Hypothyroidism provides resistance to kidney mitochondria against the injury induced by renal ischemia-reperfusion

Massive Ca(2+) accumulation in mitochondria, plus the stimulating effect of an inducing agent, i.e., oxidative stress, induces the so-called permeability transition, which is characterized by the opening of a nonspecific pore. This work was aimed at studying the influence of thyroid hormone on the opening of such a nonspecific pore in kidney mitochondria, as induced by an oxidative stress. To meet this objective, membrane permeability transition was examined in mitochondria isolated from kidney of euthyroid and hypothyroid rats, after a period of ischemia/reperfusion. It was found that mitochondria from hypothyroid rats were able to retain accumulated Ca(2+) to sustain a transmembrane potential after Ca(2+) addition, as well as to maintain matrix NAD(+) and membrane cytochrome c content. The protective effect of hypothyroidism was clearly opposed to that occurring in ischemic reperfused mitochondria from euthyroid rats. Our findings demonstrate that these mitochondria were unable to preserve selective membrane permeability, except when cyclosporin A was added. It is proposed that the protection is conferred by the low content of cardiolipin found in the inner membrane. This phospholipid is required to switch adenine nucleotide translocase from specific carrier to a non-specific pore.     

Comparative characterisation of thiamin diphosphate-dependent decarboxylases

Several 2-keto acid decarboxylases catalyse an acyloin condensation-like carboligase reaction beside their physiological decarboxylase activity. Although many data concerning stability and catalytic potential of these enzymes are available, a standard evaluation under similar reaction conditions is lacking. In this comprehensive survey we assemble already published data combined with new studies of three bacterial pyruvate decarboxylases, yeast pyruvate decarboxylase, benzoylformate decarboxylase from Pseudomonas putida (BFD) and the branched-chain 2-keto acid decarboxylase from Lactococcus lactis (KdcA). The obtained results proof that the optima for activity and stability are rather similar if comparable reaction conditions are used. Although the substrate ranges of the decarboxylase reaction of the various pyruvate decarboxylases are similar as well, they differ remarkably from those of BFD and KdcA. We further show that the range of acceptable donor aldehydes for the carboligase reaction of a respective enzyme can be reliably predicted from the substrate range of decarboxylase reaction.     

Development and validation of a weight-bearing finite element model for total knee replacement

Total knee arthroplasty (TKA) is a successful procedure for osteoarthritis. However, some patients (19%) do have pain after surgery. A finite element model was developed based on boundary conditions of a knee rig. A 3D-model of an anatomical full leg was generated from magnetic resonance image data and a total knee prosthesis was implanted without patella resurfacing. In the finite element model, a restarting procedure was programmed in order to hold the ground reaction force constant with an adapted quadriceps muscle force during a squat from 20° to 105° of flexion. Knee rig experimental data were used to validate the numerical model in the patellofemoral and femorotibial joint. Furthermore, sensitivity analyses of Young’s modulus of the patella cartilage, posterior cruciate ligament (PCL) stiffness, and patella tendon origin were performed. Pearson’s correlations for retropatellar contact area, pressure, patella flexion, and femorotibial ap-movement were near to 1. Lowest root mean square error for retropatellar pressure, patella flexion, and femorotibial ap-movement were found for the baseline model setup with Young’s modulus of 5 MPa for patella cartilage, a downscaled PCL stiffness of 25% compared to the literature given value and an anatomical origin of the patella tendon. The results of the conducted finite element model are comparable with the experimental results. Therefore, the finite element model developed in this study can be used for further clinical investigations and will help to better understand the clinical aspects after TKA with an unresurfaced patella.     

A novel phosphatase family, structurally related to dual-specificity phosphatases, that displays unique amino acid sequence and substrate specificity

Members of the superfamily of protein tyrosine phosphatases (PTPs) share the presence of an evolutionarily conserved PTP catalytic domain. Among them, the dual-specificity phosphatases (DSPs) constitute a diverse group of enzymes in terms of substrate specificity, including nonprotein substrates. In recent years, an increasing number of novel DSPs, whose functions and biological substrates are not well defined, have been discovered in a variety of organisms. In this study, we define the structural and functional properties of evolutionarily related atypical DSPs from different phyla. Sets of conserved motifs were defined that (i) uniquely segregated mammalian atypical DSPs from closely related enzymes and (ii) exclusively characterised a novel family of atypical DSPs present in plants, fungi, and kinetoplastids [plant and fungi atypical (PFA)-DSPs]; despite having different sequence “fingerprints,” the PTP tertiary structure of PFA-DSPs is conserved. Analysis of the catalytic properties of PFA-DSPs suggests the existence of a unique substrate specificity for these enzymes. Our findings predict characteristic functional motifs for the diverse members of the DSP families of PTPs and provide insights into the functional properties of DSPs of unknown function.     

Prediction of enzyme function based on 3D templates of evolutionarily important amino acids

Background  

Structural genomics projects such as the Protein Structure Initiative (PSI) yield many new structures, but often these have no known molecular functions. One approach to recover this information is to use 3D templates – structure-function motifs that consist of a few functionally critical amino acids and may suggest functional similarity when geometrically matched to other structures. Since experimentally determined functional sites are not common enough to define 3D templates on a large scale, this work tests a computational strategy to select relevant residues for 3D templates.     

