Marked Increase in PROP Taste Responsiveness Following Oral Supplementation with Selected Salivary Proteins or Their Related Free Amino Acids

The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by ¹H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.¹H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting.     

The ubiquitin-interacting motifs target the endocytic adaptor protein epsin for ubiquitination

The covalent attachment of ubiquitin to proteins is an evolutionarily conserved signal for rapid protein degradation. However, additional cellular functions for ubiquitination are now emerging, including regulation of protein trafficking and endocytosis. For example, recent genetic studies suggested a role for ubiquitination in regulating epsin, a modular endocytic adaptor protein that functions in the assembly of clathrin-coated vesicles; however, biochemical evidence for this notion has been lacking. Epsin consists of an epsin NH(2)-terminal homology (ENTH) domain that promotes the interaction with phospholipids, several AP2 binding sites, two clathrin binding sequences, and several Eps15 homology (EH) domain binding motifs. Interestingly, epsin also possesses several recently described ubiquitin-interacting motifs (UIMs) that have been postulated to bind ubiquitin. Here, we demonstrate that epsin is predominantly monoubiquitinated and resistant to proteasomal degradation. The UIMs are necessary for epsin ubiquitination but are not the site of ubiquitination. Finally, we demonstrate that the isolated UIMs from both epsin and an unrelated monoubiquitinated protein, Eps15, are sufficient to promote ubiquitination of a chimeric glutathione-S-transferase (GST)-UIM fusion protein. Thus, our data suggest that UIMs may serve as a general signal for ubiquitination.     

Solar radiation decreases parasitism in Daphnia

Climate change and variation in atmospheric ozone are influencing the intensity of ultraviolet radiation (UVR) reaching ecosystems. Changing UVR regimes, in turn, may alter epidemics of infectious disease. This possibility hinges on the sensitivity of epidemiologically relevant traits of host and parasite to UVR. We address this issue using a planktonic system (a zooplankton host, Daphnia dentifera, and its virulent fungal parasite, Metschnikowia bicuspidata). Controlled laboratory experiments, coupled with in situ field incubations of spores, revealed that quite low levels of UVR (as well as longer wavelength light) sharply reduced the infectivity of fungal spores but did not affect host susceptibility to infection. The parasite's sensitivity to solar radiation may underlie patterns in a lake survey: higher penetration of solar radiation into lakes correlated with smaller epidemics that started later in autumn (as incident sunlight declined). Thus, solar radiation, by diminishing infectivity of the parasite, may potently reduce disease.     

Nutrient recycling by insect and fish communities in high-elevation tropical streams

Hydrobiologia - High- to mid-elevation streams are often oligotrophic, but harbor diverse groups of aquatic animals that can satisfy a substantial proportion of nutrient demand. Therefore, we...     

Personalized Oncogenomics: Clinical Experience with Malignant Peritoneal Mesothelioma Using Whole Genome Sequencing

Peritoneal mesothelioma is a rare and sometimes lethal malignancy that presents a clinical challenge for both diagnosis and management. Recent studies have led to a better understanding of the molecular biology of peritoneal mesothelioma. Translation of the emerging data into better treatments and outcome is needed. From two patients with peritoneal mesothelioma, we derived whole genome sequences, RNA expression profiles, and targeted deep sequencing data. Molecular data were made available for translation into a clinical treatment plan. Treatment responses and outcomes were later examined in the context of molecular findings. Molecular studies presented here provide the first reported whole genome sequences of peritoneal mesothelioma. Mutations in known mesothelioma-related genes NF2, CDKN2A, LATS2, amongst others, were identified. Activation of MET-related signaling pathways was demonstrated in both cases. A hypermutated phenotype was observed in one case (434 vs. 18 single nucleotide variants) and was associated with a favourable outcome despite sarcomatoid histology and multifocal disease. This study represents the first report of whole genome analyses of peritoneal mesothelioma, a key step in the understanding and treatment of this disease.     

