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2. Okadaic acid as a major problem for the seafood safety (Mytilus galloprovincialis) and the dynamics of toxic phytoplankton in the Slovenian coastal sea (Gulf of Trieste, Adriatic Sea)Urška Henigman, Patricija Mozetič, Janja Francé, Tanja Knific, Stanka Grebenc, Jožica Dolenc, Andrej Kirbiš, Majda Biasizzo, 2024, original scientific article Abstract: This article presents the first results on shellfish toxicity in the Slovenian sea (Gulf of Trieste, Adriatic Sea) since the analytical methods for the detection of biotoxins (PSP, ASP, DSP and other lipophilic toxins) in bivalve molluscs were included in the national monitoring program in 2013. In addition to toxins, the composition and abundance of toxic phytoplankton and general environmental characteristics of the seawater (surface temperature and salinity) were also monitored. During the 2014–2019 study period, only lipophilic toxins were detected (78 positive tests out of 446 runs), of which okadaic acid (OA) predominated in 97% of cases, while dinophysistoxin-2 and yessotoxins only gave a positive result in one sampling event each. The number of samples that did not comply with the EC Regulation for the OA group was 17 or 3.8% of all tests performed, all of which took place from September to November, while a few positive OA tests were also recorded in December, April, and May. This toxicity pattern was consistent with the occurrence pattern of the five most common DSP-producing dinoflagellates, which was supported by the development of warm and thermohaline stratified waters: Dinophysis caudata, D. fortii, D. sacculus, D. tripos and Phalacroma rotundatum. The strong correlation (r = 0.611, p<0.001) between D. fortii, reaching abundances of up to 950 cells L−1, and OA suggests that D. fortii is the main cause of OA production in Slovenian waters. Strong interannual variations in OA and phytoplankton dynamics, exacerbated by the effects of anthropogenic impacts in this coastal ecosystem, reduce the predictability of toxicity events and require continuous and efficient monitoring. Our results also show that the introduction of the LC-MS/MS method for lipophilic toxins has improved the management of aquaculture activities, which was not as accurate based on mouse bioassays.
Keywords: biotoxins, okadaic acid, toxic phytoplankton, LC-MS/MS, toxicity, Adriatic Sea, hydrobiology, marine biology
Published in DiRROS: 19.06.2024; Views: 36; Downloads: 16
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3. Wing buzzing as a mechanism for generating vibrational signals in psyllids (Hemiptera: Psylloidea)Jernej Polajnar, Elizaveta Kvinikadze, Adam W. Harley, Igor Malenovský, 2024, original scientific article Abstract: Psyllids, or jumping plant lice (Hemiptera: Sternorrhyncha: Psylloidea), are a group of small phytophagous insects that include some important pests of crops worldwide. Sexual communication of psyllids occurs via vibrations transmitted through host plants, which play an important role in mate recognition and localization. The signals are species-specific and can be used to aid in psyllid taxonomy and pest control. Several hypotheses have been proposed for the mechanism that generates these vibrations, of which stridulation, that is, friction between parts of the forewing and thorax, has received the most attention. We have investigated vibrational communication in the European pear psyllid species Cacopsylla pyrisuga (Foerster, 1848) using laser vibrometry and high-speed video recording, to directly observe the movements associated with signal production. We describe for the first time the basic characteristics of the signals and signal emission of this species. Based on observations and analysis of the video recordings using a point-tracking algorithm, and their comparison with laser vibrometer recordings, we argue that males of C. pyrisuga produce the vibrations primarily by wing buzzing, that is, tremulation that does not involve friction between the wings and thorax. Comparing observed signal properties with previously published data, we predict that wing buzzing is the main mechanism of signal production in all vibrating psyllids.
