A Novel Molecular Solution for Ultraviolet Light Detection in Caenorhabditis elegans

For many organisms the ability to transduce light into cellular signals is crucial for survival. Light stimulates DNA repair and metabolism changes in bacteria, avoidance responses in single-cell organisms, attraction responses in plants, and both visual and nonvisual perception in animals. Despite these widely differing responses, in all of nature there are only six known families of proteins that can transduce light. Although the roundworm Caenorhabditis elegans has none of the known light transduction systems, we show here that C. elegans strongly accelerates its locomotion in response to blue or shorter wavelengths of light, with maximal responsiveness to ultraviolet light. Our data suggest that C. elegans uses this light response to escape the lethal doses of sunlight that permeate its habitat. Short-wavelength light drives locomotion by bypassing two critical signals, cyclic adenosine monophosphate (cAMP) and diacylglycerol (DAG), that neurons use to shape and control behaviors. C. elegans mutants lacking these signals are paralyzed and unresponsive to harsh physical stimuli in ambient light, but short-wavelength light rapidly rescues their paralysis and restores normal levels of coordinated locomotion. This light response is mediated by LITE-1, a novel ultraviolet light receptor that acts in neurons and is a member of the invertebrate Gustatory receptor (Gr) family. Heterologous expression of the receptor in muscle cells is sufficient to confer light responsiveness on cells that are normally unresponsive to light. Our results reveal a novel molecular solution for ultraviolet light detection and an unusual sensory modality in C. elegans that is unlike any previously described light response in any organism

Effect of host genotype and Eimeria acervulina infection on the metabolome of meat-type chickens.

OBJECTIVE:A study was conducted to identify metabolic biochemical differences between two chicken genotypes infected with Eimeria acervulina and to ascertain the underlying mechanisms for these metabolic alterations and to further delineate genotype-specific effects during merozoite formation and oocyst shedding. METHODS:Fourteen day old chicks of an unimproved (ACRB) and improved (COBB) genotype were orally infected with 2.5 x 105 sporulated E. acervulina oocysts. At 4 and 6 day-post infection, 5 birds from each treatment group and their controls were bled for serum. Global metabolomic profiles were assessed using ultra performance liquid chromatography/tandem mass spectrometry (metabolon, Inc.,). Statistical analyses were based on analysis of variance to identify which biochemicals differed significantly between experimental groups. Pathway enrichment analysis was conducted to identify significant pathways associated with response to E. acervulina infection. RESULTS:A total of 752 metabolites were identified across genotype, treatment and time post infection. Altered fatty acid (FA) metabolism and β-oxidation were identified as dominant metabolic signatures associated with E. acervulina infection. Key metabolite changes in FA metabolism included stearoylcarnitine, palmitoylcarnitine and linoleoylcarnitine. The infection induced changes in nucleotide metabolism and elicited inflammatory reaction as evidenced by changes in thromboxane B2, 12-HHTrE and itaconate. CONCLUSIONS:Serum metabolome of two chicken genotypes infected with E. acervulina demonstrated significant changes that were treatment-, time post-infection- and genotype-dependent. Distinct metabolic signatures were identified in fatty acid, nucleotide, inflammation and oxidative stress biochemicals. Significant microbial associated product alterations are likely to be associated with malabsorption of nutrients during infection

Heat Stress Alters the Effect of <i>Eimeria maxima</i> Infection on Ileal Amino Acids Digestibility and Transporters Expression in Meat-Type Chickens

