Abstract

Blooming of cyanobacteria is a common problem of eutrophic water

bodies in Europe and worldwide and can cause severe problems with toxicity, taste

and odour of the water. Toxins produced by cyanobacteria (cyanotoxins) are structurally

diverse and their effects range from liver damage, including liver cancer, to

neurotoxicity and thus they may present a serious threat for drinking water safety.

Cyanobacterial blooms present major challenges for the management of rivers, lakes

and reservoirs and are predicted to cause even worse problems in the future due to

the climate change associated with global warming, increased availability of light to

phytoplankton and rising levels of atmospheric CO 2 . This paper presents the literature

review of occurrence, toxins (along with their effects on human health) and possibilities

of control of bloom-forming cyanobacteria.

Keywords

algal blooms, cyanobacteria, cyanobacterial control, cyanotoxins, Europe, freshwaters

Abstract

Experiments with invertebrates have recently gained increased attention

as a practicable substitute to traditional mammalian models in the study of host-bacterial

interactions. Using an invertebrate study model has a number of advantages over

traditional mammalian model including simple growth condition, short life-time, can

be easily maintained, infected without anesthesia and with a smaller extent of ethical

limitations. From a microbiological viewpoint, importance of anaerobic bacteria as

agents for various diseases remains an interesting field for research. The study of the

interaction between invertebrate model host and anaerobic bacteria therefore provides

insights into the mechanisms underlying pathogen virulence and host immunity and

complements or even compensates the use of mammalian model in assay for infectious

disease. This review offers to consider about the appropriate invertebrate model select

for the study of particular aspects of anaerobic bacterial pathogenesis.

Keywords

invertebrate model, anaerobic bacteria, virulence factors, disease

Abstract

Selenium (Se) and iodine (I) are essential elements for humans and

animals, while their essential role for plants has not been established yet. There is also

very little information about the interaction between selenium and iodine in plants.

The aim of our research was to determine the effect of different forms of Se, I and

their combinations on selected biochemical and morphological characteristics of the

kohlrabi sprouts ( Brassica oleracea L. var. gongylodes L.). Sprouts were grown from

seeds, which were soaked in different solutions of selenite, selenate, iodide, iodate

and their combinations. We measured the content of chlorophyll a and b , carotenoids,

anthocyanins, and UV-A and UV-B absorbing substances. We also measured potential

photochemical efficiency of photosystem II (PS II). At the end of the experiment the

weight and height of the sprouts were measured. In order to compare the results the

entire experiment was carried out twice. Different chemical forms of Se and I, and

combinations did not significantly affect the number of sprouts that germinated from

seeds. The various chemical forms of Se and I, and combinations differently affected

on the amount of pigments in the kohlrabi sprouts. Potential photochemical efficiency

of PS II was close to theoretical maximum 0.83.

Keywords

kohlrabi, sprouts, selenium, iodine

Abstract

The European blind cave salamander, Proteus anguinus, is a neotenic,

permanently aquatic amphibian with a very long life span, late sexual maturity, and

the ability to reproduce for at least 30 years. Proteus is considered to be vulnerable

species, and yet very little is known about its reproductive biology. The objective of

this study is to describe the detailed morphology of the testes of adult Proteus and

determine the maturation state of the gonads and gametogenesis with respect to body

size and seasonality. This research showed that testis size increases with adult male

body length, but the shape and meiotic condition of the testes are highly variable

and independent of the length of the specimen. The testis of Proteus has a simple

cystic type of organization in which cysts are enclosed in lobules, with synchronous

maturation of the germ cells within each cyst. Spermatogenesis progresses in a caudocephalic

direction within the testis, as in other salamanders, and appears to be seasonal,

despite the fact that Proteus is a cave animal living in stable environmental conditions.

Surprisingly, the testes of approximately one third of the specimens, regardless of

their morphology or meiotic condition, contained testis-ova located randomly among

groups of spermatogonia and spermatocytes. These testes-ova contained germinal

vesicles with lampbrush chromosomes, and thus correspond to primary oocytes. The

presence of testis-ova may be related to a sex-chromosome turnover involving X-Y

translocation that was recently discovered in Proteus .

Keywords

testis, morphology, spermatogenesis, proteus, Proteus anguinus

Abstract

We used a clearing and staining method for cartilage and bone to analyse

the pattern of ossification in the skeleton of the common European toad, Bufo bufo ,

a species with rapid larval development. We focused on the ossification of vertebrae,

pectoral and pelvic girdles, and limbs with an emphasis of the ossification in their distal

parts. We found that the cartilage primordia of the skeleton were formed by the end of

premetamorphosis (Stage 34). The first ossifications appeared in early prometamorphosis

(Stage 39) and occurred concurrently in the neural arches, diaphyses of proximal

elements of front and hind limbs, and in the proximal part of the ileum. The pectoral

girdle was still completely cartilaginous at this stage. Ossification intensifies during

prometamorphosis and gradualy progresses in a cranial - caudal direction along the

spine and from proximal to distal parts of the skeleton, as well as to the epiphyses of

the long bones. Fingers ossified in a posterio-anterior direction according to the main

limb axis. As in most other anurans, the skeleton of Bufo is almost completely ossified

by the end of the metamorphic climax (Stage 46). At this time, cartilage remains in the

dorsal midline of the spine, in the distal parts of transverse processes of the vertebrae,

the caudal part of the post-sacral region, as well as in the epiphyses, and carpals and

metacarpals of the limbs, and in the suprascapula and the pubis of the girdles. These

results show a conserved pattern of ossification in B. bufo common to other anurans

despite its rapid rate of larval development.

Keywords

skeleton, ossification, Bufo bufo , clearing and staining method for skeleton

Abstract

In the present study, we investigated lower secondary school student’s

interest and emotions regarding dissection in schools. Self-reported interest and emotions

of fear and disgust toward dissection were assessed. In addition to well-known

gender differences from prior studies, the author also assessed if age, participation

in home cooking of meat and fish or participation in the home slaughtering and

butchering of livestock has an effect on these mentioned dependent variables. The

results show, that situational interest was predominantly influenced by the students’

age. Older students displayed higher interest in school dissections. Individual interest

was influenced by grade, gender and by participation in home slaughtering. Emotions

concerning dissection were significantly influenced by gender. Situational interest was

predicted both by personal interest and negative emotions. From the results, it can be

concluded that participation in home cooking and home slaughtering of livestock has

no effect on students’ interest and emotions regarding dissection, which is somehow

contradictory to the statements of other authors who argue that repeated exposure to

dissections raises student’s interest and lowers negative emotions regarding dissections.

Perhaps spatial and temporal dimensions ought to be considered in addition to the

level of students’ involvement in such activities.

Keywords

animals, dissection, interest, emotions, secondary school students