Thiabendazole Research Articles

Effects of benzimidazole analogs on cultures of differentiating rodent embryonic cells

Micromass cell culture systems for rat embryo midbrain (CNS) and limb bud (LB) cells were employed to assess the in vitro developmental toxicity of the benzimidazole analogs, mebendazole (MBZ), thiabendazole (TBZ), and nocodazole (NCZ), in addition to the classic microtubule inhibitor, colchicine. Comparison was made to albendazole (ABZ), a previously studied benzimidazole anthelmintic. Two parameters for assessing developmental toxicity were measured: differentiation and cytotoxicity. The relative potencies of the benzimidazole analogs in the micromass system (NCZ > MBZ ∼ ABZ ⪢ TBZ) mirrored their effectiveness in an assay for in vitro inhibition of mammalian tubulin polymerization. Colchicine also exhibits a high affinity for mammalian tubulin and was a potent inhibitor of cell proliferation, chondrogenesis, and neuronal differentiation. Immunofluorescent staining of Day 1 LB cultures with a monoclonal antibody to β-tubulin revealed that these agents elicited mitotic arrest. Many anti-tubulin agents are teratogenic in rats and their in vivo developmental toxicity may reflect perturbation of microtubular structure or function. With the exception of TBZ, these agents should be considered potential developmental toxicants since they inhibit cell growth and differentiation of micromass cultures at nanomolar concentrations.

Fungi associated with banana crown rot on field-packed fruit from the Windward Islands and assessment of their sensitivity to the fungicides thiabendazole, prochloraz and imazalil

Crown rot of bananas causes serious losses in fruit exported to the UK from the Windward Islands (WI). A survey was undertaken to investigate whether the recent move to field packing, and the change from fungicide dipping to applying a fungicide-coated ‘crown pad’ directly to the crown, have affected the complex of fungal species that cause the disease. Isolations were made from rotted banana crowns from the WI over two years. In general, those fungi isolated were those previously reported to cause crown rot. The most common were Colletotrichum spp., Fusarium spp. and Botryodiplodia theobromae. The sensitivity of fungal isolates to the currently used fungicide, thiabendazole (TBZ) and also to imazalil and prochloraz was tested in vitro. Most of the fungi isolated showed expected levels of sensitivity to TBZ, but some isolates of Colletotrichum appear to have developed tolerance to this fungicide. In addition, fungi known to be relatively insensitive to TBZ, e.g. Nigrospora spp. and Penicillium spp., were isolated from diseased crowns at higher frequencies than expected. All the fungi tested, including those insensitive to TBZ, were sensitive to prochloraz and imazalil; these fungicides might therefore be considered as alternatives to TBZ for incorporation into crown pads.

Chronic Toxicity Test of o-Phenylphenol and Thiabendazole by Simultaneous Administration to Mice

o-Phenylphenol (OPP) and thiabendazole (TBZ), which are fungicides, have been approved as food additives in Japan. OPP induces urinary bladder tumor and renal lesions in rats but not in mice. TBZ has an enhancing effect on urinary bladder carcinogenesis induced by OPP in rats. The present study was performed to examine the combined effects of OPP and TBZ on mice. Groups of 20 male Crj: B6C3F1, mice were fed the basal diet (control, group C), diet containing 0.2% TBZ (group T), 0.65% OPP (group O-1), 1.3% OPP (group O-2), 2.6% OPP (group O-3), 0.65% OPP plus 0.2% TBZ (group OT-1), 1.3% OPP plus 0.2% TBZ (group OT-2) or 2.6% OPP plus 0.2% TBZ (group OT-3) for 52 weeks. The survival rates were 100% (20/20), 90% (18/20), 100% (20/20), 95% (19/20), 100% (20/20), 90% (18/20), 75% (15/20) and 70% (14/20) in group C, T, O-1, O-2, O-3, OT-1, OT-2 and OT-3, respectively. The treated groups suffered growth retardation throughout the study. The kidney weights showed a dose-related decrease in the O and OT groups. No treatment-related increase in tumor formation of any organ or tissue was observed. Dose-related increases were observed in the incidences of degenerative and necrotic changes in tubular epithelium and transitional cells of the kidney, and of anisonucleosis and pigmentation in liver cells in the O and OT groups. Under the experimental conditions employed, OPP plus TBZ induced no urinary bladder tumor in mice.

