Some like it hot: temperature and acidification modulate larval development and settlement of the sea urchin Arbacia lixula

We studied the effects of temperature and pH on larval development, settlement and juvenile survival of a Mediterranean population of the sea urchin Arbacia lixula. Three temperatures (16, 17.5 and 19 °C) were tested at present pH conditions (pHT 8.1). At 19 °C, two pH levels were compared to reflect present average (pHT 8.1) and near-future average conditions (pHT 7.7, expected by 2100). Larvae were reared for 52-days to achieve the full larval development and complete the metamorphosis to the settler stage. We analyzed larval survival, growth, morphology and settlement success. We also tested the carry-over effect of acidification on juvenile survival after 3 days. Our results showed that larval survival and size significantly increased with temperature. Acidification resulted in higher survival rates and developmental delay. Larval morphology was significantly altered by low temperatures, which led to narrower larvae with relatively shorter skeletal rods, but larval morphology was only marginally affected by acidification. No carry-over effects between larvae and juveniles were detected in early settler survival, though settlers from larvae reared at pH 7.7 were significantly smaller than their counterparts developed at pH 8.1. These results suggest an overall positive effect of environmental parameters related to global change on the reproduction of A. lixula, and reinforce the concerns about the increasing negative impact on shallow Mediterranean ecosystems of this post-glacial colonizer.

Dysménorrhée: patience, pilules ou bouillotte [Dysmenorrhea: patience, pills or hot-water bottle?].

Which treatments are used for dysmenorrhea and with what reported outcome? A questionnaire was sent to 2400 students and apprentices, following the "retrospective treatment-outcome" method. The response rate was 22%. Most frequent treatments used are ibuprofene (53%), paracetamol (51%), hormonal contraception (40%), hot-water bottle (or hot pad) (35%), food supplements or medicinal plants (23%). Physicians only discuss a tiny proportion of dysmenorrhea treatment in their consultation, because it is mostly a matter of self-treatment, with the family as the source of information in 80% of the cases. Rather surprising because not mentioned in most official guidelines, hot-water bottle (or hot pad) appears as the treatment followed by the best reported outcome (satisfactory in 92% of users).

Influence of environmental temperature and electrolyte balance on the performance of quails (Coturnix Coturnix Coturnix)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of temperature of incubation and type of growth medium on pigmentation in Serratia marcescens.

Maximal amounts of prodigiosin were synthesized in either minimal or complete medium after incubation of cultures at 27 C for 7 days. Biosynthesis of prodigiosin began earlier and the range of temperature for formation was greater in complete medium. No prodigiosin was formed in either medium when cultures were incubated at 38 C; however, after a shift to 27 C, pigmentation ensued, provided the period of incubation at 38 C was not longer than 36 hr for minimal medium or 48 hr for complete medium. Washed, nonpigmented cells grown in either medium at 38 C for 72 hr could synthesize prodigiosin when suspended in saline at 27 C when casein hydrolysate was added. These suspensions produced less prodigiosin at a slower rate than did cultures growing in casein hydrolysate at 27 C without prior incubation at 38 C. Optimal concentration of casein hydrolysate for pigment formation by suspensions was 0.4%; optimal temperature was 27 C. Anaerobic incubation, shift back to 38 C, killing cells by heating, or chloramphenicol (25 mug/ml) inhibited pigmentation. Suspensions of washed cells forming pigment reached pH 8.0 to 8.3 rapidly and maintained this pH throughout incubation for 7 days. Measurements of viable count and of protein, plus other data, indicated that cellular multiplication did not occur in suspensions of washed cells during pigment formation. By this procedure utilizing a shift down in temperature, biosynthesis of prodigiosin by washed cells could be separated from multiplication of bacteria.

Effects Of Sterilization Methods On The Physical, Chemical, And Biological Properties Of Silk Fibroin Membranes.

Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing and it must not jeopardize the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical, chemical, and biological characteristics of dense and porous silk fibroin membranes. Silk fibroin membranes were treated by several procedures: immersion in 70% ethanol solution, ultraviolet radiation, autoclave, ethylene oxide, and gamma radiation, and were analyzed by scanning electron microscopy, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, tensile strength and in vitro cytotoxicity to Chinese hamster ovary cells. The results indicated that the sterilization methods did not cause perceivable morphological changes in the membranes and the membranes were not toxic to cells. The sterilization methods that used organic solvent or an increased humidity and/or temperature (70% ethanol, autoclave, and ethylene oxide) increased the silk II content in the membranes: the dense membranes became more brittle, while the porous membranes showed increased strength at break. Membranes that underwent sterilization by UV and gamma radiation presented properties similar to the nonsterilized membranes, mainly for tensile strength and FTIR results.

The C-terminal Region Of The Human P23 Chaperone Modulates Its Structure And Function.

