Adolescent neuroimmune function and its interaction with alcohol.

Adolescence is an evolutionarily conserved developmental period associated with behavioral change, including increased risk-taking and alcohol use. Experimentation with alcohol typically begins in adolescence and transitions to binge-like patterns of consumption. Alcohol exposure during adolescence can alter normative changes in brain structure and function. Understanding mechanisms by which ethanol impacts neurodevelopmental processes is important for preventing and ameliorating the deleterious consequences of adolescent alcohol abuse. This review focuses on the neuroimmune system as a key contributor to ethanol-induced changes in adolescent brain and behavior. After brief review of neuroimmune system development, acute and chronic effects of ethanol on adolescent neuroimmune functioning are addressed. Comparisons between stress/immunological challenges and ethanol on adolescent neuroimmunity are reviewed, as cross-sensitization is relevant during adolescence. The mechanisms by which ethanol alters neuroimmune functioning are then discussed, as they may portend development of neuropathological consequences and thus increase vulnerability to subsequent challenges and potentiate addictive behaviors.

Alcohol, inflammation, and blood-brain barrier function in health and disease across development.

Alcohol is the most commonly used drug of abuse in the world and binge drinking is especially harmful to the brain, though the mechanisms by which alcohol compromises overall brain health remain somewhat elusive. A number of brain diseases and pathological states are accompanied by perturbations in Blood-Brain Barrier (BBB) function, ultimately exacerbating disease progression. The BBB is critical for coordinating activity between the peripheral immune system and the brain. Importantly, BBB integrity is responsive to circulating cytokines and other immune-related signaling molecules, which are powerfully modulated by alcohol exposure. This review will highlight key cellular components of the BBB; discuss mechanisms by which permeability is achieved; offer insight into methodological approaches for assessing BBB integrity; and forecast how alcohol-induced changes in the peripheral and central immune systems might influence BBB function in individuals with a history of binge drinking and ultimately Alcohol Use Disorders (AUD).

Adolescent forced swim stress increases social anxiety-like behaviors and alters kappa opioid receptor function in the basolateral amygdala of male rats.

Adolescence is a developmental period marked by robust neural alterations and heightened vulnerability to stress, a factor that is highly associated with increased risk for emotional processing deficits, such as anxiety. Stress-induced upregulation of the dynorphin/kappa opioid receptor (DYN/KOP) system is thought to, in part, underlie the negative affect associated with stress. The basolateral amygdala (BLA) is a key structure involved in anxiety, and neuromodulatory systems, such as the DYN/KOP system, can 1) regulate BLA neural activity in an age-dependent manner in stress-naïve animals and 2) underlie stress-induced anxiety in adults. However, the role of the DYN/KOP system in modulating stress-induced anxiety in adolescents is unknown. To test this, we examined the impact of an acute, 2-day forced swim stress (FSS - 10 min each day) on adolescent (~postnatal day (P) 35) and adult Sprague-Dawley rats (~P70), followed by behavioral, molecular and electrophysiological assessment 24 h following FSS. Adolescent males, but not adult males or females of either age, demonstrated social anxiety-like behavioral alterations indexed via significantly reduced social investigation and preference when tested 24 h following FSS. Conversely, adult males exhibited increased social preference. While there were no FSS-induced changes in expression of genes related to the DYN/KOP system in the BLA, these behavioral alterations were associated with alterations in BLA KOP function. Specifically, while GABA transmission in BLA pyramidal neurons from non-stressed adolescent males responded variably (potentiated, suppressed, or was unchanged) to the KOP agonist, U69593, U69593 significantly inhibited BLA GABA transmission in the majority of neurons from stressed adolescent males, consistent with the observed anxiogenic phenotype in stressed adolescent males. This is the first study to demonstrate stress-induced alterations in BLA KOP function that may contribute to stress-induced social anxiety in adolescent males. Importantly, these findings provide evidence for potential KOP-dependent mechanisms that may contribute to pathophysiological interactions with subsequent stress challenges.

