The aim of our in vitro studies was to understand the role of leptin in controlling proliferation, apoptosis, and protein kinase A (PKA) in human ovarian cells. We analyzed the in vitro effects of leptin (0, 1, 10 or 100 ng/ml) on the accumulation of proliferation-related peptides (PCNA, cyclin B1), apoptosis-associated peptide (Bax) and the intracellular signaling molecule PKA in cultured human granulosa cells using immunocytochemistry and Western immunoblotting. It was observed that leptin stimulated in a dose-dependent manner the accumulation of PCNA (at doses 1-100 ng/ml), cyclin B1 (at doses 10 or 100 ng/ml), Bax (at doses 10 or 100 ng/ml) and PKA (at doses 1-100 ng/ml) in cultured human ovarian cells. These observations suggest the ability of leptin to control directly human ovarian cell functions: proliferation, apoptosis, and intracellular messenger PKA., A. V. Sirotkin, M. Mlynček, A. V. Makarevich, I. Florkovičová, L. Hetényi., and Obsahuje bibliografii a bibliografické odkazy
A cyanobacterium containing phycobiliproteins with far-red acclimation was isolated from Pozas Rojas, Cuatro Ciénegas, México. It was named Leptolyngbya CCM 4 after phylogenetic analysis and a description of its morphological characteristics. Leptolyngbya was grown in far-red light. Sucrose-gradient analysis of the pigments revealed two different colored bands of phycobiliproteins. A band at 60% sucrose was a phycocyanin containing phycobilisome; at 35% sucrose, a new type of phycobiliprotein absorbed at 710 nm. SDS-PAGE revealed the presence of two types of core-membrane linkers. Analysis of the hydrophobic pigments extracted from the thylakoid membranes revealed Chl a, d, and f. The ratio of Chl f/a was reversibly changed from 1:12-16 under far-red light to an undetectable concentration of Chl f under white light. Cuatro Ciénegas, a place surrounded by the desert, is a new ecosystem where a cyanobacterium, which grows in farred light, was discovered., C. Gómez-Lojero, L. E. Leyva-Castillo, P. Herrera-Salgado,
J. Barrera-Rojas, E. Ríos-Castro, E. B. Gutiérrez-Cirlos., and Obsahuje bibliografické odkazy
The Southern Urals are an inspiring place for Czech naturalists. This paper provides basic information on this seldom visited region and describes the impressions of the two Czech biologists from their excursion to this place. The nature of the Southern Urals captivated them with its wildness, unrivalled in present-day Central Europe, its intrinsic order and the similarities with Central European nature. and Jan Roleček, Jan Losík.
Charakter krajiny je v oblasti centrálních Apenin již na první pohled výrazně různorodý. Dynamicky formovaný reliéf pokrývá pestrá mozaika vegetačních typů. Zdejší lesy jsou od dávných dob obhospodařované pařezinovým způsobem, což je typ managementu, který byl na území bývalého Československa běžný až do minulého století. Typicky šlo o dubové a dubohabrové lesy, jejichž biodiverzita dlouhodbě klesá. Návštěva a studium lesů centrálních Apenin poskytuje hodnotné souvislosti pro řešení problému klesající druhové diverzity v někdejších pařezinách střední Evropy., The landscape of the central Apennines is markedly diverse. Dynamically formed relief is covered by a mosaic of different vegetation types. For centuries, local forests are managed as coppices - type of management common in former Czechoslovakia up to last century. Biodiversity of these oak and oak-hornbeam forests gradually declines due to the abandonment of coppicing. Thus, a visit to the central Apennines and study of their forests provide a valuable insight into the problem of species diversity decline in the former coppices of Central Europe., and František Máliš, Roberto Canullo, Radim Hédl.
