Sevil Erdogan

Physicochemical comparison of chitin and chitosan obtained from larvae and adult Colorado potato beetle (Leptinotarsa decemlineata)

Chitins and chitosans obtained from larva and adult Colorado potato beetles (Leptinotarsa decemlineata) were physico-chemically characterized and differences between adults and larvae were identified. The dry weight chitin contents of the adult Colorado potato beetles and larvae were determined as 20% and 7%, respectively. The chitin produced chitosan yields of 72% from the adult Colorado potato beetles and 67% from the larvae. FTIR analysis showed that the isolated chitins were in the alpha form. Crystalline index values, determined by XRD, were 72% for larvae and 76% for adults. The degradation temperatures of the isolated chitin structures were measured by TGA, and this showed that the chitin from adult Colorado potato beetles had a more stable structure than that from the larvae. The surface morphologies of the isolated chitin and chitosan structures were analysed with SEM and it was revealed that these structures consisted of nanofibres. According to elemental analysis, the purity of chitin and chitosan from adults was greater than that from the larvae. The results of molecular analysis showed that the chitosans from adults (2.722 kDa) and larvae (2.676 kDa) of the Colorado potato beetle have low molecular weights. Antimicrobial and antioxidant activities of both adult and larval chitosans were determined. The adult potato beetle is more appropriate than the larvae as an alternative chitin source because of the fact that its dry weight chitin content, chitosan yield and purity of chitin are higher than those from the larvae, and its antimicrobial and antioxidant activities are also higher than those from the larvae.

A physicochemical characterization of fully acetylated chitin structure isolated from two spider species: With new surface morphology

Spiders are a huge group which includes more than 44,000 species. But there has been no study of the chitin structure of spiders. In this study we physicochemically characterized chitin structure of two common spider species (Geolycosa vultuosa and Hogna radiata). Chitin content was determined as 8-8.5% for G. vultuosa and 6.5-7% for H. radiata. FTIR, TGA and XRD results showed that the chitin structures are in α-form. Environmental scanning electron microscopy (ESEM) revealed that the surface morphology of each species is different. Chitin yielded from G. vultuosa has two different pore structures. The type one pore is rarely sequenced and its size ranges between 190 and 240 nm, while the type two pore is tightly sequenced and its size ranges between 11 and 32 nm. There is no information in previous studies about the chitin structure with two different pore morphologies. A new chitin surface morphology has been determined in G. vultuosa. The chitin isolated from H. radiata, has classic morphology: nanofibre structures (10-17 nm) and 195-260 nm sized pores. Acetylation degree of the chitin samples was calculated as 97% for G. vultuosa and 99% for H. radiata in accordance with elemental analysis results.

Chitin extraction and characterization from Daphnia magna resting eggs.

New application areas for chitin and its derivatives have been extensively investigated and there is a solid, growing demand for new chitin sources. In this present study, chitin content of Daphnia magna resting egg (18-21%) was determined for the first time. FTIR, elemental analysis, TGA, XRD and SEM studies revealed the structural and thermal properties of extracted α-chitin. This study suggests that D. magna resting eggs can be exploited as an attractive alternative chitin source.

Comparison of chitin structures isolated from seven Orthoptera species.

Differences in the physichochemical properties of the chitin structure of the exoskeleton of seven species from four genera were investigated in this study. The same method was used to isolate the chitin structure of the seven species. The physicochemical properties of the isolated chitins were revealed by ESEM, FTIR, TGA and XRD analyses. The FTIR, TGA and XRD results from the chitin samples were similar. The surface morphologies of the chitins were investigated by ESEM and interesting results were noted. While the surface morphologies of the chitins isolated from two species within the same genus were quite different, the surface morphologies of chitins isolated from species belonging to different genera showed similarity. It was determined that the dry weight chitin contents of the grasshopper species varied between 5.3% and 8.9%. The results of molecular analysis showed that the chitins from seven Orthoptera species (between 5.2 and 6.8 kDa) have low molecular weights. Considering that these invasive and harmful species are killed with insecticides and go to waste in large amounts, this study suggests that they should be collected and evaluated as an alternative chitin source.

High similarity in physicochemical properties of chitin and chitosan from nymphs and adults of a grasshopper.