Stress, alcohol and infection during early development: A brief review of common outcomes and mechanisms.

Although stress is an adaptive physiological response to deal with adverse conditions, its occurrence during the early stages of life, such as infancy or adolescence, can induce adaptations in multiple physiological systems, including the reproductive axis, the hypothalamic-pituitary-adrenal (HPA) axis, the limbic cortex and the immune system. These early changes have consequences in adult life, as seen in the physiological and behavioural responses to stress. This review highlights the impact of several stress challenges incurred at various stages of development (perinatal, juvenile, adolescent periods) and how the developmental timing of early-life stress confers unique physiological adaptations that may persist across the lifespan. In doing so, we emphasise how intrinsic sex differences in the stress response might contribute to sex-specific vulnerabilities, the molecular processes underlying stress in the adult, and potential therapeutic interventions to mitigate the effects of early stage stress, including the novel molecular mechanism of SUMOylation as a possible key target of HPA regulation during early-life stress.

Repeated exposure to two stressors in sequence demonstrates that corticosterone and paraventricular nucleus of the hypothalamus interleukin-1ß responses habituate independently.

A wide range of stress-related pathologies such as post-traumatic stress disorder are considered to arise from aberrant or maladaptive forms of stress adaptation. The hypothalamic-pituitary-adrenal (HPA) axis readily adapts to repeated stressor exposure, yet little is known about adaptation in neuroimmune responses to repeated or sequential stress challenges. In Experiment 1, rats were exposed to 10 days of restraint alone (60 minutes daily), forced swim alone (30 minutes daily) or daily sequential exposure to restraint (60 minutes) followed immediately by forced swim (30 minutes), termed sequential stress exposure. Habituation of the corticosterone (CORT) response occurred to restraint by 5 days and swim at 10 days, whereas rats exposed to sequential stress exposure failed to display habituation to the combined challenge. Experiment 2 compared 1 or 5 days of forced swim with sequential stress exposure and examined how each affected expression of several neuroimmune and cellular activation genes in the paraventricular nucleus of the hypothalamus (PVN), prefrontal cortex (PFC) and hippocampus (HPC). Sequential exposure to restraint and swim increased interleukin (IL)-1ß in the PVN, an effect that was attenuated after 5 days. Sequential stress exposure also elicited IL-6 and tumour necrosis factor-α responses in the HPC and PFC, respectively, which did not habituate after 5 days. Experiment 3 tested whether prior habituation to restraint (5 days) would alter the IL-1ß response evoked by swim exposure imposed immediately after the sixth day of restraint. Surprisingly, a history of repeated exposure to restraint attenuated the PVN IL-1ß response after swim in comparison to acutely-exposed subjects despite an equivalent CORT response. Overall, these findings suggest that habituation of neuroimmune responses to stress proceeds: (i) independent of HPA axis habituation; (ii) likely requires more daily sessions of stress to develop; and (iii) IL-1ß displays a greater tendency to habituate after repeated stress challenges compared to other stress-reactive cytokines.

Assembling patchy nanorods with spheres: limitations imposed by colloidal interactions.

For gold nanorods the intrinsic shape-anisotropy offers the prospect of anisotropic assembly, provided that their region-selective surface modification can be realized. Here we developed nanorods with a patchy surface chemistry, featuring positively charged molecules in the tip region and polymer molecules at the sides by careful control of molecule concentrations during ligand exchange. When these patchy nanorods are assembled with small negatively charged spherical particles, electric double layer interaction can direct the assembly of two nanospheres at the opposite ends of the nanorods. The PEG chains promote the selectivity of the procedure. As the size of the nanospheres increases, they start to shift towards the side of the nanorod due to increased van der Waals interaction. When the relative size of the nanospheres is even larger, only a single nanosphere is assembled, but instead of the tip region, they are attached to the side of the nanorods. The apparent cross-over of the region-selectivity can be interpreted in terms of colloidal interactions, i.e. the second spherical particle is excluded due to nanosphere-nanosphere electric double layer repulsion, while the large vdW attraction results in a side positioning of the single adsorbed spherical particle. The results underline the importance of absolute values of the different interaction strengths and length scales in the programmed assembly of patchy nanoscale building blocks.

