Supplementation with 9-cis β-carotene-rich alga Dunaliella improves hyperglycemia and adipose tissue inflammation in diabetic mice

Several species of the alga Dunaliella contain high levels of β-carotene. Low dietary β-carotene intake is associated with type 2 diabetes. Dunaliella contains high levels of all-trans and 9-cis isomers of β-carotene and is the best known naturally occurring nutritional source of 9-cis β-carotene. Since vitamin A has been suggested to play a role in glucose and lipid metabolism, we aimed to study the effect of Dunaliella supplementation on diabetes in mice. Ten diabetic db/db mice were fed chow diet fortified with 8 % 9-cis-rich Dunaliella powder. Ten db/db and heterozygous db/+ mice each served as controls and were fed chow diet alone. The control db/db mice developed severe hyperglycemia with fasting glucose levels reaching 400 mg dL^?1. Dunaliella significantly inhibited the elevation of plasma glucose (p?=?0.007). The area under the curve of the glucose tolerance test was 24 % lower in Dunaliella-treated mice than in the control db/db mice. Triglyceride elevation was significantly lower in the Dunaliella group than in the db/db group (p?=?0.007). The mRNA levels of several pro-inflammatory genes in adipose tissue, including monocyte chemotactic protein-1, intercellular adhesion molecule, vascular adhesion molecule-1, receptor-associated protein factor 6, and p-selectin, were elevated in the db/db group as compared to the db/+, whereas their levels were significantly lower in the Dunaliella-treated group. These results suggest that 9-cis β-carotene-rich Dunaliella may inhibit diabetes in db/db mice by reducing inflammation in adipose tissue. This study also emphasizes the importance of β-carotene isomers in our diet.     

Optimization of cardiac cell seeding and distribution in 3D porous alginate scaffolds

Cardiac tissue engineering has evolved as a potential therapeutic approach to assist in cardiac regeneration. We have recently shown that tissue-engineered cardiac graft, constructed from cardiomyocytes seeded within an alginate scaffold, is capable of preventing the deterioration in cardiac function after myocardial infarction in rats. The present article addresses cell seeding within porous alginate scaffolds in an attempt to achieve 3D high-density cardiac constructs with a uniform cell distribution. Due to the hydrophilic nature of the alginate scaffold, its >90% porosity and interconnected pore structure, cell seeding onto the scaffold was efficient and short, up to 30 min. Application of a moderate centrifugal force during cell seeding resulted in a uniform cell distribution throughout the alginate scaffolds, consequently enabling the loading of a large number of cells onto the 3D scaffolds. The percent cell yield in the alginate scaffolds ranged between 60-90%, depending on cell density at seeding; it was 90% at seeding densities of up to 1 x 10(8) cells/cm(3) scaffold and decreased to 60% at higher densities. The highly dense cardiac constructs maintained high metabolic activity in culture. Scanning electron microscopy revealed that the cells aggregated within the scaffold pores. Some of the aggregates were contracting spontaneously within the matrix pores. Throughout the culture there was no indication of cardiomyocyte proliferation within the scaffolds, nor was it found in 3D cultures of cardiofibroblasts. This may enable the development of cardiac cocultures, without domination of cardiofibroblasts with time.     

Chromosome catastrophes involve replication mechanisms generating complex genomic rearrangements

Complex genomic rearrangements (CGRs) consisting of two or more breakpoint junctions have been observed in genomic disorders. Recently, a chromosome catastrophe phenomenon termed chromothripsis, in which numerous genomic rearrangements are apparently acquired in one single catastrophic event, was described in multiple cancers. Here, we show that constitutionally acquired CGRs share similarities with cancer chromothripsis. In the 17 CGR cases investigated, we observed localization and multiple copy number changes including deletions, duplications, and/or triplications, as well as extensive translocations and inversions. Genomic rearrangements involved varied in size and complexities; in one case, array comparative genomic hybridization revealed 18 copy number changes. Breakpoint sequencing identified characteristic features, including small templated insertions at breakpoints and microhomology at breakpoint junctions, which have been attributed to replicative processes. The resemblance between CGR and chromothripsis suggests similar mechanistic underpinnings. Such chromosome catastrophic events appear to reflect basic DNA metabolism operative throughout an organism's life cycle.     