Curing to prevent chilling injury during cold disinfestation and to improve the external and internal quality of lemons

In 1988, 2 experiments were undertaken to test the effect of curing on the external and internal quality of lemons. The experiments were designed to determine the optimum postharvest handling regime for protecting lemons from chilling injury during the cold disinfestation process that is necessary for entry into markets such as Japan. In experiment 1, a mixture of Eureka and Lisbon lemons was cured for 0, 2,4, 8, 16, or 32 days at ambient temperature, then cold disinfested at 1�C for 16 days and stored for 4, 8, or 16 weeks at 10�C. In experiment 2, a mixture of Eureka and Lisbon lemons was treated with either thiabendazole (TBZ) (500 mg a.i./L) or sodium ortho-phenyl phenate (SOPP) (200 mg a.i./L) by bulk dipping before processing, or by an in-line spray during processing. The fruit was then cured for 0, 2, 4, 8, 16, or 32 days, cold disinfested as above, and stored at 10�C for 28 days. Curing for 16 days reduced chilling injury symptoms in experiment 1 but increased oleocellosis in experiment 2. Curing for 16 days also reduced the incidence of fungal breakdown caused by Penicillium spp. and Geotrichum candidum Lk. ex. Pers. When used as a bulk dip for pretreating lemons prior to curing, TBZ was more effective at controlling fungal breakdown than when used as an in-line spray, and more effective than SOPP used as a bulk dip or in-line spray. Red spotting of the rind was also reduced by bulk dipping in TBZ. Curing for 4 or more days produced increases in extractable juice. Development of yellow colour occurred during curing for 16-32 days and was enhanced by storage at 10�C. Curing for at least 4 days, when used in conjunction with a bulk dip of TBZ (500 mg a.i./L), can be used to protect lemons against fungal breakdown and to increase juice. Curing for 16-32 days can be used to develop even yellow coloration of the fruit and to decrease chilling injury.

Analysis of Post-Harvest Application Pesticides in Citrus Fruits

Analytical methods for 7 kinds of post-harvest application pesticides in citrus fruits and juices were established.Diphenyl (DP), o-phenylphenol (OPP) and 2, 4-D (2, 4-dichlorophenoxyacetic acid) were simultaneously extracted under acidic conditions, and thiabendazole (TBZ), imazalil, benomyl and sec-butylamine were simultaneously extracted under basic conditions. DP, OPP and 2, 4-D were determined by GC/MS (SIM) and imazalil, TBZ, benomyl and sec-butylamine were determined by HPLC with a UV or fluorescence detector. Recoveries of the 7 kinds of post-harvest application pesticides in lemon and lemon juice were 60.0-104.8% and 67.3-96.2%, respectively. Detection limits in citrus fruit and juice were 0.005-0.05ppm and 0.001-0.01ppm, respectively.

Residues of Post-Harvest Application Pesticides in Citrus Fruits after Storage and Processing into Lemon Marmalade

The residue levels of 8 pesticides in post-harvest-treated citrus during storage and processing into marmalade were investigated. Lemons, oranges and grapefruits were dipped in a solution of diphenyl (DP), o-phenyl phenol (OPP), 2, 4-dichlorophenoxyacetic acid (2, 4-D), imazalil, thiabendazole (TBZ), benomyl and sec-butylamine (BA), or fumigated with methyl bromide, and stored at 14°C followed by determination of residue levels at intervals of several days. As the result of 91 days' observation, the half lives of pesticides ranged from 36 days to in excess of 6 months. DP and imazalil were extremely stable and bromide gradually increased in the citrus fruits. On the 8th week of storage, lemons were processed into marmalade and the levels of pesticides were determined after each step. In the final product marmalade, 95% of DP, 41% of OPP, 42% of imazalil and 22% of bromide were found (ratio to initial contents), while no 2, 4-D, TBZ, benomyl or BA was detected.