This is the first study to explain the differences in the physicochemical properties of chitin and chitosan obtained from the nymphs and adults of Dociostaurus maroccanus using the same method. Fourier transform infrared spectroscopy, thermogravimetric analysis and x-ray diffraction analysis results demonstrated that the chitins from both the adults and nymphs were in the α-form. The chitin contents of the adults (14%) and nymphs (12%) were of the same order of magnitude. The crystalline index values of chitins from the adult and nymph grasshoppers were 71% and 74%, respectively. Thermal stabilities of the chitins and chitosans from adult and nymph grasshoppers were close to each other. Both the adult (7.2kDa) and nymph (5.6kDa) chitosans had low molar masses. Environmental scanning electron microscopy revealed that the surface morphologies of both chitins consisted of nanofibers and nanopores together, and they were very similar to each other. Consequently, it was determined that the physicochemical properties of the chitins and chitosans from adults and nymphs of D. maroccanus were not very different, so it can be hypothesized that the development of the chitin structure in the nymph has almost been completed and the nymph chitin has the same characteristics as the adult.

Characterisation of α-chitin extracted from a lichenised fungus species Xanthoria parietina

Lichens are symbiotic associations formed mainly by ascomycete fungi and green algae or cyanobacteria. The presence of chitin in the fungal cell wall has been revealed by previous studies. Considering the presence of fungi in the lichens, this work determines the presence of chitin in a cosmopolitan lichen species Xanthoria parietina. In this study, chitin was derived from a lichen species for the first time and its physicochemical properties were determined by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and elemental analysis. The dry weight chitin content of X. parietina was 4.23%, and this chitin was in the α-form. The crystalline index value of the lichen chitin was calculated as 70.1%. The chitin from X. parietina had a smooth surface.

Characteristics of corneal lens chitin in dragonfly compound eyes

Chitin in the compound eyes of arthropods serves as a part of the visual system. The quality of chitin in such highly specialised body parts deserves more detailed examination. Chitin in the corneal (ommatidial) lenses of dragonfly (Sympetrum fonscolombii) compound eyes was isolated by using the classical chemical method. The chitin content of the corneal lenses was determined to be quite high (20.3±0.85%). The FT-IR analysis showed that corneal lens chitin was in the α-form as found in all arthropod species where mechanical strength is required. The surface morphology analysis by scanning electron microscopy revealed that the outer part of corneal lenses consisted of long chitin fibrils with regular arrays of papillary structures while the smoother inner part had concentric lamellated chitin formation with shorter chitin nanofibrils. Chitinase enzymatic digestion studies, elemental analysis results and the degree of acetylation value showed the purity of chitin samples from corneal lens. The maximum degradation temperature value of the corneal lens chitin was observed at 369.2°C. X-ray analysis revealed that corneal lens chitin has high crystallinity index; 96.4%. Identification of chitin found in ommaditia of insect compound eyes can provide insights into insect vision and chitin-based optical material design studies.

he Biodiversity of Bdelloid Rotifers on a Single Rock Affected by Cardinal Directions

Notwithstanding that there are ongoing studies being carried out on various groups of microorganisms for determining diversity pattern of microorganisms (smaller than 2 mm), they mostly focus on bacteria. Bdelloid rotifers are another group of microorganisms sized between 77-1500 μm. In this study, we investigated whether different cardinal directions which affect temperature and humidity of rocks have an effect on bdelloid diversity or not by examining bdelloid rotifers living on 10 cm 2 of lichen samples which was collected from the west, east, north sides and from top of a rock covered with Lecanora muralis (lichen). The results showed that species richness, species composition and abundance of bdelloid rotifers are affected by different cardinal directions. KeywordsSpecies Richness; Abundance; Diversity Pattern; Microorganism

GENDER INFLUENCES DIFFERENTIATION OF CHITIN AMONG BODY PARTS.

Earlier reports have established that chitin isolates from each body part of an insect cuticle can exhibit diverse physicochemical properties. But it is still unknown if the gender of the insect can influence characteristics of chitin isolates from different body parts. The present study addresses this question. As a result, important physicochemical differences in the chitin samples from different body parts of Melolontha sp. were recorded on the basis of sex. The chitin samples were extracted from eight different body parts (antennae, head, eyes, thorax, abdomen, elytra, hindwings, and legs) of female and male. The most remarkable variations in the chitin isolates from female and male body parts were recorded in chitin content, crystallinity, thermal stability, and surface morphology. And also it was wondered these chitin isolates from different body parts of female and male could find different applications. To check this hypothesis, the chitin samples from female and male were interacted with bovine serum albumin (BSA) protein and important variations were observed.