Parasitology & Microbiology Research Laboratory, Department of Zoology, The University of Burdwan, Burdwan, West Bengal, India.
Chandannagar College, Chandannagar, West Bengal, India.
Appl Biochem Biotechnol. 2022 Dec;194(12):6126-6139. doi: 10.1007/s12010-022-03970-0. Epub 2022 Jul 27.
The ideal condition of earthworm gut promotes growth and multiplication of beneficial soil microorganisms eliminating pathogens and converts organic wastes into nutrients rich compost. The present study has been carried out to determine the population dynamics of earthworm gut bacteria and to find out relative abundance of different functional bacterial groups in the foregut, midgut, and hindgut of earthworm Perionyx excavatus. To assess bacterial diversity, a viable plate count method was adopted. In the different gut region of earthworm, aerobic heterotrophic, amylolytic, Bacillus, Gram-negative, proteolytic, fat hydrolyzing, nitrate-reducing, nitrifying, asymbiotic nitrogen-fixing, Azotobacter, and phosphate solubilizing bacterial populations ranged from 22.2 to 241.6 × 10, 8.0 to 171.60 × 10, 1.83 to 2.79 × 10, 10.68 to 23.04 × 10, 3.70 to 5.52 × 10, 59.60 to 208.40 × 10, 1.86 to 7.34 × 10, 10.94 to 19.78 × 10, 0.80 to 3.42 × 10, 7.83 to 13.70 × 10, 1.31 to 2.67 × 10 cfu/ml gut suspension, respectively. The results of the one-way ANOVA revealed that the bacterial load of most of the bacterial groups was significantly higher (p < 0.05) in the hindgut region, followed by midgut and foregut. Only the density of the proteolytic group was significantly higher (p < 0.05) in the midgut region followed by foregut and hindgut. Starch hydrolyzing bacteria constitute the largest group of bacteria in the gut content. From principal component analysis, two components were extracted with the eigenvalues of 8.485 and 1.132. Agglomerative hierarchical cluster analysis revealed that the bacterial populations were clustered into four different groups. Quantitative variation among bacterial groups in earthworm's gut seems to determine the soil health and composting efficiency; from this point of view, the present study will provide a better understanding about different functional bacterial groups of earthworm's guts and might be helpful in sustainable agriculture and waste management.
蚯蚓肠道的理想条件促进有益土壤微生物的生长和繁殖，消除病原体，并将有机废物转化为富含营养的堆肥。本研究旨在确定蚯蚓肠道细菌的种群动态，并找出蚯蚓 Perionyx excavatus 前肠、中肠和后肠中不同功能细菌群体的相对丰度。为了评估细菌多样性，采用了可培养平板计数法。在蚯蚓的不同肠道区域，好氧异养菌、淀粉分解菌、芽孢杆菌、革兰氏阴性菌、蛋白酶、脂肪水解菌、硝酸盐还原菌、硝化菌、共生固氮菌、固氮菌和溶磷菌的数量范围分别为 22.2 到 241.6×10、8.0 到 171.60×10、1.83 到 2.79×10、10.68 到 23.04×10、3.70 到 5.52×10、59.60 到 208.40×10、1.86 到 7.34×10、10.94 到 19.78×10、0.80 到 3.42×10、7.83 到 13.70×10、1.31 到 2.67×10 cfu/ml 肠道悬浮液。单向方差分析的结果表明，大多数细菌群体的细菌负荷在后肠区域显著更高（p<0.05），其次是中肠和前肠。只有蛋白酶组的密度在后肠区域显著更高（p<0.05），其次是前肠和中肠。淀粉水解菌构成肠道内容物中最大的细菌群体。从主成分分析中，提取了两个具有特征值 8.485 和 1.132 的分量。凝聚层次聚类分析表明，细菌种群聚集成四个不同的组。蚯蚓肠道中细菌群体的定量变化似乎决定了土壤健康和堆肥效率；从这个角度来看，本研究将提供对蚯蚓肠道不同功能细菌群体的更好理解，并可能有助于可持续农业和废物管理。
