Could the transcription factor AtnN coordinating the aspercryptin secondary metabolite gene cluster in Aspergillus nidulans be a global regulator?

Products of dormant secondary metabolite gene clusters of fungal genomes can be exploited for medical purposes as bioactive agents. These clusters can be switched on under oxidative stress and may endow fungi with a versatile chemical armory in a competitive niche. In Aspergillus nidulans, the aspercryptin gene cluster, including the synthase [atnA (AN7884)] and its transcription factor (atnN), was activated under menadione sodium bisulfite (MSB) treatment.

Taylor-Aris Dispersion-Assisted Mass Spectrometry for the Analysis of Native Proteins.

As has recently been shown, Taylor-Aris dispersion-assisted mass spectrometry (TADA-MS) can offer direct injection MS determinations in fields where the targets of the analyses are large molecules present in a matrix that would otherwise cause serious interferences. In the present study, we demonstrated the exceptional utility of TADA-MS in native protein analysis: (i) a dramatic improvement in detection sensitivity was found due to its ability to strongly reduce matrix interferences, (ii) more "native-like" conditions can be used during analyses, (iii) the direct injection of non-MS-compatible matrices is allowed into MS, and (iv) a considerable simplification and economization of the workflow is ensured. We investigated the behavior of different types of proteins and protein complexes present under native conditions, demonstrating the unambiguous benefits and simplicity of the method.

Extending the investigation of 4-thiazolidinone derivatives as potential multi-target ligands of enzymes involved in diabetes mellitus and its long-term complications: A study with pancreatic α-amylase.

Diabetes mellitus is a multifactorial disease, which is frequently complicated by the development of hyperglycaemia-induced chronic complications. The therapy of diabetes mellitus often requires combinations of two or more drugs in order both to control glycaemic levels and to prevent hyperglycaemia-induced dangerous affairs. The application of multi-target agents, which are able to control simultaneously several pathogenic mechanisms, represents a useful alternative and, in fact, their discovery is a pursued aim of the research.

Colorado potato beetle alpha-amylase: Purification, action pattern and subsite mapping for exploration of active centre.

Colorado potato beetle is an invasive insect herbivore and one of the most challenging agricultural pests globally. This study is the first characterization of the active centre of Colorado potato beetle (Leptinotarsa decemlineata) α-amylase (LdAmy). Bond cleavage frequency values for LdAmy were determined by HPLC product analysis on a chromophore labelled maltooligomer substrate series.

Gallotannins are non-specific inhibitors of α-amylase: Aggregates are the active species taking part in inhibition.

The versatile biological activity of gallotannins has been investigated for a long time, including their use as α-amylase inhibitors for the treatment of diabetes and its complications. The effectiveness of gallotannins on a wide range of enzymes refers to promiscuity. We proved that gallotannins are non-specific promiscuous α-amylase inhibitors, which exert their effect through their aggregates.

Wild Strawberry, Blackberry, and Blueberry Leaf Extracts Alleviate Starch-Induced Hyperglycemia in Prediabetic and Diabetic Mice.

Intestinal -glucosidase and -amylase break down nutritional poly- and oligosaccharides to monosaccharides and their activity significantly contributes to postprandial hyperglycemia. Competitive inhibitors of these enzymes, such as acarbose, are effective antidiabetic drugs, but have unpleasant side effects. In our ethnopharmacology inspired investigations, we found that wild strawberry (), blackberry (), and European blueberry () leaf extracts inhibit -glucosidase and -amylase enzyme activity and are effective in preventing postprandial hyperglycemia .

Characterization of gfdB, putatively encoding a glycerol 3-phosphate dehydrogenase in Aspergillus nidulans.

The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB.

Synthesis of New Series of 2--(β-D-glucopyranosyl)-Pyrimidines and Their Evaluation as Inhibitors of Some Glycoenzymes.

