Chronic endoplasmic reticulum stress in myotonic dystrophy type 2 promotes autoimmunity via mitochondrial DNA release

Myotonic dystrophy type 2 (DM2) is a tetranucleotide CCTG repeat expansion disease associated with an increased prevalence of autoimmunity. Here, we identified an elevated type I interferon (IFN) signature in peripheral blood mononuclear cells and primary fibroblasts of DM2 patients as a trigger of chronic immune stimulation. Although RNA-repeat accumulation was prevalent in the cytosol of DM2-patient fibroblasts, type-I IFN release did not depend on innate RNA immune sensors but rather the DNA sensor cGAS and the prevalence of mitochondrial DNA (mtDNA) in the cytoplasm. Sublethal mtDNA release was promoted by a chronic activation of the ATF6 branch of the unfolded protein response (UPR) in reaction to RNA-repeat accumulation and non-AUG translated tetrapeptide expansion proteins. ATF6-dependent mtDNA release and resulting cGAS/STING activation could also be recapitulated in human THP-1 monocytes exposed to chronic endoplasmic reticulum (ER) stress. Altogether, our study demonstrates a novel mechanism by which large repeat expansions cause chronic endoplasmic reticulum stress and associated mtDNA leakage. This mtDNA is, in turn, sensed by the cGAS/STING pathway and induces a type-I IFN response predisposing to autoimmunity. Elucidating this pathway reveals new potential therapeutic targets for autoimmune disorders associated with repeat expansion diseases.

A Sequential Targeting Strategy Interrupts AKT-Driven Subclone-Mediated Progression in Glioblastoma

PURPOSE

Therapy resistance and fatal disease progression in glioblastoma are thought to result from the dynamics of intra-tumor heterogeneity. This study aimed at identifying and molecularly targeting tumor cells that can survive, adapt, and subclonally expand under primary therapy.

EXPERIMENTAL DESIGN

To identify candidate markers and to experimentally access dynamics of subclonal progression in glioblastoma, we established a discovery cohort of paired vital cell samples obtained before and after primary therapy. We further used two independent validation cohorts of paired clinical tissues to test our findings. Follow-up preclinical treatment strategies were evaluated in patient-derived xenografts.

RESULTS

We describe, in clinical samples, an archetype of rare ALDH1A1+ tumor cells that enrich and acquire AKT-mediated drug resistance in response to standard-of-care temozolomide (TMZ). Importantly, we observe that drug resistance of ALDH1A1+ cells is not intrinsic, but rather an adaptive mechanism emerging exclusively after TMZ treatment. In patient cells and xenograft models of disease, we recapitulate the enrichment of ALDH1A1+ cells under the influence of TMZ. We demonstrate that their subclonal progression is AKT-driven and can be interfered with by well-timed sequential rather than simultaneous antitumor combination strategy.

CONCLUSIONS

Drug-resistant ALDH1A1+/pAKT+ subclones accumulate in patient tissues upon adaptation to TMZ therapy. These subclones may therefore represent a dynamic target in glioblastoma. Our study proposes the combination of TMZ and AKT inhibitors in a sequential treatment schedule as a rationale for future clinical investigation.

Rapid testing of candidate oncogenes and tumour suppressor genes in signal transduction and neoplastic transformation

The COSMIC database (version 94) lists 576 genes in the Cancer Gene Census which have a defined function as drivers of malignancy (oncogenes) or as tumour suppressors (Tier 1). In addition, there are 147 genes with similar functions, but which are less well characterised (Tier 2). Furthermore, next-generation sequencing projects in the context of precision oncology activities are constantly discovering new ones. Since cancer genes differ from their wild-type precursors in numerous molecular and biochemical properties and exert significant differential effects on downstream processes, simple assays that can uncover oncogenic or anti-oncogenic functionality are desirable and may precede more sophisticated analyses. We describe simple functional assays for PTPN11 (protein-tyrosine phosphatase, non-receptor-type 11)/SHP2 mutants, which are typically found in RASopathies and exhibit potential oncogenic activity. We have also designed a functional test for lysyl oxidase (LOX), a prototypical class II tumour suppressor gene whose loss of function may contribute to neoplastic transformation by RAS oncogenes. Moreover, we applied this test to analyse three co-regulated, RAS-responsive genes for transformation-suppressive activity. The integration of these tests into systems biology studies will contribute to a better understanding of cellular networks in cancer.

