SU-8-carbon composite as conductive photoresist for biochip applications

A composite photoresist has been developed for the direct photopatterning of electrodes useful as biochip substrates. The material is composed of SU-8 polymer added with graphite carbon filler which enables patterning of conductive thin films (22μm) on both glass substrate and transparency flexible film with a standard UV photolithography protocol. The resolution obtained using the conductive composite compared well with the bare resist, with lateral resolutions of 5 and 10μm for bare and conductive resists, respectively. The obtained electrodes, after an electrochemical pre-treatment, exhibited very good electrochemical behaviors, opening the path to various electrochemical detections and grafting possibilities. In order to demonstrate the potentialities of the developed material in the biosensors and biochips field, DNA probes were electrografted, using diazonium chemistry, directly at the composite photoresist surface. Target oligonucleotide interactions were detected using chemiluminescent labeling and a satisfactory detection limit of 0.25nM target sequence was demonstrated with a detection ranging over three orders of magnitude.     

Microbial transformation of deoxyandrographolide and their inhibitory activity on LPS-induced NO production in RAW 264.7 macrophages

A series of analogues of deoxyandrographolide (1) transformed by Cunninghamella blakesleana AS 3.2004 were isolated and identified by spectral methods including 2D NMR. Among them, 3-oxo-17,19-dihydroxy-7,13-ent-labdadien-15,16-olide (9), 3-oxo-19-hydroxy-1,13-ent-labdadien-15,16-olide (16), 3-oxo-1β-hydroxy-14-deoxy-andrographolide (17) and 3-oxo-2β-hydroxy-14-deoxyandrographolide (18) are new compounds. And their structure-activity relationships (SAR) of inhibitory activity on LPS-induced NO production in RAW 264.7 macrophage cells were also discussed.     

塔里木裂腹鱼群体遗传结构及遗传多样性分析

塔里木裂腹鱼为塔里木河水系特有濒危裂腹鱼类。研究采集5个群体(多浪渠首、喀拉喀什河、木扎提河、塔什库尔干、玉龙喀什河)塔里木裂腹鱼,扩增线粒体控制区第一高变区,共获得长度456 bp序列95条。塔里木裂腹鱼单倍型多样度和核苷酸多样度分别为0.7118、0.0024。AMOVA分析显示,群体间遗传分化显著。FST值统计检验表明,除喀拉喀什河群体与玉龙喀什河群体之间差异不显著外,其他两两群体之间都是显著的。分子系统树和单倍型网络图分析表明,塔里木裂腹鱼单倍型间关系较近。中性检验和mismatch分析显示,塔里木裂腹鱼群体经历过近期群体扩张事件。根据核苷酸不配对分布τ值计算其群体扩张时间为20万年前。天山、昆仑山的运动以及第四纪冰期-间冰期的变化可能影响了塔里木裂腹鱼的群体历史动态。     

Synthesis,evaluation of anti-HIV-1 and anti-HCV activity of novel 2′,3′-dideoxy-2′,2′-difluoro-4′-azanucleosides

A series of 2′,3′-dideoxy-2′,2′-difluoro-4′-azanucleosides of both pyrimidine and purine nucleobases were synthesized in an efficient manner starting from commercially available L-pyroglutamic acid via glycosylation of difluorinated pyrrolidine derivative 15. Several 4′-azanucleosides were prepared as a separable mixture of α- and β-anomers. The 6-chloropurine analogue was obtained as a mixture of N⁷ and N⁹ regioisomers and their structures were identified based on NOESY and HMBC spectral data. Among the 4′-azanucleosides tested as HIV-1 inhibitors in primary human lymphocytes, four compounds showed modest activity and the 5-fluorouracil analogue (18d) was found to be the most active compound (EC₅₀ = 36.9 μM) in this series. None of the compounds synthesized in this study demonstrated anti-HCV activity.     

Effect of species, root branching order and season on the root traits of 13 perennial grass species

Aims

Inter-specific comparisons of plant traits may vary depending on intra-specific variation. Here we examine the impact of root branching order and season on key functional root traits for grass species. We also compare root traits among co-existing grass species as a step towards defining root trait syndromes.

Methods

Monocultures of 13 grass species, grown under field conditions and subjected to intensive management, were used to record root trait values for coarse roots (1st order, >0.3?mm), fine roots (2nd and 3rd orders, <0.2?mm) and mixed root samples over three growing seasons.

Results

Branching order and species had a significant effect on root trait values, whereas season showed a marginal effect. The diameter of coarse roots was more variable than that of fine roots and, as expected, coarse roots had higher tissue density and lower specific root length values than fine roots. Principal component analysis run on eight root traits provided evidence for two trait syndromes related to resource acquisition and conservation strategies across grass species.

Conclusions

Our data show that root branching order is the main determinant of root trait variation among species. This highlights the necessity to include the proportion of fine vs coarse roots when measuring traits of mixed root samples.     

