Two closely related parasitoid wasp species with different host specificities were used for experimental studies on the biology of host finding, a crucial element of parasitoid life history: The habitat and host specialist Nasonia vitripennis and the habitat and host generalist Dibrachys microgastri (Chalcidoidea: Pteromalidae). The host finding parameters tested included reaction to olfactory cues, aspects of locomotor activity, ability to locate hidden hosts and day-night-activity. The results revealed distinct interspecific differences that match the respective host and habitat ranges of the two species. In N. vitripennis host finding is dominated by olfactory reaction to hosts and host habitat, i.e., fly puparia and birds' nests. In D. microgastri olfactory cues have only a minor role. Its host finding is characterized by rapid searching at random. Both species are able to locate hidden hosts. Although still incomplete, these insights into host finding by two parasitoid species with different life history strategies indicate they can be characterized by specific combinations of behavioural host finding features. and Ralph S. Peters.
This article refers to the rich vegetation on the rocky slopes along the Achensee (Tyrol, Northern calcareous Alps, Karwendelalpen) described by Professor Anton Kerner 150 years ago. The vegetation today is much less diverse, the subalpine species abundant in the last centuries are absent while the species of mixed mountainous forest prevail. The abundance of the Heather (Calluna vulgaris), which was not mentioned by A. Kerner, may indicate acidification due to acid rain. And the retreat of subalpine species may indicate the on going change to a warmer climate. and Jarmila Kubíková.
Retroviry jsou jednoduché RNA viry, které se vyznačují schopností přepsat svou RNA do dvouřetězcové DNA a tu stabilně začlenit do genetické informace hostitelské buňky. Tato jejich vlastnost stojí za latencí viru HIV, která v současnosti představuje hlavní překážku v úspěšné léčbě HIV pozitivních pacientů. Na druhou stranu lze této jejich vlastnosti využít pro přenos genetické informace za účelem léčby četných chorob s využitím přístupů genové terapie. Pro tyto účely je však potřeba retroviry vybavit sekvencemi, které zajistí jejich stabilní aktivitu a ochrání je před umlčením., Retroviruses are simple RNA viruses, which exhibit an ability to convert their RNA to double-stranded DNA and introduce it into the host cell genome. This ability stands behind the HIV latency phenomenon - a major obstacle to successful therapy. On the other hand, this capability can be utilized for the transfer of genetic information in order to cure various diseases using gene therapy approaches. To achieve successful therapy, the retroviruses need to be equipped with sequences protecting them from silencing, thus stabilizing their activity., and Filip Šenigl.
A large outbreak of haemolytic uraemic syndrome and bloody diarrhoea caused by the pathogenic E. coli strain in Germany in 2011 has increased attention to foodborne diseases – bacterial infections linked to the consumption of fresh produce. Since the early 1990s, evidence is emerging that en - teropathogenic bacteria have the ability to grow and persist on crop plants for prolonged periods of time, including until harvest, and to be the carrier of illness. and Václav Kůdela.
Nowadays, increasing attention is being paid to the biological significance of UV- -reflecting patterns exposed on the outer surfaces of various organisms. UV radiation plays an important role in the communication of many species of organisms. Here we give a brief overview of the biological functions of UV reflectance in some groups of invertebrates. Special attention is paid to the role of UV reflectance in sexual selection, foraging strategies, and the evolution and ecology of a species in general. and Pavel Pecháček, David Stella, Karel Kleisner.
Mnoho skupin živočichů disponuje zrakem citlivým na tzv. ultrafialové světlo. Jednou z takových skupin jsou i různí opylovači, kteří nám dobře známé květy mohou vidět v trochu odlišných barvách, než my. Na květech rostlin totiž často existují vzory patrné pouze v ultrafialové části spektra, které jsou pro člověka neviditelné. V první části seriálu o výskytu a významu těchto vzorů u rostlin se zabývá historií odhalování citlivosti živočichů na ultrafialové světlo, přibližuje otázky, jak funguje zrak a jakým způsobem ultrafialové zbarvení na povrchu organismů vzniká., The vision of many animal groups is sensitive to the so-called ultraviolet (UV) light. These groups include various pollinators, which may see flowers that are quite familiar to us in a different coloration. That is because flowers often feature patterns visible only in the UV part of the spectrum, and thus invisible to humans. This series deals with the occurrence of such patterns and their significance for plants. The first part recounts the history of discovering the sensibility of animals to UV light, expounds on the way how vision works, explains the origin of UV coloration on organismal surfaces., and Pavel Pecháček.
