Characterizing the ribosomal tandem repeat and its utility as a DNA barcode in lichen-forming fungi.

BACKGROUND: Regions within the nuclear ribosomal operon are a major tool for inferring evolutionary relationships and investigating diversity in fungi. In spite of the prevalent use of ribosomal markers in fungal research, central features of nuclear ribosomal DNA (nrDNA) evolution are poorly characterized for fungi in general, including lichenized fungi. The internal transcribed spacer (ITS) region of the nrDNA has been adopted as the primary DNA barcode identification marker for fungi. However, little is known about intragenomic variation in the nrDNA in symbiotic fungi. In order to better understand evolution of nrDNA and the utility of the ITS region for barcode identification of lichen-forming fungal species, we generated nearly complete nuclear ribosomal operon sequences from nine species in the Rhizoplaca melanophthalma species complex using short reads from high-throughput sequencing. RESULTS: We estimated copy numbers for the nrDNA operon, ranging from nine to 48 copies for members of this complex, and found low levels of intragenomic variation in the standard barcode region (ITS). Monophyly of currently described species in this complex was supported in phylogenetic inferences based on the ITS, 28S, intergenic spacer region, and some intronic regions, independently; however, a phylogenetic inference based on the 18S provided much lower resolution. Phylogenetic analysis of concatenated ITS and intergenic spacer sequence data generated from 496 specimens collected worldwide revealed previously unrecognized lineages in the nrDNA phylogeny. CONCLUSIONS: The results from our study support the general assumption that the ITS region of the nrDNA is an effective barcoding marker for fungi. For the R. melanophthalma group, the limited amount of potential intragenomic variability in the ITS region did not correspond to fixed diagnostic nucleotide position characters separating taxa within this species complex. Previously unrecognized lineages inferred from ITS sequence data may represent undescribed species-level lineages or reflect uncharacterized aspects of nrDNA evolution in the R. melanophthalma species complex.

Formally described species woefully underrepresent phylogenetic diversity in the common lichen photobiont genus Trebouxia (Trebouxiophyceae, Chlorophyta): An impetus for developing an integrated taxonomy.

Lichens provide valuable systems for studying symbiotic interactions. In lichens, these interactions are frequently described in terms of availability, selectivity and specificity of the mycobionts and photobionts towards one another. The lichen-forming, green algal genus Trebouxia Puymaly is among the most widespread photobiont, associating with a broad range of lichen-forming fungi. To date, 29 species have been described, but studies consistently indicate that the vast majority of species-level lineages still lack formal description, and new, previously unrecognized lineages are frequently reported. To reappraise the diversity and the evolutionary relationships of species-level lineages in Trebouxia, we assembled DNA sequence data from over 1600 specimens, compiled from a range of sequences from previously published studies, axenic algal cultures, and lichens collected from poorly sampled regions. From these samples, we selected representatives of the currently known genetic diversity in the lichenized Trebouxia and inferred a phylogeny from multi-locus sequence data (ITS, rbcL, cox2). We demonstrate that the current formally described species woefully underrepresent overall species-level diversity in this important lichen-forming algal genus. We anticipate that an integrative taxonomic approach, incorporating morphological and physiological data from axenic cultures with genetic data, will be required to establish a robust, comprehensive taxonomy for Trebouxia. The data presented here provide an important impetus and reference dataset for more reliably characterizing diversity in lichenized algae and in using lichens to investigate the evolution of symbioses and holobionts.

Cophylogenetic patterns in algal symbionts correlate with repeated symbiont switches during diversification and geographic expansion of lichen-forming fungi in the genus Sticta (Ascomycota, Peltigeraceae).

