Poster Sessions AP10: Learning,Memory and Behavior. S‐adenosylmethionine induced seizures are anesthetic dependant

S‐adenosylmethionine (SAMe) is present in all tissues and functions as the sole donor of methyl groups in over 100 different methylation reactions. Recent reports suggest that direct intraventricular injection of SAMe induces Parkinsonian like symptoms in rats including seizures, tremors, hyperkinesia and abnormal posture. In order to assess the influence of SAMe on rat behavior we have undertaken a study to examine the effect of 3 different forms of SAMe. Guide cannulae were sterotaxically implanted into the lateral ventricle of male SD rats (n = 5 for each group) using either ketamine or chloral hydrate anesthesia. 48 h post surgery the rats received a 5‐μL injection containing 1 μmol of either SAMe‐toluenedisulfonate, SAMe‐butanedisulfonate, SAMe‐chloride, or vehicle (butanedisulfonate, toluenedisulfonate or saline). Locomotor activity was monitored using the TruScan monitoring system and by videotape recording for 1 h. The videotape was reviewed by one of the authors (RD‐A) who is experienced with animal models of epilepsy. SAMe injected animals had frequent myoclonic and tonic seizures, and occasional generalized clonic seizures. SAMe induced behavioral seizures and tremors occurred only in rats that had previously been anesthetized with chloral hydrate, and not in rats that received ketamine. The number of movements recorded during the 1‐h period were significantly increased in SAMe injected animals compared to control groups in both chloral hydrate and ketamine anethetized rats. Our studies indicate that there is an anesthetic dependency for SAMe induced seizures and tremors.     

Stability of transgene integration and expression in subsequent generations of doubled haploid oilseed rape transformed with chitinase and β-1,3-glucanase genes in a double-gene construct

A double-gene construct with one chitinase and one β-1,3-glucanase gene from barley, both driven by enhanced 35S promoters, was transformed into oilseed rape. From six primary transformants expressing both transgenes 10 doubled haploid lines were produced and studied for five generations. The number of inserted copies for both the genes was determined by Southern blotting and real-time PCR with full agreement between the two methods. When copy numbers were analysed in different generations, discrepancies were found, indicating that at least part of the inserted sequences were lost in one of the alleles of some doubled haploids. Chitinase and β-1,3-glucanase expression was analysed by Western blotting in all five doubled haploid generations. Despite that both the genes were present on the same T-DNA and directed by the same promoter their expression pattern between generations was different. The β-1,3-glucanase was expressed at high and stable levels in all generations, while the chitinase displayed lower expression that varied between generations. The transgenic plants did not show any major impact on fungal resistance when assayed in greenhouse, although purified β-1,3-glucanase and chitinase caused retardment of fungal growth in vitro.     

Comparison of bone and renal effects in HIV-infected adults switching to abacavir or tenofovir based therapy in a randomized trial

Introduction

Our objective was to compare the bone and renal effects among HIV-infected patients randomized to abacavir or tenofovir-based combination anti-retroviral therapy.

Methods

In an open-label randomized trial, HIV-infected patients were randomized to switch from zidovudine/lamivudine (AZT/3TC) to abacavir/lamivudine (ABC/3TC) or tenofovir/emtricitabine (TDF/FTC). We measured bone mass density (BMD) and bone turnover biomarkers (osteocalcin, osteocalcin, procollagen type 1 N-terminal propeptide (P1NP), alkaline phosphatase, type I collagen cross-linked C-telopeptide (CTx), and osteoprotegerin). We assessed renal function by estimated creatinine clearance, plasma cystatin C, and urinary levels of creatinine, albumin, cystatin C, and neutrophil gelatinase-associated lipocalin (NGAL). The changes from baseline in BMD and renal and bone biomarkers were compared across study arms.

Results

Of 40 included patients, 35 completed 48 weeks of randomized therapy and follow up. BMD was measured in 33, 26, and 27 patients at baseline, week 24, and week 48, respectively. In TDF/FTC-treated patients we observed significant reductions from baseline in hip and lumbar spine BMD at week 24 (−1.8% and −2.5%) and week 48 (−2.1% and −2.1%), whereas BMD was stable in patients in the ABC/3TC arm. The changes from baseline in BMD were significantly different between study arms. All bone turnover biomarkers except osteoprotegerin increased in the TDF/FTC arm compared with the ABC/3TC arm, but early changes did not predict subsequent loss of BMD. Renal function parameters were similar between study arms although a small increase in NGAL was detected among TDF-treated patients.

