International Journal of Molecular Sciences

228 KiB

Open AccessArticle

Synthesis, Characterization, and Photovoltaic Properties of Soluble TiOPc Derivatives

by Young-Keun Kim, Hyo-Jin Kang, Young-Wook Jang, Su-Bin Lee, Seung-Min Lee, Ki-Suck Jung, Jin-Kook Lee and Mi-Ra Kim

Int. J. Mol. Sci. 2008, 9(12), 2745-2756; https://doi.org/10.3390/ijms9122745 - 19 Dec 2008

Cited by 12 | Viewed by 11462

Abstract

We have synthesized soluble TiOPc derivatives containing alkoxy groups for use as additives in dye-sensitized solar cells (DSSCs). The DSSC devices containing these TiOPc derivatives exhibited short-circuit current densities of 8.49~10.04 mA/cm² and power conversion efficiencies of 2.73~3.62 % under AM 1.5 [...] Read more.

We have synthesized soluble TiOPc derivatives containing alkoxy groups for use as additives in dye-sensitized solar cells (DSSCs). The DSSC devices containing these TiOPc derivatives exhibited short-circuit current densities of 8.49~10.04 mA/cm² and power conversion efficiencies of 2.73~3.62 % under AM 1.5 illumination and 100 mW/cm²irradiation. Full article

(This article belongs to the Special Issue Functional Colorants)

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277 KiB

Open AccessArticle

Vasorelaxant and Antioxidant Activities of Spilanthes acmella Murr.

by Orapin Wongsawatkul, Supaluk Prachayasittikul, Chartchalerm Isarankura-Na-Ayudhya, Jutamaad Satayavivad, Somsak Ruchirawat and Virapong Prachayasittikul

Int. J. Mol. Sci. 2008, 9(12), 2724-2744; https://doi.org/10.3390/ijms9122724 - 18 Dec 2008

Cited by 83 | Viewed by 15451

Abstract

This study reports the effect of Spilanthes acmella Murr. extracts on phenylephrine-induced contraction of rat thoracic aorta as well as their antioxidant activity. Results show that the extracts exert maximal vasorelaxations in a dose-dependent manner, but their effects are less than acetylcholine-induced nitric [...] Read more.

This study reports the effect of Spilanthes acmella Murr. extracts on phenylephrine-induced contraction of rat thoracic aorta as well as their antioxidant activity. Results show that the extracts exert maximal vasorelaxations in a dose-dependent manner, but their effects are less than acetylcholine-induced nitric oxide (NO) vasorelaxation. Significant reduction of vasorelaxations is observed in both N^G-nitro-L-arginine methyl ester (L-NAME) and indomethacin (INDO). In the presence of L-NAME plus INDO, synergistic effects are observed, leading to loss of vasorelaxation of both acetylcholine and the extracts. Similarly, the vasorelaxations of the extracts are completely abolished upon the removal of endothelial cells. This demonstrates that the extracts exhibit vasorelaxation via partially endothelium-induced NO and prostacyclin in a dose-dependent manner. Significantly, the ethyl acetate extract exerts immediate vasorelaxation (ED₅₀ 76.1 ng/mL) and is the most potent antioxidant (DPPH assay). The chloroform extract shows the highest vasorelaxation and antioxidation (SOD assay). These reveal a potential source of vasodilators and antioxidants. Full article

(This article belongs to the Section Biochemistry)

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1419 KiB

Open AccessReview

Large-scale Models Reveal the Two-component Mechanics of Striated Muscle

by Robert Jarosch

Int. J. Mol. Sci. 2008, 9(12), 2658-2723; https://doi.org/10.3390/ijms9122658 - 18 Dec 2008

Cited by 12 | Viewed by 15994

Abstract

This paper provides a comprehensive explanation of striated muscle mechanics and contraction on the basis of filament rotations. Helical proteins, particularly the coiled-coils of tropomyosin, myosin and α-actinin, shorten their H-bonds cooperatively and produce torque and filament rotations when the Coulombic net-charge repulsion [...] Read more.

This paper provides a comprehensive explanation of striated muscle mechanics and contraction on the basis of filament rotations. Helical proteins, particularly the coiled-coils of tropomyosin, myosin and α-actinin, shorten their H-bonds cooperatively and produce torque and filament rotations when the Coulombic net-charge repulsion of their highly charged side-chains is diminished by interaction with ions. The classical “two-component model” of active muscle differentiated a “contractile component” which stretches the “series elastic component” during force production. The contractile components are the helically shaped thin filaments of muscle that shorten the sarcomeres by clockwise drilling into the myosin cross-bridges with torque decrease (= force-deficit). Muscle stretch means drawing out the thin filament helices off the cross-bridges under passive counterclockwise rotation with torque increase (= stretch activation). Since each thin filament is anchored by four elastic α-actinin Z-filaments (provided with forceregulating sites for Ca²⁺ binding), the thin filament rotations change the torsional twist of the four Z-filaments as the “series elastic components”. Large scale models simulate the changes of structure and force in the Z-band by the different Z-filament twisting stages A, B, C, D, E, F and G. Stage D corresponds to the isometric state. The basic phenomena of muscle physiology, i. e. latency relaxation, Fenn-effect, the force-velocity relation, the length-tension relation, unexplained energy, shortening heat, the Huxley-Simmons phases, etc. are explained and interpreted with the help of the model experiments. Full article

