Current and expected changes in global climate are major threat for biological diversity affecting individuals, communities and ecosystems. However, there is no general trend in the plants response to the climate change. The aim of present study was to evaluate impact of the future climate changes on the distribution of holomycotrophic orchid species using ecological niche modeling approach. Three different scenarios of future climate changes were tested to obtain the most comprehensive insight in the possible habitat loss of 16 holomycotrophic orchids. The extinction of Cephalanthera austiniae was predicted in all analyses. The coverage of suitable niches of Pogoniopsis schenckii will decrease to 1-30% of its current extent. The reduction of at least 50% of climatic niche of Erythrorchis cassythoides and Limodorum abortivum will be observed. In turn, the coverage of suitable niches of Hexalectris spicata, Uleiorchis ulaei and Wullschlaegelia calcarata may be even 16-74 times larger than in the present time. The conducted niche modeling and analysis of the similarity of their climatic tolerance showed instead that the future modification of the coverage of their suitable niches will not be unified and the future climate changes may be not so harmful for holomycotrophic orchids as expected.

• MeSH
• biodiverzita * MeSH
• ekosystém * MeSH
• globální oteplování * MeSH
• klimatické změny MeSH
• lidé MeSH
• Orchidaceae genetika   růst a vývoj   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Few invertebrates can survive cryopreservation in liquid nitrogen, and the mechanisms by which some species do survive are underexplored, despite high application potential. Here, we turn to the drosophilid Chymomyza costata to strengthen our fundamental understanding of extreme freeze tolerance and gain insights about potential avenues for cryopreservation of biological materials. We first use RNAseq to generate transcriptomes of three C. costata larval phenotypic variants: those warm-acclimated in early or late diapause (weak capacity to survive cryopreservation), and those undergoing cold acclimation after diapause entry (extremely freeze tolerant, surviving cryopreservation). We identify mRNA transcripts representing genes and processes that accompany the physiological transition to extreme freeze tolerance and relate cryopreservation survival to the transcriptional profiles of select candidate genes using extended sampling of phenotypic variants. Enhanced capacity for protein folding, refolding and processing appears to be a central theme of extreme freeze tolerance and may allow cold-acclimated larvae to repair or eliminate proteins damaged by freezing (thus mitigating the toxicity of denatured proteins, endoplasmic reticulum stress and subsequent apoptosis). We also find a number of candidate genes (including both known and potentially novel, unannotated sequences) whose expression profiles tightly mirror the change in extreme freeze tolerance status among phenotypic variants.

• MeSH
• aklimatizace genetika   MeSH
• Drosophilidae genetika   MeSH
• hmyz genetika   MeSH
• transkriptom MeSH
• zmrazování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Substantial increases in cardiac output (CO), stroke volume (SV), and gastrointestinal blood flow are essential for euryhaline rainbow trout (Oncorhyncus mykiss) osmoregulation in seawater. However, the underlying hemodynamic mechanisms responsible for these changes are unknown. By examining a range of circulatory and cardiac morphological variables of seawater- and freshwater-acclimated rainbow trout, the present study revealed a significantly higher central venous pressure (CVP) in seawater-acclimated trout (~0.09 vs. -0.02 kPa). This serves to increase cardiac end-diastolic volume in seawater and explains the elevations in SV (~0.41 vs. 0.27 ml/kg) and CO (~21.5 vs. 14.2 ml·min(-1)·kg(-1)) when compared with trout in freshwater. Furthermore, these hemodynamic modifications coincided with a significant increase in the proportion of compact myocardium, which may be necessary to compensate for the increased wall tension associated with a larger stroke volume. Following a temperature increase from 10 to 16.5°C, both acclimation groups exhibited similar increases in heart rate (Q10 of ~2), but SV tended to decrease in seawater-acclimated trout despite the fact that CVP was maintained in both groups. This resulted in CO of seawater- and freshwater-acclimated trout stabilizing at a similar level after warming (~26 ml·min(-1)·kg(-1)). The consistently higher CVP of seawater-acclimated trout suggests that factors other than compromised cardiac filling constrained the SV and CO of these individuals at high temperatures. The present study highlights, for the first time, the complex interacting effects of temperature and water salinity on cardiovascular responses in a euryhaline fish species.

