Structural integrity is essential for the protective effect of mitochondrial transplantation against UV-induced cell death.

Mitochondrial transplantation (MT) is a new technology developed in recent years, which injects healthy mitochondria directly into damaged tissues or blood vessels to play a therapeutic role. This technology has been studied in many animal models of various diseases including myocardial ischemia, cerebral stroke, liver and lung injury, and even has been successfully used in the treatment of childhood heart disease. MT can quickly improve tissue function within a few minutes after injection. The speed with which MT improves tissue function is frequently questioned, for it is hard to understand how the whole mitochondrion transports to the damaged sites, enters cells and functions within such a short period of time. Are there small molecules of mitochondrial component responsible for the function of MT? To test this hypothesis, we established an ultra-violet (UV)-irradiated HeLa cell model. The results of colony formation, sulforhodamine B (SRB), and Hoechst 33342/PI double staining assay strongly indicated that MT exhibited a significant protective effect against UV irradiation damage. The UV irradiation-induced cell cycle arresting at S phase, apoptosis, mitochondrial membrane potential (MMP) decreasing, and the related apoptosis signaling factors p-IKKα, p-p65, I-κB and the activation of caspase3 were all reversed by MT treatments to some extent. The mechanisms of MT were evaluated through comparing the effect of thermal inactivation, ultrasonic crushing, and repeated freezing and thawing treatments on MT function. These results denied the above hypothesis that mitochondrial component may be responsible for MT, excluded the function of ATP, mtDNA and other small molecules, and indicated that the mitochondria structural integrity is essential. We also evaluated the effect of Ca2+ concentrations (1 and 1.8 mM) on MT, and the results showed no effect was found in this UV-irradiated HeLa cell model. Our data support a potent anti-UV irradiation effect of MT, and that structural integrity of the mitochondria is critical for its function.

How to teach genetic drift.

Genetic drift is one of the four important factors affecting population genetic balance. Because its form of action is not as apparent as mutation, selection, and migration, which are intuitive and easy to understand, there are potential difficulties in understanding and mastering genetic drift. A particularly prominent problem is that the current introduction of genetic drift contents in textbooks is systematically insufficient. They are either even too rough, or completely neglecting the mathematical foundation such as the binomial theorem, resulting in long-term inadequate learning of genetic drift. In this paper, we summarize the five basic attributes of genetic drift, namely inherent, universal, random, non-directional, and regular features. Based on the concept that the genetic basis of genetic drift is the free combination of male and female gametes, we pointed out that the attribute of random sampling error is the inherent essential feature of genetic drift. Then step by step, from an extremely small population consisting of only one individual (N = 1), we deduced that the effect of genetic drift decreased while population size increased. Through introducing the mathematical model of the binomial theorem, the characteristics of the binomial distribution, and the results of computer simulations, the effect of genetic drift is visually and intuitively displayed to help the teaching the concept of genetic drift.

An acute lytic cell death induced by xanthohumol obstructed ROS detecting in HL-60 cells.

Serum is an important component in cell culture medium. It also possesses potent antioxidant properties. Therefore, the conventional protocols for detecting reactive oxygen species (ROS) in cultured cells with fluorescent probes include washing and suspending cells with serum-free buffers, such as PBS. This transient serum deprivation is essential for the ROS detecting. Unfortunately, it may also cause unexpected results, which push us to choose more optimal experiment conditions. In the present study, we found an acute lytic cell death induced by xanthohumol (XN), which obstructed ROS detecting in human leukemia cell line HL-60 cells. XN induced ROS burst, caused cell swelling, membrane permeability increase, LDH release, and ultimately an acute lytic cell death and cell rupture. These effects could be alleviated by the antioxidant N-Acetyl-L-cysteine (NAC). Apoptosis, pyroptosis or necroptosis were not observed in this process. Results also indicated that 2% serum addition had already completely scavenged ROS induced by 10 µM XN. Taken together, it is strongly suggested to detecting ROS in a serum-free medium when studying where and how ROS generated in cells. The concentration at the ROS maximum point (10 µM XN in this study) can be selected as the optimal concentration.

[How to deduce the seven basic class asci of ordered tetrads in Neurospora].