Eimeria (E.) maxima invades the midgut of chickens and destroys the intestinal mucosa, impacting nutrient digestibility and absorption. Heat stress (HS) commonly affects the broiler chicken and contributes to inflammation and oxidative stress. We examined the independent and combined effects of HS and E. maxima infection on apparent amino acid ileal digestibility (AID) and mRNA expression of amino acid transporters in broiler chickens (Ross 708). There were four treatment groups: thermoneutral-control (TNc) and infected (TNi), heat-stress control (HSc) and infected (HSi), six replicates of 10 birds/treatment. Ileal content and tissue were sampled at 6 d post infection to determine AID and transporters expression. Surprisingly, the HSi chickens exposed to two critical stressors exhibited normal AID. Only the TNi group displayed reduction in AID. Using TNc as control, the HSc group showed upregulated CAT1, LAT4, TAT1, SNAT1, and SNAT7. The HSi group showed upregulated CAT1 and LAT1, and downregulated b0,+AT, rBAT, SNAT1, and SNAT2. The TNi group showed upregulated CAT1, LAT1, and SNAT1 and downregulated B0AT1, b0,+AT, rBAT, LAT4, and TAT1. The expression of all enterocytic-apical and about half of the basolateral transporters was higher in the HSi group than in the TNi group, indicating that HS can putatively alleviate the E. maxima adverse effect on ileal digestion and absorption

Host transcriptome response to heat stress and Eimeria maxima infection in meat-type chickens.

Eimeria (E.) maxima parasite infects chickens' midgut disrupting the jejunal and ileal mucosa causing high morbidity and mortality. Heat stress (HS) is a seasonal stressor that impacts biological functions leading to poor performance. This study elucidates how HS, E. maxima infection, and their combination affect the ileum transcriptome. Two-hundred and forty 2-week-old males Ross708 chickens were randomly allocated into four treatment groups: thermoneutral-control (TNc), thermoneutral-infected (TNi), heat-stress control (HSc), and heat stress-infected (HSi), with 6 replicates each of 10 birds. Infected groups received 200x103 sporulated E. maxima oocysts/bird, and heat-treated groups were raised at 35°C. At 6-day post-treatment, ileums of five randomly selected chickens per group were sampled, RNA was extracted and sequenced. A total of 413, 3377, 1908, and 2304 DEGs were identified when applying the comparisons: TNc vs HSc, TNc vs TNi, HSi vs HSc, and TNi vs HSi, respectively, at cutoff ≥1.2-fold change (FDR: q<0.05). HSc vs TNc showed upregulation of lipid metabolic pathways and degradation/metabolism of multiple amino acids; and downregulation of most immune-related and protein synthesis pathways. TNc vs TNi displayed upregulation of most of immune-associated pathways and eukaryotic mRNA maturation pathways; and downregulation of fatty acid metabolism and multiple amino acid metabolism pathways including tryptophan. Comparing HSi versus HSc and TNi revealed that combining the two stressors restored the expression of some cellular functions, e.g., oxidative phosphorylation and protein synthesis; and downregulate immune response pathways associated with E. maxima infection. During E. maxima infection under HS the calcium signaling pathway was downregulated, including genes responsible for increasing the cytoplasmic calcium concentration; and tryptophan metabolism was upregulated, including genes that contribute to catabolizing tryptophan through serotonin and indole pathways; which might result in reducing the cytoplasmic pool of nutrients and calcium available for the parasite to scavenge and consequently might affect the parasite's reproductive ability

Glucose Supplementation Improves Performance and Alters Glucose Transporters’ Expression in <i>Pectoralis major</i> of Heat-Stressed Chickens

Glucose level in birds’ tissue decreases due to heat stress (HS)-induced reduction in feed intake (FI); impairing metabolism and growth. The effect of glucose supplementation on the performance of broiler chickens was evaluated under thermoneutral (TN) and HS conditions. Glucose was supplemented at 0 and 6% under TN-(25 °C) and HS-(25 °C–35 °C–25 °C) conditions. The treatments were TN + 0%-glucose (TN0); TN + 6%-glucose (TN6), HS + 0%-glucose (HS0) and HS + 6%-glucose (HS6). There were 6 replicates (19 birds each)/treatment. Heat and glucose supplementation were applied from d28–35. At d35, Pectoralis (P.) major was sampled from one bird/replicate to determine glucose transporters’ mRNA expression. Heat application lowered (p P. major- and drumstick-yield reduced (p P. major yield by 14%. Glucose supplementation increased SGLT1 expression with/without heat treatment while HS independently increased the expression of GLUT 1, 5 and 10. Glucose supplementation under HS could improve performance of broilers

Effect of Glucose Supplementation on Apoptosis in the <i>Pectoralis major</i> of Chickens Raised under Thermoneutral or Heat Stress Environment

