SAB

Phenolic compounds in wetland macrophytes

Phenolics are the most widely distributed class of plant secondary metabolites and higher plants are able to produce several thousand different phenolic compounds. It has been reported that phenolics are more resistant to decomposition due to the negative impact on the microorganisms involved. Therefore, it may be hypothesized that the higher content of phenolics in plant tissue may cause slower decomposition rates and potentially higher carbon sequestration in the soil. The primary goal of this study was to evaluate and compare the content of phenolics in seven common macrophytes in the Czech Republic. Aboveground biomass was sampled in June 2016 at seven different localities and phenolics concentrations determined by spectrophotometric methods according to the Folin-Cioacalteau method ranged from 9.02 to 28.39 g kg–1 dry biomass weight (DW). Several plants were also harvested in August, October and December in order to follow a seasonal pattern. According to the results it seems that surveyed macrophytes vary widely in phenolics concentrations in relation to sampled site, harvesting time, plant species, and plant parts as well.

phenolic compounds, wetland plant species, decomposition, carbon

Dvořáková Březinová, T., Vymazal, J. (2018): Phenolic compounds in wetland macrophytes. Scientia Agriculturae Bohemica, 49, 1-8. DOI: 10.2478/sab-2018-01

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Organo-sulphur garlic compounds influence viability of mammalian cells: A Review

Garlic is still in the centre of interest for its therapeutic effects. Currently, attention is focused on physiological effects of organo-sulphur garlic compounds, as alliin, allicin, diallyl sulfide (DAS), diallyl disulfide (DADS), diallyl trisulfide (DATS), and S-allyl cysteine (SAC), particularly on their antioxidant and anticancerogenic effects. SAC has been studied for its ability to decrease the production of reactive oxygen species by modulation of the cell glutathione level together with antioxidative enzyme activity, and by improvement of mitochondrial functions. The main mechanism of DAS, DADS, and DATS is the induction of the internal apoptotic pathway. Garlic compounds have the ability to interfere with the signalling pathways of small gaseous signalling molecules known as gasotransmitters – nitric oxide, hydrogen sulfide, and carbon monoxide. The review presents the effect of garlic compounds on cellular oxidative stress, intrinsic apoptotic and gasotransmitter pathways and compares their effects on tumour and normal mammalian cells.

garlic products, oxidative stress, ROS, H2S, NO, CO

Chmelíková, E., Němeček, D., Dvořáková, M., Heroutová, I., Sedmíková, M. (2018): Organo-sulphur garlic compounds influence viability of mammalian cells: A review. Scientia Agriculturae Bohemica, 49, 9-16. DOI: 10.2478/sab-2018-02

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Screening of model animals for experimental infection with equine cyathostomes

Various laboratory animals – mice (Mus musculus) of six strains, rabbits (Oryctolagus cuniculus), guinea pigs (Cavia porcellus), rats (Rattus norvegicus), and Mongolian gerbils (Meriones unguiculatus) were experimentally infected with larvae of small strongyles (Cyathostominae), obtained from horse faeces and cultured to the infective larval stage L3. The attempt to transfer cyathostome larvae was aimed at developing a model for the investigation of different aspects of the life cycle and biology of these nematodes in the laboratory. Some animals were immunized (hydrocortisone) for the duration of the study. The laboratory animals were orally infected with 2–10 thousand sheathed or ex-sheathed L3 larvae of mixed cyathostome species. All attempts to inoculate any animal failed? there was no larval development in the experimental rodents and it can be stated that none of the investigated animals may serve as a suitable model host for horse nematodes of the subfamily Cyathostominae.

small strongyles, cyathostomiasis, experimental models, rabbits, guinea pigs, Mongolian gerbils

Scháňková, Š., Langrová, I,. Jankovská, I., Vadlejch, J., Čadková, Z., Křivská, D. (2018): Screening of model animals for experimental infection with equine cyathostomes. Scientia Agriculturae Bohemica, 49, 17-20. DOI: 10.2478/sab-2018-03

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Parasites of Myocastor coypus – a comparison in farm animals and their feral counterparts