Effects of treatment with coenzyme Q10 on exercised rat aorta

In this study, the effect of long-term supplementation of coenzyme Q10 (CoQ10) on the responses of swim-trained rat aorta was investigated. Twenty-four adult male Wistar rats were divided into four groups: untrained, trained, untrained+CoQ10, and trained+CoQ10 group. In the trained groups rats swam for 60 min/day, five days/week for six weeks. The CoQ10 supplements were administered by intraperitoneal injection at a daily dose of 10 mg·kg-1 of body weight five days/week for six weeks. Swimming of the rats was performed in a container containing tap water. Rats were sacrificed and thoracic aortas were removed for ex vivo analysis after the last swimming session. The aortas were cut into rings 2.5 mm in length. Concentration-response curves for phenylephrine (PHE, 10-9-3×10-4 M) and potassium chloride (KCl, 5-100 mM) were isometrically recorded. The sensitivity and maximal responses to PHE and KCl of aortic rings obtained from trained rats were lower than those of untrained rats. CoQ10 supplementation decreased the responses to both vasoconstrictors in untrained and especially in trained groups. Although neither CoQ10 nor training did affect malondialdehyde (MDA) and protein carbonyl (PC) levels, creatine kinase (CK) activity decreased and superoxide dismutase (SOD) activity increased only with exercise training. Glutathione (GSH) levels increased in CoQ10 supplemented-untrained rats. In conclusion, our results suggest that CoQ10 supplementation may have beneficial effects during exercise.     

Physiological heterogeneity of Pseudomonas taetrolens during lactobionic acid production

Physiological heterogeneity constitutes a critical parameter in biotechnological systems since both metabolite yield and productivity are often hampered by the presence of undesired physiological cell subpopulations. In the present study, the physiological status and functionality of Pseudomonas taetrolens cells were monitored by multiparameter flow cytometry during fermentative lactobionic acid production at the shake-flask and bioreactor scale. In shake-flask fermentation, the onset of the lactobionic acid production phase was accompanied by a progressive loss of cellular metabolic activity, membrane polarization, and membrane integrity concomitantly to acidification. In fact, population dynamics has shown the prevalence of damaged and dead subpopulations when submitted to a pH?<?4 from 16?h onwards. Furthermore, fluorescence-activated cell sorting revealed that these sublethally injured cells were nonculturable. In contrast, P. taetrolens cells exhibited a robust physiological status during bioreactor cultivations performed with a pH-shifted strategy at 6.5, remaining predominantly healthy and metabolically active (>96?%) as well as maintaining bioconversion efficiency throughout the course of the fermentation. Additionally, an assessment of the seed culture’s physiological robustness was carried out in order to determine the best seed culture age. Results showed that bioreactor culture performance, growth, and lactobionic acid production efficiency were strongly dependent on the physiological heterogeneity displayed by the seed culture. This study provides the most suitable criteria for optimizing lactobionic acid production efficiency through a novel flow cytometric-based approach based on the physiological status of P. taetrolens. It also constitutes a valuable, broad-ranging methodology for the enhancement of microbial bioprocesses involved in the production of secondary metabolites.     

Sweet-taste-suppressing compounds: current knowledge and perspectives of application

Sweet-tasting compounds are recognized by a heterodimeric receptor composed of the taste receptor, type 1, members 2 (T1R2) and 3 (T1R3) located in the mouth. This receptor is also expressed in the gut where it is involved in intestinal absorption, metabolic regulation, and glucose homeostasis. These metabolic functions make the sweet taste receptor a potential novel therapeutic target for the treatment of obesity and related metabolic dysfunctions such as diabetes. Existing sweet taste inhibitors or blockers that are still in development would constitute promising therapeutic agents. In this review, we will summarize the current knowledge of sweet taste inhibitors, including a sweet-taste-suppressing protein named gurmarin, which is only active on rodent sweet taste receptors but not on that of humans. In addition, their potential applications as therapeutic tools are discussed.     

Current state of the development of mesenchymal stem cells into clinically applicable Schwann cell transplants

Schwann cells are critically important in recovery from injuries to the peripheral nervous system, and their absence from the central nervous system (CNS) may be a critical limiting factor in the CNS regeneration capacity. Various types of stem cells have been investigated for their potential to be induced to develop a Schwann cell phenotype, with mesenchymal stem cells (MSCs) being the most promising among them. The methods for inducing MSCs differentiation into Schwann cell-like cells are presented in detail in this review. The evidence related to successful differentiation of MSCs to Schwann cell-like cells is particularly discussed herein, which includes the changes in morphology, phenotype, function, and proteome. The possible explanations for the differentiation of MSCs to Schwann cell-like cells are also presented. Finally, we suggest future research aims which will need to be fulfilled to elucidate the biology of Schwann cell differentiation and MSC transdifferentiation, to enable clinical application of therapeutic differentiated MSC transplantation into nerve injury sites.