Species in the fungal genus Sticta form symbiotic associations primarily with either green algae or cyanobacteria, but tripartite associations or photosymbiodemes involving both types of photobionts occur in some species. Sticta is known to associate with green algae in the genus Symbiochloris. However, previous studies have shown that algae from other genera, such as Heveochlorella, may also be suitable partners for Sticta. We examined the diversity of green algal partners in the genus Sticta and assessed the patterns of association between the host fungus and its algal symbiont. We used multi-locus sequence data from multiple individuals collected in Australia, Cuba, Madagascar, Mauritius, New Zealand, Reunion and South America to infer phylogenies for fungal and algal partners and performed tests of congruence to assess coevolution between the partners. In addition, event-based methods were implemented to examine which cophylogenetic processes have led to the observed association patterns in Sticta and its green algal symbionts. Our results show that in addition to Symbiochloris, Sticta associates with green algae from the genera Chloroidium, Coccomyxa, Elliptochloris and Heveochlorella, the latter being the most common algal symbiont associated with Sticta in this study. Geography plays a strong role in shaping fungal-algal association patterns in Sticta as mycobionts associate with different algal lineages in different geographic locations. While fungal and algal phylogenies were mostly congruent, event-based methods did not find any evidence for cospeciation between the partners. Instead, the association patterns observed in Sticta and associated algae, were largely explained by other cophylogenetic events such as host-switches, losses of symbiont and failure of the symbiont to diverge with its host. Our results also show that tripartite associations with green algae evolved multiple times in Sticta.

Rodent models of impulsive-compulsive behaviors in Parkinson's disease: How far have we reached?

There is increasing awareness that the medications used to treat the motor symptoms of Parkinson's disease (PD) contribute to the development of behavioral addictions, which have been clinically defined as impulsive-compulsive behaviors (ICBs). These features include pathological gambling, compulsive sexual behavior, binge eating, compulsive shopping, excessive hobbyism or punding, and the excessive use of dopaminergic medication. ICBs frequently have devastating effects on the social and occupational function of the affected individuals as well as their families. Although ICBs are an important clinical problem in PD, the number of studies in which these symptoms have been modeled in rodents is still limited. This may depend on uncertainties regarding, on one hand, the pathophysiology of these behaviors and, on the other hand, the experimental paradigms with which similar features can be induced in rodents. To help compose these uncertainties, we will here review the characteristics of ICBs in PD patients and then describe behavioral methods to approximate them in rodents. We will discuss both the challenges and the possibilities of applying these methods to animals with PD-like lesions, and review the recent progress made to this end. We will finally highlight important questions deserving further investigation. Rodent models having both face validity and construct validity to parkinsonian ICBs will be essential to further pathophysiological and therapeutic studies into this important area.

Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi.

We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.

Impaired cognitive and motor function are coincident with L-DOPA-induced dyskinesia in a model of Parkinson's disease.

Dopamine transmission has been implicated in motor and cognitive function. In Parkinson's disease (PD), dopamine replacement using the precursor drug L-DOPA is the predominant treatment approach, but long-term exposure leads to the onset of dyskinesias (LIDs). Chronic L-DOPA exposure has been associated with changes in gene expression and altered cortico-striatal plasticity. The aim of this research was to assess the functional consequence of long-term L-DOPA exposure on cognitive and motor function using a rodent model of PD. Across two independent experiments, we assessed the impact of chronic L-DOPA exposure, or a control D2R agonist, on motor and cognitive function in intact and in hemi parkinsonian rats, in the absence of drug. Abnormal involuntary movements associated with LID were measured and brain tissues were subsequently harvested for immunohistochemical analysis. Exposure to chronic L-DOPA, but not the D2R agonist, impaired motor and cognitive function, when animals were tested in the absence of drug. A meta-analysis of the two experiments allowed further dissociation of L-DOPA -treated rats into those that developed LIDs (dyskinetic) and those that did not develop LIDs (non-dyskinetic). This analysis revealed impaired cognitive and motor performance were evident only in dyskinetic, but not in non-dyskinetic, rats. These data reveal a functional consequence of the altered plasticity associated with LID onset and have implications for understanding symptom progression in the clinic.

Effort-related effects of chronic administration of the DA D2 receptor antagonist haloperidol via subcutaneous programmable minipumps: Reversal by co-administration of the adenosine A2A antagonist istradefylline.

