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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: Optimal planting speed of vacuum maize planters is usually suggested by planter’s manufacturers, while increased planting speed may influence plant spacing and finally yield. Our hypothesis was that by increasing planting speed over the suggested level plant spacing variability will also increase which will result in decrease of silage and grain yield and saving of seed and energy. The field trial consisted of three planting speeds of 7, 9 and 11 km/h in the form of random blocks. The following measurements were taken as follows: plant spacing, silage and grain yield, fuel and energy use at planting. Results in this study show that planting speed did not have significant influence on silage and grain yield of maize, while up to 10% less seed was needed per hectare and fuel and energy use was lower for 15%. By the increase of planting speed the distance between the plants in a row, and in most cases also the plant spacing variability increased. It was noticed that by increasing planting speed plant density decreased. This research established that at higher planting speeds significant increase of the silage yield per individual plant and of the grain yield per individual plant was achieved. The ear parameters also show that the kernel mass per individual ear, the ear mass, and the cob mass, as well as the individual kernel mass, are larger at the planting speed of 11 km/h than at the planting speed of 7 km/h. At the latter planting speed, significantly higher fuel consumption per hectare and higher energy use was achieved than at the other two planting speeds. Overall the main benefits of planting speed of 11 km/h is saving seed and energy at planting while maintaning the same level of silage and grain yield compared to lower planting speeds used in the trial.
Ključne besede: energy use, grain yield, maize, planting speed, plant spacing, seed savings, silage yield, vacuum planter
Objavljeno v DKUM: 11.03.2025; Ogledov: 0; Prenosov: 4
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Opis: Zbornik vključuje povzetke prispevkov, ki so bili predstavljeni na 8. Posvetu o ohranjanju in trajnostni rabi rastlinskih genskih virov (RGV), organiziranem s strani Univerze v Mariboru, Fakultete za kmetijstvo in biosistemske vede, v sodelovanju z Ministrstvom za kmetijstvo, gozdarstvo in prehrano. Namen vsakoletnega posveta je ozaveščanje javnosti o pomembnosti ohranjanja RGV v Sloveniji, predstavitev novosti na tem področju, pregled dosežkov ter izmenjava izkušenj med sodelujočimi. Zaradi omejenega obsega razpoložljivih finančnih sredstev so trenutne dejavnosti JSRGB usmerjene predvsem v ohranitev obstoječih zbirk lokalnih genskih virov kmetijskih rastlin, manj pa je aktivnosti na področju sistematičnega ocenjevanja RGV glede uporabne vrednosti, tako v genskih bankah ex situ kot na njihovem naravnem rastišču in situ. Osrednja tema letošnjega posveta so bili trajni nasadi in sicer so bili v prvem sklopu predstavljeni prispevki, ki so obravnavali sadne rastline, v drugem sklopu pa so sledila predavanja na temo trajnih nasadov vinske trte. Ob zaključku so bile podane možnosti vzpostavitve ohranjanja RGV na kmetijah. Poudarjen je bil tudi pomen sistema kakovosti pri vodenju genskih bank.
Ključne besede: vodenje kakovosti, genska banka, trajni nasadi, tradicionalni genotipi sliv, genska banka vinske trte
Objavljeno v DKUM: 20.02.2025; Ogledov: 0; Prenosov: 6
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Opis: Modern pig breeds, which have been genetically improved to achieve fast growth and a lean meat deposition, differ from local pig breeds with respect to fat deposition, fat specific metabolic characteristics and various other properties. The present review aimed to elucidate the mechanisms underlying the differences between fatty local and modern lean pig breeds in adipose tissue deposition and lipid metabolism, taking into consideration morphological, cellular, biochemical, transcriptomic and proteomic perspectives. Compared to modern breeds, local pig breeds accumulate larger amounts of fat, which generally contains more monounsaturated and saturated fatty acids; they exhibit a higher adipocyte size and higher activity of lipogenic enzymes. Studies using transcriptomic and proteomic approaches highlighted several processes like immune response, fatty-acid turn-over, oxidoreductase activity, mitochondrial function, etc. which differ between local and modern pig breeds.
Ključne besede: pig, adipose tissue, local breeds, modern breeds, cellularity, transcriptome, proteom, adaptation
Objavljeno v DKUM: 06.02.2025; Ogledov: 0; Prenosov: 3
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Opis: In this paper, the quality of the municipal waste sorting process in seven waste management centers in Slovenia was assessed using the qualitative multicriteria analysis (MCA) method DEX (Decision EXpert) implemented in DEXi software, which is based on multicriteria decomposition of the problem and utility functions in the form of ʺif-thenʺ decision rules. The study was based on eight types of secondary raw materials. The quality of the secondary raw materials, the regularity of the delivery of secondary raw materials to recycling units based on the sorting efficiency, and the loading weight of the individual baled fractions in the transport of secondary raw materials for recycling were the main parameters used in the model. The final assessment shows good waste management service in centers A and D. Centers B, C, and F were rated ʺaverageʺ. The ʺbadʺ rating was assigned to centers E and G.
Ključne besede: waste sorting, quality management, multicriteria decision analysis, expert system DEXi
Objavljeno v DKUM: 03.02.2025; Ogledov: 0; Prenosov: 4
Celotno besedilo (2,88 MB)
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