Single-step,rapid separation of acidic and basic isoenzymes from commercial horseradish peroxidase

A simple and sensitive high-performance liquid chromatography method with electrochemical detector is described for the determination of free 3-methoxy-4-hydroxyphenylacetic acid (HVA) in human plasma. The method does not involve any extraction, is specific and reproducible, and has the potential to measure serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) simultaneously. The plasma concentration of free HVA in eight normal, healthy adult volunteers was 10.9 ± 4.6 (mean ± SD). In a preliminary study, in one schizophrenic patient the plasma HVA increased twofold after neuroleptic treatment.     

Bioactive polymers XXX. Immobilization of invertase on the diazonium salt of 4-aminobenzoylcellulose

Invertase was immobilized on diazotized 4-aminobenzoylcellulose. The optimum coupling conditions, namely enzyme concentration, time, and pH, were determined. The temperature and pH value for the maximum activity of the immobilized enzyme were determined and the apparent Michaelis constant was estimated.     

Preadipocyte Recruitment in Stromal Vascular Cultures After Depletion of Committed Preadipocytes by Immunocytotoxicity

Glucocorticoids or the glucocorticoid analog dexamethasone (DEX) enhances the differentiation of preadipocytes in the presence of insulin and influences preadipocyte proliferation. The purpose of the present study was to determine if DEX can induce the recruitment of preadipocytes. Using monoclonal antibodies for complement-mediated cytotoxicity, preadipocytes were removed from porcine stromal vascular (S-V) cell cultures. Our experiments demonstrated for the first time that after removal of preadipocytes by cytotoxicity, preadipocytes or fat cells could be induced by DEX or DEX plus insulin but not by insulin alone. However, many more fat cells were induced (258 ± 15/unit area) when DEX was added with fetal bovine serum (FBS) followed with insulin treatment, compared to DEX with insulin (21.3 ± 5.1/ unit area) after removal of preadipocytes. Immunocyto-chemistry with AD-3, a preadipocyte marker, showed that DEX with FBS for 3 days after seeding (i.e., the proliferation phase) produced many more preadipocytes (AD-3 positive, 223 ± 45/unit area) than FBS alone (10.5 ± 1.4/unit area). Bromodeoxyuridine (BrdU) incorporation assays demonstrated that the efficiency of DEX with FBS (i.e., during proliferation) was mitosis dependent. Accordingly, we conclude that: porcine S-V cultures contain preadipocytes at different stages of differentiation and that DEX induced early preadipocyte differentiation depends on mitosis.     

A peculiar lymph node anti-carcinoma reaction.

A case of a laryngeal extensive carcinoma determining a severe obstruction is reported, where the development of a monstrous adenopathy is followed by the regression of the initial tumour until complete laryngoscopical disappearance, as well as of obstructive and general symptoms. Cytological and histological examinations of the above-mentioned lymph node demonstrated (besides metastatic cells) a peculiar cellular reaction, similar to rhinoscleroma, which represented an original anti-carcinoma defensive mode. The medical importance of this very rare case is discussed and the probable immune origin of this reactive cellular complex is explained by analogy with "Hodgkinom", where granuloma are the immune response of the body against Sternberg-Reed cell.     

Isolation of Thiomonas thermosulfatus Strain 51, a Species Capable of Coupling Biogenic Pyritization with Chemiosmotic Energy Transduction

The precipitation of iron sulfides potentially offers enough energy and reducing power to sustain life but organisms harnessing this reaction have not to our knowledge been previously described. We isolated a bacterial strain, capable of forming the iron sulfide minerals troilite (FeS), greigite (Fe₃S₄), and pyrite (FeS₂), from subsurface, microbial mats in Mangalia, Romania. This strain, most closely related to strains of Thiomonas sp., forms pyrite only if the redox conditions remain negative (< ?60 mV), sulfides are provided continually (≈1 mM), and the concentration of iron remains low (≤ 0.08 mM) but constant. Pyrite formation by this microbial strain is proposed as an example of biologically controlled mineralization because it is controlled by uncouplers of oxidative phosphorylation, it is larger in living than in dead cells, it is additive (controlled less by the amount of cell surfaces and more by reagents), and it results in the formation of ATP. This study indicates that precipitation and crystal formation can represent an energy resource for life and provides support for the “iron-sulfide world hypothesis” regarding the early evolution of life on Earth.     

