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Povzetek: Sexual size dimorphism theory predicts biased operational sex ratios (OSRs) and an uneven distribution of males among certain females. We studied this phenomenon through a field census of the giant wood spider Nephila pilipes (family Nephilidae) in Singapore, a species where females are, on average, 6.9 times larger than males. Specifically, we tested two hypotheses concerning male distribution, given their tendency to aggregate in certain female webs. The optimal female size hypothesis predicts that males would predominantly occupy webs of intermediate-sized females. The web clustering hypothesis posits that more males would be found in webs closer together compared to those farther apart. Our snapshot census revealed a female-biased OSR (females: males = 1.85) with an uneven distribution of males in female webs. Most males were found in webs of intermediate-sized females aligning with the optimal female size hypothesis. Proximity among female webs was indicative of male presence, lending support to the web clustering hypothesis. While our study's limited sample size warrants caution, we conclude that in N. pilipes, male occupation of female webs is facilitated by the clustering of webs, and males prefer to cohabit with optimally sized, receptive females.
Ključne besede: sexual size dimorphism, operational sex ratios (OSRs), male distribution, optimal female size hypothesis, web clustering hypothesis, female-biased OSR, intermediate-sized females, proximity of webs, male aggregation, arachnology, behavioral ecology, environmental zoology
Objavljeno v DiRROS: 03.09.2024; Ogledov: 72; Prenosov: 46
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Povzetek: Detection and identification of Chrysanthemum stem necrosis virus (CSNV).
Ključne besede: CSNV, diagnostics, method validation, EURL-Virology
Objavljeno v DiRROS: 02.09.2024; Ogledov: 121; Prenosov: 50
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Objavljeno v DiRROS: 27.08.2024; Ogledov: 144; Prenosov: 79
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Povzetek: Despite the key role of raptors (including birds of prey Falconiformes and owls Strigiformes) in ecosystems and their sensitivity to environmental change, a well coordinated, Europe-wide monitoring of raptors is lacking. EURAPMON, a Research Networking Programme of the European Science Foundation, was launched with the aim of establishing a sustainable Europewide network for monitoring of raptors. An overview of current monitoring schemes for raptor populations in 28 European countries, as reported by EURAPMON National Coordinators at the workshop in Murcia (Spain) in 2012, showed existing monitoring schemes to be limited to a restricted number of species (mostly diurnal and rare raptor species). The most widely monitored species are the Golden Eagle Aquila chrysaetos amongst diurnal raptors and the Eagle Owl Bubo bubo amongst owls. Broad coverage of a species range across Europe is reached only for restricted-range species. The key driver for monitoring, which is mostly coordinated by NGOs, is conservation, and the main end users are governmental institutions. International collaboration in the field of monitoring of raptors is mainly regional and not yet pan-European in scale. The involvement of volunteers in raptor monitoring was perceived as the main strength of many schemes, but insufficient manpower and a focus on rare species were recognised as the main weaknesses across Europe as a whole. Among priorities identified for the future development of monitoring schemes are: improvements to national coordination; support to increase the number of volunteers; and assurances of stable funding. Further analysis of EURAPMON questionnaires will identify knowledge gaps, which will steer good practice guidance on survey methodologies; the need for the latter was identified as the main benefit that National Coordinators expect to gain from international networking
Ključne besede: Europe, raptor monitoring scheme, birds of prey, owls, monitoring inventory
Objavljeno v DiRROS: 06.08.2024; Ogledov: 219; Prenosov: 138
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Povzetek: Introduction. CD133 is a marker for a population of glioblastoma (GBM) and normal neural stem cells (NNSC). We aimed to reveal whether the migratory potential and differentiation of these stem cells is associated with CD133 expression and with cathepsin proteases (Cats). Materials and methods. The invasiveness of normal NNSC, GBM/CD133+ cell lines and GBM spheroids was evaluated in 3D collagen, as well as of U87-MG and normal astrocytes (NHA) grown in monolayers in 2D Matrigel. Expression of Cats B, L and S was measured at mRNA and activity levels and their relation to invasiveness, to CD133 mRNA in 26 gliomas, and to the survival of these patients. Results. The average yield of CD133+ cells from GBM samples was 9.6%. Survival of patients with higher CD133 mRNA expression was significantly shorter (p< 0.005). Invasion, associated with proteolytic degradation of matrix, was higher in normal stem cells and GBM spheroids and cells than in isolated GBM CD133+ cells. In glioma samples, there was no correlation between CD133 mRNA expression and Cat mRNAs, but there was an inverse correlation with Cat activities. Conclusions. The study confirms CD133 as a prognostic marker for the survival of GBM patients. We demonstrated that NNSC have higher invasion potential and invade the collagen matrix in a mode different from that of GBM, initiating stem cell spheres. This result could have implications for the design of new therapeutics, including protease inhibitors that specifically target invasive tumour stem cells. Increased activity of cathepsins in CD133- cells suggests their role in the invasive behaviour of GBM.
Objavljeno v DiRROS: 05.08.2024; Ogledov: 185; Prenosov: 103
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