Reduced feed intake during heat stress (HS) disrupts glucose homeostasis, thereby resulting in endoplasmic reticulum (ER) stress and triggering apoptosis in chickens. We hypothesize that glucose supplementation could reduce apoptosis in chickens raised under HS. This study comprised 456 28-day-old broiler chickens randomly assigned to four treatment combinations under glucose supplementation and HS. The treatments were TN0, TN6, HS0, and HS6 with two glucose levels (0% and 6%) and two temperature levels (25 °C (thermoneutral-TN) and 35 °C (8.00 AM to 8.00 PM, (HS)). After 7 days post-HS, the blood glucose level for the HS6 group was higher than for TN0, TN6, and HS0. We studied the mRNA expression of genes and caspase-3 activity in the four experimental groups. The expressions of GCN2, ATF4, CHOP, and FOXO3a increased during HS regardless of glucose supplementation, while PERK and MAFbx increased only under HS with glucose supplementation. We show that under TN conditions, glucose supplementation led to a significant increase in cellular apoptosis in the Pectoralis (P.) major. However, under HS with glucose, the level of apoptosis was similar to that of chickens raised under TN conditions with no glucose supplementation. The utility of glucose to curtail apoptosis under HS should be tested under other intense models of HS

S1 Fig -

Genes’ expression level measured by RT-qPCR compared with the fold change produced using Hi-Seq data for the chickens exposed to HS (HSc) compared to their thermoneutral control (TNc) at 6 day-post-treatment (TNc vs. HSc) (A), and the correlation test shows the correlation coefficient (r) of the expression values produced by either method (B). Taking the expression values of the TNc as the control for the relative expression of the HSc group the expression values of the TNc group to 1 (Livak’s method). Error bars depict the SEM. (ZIP)</p

S4 Fig -

Genes’ expression level measured by RT-qPCR compared with the fold change produced using Hi-Seq data for the chickens infected with Eimeria maxima raised either under HS (HSi) or thermoneutral condition (TNi) at 6 day-post-treatment (TNi vs. HSi) (A), and the correlation test shows the correlation coefficient (r) of the expression values produced by either method (B). Taking the expression values of the TNi as the control for the relative expression of the HSi group brought the expression values of the TNi group to 1 (Livak’s method). Error bars depict the SEM. (ZIP)</p

Number of DEGs of each pairwise comparison at 6 dpi of chickens infected with <i>Eimeria maxima</i> and their uninfected controls that are raised in a thermoneutral or heat stress environment: TNc = thermoneutral control, TNi = thermoneutral infected, HSc = heat stress control, HSi = heat stress infected.

Number of DEGs of each pairwise comparison at 6 dpi of chickens infected with Eimeria maxima and their uninfected controls that are raised in a thermoneutral or heat stress environment: TNc = thermoneutral control, TNi = thermoneutral infected, HSc = heat stress control, HSi = heat stress infected.</p

Fig 3 -

A. Heatmap of the top ~60 DEGs of TNc vs. TNi, as Log 2 relative hit counts of the comparison between the chickens infected with Eimeria maxima (TNi) and their uninfected thermoneutral control (TNc) at 6 day-post-treatment. B. The top KEGG pathways of TNc vs. TNi, based on the pathway term significance (α≤0.1) of the comparison between the chickens infected with Eimeria maxima (TNi) and their uninfected thermoneutral control (TNc) at 6 day-post-treatment. The green squares and arrowheads depict the downregulated pathways and genes, respectively. The red circles and arrowheads depict the upregulated pathways and genes, respectively. The bigger size squares and circles denote the lower p-value. An increase in the color transparency (lighter color) of the squares and circles indicates an increase in the percentage of the included genes with expression that counter the regulation direction of the pathway. C. The top significant KEGG pathways of TNc vs. TNi, the comparison between the chickens infected with Eimeria maxima (TNi) and their uninfected thermoneutral control (TNc) at 6 day-post-treatment. D. The top significant Gene Ontology terms of TNc vs. TNi, the comparison between the chickens infected with Eimeria maxima (TNi) and their uninfected thermoneutral control (TNc) at 6 day-post-treatment.</p