Aneuploidy induction in mouse spermatocytes.

Assays for aneuploidy are being developed within a coordinated research program sponsored by the Commission of the European Communities. The 10 known and suspect spindle poisons colchicine (COL), econazole (EZ), chloral hydrate (CH), hydroquinone (HQ), diazepam (DZ), thiabendazole (TB), cadmium chloride (CD), pyrimethamine (PY), thimerosal (TM) and vinblastine (VBL) were tested for aneuploidy induction in male germ cells. Two different criteria were used for the evaluation of slides from testicular material of (102/El x C3H/El)F1 mice at different times (6, 14 and 22 h) after treatment with different doses of each of the test chemicals. Secondary spermatocytes of mice were evaluated by chromosome counting to determine the induction of hyperploidy. The proportions of spermatogonial mitoses, first and second meiotic metaphases were determined in order to recognize an effect of the test chemicals on testicular cell proliferation. COL, EZ, CH, HQ and VBL clearly increased the frequencies of hyperploid secondary spermatocytes which indicated non-disjunction induction during the first meiotic division. DZ and CD were less effective but significantly positive (P less than 0.05). Concomitantly, COL, EZ, CH, HQ, DZ, CD and VBL induced meiotic delay in primary and/or secondary spermatocytes. It is concluded that meiotic delay may be indicative for aneuploidy induction and the evaluation of changes in testicular cell proliferation described here could serve as a prescreen and partially substitute the time-consuming counting of metaphase chromosomes in secondary spermatocytes.

Studies on the Fate of Thiabendazole(TBZ) in Mice. IV. Nephropathy of Male and Female Mice Induced after Oral Administration of TBZ.

Studies on the Fate of Thiabendazole(TBZ) in Mice. IV. Nephropathy of Male and Female Mice Induced after Oral Administration of TBZ.

Effect of Forced, Hot-Air Treatment of Papaya Fruit on Fruit Quality and Incidence of Postharvest Diseases

Forced, hot-air (48.5°C for 3-4 h) treatment of pawpaw fruit (Carica papaya), a recently developed quarantine treatment for fruit flies, did not significantly reduce incidences of postharvest diseases compared with fungicide or hot-water treatments. However, when hot-air treatment was combined with thiabendazole (TBZ) (4 g a.i./litre) application or hot-water immersion (49° for 20 min), the incidence of most postharvest diseases was reduced, including those caused by Phomopsis sp., Botryodiplodia theobromae and Mycosphaerella sp. Although disease incidences were not significantly affected by the sequence of hot-air or hot-water application, degreening (lack of surface ripening), along with pitting and scalding symptoms significantly (P<0.01) increased when hot-water preceded hot-air treatment, but these symptoms did not occur when hot-air preceded hot-water treatment. The hot-air treatment was associated with an increase in the incidence of internal lumpiness (hardened lumps of flesh in ripe fruit) compared with untreated fruit.

