Half Of Animals Research Articles

Physical exercise prevents and mitigates non-alcoholic steatohepatitis-induced liver mitochondrial structural and bioenergetics impairments

Exercise is considered a non-pharmacological tool against several lifestyle disorders in which mitochondrial dysfunction is involved. The present study aimed to analyze the preventive (voluntary physical activity—VPA) and therapeutic (endurance training—ET) role of exercise against non-alcoholic steatohepatitis (NASH)-induced liver mitochondrial dysfunction. Sixty male Sprague–Dawley rats were divided into standard-diet sedentary (SS, n=20), standard-diet VPA (SVPA, n=10), high-fat diet sedentary (HS, n=20) and high-fat diet VPA (HVPA, n=10). After 9weeks of diet-treatment, half of SS and HS animals were engaged in an ET program (SET and HET) for 8weeks, 5days/week and 60min/day. Liver mitochondrial oxygen consumption and transmembrane-electric potential (ΔΨ) were evaluated in the presence of glutamate–malate (G/M), palmitoyl–malate (P/M) and succinate (S/R). Mitochondrial enzymes activity, lipid and protein oxidation, oxidative phosphorylation (OXPHOS) subunits, cytochrome c, adenine nucleotide translocator (ANT) and uncoupling protein-2 (UCP2) content were assessed. HS groups show the histological features of NASH in parallel with decreased ΔΨ and respiratory control (RCR) and ADP/O ratios (G/M and P/M). A state 3 decrease (G/M and S/R), FCCP-induced uncoupling respiration (S/R) and ANT content were also observed. Both exercise types counteracted oxygen consumption (RCR, ADP/O and FCCP-uncoupling state) impairments and improved ΔΨ (lag-phase). In conclusion, exercise prevented or reverted (VPA and ET, respectively) the bioenergetic impairment induced by NASH, but only ET positively remodeled NASH-induced liver structural damage and abnormal mitochondria. It is possible that alterations in inner membrane integrity and fatty acid oxidation may be related to the observed phenotypes induced by exercise.

The influence of vitamin B12 supplementation on the level of white blood cells and lymphocytes phenotype in rats fed a low-protein diet.

Protein malnutrition has a negative effect on body composition and some blood parameters, especially in the young growing organism. One of nutritional factors which could protect against negative consequences of protein deficiency may be B group vitamins. The aim of the study was to investigate the effect of vitamin B12 supplementation on the immune system in rats fed a standard and a low-protein diet. Rats were fed a control (20% of energy from protein) or a protein-deficient diet (4.5% of energy from protein). Half of animals in each group were additionally supplemented with vitamin B12 (300% of the daily intake). The white blood cells analysis and lymphocytes immunophenotyping (number and percentage) were performed. Low-protein diets caused disturbances in WBC and lymphocyte subpopulations in both short- (30-day) as well as long-term periods (90-day). Vitamin B12 supplementation significantly reduced the negative impact of protein malnutrition after 30 days, however had no effect on long-term malnutrition. Furthermore, vitamin B12 addition in rats fed a control diet did not affect the studied parameters. This observation opens the promise of use of vitamin B12 supplementation to improve immune system parameters in protein malnourished organisms.

Peritraumatic startle response predicts the vulnerability to develop PTSD-like behaviors in rats: a model for peritraumatic dissociation

Peritraumatic dissociation, a state characterized by alteration in perception and reduced awareness of surroundings, is considered to be a risk factor for the development of post-traumatic stress disorder (PTSD). However, the predictive ability of peritraumatic dissociation is questioned for the inconsistent results in different time points of assessment. The startle reflex is an objective behavioral measurement of defensive response to abrupt and intense sensory stimulus of surroundings, with potential to be used as an assessment on the dissociative status in both humans and rodents. The present study examined the predictive effect of acoustic startle response (ASR) in different time points around the traumatic event in an animal model of PTSD. The PTSD-like symptoms, including hyperarousal, avoidance, and contextual fear, were assessed 2–3 weeks post-trauma. The results showed that (1) the startle amplitude attenuated immediate after intense footshock in almost half of the stress animals, and (2) the attenuated startle responses at 1 h but not 24 h after stress predicted the development of severe PTSD-like symptoms. These data indicate that the startle alteration at the immediate period after trauma, including 1 h, is more important in PTSD prediction than 24 h after trauma. Our study also suggests that the startle attenuation immediate after intense stress may serve as an objective measurement of peritraumatic dissociation in rats.

