miR-21 targets the tumor suppressor RhoB and regulates proliferation, invasion and apoptosis in colorectal cancer cells

It has become increasingly clear that microRNAs play an important role in many human diseases including cancer. Here, we show that expression of miR-21 in HEK293 and several colorectal cancer cells was found inversely correlated with ras homolog gene family, member B (RhoB) expression. miR-21 expression significantly suppressed RhoB 3' UTR luciferase-reporter activity, but the inhibitory effect was lost when the putative target sites were mutated. Exogenous miR-21 over-expression mimicked the effect of RhoB knockdown in promoting proliferation and invasion and inhibiting apoptosis, whereas anti-miR-21 or RhoB expression yielded opposite effects, in colorectal cancer cells. These results suggest that miR-21 is a regulator of RhoB expression and RhoB could be a useful target in exploring the potential therapeutic benefits of miR-21 mediated tumor cell behaviors in colorectal cancer.     

Lipin-1γ isoform is a novel lipid droplet-associated protein highly expressed in the brain

Lipin-1 proteins are phosphatidic acid phosphatases (PAPs) catalyzing the conversion from phosphatidic acid (PA) to diacylglycerol (DG). Two alternative splicing isoforms, lipin-1α and -1β, are localized at different subcellular compartments. A third splicing isoform, lipin-1γ was recently cloned and its subcellular localization is unknown. Here, we demonstrate that lipin-1γ is localized to lipid droplets (LDs), an association mediated by a hydrophobic, lipin-1γ-specific domain. Additional expression of lipin-1γ altered LD morphology without affecting the triacylglycerol (TG) level. In human tissues, lipin-1γ is the main lipin-1 isoform expressed in normal human brain, suggesting a specialized role in regulating brain lipid metabolism.     

Two non-vesicular ATP release pathways in the mouse erythrocyte membrane

Erythrocytes are exceptionally suited for analysis of non-exocytotic release mechanisms of ATP, because these cells under physiological conditions lack vesicles. Previous studies have indicated, that Pannexin1 (Panx1) provides a key ATP permeation pathway in many cell types, including human and frog erythrocytes. Here we show that erythrocytes of Panx1(-/-) mice lend further support to this conclusion. However, ATP release, although attenuated, was still observed in Panx1(-/-) mouse erythrocytes. In contrast to Panx1(+/+) cells, this release was not correlated with uptake of extracellularly applied dyes, was insensitive to Panx1 channel blockers, and was inhibited by dipyridamole and stimulated by iloprost. Thus, in erythrocytes, two independent pathways mediate the release of ATP. We also show that glyburide is a strong inhibitor of Panx1 channels.     

Plant growth and nutrient removal in constructed monoculture and mixed wetlands related to stubble attributes

The aim of this study is to test the hypothesis that it depends on plant species used in the wetlands and their stubble growth attributes, as to whether monoculture or mixed wetland is superior in plant growth and nutrient removal. Monoculture and mixed wetland microcosms of five wetland plant species were studied. Significant differences in growth and aboveground biomass were found in the monoculture wetlands. Species that showed faster growth and larger biomass in monoculture wetland were also dominant in the mixed wetland. The mixed wetland exhibited similar biomass and root growth to the averages of five monocultures. ANOVA showed that there were very significant differences among the wetlands in removal rates of all the nutrients studied except nitrate nitrogen (NO₃-N) and chemical oxygen demand (COD). The removal rates from the mixed wetland were generally comparable to the highest removal rates from the monocultures. The species exhibited different stubble growth attributes, with some species showing increasing stubble growth and removal rates, while other species showing decreasing stubble growth and removal rates. The results indicated that in both monocultures and mixed constructed wetlands, growth and nutrient removal rates depended on plant species, and attributes of plant stubble growth affected overall growth and nutrient removal capabilities.     

Whole genome sequence of an unusual Borrelia burgdorferi sensu lato isolate

Human Lyme disease is caused by a number of related Borrelia burgdorferi sensu lato species. We report here the complete genome sequence of Borrelia sp. isolate SV1 from Finland. This isolate is to date the closest known relative of B. burgdorferi sensu stricto, but it is sufficiently genetically distinct from that species that it and its close relatives warrant its candidacy for new-species status. We suggest that this isolate should be named "Borrelia finlandensis."     

Whole-genome sequences of two Borrelia afzelii and two Borrelia garinii Lyme disease agent isolates

Human Lyme disease is commonly caused by several species of spirochetes in the Borrelia genus. In Eurasia these species are largely Borrelia afzelii, B. garinii, B. burgdorferi, and B. bavariensis sp. nov. Whole-genome sequencing is an excellent tool for investigating and understanding the influence of bacterial diversity on the pathogenesis and etiology of Lyme disease. We report here the whole-genome sequences of four isolates from two of the Borrelia species that cause human Lyme disease, B. afzelii isolates ACA-1 and PKo and B. garinii isolates PBr and Far04.     

A homogalacturonan from the radix of Platycodon grandiflorum and the anti-angiogenesis activity of poly-/oligogalacturonic acids derived therefrom

A polysaccharide, PGA4-3b, with an average molecular weight of 8.9 kDa estimated by high-performance gel-permeation chromatography (HPGPC), was isolated from radix of Platycodon grandiflorum (Jacq.) A. DC. Using monosaccharide analysis, methylation analysis and NMR spectroscopy, PGA4-3b was elucidated to be a linear poly-(1→4)-α-d-galactopyranosyluronic acid that contains no methyl ester groups. Partial acid hydrolysis of PGA4-3b yielded a series of poly- or oligogalacturonic acids with different degrees of polymerization (DP), that is, 4-3bde, 4-3bde-O-1, 4-3bde-O-2, 4-3bde-O-3, and 4-3bde-O-4. Cell tube formation inhibition tests with human microvascular endothelial cells (HMEC) for antiangiogenesis analysis showed that 4-3bde-O-1 and 4-3bde-O-2, the fractions with higher molecular weights, could inhibit tube formation, while the native PGA4-3b and low molecular weight fraction 4-3bde-O-3 and 4-3bde-O4 are ineffective. Moreover, 4-3bde-O-2 with DP 5-10 impaired cell tube formation in a dose-dependent way, suggesting its potential to be developed as an anti-angiogenesis drug. This is the first time oligogalacturonic acids are reported to show an anti-angiogenesis effect.