Transcriptome analysis of neonatal larvae after hyperthermia-induced seizures in the contractile silkworm, Bombyx mori.

The ability to respond quickly and efficiently to transient extreme environmental conditions is an important property of all biota. However, the physiological basis of thermotolerance in different species is still unclear. Here, we found that the cot mutant showed a seizure phenotype including contraction of the body, rolling, vomiting gut juice and a momentary cessation of movement, and the heartbeat rhythm of the dorsal vessel significantly increases after hyperthermia. To comprehensively understand this process at the molecular level, the transcriptomic profile of cot mutant, which is a behavior mutant that exhibits a seizure phenotype, was investigated after hyperthermia (42°C) that was induced for 5 min. By digital gene expression profiling, we determined the gene expression profile of three strains (cot/cot ok/ok, +/+ ok/ok and +/+ +/+) under hyperthermia (42°C) and normal (25°C) conditions. A Venn diagram showed that the most common differentially expressed genes (DEGs, FDR<0.01 and log2 Ratio≥1) were up-regulated and annotated with the heat shock proteins (HSPs) in 3 strains after treatment with hyperthermia, suggesting that HSPs rapidly increased in response to high temperature; 110 unique DEGs, could be identified in the cot mutant after inducing hyperthermia when compared to the control strains. Of these 110 unique DEGs, 98.18% (108 genes) were up-regulated and 1.82% (two genes) were down-regulated in the cot mutant. KEGG pathways analysis of these unique DEGs suggested that the top three KEGG pathways were "Biotin metabolism," "Fatty acid biosynthesis" and "Purine metabolism," implying that diverse metabolic processes are active in cot mutant induced-hyperthermia. Unique DEGs of interest were mainly involved in the ubiquitin system, nicotinic acetylcholine receptor genes, cardiac excitation-contraction coupling or the Notch signaling pathway. Insights into hyperthermia-induced alterations in gene expression and related pathways could yield hints for understanding the relationship between behaviors and environmental stimuli (hyperthermia) in insects

Serotonin control of thermotaxis memory behavior in nematode Caenorhabditis elegans.

Caenorhabditis elegans is as an ideal model system for the study of mechanisms underlying learning and memory. In the present study, we employed C. elegans assay system of thermotaxis memory to investigate the possible role of serotonin neurotransmitter in memory control. Our data showed that both mutations of tph-1, bas-1, and cat-4 genes, required for serotonin synthesis, and mutations of mod-5 gene, encoding a serotonin reuptake transporter, resulted in deficits in thermotaxis memory behavior. Exogenous treatment with serotonin effectively recovered the deficits in thermotaxis memory of tph-1 and bas-1 mutants to the level of wild-type N2. Neuron-specific activity assay of TPH-1 suggests that serotonin might regulate the thermotaxis memory behavior by release from the ADF sensory neurons. Ablation of ADF sensory neurons by expressing a cell-death activator gene egl-1 decreased the thermotaxis memory, whereas activation of ADF neurons by expression of a constitutively active protein kinase C homologue (pkc-1(gf)) increased the thermotaxis memory and rescued the deficits in thermotaxis memory in tph-1 mutants. Moreover, serotonin released from the ADF sensory neurons might act through the G-protein-coupled serotonin receptors of SER-4 and SER-7 to regulate the thermotaxis memory behavior. Genetic analysis implies that serotonin might further target the insulin signaling pathway to regulate the thermotaxis memory behavior. Thus, our results suggest the possible crucial role of serotonin and ADF sensory neurons in thermotaxis memory control in C. elegans

(Table 2) Mineralogy, stable isotopes, and mineral percentages of the carbonate fraction of samples from the South China Sea

