Confirmation of the potential usefulness of two human beta globin pseudogene markers to estimate gene flows to and from sub-Saharan Africans

Two polymorphic sites, -107 and -100 with respect to the "cap" site of the human beta globin pseudogene, recently discovered in our laboratory, turned out to have an ethnically complementary distribution. The first site is polymorphic in Europeans, North Africans, Indians (Hindu), and Oriental Asians, and monomorphic in sub-Saharan Africans. Conversely, the second site is polymorphic in sub-Saharan African populations and monomorphic in the aforementioned populations. Here we report the gene frequencies of these two polymorphic sites in nine additional populations (Egyptians, Spaniards, Japanese, Chinese, Filipinos, Vietnamese, Africans from Togo and from Benin, and Pygmies), confirming their ethnospecificity and, through the analysis of these two markers in Oromo and Amhara of Ethiopia (two mixed populations), their usefulness in genetic admixture studies. Moreover, we studied another marker polymorphic in sub-Saharan African populations only, a TaqI restriction fragment length polymorphism located in the same region as the present markers, demonstrating the absence of linkage disequilibrium between it and the -100 site, so that we can exclude that the information they provide is redundant.     

Investigation of Four Classes of Non-nodulating White Sweetclover (Melilotus alba annua Desr.) Mutants and Their Responses to Arbuscular-Mycorrhizal Fungi

The nitrogen-fixing symbiosis between Rhizobiaceae and legumes is one of the best-studied interactions established between prokaryotes and eukaryotes. The plant develops root nodules in which the bacteria are housed, and atmospheric nitrogen is fixed into ammonia by the rhizobia and made available to the plant in exchange for carbon compounds. It has been hypothesized that this symbiosis evolved from the more ancient arbuscular mycorrhizal (AM) symbiosis, in which the fungus associates with roots and aids the plant in the absorption of mineral nutrients, particularly phosphate. Support comes from several fronts: 1) legume mutants where Nod(-) and Myc(-) co-segregate, and 2) the fact that various early nodulin (ENOD) genes are expressed in legume AM. Both strongly argue for the idea that the signal transduction pathways between the two symbioses are conserved. We have analyzed the responses of four classes of non-nodulating Melilotus alba (white sweetclover) mutants to Glomus intraradices (the mycorrhizal symbiont) to investigate how Nod(-) mutations affect the establishment of this symbiosis. We also re-examined the root hair responses of the non-nodulating mutants to Sinorhizobium meliloti (the nitrogen-fixing symbiont). Of the four classes, several sweetclover sym mutants are both Nod(-) and Myc(-). In an attempt to decipher the relationship between nodulation and mycorrhiza formation, we also performed co-inoculation experiments with mutant rhizobia and Glomus intraradices on Medicago sativa, a close relative of M. alba. Even though sulfated Nod factor was supplied by some of the bacterial mutants, the fungus did not complement symbiotically defective rhizobia for nodulation.     

Potential role for ADAM15 in pathological neovascularization in mice

ADAM15 (named for a disintegrin and metalloprotease 15, metargidin) is a membrane-anchored glycoprotein that has been implicated in cell-cell or cell-matrix interactions and in the proteolysis of molecules on the cell surface or extracellular matrix. To characterize the potential roles of ADAM15 during development and in adult mice, we analyzed its expression pattern by mRNA in situ hybridization and generated mice carrying a targeted deletion of ADAM15 (adam15(-/-) mice). A high level of expression of ADAM15 was found in vascular cells, the endocardium, hypertrophic cells in developing bone, and specific areas of the hippocampus and cerebellum. However, despite the pronounced expression of ADAM15 in these tissues, no major developmental defects or pathological phenotypes were evident in adam15(-/-) mice. The elevated levels of ADAM15 in endothelial cells prompted an evaluation of its role in neovascularization. In a mouse model for retinopathy of prematurity, adam15(-/-) mice had a major reduction in neovascularization compared to wild-type controls. Furthermore, the size of tumors resulting from implanted B16F0 mouse melanoma cells was significantly smaller in adam15(-/-) mice than in wild-type controls. Since ADAM15 does not appear to be required for developmental angiogenesis or for adult homeostasis, it may represent a novel target for the design of inhibitors of pathological neovascularization.     

