Effects of curcumin on methyl methanesulfonate damage to mouse kidney

Methylmethane sulfonate (MMS) is an alkylating agent that may react with DNA and damage it. We investigated histological changes and apoptosis caused by MMS and the effects of curcumin on MMS treated mouse kidneys. Twenty-four mice were divided into four equal groups: controls injected with saline, a group injected with 40 mg/kg MMS, a group injected with 40 mg/kg MMS and given 100 mg/kg curcumin by gavage, and a group given 100 mg/kg curcumin by gavage. MMS caused congestion and vacuole formation, and elevated the apoptotic index significantly, but had no other effect on kidney tissue. Curcumin improved the congestion and vacuole formation caused by MMS and decreased the apoptotic index. Curcumin administered with MMS appears to decrease the deleterious effects of MMS on the kidney.     

The evolution of microendemism in a reef fish (Hypoplectrus maya)

Marine species tend to have extensive distributions, which are commonly attributed to the dispersal potential provided by planktonic larvae and the rarity of absolute barriers to dispersal in the ocean. Under this paradigm, the occurrence of marine microendemism without geographic isolation in species with planktonic larvae poses a dilemma. The recently described Maya hamlet (Hypoplectrus maya, Serranidae) is exactly such a case, being endemic to a 50‐km segment of the Mesoamerican Barrier Reef System (MBRS). We use whole‐genome analysis to infer the demographic history of the Maya hamlet and contrast it with the sympatric and pan‐Caribbean black (H. nigricans), barred (H. puella) and butter (H. unicolor) hamlets, as well as the allopatric but phenotypically similar blue hamlet (H. gemma). We show that H. maya is indeed a distinct evolutionary lineage, with genomic signatures of inbreeding and a unique demographic history of continuous decrease in effective population size since it diverged from congeners just ~3,000 generations ago. We suggest that this case of microendemism may be driven by the combination of a narrow ecological niche and restrictive oceanographic conditions in the southern MBRS, which is consistent with the occurrence of an unusually high number of marine microendemics in this region. The restricted distribution of the Maya hamlet, its decline in both census and effective population sizes, and the degradation of its habitat place it at risk of extinction. We conclude that the evolution of marine microendemism can be a fast and dynamic process, with extinction possibly occurring before speciation is complete.     

Essential functions of Alk3 during AV cushion morphogenesis in mouse embryonic hearts

Accumulated evidence has suggested that BMP pathways play critical roles during mammalian cardiogenesis and impairment of BMP signaling may contribute to human congenital heart diseases (CHDs), which are the leading cause of infant morbidity and mortality. Alk3 encodes a BMP specific type I receptor expressed in mouse embryonic hearts. To reveal functions of Alk3 during atrioventricular (AV) cushion morphogenesis and to overcome the early lethality of Alk3(-/-) embryos, we applied a Cre/loxp approach to specifically inactivate Alk3 in the endothelium/endocardium. Our studies showed that endocardial depletion of Alk3 severely impairs epithelium-mesenchymal-transformation (EMT) in the atrioventricular canal (AVC) region; the number of mesenchymal cells formed in Tie1-Cre;Alk3(loxp/loxp) embryos was reduced to only approximately 20% of the normal level from both in vivo section studies and in vitro explant assays. We showed, for the first time, that in addition to its functions on mesenchyme formation, Alk3 is also required for the normal growth/survival of AV cushion mesenchymal cells. Functions of Alk3 are accomplished through regulating expression/activation/subcellular localization of multiple downstream genes including Smads and cell-cycle regulators. Taken together, our study supports the notion that Alk3-mediated BMP signaling in AV endocardial/mesenchymal cells plays a central role during cushion morphogenesis.     

Fundulus as the premier teleost model in environmental biology: opportunities for new insights using genomics

A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms.     