Novel aspects of glucocorticoid actions.

Normal hypothalamic-pituitary-adrenal (HPA) axis activity leading to the rhythmic and episodic release of adrenal glucocorticoids (GCs) is essential for body homeostasis and survival during stress. Acting through specific intracellular receptors in the brain and periphery, GCs regulate behaviour, as well as metabolic, cardiovascular, immune and neuroendocrine activities. By contrast to chronic elevated levels, circadian and acute stress-induced increases in GCs are necessary for hippocampal neuronal survival and memory acquisition and consolidation, as a result of the inhibition of apoptosis, the facilitation of glutamatergic neurotransmission and the formation of excitatory synapses, and the induction of immediate early genes and dendritic spine formation. In addition to metabolic actions leading to increased energy availability, GCs have profound effects on feeding behaviour, mainly via the modulation of orexigenic and anorixegenic neuropeptides. Evidence is also emerging that, in addition to the recognised immune suppressive actions of GCs by counteracting adrenergic pro-inflammatory actions, circadian elevations have priming effects in the immune system, potentiating acute defensive responses. In addition, negative-feedback by GCs involves multiple mechanisms leading to limited HPA axis activation and prevention of the deleterious effects of excessive GC production. Adequate GC secretion to meet body demands is tightly regulated by a complex neural circuitry controlling hypothalamic corticotrophin-releasing hormone (CRH) and vasopressin secretion, which are the main regulators of pituitary adrenocorticotrophic hormone (ACTH). Rapid feedback mechanisms, likely involving nongenomic actions of GCs, mediate the immediate inhibition of hypothalamic CRH and ACTH secretion, whereas intermediate and delayed mechanisms mediated by genomic actions involve the modulation of limbic circuitry and peripheral metabolic messengers. Consistent with their key adaptive roles, HPA axis components are evolutionarily conserved, being present in the earliest vertebrates. An understanding of these basic mechanisms may lead to novel approaches for the development of diagnostic and therapeutic tools for disorders related to stress and alterations of GC secretion.

Oxytocin and vasopressin in the medial amygdala differentially modulate approach and avoidance behavior toward illness-related social odor.

Animals are known to recognize a specific odorant informing conspecific health condition, which plays a significant role in regulating their social communication. Here, we assess neural mechanisms regulating innate approach/avoidance response toward such conspecific odor cues in rats. Odor scent from healthy conspecifics induced approach behavior, while those from sick conspecifics produced avoidance response in odor-recipient male rats. Analysis of mRNA expression in several brain sites of odor recipient rats illustrated that induction of c-fos mRNA expression was found in the olfactory bulb (OB), the medial amygdala (MeA), the bed nucleus of stria terminalis (BnST), and the paraventricular nucleus of the hypothalamus (PVN), when exposed to conspecific odor. Moreover, in the MeA, expression of oxytocin (OT) receptor mRNA was increased when rats were exposed to healthy conspecific odor, while induction of arginine vasopressin (AVP) receptor 1a and 1b mRNA were found only when exposed to sick conspecific odor. Bilateral infusion of OT receptor (OTR) antagonist, (d(CH2)5(1),Tyr(Me)(2),Thr(4),Orn(8),des-Gly-NH2(9))-Vasotocin, into the MeA blocked approach behavior to healthy odor, while those of AVP receptor antagonists, V1a selective: (Phenylac(1),D-Tyr(Me)(2),Arg(6.8),Lys-NH2(9))-Vasopressin, and type 1 receptor antagonist: (Deamino-Pen(1), Try(Me)(2), Arg(8))-Vasopressin, into the MeA inhibited avoidance response to sick odor. These findings provide evidence for an essential role of OT and AVP receptors, especially type 1a, in the MeA in regulating approach/avoidance behaviors, respectively, in social odorant communication.

