Induction of the Differentiation of HL-60 Promyelocytic Leukemia Cells by l-Ascorbic Acid

The present study was undertaken to examine the effect of l-ascorbic acid (LAA) on the growth of HL-60 promyelocytic leukemia cells, besides induction of apoptosis. LAA (≥10^-4?M) was found to markedly inhibit the proliferation of HL-60 in liquid culture and clonogenicity in semisolid culture. Moreover, LAA-treated HL-60 showed activity to produce chemiluminescence and expressed CD 66b cell surface antigens, indicating that LAA induces the differentiation of HL-60 mainly into granulocytes. The results are supported by morphological changes of LAA-treated HL-60 into segmented neutrophils. Therefore, the inhibitory effect of LAA on the growth of HL-60 cells seems to arise from the induction of differentiation. To assess the potential role of LAA, cells were exposed to oxygen radical scavengers in the absence or presence of LAA. Catalase abolished and superoxide dismutase promoted LAA-induced differentiation of HL-60. Thus, H²O² produced as a result of LAA treatment seems to play a major role in induction of HL-60 differentiation.     

Cellular defense against heat shock-induced oxidative damage by mitochondrial NADP+-dependent isocitrate dehydrogenase

Heat shock may increase oxidative stress due to increased production of reactive oxygen species and/or the promotion of cellular oxidation events. Mitochondrial NADP⁺-dependent isocitrate dehydrogenase (IDPm) produces NADPH, an essential reducing equivalent for the antioxidant system. The protective role of IDPm against heat shock in HEK293 cells, an embryonic kidney cell line, was investigated in control and cells transfected with the cDNA for IDPm, where IDPm activity was 6–7 fold higher than that in the control cells carrying the vector alone. Upon exposure to heat shock, the viability was lower and the protein oxidation, lipid peroxidation and oxidative DNA damage were higher in control cells as compared to HEK293 cells in which IDPm was over-expressed. We also observed the significant difference in the cellular redox status reflected by the endogenous production of reactive oxygen species, NADPH pool and GSH recycling between two cells. The results suggest that IDPm plays an important role as an antioxidant defense enzyme in cellular defense against heat shock through the removal of reactive oxygen species.     

Enhanced production of biomass and lipids by supplying CO2 in marine microalga Dunaliella sp.

Non-food-based biofuel feedstocks are in high demand worldwide. Among the various feedstocks, microalgae are the most promising feedstock for mitigating atmospheric CO₂ and producing biodiesel. In this study, various concentrations of CO₂, from 0.03 to 12%, were used to investigate their effect on the cell growth, biomass and lipid production and fatty acid composition of Dunaliella sp. in a closed photobioreactor. The results showed that the highest biomass and total lipids, 521 mg/L/d and 40 mg/L/d, respectively, were produced with 5% CO₂ aeration during the logarithmic growth phase. The oleic acid (18:1n9c) and elaidic acid (18:1n9t) contents were increased approximately two fold. The physiological responses of Dunaliella sp. at 10% CO₂ were similar to those at 5% CO₂. Therefore, the present results suggest that 5–10% is a suitable CO₂ concentration range for Dunaliella sp. growth to mitigate atmospheric CO₂ and increase biofuel production.     

Metabolic profiling and enhanced production of phytosterols by elicitation with methyl jasmonate and silver nitrate in whole plant cultures of Lemna paucicostata

In this study, the effects of methyl jasmonate (MJ) and silver nitrate (SN) treatment on metabolic profiles and yields of phytosterols such as campesterol, stigmasterol, and β-sitosterol in whole plant cultures of Lemna paucicostata were investigated using gas chromatography–mass spectrometry coupled with multivariate statistical analysis. The MJ and SN treatments retarded the growth of L. paucicostata plants, while they enhanced the yields of three phytosterols, compared to control. Higher yields of phytosterols were attained at day 28 compared to day 42. Moreover, stigmasterol yield was the highest at 0.85 mg/g from day 28 plants grown under MJ + SN co-treated culture. Among the various metabolites, the levels of palmitic and stearic acids, which might participate in a defense mechanism, were higher in the MJ + SN condition than in control. To determine the optimal timing of MJ + SN addition, MJ + SN was added on days 21, 28, and 35 after inoculation. The total yield and productivity of phytosterol reached maximum levels when the MJ + SN was added at day 35. The highest productivity of stigmasterol (6.08 mg/L) was also achieved when MJ + SN was added on day 35.     