Functional Subclone Profiling for Prediction of Treatment-Induced Intratumor Population Shifts and Discovery of Rational Drug Combinations in Human Glioblastoma

PURPOSE

Investigation of clonal heterogeneity may be key to understanding mechanisms of therapeutic failure in human cancer. However, little is known on the consequences of therapeutic intervention on the clonal composition of solid tumors.

EXPERIMENTAL DESIGN

Here, we used 33 single cell-derived subclones generated from five clinical glioblastoma specimens for exploring intra- and interindividual spectra of drug resistance profiles in vitro In a personalized setting, we explored whether differences in pharmacologic sensitivity among subclones could be employed to predict drug-dependent changes to the clonal composition of tumors.

RESULTS

Subclones from individual tumors exhibited a remarkable heterogeneity of drug resistance to a library of potential antiglioblastoma compounds. A more comprehensive intratumoral analysis revealed that stable genetic and phenotypic characteristics of coexisting subclones could be correlated with distinct drug sensitivity profiles. The data obtained from differential drug response analysis could be employed to predict clonal population shifts within the naïve parental tumor in vitro and in orthotopic xenografts. Furthermore, the value of pharmacologic profiles could be shown for establishing rational strategies for individualized secondary lines of treatment.

CONCLUSIONS

Our data provide a previously unrecognized strategy for revealing functional consequences of intratumor heterogeneity by enabling predictive modeling of treatment-related subclone dynamics in human glioblastoma. Clin Cancer Res; 23(2); 562-74. ©2016 AACR.

Phase I trial of dovitinib (TKI258) in recurrent glioblastoma

PURPOSE

Dovitinib (TKI258) is an oral multi-tyrosine kinase inhibitor of FGFR, VEGFR, PDGFR β, and c-Kit. Since dovitinib is able to cross the blood-brain barrier and targets brain tumor-relevant pathways, we conducted a phase I trial to demonstrate its safety in recurrent glioblastoma (GBM).

PATIENTS AND METHODS

Patients with first or second GBM recurrence started treatment with the maximal tolerated dose (MTD) previously established in systemic cancer patients (500 mg/d, 5 days on/2 days off). A modified 3 + 3 design in three cohorts (500, 400, 300 mg) was used.

RESULTS

Twelve patients were enrolled. Seventy-two adverse events (AEs) occurred and 16.7 % of AEs were classified as ≥CTC grade 3 toxicity, mainly including hepatotoxicity and hematotoxicity. Only one out of six patients of the 300-mg cohort showed grade 3 toxicity. The PFS-6 rate was 16.7 %, and it was not associated with detection of the FGFR-TACC gene fusion in the tumor.

CONCLUSION

Dovitinib is safe in patients with recurrent GBM and showed efficacy in only some patients unselected for target expression. The recommended phase II dose of 300 mg would be substantially lower than the recently established MTD in systemic cancer patients. Further personalized trials are recommended.

Systematic review: microbial dysbiosis and nonalcoholic fatty liver disease

BACKGROUND

The human intestinal microbiota is a key regulator of host metabolic and immune functions and alterations in the microbiome ('dysbiosis') have been implicated in several human diseases. Because of the anatomical links between the intestines and the liver, dysbiosis may also disrupt hepatic function and thereby contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD).

