevation of T-concentration, and was most pronounced in men with the lowest concentrations of free T from the outset. There were no detectable changes in total quantity, amplitude, size or number of peaks of GH secretion. Glucose, cholesterol and triglycerides as well as diastolic blood pressure decreased. There were no changes in thyroid or hematology variables. Visceral obesity in men has been reported to be characterized by low testosterone (T) and insulin-like growth factor I (IGF-I) concentrations, the latter suggesting a relative growth hormone (GH) deficiency. Since T and GH-secretions are interrelated, men with visceral obesity were substituted with T for 14 days, and diurnal secretion pattern of GH as well as IGF-I concentrations, and metabolic variables were followed. T-substitution of visceral obese men is followed by an elevation of IGF-I concentrations. It is suggested that this might be due either to minor, non-detectable increases in GH secretion, or to direct effects of T on IGF-I concentrations. The regulatory mechanisms by which T-administration are leading to metabolic and anthropometric improvements, might be direct effects of T, with or without mediation via GH secretion. 相似文献
72.
Cell-free supernatant of pelleted zoospores was found to be more suitable for maintaining viable zoospores and developed cysts
than the supernatant of mature cysts. Conductivity and pH measurements indicated quantitative changes in the ionic composition
of a suspension ofP. infestans zoospores during their conversion into cysts. An increase in conductivity in the incipient cyst suspension was followed by
a decrease of conductivity in the maturing cyst suspension. The conductivity changes correlated closely with K+ fluxes which, in turn, coincided with the reverse, but stoichiometrically smaller, H+ fluxes. Zoospores treated with 1.5 μmol/L DCCD (an inhibitor of plasma membrane H+-ATPase) or 100 mmol/L Li+ (an inhibitor of cell motility) released predominantly K+ and other cations and their O2 consumption decreased. The H+/K+ exchange is therefore very probably associated with an operation of the plasma membrane H+-ATPase. The differential decrease in respiration caused by DCCD and Li+ was used to estimate the energy demand for cell motility and spore development. 相似文献
73.
Eszter Szász Fanni Sarkadi Eszter Szöllősi Renáta Kopena János Török Balázs Rosivall 《Journal of evolutionary biology》2023,36(1):156-168
Brood sex ratios (BSRs) have often been found to be nonrandom in respect of parental and environmental quality, and many hypotheses suggest that nonrandom sex ratios can be adaptive. To specifically test the adaptive value of biased BSRs, it is crucial to disentangle the consequences of BSR and maternal effects. In multiparous species, this requires cross-fostering experiments where foster parents rear offspring originating from multiple broods, and where the interactive effect of original and manipulated BSR on fitness components is tested. To our knowledge, our study on collared flycatchers (Ficedula albicollis) is the first that meets these requirements. In this species, where BSRs had previously been shown to be related to parental characteristics, we altered the original BSR of the parents shortly after hatching by cross-fostering nestlings among trios of broods and examined the effects on growth, mortality and recruitment of the nestlings. We found that original and experimental BSR, as well as the interaction of the two, were unrelated to the fitness components considered. Nestling growth was related only to background variables, namely brood size and hatching rank. Nestling mortality was related only to hatching asynchrony. Our results therefore do not support that the observed BSRs are adaptive in our study population. However, we cannot exclude the possibility of direct effects of experimentally altered BSRs on parental fitness, which should be evaluated in the future. In addition, studies similar to ours are required on various species to get a clearer picture of the adaptive value of nonrandom BSRs. 相似文献
74.
Darja Lavogina Naila Nasirova Tanel Sõrmus Taavo Tähtjärv Erki Enkvist Kaido Viht Tõiv Haljasorg Koit Herodes Jana Jaal Asko Uri 《Journal of peptide science》2023,29(3):e3456
The conjugates of an adenosine mimetic and oligo-l -arginine or oligo-d -arginine (ARCs) were initially designed in our research group as inhibitors and photoluminescent probes targeting basophilic protein kinases. Here, we explored a panel of ARCs and their fluorescent derivatives in biochemical assays with members of the protein arginine methyltransferase (PRMT) family, focusing specifically on PRMT1. In the binding/displacement assay with detection of fluorescence anisotropy, we found that ARCs and arginine-rich peptides could serve as high-affinity ligands for PRMT1, whereas the equilibrium dissociation constant values depended dramatically on the number of arginine residues within the compounds. The fluorescently labeled probe ARC-1081 was displaced from its complex with PRMT1 by both S-adenosyl-l -methionine (SAM) and S-adenosyl-l -homocysteine (SAH), indicating binding of the adenosine mimetic of ARCs to the SAM/SAH-binding site within PRMT1. The ARCs that had previously shown microsecond-lifetime photoluminescence in complex with protein kinases did not feature such property in complex with PRMT1, demonstrating the selectivity of the time-resolved readout format. When tested against a panel of PRMT family members in single-dose inhibition experiments, a micromolar concentration of ARC-902 was required for the inhibition of PRMT1 and PRMT7. Overall, our results suggest that the compounds containing multiple arginine residues (including the well-known cell-penetrating peptides) are likely to inhibit PRMT and thus interfere with the epigenetic modification status in complex biological systems, which should be taken into consideration during interpretation of the experimental data. 相似文献
75.
76.