Citations

Citations

Age-related impairments on one hippocampal-dependent task predict impairments on a subsequent hippocampal-dependent task.

Age-related cognitive impairments are particularly prevalent in forms of learning that require a functionally intact hippocampal formation, such as spatial and declarative learning. However, there is notable heterogeneity in the cognitive abilities of aged subjects. To date, few studies have determined whether age-related impairments on one learning task relate to impairments on different learning tasks that engage overlapping cognitive processes. Here, we hypothesized that aged animals that were impaired on 1 hippocampal-dependent behavioral procedure would be impaired on a second hippocampal-dependent procedure. Conversely, aged animals that were unimpaired on 1 hippocampal-dependent task would be unimpaired with a subsequent hippocampal-dependent form of learning. To test these hypotheses, we trained young (2-3 months old) and aged (28-29 months old) F344XBN male rats with trace eyeblink conditioning, followed by the Morris water maze. Half of aged rats were impaired during trace conditioning. Nearly half of aged animals were also impaired during water maze probe testing. Performance during trace conditioning correlated with performance during water maze testing in aged animals. Further analyses revealed that, as a group, aged animals that were impaired on 1 hippocampal-dependent task were impaired on both tasks. Conversely, aged animals that were unimpaired on 1 task were unimpaired on both tasks. Together, these results suggest that aged-related impairments on 1 hippocampal-dependent task predict age-related impairments on a second hippocampal-dependent procedure. These results have implications for assigning personalized therapeutics to ameliorate age-related cognitive decline.

Development of a suturing device for anastomosis for small caliber arteries

The use of minimally invasive and robotic operations has been increasing for coronary artery bypass surgery; however, no suturing devices have been universally adopted for use in these procedures. We developed a new suturing device that enables omission of manual ligation after a running suture. Twenty-two rabbits were used in this study. In 22 rabbits, the right carotid artery was bypassed using an autologous jugular vein graft. Half of the animals were operated on using the new device and the other half using conventional suturing methods. Postoperative evaluations were performed at 1, 3, and 6 months. Suturing time was 15.6 ± 2.4 min in the device group and 16.6 ± 4.4 min in the control group (p = 0.34). Graft patency and blood flow measurements were not significantly different between the two groups. Histopathological examination of the anastomotic site showed common inflammatory responses in both groups. No particular histopathological change was seen related to the device. In conclusion, the safety of the new suturing device was confirmed, and its efficacy was equal to that of the conventional suturing technique.

Effects of the interaction between zolpidem and sleep deprivation on memory in mice

Zolpidem (Zolp), a hypnotic drug prescribed to treat insomnia, may have negative effects on memory. Considering the clinical context, Zolp is usually prescribed as a repeated treatment for insomnia. However, as far as we know no studies have characterized the cognitive effects of Zolp neither as repeated administration nor in animal models of insomnia. Thus, the aim of this study was to evaluate the effects of the repeated administration of Zolp (or its abstinence) on learning and memory of mice submitted to total sleep deprivation (TSD) and evaluated in the plus-maze discriminative avoidance task (PM-DAT). Three-month-old Swiss male mice were subjected to control condition (CTRL) or to TSD by gentle handling for 3 h per day during 10 days. Every day, after the TSD period, mice were treated with saline (Sal) or 5 mg/kg Zolp. On the 10th day, half of animals treated with Sal received an acute Zolp injection while the others received Sal. Still, half of the animals treated with Zolp received one more Zolp injection while the others receive Sal. Thirty min after the last injection, mice were trained in the PM-DAT and tested 12 days later. In the training, there were no differences among groups on learning. Regarding locomotion, all animals that received Zolp before training – irrespective of sleep condition or previous treatment – had motor activity decreased when compared to their respective controls. Still, mice subjected to TSD, which had acutely received Zolp, explored more the apparatus when compared to their CTRL group. In the testing, both the acute and repeated administrations of Zolp promoted amnesia on CTRL groups. The abstinence had no effects either on CTRL or on TSD groups. Concerning TSD, it induced memory deficits per se, which were counteracted by the acute administration of Zolp, but not by the repeated one. Our data revealed that acute treatment with Zolp abolished TSD-induced memory impairment. Additionally, the repeated treatment of Zolp did not promote tolerance to the amnestic effect induced by its acute administration. Our findings demonstrate the importance of a systematic evaluation of the interactions between sleep restriction periods and Zolp on memory. FAPESP, AFIP, CNPq, CAPES.

