Solution- and solid-phase synthesis and anti-HIV activity of maslinic acid derivatives containing amino acids and peptides

Maslinic acid (1) has been coupled at C-28 with several α- and ω-amino acids by using solution- and solid-phase synthetic procedures. Twelve derivatives (2–13) with a single amino acid residue were prepared in solution phase, whereas a dipeptide (14), a tripeptide (15), and a series of conjugate dipeptides (16–24) were synthesized in solid phase. The anti-HIV activity of these compounds was assessed on MT-2 cells infected with viral clones carrying the luciferase gene as a reporter. While in maslinic acid (1) were present both cytotoxic and antiviral activities, only the derivatives 13 and 24 showed anti-HIV-1 activity and therefore represent a novel class of anti-HIV-1 compounds.     

Joint analysis for heading date QTL in small interconnected barley populations

The purpose of the present work is to validate the effect of the main QTL determining heading date in a set of 281 doubled haploid lines of barley, derived from 17 small interconnected populations, whose parents are cultivars commonly used in the Spanish barley breeding program. We used 72 molecular markers distributed across the seven chromosomes, particularly in regions known to contain flowering time genes or QTL. A combined linkage map over the 17 populations was constructed. The lines were evaluated in four field trials: two autumn sowings and two winter sowings, and in two treatments at a greenhouse trial, under controlled conditions of photoperiod and temperature. We have found that it is possible to carry out QTL detection in a complex germplasm set, representative of the materials used in an active breeding programme. In most cases two alleles per QTL were detected, though polymorphism of flanking markers was notably higher. The results revealed that there is a set of QTL that accounts for an important percentage of the phenotypic variation, suitable for marker assisted selection. Also, the role of the regions carrying the photoperiod response genes Ppd-H1 and Ppd-H2, the vernalization response genes Vrn-H1 and Vrn-H2, and the earliness per se locus Eam6, of which allele-specific or closely linked markers were available, was confirmed. These results support the use of this kind of approach for the validation of QTL found in single cross population studies, or to survey allelic diversity in plant breeding sets of materials. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evaluation of abdominal wall strength after TRAM flap surgery

Evaluation of abdominal wall function after transverse rectus abdominis musculocutaneous (TRAM) flap surgery has been mostly subjective. The purpose of this study was to measure abdominal wall strength objectively and to compare the results with the patient's performance of daily activities. Abdominal wall strength was objectively measured with the B200 IsoStation machine preoperatively and 1 year after TRAM flap breast reconstruction. These data were compared with the results of a questionnaire evaluating the patient's performance of daily activities. The results of this testing in 21 patients demonstrated the following: (1) a decrease in abdominal wall strength after bilateral pedicled TRAM flap surgery, which was significant in trunk flexion (34.2 +/- 16.9 ft-lbs to 20.6 +/- 15.2 ft-lbs); (2) compensation by other truncal musculature, with an increase in the strength of trunk rotation (18.8 +/- 13.5 ft-lbs to 28.6 +/- 17.7 ft-lbs) seen after unilateral pedicled TRAM flap surgery; (3) minimal interference with the patient's daily activities; and (4) no effect of mesh on strength. A relationship was demonstrated between the degree of loss of strength in trunk flexion and the patient's difficulty in performing certain activities. The patients who had the greatest loss in trunk flexion following the use of both pedicles also had the most difficulty in performing some daily activities. The patients were satisfied with their reconstructive procedure, with an average score of 8.3 (on a scale of 1 to 10), and reported an improvement in the appearance of their abdomen, with an average increase of 5.1 to 6.8 (on a scale of 1 to 10).     

Differential expression and cellular localization of ERKs during organogenic nodule formation from internodes of Humulus lupulus var. Nugget

The expression and subcellular localization of extracellular signal-regulated kinase 1 or 2 (ERK1/2) homologues (HLERK1/2) during the process of organogenic nodule formation in Humulus lupulus var. Nugget was studied using antibodies specific for ERK1 and ERK2, and for phosphorylated mitogen-activated protein kinases (MAPKs). The increase in HLERK levels, detected by Western blotting 12 hours after wounding suggests their involvement in response to the wounding treatment applied for morphogenesis induction. In dividing cambial cells, occurring in between 4 and 7 days after morphogenesis induction, as well as in dividing prenodular cells (15 days after induction) HLERK1 and/or 2 were localized in the nucleus. However, as soon as nodular cells start proliferating to form shoot meristems, HLERK1 and 2 were detected in the cytoplasm and not in the nucleus. The data reported account for a differential expression and activation of HLERK1 and HLERK2 throughout the process of nodule formation and plantlet regeneration. HLERK1 appears to be expressed in the stages of nodule formation and plantlet regeneration, playing a possible role in controlling cell proliferation and differentiation. HLERK2 may be induced as a response to reactive oxygen species (ROS) generated by wounding of internodes as its expression is reduced in liquid medium with less oxygen availability compared to solid medium. However, addition of a ROS inhibitor to the liquid medium does not result in a further decrease in the HLERK2 level.     

