Household level multidimensional energy poverty and its determinants: Evidence from tea estates in Bangladesh.

Many eukaryotic lineages rely on acquisitions of metabolic capacity from other species to meet their energetic and material needs (). These expansions of metabolism can affect an organism’s contemporary ecology (e.g., by supporting the broadening of the metabolic niche) and may also affect evolutionary trajectories (e.g., by promoting coevolution or by supporting adaptive radiations) (, ). Acquisitions may occur through a variety of mechanisms, including the intracellular integration of endosymbiotic cells (as in coral-dinoflagellate, -, and - symbioses), or by stealing and retaining functional organelles (which occurs in both protistan systems such as ciliates and dinoflagellates and in animals such as the sea slugs and flatworms). However, it remains unclear how the integration of novel metabolic machinery into a new host cell alters the function of the host cell’s genome, especially in terms of metabolic regulation. Major changes in host transcription should reveal instances of dependencies upon foreign metabolic pathways and shed light on early events in the integration of foreign organelles before genetic integration. Kleptoplasty, or the trophic acquisition of functional chloroplasts, is one example of a metabolic acquisition with profound consequences for cellular physiology (). Organisms that transiently obtain the capacity for photosynthesis in this manner are able to expand their metabolic repertoire for energy and carbon acquisition. However, they must also modify their phagocytic pathways, tolerate photooxidative stress from light-harvesting machinery, and control the degradation of kleptoplastids. Nevertheless, dozens of lineages from diverse taxa, including Ciliata, Dinoflagellata, Cryptista, Discoba, Platyhelminthes, Mollusca, and Foraminifera, have evolved this capacity (–), supporting anywhere from 5 to 95% of their cellular carbon demands via acquired chloroplasts (). The effects of these acquisitions on host genomes remain unclear, in part because strategies for metabolic integration are as diverse as the plastid-acquiring lineages themselves. In some cases, this is supported by genes from either the current kleptoplast lineage or from lost ancestral plastids that have subsequently been horizontally integrated into the host nucleus (, –). In other cases, hosts retain transcriptionally active prey nuclei alongside chloroplasts (–), and these nuclei continue to regulate plastid function in the new host (, ).