Combination of two chromophores: synthesis and PDT application of porphyrin-pentamethinium conjugate

A general method for the synthesis of a novel porphyrin with pentamethine periphery substitution is described. The combination of two chromophoric systems, a porphyrin macrocycle and a polymethine moiety was achieved by transformation of tetrapyridyl porphyrin. The synthetic strategy included conversion of the tetrapyridyl porphyrin to its corresponding 2,4-dinitrophenylpyridinuim salt, which was subsequently converted to tetrakis(meso-pentamethinium salt) on the porphyrin core. This novel porphyrin exhibited PDT properties as manifested by the induction of apoptosis in the myeloid cell line HL-60 and the effective reduction of amelanotic melanoma in nude mice.     

Effect of coenzyme Q10 and vitamin E on brain energy metabolism in the animal model of Huntington's disease

The neuropathological and clinical symptoms of Huntington's disease (HD) can be simulated in animal model with systemic administration of 3-nitropropionic acid (3-NP). Energy defects in HD could be ameliorated by administration of coenzyme Q(10) (CoQ(10)), creatine, or nicotinamid. We studied the activity of creatine kinase (CK) and the function of mitochondrial respiratory chain in the brain of aged rats administered with 3-NP with and without previous application of antioxidants CoQ(10)+vitamin E. We used dynamic and steady-state methods of in vivo phosphorus magnetic resonance spectroscopy ((31)P MRS) for determination of the pseudo-first order rate constant (k(for)) of the forward CK reaction, the phosphocreatine (PCr) to adenosinetriphosphate (ATP) ratio, intracellular pH(i) and Mg(i)(2+) content in the brain. The respiratory chain function of isolated mitochondria was assessed polarographically; the concentration of CoQ(10) and alpha-tocopherol by HPLC. We found significant elevation of k(for) in brains of 3-NP rats, reflecting increased rate of CK reaction in cytosol. The function of respiratory chain in the presence of succinate was severely diminished. The activity of cytochromeoxidase and mitochondrial concentration of CoQ(10) was unaltered; tissue content of CoQ(10) was decreased in 3-NP rats. Antioxidants CoQ(10)+vitamin E prevented increase of k(for) and the decrease of CoQ(10) content in brain tissue, but were ineffective to prevent the decline of respiratory chain function. We suppose that increased activity of CK system could be compensatory to decreased mitochondrial ATP production, and CoQ(10)+vitamin E could prevent the increase of k(for) after 3-NP treatment likely by activity of CoQ(10) outside the mitochondria. Results of our experiments contributed to elucidation of mechanism of beneficial effect of CoQ(10) administration in HD and showed that the rate constant of CK is a sensitive indicator of brain energy disorder reflecting therapeutic effect of drugs that could be used as a new in vivo biomarker of neurodegenerative diseases.     

Inhibitory Effects of Some Spice and Herb Extracts Against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii

Seventeen spice and medicinal plant extracts (methanol and chloroform) were assayed for their antimicrobial activity against Arcobacter butzleri, A. cryaerophilus, and A. skirrowii. In general, all of the tested extracts were able, to a different extent, to inhibit the growth of the selected Arcobacter species. Cinnamon, bearberry, chamomile, sage and rosemary extracts showed strong antimicrobial activity toward arcobacter strains tested. Overall, the methanol extracts showed better activity than the chloroform extracts (P < 0.05); however, enhanced antibacterial activity of chloroform extracts of cinnamon and rosemary has been observed in comparison with their methanol counterparts. The inhibitory dose of the most active extracts (the diameter of zone of inhibition ≥ 20 mm) was determined using the disc-diffusion method as well.     

Anion uptake in halorhodopsin from Natromonas pharaonis studied by FTIR spectroscopy: consequences for the anion transport mechanism

The uptake of chloride, bromide, iodide, nitrate, and azide by anion-depleted blue halorhodopsin from Natronobacterium pharaonis has been followed by FTIR difference spectroscopy using an ATR sampling device. The spectra are compared with the spectrum of the O intermediate obtained by time-resolved FTIR studies of the photocycle. It is demonstrated that anion-free blue halorhodopsin can be identified with the O intermediate and, thus, that the decay of O is due to the passive uptake of the anion. The great similarity of the anion-binding spectra and their identity in the case of the monoatomic anions indicate a rather unspecific binding site for the different anions dominated by electrostatic interactions. Comparing spectra obtained with 15N nitrate and unlabeled nitrate, the NO-stretching bands could be identified. The small splitting and the small IR intensity of those bands indicate a rather nonpolar binding site with a rather isotropic influence on the nitrate, in contrast to aqueous nitrate. In further experiments on the photocycle of blue halorhodopsin, the all-trans --> 13-cis isomerization can be clearly identified. Up to 100 micros, the isomerization-induced structural changes deduced from amide I changes are similar to those occurring during the anion-transporting photocycle. Compared to these, the molecular changes involved in the release and their reversion during the uptake of anions are considerably larger. They can be reached via two pathways: (1) by reducing the anion concentration and (2) transiently during the anion-transporting photocycle with the formation of the precursor of O with O conformation. Consequences of the anion transport mechanism are discussed.     