Reproductive strategies in female polar and deep-sea bobtail squid genera <Emphasis Type="Italic">Rossia</Emphasis> and <Emphasis Type="Italic">Neorossia</Emphasis> (Cephalopoda: Sepiolidae)

Female reproductive features have been investigated in five polar and deep-sea bobtail squid genera Rossia and Neorossia (R. macrosoma, R. moelleri, R. pacifica, N.c. caroli and N.c. jeannae). These species are characterized by asynchronous ovary maturation, very large eggs (>10% ML), fecundity of several hundred oocytes, very high reproductive output, and continuous spawning with low batch fecundity. This adaptive complex of reproductive traits evolved in these small animals as an optimum strategy for polar and deep-water habitats.     

7-Arylpiperazinylalkyl and 7-tetrahydroisoquinolinylalkyl derivatives of 8-alkoxy-purine-2,6-dione and some of their purine-2,6,8-trione analogs as 5-HT(1A), 5-HT(2A), and 5-HT(7) serotonin receptor ligands

On the basis of our earlier studies with the serotonin receptor ligands in the group of 1,3-dimethyl-3,7-dihydropurine-2,6-dione derivatives, a series of new arylpiperazinylalkyl and tetrahydroisoquinolinylalkyl analogs of 8-alkoxy-1,3-dimethyl-3,7-dihydropurine-2,6-dione (10-25) and 1,3-dimethyl-7,9-dihydro-3H-purine-2,6,8-trione (26-30) were synthesized and their 5-HT(1A), 5-HT(2A), and 5-HT(7) receptor affinities were determined. The new compounds 17, 18, 20, and 21 were found to be highly active 5-HT(1A) receptor ligands (K(i)=11-19nM) with diversified affinity for 5-HT(2A) receptors (K(i)=15-253nM). Compounds 12, 13, 15, and 19 were moderately potent 5-HT(2A) ligands (K(i)=23-57nM), whereas 17, 18, 24, and 25 showed distinct affinity for 5-HT(7) receptors (K(i)=51-83nM). Purine-2,6,8-triones showed weak affinities for 5-HT(1A) and 5-HT(7) receptors; among them, 27 and 29 were classified as 5-HT(2A) receptor ligands. The selected compounds 17 and 21 were pharmacologically evaluated to determine their functional activities at pre-(hypothermia in mice) and post-(lower lip retraction in rats) synaptic 5-HT(1A) receptors. Compound 17 showed features of a potential agonist of pre- and post-synaptic 5-HT(1A) receptors, whereas 21 was classified as a potential, weak partial agonist of postsynaptic sites. Last of all, the most interesting compound 17 tested in behavioral models showed potential anxiolytic and antidepressant activities.     

Cytokinins contribute to realization of nitric oxide growth-stimulating and protective effects on wheat plants

We investigated effects of sodium nitroprusside (SNP), the donor of nitric oxide (NO), on the growth and hormonal system of wheat plants (Triticum aestivum L.) in normal conditions and after salt stress (2% NaCl). During germination of seeds treated with SNP (50–500 μM), we obtained the SNP concentration (200 μM) optimal for stimulation of seedling growth estimated by increase in seed germination capacity and seedlings' linear sizes and their fresh and dry biomass. A comparative analysis of SNP (200 μM) effects, after seed germination in the medium with SNP or pretreatment of 3-day-old seedlings, showed SNP ability to increase the wheat plant resistance to subsequent effects of sodium chloride salinity at both treatment methods. Protective SNP effects appeared in the reduction of stress inhibitory action on seedling growth rates and significant reduction in the level of lipid peroxidation and exosmosis of electrolytes. An important contribution to realization of the growth-stimulating and protective effects of NO is associated with its ability to influence the state of the hormonal system of wheat plants due to an increase in the concentration of hormones of a cytokinin nature under normal conditions and the prevention of a decrease in their level under stress.     

Personalized Oncogenomics: Clinical Experience with Malignant Peritoneal Mesothelioma Using Whole Genome Sequencing

Peritoneal mesothelioma is a rare and sometimes lethal malignancy that presents a clinical challenge for both diagnosis and management. Recent studies have led to a better understanding of the molecular biology of peritoneal mesothelioma. Translation of the emerging data into better treatments and outcome is needed. From two patients with peritoneal mesothelioma, we derived whole genome sequences, RNA expression profiles, and targeted deep sequencing data. Molecular data were made available for translation into a clinical treatment plan. Treatment responses and outcomes were later examined in the context of molecular findings. Molecular studies presented here provide the first reported whole genome sequences of peritoneal mesothelioma. Mutations in known mesothelioma-related genes NF2, CDKN2A, LATS2, amongst others, were identified. Activation of MET-related signaling pathways was demonstrated in both cases. A hypermutated phenotype was observed in one case (434 vs. 18 single nucleotide variants) and was associated with a favourable outcome despite sarcomatoid histology and multifocal disease. This study represents the first report of whole genome analyses of peritoneal mesothelioma, a key step in the understanding and treatment of this disease.