Floral zygomorphy, the recurring evolution of a successful trait

The flowers of the primitive angiosperm plants were radially symmetrical (actinomorphic). Flowers with bilateral symmetry (zygomorphic) evolved in several clades independently as an adaptation to specialized methods of pollination and played an important role in the diversification of flowering plants. In the model species Antirrhinum majus (snapdragon), the related genes CYCLOIDEA (CYC) and DICHOTOMA (DICH) are key in the development of this trait. This raises the question of whether they played a role in the evolution of floral bilateral symmetry. To address this, the evolution of CYC in relation to the evolution of zygomorphy is being investigated. Phylogenetic and functional analyses of CYC-like genes are being carried out in groups either closely related to Antirhinum or in families where zygomorphy evolved as an independent event. In addition, the origin of zygomorphy is being studied by comparing the function of CYC-like genes in species with zygomorphic flowers with their function in species with radially symmetrical flowers.     

Novel epicatechin derivatives with antioxidant activity modulate interleukin-1beta release in lipopolysaccharide-stimulated human blood

We examine the potential antioxidant activity and the immune function of new epicatechin conjugates obtained by depolymerization of grape polymeric flavanols in the presence of cysteamine or cysteine. When incubated with an erythrocyte suspension, flavanols protected the erythrocyte membrane from hemolysis induced by 2,2'-azo-bis(2-amidinopropane)dihydrochloride (AAPH), an azo free radical initiator. The inhibitory effect was concentration-dependent and the IC50 was 119.8 microM for epicatechin, and 74.9 and 89.4 microM for the cysteine and cysteamine derivatives, respectively. These compounds were tested for their antioxidant activity and their capacity to modulate interleukin-1beta (IL-1beta), which is currently considered to be the major cytokine factor influencing the acute phase of the inflammatory response. At concentrations up to 20 microM, epicatechin and its derivatives inhibited the production of IL-1beta in whole blood incubated in the presence of E. coli lipopolysaccharide (LPS), in a concentration-dependent manner. The most active compound was the cysteamine derivative.     

Hyperammonemia Impairs NMDA Receptor-Dependent Long-Term Potentiation in the CA1 of Rat Hippocampus In Vitro

Hyperammonemia is considered the main factor responsible for the neurological and cognitive alterations found in hepatic encephalopathy and in patients with congenital deficiencies of the urea cycle enzymes. The underlying mechanisms remain unclear. Chronic moderate hyperammonemia reduces nitric oxide-induced activation of soluble guanylate cyclase and glutamate-induced formation of cGMP. NMDA receptor-associated transduction pathways, including activation of soluble guanylate cyclase, are involved in the induction of long-term potentiation (LTP), a phenomenon that is considered to be the molecular basis for some forms of memory and learning. Using an animal model we show that chronic hyperammonemia significantly reduces the degree of long-term potentiation induced in the CA1 of hippocampus slices (200% increase in control and 50% increase in slices of hyperammonemic animals). Also, addition of 1 mM ammonia impaired the maintenance of non-decremental LTP. The LTP impairment could be involved in the intellectual impairment present in chronic hepatocerebral disorders associated with hyperammonemia.     

Phosphorylated, but not native, tau protein assembles following reaction with the lipid peroxidation product, 4-hydroxy-2-nonenal

A correlation between hyperphosphorylation of tau protein and its aberrant assembly into paired helical filaments has lead to suggestions that phosphorylation controls assembly, but lacked a mechanistic basic. In this work, we have found that phosphorylated, but not native, tau protein is able to form polymers after the reaction with 4-hydroxy-2-nonenal, a highly toxic product of lipid peroxidation. Phosphorylation of tau by both proline or non-proline directed kinases, was able to assemble it into polymers.     

Role of the PI3K regulatory subunit in the control of actin organization and cell migration

Cell migration represents an important cellular response that utilizes cytoskeletal reorganization as its driving force. Here, we describe a new signaling cascade linking PDGF receptor stimulation to actin rearrangements and cell migration. We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes. Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K. Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen. These observations show the essential role of the PI3K regulatory subunit p85alpha in controlling PDGF receptor-induced cytoskeletal changes and cell migration, illustrating a novel signaling pathway that links receptor stimulation at the cell membrane with actin dynamics.