• The Plant Pathology Journal
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• v.33 no.6
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• pp.597-601
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• 2017

The clpks18 gene was first cloned and identified in Curvularia lunata. It contains 6571 base pairs (bp) and an 6276 bp open reading frame encoding 2091 amino acids. The ClPKS18 deletion mutant displayed an albino phenotype, and almost lost the ability to product 5-(hydroxymethyl) furan-2-carboxylate (M5HF2C) toxin, implying that clpks18 gene in C. lunata is not only involved in 1,8-dihydroxynaphthalene melanin synthesis, but also relatively associated with M5HF2C toxin biosynthesis of the pathogen. The pathogenicity assays revealed that ${\Delta}ClPKS18$ was impaired in colonizing the maize leaves, which corresponds to the finding that ClPKS18 controls the production of melanin and M5HF2C in C. lunata. Results indicate that ClPKS18 plays a vital role in regulating pathogenicity of in C. lunata.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.23 no.2
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• pp.93-98
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• 2012

Botulinum toxins are the most potent toxins known to mankind. Botulinum toxin acts by blocking the cholinergic neuromuscular or the cholinergic autonomic innervation of exocrine glands and smooth muscles. Seven distinct antigenic botulinum toxins (A, B, C, D, E, F and G) produced by different strains of Clostridium botulinum have been described and only A and B type of botulinum toxins were clinically used. Toxins were consisted of a heavy chain with a molecular weight of 100 kD and a light chain with a molecular weight of 50 kD. Toxins are bound with an astounding selectivity to glycoprotein structures located on the cholinergic nerve terminal. Subsequently light chain of toxin is internalized and cleaves different proteins of the acetylcholine transport protein cascade transporting the acetylcholine vesicle from the intracellular space into the synaptic cleft. After a decade of therapeutic application of the toxin, no anaphylaxis or deaths have been reported and systemic adverse effects have not been reported so far. However the toxin's immunologic properties can lead to the stimulation of antibody production, potentially rendering further treatments ineffective. Botulinum toxin is a safe and effective treatment. Use of botulinum toxin in clinical medicine has grown exponentially in recent years, and many parts of the human body are now being targeted for therapeutic purposes.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.693-699
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• 2016

Clostridium difficile toxin A is known to cause deacetylation of tubulin proteins, which blocks microtubule formation and triggers barrier dysfunction in the gut. Based on our previous finding that the Clostridium difficile toxin A-dependent activation of histone deacetylase 6 (HDAC-6) is responsible for tubulin deacetylation and subsequent microtubule disassembly, we herein examined the possible effect of potassium acetate (PA; whose acetyl group prevents the binding of tubulin to HDAC-6) as a competitive/false substrate. Our results revealed that PA inhibited toxin A-induced deacetylation of tubulin and recovered toxin A-induced microtubule disassembly. In addition, PA treatment significantly decreased the production of IL-6 (a marker of inflamed tissue) in the toxin A-induced mouse enteritis model. An in vitro HDAC assay revealed that PA directly inhibited HDAC-6-mediated tubulin deacetylation, indicating that PA acted as a false substrate for HDAC-6. These results collectively indicate that PA treatment inhibits HDAC-6, thereby reducing the cytotoxicity and inflammatory responses caused by C. difficile toxin A.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.866-873
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• 2022

Growth rate and production of the paralytic shellfish poisoning toxin (PST) of a toxic dinoflagellate Alexandrium pacificum (LIMS-PS-2611) isolated from the southern sea of Korea, were examined under various temperatures and salinity conditions. The maximum growth rate (0.28 day^-1) was observed under 25℃ and 30 psu. Optimal growth (≥ 70% of maximum growth rate) was obtained between 20~25℃ and 25~35 psu. Among the PSTs of A. pacificum, the principal toxins were C1+2 and GTX5 in N-sulfocarbamoyl toxin group, and minor components were characterized as neoSTXs in the carbamate toxin group. Maximum toxin content was observed under 20℃ and 30 psu, and the toxin content increased with the increase of salinity. Low toxin contents were measured under the temperature and salinity conditions of the maximum growth rate. Therefore, the PSP of bivalve, which occurs at a temperature range of 20-25℃ in June, might have been derived from A. pacificum.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.483-489
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• 1993

Bovine fibroblasts were cultured in Dulbecco's Modified Eagle's Medium and then treated with control, insulin (I, $1{\mu}g/ml$), cholera toxin (CT, 0.1-100 ng/ml) or CT (0.1-100 ng/ml) + I ($1{\mu}g/ml$). Cholera toxin, an activator of adenylate cyclase, significantly decreased insulin induced DNA synthesis (p<0.05). The modulation of DNA synthesis apparently involves events occurring in early stage of cell growth, at least between the first 4 and 8 hour of CT treatment. Insulin induced collagen as well as noncollagen synthesis in cell layer, however, these syntheses were reduced by addition of cholera toxin (p<0.05) but were not completely reduced. It is not clear whether the reduction of insulin-induced cell layer collagen or noncollagen proteins by CT is involved in the inhibitory effect on insulin-induced DNA synthesis. However, we could rule out the hypothesis that insulin-induced DNA synthesis is reduced by CT-induced cellular differentiation.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1051-1056
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• 2002

