Carbon dioxide‐ and temperature‐mediated changes in plant defensive compounds alter food utilization of herbivores

Although the impact of elevated carbon dioxide and rising temperature on plants and animals has been extensively documented recently, only limited understanding exists regarding their combined effects. The objective of this research was to address the consequences of using combinations of elevated CO₂ and elevated temperature on a plant's defensive chemistry, and subsequent utilization of the plant as insect food. Our results indicated that elevated CO₂ and increased temperature, for the most part, act independently on the production of defensive compounds in broccoli leaves (Brassica oleracea L. var. italica). CO₂ concentrations had significant effects on the foliar water content, total phenolic compounds, polyphenol oxidase and trypsin inhibitor concentrations. The herbivore Spodoptera litura (Fabricius; Lepidoptera: Noctuidae) responded to changes in the plant secondary chemistry, with larvae consuming more plant materials that had been exposed to elevated CO₂. The food utilization efficiencies of second‐instar larvae were more sensitive to CO₂‐treated foliage than those of the third‐ and fourth‐instar larvae. Temperature did exert a significant effect on food utilization (ECD) by the larvae. Our study will provide important information in future predictions on plant–insect interactions as a result of climate change. The study also demonstrated that since various larval stages might respond differently to climate change, this possibility needs to be considered in future forecasting and monitoring.     

amoA-encoding archaea in wastewater treatment plants: a review

Recent evidence from natural environments suggests that in addition to ammonia-oxidizing bacteria, ammonia-oxidizing archaea (AOA) affiliated with Thaumarcheota, a new phylum of the domain Archaea, also oxidize ammonia to nitrite and thus participate in the global nitrogen cycle. Besides natural environments, modern data indicate the presence of amoA-encoding archaea (AEA) in wastewater treatment plants (WWTPs). To further elucidate whether AEA in WWTPs are AOA and to clarify the role of AEA in WWTPs, this paper reviews the current knowledge on this matter for wastewater engineers and people in related fields. The initial section coveys a microbiological point of view and is particularly based upon data from AOA cultures. The later section summarizes what is currently known about AEA in relation to WWTPs. Based on the reviewed data, future research pathways are proposed in an effort to further what is known about AEA in wastewater treatment systems.     

Incorporation of 13C-HCO3− by ammonia-oxidizing archaea and bacteria during ammonia oxidation of sludge from a municipal wastewater treatment plant

Applied Microbiology and Biotechnology - Ammonia-oxidizing archaea (AOA) have recently been proposed as potential players for ammonia removal in wastewater treatment plants (WWTPs). However, there...