(This article belongs to the Special Issue Muscle Contraction Mechanism, Motor Proteins Function and Molecular Aspects of Water)

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358 KiB

Open AccessArticle

Correlation of the Rates of Solvolysis of Two Arenesulfonyl Chlorides and of trans-β-Styrenesulfonyl Chloride — Precursors in the Development of New Pharmaceuticals

by Zoon Ha Ryu, Sang Wok Lee, Malcolm J. D’Souza, Lamia Yaakoubd, Samantha E. Feld and Dennis N. Kevill

Int. J. Mol. Sci. 2008, 9(12), 2639-2657; https://doi.org/10.3390/ijms9122639 - 17 Dec 2008

Cited by 12 | Viewed by 12671

Abstract

Additional specific rates of solvolysis have been determined, mainly in fluoroalcohol containing solvents, for benzenesulfonyl chloride (1) and p-nitrobenzenesulfonyl chloride (2). For trans-β-styrenesulfonyl chloride (3), a study has been carried out in 43 pure and binary solvents, covering a wide range of [...] Read more.

Additional specific rates of solvolysis have been determined, mainly in fluoroalcohol containing solvents, for benzenesulfonyl chloride (1) and p-nitrobenzenesulfonyl chloride (2). For trans-β-styrenesulfonyl chloride (3), a study has been carried out in 43 pure and binary solvents, covering a wide range of hyroxylic solvent systems. For the specific rates of solvolyses of each of the three substrates, a good correlation was obtained over the full range of solvents when the extended Grunwald-Winstein equation was applied. The sensitivities to changes in solvent nucleophilicity and solvent ionizing power are similar to values determined earlier and an S_N2 process is proposed. For 3, kinetic solvent isotope effects of 1.46 for k_H2O/k_D2O and 1.76 for k_MeOH/k_MeOD were determined. These are also compared to literature values for other sulfonyl chlorides. Full article

(This article belongs to the Special Issue Grunwald-Winstein Equations – 60 Years & Counting)

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458 KiB

Open AccessArticle

Potential Use of Quantum Dots in Flow Cytometry

by Raquel Ibáñez-Peral, Peter L. Bergquist, Malcolm R. Walter, Moreland Gibbs, Ewa M. Goldys and Belinda Ferrari

Int. J. Mol. Sci. 2008, 9(12), 2622-2638; https://doi.org/10.3390/ijms9122622 - 17 Dec 2008

Cited by 27 | Viewed by 14589

Abstract

QDs may offer significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We have examined the possible applications of QDs for flow cytometric measurements (FCM) by studying their excitation - emission spectra and their [...] Read more.

QDs may offer significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We have examined the possible applications of QDs for flow cytometric measurements (FCM) by studying their excitation - emission spectra and their binding to paramagnetic beads. We labelled beads with either QDs or a commonly-used fluorochrome (FITC) and studied their fluorescence intensity by FCM. Flow cytometric comparisons indicated that the minimum fluorophore concentration required for detection of QDs above autofluorescent background was 100-fold less than for FITC. Full article

(This article belongs to the Special Issue Quantum Dots: From Synthesis to Applications in Biomedicine and Life Sciences)

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183 KiB

Open AccessArticle

Occurrence of Aflatoxin M₁ in Dairy Products in Southern Italy

by Maria Teresa Montagna, Christian Napoli, Osvalda De Giglio, Roberta Iatta and Giovanna Barbuti

Int. J. Mol. Sci. 2008, 9(12), 2614-2621; https://doi.org/10.3390/ijms9122614 - 12 Dec 2008

Cited by 44 | Viewed by 12044

Abstract

A screening survey of the presence of aflatoxin M₁ (AFM₁) was carried out on 265 samples of cheese made from cow, buffalo, goat, sheep, sheep-goat milk collected in the Apulia region (Southern Italy). Selected samples included unripened, medium and long-term [...] Read more.