In Europe there are only a few species of the syrphid fly Microdon, which live in the nests of various genera of ants. For most of these rare flies, details of their biology, larval behaviour and relationships with their hosts are still not yet well known. In this paper we present data on the life cycle, feeding behaviour and growth pattern of Microdon myrmicae, a social parasite of Myrmica ants and compare it with two species of Maculinea butterflies similarly parasitizing Myrmica ant colonies. M. myrmicae has three larval instars and overwinters as a third instar. Eggs and 1st instar larvae are ignored by ants, which indicate that they are “chemically insignificant”. 2nd and 3rd instar larvae feed on small ant brood. M.myrmicae larvae grow rapidly from May to July and later in the year the host colony only serves as shelter for overwintering. Like Maculinea alcon, larvae of M. myrmicae are numerous in Myrmica nests and more numerous than those of Maculinea teleius. Since the larvae of Microdon feed on an abundance of young ant brood, they experience low level of scramble competition and although many may develop in an ant’s nest they have probably little effect on host colony fitness., Magdalena Witek ... [et al.]., and Obsahuje seznam literatury
Ichthyophthirius multifiliis Fouquet, 1876, a ciliate parasite, is a cosmopolitan and problematic parasite of cultured freshwater fish. Each geographical isolate of I. multifiliis has variations in life cycle timing under different abiotic water conditions, such as temperature and salinity. We assessed the effects of salinity and temperature on the development and the preferred settlement site of a temperate Australian isolate of I. multifiliis. The time until theront release was significantly different between each temperature; development time was longest at 5 °C with a mean time of 189 h and decreased to a mean time of 11.7 h at 30 °C. At 5 °C our isolate produced a mean of 267 theronts per tomont, which increased to a mean of 493 theronts at 25 °C and reduced to a mean of 288 theronts at 30 °C. Theront length showed an inverse relationship to temperature; mean length was 62 μm at 5 °C and 41 μm at 30 °C. Our isolate reproduced faster at all temperatures and a greater sensitivity to salinity than all reported profiles for temperate isolates. Parasite abundance was highest on the dorsal region of the fish. An accurate understanding of temperature-life cycle information and optimal region to sample for surveillance will aid in the development of specific management plans for the Australian isolate of I. multifiliis, facilitating the strategic timing of treatments., James M. Forwood, James O. Harris, Matt Landos, Marty R. Deveney., and Obsahuje bibliografii
A new haemogregarine species Hepatozoon affluomaloti sp. n. is described from erythrocytes in the peripheral blood of crag lizards Pseudocordylus melanotus (Smith) and Pseudocordylus subviridis (Smith) (Sauria: Cordylidae) from mountainous regions in the Eastern Free State, South Africa. This species can be distinguished from all other congeners based on its large size, staining properties and life cycle development in its vector, Culex (Afroculex) lineata (Theobald) (Diptera: Culicidae). Mature gamonts stain mostly uniformly pinkish-purple with Giemsa, sometimes containing darker azurophilic granules anterior and posterior to the nucleus. The reflexed posterior extremity of the gamont stage sometimes stains slightly deeper purple and the nucleus is dense and placed in the posterior third of the parasite body. Merogonic stages of this haemogregarine occur in the liver tissues of P. melanotus with dizoic meronts. Macromeronts contains 2-7 macromerozoites and micromeronts contains 9-24 micromerozoites. Sporogonic developmental stages found in the proposed final host and vector, C. lineata, include large oocysts, measuring 54 × 48 µm on average. Sporulating oocysts with 8 nuclei are present in mosquitoes 6-7 days post-feeding on infected lizards. Sporocysts with mature sporozoites measure 31.0 × 21.8 µm on average and each contains 2-8 large sporozoites. It is suggested that transmission of infective sporozoites is achieved through predation of lizards on mosquitoes., Johann Van As, Angela J. Davies, Nico J. Smit., and Obsahuje bibliografii
This paper describes previously unreported lateral cuticle splits occurring during the moulting of larvae of the leaf-miners Pachyschelus laevigatus (Say, 1839) (Coleoptera: Buprestidae) and Cameraria sp. (Lepidoptera: Gracillariidae). In these species the cuticle does not split dorsally during the larval/larval moults as in most insects, but laterally, thus permitting the larva to leave its exuviae sideways rather than vertically. This previously overlooked phenomenon is hypothesized to have evolved independently in both taxa and is an adaptation to life in the vertically limited space of their mines and, therefore, might be found in other organisms confined to similar conditions. The exuvial split in the larva to pupa moult of Cameraria sp. taking place inside a relatively tick and firm cocoon is, however, of the regular dorso-medial type, and, therefore, two different successive types of moult occur within a single ontogenesis. For comparative purposes the common dorsal exuvial split is described and illustrated for the leaf-mining larvae of Profenusa alumna (Hymenoptera: Tenthredinidae), Sumitrosis rosea (Coleoptera: Chrysomelidae) and the free-living Satonius fui (Coleoptera: Torridincolidae)., Vasily V. Grebennikov., and Obsahuje seznam literatury