Conclusion

Switching to TDF/FTC-based therapy led to decreases in BMD and increases in bone turnover markers compared with ABC/3TC-based treatment. No major difference in renal function was observed.

Trial registration

Clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00647244","term_id":"NCT00647244"}}NCT00647244     

Time Delay and Partial Coherence Analyses to Identify Cortical Connectivities

Recently it has been demonstrated by Albo that partial coherence analysis is sensitive to signal to noise ratio (SNR) and that it will always identify the signal with the highest SNR among the three signals as the main (driving) influence. We propose to use time delay analysis in parallel to partial coherence analysis to identify the connectivities between the multivariate time series. Both are applied to a theoretical model (used by Albo) to analyse the connections introduced in the model. Time delay analysis identifies the connections correctly. We also apply these analyses to the electroencephalogram (EEG) and electromyogram of essential tremor patients and EEG of normal subjects while bimanually tapping their index fingers. Biologically plausible cortico-muscular and cortico-cortical connections are identified by these methods.     

Diabetes-related defects in sarcoplasmic Ca2+ release are prevented by inactivation of Gα11 and Gαq in murine cardiomyocytes

Neurohumoral stimulation of Gq-coupled receptors has been proposed as a central mechanism in the pathogenesis of diabetic heart disease. The resulting contractile dysfunction is closely related to abnormal intracellular Ca²⁺ handling with functional defects of the sarcoplasmic reticulum (SR). The present study was therefore designed to determine the role of G_q-protein signaling via Gα₁₁ and Gα_q in diabetes for the induction of functional and structural changes in the Ca²⁺ release complex of the SR. An experimental type 1-diabetes was induced in wild type, Gα₁₁ knockout, and Gα_11/q-knockout mice by injection of streptozotocin. Cardiac morphology and function was assessed in vivo by echocardiography. SR Ca²⁺ leak was tested in vitro based on a ⁴⁵Ca²⁺ assay and protein densities as well as gene expression of ryanodine receptor (RyR2), FKBP12.6, sorcin, and annexin A7 were analyzed by immunoblot and RT-PCR. In wild type animals 8 weeks of diabetes resulted in cardiac hypertrophy and SR Ca²⁺ leak was increased. In addition, diabetic wild type animals showed reduced protein levels of FKBP12.6 and annexin A7. In Gα₁₁- and Gα_11/q-knockout animals, however, SR Ca²⁺ release and cardiac phenotype remained unchanged upon induction of diabetes. Densities of the proteins that we presently analyzed were also unaltered in Gα₁₁-knockout mice. Gα_11/q-knockout animals even showed increased expression of sorcin and annexin A7. Thus, based on the present study we suggest a signaling pathway via the G_q-proteins, Gα₁₁ and Gα_q, that could link increased neurohumoral stimulation in diabetes with defective RyR2 channel function by regulating protein expression of FKBP12.6, annexin A7, and sorcin.     

New genomic region for Wegener’s granulomatosis as revealed by an extended association screen with 202 apoptosis-related genes

Wegeners granulomatosis (WG) is a systemic disease with complex genetic background. It is characterized by necrotizing granulomatous inflammation of the upper and lower respiratory tract, glomerulonephritis, vasculitis and the presence of antineutrophil cytoplasmatic autoantibodies (C-ANCAs) in sera of patients. Here, we report on an extended association screen (EAS) with 202 microsatellite markers, representing apoptosis-related genes and further genes down-regulated in apoptotic neutrophils, using pooled DNA of 150 Northern German patients suffering from WG and 100 healthy Northern German controls. Six microsatellite allele patterns were found significantly associated with WG, three of which could be confirmed by individual genotyping. One marker remained significantly associated after multiple corrections. This marker representing the retinoid X receptor ß gene (RXRB, P=7.60×10^–6, distance to gene: ~5.3 kb) is localised in the major histocompatibility complex (MHC) region between the HLA-DPB1 and DAXX genes. HLA-DPB1 typing and fine mapping of the region with additional microsatellites and single-nucleotide polymorphisms (SNPs) revealed a strong association of WG with the significantly over-represented DPB1*0401 (P=1.51×10^–10, OR=3.91) allele compared with the control cohort. In addition, an extended haplotype DPB1*0401/RXRB03 was identified showing an even stronger association with WG (P=7.13×10^–17, OR=6.41). These results represent the strongest association of a genomic region with WG, suggesting a major genetic contribution in the aetiology of the disease. Thus, our data demonstrate that EAS may be a valuable alternative approach for determining genetic predisposition factors in multifactorial diseases.P. Jagiello and M. Gencik contributed equally to this work     