Occurrence of species of the genus Pityophthorus Eichhoff (Coleoptera,Curculionidae, Scolytinae) in?the?province of Quebec,Canada

Twig beetles in the genus Pityophthorus Eichhoff, 1864 include more than 300 species worldwide, with maximum diversity in tropical and subtropical regions. To date, approximately 50 species of Pityophthorus have been recorded in Canada, and these species are associated mainly with coniferous trees. Since 1981, no comprehensive study on this difficult taxonomic group has been conducted in Quebec, Canada, most likely due to their limited significance as forest pests. Based on data gathered from five years of field sampling in conifer seed orchards and compiled from various entomological collections, the distribution of Pityophthorus species in Quebec is presented. Approximately 291 new localities were recorded for the Pityophthorus species. Five species-group taxa, namely Pityophthorus puberulus (LeConte, 1868), Pityophthorus pulchellus pulchellus Eichhoff, 1869, Pityophthorus pulicarius (Zimmermann, 1868), Pityophthorus nitidus Swaine, 1917,and Pityophthorus cariniceps LeConte&Horn, 1876 were the most widespread. In contrast, Pityophthorus consimilis LeConte, 1878, Pityophthorus intextus Swaine, 1917, Pityophthorus dentifrons Blackman, 1922, Pityophthorus ramiperda Swaine, 1917, and Pityophthorus concavus Blackman, 1928 display a notably limited distribution. In addition, the first distribution records of Pityophthorus intextus and Pityophthorus biovalis Blackman, 1922 are furnished, and the subspecies Pityophthorus murrayanae murrayanae Blackman, 1922is reported from Quebec for the second time. Moreover, distribution maps are provided for all Pityophthorus species recorded in the province of Quebec.     

Interaction of piroxicam with bovine serum albumin investigated by spectroscopic,calorimetric and computational molecular methods

Abstract

The binding of drugs to serum proteins is governed by weak non-covalent forces. In this study, the nature and magnitude of the interactions between piroxicam (PRX) and bovine serum albumin (BSA) was assessed using spectroscopic, calorimetric and computational molecular methods. The fluorescence data revealed an atypical behavior during PRX and BSA interaction. The quenching process of tryptophan (Trp) by PRX is a dual one (approximately equal static and dynamic quenched components). The FRET results indicate that a non-radiative transfer of energy occurred. The association constant and the number of binding sites indicate moderate PRX and BSA binding. The competitive binding study indicates that PRX is bound to site I from the hydrophobic pocket of subdomain IIA of BSA. The synchronous spectra showed that the microenvironment around the BSA fluorophores and protein conformation do not change considerably. The Trp lifetimes revealed that PRX mainly quenches the fluorescence of Trp-213 situated in the hydrophobic domain. The CD and DSC investigation show that addition of PRX stabilizes the protein structure. ITC results revealed that BSA-PRX binding involves a combination of electrostatic, hydrophobic and hydrogen interactions. The analysis of the computational data is consistent with the experimental results. This thorough investigation of the PRX-BSA binding may provide support for other studies concerning moderate affinity drugs with serum protein.

Communicated by Ramaswamy H. Sarma     

Synthesis and characterization of N-(2-aminoethyl)-2-acetamidyl gellan gum with potential biomedical applications

N-(2-aminoethyl)-2-acetamidyl gellan gum (GCM-EDA) was prepared by carboxymethylation (via nucleophilic substitution of primary hydroxyl groups of the β-d-glucose unit of gellan gum, in the presence of alkali and chloroacetic acid) and reaction with tert-butyl N-(2-aminoethyl) carbamate (N-Boc-EDA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as an activator, followed by deprotection with trifluoroacetic acid. The structural confirmation and characterization of N-(2-aminoethyl)-2-acetamidyl gellan gum was performed by spectroscopic, rheological and thermogravimetric analysis, and in vitro tests showed a lack of cytotoxicity which is indicative of the potential of this material to be used in biomedical applications.     

A 323-year long reconstruction of drought for SW Romania based on black pine (Pinus Nigra) tree-ring widths

Increase in temperature and decrease in precipitation pose a major future challenge for sustainable ecosystem management in Romania. To understand ecosystem response and the wider social consequences of environmental change, we constructed a 396-year long (1615–2010) drought sensitive tree-ring width chronology (TRW) of Pinus nigra var. banatica (Georg. et Ion.) growing on steep slopes and shallow organic soil. We established a statistical relationship between TRW and two meteorological parameters—monthly sum of precipitation (PP) and standardised precipitation index (SPI). PP and SPI correlate significantly with TRW (r?=?0.54 and 0.58) and are stable in time. Rigorous statistical tests, which measure the accuracy and prediction ability of the model, were all significant. SPI was eventually reconstructed back to 1688, with extreme dry and wet years identified using the percentile method. By means of reconstruction, we identified two so far unknown extremely dry years in Romania—1725 and 1782. Those 2 years are almost as dry as 1946, which was known as the “year of great famine.” Since no historical documents for these 2 years were available in local archives, we compared the results with those from neighbouring countries and discovered that both years were extremely dry in the wider region (Slovakia, Hungary, Anatolia, Syria, and Turkey). While the 1800–1900 period was relatively mild, with only two moderately extreme years as far as weather is concerned, the 1900–2009 period was highly salient owing to the very high number of wet and dry extremes—five extremely wet and three extremely dry events (one of them in 1946) were identified.