Rice volatile compound (E)-ß-caryophyllene induced by rice dwarf virus (RDV) attracts the natural enemy Cyrtorhinus lividipennis to prey on RDV insect vectors.

BACKGROUND: Rice dwarf virus (RDV)-induced rice plant volatiles (E)-ß-caryophyllene and 2-heptanol modulate the olfactory behavior of RDV insect vectors that promote viral acquisition and transmission. However, it remains elusive whether these two volatiles could influence the behaviors of the natural enemies of RDV insect vectors. Herein, we determined the effects of these two volatiles on the olfactory and predatory behaviors of Cyrtorhinus lividipennis (Hemiptera: Miridae), an important predator of RDV insect vectors in rice paddies. RESULTS: The results showed that C. lividipennis preferred RDV-infected rice plant odors over RDV-free rice plant odors. C. lividipennis was attracted by (E)-ß-caryophyllene, but showed no behavioral responses to 2-heptanol. The attraction of (E)-ß-caryophyllene towards C. lividipennis was further confirmed using oscas1 rice plants, which do not release (E)-ß-caryophyllene in response to RDV infection, through a series of complementary assays. The oviposition preference of the RDV vector insect Nephotettix cincticeps (Hemiptera: Cicadellidae) showed no significant difference between RDV-infected and RDV-free wild-type plants, nor between oscas1-RDV and oscas1 plants. However, the predation rate of C. lividipennis for N. cincticeps eggs on RDV-infected plants was higher than that on RDV-free plants, whereas there was no significant difference between oscas1-RDV and oscas1 plants. CONCLUSION: (E)-ß-caryophyllene induced by RDV attracted more C. lividipennis to prey on N. cincticeps eggs and played a crucial role in plant-virus-vector-enemy interactions. These novel findings will promote the design of new strategies for disease control by controlling the populations of insect vectors, for example recruiting more natural enemies by virus-induced plant volatiles. © 2023 Society of Chemical Industry.

Comparative flavor precursors and volatile compounds of Wenchang chickens fed with copra meal based on GC-O-MS.

In the Wenchang chicken (WC) feeding process, copra meal is often added to improve chicken quality. To determine the effect of feeding with copra meal on the flavor formation of WCs, the experimental subjects were fed with 4.5 % and 7.5 % copra meal, and the control group was fed without copra meal. The electronic nose combined with gas chromatography-olfactometry mass spectrometry (GC-O-MS) was used to identify the volatile compounds from the samples. Compared with the control group, the pH of chickens fed copra meal was significantly decreased (P < 0.05) after slaughter. Aldehydes and alcohols were the main volatile compounds in muscle, among which hexanal and 1-octen-3-ol were the highest. Thirty-two and thirty-six compounds were identified in breast muscle and drumstick muscle, respectively. Twelve new volatile compounds were added, including 1-octanol, butanal, 1-heptanol, 3-ethylbenzaldehyde, 2,2-dimethylpentanal, hexanoic acid, 3-heptanone, 2,5-heptanedione, 2-ethylfuran, 2-propylfuran, 2-ethynylpyridine, and 1,2,4,5-tetrazine. The types and contents of volatile compounds in drumstick muscle increased with an increasing proportion of copra meal in the diet. In summary, the addition of copra meal changed the quality of WCs and increased the types and contents of volatile compounds. This study provides a reference for understanding the flavor profile of WC fed copra meal.

P20-A129†An innovative wound healing method reveals a donor and post-mortem time-dependent regeneration of corneal epithelium.