• MeSH
• centrální žilní tlak fyziologie   MeSH
• minutový srdeční výdej fyziologie   MeSH
• mořská voda * MeSH
• Oncorhynchus mykiss fyziologie   MeSH
• osmoregulace fyziologie   MeSH
• remodelace komor fyziologie   MeSH
• tepový objem fyziologie   MeSH
• tolerance k soli fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The fruit fly Drosophila melanogaster is an insect of tropical origin. Its larval stage is evolutionarily adapted for rapid growth and development under warm conditions and shows high sensitivity to cold. In this study, we further developed an optimal acclimation and freezing protocol that significantly improves larval freeze tolerance (an ability to survive at -5°C when most of the freezable fraction of water is converted to ice). Using the optimal protocol, freeze survival to adult stage increased from 0.7% to 12.6% in the larvae fed standard diet (agar, sugar, yeast, cornmeal). Next, we fed the larvae diets augmented with 31 different amino compounds, administered in different concentrations, and observed their effects on larval metabolomic composition, viability, rate of development and freeze tolerance. While some diet additives were toxic, others showed positive effects on freeze tolerance. Statistical correlation revealed tight association between high freeze tolerance and high levels of amino compounds involved in arginine and proline metabolism. Proline- and arginine-augmented diets showed the highest potential, improving freeze survival to 42.1% and 50.6%, respectively. Two plausible mechanisms by which high concentrations of proline and arginine might stimulate high freeze tolerance are discussed: (i) proline, probably in combination with trehalose, could reduce partial unfolding of proteins and prevent membrane fusions in the larvae exposed to thermal stress (prior to freezing) or during freeze dehydration; (ii) both arginine and proline are exceptional among amino compounds in their ability to form supramolecular aggregates which probably bind partially unfolded proteins and inhibit their aggregation under increasing freeze dehydration.

• MeSH
• aklimatizace účinky léků   MeSH
• analýza hlavních komponent MeSH
• arginin farmakologie   MeSH
• dieta MeSH
• Drosophila melanogaster účinky léků   fyziologie   MeSH
• fyziologická adaptace účinky léků   MeSH
• larva MeSH
• metabolomika MeSH
• potravinářské přísady farmakologie   MeSH
• prolin farmakologie   MeSH
• zmrazování * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Cold exposure depolarizes cells in insects due to a reduced electrogenic ion transport and a gradual increase in extracellular K+ concentration ([K+]). Cold-induced depolarization is linked to cold injury in chill-susceptible insects, and the locust, Locusta migratoria, has been shown to improve cold tolerance following cold acclimation through depolarization resistance. Here we investigate how cold acclimation influences depolarization resistance and how this resistance relates to improved cold tolerance. To address this question, we investigated if cold acclimation affects the electrogenic transport capacity and/or the relative K+ permeability during cold exposure by measuring membrane potentials of warm- and cold-acclimated locusts in the presence and absence of ouabain (Na+-K+ pump blocker) or 4-aminopyridine (4-AP; voltage-gated K+ channel blocker). In addition, we compared the membrane lipid composition of muscle tissue from warm- and cold-acclimated locust and the abundance of a range transcripts related to ion transport and cell injury accumulation. We found that cold-acclimated locusts are depolarization resistant due to an elevated K+ permeability, facilitated by opening of 4-AP-sensitive K+ channels. In accordance, cold acclimation was associated with an increased abundance of Shaker transcripts (gene encoding 4-AP-sensitive voltage-gated K+ channels). Furthermore, we found that cold acclimation improved muscle cell viability following exposure to cold and hyperkalemia even when muscles were depolarized substantially. Thus cold acclimation confers resistance to depolarization by altering the relative ion permeability, but cold-acclimated locusts are also more tolerant to depolarization.

