• KSTLE International Journal
• /
• v.6 no.1
• /
• pp.8-12
• /
• 2005

The electrorheological properties pertaining to the electrorheological (ER) bebaviour of chitin and chitosan suspensions in silicone oil were investigated. Chitosan suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field, while chitin suspension acted as a Newtonian fluid. The difference in behaior results from the difference in the conductivity of the chitin and chitosan particles, even though they have a similar chemical structure. The shear stress for the chitosan suspension exhibited a linear dependence on the volume fraction of particles and a 1.18 power of the electric field. The experimental results for the chitosan suspension correlated with the conduction model for ER response.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.14 no.2
• /
• pp.192-201
• /
• 1985

Two experiments, utilizing 204 broiler chicks of the Maniker strain, were conducted to study the effects of dried whey and chitin on the growth of chicks. In the first experiment, diets containing 5%, 10%, or 15% dried whey, or a control diet with no whey, were fed to chicks from 1 day to 4 weeks of age. There were no significant differences among the dietary groups, with respect to the rate of growth or protein or feed efficiency. In the second experiment, chicks were fed with diets containing no whey, 2% chitin, 20% dried whey, or 20% dried whey plus 2% chitin, from 1 day to 4 weeks of age. Adverse effects (diarrhea, crooked toes and enlarged cecum) were observed in the group fed 20% dried whey. The protein efficiency ratio (PER) and feed efficiency ratio (FER) tended to improve in the dietary groups with dried whey, as compared to the control group. No significant differences were observed in the total carcass nitrogen and lipid levels of dietary groups. But the chitin-supplemented diets tended to improve on the growth rate compared to the groups without chitin. The results of the two experiments suggest that the growing broiler chick can tolerate up to 15% dried whey in the diet, without any harmful effect on growth. Also, chitin may improve the poorer growth rate of chicks fed dried whey, but not all of the adverse effects of whey.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.6
• /
• pp.943-949
• /
• 2002

It has been proposed that chitin synthase 3 (CHS3)-nediated chitin synthesis during the vegetative cell cycle is regulated by chitin synthase 4 (CHS4) of Saccharomyces cerevisiae. To investigate direct protein-protein interaction between the coding products of these two genes, a domain of Chs3p that is responsible for interaction with Chs4p was identified, using the yeast two-hybrid system. This domain of 54 amino acids, termed MIRC3-4 (Maximum Interacting Region of Chs3p with Chs4p), is well conserved among CHS3 homologs of various fungi. Some mutations in MIRC3-4 resulted in a decrease in the enzymatic activity and chitin contents. Chs3p carrying those mutations exhibited weak interactions with Chs4p, when assayed by the yeast two-hybrid system. Surprisingly, all the mutants were sensitive to Calcofluor regardless of changes in enzymatic activities or chitin contents. This report deals with a core region in MIRC3-4 that affects the interaction with Chs4p.

• Korean Journal of Food Science and Technology
• /
• v.26 no.6
• /
• pp.787-790
• /
• 1994

An effective process manufacturing the decolorized chitin with high quality was established using shrimp shell powder. Ash and protein in shrimp shell powder were efficiently removed by 1.66% HCl and 3% NaOH treatments, respectively. A bleached chitin could be also obtained by 0.16% NaClO for 30 minutes, the treatment of which was much better than previously reported decolorization methods such as ethanol, acetone and $H_2O_2$ treatments. Since the pattern of IR spectrum of sample chitin was closely similar to those of commercially available chitins and the degree of deacetylation showed low value of 22.8%, it could be concluded that the bleached chitin obtained had highly-purified character as well as high quality of appearance.

• Analytical Science and Technology
• /
• v.15 no.2
• /
• pp.163-171
• /
• 2002

The adsorption characteristics of Cd(II) and Pb(II) ions has been studied by using chitin as an adsorbent. The pure chitin was obtained from the extraction of red-crab shell dumped by fish factory. Adsorption kinetics of Cd(II) and Pb(II) ions on the chitin reached at the maximum adsorption within two minutes. Adsorbed amounts of heavy metals were pH 7.0>10.5>3.5 in the following order. Adsorption ratio by chitin was 21${\sim}$99% for Cd(II) ion and 24${\sim}$95% for Pb(II) ion. Recovery ratio of Cd(II) ion on the chitin was 22${\sim}$53%, and that of Pb(II) ion was 22${\sim}$73%. The adsorption behavior of these heavy metals was explained well by Freundlich adsorption isotherm.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.110.3-111
• /
• 2003

