Volume 38 Issue 1

January 2010


Dear readers of the Hacettepe Journal of Biology and Chemistry,

As I begin my fourth year as a Chief Editor of Hacettepe Journal of Biology and Chemistry, it is a great pleasure to greet our readers in this journal once again and to update you on what has happened in three years. 

Magnetic Affinity Separation of Recombinant Fusion Proteins

Isolation and separation of proteins is an important procedure in all areas of biosciences and biotechnology. Currently recombinant fusion proteins are produced routinely; in order to simplify their isolation from complex samples, magnetic separation techniques can be efficiently used. This short review paper shows examples of the most important fusion affinity tags and commercially available magnetic affinity and ion exchange particles enabling efficient capture of recombinant fusion proteins. A list of realized isolation procedures documents the efficiency of magnetic separation techniques. 

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Synthesis and Characterization of the Poly(ethylene glycol) Grafted Unsaturated Microbial Polyesters

Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3- hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxy- octanoate-co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by 1H NMR and FTIR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). 

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Preparation and Properties of Electrospun Poly(vinyl alcohol) Blended Hybrid Polymer with Aloe vera and HPMC as Wound Dressing

A series of poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP)/poly(ethylene glycol) (PEG) hybrid nanofibers were fabricated by an electrospinning method, in order to be used as a potential wound dressing material. The effect of Aloe vera was investigated in terms of solution properties such as viscosity, conductivity, pH and surface tension. The nanofibrous wound dressing materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). SEM results revealed that the fiber diameters ranged between 200-500 nm and they were linear, homogenous and free of beads. DSC thermograms indicated that the addition of Aloe vera affects the crystal structure and efficiently cross-links the hybrid polymer, forming an amorphous structure with a melting temperature (Tm) of 219oC at an Aloe vera concentration of 3%. FTIR results clearly resolved the hybrid polymer structure of nanofibers obtained. 

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Selective Preconcentration of Fe3+ Using Ion-Imprinted Thermosensitive Particles

Molecular imprinting is a form of template polymerization which has been used to produce artificial binding sites in porous polymer particles that exhibit selective rebinding of the imprint or template molecules used in the fabrication. In this study, thermosensitive ion- imprinted polymers (TIIP) were prepared for selective preconcentration of Fe3+ ions. Langmuir and Freundlich adsorption models for TIIP were applied to describe the experimental isotherm and isotherm constants. Equilibrium data fit very well to the Langmuir model in the entire concentration range (5-40 mg/L). Furthermore, the selective adsorption of Fe3+ ions was confirmed by comparing the adsorption amount of other metal ions, Al3+, Zn2+, Co2+, Cu2+ and Mn2+

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An Approach for Trophic Gradient in Lake Mogan (Turkey): A Shallow Eutrophic Lake

Lakes become more productive as they accumulate nutrients with time and this process is called natural eutrophication which probably occurs very rarely. This natural eutrophication is generally fastened by antropogenic factors. Lake Mogan is a shallow lake with surface area 5.5 km2 in the close vicinity of Ankara, Turkey. Lake is under the recreational use. Natural process of eutrophication gained a momentum due to anthropogenic effects in the last decade. Numerous studies and suggestions have been made as well as prevention, but process is continuing as represented in this study. Lake eutrophication assessment was done in order to illustrate trophic gradient changes and its impact on zooplankton and zoobenthos. Trophic state index (TSI) which consists three parameters; total phosphorus (orthophosphate), chlorophyll-a concentration and Secchi disc depth, is constructed. No possible trophic gradient change was observed in lake spatially but changes according to seasons are evaluated. 

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Taxonomy of Symphytum asperum Lepechin and S. sylvaticum Boiss. (Boraginaceae) based on Macro- and Micro-morphology

Symphytum asperum Lepechin and S. sylvaticum Boiss. species are taxonomically very difficult to solve. Many taxonomical arrangements were done by different researchers before with observing herbarium sheets. In our research 25 populations were observed in field and we reached the decision that both of these species’ infraspecific taxa should be synonymized because of the continuation of the characters used to distinguish taxa before. S. asperum Lepechin var. armeniacum (Bucknall) Kurtto proposed by Kurtto was synonymed and included in S. asperum Lepechin. S. sylvaticum Boiss subsp. sepulcrale var. sepulcrale and S. sylvaticum Boiss subsp. sepulcrale (Boiss.&Bal.) Greuter&Burdet var. hordokopii (Kurtto) R.Mill. were synonymed and included to S. sylvaticum. The reasons of these taxonomical rearrangements were gathered from field observations, morphological measurements and scanning electron microscope images. 

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Ethnobotanical Properties of Akçakoca District in Düzce (Turkey)

Turkey has a rich flora because of its geographical and climatic properties so traditional names and uses of plants as medicine, food and for the other aims have improved in Anatolia. Some Turkish local plant names and their uses were collected during the floristic excursions about Akçakoca’s flora from 2000 to 2003. In Akçakoca, 46 taxa have 48 Turkish local names and all of them are used for various purposes by local people. 21 of them are traditional medicine for human treatments, 19 are edible green or cooked and 4 are fuel. 19 usages are firstly recorded in this study. 

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Physical and Chemical Properties of the Soils at Burned and Unburned Pinus brutia Ten. Forest Sites in the Marmaris Region, Turkey

The aim of this study was to determine the long-term post-fire changes to the physical and chemical properties of the soil in Pinus brutia Ten. forests found on ophiolitic rocks in the Marmaris region, southwestern Turkey. Six sites that had burned at different times (3, 6, 8, 9, 16, 26 years ago) and two sites that had not burned for a long time (at least 50 and 100 years) were selected. Three plots 1 ha in size were randomly selected within each site, and three soil samples were collected from randomly selected points within each plot. Soil texture, pH, CaCO3 content, organic matter content, electrical conductivity, and exchangeable cation concentrations of the soil samples were determined. Soil texture did not vary among the study sites, and percentages of sand, silt, and clay did not differ significantly among the study sites. Organic matter content was significantly higher at unburned sites, but was similar at all the burned sites. There was no significant difference between the three-year-old site and the other sites in terms of exchangeable cation concentrations, electrical conductivity, pH, or amount of CaCO3. Although there were some slight trends with time since the fire for some of the variables evaluated, soil properties did not change drastically with time, or at least changed without a trend among the study sites. This was attributed both to the importance of studying early post-fire years to detect a change in soil properties, and of site heterogeneity. 

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