Abstract

Slovenia with its diverse environment is home to more than 2400 fungal species out of which especially many macromycetes have for millennia been used worldwide as natural remedies. These species of mushrooms were in the past picked from the nature, but today can be cultivated as fruiting bodies or fungal biomass on different substrates. They possess immunomodulating, antiviral, antibacterial and anticancer activities and can be used against allergies, dementia, Alzheimer disease and in many other diseases. They represent a vast potential as natural remedies with no or very little adverse effects and can be processed into food supplement or further developed into medicines. These mushrooms are a natural treasure, which enables us to be more self-sufficient if we cultivate them for medical and certain species for nutritional purposes as well.

Keywords

medicinal mushrooms, Slovenia, polysaccharides, cancer, natural remedies, endangered fungi

Abstract

Strigolactones were first discovered as rhizosphere signals by which parasitic weeds detect the presence of host plant species. It was later recognized that they play a critical role in facilitating the formation of arbuscular mycorrhiza (AM), symbiosis with fungi, crucial for the acquisition of plant nutrients in over 80% of land plant species. Recently, strigolactones have also been shown to participate in regulation of several plant developmental processes. They are involved in the control of apical dominance (shoot branching), root development, nodulation, etc.. The paper presents the role of strigolactones in development of AM and their implication in other physiological processes. It discusses a possible role of strigolactones as integrators of the root-to-shoot balance, nutrient acquisition, and resource allocation.

Keywords

symbiosis, development, apical dominance, auxin transport

Abstract

This paper reports a study of the strategies in Norway spruce ( Picea

abies (L.) Karst.) and European beech ( Fagus sylvatica L.) for coping with enhanced

UV-B radiation. Trees, as plants in general, possess diverse systems which respond

to UV-B radiation. Changes in physiology, biochemistry and morphology have been

observed in trees under enhanced UV-B radiation. The efficiency of trees’ UV-B protective

systems depends on plant characteristics and state of development as well as

can be correlated with the UV-B dose and the environmental conditions. The two tree

species were exposed outdoors to enhanced UV-B simulating 17% ozone depletion

for three years during which time, selected parameters were monitored. Selected

physiological parameters were monitored three times a year on beech leaves and

three needle age classes of spruce. Spruce and beech exhibited great variability in the

amounts of chlorophyll, methanol-soluble UV-B and UV-A absorbing compounds,

and optimum quantum yield of photosystem II. The effects of UV-B radiation also

varied with needle and leaf development stage and interaction with environmental

conditions. Enhanced UV-B radiation triggered responses in both trees and a reduced

negative effect of UV-B radiation on spruce photochemical efficiency was observed

during prolonged drought. The results show high UV-B tolerance of both tree species

and indicate the complexity of plant response to UV-B, involving multilevel interactions

with environmental factors and thus emphasizes the necessity of long-term

investigations on trees in a natural ecosystem.

Keywords

Picea abies, Fagus sylvatica , UV-B radiation, long-term field experiment

Abstract

Exoskeletal cuticle of crustaceans is a chitinous matrix, produced apically by epidermis and stiffened by sclerotization and calcification. Embryos of terrestrial isopod crustacean Porcellio scaber develop within the female brood pouch, marsupium, and after hatching larvae mancae continue their development in the marsupium

for another week. This study was performed to reveal at the histochemical level whether the exoskeletal cuticle of marsupial mancae is already calcified. Fifteen different procedures of histochemical staining with alizarin red S (ARS), established for calcified tissue localization primarily in vertebrate histology, were evaluated on mancae and adult P. scaber specimens. The best differential staining of the exoskeletal cuticle was obtained with neutral buffered formaldehyde fixation, followed by paraffin sections staining with ARS 1 (pH 9) or ARS 2 (pH 6.4) or ARS 3 (pH 4.8) solution. Clear differential staining was achieved also in cryosections of formaldehyde fixed samples, stained with ARS 1 solution (pH 9). Our results suggest that prominent calcification of exoskeletal cuticle is present during postembryonic development of P. scaber mancae in the marsupium. Exoskeleton hardening is likely important also for body movements, that we observed in mancae before they were released from marsupium. The proposed procedures of ARS method are presumed to be applicable for histochemical studies of other calcified chitinous matrices.

Keywords

calcification, histochemistry, larval development, terrestrial isopods, Crustacea

Abstract

The new biology curriculum introduced the teaching of mitosis to 13- and 14-year-olds students in Slovenia. Mitosis is a challenging topic for this age. In our study, we enrolled a sample group of 95 students to check if the method of teaching mitosis first described by Danieley (1990) could be effective for students of this age. Prior to the survey, the students had not yet dealt with the division of cells; most of them did not even know that all living organisms are made of cells. The results show that this method is effective; enrolled students used logical reasoning and were thus able to understand how the events in the cell cycle and the process of mitosis follow

one another. The majority of students correctly arranged 15 drawings presenting the stages of the cell cycle after the lesson, and their knowledge retention was satisfactory. Incorrect placements of drawings did not show any typical mistakes in students thinking about the cell cycle that should create specific concerns for the biology teachers.

Keywords

mitosis, cell cycle, understanding, biology, 13-year-olds, 14-year-olds

Abstract

Expansins are a group of plant cell wall loosening proteins. In animals, functional expansin (EXPB1) has been discovered in the golden potato cyst nematode Globodera rostochiensis . In plant-parasitic nematodes expansins act as the parasitism factors or effectors. Molecular variability of another expansin ( exp B2) gene was evalua ted

in diverse populations of the G. rostochiensis . 3D modelling of GR-EXPB2 protein sequences revealed variants with different tertiary protein structure. Superimposing PDB structures of the protein model of common type protein with two longer variants revealed difference in position of one loop in the two longer proteins. All longer GREXPB2

variants originated from South America.

Keywords

Cell wall degradation, Globodera rostochiensis, effectors, expansin, parasitism factor, plant-parasitic nematode, potato cyst nematode, 3D structure