AIM

To perform a comprehensive review of the medical literature investigating associations between intestinal dysbiosis and NAFLD, with a particular emphasis on studies that characterise the microbiome in NAFLD.

METHODS

We conducted a search of PubMed, Embase, and Web of Science using multiple search terms including: 'NAFLD, NASH, fatty liver, steatohepatitis' combined with 'metagenome, microbiom*, microbiota*, fecal flora, intestinal flora, gut bacteria'. Results were manually reviewed and studies selected based on relevance to intestinal microbiota and NAFLD. We also included studies that addressed potential mechanistic models of pathways linking the dysbiosis to NAFLD.

RESULTS

Nine studies (five human and four animal models) were identified in our search that assessed associations between specific intestinal microbiota composition and NAFLD. We reviewed and summarised the results of additional investigations that more broadly addressed the mechanisms by which the microbiome may impact NAFLD pathogenesis.

CONCLUSIONS

Investigations in humans and animals demonstrate associations between intestinal dysbiosis and NAFLD; however, causality has not been proven and mechanistic links require further delineation. As the field of microbiome research matures in techniques and study design, more detailed insights into NAFLD pathogenesis and its associations with the intestinal microbiota will be elucidated.

Anticancer effects of niclosamide in human glioblastoma

PURPOSE

Glioblastoma is a highly malignant, invariably fatal brain tumor for which effective pharmacotherapy remains an unmet medical need.

EXPERIMENTAL DESIGN

Screening of a compound library of 160 synthetic and natural toxic substances identified the antihelmintic niclosamide as a previously unrecognized candidate for clinical development. Considering the cellular and interindividual heterogeneity of glioblastoma, a portfolio of short-term expanded primary human glioblastoma cells (pGBM; n = 21), common glioma lines (n = 5), and noncancer human control cells (n = 3) was applied as a discovery platform and for preclinical validation. Pharmacodynamic analysis, study of cell-cycle progression, apoptosis, cell migration, proliferation, and on the frequency of multipotent/self-renewing pGBM cells were conducted in vitro, and orthotopic xenotransplantation was used to confirm anticancer effects in vivo.

RESULTS

Niclosamide led to cytostatic, cytotoxic, and antimigratory effects, strongly reduced the frequencies of multipotent/self-renewing cells in vitro, and after exposure significantly diminished the pGBMs' malignant potential in vivo. Mechanism of action analysis revealed that niclosamide simultaneously inhibited intracellular WNT/CTNNB1-, NOTCH-, mTOR-, and NF-κB signaling cascades. Furthermore, combinatorial drug testing established that a heterozygous deletion of the NFKBIA locus in glioblastoma samples could serve as a genomic biomarker for predicting a synergistic activity of niclosamide with temozolomide, the current standard in glioblastoma therapy.

CONCLUSIONS

Together, our data advocate the use of pGBMs for exploration of compound libraries to reveal unexpected leads, for example, niclosamide that might be suited for further development toward personalized clinical application.

Targeting the cytosolic innate immune receptors RIG-I and MDA5 effectively counteracts cancer cell heterogeneity in glioblastoma

Cellular heterogeneity, for example, the intratumoral coexistence of cancer cells with and without stem cell characteristics, represents a potential root of therapeutic resistance and a significant challenge for modern drug development in glioblastoma (GBM). We propose here that activation of the innate immune system by stimulation of innate immune receptors involved in antiviral and antitumor responses can similarly target different malignant populations of glioma cells. We used short-term expanded patient-specific primary human GBM cells to study the stimulation of the cytosolic nucleic acid receptors melanoma differentiation-associated gene 5 (MDA5) and retinoic acid-inducible gene I (RIG-I). Specifically, we analyzed cells from the tumor core versus "residual GBM cells" derived from the tumor resection margin as well as stem cell-enriched primary cultures versus specimens without stem cell properties. A portfolio of human, nontumor neural cells was used as a control for these studies. The expression of RIG-I and MDA5 could be induced in all of these cells. Receptor stimulation with their respective ligands, p(I:C) and 3pRNA, led to in vitro evidence for an effective activation of the innate immune system. Most intriguingly, all investigated cancer cell populations additionally responded with a pronounced induction of apoptotic signaling cascades revealing a second, direct mechanism of antitumor activity. By contrast, p(I:C) and 3pRNA induced only little toxicity in human nonmalignant neural cells. Granted that the challenge of effective central nervous system (CNS) delivery can be overcome, targeting of RIG-I and MDA5 could thus become a quintessential strategy to encounter heterogeneous cancers in the sophisticated environments of the brain.