The effect of biological control on the severity of hot pepper wilt disease was evaluated in the vinyl house with plants cultivated in the nursery soil containing chitin and chitinolytic microorganisms. The chitinolytic microorganisms, Trichoderma harzianum and Chromobacterium sp. strain C-61, were well survived in the nursery soil containing chitin. The hot pepper damping-off was markedly suppressed in the nursery soil containing chitin and chitinolytic microorganisms. The survival of chitinolytic microorganisms and suppression of damping-off were superior as the amounts of chitin added to the nursery soil increased, but growth of hot pepper was inhibited in the 10％ (w/w) chitin treatment. When the plants cultivated in the nursery soil containing 1％ chitin and chitinolytic microorganisms were transplanted in the vinyl house, the vegetative growth increased and the wilt disease was reduced as comparison with those of control.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.110.2-110
• /
• 2003

The effect of biological control on the severity of hot pepper wilt disease was evaluated in the vinyl house with plants cultivated in the nursery soil containing chitin and chitinolytic microorganisms. The chitinolytic microorganisms, Trichoderma harzianum and Chromobacterium sp. strain C-61, were well survived in the nursery soil containing chitin. The hot pepper damping-off was markedly suppressed in the nursery soil containing chitin and chitinolytic microorganisms. The survival of chitinolytic microorganisms and suppression of damping-off were superior as the amounts of chitin added to the nursery soil increased, but growth of hot pepper was inhibited in the 10％ (w/w) chitin treatment. When the plants cultivated in the nursery soil containing 1％ chitin and chitinolytic microorganisms were transplanted in the vinyl house, the vegetative growth increased and the wilt disease was reduced as comparison with those of control.

• Journal of Nutrition and Health
• /
• v.27 no.10
• /
• pp.996-1006
• /
• 1994

This study was performed to investigate the effect of dietary chitin & chitosan on cadmium (Cd) toxicity and lipid metabolism in rats. Forty-two male rats of Sprague-Dawley strain weighing 137$\pm$2g were blocked into 6 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400ppm in diet and chitin and chitosan were given at the level of 0 or 4%(w/w) of diet. The results are summarized as follow. Chitosan decreased the toxicity of Cd on liver, kidney and femur and increase the Cd content of fecal excretion. Chitosan increased the lipdi & cholesterol content of fecal excretion by combining with lipid and bile acid. Chitosan decreased lipid, cholesterol and TG content in serum and liver by combining with lipid and bile acid. Chitin was less effective than chitosan in decreasing of Cd toxicity and lipid content of rat.

• The Korean Journal of Malacology
• /
• v.13 no.1
• /
• pp.65-70
• /
• 1997

This strdy was performed to investigate the effect of chitin, chitosan and dithiocarbamate chitosan against cadmium accumulation. The Scapharca subcrenata were divided into four independent groups which were one control and three experimintal groups by camium alone treatmint or chitin, chitosan and dithsan and dithiocabamate chitosan which cadmium. Samples were analyzed by Varian 30/40 atomic absorption spectrophotometer. The results obtained were as follows;1. The cadmium concentration in water were isgnificantly decreased in three experimental group compared with that of control group (P<0.05)2. The cadmium concentration in muscle of S. srbcrenata in cadmium alone treatment group were similar to that of the chitin treatmint group, but chitosan and dithiocarbamate chitosan treatmint groups were significantly decreased (P<0.05)In conclusion, this study revealed the effect of chitin chitosan and dithiocarbamate chitosan against cadmium accumulation. It exhibited the highest effect at dithiocarbamate chitosan treatment group.

• YAKHAK HOEJI
• /
• v.43 no.4
• /
• pp.509-515
• /
• 1999

To search for new chitin biosynthesis inhibitors from natural sources, several higher plants were examined the inhibitory activity against chitin synthase IIby enzymatic assay. Among them, the extract of Schizandra chinensis strongly showed the inhibitory activity against chitin synthase II. Gomisin N and wuweizisu C were isolated from Schizandra chinensis and showed $IC_50$ value of $62.4{\;}\mu\textrm{g}/ml$ and $19.2{\;}\mu\textrm{g}/ml$, respectively. Activities of these compounds were more stronger than that of polyxin D. However, gomisin N and wuweizisu C showed weakly antifungal activities against various human pathogens.