LifeMap Discovery?: The Embryonic Development,Stem Cells,and Regenerative Medicine Research Portal

LifeMap Discovery™ provides investigators with an integrated database of embryonic development, stem cell biology and regenerative medicine. The hand-curated reconstruction of cell ontology with stem cell biology; including molecular, cellular, anatomical and disease-related information, provides efficient and easy-to-use, searchable research tools. The database collates in vivo and in vitro gene expression and guides translation from in vitro data to the clinical utility, and thus can be utilized as a powerful tool for research and discovery in stem cell biology, developmental biology, disease mechanisms and therapeutic discovery. LifeMap Discovery is freely available to academic nonprofit institutions at http://discovery.lifemapsc.com     

Ongoing Pregnancy Rates in Women with Low and Extremely Low AMH Levels. A Multivariate Analysis of 769 Cycles

Background

The ideal test for ovarian reserve should permit the identification of women who have no real chance of pregnancy with IVF treatments consequent upon an extremely reduced ovarian reserve. The aim of the current study was to evaluate pregnancy rates in patients with low AMH levels (0.2–1 ng/ml) and extremely low AMH levels (<0.2 ng/ml) and to determine the cumulative pregnancy rates following consecutive IVF treatments.

Methods

We conducted an historical cohort analysis at a tertiary medical center. Serum AMH levels were measured at initial clinic visit and prior to all following treatment cycles in 181 women (769 cycles) with an initial AMH level ≤1 ng/ml, undergoing IVF-ICSI. Main outcome measures were laboratory outcomes and pregnancy rates.

Results

Seventy patients undergoing 249 cycles had extremely low AMH levels (≤0.2 ng/ml), whereas 111 patients undergoing 520 cycles had low AMH levels (0.21–1.0 ng/ml). Number of oocytes retrieved per cycle, fertilized oocytes and number of transferred embryos were significantly lower in the extremely low AMH levels group compared to the low AMH levels (P<0.003). Crude ongoing pregnancy rates were 4.4% for both groups of patients. Among 48 cycles of women aged ≥42 with AMH levels of ≤0.2 ng/ml no pregnancies were observed. But, in patients with AMH levels of 0.2–1.0 ng/ml, 3 ongoing pregnancies out of 192 cycles (1.6%) were observed. However, in a multivariate regression analysis adjusted for age and cycle characteristics, no significant differences in ongoing pregnancy rates per cycle between the two groups were evident. Cumulative pregnancy rates of 20% were observed following five cycles, for both groups of patients.

Conclusions

Patients with extremely low AMH measurements have reasonable and similar pregnancy rates as patients with low AMH. Therefore, AMH should not be used as the criterion to exclude couples from performing additional IVF treatments.     

Genome-wide association mapping of agronomic traits in relevant barley germplasm in Uruguay

The genetic basis of agronomic traits determining adaptation to specific production conditions is a key factor for the improvement of crops, including malting barley (Hordeum vulgare L.). The aim of this study was to determine the genome-wide genetic components associated with agronomic phenotypes of local and global significance in a population of 76 barley genotypes that have been introduced into Uruguay in different chronological periods. The phenotypic database was obtained from five field experiments, planted in 2 years and in two locations, where a total of 13 agronomic traits were determined. The population was genotyped with 1,033 single nucleotide polymorphisms. We found a total of 41 quantitative trait loci (QTL) in a combined analysis using all datasets and 79 QTL if we considered all the trait/experiment combinations analyzed. The highest concentration of QTL was detected on chromosomes 2H and 4H. Most QTL were detected for grain plumpness and weight. Two linkage disequilibrium (LD) blocks associated with a large number of traits were detected on 2HS. The largest LD block was composed of three haplotypes, possibly derived from three ancestors of different geographical origin. We also detected three genomic regions in different chromosomes (2H, 5H and 7H) in LD between them, associated with agronomic traits. This study provides a contribution to the understanding of the genetics of barley adaptation in the southern cone of South America. Our results showed that elite varieties have favorable alleles at different QTL, indicating that gains can be made through plant breeding.     

Environmental Stresses Disrupt Telomere Length Homeostasis

Telomeres protect the chromosome ends from degradation and play crucial roles in cellular aging and disease. Recent studies have additionally found a correlation between psychological stress, telomere length, and health outcome in humans. However, studies have not yet explored the causal relationship between stress and telomere length, or the molecular mechanisms underlying that relationship. Using yeast as a model organism, we show that stresses may have very different outcomes: alcohol and acetic acid elongate telomeres, whereas caffeine and high temperatures shorten telomeres. Additional treatments, such as oxidative stress, show no effect. By combining genome-wide expression measurements with a systematic genetic screen, we identify the Rap1/Rif1 pathway as the central mediator of the telomeric response to environmental signals. These results demonstrate that telomere length can be manipulated, and that a carefully regulated homeostasis may become markedly deregulated in opposing directions in response to different environmental cues.     

