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Opis: Melipona scutellaris is a Brazilian stingless bee that is important for pollinating wild flora and agriculture crops. Fungicides have been widely used in agriculture, and floral residues can affect forager bees. The goal of our study was to evaluate the effects of sublethal concentrations of pyraclostrobin on the midgut ultrastructure of M. scutellaris forager workers. The bees were collected from three non-parental colonies and kept under laboratory conditions. The bees were orally exposed continuously for five days to pyraclostrobin in syrup at concentrations of 0.125 ng a.i./µL (FG1) and 0.005 ng a.i./µL (FG2). The control bees (CTL) were fed a no-fungicide sucrose solution, and the acetone solvent control bees (CAC) received a sucrose solution containing acetone. At the end of the exposure, the midguts were sampled, fixed in Karnovsky solution, and routinely processed for transmission electron microscopy. Ultrastructural analysis demonstrated that both the fungicide concentrations altered the midgut, such as cytoplasmic vacuolization (more intense in FG1), the presence of an atypical nuclear morphology, and slightly dilated mitochondrial cristae in the bees from the FG1 and FG2 groups (both more intense in FG1). Additionally, there was an alteration in the ultrastructure of the spherocrystals (FG1), which could be the result of cellular metabolism impairment and the excretion of toxic metabolites in the digestive cells as a response to fungicide exposure. The results indicate that ingested pyraclostrobin induced cytotoxic effects in the midgut of native stingless bees. These cellular ultrastructural responses of the midgut are a prelude to a reduced survival rate, as observed in previous studies.
Ključne besede: digestive tract, Meliponini, mitochondria, morphology, strobilurin, sublethal effects
Objavljeno v DKUM: 07.04.2025; Ogledov: 0; Prenosov: 2
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Opis: Helichrysum italicum (family Asteraceae), due to its various beneficial health effects, represents an important plant in the traditional medicine of Mediterranean countries. Currently, there is a renewed interest in this medicinal plant, especially in investigations involving the isolation and identification of its bioactive compounds from extracts and essential oils, as well as in experimental validation of their pharmacological activities. In this paper, we review the current knowledge on the beneficial health effects of Helichrysum italicum extracts, essential oils, and their major bioactive polyphenolic compounds, ranging from antioxidative, anti-inflammatory, and anticarcinogenic activities to their antiviral, antimicrobial, insecticidal, and antiparasitic effects. This review also provides an overview of the most promising extraction and distillation techniques for obtaining high-quality extracts and essential oils from Helichrysum italicum, as well as methods for determining their antioxidative, antimicrobial, anti-inflammatory, and anticarcinogenic activities. Finally, new ideas for in silico studies of molecular mechanisms of bioactive polyphenols from Helichrysum italicum, together with novel suggestions for their improved bioavailability through diverse encapsulation techniques, are introduced.
Ključne besede: Helichrysum italicum, polyphenolic compounds, biological effects, extraction methods, distillation methods, encapsulation methods
Objavljeno v DKUM: 15.03.2024; Ogledov: 327; Prenosov: 15
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Opis: The paper studies the effects of foreign (the US, the UK and the Chinese) and domestic economic policy uncertainty (EPU) shocks on unemployment in Germany, France, Italy and Spain. The analysis is run separately for the rates of adult and youth unemployment. Impulse responses derived from vector autoregressive models show that the magnitudes of the responses of the adult and youth segments of the labour market are quite different. Following an uncertainty shock, the youth unemployment rate increases significantly more than the adult unemployment rate. This is the case for France, Italy and Spain. The German labour market seems to be resistant to foreign (except Chinese) and domestic EPU shocks, while the remaining labour markets, foremost the Spanish and Italian ones, are susceptible to uncertainty shocks, especially to the US EPU shocks.
