Oxidative Phosphorylation Is Required for Powering Motility and Development of the Sleeping Sickness Parasite Trypanosoma brucei in the Tsetse Fly Vector

Comparative transcriptomic and metabolomics analysis of ovary in Nilaparvata lugens after trehalase inhibition

The fecundity of Nilaparvata lugens (brown planthopper) is influenced by trehalase (TRE). To investigate the mechanism by which trehalose affects the reproduction of N. lugens, we conducted a comparative transcriptomic and metabolomic analysis of the ovaries of N. lugens following injection with dsTREs and validamycin (a TRE inhibitor). The results revealed that 844 differentially expressed genes (DEGs) were identified between the dsGFP and dsTREs injection groups, with 317 up-regulated genes and 527 down-regulated genes. Additionally, 1451 DEGs were identified between the water and validamycin injection groups, with 637 up-regulated genes and 814 down-regulated genes. The total number of DEGs identified between the two comparison groups was 236. The overlapping DEGs were implicated in various biological processes, including protein metabolism, fatty acid metabolism, AMPK signaling, mTOR signaling, insulin/insulin-like growth factor signaling (IIS), the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and the cellular process of meiosis in oocytes. These results suggest that the inhibition of TRE expression may lead to alterations in ovarian nutrient and energy metabolism by modulating glucose transport and affecting amino acid metabolic pathways. These alterations may influence the reproduction of N. lugens by modulating reproductive regulatory signals. These findings provide robust evidence supporting the mechanism through which trehalase inhibition reduces the reproductive capacity of N. lugens.

How mitochondria showcase evolutionary mechanisms and the importance of oxygen

Darwinian evolution can be simply stated: natural selection of inherited variations increasing differential reproduction. However, formulated thus, links with biochemistry, cell biology, ecology, and population dynamics remain unclear. To understand interactive contributions of chance and selection, higher levels of biological organization (e.g., endosymbiosis), complexities of competing selection forces, and emerging biological novelties (such as eukaryotes or meiotic sex), we must analyze actual examples. Focusing on mitochondria, I will illuminate how biology makes sense of life's evolution, and the concepts involved. First, looking at the bacterium - mitochondrion transition: merging with an archaeon, it lost its independence, but played a decisive role in eukaryogenesis, as an extremely efficient aerobic ATP generator and internal ROS source. Second, surveying later mitochondrion adaptations and diversifications illustrates concepts such as constructive neutral evolution, dynamic interactions between endosymbionts and hosts, the contingency of life histories, and metabolic reprogramming. Without oxygen, mitochondria disappear; with (intermittent) oxygen diversification occurs in highly complex ways, especially upon (temporary) phototrophic substrate supply. These expositions show the Darwinian model to be a highly fruitful paradigm.

Mitochondrial adaptations throughout the Trypanosoma brucei life cycle

The unicellular parasite Trypanosoma brucei has a digenetic life cycle that alternates between a mammalian host and an insect vector. During programmed development, this extracellular parasite encounters strikingly different environments that determine its energy metabolism. Functioning as a bioenergetic, biosynthetic, and signaling center, the single mitochondrion of T. brucei is drastically remodeled to support the dynamic cellular demands of the parasite. This manuscript will provide an up-to-date overview of how the distinct T. brucei developmental stages differ in their mitochondrial metabolic and bioenergetic pathways, with a focus on the electron transport chain, proline oxidation, TCA cycle, acetate production, and ATP generation. Although mitochondrial metabolic rewiring has always been simply viewed as a consequence of the differentiation process, the possibility that certain mitochondrial activities reinforce parasite differentiation will be explored.