ABSTRACT
Eucryptorrhynchus brandti and Eucryptorrhynchus scrobiculatus (Coleoptera: Curculionidae) are two monophagous weevil pests that feed on Ailanthus altissima (Mill.) Swingle but differ in their diet niche. In the field, adults of E. brandti prefer to feed on the trunk of A. altissima, whereas adults of E. scrobiculatus prefer to feed on the tender parts. We conducted Illumina sequencing of 16S rRNA to examine changes in bacterial diversity in the adults of these two weevil species after they fed on different parts of A. altissima (trunk, 2-3-year-old branches, annual branches, and petioles). Proteobacteria, Tenericutes, and Firmicutes were the dominant phyla in E. brandti (relative abundance was 50.64, 41.56, and 5.63%, respectively) and E. scrobiculatus (relative abundance was 78.63, 11.91, and 7.41%, respectively). At the genus level, Spiroplasma, endosymbionts2, Unclassified Enterobacteriaceae, and Lactococcus were dominant in E. brandti, and Unclassified Enterobacteriaceae, Wolbachia and Spiroplasma, and endosymbionts2 were dominant in E. scrobiculatus. Linear discriminant analysis effect size analysis revealed microbial biomarkers in the different treatment group of adults of both weevil species. Adults of E. brandti may require the trunk, and adults of E. scrobiculatus may require the petioles and annual branches to maintain the high diversity of their gut microbes. The results of this study indicate that feeding on different parts of A. altissima affects the composition and function of the microbes of E. brandti and the microbial composition of E. scrobiculatus. Variation in the abundance of Wolbachia and Spiroplasma in E. brandti and E. scrobiculatus is associated with dietary niche changes, and this might explain the evolution of reproductive isolation between these two sibling weevil species.
ABSTRACT
Exploring the effects of exogenous iron (Fe) on cadmium (Cd) in rice is of great significance for ensuring food security. The accumulation of Cd and the changes in the microbial community structure in rice roots under three Fe concentrations (5, 50, and 500 µmol·L-1 EDTA-Na2Fe) were studied through a hydroponic experiment. The results showed that the increase in the environmental Fe concentration promoted the formation of iron plaque on the rice roots, and both Fe-deficiency and Fe-sufficiency would enhance the adsorption and fixation of Cd on the root surface. Compared with that of normal Fe levels (50 µmol·L-1), Fe deficiency increased Cd accumulation in rice roots and shoots by 49.76% and 15.68%, respectively. Although Fe sufficiency also increased Cd accumulation in the roots by 18.39%, the Cd concentration in shoots was significantly reduced by 35.95% compared with that of the normal Fe. 16S rRNA high-throughput sequencing was used to determine the root microbial community structure, and through PCA, LEfSe, and RDA analysis, it was found that compared with normal Fe, an Fe-deficient environment reduced the abundance and uniformity of root microbes. Proteobacteria and Bacteroidetes at the phylum level were the dominant flora, Fe deficiency inhibited the increase in the relative abundance of Bacteroidetes, and high-concentration Fe reduced the relative abundance of Proteobacteria. At the genus level, the relative abundance of functional microorganisms Ensifer, Rhodopila, Bdellovibrio, and Dyella were different under different Fe environments, which may have affected the absorption and accumulation of Cd by rice by affecting the formation of Fe plaque on the root and other biochemical processes. In addition, the effect of an Fe-deficient environment on microbial functions was higher than that of the Fe sufficient environment. This study investigated the changes in the rice root microbial community structure and the ability of rice to absorb and transport Cd under different Fe environments, which provided a theoretical basis and an important reference for the inhibition of Fe on Cd accumulation in rice in Cd-polluted paddy soil in southern China.
Subject(s)
Microbiota , Oryza , Soil Pollutants , Cadmium/analysis , Iron/chemistry , Oryza/chemistry , Plant Roots/chemistry , RNA, Ribosomal, 16S , Soil/chemistry , Soil Pollutants/analysisABSTRACT
PURPOSE: To study the stability of the microscrew implant anchorage under different loading force and different timing and observe the integration of the implant to the bone. METHODS: Thirty-six titanium alloy microscrew implants were implanted into three dogs' maxilla and mandible. The implants were divided into two groups: one with immediate implant loading and the other with delayed implant loading. In the delayed loading group, the microscrew implants that were implanted into the right maxilla and mandible were unloaded temporarily. Four weeks later, these dogs, together with the immediate loading group, whose microscrew implants were implanted into the left maxilla and mandible, were loaded at the same time. The mesial screw was unloaded. Two distal screws were loaded with force: 1.96N on the maxilla, and 3.92N on the mandibular. After 12 weeks, the dogs were sacrificed. The specimen were fixed and decalcified. Subsequently, immunohistochemical stain for BMP-2 was employed. The specimen were assessed with image analysis system to analyze the average grey scale. The data were analyzed using Student's t test and one-way ANOVA with SPSS 10.0 software package. RESULTS: BMP-2 staining showed that there was significant difference between the immediate loading group(1.96N,3.92N), delayed loading group(1.96N,3.92N) and non-loading group at average gray value (P<0.05). But there was no significant difference between the immediate loading group and delayed loading group (P>0.05). CONCLUSIONS: Both the immediate and the delayed implant loading can strengthen the attachment and integration of the implant to the bone. The timing of the loading force has no significant impact on the stabilization of the microscrew implants.