Genetic analysis is an important part of undergraduate genetics teaching and tetrad analysis is unique and integral for genetic analysis of fungi. The ordered tetrad in Neurospora is an important material for genetic analysis, which can not only be used to study recombination between genes and centromeres, but also between genes themselves, as well as study the fine cross patterns between non-sister chromatids of homologous chromosomes. However, in textbooks and related professional journals, there is a lack of specific introduction to the induction methods of the seven basic class asci used in two genes analysis. In the present paper, we designed a table presenting the correlation between the three tetrad types (PD, NPD, T) and the four segregation pattern groups (Ⅰ Ⅰ, Ⅱ Ⅱ, Ⅰ Ⅱ, Ⅱ Ⅰ) to visually show the 12 possible combinations (3×4=12). Then five of them were excluded through the "×" symbol and in addition with three comments attached with the table, thus finally we obtained seven basic ascus types. We hope that this analytical method can assist the teaching of ordered tetrad analysis in Neurospora.

Isolation, Structure Elucidition, and Immunosuppressive Activity of Diterpenoids from Ligularia fischeri.

Six new (1-3 and 6-8) and seven known diterpenoids were isolated from the whole plant of Ligularia fischeri. Compound 1 is a new 15,16-dinorerythroxylane-type diterpenoid possessing a C18 skeleton, and 2 is the first example of a 6/6/6/6/5/5-fused hexacyclic ent-kaurane diterpenoid with 19,20-olide and 11,16-epoxy moieties. The structures of the new compounds were elucidated by spectroscopic analysis and chemical methods. The absolute configurations of 1 and 7 were determined by single-crystal X-ray diffraction. Compounds 1-13 were evaluated for their immunosuppressive activity, and 4, 7, and 13 showed moderate inhibitory activities against human B lymphoblast HMy2.CIR cells with IC50 values of 56.3 ± 2.2, 13.3 ± 0.8, and 31.4 ± 0.9 µM, respectively.

Diterpenoids from Salvia miltiorrhiza and Their Immune-Modulating Activity.

Danshen, the dried root of Salvia miltiorrhiza (Lamiaceae), is one of the most popular traditional herbal medicines commonly used in China. Recently, danshen has been used as a health-promoting functional tea to prevent diseases by strengthening the human immunity in China. To search for secondary metabolites with immune-modulating activity, a phytochemical investigation was carried out on the roots of S. miltiorrhiza, which led to the isolation of 6 new diterpenoids (1-4, 16, and 20) along with 20 known diterpenoids. The structures and absolute configurations of these new compounds were elucidated on the basis of spectroscopic analysis, X-ray diffraction analysis, calculated optical rotation, and calculated electronic circular dichroism spectra. Among these isolates, compounds 3, 17, 19, and 23 promoted the proliferation of HMy2.CIR, exhibiting a protective effect on lymphocytes at the concentration from 2.50 to 40 µM, whereas compounds 2, 7, 8, 10, 14, 18, 22, and 25 inhibited the cell proliferation in a concentration-dependent manner.

Dual effects of curcumin on neuronal oxidative stress in the presence of Cu(II).

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders. Elevated copper (Cu) ions are thought to link AD pathology. Curcumin is suggested to treat AD because of its high anti-oxidative activity and coordination to transitional metal ions. In this study, the protective effect of curcumin against the Cu(II)-induced oxidative damage was investigated in primary rat cortical neurons. The neuronal damage was assessed by morphological observation, cell viability, and oxidative stress level. The results showed that curcumin at low dosage protected primary cultured neurons from the 20 µM Cu(II)-induced damage. Low dosage of curcumin depressed oxidative stress levels exacerbated by Cu(II). However, high dosage of curcumin failed to decrease the Cu(II)-induced oxidative stress. When Cu(II) was presented in primary neurons, curcumin at high dosage resulted in chromosomal aberration and cell damage. These results suggest that curcumin, in a concentration-dependent manner, plays both anti-oxidative and pro-oxidative roles in primary neurons treated with Cu(II).