Proteomic analysis of kidneys from selenoprotein M transgenic rats in response to increased bioability of selenium

Background

To characterize changes in global protein expression in kidneys of transgenic rats overexpressing human selenoprotein M (SelM) in response to increased bioabivility of selenium (Sel), total proteins extracted from kidneys of 10-week-old CMV/hSelM Tg and wild-type rats were separated by 2-dimensional gel electrophoresis and measured for changes in expression.

Results

Ten and three proteins showing high antioxidant enzymatic activity were up- and down-regulated, respectively, in SelM-overexpressing CMV/hSelM Tg rats compared to controls based on an arbitrary 2-fold difference. Up-regulated proteins included LAP3, BAIAP2L1, CRP2, CD73 antigen, PDGF D, KIAA143 homolog, PRPPS-AP2, ZFP313, HSP-60, and N-WASP, whereas down-regulated proteins included ALKDH3, rMCP-3, and STC-1. After Sel treatment, five of the up-regulated proteins were significantly increased in expression in wild-type rats, whereas there were no changes in CMV/hSelM Tg rats. Only two of the down-regulated proteins showed reduced expression in wild-type and Tg rats after Sel treatment.

Conclusions

These results show the primary novel biological evidences that new functional protein groups and individual proteins in kidneys of Tg rats relate to Sel biology including the response to Sel treatment and SelM expression.     

Direct Detection of Disease-Associated Prions in Brain and Lymphoid Tissue Using Antibodies Recognizing the Extreme N-terminus of PrPC

A simple diagnostic test is described for the detection of TSE in bovine, ovine and human brain and lymphoid tissue that obviates the use of proteinase K as a discriminating reagent. The immunoassay utilises high affinity anti-peptide antibodies that appear blind to the normal isoform of prion protein (PrP^C). These reagents have been produced with novel N-terminal chimeric peptides and we hypothesise that the retention and stability of the extreme N-terminus of PrP in the disease-associated aggregate makes it an operationally specific marker for TSE. Accordingly, the assay involves homogenisation of the tissue directly in 8M guanidine hydrochloride, a simple one-step capture of PrP^Sc followed by detection with a europium-labelled anti-PrP^C antibody. This rapid assay clearly differentiates between levels of disease-associated PrP extracted from brain and lymphoid tissues taken from confirmed TSE positive and negative cattle and sheep. The assay can also be used to detect PrP^Sc in cases of vCJD.     

Peripheral Afferent Mechanisms Underlying Acupuncture Inhibition of Cocaine Behavioral Effects in Rats

Administration of cocaine increases locomotor activity by enhancing dopamine transmission. To explore the peripheral mechanisms underlying acupuncture treatment for drug addiction, we developed a novel mechanical acupuncture instrument (MAI) for objective mechanical stimulation. The aim of this study was to evaluate whether acupuncture inhibition of cocaine-induced locomotor activity is mediated through specific peripheral nerves, the afferents from superficial or deep tissues, or specific groups of nerve fibers. Mechanical stimulation of acupuncture point HT7 with MAI suppressed cocaine-induced locomotor activity in a stimulus time-dependent manner, which was blocked by severing the ulnar nerve or by local anesthesia. Suppression of cocaine-induced locomotor activity was elicited after HT7 stimulation at frequencies of either 50 (for Meissner corpuscles) or 200 (for Pacinian corpuscles) Hz and was not affected by block of C/Aδ-fibers in the ulnar nerve with resiniferatoxin, nor generated by direct stimulation of C/Aδ-fiber afferents with capsaicin. These findings suggest that HT7 inhibition of cocaine-induced locomotor activity is mediated by A-fiber activation of ulnar nerve that originates in superficial and deep tissue.     

A Novel High‐Energy Hybrid Supercapacitor with an Anatase TiO2–Reduced Graphene Oxide Anode and an Activated Carbon Cathode

A hybrid supercapacitor with high energy and power densities is reported. It comprises a composite anode of anatase TiO₂ and reduced graphene oxide and an activated carbon cathode in a non‐aqueous electrolyte. While intercalation compounds can provide high energy typically at the expense of power, the anatase TiO₂ nanoparticles are able to sustain both high energy and power in the hybrid supercapacitor. At a voltage range from 1.0 to 3.0 V, 42 W h kg^?1 of energy is achieved at 800 W kg^?1. Even at a 4‐s charge/discharge rate, an energy density as high as 8.9 W h kg^?1 can be retained. The high energy and power of this hybrid supercapacitor bridges the gap between conventional batteries with high energy and low power and supercapacitors with high power and low energy.