Flavobacterium oreochromis has been associated with elevated mortality rates during the early stages of tambaqui (Colossoma macropomum) aquaculture. This study investigated genetic responses to bacter Show more
Flavobacterium oreochromis has been associated with elevated mortality rates during the early stages of tambaqui (Colossoma macropomum) aquaculture. This study investigated genetic responses to bacterial infection in juvenile fish by comparing gene expression profiles between symptomatic (IS) and asymptomatic (IA) individuals. Skin samples from both IA and IS individuals were collected for transcriptome sequencing. Approximately 21 million reads per library were aligned to the tambaqui genome. Differential expression analysis revealed 2,176 upregulated and 1,219 downregulated genes in IS individuals, whereas 1,358 genes were upregulated and 488 downregulated in IA individuals. Notably, genes upregulated in both groups were associated with autophagy (e.g., atg4b and ulk2) and oxidative stress responses (e.g., klf9 and txnip). In contrast, genes related to tissue integrity, such as unc45b and akap6, were consistently downregulated during infection. These results suggest a dual host response to F. oreochromis infection, characterized by activation of cellular stress pathways and the suppression of genes involved in maintaining structural integrity. The upregulation of autophagy-related (atg4b, ulk2) and oxidative stress-regulating (klf9 and txnip) genes likely reflects an attempt by the host to counteract bacterial invasion through enhanced intracellular degradation and redox homeostasis. Conversely, the downregulation of unc45b and akap6 may indicate a compromise in structural defense mechanisms. These findings offer valuable insights into the immunogenetics of tambaqui and have direct implications for enhancing disease resistance in aquaculture. Moreover, they contribute to a better understanding of the complex interplay between molecular pathways involved in F. oreochromis infection. Show less
A few species have evolved multiple sex chromosome systems with more than two Xs or Ys due to sex chromosome-autosome translocations. Among vertebrates, frogs (Anura) have the highest known number of Show more
A few species have evolved multiple sex chromosome systems with more than two Xs or Ys due to sex chromosome-autosome translocations. Among vertebrates, frogs (Anura) have the highest known number of such neo-sex chromosome systems, making them interesting for studying how such systems evolve. In this work, we investigated two Leptodactylus species, L. pentadactylus (LPE) and L. paraensis (LPA), with large ring multivalents in male meiosis, using genomic and cytogenetic investigation of repetitive DNA sequences, including satellite DNAs (satDNAs), and transposable elements (TEs). SatDNA mapping identify individual chromosomes in the LPE ring, and morphologies suggest that all chromosomes are shared with the LPA ring although a common ring origin is not firmly supported. In situ mapping suggests recent satDNA accumulation in subtelomeric regions since the split from the outgroups, likely unrelated to the translocations that created sex-linkage, which probably involved breaks in the pericentromeric regions. Show less