Putative "stemness" gene jam-B is not required for maintenance of stem cell state in embryonic, neural, or hematopoietic stem cells

Many genes have been identified that are specifically expressed in multiple types of stem cells in their undifferentiated state. It is generally assumed that at least some of these putative "stemness" genes are involved in maintaining properties that are common to all stem cells. We compared gene expression profiles between undifferentiated and differentiated embryonic stem cells (ESCs) using DNA microarrays. We identified several genes with much greater signal in undifferentiated ESCs than in their differentiated derivatives, among them the putative stemness gene encoding junctional adhesion molecule B (Jam-B gene). However, in spite of the specific expression in undifferentiated ESCs, Jam-B mutant ESCs had normal morphology and pluripotency. Furthermore, Jam-B homozygous mutant mice are fertile and have no overt developmental defects. Moreover, we found that neural and hematopoietic stem cells recovered from Jam-B mutant mice are not impaired in their ability to self-renew and differentiate. These results demonstrate that Jam-B is dispensable for normal mouse development and stem cell identity in embryonic, neural, and hematopoietic stem cells.     

Development of an HPLC Method with an ODS Column to Determine Low Levels of Aspartame Diastereomers in Aspartame

α-L-Aspartyl-D-phenylalanine methyl ester (L, D-APM) and α-D-aspartyl-L-phenylalanine methyl ester (D, L-APM) are diastereomers of aspartame (N-L-α-Aspartyl-L-phenylalanine-1-methyl ester, L, L-APM). The Joint FAO/WHO Expert Committee on Food Additives has set 0.04 wt% as the maximum permitted level of the sum of L, D-APM and D, L-APM in commercially available L, L-APM. In this study, we developed and validated a simple high-performance liquid chromatography (HPLC) method using an ODS column to determine L, D-APM and D, L-APM in L, L-APM. The limits of detection and quantification, respectively, of L, D-APM and D, L-APM were found to be 0.0012 wt% and 0.004 wt%. This method gave excellent accuracy, repeatability, and reproducibility in a recovery test performed on five different days. Moreover, the method was successfully applied to the determination of these diastereomers in commercial L, L-APM samples. Thus, the developed method is a simple, useful, and practical tool for determining L, D-APM and D, L-APM levels in L, L-APM.     

Overexpression of a rice gene encoding a small C2 domain protein OsSMCP1 increases tolerance to abiotic and biotic stresses in transgenic Arabidopsis

Plant growth and crop production are limited by environmental stress. We used a large population of transgenic Arabidopsis expressing rice full-length cDNAs to isolate the rice genes that improve the tolerance of plants to environmental stress. By sowing T2 seeds of the transgenic lines under conditions of salinity stress, the salt-tolerant line R07047 was isolated. It expressed a rice gene, OsSMCP1, which encodes a small protein with a single C2 domain, a Ca²⁺-dependent membrane-targeting domain. Retransformation of wild-type Arabidopsis revealed that OsSMCP1 is responsible for conferring the salt tolerance. It is particularly interesting that R07047 and newly constructed OsSMCP1-overexpressing Arabidopsis showed enhanced tolerance not only to high salinity but also to osmotic, dehydrative, and oxidative stresses. Furthermore, R07047 showed improved resistance to Pseudomonas syringae. The OsSMCP1 expression in rice is constitutive. Particle-bombardment-mediated transient expression analysis revealed that OsSMCP1 is targeted to plastids in rice epidermal cells. It induced overexpression of several nuclear encoded genes, including the stress-associated genes, in transgenic Arabidopsis. No marked morphological change or growth retardation was observed in R07047 or retransformants. For molecular breeding to improve the tolerance of crops against environmental stress, OsSMCP1 is a promising candidate.     

Persistence of Mhc heterozygosity in homozygous clonal killifish,Rivulus marmoratus: implications for the origin of hermaphroditism

The mangrove killifish Rivulus marmoratus, a neotropical fish in the order Cyprinodontiformes, is the only known obligatorily selfing, synchronous hermaphroditic vertebrate. To shed light on its population structure and the origin of hermaphroditism, major histocompatibility complex (Mhc) class I genes of the killifish from seven different localities in Florida, Belize, and the Bahamas were cloned and sequenced. Thirteen loci and their alleles were identified and classified into eight groups. The loci apparently arose approximately 20 million years ago (MYA) by gene duplications from a single common progenitor in the ancestors of R. marmoratus and its closest relatives. Distinct loci were found to be restricted to different populations and different individuals in the same population. Up to 44% of the fish were heterozygotes at Mhc loci, as compared to near homozygosity at non-Mhc loci. Large genetic distances between some of the Mhc alleles revealed the presence of ancestral allelic lineages. Computer simulation designed to explain these findings indicated that selfing is incomplete in R. marmoratus populations, that Mhc allelic lineages must have diverged before the onset of selfing, and that the hermaphroditism arose in a population containing multiple ancestral Mhc lineages. A model is proposed in which hermaphroditism arose stage-wise by mutations, each of which spread through the entire population and was fixed independently in the emerging clones.     

Stereoselective Synthesis of (S,E)-6-Isopropyl-3,9-dimethyl-5,8-decadienyl Acetate,the (S)-Enantiomer of the Yellow Scale Pheromone

The (S)-enantiomer of the sex pheromone of the yellow scale (Aonidiella citrina), (S,E)-6-isopropyl-3,9-dimethyl-5,8-decadienyl acetate, was stereoselectively synthesized from (R)-(+)-citronellic acid.     

Glycine significantly enhances bacterial membrane vesicle production: a powerful approach for isolation of LPS-reduced membrane vesicles of probiotic Escherichia coli

Bacterial membrane vesicles (MVs) have attracted strong interest in recent years as novel nanoparticle delivery platforms. Glycine is known to induce morphological changes in the outer layer of bacteria. We report here that glycine dramatically facilitates MV production in a flagella-deficient mutant of the non-pathogenic probiotic Escherichia coli strain Nissle 1917. Supplementation of culture medium with 1.0% glycine induced cell deformation at the early exponential phase, eventually followed by quasi-lysis during the late exponential to stationary phase. Glycine supplementation also significantly increased the number of MVs with enlarged particle size and altered the protein profile with an increase in the inner membrane and cytoplasmic protein contents as compared to non-induced MVs. Of note, the endotoxin activity of glycine-induced MVs was approximately eightfold or sixfold lower than that of non-induced MVs when compared at equal protein or lipid concentrations respectively. Nevertheless, glycine-induced MVs efficiently induced both immune responses in a mouse macrophage-like cell line and adjuvanticity in an intranasal vaccine mouse model, comparable to those of non-induced MVs. We propose that the present method of inducing MV production with glycine can be used for emerging biotechnological applications of MVs that have immunomodulatory activities, while dramatically reducing the presence of endotoxins.