Light Funneling Profile During Enhanced Transmission Through a Subwavelength Metallic Slit

Plasmonics - The funneling profile of enhanced light transmission through a subwavelength slit in a perfect electric conductor is studied with finite-difference time-domain simulation. From the...     

Biological characteristics of foam cell formation in smooth muscle cells derived from bone marrow stem cells

Bone marrow mesenchymal stem cells (BMSC) can differentiate into diverse cell types, including adipogenic, osteogenic, chondrogenic and myogenic lineages. There are lots of BMSC accumulated in atherosclerosis vessels and differentiate into VSMC. However, it is unclear whether VSMC originated from BMSC (BMSC-SMC) could remodel the vessel in new tunica intima or promote the pathogenesis of atherosclerosis. In this study, BMSC were differentiated into VSMC in response to the transforming growth factor β (TGF-β) and shown to express a number of VSMC markers, such as α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain1 (SM-MHC1). BMSC-SMC became foam cells after treatment with 80 mg/L ox-LDL for 72 hours. Ox-LDL could upregulate scavenger receptor class A (SR-A) but downregulate the ATP-binding cassette transporter A1 (ABCA1) and caveolin-1 protein expression, suggesting that modulating relative protein activity contributes to smooth muscle foam cell formation in BMSC-SMC. Furthermore, we found that BMSC-SMC have some biological characteristics that are similar to VSMC, such as the ability of proliferation and secretion of extracellular matrix, but, at the same time, retain some biological characteristics of BMSC, such as a high level of migration. These results suggest that BMSC-SMC could be induced to foam cells and be involved in the development of atherosclerosis.     

Antifibrotic effect of the Chinese herbs, Astragalus mongholicus and Angelica sinensis, in a rat model of chronic puromycin aminonucleoside nephrosis

Nephrotic syndrome has long been treated in China with two herbs, Astragalus mongholicus and Angelica sinensis, which may have antifibrotic effects. METHODS: Rats with chronic puromycin-induced nephrosis were treated with Astragalus and Angelica 3 mL/d (n = 7) or enalapril 10 mg/kg/d (n = 7). Normal control rats (n = 7) received saline rather than puromycin, and an untreated control group (n = 7) received puromycin but no treatment. After 12 weeks, stained sections of the glomerulus and tubulointerstitium were evaluated for injury. Immunohistochemistry staining measured extracellular matrix components, transforming growth factor-beta1 (TGFbeta1), osteopontin, ED-1-positive cells, and alpha-actin. TGFbeta1 mRNA was assessed by in situ hybridization. Renin, ACE activity, angiotensin, and aldosterone were measured by radioimmunoassay or colorimetry. In the untreated rats, chronic renal injury progressed to marked fibrosis at 12 weeks. Astragalus and Angelica significantly reduced deterioration of renal function and histologic damage. Expressions of type III and IV collagen, fibronectin, and laminin also decreased significantly. This anti-fibrotic effect was similar to that of enalapril. The herbs had no effect on the renin-angiotensin system but did reduce the number of ED-1-positive, and alpha-actin positive cells and expression of osteopontin compared to untreated controls. The combination of Astragalus and Angelica retarded the progression of renal fibrosis and deterioration of renal function with comparable effects of enalapril. These effects were not caused by blocking the intrarenal renin-angiotensin system, but associated with suppression of the overexpression of TGFbeta1 and osteopontin, reduction of infiltrating macrophages, and less activation of renal intrinsic cells [corrected].     

Cold and carbon dioxide used as multi-hurdle preservation do not induce appearance of viable but non-culturable Listeria monocytogenes

AIMS: To study whether the exposure to cold (4 degrees C) and carbon dioxide which results in the elongation of Listeria cells, induces a viable but nonculturable (VBNC) state. METHODS AND RESULTS: When cold and CO2 stressed L. monocytogenes were observed under a fluorescence microscope, using the LIVE/DEAD BacLight bacteria viability kit (Molecular Probes, Eugene, OR, USA), the healthy, mildly injured, and the putative VBNC cells accounted for 31.0% of the stressed cell population. By using the selective plate count, 31.4% of the same stressed cell population was found to be healthy and mildly injured (putative VBNC cells not included). If there were VBNC state cells present, we should have observed a significant difference between the above two numbers. In fact, there was no significant difference between the results obtained from those two methods. CONCLUSIONS: There were no VBNC state cells observed in the stressed cell population. We conclude that cold and CO2 do not induce L. monocytogenes to enter a VBNC state. SIGNIFICANCE AND IMPACT OF THE STUDY: Cold and modified atmospheres are widely used in fresh muscle food and fruit preservation. Whether they would induce L. monocytogenes into a VBNC state is of a great concern for microbial food safety.     

