Regulation of P-Glycoprotein in Renal Proximal Tubule Epithelial Cells by LPS and TNF-α

During endotoxemia, the ATP-dependent drug efflux pump P-glycoprotein (Abcb1/P-gp) is upregulated in kidney proximal tubule epithelial cells. The signaling pathway through which lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α) regulates P-gp expression and activity was investigated further in the present study. Exposure of rat kidney proximal tubule cells to TNF-α alone or TNF-α and LPS increased P-gp gene and protein expression levels and efflux activity, suggesting de novo P-gp synthesis. Upon exposure to TNF-α in combination with LPS, P-gp activity in renal proximal tubule cells is increased under influence of nitric oxide (NO) produced by inducible NO synthase. Upon exposure to TNF-α alone, P-gp upregulation seems to involve TLR4 activation and nuclear factor kappaB (NF-κB) translocation, a pathway that is likely independent of NO. These findings indicate that at least two pathways regulate P-gp expression in the kidney during endotoxemia

HAWAIIAN SKIRT controls size and floral organ number by modulating CUC1 and CUC2 expression

The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT (HWS) affects organ growth and the timing of floral organ abscission. The loss-of-function hws-1 mutant exhibits fused sepals and increased organ size. To understand the molecular mechanisms of HWS during plant development, we mutagenized hws-1 seeds with ethylmethylsulphonate (EMS) and screened for mutations suppressing hws-1 associated phenotypes. We isolated the shs1/hws-1 (suppressor of hws-1) mutant in which hws-1 sepal fusion phenotype was suppressed. The shs1/hws-1 mutant carries a G→A nucleotide substitution in the MIR164 binding site of CUP-SHAPED COTYLEDON 1 (CUC1) mRNA. CUC1 and CUP-SHAPED COTYLEDON 2 (CUC2) transcript levels were altered in shs1, renamed cuc1-1D, and in hws-1 mutant. Genetic interaction analyses using single, double and triple mutants of cuc1-1D, cuc2-1D (a CUC2 mutant similar to cuc1-1D), and hws-1, demonstrate that HWS, CUC1 and CUC2 act together to control floral organ number. Loss of function of HWS is associated with larger petal size due to alterations in cell proliferation and mitotic growth, a role shared with the CUC1 gene

HAWAIIAN SKIRT, and F-box gene from Arabidopsis, is a new player in the microRNA pathway

F-box proteins belong to a multi-protein E3 ubiquitin ligase complex (SCF) that target proteins for degradation via the proteasome.We demonstrated that HAWAIIAN SKIRT(HWS), an Arabidopsis ubiquitin protein ligase (SCFHWS), regulates organ growth, flower development and timing of abscission. Mutants of this gene (hws-1) are pleiotropic and the most obvious phenotype is the fusion of its floral organs, a phenotype shared with the cuc1/cuc2 double mutants and over-expressing lines of MIR164B. To understand the molecular mechanisms of HWS during plant development, an ethylmethylsulphonate mutagenized population of hws-1 seeds was generated and screened for mutations suppressing the hws-1 sepal fusion. We isolated shs-1/hws-1, shs-2/hws-1, and shs-3/hws-1, (suppressor of hws-1) mutants. Mapping analyses shown that shs1 is mutated in the miRNA164 binding site of CUPSHAPED COTYLEDON1 (CUC1) mRNA; while shs-2 and shs-3 are novel alleles of the plant homolog of Exporting-5 HASTY (HST), known to be important in miRNA biogenesis, function and transport. Consequently, we renamed them cuc1-1D, hst23 and hst24, respectively. We demonstrated that transcript levels of CUC1 and CUPSHAPED COTYLEDON 2 (CUC2), and MIR164 change in cuc1-1D and in hws-1 mutants; analyses revealed a role for HWS in cell proliferation and control of floral organ number. Additional genetic crosses between hws-1 and mutant lines for genes in the miRNA pathway were performed and double mutants obtained shown restoration of the hws-1 sepal fusion phenotype. Our data propose HWS as a new regulator in miRNA pathway and reveal a role for HWS to control floral organ number and cell proliferation

Thrips Resistance Screening Is Coming of Age: Leaf Position and Ontogeny Are Important Determinants of Leaf-Based Resistance in Pepper