• MeSH
• 4-aminopyridin farmakologie   MeSH
• aklimatizace účinky léků   fyziologie   MeSH
• kosterní svalová vlákna účinky léků   fyziologie   MeSH
• Locusta migratoria fyziologie   MeSH
• membránové potenciály účinky léků   fyziologie   MeSH
• nízká teplota * MeSH
• ouabain farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Adults of the bug Pyrrhocoris apterus and the beetle Alphitobius diaperinus developed chill-injury slower and survived longer when they were exposed to fluctuating thermal regimes (FTRs, where periods of low temperature were alternated with periods of higher temperature on a daily basis) rather than to constant low temperatures. The extracellular (haemolymph) concentrations of potassium ions increased with significantly higher rates in the insects exposed to constant low temperatures than in those exposed to FTRs. The concentrations of magnesium and sodium ions were maintained relatively constant or decreased slightly in both thermal regimes. The loss of body water and the increase of haemolymph osmolality contributed to, but could not fully explain, the ion concentration changes, which probably resulted also from impairing the function of an active metabolic component (ion pump) at low temperatures. This explanation was supported by observing (in P. apterus) the return toward normal [K+] during the warm "recovery" period of the FTR. Collectively, the paper stresses the importance of considering the temperature fluctuations in the experimental studies on insect cold tolerance and suggests that the positive effect of the FTR on cold tolerance may consist, at least partially, in allowing the primary ion pumping systems to re-establish the ion gradients across cell membranes and epithelia during the recovery periods at a higher temperature.

• MeSH
• draslík metabolismus   MeSH
• financování organizované MeSH
• fyziologická adaptace MeSH
• hemolymfa metabolismus   MeSH
• hmyz fyziologie   MeSH
• hojení ran fyziologie   MeSH
• homeostáza fyziologie   MeSH
• nízká teplota MeSH
• osmolární koncentrace MeSH
• tělesná hmotnost MeSH
• termoregulace fyziologie   MeSH
• voda metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

When exposed to constant low temperatures (CLTs), insects often suffer from cumulative physiological injuries that can severely compromise their fitness and survival. Yet, mortality can be considerably lowered when the cold stress period is interrupted by periodic warm interruption(s), referred to as fluctuating thermal regimes, FTRs. In this study, we have shown that FTRs strongly promoted cold tolerance of Drosophila melanogaster adults. We then assessed whether this marked phenotypic shift was associated with detectable physiological changes, such as synthesis of cryoprotectants and/or membrane remodeling. To test these hypotheses, we conducted two different time-series Omics analyzes in adult flies submitted to CLTs vs. FTRs: metabolomics (GC/MS) and lipidomics (LC/ESI/MS) targeting membrane phospholipids. We observed increasing levels in several polyhydric alcohols (arabitol, erythritol, sorbitol, mannitol, glycerol), sugars (fructose, mannose) and amino acids (serine, alanine, glutamine) in flies under CLT. Prolonged exposure to low temperature was also associated with a marked deviation of metabolic homeostasis and warm interruptions as short as 2h were sufficient to periodically return the metabolic system to functionality. Lipidomics revealed an increased relative proportion of phosphatidylethanolamines and a shortening of fatty acyl chains in flies exposed to cold, likely to compensate for the ordering effect of low temperature on membranes. We found a remarkable correspondence in the time-course of changes between the metabolic and phospholipids networks, both suggesting a fast homeostatic regeneration during warm intervals under FTRs. In consequence, we suggest that periodic opportunities to restore system-wide homeostasis contribute to promote cold tolerance under FTRs.