Keywords: biotremology, substrate-borne vibrational signals, vibrational signals, jumping plant lice, tremulation
Published in DiRROS: 19.06.2024; Views: 31; Downloads: 25
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4. DNA barcoding insufficiently identifies European wild bees (Hymenoptera, Anthophila) due to undefined species diversity, genus-specific barcoding gaps and database errorsJanko Šet, Rok Šturm, Blaž Koderman, Danilo Bevk, Andrej Gogala, Denis Kutnjak, Klemen Čandek, Matjaž Gregorič, 2024, original scientific article Keywords: insect pollinators, wild bees, DNA, biodiversity, databases
Published in DiRROS: 19.06.2024; Views: 33; Downloads: 23
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5. The activation of iron deficiency responses of grapevine rootstocks is dependent to the availability of the nitrogen formsSarhan Khalil, Rebeka Strah, Arianna Lodovici, Petr Vojta, Federica De Berardinis, Jörg Ziegler, Maruša Pompe Novak, Laura Zanin, Nicola Tomasi, Astrid Forneck, Michaela Griesser, 2024, original scientific article Abstract: Background In viticulture, iron (Fe) chlorosis is a common abiotic stress that impairs plant development and leads to yield and quality losses. Under low availability of the metal, the applied N form (nitrate and ammonium) can play a role in promoting or mitigating Fe deficiency stresses. However, the processes involved are not clear in grapevine. Therefore, the aim of this study was to investigate the response of two grapevine rootstocks to the interaction between N forms and Fe uptake. This process was evaluated in a hydroponic experiment using two ungrafted grapevine rootstocks Fercal (Vitis berlandieri x V. vinifera) tolerant to deficiency induced Fe chlorosis and Couderc 3309 (V. riparia x V. rupestris) susceptible to deficiency induced Fe chlorosis. Results The results could differentiate Fe deficiency effects, N-forms effects, and rootstock effects. Interveinal chlorosis of young leaves appeared earlier on 3309 C from the second week of treatment with NO3 −/NH4 + (1:0)/- Fe, while Fercal leaves showed less severe symptoms after four weeks of treatment, corresponding to decreased chlorophyll concentrations lowered by 75% in 3309 C and 57% in Fercal. Ferric chelate reductase (FCR) activity was by trend enhanced under Fe deficiency in Fercal with both N combinations, whereas 3309 C showed an increase in FCR activity under Fe deficiency only with NO3 −/NH4 + (1:1) treatment. With the transcriptome analysis, Gene Ontology (GO) revealed multiple biological processes and molecular functions that were significantly regulated in grapevine rootstocks under Fe-deficient conditions, with more genes regulated in Fercal responses, especially when both forms of N were supplied. Furthermore, the expression of genes involved in the auxin and abscisic acid metabolic pathways was markedly increased by the equal supply of both forms of N under Fe deficiency conditions. In addition, changes in the expression of genes related to Fe uptake, regulation, and transport reflected the different responses of the two grapevine rootstocks to different N forms. Conclusions Results show a clear contribution of N forms to the response of the two grapevine rootstocks under Fe deficiency, highlighting the importance of providing both N forms (nitrate and ammonium) in an appropriate ratio in order to ease the rootstock responses to Fe deficiency.
Keywords: vitis, iron uptake, chlorosis, nitrate, ammonium, RNA-Seq
Published in DiRROS: 19.06.2024; Views: 30; Downloads: 14
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6. A spider mating plug functions to protect spermHe Jiang, Yongjia Zhan, Qingqing Wu, Huitao Zhang, Matjaž Kuntner, Lihong Tu, 2024, original scientific article Abstract: Mating plugs in animals are ubiquitous and are commonly interpreted to be products of mating strategies. In spiders, however, mating plugs may also take on functions beyond female remating prevention. Due to the vagaries of female genital (spermathecal) anatomy, most spiders face the problem of having to secure additional, non-anatomical, protection for transferred sperm. Here, we test the hypothesis that mating plugs, rather than (or in addition to) being adaptations for mating strategies, may serve as sperm protection mechanism. Based on a comparative study on 411 epigyna sampled from 36 families, 187 genera, 330 species of entelegyne spiders, our results confirm the necessity of a sperm protection mechanism. We divided the entelegyne spermathecae into four types: SEG, SED, SCG and SCD. We also studied detailed morphology of epigynal tracts in the spider Diphya wulingensis having the SEG type spermathecae, using 3D-reconstruction based on semi thin histological series section. In this species, we hypothesize that two distinct types of mating plug, the sperm plug and the secretion plug, serve different functions. Morphological details support this: sperm plugs are formed on a modified spermathecal wall by the spilled sperm, and function as a temporary protection mechanism to prevent sperm from leaking and desiccating, while secretion plugs function in postcopulation both as a permanent protection mechanism, and to prevent additional mating. Furthermore, with the modified spermathecal wall of S2 stalk, the problem of shunt of sperm input and output, and the possibility of female multiple mating have been resolved. Variation in spermathecal morphology also suggests that the problem of sperm protection might be resolved in different ways in spiders. Considering mating plugs of varying shapes and origins in the vast morphospace of spiders, we conclude that mating plugs might serve different purposes that relate both to mating strategies, as well as to sperm protection.
Keywords: spiders, mating strategies, mating plugs, sperm protection mechanism
Published in DiRROS: 19.06.2024; Views: 32; Downloads: 14
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8. Poročilo o preskusu št.: LVG 2024-053 : vzorec št. 2024/00116Tine Hauptman, Zina Devetak, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Geosmithia morbida, bolezen tisočerih rakov, vektorji, rtPCR
Published in DiRROS: 19.06.2024; Views: 44; Downloads: 0
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10. Poročilo o preskusu št.: LVG 2024-051 : vzorec št. 2024/00087Tine Hauptman, Špela Hočevar, Barbara Piškur, 2024, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Euwallacea fornicatus, Neocosmospora euwallaceae, strokovne naloge IVHVVR, molekularne analize
Published in DiRROS: 19.06.2024; Views: 39; Downloads: 2
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