PAX2 regulates ADAM10 expression and mediates anchorage-independent cell growth of melanoma cells

PAX transcription factors play an important role during development and carcinogenesis. In this study, we investigated PAX2 protein levels in melanocytes and melanoma cells by Western Blot and immunofluorescence analysis and characterized the role of PAX2 in the pathogenesis of melanoma. In vitro we found weak PAX2 protein expression in keratinocytes and melanocytes. Compared to melanocytes increased PAX2 protein levels were detectable in melanoma cell lines. Interestingly, in tissue sections of melanoma patients nuclear PAX2 expression strongly correlated with nuclear atypia and the degree of prominent nucleoli, indicating an association of PAX2 with a more atypical cellular phenotype. In addition, with chromatin immunoprecipitation assay, PAX2 overexpression and PAX2 siRNA we present compelling evidence that PAX2 can regulate ADAM10 expression, a metalloproteinase known to play important roles in melanoma metastasis. In human tissue samples we found co-expression of PAX2 and ADAM10 in melanocytes of benign nevi and in melanoma cells of patients with malignant melanoma. Importantly, the downregulation of PAX2 by specific siRNA inhibited the anchorage independent cell growth and decreased the migratory and invasive capacity of melanoma cells. Furthermore, the downregulation of PAX2 abrogated the chemoresistance of melanoma cells against cisplatin, indicating that PAX2 expression mediates cell survival and plays important roles during melanoma progression.

L1-CAM expression in ccRCC correlates with shorter patients survival times and confers chemoresistance in renal cell carcinoma cells

Conflicting data exist about the expression of L1 cell adhesion molecule (L1-CAM) in clear cell renal cell carcinoma (ccRCC). To determine the clinical usefulness of L1-CAM as a therapeutic or prognostic marker molecule in renal cancer patients, we analyzed its expression on a cohort of 282 renal cell carcinoma (RCC) patients. L1-CAM expression was found in 49.5% of 282 renal cancer tissues. Importantly, L1-CAM expression in patients with ccRCC was associated with significantly shorter patient survival time. We further present evidence that L1-CAM was involved in the resistance against therapeutic reagents like rapamycin, sunitinib and cisplatin. The downregulation of L1-CAM expression decreased renal cancer cell proliferation and reduced the expression of cyclin D1. In addition, we found out that Von Hippel-Lindau (VHL) deficiency was accompanied by a downregulation of the transcription factor PAX8 and L1-CAM. In normal renal tissue, PAX8 and L1-CAM were co-expressed in collecting duct cells. Importantly, the downregulation of PAX8 by small interfering RNA increased the expression of L1-CAM and concomitantly induced the migration of renal cancer cells. Furthermore, we observed in 65.3% of 282 RCC patients a downregulation of PAX8 expression. With chromatin immunoprecipitation analysis, we additionally demonstrate that PAX8 can bind to the promoter of L1-CAM and we further observed that the downregulation of PAX8 was accompanied by increased L1-CAM expression in a high fraction of ccRCC patients. In summary, we show that VHL and PAX8 are involved in the regulation of L1-CAM in renal cancer and L1-CAM represents an important therapeutic and prognostic marker protein for the treatment of ccRCC.