Despite the substantial interest in -glycosyl heterocycles as mimetics of biologically active native glycans, the appearance of -glycopyranosyl derivatives of six-membered heterocycles, both in synthetic and biological contexts, is rather scarce. As part of our ongoing research program aimed at preparing hitherto barely known 2--glycopyranosyl pyrimidines, the goal of the present study was to synthesize new 5-mono- and multiply substituted derivatives of this compound class. Thus, 2--(β-D-glucopyranosyl)-5,6-disubstituted-pyrimidin-4(3)-ones and 4-amino-2--(β-D-glucopyranosyl)-5,6-disubstituted-pyrimidines were prepared by base-mediated cyclocondensations of -perbenzylated and -unprotected -(β-D-glucopyranosyl) formamidine hydrochlorides with methylenemalonic acid derivatives.

Studies on the reversible enzyme reaction of rabbit muscle glycogen phosphorylase b using isothermal titration calorimetry.

Glycogen phosphorylase enzymes (GP) catalyse reversible reactions; the glucose transfer from glycogen to inorganic phosphate (P, phosphorolysis) or the reverse glucose transfer from glucose-1-phosphate (G-1-P) to glycogen (synthesis). Rabbit muscle GPb (rmGPb) was used as a model enzyme to study the reversible enzyme reaction. To follow both directions of this reversible reaction, we have developed a novel isothermal titration calorimetry (ITC) method for the determination of the direct reaction rate.

Cooperation of enzymes involved in carbohydrate digestion of Colorado potato beetle (, Say).

Colorado potato beetle (Leptinotarsa decemlineata, Say) is the main pest of Solanaceae and its survival is mainly dependent on the carbohydrate digestion. Characterizing the gut enzymes may help us with finding effective inhibitors for plant protection. Activity measurements revealed that gut extracts contain α- and β-glucosidase in addition to α-amylase.

Attack of Microcystis aeruginosa bloom on a Ceratophyllum submersum field: Ecotoxicological measurements in real environment with real microcystin exposure.

Overproduction of toxic cyanobacteria is a type of harmful algal blooms (HABs). The heptapeptide microcystins (MCs) are one of the most common cyanotoxins. There is increasing research concerning the effects of MCs on growth and physiology of vascular plants, however there is a lack of studies on their direct effects on aquatic macrophytes in the real environment.

Isolation of allithiamine from Hungarian red sweet pepper seed ().

A natural fat-soluble thiamine derivative, namely N-[(4-amino-2-methylpyrimidin-5-yl)methyl]-N-[(2E)-5-hydroxy-3-(prop-2-en-1-yldisulfanyl)pent-2-en-2-yl]formamide (allithiamine) has been identified only in garlic () until now. Hungarian red sweet pepper () was found as a new source of allithiamine. Extraction procedure and analytical method were developed for the isolation of allithiamine and a chemical synthesis of the compound was also developed.

Sour cherry extract inhibits human salivary α-amylase and growth of Streptococcus mutans (a pilot clinical study).

The purpose of this study was to determine whether cherry extract has any effect on salivary α-amylase activity (sAA) or on the level of Streptococcus mutans in human saliva. 70 patients (45 females and 25 males) in three age groups (22 children, 25 young adults, and 23 adults) were examined. All participants completed a questionnaire to obtain information on their oral health behaviour and life style.

The use of starch azure for measurement of alpha-amylase activity.

Despite being widely used, there is no standard protocol for α-amylase activity measurement with starch azure substrate. Boiling pre-treatment of starch azure suspension increased the reaction rate of hydrolysis catalysed by human salivary α-amylase (HSA) or porcine pancreatic α-amylase (PPA) and the sensitivity of spectrophotometric activity measurement has been improved. Kinetic constants, K, and v, obtained from parallel isothermal titration calorimetric (ITC) measurements on natural and starch azure revealed, that the blue starch derivative does not differ significantly from its natural counterpart from kinetic point of view.

HPLC method for measurement of human salivary α-amylase inhibition by aqueous plant extracts.

Control of hyperglycemia is an important treatment in metabolic disorders such as type II diabetes and obesity. α-Amylase, as the first enzyme of glucose release from dietary polysaccharides, is a potential target to identify new sources of novel anti-obesity and anti-diabetic drugs. In this work, different herbal extracts as α-amylase inhibitors were studied by measuring the rate of the cleavage of a maltooligomer substrate 2-chloro-4-nitrophenyl-β-D-maltoheptoside.

Optimization of desferrioxamine E production by Streptomyces parvulus.

