Whole‐brain microcirculation detection after ischemic stroke based on swept‐source optical coherence tomography

The occurrence and development of ischemic stroke are closely related to cerebral blood flow. Real‐time monitoring of cerebral perfusion level is very useful for understanding the mechanisms of the disease. A wide field of view (FOV) is conducive to capturing lesions and observing the progression of the disease. In this paper, we attempt to monitor the whole‐brain microcirculation in middle cerebral artery occlusion (MCAO) rats over time using a wide FOV swept‐source OCT (SS‐OCT) system. A constrained image registration algorithm is used to remove motion artifacts that are prone to occur in a wide FOV angiography. During ischemia, cerebral perfusion levels in the left and right hemispheres, as well as in the whole brain were quantified and compared. Changes in the shape and location of blood vessels were also recorded. The results showed that the trend in cerebral perfusion levels of both hemispheres was highly consistent during MCAO, and the position of the blood vessels varied over time. This work will provide new insights of ischemic stroke and is helpful to assess the effectiveness of potential treatment strategies.      

一株假单胞菌(Pseudomonas sp.)L-1菌株γ-丁基甜菜碱羟化酶基因bbh 的克隆、表达及酶学性质

【目的】γ-丁基甜菜碱羟化酶是生物体内合成L-肉碱的关键酶。从假单胞菌(Pseudomonas sp.)L-1中克隆γ-丁基甜菜碱羟化酶基因,实现其在大肠杆菌(Escherichia coli)中的高效表达,并对表达产物进行酶学性质分析,为生物转化生产L-肉碱奠定基础。【方法】通过PCR克隆γ-丁基甜菜碱羟化酶基因,并将其开放阅读框(ORF)克隆至融合表达载体pET-15b;表达产物经His.Bind Resin纯化后对BBH进行酶学性质及三维空间结构分析;并以静止细胞进行L-肉碱的转化。【结果】成功地克隆了一个γ-丁基甜菜碱羟化酶基因bbh(GenBank:JQ250036),并实现了其在E.coli中的高效表达。融合蛋白以同源二聚体的形式存在,单个亚基的分子量约46.5 kDa,最适反应温度为30℃,最适反应pH为7.5。该酶在45℃以下稳定。在pH6.0时该酶有最高的pH稳定性。以表达bbh基因的重组大肠杆菌静止细胞转化L-肉碱,L-肉碱产量可达12.7mmol/L。【结论】Pseudomonas sp.L-1γ-丁基甜菜碱羟化酶与现有报道的bbh基因有较大的差异。由该基因表达的γ-丁基甜菜碱羟化酶能有效地转化γ-丁基甜菜碱生成L-肉碱。本研究不仅丰富了γ-丁基甜菜碱羟化酶基因资源,而且为L-肉碱的生物转化提供了一种新的转化方案。     

Activation of NF-κB in CD8+ dendritic cells Ex Vivo by the γ134.5 null mutant correlates with immunity against herpes simplex virus 1

The γ₁34.5 protein of herpes simplex viruses (HSV) is essential for virulence. Accordingly, an HSV mutant lacking γ₁34.5 is attenuated in vivo. Despite its vaccine potential, the mechanism by which the γ₁34.5 null mutant triggers protective immunity is unknown. In this report we show that vaccination with the γ₁34.5 null mutant protects against lethal challenge from wild-type virus via IκB kinase in dendritic cells (DCs), which sense virus-associated molecular patterns. Unlike mock-treated DCs, DCs primed with the γ₁34.5 null mutant ex vivo mediate resistance to wild-type HSV after adoptive transfer into naïve mice. Furthermore, the γ₁34.5 null mutant activates IκB kinase, which facilitates p65/RelA phosphorylation and nuclear translocation, resulting in DC maturation. While unable to produce infectious virus in DCs, this mutant virus expresses early and late genes. In its abortive infection, the γ₁34.5 null mutant induces protective immunity more effectively in CD8⁺ DCs than in CD8⁻ DCs. This is mirrored by a higher level of interleukin-6 (IL-6) and IL-12 secretion by CD8⁺ DCs than CD8⁻ DCs. Remarkably, inhibition of p65/RelA phosphorylation or nuclear translocation in CD8⁺ DCs disrupts protective immunity. These results suggest that engagement of the γ₁34.5 null mutant with CD8⁺ DCs elicits innate immunity to activate NF-κB, which translates into protective immunity.     

