间断低氧对大鼠下丘脑超微结构及前增食欲素水平的影响

目的探讨睡眠中间断低氧对大鼠下丘脑前增食欲素及受体水平的影响以及下丘脑超微结构的变化。方法大鼠分成对照组、间断低氧组和持续低氧组,分别给予吸入空气,持续低氧和间断低氧气体,并在实验开始后1d、3d、1w和4w应用RT-PCR方法测定大鼠下丘脑前增食欲素及受体水平,分析其间的变化关系,电镜观察下丘脑的超微结构变化。结果与对照组和持续低氧组比较,间断低氧4w后大鼠下丘脑前增食欲素mRNA水平明显降低,受体水平升高,但在持续低氧和对照组之间无明显差异。在低氧后1d、3d、7d后大鼠下丘脑前增食欲素mRNA降低,受体水平升高,在4w后,持续低氧组则接近正常。急性持续低氧大鼠超微结构变化更严重,而慢性间断低氧变化更持久。结论慢性间断低氧可以引起下丘脑前增食欲素下降及受体水平升高,急性持续低氧也可引起上述变化,而慢性持续低氧未引起增食欲素改变;慢性间断低氧大鼠下丘脑超微结构表现为严重而持久的变化。     

Diallyl trisulfide induces apoptosis and inhibits proliferation of A549 cells in vitro and in vivo

Lung cancer is the leading cause of cancer-related mortality all over the world. In recent years, pulmonary adenocarcinoma has surpassed squamous cell carcinoma in frequency and is the predominant form of lung cancer in many countries. Epidemiological investigations have shown an inverse relationship between garlic (Allium sativum) consumption and death rate from many cancers. Diallyl trisulfide (DATS) is one of the garlic-derived compounds (also known as: organosulfer compounds, OSC). DATS can induce apoptosis and inhibit the growth of many cancer cell lines. Our study demonstrated that the apoptotic incidents induced by DATS were a mitochondria-dependent caspase cascade through a significant decrease of the anti-apoptotic Bcl-2 that resulted in up-regulation of the ratio of Bax/Bcl-2 and the activity of caspase-3, -8, and -9. Eventually, DATS induced the apoptosis and inhibited the proliferation in a concentration- and time-dependent manner. Furthermore, by establishing an animal model of female BALB/c nude mice with A549 xenografts, we found that oral gavage of DATS significantly retarded growth of A549 xenografts in nude mice without causing weight loss or any other side effects compared with the control group. All the evidence both in vitro and in vivo suggested that DATS could be an ideal anti-cancer drug.     

Nicotiana chloroplast genome

Summary Using the existing restriction map and probes from wheat and pea ct-DNA, seven protein genes have been localized in the chloroplast genome of N. tabacum. On the clock-like map, the location of each gene is indicated by its time zone: the 15.2 kD polypeptide of the cytochrome b/f complex at 315, cytochrome f at 430, LS of RuBPCase at 450, both and subunits of ATP synthase at or near 500, proton-translocating subunit of ATP synthase at 820, subunit of ATP synthase at 840 and the 32 kD protein at 930. The genome organization of Nicotiana chloroplast DNA is similar to spinach.     

Morusin induces apoptosis and suppresses NF-kappaB activity in human colorectal cancer HT-29 cells

Morusin is a pure compound isolated from root bark of Morusaustralis (Moraceae). In this study, we demonstrated that morusin significantly inhibited the growth and clonogenicity of human colorectal cancer HT-29 cells. Apoptosis induced by morusin was characterized by accumulation of cells at the sub-G₁ phase, fragmentation of DNA, and condensation of chromatin. Morusin also inhibited the phosphorylation of IKK-α, IKK-β and IκB-α, increased expression of IκB-α, and suppressed nuclear translocation of NF-κB and its DNA binding activity. Dephosphorylation of NF-κB upstream regulators PI3K, Akt and PDK1 was also displayed. In addition, activation of caspase-8, change of mitochondrial membrane potential, release of cytochrome c and Smac/DIABLO, and activation of caspase-9 and -3 were observed at the early time point. Downregulation in the expression of Ku70 and XIAP was exhibited afterward. Caspase-8 or wide-ranging caspase inhibitor suppressed morusin-induced apoptosis. Therefore, the antitumor mechanism of morusin in HT-29 cells may be via activation of caspases and inhibition of NF-κB.     

