Thermal acclimation alters both basal heat shock protein gene expression and the heat shock response in juvenile lake whitefish (Coregonus clupeaformis).

Long-term temperature shifts associated with seasonal variability are common in temperate regions. However, these natural shifts could place significant strain on thermal stress responses of fishes when combined with mean increases in water temperatures predicted by climate change models. We examined the relationship between thermal acclimation, basal expression of heat shock protein (hsp) genes and the activation of the heat shock response (HSR) in lake whitefish (LWF; Coregonus clupeaformis), a cold water species of cultural and commercial significance.

Transcriptomics reveal core activities of the plant growth-promoting bacterium RAY209 during interaction with canola and soybean roots.

The plant growth-promoting rhizobacterium RAY209 is capable of establishing strong root attachment during early plant development at 7 days post-inoculation. The transcriptional response of RAY209 was measured using RNA-seq during early (day 2) and sustained (day 7) root colonization of canola plants, capturing RAY209 differentiation from a medium-suspended cell state to a strongly root-attached cell state. Transcriptomic data was collected in an identical manner during RAY209 interaction with soybean roots to explore the putative root colonization response to this globally relevant crop.

Lamprey metamorphosis: Thyroid hormone signaling in a basal vertebrate.

As one of the most basal living vertebrates, lampreys represent an excellent model system to study the evolution of thyroid hormone (TH) signaling. The lamprey hypothalamic-pituitary-thyroid and reproductive axes overlap functionally. Lampreys have 3 gonadotropin-releasing hormones and a single glycoprotein hormone from the hypothalamus and pituitary, respectively, that regulate both the reproductive and thyroid axes.

CRH peptide evolution occurred in three phases: Evidence from characterizing sea lamprey CRH system members.

The corticotropin releasing hormone (CRH) system, which includes the CRH family of peptides, their receptors (CRHRs) and a binding protein (CRHBP), has been strongly conserved throughout vertebrate evolution. The identification of invertebrate homologues suggests this system evolved over 500 million years ago. However, the early vertebrate evolution of the CRH system is not understood.

Thermal stress and the heat shock response in embryonic and young of the year juvenile lake whitefish.

We investigated the effects of thermal stress on embryonic (fin flutter, vitelline circulation stage) and young of the year (YOY) juvenile lake whitefish by characterizing the kinetics of the heat shock response (HSR). Lake whitefish were subjected to one of three different heat shock (HS) temperatures (3, 6, or 9 °C above control) for six different lengths of time (0.25, 0.

Thyroid hormone and retinoid X receptor function and expression during sea lamprey (Petromyzon marinus) metamorphosis.

Sea lampreys (Petromyzon marinus) are members of the ancient class Agnatha and undergo a metamorphosis that transforms blind, sedentary, filter-feeding larvae into free-swimming, parasitic juveniles. Thyroid hormones (THs) appear to be important for lamprey metamorphosis, however, serum TH concentrations are elevated in the larval phase, decline rapidly during early metamorphosis and remain low until metamorphosis is complete; these TH fluctuations are contrary to those of other metamorphosing vertebrates. Moreover, thyroid hormone synthesis inhibitors (goitrogens) induce precocious metamorphosis and exogenous TH treatments disrupt natural metamorphosis in P.

Thyroid hormone deiodinase type 2 mRNA levels in sea lamprey (Petromyzon marinus) are regulated during metamorphosis and in response to a thyroid challenge.

Thyroid hormones (THs) are crucial for normal vertebrate development and are the one obligate morphogen that drives amphibian metamorphosis. However, contrary to other metamorphosing vertebrates, lampreys exhibit a sharp drop in serum TH early in metamorphosis, and anti-thyroid agents such as potassium perchlorate (KClO(4)) induce metamorphosis. The type 2 deiodinase (D2) enzyme is a key regulator of TH availability during amphibian metamorphosis.

Molecular cloning, tissue distribution, and developmental expression of lamprey transthyretins.

We isolated and cloned full-length cDNAs of transthyretin (TTR) from 2 genera of lamprey, Petromyzon marinus and Lampetra appendix. These sequences represent the first report of TTR sequences in vertebrates basal to teleost fishes. The deduced amino acid sequence of lamprey TTR cDNAs showed 36-47% identity with those from other vertebrates; secondary structure predictions and homology-based modeling were both consistent with TTRs from other vertebrates, and these cDNAs lacked the signatures found in TTR-like sequences of non-vertebrates.

Cloning of a functional vitamin D receptor from the lamprey (Petromyzon marinus), an ancient vertebrate lacking a calcified skeleton and teeth.

The nuclear vitamin D receptor (VDR) mediates the actions of its 1,25-dihydroxyvitamin D(3) ligand to control gene expression in terrestrial vertebrates. Prominent functions of VDR-regulated genes are to promote intestinal absorption of calcium and phosphate for bone mineralization and to potentiate the hair cycle in mammals. We report the cloning of VDR from Petromyzon marinus, an unexpected finding because lampreys lack mineralized tissues and hair.

Analysis of lamprey and hagfish genes reveals a complex history of gene duplications during early vertebrate evolution.

It has been proposed that two events of duplication of the entire genome occurred early in vertebrate history (2R hypothesis). Several phylogenetic studies with a few gene families (mostly Hox genes and proteins from the MHC) have tried to confirm these polyploidization events. However, data from a single locus cannot explain the evolutionary history of a complete genome.

The role of prolactin in fish osmoregulation: a review.

The protein hormone prolactin (PRL) was first discovered as an anterior pituitary factor capable of stimulating milk production in mammals. We now know that PRL has over 300 different functions in vertebrates. In fish, PRL plays an important role in freshwater osmoregulation by preventing both the loss of ions and the uptake of water.