The effects of garlic-derived sulfur compounds on cell proliferation, caspase 3 activity, thiol levels and anaerobic sulfur metabolism in human hepatoblastoma HepG2 cells

The aim of the present studies was to determine whether the mechanism of biological action of garlic-derived sulfur compounds in human hepatoma (HepG2) cells can be dependent on the presence of labile sulfane sulfur in their molecules. We investigated the effect of allyl sulfides from garlic: monosulfide, disulfide and trisulfide on cell proliferation and viability, caspase 3 activity and hydrogen peroxide (H(2)O(2)) production in HepG2 cells. In parallel, we also examined the influence of the previously mentioned compounds on the levels of thiols, glutathione, cysteine and cysteinyl-glycine, and on the level of sulfane sulfur and the activity of its metabolic enzymes: rhodanese, 3-mercaptopyruvate sulfurtransferase and cystathionase. Among the compounds under study, diallyl trisulfide (DATS), a sulfane sulfur-containing compound, showed the highest biological activity in HepG2 cells. This compound increased the H(2)O(2) formation, lowered the thiol level and produced the strongest inhibition of cell proliferation and the greatest induction of caspase 3 activity in HepG2 cells. DATS did not affect the activity of sulfurtransferases and lowered sulfane sulfur level in HepG2 cells. It appears that sulfane sulfur containing DATS can be bioreduced in cancer cells to hydroperthiol that leads to H(2)O(2) generation, thereby influencing transmission of signals regulating cell proliferation and apoptosis.     

Photosynthesis of Cockspur [Echinochloa crus-galli (L.) Beauv.] at Sites of Naturally Elevated CO2 Concentration

High abundance of cockspur (Echinochloa crus-galli) at the geothermal carbon dioxide spring area in Staveinci indicates that this species is able to grow under widely varying CO₂ concentrations. Living cockspur plants can even be found very close to gas-releasing vents where growth is significantly reduced. Plant height correlated well with CO₂ exposure. The ¹³C value of the CO₂ spring air was –3.9 and ¹³C values of high-, medium-, and low-CO₂ plants were –10.14, –10.44, and –11.95 , respectively. Stomatal response directly followed the prevailing CO₂ concentrations, with the highest reduction of stomatal conductance in high CO₂ concentration grown plants. Analysis of the curves relating net photosynthetic rate to intercellular CO₂ concentration (P _N-C_i curves) revealed higher CO₂ compensation concentration in plants growing at higher CO₂ concentration. This indicates adjustment of respiration and photosynthetic carbon assimilation according to the prevailing CO₂ concentrations during germination and growth. There was no difference in other photosynthetic parameters measured.     

Disentangling the roles of history and local selection in shaping clinal variation of allele frequencies and gene expression in Norway spruce (Picea abies)

Understanding the genetic basis of local adaptation is challenging due to the subtle balance among conflicting evolutionary forces that are involved in its establishment and maintenance. One system with which to tease apart these difficulties is clines in adaptive characters. Here we analyzed genetic and phenotypic variation in bud set, a highly heritable and adaptive trait, among 18 populations of Norway spruce (Picea abies), arrayed along a latitudinal gradient ranging from 47°N to 68°N. We confirmed that variation in bud set is strongly clinal, using a subset of five populations. Genotypes for 137 single-nucleotide polymorphisms (SNPs) chosen from 18 candidate genes putatively affecting bud set and 308 control SNPs chosen from 264 random genes were analyzed for patterns of genetic structure and correlation to environment. Population genetic structure was low (F(ST) = 0.05), but latitudinal patterns were apparent among Scandinavian populations. Hence, part of the observed clinal variation should be attributable to population demography. Conditional on patterns of genetic structure, there was enrichment of SNPs within candidate genes for correlations with latitude. Twenty-nine SNPs were also outliers with respect to F(ST). The enrichment for clinal variation at SNPs within candidate genes (i.e., SNPs in PaGI, PaPhyP, PaPhyN, PaPRR7, and PaFTL2) indicated that local selection in the 18 populations, and/or selection in the ancestral populations from which they were recently derived, shaped the observed cline. Validation of these genes using expression studies also revealed that PaFTL2 expression is significantly associated with latitude, thereby confirming the central role played by this gene in the control of phenology in plants.     

Role of capsaicin sensory nerves and EGF in the healing of gastric ulcer in rats

Accumulating evidence indicates that capsaicin sensitive afferent fibers play a pivotal role not only in gastroprotection but also in ulcer healing. Denervation of capsaicin sensitive afferent fibers exerts an adverse action on these effects. However, whether such an action is mediated through a depression on epidermal growth factor (EGF) is undefined. In this study, the effects of denervation of sensory neurons with capsaicin (100 mg/kg, s.c.) on acetic acid-induced chronic gastric ulcers and their relationship with the EGF expression in salivary glands, serum and gastric mucosa were investigated. Capsaicin significantly increased ulcer size, decreased gastric mucosal cell proliferation at the ulcer margin, angiogenesis in the granulation tissue and also gastric mucus content. Ulcer induction by itself dramatically elevated EGF levels in salivary glands and serum on day 1 and 4, and also in the gastric mucosa on day 4. However, capsaicin completely abolished these effects. It is concluded that stimulation of EGF expression in salivary glands and serum may be one of the mechanisms by which capsaicin sensitive nerves contribute to the gastroprotective and ulcer healing actions in the stomach.