Cu(II) interaction with amyloid-beta peptide: a review of neuroactive mechanisms in AD brains.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the dys-homeostasis of biometal metabolism, the extracellular accumulation of neurotoxic amyloid-beta (Abeta) peptide, the intracellular accumulation of hyperphosphorylated tau and the loss of synapses. Copper plays a key role in AD development. The Abeta peptide and amyloid precursor protein (APP), the parental molecule of Abeta, are modulated by copper in the brain. Increased copper concentration has been found in the AD brain that implies that copper may participate in the pathophysiology of AD. Copper can bind to APP and Abeta, then affects the structure and toxic of APP and Abeta. Some researchers have reported that copper could affect the formation of beta-sheet structure that is widely accepted as toxic secondary structure of Abeta. This review explores the role of copper on the conformation and aggregation of Abeta, and the copper-induced neuroactive mechanisms. Copper may be involved in the following pathways to affect the neuroactivation of Abeta: (1) change of the secondary structure of Abeta; (2) induction of oxidative stress in AD brains, and (3) regulation of cellular signal pathway. Thus, correcting brain copper imbalance may represent a relevant therapeutic target for Alzheimer's disease.

Chitooligosaccharides protect rat cortical neurons against copper induced damage by attenuating intracellular level of reactive oxygen species.

A large number of evidence has suggests that dyshomeostasis of the redox-active biometals such as copper and other metal ions can lead to oxidative stress in neurons, which plays a key role in the pathology of neurodegenerative disorders. Chitooligosaccharides (COSs) are biodegradation product of chitosan and demonstrated diverse biological activities, Here we first report that protective effects of COSs (M.W. 1500, DD. 90%) against Cu(II) induced neurotoxicity in primary cultured rat cortical neurons. The toxicity of Cu(II) to cortical neurons was obviously attenuated in a concentration-dependent manner by COSs pretreated. The data derived from lactate dehydrogenase (LDH) release and the Hoechst 33342 assay support the results from MTT assay. After DCFH assay, COSs were found to depress Cu(II) induced elevation in intracellular reactive oxygen species (ROS), These findings suggest that COSs protect against Cu(II) induced neurotoxicity in primary cortical neurons by interfering with an increase in intracellular reactive oxygen species (ROS).

Impaired dephosphorylation renders G6PD-knockdown HepG2 cells more susceptible to H(2)O(2)-induced apoptosis.

Glucose-6-phosphate dehydrogenase (G6PD) plays a key role in the regeneration of NADPH and maintenance of cellular redox balance. In the present study, we investigate the effect of G6PD deficiency on H(2)O(2)-elicited signaling in HepG2 cells. H(2)O(2) was found to inhibit cellular protein tyrosine phosphatase (PTP) activity, resulting in activation of MAPKs. MKP-1 expression increased in the late phase of H(2)O(2) signaling. Using RNAi technology, we found that G6PD knockdown enhanced the inhibitory effect of H(2)O(2) on PTPs and led to sustained MAPK activation. This was accompanied by delayed expression and inhibition of MKP-1. Using a pharmacological inhibitor and siRNA, we demonstrate that MKP-1 acts as a regulator of MAPK activation in H(2)O(2) signaling. The prolonged MAPK activation in G6PD-knockdown cells was associated with an increased susceptibility to H(2)O(2)-induced apoptosis and growth retardation. Treatment with p38 and JNK inhibitors or N-acetylcysteine ameliorated such cellular effect, while triptolide and MKP-1-siRNA did the opposite. Glucose oxidase treatment had similar effects as addition of H(2)O(2). Taken together, these findings suggest that G6PD knockdown enhances the magnitude and duration of H(2)O(2)-induced MAPK signaling through inhibition of cellular PTPs, and the resultant anomalous signaling may lead to cell demise.

New weakly cytotoxic eremophilane sesquiterpenes from the roots of Ligularia virgaurea.

Six new eremophilane sesquiterpenes, including a novel nortrieremophilane carbon skeleton, were isolated from the roots of Ligularia virgaurea. Their structures were elucidated as 3 alpha,4 alpha-epoxy-6 alpha-(2'-methylacryloyl)oxy-8 alpha-methoxyeremophil-7(11)-en-8 beta,12-olide (1), 3 alpha,4 alpha-epoxy-6 alpha-(2'-methylacryloyl)oxy-8 alpha-ethoxyeremophil-7(11)-en-8 beta,12-olide (2), 1 beta,10 beta-epoxy-6 beta-(2'-methylacryloyl)oxy-8 beta-methoxyeremophil-7(11)-en-8 alpha,12-olide (3), 1 beta,10 beta-epoxy-6 beta-angeloyloxy-8 beta-methoxyeremophil-7(11)-en-8 alpha,12-olide (4), 6 beta-methoxyeremophil-7(11)-en-8 beta,12-olide (5), and 5 beta-angeloyloxy-3a,4,5,6,7,7a-hexahydro-3a beta-methyl-1 H-indene-2,4 beta-dioic acid methyl ester (6) by spectral methods, including IR, HR-ESI-MS, 1D and 2D NMR techniques. All of compounds were evaluated for their in vitro cytotoxic activities against human hepatoma (SMMC-7721), human promyelocytic leukemia (HL-60), and human hepatocyte (L-02) cells.