• MeSH
• analýza hlavních komponent MeSH
• Drosophila melanogaster metabolismus   MeSH
• fosfolipidy metabolismus   MeSH
• fyziologická adaptace * MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• lineární modely MeSH
• metabolismus lipidů * MeSH
• metabolomika metody   MeSH
• nízká teplota * MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• pravděpodobnost MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Expression of heat shock proteins has been proposed as an underlying mechanism of increased cold tolerance in insects exposed to fluctuating thermal regimes (FTRs) in comparison to constant low temperatures (CLTs). We found that the levels of Pahsp70 mRNA increase by up to 3 orders in the linden bugs, Pyrrhocoris apterus exposed to FTR -5 degree C (22h) and 25 degree C (2h). The 2h-long warm pulses, however, were not sufficient for accumulation of PaHSP70 protein and thus no significant difference in expression of PaHSP70 protein was detected between FTR and CLT regimes. Hence, we conclude that the accumulation of PaHSP70 protein is not the mechanism underlying the increased cold tolerance in P. apterus at the particular FTR used in this study. The relevance of some other possible mechanisms is discussed.

• MeSH
• fyziologická adaptace fyziologie   MeSH
• hmyz fyziologie   MeSH
• messenger RNA metabolismus   MeSH
• nízká teplota MeSH
• proteiny tepelného šoku HSP70 fyziologie   genetika   MeSH
• termoregulace fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Úvod: Cílem článku je ukázat experimentální a klinické výsledky odpovědi ledvin na teplou a studenou ischemii. Porovnává různé operační postupy a možnosti ovlivnění ledvinné ischemie při resekcích ledvin. Článek je souhrnem aktuálních literárních údajů. Výsledky: Existují tři hlavní mechanizmy ischemického poškození ledvin – cévní mechanizmus s přetrvávající vazokonstrikcí a abnormální reakcí endoteliálních buněk, tubulární obstrukce se zpětným tokem moči a reperfuzní poškození. Spor trvá o maximální toleranci teplé ischemie (WI), která může být ovlivněna hlavně chirurgickou technikou. Závěr: Pokud je předpokládáno při operaci využití ischemie, nádor by měl být odstraněn v co nejkratší možné době. Obecně je doporučován čas kratší než 25 minut teplé ischemie bez ohledu na typ chirurgického přístupu. Pokud je možnost provedení resekce v tomto čase ohrožena, je třeba začít včas s chlazením ledviny. Studená ischemie (cold ischemia – CI) může být dle závislosti na způsobu chlazení tolerována až do doby dvou hodin (autotransplantace). K možným druhům chlazení při resekčních výkonech patří metoda in situ studené arteriální perfuze, povrchové chlazení ledovou tříští, retrográdní perfuze dutého systému nebo ex situ studená arteriální perfuze s autotransplantací. Technika metod dosažení CI závisí na předoperačním hodnocení nálezu, chirurgické technice (otevřená, laparoskopická nebo robotická operace) a zvyklostech pracoviště.

Introduction: The objective of this literature review was to summarize clinical and experimental evidence of the renal responses to warm and cold ischemia. The study compared different surgical procedures and options for dealing with renal ischemia during partial nephrectomy. The article is a summary of the current literature data. Results: There are three main mechanisms of ischemic renal injury – vascular, persistent vasoconstriction with an abnormal endothelial cell compensatory response, and tubular obstruction, with backflow of urine, and injury due to reperfusion. Controversy regarding the maximal kidney tolerability to warm ischemia continues. This communication summarizes literary data regarding available surgical techniques used to diminish the effects of warm ischemia. Conclusion: If ischemia is required, the tumour should be removed within 25 minutes of warm ischemia, regardless of the surgical approach. If this longer time of resection is expected, we have to start immediately with cold ischemia. Cold ischemia, depending on the cooling method, can be tolerated for up to 2 hours (autotransplantation). The cold ischemia technique includes in situ cold arterial perfusion, ice slush placed around the kidney, retrograde caliceal perfusion or ex situ cold arterial perfusion with autotransplantation. The technique depends on preoperative findings, surgical technique (open, laparoscopic or robotic) and institutional experience.

