River, Life and Livelihood

 

River protection and biodiversity conservation

 

Brahmaputra River, Mymensingh

 

The Brahmaputra, also known as the Yarlung Tsangpo in Tibet, the Siang/Dihang River in Arunachal Pradesh, and Luit, Dilao in Assam, is a trans-boundary river which flows through Tibet, India, and Bangladesh. It is the 9th largest river in the world by discharge, and the 15th longest. It flows some 1,800 miles (2,900 km) from its source in the Himalayas to its confluence with the Ganges (Ganga) River, after which the mingled waters of the two rivers empty into the Bay of Bengal.

 

Gaibanda, the Old Brahmaputra leaves the left bank of the main stream and flows past Jamalpur and Mymensingh to join the Meghna River at Bhairab Bazar.) Before its confluence with the Ganges, the Jamuna receives the combined waters of the Baral, Atrai, and Hurasagar rivers on its right bank and becomes the point of departure of the large Dhaleswari River on its left bank. A tributary of the Dhaleswari, the Buriganga (“Old Ganges”), flows past Dhaka, the capital of Bangladesh, and joins the Meghna River above Munshiganj.

 

Exposure to Dodecamethylcyclohexasiloxane (D6) Affects the Antioxidant Response and Gene Expression of Procambarus clarkii

Md Muzammel Hossain

^1,2,3,

Yuan Yuan

¹,

Hengliang Huang

¹,

Ziwei Wang

¹,

Mohammad Abdul Baki

³,

Zhihua Dai

^1,4,

Muhammad Rizwan

^1,5,

Shuanglian Xiong

¹,

Menghua Cao

¹ and

Shuxin Tu

^1,2,*

Dodecamethylcyclohexasiloxane (D6) is widely used daily in the chemical industry and exists in the environment; however, its eco-toxicity is not well documented. A hydroponic experiment was performed to investigate the effects of D6 exposure (10–1000 mg L⁻¹) on oxidative stress induction and gene expression changes in crayfish (Procambarus clarkii). The results showed that superoxide dismutase (SOD) activity was enhanced by 20–32% at low D6 exposure (10 mg L⁻¹) in muscle but reduced in gill tissue at high D6 exposure (1000 mg L⁻¹). High D6 (1000 mg L⁻¹) also increased catalase (CAT) and peroxidase (POD) activities in muscle tissue by 14–37% and 14–45%, respectively, and the same trend was observed in the carapace and gill tissue of crayfish. The Malondialdehyde (MDA), ascorbate (AsA), and glutathione (GSH) contents were increased by 16–31%, 19–31%, and 21–28% in the muscle of crayfish under D6 exposure. Additionally, silicon (Si) content increased in three organs (gill, carapace, and muscle) of crayfish. Related genes involved in enzyme and nonenzyme activities were detected, and when crayfish was exposed to D6, genes such as Sod3, Cat3, Pod3, and Gsh3 were up-regulated, while Asa3 and Oxido3 were significantly down-regulated in the muscle. The research results help us to understand the toxicity of D6 in crayfish and provide a basis for further research on the mechanism of D6-induced stress in crayfish and other aquatic organisms. View Full-Text

Keywords: silicone; D6; antioxidation; transcriptome; crayfish

Sources: Sustainability 2021, 13(6), 3495; https://doi.org/10.3390/su13063495

 

Silicone stressed response of crayfish (Procambarus clarkii) in antioxidant enzyme activity and related gene expression

Md Muzammel Hossain^aHengliang Huang^aYuan Yuan^aTianyin Wan^aChengfeng Jiang^aZhihua Dai^aShuanglian Xiong^aMenghua Cao^aShuxin Tu^ab

Organosilicon has been widely used in various fields of industry and agriculture due to its excellent properties, such as high and low temperature resistance, flame retardan, insulation, radiation resistance and physiological inertia. However, organosilicon toxicity in aquatic animals is seldom known. In this research, two typical silicone or silane coupling agents (KH-560 (3-Glycidoxypropyltrimethoxysilane) and KH-570 (3-Methacryloxypropyltrimethoxysilane)) were used in a hydroponic experiment to evaluate the effects on survival rate, antioxidant response and gene expression in red swamp crayfish (Procambarus clarkii). Crayfishes were grown in black aquaculture boxes containing different concentrations (0, 10, 100 and 1000 mg L⁻¹) of KH-560 and KH-570 for 72 h, and then crayfish samples were harvested and separated into tissues of carapace, gill and muscle for analysis. The results showed that silicone significantly increased malondialdehyde (MDA) content in muscle by 17%–38% except for the treatment of 100 mg L⁻¹ KH-570, and reduced the survival rate of crayfish. Additionally, silicone KH-570 increased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) by 15%–31%, 17%–35%, and 9%–46%, as well as the contents of ascorbate (AsA) and glutathione (GSH) by 19%–31%, and 23%–29% respectively, in muscle tissue, and similar results occurred in KH-560. In the carapace, however, SOD activity was significantly decreased at high concentrations level of both silicone treatments. Moreover, silicon (Si) content was higher in the abdominal muscle of crayfish after silicone treatment. Assay of gene expression showed an obvious increasing expression of antioxidant related genes (Sod1, Sod2, Cat1, Cat2, and Pod1, Pod2) under silicone stress. The above results suggested that silicone caused an obvious stress response in crayfish in both biochemical and molecular levels.

Sources, Environmental Pollution, Volume 274, 1 April 2021, 115836: https://doi.org/10.1016/j.envpol.2020.115836