Siderophores are produced by a number of microbes to capture iron with outstandingly high affinity, which property also generates biomedical and industrial interests. Desferrioxamine E (DFO-E) secreted by streptomycetes bacteria can be an ideal candidate for iron chelation therapy, which necessitates its cost-effective production for in vitro and animal studies. This study focused on the optimization of DFO-E production by Streptomyces parvulus CBS548.

α-Amylase Modulation: Discovery of Inhibitors Using a Multi-Pharmacophore Approach for Virtual Screening.

Better control of postprandial hyperglycemia can be achieved by delaying the absorption of glucose resulting from carbohydrate digestion. Because α-amylase initiates the hydrolysis of polysaccharides, the design of α-amylase inhibitors can lead to the development of new treatments for metabolic disorders such as type II diabetes and obesity. In this study, a rational computer-aided approach was developed to identify novel α-amylase inhibitors.

"Back to the Future": A New Look at Hydroxypropyl Beta-Cyclodextrins.

Since the discovery about 30 years ago (2-hydroxypropyl) beta-cyclodextrin, a highly soluble derivative of beta-cyclodextrin, has become an approved excipient of drug formulations included both in the United States and European Pharmacopoeias. It is recommended to use as solubilizer and stabilizer for oral and parenteral formulations. Recently, its pharmacological activity has been recognized in various diseases.

Simple ITC method for activity and inhibition studies on human salivary α-amylase.

Isothermal titration calorimetry (ITC) has an increasing significance in enzyme kinetic studies owing to its general applicability and sensitivity. In the present work, we aimed at developing a simple ITC-based screening procedure for the measurement of human salivary α-amylase (HSA) activity. Reaction of two substrates was studied with three independent methods (ITC, HPLC and spectrophotometry).

Anthocyanin composition, antioxidant efficiency, and α-amylase inhibitor activity of different Hungarian sour cherry varieties (Prunus cerasus L.).

Five Hungarian sour cherry cultivars were studied to determine their anthocyanin contents and their possible inhibitory properties. The water and methanol soluble antioxidant capacities were separately assessed by photoluminescence showing values ranged from 3.4μgmg(-1) to 15.

From carbohydrates to drug-like fragments: Rational development of novel α-amylase inhibitors.

Starch catabolism leading to high glucose level in blood is highly problematic in chronic metabolic diseases, such as type II diabetes and obesity. α-Amylase catalyzes the hydrolysis of starch, increasing blood sugar concentration. Its inhibition represents a promising therapeutic approach to control hyperglycaemia.

A comparative study of capillary electrophoresis and isothermal titration calorimetry for the determination of binding constant of human serum albumin to monoclonal antibody.

This paper focuses on the investigation of the interactions between the anti-HSA-mAb and its protein antigen using CZE, ACE, and isothermal titration calorimetry. The CZE revealed the formation of the anti-HSA-mAb·HSA and anti-HSA-mAb·(HSA)2 complexes and the binding constants determined by plotting the amount of the bound anti-HSA-mAb as a function of the concentration of HSA. The ACE provided information on the binding strength from the change in effective electrophoretic mobility of the anti-HSA-mAb.

Identification of protein phosphatase interacting proteins from normal and UVA-irradiated HaCaT cell lysates by surface plasmon resonance based binding technique using biotin-microcystin-LR as phosphatase capturing molecule.

Identification of the interacting proteins of protein phosphatases is crucial to understand the cellular roles of these enzymes. Microcystin-LR (MC-LR), a potent inhibitor of protein phosphatase-1 (PP1), -2A (PP2A), PP4, PP5 and PP6, was biotinylated, immobilized to streptavidin-coupled sensorchip surface and used in surface plasmon resonance (SPR) based binding experiments to isolate phosphatase binding proteins. Biotin-MC-LR captured PP1 catalytic subunit (PP1c) stably and the biotin-MC-LR-PP1c complex was able to further interact with the regulatory subunit (MYPT1) of myosin phosphatase.

Optimization of triacetylfusarinine C and ferricrocin productions in Aspergillus fumigatus.

Iron is an essential element for all microorganisms. Bacteria and fungi produce versatile siderophores for binding and storing this essential transition metal when its availability is limited in the environment. The aim of the study was to optimize the fermentation medium of Aspergillus fumigatus for siderophore production.