Inhibition of carbonic anhydrase isoforms I,II, IX and XII with secondary sulfonamides incorporating benzothiazole scaffolds

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the fundamental reaction of CO₂ hydration in all living organisms, being actively involved in the regulation of a plethora of patho/physiological conditions. A series of benzothiazole-based sulfonamides were synthesized and tested as possible CA inhibitors. Their inhibitory activity was assessed against the cytosolic human isoforms hCA I and hCA II and the transmembrane hCA IX and hCA XII. Several of the investigated derivatives showed interesting inhibition activity and selectivities for inhibiting hCA IX and hCA XII over the off-target ones hCA I and hCA II. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds, within the active site of hCA IX.     

Regulation of rat liver phosphatidylethanolamine N-methyltransferase by cytosolic factors. Examination of a role for reversible protein phosphorylation

The nature of cytosolic factors which modulate the activity of rat liver phosphatidylethanolamine (PE) methyltransferase was investigated. The combined additions of cytosol, Mg X ATP, and NaF to incubations with rat liver microsomes produced a 1.6-fold activation of the methyltransferase at pH 9.2 and a 1.3-fold stimulation at pH 7.0. Nonhydrolyzable 5'-adenylylimidodiphosphate could not substitute for ATP, although GTP could. The activation was time dependent, stable to reisolation of the microsomes by ultracentrifugation, and partially preventable by other cytosolic components. Despite these indications that PE methyltransferase might be a substrate for cytosolic protein kinases, cAMP and Ca2+-calmodulin exerted little influence on the activation reaction. Furthermore, microsomal PE methyltransferase activity was unaffected by purified preparations of cAMP-dependent protein kinase, calmodulin-dependent protein kinase, and casein kinase II, nor was methyltransferase activity influenced by the purified catalytic subunits of protein phosphatases 1 and 2A. Cytosol also contained inhibitors of PE methyltransferase which could overcome the Mg X ATP X NaF-mediated activation of the enzyme, but were not affected by the thermostable phosphatase inhibitors 1 and 2. Part of this inhibitory activity (apparent molecular mass of 15 X 10(3) daltons) was insensitive to trypsin and chymotrypsin, stimulated by Mn2+, and partly inhibited by NaF. Therefore, regulation of methyltransferase by reversible phosphorylation, while still a tenable hypothesis, is apparently more complex than previously proposed.     

Mechanisms driving the specificity of a myrmecophyte–ant association

In the understory of pristine Guianese forests, the myrmecophyte Hirtella physophora almost exclusively shelters colonies of the plant-ant Allomerus decemarticulatus in its leaf pouches. We experimentally tested three non-mutually exclusive hypotheses concerning phenomena that can determine the species specificity of this association throughout the foundation stage of the colonies: (1) interspecific competition results in the overwhelming presence of A. decemarticulatus queens or incipient colonies; (2) exclusion filters prevent other ant species from entering the leaf pouches; and (3) host-recognition influences the choice of founding queens, especially A. decemarticulatus . Neither interspecific competition, nor the purported exclusion filters that we examined play a major role in maintaining the specificity of this association. Unexpectedly, the plant trichomes lining the domatia appear to serve as construction material during claustral foundation rather than as a filter. Finally, A. decemarticulatus queens are able to identify their host plant from a distance through chemical and/or visual cues, which is rarely demonstrated in studies on obligatory ant–plant associations. We discuss the possibility that this specific host-recognition ability could participate in shaping a compartmentalized plant-ant community where direct competition between ant symbionts is limited.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 90–97.     

The Iberian Peninsula: ancient history of a hot spot of mite harvestmen (Arachnida: Opiliones: Cyphophthalmi: Sironidae) diversity