Induced pluripotent stem cells' self-renewal and pluripotency is maintained by a bovine granulosa cell line-conditioned medium

Senescence marker protein-30 (SMP30) plays an important role in intracellular Ca²⁺ homeostasis. The aim of the present study was to investigate the effects of estrogens on liver apoptotic damage and changes in SMP30 expression induced by a high saturated fatty acid diet (HSFD). Ovariectomized mice (OVX) and sham-operated mice (SHAM) were randomly divided into five groups: SHAM fed a normal diet (SHAM/ND), SHAM fed HSFD (SHAM/HSFD), OVX fed ND (OVX/ND), OVX fed HSFD (OVX/HSFD) and OVX fed HSFD with 17β-estradiol (E2) supplementation using an implanted slow-release pellet (OVX/HSFD + E2). After 8 weeks, markers of endoplasmic reticulum (ER) stress and apoptosis, and levels of tumor necrosis factor-α (TNFα and SMP30 expression were investigated. Compared with SHAM/ND, OVX/HSFD mice showed significantly increased spliced X-box protein-1 (s-XBP1), phosphorylated eukaryotic initiation factor-2α (p-eIF2α), glucose-regulated protein 78 (GPR78), C/EBP homologous protein (CHOP), cytosolic cytochrome c, caspase-3 activity, and TNFα, and significantly decreased SMP30. These differences in OVX/HSFD mice were restored to the levels of SHAM/ND mice by E2 supplementation. These results suggest that E2 supplementation attenuates HSFD-induced liver apoptotic death in ovariectomized mice by up-regulating SMP30.     

Genome sequence of the 1,4-dioxane-degrading Pseudonocardia dioxanivorans strain CB1190

Pseudonocardia dioxanivorans CB1190 is the first bacterium reported to be capable of growth on the environmental contaminant 1,4-dioxane and the first member of the genus Pseudonocardia for which there is an annotated genome sequence. Preliminary analysis of the genome (chromosome and three plasmids) indicates that strain CB1190 possesses several multicomponent monooxygenases that could be involved in the aerobic degradation of 1,4-dioxane and other environmental contaminants.     

The Epstein-Barr virus BRRF1 protein, Na, induces lytic infection in a TRAF2- and p53-dependent manner

The Epstein-Barr virus (EBV) BRRF1 lytic gene product (Na) is encoded within the same immediate-early region as the BZLF1 (Z) and BRLF1(R) gene products, but its role during EBV infection has not been well defined. We previously showed that Na cooperates with the R protein to induce lytic gene expression in latently infected EBV-positive 293 cells, and in some EBV-negative cell lines it can activate the Z promoter in reporter gene assays. Here we show that overexpression of Na alone is sufficient to induce lytic gene expression in several different latently infected epithelial cell lines (Hone-Akata, CNE2-Akata, and AGS-Akata), while knockdown of endogenous Na expression reduces lytic gene expression. Consistent with its ability to interact with tumor necrosis factor receptor-associated factor 2 (TRAF2) in a yeast two-hybrid assay, we demonstrate that Na interacts with TRAF2 in cells. Furthermore, we show that TRAF2 is required for Na induction of lytic gene expression, that Na induces Jun N-terminal protein kinase (JNK) activation in a TRAF2-dependent manner, and that a JNK inhibitor abolishes the ability of Na to disrupt viral latency. Additionally, we show that Na and the tumor suppressor protein p53 cooperate to induce lytic gene expression in epithelial cells (including the C666-1 nasopharyngeal carcinoma cell line), although Na does not appear to affect p53 function. Together these data suggest that Na plays an important role in regulating the switch between latent and lytic infection in epithelial cells and that this effect requires both the TRAF2 and p53 cellular proteins.     

Mutation of conserved tryptophan residues at the dimer interface of Staphylococcus aureus nitric oxide synthase

Nitric oxide synthases (NOSs) share two invariant tryptophan residues within a conserved helical lariat that is part of the pterin-binding site and dimer interface. We mutated Staphylococcus aureus NOS Trp-314 (to alanine, phenylalanine, tyrosine and histidine) and Trp-316 (to alanine, phenylalanine and tyrosine) and characterized the effects of mutation on heme environment, quaternary structure, enzymatic activity, and substrate affinity. With arginine present, all saNOS variants bound heme with native thiolate ligation, formed high spin ferric complexes and were dimeric. All variants catalyze the peroxide-dependent oxidation of N-hydroxy-l-arginine, at rates from 10% to 55% of wild type activity. Arginine-free proteins are dimeric with the exception of W314A. Arginine affinity for all variants decreases with increasing temperature between 15 and 42 °C but is precipitous for position-314 variants. Previous structural and biophysical characterization of NOS oxygenase domains demonstrated that the protein can exist in either a tight or loose conformation, with the former corresponding to the active state of the protein. In the position-314 variants it is likely that the loose conformation is favoured, owing to the loss of a hydrogen bond between the indole side chain and the polypeptide backbone of the helical lariat.