Behavioral impairments in rats with chronic epilepsy suggest comorbidity between epilepsy and attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is encountered among patients with epilepsy at a significantly higher rate than in the general population. Mechanisms of epilepsy–ADHD comorbidity remain largely unknown. We investigated whether a model of chronic epilepsy in rats produces signs of ADHD, and thus, whether it can be used for studying mechanisms of this comorbidity. Epilepsy was induced in male Wistar rats via pilocarpine status epilepticus. Half of the animals exhibited chronic ADHD-like abnormalities, particularly increased impulsivity and diminished attention in the lateralized reaction-time task. These impairments correlated with the suppressed noradrenergic transmission in locus coeruleus outputs. The other half of animals exhibited depressive behavior in the forced swimming test congruently with the diminished serotonergic transmission in raphe nucleus outputs. Attention deficit/hyperactivity disorder and depressive behavior appeared mutually exclusive. Therefore, the pilocarpine model of epilepsy affords a system for reproducing and studying mechanisms of comorbidity between epilepsy and both ADHD and/or depression.

Embryonic left–right separation mechanism allows confinement of mutation‐induced phenotypes to one lateral body half of bilaterians

A fundamental question in developmental biology is how a chimeric animal such as a bilateral gynandromorphic animal can have different phenotypes confined to different lateral body halves, and how mutation-induced phenotypes, such as genetic diseases, can be confined to one lateral body half in patients. Here, I propose that embryos of many, if not all, bilaterian animals are divided into left and right halves at a very early stage (which may vary among different types of animals), after which the descendants of the left-sided and right-sided cells will almost exclusively remain on their original sides, respectively, throughout the remaining development. This embryonic left-right separation mechanism allows (1) mutations and the mutation-induced phenotypes to be strictly confined to one lateral body half in animals and humans; (2) mothers with bilateral hereditary primary breast cancer to transmit their disease to their offspring at twofold of the rate compared to mothers with unilateral hereditary breast cancer; and (3) a mosaic embryo carrying genetic or epigenetic mutations to develop into either an individual with the mutation-induced phenotype confined unilaterally, or a pair of twins displaying complete, partial, or mirror-image discordance for the phenotype. Further, this left-right separation mechanism predicts that the two lateral halves of a patient carrying a unilateral genetic disease can each serve as a case and an internal control, respectively, for genetic and epigenetic comparative studies to identify the disease causations.

Cardiorespiratory effects of gap junction blockade in the locus coeruleus in unanesthetized adult rats

The locus coeruleus (LC) plays an important role in central chemoreception. In young rats (P9 or younger), 85% of LC neurons increase firing rate in response to hypercapnia vs. only about 45% of neurons from rats P10 or older. Carbenoxolone (CARB – gap junction blocker) does not affect the % of LC neurons responding in young rats but it decreases the % responding by half in older animals. We evaluated the participation of gap junctions in the CO2 ventilatory response in unanesthetized adult rats by bilaterally microinjecting CARB (300μM, 1mM or 3mM/100nL), glycyrrhizic acid (GZA, CARB analog, 3mM) or vehicle (aCSF – artificial cerebrospinal fluid) into the LC of Wistar rats. Bilateral gap junction blockade in LC neurons did not affect resting ventilation; however, the increase in ventilation produced by hypercapnia (7% CO2) was reduced by ∼25% after CARB 1mM or 3mM injection (1939.7±104.8mLkg−1min−1 for the aCSF group and 1468.3±122.2mLkg−1min−1 for 1mM CARB, P<0.05; 1939.7±104.8mLkg−1min−1 for the aCSF group and 1540.9±68.4mLkg−1min−1 for the 3mM CARB group, P<0.05) due largely to a decrease in respiratory frequency. GZA injection or CARB injection outside the LC (peri-LC) had no effect on ventilation under any conditions. The results suggest that gap junctions in the LC modulate the hypercapnic ventilatory response of adult rats.

