Salt Tolerance Assessment in Triticum Aestivum and Triticum Durum

BACKGROUND

Salt stress is a multicomponent phenomenon; it includes many processes that directly or indirectly affect the plant. Attempts have been made to comprehensively consider the processes of salt stress in plants Triticum aestivum (variety Orenburgskaya 22) and Triticum durum (variety Zolotaya).

METHODS

The study used methods of light and fluorescence microscopy, methods of immunofluorodetection, expression of DNA methyltransferase genes, genes of the ion transporter and superoxide dismutase families, as well as biochemical determination of total antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent.

RESULTS

According to morphometric indicators, the Orenburgskaya 22 variety showed greater tolerance to the action of 150 mM NaCl than the Zolotaya variety. The level of expression of genes of the HKT ion transporter family in the Orenburgskaya 22 variety is higher than in the Zolotaya variety. It was found that the expression of the DNA methyltransferase gene DRM2.1, which post-translationally methylates cytosine residues, is 22.3 times higher in Zolotaya compared to Orenburg 22 when exposed to salt. The accumulation of toxic ions is accompanied by an increase in reactive oxygen species (ROS) and increased damage to root tissue, especially in the Zolotaya variety. Using fluorescence microscopy using the Carboxy-H2DFF marker in the Orenburgskaya 22 variety at high NaCl concentrations, the highest fluorescence intensity was determined in the cap zone; in the Zolotaya variety-in the zones of the cap and root meristem. Excess ROS is more successfully removed in the Orenburgskaya 22 variety, which has a higher level of antioxidant activity (AOA), as well as the level of expression of the Cu/ZnSOD and MnSOD superoxide dismutase genes. Using programmed cell death (PCD) markers based on the release of cytochrome c from mitochondria into the cytoplasm, DNA breakage and the release of phosphatidylserine from mitochondria, the degree of damage to root cells was assessed in both wheat varieties. It has been proven that wheat cell death occurs through the mitochondrial pathway. It was noted that the salt-sensitive variety Zolotaya had a significant number of necrotic cells.

CONCLUSION

Based on the data obtained, it was concluded that the Orenburgskaya 22 variety exhibits greater resistance to salinity than the Zolotaya variety. These data may be of practical importance for enhancing protective mechanisms under abiotic stress.

ALLENE OXIDE SYNTHASE (AOS) induces petal senescence through a novel JA-associated regulatory pathway in Arabidopsis

Flowers are crucial for the reproduction of flowering plants and their senescence has drastic effects on plant-animal interactions as well as pollination. Petal senescence is the final phase of flower development which is regulated by hormones and genes. Among these, jasmonic acid (JA) has emerged as a major contributor to petal senescence, but its molecular mechanisms remain elusive. Here, the role of JA in petal senescence in Arabidopsis was investigated. We showed that petal senescence in aos mutant was significantly delayed, which also affected petal cell size and proliferation. Similar significant delays in petal senescence were observed in dad1 and coi1 mutants. However, MYB21/24 and MYC2/3/4, known downstream regulators of JA in flower development, played no role in petal senescence. This indicated that JA regulates petal senescence by modulating other unknown transcription factors. Transcriptomic analysis revealed that AOS altered the expression of 3681 genes associated, and identified groups of differentially expressed transcription factors, highlighting the potential involvement of AP-2, WRKY and NAC. Furthermore, bHLH13, bHLH17 and URH2 were identified as potential new regulators of JA-mediated petal senescence. In conclusion, our findings suggest a novel genetic pathway through which JA regulates petal senescence in Arabidopsis. This pathway operates independently of stamen development and leaf senescence, suggesting the evolution of specialized mechanisms for petal senescence.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01425-w.