Attenuated glomerular arginine transport prevents hyperfiltration and induces HIF-1α in the pregnant uremic rat

Pregnancy worsens renal function in females with chronic renal failure (CRF) through an unknown mechanism. Reduced nitric oxide (NO) generation induces renal injury. Arginine transport by cationic amino acid transporter-1 (CAT-1), which governs endothelial NO generation, is reduced in both renal failure and pregnancy. We hypothesize that attenuated maternal glomerular arginine transport promotes renal damage in CRF pregnant rats. In uremic rats, pregnancy induced a significant decrease in glomerular arginine transport and cGMP generation (a measure of NO production) compared with CRF or pregnancy alone and these effects were prevented by l-arginine. While CAT-1 abundance was unchanged in all experimental groups, protein kinase C (PKC)-α, phosphorylated PKC-α (CAT-1 inhibitor), and phosphorylated CAT-1 were significantly augmented in CRF, pregnant, and pregnant CRF animals; phenomena that were prevented by coadministrating l-arginine. α-Tocopherol (PKC inhibitor) significantly increased arginine transport in both pregnant and CRF pregnant rats, effects that were attenuated by ex vivo incubation of glomeruli with PMA (a PKC stimulant). Renal histology revealed no differences between all experimental groups. Inulin and p-aminohippurate clearances failed to augment and renal cortical expression of hypoxia inducible factor-1α (HIF-1α) significantly increased in CRF pregnant rat, findings that were prevented by arginine. These studies suggest that in CRF rats, pregnancy induces a profound decrease in glomerular arginine transport, through posttranslational regulation of CAT-1 by PKC-α, resulting in attenuated NO generation. These events provoke renal damage manifested by upregulation of renal HIF-1α and loss of the ability to increase glomerular filtration rate during gestation.     

Cloning Rosa hybrid phenylacetaldehyde synthase for the production of 2-phenylethanol in a whole cell Escherichia coli system

2-Phenylethanol (2-PE) is a desirable compound in the food and perfumery industries with a characteristic rose fragrance. Until now, most of the studied biotechnological processes to produce 2-PE were conducted using natural 2-PE-producing yeasts. Only several researches were conducted in other genetically engineered microorganisms that simulated the Ehrlich pathway for the conversion of amino acids to fusel alcohols. Here, a novel metabolic pathway has been designed in Escherichia coli to produce 2-PE, using the Rosa hybrid phenylacetaldehyde synthase (PAAS), a pyridoxal 5′-phosphate (PLP)-dependent enzyme capable of transforming l-phenylalanine (l-phe) into phenylacetaldehyde by decarboxylation and oxidation. To overcome the enzyme insolubility in E. coli, several plasmids and host strains were tested for their expression ability. The desired results were obtained by using the pTYB21 plasmid containing the intein tag from the Saccharomyces cerevisiae VMA1. It was discovered that the intein PAAS activity is temperature-dependent, working well in the range of 25 to 30 °C but losing most of its activity at 37 °C. When external PLP cofactor was added, the cells produced 0.39 g l^-1 2-PE directly from l-phe. In addition, a biotransformation that was based only on internal de novo PLP synthesis produced 0.34 g l^-1 2-PE, thus creating for the first time an E. coli strain that can produce 2-PE from l-phe without the need for exterior cofactor additions.     

Attention samples stimuli rhythmically

Overt exploration or sampling behaviors, such as whisking, sniffing, and saccadic eye movements, are often characterized by a rhythm. In addition, the electrophysiologically recorded theta or alpha phase predicts global detection performance. These two observations raise the intriguing possibility that covert selective attention samples from multiple stimuli rhythmically. To investigate this possibility, we measured change detection performance on two simultaneously presented stimuli, after resetting attention to one of them. After a reset flash at one stimulus location, detection performance fluctuated rhythmically. When the flash was presented in the right visual field, a 4 Hz rhythm was directly visible in the time courses of behavioral performance at both stimulus locations, and the two rhythms were in antiphase. A left visual field flash exerted only partial reset on performance and induced rhythmic fluctuation at higher frequencies (6-10 Hz). These findings show that selective attention samples multiple stimuli rhythmically, and they position spatial attention within the family of exploration behaviors.