The Play of Ethics in Eugen Fink

The Play of Ethics in Eugen Fink

14-Deoxyandrographolide targets adenylate cyclase and prevents ethanol-induced liver injury through constitutive NOS dependent reduced redox signaling in rats

Chronic alcoholism is one of the most common causes of liver diseases worldwide. Nitric oxide (NO) has been proposed to have potential for clinical application against chronic hepatocellular injuries. However, mechanisms underlying hepatoprotective functions of NO in ethanol-induced apoptosis are largely unknown. Sprauge-Dawley rats were exposed to ethanol for 8 weeks. Half of the ethanol-fed animals received 14-deoxyandrographolide (14-DAG) treatment for the last 4 weeks of study. Preventive effect of 14-DAG against ethanol-induced hepatotoxicity involved constitutive nitric oxide synthase (cNOS) activation followed by up-regulation of γ-glutamylcysteine synthetase activity and reduced oxidative stress. Enhanced interaction of cNOS with caveolin-1 caused down-regulation of enzyme activity and led to depletion of NO in the hepatocytes of ethanol-fed animals. 14-DAG acted as activator of adenylate cyclase and modulated cyclic AMP (cAMP) mediated expression of caveolin-1 and calmodulin. This eventually favored activation of cNOS through inhibition of cNOS-caveolin-1 interaction. Our results suggest that, protective effect of 14-DAG against ethanol-induced hepatic injury is based on its ability to reduce oxidative stress through cNOS dependent improvement of redox status. 14-DAG mediated activation of adenylate cyclase-cAMP signaling leading to up-regulation of cNOS may provide a promising approach in the prevention of liver diseases during chronic alcoholism.

Calpain‐1 inhibitor prevent loss of dystrophin in experimental septic cardiomyopathy induced by cecal ligation and puncture (CLP)

This study was designed to test the hypothesis that N‐Acetyl‐Lleucyl‐L‐leucyl‐L‐norleucinal (ALLN), calpain‐1 inhibitor, could attenuate dystrophin disruption and cardiac contractile proteins loss/reduction in experimental sepsis induced by CLP. Male C57Bl/6 mice were subjected to sham and severe septic injury (SSI) induced by CLP. Half of animals from each group were treated with ALLN (3mg/kg, SSI+ALLN; SH+ALLN) 4hs after surgery. In SSI+ALLN mice reduced amounts of myocardial calpain‐1 were associated with increased actin/myosin expression as compared to SSI mice. Additionally, ALLN treatment of septic mice significantly prevented loss of dystrophin and â‐dystroglycan as compared to SSI mice. Concurrently, SSI+ALLN mice presented an increased survival rate.Calpain inhibitor, ALLN, suppressed the increased calpain‐1 expression and prevented myocardial structural injury caused by experimental severe sepsis. These observations reinforce the concept that calpain‐1 activation represents a key target in dystrophin disruption behind cardiac dysfunction in severe sepsis/septic shock. Further studies are needed to elucidate this mechanism that may provide new interventional pathways to prevent septic cardiomyopathy.

A Comparative Genotoxicity Study of a Supraphysiological Dose of Triiodothyronine (T3) in Obese Rats Subjected to Either Calorie-Restricted Diet or Hyperthyroidism

This study was designed to determine the genotoxicity of a supraphysiological dose of triiodothyronine (T3) in both obese and calorie-restricted obese animals. Fifty male Wistar rats were randomly assigned to one of the two following groups: control (C; n = 10) and obese (OB; n = 40). The C group received standard food, whereas the OB group was fed a hypercaloric diet for 20 weeks. After this period, half of the OB animals (n = 20) were subjected to a 25%-calorie restriction of standard diet for 8 weeks forming thus a new group (OR), whereas the remaining OB animals were kept on the initial hypercaloric diet. During the following two weeks, 10 OR animals continued on the calorie restriction diet, whereas the remaining 10 rats of this group formed a new group (ORS) given a supraphysiological dose of T3 (25 µg/100 g body weight) along with the calorie restriction diet. Similarly, the remaining OB animals were divided into two groups, one that continued on the hypercaloric diet (OB, n = 10), and one that received the supraphysiological dose of T3 (25 µg/100 g body weight) along with the hypercaloric diet (OS, n = 10) for two weeks. The OB group showed weight gain, increased adiposity, insulin resistance, increased leptin levels and genotoxicity; T3 administration in OS animals led to an increase in genotoxicity and oxidative stress when compared with the OB group. The OR group showed weight loss and normalized levels of adiposity, insulin resistance, serum leptin and genotoxicity, thus having features similar to those of the C group. On the other hand, the ORS group, compared to OR animals, showed higher genotoxicity. Our results indicate that regardless of diet, a supraphysiological dose of T3 causes genotoxicity and potentiates oxidative stress.