Neuza Domingues André R. A. Marques Rita Diogo Almeida Calado Inês S. Ferreira Cristiano Ramos José Ramalho Maria I. L. Soares Telmo Pereira Luís Oliveira José R. Vicente Louise H. Wong Inês C. M. Simões Teresa M. V. D. Pinho e Melo Andrew Peden Cláudia Guimas Almeida Clare E. Futter Rosa Puertollano Winchil L. C. Vaz Otília V. Vieira 《Traffic (Copenhagen, Denmark)》2023,24(7):284-307
77.
Martina Ferraguti Sergio Magallanes Jéssica Jiménez-Peñuela Josué Martínez-de la Puente Luz Garcia-Longoria Jordi Figuerola Jaime Muriel Tamer Albayrak Staffan Bensch Camille Bonneaud Rohan H. Clarke Gábor Á. Czirják Dimitar Dimitrov Kathya Espinoza John G. Ewen Farah Ishtiaq Wendy Flores-Saavedra László Zsolt Garamszegi Olof Hellgren Dita Horakova Kathryn P. Huyvaert Henrik Jensen Asta Križanauskienė Marcos R. Lima Charlene Lujan-Vega Eyðfinn Magnussen Lynn B. Martin Kevin D. Matson Anders Pape Møller Pavel Munclinger Vaidas Palinauskas Péter L. Pap Javier Pérez-Tris Swen C. Renner Robert Ricklefs Sergio Scebba Ravinder N. M. Sehgal Manuel Soler Eszter Szöllősi Gediminas Valkiūnas Helena Westerdahl Pavel Zehtindjiev Alfonso Marzal 《Global Ecology and Biogeography》2023,32(5):809-823
Aim
The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations.Location
Global.Time period
2002–2019.Major taxa studied
Avian Plasmodium parasites in house sparrows.Methods
We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests.Results
Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected.Main conclusions
Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows. 相似文献78.
Low-sulphated oligosaccharides derived from heparan sulphate inhibit normal angiogenesis 总被引:1,自引:0,他引:1
Hahnenberger Rudolph; Jakobson ke M.; Ansari Akbar; Wehler Thomas; Svahn Carl Magnus; Lindahl Ulf 《Glycobiology》1993,3(6):567-573
Heparin, with or without the addition of an adrenocorticosteroid,can inhibit normal angiogenesis in the chick embryo chorioallantoicmembrane. Low- or non-sulphated heparin fragments also haveanti-angiogenic effect. Attempts to define a saccharide structureresponsible for the anti-angiogenic effect implicated a -[GlcAß1,4-GlcNAc 相似文献
79.
Anuran males emit advertisement calls for the purpose of attracting females and repelling conspecific males. Call transmission is influenced by the acoustics of the propagation environment, including vegetation. Thus, forestry monocultures of non-native trees represent artificial environments that could modify call transmission. These monocultures have substituted large areas of Atlantic Forest in southern Brazil, representing a conservation challenge. Considering this context, we hypothesized that anurans have calls that are less attenuated in their native environment than in forest plantations. To test it, we performed sound transmission experiments using calls of three anuran species native to southern Brazil: Boana bischoffi, B. leptolineata, and Hylodes meridionalis. We compared sound attenuation between the native forest and forestry monocultures (Eucalyptus sp. and Pinus sp. forests), and included distance from the sound source, air temperature, humidity, and vegetation density as cofactors in linear mixed models. Our results show that the advertisement calls of the two tree frogs (Boana) attenuate less in tree plantations than in native forests, while the third species shows either no differences or less attenuation in native forests. Our results can be understood according to differences in natural history and microhabitat use among the studied species. The two tree frog species vocalize perched from vegetation so their calls become better transmitted in forestry monocultures, which have fewer trees than the native forest. On the other hand, H. meridionalis calls from rocks on streams and the propagation is finely tuned to this peculiar microhabitat. We discuss the conservation implications of our findings for anurans and for the Atlantic Forest. Abstract in Portuguese and Spanish are available with online material. 相似文献
80.
Thomas Ljung Bjrn Andersson Bengt-ke Bengtsson Per Bjrntorp Per Mrin 《Obesity (Silver Spring, Md.)》1996,4(3):277-282
In this study, dexamethasone (dex) was administered in random order in doses of 0.05, 0.125, 0.25 and 0.5 mg at 10 p.m. with measurements of serum Cortisol in the morning (8 a.m.) of this and the following day. The test was performed on 22 apparently healthy men, 40 to 60 years of age, recruited from laboratory personnel, outpatient clinics or advertisements in a newspaper. Eight had a body mass index (BMI) (kg/m2) of <25 and 14 of >25. Twelve men had a waist hip ratio (WHR) of <1.0 and 10 men had a WHR of<1.0. Cortisol values at baseline were correlated inversely with WHR and were usually lower in men with a high (>1.0) rather than a low than low (<1.0) WHR after dex inhibition. There was apparently no inhibition by dex at 0.05 and 0.125 mg on average in men with a WHR of >1.0. In addition, the inhibition at 0.5 mg dex correlated negatively with the WHR and was significantly lower (p<0.05) in men with a WHR of >1.0 than in men with a WHR of <1.0. None of these differences or relationships was found to be dependent on BMI. It is concluded that men with an elevated WHR experience a decrease in the inhibition of Cortisol secretion by dex. It is suggested that this could explain or contribute to the elevated sensitivity of their HPA axis. Furthermore, lower morning Cortisol concentrations suggest a change in diurnal secretion patterns. 相似文献