Synthesis,characterization and biological activity of ring-substituted 6-benzylamino-9-tetrahydropyran-2-yl and 9-tetrahydrofuran-2-ylpurine derivatives

In an attempt to improve specific biological functions of cytokinins routinely used in plant micropropagation, 33 6-benzylamino-9-tetrahydropyran-2-ylpurine (THPP) and 9-tetrahydrofuran-2-ylpurine (THFP) derivatives, with variously positioned hydroxy and methoxy functional groups on the benzyl ring, were prepared. The new derivatives were prepared by condensation of 6-chloropurine with 3,4-dihydro-2H-pyran or 2,3-dihydrofuran and then by the condensation of these intermediates with the corresponding benzylamines. The prepared compounds were characterized by elemental analyses, TLC, HPLC, melting point determinations, CI+ MS and ¹H NMR spectroscopy. The cytokinin activity of all the prepared derivatives was assessed in three classical cytokinin bioassays (tobacco callus, wheat leaf senescence and Amaranthus bioassay). The derivatives 6-(3-hydroxybenzylamino)-9-tetrahydropyran-2-ylpurine (3) and 6-(3-hydroxybenzylamino)-9-tetrahydrofuran-2-ylpurine (23) were selected, because of the high affinity of their parent compound meta-topolin (mT, 6-(3-hydroxybenzylamino)purine) to cytokinin receptors, as model compounds for studying their perception by the receptors CRE1/AHK4 and AHK3 in a bacterial assay. Both receptors perceived these two derivatives less well than they perceived the parent compound. Subsequently, the susceptibility of several new derivatives to enzyme degradation by cytokinin oxidase/dehydrogenase was studied. Substitution of tetrahydropyran-2-yl (THP) at the N⁹ position decreased the turnover rates of all new derivatives to some extent. To provide a practical perspective, the cytotoxicity of the prepared compounds against human diploid fibroblasts (BJ) and the human cancer cell lines K-562 and MCF-7 was also assayed in vitro. The prepared compounds showed none or marginal cytotoxicity compared to the corresponding N⁹-ribosides. Finally, the pH stability of the two model compounds was assessed in acidic and neutral water solutions (pH 3–7) by high-performance liquid chromatography (HPLC).     

Haplotyping barley <Emphasis Type="Italic">bmy1</Emphasis> using the SNaPshot assay

The allelic status at bmy1, which encodes the enzyme β-amylase 1 in the barley grain, has an important influence over a cultivar’s malting quality. Changes in the malting process have been responsible for the need to improve the thermostability of this enzyme. We have compared a published bmy1 haplotyping assay based on TDI-FRET (template-directed dye-terminator incorporation fluorescence resonance energy transfer) with a SNaPshot protocol by jointly analysing a set of 21 cultivars of known haplotype. The two methods gave the same result, but the SNaPshot assay was easier to interpret. The SNaPshot assay was therefore used to haplotype the Czech malting barley core collection with respect to bmy1. The old Czech cultivar Kasticky was the only entry identified as carrying the high thermostability haplotype, with the remainder carrying either the intermediate or the low thermostability haplotypes. Older materials were the most variable in terms of bmy1 haplotype, but the majority carried the intermediate type. Most of the descendants of cv. Diamant carried the low thermostability haplotype. The most recently released cultivars recommended for the brewing of Czech beer tend to carry the intermediate allele.     

Effect of poly(amido)amine (PAMAM) G4 dendrimer on heart and liver mitochondria in an animal model of diabetes

Diabetes‐induced injury related to hyperglycaemia is associated with impaired function of mitochondria. Regardless of their cytotoxicity, PAMAM [poly(amido)amine] G4 dendrimers lower plasma glucose and suppress long‐term markers of diabetic hyperglycaemia in experimental diabetes. In the present study, we aimed at verifying whether such modulatory effects of PAMAM G4 (0.5 μmol/kg of body weight daily for 60 days) may contribute to improved respiration in heart and liver mitochondria from streptozotocin‐diabetic rats. PAMAM G4 alleviated long‐term markers of hyperglycaemia and reduced blood and tissue lipophilic antioxidants in diabetic animals, but did not restore mitochondrial function. In hearts, but not livers, dendrimers further reduced respiratory function and oxidative phosphorylation. Thus ameliorating effects of PAMAM G4 on glycation and glycoxidation in experimental diabetes are not sufficient to restore the impaired mitochondrial function in diabetes.     

Isolation of<Emphasis Type="Italic">Arcobacter butzleri</Emphasis> and<Emphasis Type="Italic">A. cryaerophilus</Emphasis> in samples of meats and from meat-processing plants by a culture technique and detection by PCR

A pilot survey of sources of contamination with arcobacters (representing a potential risk for humans) was done in a wide range of samples involved various kinds of meat (beef, pork, meat products, chilled chickens, etc.) from a retail level and domestic farming. Sanitary practices in slaughterhouses and production lines were checked in two different plants (a beef and pork production and a chicken processing plant). The method is based on a selective enrichment to isolate suspect strains, in combination with a PCR technique specific for arcobacters. The choice of a suitable enrichment broth and a plating agar was made with the use of pure bacterial strains and by means of real meat samples seeded with Arcobacter butzleri. The PCR technique was optimized to allow differentiation of a 1223 bp product, typical of the genus Arcobacter, and a product of 686 bp, specific for A. butzleri a total number of 198 samples were tested, of that 33 (17%) were found to be positive for the genus Arcobacter but only 22 (11%) for A. butzleri.