Exogenous corticosterone reduces L-DOPA-induced dyskinesia in the hemi-parkinsonian rat: role for interleukin-1beta.

While the etiology of Parkinson's disease (PD) remains unknown, there is overwhelming evidence that neuroinflammation plays a critical role in the progressive loss of dopamine (DA) neurons. Because nearly all persons suffering from PD receive l-DOPA, it is surprising that inflammation has not been examined as a potential contributor to the abnormal involuntary movements (AIMs) that occur as a consequence of chronic l-DOPA treatment. As an initial test of this hypothesis, we examined the effects of exogenously administered corticosterone (CORT), an endogenous anti-inflammatory agent, on the expression and development of l-DOPA-induced dyskinesia (LID) in unilateral DA-depleted rats. To do this, male Sprague-Dawley rats received unilateral medial forebrain bundle 6-hydroxydopamine lesions. Three weeks later, l-DOPA primed rats received acute injections of CORT (0-3.75 mg/kg) prior to l-DOPA to assess the expression of LID. A second group of rats was used to examine the development of LID in l-DOPA naïve rats co-treated with CORT and l-DOPA for 2 weeks. AIMs and rotations were recorded. Exogenous CORT dose-dependently attenuated both the expression and development of AIMs without affecting rotations. Real-time reverse-transcription polymerase chain reaction of striatal tissue implicated a role for interleukin-1 (IL-1) beta in these effects as its expression was increased on the lesioned side in rats treated with l-DOPA (within the DA-depleted striatum) and attenuated with CORT. In the final experiment, interleukin-1 receptor antagonist (IL-1ra) was microinjected into the striatum of l-DOPA-primed rats to assess the impact of IL-1 signaling on LID. Intrastriatal IL-1ra reduced the expression of LID without affecting rotations. These findings indicate a novel role for neuroinflammation in the expression of LID, and may implicate the use of anti-inflammatory agents as a potential adjunctive therapy for the treatment of LID.

Adaptation in the corticosterone and hyperthermic responses to stress following repeated stressor exposure.

Previous studies have shown that repeated daily exposure to the same (homotypic) stressor results in habituation of the corticosterone (CORT) response. Others have found that the stress response to a more ethologically relevant stressor, social defeat, does not habituate and, in some cases, sensitisation has been observed. Similar observations have been noted when core temperature is examined. Although habituation and/or sensitisation have been reported during stressor exposure, little is known about the development of an anticipatory fever in response to daily stressor exposure. The aim of the present study was to compare systematically commonly used laboratory stressors (i.e. restraint, cage confinement and social defeat) using a common set of procedures and analyses. Specifically, we examined: (i) the development of an anticipatory fever to repeated (5 days) homotypic stressor exposure; (ii) the adaptation of the fever response during stressor exposure; and (iii) the resolution of the fever response to stressors presented at the same time each day. For comparison, adaptation of the CORT response was also examined to assess the degree to which habituation to repeated stressor exposure may represent a more general response observed across diverse physiological measures. Habituation was observed after restraint and cage confinement, but not observed in either the CORT or hyperthermic responses to repeated social defeat. Furthermore, no anticipatory fever response was observed with repeated exposure to restraint, cage confinement, or social defeat. These data suggest that habituation to repeated stressor exposure may not occur with all homotypic stressor paradigms. In addition, rats do not appear to entrain an anticipatory fever response to a stressor presented at the same time each day, at least not within 5-6 days of repeated exposure.

An inter-laboratory evaluation of selective media for the detection and enumeration of yeasts from blue-veined cheese.