Oral glutamine supplementation improves intestinal permeability dysfunction in a murine acute graft-vs.-host disease model

Although a profound barrier dysfunction has been reported, little is known about the pathophysiological mechanism evoking gastrointestinal graft-vs.-host disease (GI-GvHD) and apparent therapeutic options. The aim of this study was to evaluate the influence of oral glutamine on the course of GI-GvHD in an acute semiallogenic graft-vs.-host disease (GvHD) in irradiated B6D2F1 mice. An acute semiallogenic GvHD was induced by intraperitoneal injection of lymphocytes from C57BL/6 mice to irradiated B6D2F1 mice. Half of the GvHD animals received oral glutamine supplementation for 6 days started at the time of lymphocyte transfer. Six days after induction of the semiallogenic GvHD, jejunum specimens were prepared. The expression of the proinflammatory cytokine TNF-α and the tight junction protein occludin was investigated by PCR. Histological changes along with the apoptotic response were evaluated and intestinal permeability was assessed. Animals with GvHD showed a strong increase in paracellular permeability as a sign of the disturbed barrier function. TNF-α expression was significantly increased and the expression of the tight junction protein occludin decreased. GvHD led to mucosal atrophy, crypt hyperplasia, crypt apoptosis, and a disintegration of the tight junctions. Glutamine-treated mice showed reduced expression of TNF-α, increased occludin expression, fewer histological changes in the jejunum, smaller number of apoptotic cells in the crypt, and reduced gastrointestinal permeability. In conclusion, oral glutamine seems to have beneficial effects on the severity of inflammatory changes in the course of GvHD and might be a therapeutic option.

Significance of Theileria orientalis types in individual affected beef herds in New South Wales based on clinical, smear and PCR findings

Cattle within seven NSW herds with a history or risk of clinical Theileria orientalis disease associated with introductions of cattle were examined clinically and by haematological and PCR testing at sequential bleeds or at single sampling of different risk subgroups. The T. orientalis Ikeda type was detected in all herds and Chitose type was detected in six. Pale and jaundiced mucosal surfaces were associated with clinically affected groups of cattle, and herds containing cattle with ≥1% theilerias in erythrocytes were associated with high prevalence of Ikeda type, with or without Chitose type. In clinically normal cattle within these Ikeda-affected herds, over half of the smear negative animals were detected as infected with Ikeda type, while 90% of smear positive cases were positive for Ikeda type. Infection with Ikeda and Chitose organisms was detected in calves as young as 1–2 weeks, rapidly increased in prevalence within one month and was maintained until 4.5 months of age. In these calves Ikeda prevalence increased at a faster rate than the other MPSP types, particularly Buffeli which is generally considered to be avirulent, and suggests either an increased growth rate or rate of transmission of the Ikeda type or failure of the host immune system to clear this type. Particularly high T. orientalis prevalence rates were detected (in blood samples from a single time point) in adults that had been in direct contact with weaner cattle introduced from coastal areas; however, the lack of direct contact with affected cattle did not prevent infection with Ikeda type in some cases. Spread within previously naïve herds was variable, and results also depended on the sampling time point. In contrast, groups in which infection was already established gave repeatedly similar results at multiple samplings taken at one month intervals. Our results confirm that a large reservoir of infected but clinically normal animals exists within T. orientalis-affected cattle herds and PCR testing of EDTA bloods is more sensitive for detecting subclinical infection than blood smear examination. Direct contact with weaner cattle introduced from coastal areas appears to be a major risk factor for T. orientalis infection in adult cattle. Frequent sampling may be used to monitor spread of T. orientalis within newly affected herds, but may be unrewarding once a high prevalence is established.

