Determination of reducing sugars in the nanomole range with tetrazolium blue

Addition of sodium potassium tartrate to basic solutions of tetrazolium blue [(2,2',5,5'-tetraphenyl-3,3'-dimethoxy 4,4'-biphenylene) ditetrazolium chloride] greatly improved their efficacy as colorimetric reagents for reducing sugar determination. This modification increased sensitivity and decreased reaction time. The modified reagent can determine as little as 1 nmol of neutral sugars as well as 2-amino and N-acetyl amino sugars.     

Eimeria saudiensis N. Sp. (Apicomplexa: Eimeriidae) from the Arabian Oryx (Oryx leucoryx) in Saudi Arabia

Oocysts of Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) are described from the feces of the Arabian oryx, Oryx leucoryx , from the Riyadh Zoo, Saudi Arabia. The oocysts were ellipsoidal or slightly ovoid, 31.2 times 24.5 (24.3–36.5 times 20.0–27.6) μm with a bilayered wall about 1.7 μm thick. The micropyle was covered by a dome-shaped cap. The oocyst residuum was absent, but tiny polar granules were present. The sporocysts were elongate ovoid, 14.3 times 7.2 (11.5–18.5 times 6.0–9.0) μm, had a Stieda body, but lacked a substiedal body. The sporocyst residuum was present, composed of numerous small granules. The sporozoites were elongate club-shaped, and contained two prominent refractile bodies.     

The mouse Wnt-1 gene can act via a paracrine mechanism in transformation of mammary epithelial cells.

The mouse Wnt-1 gene plays an essential role in fetal brain development and can contribute to tumorigenesis when activated aberrantly in the mammary gland. The gene encodes secretory glycoproteins associated with the extracellular or pericellular matrix, and it has been proposed that Wnt-1, as well as its Drosophila homolog wingless, may function in intercellular signalling. We show here that fibroblasts expressing Wnt-1 protein, although not transformed themselves, are able to elicit morphological transformation of neighboring C57MG mammary epithelial cells in coculture experiments. Heparin inhibits this effect, possibly by displacing Wnt-1 protein from its normal site of action. Our results indicate that the Wnt-1 gene can act via a paracrine mechanism in cell culture and strongly support the notion that in vivo the gene may function in cell-to-cell communication.     

丙型肝炎病毒诱发肝细胞癌的分子机制

丙型肝炎是由丙型肝炎病毒(hepatitis C virus,HCV)引起的一种肝脏疾病。肝细胞癌(hepatocellular carcinoma,HCC)是人类最常见的恶性肿瘤之一。大量实验和临床研究表明,HCV的感染是导致肝细胞癌的主要因素之一。尽管目前可以通过直接抗病毒药物治疗HCV感染,但是患肝细胞癌的风险仍然存在。HCV诱发肝细胞癌是一个多步骤过程,其可能是通过病毒因子直接作用和/或通过引起慢性炎症诱发肝癌。因此,需要更好地了解HCV诱发肝细胞癌的分子机制,为肝细胞癌的防治提供研究基础。本文就近年来国内外对丙型肝炎病毒直接作用诱发肝细胞癌的分子机制进行综述,具体从血管生成、细胞凋亡、细胞增殖、上皮 间质转化、脂肪变性和氧化应激6个方面进行阐述,以期更好地了解HCV诱发肝细胞癌的分子机制,为肝细胞癌的防治提供研究基础。     

KVOPO4: A New High Capacity Multielectron Na‐Ion Battery Cathode

Sodium ion batteries have attracted much attention in recent years, due to the higher abundance and lower cost of sodium, as an alternative to lithium ion batteries. However, a major challenge is their lower energy density. In this work, we report a novel multi‐electron cathode material, KVOPO₄, for sodium ion batteries. Due to the unique polyhedral framework, the V³⁺ ? V⁴⁺ ? V⁵⁺ redox couple was for the first time fully activated by sodium ions in a vanadyl phosphate phase. The KVOPO₄ based cathode delivered reversible multiple sodium (i.e. maximum 1.66 Na⁺ per formula unit) storage capability, which leads to a high specific capacity of 235 Ah kg^?1. Combining an average voltage of 2.56 V vs. Na/Na⁺, a high practical energy density of over 600 Wh kg^?1 was achieved, the highest yet reported for any sodium cathode material. The cathode exhibits a very small volume change upon cycling (1.4% for 0.64 sodium and 8.0% for 1.66 sodium ions). Density functional theory (DFT) calculations indicate that the KVOPO₄ framework is a 3D ionic conductor with a reasonably, low Na⁺ migration energy barrier of ≈450 meV, in line with the good rate capability obtained.     

EARLY STARVATION1 specifically affects the phosphorylation action of starch‐related dikinases

Starch phosphorylation by starch‐related dikinases glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD) is a key step in starch degradation. Little information is known about the precise structure of the glucan substrate utilized by the dikinases and about the mechanisms by which these structures may be influenced. A 50‐kDa starch‐binding protein named EARLY STARVATION1 (ESV1) was analyzed regarding its impact on starch phosphorylation. In various in vitro assays, the influences of the recombinant protein ESV1 on the actions of GWD and PWD on the surfaces of native starch granules were analyzed. In addition, we included starches from various sources as well as truncated forms of GWD. ESV1 preferentially binds to highly ordered, α‐glucans, such as starch and crystalline maltodextrins. Furthermore, ESV1 specifically influences the action of GWD and PWD at the starch granule surface. Starch phosphorylation by GWD is decreased in the presence of ESV1, whereas the action of PWD increases in the presence of ESV1. The unique alterations observed in starch phosphorylation by the two dikinases are discussed in regard to altered glucan structures at the starch granule surface.     

Nutrient Leaching and End Product Accumulation in Plastic Composite Supports for L-(+)-Lactic Acid Biofilm Fermentation

Investigations on the leachate bioavailability, leaching rate, and lactic acid accumulation properties of plastic composite supports (PCS) were essential for large-scale or long-term lactic acid fermentation. Leachates from PCS and polypropylene discs (controls) were analyzed by the micro-Kjeldahl method; by absorbances at 260, 275, and 280 nm; and by bioassays with Lactobacillus casei subsp. rhamnosus (ATCC 11443). The amount of leached nitrogen in a 20-ml initial soaking solution had a high correlation with the soaking solution's cell density (r = 0.87) and absorbance at 260 nm (r = 0.95). Leaching rates of various PCS were evaluated by 20 20-ml simulated repeated-batch fermentations (RBF). PCS with only yeast extract as the minor agricultural ingredient had a high leaching rate and leached out 51 to 60% of the total nitrogen during the first RBF. PCS blended with dried bovine albumin, dried bovine erythrocytes, and/or soybean flour had slowed nutrient leaching (20 to 30% of the initial leached nitrogen). Hence, they could still maintain 1 g of lactic acid per liter and measurable cell density (absorbance at 620 nm, 0.4 to 0.6) at the 20th 20-ml RBF. Lactic acid accumulation properties of PCS were evaluated by soaking the supports in a 30% lactic acid solution for 72 h at 45(deg)C. The lactic acid-soaked supports were rinsed three times and then heat treated (121(deg)C, 15 min) in 15 ml of deionized water. The results showed that lactic acid accumulation in PCS was mainly due to absorption and had no correlation with lactic acid production or biofilm formation.