The p23 protein is a chaperone widely involved in protein homeostasis, well known as an Hsp90 co-chaperone since it also controls the Hsp90 chaperone cycle. Human p23 includes a β-sheet domain, responsible for interacting with Hsp90; and a charged C-terminal region whose function is not clear, but seems to be natively unfolded. p23 can undergo caspase-dependent proteolytic cleavage to form p19 (p231-142), which is involved in apoptosis, while p23 has anti-apoptotic activity. To better elucidate the function of the human p23 C-terminal region, we studied comparatively the full-length human p23 and three C-terminal truncation mutants: p23₁₋₁₁₇; p23₁₋₁₃₁ and p23₁₋₁₄₂. Our data indicate that p23 and p19 have distinct characteristics, whereas the other two truncations behave similarly, with some differences to p23 and p19. We found that part of the C-terminal region can fold in an α-helix conformation and slightly contributes to p23 thermal-stability, suggesting that the C-terminal interacts with the β-sheet domain. As a whole, our results suggest that the C-terminal region of p23 is critical for its structure-function relationship. A mechanism where the human p23 C-terminal region behaves as an activation/inhibition module for different p23 activities is proposed.

Thermoregulatory Efficiency is Increased after Heat Acclimation in Tropical Natives

To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40 +/- 0 degrees C and 45.1 +/- 0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32 +/- 5%) in comparison to the trunk (11 +/- 2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs` sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency. J Physiol Anthropol 29(1): 1-12, 2010 http://www.jstage.jst.go.jp/browse/jpa2 [DOI: 10.2114/jpa2.29.1]

Desensitization of thermal hyperemia in the skin is reproducible.

OBJECTIVE: Local heating increases skin blood flow SkBF (thermal hyperemia). In a previous study, we reported that a first local thermal stimulus could attenuate the hyperemic response to a second one applied later on the same skin spot, a phenomenon that we termed desensitization. However, other studies found no evidence for desensitization in similar conditions. The aim of the present work was to test whether it was related to differences in instrumentation. METHODS: Twenty-eight healthy young males were studied. Two pairs of heating chambers, one custom-made (our study) and one commercial (other groups), were affixed to forearm skin. SkBF was measured with single-point laser-Doppler flowmetry (LDF) (780nm) in one pair, and laser-Doppler imaging (LDI) (633nm) in the other. A temperature step from 34 to 41°C, was applied for 30minutes and repeated after two hours. RESULTS: During the second thermal challenge, the plateau SkBF was lower than during the first thermal and was observed with each of the four combinations of SkBF measurement techniques and heating equipment (p<0.05 for all conditions, range -9% to -16% of the initial value). CONCLUSION: Desensitization of thermal hyperemia is not specific to peculiar operating conditions.

Quantifying degradation rates of transmembrane receptor kinases.

Transmembrane receptor-kinases are widespread throughout eukaryotes and their activities are known to regulate all kinds of cellular responses in diverse organs and cell types. In order to guarantee the correct amplitude and duration of signals, receptor levels at the cellular surface need to be tightly controlled. The regulation of receptor degradation is the most direct way to achieve this and elaborate mechanisms are in place to control this process. Therefore, the rate of receptor degradation is a parameter of central importance for understanding the dynamics of a signal transduction cascade. Unfortunately, degradation of transmembrane receptors is a complicated multistep process that involves internalization from the plasma membrane, invagination into the lumen of endosomal compartments, and finally fusion with the vacuole for degradation by vacuolar proteases. Therefore, degradation should be measured in an as noninvasive way as possible, such as not to interfere with the complicated transport processes. Here, a method for minimally invasive, in vivo turn-over measurements in intact organs is provided. This technique was used for quantifying the turn-over rates of the Brassinosteroid receptor kinase BRI1 (BRASSINOSTEROID INSENSITIVE 1) in Arabidopsis thaliana root meristems. Pulse-chase expression of a fluorescently labeled BRI1 variant was used and its turn-over rate was determined by quantitative confocal microscopy. This method is well suited to measure turn-over of transmembrane kinases, but can evidently be extended to measure turn-over of any types of transmembrane proteins.

Well-differentiated papillary mesothelioma of the tunica vaginalis testis: imaging on Tc-99m heat-denatured red blood cell scintigraphy.

An 18-year-old man presented with a growing painless left scrotal mass. Sonography showed a hydrocele and a homogeneous, well-encapsulated left extratesticular mass with similar echogenicity as the normal testis, suggestive of a splenogonadal fusion. To substantiate the diagnosis, the patient underwent Tc-99m heat-denatured red blood cell scintigraphy showing normal physiological hyperactivity in the spleen but activity similar to the blood pool projecting on the upper part of the left testis. This made testicular splenic tissue less likely. The patient underwent resection and histopathology revealed a well-differentiated papillary mesothelioma. Inguinal orchidectomy was subsequently performed and the patient was free of recurrence at 18 months.

