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1. Impact of pollen-feeding on egg-laying and cyanogenic glucoside abundance in red postman butterflies

   https://doi.org/10.24072/pci.evolbiol.100648  

   Briscoe, Adriana (August 2023, Peer Community in Evolutionary Biology)

   Growth, development and reproduction in animals are all limited by dietary nutrients. Expansion of an organism’s diet to sources not accessible to closely related species reduces food competition, and eases the constraints of nutrient limited diets. Adult butterflies are herbivorous insects known to feed primarily on nectar from flowers, which is rich in sugars but poor in amino acids. Only certain species in the genus Heliconius are known to also feed on pollen, which is especially rich in amino acids, and is known to prolong their lives by several months. The ability to digest pollen in Heliconius has been linked to specialized feeding behaviors (Krenn et al. 2009) and extra-oral digestion using enzymes, possibly including duplicated copies of cocoonase (Harpel et al. 2016; Smith et al. 2016 and 2018), a protease used by some moths to digest silk upon eclosion from their cocoons. In this reprint, Pinheiro de Castro and colleagues investigated the impact of artificial and natural diets on egg-laying ability, body weight, and cyanogenic glucoside abundance in adult Heliconius erato butterflies of both sexes. 

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2. Tuning Encodable Tetrazine Chemistry for Site-Specific Protein Bioorthogonal Ligations

   https://doi.org/10.1101/2025.05.20.655094  

   Jana, Subhashis; Eddins, Alex J; Gangarde, Yogesh M; Karplus, P Andrew; Mehl, Ryan A (May 2025, bioRxiv)

   Abstract Using genetic code expansion (GCE) to encode bioorthogonal chemistry has emerged as a promising method for protein labeling, both in vitro and within cells. Here, we demonstrate that tetrazine amino acids incorporated into proteins are highly tunable and have extraordinary potential for fast and quantitative bioorthogonal ligations. We describe the synthesis and characterize reaction rates of 29 tetrazine amino acids (20 of which are new) and compare their encoding ability into proteins using evolved Tet ncAA encoding tRNA/RS pairs. For these systems, we characterized on-protein Tet stability, reaction rates, and ligation extents, as the utility of a bioorthogonal labeling group depends on its stability and reactivity when encoded into proteins. By integrating data on encoding efficiency, selectivity, on-protein stability, and in-cell labeling for Tet tRNA/RS pairs, we developed the smallest, fastest, and most stable Tet system to date. This was achieved by introducing fluorine substituents to Tet4, resulting in reaction rates at the 10⁶ M⁻¹s⁻¹ level while minimizing degradation. This study expands the toolbox of bioorthogonal reagents for Tet-sTCO-based, site-specific protein labeling and demonstrates that the Tet-ncAA is a uniquely tunable, highly reactive, and encodable bioorthogonal functional group. These findings provide a foundation to further explore Tet-ncAA encoding and reactivity. 

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3. The common house spider, Parasteatoda tepidariorum, maintains silk gene expression on sub-optimal diet

   https://doi.org/10.1371/journal.pone.0237286  

   Miller, Jeremy; Vienneau-Hathaway, Jannelle; Dendev, Enkhbileg; Lan, Merrina; Ayoub, Nadia A. (December 2020, PLOS ONE)

   Signore, Giovanni (Ed.)

   Cobweb weaving spiders and their relatives spin multiple task-specific fiber types. The unique material properties of each silk type result from differences in amino acid sequence and structure of their component proteins, primarily spidroins (spider fibrous proteins). Amino acid content and gene expression measurements of spider silks suggest some spiders change expression patterns of individual protein components in response to environmental cues. We quantified mRNA abundance of three spidroin encoding genes involved in prey capture in the common house spider, Parasteatoda tepidariorum (Theridiidae), fed different diets. After 10 days of acclimation to the lab on a diet of mealworms, spiders were split into three groups: (1) individuals were immediately dissected, (2) spiders were fed high-energy crickets, or (3) spiders were fed low-energy flies, for 1 month. All spiders gained mass during the acclimation period and cricket-fed spiders continued to gain mass, while fly-fed spiders either maintained or lost mass. Using quantitative PCR, we found no significant differences in the absolute or relative abundance of dragline gene transcripts, major ampullate spidroin 1 ( MaSp1 ) and major ampullate spidroin 2 ( MaSp2 ), among groups. In contrast, prey-wrapping minor ampullate spidroin ( MiSp) gene transcripts were significantly less abundant in fly-fed than lab-acclimated spiders. However, when measured relative to Actin , cricket-fed spiders showed the lowest expression of MiSp . Our results suggest that house spiders are able to maintain silk production, even in the face of a low-quality diet. 

