Analysis of the effects of nanosilver on bacterial community in the intestinal fluid of silkworms using high-throughput sequencing

2019 ◽  
Vol 110 (3) ◽  
pp. 309-320
Author(s):  
Chen Lin ◽  
Zhou Wei ◽  
Zhou Yi ◽  
Tan Tingting ◽  
Du Huamao ◽  
...  

AbstractNanosilver is an environment-friendly, harmless alternative of traditional disinfectants which can be potentially applied in the sericulture industry. However, the effects of nanosilver on the intestinal bacterial community of the silkworms (Bombyx mori L.) are unclear. In this study, Illumina MiSeq high-throughput sequencing technology was used to assess the intestinal bacterial community in both male and female silkworms while treated with different concentrations of nanosilver. We found that nanosilver significantly influenced the composition of silkworm intestinal bacterial community on the different taxonomic levels. Most conspicuously, the abundance of Firmicutes was increased by the treatment of 20 mg L−1 nanosilver but decreased by that of 100 mg L−1 nanosilver at the phylum level. The same trend was observed in Bacilli at the class level and in Enterococcus at the genus level. In some extreme cases, application of nanosilver eliminated the bacterium, e.g., Brevibacillus, but increased the population of several other bacteria in the host intestine, such as Blautia, Terrisporobacter, Faecalibacterium, and some bacteria could only be found in nanosilver treatment groups, e.g., Dialister. In addition, although nanosilver generally showed negative effects on the cocooning rate in a dose-dependent manner, we found that 20 mg L−1 nanosilver treatment significantly increased the body weight of silkworms and did not show negative effects on the survival rate. These results indicated that the intestinal bacteria community of silkworm larvae was significantly changed after nanosilver treatment which might consequently influence host growth and development.

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2352
Author(s):  
Xia Wan ◽  
Yu Jiang ◽  
Yuyan Cao ◽  
Binghua Sun ◽  
Xingjia Xiang

Odontolabis fallaciosa (Coleoptera: Lucanidae) is a giant and popular stag beetle with striking sexual dimorphism and male trimorphism. However, little is known about their intestinal microbiota, which might play an indispensable role in shaping the health of their hosts. The aim of this study was to investigate the intestinal bacterial community structure between the two sexes and among three male morphs of O. fallaciosa from China using high-throughput sequencing (Illumina MiSeq). The gut bacterial community structure was significantly different between males and females, suggesting that sex appeared to be the crucial factor shaping the intestinal bacterial community. Females had higher bacterial alpha-diversity than males. There was little difference in gut bacterial community structure among the three male morphs. However, compared to medium and small males, large individuals were associated with the higher relative abundance of Firmicutes and Firmicutes/Bacteroides (F/B) ratio, which might contribute to nutritional efficiency. Overall, these results might help to further our understanding of beetle–bacterial interactions of O. fallaciosa between the two sexes, and among the three male morphs.


2019 ◽  
Author(s):  
Huan Li ◽  
Lu Yuan ◽  
Ruina Liu ◽  
Siruo Zhang ◽  
E Yang ◽  
...  

Abstract Background The human rectum flora consists of a huge variety of bacteria and the association between individuals and their rectum bacterial community begins presently after birth and continues the whole lifetime. Once the body dies, the inherent microbes begin to break down from the inside and play a key role thereafter. Results The aim of this study was to investigate the probable shift of the rectum flora at different time intervals up to 15 days after death and to characterize the contribution for of this shift to estimate the time of death. The rectum of rats was wiped with a sterile cotton swab and the samples were proceeded for DNA extraction, PCR amplification of the 16S rRNA gene with the V3+V4 variable regions, and high throughput sequencing carried out on IonS5TMXL platform. The results were analyzed for intra-group and inter-group diversity, similarity and difference at different time points. At phylum level, Proteobacteria and Firmicutes showed major shifts, checked at 11 different intervals and emerged in the most of postmortem intervals. At the genus level, Enterococcus appeared in all groups except alive samples, Lactobacillus and Proteus appeared in most time points, and the latter showed an increasing trend after 3 days postmortem samples. At the species level, Enterococcus_faecalis and Proteus_mirabilis existed in most postmortem intervals, and the former had a downward trend after day 5 postmortem, while the latter had an upward trend. Corynebacterium_amycolatum , Entero_isolate_group_2 , Bacteroides_uniformis , Enterococcus_faecalis , Streptococcus_gallolyticus_subsp_macedonics , Clostridium_sporogenes were more abundant in 0-hour, day 1, 3, 5, 7, 13 postmortem intervals, respectively, while Proteus_mirabilis and Vagococcus_lutrae were abundant in day 15 postmortem. In addition, functional capacity analysis of Membrane_Transport, Amino_Acid_Metabolism, Nucleotide_Metabolism and Energy_Metabolism showed significant differences between alive and almost all other time points after death ( P <0.05). Conclusions All in all, bacteria at different levels (phylum, genera, species) showed different characteristic during the process of decomposition and possessed entirely different relative abundance and the structure of bacterial community in each time point shifted obviously, which suggested that the specific bacteria might imply the specific postmortem interval during decomposition.


2020 ◽  
Author(s):  
Huan Li ◽  
Siruo Zhang ◽  
Ruina Liu ◽  
Lu Yuan ◽  
Di Wu ◽  
...  

Abstract Once the body dies, the inherent microbes of the host begin to break down from the inside and play a key role thereafter. It is hypothesized that after the death certain rectal microbes would change during the decomposition course in the body. This study aimed to investigate the probable shift in the composition of the rectal flora at different time intervals up to 15 days after death and to explore bacterial taxa important for estimating the time of death. At the phylum level, Proteobacteria and Firmicutes showed major shifts, when checked at 11 different intervals, and emerged at most of the postmortem intervals. At the species level, Enterococcus faecalis and Proteus mirabilis existed at most postmortem intervals; the former showed a downward trend after day 5 postmortem, while the latter showed an upward trend. There were obvious differences in bacterial community structure and richness at the phylum, genus, and species levels during the decomposition of the corpse of rats. The phylum, genus, and species taxa richness decreased initially and then increased significantly. The turning point came on day 9 when genus, rather than phylum or species, contained the most information for estimating the time of death. We constructed a prediction model using genus taxon data from high-throughput sequencing, which explained 87.2% of the time since the first sampling within 1 h. Seven bacteria, namely Enterococcus, Proteus, Lactobacillus, unidentified Clostridiales, Vagococcus, unidentified Corynebacteriaceae, and unidentified Enterobacteriaceae, were included in this model. The above-mentioned bacteria showed a promising future for estimating the shortest time of death and results of current study were agreeing with the proposed hypothesis.


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