RATIONALE: Long-acting antipsychotics such as haloperidol decanoate are becoming more commonly used. Long-acting depot formulations have several advantages, but secondary negative effects of prolonged delivery, including motivational dysfunctions, could have debilitating effects. Assessing the behavioral changes that emerge during chronic antipsychotic administration in rats could provide insight regarding the development of motivational dysfunctions and drug tolerance. OBJECTIVES: Acute administration of dopamine D2 antagonists such as haloperidol induce motivational deficits in rats, as marked by a shift towards a low-effort bias during effort-based choice tasks. In the present studies, programmable subcutaneous infusion pumps provided continuous and controlled drug delivery of haloperidol. Animals were assessed using a fixed ratio (FR) 5 lever pressing schedule and the FR5/chow feeding test of effort-based choice. The adenosine A2A antagonist istradefylline was studied for its ability to reverse the effects of chronic haloperidol. RESULTS: Continuous chronic infusions of haloperidol produced significant reductions in FR5 performance and a shift from lever pressing to chow intake in rats tested on FR5/chow feeding choice, with no evidence of tolerance over the 4-week infusion period. Behavior returned to baseline during the vehicle-infusion washout period. Istradefylline significantly reversed the effects of haloperidol, increasing lever pressing and decreasing chow intake in haloperidol-treated rats. CONCLUSIONS: These studies provide an important behavioral characterization of the effects of chronically infused haloperidol, and demonstrate that A2A antagonism reverses the effects of chronic haloperidol. This research could contribute to the understanding and treatment of motivational dysfunctions seen in schizophrenia, Parkinson's disease, and other disorders involving dopamine.

Cognitive dysfunction and depression in Parkinson's disease: what can be learned from rodent models?

Parkinson's disease (PD) has for decades been considered a pure motor disorder and its cardinal motor symptoms have been attributed to the loss of dopaminergic (DAergic) neurons in the substantia nigra pars compacta and to nigral Lewy body pathology. However, there has more recently been a shift in the conceptualization of the disease, and its pathological features have now been recognized as involving several other areas of the brain and indeed even outside the central nervous system. There are a corresponding variety of intrinsic non-motor symptoms such as autonomic dysfunction, cognitive impairment, sleep disturbances and neuropsychiatric problems, which cannot be explained exclusively by nigral pathology. In this review, we will focus on cognitive impairment and affective symptoms in PD, and we will consider whether, and how, these deficits can best be modelled in rodent models of the disorder. As only a few of the non-motor symptoms respond to standard DA replacement therapies, the quest for a broader therapeutic approach remains a major research effort, and success in this area in particular will be strongly dependent on appropriate rodent models. In addition, better understanding of the different models, as well as the advantages and disadvantages of the available behavioural tasks, will result in better tools for evaluating new treatment strategies for PD patients suffering from these neuropsychological symptoms.

Vascular endothelial growth factor is upregulated by L-dopa in the parkinsonian brain: implications for the development of dyskinesia.

Angiogenesis and increased permeability of the blood-brain barrier have been reported to occur in animal models of Parkinson's disease and l-dopa-induced dyskinesia, but the significance of these phenomena has remained unclear. Using a validated rat model of l-dopa-induced dyskinesia, this study demonstrates that chronic treatment with l-dopa dose dependently induces the expression of vascular endothelial growth factor in the basal ganglia nuclei. Vascular endothelial growth factor was abundantly expressed in astrocytes and astrocytic processes in the proximity of blood vessels. When co-administered with l-dopa, a small molecule inhibitor of vascular endothelial growth factor signalling significantly attenuated the development of dyskinesia and completely blocked the angiogenic response and associated increase in blood-brain barrier permeability induced by the treatment. The occurrence of angiogenesis and vascular endothelial growth factor upregulation was verified in post-mortem basal ganglia tissue from patients with Parkinson's disease with a history of dyskinesia, who exhibited increased microvascular density, microvascular nestin expression and an upregulation of vascular endothelial growth factor messenger ribonucleic acid. These congruent findings in the rat model and human patients indicate that vascular endothelial growth factor is implicated in the pathophysiology of l-dopa-induced dyskinesia and emphasize an involvement of the microvascular compartment in the adverse effects of l-dopa pharmacotherapy in Parkinson's disease.

Genome-Wide Association Studies across Environmental and Genetic Contexts Reveal Complex Genetic Architecture of Symbiotic Extended Phenotypes.

