Zero spontaneous curvature and its effects on lamellar phase morphology and vesicle size distributions

Equimolar mixtures of dodecyltrimethylammonium chloride (DTAC) and sodium octyl sulfonate (SOSo) show a vesicle phase at >99 wt % water and a single, fluid lamellar phase for water fractions below 80 wt %. This combination is consistent with the bilayer bending elasticity kappa approximately k(B)T and zero bilayer spontaneous curvature. Caillé line shape analysis of the small-angle X-ray scattering from the lamellar phase shows that the effective kappa depends on the lamellar d spacing consistent with a logarithmic renormalization of kappa, with kappa(o) = (0.8 +/- 0.1)k(B)T. The vesicle size distribution determined by cryogenic transmission electron microscopy is well fit by models with zero spontaneous curvature to give (kappa + (kappa/2)) = (1.7 +/- 0.1)k(B)T, resulting in kappa = (1.8 +/- 0.2)k(B)T. The positive value of kappa and the lack of spontaneous curvature act to eliminate the spherulite defects found in the lamellar gel phases found in other catanionic mixtures. Current theories of spontaneous bilayer curvature require an excess of one or more components on opposite sides of the bilayer; the absence of such an excess at equimolar surfactant ratios explains the zero spontaneous curvature.     

Racemic iron(III) and cobalt(III) complexes containing a new pentadentate "helmet" phthalocyaninato ligand

Solvothermal reactions of iron(II) acetate tetrahydrate and cobalt(II) acetate tetrahydrate with 1,2-dicyanobenzene in methanol solution result in the formation of racemic six-coordinate iron(III) and cobalt(III) complexes, respectively, with a new bicyclic pentadentate 14,28-[1,3-diiminoisoindolinato]phthalocyaninato ligand.     

Vibrationally mediated photodissociation of ammonia: the influence of N-H stretching vibrations on passage through conical intersections

Velocity map ion imaging of the H atoms formed in the photodissociation of vibrationally excited ammonia molecules measures the extent of adiabatic and nonadiabatic dissociation for different vibrations in the electronically excited state. Decomposition of molecules with an excited symmetric N-H stretch produces primarily ground state NH(2) along with a H atom. The kinetic energy release distribution is qualitatively similar to the ones from dissociation of ammonia excited to the electronic origin or to several different levels of the bending vibration and umbrella vibration. The situation is very different for electronically excited molecules containing a quantum of antisymmetric N-H stretch. Decomposition from that state produces almost solely electronically excited NH(2)*, avoiding the conical intersection between the excited state and ground state surfaces. These rotationally resolved measurements agree with our previous inferences from lower resolution Doppler profile measurements. The production of NH(2)* suggests that the antisymmetric stretching excitation in the electronically excited molecule carries it away from the conical intersection that other vibrational states access.     

The descriptions of new microanatomical structures of the male reproductive system and sperm of Myschocyttarus cassununga (Hymenoptera: Vespidae)

The male reproductive system of Mischocyttarus cassununga consists of two testes, each one with three follicles, as occurs in most Vespidae. The seminal vesicle is divided in two chambers, separated by a constriction, so that the anterior locus is a little larger. In the testicular follicles, the spermatozoa are organized in cysts, with approximately 128 per cyst, where the nuclei are oriented toward the follicle center. The spermatozoa of M. cassununga is about 97 μm in length, which makes them the shortest sperm described for Vespidae. Sperm ultrastructure of M. cassununga is very similar of the others Vespidae. But, despite these similarities, the bilobated mitochondrial derivative represents an autapomorphy for M. cassununga. The subdivision of the seminal vesicle has never been observed in any other Vespidae. Thus, this study supports the validity of insect sperm morphology as a tool for phylogenetic analysis within Hymenoptera.     

Polymeric prodrugs of mitomycin C

Poly-[N-(2-hydroxyethyl)-L-glutamine] (PHEG) prodrugs of the cytotoxic agent Mitomycin C were synthesized using peptidyl spacers to link the drug to the polymeric carrier. The influence on the length and detailed structure of the oligopeptide on the rate of drug release was investigated in buffer, in the presence of lysosomal enzymes (tritosomes, cathepsin B and D) and metalloprotease type IV collagenase. It was observed that tetra- and hexapeptide based conjugates generally release Mitomycin C (MMC) more effectively than tripeptide derivatives. The gly-phe-ala-leu conjugate released MMC very rapidly both in presence of lysosomal enzymes and collagenase IV. Only in the presence of the aspartic protease cathepsin D, the gly-phe-leu-gly-phe-leu derivative turned out to be a better substrate. In vivo studies against C26 solid tumour bearing mice suggest that PHEG-spacer-MMC conjugates act as prodrugs of MMC: antitumour efficacy of the macromolecular prodrugs was better than free MMC both in inhibition of tumour growth and increasing survival.     

Inhibitory Role of Berberine,an Isoquinoline Alkaloid,on NLRP3 Inflammasome Activation for the Treatment of Inflammatory Diseases

The pyrin domain-containing multiprotein complex NLRP3 inflammasome, consisting of the NLRP3 protein, ASC adaptor, and procaspase-1, plays a vital role in the pathophysiology of several inflammatory disorders, including neurological and metabolic disorders, chronic inflammatory diseases, and cancer. Several phytochemicals act as promising anti-inflammatory agents and are usually regarded to have potential applications as complementary or alternative therapeutic agents against chronic inflammatory disorders. Various in vitro and in vivo studies have reported the anti-inflammatory role of berberine (BRB), an organic heteropentacyclic phytochemical and natural isoquinoline, in inhibiting NLRP3 inflammasome-dependent inflammation against many disorders. This review summarizes the mechanism and regulation of NLRP3 inflammasome activation and its involvement in inflammatory diseases, and discusses the current scientific evidence on the repressive role of BRB on NLRP3 inflammasome pathways along with the possible mechanism(s) and their potential in counteracting various inflammatory diseases.     

Response of MCF-7 Breast Cancer Cells Overexpressed with P-Glycoprotein to Apoptotic Induction after Photodynamic Therapy

Multidrug resistance (MDR) has posed a significant threat to cancer treatment and has led to the emergence of a new therapeutic regime of photodynamic therapy (PDT) to curb the menace. The PDT modality employs a photosensitiser (PS), excited at a specific wavelength of light to kill cancer cells. In the present study, we used a zinc phthalocyanine tetrasulfonic acid PS to mediate the photodynamic killing of MCF-7 cells overexpressed with P-glycoprotein (P-gp) and investigate the response to cell death induction. After photodynamic treatment, MCF-7 cells undergo cell death, and indicators like Annexin V/PI staining, DNA fragmentation, and measurement of apoptotic protein expression were investigated. Results showed increased externalisation of phosphatidylserine protein, measured as a percentage in flow cytometry indicative of apoptotic induction. This expression was significant (p < 0.006) for the untreated control cells, and there was no detection of DNA fragments after a laser fluence of 20 J/cm². In addition, a statistically significant difference (p < 0.05) was seen in caspase 8 activity and Bax protein expression. These findings were indicative of apoptotic induction and thus seem to represent the extrinsic apoptotic pathway. This study shows the role of PDT in the treatment of a resistant phenotype breast cancer.