Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States of America.
Computational Intelligence to Predict Health and Environmental Risks (CIPHER) Center, University of North Carolina at Charlotte, Charlotte, NC, United States of America.
PeerJ. 2024 May 20;12:e17349. doi: 10.7717/peerj.17349. eCollection 2024.
Antibiotics are commonly used for controlling microbial growth in diseased organisms. However, antibiotic treatments during early developmental stages can have negative impacts on development and physiology that could offset the positive effects of reducing or eliminating pathogens. Similarly, antibiotics can shift the microbial community due to differential effectiveness on resistant and susceptible bacteria. Though antibiotic application does not typically result in mortality of marine invertebrates, little is known about the developmental and transcriptional effects. These sublethal effects could reduce the fitness of the host organism and lead to negative changes after removal of the antibiotics. Here, we quantify the impact of antibiotic treatment on development, gene expression, and the culturable bacterial community of a model cnidarian, .
Ampicillin, streptomycin, rifampicin, and neomycin were compared individually at two concentrations, 50 and 200 µg mL, and in combination at 50 µg mL each, to assess their impact on . First, we determined the impact antibiotics have on larval development. Next Amplicon 16S rDNA gene sequencing was used to compare the culturable bacteria that persist after antibiotic treatment to determine how these treatments may differentially select against the native microbiome. Lastly, we determined how acute (3-day) and chronic (8-day) antibiotic treatments impact gene expression of adult anemones.
Under most exposures, the time of larval settlement extended as the concentration of antibiotics increased and had the longest delay of 3 days in the combination treatment. Culturable bacteria persisted through a majority of exposures where we identified 359 amplicon sequence variants (ASVs). The largest proportion of bacteria belonged to Gammaproteobacteria, and the most common ASVs were identified as and . The acute antibiotic exposure resulted in differential expression of genes related to epigenetic mechanisms and neural processes, while constant application resulted in upregulation of chaperones and downregulation of mitochondrial genes when compared to controls. Gene Ontology analyses identified overall depletion of terms related to development and metabolism in both antibiotic treatments.
Antibiotics resulted in a significant increase to settlement time of larvae. Culturable bacterial species after antibiotic treatments were taxonomically diverse. Additionally, the transcriptional effects of antibiotics, and after their removal result in significant differences in gene expression that may impact the physiology of the anemone, which may include removal of bacterial signaling on anemone gene expression. Our research suggests that impacts of antibiotics beyond the reduction of bacteria may be important to consider when they are applied to aquatic invertebrates including reef building corals.
抗生素常用于控制患病生物体内的微生物生长。然而，在早期发育阶段使用抗生素治疗会对发育和生理产生负面影响，从而抵消减少或消除病原体的积极影响。同样，抗生素会因对耐药菌和敏感菌的不同效果而改变微生物群落。尽管抗生素的应用通常不会导致海洋无脊椎动物死亡，但对于发育和转录效应知之甚少。这些亚致死效应可能会降低宿主生物的适应性，并在抗生素去除后导致负面变化。在这里，我们量化了抗生素处理对模式刺胞动物 发育、基因表达和可培养细菌群落的影响。
分别以 50 和 200 µg mL 的浓度比较氨苄青霉素、链霉素、利福平、和新霉素，以及以 50 µg mL 的浓度组合，以评估它们对 的影响。首先，我们确定了抗生素对幼虫发育的影响。接下来，使用扩增子 16S rDNA 基因测序来比较抗生素处理后持续存在的可培养细菌，以确定这些处理如何对原生微生物组产生差异选择。最后，我们确定了急性（3 天）和慢性（8 天）抗生素处理如何影响成年海葵的基因表达。
在大多数暴露条件下，随着抗生素浓度的增加，幼虫定居的时间延长，而联合处理的延迟时间最长为 3 天。可培养细菌在大多数暴露条件下持续存在，我们鉴定了 359 个扩增子序列变体 (ASV)。细菌的最大比例属于γ变形菌门，最常见的 ASV 被鉴定为 和 。急性抗生素暴露导致与表观遗传机制和神经过程相关的基因表达差异，而与对照组相比，持续应用导致伴侣蛋白上调和线粒体基因下调。基因本体论分析确定了两种抗生素处理后与发育和代谢相关的术语总体耗尽。
抗生素导致 幼虫的定居时间显著增加。抗生素处理后的可培养细菌种类具有丰富的分类学多样性。此外，抗生素的转录效应及其去除后会导致基因表达的显著差异，这可能会影响海葵的生理学，包括细菌对海葵基因表达的信号去除。我们的研究表明，抗生素的影响超出了减少细菌的范围，在将抗生素应用于包括造礁珊瑚在内的水生无脊椎动物时，可能需要考虑这些影响。