松科的核型和系统发育研究

松科通常主要依据长、短枝及叶等的形态特征分成冷杉亚科、落叶松亚科和松亚科。该科各属的核型可以划分成5个类型：(1)松型(24(22)m+0(2)sm);(2)冷杉型((22～14)m十(2～l0)sm(st));(3)落叶松型(12m+12sm(st));(4)花旗松型(10m+12sm+4t);(5)金钱松型(4sm+40t(4SC))。本文根据核型资料的比较分析,各属从原始到进化的顺序可能是：松属(松型核型)-银杉属、云杉属、铁杉属、(雪松属)、油杉属、冷杉属(冷杉型核型)→黄杉属、落叶松属(花旗松型核型和落叶松型核型)→金钱松属(金钱松型核型)。这个顺序和亲缘关系在以核型的平均臂比为纵坐标、染色体长度比为横坐标的坐标图上得到清楚反映(不包括金钱松属)。核型为K(2n)＝44＝4sm+40t(4SC)的单型属金钱松属不仅在染色体数目和核型上与其他各属差异明显,而且具有独特的习性和-系列形态学和解剖学的特征,如落叶乔木(仅同落叶松属),短枝之叶簇状密生而辐射平展呈圆盘状,叶枕在落叶后密集成环节状,雄球花多数簇生短枝顶端,种鳞卵状披针形,成熟时与基部贴生的苞鳞连同崩解的球果中轴一起脱落,叶中3个树脂道及其分布,维管束帽缺如以及传输组织铁杉型(仅同铁杉属)等。因此,本文将金钱松属提升为一个新亚科Pseudolaricoideae L.C．Li,并把原来的3个亚科降为相应的族而隶于松亚科。松科里唯一具K(2n)=24＝12m+12sm(st)核型的黄杉属和落叶松属组成落叶松族,而雪松属按其核型与冷杉族更相近而置于该族。本文根据核型资料建立的松科新系统也得到形态、解剖、植化、免疫、生化、胚胎及占植物等学科有关资料的支持。本文还讨论了前人的松科演化系统。     

Examination of the quality of various force fields and solvation models for the equilibrium simulations of GA88 and GB88

Elucidating the relationship between sequence and conformation is essential for the understanding of functions of proteins. While sharing 88 % sequence identity and differing by only seven residues, GA88 and GB88 have completely different structures and serve as ideal systems for investigating the relationship between sequence and function. Benefiting from the continuous advancement of the computational ability of modern computers, molecular dynamics (MD) simulation is now playing an increasingly important role in the study of proteins. However, the reliability of MD simulations is limited by the accuracy of the force fields and solvent model approximations. In this work, several AMBER force fields (AMBER03, AMBER99SB, AMBER12SB, AMBER14SB, AMBER96) and solvent models (TIP3P, IGB5, IGB7, IGB8) have been employed in the simulations of GA88 and GB88. The statistical results from 19 simulations show that GA88 and GB88 both adopt more compact structures than the native structures. GB88 is more stable than GA88 regardless of the force fields and solvent models utilized. Most of the simulations overestimated the salt bridge interaction. The combination of AMBER14SB force field and IGB8 solvent model shows the best overall performance in the simulations of both GA88 and GB88. AMBER03 and AMBER12SB also yield reasonable results but only in the TIP3P explicit solvent model.     

Cytisine attenuates bone loss of ovariectomy mouse by preventing RANKL‐induced osteoclastogenesis

Postmenopausal Osteoporosis (PMOP) is oestrogen withdrawal characterized of much production and activation by osteoclast in the elderly female. Cytisine is a quinolizidine alkaloid that comes from seeds or other plants of the Leguminosae (Fabaceae) family. Cytisine has been shown several potential pharmacological functions. However, its effects on PMOP remain unknown. This study designed to explore whether Cytisine is able to suppress RANKL‐induced osteoclastogenesis and prevent the bone loss induced by oestrogen deficiency in ovariectomized (OVX) mice. In this study, we investigated the effect of Cytisine on RAW 264.7 cells and bone marrow monocytes (BMMs) derived osteoclast culture system in vitro and observed the effect of Cytisine on ovariectomized (OVX) mice model to imitate postmenopausal osteoporosis in vivo. We found that Cytisine inhibited F‐actin ring formation and tartrate‐resistant acid phosphatase (TRAP) staining in dose‐dependent ways, as well as bone resorption by pit formation assays. For molecular mechanism, Cytisine suppressed RANK‐related trigger RANKL by phosphorylation JNK/ERK/p38‐MAPK, IκBα/p65‐NF‐κB, and PI3K/AKT axis and significantly inhibited these signalling pathways. However, the suppression of PI3K‐AKT‐NFATc1 axis was rescued by AKT activator SC79. Meanwhile, Cytisine inhibited RANKL‐induced RANK‐TRAF6 association and RANKL‐related gene and protein markers such as NFATc1, Cathepsin K, MMP‐9 and TRAP. Our study indicated that Cytisine could suppress bone loss in OVX mouse through inhibited osteoclastogenesis. All data provide the evidence that Cytisine may be a promising agent in the treatment of osteoclast‐related diseases such as osteoporosis.