Pre-adipocytes commitment to neurogenesis 1: Preliminary localisation of cholinergic molecules

A great effort has recently been made to obtain human stem cells able to differentiate into cholinergic neurons, as a number of diseases are associated to the cholinergic neuron loss, degeneration or incorrect function (Alzheimer's disease and motor neuron disease). A stem cell population (i.e. pre-adipocytes) is present in the adipose stromal compartment. Pre-adipocytes, like the mesodermic derivative cells, retain high plasticity and potentiality to convert in vitro from one phenotype into many others, and they can be isolated from adult adipose tissue. Pre-adipocytes committed in vitro to neural differentiation were followed up to the acquisition of neural morphology. Acetylcholinesterase and choline acetyltransferase are expressed from the native cell stage, with different localisations and roles during neural commitment. Western blots show the beginning of a new synthesis of these enzymes at 4 weeks of culture of neurogenic pre-adipocytes, in parallel with neural morphology. The passage of the choline-acetyltransferase immunoreactivity from cytoplasmic to membrane localisation shows the possible onset of catalytic activity and the histochemical reaction confirms the activity of acetylcholinesterase. This explains the possibility of obtaining cholinergic-like phenotype from pre-adipocytes.     

Early Transplantation of Bone Marrow Mononuclear Cells Promotes Neuroprotection and Modulation of Inflammation After Status Epilepticus in Mice by Paracrine Mechanisms

Status epilepticus (SE) is a severe clinical manifestation of epilepsy associated with intense neuronal loss and inflammation, two key factors involved in the pathophysiology of temporal lobe epilepsy. Bone marrow mononuclear cells (BMMC) attenuated the consequences of pilocarpine-induced SE, including neuronal loss, in addition to frequency and duration of seizures. Here we investigated the effects of BMMC transplanted early after the onset of SE in mice, as well as the involvement of soluble factors produced by BMMC in the effects of the cell therapy. Mice were injected with pilocarpine for SE induction and randomized into three groups: transplanted intravenously with 1 × 10⁷ BMMC isolated from GFP transgenic mice, injected with BMMC lysate, and saline-treated controls. Cell tracking, neuronal counting in hippocampal subfields and cytokine analysis in the serum and brain were performed. BMMC were found in the brain 4 h following transplantation and their numbers progressively decreased until 24 h following transplantation. A reduction in hippocampal neuronal loss after SE was found in mice treated with live BMMC and BMMC lysate when compared to saline-treated, SE-induced mice. Moreover, the expression of inflammatory cytokines IL-1β, TNF-α, IL-6 was decreased after injection of live BMMC and to a lesser extent, of BMMC lysate, when compared to SE-induced controls. In contrast, IL-10 expression was increased. Analysis of markers for microglia activation demonstrated a reduction of the expression of genes related to type 1-activation. BMMC transplantation promotes neuroprotection and mediates anti-inflammatory effects following SE in mice, possibly through the secretion of soluble factors.     

AHR Over-Expression in Papillary Thyroid Carcinoma: Clinical and Molecular Assessments in a Series of Italian Acromegalic Patients with a Long-Term Follow-Up

Aim

Acromegaly reportedly carries an increased risk of malignant and benign thyroid tumors, with a prevalence of thyroid cancer of around 3–7%. Germline mutations in the aryl-hydrocarbon receptor (AHR) interacting protein (AIP) have been identified in familial forms of acromegaly. The molecular and endocrine relationships between follicular thyroid growth and GH-secreting pituitary adenoma have yet to be fully established. Our aim was to study the prevalence of differentiated thyroid cancer (DTC) in acromegaly, focusing on the role of genetic events responsible for the onset of thyroid cancer.

Methods

Germline mutations in the AIP gene were assessed in all patients; BRAF and H-N-K RAS status was analyzed by direct sequencing in thyroid specimens, while immunohistochemistry was used to analyze the protein expression of AIP and AHR. A set of PTCs unrelated to acromegaly was also studied.

Results

12 DTCs (10 papillary and 2 follicular carcinomas) were identified in a cohort of 113 acromegalic patients. No differences in GH/IGF-1 levels or disease activity emerged between patients with and without DTC, but the former were older and more often female. BRAF V600E was found in 70% of the papillary thyroid cancers; there were no RAS mutations. AIP protein expression was similar in neoplastic and normal cells, while AHR protein was expressed more in PTCs carrying BRAF mutations than in normal tissue, irrespective of acromegaly status.

Conclusions

The prevalence of DTC in acromegaly is around 11% and endocrinologists should bear this in mind, especially when examining elderly female patients with uninodular goiter. The DTC risk does not seem to correlate with GH/IGF-1 levels, while it may be associated with BRAF mutations and AHR over-expression. Genetic or epigenetic events probably play a part in promoting thyroid carcinoma.