A screening survey of the presence of aflatoxin M₁ (AFM₁) was carried out on 265 samples of cheese made from cow, buffalo, goat, sheep, sheep-goat milk collected in the Apulia region (Southern Italy). Selected samples included unripened, medium and long-term ripened cheeses. AFM₁ was found in 16.6% of the analyzed samples. The highest positive incidence was for medium and long-term ripened cheeses, especially those made from sheep-goat milk, while buffalo cheeses tested consistently negative. Our results show that the level of contamination by AFM₁ in dairy products from Apulia Region are lower than in other Italian and European regions. Moreover, it is important to underline that a common European norm concerning the AFM₁ threshold limits for dairy products is still lacking. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

278 KiB

Open AccessArticle

Tobacco OPBP1 Enhances Salt Tolerance and Disease Resistance of Transgenic Rice

by Xujun Chen and Zejian Guo

Int. J. Mol. Sci. 2008, 9(12), 2601-2613; https://doi.org/10.3390/ijms9122601 - 11 Dec 2008

Cited by 54 | Viewed by 11704

Abstract

Osmotin promoter binding protein 1 (OPBP1), an AP2/ERF transcription factor of tobacco, has been demonstrated to function in disease resistance and salt tolerance in tobacco. To increase stress tolerant capability of rice, we generated rice plants with an OPBP1 overexpressing construct. Salinity shock [...] Read more.

Osmotin promoter binding protein 1 (OPBP1), an AP2/ERF transcription factor of tobacco, has been demonstrated to function in disease resistance and salt tolerance in tobacco. To increase stress tolerant capability of rice, we generated rice plants with an OPBP1 overexpressing construct. Salinity shock treatment with 250 mM NaCl indicated that most of the OPBP1 transgenic plants can survive, whereas the control seedlings cannot. Similar recovery was found by using the seedlings grown in 200 mM NaCl for two weeks. The OPBP1 transgenic and control plants were also studied for oxidative stress tolerance by treatment with paraquat, showing the transgenic lines were damaged less in comparison with the control plants. Further, the OPBP1 overexpression lines exhibited enhanced resistance to infections of Magnaporthe oryzae and Rhizoctonia solani pathogens. Gene expressing analysis showed increase in mRNA accumulation of several stress related genes. These results suggest that expression of OPBP1 gene increase the detoxification capability of rice. Full article

(This article belongs to the Special Issue Biotic and Abiotic Stress)

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184 KiB

Open AccessArticle

Analysis of Mechanisms of T-2 Toxin Toxicity Using Yeast DNA Microarrays

by Yumiko Iwahashi, Emiko Kitagawa and Hitoshi Iwahashi

Int. J. Mol. Sci. 2008, 9(12), 2585-2600; https://doi.org/10.3390/ijms9122585 - 11 Dec 2008

Cited by 14 | Viewed by 10476

Abstract

T-2 toxin is a mycotoxin that belongs to a group of type A tricothecenes found in agricultural products. The cytotoxicity of T-2 toxin was characterized by analysis of the yeast transcriptome upon challenge with T-2 toxin. Interestingly, T-2 toxin-induced yeast gene expression profiles [...] Read more.

T-2 toxin is a mycotoxin that belongs to a group of type A tricothecenes found in agricultural products. The cytotoxicity of T-2 toxin was characterized by analysis of the yeast transcriptome upon challenge with T-2 toxin. Interestingly, T-2 toxin-induced yeast gene expression profiles were found to be similar to profiles obtained following cycloheximide treatment. Moreover, T-2 toxin treatment was found to activate facilitators, gluconeogenesis and cell arrest related genes such as mitogen-activated protein kinase genes (FUS3). T-2 toxin attacks the membrane and as a result the membrane transport system was disturbed. A large number of genes are induced to restore the toxicity caused by T-2 toxin. However, the data did not suggest that DNA damage by alkylation (Mag1, a gene 3-methyl-adenine DNA glycosylase, 0.46-fold down regulated), no induction of DNA repair mechanisms such as recombination (RAD26, RAD52 and etc.) and excision repair (RAD7, RAD14, RAD16, RAD23 and etc.). These results suggested that the toxicity of the T-2 toxin was due to the disturbance of the cell membrane of the yeast cell and that T-2 toxin caused mild mutagenesis. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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169 KiB

Open AccessReview

Zearalenone and Reproductive Function in Farm Animals

by Fiorenza Minervini and Maria Elena Dell’Aquila

Int. J. Mol. Sci. 2008, 9(12), 2570-2584; https://doi.org/10.3390/ijms9122570 - 11 Dec 2008

Cited by 233 | Viewed by 18661

Abstract

Farm animals are exposed to zearalenone through the feed because of the widespread occurrence of this mycotoxin in cereals and clinical reproductive disorders due to mycotoxin effects are often reported in farm animal species. This review describes the metabolism, the mechanistic aspects, the [...] Read more.