A goal of modern biology is to develop the genotype-phenotype (G→P) map, a predictive understanding of how genomic information generates trait variation that forms the basis of both natural and managed communities. As microbiome research advances, however, it has become clear that many of these traits are symbiotic extended phenotypes, being governed by genetic variation encoded not only by the host's own genome, but also by the genomes of myriad cryptic symbionts. Building a reliable G→P map therefore requires accounting for the multitude of interacting genes and even genomes involved in symbiosis. Here, we use naturally occurring genetic variation in 191 strains of the model microbial symbiont Sinorhizobium meliloti paired with two genotypes of the host Medicago truncatula in four genome-wide association studies (GWAS) to determine the genomic architecture of a key symbiotic extended phenotype-partner quality, or the fitness benefit conferred to a host by a particular symbiont genotype, within and across environmental contexts and host genotypes. We define three novel categories of loci in rhizobium genomes that must be accounted for if we want to build a reliable G→P map of partner quality; namely, (i) loci whose identities depend on the environment, (ii) those that depend on the host genotype with which rhizobia interact, and (iii) universal loci that are likely important in all or most environments. IMPORTANCE Given the rapid rise of research on how microbiomes can be harnessed to improve host health, understanding the contribution of microbial genetic variation to host phenotypic variation is pressing, and will better enable us to predict the evolution of (and select more precisely for) symbiotic extended phenotypes that impact host health. We uncover extensive context-dependency in both the identity and functions of symbiont loci that control host growth, which makes predicting the genes and pathways important for determining symbiotic outcomes under different conditions more challenging. Despite this context-dependency, we also resolve a core set of universal loci that are likely important in all or most environments, and thus, serve as excellent targets both for genetic engineering and future coevolutionary studies of symbiosis.

L-DOPA-induced dopamine efflux in the striatum and the substantia nigra in a rat model of Parkinson's disease: temporal and quantitative relationship to the expression of dyskinesia.

L-DOPA-induced dyskinesia in Parkinson's disease is associated with large increases in brain dopamine (DA) levels following drug dosing, but the precise significance of this phenomenon is not understood. Here we compare DA efflux and metabolism in the striatum and the substantia nigra in dyskinetic and non-dyskinetic animals following a standard dose of L-DOPA. Rats with 6-hydroxydopamine lesions were treated chronically with L-DOPA, monitored on the abnormal involuntary movements scale, and then subjected to intracerebral microdialysis under freely-moving conditions. Following s.c. L-DOPA injection, peak extracellular DA levels in both striatum and substantia nigra were about twice as large in dyskinetic animals compared to non-dyskinetic rats. This effect was not attributable to differences in DOPA levels or DA metabolism. The larger DA efflux in dyskinetic animals was blunted by 5-HT1A/5-HT1B receptor agonists and tetrodotoxin infusion, reflecting release from serotonin neurons. Striatal levels of serotonin and its main metabolite, 5-hydroxyindolacetic acid were indeed elevated in dyskinetic animals compared to non-dyskinetic rats, indicating a larger serotonergic innervation density in the former group. High DA release was, however, not sufficient to explain dyskinesia. The 'abnormal involuntary movements output' per unit concentration of striatal extracellular DA was indeed much larger in dyskinetic animals compared to non-dyskinetic cases at most time points examined. The present results indicate that both a high DA release post-L-DOPA administration and an increased responsiveness to DA must coexist for a full expression of dyskinesia.

Characterization of Amphetamine, Methylphenidate, Nicotine, and Atomoxetine on Measures of Attention, Impulsive Action, and Motivation in the Rat: Implications for Translational Research.