The potential for hydrocarbon biodegradation and production of extracellular polymeric substances by aerobic bacteria isolated from a Brazilian petroleum reservoir

Extracellular polymeric substances (EPS) can contribute to the cellular degradation of hydrocarbons and have a huge potential for application in biotechnological processes, such as bioremediation and microbial enhanced oil recovery (MEOR). Four bacterial strains from a Brazilian petroleum reservoir were investigated for EPS production, emulsification ability and biodegradation activity when hydrocarbons were supplied as substrates for microbial growth. Two strains of Bacillus species had the highest EPS production when phenanthrene and n-octadecane were offered as carbon sources, either individually or in a mixture. While Pseudomonas sp. and Dietzia sp., the other two evaluated strains, had the highest hydrocarbon biodegradation indices, EPS production was not detected. Low EPS production may not necessarily be indicative of an absence of emulsifier activity, as indicated by the results of a surface tension reduction assay and emulsification indices for the strain of Dietzia sp. The combined results gathered in this work suggest that a microbial consortium consisting of bacteria with interdependent metabolisms could thrive in petroleum reservoirs, thus overcoming the limitations imposed on each individual species by the harsh conditions found in such environments.

Proposal to elevate Mycobacterium avium complex ITS sequevar MAC-Q to Mycobacterium vulneris sp. nov

The Mycobacterium avium complex (MAC) consists of four recognized species, Mycobacterium avium, Mycobacterium colombiense, Mycobacterium intracellulare and Mycobacterium chimaera, and a variety of other strains that may be members of undescribed taxa. We report on two isolates of a scotochromogenic, slowly growing, non-tuberculous Mycobacterium species within the M. avium complex from a lymph node and an infected wound after a dogbite of separate patients in The Netherlands. The extrapulmonary infections in immunocompetent patients suggested a high level of virulence. These isolates were characterized by a unique nucleotide sequence in the 16S rRNA gene, 99% similar to Mycobacterium colombiense, and the MAC-Q 16S-23S internal transcribed spacer (ITS) sequence. Sequence analyses of the hsp65 gene revealed 97% similarity to M. avium. The rpoB gene sequence was 98% similar to M. colombiense. Phenotypically, the scotochromogenicity, positive semi-quantitative catalase and heat-stable catalase tests, negative tellurite reductase and urease tests and susceptibility to hydroxylamine and oleic acid set these isolates apart from related species. High-performance liquid chromatography analysis of cell-wall mycolic acid content revealed a unique pattern, related to that of M. avium and M. colombiense. Together, these findings supported a separate species status within the Mycobacterium avium complex. We propose elevation of scotochromogenic M. avium complex strains sharing this 16S gene and MAC-Q ITS sequence to separate species status, for which the name Mycobacterium vulneris sp. nov. is proposed. The type strain is NLA000700772T (=DSM 45247T=CIP 109859T).

Carbon pools and isotopic trends in a hypersaline cyanobacterial mat

The fine-scale depth distribution of major carbon pools and their stable carbon isotopic signatures (delta(13)C) were determined in a cyanobacterial mat (Salin-de-Giraud, Camargue, France) to study early diagenetic alterations and the carbon preservation potential in hypersaline mat ecosystems. Particular emphasis was placed on the geochemical role of extracellular polymeric substances (EPS). Total carbon (C(tot)), organic carbon (C(org)), total nitrogen (N(tot)), total hydrolysable amino acids (THAA), carbohydrates, cyanobacteria-derived hydrocarbons (8-methylhexadecane, n-heptadec-5-ene, n-heptadecane) and EPS showed highest concentrations in the top millimetre of the mat and decreased with depth. The hydrocarbons attributed to cyanobacteria showed the strongest decrease in concentration with depth. This correlated well with the depth profiles of oxygenic photosynthesis and oxygen, which were detected in the top 0.6 and 1.05 mm, respectively, at a high down-welling irradiance (1441 micromol photons m(-2) s(-1)). At depths beneath the surface layer, the C(org) was composed mainly of amino acids and carbohydrates. A resistance towards microbial degradation could have resulted from interactions with diverse functional groups present in biopolymers (EPS) and with minerals deposited in the mat. A (13)C enrichment with depth for the total carbon pool (C(tot)) was observed, with delta(13)C values ranging from -16.3 per thousand at the surface to -11.3 per thousand at 9-10 mm depth. Total lipids depicted a delta(13)C value of -17.2 per thousand in the top millimetre and then became depleted in (13)C with depth (-21.7 to -23.3 per thousand). The delta(13)C value of EPS varied only slightly with depth (-16.1 to -17.3 per thousand) and closely followed the delta(13)C value of C(org) at depths beneath 4 mm. The EPS represents an organic carbon pool of preservation potential during early stages of diagenesis in recent cyanobacterial mats as a result of a variety of possible interactions. Their analyses might improve our understanding of fossilized microbial remains from mat ecosystems.