Farm animals are exposed to zearalenone through the feed because of the widespread occurrence of this mycotoxin in cereals and clinical reproductive disorders due to mycotoxin effects are often reported in farm animal species. This review describes the metabolism, the mechanistic aspects, the clinical reproductive symptoms and the in vitro effects on functional parameters of oocytes and sperm cells induced by zearalenone and its derivatives in farm animals. The studies on in vitro effects allow to understand the action mechanisms of mycotoxins and, sometime, to explain the in vivo symptoms. The impairment of semen quality and female reproductive function induced by zearalenone could be a factor responsible for the reproductive failure in farm animals. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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1537 KiB

Open AccessArticle

Some Properties of Composite Panels Made from Wood Flour and Recycled Polyethylene

by Turgay Ozdemir and Fatih Mengeloglu

Int. J. Mol. Sci. 2008, 9(12), 2559-2569; https://doi.org/10.3390/ijms9122559 - 10 Dec 2008

Cited by 26 | Viewed by 10093

Abstract

This study investigated the effect of board type (unmodified vs. MAPE modified) on the surface quality and thickness swelling-water absorption properties of recycled high density polyethylene (HDPE) based wood plastic composites. Additionally, two commercially available coatings (cellulosic coating and polyurethane lacquer coating) were [...] Read more.

This study investigated the effect of board type (unmodified vs. MAPE modified) on the surface quality and thickness swelling-water absorption properties of recycled high density polyethylene (HDPE) based wood plastic composites. Additionally, two commercially available coatings (cellulosic coating and polyurethane lacquer coating) were also applied to composite surfaces and their adhesion strength, abrasion and scratch resistance, and gloss values were determined. This study showed that modification of the composites with MAPE coupling agent increased the surface smoothness and reduced the water absorption and thickness swelling of the panels. Abrasion resistance of the composites was also improved through MAPE modification. Regardless of board type, higher scratch resistance and gloss values were observed for polyurethane lacquer coated samples compared to those of cellulosic varnish coated ones. Improvement of adhesion strength was also seen on SEM micrographs. Full article

(This article belongs to the Section Biochemistry)

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209 KiB

Open AccessReview

Species-specific Fungal DNA in Airborne Dust as Surrogate for Occupational Mycotoxin Exposure?

by Anne Straumfors Halstensen

Int. J. Mol. Sci. 2008, 9(12), 2543-2558; https://doi.org/10.3390/ijms9122543 - 10 Dec 2008

Cited by 33 | Viewed by 13202

Abstract

Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR [...] Read more.

Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR detection of fungi with mycotoxin-producing potential seem to be a good surrogate for occupational exposure measurements that include all fungal structures independent of morphology and cultivability. Results should, however, be interpreted with caution due to variable correlations with mycotoxin concentrations. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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Open AccessReview

Protein Folding and Misfolding on Surfaces

by Massimo Stefani

Int. J. Mol. Sci. 2008, 9(12), 2515-2542; https://doi.org/10.3390/ijms9122515 - 10 Dec 2008

Cited by 64 | Viewed by 18054

Abstract

Protein folding, misfolding and aggregation, as well as the way misfolded and aggregated proteins affects cell viability are emerging as key themes in molecular and structural biology and in molecular medicine. Recent advances in the knowledge of the biophysical basis of protein folding [...] Read more.

Protein folding, misfolding and aggregation, as well as the way misfolded and aggregated proteins affects cell viability are emerging as key themes in molecular and structural biology and in molecular medicine. Recent advances in the knowledge of the biophysical basis of protein folding have led to propose the energy landscape theory which provides a consistent framework to better understand how a protein folds rapidly and efficiently to the compact, biologically active structure. The increased knowledge on protein folding has highlighted its strict relation to protein misfolding and aggregation, either process being in close competition with the other, both relying on the same physicochemical basis. The theory has also provided information to better understand the structural and environmental factors affecting protein folding resulting in protein misfolding and aggregation into ordered or disordered polymeric assemblies. Among these, particular importance is given to the effects of surfaces. The latter, in some cases make possible rapid and efficient protein folding but most often recruit proteins/peptides increasing their local concentration thus favouring misfolding and accelerating the rate of nucleation. It is also emerging that surfaces can modify the path of protein misfolding and aggregation generating oligomers and polymers structurally different from those arising in the bulk solution and endowed with different physical properties and cytotoxicities. Full article

(This article belongs to the Special Issue Protein Folding 2009)

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116 KiB

Open AccessArticle

A Nutritional Approach for the Management of Deoxynivalenol (DON) Toxicity in the Gastrointestinal Tract of Growing Chickens

by Wageha Awad, Khaled Ghareeb, Josef Böhm and Jürgen Zentek

Int. J. Mol. Sci. 2008, 9(12), 2505-2514; https://doi.org/10.3390/ijms9122505 - 8 Dec 2008

Cited by 6 | Viewed by 11147

Abstract

It has been shown that DON has negative effects on the active transport of some nutrients in the small intestine of chickens. The plausible interactions between food contaminants and natural components could be high. The present study investigated the effects of DON on [...] Read more.

