Basonuclin-2 Requirements for Zebrafish Adult Pigment Pattern Development and Female Fertility

Relatively little is known about the generation of adult form. One complex adult trait that is particularly amenable to genetic and experimental analysis is the zebrafish pigment pattern, which undergoes extensive remodeling during post-embryonic development to form adult stripes. These stripes result from the arrangement of three classes of neural crest-derived pigment cells, or chromatophores: melanophores, xanthophores, and iridophores. Here, we analyze the zebrafish bonaparte mutant, which has a normal early pigment pattern but exhibits a severe disruption to the adult stripe pattern. We show that the bonaparte mutant phenotype arises from mutations in basonuclin-2 (bnc2), encoding a highly conserved, nuclear-localized zinc finger protein of unknown function. We show that bnc2 acts non-autonomously to the melanophore lineage and is expressed by hypodermal cells adjacent to chromatophores during adult pigment pattern formation. In bonaparte (bnc2) mutants, all three types of chromatophores differentiate but then are lost by extrusion through the skin. We further show that while bnc2 promotes the development of two genetically distinct populations of melanophores in the body stripes, chromatophores of the fins and scales remain unaffected in bonaparte mutants, though a requirement of fin chromatophores for bnc2 is revealed in the absence of kit and colony stimulating factor-1 receptor activity. Finally, we find that bonaparte (bnc2) mutants exhibit dysmorphic ovaries correlating with infertility and bnc2 is expressed in somatic ovarian cells, whereas the related gene, bnc1, is expressed within oocytes; and we find that both bnc2 and bnc1 are expressed abundantly within the central nervous system. These findings identify bnc2 as an important mediator of adult pigment pattern formation and identify bonaparte mutants as an animal model for dissecting bnc2 functions

Bacterial Cyclic Diguanylate Signaling Networks Sense Temperature

Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, we identify a thermosensory diguanylate cyclase (TdcA) that modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen Pseudomonas aeruginosa. TdcA synthesizes c-di-GMP with catalytic rates that increase more than a hundred-fold over a ten-degree Celsius change. Analyses using protein chimeras indicate that heat-sensing is mediated by a thermosensitive Per-Arnt-SIM (PAS) domain. TdcA homologs are widespread in sequence databases, and a distantly related, heterologously expressed homolog from the Betaproteobacteria order Gallionellales also displayed thermosensitive diguanylate cyclase activity. We propose, therefore, that thermotransduction is a conserved function of c-di-GMP signaling networks, and that thermosensitive catalysis of a second messenger constitutes a mechanism for thermal sensing in bacteria

Colorectal cancer surgery for obese patients:Financial and clinical outcomes of a Dutch population-based registry

Background and Objectives The objective of this study was to explore the association among adverse events, body mass index (BMI), and hospital costs after colorectal cancer surgery in a country with an intermediate BMI distribution. Methods All colorectal cancer procedures in 29 Dutch hospitals listed in a 2010-2012 population-based database and with a BMI > 18.5 were included (n = 8687). Hospital costs were measured uniformly and based on time-driven activity-based costing. The BMI classification of the World Health Organization was used. Results Patients in obesity classes 1 (23.6% [after risk-adjustment OR 1.245, CI 1.064-1.479, P = 0.007]) and =2 (28.1% [after risk-adjustment OR 1.816, CI 1.382-2.388, P < 0.001]) were associated with more severe complications and higher hospital costs (€14,294, +9.6%, after risk-adjustment +7.9%, P < 0.001; and €15,913 +22.0%, after risk-adjustment +21.2%, P < 0.001, respectively) than normal weight patients (20.8% and €13,040, respectively). Pre-obese patients had significantly lower mortality rates (2.7%, after risk-adjustment, OR 0.756, CI 0.577-0.991, P = 0.042) than normal-weight patients (3.9%). Conclusions Obese surgical colorectal cancer patients in a country with an intermediate BMI distribution are associated with a significant increase in hospital costs because these patients suffer from more severe complications. This is the first study to provide evidence for the "obesity-paradox" for mortality in colorectal cancer surgery

Comparative Analysis of Human Nucleoside Kinase-Based Reporter Systems for PET Imaging