Cytotoxic germacranolides and acyclic diterpenoides from the seeds of Carpesium triste.

Four new highly oxygenated germacranolides (1, 4, 6, and 7) and four new acyclic diterpenes (8-11), along with three known germacranolides (2, 3, and 5), were isolated from the seeds of Carpesium triste. The structures of the new compounds were elucidated by spectroscopic methods including IR, HRESIMS, and 1D and 2D NMR experiments, and the absolute configurations of compounds 1 and 8-10 were established by CD and Mosher's methods, respectively. Compounds 1, 2, and 4-10 were evaluated for their in vitro cytotoxic activity against cultured SMMC-7721 (human hepatoma), HL-60 (human promyelocytic leukemia), and L02 (human hepatocyte) cell lines. Compounds 1, 2, and 4-7 exhibited significant cytotoxicity against HL-60 cells, and compound 10 exhibited cytotoxicity against SMMC-7721 cells.

Three new triterpenoids from Potentilla multicaulis.

Three new triterpenoids, 19-hydroxy-2,3-secours-12-ene-2,3,28-trioic acid 3- methyl ester (1), 19-hydroxy-1-oxo-2-nor-2,3-secours-12-ene-3,28-dioic acid (2), and (3beta,18alpha,19alpha)-3,28-dihydroxy-20,28-epoxyursan-24-oic acid (3), were isolated from the roots of Potentilla multicaulis. Their structures were elucidated on the basis of spectroscopic methods (IR, HR-ESI-MS, and 1D- and 2D-NMR). Compound 2b exhibited moderate cytotoxic activity against human promyelocytic leukemia (HL-60) cells.

New bisabolane sesquiterpenes and coumarin from Leontopodium longifolium.

From the roots of Leontopotium longifolium, three new bisabolane sesquiterpenes, rel-(1S,4R,5S,6R)-4,5-diacetoxy-6-[(R)-1,5-dimethylhexa-3,5-dienyl]-3-methylcyclohex-2-enyl (Z)-2-methylbut-2-enoate (1), rel-(1S,4R,5S,6R)-4,5-diacetoxy-6-[(R)-5-hydroxy-1,5-dimethylhex-3-enyl]-3-methylcyclohex-2-enyl (Z)-2-methylbut-2-enoate (2), rel-(1R,2S,4R,5S)-4-acetoxy-2-[(R)-5-hydroxy-1,5-dimethylhex-3-enyl]-5-methylcyclohexyl (Z)-2-methylbut-2-enoate (3), and a new coumarin, 2,3-dihydro-5-hydroxy-2-(1-methylethenyl)-7H-pyrano[2,3-g][1,4]benzodioxin-7-one (4) together with nine known compounds have been isolated. The structures of these compounds were established by spectroscopic methods. Compounds 1 and 2 exhibited moderate cytotoxic activities against human promyelocytic leukemia (HL-60) cells.

Triterpenoids and Sesquiterpenes from Mulgedium tataricum.

The chemical investigation of Mulgedium tataricum afforded six new compounds which were identified as lanost-9(11),23 Z(24)-diene-3beta,25-diol (1), lanost-9(11),25-diene-3beta,24beta-diol (2), ursane-20-ene-3beta,22alpha-diol (3), 4 E,10 E-3beta,11beta-dihydroxygermacra-4(5),10(1)-dien-12,6alpha-olide (4), 4 E-1beta-hydroperoxy-3beta,11beta-dihydroxygermacra-4(5),10(14)-dien-12,6alpha-olide (5) and lactucin-8-O-P-methoxyphenyl acetate (6) by using a combination of MS and NMR techniques. Compound 6 exhibited significant cytotoxicity against cultured human hepatoma cells (SMMC-7721) and human acute promyelocytic leukemia cells (HL60). The antibacterial activity study indicated that 1 and 2 strongly inhibited the growth of Escherichia coli.