Patterns of energy content in plants from the venezuelan paramos

Summary Determinations of energy and ash content were made on the organs of some common plant species from an elevational gradient in the Venezuelan páramos. The results indicate differences in energy content among the life forms sampled. Giant rosette plants show the highest values in the roots while woody plants have the highest energy content in the leaves. The reproductive organs show a higher energy content than the vegetative organs. There is a tendency to increase energy content as elevation and environmental stress increase. The adaptive significance of these patterns is discussed. The high average energy value for páramo plants, 20.18 KJ/g ash free dry weight, is similar to values reported for alpine tundra plants and conifer forests.     

Regulation of Hsp70 function by HspBP1: structural analysis reveals an alternate mechanism for Hsp70 nucleotide exchange

HspBP1 belongs to a family of eukaryotic proteins recently identified as nucleotide exchange factors for Hsp70. We show that the S. cerevisiae ortholog of HspBP1, Fes1p, is required for efficient protein folding in the cytosol at 37 degrees C. The crystal structure of HspBP1, alone and complexed with part of the Hsp70 ATPase domain, reveals a mechanism for its function distinct from that of BAG-1 or GrpE, previously characterized nucleotide exchange factors of Hsp70. HspBP1 has a curved, all alpha-helical fold containing four armadillo-like repeats unlike the other nucleotide exchange factors. The concave face of HspBP1 embraces lobe II of the ATPase domain, and a steric conflict displaces lobe I, reducing the affinity for nucleotide. In contrast, BAG-1 and GrpE trigger a conserved conformational change in lobe II of the ATPase domain. Thus, nucleotide exchange on eukaryotic Hsp70 occurs through two distinct mechanisms.     

Optimization of cultivation conditions in spin tubes for Chinese hamster ovary cells producing erythropoietin and the comparison of glycosylation patterns in different cultivation vessels

This article describes the optimization of cultivation factor settings, that is the shaking rate and working volume in 50 mL spin tubes for a Chinese hamster ovary cell line expressing recombinant human α‐erythropoietin, using a response D‐optimal surface method. The main objectives of the research were, firstly, to determine a setting in which the product titer and product quality attributes in spin tubes are equivalent to those in 250 mL shake flasks in a seven day batch and, secondly, to find a setting in which the product titer is maximal. The model for product titer prediction as a function of shaking rate and working volume in the defined design space was successfully applied to the optimization of cultivation conditions in spin tubes for the tested cell line. Subsequently, validation experiments were carried out simultaneously in spin tubes, shake flasks and bench scale bioreactors to compare cell culture performance parameters such as growth, productivity and product quality attributes in the form of isoform profiles and glycan antennarity structures. The results of the experiments showed that similar cell culture performance and product quality could be achieved in spin tubes when compared to shake flasks. Additionally, bioreactor titers could be reproduced in spin tubes at high shaking rates and low working volumes, but with differing product quality. Cultivation at lower shaking rates in spin tubes and shake flasks produced a glycoprotein with a product quality slightly comparable to that from bioreactors, but with titers being only two thirds. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Genetic split between coastal and continental populations of gypsy moth separated by Dinaric Alps

The gypsy moth, a polyphagous herbivore species, infests mainly deciduous trees in the northern hemisphere, being invasive in North America. In Croatia, gypsy moth is infesting both continental and coastal forests, with the Dinaric Alps posing a physical migratory barrier between two regions. During outbreaks, caterpillars cause severe damages in both regions, though with different outbreak dynamics, which suggests genetic differences between populations. Representative populations from these two regions were screened by sequencing a region of the mitochondrial COI gene. Ninety‐nine sequences resulted in seventeen haplotypes, and analyses revealed a significant genetic differentiation between coastal and continental populations, quite likely attributed to geographic isolation and post‐glacial history. This differentiation arises from significantly higher genetic variability in Mediterranean population, indicating their higher adaptability, an intriguing fact in case of possible northward range shift of gypsy moth.     

Hemiarthroplasty is an effective surgical method to manage unstable trochanteric fractures in elderly people

Trochanteric femoral fractures are a major problem in the elderly because of higher bone fragility due to osteoporosis. Numerous chronic illnesses, which usually affect the elderly, aggravate and complicate their surgical treatment. Trochanteric femoral fractures results in high morbidity and mortality in elderly patients. The aim of our study is to evaluate the effectiveness of hemiarthroplasty in the treatment of unstable trochanteric femoral fractures in elderly patients. Between 2000 and 2005, 50 patients with unstable trochanteric femoral fractures (41 women) aged 75 to 92 years (mean 86 years) underwent cemented hemiarthroplasty. The surgical procedure was performed within first 48 hours after the fracture (out of which 14 in the first 12 hours, 27 in the first 24 hours and 9 in the first 48 hours), with minimal blood loss. Hemiarthroplasty was indicated in patients where stability was important to allow early mobilization. In forty patients (80%) early ambulation with full weight bearing was achieved during the short period of hospitalization (9-14 days). Given that the affected population is predominantly the elderly, who are less mobile and demanding and thus put less strain on the endoprosthesis, we believe that this kind of treatment is the treatment of choice for unstable trochanteric femoral fractures in these patients. This assumption is corroborated by the fact that we did not have any endoprosthesis luxation, apparent acetabular protrusion or instability during the mean follow up period of 15 months (range 12-18 months).     

Formation of adhesions at surgical meshes in a rat experimental model

Abdominal wall hernias are surgical problem that are easily solved with laparoscopic surgery. The determining factor for the success of the operation is the right choice and use of surgical mesh as the support material. The most common complication of surgical mesh placement is the formation of adhesions. Aim of this paper is to determine whether there is a statistic difference in formation of adhesions between different surgical meshes in lab environment. Wistar rats were used as the experimental model. After the anaesthesia a 1x1 cm defect of the abdominal wall was made, but the skin was left intact. The mesh was placed directly on the internal organs. The experiment considered four different mesh types. After set time periods of one, two or four weeks the animals were sacrificed and the amount of formed adhesions were evaluated based on the modified Diamond scale. Immediately after the first week we found a statistically significant difference in the adhesion occurrence rate between compared materials. The smallest amount of adhesions was caused by polypropylen + polydoksanon mesh, and the most by polypropilen mesh. Polypropylen + polyglactin mesh showed significant reduction of adhesion formation between the tested weeks. We can conclude that polypropylen + polydoxanon meshes are superior for ventral hernia operation, because those defects are in close contact with the internal organs and it is very important to have the smallest amount of adhesions.     

Novel series of pyrrolotriazine analogs as highly potent pan-Aurora kinase inhibitors

The synthesis and SAR for a novel series of pyrrolotriazines as pan-Aurora kinase inhibitors are described. Optimization of the cyclopropane carboxamide terminus of lead compound 1 resulted in analogs with high cellular activity and improved rat PK profiles. Notably, compound 17l demonstrated tumor growth inhibition in a mouse xenograft model.     

Genetic evidence that DNA methyltransferase DRM2 has a direct catalytic role in RNA-directed DNA methylation in Arabidopsis thaliana

RNA-directed DNA methylation (RdDM) is a small RNA-mediated epigenetic modification in plants. We report here the identification of DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) in a forward screen for mutants defective in RdDM in Arabidopsis thaliana. The finding of a mutation in the presumptive active site argues in favor of direct catalytic activity for DRM2.