PURPOSE: The aim of this study was to establish and optimize a new and reproducible epithelial wound healing model on human corneas. This assay was used to study the kinetics of epithelial regeneration following a chemical injury. METHODS: Thirty (n=30) human corneas unsuitable for transplant were used for the experiments. Corneas were cultured in Storagix medium (FBOV) at 31°C. Epithelial integrity before the beginning of the experiments (pre-wound) was assessed using the vital dyes trypan blue (TB, TB-S 0.25%, AL.CHI.MI.A. srl) and sodium fluorescein (Fluo). 1-heptanol soaked paper disks (6 mm) were applied in the centre of the corneas for 1' to trigger a chemical damage at the epithelial layer. Afterwards, sodium fluorescein and TB stainings were repeated to quantify the damaged area and to monitor healing progression. The damaged area (mm2) was calculated for each time point with Fiji software. Wound healing rate (HR, mm2/die) was calculated for both Fluo (HRF) and TB (HRTB) measurements using the previously described formula:Arithmetical averages (HRFAVG and HRTBAVG) of HRs were calculated and correlated by Pearson correlation coefficient with the following donor's parameters: age, sex, post-mortem time (PMT, time between death and tissue procurement), stromal defects, septicaemia, body temperature, diabetes. RESULTS: The execution of the heptanol wounding is highly reproducible, as highlighted by Fluo and TB staining. The average time for full recovery from wounding was 3,8 ± 0,41 days for Fluo and 3,5 ± 0,63 days for TB. Fluo and TB stainings are interchangeable as they significantly correlate (Pearson correlation coefficient = 0.630; p>0.05). A negative linear correlation was observed between HR and PMT (HRFAVG: corrected R2: 0.243, p = 0.003; HRTBAVG: corrected R2: 0,132, p = 0.028), but not with the other donors' parameters. CONCLUSION: Our wound/healing model might be of great interest for studies of epithelial regeneration kinetics and validation of drugs for the treatment of ocular defects. The inverse correlation between PMT and HR provides valuable insights for scientists investigating the regenerative properties of the corneal epithelium, as well as for eye bank personnel aiming to preserve the regenerative potential of corneal epithelium.

Enhanced Membrane Fluidization and Cholesterol Displacement by 1-Heptanol Inhibit Mast Cell Effector Functions.

Signal transduction by the high-affinity IgE receptor (FcεRI) depends on membrane lipid and protein compartmentalization. Recently published data show that cells treated with 1-heptanol, a cell membrane fluidizer, exhibit changes in membrane properties. However, the functional consequences of 1-heptanol-induced changes on mast cell signaling are unknown. This study shows that short-term exposure to 1-heptanol reduces membrane thermal stability and dysregulates mast cell signaling at multiple levels. Cells treated with 1-heptanol exhibited increased lateral mobility and decreased internalization of the FcεRI. However, this did not affect the initial phosphorylation of the FcεRI-ß chain and components of the SYK/LAT1/PLCγ1 signaling pathway after antigen activation. In contrast, 1-heptanol inhibited SAPK/JNK phosphorylation and effector functions such as calcium response, degranulation, and cytokine production. Membrane hyperfluidization induced a heat shock-like response via increased expression of the heat shock protein 70, increased lateral diffusion of ORAI1-mCherry, and unsatisfactory performance of STIM1-ORAI1 coupling, as determined by flow-FRET. Furthermore, 1-heptanol inhibited the antigen-induced production of reactive oxygen species and potentiated stress-induced plasma membrane permeability by interfering with heat shock protein 70 activity. The combined data suggest that 1-heptanol-mediated membrane fluidization does not interfere with the earliest biochemical steps of FcεRI signaling, such as phosphorylation of the FcεRI-ß chain and components of the SYK/LAT/PLCγ1 signaling pathway, instead inhibiting the FcεRI internalization and mast cell effector functions, including degranulation and cytokine production.

Enhancing the activity of a monomeric alcohol dehydrogenase for site-specific applications by site-directed mutagenesis.

Gene fusion or co-immobilization are key tools to optimize enzymatic reaction cascades by modulating catalytic features, stability and applicability. Achieving a defined spatial organization between biocatalysts by site-specific applications is complicated by the involvement of oligomeric enzymes. It can lead to activity losses due to disturbances of the quaternary structures and difficulties in stoichiometric control. Thus, a toolkit of active and robust monomeric enzymes is desirable for such applications. In this study, we engineered one of the rare examples of monomeric alcohol dehydrogenases for improved catalytic characteristics by site-directed mutagenesis. The enzyme from the hyperthermophilic archaeon Thermococcus kodakarensis naturally exhibits high thermostability and a broad substrate spectrum, but only low activity at moderate temperatures. The best enzyme variants showed an ~5-fold (2-heptanol) and 9-fold (3-heptanol) higher activity while preserving enantioselectivity and good thermodynamic stability. These variants also exhibited modified kinetic characteristics regarding regioselectivity, pH dependence and activation by NaCl.

