Spiders are generalist predators that contribute to the control of pests in agroecosystems. Land use management determines habitats including refuges for hibernation and aestivation. The availability of shelters on the ground can be crucial for maintaining populations of spider within crops. We studied the effect of the number of stones on the surface of the soil on the spider community in selected olive groves in Trás-os-Montes (northeastern Portugal). The number of stones significantly influenced the overall diversity of spiders, abundance of immature individuals and abundance of ground hunters. Agricultural management practices aimed at the conservation of soil microhabitats such as hedgerows, stonewalls and stones on the ground should be promoted in order to maintain or increase the number of shelters for potential natural enemies of pests., Jacinto Benhadi-Marín, José A. Pereira, José A. Barrientos, José P. Sousa, Sónia A.P. Santos., and Obsahuje bibliografii
Faecal samples were collected from cats kept as pets (n = 120) and stray cats (n = 135) in Central Europe (Czech Republic, Poland and Slovakia) and screened for the presence of Cryptosporidium spp., Giardia intestinalis (Kunstler, 1882), Encephalitozoon spp. and Enterocytozoon bieneusi Desportes, Le Charpentier, Galian, Bernard, Cochand-Priollet, Lavergne, Ravisse et Modigliani, 1985 by PCR analysis of the small-subunit of rRNA (Cryptosporidium spp. and G. intestinalis) and ITS (microsporidia) genes. Sequence analysis of targeted genes revealed the presence of C. felis Iseki, 1979, G. intestinalis assemblage F, E. cuniculi Levaditi, Nicolau et Schoen, 1923 genotype II, and E. bieneusi genotype D. There was no correlation between the occurrence of detected parasites and sex, presence of diarrhoea or drug treatment (drug containing pyrantel and praziquantel). Compared to pet cats (7%), stray cats (30%) were statistically more frequently infected with protist parasites and overall may present a greater risk to human health., Martin Kváč, Lada Hofmannová, Ynes Ortega, Nikola Holubová, Michaela Horčičková, Marta Kicia, Lenka Hlásková, Dana Květoňová, Bohumil Sak, John McEvoy., and Obsahuje bibliografii
Nitrogen is an essential factor for normal plant and algal development. As a component of nucleic acids, proteins, and chlorophyll (Chl) molecules, it has a crucial role in the organization of a functioning photosynthetic apparatus. Our aim was to study the effects of nitrogen starvation in cultures of the unicellular green alga, Chlamydomonas reinhardtii, maintained on nitrogen-free, and then on nitrogen-containing medium. During the three-week-long degreening process, considerable changes were observed in the Chl content, the ratio of Chl-protein complexes, and photosynthetic activity of the cultures as well as in the ultrastructure of single chloroplasts. The regreening process was much faster then the degradation; total greening of the cells occurred within four days. The rate of regeneration depended on the nitrogen content. At least 50% of the normal nitrogen content of Tris-Acetate-Phosphate (TAP) medium was required in the medium for the complete regreening of the cells and regeneration of chloroplasts., É. Preininger, A. Kósa, Z. S. Lőrincz, P. Nyitrai, J. Simon, B. Böddi, Á. Keresztes, I. Gyurján., and Obsahuje seznam literatury
The specific features of the structural and functional organisation of the photosynthetic apparatus (PSA) were studied in wild halophytes representing three strategies of salt tolerance: euhalophyte Salicornia perennans, crynohalophyte Limonium gmelinii, and glycohalophyte Artemisia santonica. The sodium content in aboveground parts of the plants corresponded to the strategy of salt tolerance. The photosynthetic cells of the euhalophyte were large and contained a higher number of chloroplasts than those in other species. In contrast, the number of cells per a leaf area unit was lower in S. perennans as compared to cryno- and glycohalophytes. Thereupon, the cell and chloroplast surface area per leaf area unit declined in the following sequence: A. santonica > L. gmelinii > S. perennans. However, the large cells of euhalophyte contained chloroplasts of larger sizes with 4- to 5-fold higher chlorophyll (Chl) content per chloroplast and Chl concentration in chloroplast volume unit. Also, chloroplasts of S. perennans were characterised by the higher content of glyco- and phospholipids. Qualitative composition of fatty acids (FA) in lipids isolated from the chloroplast-enriched fraction was similar in all three species; however, the index of unsaturation of FA was higher in glycohalophyte A. santonica than those in two other species. Under natural condition, PSA of all three halophytes showed high resistance to soil salinity. The results indicated tolerance of PSII to the photodamage in halophytes. The high rate of electron transport through PSII can be important to prevent oxidative damage of PSA in halophytes under strong light and hight temperature in vivo. Thus, the strategy of salt tolerance is provided by both the leaf anatomical structure and the ultrastructure of photosynthetic membranes, which is determined in particular by the specific composition of lipids., O. A. Rozentsvet, E. S. Bogdanova, L. A. Ivanova, L. A. Ivanov, G. N. Tabalenkova, I. G. Zakhozhiy, V. N. Nesterov., and Seznam literatury