Mechanisms of Antioxidant Resistance in Different Wheat Genotypes under Salt Stress and Hypoxia

Various stressors lead to an increase in ROS and damage to plant tissues. Plants have a powerful antioxidant system (AOS), which allows them to neutralize excess ROS. We detected an intense fluorescent glow of ROS in the cells of the cap, meristem, and elongation zones in the roots of wheat Triticum aestivum (Orenburgskaya 22 variety) and Triticum durum (Zolotaya variety). An increase in ROS was accompanied by DNA breaks in the nuclei of wheat root cells, the release of cytochrome c from mitochondria into the cytoplasm, and the translocation of phosphatidylserine into the outer layer of the plasma membrane under salt stress and hypoxia. The different resistances of the two wheat varieties to different abiotic stresses were revealed. The soft wheat variety Orenburgskaya 22 showed high resistance to salt stress but sensitivity to hypoxia, and the durum wheat variety Zolotaya showed tolerance to hypoxia but high sensitivity to salt stress. Different activations of AOS components (GSH, MnSOD, Cu/ZnSOD, CAT, PX, GPX, and GST) were revealed in different wheat genotypes. The basis for the tolerance of the Zolotaya variety to hypoxia is the high content of glutathione (GSH) and the activation of glutathione-dependent enzymes. One of the mechanisms of high resistance to salt stress in the Orenburgskaya 22 variety is a decrease in the level of ROS as a result of the increased activity of the MnSOD and Cu/ZnSOD genes. Identifying the mechanisms of plant tolerance to abiotic stress is the most important task for improving breeding varieties of agricultural plants and increasing their yield.

Protective Effects of Alginate and Chitosan Oligosaccharides against Clostridioides difficile Bacteria and Toxin

Clostridioides difficile infection is expected to become the most common healthcare-associated infection worldwide. C. difficile-induced pathogenicity is significantly attributed to its enterotoxin, TcdA, which primarily targets Rho-GTPases involved in regulating cytoskeletal and tight junction (TJ) dynamics, thus leading to cytoskeleton breakdown and ultimately increased intestinal permeability. This study investigated whether two non-digestible oligosaccharides (NDOs), alginate (AOS) and chitosan (COS) oligosaccharides, possess antipathogenic and barrier-protective properties against C. difficile bacteria and TcdA toxin, respectively. Both NDOs significantly reduced C. difficile growth, while cell cytotoxicity assays demonstrated that neither COS nor AOS significantly attenuated the TcdA-induced cell death 24 h post-exposure. The challenge of Caco-2 monolayers with increasing TcdA concentrations increased paracellular permeability, as measured by TEER and LY flux assays. In this experimental setup, COS completely abolished, and AOS mitigated, the deleterious effects of TcdA on the monolayer's integrity. These events were not accompanied by alterations in ZO-1 and occludin protein levels; however, immunofluorescence microscopy revealed that both AOS and COS prevented the TcdA-induced occludin mislocalization. Finally, both NDOs accelerated TJ reassembly upon a calcium-switch assay. Overall, this study established the antipathogenic and barrier-protective capacity of AOS and COS against C. difficile and its toxin, TcdA, while revealing their ability to promote TJ reassembly in Caco-2 cells.

Alginate Oligosaccharides Repair Liver Injury by Improving Anti-Inflammatory Capacity in a Busulfan-Induced Mouse Model

Liver diseases are associated with many factors, including medicines and alcoholics, which have become a global problem. It is crucial to overcome this problem. Liver diseases always come with inflammatory complications, which might be a potential target to deal with this issue. Alginate oligosaccharides (AOS) have been demonstrated to have many beneficial effects, especially anti-inflammation. In this study, 40 mg/kg body weight (BW) of busulfan was intraperitoneally injected once, and then the mice were dosed with ddH₂O or AOS 10 mg/kg BW every day by oral gavage for five weeks. We investigated AOS as a potential no-side-effect and low-cost therapy for liver diseases. For the first time, we discovered that AOS 10 mg/kg recovered liver injury by decreasing the inflammation-related factors. Moreover, AOS 10 mg/kg could improve the blood metabolites related to immune and anti-tumor effects, and thus, ameliorated impaired liver function. The results indicate that AOS may be a potential therapy to deal with liver damage, especially in inflammatory conditions.

Safety of tongue base procedures for sleep apnoea in adults: A systematic review and metanalysis from the YO-IFOS study group

OBJECTIVE

Tongue base and hypopharynx are the major sites of obstruction in OSA patients with failed palatal surgery. In recent years, several minimally invasive procedures have been developed to address tongue base obstruction. However, the research focus has consistently been on the effectiveness of surgery in reducing obstructive sleep apnoea rather than on postoperative complications. In this systematic review and metanalysis we aim to review the complication rate of minimally invasive base of tongue procedures for OSAS in adults.