Five countries representative of laboratories 1-5 evaluated 11 different selective media, designed to suppress mould and bacterial growth and support yeasts growth, for the recovery of yeast populations from blue veined cheeses. In addition, qualitative results were also incorporated. The yeast enumeration values were subjected to statistical analysis using analysis of variance (ANOVA) and the Tukey-Kramer multiple comparison test. With the exception of Laboratory 3, none of the other laboratories was successful in recovering yeasts on all the media. Six of the media proved inadequate for the enumeration of yeasts in the mould invested environment and were therefore omitted from statistical analysis. No significant differences in quantitative data obtained on Rose-Bengal Chloramphenicol Agar (RBCA), Dichloran Rose-Bengal Chloramphenicol Agar (DRBC), Dichloran 18% Glycerol Agar (DG18), and Malt extract agar supplemented with NaCl and oxytetracycline (MES) were detected by four of the collaborating laboratories whereas one laboratory found RBCA to be superior for yeast enumeration. DG18 and Malt Extract Agar with Biphenyl (MEB), however, were ranked superior based on qualitative results compared to the other media, attributed to distinctive individual yeast colonies and mould inhibition. RBCA, DRBC, DG18, and MES on the other hand, all proved to be adequate in supporting yeast colony development for quantitative analysis in samples obtained from blue veined cheeses.

Characterization of yeast isolates originating from Hungarian dairy products using traditional and molecular identification techniques.

Yeast isolates collected from various Hungarian dairy products were identified using simplified identification system (SIM) and restriction fragment analysis of PCR-amplified 18S rDNA with the neighbouring ITS1 region (ITS-PCR; ribotyping). The isolates were grouped into 26 species; Geotrichum candidum, Debaryomyces hansenii, Yarrowia lipolytica, Kluyveromyces lactis and Candida catenulata were found as the predominant species. SIM and ITS-PCR proved to be useful and convenient taxonomic tools for rapid identification at species level. Two most frequent species, G. candidum and D. hansenii, were further characterized by randomly amplified polymorphic DNA (RAPD-PCR) analysis. RAPD-PCR using M13 primer resulted in discrimination between most strains of the same species and allowed a certain degree of intraspecific typing.

Blockade of alpha1 adrenoreceptors in the dorsal raphe nucleus prevents enhanced conditioned fear and impaired escape performance following uncontrollable stressor exposure in rats.

Previous research has shown that the effect of exposure to uncontrollable stressors on conditioned fear responding and escape behavior in rats is dependent on serotonergic neural activity in the dorsal raphe nucleus (DRN). The role that norepinephrine released in the DRN plays in producing the behavioral consequences of exposure to inescapable tail shock in rats was investigated in the present study. The selective alpha1 adrenoreceptor antagonist benoxathian was injected into the DRN before exposure to inescapable tail shock or before behavioral testing conducted 24 h later. Benoxathian prevented the impairment of escape responding produced by inescapable shock, but did not reverse this effect when given before testing. The enhancement of conditioned fear produced by prior inescapable shock was attenuated by benoxathian administered before inescapable shock or before behavioral testing. These results support the view that noradrenergic input to the DRN is necessary to produce the behavioral effects of inescapable tail shock.

Stress-induced sickness behaviors: an alternative hypothesis for responses during maternal separation.

During maternal separation, some primate and nonprimate species show a biphasic (active/passive) response. The second stage is characterized by reduced activity, a hunched body posture, and other behaviors. Traditionally, the second stage has been referred to as "despair" and is considered an animal model for human depression. Recent research in psychoneuroimmunology suggests an alternative hypothesis--that behaviors occurring during the second passive phase represent stress-induced "sickness behaviors." This perspective more readily accounts for findings in widely divergent species, does not require assumptions regarding the ability to express complex emotional states, is empirically testable, and aligns the separation model with recent hypotheses regarding the nature and ontogeny of depressive illness.

Comparison of dichloran 18% glycerol (DG18) agar with general purpose mycological media for enumerating food spoilage yeasts.