High-Performance Liquid Chromatography of Fungicides in Citrus Fruits

Abstract The determination of three common citrus fungicides, diphenyl (DP), o-phenylphenol (oPP) and thiabendazole (TBZ), was investigated with reversed-phase high-performance liquid chromatography. DP and oPP were successfully chromatographed and quantitated by utilizing a reversed-phase Unisil Q C18 column after extraction with an essential oil distillation apparatus. An acetonitrile-0.1M H3PO4 (55:45) mobile phase was used. TBZ was chromatographed by using a Unisil Q C8 column with a mobile phase of acetonitrile-0.1M H3PO4 (80:20) after the extraction with ethyl acetate. The fungicides were detected with fluorescence detection at typical residue levels on citrus. The

Thiabendazole and Imazalil Applied at 53C Reduce Chilling Injury and Decay of Grapefruit

The fungicides thiabendazole (TBZ) or imazalil were applied at 1 g·liter-1 at 24 or 53C to `Marsh' and `Redblush' grapefruit (Citrus paradisi Macf.) to reduce fruit susceptibility to chilling injury (CI) and decay. Generally, there was more CI and decay on `Marsh' grapefruit than on `Redblush'. Severity of CI was lower in grapefruit that had been dipped at 53C than at 24C. Fruit dipped in fungicides had less CI than fruit dipped in water alone. Imazalil was more effective in reducing CI than TBZ. Fungicides reduced decay at both temperatures, and imazalil was better than TBZ. Chemical names used: 2-(4-thiazolyl)benzimidazole (thiabendazole, TBZ); 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl] -1H -imidazole (imazalil).

A possible biochemical mode of action for benzimidazole anthelmintics

Albendazole (ABZ), cambendazole (CBZ), oxibendazole (OBZ), and thiabendazole (TBZ) are potent, orally active, broad spectrum anthelmintics widely used in human and veterinary medicine. As members of the benzimidazole series, they are closely related chemically, and it is likely that they exert their anthelmintic effects in an identical fashion. We have examined the effects of these anthelmintics on the electrical resistance of planar bimolecular lipid membranes and compared the results with those obtained with a known uncoupler, 2,4-dinitrophenol (2,4-DNP). All drugs tested markedly reduced membrane resistance at concentrations lower than 0.1 μ m and were better proton conductors than 2,4-DNP by at least an order of magnitude. The sequence of proton conducting efficiency was ABZ > OBZ > TBZ > CBZ > 2,4-DNP. From 1 to 40 μ m, ABZ and CBZ substantially decreased P/0 (phosphorous/oxygen) ratios in coupled rat liver mitochondria in a concentration-dependent fashion using β-hydroxybutyrate as the substrate. 2,4-DNP was also shown to decrease P/0 ratios, but less effectively than the benzimidazole anthelmintics. These experiments indicate that the benzimidazole anthelmintics are lipid-soluble proton conductors that are effective in artificial (phospholipid bilayer) and natural (rat liver mitochondria) membrane systems. Dissipation of the transmembrane proton gradient should result in diminished levels of cellular ATP. In vivo treatment with a therapeutically effective dose of ABZ caused a severe disturbance in the energy balance of Hymenolepis diminuta; this was evident from a distinct drop in ATP levels, and from a decline in the ATP/ADP ratios, adenylate energy charge (AEC) and available adenylate energy (AAE) values. From these in vitro and in vivo experiments we conclude that benzimidazole anthelmintic activity, in part, may be due to bioenergetic disruptions resulting from transmembrane proton discharge.

Chronic oral toxicity and carcinogenicity study of thiabendazole in rats

The potential toxicity and carcinogenicity of thiabendazole (TBZ) was investigated in F344 rats. TBZ was given in pelleted diets at different dietary levels (0, 0.05, 0.1, 0.2 or 0.4%) to groups of 30 rats of each sex for 104 wk. Throughout the study, a marked decrease in body-weight gain was observed in males and females fed 0.4% TBZ. Transitional cell hyperplasia of the renal pelvis and/or papilla was observed in dosed groups of each sex with significant positive trends. Low incidence of transitional cell papilloma or carcinoma of the urinary system was recorded in the dosed groups. Preputial gland adenoma occurred in males treated with 0.4% TBZ, and the incidence was significantly higher than in controls. There was no clear-cut evidence of the carcinogenic activity of TBZ in the urinary system of male and female rats.