Amphetamine (AMP), methylphenidate (MPH), and atomoxetine (ATX) are approved treatments for ADHD, and together with nicotine (NIC), represent pharmacological agents widely studied on cognitive domains including attention and impulsive action in humans. These agents thus represent opportunities for clinical observation to be reinvestigated in the preclinical setting, i.e., reverse translation. The present study investigated each drug in male, Long Evans rats trained to perform either (1) the five-choice serial reaction time task (5-CSRTT), (2) Go/NoGo task, or (3) a progressive ratio (PR) task, for the purpose of studying each drug on attention, impulsive action and motivation. Specific challenges were adopted in the 5-CSRTT designed to tax attention and impulsivity, i.e., high frequency of stimulus presentation (sITI), variable reduction in stimulus duration (sSD), and extended delay to stimulus presentation (10-s ITI). Initially, performance of a large (> 80) cohort of rats in each task variant was conducted to examine performance stability over repeated challenge sessions, and to identify subgroups of "high" and "low" attentive rats (sITI and sSD schedules), and "high" and "low" impulsives (10-s ITI). Using an adaptive sequential study design, the effects of AMP, MPH, ATX, and NIC were examined and contrasting profiles noted across the tests. Both AMP (0.03-0.3 mg/kg) and MPH (1-6 mg/kg) improved attentional performance in the sITI but not sSD or 10-s ITI condition, NIC (0.05-0.2 mg/kg) improved accuracy across all conditions. ATX (0.1-1 mg/kg) detrimentally affected performance in the sITI and sSD condition, notably in "high" performers. In tests of impulsive action, ATX reduced premature responses notably in the 10-s ITI condition, and also reduced false alarms in Go/NoGo. Both AMP and NIC increased premature responses in all task variants, although AMP reduced false alarms highlighting differences between these two measures of impulsive action. The effect of MPH was mixed and appeared baseline dependent. ATX reduced break point for food reinforcement suggesting a detrimental effect on motivation for primary reward. Taken together these studies highlight differences between AMP, MPH, and ATX which may translate to their clinical profiles. NIC had the most reliable effect on attentional accuracy, whereas ATX was reliably effective against all tests of impulsive action.

Endothelial proliferation and increased blood-brain barrier permeability in the basal ganglia in a rat model of 3,4-dihydroxyphenyl-L-alanine-induced dyskinesia.

3,4-Dihydroxyphenyl-L-alanine (L-DOPA)-induced dyskinesia is associated with molecular and synaptic plasticity in the basal ganglia, but the occurrence of structural remodeling through cell genesis has not been explored. In this study, rats with 6-hydroxydopamine lesions received injections of the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) concomitantly with L-DOPA for 2 weeks. A large number of BrdU-positive cells were found in the striatum and its output structures (globus pallidus, entopeduncular nucleus, and substantia nigra pars reticulata) in L-DOPA-treated rats that had developed dyskinesia. The vast majority (60-80%) of the newborn cells stained positively for endothelial markers. This endothelial proliferation was associated with an upregulation of immature endothelial markers (nestin) and a downregulation of endothelial barrier antigen on blood vessel walls. In addition, dyskinetic rats exhibited a significant increase in total blood vessel length and a visible extravasation of serum albumin in the two structures in which endothelial proliferation was most pronounced (substantia nigra pars reticulata and entopeduncular nucleus). The present study provides the first evidence of angiogenesis and blood-brain barrier dysfunction in an experimental model of L-DOPA-induced dyskinesia. These microvascular changes are likely to affect the kinetics of L-DOPA entry into the brain, favoring the occurrence of motor complications.

The "motor complication syndrome" in rats with 6-OHDA lesions treated chronically with L-DOPA: relation to dose and route of administration.

L-DOPA-induced motor complications can be modelled in rats with 6-hydroxydopamine (6-OHDA) lesions by chronic injections of L-DOPA. We have compared the sensitisation and duration of rotational responses, and the occurrence of dose-failure episodes and abnormal involuntary movements (AIMs) in 6-OHDA-lesioned rats with regard to the dose and route of administration of L-DOPA. Rats were treated with either low (6mg/kg) or high (25mg/kg) doses of L-DOPA twice daily for 21 days whereas control animals received injections of either saline or bromocriptine (2.5mg/kg). A dose-dependent and gradual development of AIMs and contralateral turning was observed in rats treated chronically with l-DOPA. Rats treated with bromocriptine exhibited rotational sensitisation but no AIMs. A shortening of motor response duration was not seen in any of the drug-treated groups. In contrast, dose-failure episodes occurred frequently in both L-DOPA- and bromocriptine-treated animals. Changing the route of L-DOPA administration from intraperitoneal to subcutaneous completely abolished failures in motor response without affecting the development of dyskinesia. Based on the hypothesis that higher doses of L-DOPA may be toxic to dopaminoceptive structures, we compared the total number of neurons and the levels of activated microglia in the striatum. No signs of neurodegenerative changes could be seen in any of the treatment groups. In conclusion, both body AIMs and rotations were dose-dependently evoked by L-DOPA. Only AIMs, however, provided a specific measure of dyskinesia since rotations also were induced by bromocriptine, a drug with low dyskinesiogenic potential. Dose-failure episodes were not specific to L-DOPA treatment and could be attributed to erratic drug absorption from the peritoneal route.