DATA SOURCES

PubMed (Medline), the Cochrane Library, EMBASE, Scopus, SciELO and Trip Database.

REVIEW METHODS

Data sources were checked by three authors of the YO-IFOS sleep apnoea study group. Three authors extracted the data. Main outcome was expressed as the complication rate and 95% confidence interval for each surgical technique.

RESULTS

20 studies (542 patients) met the inclusion criteria. The mean complication rate is 12.79%; 4.65% for minor complications, 6.42% if they are moderate, and 1.77% if severe. The most reported complication overall is infection, in 1.95% of cases, followed by transient swallowing disorder, occurring in 1.30% of the total sample.

CONCLUSION

The heterogeneity amongst the included studies prevents us from obtaining solid conclusions. The available evidence suggests that minimally invasive base of tongue procedures may present a wide spectrum of complication rates, ranging from 4.4% in tongue base radiofrequency to up to 42.42% in tongue base ablation.

Gut Microbiota-Testis Axis: FMT Mitigates High-Fat Diet-Diminished Male Fertility via Improving Systemic and Testicular Metabolome

High-fat diet (HFD)-induced obesity is known to be associated with reduced male fertility and decreased semen quality in humans. HFD-related male infertility is a growing issue worldwide, and it is crucial to overcome this problem to ameliorate the distress of infertile couples. For the first time, we discovered that fecal microbiota transplantation (FMT) of alginate oligosaccharide (AOS)-improved gut microbiota (A10-FMT) ameliorated HFD-decreased semen quality (sperm concentration: 286.1 ± 14.1 versus 217.9 ± 17.4 million/mL; sperm motility: 40.1 ± 0.7% versus 29.0 ± 0.9%), and male fertility (pregnancy rate: 87.4 ± 1.1% versus 70.2 ± 6.1%) by benefiting blood and testicular metabolome. A10-FMT improved HFD-disturbed gut microbiota by increasing gut Bacteroides (colon: 24.9 ± 1.1% versus 8.3 ± 0.6%; cecum: 10.2 ± 0.7% versus 3.6 ± 0.7%) and decreasing Mucispirillum (colon: 0.3 ± 0.1% versus 2.8 ± 0.4%; cecum: 2.3 ± 0.5% versus 6.6 ± 0.7%). A10-FMT benefited gut microbiota to improve liver function by adjusting lipid metabolism to produce n-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (blood: 55.5 ± 18.7 versus 20.3 ± 2.4) and docosahexaenoic acid (testis: 121.2 ± 6.2 versus 89.4 ± 6.7), thus ameliorating HFD-impaired testicular microenvironment to rescue spermatogenesis and increase semen quality and fertility. The findings indicated that AOS-improved gut microbiota may be a promising strategy to treat obesity or metabolic issues-related male infertility in the future. IMPORTANCE HFD decreases male fertility via upsetting gut microbiota and transplantation of AOS-benefited gut microbiota (A10-FMT) improves gut microbiota to ameliorate HFD-reduced male fertility. Moreover, A10-FMT improved liver function to benefit the blood metabolome and simultaneously ameliorated the testicular microenvironment to turn the spermatogenesis process on. We demonstrated that AOS-benefited gut microbiota could be applied to treat infertile males with obesity and metabolic issues induced by HFD.

Hard-to-heal ulcers treated with hypochlorous acid oxidising solution and standard of care: a 32-week follow-up

OBJECTIVE

Immediately following a two-year prospective case series in which the wounds of 60 patients with hard-to-heal ulcers were treated with a hypochlorous acid oxidising solution (AOS) in addition to standard of care (SoC) for 70 days (T0-T70), a subset of 31 patients (51.7%) whose wounds had not fully healed by T70 opted to continue with treatment for a further 22 weeks (days T70-T224, a total treatment time of 32 weeks (224 days). The objective was to provide long-term evidence on the clinical performance and safety of AOS when used in association with the usual SoC in patients with stalled, hard-to-heal ulcers of various aetiologies.

METHOD

As per the main study, wounds were formally assessed by the study lead at 28 days (±14 days, depending on patient attendance). Parameters assessed at fortnightly visits included area, depth and duration of ulcer; pain; wound bed preparation (WBP) score; and infection status. Wounds were managed in accordance with the SoC protocol.

