Mecardonia tenella (Plantaginaceae) Attracts Oil-, Perfume-, and Pollen-Gathering Bees in Southern Brazil

Floral characteristics often indicate the pollinators' functional group visiting the plant and the pollination syndromes associated with them. This idea has been challenged in the past decades due to increasing evidence that most plants, including those exhibiting floral syndromes, are visited by large arrays of species that differ in their effectiveness as pollinators. Our study focuses on Mecardonia tenella (Plantaginaceae) from the Araucaria forest of southern Brazil, which exhibits characteristics of the oil flower pollination syndrome. However, it is visited by three types of functional groups of bees: male orchid bees, oil-collecting bees, and pollen-seeking bees. The relative contribution of each functional group to the plant's reproductive success was estimated based on their pollen load, visitation frequency, and morphology. We assessed resources, phenology, and breeding system of M. tenella . Our results indicate that flowers lack nectar, but volatiles, lipids, and pollen are resources that can be gathered by visitors. This combination of floral traits and visitors' assemblage makes M. tenella a challenge to the concept of pollination syndromes. Our findings indicate that the current interactions may not reflect the circumstances under which some floral traits of this plant were selected.     

Uptake of [(3)H]glycine by synaptosomes of channel

It is known that channel catfish erythrocytes can take up glycine by several distinct transport systems. Further, glycine is an inhibitory neurotransmitter in mammalian brain and spinal cord. Consequently, the uptake of [(3)H]glycine by catfish brain was investigated and found to be a saturable process, dependent on the presence of Na(++) and Cl(--) and sensitive to temperature. A kinetic analysis of transport was performed at 22C. This showed that a high-affinity system existed which exhibited a K(m) of 5.1 (+/- 2. 1) microM. Several structural analogues of glycine were capable of inhibiting uptake in a competitive manner. The most effective inhibitor was sarcosine (IC(50) 5 36 microM). Uptake was also able to be inhibited by harmaline, a drug known to interfere with Na(+)-dependent transport processes. It is concluded that glycine transport by channel catfish brain has much in common with transport by mammalian nervous tissue which is carried out by the membrane carriers GLYT1 and GLYT2. On the other hand, synaptosomal transport differs somewhat from glycine transport by channel catfish erythrocytes.     

Quantitative polymerase chain reaction as a reliable method to determine functional lentiviral titer after ex vivo gene transfer in human mesenchymal stem cells

BACKGROUND: Human mesenchymal stem cells (hMSCs) are a promising target for ex vivo gene therapy and lentiviruses are excellent gene transfer vehicles in hMSCs since they achieve high transduction rates with long-term gene expression. Nevertheless, senescence of hMSCs may limit therapeutic applications due to time-consuming cell selection and viral titration. Here, we describe a fast and reliable method to determine functional lentiviral titer by quantitative polymerase chain reaction (qPCR) after highly efficient ex vivo gene transfer in hMSCs. METHODS: Lentivirus production was tested with different types of packaging systems. Using p24 ELISA remaining viral particles were detected in the cell culture supernatant. The lentiviral gene transfer efficiency was quantified by FACS analysis. Lentiviral titers were determined by qPCR of expressed transgenes. RESULTS: Third-generation self-inactivating vectors showed highly efficient gene transfer in hMSCs. No viral antigen was detected in the cell culture supernatant after four media changes, suggesting the absence of infectious particles after 4 days. We observed a linear correlation between virus dilution and level of transgene expression by qPCR analysis, therefore allowing viral titering by quantification of transgene expression. Finally, we demonstrated that transduced hMSCs retained their stem cell character by differentiation towards adipogenic, osteogenic and chondrogenic lineages. CONCLUSIONS: Quantification of transgene copy numbers by qPCR is a fast and reliable method to determine functional lentiviral titer after ex vivo gene transfer in hMSCs.     

Unsaturated fatty acid regulation of cytochrome P450 expression via a CAR-dependent pathway

The liver is responsible for key metabolic functions, including control of normal homoeostasis in response to diet and xenobiotic metabolism/detoxification. We have shown previously that inactivation of the hepatic cytochrome P450 system through conditional deletion of POR (P450 oxidoreductase) induces hepatic steatosis, liver growth and P450 expression. We have exploited a new conditional model of POR deletion to investigate the mechanism underlying these changes. We demonstrate that P450 induction, liver growth and hepatic triacylglycerol (triglyceride) homoeostasis are intimately linked and provide evidence that the observed phenotypes result from hepatic accumulation of unsaturated fatty acids, which mediate these phenotypes by activation of the nuclear receptor CAR (constitutive androstane receptor) and, to a lesser degree, PXR (pregnane X receptor). To our knowledge this is the first direct evidence that P450s play a major role in controlling unsaturated fatty acid homoeostasis via CAR. The regulation of P450s involved in xenobiotic metabolism by this mechanism has potentially significant implications for individual responses to drugs and environmental chemicals.     

