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
In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notocotylus noyeri (Joyeux, 1922) by means of transmission electron microscopy. The mature spermatozoon of N. noyeri exhibits the general pattern described in the majority of digeneans: two axonemes of the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondria, parallel cortical microtubules, spine-like bodies and ornamentation of the plasma membrane. The glycogenic nature of the electron-dense granules was evidenced applying the test of Thiéry. The ultrastructural features of the spermatozoon of N. noyeri present some differences in relation to those of the Pronocephalidea described until now, but confirm a general pattern for the Notocotylidae, namely a spermatozoon with two mitochondria and an anterior region with ornamentation of the plasma membrane associated with spine-like bodies. The posterior extremity of the spermatozoon exhibits only some microtubules after the disorganisation of the second axoneme. The present study confirms that some ultrastructural characters of the sperm cell such as the presence or absence of lateral expansions, the number of mitochondria and the morphology of both anterior and posterior spermatozoon extremities are useful for phylogenetic purposes within the Pronocephaloidea. Thus, unlike notocotylids, pronocephalids exhibit external ornamentation and a lateral expansion in the anterior spermatozoon region. Moreover, notocotylid spermatozoa present two mitochondria, whereas pronocephalid spermatozoa exhibit a single mitochondrion. Finally, pronocephalids are characterised by a type 2 posterior spermatozoon extremity, whereas notocotylids exhibit a type 3 posterior spermatozoon extremity., Papa Ibnou Ndiaye, Jordi Torres, Catarina Eira, Vladimir V. Shimalov, Jordi Miquel., and Obsahuje bibliografii
The present study attempts to determine how some physiological and reproductive functions of olive tree (Olea europaea L., cv. Koroneiki) respond to enhanced UV-B radiation or heat. Enhanced UV-B radiation was applied to (1) three-year-old potted plants in an open nursery (corresponded to ca. 16% ozone depletion), and (2) in vitro cultured pollen samples (220 μmol m-2 s-1, PAR = 400-700 nm + UV-B at 7.5, 15.0, or 22.5 kJ m-2 d-1). Potted olive plants were also subjected to high temperature (38 +- 4°C) for 28 h to mimic heat levels regularly measured in olive growing areas. A significant effect of UV-B on photosynthetic rate was observed. However, enhanced UV-B radiation did affect neither chlorophyll nor carotenoid content, supporting previous reports on hardiness of the photosynthetic apparatus in olive. Increased superoxide dismutase activity was observed in UV-B-treated olive plants (+ 225%), whereas no effect was found in the plants under heat stress. Neither UV-B and nor heat did affect H2O2 accumulation in the plant tissues. However, the same treatments resulted in enhanced lipid peroxidation (+ 18% for UV-B and + 15% for heat), which is likely linked to other reactive oxygen species. The increased guaiacol peroxidase activity observed in both treatments (+ 32% for UV-B and + 49% for heat) is related to the defense against oxidative membrane damage. The observed reduction in pollen germination (20-39%) and tube length (11-44%) could have serious implications on olive yields, especially for low fruit-setting cultivars or in years and environments with additional unfavorable conditions. UV-B and heat effects described here support the hypothesis that plant response to a given stressor is affected by the overall context and that a holistic approach is necessary to determine plant strategies for climate change adaptation., G. C. Koubouris, N. Kavroulakis, I. T. Metzidakis, M. D. Vasilakakis, A. Sofo., and Obsahuje bibliografii
Various types of artificial ant nests (formicaries) are described. These include simple laboratory types to more complex formicaries whose esthetic design is suitable for flat interiors. Formicaries facilitate not only the observation of natural ant behaviour inside a nest, but also of the remarkable practices used by young queens to appropriate the nest of a host ant species. In such equipment it is even possible to arrange a predatory raid by slave-making ants and observe their behaviour inside the attacked nest. Such observations would not have been possible in natural conditions. and Pavel Amcha.