Ključne besede: economic policy uncertainty, youth unemployment, adult unemployment, spillover effects, impulse responses
Objavljeno v DKUM: 26.09.2023; Ogledov: 370; Prenosov: 34
Celotno besedilo (3,89 MB)
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Opis: Information on estimates of combining ability of the promising lines of breeding material is important for evolving higher yielding varieties of oilseed rape (Brassica napus L.). An experiment was conducted to quantitatively examine the genetic parameters of phenological traits, plant height, pods on main raceme, pods per plant and seed yield for eight oilseed rape genotypes using a half-diallel crosses. The result of the diallel analysis revealed significant mean squares of general and specific combining abilities (GCA and SCA) for all studied traits, indicating the importance of additive and non-additive genetic effects for these traits. On the other hand estimation of high narrow-sense heritability estimates for days to flowering, duration of flowering and pods on main raceme, indicated the prime importance of additive genetic effects for these traits. L420 and L401 with significant negative GCA effects for days to flowering and days to maturity were suitable for yielding early maturity combinations. L41, Zafar and L22 with significant positive GCA effects for seed yield were superior parents for increasing seed yield. The crosses with significant positive SCA effects for seed yield had at least one parent with significant positive GCA effects for this trait. The crosses including L41×L22, L41×LF2, Zafar×L22 and Zafar×L420 with seed yield of 3421.7, 3400, 3348.1 and 3311.3 kg ha-1 could be promising for determination of superior recombinants for high seed yield coupled with other growth characters in advanced generations of segregation.
Ključne besede: additive genetic effects, Brassica napus, degree of dominance, combining ability, heritability, oilseed rape, yield
Objavljeno v DKUM: 10.10.2018; Ogledov: 1341; Prenosov: 324
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Opis: The aims of this dissertation are to analyse the interdependence between C-B M&As and the quality of the institutional setting and observe the economic effects of that nexus at the macroeconomic level in 22 European transition countries between 2000-2014. Our underlying hypothesis is that the progress and durability of institutional reforms are factors that have a crucial influence on the economic performance of C-B M&As in transition countries. The dynamic relationship between the economic effects of C-B M&As and institutional quality is investigated by using the system Generalized Method of Moments estimator. Since the potential benefits of foreign direct investment are determined by the institutional setup, we used different governance indicators in our calculations, both individually and in terms of their interaction with C-B M&As. With the help of our empirical analysis, we established which aspects of institutional setting have contributed most to causing the economic effects of C-B M&As, using their interaction terms with this type of FDI, so we could focus most attention on these areas. Our results indicate that C-B M&As have a negative effect on GDP per capita in the initial period. This negative impact in the year of merger and acquisition could be explained by the rise in unemployment and the crowding-out of less efficient domestic companies which are not able to withstand the competitive pressure in the domestic market. The influence of one-year lagged C-B M&As is positive and significant, suggesting that this form of FDI might have a delayed effect. However, this type of FDI does not have a positive economic impact on host transition countries in the long-run because it might be motivated by rent-seeking interests. We show that the overall quality of the institutional setting (measured with the help of the EBRD indices of structural reforms and World Bank’s Governance Indicators) is important for GDP per capita in the short and long term. On the other hand, its interaction terms with C-B M&As are negative but not significant in current period. All governance dimensions stimulate GDP per capita of host transition countries. Our findings indicate that the higher level of C-B M&As with a negative impact offsets the positive effect of the control of corruption and the rule of law on economic growth both in short and long run. Voice and accountability were found to be important for explaining an FDI’s influence on GDP per capita. In terms of the influence on domestic investment, we have found that contemporaneous M&As have a crowding-out effect, while the influence of their lagged level has a crowding-in effect. Their long term impact is also negative and significant (when controlling for overall institutional quality index and separate governance indicators), suggesting that foreign investors reduce the competition on the domestic market over time. We show that foreign investors may be motivated by rent-seeking interests based on the fact that the interdependence of C-B M&As and the overall quality of the institutional setting had a negative effect on domestic investment. We have not found evidence to support our hypothesis that overall institutional reform (as well as the speed of implementation) and its interaction with C-B M&As encourages domestic investment in European transition countries. We have found that political stability has a positive effect on domestic investment and is the only significant variable of all the institutional factors. This means this governance indicator is a crucial determinant of domestic investment in transition countries. The only significant interaction terms with a negative effect on domestic investment, are between C-B M&As and the Rule of Law and overall institutional quality. Political Stability (positive coefficient) and the interaction terms between C-B M&As and Rule of Law and overall institutional quality (both negative coefficients) have a significant impact on domestic i
Ključne besede: the quality of the institutional setting, C-B M&As, transition countries, economic effects, governance
Objavljeno v DKUM: 28.06.2018; Ogledov: 1992; Prenosov: 142
Celotno besedilo (2,67 MB)