Determinants of Survival in Malignant Pleural Mesothelioma: A Surveillance,Epidemiology, and End Results (SEER) Study of 14,228 Patients

Introduction

Left untreated, malignant pleural mesothelioma (MPM) is associated with uniformly poor prognosis. Better survival has been reported with surgery-based multimodality therapy, but to date, no trial has demonstrated survival benefit of surgery over other therapies. We evaluated whether cancer-directed surgery influenced survival independently from other predictors in a large population-based dataset.

Methods

The SEER database was explored from 1973 to 2009 to identify all cases of pathologically-proven MPM. Age, sex, race, year of diagnosis, histology stage, cancer-directed surgery, radiation, and vital status were analyzed. The association between prognostic factors and survival was estimated using Cox regression and propensity matched analysis.

Results

There were 14,228 patients with pathologic diagnosis of MPM. On multivariable analysis, female gender, younger age, early stage, and treatment with surgery were independent predictors of longer survival. In comparison to no treatment, surgery alone was associated with significant improvement in survival [adjusted hazard ratio (adj HR) 0.64 (0.61–0.67)], but not radiation [adj HR 1.15 (1.08–1.23)]. Surgery and radiation combined had similar survival as surgery alone [adj HR 0.69 (0.64–0.76)]. Results were similar when cases diagnosed between 1973 and 1999 were compared to cases diagnosed between 2000 and 2009.

Conclusions

Despite developments in surgical and radiation techniques, the prognosis for MPM patients has not improved over the past 4 decades. Cancer-directed surgery is independently associated with better survival, suggesting that multimodal surgery-based therapy can benefit these patients. Further research in adjuvant treatment is necessary to improve prognosis in this challenging disease.     

Isolation and characterisation of nuclear mutants with enhanced mitochondrial mutability in the fission yeast Schizosaccharomyces pombe

In this paper we report the isolation and preliminary characterisation of nuclear mutants with increased mitochondrial mutability in fission yeast. Screening of about 2000 clones after nitrosoguanidine mutagenesis led to the isolation of ten mutator mutants. For one of them (mut-1) we show that the mutation is chromosomally encoded. The activity of the mutator is restricted to the mitochondrial genome, since it increases the mutation rate to mitochondrially encoded drug resistance considerably, whereas the mutability of nuclear genes is not altered.     

Partial hypoxanthine-guanine phosphoribosyl transferase deficiency with full expression of the Lesch-Nyhan syndrome

Summary A patient with the full clinical expression of the classical Lesch-Nyhan syndrome is presented with a residual hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity of 5–10% in erythrocyte lysate and about 30% in fibroblast lysate. The activities of other erythrocyte enzymes of purine metabolism were typical for a classical Lesch-Nyhan patient. The effects of allopurinol therapy on the excretion of urinary purine metabolites were studied by a newly developed isotachophoretic technique.The unusually high residual activity of HGPRT in erythrodytes and fibroblasts of the patient enabled the enzymologic characterization of the mutant enzyme: in fibroblasts the affinities for the substrates hypoxanthine and guanine were normal. However, there was an increased apparent K _m for phosphoribosylpyrophosphate (PRPP), a complete absence of product inhibition by IMP and GMP, and a decreased heat stability. Addition of PRPP did not stabilize the mutant enzyme. In addition to the altered properties of the fibroblast enzyme, the K _m of the erythrocyte enzyme for hypoxanthine was also increased.Immunoprecipitation experiments revealed the presence of an approximately normal amount of material cross-reacting with anti-human HGPRT antiserum. However, it appeared that this cross-reacting material had a decreased stability. When intact erythrocytes were incubated with radiolabeled purine bases, no formation of IMP or GMP could be detected, despite the relatively high residual activity of HGPRT in the hemolysate. The results fit the following hypothesis: as a consequence of a structural mutation affecting the PRPP-site of the enzyme and a decreased heat stability, the activity of the mutant enzyme under in vivo conditions is virtually zero.In the erythrocytes of the patient's mother a normal HGPRT-activity was found. However, the activity in her fibroblasts was lower than normal, while a decreased heat stability and an intermediate behavior towards IMP could be shown.Hair root analysis of several members of the patient's family confirmed the heterozygosity of the mother, whereas no other heterozygotes could be detected. The family anamnesis did not show other cases of Lesch-Nyhan syndrome. These findings were taken as evidence that the patient described in this paper might represent a mutation orginating from the gametes in either of the maternal grandparents.