Význam ultrafialových znaků v životě různých organismů byl dlouho opomíjen především z toho důvodu, že UV paprsky jsou pro lidský zrak za normálních okolností neviditelné. Jedna z možností, jak si můžeme ultrafialovou podobu živočichů či rostlin zviditelnit, je použití speciálně upraveného klasického či digitálního fotoaparátu. Druhý díl seriálu o ultrafialových vzorech na květech rostlin se zabývá vývojem techniky záznamu UV podoby různých organismů a popisem získávání fotografií, které doprovázejí tento text. Druhá část článku je věnována vybraným druhům našich nejběžnějších rostlin a charakterizaci jejich ultrafialových znaků., The significance of UV characteristics for the life of various organisms has been neglected for a long time. It stems mainly from the fact, that under normal circumstances, UV rays are invisible to the human eye. One of the ways to make the UV appearance of animals or plants visible is to use a specially adjusted classic or digital camera. This second paper deals with the UV patterns on flowers. It focuses on the development of techniques which allow us to capture the UV appearance of various organisms, and provides a methodology with which the accompanying photos were taken. The article also presents selected species of common native plants, with a description of their UV characteristics., and Pavel Pecháček.
The last part of this series about UV characters on plant flowers presents UV images of several other common plant species native to the Czech flora. Attention is also paid to the possibility of using herbarium material for research into the UV characters of plants. The article summarizes recently discovered knowledge along with the evolutionary and ecological factors behind the emergence and significance of UV characters on plant flowers, particularly their role in the communication of pollinators. and Pavel Pecháček.
A new microsporidian species of the genus Glugea Thélohan, 1891 parasitising the marine teleost fish Cephalopholis hemistiktos Rüppell, collected from the Red Sea in Saudi Arabia, is described on the basis of microscopic and molecular procedures. Spherical and whitish xenoma were observed adhering to the intestinal wall. The numerous spores contained within these xenoma, were ovoid to pyriform and measured 4.3-6.0 µm (5.1 µm) in length and 1.8-2.9 µm (2.2 µm) in width. The spore's wall was composed of two thick layers, which were thinner in the area contacting the anchoring disk. The latter appeared at the spore's anterior pole, in an eccentric position to the longitudinal axis. A lamellar polaroplast surrounded the uncoiled portion of the polar filament projected to the basal region of the spore, giving rise to 26-29 turns with winding from the base to the anterior zone of the spore. The posterior vacuole, located at the spore's posterior pole, and surrounded by the polar filament coils, was irregular and composed of light material. Molecular analysis of the rRNA genes, including the ITS region, was performed using maximum parsimony, neighbour-joining and maximum likelihood methods. The ultrastructural features observed, combined with the phylogenetic data analysed, suggest this parasite to be a new species of the genus Glugea. This is the first species of this genus to be reported from Saudi Arabia and is herein named Glugea nagelia sp. n., Abdel-Azeem S. Abdel-Baki, Saleh Al-Quraishy, Sónia Rocha, Mohamed A. Dkhil, Graça Casal, Carlos Azevedo., and Obsahuje bibliografii
Using scanning and transmission electron microscopy, ultrastructure of the anterior organ and posterior funnel-shaped canal of Gyrocotyle urna Wagener, 1852 (Cestoda: Gyrocotylidea) from ratfish, Chimaera monstrosa (Holocephali), was studied for the first time. The proper anterior organ is localised at a short distance (about 170 µm) from an apical pore surrounded by a receptor field, whereas its distal end is marked by a muscular sphincter. The tegumental surface of this organ is covered with short filitriches of irregular length; large area of muscle layers traverse beneath the tegumental layer. The funnel-shaped canal of G. urna (2.5-3.0 mm long) is a specialised, muscular part of the posterior attachment organ; it opens on the rounded elevation on the dorsal body surface. The tegumental layer bears conical sclerite-like structures (up to 1.5 µm long). It produces electron-dense bodies that are transported into a canal lumen and surrounded thick muscle area mixed with numerous nerve fibres. The present ultrastructural study of G. urna indicates that gyrocotylideans share some ultrastructural characters of the anterior organ with spathebothriidean cestodes with a single anterior attachment sucker-like organ. In contrast, the unique posterior rosette attachment organ with funnel-shaped canal of the Gyrocotylidea resembles the haptor of polyopisthocotylean monogeneans in its position at the posterior end of the body and presumed origin. The above-mentioned features add more clarity to support the basal position of the Gyrocotylidea Poche, 1926 among cestodes. In addition, they also indicate a possible relationship of gyrocotylidean ancestors with monogeneans., Larisa G. Poddubnaya, Roman Kuchta, Glenn A. Bristow, Tomáš Scholz., and Obsahuje bibliografii