Interactions between hypoxia tolerance and food deprivation in Amazonian oscars, Astronotus ocellatus (Agassiz)

Oscars are often subjected to a combination of low levels of oxygen and fasting during nest-guarding on Amazonian floodplains. We questioned whether this anorexia would aggravate the osmo-respiratory compromise. We compared fed and fasted oscars (10-14 days) in both normoxia and hypoxia (10-20 Torr, 4 h). Routine oxygen consumption rates (O2) were increased by 75% in fasted fish, reflecting behavioural differences, whereas fasting improved hypoxia resistance and critical oxygen tensions (Pcrit) lowered from 54 Torr in fed fish to 34 Torr when fasting. In fed fish, hypoxia reduced liver lipid stores by approximately 50% and total liver energy content by 30%. Fasted fish had a 50% lower hepatosomatic index, resulting in lower total liver protein, glycogen and lipid energy stores under normoxia. Compared with hypoxic fed fish, hypoxic fasted fish only showed reduced liver protein levels and even gained glycogen (+50%) on a per gram basis. This confirms the hypothesis that hypoxia-tolerant fish protect their glycogen stores as much as possible as a safeguard for more prolonged hypoxic events. In general, fasted fish showed lower hydroxyacylCoA dehydrogenase activities compared with fed fish, although this effect was only significant in hypoxic fasted fish. Energy stores and activities of enzymes related to energy metabolism in muscle or gills were not affected. Branchial Na(+) uptake rates were more than two times lower in fed fish, whereas Na(+) efflux was similar. Fed and fasted fish quickly reduced Na(+) uptake and efflux during hypoxia, with fasting fish responding more rapidly. Ammonia excretion and K(+) efflux were reduced under hypoxia, indicating decreased transcellular permeability. Fasted fish had more mitochondria-rich cells (MRC), with larger crypts, indicating the increased importance of the branchial uptake route when feeding is limited. Gill MRC density and surface area were greatly reduced under hypoxia, possibly to reduce ion uptake and efflux rates. Density of mucous cells of normoxic fasted fish was approximately fourfold of that in fed fish. Overall, a 10-14 day fasting period had no negative effects on hypoxia tolerance in oscars, as fasted fish were able to respond more quickly to lower oxygen levels, and reduced branchial permeability effectively.

Testing the resource-reallocation hypothesis: influence of maternal testosterone on immune system of Japanese quail (Coturnix japonica) chicks

Event Abstract Back to Event Testing the resource-reallocation hypothesis: influence of maternal testosterone on immune system of Japanese quail (Coturnix japonica) chicks Zuzana Kankova1*, Monika Okuliarova1 and Michal Zeman1, 2 1 Faculty of Natural Sciences, Comenius University, Department of Animal Physiology and Ethology, Slovakia 2 Slovak Academy of Sciences, Institute of Animal Biochemistry and Genetics, Slovakia Immunomodulatory effects of testosterone are frequently discussed but the effects of maternal testosterone (mT) are less studied. Deposition of mT into the egg yolk is generally considered as epigenetic mechanism, enabling transfer of information from the mother to her offspring and better coping with environmental challenges after hatching. In our study we challenge the hypothesis about reallocation of resources between mT-enhanced growth and immune system in Japanese quail selected for high (HET) and low (LET) egg testosterone content since HET quail exhibit faster growth than LET quail. From day 4 after hatching, half of animals (n= 40) was subjected to protein restriction (control group 21%, restricted group 15% of protein content). Subsequently, cell-mediated immune response to phytohemmaglutinine (PHA) and acute phase response to lipopolysaccharide were examined. Acute phase response was evaluated as plasma corticosterone concentrations (Cort), heterophil/lymphocyte (He/Ly) ratio and total immunoglobulin (IgY) levels. Protein restriction negatively influenced body weight and performance in PHA-test. The increase of basal and stimulated Cort and He/Ly ratio and no changes in total IgY levels were observed. HET quail showed higher body mass and total IgY levels and lower He/Ly ratio than LET quail, while PHA index and Cort concentration did not differ between lines. No significant interaction was found between food restriction and genetic line. Therefore, it is unlikely that reallocation of resources induced by mT acts as the main mechanism affecting the immune system of offspring and a compromised immune response probably does not limit selection for high maternal androgen deposition. Keywords: maternal testosterone, protein restriction, cell-mediated immunity, acute phase response, Coturnix japonica Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Innate immunity Citation: Kankova Z, Okuliarova M and Zeman M (2013). Testing the resource-reallocation hypothesis: influence of maternal testosterone on immune system of Japanese quail (Coturnix japonica) chicks. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00194 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Zuzana Kankova, Faculty of Natural Sciences, Comenius University, Department of Animal Physiology and Ethology, Bratislava, Slovakia, z.kankova@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Zuzana Kankova Monika Okuliarova Michal Zeman Google Zuzana Kankova Monika Okuliarova Michal Zeman Google Scholar Zuzana Kankova Monika Okuliarova Michal Zeman PubMed Zuzana Kankova Monika Okuliarova Michal Zeman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Nuclearization of β-catenin in ectodermal precursors confers organizer-like ability to induce endomesoderm and pattern a pluteus larva.