Corticosterone-induced inhibition of gliogenesis in rat hippocampus is counteracted by electroconvulsive seizures.

BACKGROUND: Volumetric changes and glial pathology have been reported in the central nervous system (CNS) of patients with depressive disorder, an illness often associated with elevated glucocorticoid levels. Glucocorticoids reduce gliogenesis in the adult rat CNS. Electroconvulsive seizure (ECS)-treatment, an animal model for the antidepressant treatment electroconvulsive therapy, can enhance proliferation of glial cells. This study examined glial cell proliferation in response to ECS in rats whose glucocorticoid levels were elevated to mimic the conditions seen in depression. METHODS: Rats were injected daily for seven days with either corticosterone or vehicle. ECS- or sham- treatment was given once daily during the first five days. Proliferating cells in the hippocampus were labeled with bromodeoxyuridine and analyzed for co-labeling with the glial cell markers NG2, Ox42, S-100beta and Rip. RESULTS: ECS counteracted the glucocorticoid-induced inhibition of NG2+, Ox42+ and Rip+ cell proliferation, and the gliogenesis rate was restored to baseline levels. Volumetric changes in rats treated with ECS were detected. CONCLUSIONS: Our results show that ECS-treatment affects the proliferation of glial cells even in the presence of elevated levels of glucocorticoids. This result adds to an increasing number of studies suggesting that antidepressant treatment can counteract degenerative processes associated with major depression.

Quinic acid is a biologically active component of the Uncaria tomentosa extract C-Med 100.

We have previously reported that the C-Med 100 extract of the plant Uncaria tomentosa induces prolonged lymphocyte half life and hence increased spleen cell number in mice receiving the extract in their drinking water. Further, the extract induces cell proliferation arrest and inhibits activation of the transcriptional regulator nuclear factor kappaB (NF-kappaB) in vitro. We now report that mice exposed to quinic acid (QA), a component of this extract, had significantly increased number of spleen cells, thus recapitulating the in vivo biological effect of C-Med 100 exposure. Commercially supplied QA (H(+) form) did not, however, inhibit cell proliferation in vitro, while the ammonia-treated QA (QAA) was a potent inhibitor. Both QA and QAA inhibited NF-kappaB activity in exposed cells at similar concentrations. Thus, our present data identify QA as a candidate component for both in vivo and in vitro biological effects of the C-Med 100 extract.

The phylogenetic analysis of fungi associated with lichenized ascomycete genus Bryoria reveals new lineages in the Tremellales including a new species Tremella huuskonenii hyperparasitic on Phacopsis huuskonenii.

The basidiomycete order Tremellales includes many species parasitic on or cohabiting with lichen-forming fungi. In this study, we examined the phylogenetic position of Tremellales obtained from Bryoria thalli using nSSU, 5.8S, and partial nLSU sequence data. Both Bayesian and maximum likelihood analyses revealed the presence of basidiomycetous fungi in three separate clades within Tremellales. Tremellales sp. A and Tremella sp. B exist asymptomatically in Bryoria thalli and should thus be regarded as endolichenic rather than lichenicolous fungi. The third lineage represents a new species and is described here as Tremella huuskonenii. It is hyperparasitic over galls induced by Phacopsis huuskonenii, a lichenicolous fungus growing in Bryoria thalli. We also examined the genetic diversity of Tremella sp. B and Tremella huuskonenii with an extended taxon sampling using ITS and partial nLSU sequence data. For comparison, ITS, GAPDH, and Mcm7 regions were used for phylogenetic analyses of the host lichen specimens. According to our results, phylogenetic structure within the two Tremella species does not appear to correlate with the geographic distribution nor with the phylogeny or the secondary chemistry of the host lichen. However, ITS haplotype analysis of T. huuskonenii revealed some genetic differences between European and North American populations as some haplotypes were more common in Europe than in North America and vice versa.

