Novel antifungal agents: Triazolopyridines as inhibitors of β-1,6-glucan synthesis

Preparations and in vitro antifungal activities of triazolopyridines, imidazopyridines, and a pyrazolopyridine were reported. Among those scaffolds, triazolopyridine was found to be the specific inhibitor of the synthesis of β-1,6-glucan, an essential component of the fungal cell wall, and to show potent antifungal activities against several Candida species.     

Identification of several chloroplast DNA genes which code for the large subunit of Nicotiana Fraction I proteins

Summary Electrofocusing of carboxymethylated, crystalline Fraction I proteins in polyacrylamide gels containing 8 M urea resolves the large subunit into three major peptides and the small subunit into one or more peptides. Electrofocusing of proteins isolated from leaves of the reciprocal, F₁, hybrids: N. glutinosa x N. tabacum, N. glauca x N. tabacum, N. glauca x N. langsdorfii and the parental species confirms that coding information for the large subunit is inherited only by the maternal line whereas both parents contribute coding information for the small subunit. The analysis shows that one or more of the three peptides of the large subunit of Fraction I proteins from different Nicotiana species differ in isoelectric point and therefore serve as phenotypic markers for chloroplast DNA genes.     

Visualization of microtubule-mediated transport of influenza viral progeny ribonucleoprotein

We developed a unique monoclonal antibody, mAb61A5, using the nucleoprotein (NP) of influenza virus A/Puerto Rico/8/34 (PR8) strain. Truncation and alanine substitution experiments showed that mAb61A5 recognized the NP fragment with residues 17 to 123 in which a conformational epitope formed by the beta1 sheet and the linker region between the alpha1 and alpha2 helices. Variations in the epitope or nearby can partly account for the poor mAb61A5 reactivity with the NP of A/Aichi/2/68 or A/duck/Pennsylvania/10128/84 strains. Interestingly, immunoprecipitation analysis revealed that mAb61A5 preferentially interacted with viral ribonucleoprotein complexes, composed of RNA polymerase, negative/positive sense RNA and NP, rather than exogenously added NP. Immunofluorescence microscopy using mAb61A5 showed a punctate staining in the cytoplasm during the late phase of infection. The punctate NPs accumulated at the microtubule organizing center and co-localized with microtubules. The treatment with leptomycin B to block a CRM1-dependent nuclear export failed to produce the punctate NP. The treatment with nocodazole, a microtubule-depolymerizing agent, showed random distribution of the punctate NP in the cytoplasm. These results suggest that microtubule networks, although were not required for the formation of punctate structures, were responsible for the polarized distribution of the punctate NP antigens, most likely viral progeny ribonucleoprotein complexes.     

A Soluble Form of LMIR5/CD300b Amplifies Lipopolysaccharide-Induced Lethal Inflammation in Sepsis

Leukocyte mono-Ig-like receptor 5 (LMIR5, also called CD300b) is an activating receptor expressed in myeloid cells. We have previously demonstrated that T cell Ig mucin 1 works as a ligand for LMIR5 in mouse ischemia/reperfusion injury of the kidneys. In this article, we show that LMIR5 is implicated in LPS-induced sepsis in mice. Notably, neutrophils constitutively released a soluble form of LMIR5 (sLMIR5) through proteolytic cleavage of surface LMIR5. Stimulation with TLR agonists augmented the release of sLMIR5. LPS administration or peritonitis induction increased serum levels of sLMIR5 in mice, which was substantially inhibited by neutrophil depletion. Thus, neutrophils were the main source of LPS-induced sLMIR5 in vivo. On the other hand, i.p. administration of LMIR5-Fc, a surrogate of sLMIR5, bound to resident macrophages (M) and stimulated transient inflammation in mice. Consistently, LMIR5-Fc induced in vitro cytokine production of peritoneal M via its unknown ligand. Interestingly, LMIR5 deficiency profoundly reduced systemic cytokine production and septic mortality in LPS-administered mice, although it did not affect in vitro cytokine production of LPS-stimulated peritoneal M. Importantly, the resistance of LMIR5-deficient mice to LPS- or peritonitis-induced septic death was decreased by LMIR5-Fc administration, implicating sLMIR5 in LPS responses in vivo. Collectively, neutrophil-derived sLMIR5 amplifies LPS-induced lethal inflammation.     

