The Implication of Early Chromatin Changes in X Chromosome Inactivation

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Morphological details of microorganisms revealed by RCH-microscopy at high magnification —a ready-to-use adaptation of a light microscope

RCH-microscopy (Relief Contrast after Hostounsky) is a new method of optical microscopy in transmitted light developed withLambda Ltd., Prague. This method was used to study bacteria, fungi including yeasts and algae at high magnification. The equipment provides a three-dimensional image of high contrast and resolution. The results of these microscopic observations can be used for both morphological (taxonomical) and ecological studies of microorganisms.     

The chemical composition of the meat of fat dormice (<Emphasis Type="Italic">Glis glis</Emphasis> L.)

The fat dormouse (Glis glis) is a traditional game species in the Republic of Croatia. Although today the fat dormouse is not frequently caught as game, it is still a source of animal protein in human nutrition in certain rural areas of Croatia. In this paper the chemical analysis of fat dormouse meat is presented. The average values for the quantity of water, fat, protein and ash in dormouse meat are comparable with the chemical composition of the meat of rabbits and brown hares, except for the important fact that rabbit and hare meat contains a greater quantity of fat on average. According to our results, the meat of fat dormice can be categorised as dietary food, characterised by a small percentage of fat (mean 2.83%) and a high amount of protein (mean 21.01%).     

Formin homology 2 domains occur in multiple contexts in angiosperms

Background  

Involvement of conservative molecular modules and cellular mechanisms in the widely diversified processes of eukaryotic cell morphogenesis leads to the intriguing question: how do similar proteins contribute to dissimilar morphogenetic outputs. Formins (FH2 proteins) play a central part in the control of actin organization and dynamics, providing a good example of evolutionarily versatile use of a conserved protein domain in the context of a variety of lineage-specific structural and signalling interactions.     

The Effects of Growth Regulators on Flowering of Chenopodium murale Plants in vitro

In vitro culture of Chenopodium murale L. (ecotype 197) green and herbicide SAN 9789 - treated "white" plants was established and the effects of benzylaminopurine (BAP), indole-3-acetic acid (IAA) and gibberellic acid (GA₃) on growth and flowering were tested. Green plants did not flower on glucose free media, while 17 % of plants flowered on 5 % glucose-containing medium. SAN 9789 (10^–5 M) inhibited growth and flowering. BAP and IAA (0.1 – 5 mg dm^–3) also inhibited growth and flowering of green and "white" plants. GA₃ (10 mg dm^–3) stimulated leaf development in green plants, but had no significant effect on "white" plants, and stimulated flowering of green (41 %) and "white" (33 %) plants.     

A mechanism for the establishment of polar cell morphology based on the cytoskeleton-derived forces exerted on the cell boundary

A mechanism for the establishment of polar cell morphology is presented, based on the internal forces that the cytoskeletal structures exert on the cell boundary. Cell shapes are determined by postulating that they correspond to the minimum of the total energy of the system, which is the sum of the bending energy of the cell boundary and the potential energies of the involved forces. Axisymmetrical cell shapes are considered, and it is assumed that the cytoskeletal structures exert an extensional axial force and are involved in controlling the area of the cell boundary. The dependence of cell shapes on the axial force is presented for different values of this area. The results show that, at increasing axial force, the cell undergoes a discontinuous transition from an oval shape, exhibiting an equatorial mirror symmetry into a polar shape. The proposed mechanism is related to previously documented specific effects of microtubule- and actin-modifying drugs on polar shapes of developing isolated retinal photoreceptor cells. Received: 28 January 1998 / Revised version: 25 July 1998 / Accepted: 29 July 1998     

A study of rheological and molecular weight properties of recycled polysaccharides used as thickeners in textile printing

Polysaccharide thickeners (alginate, carboxymethylated guar gum and carboxymethylated cellulose) used for the preparation of printing pastes, were recycled from printing paste residues and from wastewater concentrates, which were separated by ultrafiltration technique from wastewater after screen printing of cotton with reactive dyes. Concentrated aqueous polysaccharide solutions were studied via rheological measurements under steady and oscillatory shear conditions. Molecular weight averages and molecular weight distribution of thickeners were determined by size exclusion chromatography.A satisfactory fitting of viscosity data is obtained with the Cross equation and mechanical spectra are described with satisfactory approximation with the Friedrich–Braun model. The obtained parameters enable a quantitative interpretation of the changes in rheological properties. Moderate changes produced by thickener recycling on the shear-thinning and viscoelastic behaviour of polymers are a direct result of changes in molecular weight averages (MWA) and molecular weight distribution (MWD).     