Capsicum is a genus containing important crop species, many of which severely suffer from thrips infestation. Thrips feeding damages leaves and fruits, and often results in virus infections. Only a few insecticides are still effective against thrips, underlining the importance of finding natural resistance in crops. Capsicum is a perennial plant which is usually cultivated for several months, during which time the fruits are harvested. From the young vegetative stage to the mature fruit bearing stage, the plants are at risk to thrips infestation. Constitutive resistance to thrips over the entire ontogenetic development is therefore a key trait for a more sustainable and successful cultivation of the hot and sweet pepper. In addition to ontogeny, leaf position can affect the level of thrips resistance. Pest resistance levels are known to differ between young and old leaves. To our knowledge, no studies have explicitly considered ontogeny and leaf position when screening for constitutive resistance to thrips in Capsicum. In this study we analyze whether ontogeny and leaf position affect leaf-based resistance to Frankliniella occidentalis and Thrips tabaci, in 40 Capsicum accessions, comprising five different species. Our results show that resistance to both thrips species in Capsicum varies with ontogenetic stage. This variation in resistance among ontogenetic stages was not consistent among the accessions. However, accessions with constitutive resistance in both the flowering and fruit ripening stage could be identified. In addition, we found that thrips resistance is overall similar at different leaf positions within the ontogenetic stage. This implies that resistance mechanisms, such as defense compounds, are constitutively present at sufficient levels on all leaf positions. Finally, we found that resistance to F. occidentalis and resistance to T. tabaci were not correlated. This indicates that leaf-based resistance in Capsicum is thrips species-specific. Because of the variation in resistance over ontogeny, identifying Capsicum accessions with resistance over their entire lifespan is challenging. For resistance screening, accounting for leaf position may be less of a concern. To identify the defense mechanisms responsible for thrips resistance, it is important to further analyze and compare resistant and susceptible accessions

Transition of care: experiences and preferences of patients across the primary/secondary interface – a qualitative study

BACKGROUND: Coordination between care providers of different disciplines is essential to improve the quality of care, in particular for patients with chronic diseases. The way in which general practitioners (GP's) and medical specialists interact has important implications for any healthcare system in which the GP plays the role of gatekeeper to specialist care. Patient experiences and preferences have proven to be increasingly important in discussing healthcare policy. The Dutch government initiated the development of a special website with information for patients on performance indicators of hospitals as well as information on illness or treatment.In the present study we focus on the transition of care at the primary - secondary interface with reference to the impact of patients' ability to make choices about their secondary care providers. The purpose of this study is to (a) explore experiences and preferences of patients regarding the transition between primary and secondary care, (b) study informational resources on illness/treatment desired by patients and (c) determine how information supplied could make it easier for the patient to choose between different options for care (hospital or specialist). METHODS: We conducted a qualitative study using semi-structured focus group interviews among 71 patients referred for various indications in the north and west of The Netherlands. RESULTS: Patients find it important that they do not have to wait, that they are taken seriously, and receive adequate and individually relevant information. A lack of continuity from secondary to primary care was experienced. The patient's desire for free choice of type of care did not arise in any of the focus groups. CONCLUSION: Hospital discharge information needs to be improved. The interval between discharge from specialist care and the report of the specialist to the GP might be a suitable performance indicator in healthcare. Patients want to receive information, tailored to their own situation. The need for information, however, is quite variable. Patients do not feel strongly about self-chosen healthcare, contrary to what administrators presently believe

The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT is a new player in the microRNA pathway

In Arabidopsis, the F-box HAWAIIAN SKIRT (HWS) protein is important for organ growth. Loss of function of HWS exhibits pleiotropic phenotypes including sepal fusion. To dissect the HWS role, we EMS-mutagenized hws-1 seeds and screened for mutations that suppress hws-1 associated phenotypes. We identified shs-2 and shs-3 (suppressor of hws-2 and 3) mutants in which the sepal fusion phenotype of hws-1 was suppressed. shs-2 and shs-3 (renamed hst-23/hws-1 and hst-24/hws-1) carry transition mutations that result in premature terminations in the plant homolog of Exportin-5 HASTY (HST), known to be important in miRNA biogenesis, function and transport. Genetic crosses between hws-1 and mutant lines for genes in the miRNA pathway, also suppress the phenotypes associated with HWS loss of function, corroborating epistatic relations between the miRNA pathway genes and HWS. In agreement with these data, accumulation of miRNA is modified in HWS loss or gain of function mutants. Our data propose HWS as a new player in the miRNA pathway, important for plant growth