PURPOSE: Radionuclide-based reporter gene imaging has the sensitivity to monitor gene- and cell-based therapies in human subjects. Potential immunogenicity of current viral transgenes warrants development of human-based reporter systems. We compared human nucleoside kinase reporters to a panel of nucleoside analogs of FEAU, FMAU, and FIAU, including the first in vivo assessment of L-[(18)F]FEAU. PROCEDURES: Human isogenic U87 cell lines were transduced to express different human reporter genes including dCK-R104M/D133A (dCKDM), dCK-R104Q/D133N (dCKep16A), dCK-A100V/R104M/D133A (dCK3M), and TK2-N93D/L109F (TK2DM), and wild-type dCK (dCK) and herpes simplex virus type-1 (HSVTK) reporter gene as references. In vitro cell uptake assays were performed with [(18)F]FEAU, L-[(18)F]FEAU, [(14)C]FMAU, L-[(18)F]FMAU, and [(124)I]FIAU. Micro-positron emission tomography/X-ray computed tomography imaging of xenograft-bearing nu/nu mice was conducted with [(18)F]FEAU, L-[(18)F]FEAU, L-[(18)F]FMAU, and [(124)I]FIAU on consecutive days. A cell viability assay was also performed to assess sensitivities to gemcitabine and bromovinyldeoxyuridine (BVdU). RESULTS: In vitro, dCKep16A and dCKDM with [(18)F]FEAU exhibited the highest sensitivity and selectivity of the human reporters, second only to HSVTK/[(18)F]FEAU. L-[(18)F]FEAU biodistribution in mice was on par with [(18)F]FEAU and L-[(18)F]FMAU. L-[(18)F]FMAU uptake in isogenic xenografts was highest for all human reporter genes. However, [(18)F]FEAU was the most selective of the short half-life reporter probes due to its minimal recognition by human dCK and relative sensitivity, whereas [(124)I]FIAU permitted imaging at a later time point, improving signal-to-background ratio. Of the human reporter genes, dCKep16A consistently outperformed the other tested reporters. Reporter genes of interest increased potency to the nucleoside analog prodrugs gemcitabine and BVdU. CONCLUSIONS: We demonstrate that human nucleoside kinase reporter systems vary significantly in their sensitivity and selectivity for in vivo imaging. The sufficiently high signal-to-background ratios and enhanced suicide gene potential support clinical translation

Proarrhythmia in a non-failing murine model of cardiac-specific Na+/Ca2+ exchanger overexpression: whole heart and cellular mechanisms

The cardiac Na(+)/Ca(2+) exchanger (NCX) generates an inward electrical current during SR-Ca(2+) release, thus possibly promoting afterdepolarizations of the action potential (AP). We used transgenic mice 12.5 weeks or younger with cardiomyocyte-directed overexpression of NCX (NCX-Tg) to study the proarrhythmic potential and mechanisms of enhanced NCX activity. NCX-Tg exhibited normal echocardiographic left ventricular function and heart/body weight ratio, while the QT interval was prolonged in surface ECG recordings. Langendorff-perfused NCX-Tg, but not wild-type (WT) hearts, developed ventricular tachycardia. APs and ionic currents were measured in isolated cardiomyocytes. Cell capacitance was unaltered between groups. APs were prolonged in NCX-Tg versus WT myocytes along with voltage-activated K(+) currents (K(v)) not being reduced but even increased in amplitude. During abrupt changes in pacing cycle length, early afterdepolarizations (EADs) were frequently recorded in NCX-Tg but not in WT myocytes. Next to EADs, delayed afterdepolarizations (DAD) triggering spontaneous APs (sAPs) occurred in NCX-Tg but not in WT myocytes. To test whether sAPs were associated with spontaneous Ca(2+) release (sCR), Ca(2+) transients were recorded. Despite the absence of sAPs in WT, sCR was observed in myocytes of both genotypes suggesting a facilitated translation of sCR into DADs in NCX-Tg. Moreover, sCR was more frequent in NCX-Tg as compared to WT. Myocardial protein levels of Ca(2+)-handling proteins were not different between groups except the ryanodine receptor (RyR), which was increased in NCX-Tg versus WT. We conclude that NCX overexpression is proarrhythmic in a non-failing environment even in the absence of reduced K(V). The underlying mechanisms are: (1) occurrence of EADs due to delayed repolarization; (2) facilitated translation from sCR into DADs; (3) proneness to sCR possibly caused by altered Ca(2+) handling and/or increased RyR expression