Effect of 2, 6-Dichlorobenzonitrile on Amoebicidal Activity of Multipurpose Contact Lens Disinfecting Solutions

Multipurpose contact lens disinfecting solutions (MPDS) are widely used to cleanse and disinfect microorganisms. However, disinfection efficacy of these MPDS against Acanthamoeba cyst remain insufficient. 2, 6-dichlorobenzonitrile (DCB), a cellulose synthesis inhibitor, is capable of increasing the amoebical effect against Acanthamoeba by inhibiting its encystation. In this study, we investigated the possibility of DCB as a disinfecting agent to improve the amoebicidal activity of MPDS against Acanthamoeba cyst. Eight commercial MPDS (from a to h) were assessed, all of which displayed insufficient amoebicidal activity against the mature cysts. Solution e, f, and h showed strong amoebicidal effect on the immature cysts. Amoebicidal efficacy against mature cysts remained inadequate even when the 8 MPDS were combined with 100 μM DCB. However, 4 kinds of MPDS (solution d, e, f, and h) including 100 μM DCB demonstrated strong amoebicidal activity against the immature cysts. The amoebicidal activity of solution d was increased by addition of DCB. Cytotoxicity was absent in human corneal epithelial cells treated with either DCB or mixture of DCB with MPDS. These results suggested that DCB can enhance the amoebicical activity of MPDS against Acanthamoeba immature cyst in vitro.

Hydrogen sulfide alleviates chlorobenzene toxicity in soybean seedlings / Sulfeto de hidrogênio e clorobenzeno na toxicidade da soja

ABSTRACT: As a gas signaling molecule, endogenous hydrogen sulfide (H2S) plays a crucial role in the plant stress response. However, the role of H2S in the response to organic pollutants specifically has not been studied. Here, the effects of H2S addition on soybean (Glycine max) seedlings tolerance of 1,4-dichlorobenzene (1,4-DCB) were investigated. Under 1,4-DCB stress, the growth of soybean seedlings roots and stems was inhibited, while L-/D-cysteine desulfhydrase (LCD/DCD) activity was induced and endogenous H2S increased. When applied jointly with sodium hydrosulfide (NaHS), a H2S donor, root growth inhibition was effectively alleviated. Pre-treatment of seedlings with 0.4mmol L-1 NaHS reduced the malondialdehyde (MDA) and reactived oxygen species (ROS) content, mitigating root cell toxicity significantly. Further experiments confirmed that NaHS enhanced soybean seedlings peroxidase (POD) and superoxide dismutase (SOD) enzyme activities. In contrast, these effects were reversed by hypotaurine (HT), a H2S scavenger. Therefore, H2S alleviated 1,4-DCB toxicity in soybean seedlings by regulating antioxidant enzyme activity to reduce cell oxidative damage.

RESUMO: Tal como uma molécula de sinal de gás, sulfureto de hidrogenio endógena (H2S) desempenha um papel crucial na resposta ao stress das plantas. Mas não foi relatado o papel de H2S em plantas poluentes orgânicos stress. Este estudo sobre a variação de H2S envolvido em plântulas de soja tolerância 1,4-Diclorobenzeno foi investigada. Os resultados mostraram sob o 1,4-diclorobenzeno stress, que o crescimento da soja (Glycine max) de raiz de mudas e caule foram inibidas, L- / D-cisteína desulfhydrase (LCD / DCD) atividades enzimáticas foram empossados, em seguida, H2S endógeno aumentado. Quando aplicado com hidrossulfureto de sódio (NaSH), um doador de H2S, raiz de plântulas de soja, a inibição do crescimento pode ser melhorada. Tratamentos prévios com 0,4mmol L-1 NaHS, malondialdeído (MDA) e espécies de oxigênio reactivas conteúdo (ROS) foi reduzida, em seguida, a toxicidade celular da raiz foi reduzida significativamente. Outros experimentos confirmaram que NaSH melhorou a peroxidase de plântulas de soja (POD), superóxido dismutase (SOD) atividades enzimáticas. Em contraste, estes efeitos foram revertidos por hypotaurine (HT), um eliminador de H2S. Então H2S pode aliviar toxicidade 1,4-diclorobenzeno em plântulas de soja por meio da regulamentação das atividades de enzimas antioxidantes para manter a integridade da estrutura celular.