The effect of in vitro heating on the distribution of nuclear matrix polypeptides in HeLa cells.

The in situ nuclear matrix was obtained from HeLa cells. After permeabilization with nonionic detergent, the resulting structures were incubated for 1 h at 37 degrees C to determine whether or not such an incubation might result in the redistribution of nuclear polypeptides which resisted extraction with buffers of high-ionic strength (1.6 M NaCl or 0.25 M (NH4)2SO4 as well as DNase I digestion. Using indirect immunofluorescence experiments and monoclonal antibodies we show that heating to 37 degrees C changes the distribution of a 160 kDa protein previously shown to be a component of the inner matrix network. On the other hand, a 125 kDa polypeptide was not affected at all by the incubation. Our results clearly indicate that the inclusion of a 37 degrees C incubation (for example during digestion with DNase I) in the protocol to obtain the in situ nuclear matrix can result in the formation of in vitro artifacts.

Plasma membrane cyclic nucleotide gated calcium channels control land plant thermal sensing and acquired thermotolerance.

Typically at dawn on a hot summer day, land plants need precise molecular thermometers to sense harmless increments in the ambient temperature to induce a timely heat shock response (HSR) and accumulate protective heat shock proteins in anticipation of harmful temperatures at mid-day. Here, we found that the cyclic nucleotide gated calcium channel (CNGC) CNGCb gene from Physcomitrella patens and its Arabidopsis thaliana ortholog CNGC2, encode a component of cyclic nucleotide gated Ca(2+) channels that act as the primary thermosensors of land plant cells. Disruption of CNGCb or CNGC2 produced a hyper-thermosensitive phenotype, giving rise to an HSR and acquired thermotolerance at significantly milder heat-priming treatments than in wild-type plants. In an aequorin-expressing moss, CNGCb loss-of-function caused a hyper-thermoresponsive Ca(2+) influx and altered Ca(2+) signaling. Patch clamp recordings on moss protoplasts showed the presence of three distinct thermoresponsive Ca(2+) channels in wild-type cells. Deletion of CNGCb led to a total absence of one and increased the open probability of the remaining two thermoresponsive Ca(2+) channels. Thus, CNGC2 and CNGCb are expected to form heteromeric Ca(2+) channels with other related CNGCs. These channels in the plasma membrane respond to increments in the ambient temperature by triggering an optimal HSR, leading to the onset of plant acquired thermotolerance.

Membrane fluidization triggers membrane remodeling which affects the thermotolerance in Escherichia coli.

Treatment of Escherichia coli with non-lethal doses of heat or benzyl alcohol (BA) causes transient membrane fluidization and permeabilization, and induces the rapid transcription of heat-shock genes in a sigma32-dependent manner. This early response is followed by a rapid adaptation (priming) of the cells to otherwise lethal elevated temperature, in strong correlation with an observed remodeling of the composition and alkyl chain unsaturation of membrane lipids. The acquisition of cellular thermotolerance in BA-primed cells is unrelated to protein denaturation and is not accompanied by the formation of major heat-shock proteins, such as GroEL and DnaK. This suggests that the rapid remodeling of membrane composition is sufficient for the short-term bacterial thermotolerance.

Relation of heart rate to percent VO2 peak during submaximal exercise in the heat.

We tested the hypothesis that elevation in heart rate (HR) during submaximal exercise in the heat is related, in part, to increased percentage of maximal O(2) uptake (%Vo(2 max)) utilized due to reduced maximal O(2) uptake (Vo(2 max)) measured after exercise under the same thermal conditions. Peak O(2) uptake (Vo(2 peak)), O(2) uptake, and HR during submaximal exercise were measured in 22 male and female runners under four environmental conditions designed to manipulate HR during submaximal exercise and Vo(2 peak). The conditions involved walking for 20 min at approximately 33% of control Vo(2 max) in 25, 35, 40, and 45 degrees C followed immediately by measurement of Vo(2 peak) in the same thermal environment. Vo(2 peak) decreased progressively (3.77 +/- 0.19, 3.61 +/- 0.18, 3.44 +/- 0.17, and 3.13 +/- 0.16 l/min) and HR at the end of the submaximal exercise increased progressively (107 +/- 2, 112 +/- 2, 120 +/- 2, and 137 +/- 2 beats/min) with increasing ambient temperature (T(a)). HR and %Vo(2 peak) increased in an identical fashion with increasing T(a). We conclude that elevation in HR during submaximal exercise in the heat is related, in part, to the increase in %Vo(2 peak) utilized, which is caused by reduced Vo(2 peak) measured during exercise in the heat. At high T(a), the dissociation of HR from %Vo(2 peak) measured after sustained submaximal exercise is less than if Vo(2 max) is assumed to be unchanged during exercise in the heat.