Growth and biomass allocation of sweet flag (Acorus calamus L.) under different nutrient conditions

Hydrobiologia - The antropogenically-induced process of eutrophication is accompanied by changes in the structure and function of the whole wetland ecosystem. Since the shift in a species ability...     

Enhanced accumulation of cadmium in Linum usitatissimum L. plants due to overproduction of metallothionein α-domain as a fusion to β-glucuronidase protein

As most cultivars of flax and linseed (Linum usitatissimum L.) are capable of accumulating cadmium (Cd), they are suitable candidates for phytoextraction of the metal from contaminated soils. In an attempt to enhance the phytoextraction capacity of L. usitatissimum through overproduction of an efficient heterologous Cd-binding peptide, we engineered linseed breeding line AGT 917 to constitutively express genetic fusion of α-domain of mammalian metallothionein 1a (αMT1a) and β-glucuronidase gus gene under the control of CaMV 35S promoter. An improved transformation protocol was developed, which involved co-cultivation of AGT 917 hypocotyl segments with partially removed epidermis with Agrobacterium suspension for 10 min in the presence of 200 mg l^?1 cellulase. The enzyme treatment increased the transformation efficiency (TE) 1.6-fold as compared to agroinfection without cellulase. Less pronounced impact on TE exerted 100 mg l^?1 acetosyringone, increasing TE 1.3-fold. When tested in soils amended with Cd at 20 and 360 mg kg^?1, the mature αMT1a::gus plants accumulated more Cd than parental AGT 917: the stem Cd concentrations in the best performing αMT1/2 line were 3.3- and 1.9-fold higher, respectively. Moreover, hypocotyl explants of αMT1/2 line showed 1.7-fold higher biomass than those of AGT 917 on media containing 15 mg Cd l^?1, indicating that αMT1a::gus did confer higher Cd tolerance to engineered plant. Overproduction of metal-binding peptides thus appears to be a viable strategy for the production of L. usitatissimum with improved phytoremediation capacity.     

Predictive and prognostic significance of tumour subtype,SSTR1-5 and e-cadherin expression in a well-defined cohort of patients with acromegaly

In somatotroph pituitary tumours, somatostatin analogue (SSA) therapy outcomes vary throughout the studies. We performed an analysis of cohort of patients with acromegaly from the Czech registry to identify new prognostic and predictive factors. Clinical data of patients were collected, and complex immunohistochemical assessment of tumour samples was performed (SSTR1-5, dopamine D2 receptor, E-cadherin, AIP). The study included 110 patients. In 31, SSA treatment outcome was evaluated. Sparsely granulated tumours (SGST) differed from the other subtypes in expression of SSTR2A, SSTR3, SSTR5 and E-cadherin and occurred more often in young. No other clinical differences were observed. Trouillas grading system showed association with age, tumour size and SSTR2A expression. Factors significantly associated with SSA treatment outcome included age, IGF1 levels, tumour size and expression of E-cadherin and SSTR2A. In the group of SGST, poor SSA response was observed in younger patients with larger tumours, lower levels of SSTR2A and higher Ki67. We observed no relationship with expression of other proteins including AIP. No predictive value of E-cadherin was observed when tumour subtype was considered . Multiple additional factors apart from SSTR2A expression can predict treatment outcome in patients with acromegaly.     

Influence of agricultural management form on the species structure of harvestman (Opiliones) communities

The paper is aimed at evaluation of the influence of two different agricultural management forms on harvestman (Opiliones) communities structure in relation to the optimization of land use on the model territory of Agricultural Cooperative (AC) Očová (Central Slovakia). The research was carried out using pitfall trapping through growing seasons from 2005 to 2007. Harvestmen were captured at four pairs of sites (8 sites in total). For each pair of sites the cultivation of the same crop with application of two different forms of agricultural management (conventional form and sustainable form with basic sustainable agro-environmental scheme) was characteristic. In total, 667 individuals of 8 species of the Phalangiidae family were captured during the research. The research results confirm the influence of management form on the structure of harvestman communities only partially. The obtained data indicate that the management form plays a significant role, especially in such agrocoenoses, in which the same crop is cultivated for several years (e.g., sites with alfalfa or permanent lawn), i.e., on the sites without ploughing or use of other similar agrotechnical measures. In these cases, the sites with the sustainable agro-environmental scheme showed higher diversity and equability of harvestman communities than the sites with the conventional form of agrotechnical management. Harvestman communities structure on sites with crop rotation and repeated ploughing was more influenced by additional factors than by the agricultural management form.     

Modulation of the antagonistic properties of an insulin mimetic peptide by disulfide bridge modifications

Insulin is a peptide responsible for regulating the metabolic homeostasis of the organism; it elicits its effects through binding to the transmembrane insulin receptor (IR). Insulin mimetics with agonistic or antagonistic effects toward the receptor are an exciting field of research and could find applications in treating diabetes or malignant diseases. We prepared five variants of a previously reported 20-amino acid insulin-mimicking peptide. These peptides differ from each other by the structure of the covalent bridge connecting positions 11 and 18. In addition to the peptide with a disulfide bridge, a derivative with a dicarba bridge and three derivatives with a 1,2,3-triazole differing from each other by the presence of sulfur or oxygen in their staples were prepared. The strongest binding to IR was exhibited by the peptide with a disulfide bridge. All other derivatives only weakly bound to IR, and a relationship between increasing bridge length and lower binding affinity can be inferred. Despite their nanomolar affinities, none of the prepared peptide mimetics was able to activate the insulin receptor even at high concentrations, but all mimetics were able to inhibit insulin-induced receptor activation. However, the receptor remained approximately 30% active even at the highest concentration of the agents; thus, the agents behave as partial antagonists. An interesting observation is that these mimetic peptides do not antagonize insulin action in proportion to their binding affinities. The compounds characterized in this study show that it is possible to modulate the functional properties of insulin receptor peptide ligands using disulfide mimetics.     

Estimation of total hemolymph volume in the horseshoe crab Limulus polyphemus

Biomedical companies extract blood from the horseshoe crab, Limulus polyphemus, for the production of Limulus Amebocyte Lysate, used worldwide for detecting endotoxins in injectable solutions and medical devices. Despite the extensive use of horseshoe crabs by the biomedical industry, total hemolymph volume for this species is not known. The hemolymph volume of 60 adult horseshoe crabs was estimated using an inulin dilution technique. Blood volume of the horseshoe crab represented as a percentage of wet body weight was 25?±?2.2% for males and 25?±?5.1% (mean?±?SD) for females. Relationships between hemolymph volume and weight (p?=?0.0026, r ²?=?0.8762), hemolymph volume and prosomal width (p?<?0.0001), and hemolymph volume and inter-ocular width (p?<?0.0001) were observed. No significant differences were observed between males and females. The relationship of animal size and hemolymph volume can be used to predict how much blood can be drawn from horseshoe crabs used by the biomedical industry, and can be of further use in future bleeding mortality studies.