Assessing the significance of conserved genomic aberrations using high resolution genomic microarrays

Genomic aberrations recurrent in a particular cancer type can be important prognostic markers for tumor progression. Typically in early tumorigenesis, cells incur a breakdown of the DNA replication machinery that results in an accumulation of genomic aberrations in the form of duplications, deletions, translocations, and other genomic alterations. Microarray methods allow for finer mapping of these aberrations than has previously been possible; however, data processing and analysis methods have not taken full advantage of this higher resolution. Attention has primarily been given to analysis on the single sample level, where multiple adjacent probes are necessarily used as replicates for the local region containing their target sequences. However, regions of concordant aberration can be short enough to be detected by only one, or very few, array elements. We describe a method called Multiple Sample Analysis for assessing the significance of concordant genomic aberrations across multiple experiments that does not require a-priori definition of aberration calls for each sample. If there are multiple samples, representing a class, then by exploiting the replication across samples our method can detect concordant aberrations at much higher resolution than can be derived from current single sample approaches. Additionally, this method provides a meaningful approach to addressing population-based questions such as determining important regions for a cancer subtype of interest or determining regions of copy number variation in a population. Multiple Sample Analysis also provides single sample aberration calls in the locations of significant concordance, producing high resolution calls per sample, in concordant regions. The approach is demonstrated on a dataset representing a challenging but important resource: breast tumors that have been formalin-fixed, paraffin-embedded, archived, and subsequently UV-laser capture microdissected and hybridized to two-channel BAC arrays using an amplification protocol. We demonstrate the accurate detection on simulated data, and on real datasets involving known regions of aberration within subtypes of breast cancer at a resolution consistent with that of the array. Similarly, we apply our method to previously published datasets, including a 250K SNP array, and verify known results as well as detect novel regions of concordant aberration. The algorithm has been fully implemented and tested and is freely available as a Java application at http://www.cbil.upenn.edu/MSA.     

VEGF receptor 2/‐3 heterodimers detected in situ by proximity ligation on angiogenic sprouts

The vascular endothelial growth factors VEGFA and VEGFC are crucial regulators of vascular development. They exert their effects by dimerization and activation of the cognate receptors VEGFR2 and VEGFR3. Here, we have used in situ proximity ligation to detect receptor complexes in intact endothelial cells. We show that both VEGFA and VEGFC potently induce formation of VEGFR2/‐3 heterodimers. Receptor heterodimers were found in both developing blood vessels and immature lymphatic structures in embryoid bodies. We present evidence that heterodimers frequently localize to tip cell filopodia. Interestingly, in the presence of VEGFC, heterodimers were enriched in the leading tip cells as compared with trailing stalk cells of growing sprouts. Neutralization of VEGFR3 to prevent heterodimer formation in response to VEGFA decreased the extent of angiogenic sprouting. We conclude that VEGFR2/‐3 heterodimers on angiogenic sprouts induced by VEGFA or VEGFC may serve to positively regulate angiogenic sprouting.     

Selective, high-affinity binding of ferric ions by glycine-extended gastrin(17)

Uptake of dietary iron is essential for replenishment of body stores. A role for the hormone gastrin in iron uptake as a chelator of ferric ions in the gastric lumen has been proposed previously [Baldwin, G. S. (1992) Med. Hypotheses 38, 70-74]. Here, spectroscopic evidence of selective, high-affinity binding of ferric ions to progastrin-derived peptides in aqueous solution at low pH is provided. The maximum at 281 nm in the absorption spectrum of glycine-extended gastrin(17) at pH 4.0 increased (2.07 +/- 0.30)-fold in the presence of > or =2 equiv of ferric ions. Titration of glycine-extended gastrin(17) with ferric ions under stoichiometric conditions indicated that the stoichiometry of binding was 2.00 +/- 0.28 mol of Fe(3+)/mol of peptide. Fluorescence quenching experiments yielded values for the stoichiometry and apparent dissociation constant of the ferric ion-glycine-extended gastrin(17) complex at pH 4.0 of 2.39 +/- 0.17 mol of Fe(3+)/mol and 0.62 +/- 0.19 microM, respectively. No interaction was detected with Co(2+), Cu(2+), Mn(2+), or Cr(3+). Electron paramagnetic resonance spectroscopy suggested that the iron ligands were either oxygen or sulfur atoms. Fluorescence quenching experiments with peptides derived from the glycine-extended gastrin(17) sequence indicated that one or more of the five glutamic acid residues were necessary for iron binding. The binding of ferric ions by glycine-extended gastrin(17) at low pH is consistent with a role for progastrin-derived peptides in iron uptake from the lumen of the gastrointestinal tract.