An overview of the integration of ozone systems in biological treatment steps

Despite the well-known potential and performance of combined biological and ozonation processes for wastewater treatment, only few full-scale applications are published. Beside the synergistic effects of such process combination, which lead to oxidation of recalcitrant and inhibitory compounds or intermediates by enhancement of their biodegradability, the key for raising applicability is the improvement of the ozonation efficiency. An overview about the history and progress of full-scale applications, which deals with combined ozonation and biological treatment is given. Recently more than 40 applications exist, but many of them are not published. Therefore, a couple of selected not yet published applications have been mentioned in this paper. Landfill leachate and industrial wastewater treatment were mostly applicated, while treatment of municial wastewater treatment plant (WWTP) effluents are of increasing interest due to several advantages such as disinfection, decolourisation and removal of persistent dissolved organic carbon (DOC) for water re-use and groundwater recharge.

Biogeochemistry of an iron-rich hypersaline microbial mat (Camargue, France)

In situ microsensor measurements were combined with biogeochemical methods to determine oxygen, sulfur, and carbon cycling in microbial mats growing in a solar saltern (Salin-de-Giraud, France). Sulfate reduction rates closely followed the daily temperature changes and were highest during the day at 25 degrees C and lowest during the night at 11 degrees C, most probably fueled by direct substrate interactions between cyanobacteria and sulfate-reducing bacteria. Sulfate reduction was the major mineralization process during the night and the contribution of aerobic respiration to nighttime DIC production decreased. This decrease of aerobic respiration led to an increasing contribution of sulfide (and iron) oxidation to nighttime O2 consumption. A peak of elemental sulfur in a layer of high sulfate reduction at low sulfide concentration underneath the oxic zone indicated anoxygenic photosynthesis and/or sulfide oxidation by iron, which strongly contributed to sulfide consumption. We found a significant internal carbon cycling in the mat, and sulfate reduction directly supplied DIC for photosynthesis. The mats were characterized by a high iron content of 56 micromol Fe cm(-3), and iron cycling strongly controlled the sulfur cycle in the mat. This included sulfide precipitation resulting in high FeS contents with depth, and reactions of iron oxides with sulfide, especially after sunset, leading to a pronounced gap between oxygen and sulfide gradients and an unusual persistence of a pH peak in the uppermost mat layer until midnight.