In vitro studies with nine known or suspected spindle poisons: results in tests for chromosome malsegregation in Aspergillus nidulans

Within the framework of a coordinated collaborative study for evaluating assays for aneuploidy, nine known or suspected spindle poisons were tested in mitotic segregation assays with Aspergillus nidulans. Experiments with A. nidulans diploid strain P1 revealed a statistically significant increase of whole chromosome segregants (non-disjunctional diploids and haploids) after treatments with chloral hydrate (CH), thiabendazole (TB), thimerosal (TM) econazole (EZ) and hydroquinone (HQ). The latter two chemicals also increased the frequency of mitotic cross-overs. Colchicine (COL), diazepam (DZ), cadmium chloride (CD) and pyrimethamine (PY) were ineffective. Further experiments with CH, TB, TM and EZ in the haploid strain 35 demonstrated that CH, TB and TM induced hyperploid types, thus indicating a primary effect on chromosome segregation in A. nidulans. However, since EZ did not induce putative hyperploids in strain 35 and trisomics in diploid 31, it is suggested that EZ affects chromosome segregation by an indirect mechanism, possibly related to induced structural chromosome damage, as previously shown for HQ.

Occurrence ofPenicillium digitatumandP. italicumResistant to Benomyl, Thiabendazole, and Imazalil on Citrus Fruit from Different Geographic Origins

In 1 yr, 1,287 isolates of Penicillium digiratum and P. italicum were collected from decayed mandarins (Citrus reticulata), oranges (C. sinensis), lemons (C. limon), and grapefruit (C. paradisi) at the wholesale markets in Rotterdam and Paris. The isolates were cultured on media with various fungicides and concentrations. Thirty-seven percent of the P. digitatum isolates grew at 4 and 10 mg/L of thiabendazole (TBZ), 35 and 34% grew at 4 and 10 mg/L of benomyl (BEN), respectively, and 17 and 12% grew at 0.2 and 0.5 mg/L of imazalil (IM), respectively

Evaluation of 10 chemicals for aneuploidy induction in the hexaploid wheat assay

This study was a part of an international project sponsored by the Commission of the European Communities to evaluate the utility of certain bioassays including hexaploid wheat assay to identify potential aneugens. Ten suspect spindle poisons, i.e. colchicine (COL), cadmium chloride (CdCl2), chloral hydrate (CH), diazepam (DIZ), econazole (EZ), hydroquinone (HQ), pyrimethamine (PY), thiabendazole (TB), thimerosal (TM), and vinblastin sulphate (VBL) were tested for their ability to induce green and/or white leaf sectors as indicators of loss or gain of a chromosome respectively, in Neatby's strain of Chinese Spring wheat (2n = 6x = 42). All the chemicals tested in this study, with the exception of CH and HQ yielded positive response.

Molecular analysis of selection for benzimidazole resistance in the sheep parasite Haemonchus contortus

The molecular basis for the resistance of the sheep parasitic nematode Haemonchus contortus to the benzimidazole (BZ) group of anthelmintics was investigated. Three BZ-susceptible and three resistant populations from different geographical locations were characterized with respect to the egg-hatch assay with thiabendazole (TBZ), mebendazole (MBZ) binding tests and restriction fragment length polymorphism (RFLP) after Southern blotting. Cloned H. contortus α- and β-tubulin genes were used as probes to analyze the RFLPs of genomic DNA prepared from mixtures of infectious larvae (L3) or adults. The susceptible populations showed, with both α- and β-tubulin probes, 2 to 6 different fragments, depending on the restriction enzyme used. The three resistant populations showed as many fragments with the α-tubulin probe as the susceptible populations, but when probed with β-tubulin only 1 or 2 fragments were visible, but always less than in the susceptible populations. An in vitro selection experiment was carried out using a susceptible population that was isolated in the laboratory before BZ came on the market. The results showed that after two selections with increasing amounts of TBZ, the population had become resistant, according to the egg-hatch assay values and MBZ binding assay. Using RFPL, the number of β-tubulin probe reactive DNA fragments was reduced from 5 to 1. Analysis of the DNA of individual male adults of susceptible populations indicated a heterogeneity among the individual worms regarding the number of β-tubulin probe reactive fragments (1 to 4) and frequency of the specific fragments. Usually, only one specific fragment (9 kb) was found in the resistant individuals. This 9-kb fragment was already present in some individuals in the susceptible population although it was in combination with other fragments. This would imply that genes conferring BZ resistance were present in H. contortus populations before BZ came on the market, and could explain the fast selection for BZ resistance in the field.