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4. Amino acid and protein specificity of protein fatty acylation in Caenorhabditis elegans

   https://doi.org/10.1073/pnas.2307515121  

   Zhang, Bingsen; Yu, Yan; Fox, Bennett W; Liu, Yinong; Thirumalaikumar, Venkatesh P; Skirycz, Aleksandra; Lin, Hening; Schroeder, Frank C (January 2024, Proceedings of the National Academy of Sciences)

   Protein lipidation plays critical roles in regulating protein function and localization. However, the chemical diversity and specificity of fatty acyl group utilization have not been investigated using untargeted approaches, and it is unclear to what extent structures and biosynthetic origins ofS-acyl moieties differ fromN- andO-fatty acylation. Here, we show that fatty acylation patterns inCaenorhabditis elegansdiffer markedly between different amino acid residues. Hydroxylamine capture revealed predominant cysteineS-acylation with 15-methylhexadecanoic acid (isoC17:0), a monomethyl branched-chain fatty acid (mmBCFA) derived from endogenous leucine catabolism. In contrast, enzymatic protein hydrolysis showed that N-terminal glycine was acylated almost exclusively with straight-chain myristic acid, whereas lysine was acylated preferentially with two different mmBCFAs and serine was acylated promiscuously with a broad range of fatty acids, including eicosapentaenoic acid. Global profiling of fatty acylated proteins using a set of click chemistry–capable alkyne probes for branched- and straight-chain fatty acids uncovered 1,013S-acylated proteins and 510 hydroxylamine-resistantN- orO-acylated proteins. Subsets ofS-acylated proteins were labeled almost exclusively by either a branched-chain or a straight-chain probe, demonstrating acylation specificity at the protein level. Acylation specificity was confirmed for selected examples, including theS-acyltransferase DHHC-10. Last, homology searches for the identified acylated proteins revealed a high degree of conservation of acylation site patterns across metazoa. Our results show that protein fatty acylation patterns integrate distinct branches of lipid metabolism in a residue- and protein-specific manner, providing a basis for mechanistic studies at both the amino acid and protein levels. 

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5. Sex-specific plasticity and the nutritional geometry of insulin-signaling gene expression in Drosophila melanogaster

   https://doi.org/10.1186/s13227-021-00175-0  

   McDonald, Jeanne M. C.; Nabili, Pegah; Thorsen, Lily; Jeon, Sohee; Shingleton, Alexander W. (May 2021, EvoDevo)

   Abstract BackgroundSexual-size dimorphism (SSD) is replete among animals, but while the selective pressures that drive the evolution of SSD have been well studied, the developmental mechanisms upon which these pressures act are poorly understood. Ours and others’ research has shown that SSD inD. melanogasterreflects elevated levels of nutritional plasticity in females versus males, such that SSD increases with dietary intake and body size, a phenomenon called sex-specific plasticity (SSP). Additional data indicate that while body size in both sexes responds to variation in protein level, only female body size is sensitive to variation in carbohydrate level. Here, we explore whether these difference in sensitivity at the morphological level are reflected by differences in how the insulin/IGF-signaling (IIS) and TOR-signaling pathways respond to changes in carbohydrates and proteins in females versus males, using a nutritional geometry approach. ResultsThe IIS-regulated transcripts of4E-BPandInRmost strongly correlated with body size in females and males, respectively, but neither responded to carbohydrate level and so could not explain the sex-specific response to body size to dietary carbohydrate. Transcripts regulated by TOR-signaling did, however, respond to dietary carbohydrate in a sex-specific manner. In females, expression ofdILP5positively correlated with body size, while expression ofdILP2,3and8,was elevated on diets with a low concentration of both carbohydrate and protein. In contrast, we detected lower levels of dILP2 and 5 protein in the brains of females fed on low concentration diets. We could not detect any effect of diet ondILPexpression in males. ConclusionAlthough females and males show sex-specific transcriptional responses to changes in protein and carbohydrate, the patterns of expression do not support a simple model of the regulation of body-size SSP by either insulin- or TOR-signaling. The data also indicate a complex relationship between carbohydrate and protein level,dILPexpression and dILP peptide levels in the brain. In general, diet quality and sex both affect the transcriptional response to changes in diet quantity, and so should be considered in future studies that explore the effect of nutrition on body size. 

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