On the ventral tube of males of Onychiuroides granulosus (Stach, 1934) there is a male ventral organ, which consists of two groups of four setae that are thickened, slightly flattened and bent. All setae of the male ventral organ are inserted in a richly sculptured cuticle. At the base of each seta there are a few large cells (basal cells) that have large irregular nuclei that contain a large amount of heterochromatin. In the cytoplasm of the basal cells there are numerous mitochondria, ribosomes and a rich system of endoplasmic reticulum. The plasma membrane of the basal cells forms richly folded, deep invaginations, filled with a dense material, which also occurs in particular setae and on their surface. The present study indicates that the male ventral organ is secretory and does not confirm its previously suggested sensory function., Bożena Simiczyjew, Dariusz Skarżyński, Adrian Smolis, Romuald J. Pomorski, Marta Mazurkiewicz-Kania., and Obsahuje bibliografii
Identifying patterns with sufficient predictive power is a constant challenge for ecologists to address ecological problems related to species conservation, pollution or infectious disease control. During the last years, the amounts of parasitological studies in this sense increased, but they are still scarce in urban environments. The main aim of this study was to investigate if the helminth communities of urban rodents are structured within host assembly (compound community) or they are a result of random events occurring at each individual host scale (infracommunity). A total of 203 rodents belonging to four species, Rattus rattus (Linnaeus), Rattus norvegicus (Berkenhout), Mus musculus Linnaeus and the native Oligoryzomys flavescens (Waterhouse) and captured in different landscape units of the City of Buenos Aires (industrial-residential neighbourhoods, shantytowns and parklands) were analysed. The results showed that infracommunities could be grouped according to composition and relative abundances and that they respond to the structure of the host community. Thus, the component communities defined in this study could be identified as subsets of the compound community (rodent assemblage) and infracommunities (each host) as random samples within each one. Quantitative differences among component communities were denoted by comparing the infection levels of helminths described as central species. Therefore, infracommunities of R. norvegicus and O. flavescens were the most predictable because of the high abundance of the nematodes Heterakis spumosa Schneider, 1866 and Nippostrongylus brasiliensis (Travassos, 1914), and Stilestrongylus flavescens (Sutton et Durette-Desset, 1991), respectively. Several mechanisms contribute to complexity of the structure of parasite communities, where specific parasites, definitive and intermediate hosts, and environmental and anthropogenic factors all play a role in the dynamics of the compound community., Diego Hancke, Olga Virginia Suárez., and Obsahuje bibliografii
Phoridae (scuttle flies) are widely distributed, occur in many types of habitats and are ecologically versatile, which makes them an excellent bioindicator group for evaluating faunal diversity. The structure of scuttle fly communities was compared in two Mediterranean habitats in the Montseny Natural Park (Catalonia, Spain) that differ in vegetation and microclimate: beech forest and highland scrubland. 3684 male individuals belonging to 135 species of scuttle flies were identified. Scuttle flies were more abundant in beech forest than scrubland. Observed and estimated species richness were lower in scrubland than in beech forest, while diversity was similar in both habitats. Community evenness was greater in scrubland than beech forest. Therefore, the percentage of dominant and subdominant species was higher in scrubland than beech forest, while the percentage of rare species was higher in beech forest than scrubland. Scuttle fly species composition was significantly different in the two habitats, but it was similar among plots within the same habitat. Megaselia pectoralis (Wood, 1910) and Megaselia subpleuralis (Wood, 1909) were the dominant species in beech forest, while Megaselia pusilla (Meigen, 1830), Megaselia pumila (Meigen, 1830), Megaselia superciliata (Wood, 1910) and Megaselia diversa (Wood, 1909) were the dominant species in scrubland. Trophic specialization was higher in beech forest than scrubland. Saprophages were the dominant trophic group in beech forest, while fungivores and polyphages were dominant in scrubland. The high biodiversity of scuttle flies recorded in the Montseny Natural Park indicates that there is also a high diversity of other taxa there and that these Mediterranean mountains are of high conservation status., Carlos García-Romera, José A. Barrientos., and Obsahuje bibliografii