Five New Guaiane Sesquiterpenes from the Endophytic Fungus Xylaria sp. YM 311647 of Azadirachta indica

Five new guaiane sesquiterpenes, 1 – 5 , were isolated from the culture broth of the endophytic fungus Xylaria sp. YM 311647, isolated from Azadirachta indica A. Juss . The structures of these compounds were elucidated on the basis of spectroscopic analyses, and their inhibitory activities against five pathogenic fungi were evaluated. All guaiane sesquiterpenes showed moderate or weak antifungal activities in a broth microdilution assay.     

Faster STORM using compressed sensing

In super-resolution microscopy methods based on single-molecule switching, the rate of accumulating single-molecule activation events often limits the time resolution. Here we developed a sparse-signal recovery technique using compressed sensing to analyze images with highly overlapping fluorescent spots. This method allows an activated fluorophore density an order of magnitude higher than what conventional single-molecule fitting methods can handle. Using this method, we demonstrated imaging microtubule dynamics in living cells with a time resolution of 3 s.     

EPR studies on the superoxide-scavenging capacity of the nutraceutical resveratrol

Resveratrol (3,4',5-trihydroxystilbene), a polyphenolic compound found in mulberries, grapes, and red wine, has received considerable attention because of its apparent protective effects against various degenerative diseases due to its potential antioxidant activities. However, direct evidence for the superoxide-scavenging capacity of resveratrol is lacking in literature. In this study, electron paramagnetic resonance spectroscopy in combination with 5-(diethoxyphosphoryl)-5-methylpyrroline-N-oxide (DEPMPO)-spin trapping technique was utilized to determine the ability of resveratrol in scavenging superoxide anions generated from both potassium superoxide and the xanthine oxidase/xanthine system. We have demonstrated here for the first time that the presence of resveratrol resulted in decreased formation of DEPMPO-superoxide adduct (DEPMPO-OOH) in both the potassium superoxide and xanthine oxidase/xanthine systems, indicating that resveratrol could directly scavenge superoxide anions. The inhibition of DEPMPO-OOH in the xanthine oxidase/xanthine system, however, was found to be much potent as compared to that observed in potassium superoxide system. It was further shown that resveratrol could also directly inhibit xanthine oxidase activity as assessed by oxygen consumption and formation of uric acid. Taken together, the dual role of resveratrol in directly scavenging superoxide and inhibiting its generation via xanthine oxidase reported in this study may explain, at least in part, the protective role of this compound against oxidative injury in various disease processes.     

High frequency of plant regeneration from hypocotyl explants of Brassica carinata A. Br.

An efficient tissue culture system for high frequency of plant regeneration from hypocotyl explants of Brassica carinata was developed via manipulation of culture medium and selection of explants. Explants grown on medium containing combinations of 2 mg l^-1 BA and 0.01 mg l^-1 NAA or 4 mg l^-1 kinetin and 0.01 mg l^-1 2,4-D regenerated shoots at 100% frequency. High frequency shoot regeneration occurred only from explants originating from 6 to 7-day-old but not younger or older seedlings. Explants showed higher regeneration capacity at the distal end than the proximal end, and the upper segment was more regenerative than the lower segment of hypocotyl. Regenerants were rooted on half-strength growth regulator-free medium, acclimatized and developed into normal, fertile plants.Abbreviations BA benzyladenine - 2-4-D 2,4-dichlorophenoxyacetic acid - NAA naphthaleneacetic acid - MS Murashige & Skoog