The parasitic status in the coypus (nutrias) Myocastor coypus, both farm-bred or free-living on river banks in the Czech Republic, was determined. Faecal samples were collected from 200 coypus originating from 11 farms (farm-bred animals) and from 20 individuals living at 14 natural localities (feral animals). Faeces were examined for nematode eggs and coccidian oocysts using the McMaster method. The evaluation of faeces from farm-bred coypus indicated infection with the following parasites: Trichuris sp., Strongyloides sp., Trichostrongylus sp., Eimeria seidelli, Eimeria nutriae, Eimeria coypi, and Eimeria myopotami. Free-living feral rodents harboured Eimeria nutriae, E. coypi, Strongyloides sp. and in one case also Trichuris sp. An additional visceral examination of 20 coypus originating from five farms revealed two nematode species in the gastrointestinal tracts, namely Trichuris myocastoris and Strongyloides myopotami. The study indicated that feral coypus are far less parasitized than their captive counterparts.

coypu, nutria, nematodes, Trichuris myocastoris, Strongyloides myopotami, cocccidia, Eimeria

Nechybová, S., Langrová., Tůmová, E. (2018): Parasites of Myocastor coypus – a comparison in farm animals and their feral counterparts. Scientia Agriculturae Bohemica, 49, 21-25. DOI: 10.2478/sab-2018-04

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Ecotoxicity of wastewater from medical facilities: A Review

Wastewater from medical facilities contains a wide range of chemicals (in particular pharmaceuticals, disinfectants, heavy metals, contrast media, and radionuclides) and pathogens, therefore it constitutes a risk to the environment and human health. Many micropollutants are not efficiently eliminated during wastewater treatment and contaminate both surface water and groundwater. As we lack information about the long-term effects of low concentrations of micropollutants in the aquatic environment, it is not possible to rule out their adverse effects on aquatic organisms and human health. It is, therefore, necessary to focus on the evaluation of chronic toxicity in particular when assessing the environmental and health risks and to develop standards for the regulation of hazardous substances in wastewater from medical facilities on the basis of collected data. Wastewater from medical facilities is a complex mixture of many compounds that may have synergetic, antagonistic or additive effects on organisms. To evaluate the influence of a wide range of pollutants contained in the effluents from medical facilities on aquatic ecosystems, it is necessary to determine their ecotoxicity.

hospital wastewater, health and environmental risks, pharmaceuticals

Cidlinová, A., Wittlingerová, Z., Zimová, M., Chrobáková, T., Petruželková, A. (2018): Ecotoxicity of wastewater from medical facilities: A Review Scientia Agriculturae Bohemica, 49, 26-31 DOI: 10.2478/sab-2018-05

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Stream level stabilization by algae of the genus Cladophora

Investigations in the Pryský brook experimental catchment revealed that the vegetation of the stream channel stabilizes water level depth in the measured profile. The explored brook has been heavily overgrown by algae of the genus Cladophora due to a strong pollution by nitrates. It seems that if the algae average length exceeds the midsize of the stones paving the bed (ca. 30 ± 7 cm in diameter, escribed circle to pentagon or heptagon), the water level stagnates in the flowrate range of 60–180 l s–1. This totally blocks the streamflow daily oscillation (in summer months in a purely stone bed reaching up to 15%, along with tidal phenomena). The article analyzes one of possible explanations of this effect due to the dependence of the algae thickness layer modifying the channel bed cross-section on the speed of flowing water.

catchment parameters, water level, algae of the genus Cladophora, daily fluctuation of discharge

Zeman, J., Dvořáková, Š. (2018): Stream level stabilization by algae of the genus Cladophora. Scientia Agriculturae Bohemica, 49, 32-37. DOI: 10.2478/sab-2018-06

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Production and commercialization of timber in Angola after the declaration of independence

The policy of production and commercialization of timber before and after the independence of Angola was assessed. Historical production of timber under control of Portuguese settlers before 1975 in comparison to the production of timber after this period was reviewed. We used a combination of published scientific studies and government reports to support the background of the paper and a structured questionnaire survey from which analyses were drawn using a logistic regression model. It was found out that timber production declined dramatically after Angola gained independence; the production of logs dropped from 555 000 m3 in 1973 to less than 115 400 m3. Out of the 100 mills that had existed in Angola before 1975 only twenty have been in operation today with annual wood production of less than 20% of extraction capacity. The knowledge concerning the historical production of timber before and after 1975 is not sufficient to provide suggestions for a management plan on what trees, where, and when are to be cut.