REDUCING CHILLING INJURY AND DECAY Of GRAPEFRUIT BY FUNGICIDES APPLIED AT HIGH TEMPERATURE

The fungicides thiabendazole (TBZ) or imazalil were applied at 1 g·liter-1 at 24 or 53C to `Marsh' and `Redblush' grapefruit (Citrus paradis i Macf.) to reduce fruit susceptibility to chilling injury (CI) and decay. There was more CI and decay on `Marsh' grapefruit than on `Redblush'. CI was found to be lower in grapefruit that had been dipped at 53C than at 24C. CI was higher after water dips without fungicide. Imazalil was found to be more effective in reducing CI than TBZ. Fungicides reduced decay at both temperatures, and imazalil was better than TBZ. Results of this study confirm the benefits of high-temperature fungicide treatments for maintaining grapefruit quality and indicate some benefits of high-temperature fungicide treatments for reducing CI.

Evaluation of Additives to Endophyte-Infected Fescue Hay on Growth Performance and Body Temperature of Steers

Endophyte-infected fescue hay (EIFH) was harvested during May from a pasture from a 100% Acremonium coenophialum infection. The effects of feeding treatments 1) EIFH, 2) EIFH with lasalocid, 3) ammoniated EIFH, 4) EIFH with acetylsalicylic acid (ASA), 5) EIFH with selenium-zinc-vitamin E (SeZnE), and 6) EIFH with thiabendazole (TBZ) on gain, body temperature, hay consumption, and feed efficiency were evaluated for a 56-d period during September and October. Forty-eight Hereford x Angus steers averaging 207kg were selected for tendency to elevate body temperature when given access to 100% endophyte-infected fescue pasture. Steers were fed individually and hay was offered at a rate of 2.4% of shrunk body weight, which was adjusted after 28 d. Feed consumption was recorded daily and individual body temperatures were taken twice weekly. Steers were supplemented daily with .9kg of ground shelled corn containing the specified treatment compound. A mineral mixture was provided free choice. Steers fed the ammoniated EIFH gained more (P<.05) than those fed EIFH or EIFH with TBZ. Temperatures of steers fed ammoniated EIFH were lower during the second 28 d than for all other treatments and were lower (P<.05) after 56 d than those of steers fed EIFH (control), EIFH with lasalocid, or EIFH with TBZ. Lasalocid, ASA, SeZnE, or TBZ did not increase gain or decrease body temperature when compared to steers fed EIFH.

Determination of Thiabendazole, 5-Hydroxythiabendazole, Fenbendazole, and Oxfendazole in Milk

The liquid chromatographic determination previously developed for benzimidazoles in cattle liver has been slightly modified and applied to the determination of 4 benzimidazoles in milk. Recoveries of fenbendazole (FBZ), oxfendazole (OFZ), and thiabendazole (TBZ) from milk fortified at the 10 ppb level were 80% or greater with an intralaboratory coefficient of variation of 11% or less. Recovery of 5-hydroxythiabendazole (5-OH-TBZ) at the 30 ppb level averaged 56% with an intralaboratory coefficient of variation of 5%. Limited data on the depletion of FBZ, OFZ, TBZ, and 5-OH-TBZ in milk were also generated.