Volume 46, Issue No 1

Improvement of Xylanase Production by Cochliobolus sativus in Submerged Culture

Yasser Bakri, Mohammed Jawhar and Mohammed Imad Eddin Arabi*

Department of Molecular Biology and Biotechnology, AECS, P.O. Box 6091, SY-Damascus, Syria

Article history:
Received August 29, 2006
Accepted October 5, 2007

Key words:
xylanase, Cochliobolus sativus, waste utilization, submerged fermentation

Summary:
The xylanase production by a new Cochliobolus sativus Cs5 strain was improved under submerged fermentation. The xylanase was induced by xylan and repressed by glucose, sucrose, maltose, xylose, starch and cellulose. Highest enzyme production (98.25 IU/mL) was recorded when wheat straw (4 % by mass per volume) was used as a carbon source after 120 h of incubation. NaNO₃ increased xylanase production 5.4-fold as compared to the control. Optimum initial pH was found to be 4.5 to 5. The C. sativus Cs5 strain grown under submerged culture in a simple medium proved to be a promising microorganism for xylanase production.

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Food Peptidomics

Piotr Minkiewicz, Jerzy Dziuba*, Małgorzata Darewicz, Anna Iwaniak, Marta Dziuba and Dorota Nałęcz

University of Warmia and Mazury in Olsztyn, Chair of Food Biochemistry, Plac Cieszyński 1, PL-10-726 Olsztyn-Kortowo, Poland

Article history:
Received February 2, 2007
Accepted October 1, 2007

Key words:
food, biologically active peptides, peptidomics, functional properties, bioinformatics, proteolysis

Summary:
The aim of this review is to discuss the definition of food peptidomics and highlight the role of this approach in food and nutrition sciences. Similar to living organisms, food peptidome may be defined as the whole peptide pool present in a food product or raw material. This definition also covers peptides obtained during technological processes and/or storage. The area of interest of food peptidomics covers research concerning the origin of peptidome, its dynamic changes during processing and/or storage, the influence of its presence, the composition and changes in the pool of peptides on the properties of food products or raw materials as well as the methods applied in research into this group of compounds. The area of interests of food peptidomics would include biological activity, functional properties, allergenicity, sensory properties and information on the product or resource authenticity and origin as well as its history and relationships. Research methods applied in food peptidomics, with special emphasis on computational methods, are also summarized.

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Preparing Apigenin from Leaves of Adinandra nitida

Benguo Liu*, Zhengxiang Ning, Jianhua Gao and Keyong Xu

College of Light Industry and Food Science, South China University of Technology, Guangzhou, Guangdong, CN-510640, PR China

Article history:
Received February 17, 2006
Accepted July 6, 2006

Key words:
Adinandra nitida, flavonoid, apigenin, electrospray ionization mass spectrometry

Summary:
Leaves of Adinandra nitida were used as raw material, and a new industrially significant method of preparing apigenin was established by hydrolyzing a water extract and recrystallizing it with ethanol in order to obtain a new source for the production of this flavone. A yield of about 2.5 % (dry mass) was obtained with the purity of 93.05 %, determined by high performance liquid chromatography (HPLC). Moreover, the main flavonoids in leaves of Adinandra nitida and the product after acid hydrolysis were identified as camellianin A and apigenin, respectively, by ultraviolet-visible spectrometry (UV/VIS) and electrospray ionization mass spectrometry (ESI-MS).

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Antibiotic Resistance Mechanisms in Bacteria: Biochemical and Genetic Aspects

Senka Džidić¹, Jagoda Šušković²* and Blaženka Kos²¹Ruđer Bošković Institute, Department of Molecular Genetics, POB 180, HR-10 002 Zagreb, Croatia
²Laboratory for Antibiotic, Enzyme, Probiotic and Starter Culture Technology, Faculty of Food Technology and Biotechnology, University of Zagreb, POB 625, HR-10 001 Zagreb, Croatia

Article history:
Received June 5, 2007
Accepted November 19, 2007

Key words:
antibiotic resistance, multidrug resistance, antibiotic inactivation, target modification, drug efflux, membrane permeability changes, hypermutators, horizontal gene transfer

Summary:
Since the discovery and subsequent widespread use of antibiotics, a variety of bacterial species of human and animal origin have developed numerous mechanisms that render bacteria resistant to some, and in certain cases to nearly all antibiotics. There are many important pathogens that are resistant to multiple antibiotic classes, and infections caused by multidrug resistant (MDR) organisms are limiting treatment options and compromising effective therapy. So the emergence of antibiotic-resistant pathogens in bacterial populations is a relevant field of study in molecular and evolutionary biology, and in medical practice. There are two main aspects to the biology of antimicrobial resistance. One is concerned with the development, acquisition and spread of the resistance gene itself. The other is the specific biochemical mechanism conveyed by this resistance gene. In this review we present some recent data on molecular mechanisms of antibiotic resistance.

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