Maximum radius of carbon dioxide baited trap impact in woodland: implications for host-finding by mosquitoes

CDC traps were used to determine the maximum radius of carbon dioxide attraction within forest habitat (a forest plant community with Carpino betuli-Quercetum roburis). A central CDC trap with dry ice (CO₂) was set as the source of attractant (Ck). Around Ck trap two circles (A and B) of CDC traps without attractants were placed. Circle A was constituted of 6 CDC traps and Circles B with 12 CDC traps. Radius from Circle A and B to the Ck trap were used to determine CO₂ maximum range. During the experiment, the average emissions of CO₂ were 0.08 to 0.1 g s^?1. Regarding the data, optimal radius attraction where CO₂ was affected on mosquitoes was between 55 and 70 m from the source. Results propose that the distance between traps should be greater than 140 m, to ensure the absence of bias by each of the traps. Changes in CO₂ maximum concentration and wind velocity directly affected the catch of different species. The number of Ochlerotatus sticticus collected was positively correlated with wind speed.     

Free radical–scavenging activity and DNA damaging potential of auxins IAA and 2‐methyl‐IAA evaluated in human neutrophils by the alkaline comet assay

Auxins, of which indole‐3‐acetic acid (IAA) is the most widespread representative, are plant hormones. In addition to plants, IAA also naturally occurs in humans in micromolar concentrations. In the presence of peroxidase, indolic auxins are converted to cytotoxic oxidation products and have thus been proposed for use in gene‐directed enzyme/prodrug tumor therapy. Since data on the genotoxicity of IAA and its derivatives are not consistent, here we investigate the early DNA damaging effects (2‐h treatment) of the auxins, IAA, and 2‐methyl‐indole‐3‐acetic acid (2‐Me‐IAA) by the alkaline comet assay and compare them with their free radical–scavenging activity measured by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay. Human neutrophils are chosen as the test system since they possess inherent peroxidase activity. The results of the comet assay indicate an increase in DNA damage in a dose‐dependent manner up to 1.00 mM of both auxins. Generally, IAA applied in the same concentration had greater potential to damage DNA in human neutrophils than did 2‐Me‐IAA. The genotoxicities of the two examined auxins are negatively correlated with their antioxidant activities, as measured by the DPPH assay; 2‐Me‐IAA showed a higher antioxidant capacity than did IAA. We assume that differences in the molecular structure of the tested auxins contributed to differences in their metabolism, in particular, with respect to interactions with peroxidases and other oxidative enzymes in neutrophils. However, the exact mechanisms have to be elucidated in future studies. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:165–173, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20323     

Development of the ethmoidal structures of the endocranium in Discoglossus pictus (Anura: Discoglossidae)

We use histological techniques and computer‐aided three‐dimensional reconstructions made from serial histological sections to describe the ontogeny of the ethmoidal endocranium of discoglossid frog Discoglossus pictus. We identify a pattern of development for the suprarostral cartilage that differs from previous findings and probably represents the ancestral anuran pattern. The nasal cartilages, including the inferior prenasal cartilage, are de novo adult structures. The only larva‐derived structures of the adult nasal capsules are the posterior aspects of the solum nasi and septum nasi. We also identify patterns of development for the ethmoid plate and postnasal wall that occur during early in ontogenesis. These patterns are associated with development events during metamorphic climax. The pattern of timing of chondrification of the anterior nasal cartilages more closely coincides with that of the neobatrachian species than that recorded for the pelobatid frog Spea. In addition, this study supports a sister taxon relationship between Discoglossus and Alytes. J. Morphol. 271:1078‐1093, 2010. © 2010 Wiley‐Liss, Inc.