• MeSH
• časové faktory MeSH
• ischemie patofyziologie   MeSH
• laparoskopie MeSH
• ledviny chirurgie   krevní zásobení   patofyziologie   MeSH
• lidé MeSH
• mannitol aplikace a dávkování   MeSH
• nádory ledvin * chirurgie   MeSH
• nefrektomie MeSH
• obnova funkce MeSH
• peroperační péče MeSH
• pooperační komplikace MeSH
• radioisotopová scintigrafie MeSH
• renální insuficience etiologie   MeSH
• studená ischemie * MeSH
• teplá ischemie * MeSH
• urologické chirurgické výkony MeSH
• vyšetření funkce ledvin metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH

Autoimunitní hemolytická anemie (AIHA) vzniká v důsledku tvorby autoprotilátek namířených proti některému z membránových antigenů erytrocytu, což vede k intravaskulární hemolýze aktivací komplementu, či k zániku erytrocytů s navázanou protilátkou v monocyto-makrofágovém systému sleziny. Základní klasifikace rozděluje autoimunitní hemolytické anémie na primární (idiopatickou) a sekundární, způsobenou přítomností známé vyvolávající příčiny. Podle charakteru přítomných protilátek dělíme onemocnění na AIHA s tepelnými protilátkami, AIHA s chladovými protilátkami, AIHA se smíšeným typem protilátek a paroxyzmální chladovou hemoglobinurii. V patogenezi AIHA se uplatňuje porucha prezentace antigenů imunokompetentním buňkám, porucha indukce tolerance T-lymfocytů vůči autoantigenům a indukce tvorby protilátek B-lymfocyty Základním diagnostickým testem u AIHA je přímý a nepřímý Coombsův antiglobulinový test. V léčbě AIHA s tepelnými protilátkami se v I. linii stále uplatňuje podávání kortikosteroidů. U nemocných neodpovídajících na I. linii léčby je v současnosti ve II. linii léčby doporučována splenektomie či podávání rituximabu, kombinovaná imunosuprese se uplatňuje jako další léčba linie při relapsech či malém efektu I. a II. linie léčby. U choroby z chladových aglutininů je lékem volby rituximab.

Autoimmune hemolytic anemia (AIHA) is caused by auto-antibodies directed against self red blood cell (RBC) surface antigens. A consequence may be an intravascular hemolysis mediated by activated complement or extravascular hemolysis caused by destruction of complex of RBC with autoantibody in spleen and liver. The basic classification subdivides AIHA in primary/idiopathic and secondary with known underlying disease. A classification according to the thermal range of antibody recognizes warm AIHA, cold aglutinin disease (CAD), mixed AIHA and paroxysmal cold hemoglobinuria. Pathogenesis of AIHA consists of a defective antigen presentation to immunocompetent cells, insufficient process of T-lymphocyte tolerance to autoantigens and induction of autoantibody production by B-lymphocytes. For the diagnosis of AIHA are essential direct and indirect antiglobulin tests. The first-line therapy for warm AIHA is still administration of corticosteroids. For non-responding patients, second-line treatment includes rituximab or splenectomy. Combination of other immunosuppressive drugs represents a third-line treatment for resistant/relapsing patients. Rituximab is a treatment of choice for patients with CAD.

• MeSH
• autoimunitní hemolytická anemie * diagnóza   klasifikace   patofyziologie   terapie   MeSH
• diferenciální diagnóza MeSH
• glukokortikoidy aplikace a dávkování   terapeutické užití   MeSH
• hemolýza MeSH
• imunologické faktory MeSH
• imunosupresiva terapeutické užití   MeSH
• lidé MeSH
• rituximab aplikace a dávkování   terapeutické užití   MeSH
• splenektomie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH