Differentiation-inducing factor 1 activates cofilin through pyridoxal phosphatase and AMP-activated protein kinase, resulting in mitochondrial fission.

Differentiation-inducing factor 1 (DIF-1) is a morphogen produced by Dictyostelium discoideum that inhibits the proliferation and migration of both D. discoideum and most mammalian cells. Herein, we assessed the effect of DIF-1 on mitochondria, because DIF-3, which is similar to DIF-1, reportedly localizes in the mitochondria when added exogenously, however the significance of this localization remains unclear. Cofilin is an actin depolymerization factor that is activated by dephosphorylation at Ser-3. By regulating the actin cytoskeleton, cofilin induces mitochondrial fission, the first step in mitophagy. Here, we report that DIF-1 activates cofilin and induces mitochondrial fission and mitophagy mainly using human umbilical vein endothelial cells (HUVECs). AMP-activated kinase (AMPK), a downstream molecule of DIF-1 signaling, is required for cofilin activation. Pyridoxal phosphatase (PDXP)-known to directly dephosphorylate cofilin-is also required for the effect of DIF-1 on cofilin, indicating that DIF-1 activates cofilin through AMPK and PDXP. Cofilin knockdown inhibits mitochondrial fission and decreases mitofusin 2 (Mfn2) protein levels, a hallmark of mitophagy. Taken together, these results indicate that cofilin is required for DIF-1- induced mitochondrial fission and mitophagy.

[Progress on the mechanism of n-hexane induced toxic effects in vitro and in vivo].

Hexane is a widely used organic solvent in industry, and chronic hexane poisoning is the main occupational toxic lesion in China. In particular, axonal and myelin lesions in the distal thick fibers of the peripheral nervous system may be caused by 2, 5-hexanedione (2, 5-HD), an intermediate metabolite of n-hexane in humans. Hexane has toxic effects not only on the nervous system but also on the liver, kidneys, and reproductive organs. In this paper, we review the progress of research on the mechanism of n-hexane toxic neuropathy.

Anodic Polymerization of Phenylphenols in Methyl Isobutyl Ketone and Mesityl Oxide: Incorporation of a Cavitand into the Layers Formed for Sensing Phenols in Organic Media.

The electropolymerization of three phenylphenol isomers was studied in methyl isobutyl ketone and mesityl oxide, and the remarkable differences highlighted the importance of the carbon-carbon double bond in mesityl oxide. In the case of each substrate, a brownish deposit formed during the electrooxidation. The obvious difference between the polymers formed from the two solvents was recognized via voltammetric signal enhancement of 4-methoxyphenol and 4-chlorophenol, and it was only observed in the case of mesityl oxide. The experiments highlighted that incorporation of a cavitand with biphenyl groups on the upper rim of the polymers of phenylphenols improved the results to a small extent. The cavitand was, itself, electroactive without any fouling effect. As 2-phenylphenol is by far the cheapest of the three isomers, a cavitand was incorporated into its polymer, which was exploited to solve analytical problems while mesityl oxide was used as solvent. Useful quantifications were achieved in organic solvents; however, it failed under aqueous conditions due to the high hydrophobicity of the deposit. Application of differential pulse voltammetry for 4-methoxyphenol and 4-chlorophenol gave detection limits of 9.28 and 50.8 µM in acetonitrile, respectively. This procedure resulted in the immobilization of cavitand derivatives onto the electrode's surface, and the layer formed offered selective sensing of phenols by electrochemical methods.

Strigolactones and Auxin Cooperate to Regulate Maize Root Development and Response to Nitrate.

In maize, nitrate regulates root development thanks to the coordinated action of many players. In this study, the involvement of strigolactones (SLs) and auxin as putative components of the nitrate regulation of lateral root (LR) was investigated. To this aim, the endogenous SL content of maize root in response to nitrate was assessed by liquid chromatography with tandem mass Spectrometry (LC-MS/MS) and measurements of LR density in the presence of analogues or inhibitors of auxin and SLs were performed. Furthermore, an untargeted RNA-sequencing (RNA-seq)-based approach was used to better characterize the participation of auxin and SLs to the transcriptional signature of maize root response to nitrate. Our results suggested that N deprivation induces zealactone and carlactonoic acid biosynthesis in root, to a higher extent if compared to P-deprived roots. Moreover, data on LR density led to hypothesize that the induction of LR development early occurring upon nitrate supply involves the inhibition of SL biosynthesis, but that the downstream target of SL shutdown, besides auxin, also includes additional unknown players. Furthermore, RNA-seq results provided a set of putative markers for the auxin- or SL-dependent action of nitrate, meanwhile also allowing to identify novel components of the molecular regulation of maize root response to nitrate. Globally, the existence of at least four different pathways was hypothesized: one dependent on auxin, a second one mediated by SLs, a third deriving from the SL-auxin interplay, and a last one attributable to nitrate itself through further downstream signals. Further work will be necessary to better assess the reliability of the model proposed.

3-Hydroxyhexan-2-one and 3-Methylthiopropan-1-ol as Pheromone Candidates for the South American Cerambycid Beetles Stizocera phtisica and Chydarteres dimidiatus dimidiatus, and Six Related Species.

Here, we study the pheromone chemistry of two South American cerambycid beetle species, and their behavioral responses to candidate pheromone components. Adult males of Stizocera phtisica Gounelle (subfamily Cerambycinae: tribe Elaphidiini) produced a sex-specific blend of (R)-3-hydroxyhexan-2-one with lesser amounts of 3-methylthiopropan-1-ol. In field bioassays, traps baited with racemic 3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol did not catch conspecific beetles, but did catch both sexes of a sympatric species, Chydarteres dimidiatus dimidiatus (F.) (Cerambycinae: Trachyderini). We found that males of this species also produce (R)-3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol, and small amounts of 2-phenylethanol. Subsequent bioassays with these compounds showed that a blend of 3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol constitutes the aggregation-sex pheromone of C. d. dimidiatus, with 2-phenylethanol not influencing the attraction of conspecifics. During the field bioassays, six other species in the Cerambycinae also were caught in significant numbers, including Aglaoschema ventrale (Germar) (tribe Compsocerini), congeners Chrysoprasis aurigena (Germar), Chrysoprasis linearis Bates, and an unidentified Chrysoprasis species (Dichophyiini), and Cotyclytus curvatus (Germar) and Itaclytus olivaceus (Laporte & Gory) (both Clytini), suggesting that one or more of the compounds tested are also pheromone components for these species.

Dictyostelium Differentiation-Inducing Factor-1 Promotes Glucose Uptake, at Least in Part, via an AMPK-Dependent Pathway in Mouse 3T3-L1 Cells.

Differentiation-inducing factor-1 (DIF-1) is a chlorinated alkylphenone (a polyketide) found in the cellular slime mold Dictyostelium discoideum. DIF-1 and its derivative, DIF-1(3M) promote glucose consumption in vitro in mammalian cells and in vivo in diabetic rats; they are expected to be the leading antiobesity and antidiabetes compounds. In this study, we investigated the mechanisms underlying the actions of DIF-1 and DIF-1(3M). In isolated mouse liver mitochondria, these compounds at 2-20 µM promoted oxygen consumption in a dose-dependent manner, suggesting that they act as mitochondrial uncouplers, whereas CP-DIF-1 (another derivative of DIF-1) at 10-20 µM had no effect. In confluent mouse 3T3-L1 fibroblasts, DIF-1 and DIF-1(3M) but not CP-DIF-1 induced phosphorylation (and therefore activation) of AMP kinase (AMPK) and promoted glucose consumption and metabolism. The DIF-induced glucose consumption was reduced by compound C (an AMPK inhibitor) or AMPK knock down. These data suggest that DIF-1 and DIF-1(3M) promote glucose uptake, at least in part, via an AMPK-dependent pathway in 3T3-L1 cells, whereas cellular metabolome analysis revealed that DIF-1 and DIF-1(3M) may act differently at least in part.

2,5-Hexanedione influences primordial follicular development in cultured neonatal mouse ovaries by interfering with the PI3K signaling pathway via miR-214-3p.

The mechanisms by which 2,5-hexanedione (2,5-HD) exposure adversely affects reproduction are unclear. In the present study, whole neonatal mouse ovaries were exposed to 2,5-HD in vitro and then assessed for progesterone levels to determine the effects of this compound on ovary function. Ovarian histomorphological analyses were performed to assess the effects of 2,5-HD on follicular development, and PI3K signaling pathway was evaluated to elucidate the molecular mechanisms of 2,5-HD-mediated toxicity on follicular development. The results showed that after ovarian exposure to 2,5-HD in vitro, the percentage of secondary follicles decreased, while the progesterone levels and the percentage of unhealthy follicles increased, with oocytes identified as the target of damage. The 2,5-HD treatment significantly decreased the of the gene encoding the apoptosis-related protein caspase-8, and PI3K/AKT/FOXO3 pathway signaling was also altered. Furthermore, the effects of 2,5-HD on the gene expression of the PI3K/AKT/FOXO3 and follicular development were blocked by 740Y-P (a PI3K activator), miR-214-3p was abnormally expressed, and luciferase reporter assay results demonstrated that the 3' untranslated region of PI3K was a direct target of miR-214-3p. Overall, the results of the present study indicate that 2,5-HD exposure inhibits follicular development, and the underlying mechanism may involve interference with miR-214-3p-mediated regulation of the PI3K signaling pathway.

NGF mediates protection of mesenchymal stem cells-conditioned medium against 2,5-hexanedione-induced apoptosis of VSC4.1 cells via Akt/Bad pathway.

It has been shown that the conditioned medium of bone mesenchymal stem cells (BMSC-CM) can inhibit apoptosis of neural cells exposed to 2,5-hexanedione (HD), but its protective mechanism remains unclear. To investigate the underlying mechanism, VSC4.1 cells were given HD and 5, 10 and 15% BMSC-CM (v/v) in the current experiment. Our data showed that BMSC-CM concentration-dependently attenuated HD-induced cell apoptosis. Moreover, BMSC-CM remarkably decreased the mitochondrial cytochrome c (Cyt C) release and the caspase-3 activity in HD-given VSC4.1 cells. Given a relatively high expression of NGF in BMSCs and BMSC-CM, we hypothesized that NGF might be an important mediator of the protection of BMSC-CM against apoptosis induced by HD. To verify our hypothesis, the VSC4.1 cells were administrated with NGF and anti-NGF antibody in addition to HD. As expected, NGF could perfectly mimic BMSC-CM's protective role and these beneficial effects were abolished by anti-NGF antibody intervention. To further explore its mechanism, inhibitors of TrkA and Akt were given to the VSC4.1 cells and NGF/Akt/Bad pathway turned out to be involved in anti-apoptotic role of BMSC-CM. Based on these findings, it was revealed that BMSC-CM beneficial role was mediated by NGF and relied on the Akt/Bad pathway.

Pheromone Chemistry of the Citrus Borer, Diploschema rotundicolle (Coleoptera: Cerambycidae).

The citrus borer, Diploschema rotundicolle, is a Neotropical longhorn beetle that has become a serious citrus pest in southern South America. Management strategies for this insect rely on trimming off damaged shoots, which is expensive and inefficient. We studied the chemical communication system in D. rotundicolle in search of attractants for monitoring or control. GC-MS and enantioselective GC analyses of volatile extracts from field-collected adults showed that males produce (R)-3-hydroxy-2-hexanone, irregularly accompanied by minor amounts of 2,3-hexanediol (all four stereoisomers) and 2,3-hexanedione. Males emit the compounds only at night, when the adults are active. GC-EAD analyses of natural and synthetic compounds showed that both male and female antennae respond to the natural enantiomer (R)-3-hydroxy-2-hexanone, suggesting that it may function as an aggregation-sex pheromone as seen in many cerambycines. The non-natural (S) enantiomer as well as the minor component 2,3-hexanediol did not trigger antennal responses. Field tests with the racemic 3-hydroxy-2-hexanone, enantiomerically pure (R)-3-hydroxy-2-hexanone, as well as a mixture of racemic 3-hydroxy-2-hexanone and 2,3-hexanediol, showed in all cases low capture levels of D. rotundicolle. However, increasing the elevation of the trap and the emission rate of dispensers enhanced field captures in traps baited with racemic hydroxyketone. Incidental catches of another native cerambycine, Retrachydes thoracicus, in traps baited with 3-hydroxy-2-hexanone are also reported. This is the first report of pheromone chemistry in the genus Diploschema and in the tribe Torneutini, reaffirming the pheromone parsimony well established for the Cerambycinae. Potential factors explaining the weak attraction of D. rotundicolle in the field are discussed.

Synthesis and antioxidant activities of phenol derivatives from 1,6-bis(dimethoxyphenyl)hexane-1,6-dione.

Starting from the compound (3,4-dimethoxyphenyl)(2-(3,4-dimethoxyphenyl)cyclopent-1-en-1-yl)methanone (4), two diols and three tetrol derivatives were synthesised. Morover, from the reactions of 1,3-dimethoxybenzene and 1,4-dimethoxybenzene with adipoyl chloride, fifteen new along with nine known compounds were obtained. For the characterizations of compounds, spectroscopic methods such as NMR including DEPT, COSY, HMQC and HMBC experiments and X-ray diffraction were used. The antioxidant activities of novel synthesized seventeen molecules were investigated by analytical methods like ABTS•+ and DPPH• scavenging. Also, reducing power these molecules were investigated by Fe3+, Cu2+, and [Fe3+-(TPTZ)2]3+. Some of the molecules record powerful antioxidant profile when compared to putative standards. The inhibition effects of the phenols compounds against AChE and BChE activities were analysed. Also, these phenols were found as effective inhibitors for AChE, hCA I, hCA II, and BChE with Kis in the range of 122.95 ± 18.41-351.31 ± 69.12 nM for hCA I, 62.35 ± 9.03-363.17 ± 180.1 nM for hCA II, 134.57 ± 3.99-457.43 ± 220.10 nM for AChE, and 27.06 ± 9.12-72.98 ± 9.53 nM for BChE, respectively.

Modulatory role of rutin on 2,5-hexanedione-induced chromosomal and DNA damage in rats: validation of computational predictions.

The aim of this study was to evaluate the potentials of rutin on 2,5-hexanedione-induced toxicities. Two successive phases were involved using in silico and in vivo approaches. The in silico was adopted for potential oral toxicity and docking. The in vivo was carried-out in two stages for two weeks; the ameliorative (stage 1, first week), preventive, and curative studies (stage 2, extended to second week). In stage 1, rats were divided into four groups of seven each (distilled water, 3% (v/v) 2,5-hexanedione, 10 mg/kg rutin, and co-administration). In stage 2, the experimental groups were given either rutin or 2,5-hexanedione and treated in reverse order. Lipid peroxidation, protein carbonyl, and DNA fragmentation in tissues and bone marrow cells micronucleus were determined. The predicted Median lethal dose (LD50) of >5000 mg/kg and toxicity class of five (5) indicates the safety of rutin when orally administered. 2,5-Hexanedione comfortably docked in to the active sites of SOD (-22.857Kcal/mol; KI = 0.9621 µM), GPx (-11.2032Kcal/mol; KI = 0.9813 µM), and CAT (-16.446Kcal/mol; KI = 0.9726 µM) with strong hydrogen bond and hydrophobic interactions. However, only strong hydrophobic interaction was observed in the case of DNA (-3.3296Kcal/mol; KI = 0.9944). In vivo findings revealed deleterious effects of 2,5-hexanedione through induction of oxidative and chromosomal/DNA damage characterized by higher level of malondialdehyde, micronuclei formations, and DNA fragmentation. These have invariably, validates the findings from in silico experiments. Furthermore, rutin was able to ameliorate, protect, and reverse these effects, and was relatively non-toxic corroborating toxicity predictions. Rutin exhibited counteractive effects on 2,5-hexanedione-induced oxidative, chromosomal, and DNA damage.

Preparation of 1-Hydroxy-2,5-hexanedione from HMF by the Combination of Commercial Pd/C and Acetic Acid.

The development of a simple and durable catalytic system for the production of chemicals from a high concentration of a substrate is important for biomass conversion. In this manuscript, 5-hydroxymethylfurfural (HMF) was converted to 1-hydroxy-2,5-hexanedione (HHD) using the combination of commercial Pd/C and acetic acid (AcOH) in water. The influence of temperature, H2 pressure, reaction time, catalyst amount and the concentration of AcOH and HMF on this transformation was investigated. A 68% yield of HHD was able to be obtained from HMF at a 13.6 wt% aqueous solution with a 98% conversion of HMF. The resinification of intermediates on the catalyst was characterized to be the main reason for the deactivation of Pd/C. The reusability of the used Pd/C was studied to find that most of the activity could be recovered by being washed in hot tetrahydrofuran.

Tris(2-Aminoethyl)Amine/Metal Oxides Hybrid Materials-Preparation, Characterization and Catalytic Application.

Three different metal oxides (basic MgO, basic-acidic Al2O3 and acidic-basic Nb2O5) characterized by comparable surface areas (MgO-130 m2/g; Al2O3-172 m2/g and Nb2O5-123 m2/g) and pore systems (domination of mesopores with narrow pore size distribution) were modified with tris(2-aminoethyl)amine (TAEA) via two methods: (i) direct anchoring of amine on metal oxide and (ii) anchoring of amine on metal oxide functionalized with (3-chloropropyl)trimethoxysilane. The obtained hybrid materials were characterized in terms of effectiveness of modifier anchoring (elemental analysis), their structural/textural properties (nitrogen adsorption/desorption, XRD), acidity/basicity of support (2-propanol dehydration and dehydrogenation, dehydration and cyclization of 2,5-hexanedione), states of modifier deposited on supports (XPS, FTIR, UV-VIS) and the strength of interaction between the modifier and the support (TG/DTG). It was evidenced that acidic-basic properties of metal oxides as well as the procedure of modification with TAEA determined the ways of amine anchoring and the strength of its interaction with the support. The obtained hybrid materials were tested in Knoevenagel condensation between furfural and malononitrile. The catalysts based on MgO showed superior activity in this reaction. It was correlated with the way of TAEA anchoring on basic MgO and the strength of modifier anchoring on the support. To the best of our knowledge tris(2-aminoethyl)amine has not been used as a modifier of solid supports for enhancement of the catalyst activity in Knoevenagel condensation.

[Effects of 2, 5-hexanedione on S100ß of Schwann cells in rat sciatic nerves].

OBJECTIVE: To investigate the expression of S100ß protein and mRNA of Schwann cells(SC) in sciatic nerves of 2, 5-hexanedione(HD) intoxicated rats. METHODS: Nine-week old SPF male Wistar rats were administered at daily dosing of 100 and 300 mg/kg by intraperitoneal injection for continuous 8 weeks(five times every week). Age-matched control rats received an equivalent volume of normal saline. Ten rats in each group were sacrificed and sciatic nerves were excised for S100ß determination, with excised sciatic nerves from another three rats for morphological observation through electron microscope. At the end of the exposure, the other 8-week treated animals were allowed to naturally recover for 8 weeks and sciatic nerves were excised at the end of the test. S100ß protein contents were determined by immunohistochemistry method, and mRNA expression was observed by real-time quantitative polymerase chain reaction(PCR). RESULTS: HD intoxication with 300 mg/kg was associated with severe neurological deficits of paralysis in hindlimbs, accompanied with evident movement gait abnormalities for 100 mg/kg dosage. The morphological abnormalities in myelin sheath of sciatic nerves were observed through electron microscope after HD-exposure. The S100ß contents in 100 mg/kg and 300 mg/kg groups remained relatively unaffected with 92% and 79% of the control respectively after HD-intoxication, and a increase to 149%(P<0. 05) and 119% after a recovery of 8 weeks was accompanied with. As to S100ß mRNA, HD-intoxication was associated with decreased expression to 0. 65(P<0. 05) and 0. 56 times(P<0. 05) of the control, and 1. 46 and 0. 87 times for 8-week recovery individually. CONCLUSION: The S100ß protein and mRNA levels were influenced by HD exposure, and the result suggested that S100ß might be involved in HD-induced peripheral axonopathy.

Differentiation-inducing factor-1 suppresses cyclin D1-induced cell proliferation of MCF-7 breast cancer cells by inhibiting S6K-mediated signal transducer and activator of transcription 3 synthesis.

Differentiation-inducing factor-1 (DIF-1) has been reported to inhibit the proliferation of various mammalian cells by unknown means, although some possible mechanisms of its action have been proposed, including the activation of glycogen synthase kinase-3 (GSK-3). Here, we report an alternative mechanism underlying the action of DIF-1 in human breast cancer cell line MCF-7, on which the effects of DIF-1 have not been examined previously. Intragastric administration of DIF-1 reduced the tumor growth from MCF-7 cells injected into a mammary fat pad of nude mice, without causing adverse effects. In cultured MCF-7, DIF-1 arrested the cell cycle in G0 /G1 phase and suppressed cyclin D1 expression, consistent with our previous results obtained in other cell species. However, DIF-1 did not inhibit the phosphorylation of GSK-3. Investigating an alternative mechanism for the reduction of cyclin D1, we found that DIF-1 reduced the protein levels of signal transducer and activator of transcription 3 (STAT3). The STAT3 inhibitor S3I-201 suppressed cyclin D1 expression and cell proliferation and the overexpression of STAT3 enhanced cyclin D1 expression and accelerated proliferation. Differentiation-inducing factor-1 did not reduce STAT3 mRNA or reduce STAT3 protein in the presence of cycloheximide, suggesting that DIF-1 inhibited STAT3 protein synthesis. Seeking its mechanism, we revealed that DIF-1 inhibited the activation of 70 kDa and/or 85 kDa ribosomal protein S6 kinase (p70S6K /p85S6K ). Inhibition of p70S6K /p85S6K by rapamycin also reduced the expressions of STAT3 and cyclin D1. Therefore, DIF-1 suppresses MCF-7 proliferation by inhibiting p70S6K /p85S6K activity and STAT3 protein synthesis followed by reduction of cyclin D1 expression.