Seizure suppression and neuroprotection by targeting the purinergic P2X7 receptor during status epilepticus in mice

Prolonged seizures [status epilepticus (SE)] constitute a neurological emergency that can permanently damage the brain. SE results from a failure of the normal mechanisms to terminate seizures; in particular, γ-amino butyric acid-mediated inhibition, and benzodiazepine anticonvulsants are often incompletely effective. ATP acts as a fast neurotransmitter via ionotropic ligand-gated P2X receptors. Here we report that SE induced by intra-amygdala kainic acid in mice selectively increased hippocampal levels of P2X7 receptors relative to other P2X receptors. Using transgenic P2X7 reporter mice expressing enhanced green fluorescent protein, we identify dentate granule neurons as the major cell population transcribing the P2X7 receptor after SE. Pretreatment of mice with an intracerebroventricular microinjection of 1.75 nmol A438079, a P2X7 receptor antagonist, reduced seizure duration by 58% and reduced seizure-induced neuronal death by 61%. Injection of brilliant blue G (1 pmol), another selective antagonist, reduced seizure duration by 48% and was also neuroprotective. A438079 was seizure-suppressive when injected shortly after induction of SE, and coinjection of A438079 with lorazepam 60 min after triggering SE, when electrographic seizure-responsiveness to lorazepam had decreased, also terminated SE. Our results suggest that P2X7 receptor antagonists may be a promising class of drug for seizure abrogation and neuroprotection in SE.     

Amelioration of the progression of an atopic dermatitis-like skin lesion by silk peptide and identification of functional peptides

The efficacy of silk peptide in treatment of atopic dermatitis was examined in a picryl chloride-induced atopic dermatitis model in NC/Nga mice. Silk peptide ameliorated the development of atopic dermatitis by lowering the serum IgE concentration. Treatment of cultured spleen cells with silk peptide reduced IgE production by enhancing the production of IFN-γ and reducing the level of IL-4. The functional peptides in the silk peptide were identified as mixture of GAGA sequences containing peptides by mass spectrometry and in vitro assay. Our findings indicate that silk peptide exerts an effect on atopic dermatitis by modulating the Th1/Th2 balance.     

Cytoskeleton alterations induced by Geodia corticostylifera depsipeptides in breast cancer cells

Crude extracts of the marine sponge Geodia corticostylifera from Brazilian Coast have previously shown antibacterial, antifungal, cytotoxic, haemolytic and neurotoxic activities. The present work describes the isolation of the cyclic peptides geodiamolides A, B, H and I (1-4) from G. corticostylifera and their anti-proliferative effects against sea urchin eggs and human breast cancer cell lineages. Its structure-activity relationship is discussed as well. In an initial series of experiments these peptides inhibited the first cleavage of sea urchin eggs (Lytechinus variegatus). Duplication of nuclei without complete egg cell division indicated the mechanism of action might be related to microfilament disruption. Further studies showed that the geodiamolides have anti-proliferative activity against human breast cancer cell lines (T47D and MCF7). Using fluorescence techniques and confocal microscopy, we found evidence that the geodiamolides A, B, H and I act by disorganizing actin filaments of T47D and MCF7 cancer cells, in a way similar to other depsipeptides (such as jaspamide 5 and dolastatins), keeping the normal microtubule organization. Normal cells lines (primary culture human fibroblasts and BRL3A rat liver epithelial cells) were not affected by the treatment as tumor cells were, thus indicating the biomedical potential of these compounds.     

Caissarolysin I (Bcs I), a new hemolytic toxin from the Brazilian sea anemone Bunodosoma caissarum: purification and biological characterization

Two cationic proteins, C1 and C3, were purified to homogeneity from the hemolytic fraction of the venom of Bunodosoma caissarum sea anemone. The purification processes employed gel filtration followed by ion exchange chromatography, being the purity and molecular mass confirmed by SDS-PAGE and mass spectrometry. Protein C1 represented the second major peak of the hemolytic fraction and was previously believed to be a cytolysin belonging to a new class of hemolysins. The C1 protein has a molecular mass of 15495 Da and was assayed for hemolysis, PLA2 activity and acute toxicity in crabs and mice, showing no activity in these assays. It has an amino terminal with no similarity to all known hemolysins and, therefore, should not be considered a toxin, being its function completely unknown. The protein C3 (19757 Da), that also lacks PLA2 activity, was recognized by antiserum against Eqt II and presented high hemolytic activity to human erythrocytes (ED50 of 0.270 microg/ml), being named Caissarolysin I (Bcs I). Its activity was inhibited by pre-incubation with sphingomyelin (SM) and also when in presence of erythrocytes pre-treated with the SMase P2, a phospholipase D from the brown spider Loxosceles intermedia, indicating that SM is the main target of Bcs I. Caissarolysin I is the first hemolysin purified from a sea anemone belonging to the genus Bunodosoma and belongs to the Actinoporin family of sea anemone hemolysins.