It has been shown that DON has negative effects on the active transport of some nutrients in the small intestine of chickens. The plausible interactions between food contaminants and natural components could be high. The present study investigated the effects of DON on the presence or absence of dietary inulin on the electrophysiological response of the gut to glucose. Ussing chamber studies were conducted with isolated jejunal epithelia at the age of 35 days. Electrophysiology of the epithelia was recorded and the changes of the short-circuit current (Isc) were determined. The addition of Dglucose on the luminal side of the isolated mucosa increased (P < 0.05) the Isc in the control group and inulin supplemented group. The oligosaccharides did not increase glucose absorption in young healthy chickens compared with the controls. In the second experiment, after preincubation of tissues with DON, the addition of glucose did not increase the Isc in jejunum and colon in the control group (P > 0.05). However, in the dietary inulin supplemented group in both jejunum and colon, the addition of glucose after preincubation of tissues with DON increased the Isc, suggesting that the dietary inulin supplementation of the broilers regulated and improved the glucose absorption in the presence of DON and kept it at normal levels. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

117 KiB

Open AccessArticle

Development of a Generic PCR Detection of 3-Acetyldeoxynivalenol-, 15-Acetyldeoxynivalenol- and Nivalenol-Chemotypes of Fusarium graminearum Clade

by Jian-Hua Wang, He-Ping Li, Bo Qu, Jing-Bo Zhang, Tao Huang, Fang-Fang Chen and Yu-Cai Liao

Int. J. Mol. Sci. 2008, 9(12), 2495-2504; https://doi.org/10.3390/ijms9122495 - 5 Dec 2008

Cited by 62 | Viewed by 13222

Abstract

Fusarium graminearum clade pathogens cause Fusarium head blight (FHB) or scab of wheat and other small cereal grains, producing different kinds of trichothecene mycotoxins that are detrimental to human and domestic animals. Type B trichothecene mycotoxins such as deoxynivalenol, 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON) [...] Read more.

Fusarium graminearum clade pathogens cause Fusarium head blight (FHB) or scab of wheat and other small cereal grains, producing different kinds of trichothecene mycotoxins that are detrimental to human and domestic animals. Type B trichothecene mycotoxins such as deoxynivalenol, 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON) and nivalenol (NIV) are the principal Fusarium mycotoxins reported in China, as well as in other countries. A genomic polymerase chain reaction (PCR) to predict chemotypes was developed based on the structural gene sequences of Tri13 genes involved in trichothecene mycotoxin biosynthesis pathways. A single pair of primers derived from the Tri13 genes detected a 583 bp fragment from 15-AcDON-chemotypes, a 644 bp fragment from 3-AcDON-chemotypes and an 859 bp fragment from NIV-producing strains. Fusarium strains from China, Nepal, USA and Europe were identified by this method, revealing their mycotoxin chemotypes identical to that obtained by chemical analyses of HPLC or GC/MS and other PCR assays. The mycotoxin chemotype-specific fragments were amplified from a highly variable region located in Tri13 genes with three deletions for 15-AcDON-chemotypes, two deletions for 3-AcDON-chemotypes and no deletion for NIV-producers. This PCR assay generated a single amplicon and thus should be more reliable than other PCR-based assays that showed the absence or presence of a PCR fragment since these assays may generate false-negative results. The results with strains from several different countries as well as from different hosts further indicated that this method should be globally applicable. This is a rapid, reliable and cost-effective method for the identification of type B trichothecene mycotoxin chemotypes in Fusarium species and food safety controls. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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978 KiB

Open AccessReview

Mycotoxin Detection Plays “Cops and Robbers”: Cyclodextrin Chemosensors as Specialized Police?

by Pietro Cozzini, Gianluigi Ingletto, Ratna Singh and Chiara Dall’Asta

Int. J. Mol. Sci. 2008, 9(12), 2474-2494; https://doi.org/10.3390/ijms9122474 - 5 Dec 2008

Cited by 31 | Viewed by 12888

Abstract

As in a cops and robbers play we discover new mycotoxins and metabolites everyday and we are forced to develop new molecules quickly as chemo- or biosensors or to modify existing molecules able to recognize these new hazardous compounds. This will result in [...] Read more.

As in a cops and robbers play we discover new mycotoxins and metabolites everyday and we are forced to develop new molecules quickly as chemo- or biosensors or to modify existing molecules able to recognize these new hazardous compounds. This will result in an enormous cost saving to agro-food industry through the prevention and reduction of product recalls and reduced treatment costs. Here we present a brief review of the rapid methods used to detect mycotoxins, considering usefulness and limits. Then we propose a new fast, efficient and cheap methodology, based on a combination of computer chemistry aided design and fluorescence, that can help to drive synthesis in a more efficient way. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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Graphical abstract

256 KiB

Open AccessReview

Plant Products for Pharmacology: Application of Enzymes in Their Transformations

by Marie Zarevúcka and Zdeněk Wimmer

Int. J. Mol. Sci. 2008, 9(12), 2447-2473; https://doi.org/10.3390/ijms9122447 - 4 Dec 2008

Cited by 25 | Viewed by 15757

Abstract

Different plant products have been subjected to detailed investigations due to their increasing importance for improving human health. Plants are sources of many groups of natural products, of which large number of new compounds has already displayed their high impact in human medicine. [...] Read more.