Dichloran 18% glycerol (DG18) agar was originally developed to enumerate xerophilic foodborne moulds. However, some laboratories are using DG18 agar as a general medium to enumerate foodborne moulds and yeasts. A collaborative study, with the participation of seven laboratories, was undertaken to compare DG18 agar with dichloran rose bengal chloramphenicol (DRBC) agar, tryptone glucose yeast extract chloramphenicol (TGYC) agar, and plate count agar supplemented with chloramphenicol (PCAC) for enumerating 14 species of common food spoilage yeasts. Comparison of the mean values of populations of all yeasts recovered on each medium revealed no significant differences among DRBC agar, PCAC, and TGYC agar, while each of these media supported the development of significantly (P < or = 0.05) higher numbers of colonies than DG18 agar. However, differences were only 0.08 to 0.10 log10 cfu/ml, making the practical significance questionable. The overall coefficient of variation (CV) for within laboratory repeatability was 1.71%, while the CV for reproducibility of counts obtained among laboratories was 6.96%. Compared to DRBC agar, TGYC agar, and PCAC, yeast colonies were smaller on DG18 agar. Growth of Brettanomyces anomalus, Cryptococcus albidus, and Rhodotorula mucilaginosa was particularly retarded or inhibited on DG18 agar. Based on the performance of media in supporting colony development and ease of counting colonies, the use of DG18 agar as a general enumeration medium for foodborne yeasts cannot be recommended.

Identification of yeasts isolated from poultry meat.

In an assessment of the potential role of yeasts in the spoilage of poultry meat, the population and species diversity of yeasts were determined on 50 commercial raw and processed chicken and turkey product samples. Initial populations (log10 cfu/g) ranged from less than 0.1 to 2.9, and increased by the expiration date to 0.4 to 5.1, respectively. 145 of 152 isolates were identified as belonging to 12 species. Yarrowia lipolytica and Candida zeylanoides were predominant, accounting for 39% and 26% of the isolates, respectively. Six different species of basidiomycetous yeasts were determined representing 24% of the isolates. The ability of the predominant yeast species to grow at refrigeration temperatures and their proteolytic and lipolytic activies suggest that yeasts may play a more significant role than previously recognised in the spoilage of poultry products.

Endogenous glucocorticoids play a positive regulatory role in the anti-keyhole limpet hemocyanin in vivo antibody response.

Glucocorticoids (GCs) are commonly reported to be immunosuppressive. Studies that support this involve the administration of synthetic GCs such as dexamethasone at high pharmacological doses and using in vitro assay systems that may have limited relevance to the role of GCs during normal in vivo immune responses. Therefore, the following experiments tested the conclusion that GCs are generally immunosuppressive. Adult male Sprague Dawley rats received adrenalectomy (ADX) or sham surgery. ADX rats were given either basal corticosterone (CORT) replacement in their drinking water (25 microg/ml) or no CORT. Rats were immunized with keyhole limpet hemocyanin (KLH), and blood samples were taken. ADX rats with no CORT replacement had reduced anti-KLH IgM and IgG responses compared with sham-operated controls. ADX rats that received basal CORT replacement had partially restored anti-KLH IgM, but still had suppressed anti-KLH IgG. Administration of GC receptor type I (RU28318) and type II (RU40555) receptor antagonists also reduced the anti-KLH IgM and IgG responses. ADX rats that received both basal CORT replacement and low dose injections of CORT on days 5 and 7 after KLH had anti-KLH IgG levels equal to those of sham-operated controls. Finally, the GC elevation 4-7 days after immunization may play a role in stimulating the IgM to IgG2a switch. GC receptor blockade reduced the anti-KLH IgG2a and splenic IFN-gamma, but not the anti-KLH IgG1, response. Given that IFN-gamma is an important regulator of the IgM to IgG2a switch, it is possible that the small rise in GC found 4-7 days after KLH facilitates IgG2a isotype switching.

Performance of mycological media in enumerating desiccated food spoilage yeasts: an interlaboratory study.