Differentiation-inducing factor-1 prevents hepatic stellate cell activation through inhibiting GSK3ß inactivation.

Differentiation-inducing factor-1 (DIF-1), a morphogen produced by the cellular slime mold Dictyostelium discoideum, is a natural product that has attracted considerable attention for its antitumor properties. Here, we report a novel inhibitory effect of DIF-1 on the activation of hepatic stellate cells (HSCs) responsible for liver fibrosis. DIF-1 drastically inhibited transdifferentiation of quiescent HSCs into myofibroblastic activated HSCs in a concentration-dependent manner, thus conferring an antifibrotic effect against in the liver. Neither SQ22536, an adenylate cyclase inhibitor, nor ODQ, a guanylate cyclase inhibitor, showed any effect on the inhibition of HSC activation by DIF-1. In contrast, TWS119, a glycogen synthase kinase 3ß (GSK3ß) inhibitor, attenuated the inhibitory effect of DIF-1. Moreover, the level of inactive GSK3ß (phosphorylated at Ser9) was significantly reduced by DIF-1. DIF-1 also inhibited nuclear translocation of ß-catenin and reduced the level of non-phospho (active) ß-catenin. These results suggest that DIF-1 inhibits HSC activation by disrupting the Wnt/ß-catenin signaling pathway through dephosphorylation of GSK3ß. We propose that DIF-1 is a possible candidate as a therapeutic agent for preventing liver fibrosis.

Strigolactones enhance root-knot nematode (Meloidogyne graminicola) infection in rice by antagonizing the jasmonate pathway.

Strigolactones (SLs) are carotenoid-derived plant hormones that also act in the rhizosphere to stimulate germination of root-parasitic plants and enhance plant symbiosis with beneficial microbes. Here, the role of SLs was investigated in the interaction of rice (Oryza sativa) roots with the root-knot nematode Meloidogyne graminicola. Genetic approaches and chemical sprays were used to manipulate SL signaling in rice before infection with M. graminicola. Then, nematode performance was evaluated and plant defense hormones were quantified. Meloidogyne graminicola infection induced SL biosynthesis and signaling and suppressed jasmonic acid (JA)-based defense in rice roots, suggesting a potential role of SLs during nematode infection. Whereas the application of a low dose of the SL analogue GR24 increased nematode infection and decreased jasmonate accumulation, the SL biosynthesis and signaling d mutants were less susceptible to M. graminicola, and constitutively accumulated JA and JA-isoleucine compared with wild-type plants. Spraying with 0.1 µM GR24 restored nematode susceptibility in SL-biosynthesis mutants but not in the signaling mutant. Furthermore, foliar application of the SL biosynthesis inhibitor TIS108 impeded nematode infection and increased jasmonate levels in rice roots. In conclusion, SL signaling in rice suppresses jasmonate accumulation and promotes root-knot nematode infection.

NGF protects bone marrow mesenchymal stem cells against 2,5-hexanedione-induced apoptosis in vitro via Akt/Bad signal pathway.