Different plant products have been subjected to detailed investigations due to their increasing importance for improving human health. Plants are sources of many groups of natural products, of which large number of new compounds has already displayed their high impact in human medicine. This review deals with the natural products which may be found dissolved in lipid phase (phytosterols, vitamins etc.). Often subsequent convenient transformation of natural products may further improve the pharmacological properties of new potential medicaments based on natural products. To respect basic principles of sustainable and green procedures, enzymes are often employed as efficient natural catalysts in such plant product transformations. Transformations of lipids and other natural products under the conditions of enzyme catalysis show increasing importance in environmentally safe and sustainable production of pharmacologically important compounds. In this review, attention is focused on lipases, efficient and convenient biocatalysts for the enantio- and regioselective formation / hydrolysis of ester bond in a wide variety of both natural and unnatural substrates, including plant products, eg. plant oils and other natural lipid phase compounds. The application of enzymes for preparation of acylglycerols and transformation of other natural products provides big advantage in comparison with employing of conventional chemical methods: Increased selectivity, higher product purity and quality, energy conservation, elimination of heavy metal catalysts, and sustainability of the employed processes, which are catalyzed by enzymes. Two general procedures are used in the transformation of lipid-like natural products: (a) Hydrolysis/alcoholysis of triacylglycerols and (b) esterification of glycerol. The reactions can be performed under conventional conditions or in supercritical fluids/ionic liquids. Enzyme-catalyzed reactions in supercritical fluids combine the advantages of biocatalysts (substrate specificity under mild reaction conditions) and supercritical fluids (high mass-transfer rate, easy separation of reaction products from the solvent, environmental benefits based on excluding organic solvents from the production process). Full article

(This article belongs to the Section Green Chemistry)

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Open AccessReview

Discovery of Proteomic Code with mRNA Assisted Protein Folding

by Jan C. Biro

Int. J. Mol. Sci. 2008, 9(12), 2424-2446; https://doi.org/10.3390/ijms9122424 - 3 Dec 2008

Cited by 6 | Viewed by 11623

Abstract

The 3x redundancy of the Genetic Code is usually explained as a necessity to increase the mutation-resistance of the genetic information. However recent bioinformatical observations indicate that the redundant Genetic Code contains more biological information than previously known and which is additional to [...] Read more.

The 3x redundancy of the Genetic Code is usually explained as a necessity to increase the mutation-resistance of the genetic information. However recent bioinformatical observations indicate that the redundant Genetic Code contains more biological information than previously known and which is additional to the 64/20 definition of amino acids. It might define the physico-chemical and structural properties of amino acids, the codon boundaries, the amino acid co-locations (interactions) in the coded proteins and the free folding energy of mRNAs. This additional information, which seems to be necessary to determine the 3D structure of coding nucleic acids as well as the coded proteins, is known as the Proteomic Code and mRNA Assisted Protein Folding. Full article

(This article belongs to the Special Issue Protein Folding 2009)

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Open AccessArticle

QSAR Study of Antimicrobial 3-Hydroxypyridine-4-one and 3-Hydroxypyran-4-one Derivatives Using Different Chemometric Tools

by Razieh Sabet and Afshin Fassihi

Int. J. Mol. Sci. 2008, 9(12), 2407-2423; https://doi.org/10.3390/ijms9122407 - 2 Dec 2008

Cited by 25 | Viewed by 9265

Abstract

A series of 3-hydroxypyridine-4-one and 3-hydroxypyran-4-one derivatives were subjected to quantitative structure-antimicrobial activity relationships (QSAR) analysis. A collection of chemometrics methods, including factor analysis-based multiple linear regression (FA-MLR), principal component regression (PCR) and partial least squares combined with genetic algorithm for variable selection [...] Read more.

A series of 3-hydroxypyridine-4-one and 3-hydroxypyran-4-one derivatives were subjected to quantitative structure-antimicrobial activity relationships (QSAR) analysis. A collection of chemometrics methods, including factor analysis-based multiple linear regression (FA-MLR), principal component regression (PCR) and partial least squares combined with genetic algorithm for variable selection (GA-PLS) were employed to make connections between structural parameters and antimicrobial activity. The results revealed the significant role of topological parameters in the antimicrobial activity of the studied compounds against S. aureus and C. albicans. The most significant QSAR model, obtained by GA-PLS, could explain and predict 96% and 91% of variances in the pIC₅₀data (compounds tested against S. aureus) and predict 91% and 87% of variances in the pIC₅₀ data (compounds tested against C. albicans), respectively. Full article

(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)

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Open AccessArticle

Upregulation of Heme Oxygenase-1 Combined with Increased Adiponectin Lowers Blood Pressure in Diabetic Spontaneously Hypertensive Rats through a Reduction in Endothelial Cell Dysfunction, Apoptosis and Oxidative Stress

by Jian Cao, George Drummond, Kazuyoshi Inoue, Komal Sodhi, Xiao Ying Li and Shinji Omura

Int. J. Mol. Sci. 2008, 9(12), 2388-2406; https://doi.org/10.3390/ijms9122388 - 1 Dec 2008

Cited by 26 | Viewed by 10962

Abstract

This study was designed to investigate the effect of increased levels of HO-1 on hypertension exacerbated by diabetes. Diabetic spontaneously hypertensive rat (SHR) and WKY (control) animals were treated with streptozotocin (STZ) to induce diabetes and stannous chloride (SnCl2) to upregulate HO-1. Treatment [...] Read more.