Microbial mats on the Orkney Islands revisited: microenvironment and microbial community composition

The microenvironment and community composition of microbial mats developing on beaches in Scapa Flow (Orkney Islands) were investigated. Analysis of characteristic biomarkers (major fatty acids, hydrocarbons, alcohols, and alkenones) revealed the presence of different groups of bacteria and microalgae in mats from Waulkmill and Swanbister beach, including diatoms, Haptophyceae, cyanobacteria, and sulfate-reducing bacteria. These analyses also indicated the presence of methanogens, especially in Swanbister beach mats, and therefore a possible role of methanogenesis for the carbon cycle of these sediments. High amounts of algal lipids and slightly higher numbers (genera, abundances) of cyanobacteria were found in Waulkmill Bay mats. However, overall only a few genera and low numbers of unicellular and filamentous cyanobacteria were present in mats from Waulkmill and Swanbister beach, as deduced from CLSM (confocal laser scanning microscopy) analysis. Spectral scalar irradiance measurements with fiber-optic microprobes indicated a pronounced heterogeneity concerning zonation and density of mainly anoxygenic phototrophs in Swanbister Bay mats. By microsensor and T-RFLP (terminal restriction fragment length polymorphism) analysis in Swanbister beach mats, the depth distribution of different populations of purple and sulfate-reducing bacteria could be related to the microenvironmental conditions. Oxygen, but also sulfide and other (inorganic and organic) sulfur compounds, seems to play an important role in the stratification and diversity of these two major bacterial groups involved in sulfur cycling in Swanbister beach mats.

Analysis of the gene structure of the human (SLC22A3) and murine (Slc22a3) extraneuronal monoamine transporter

The organic cation transporter 3 (OCT3), also termed as extraneuronal monoamine transporter (EMT), is known to be expressed in glial cells where it is responsible for the uptake of catecholamines and neurotoxic organic cations such as 1-methyl-4-phenylpyridinium (MPP+). We have now analyzed the structure of the human and murine OCT3 gene. The coding regions of both genes consist of 11 exons and 10 introns. All exon-intron junctions contain fully conserved gt/ag consensus splice sites. The human introns are without exception larger than their murine counterparts. In both genes, the introns, apart from intron 1, are located at the same position. Mouse and human exons have the same size with exception of exon 1 which is 15 bp larger in the human gene. The organization of the human OCT3 gene also shows pronounced similarities with other genes of human organic cation transporters such as those for hOCT1, hOCTN2, hORCTL3, and hORCTL4. The genes of these transporters share about the same exon-intron structure and exon sizes, indicating that the genes may have evolved from a common anchestor gene through duplication. Knowledge of the human gene structure of the OCT3 should enable investigations of possible polymorphisms and their involvement in e.g. psychiatric disorders; and knowledge of the mouse exon-intron organization is essential for generating a knock-out mouse which should help to recognize the physiological importance of the OCT3.

Molecular cloning and functional expression of the mouse dopamine transporter

The full coding region of the murine dopamine transporter (mDAT) cDNA was cloned by PCR with a sense primer derived from the partial mDAT gene sequence and an antisense primer deduced from the rat dopamine transporter cDNA. The mDAT cDNA encodes a typical member of the family of Na+- and Cl--dependent neurotransmitter transporters with 99.2; 93.4 and 85.4% amino acid identity to the rat, human and bovine DATs, respectively. Functional expression of the mDAT cDNA in transiently transfected human embryonic kidney (HEK293) cells exhibited the typical pharmacological features of a dopamine transporter. [3H]dopamine uptake through the mDAT was inhibited with high potency by GBR12909 (IC50 = 5.2 nM) and not significantly affected by 100 nM desipramine. [3H]dopamine uptake also was inhibited through increasing concentrations of dopamine (IC50 = 0.93 microM) or 1-methyl-4-phenylpyridinium (MPP+; IC50 = 13.2microM).

Epicuticular waxes and flavonol aglycones of the European mistletoe, Viscum album L

Cuticular waxes of Viscum album ssp. album contain oleanolic acid as main constituent, accompanied by aliphatic compounds like alkanes, esters and primary alcohols. A number of flavonol aglycones (methyl ethers of quercetin and kaempferol) have also been identified. Seasonal changes in amount and composition of cuticular waxes and the presence of flavonol aglycones are described and the ecophysiological significance of flavonoids on the surface of the mistletoe is briefly discussed.

Occupational asthma due to unheated colophony

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