Cx43-Delivered miR-181b Negatively Regulates Sirt1/FOXO3a Signalling Pathway-Mediated Apoptosis on Intestinal Injury in Sepsis.

INTRODUCTION: Gap junctions can transmit signals between cells, including miRNAs, leading to the amplification of adjacent cell damage. No previous study has addressed gap junctions and miRNAs in sepsis because the internal mechanism of sepsis-induced intestinal injury is complex. Therefore, we studied the relationship between connexin43 (Cx43) and miR-181b and provided a research direction for further study of sepsis. METHODS: A mouse caecal ligation and puncture method was used to construct a mouse sepsis model. Firstly, damage to intestinal tissues at different time points was analysed. The levels of Cx43, miR-181b, Sirt1, and FOXO3a in intestinal tissues and the transcription and translation of the apoptosis-related genes Bim and puma, which are downstream of FOXO3a were analysed. Secondly, the effect of Cx43 levels on miR-181b and Sirt1/FOXO3a signalling pathway activity was explored by using the Cx43 inhibitor heptanol. Finally, luciferase assays were used to determine miR-181b binding to the predicted target sequence. RESULTS: The results show that during sepsis, intestinal injury becomes increasingly worse with time, and the expression of Cx43 and miR-181b increase. In addition, we found that heptanol could significantly reduce intestinal injury. This finding indicates that inhibiting Cx43 regulates the transfer of miR-181b between adjacent cells, thereby reducing the activity of the Sirt1/FOXO3a signalling pathway and reducing the degree of intestinal injury during sepsis. CONCLUSIONS: In sepsis, the enhancement of Cx43 gap junctions leads to an increase in miR-181b intercellular transfer, affects the downstream SIRT1/FOXO3a signalling pathway and causes cell and tissue damage.

Association of lipidome evolution with the corresponding volatile characteristics of postmortem lamb during chilled storage.

This investigation aims to elucidate the roles of lipids on the volatilome evolution of postmortem lamb and its possible modulated mechanism behind. Firstly, the physicochemical properties were evaluated as coordinating role of flavor quality, and results suggested that chilled storage improved tenderness of muscle tissue and induced color variation of lamb. According to multivariate results, the pattern shifts of volatile profile of chilled lamb could be differentiated successfully. Besides, the potential differential aroma-active compounds were identified, including up-regulated heptanol, 1-octen-3-ol, 6-methyl-2-heptanone, 3-heptanone, 2-pentyl furan and octanol in early stage of storage (days 0-3) and down-regulated hexanal, pentanal, hexanol, octanol, 6-methy-2-heptanone, heptanol, 1-octen-3-ol and benzaldehyde in later stage of storage (days 3-7). Then, discriminant analysis recognized the differential lipid species corresponding to different stages of lamb flavor development, involving phospholipids, sphingolipids, glycerolipids and fatty acyls. Herein, the degradation of acyl carnitine and diglyceride may be an important pathway that contributed to volatilome evolution of postmortem lamb in the early stage of storage. These results demonstrated a potential relationship between headspace volatilome and lipidome evolutions, providing a comprehensive understanding for development of lipid-derived volatile compounds of chilled lamb and useful for lamb characteristic flavor quality evaluation and control in future.

The Alarm Pheromone and Alarm Response of the Clonal Raider Ant.

Ants communicate via an arsenal of different pheromones produced in a variety of exocrine glands. For example, ants release alarm pheromones in response to danger to alert their nestmates and to trigger behavioral alarm responses. Here we characterize the alarm pheromone and the alarm response of the clonal raider ant Ooceraea biroi, a species that is amenable to laboratory studies but for which no pheromones have been identified. During an alarm response, ants quickly become unsettled, leave their nest pile, and are sometimes initially attracted to the source of alarm, but ultimately move away from it. We find that the alarm pheromone is released from the head of the ant and identify the putative alarm pheromone as a blend of two compounds found in the head, 4-methyl-3-heptanone and 4-methyl-3-heptanol. These compounds are sufficient to induce alarm behavior alone and in combination. They elicit similar, though slightly different behavioral features of the alarm response, with 4-methyl-3-heptanone being immediately repulsive and 4-methyl-3-heptanol being initially attractive before causing ants to move away. The behavioral response to these compounds in combination is dose-dependent, with ants becoming unsettled and attracted to the source of alarm pheromone at low concentrations and repulsed at high concentrations. While 4-methyl-3-heptanone and 4-methyl-3-heptanol are known alarm pheromones in other more distantly related ant species, this is the first report of the chemical identity of a pheromone in O. biroi, and the first alarm pheromone identified in the genus Ooceraea. Identification of a pheromone that triggers a robust, consistent, and conserved behavior, like the alarm pheromone, provides an avenue to dissect the behavioral and neuronal mechanisms underpinning chemical communication.

Virus-Induced Plant Volatiles Promote Virus Acquisition and Transmission by Insect Vectors.

Rice dwarf virus (RDV) is transmitted by insect vectors Nephotettix virescens and Nephotettix cincticeps (Hemiptera: Cicadellidae) that threatens rice yield and results in substantial economic losses. RDV induces two volatiles ((E)-ß-caryophyllene (EBC) and 2-heptanol) to emit from RDV-infected rice plants. However, the effects of the two volatiles on the olfactory behavior of both non-viruliferous and viruliferous N. virescens are unknown, and whether the two volatiles could facilitate the spread and dispersal of RDV remains elusive. Combining the methods of insect behavior, chemical ecology, and molecular biology, we found that EBC and 2-heptanol influenced the olfactory behavior of non-viruliferous and viruliferous N. virescens, independently. EBC attracted non-viruliferous N. virescens towards RDV-infected rice plants, promoting virus acquisition by non-viruliferous vectors. The effect was confirmed by using oscas1 mutant rice plants (repressed EBC synthesis), but EBC had no effects on viruliferous N. virescens. 2-heptanol did not attract or repel non-viruliferous N. virescens. However, spraying experiments showed that 2-heptanol repelled viruliferous N. virescens to prefer RDV-free rice plants, which would be conducive to the transmission of the virus. These novel results reveal that rice plant volatiles modify the behavior of N. virescens vectors to promote RDV acquisition and transmission. They will provide new insights into virus-vector-plant interactions, and promote the development of new prevention and control strategies for disease management.

Inoculation of yeast and bacterium in wet-processed Coffea canephora.

This study evaluated the inoculation of Meyerozyma guilliermondii and Bacillus licheniformis, separately or in co-culture, in wet-processed conilon coffee. Wet fermentation was conducted for 48 h. Mesophilic bacteria, lactic acid bacteria, yeasts, and filamentous fungi were counted during fermentation. The inoculation of B. licheniformis and M. guilliermondii stimulated the multiplication of lactic acid bacteria. Acetic, citric, lactic, oxalic, malic, succinic, tartaric acids, glucose, and fructose were identified in all treatments at different concentrations. Methyl salicylate, 2-heptanol, 2-nonanol, and heptanone were found during fermentation. Methylpyrazine, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, and 3-ethyl-2,5-dimethylpyrazine identified after roasting assigned notes of "almond" and "chocolate" to the beverages. All treatments were classified as "premium," with the B. licheniformis treatment receiving the highest score. Bacillus licheniformis obtained better performance in fermentation, increasing coffee score and producing volatile compounds that provided positive sensory notes to the beverage.

The Role of Gap Junctions in the Generation of Smooth Muscle Cells from Bone Marrow Mesenchymal Stem Cells.

Background: Studies have shown that stem cell transplantation can improve smooth muscle cell (SMC) regeneration and remodelling. Gap junctions can enhance the cytoprotective effects of neighbouring cells. We investigated the effect of gap junctions on the differentiation of bone marrow mesenchymal stem cells (BMSCs) into SMCs. Materials and Methods: Rat BMSCs and SMCs were obtained from the bone marrow and bladder of Sprague-Dawley rats, respectively. Flow cytometry and multilineage differentiation were performed to assess the characteristics of these cells. BMSCs and SMCs were incubated together in cocultures in the presence and absence of heptanol, an uncoupler of gap junctions. Cocultures were divided into three groups consisting of a contact coculture, noncontact coculture, and contact coculture plus heptanol groups. The expression of BMSC-specific markers and the effect of gap junctions on the differentiation of BMSCs were evaluated by performing real-time reverse transcription-polymerase chain reaction, immunofluorescence analysis, and western blotting after cocultures. Results: CD90 and CD44 were markedly expressed, and CD31 and CD45 were weakly or not expressed in BMSCs. The cells also showed good osteogenic and adipogenic differentiation ability. Compared with the noncontact coculture group, the SMC markers such as α-SMA, calponin, and connexin43 increased in the contact coculture group. The effect of contact in the coculture group was significantly weakened by heptanol. Conclusions: The results suggested that gap junctions play an important role in the generation of SMCs from BMSCs. The formation of SMCs can potentially be used to repair the sphincter muscle of patients with stress urinary incontinence.