Dichloran 18% glycerol agar (DG18) was originally formulated to enumerate nonfastidious xerophilic moulds in foods containing rapidly growing Eurotium species. Some laboratories are now using DG18 as a general purpose medium for enumerating yeasts and moulds, although its performance in recovering yeasts from dry foods has not been evaluated. An interlaboratory study compared DG18 with dichloran rose bengal chloramphenicol agar (DRBC), plate count agar supplemented with chloramphenicol (PCAC), tryptone glucose yeast extract chloramphenicol agar (TGYC), acidified potato dextrose agar (APDA), and orange serum agar (OSA) for their suitability to enumerate 14 species of lyophilized yeasts. The coefficient of variation for among-laboratories repeatability within yeast was 1.39% and reproducibility of counts among laboratories was 7.1%. The order of performance of media for recovering yeasts was TGYC > PCAC = OSA > APDA > DRBC > DG 18. A second study was done to determine the combined effects of storage time and temperature on viability of yeasts and suitability of media for recovery. Higher viability was retained at -18 degrees C than at 5 degrees C or 25 degrees C for up to 42 weeks, although the difference in mean counts of yeasts stored at -18 degrees C and 25 degrees C was only 0.78 log10 cfu/ml of rehydrated suspension. TGYC was equal to PCAC and superior to the other four media in recovering yeasts stored at -18 degrees C, 5 degrees C, or 25 degrees C for up to 42 weeks. Results from both the interlaboratory study and the storage study support the use of TGYC for enumerating desiccated yeasts. DG18 is not recommended as a general purpose medium for recovering yeasts from a desiccated condition.

Treadmill running produces both positive and negative physiological adaptations in Sprague-Dawley rats.

Exercise training produces a vast array of physiological adaptations, ranging from changes in metabolism to muscle mitochondrial biogenesis. Researchers studying the physiological effects of exercise often use animal models that employ forced exercise regimens that include aversive motivation, which could activate the stress response. This study examined the effect of forced treadmill running (8 wk) on several physiological systems that are sensitive to training and stress. Forced treadmill running produced both positive and negative physiological adaptations. Indicative of positive training adaptations, exercised male Sprague-Dawley rats had a decrease in body weight gain and an increase in muscle citrate synthase activity compared with sedentary controls. In contrast, treadmill running also resulted in the potentially negative adaptations of adrenal hypertrophy, thymic involution, decreased serum corticosteroid binding globulin, elevated lymphocyte nitrite concentrations, suppressed lymphocyte proliferation, and suppressed antigen-specific IgM. Such alterations in neuroendocrine tissues and immune responses are commonly associated with chronic stress. Thus treadmill running produces both positive training adaptations and potentially negative adaptations that are indicative of chronic stress. Researchers employing forced activity need to be aware that this type of exercise procedure also produces physiological adaptations indicative of chronic stress and that these changes could potentially impact other measures of interest.

Molecular characterization of Yarrowia lipolytica and Candida zeylanoides isolated from poultry.

Yeast isolates from raw and processed poultry products were characterized using PCR amplification of the internally transcribed spacer (ITS) 5.8S ribosomal DNA region (ITS-PCR), restriction analysis of amplified products, randomly amplified polymorphic DNA (RAPD) analysis, and pulsed-field gel electrophoresis (PFGE). ITS-PCR resulted in single fragments of 350 and 650 bp, respectively, from eight strains of Yarrowia lipolytica and seven strains of Candida zeylanoides. Digestion of amplicons with HinfI and HaeIII produced two fragments of 200 and 150 bp from Y. lipolytica and three fragments of 350, 150, and 100 bp from C. zeylanoides, respectively. Although these fragments showed species-specific patterns and confirmed species identification, characterization did not enable intraspecies typing. Contour-clamped heterogeneous electric field PFGE separated chromosomal DNA of Y. lipolytica into three to five bands, most larger than 2 Mbp, whereas six to eight bands in the range of 750 to 2,200 bp were obtained from C. zeylanoides. Karyotypes of both yeasts showed different polymorphic patterns among strains. RAPD analysis, using enterobacterial repetitive intergenic sequences as primers, discriminated between strains within the same species. Cluster analysis of patterns formed groups that correlated with the source of isolation. For ITS-PCR, extraction of DNA by boiling yeast cells was successfully used.