An extract of Uncaria tomentosa inhibiting cell division and NF-kappa B activity without inducing cell death.

Previous reports have demonstrated that extracts of the plant Uncaria tomentosa inhibit tumor cell proliferation and inflammatory responses. We have confirmed that C-Med 100, a hot water extract of this plant, inhibits tumor cell proliferation albeit with variable efficiency. We extend these findings by showing that this extract also inhibits proliferation of normal mouse T and B lymphocytes and that the inhibition is not caused by toxicity or by induction of apoptosis. Further, the extract did not interfere with IL-2 production nor IL-2 receptor signaling. Since there was no discrete cell cycle block in C-Med 100-treated cells, we propose that retarded cell cycle progression caused the inhibition of proliferation. Collectively, these data suggested interference with a common pathway controlling cell growth and cell cycle progression. Indeed, we provide direct evidence that C-Med 100 inhibits nuclear factor kappa B (NF-kappa B) activity and propose that this at least partially causes the inhibition of proliferation.

Nigral 6-hydroxydopamine lesion impairs performance in a lateralised choice reaction time task--impact of training and task parameters.

Unilateral intrastriatal and intra-medial forebrain bundle injections of 6-OHDA impair the performance in a lateralised choice reaction time task. However, the extent and pattern of deficits after nigral 6-OHDA injections is less well studied, as well as the impact of training regime or the modification of various task parameters. The nigral 6-OHDA lesion resulted in impaired response accuracy and an increased time to react to and execute the response on the side contralateral to the lesion as compared to sham-lesioned controls. Pre-training of the rats on the task prior to the lesion resulted in slightly faster reaction times as well as a reduced number of preservative panel presses compared to when rats were trained after the 6-OHDA injection. When the rat had to perform a longer sustained nose poke before responding to the lateralised stimuli, the number of useable trials was reduced in both controls and 6-OHDA rats as a result of an increased number of premature withdrawals from the centre hole. This study demonstrates that rats with a nigral 6-OHDA lesion display several distinct deficits in this operant task, which are similar to those seen after striatal and bundle 6-OHDA injections. In addition, by combining pre-training with the use of a short set of holds, improved sensitivity of this task can be achieved. This improvement in sensitivity may be of advantage when exploring new therapeutic interventions for PD, where subtle but relevant changes in performance may arise.

The effect of additional noradrenergic and serotonergic depletion on a lateralised choice reaction time task in rats with nigral 6-OHDA lesions.

Parkinson's disease (PD) patients often suffer from visuospatial deficits, which have been considered a disruption of the representation of external space. The lateralised choice reaction time (CRT) task is an operant task for rodents in which similar deficits can be assessed. It has been demonstrated that specific parameters in this task is disrupted after unilateral injections of 6-hydroxydopamine (6-OHDA), which have been associated with the dopamine (DA) depletion that inevitably follows this type of lesion. However, studies have demonstrated that this type of lesion also affects the serotonergic (5HT) and noradrenergic (NA) systems. However, the impact of these systems on parameters in the CRT task had not yet been investigated. To this end, rats were pretrained on the CRT task before receiving selective lesions of the DAergic system, either alone or in combination with depletion of the NA or 5HT system. All rats with a 6-OHDA lesion displayed a gradual decline in the selection, initiation and execution of lateralised movements compared to sham-lesion controls on the side contralateral to the lesion. They also displayed a reduced number of useable trials as well as an increased number of procedural errors. Interestingly, the group with an additional noradrenergic lesion was significantly slower in reacting to lateralised stimuli throughout the testing period compared to the other two groups with a 6-OHDA lesion. There was however no difference between the three different lesion groups in the other parameters assessed in the task. These data confirm previous findings demonstrating that the majority of the parameters assessed in the lateralised CRT task are strongly dependent on DA. However, this study has also shown that the NAergic system may play an important role in contributing to the attentive performance influencing the capacity to react to the presented lateralised stimuli.