The Iberian Peninsula represents a hot spot of cyphophthalmid (mite harvestman) disparity, with four of the eight genera currently recognized in the family Sironidae represented in the region – a generic diversity and morphological disparity not found in any other region of the World so far. From these, two genera (Iberosiro and Odontosiro) are monotypic, and are restricted to the western side of the peninsula. Parasiro is restricted to the north‐east region, from the Catalonian Coastal Ranges and both sides of the Eastern Pyrenees, in areas where the annual rainfall surpasses 1000 mm, and mostly restricted to areas with Paleozoic and Variscan rocks, with other species of the genus extending to Corsica, Sardinia, and the Italian Peninsula. A second species of the genus Paramiopsalis, Paramiopsalis eduardoi sp. nov. from Fragas do Eume, is described here along with a re‐diagnosis of the genus. Paramiopsalis species, together with Odontosiro, inhabit the north‐west corner of the Iberian Peninsula, an area with some of the highest recorded annual rainfall, and with Paleozoic rocks from the Iberian Massif or Variscan granitoid rocks. A phylogenetic analysis of the members of the family Sironidae using four molecular markers, despite not including all of the Iberian genera, clearly shows the non‐monophyly of the Iberian Cyphophthalmi, indicating that the Iberian Peninsula is home to multiple ancient lineages of mite harvestmen. The two Paramiopsalis species form a sister clade to the Balkan genus Cyphophthalmus, whereas Parasiro constitutes the first lineage of the sironids represented.     

Differential in vitro inhibition of polyphenoloxidase from a wild edible mushroom Lactarius salmonicolor

The polyphenol oxidase (LsPPO) from a wild edible mushroom Lactarius salmonicolor was purified using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. At the optimum pH and temperature, the K(M) and V(Max) values of LsPPO towards catechol, 4-methylcatechol and pyrogallol were determined as 0.025 M & 0.748 EU/mL, 1.809 x 10(- 3) M & 0.723 EU/mL and 9.465 x 10(- 3) M & 0.722 EU/mL, respectively. Optimum pH and temperature values of LsPPO for the three substrates above ranged between the pH 4.5-11.0 and 5-50 degrees C. Enzyme activity decreased due to heat denaturation with increasing temperature. Effects of a variety of classical PPO inhibitors were investigated opon the activity of LsPPO using catechol as the substrate. IC(50) values for glutathione, p-aminobenzenesulfonamide, L-cysteine, L-tyrosine, oxalic acid, beta-mercaptoethanol and syringic acid were determined as 9.1 x 10(- 4), 2.3 x 10(- 4) M, 1.5 x 10(- 4) M, 3.8 x 10(- 7) M, 1.2 x 10(- 4) M, 4.9 x 10(- 4) M, and 4 x 10(- 4) M respectively. Thus L-tyrosine was by far the most effective inhibitor. Interestingly, sulfosalicylic acid behaved as an activator of LsPPO in this study.     

Effect of transport and storage temperature of ovaries on in vitro maturation of bitch oocytes

In this study, the effects of ovary transport and storage temperature on in vitro maturation of bitch oocytes were investigated. Ovaries were collected from 23 mature bitches and one randomly selected ovary of each pair (n=23 pairs) was transported in physiologic saline at 4 degrees C, while the other one at 35-38 degrees C for 2-4h. A total of 316 cumulus oocyte complexes (COCs) were obtained from the 4 degrees C group and 301 COCs from the 35-38 degrees C group. All COCs were matured in modified synthetic oviduct fluid (mSOF) supplemented with follicle stimulating hormone (FSH), essential and non-essential amino acids at 38 degrees C in a humidified 5% CO2, 5% O2, and 90% N2 atmosphere for 72 h. At the end of the in vitro maturation period, nuclear maturation of oocytes was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), metaphase II (MII), undetermined nuclear maturation (UDNM), and MI+MII. The nuclear maturation rates to MI, MII, and MI+MII stages were 60.44%, 10.75%, and 71.20% in the 4 degrees C group and 37.20%, 7.64%, and 45.85% in the 35-38 degrees C group, respectively. The data demonstrated that oocytes obtained from ovaries transported at 4 degrees C had higher maturation rates than from the ones transported at 35-38 degrees C (p<0.001).     

Developing a realistic sexual network model of chlamydia transmission in Britain

Background  

A national chlamydia screening programme is currently being rolled out in the UK and other countries. However, much of the epidemiology remains poorly understood. In this paper we present a stochastic, individual based, dynamic sexual network model of chlamydia transmission and its parameterisation. Mathematical models provide a theoretical framework for understanding the key epidemiological features of chlamydia: sexual behaviour, health care seeking and transmission dynamics.