Angolan forest, forest management, forest ownerships, sawmill, wood industry

Chiteculo, V., Hájek, M., Kubová, P. (2018): Production and commercialization of timber in Angola after the declaration of independence. Scientia Agriculturae Bohemica, 49, 38-45. DOI: 10.2478/sab-2018-07

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Antibacterial effect of carvacrol and coconut oil on selected pathogenic bacteria

Essential oils play a prominent role as flavouring agents and fragrances in the food and perfume industries. Carvacrol is a major component of various essential oils, such as oregano and thyme oils, and is responsible for their antimicrobial activity. Lauric acid is a medium-chain fatty acid (MCFA) with a high antibacterial potential. Both carvacrol and MCFAs have been used empirically as antimicrobial agents. Here, we tested the inhibitory properties of carvacrol and coconut (Cocos nucifera L.) oil containing a high percentage of MCFAs against 5 harmful bacterial pathogens: Escherichia coli, Salmonella Enteritidis, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus cecorum. Gas chromatography (GC-FID) analysis of coconut oil showed a high concentration of lauric acid (41%). Microdilution antimicrobial assays showed that the combination of carvacrol and coconut oil had a stronger antibacterial effect against all tested bacteria than both agents separately. We conclude that carvacrol could significantly improve the antibacterial effect of coconut oil.

terpene, coconut, foodborne pathogens

Božik, M., Hovorková, P., Klouček, P. (2018): Antibacterial effect of carvacrol and coconut oil on selected pathogenic bacteria. Scientia Agriculturae Bohemica, 49, 46-52. DOI: 10.2478/sab-2018-08

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Exploitation of hazelnut (Corylus avellana) shell waste in the form of polymer–particle biocomposite

Mechanically ground hazelnut (Corylus avellana) shells, a food industry by-product of hazelnuts processing, were tested for use as a composite material filler. Mechanical properties and fracture surface of the composite were evaluated using scanning electron microscopy. Polymer composites, i.e. resins filled with microparticles of hazelnut shells, were tested at various concentrations of the filler (5, 10, 20, 30, and 40 wt%). Hazelnut shell microparticles used at low concentration (5 wt%) increased tensile strength. The filler did not considerably influence hardness of the composite. Adhesive bond strength did not significantly change up to 20 wt%. The hazelnut shell microparticles were well wetted with the resin.

hazelnut shell microparticles, composite, Corylus avellana, strength, hardness

Müller, M., Valášek, P., Linda, M., Petrásek, S. (2018): Exploitation of hazelnut (Corylus avellana) shell waste in the form of polymer–particle biocomposite. Scientia Agriculturae Bohemica, 49, 53-59. DOI: 10.2478/sab-2018-09

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Drivers of informal sector participation of small and medium enterprise in Ghana

The informal sector of Ghana has been growing amidst the recent economic development in this country. The study investigated the drivers of informal sector participation by SMEs in Ghana and made use of a Chi-square statistical methodology to analyze the drivers of SME participation in the informal sector of Ghana. Analyses from the study showed that gender can be deemed as a driver for SME participation in the informal sector of Ghana. Gender was significant at 0.012 with registration of business enterprise and 0.055 with tax obligation of respondents. The educational level of SME operators had an impact on registration and tax obligation and therefore can be deemed as a driver of SME participation in the informal sector of Ghana. However, the level of education was insignificant to registration and tax obligation but had a strong correlation to these variables. The study also showed that women are more likely to participate in the informal sector of Ghana as compared to men and also that there is a high tendency of not paying tax among SME operators in the informal sector of Ghana. A very low educational level among SME participants was recorded with over 60% of the respondents not having any formal education. Based on the findings of the study, a country-wide research can be done to ascertain the socio-economic determinants of informal sector participation in Ghana. Also, the study highly recommends policies that can harness the usefulness of informal sector.

business, economic development, tax, education, economy, registration

Mintah, S,. Darkwah, S. (2018): Drivers of informal sector participation of small and medium enterprise in Ghana. Scientia Agriculturae Bohemica, 49, 60-67. DOI: 10.2478/sab-2018-10

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