Exploring the Biological Properties of Zn(II) thiosemicarbazone Helicates.

The design of artificial helicoidal molecules derived from metal ions with biological properties is one of the objectives within metallosupramolecular chemistry. Herein, we report three zinc helicates derived from a family of thiosemicarbazone ligands with different terminal groups, Zn(L)∙2HO , Zn(L)∙2HO and Zn(L), obtained by an electrochemical methodology. These helicates have been fully characterized by different techniques, including X-ray diffraction.

Could inhibition of metalloproteinases be used to block the process of metastasis?

Metastasis is a multisequential process that allows tumor cells to migrate to tissues distant from the primary tumor. Only a small number of cells escape from the primary tumor; however, the metastases generated are responsible for more than 90% of cancer deaths. Many metastatic processes initially require the total or partial start-up of a program for the transformation of tumor epithelial cells into mesenchymal cells (EMT).

Spectroscopic Characterization of Mitochondrial G-Quadruplexes.

Guanine quadruplexes (G4s) are highly polymorphic four-stranded structures formed within guanine-rich DNA and RNA sequences that play a crucial role in biological processes. The recent discovery of the first G4 structures within mitochondrial DNA has led to a small revolution in the field. In particular, the G-rich conserved sequence block II (CSB II) can form different types of G4s that are thought to play a crucial role in replication.

Inhibition of glutathione reductase uncovers the activation of NADPH-inhibited glucose-6-phosphate dehydrogenase.

Eggleston and Krebs pointed to a paradox in glucose-6-phosphate dehydrogenase (G6PD) regulating process that has not yet been solved, and which originated the term "fine regulation" of G6PD and, therefore, of oxidative phase of pentose phosphate pathway (OPPP). The paradox is that, in basal-like conditions, the activity of G6PD evaluated "in vitro" is very low or nearly null because of the potent inhibiting effect exerted by NADPH, a coenzyme whose concentration in the cell is much higher than that of the substrate NADP . However, "in vivo," flow through OPPP occurs in basal conditions.

Structural, morphometric and immunohistochemical study of the rabbit accessory olfactory bulb.

The accessory olfactory bulb (AOB) is the first neural integrative centre of the vomeronasal system (VNS), which is associated primarily with the detection of semiochemicals. Although the rabbit is used as a model for the study of chemocommunication, these studies are hampered by the lack of knowledge regarding the topography, lamination, and neurochemical properties of the rabbit AOB. To fill this gap, we have employed histological stainings: lectin labelling with Ulex europaeus (UEA-I), Bandeiraea simplicifolia (BSI-B4), and Lycopersicon esculentum (LEA) agglutinins, and a range of immunohistochemical markers.

Sensitivity of the kinase activity of human vaccinia-related kinase proteins to toxic metals.

The human vaccinia-related kinase (VRK) proteins VRK1 and VRK2 regulate different processes, such as the cell cycle, DNA damage response, and signaling by mitogen-activated protein kinases in response to growth factors or cellular stress. Alterations in expression levels of these Ser-Thr kinases are associated with cancer and neurodegenerative diseases. These functions suggest that they might also be targets of toxic metals, and thus contribute to the pathogenic effects associated with metal intoxication.

Differential inhibitor sensitivity between human kinases VRK1 and VRK2.

Human vaccinia-related kinases (VRK1 and VRK2) are atypical active Ser-Thr kinases implicated in control of cell cycle entry, apoptosis and autophagy, and affect signalling by mitogen activated protein kinases (MAPK). The specific structural differences in VRK catalytic sites make them suitable candidates for development of specific inhibitors. In this work we have determined the sensitivity of VRK1 and VRK2 to kinase inhibitors, currently used in biological assays or in preclinical studies, in order to discriminate between the two proteins as well as with respect to the vaccinia virus B1R kinase.

After the Prestige oil spill modifications in NO production and other parameters related to the immune response were detected in hemocytes of Mytilus galloprovincialis.

In marine mollusks, many physiologic functions are regulated seasonally depending on such factors as the reproductive cycle or the presence of food. The synthesis of nitric oxide by hemocytes of Mytilus galloprovincialis is among the multiple physiologic actions in the immune response, and it is also affected by season. The maximal basal production of NO by hemocytes of M.

Implication of PKC in the seasonal variation of the immune response of the hemocytes of Mytilus galloprovincialis Lmk. and its role in interleukin-2-induced nitric oxide synthesis.

The hemocytes are the cells responsible for the immune response in marine mollusks. The role of NO in processes related to the activation of the hemocytes has turned out evident over the late years. In the case of the mussel Mytilus galloprovincialis Lmk.

In hemocytes from Mytilus galloprovincialis Lmk., treatment with corticotropin or growth factors conditions catecholamine release.