Chemoherm carbonates, as well as numerous other types of methane seep carbonates, were discovered in 2004 along the passive margin of the northern South China Sea. Lithologically, the carbonates are micritic containing peloids, clasts and clam fragments. Some are highly brecciated with aragonite layers of varying thicknesses lining fractures and voids. Dissolution and replacement is common. Mineralogically, the carbonates are dominated by high magnesium calcites (HMC) and aragonite. Some HMCs with MgCO3 contents of between 30–38 mol%–extreme-HMC, occur in association with minor amounts of dolomite. All of the carbonates are strongly depleted in d13C, with a range from -35.7 to -57.5 per mil PDB and enriched in d18O (+ 4.0 to + 5.3 per mil PDB). Abundant microbial rods and filaments were recognized within the carbonate matrix as well as aragonite cements, likely fossils of chemosynthetic microbes involved in carbonate formation. The microbial structures are intimately associated with mineral grains. Some carbonate mineral grains resemble microbes. The isotope characteristics, the fabrics, the microbial structure, and the mineralogies are diagnostic of carbonates derived from anaerobic oxidation of methane mediated by microbes. From the succession of HMCs, extreme-HMC, and dolomite in layered tubular carbonates, combined with the presence of microbial structure and diagenetic fabric, we suggest that extreme-HMC may eventually transform into dolomites. Our results add to the worldwide record of seep carbonates and establish for the first time the exact locations and seafloor morphology where such carbonates formed in the South China Sea. Characteristics of the complex fabric demonstrate how seep carbonates may be used as archives recording multiple fluid regimes, dissolution, and early transformation events

The heartbeat of <i>cot</i> mutants.

<p>(A) The transparent cuticle phenotype in <i>cot</i> mutants (<i>cot/cot ok/ok</i>) and controls (<i>+/+ ok/ok</i>). (B) The heartbeat of <i>cot/cot ok/ok</i> and <i>+/+ ok/ok</i> strains at room temperature and after 42°C for 3 min. Ten individuals were investigated for each genotype group with three replicates. BPM, beats per minute. Error bars indicate the SEM. Statistically significant differences were identified using Student's <i>t</i>-test; p<0.05.</p

Statistical analysis of transcriptome sequencing data.

<p>Statistical analysis of transcriptome sequencing data.</p

The <i>cot</i> mutant (<i>cot/cot ok/ok</i>) shows a temperature-induced seizure phenotype.

<p>(A) The seizure phenotype of <i>cot</i> mutants (<i>cot/cot ok/ok</i>) treated at 35°C for 10 min. (B) The behavioral response to hyperthermia in the <i>cot/cot ok/ok</i>, <i>+/+ ok/ok</i> and <i>+/+ +/+</i> strains. Seizures were defined as a period of body contact, followed by failure to maintain standing posture, with rolling, vomiting gut juice and occasional temporary absence of movement. Individuals at day 5 of the fifth instar (n = 15 per strain) were immersed in a temperature-controlled electrothermal incubator (35°C, 10 min). The status of individual flies was determined at 1 min intervals and the cumulative number of individuals with seizure was determined at each time point for each strain. Data are presented as the means ± SEM.</p

Common differentially expressed genes in 3 strains (<i>cot/cot ok</i>/<i>ok</i>, +/+ <i>ok</i>/<i>ok</i> and +/+ +/+) after treatment with hyperthermia (42°C).

<p>Note: Fold^a indicates the ratio of RPKM of <i>cot</i>/<i>cot ok</i>/<i>ok</i> (42°C) sample divided by the RPKM of <i>cot</i>/<i>cot ok</i>/<i>ok</i> (25°C) samples; Fold^b indicates the ratio of RPKM of <i>+/+ ok/ok</i> (42°C) sample divided by the RPKM of <i>+/+ ok/ok</i> (25°C) samples; Fold^c indicates the ratio of RPKM of <i>+/+ +/+</i> (42°C) sample divided by the RPKM of <i>+/+ +/+</i> (25°C) samples.</p><p>Common differentially expressed genes in 3 strains (<i>cot/cot ok</i>/<i>ok</i>, +/+ <i>ok</i>/<i>ok</i> and +/+ +/+) after treatment with hyperthermia (42°C).</p

The category of biological process for the unique DEGs in the <i>cot</i> strain after hyperthermia induction.

<p>DEGs (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113214#pone.0113214.s009" target="_blank">Table S4</a>) were broadly categorized according to their biological process. Numbers represent the actual number of DEGs.</p