Mesenchymal stem cell transplantation has been proposed as a promising therapy for regeneration of damaged tissues-especially, bone marrow mesenchymal stem cell (BMSC) transplantation therapy is considered to be an effective strategy for treating various injures in recent years. However, poor viability of transplanted BMSCs in injured tissues has limited their therapeutic efficiency. Nerve growth factor (NGF) has been reported to be a pro-survival factor in series of cells. Moreover, NGF could improve BMSC viability and activate anti-apoptotic pathway. Therefore, we are interested to know whether NGF promoted BMSC survival in transplanted tissue. In this study, we investigated the protective effect and potential mechanisms of NGF against apoptosis of BMSCs in vitro. 2,5-hexanedione (HD) was the apoptosis inducer. BMSCs were treated with 40 mM HD and different concentrations of NGF (0, 50, 100, 200 µg/L) together for 24 h. Results showed that NGF treatment increased the viability of BMSCs exposed to HD. Moreover, NGF effectively suppressed HD-induced apoptosis which was characterized by inhibiting caspase-3 activity, as well as mitochondrial transmembrane potential depolarization. Mechanistically, it was found that NGF promoted phosphorylation of Akt and Bad, which is TrkA dependent. However, K252a and MK-2206 (TrkA and Akt inhibitor, respectively) suppressed the anti-apoptosis of NGF, indicating the protective effect of NGF on BMSCs apoptosis via a novel Akt/Bad pathway. The findings suggested that NGF may be used as an effective protective agent against BMSC apoptosis so as to promote the survival rate of transplanted BMSCs and their tissue repair capability.

The Male-Produced Aggregation-Sex Pheromone of the Cerambycid Beetle Plagionotus detritus ssp. detritus.

The number of longhorn beetles with confirmed aggregation-sex pheromones has increased rapidly in recent years. However, the species that have been studied most intensively are pests, whereas much less is known about the pheromones of longhorn beetles that are rare or threatened. We studied the cerambycid beetle Plagionotus detritus ssp. detritus with the goal of confirming the presence and composition of an aggregation-sex pheromone. This species has suffered widespread population decline due to habitat loss in Western Europe, and it is now considered threatened and near extinction in several countries. Beetles from a captive breeding program in Sweden were used for headspace sampling. Gas chromatography-mass spectrometry revealed that collections from males contained large quantities of two compounds, identified as (R)-3-hydroxy-2-hexanone (major component) and (S)-2-hydroxy-3-octanone (minor component), in addition to smaller quantities of 2,3-hexanedione and 2,3-octanedione. None of the compounds was present in collections from females. When tested singly in a field bioassay, racemic 3-hydroxy-2-hexanone and 2-hydroxy-3-octanone were not attractive to P. detritus, whereas a 5:1 blend elicited significant attraction. Both compounds are known as components of the pheromones of conspecific beetles, but, to our knowledge, this is the first cerambycid shown to use two compounds with different chain lengths, in which the positions of the hydroxyl and carbonyl functions are interchanged between the two. The pheromone has potential as an efficient tool to detect and monitor populations of P. detritus, and may also be useful in more complex studies on the ecology and conservation requirements of this species.

Common Cerambycid Pheromone Components as Attractants for Longhorn Beetles (Cerambycidae) Breeding in Ephemeral Oak Substrates in Northern Europe.

Longhorn beetles are ecologically important insects in forest ecosystems as decomposers of woody substrates, microhabitat engineers, and as components of forest food webs. These species can be greatly affected both positively and negatively by modern forestry management practices, and should be monitored accordingly. Through headspace sampling, coupled gas chromatography-electroantennography, gas chromatography-mass spectrometry, and field bioassays, we identified two compounds, 2-methyl-1-butanol and 3-hydroxy-2-hexanone, that constitute aggregation-sex pheromone attractants of three cerambycid species which breed primarily in different types of fresh, recently dead oak wood in Northern Europe: Pyrrhidium sanguineum (L.), Phymatodes alni ssp. alni (L.), and Phymatodes testaceus (L.) (Cerambycinae: Callidiini). Analyses of headspace volatiles collected from live insects indicated that the male-produced aggregation-sex pheromone of P. sanguineum is a 1-15:100 blend of (R)-2-methyl-1-butanol and (R)-3-hydroxy-2-hexanone, whereas the corresponding ratios for P. alni were 70-110:100. In field bioassays, adult P. sanguineum and P. alni were significantly attracted to multiple blends with varying ratios of the two compounds. When tested individually, the compounds were minimally attractive. In contrast, adult P. testaceus exhibited nonspecific attraction to both of the individual compounds and to different blends, despite the hydroxyketone not being part of its pheromone, which consists of (R)-2-methyl-1-butanol alone. Overall, our results suggest that a blend of 50:100 of racemic 2-methyl-1-butanol and 3-hydroxy-2-hexanone is appropriate for parallel, cost-efficient pheromone-based monitoring of all three species. In particular, these species could serve as useful indicators of how modern forestry practices affect a whole guild of saproxylic insects that require ephemeral deadwood substrates for successful breeding.