Department of Zoology, Gauhati University, Guwahati 781 014, India.
J Biosci. 2024;49.
Muga is a semi-domesticated multi-voltine silkworm cultivated in different seasons of the year. Crops are reared in specific months and are traditionally named Jarua (spring), Chotua, Bohogua, Jethua, Aherua, Saonia, Bhodia, Ahinia, Katia (autumn) and Aghonia. Seasonal variation forces silkworm larvae to face harsh environmental conditions manifested by generation of oxidative stress and occurrence of microbial diseases. Anti-oxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) along with anti-microbial peptides like cecropin, gloverin, and defensin in lepidopterans play a significant role in fighting against free radicals as well as disease-causing microbes, and hence this study has focussed on the expression of anti-oxidant enzyme activity and different anti-microbial peptides in three distinct crops, namely, Jarua and Aherua (seed crops) and Katia (commercial crop) collected from the same site, Khanapara (26°09'34.62″N; 91°41'27.23″E) in Assam, India. The results of biochemical enzyme assays revealed the Jarua crop to possess the highest enzyme activity with respect to SOD and GST in particular, followed by the Katia and Aherua crops. Malondialdehyde lipid peroxidase and reduced glutathione were also expressed notably in the Jarua crop. The quantitative polymerase chain reaction (qPCR) study involving analysis of anti-microbial peptide (AMP) expression revealed the Jarua crop to possess the highest expression of three AMPs, viz., gloverin, moricin 1 and gallerimycin pro, followed by Katia with the highest expression of attacin and defensin. Total haemocyte count revealed Jarua to induce the least haemocyte count, Katia to induce moderate, and Aherua to induce the highest count. Thus, our findings indicate that although the Jarua crop is considered a seed crop, it can be reconsidered as a commercial crop due to its high concentration of anti-oxidant enzymes and higher expression of AMPs. This study was carried out to focus on the immunological response of the muga silkworm with varying seasons. Their innate immunity helps them fight against diseases that emerge under different environmental conditions in which anti-microbial peptides play a crucial role. Muga larvae are reared for silk and are used commercially to produce various commodities for which the best silk thread should always be identified to obtain a higher market value.
木贾蚕是一种半驯化的多化性蚕，在一年中的不同季节饲养。蚕在特定的月份饲养，传统上分别命名为 Jarua（春季）、Chotua、Bohogua、Jethua、Aherua、Saonia、Bhodia、Ahinia、Katia（秋季）和 Aghonia。季节性变化迫使蚕幼虫面临恶劣的环境条件，表现为产生氧化应激和发生微生物疾病。超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽-S-转移酶（GST）等抗氧化酶以及鳞翅目动物中的抗菌肽如 Cecropin、Gloverin 和 Defensin 等在对抗自由基和致病微生物方面发挥着重要作用，因此本研究集中在三个不同蚕种（Jarua 和 Aherua（种子蚕）和 Katia（商品蚕））的抗氧化酶活性和不同抗菌肽的表达，这些蚕种均来自印度阿萨姆邦的汗帕拉（26°09'34.62″N；91°41'27.23″E）。生化酶分析的结果表明，Jarua 蚕种的 SOD 和 GST 酶活性最高，其次是 Katia 和 Aherua 蚕种。丙二醛脂质过氧化物酶和还原型谷胱甘肽在 Jarua 蚕种中也有明显表达。涉及抗菌肽（AMP）表达分析的定量聚合酶链反应（qPCR）研究表明，Jarua 蚕种表达三种 AMP（gloverin、moricin 1 和 gallerimycin pro）的表达水平最高，其次是 Katia 蚕种，attacin 和 defensin 的表达水平最高。总血细胞计数显示，Jarua 诱导的血细胞计数最少，Katia 诱导的血细胞计数中等，Aherua 诱导的血细胞计数最高。因此，我们的研究结果表明，尽管 Jarua 蚕种被认为是一种种子蚕，但由于其抗氧化酶浓度高且抗菌肽表达水平高，它可以被重新视为一种商品蚕。本研究旨在关注不同季节的木贾蚕的免疫反应。它们的先天免疫有助于它们对抗不同环境条件下出现的疾病，而抗菌肽在其中发挥着关键作用。木贾蚕幼虫被饲养用于丝绸，并被商业用于生产各种商品，为了获得更高的市场价值，应该始终确定最好的丝线。