PCSK6 VNTR Polymorphism Is Associated with Degree of Handedness but Not Direction of Handedness

Although the left and right human cerebral hemispheres differ both functionally and anatomically, the mechanisms that underlie the establishment of these hemispheric specializations, as well as their physiological and behavioral implications, remain largely unknown. Since cerebral asymmetry is strongly correlated with handedness, and handedness is assumed to be influenced by a number of genetic and environmental factors, we performed an association study of LRRTM1 rs6733871 and a number of polymorphisms in PCSK6 and different aspects of handedness assessed with the Edinburgh handedness inventory in a sample of unrelated healthy adults (n = 1113). An intronic 33bp variable-number tandem repeat (VNTR) polymorphism in PCSK6 (rs10523972) shows a significant association (significance threshold: p<0.0025, adjusted for multiple comparisons) with a handedness category comparison (P = 0.0005) and degree of handedness (P = 0.001). These results provide further evidence for the role of PCSK6 as candidate for involvement in the biological mechanisms that underlie the establishment of normal brain lateralization and thus handedness and support the assumption that the degree of handedness, instead the direction, may be the more appropriate indicator of cerebral organization.     

Genome differentiation in Magonoliaceae as revealed from meiotic pairing in interspecific and intergeneric hybrids

The cross compatibility within and between Yulania Spach and Michelia L.(Magnoliaceae) is relatively good and various such hybrids,obtained by conventional artificial hybridization,are available.The aim of the present study was to determine the extent of genome differentiation between the species involved in these crosses through the observation of chromosome pairing during meiosis in pollen mother cells (PMCs) of the hybrids.Chromosome pairing behavior was studied in five species (2n =38) and two interspecific hybrids of Michelia,eight species (2n =38,76 and 114) and 10 interspecific hybrids of Yulania,and three intergeneric hybrids between Michelia and Yulania.The results showed that chromosome pairing was normal with bivalent formation in diploid parental species and in interspecific hybrids.In addition to bivalents,multivalents were encountered in polyploid parental species and polyploid interspecific hybrids.In the intergeneric hybrids between a tetraploid Yulania and two diploid Michelia,19 chromosomes,most likely originating from Michelia,were unable to synapse from zygotene to metaphase I.Meiotic chromosome pairing indicated a high degree of homology between species within Michelia and Yulania and less homology between the genomes of these two genera.The differentiation of morphological characters and the distinctness of natural distribution also support the conclusion that these two genera are likely independent monophyletic groups.This suggests that the two genera were split at early evolution of Magnoliaceae and the overlapping characteristics in external morphology and internal structures of the two genera may be the result of parallel evolution or ancient common ancestry.     

A review of the biology and ecology of the Robber Crab, Birgus latro (Linnaeus, 1767) (Anomura: Coenobitidae)

Birgus latro (L.) is the largest terrestrial hermit crab in the world. The species is widely distributed on remote Indo-Pacific islands of the tropics, but it is rapidly declining and is currently classified as data deficient on the IUCN red list. This review provides a synopsis of both published and unpublished data on the biology and ecology of B. latro. It highlights the lack of robust biological information on the species’ basic biology, particularly in the juvenile and reproductive phases, while behavioural ecology studies are few and report conflicting data between populations. Population studies indicate that B. latro may have limited recruitment events throughout its range, emphasising the need for more systematic research to clearly identify factors that influence successful recruitment events. The review highlights the paucity of substantiated peer reviewed studies on this species and emphasises the need for further systematic research.