Mechanisms of polystyrene microplastic degradation by the microbially driven Fenton reaction.

Natural hydroxyl radical (·OH) production, which partially occurs through the microbially driven Fenton reaction, can enhance the degradation of polystyrene microplastics (PS-MPs). However, ·OH causes damage to microorganisms, which might in turn restrain the microbially driven Fenton reaction. Thus, whether PS-MPs can be continuously degraded by the microbially driven Fenton reaction and how they are degraded are still unknown. A pure-culture system using Shewanella putrefaciens 200 was set up to explore the effect and mechanism of microbially driven Fenton reaction on PS-MP degradation. In a 14-day operation, ·OH produced by the microbially driven Fenton reaction could degrade PS-MPs with a weight loss of 6.1 ± 0.6% and an O/C ratio of 0.6 (v.s. 0.6 ± 0.1% and 0.1, respectively, in the ·OH quenched group). Benzene ring derivatives such as 2-isopropyl-5-methyl-1-heptanol and nonahexacontanoic acid were the main soluble products of PS-MP degradation. The ·OH-induced oxidative damage on microorganisms did not affect ·OH production significantly when there was timely replenishment of organic carbon sources to promote reproduction of microorganisms. Thus, PS-MPs can be continuously degraded by microbially driven Fenton reactions in natural alternating anaerobic-aerobic environments. This study also provides a new microbial technique for MP degradation that is different from previous technologies based on microbial plastic-degrading enzymes.

Human epidermal in vitro permeation test (IVPT) analyses of alcohols and steroids.

This study examined a number of factors that can impact the outcomes of in vitro human epidermal permeation coefficients for aliphatic alcohols and steroids, including receptor phase composition and study conditions. We determined experimentally the solubilities and IVPT permeation of a homologous series of 14C labeled aliphatic alcohols (ethanol, propanol, pentanol, heptanol, octanol and decanol) in different receptor fluids as recommended by Organisation Economic Co-operation and Development (OECD). We used human epidermal membranes at 25 °C and phosphate-buffered saline (PBS), 2 %w/v bovine serum albumin (2 %w/v BSA), 50 %w/v ethanol and 0.1, 2 and 6 %w/v Oleth-20 receptor phases. We also explored and confirmed the discrepancies between in vitro human epidermal permeability coefficients (kp) and diffusion lag times for steroids from Scheuplein's group with our own work and that of others. The main reason for the observed differences is not clear but is likely to be multifactorial, including the effects of diffusion cell design, receptor phase solubility, unstirred receptor phase effects, epidermal membrane hydration, diffusion cell configuration, transport through appendageal pathways and steroid lipophilicity. We conclude with a summary of experimental conditions that should be considered in undertaking IVPT studies.

Anesthetics and Cell-Cell Communication: Potential Ca2+-Calmodulin Role in Gap Junction Channel Gating by Heptanol, Halothane and Isoflurane.

Cell-cell communication via gap junction channels is known to be inhibited by the anesthetics heptanol, halothane and isoflurane; however, despite numerous studies, the mechanism of gap junction channel gating by anesthetics is still poorly understood. In the early nineties, we reported that gating by anesthetics is strongly potentiated by caffeine and theophylline and inhibited by 4-Aminopyridine. Neither Ca2+ channel blockers nor 3-isobutyl-1-methylxanthine (IBMX), forskolin, CPT-cAMP, 8Br-cGMP, adenosine, phorbol ester or H7 had significant effects on gating by anesthetics. In our publication, we concluded that neither cytosolic Ca2+i nor pHi were involved, and suggested a direct effect of anesthetics on gap junction channel proteins. However, while a direct effect cannot be excluded, based on the potentiating effect of caffeine and theophylline added to anesthetics and data published over the past three decades, we are now reconsidering our earlier interpretation and propose an alternative hypothesis that uncoupling by heptanol, halothane and isoflurane may actually result from a rise in cytosolic Ca2+ concentration ([Ca2+]i) and consequential activation of calmodulin linked to gap junction proteins.