In vitro binding efficacy of esterified glucomannan (E-GM) (0.1%) on aflatoxin B1 (AF) (300 ppb), ochratoxin A (OA) (2 ppm) and T-2 toxin (T-2) (3 ppm), when present alone or in combination, was evaluated in toxin-contaminated feed at pH 4.5 and 6.5. Esterified glucomannan showed significantly (p<0.01) higher binding with AF (81.6%), whereas those recorded with T-2 (27.8%) and OA (25.6%) were moderate. Binding of each toxin decreased as the number of toxins in feed increased. pH of medium showed no effect on mycotoxin binding ability of E-GM. A $2{\times}2{\times}2{\times}2$ factorial experiment of 5 week duration was conducted to study the effects of two dietary levels each of AF (0 and 300 ppb), OA (0 and 2 ppm), T-2 (0 and 3 ppm ) and E-GM (0 and 0.1%) on the immune competence of a total of 960 day-old commercial broilers. Reductions in size of thymus (by AF and T-2) and bursa (by AF) and antibody titers against Newcastle disease and Infectious Bursal disease (by all the toxins) were noted. Additive and antagonistic interactions were seen among the toxins on certain parameters. Esterified glucomannan significantly (p<0.01) improved antibody titers and weights of bursa ofFabricius and thymus indicating its counteracting efficacy against immunosuppression in mycotoxicosis of multiple origin.

• BMB Reports
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• v.43 no.1
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• pp.23-28
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• 2010

Binary toxin consisting of BinA and BinB from Bacillus sphaericus is toxic to mosquito larvae. BinB is responsible for specific binding to the larval gut cell membrane while BinA is crucial for toxicity. To investigate functional role of cysteine in BinB, three cysteine residues at positions 67, 161, and 241 were replaced by alanine or serine. Mutations at these positions did not affect protein production and overall structure of BinB. These cysteine residues are not involved in disulfide bond formation between BinB molecules. Mosquito-larvicidal assays revealed that C67 and C161 are essential for toxicity, whereas C241 is not. Mutations at C67 and C161 resulted in weaker BinA-BinB interaction. The loss of toxicity may be due to the reduction of interactions between BinA and BinB or BinB and its receptor. C67 and C161 could also play a part during conformational changes or internalization of the binary toxin into the target cell.

• The Plant Pathology Journal
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• v.16 no.2
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• pp.90-97
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• 2000

No Abstract.See Full-text

• Proceedings of the Microbiological Society of Korea Conference
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• 1999.04a
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• pp.27-28
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• 1999

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.877-883
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• 2006

A feeding trial was conducted on commercial broilers for a period of 35 days to determine the individual and combined effects of aflatoxin (AF) and T-2 toxin (T-2) on performance, organ weights and immune status. The efficacy of dietary glucomannan-containing yeast product (GYP) ($Mycosorb^{(R)}$) and hydrated sodium calcium aluminosilicate (HSCAS) in preventing the adverse effects of aflatoxin and T-2 toxin was also evaluated. Twelve dietary treatments ($4{\times}3$ factorial) comprising two dietary levels each of AF (0 and 2 mg/kg), T-2 toxin (0 and 1 mg/kg), GYP (0 and 1 kg/ton) and HSCAS (0 and 10 kg/ton) were tested on 720 commercial broiler chickens divided at random into 36 replicates of 20 chicks each (10 males and 10 females). Weight gain and feed intake were recorded weekly. Organ morphology and antibody titers for Newcastle disease (ND) and infectious bursal disease (IBD) were measured on the $35^{th}$ day. AF and T-2 toxin individually decreased weight gain and increased feed conversion ratio (FCR) (p<0.05). AF alone (p<0.05) increased weights of liver, kidney, gizzard and spleen and reduced thymus and bursal weights. T-2 toxin (p<0.05) increased liver and gizzard weights and decreased thymus weight. Both AF and T-2 toxin when fed individually affected ND and IBD titers in a significant manner. Significant interactions between AF and T-2 toxin were observed for their additive effects on weight gain, FCR, organ weights and antibody titers. Addition of GYP (p<0.05) improved weight gain, feed conversion efficiency and restored the organ weights. Antibody titers against ND and IBD were significantly improved with the supplementation of GYP. Supplementation of HSCAS (p<0.05) resulted in improvement in weight gain and restored organ weights in the groups fed AF alone, but not in T-2 toxin fed groups. HSCAS inclusion did not influence FCR in toxin fed groups. Addition of HSCAS (p<0.05) improved the antibody titers against ND and IBD only in AF fed groups. Thus, the results indicate that addition of GYP is effective in averting the individual and combined toxicity of aflatoxin and T-2 toxin in commercial broilers, while HSCAS is effective only against aflatoxin.