BackgroundIn many bilaterians, asymmetric activation of canonical Wnt (cWnt) signaling at the posterior pole is critical for anterior-posterior (AP) body axis formation. In 16-cell stage sea urchins, nuclearization of β-catenin in micromeres activates a gene regulatory network that defines body axes and induces endomesoderm. Transplanting micromeres to the animal pole of a host embryo induces ectopic endomesoderm in the mesomeres (ectoderm precursors) whereas inhibiting cWnt signaling blocks their endomesoderm-inducing activity and the micromeres become ectoderm-like. We have tested whether ectopic activation of cWnt signaling in mesomeres is sufficient to impart the cells with organizer-like abilities, allowing them to pattern normal embryonic body axes when recombined with a field of mesomeres.ResultsFertilized eggs were microinjected with constitutively active Xenopus β-catenin (actβ-cat) mRNA and allowed to develop until the 16-cell stage. Two mesomeres from injected embryos were then recombined with isolated animal halves (AH) from uninjected 16-cell stage embryos. Control chimeras produced animalized phenotypes (hollow balls of ectoderm) and rarely formed skeletogenic mesoderm (SM)-derived spicules, endoderm or pigment cells, a type of non-skeletogenic mesoderm (NSM). In contrast, over half of the 0.5 pg/pL actβ-cat mesomere/AH chimeras formed a partial or complete gut (exhibiting AP polarity), contained mesenchyme-like cells similar to SM, and produced pigment cells. At three days, chimeras formed plutei with normal embryonic body axes. When fates of the actβ-cat mRNA-injected mesomeres were tracked, we found that injected mesomeres formed mesenchyme-like and pigment cells, but endoderm was induced. Higher concentrations of actβ-cat mRNA were less likely to induce endoderm or pigment cells, but had similar mesenchyme-like cell production to 0.5 pg/pL actβ-cat mesomere/AH chimeras.ConclusionsOur results show that nuclear β-catenin is sufficient to endow naïve cells with the ability to act as an organizing center and that β-catenin has both cell-autonomous and non-autonomous effects on cell fate specification in a concentration-dependent manner. These results are consistent with the hypothesis that a shift in the site of early cWnt signaling in cleaving embryos could have modified polarity of the main body axes during metazoan evolution.

Immunohistochemical identification of Toxoplasma gondii in tissues from Modified Agglutination Test positive sheep

Toxoplasma gondii is a zoonotic agent of great importance in veterinary and public health. The aim of this study was to identify T. gondii by IHC (immunohistochemistry) in different sheep tissues and to determine if an association exists between the results obtained by this method and those obtained by the Modified Agglutination Test (MAT). Tissue specimens of twenty-six sheep seroreactive for T. gondii were selected for histopathological evaluation. The presence of T. gondii was investigated in brain, liver and heart samples by IHC and a possible anti-T. gondii antibody cross reactions with other parasites. McNemar's, Chi-square and Fisher's Exact Tests were applied for the statistical analysis of the results. The analysed tissues showed at least one of the following histopathological changes: mild-to-moderate congestion, focal polymorphonuclear inflammatory infiltrate and multifocal or focal mononuclear inflammatory infiltrate. Sarcocystis spp. were identified in the histological sections from both the heart and diaphragm tissues of 88.5% (23/26) of the animals. A total of 46.2% (12/26) of the T. gondii seroreactive sheep was also positive for T. gondii by IHC in at least one organ (brain, liver or heart). The liver IHC-positivity for T. gondii was statistically equivalent to the global individual IHC-positivity, according to McNemar's test. In addition, IHC allowed the detection of T. gondii in infected animals regardless of the titration observed in the MAT. The statistical difference observed between the three organs when comparing the low titration group, suggested that the heart might be the most suitable organ to detect T. gondii infection by IHC. The IHC results in this study revealed that almost half of MAT positive animals could serve as potential sources of infection for humans because bradyzoites were identified in different tissues, regardless of the MAT titration.