The lipoxygenase gene OsRCI-1 is involved in the biosynthesis of herbivore-induced JAs and regulates plant defense and growth in rice.

The pathway mediated by jasmonic acid (JA), biosynthesized via 13-lipoxygenases (LOX), plays a central role in both plant development and defense. In rice, there are at least fourteen 13-LOXs. Yet, only two 13-LOXs have been known to be involved in the biosynthesis of JA and plant defenses in rice. Here we cloned a chloroplast-localized 13-LOX gene from rice, OsRCI-1, whose transcripts were upregulated following infestation by brown planthopper (BPH, Nilaparvata lugens), one of the most important pests in rice. Overexpression of OsRCI-1 (oeRCI lines) increased levels of BPH-induced JA, jasmonate-isoleucine, trypsin protease inhibitors and three volatile compounds, 2-heptanone, 2-heptanol and α-thujene. BPHs showed a decreased colonization, fecundity and mass, and developed slowly on oeRCI plants compared with wild-type (WT) plants. Moreover, BPH-infested oeRCI plants were more attractive to the egg parasitoid of BPH, Anagrus nilaparvatae than equally treated WT plants. The decreased attractiveness to BPH and enhanced attractiveness to the parasitoid of oeRCI plants correlated with higher levels of BPH-induced 2-heptanone and 2-heptanol, and 2-heptanone, respectively. Compared with oeRCI plants, WT plants had higher plant height and 1000-grain weight. These results indicate that OsRCI-1 is involved in herbivore-induced JA bursts and plays a role in plant defense and growth.

Heptanol-mediated phase separation determines phase preference of molecules in live cell membranes.

The localization of many membrane proteins within cholesterol- and sphingolipid-containing microdomains is essential for proper cell signaling and function. These membrane domains, however, are too small and dynamic to be recorded, even with modern super-resolution techniques. Therefore, the association of membrane proteins with these domains can only be detected with biochemical assays that destroy the integrity of cells require pooling of many cells and take a long time to perform. Here, we present a simple membrane fluidizer-induced clustering approach to identify the phase-preference of membrane-associated molecules in individual live cells within 10-15 min. Experiments in phase-separated bilayers and live cells on molecules with known phase preference show that heptanol hyperfluidizes the membrane and stabilizes phase separation. This results in a transition from nanosized to micronsized clusters of associated molecules allowing their identification using routine microscopy techniques. Membrane fluidizer-induced clustering is an inexpensive and easy to implement method that can be conducted at large-scale and allows easy identification of protein partitioning in live cell membranes.

Configurations and Sensory Properties of the Stereoisomers of 2,6-Dimethyl-4-propyl-1,3-oxathiane and 2,4-Dimethyl-6-propyl-1,3-oxathiane.

The heterocyclic compounds 2,6-dimethyl-4-propyl-1,3-oxathiane 1 and 2,4-dimethyl-6-propyl-1,3-oxathiane 2 were obtained by condensing 4-mercapto-2-heptanol and 2-mercapto-4-heptanol, respectively, with acetaldehyde. For both, separation of the eight stereoisomers was achieved via capillary gas chromatography using heptakis(diethyl-tert-butyldimethylsilyl)-ß-cyclodextrin as the chiral stationary phase. Their configurations were assigned by combinations of enzyme-catalyzed kinetic resolutions, HPLC separations, and assessments of NMR data. The odor thresholds and odor qualities of the stereoisomers were determined by capillary gas chromatography/olfactometry. The odor thresholds of the stereoisomers of 2 were generally higher than those of 1. For both oxathianes, the stereoisomers in which all substituents are in equatorial positions showed the highest odor thresholds. Most of the stereoisomers of 1 exhibited pleasant flowery, fruity, or sweet nuances; the stereoisomers of 2 were mainly characterized by descriptors, such as broth, mushroom, or pungent. The data demonstrate the impact of the positions of substituents and their spatial orientations on the sensory properties of 1,3-oxathianes.