This study was designed to investigate the effect of increased levels of HO-1 on hypertension exacerbated by diabetes. Diabetic spontaneously hypertensive rat (SHR) and WKY (control) animals were treated with streptozotocin (STZ) to induce diabetes and stannous chloride (SnCl2) to upregulate HO-1. Treatment with SnCl2 not only attenuated the increase of blood pressure (p<0.01), but also increased HO-1 protein content, HO activity and plasma adiponectin levels, decreased the levels of superoxide and 3-nitrotyrosine (NT), respectively. Reduction in oxidative stress resulted in the increased expression of Bcl-2 and AKT with a concomitant reduction in circulating endothelial cells (CEC) in the peripheral blood (p<0.005) and an improvement of femoral reactivity (response to acetylcholine). Thus induction of HO-1 accompanied with increased plasma adiponectin levels in diabetic hypertensive rats alters the phenotype through a reduction in oxidative stress, thereby permitting endothelial cells to maintain an anti-apoptotic environment and the restoration of endothelial responses thus preventing hypertension. Full article

(This article belongs to the Section Biochemistry)

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Open AccessArticle

Improving the Stability of Insulin in Solutions Containing Intestinal Proteases in Vitro

by Liefeng Zhang, Hui Jiang, Wenjie Zhu, Lin Wu, Lingling Song, Qiuyan Wu and Yong Ren

Int. J. Mol. Sci. 2008, 9(12), 2376-2387; https://doi.org/10.3390/ijms9122376 - 1 Dec 2008

Cited by 28 | Viewed by 9740

Abstract

Degradation of insulin was studied in this work. Casein and protamine could obviously suppress degradation of insulin by intestinal enzymes, and could protect insulin from degradation by the mechanism of competition and combination with proteolysis enzyme. What is more, co-incubated with HP-β-CD-casein or [...] Read more.

Degradation of insulin was studied in this work. Casein and protamine could obviously suppress degradation of insulin by intestinal enzymes, and could protect insulin from degradation by the mechanism of competition and combination with proteolysis enzyme. What is more, co-incubated with HP-β-CD-casein or HP-β-CD-protamine, most insulin was protected from degradation by intestinal enzymes. In addition, it was found that the complexation of insulin with HP-β-CD was characterized by UV absorption spectra. These results indicated that HP-β-CD, casein and protamine could offer some positive and useful results, and could protect insulin from degradation during their transit through the intestinal tract. Full article

(This article belongs to the Section Biochemistry)

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Open AccessArticle

Isolation and Identification of a Strain of Aspergillus Tubingensis With Deoxynivalenol Biotransformation Capability

by Chenghua He, Yanhong Fan, Guofang Liu and Haibin Zhang

Int. J. Mol. Sci. 2008, 9(12), 2366-2375; https://doi.org/10.3390/ijms9122366 - 27 Nov 2008

Cited by 70 | Viewed by 12590

Abstract

Deoxynivalenol (DON) is one of the most common contaminants of various foodstuffs. A biotransformation system was used in order to lessen the toxicity of DON. A strain of Aspergillus (NJA-1) was isolated from soil and cultured in an inorganic salt medium containing DON. [...] Read more.

Deoxynivalenol (DON) is one of the most common contaminants of various foodstuffs. A biotransformation system was used in order to lessen the toxicity of DON. A strain of Aspergillus (NJA-1) was isolated from soil and cultured in an inorganic salt medium containing DON. Bt2a/Bt2b primers were used to amplify the β-tubulin gene of NJA-1. Sequence analysis the PCR product and morphology observation indicated that NJA-1 belonged to Aspergillus tubingensis (aerobic fungi). The DNA sequence information of the PCR product was deposited in GenBank (accession number DQ9025790). The DNA sequence had 99% similarity to the Aspergillus tubingensis accession number AY820009. An unknown compound in NJA-1 showed the ability to convert DON into another product. The molecular weight of the bioconversion product was 18.1 D (H₂O) larger than that of DON. The analysis showed that DON could be hydrolyzed by NJA-1. The mean DON biotransformation rate was 94.4% after two weeks of cultivation. The finding presents a new method for DON biotransformation. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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Open AccessArticle

Growth and Mycotoxin Production by Chaetomium globosum Is Favored in a Neutral pH

by Matthew R. Fogle, David R. Douglas, Cynthia A. Jumper and David C. Straus

Int. J. Mol. Sci. 2008, 9(12), 2357-2365; https://doi.org/10.3390/ijms9122357 - 26 Nov 2008

Cited by 21 | Viewed by 13640

Abstract

Chaetomium globosum is frequently isolated in water-damaged buildings and produces two mycotoxins called chaetoglobosins A and C when cultured on building material. In this study, the influence of ambient pH on the growth of C. globosum was examined on an artificial medium. This [...] Read more.

Chaetomium globosum is frequently isolated in water-damaged buildings and produces two mycotoxins called chaetoglobosins A and C when cultured on building material. In this study, the influence of ambient pH on the growth of C. globosum was examined on an artificial medium. This fungus was capable of growth on potato dextrose agar ranging in pH from 4.3 to 9.4 with optimal growth and chaetoglobosin C production occurring at a neutral pH. In addition, our results show that sporulation is favored in an acidic environment. Full article

(This article belongs to the Special Issue Mycotoxins: Mechanisms of Toxicological Activity - Treatment and Prevention)

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Open AccessArticle

Recognition Properties and Competitive Assays of a Dual Dopamine/Serotonin Selective Molecularly Imprinted Polymer

by Roongnapa Suedee, Vatcharee Seechamnanturakit, Acharee Suksuwan and Bhutorn Canyuk

Int. J. Mol. Sci. 2008, 9(12), 2333-2356; https://doi.org/10.3390/ijms9122333 - 26 Nov 2008

Cited by 28 | Viewed by 12716

Abstract

A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the druginteraction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) [...] Read more.

A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the druginteraction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) as functional monomers, N,N′-methylene bisacrylamide (MBAA) as cross-linker, methanol/water mixture (4:1, v/v) as porogen and a mixture of dopamine (D) and serotonin (S) as templates. The prepared DS-MIP exhibited the greatest rebinding of the template(s) in aqueous methanol solution with decreased recognition in acetonitrile, water and methanol solvent. The binding affinity and binding capacity of DS-MIP with S were found to be higher than those of DS-MIP with D. The selectivity profiles of DS-MIP suggest that the D binding site of DS-MIP has sufficient integrity to discriminate between species of non-optimal functional group orientation, whilst the S binding site of DS-MIP is less selective toward species having structural features and functional group orientations different from S. The ligand binding activities of a series of ergot derivatives (ergocryptine, ergocornine, ergocristine, ergonovine, agroclavine, pergolide and terguride) have been studied with the DS-MIP using a competitive ligand binding assay protocol. The binding affinities of DSMIP were demonstrated in the micro- or submicro-molar range for a series of ergot derivatives, whereas the binding affinities were considerably greater to natural receptors derived from the rat hypothalamus. The DS-MIP afforded the same pattern of differentiation as the natural receptors, i.e. affinity for the clavines > lysergic acid derivatives > ergopeptines. The results suggest that the discrimination for the ergot derivatives by the dopamine and serotonin sites of DS-MIP is due to the structural features and functional orientation of the phenylethylamine and indolylethylamine entities at the binding sites, and the fidelity of the dopamine and serotonin imprinted cavities. Full article

(This article belongs to the Section Molecular Recognition)

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Open AccessArticle

Different Magnitudes of Tensile Strain Induce Human Osteoblasts Differentiation Associated with the Activation of ERK1/2 Phosphorylation

by Junfeng Zhu, Xiaoling Zhang, Chengtao Wang, Xiaochun Peng and Xianlong Zhang

Int. J. Mol. Sci. 2008, 9(12), 2322-2332; https://doi.org/10.3390/ijms9122322 - 26 Nov 2008

Cited by 20 | Viewed by 10490

Abstract

Mechanical factors are related to periprosthetic osseointegration following total hip arthroplasty. However, osteoblast response to strain in implanted femurs is unclear because of the absence of accurate stress-measuring methods. In our study, finite element analysis was performed to calculate strain distribution in implanted [...] Read more.

Mechanical factors are related to periprosthetic osseointegration following total hip arthroplasty. However, osteoblast response to strain in implanted femurs is unclear because of the absence of accurate stress-measuring methods. In our study, finite element analysis was performed to calculate strain distribution in implanted femurs. 0.8- 3.2% tensile strain was then applied to human osteoblasts. Higher magnitudes of strain enhanced the expression of osteocalcin, type I collagen, and Cbfa1/Runx2. Lower magnitudes significantly increased ALP activity. Among these, type I collagen expression increased with the activation of ERK1/2 phosphorylation in a strainmagnitude-dependent manner. Our study marks the first investigation of osteoblast response at different magnitudes of periprosthetic strain. The results indicate that the functional status of human osteoblasts is determined by strain magnitude. The strain distribution in the proximal region of implanted femur should be improved for osseointegration. Full article

(This article belongs to the Section Biochemistry)

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Int. J. Mol. Sci., Volume 9, Issue 12 (December 2008) – 24 articles , Pages 2322-2756

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