The cells in charge of the innate immune response in the sea mussel Mytilus galloprovincialis Lmk. are the hemocytes, which have the capacity to release catecholamines when subjected to stressing conditions. Hemocytes were kept in culture before stimulation.

Nitric oxide production by haemocytes from Mytilus galloprovincialis shows seasonal variations.

Nitric oxide (NO) has been identified as an important physiological modulator, with evidence of its role as a signalling molecule throughout the whole phylogenetic scale. In marine molluscs, it intervenes in processes related to the immune function of haemocytes. The presented results indicate that basal NO production by haemocytes of Mytilus galloprovincialis shows seasonal variations, with summer values statistically higher than those of winter.

The vaccinia virus B1R kinase induces p53 downregulation by an Mdm2-dependent mechanism.

Poxvirus infection has a strong effect on cellular functions. To understand viral pathogenesis, it is necessary to know how viral proteins interact with host proteins. The B1R kinase is an early viral gene required for vaccinia virus DNA synthesis and replication, but no cellular substrate is known for this viral kinase.

c-Jun phosphorylation by the human vaccinia-related kinase 1 (VRK1) and its cooperation with the N-terminal kinase of c-Jun (JNK).

The VRK1 kinase is a novel Ser-Thr kinase in the human kinome that diverged from the casein kinase 1 branch. These kinases phosphorylate transcription factors related to stress responses, such as p53. In this report we have studied the phosphorylation of the transcription factor c-Jun in its N-terminal region.

Implication of PKA and PKC in the activation of the haemocytes of Mytilus galloprovincialis Lmk by LPS and IL-2.

LPS and IL-2 play an essential role in the generation of the immune response in diverse eukaryotic species, as they provoke the activation of several pathways of signal transduction in macrophages. Among the kinases related to these pathways, PKA and the PKCs are some of the most important. In the haemolymph of the marine mussel Mytilus galloprovincialis Lmk, the cells responsible for the defence reactions are the haemocytes.

In vitro effects of LPS, IL-2, PDGF and CRF on haemocytes of Mytilus galloprovincialis Lmk.

The cells in charge of the innate immune response in the marine mussel Mytilus galloprovincialis Lmk. are the haemocytes. These cells respond in different ways to agents such as lipopolysaccharide (LPS), interleukin-2 (IL-2), platelet-derived growth factor (PDGF) and corticotropin releasing factor (CRF).

Nitric oxide release by hemocytes of the mussel Mytilus galloprovincialis Lmk was provoked by interleukin-2 but not by lipopolysaccharide.

As other marine and land mollusks, mussels have special cells in charge of the immune function called hemocytes. The activation of these cells leads to a series of events that end up in phagocytosis and in secretion of digestive enzymes that eliminate the pathogen. The production of nitric oxide is among the early activation processes.

Phorbol esters induce translocation of the nPKC p105 to membrane in mussel hemocytes.

Previous works revealed the presence of the nPKC enzyme p105 in hemocytes of M. galloprovincialis Lmk. Specific mussel antibodies were obtained from mouse and used in confocal microscopy and Western blotting.

Regulatory properties of p105: a novel PKC isoenzyme in mantle tissue from marine mussels.

Previous results suggested operative similarities between Apl II from nervous cells of Aplysia californica, epsilonPKC from brain of vertebrates, and p105 from mantle tissue of Mytilus galloprovincialis Lmk., all of them belonging to the nPKC family. The optimal substrate for Apl II and p105 from mussel is protamine sulfate.

Purification of a lipid-activated and Ca2+-independent protein kinase from the mantle tissue of Mytilus galloprovincialis Lmk.

A phospholipid-sensitive Ca2+-independent protein kinase (p105) was purified to homogeneity from mantle tissue of the mussel Mytilus galloprovincialis Lmk., employing consecutively DE-52 cellulose, Sephacryl S-200 and Biogel HTP chromatographies. The purified enzyme appeared as a single band on 10% SDS-PAGE, and had a molecular weight of 105 kDa.

Kinetic properties of p53 phosphorylation by the human vaccinia-related kinase 1.

The vaccinia-related kinase 1 (VRK1) protein is a nuclear Ser-Thr kinase that phosphorylates p53 in Thr18. We have determined the enzyme properties regarding its different substrates. VRK1 has a high affinity for ATP (K(m) 50 microM) and is thus saturated by the intracellular concentration of ATP in vivo.

Transient activation of the c-Jun N-terminal kinase (JNK) activity by ligation of the tetraspan CD53 antigen in different cell types.

The CD53 antigen is a member of the tetraspanin membrane protein family that is expressed in the lymphoid-myeloid lineage. We have studied the implication of CD53 antigen in signal transduction by determining the effect of its ligation on the c-Jun N-terminal kinase (JNK) in different cell types. Ligation of the rat or human CD53 antigen induces a three- to fourfold transient activation of JNK activity that peaks at 3-5 min.