Consistency of SINE insertion topology and flanking sequence tree: quantifying relationships among cetartiodactyls

Short interspersed nuclear elements (SINEs) have been used to generate unambiguous phylogenetic topologies relating eukaryotic taxa. The irreversible nature of SINE retroposition is supported by a large body of comparative genome data and is a fundamental assumption inherent in the value of this qualitative method of inference. Here, we assess the key assumption of unidirectional SINE insertion by comparing the SINE insertion-derived topology and the phylogenetic tree based on seven independent loci of five taxa in the order Cetartiodactyla (Cetacea + Artiodactyla). The data sets and analyses were largely independent, but the loci were, by definition, linked, and thus their consistency supported an irreversible pattern of SINE retroposition. Moreover, our analyses of the flanking sequences provided estimates of divergence times among cetartiodactyl lineages unavailable from SINE insertion analysis alone. Unexpected rate heterogeneity among sites of SINE-flanking sequences and other noncoding DNA sequences were observed. Sequence simulations suggest that this rate heterogeneity may be an artifact resulting from the inaccuracies of the substitution model used.     

Dynamic creep and pre-conditioning of the Achilles tendon in-vivo

Warm-up exercises are often advocated prior to strenuous exercise, but the warm-up duration and effect on muscle–tendon behavior are not well defined. The gastrocnemius–Achilles tendon complexes of 18 subjects were studied to quantify the dynamic creep response of the Achilles tendon in-vivo and the warm-up dose required for the Achilles tendon to achieve steady-state behavior. A custom testing chamber was used to determine each subject's maximum voluntary contraction (MVC) during an isometric ankle plantar flexion effort. The subject's right knee and ankle were immobilized for one hour. Subjects then performed over seven minutes of cyclic isometric ankle plantar flexion efforts equal to 25–35% of their MVC at a frequency of 0.75 Hz. Ankle plantar flexion effort and images from dual ultrasound probes located over the gastrocnemius muscle–Achilles tendon and the calcaneus–Achilles tendon junction were acquired for eight seconds at the start of each sequential minute of the activity. Ultrasound images were analyzed to quantify the average relative Achilles tendon strain at 25% MVC force (ε_25%MVC) for each minute. The ε_25%MVC increased from 0.3% at the start of activity to 3.3% after seven minutes, giving a total dynamic creep of ~3.0%. The ε_25%MVC increased by more than 0.56% per minute for the first five minutes and increased by less than 0.13% per minute thereafter. Therefore, following a period of inactivity, a low intensity warm-up lasting at least six minutes or producing 270 loading cycles is required for an Achilles tendon to reach a relatively steady-state behavior.     

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.     

Identification of the IL-17 receptor related molecule IL-17RC as the receptor for IL-17F

The proinflammatory cytokines IL-17A and IL-17F have a high degree of sequence similarity and share many biological properties. Both have been implicated as factors contributing to the progression of inflammatory and autoimmune diseases. Moreover, reagents that neutralize IL-17A significantly ameliorate disease severity in several mouse models of human disease. IL-17A mediates its effects through interaction with its cognate receptor, the IL-17 receptor (IL-17RA). We report here that the IL-17RA-related molecule, IL-17RC is the receptor for IL-17F. Notably, both IL-17A and IL-17F bind to IL-17RC with high affinity, leading us to suggest that a soluble form of this molecule may serve as an effective therapeutic antagonist of IL-17A and IL-17F. We generated a soluble form of IL-17RC and demonstrate that it effectively blocks binding of both IL-17A and IL-17F, and that it inhibits signaling in response to these cytokines. Collectively, our work indicates that IL-17RC functions as a receptor for both IL-17A and IL-17F and that a soluble version of this protein should be an effective antagonist of IL-17A and IL-17F mediated inflammatory diseases.     

Virtual reality of stem cell transplantation to repair injured myocardium

The search for the fountain of youth continues into the 21st century with hopes that embryonic or hematopoietic stem cells (SC) will repair injured tissues in the heart, lungs, pancreas, muscles, nerves, liver, or skin. This commentary focuses on the potential of SC for inducing cardiac regeneration after myocardial injury, the barriers to SC treatment that need to be overcome for ensuring successful cardiac repair, and the experimental approaches that can be applied to the problem.