RESULTS

By T224, 35.5% (n=11) of wounds healed completely and 83.9% showed some types of improvement. All wounds were free of infection and colonisation, the WBP score improved (100% A1-A2 at T196), and pain scores fell. Use of AOS in combination with several types of dressing (SoC) for such a long period confirmed a good safety profile.

CONCLUSION

This follow-up evaluation, coupled with the primary study, suggests that AOS might represent a valuable therapeutic addition for the management of hard-to-heal ulcers for long periods of treatment.

DECLARATION OF INTEREST

ER worked as a consultant for APR Applied Pharma Research S.A. The authors have no other conflicts of interest.

Wound bed preparation with hypochlorous acid oxidising solution and standard of care: a prospective case series

OBJECTIVE

This prospective case series aims to evaluate the clinical impact of a hypochlorous acid oxidising solution (AOS) in association with usual standard of care (SoC) on wound bed preparation (WBP) in patients with hard-to-heal ulcers of various aetiologies. The AOS (Nexodyn, APR Applied Pharma Research S.A., Switzerland) comprises three main features: highly pure and stabilised hypochlorous acid, acidic pH and high reduction-oxidation potential.

METHOD

Between February 2015 and February 2017, patients who met the inclusion criteria were treated with AOS and usual SoC. Data collection ran for 70 days: T0-T70. A baseline assessment was undertaken at T0; parameters assessed at fortnightly visits included: WBP score, area and depth of ulcer, duration, pain, Bates-Jensen score and infection status.

RESULTS

A total of 60 patients took part in the study. By T70, 68.3% of wounds had healed or improved and a significant wound size reduction of 21% was observed (p<0.001), despite a mean wound duration of 20.6 months. All wounds were free of local infection and cellulitis; 10% were colonised. WBP scores improved, while Bates-Jensen and pain scores fell significantly over time.

CONCLUSION

This evaluation suggests that AOS might represent a valuable therapeutic addition for an optimal WBP in the routine management of hard-to-heal ulcers of different aetiologies.

DECLARATION OF INTEREST

ER worked as a consultant for APR Applied Pharma Research S.A. The authors have no other conflicts of interest.

Management of hard-to-heal leg ulcers with an acid-oxidising solution versus standard of care: the MACAN study

OBJECTIVE

The efficacy of available wound dressings in the treatment of hard-to-heal wounds is limited. A new therapeutic approach using an acid-oxidising solution (AOS) was developed. Its effect on healing progress, tolerability and safety properties were investigated in a clinical study, and compared with standard of care (SOC) wound dressings. The study aimed to demonstrate the non-inferiority of AOS to SOC in terms of wound healing progress.

METHOD

This open-label, randomised controlled trial was conducted at two study centres in Austria with patients with either infected or non-infected hard-to-heal leg ulcers of different aetiology. Patients were treated for six weeks either with AOS or SOC wound dressings. Outcome assessments included the percentage of granulation and re-epithelialisation tissue, wound size reduction, changes in wound pH, infection control and wound pain, local tolerability and adverse events (AEs). Healing time and rate were also assessed.

RESULTS

A total of 50 patients took part. In the AOS group, wounds exhibited higher amounts of granulation and re-epithelialisation tissue, and a faster and more pronounced wound size reduction compared with wounds in the SOC group. In the AOS-treated versus SOC-treated patients, a greater percentage of complete healing of hard-to-heal ulcers was achieved by the end of the study period (32% versus 8%, respectively). Furthermore, the wound pH decreased significantly faster in these wounds (p<0.0001). In all patients with infected leg ulcers, local infection was overcome more rapidly under AOS treatment. In the AOS group, one AE and no serious adverse events (SAEs) were detected versus 24 AEs and two SAEs in the SOC group.

CONCLUSION

In this study, AOS proved to be a highly effective treatment to support wound healing in infected or non-infected hard-to-heal leg ulcers of different aetiology. Efficacy was found to be not only non-inferior but superior to SOC wound dressings. Furthermore, tolerability and safety profiles were favourable for AOS.

Hydroperoxide lyase modulates defense response and confers lesion-mimic leaf phenotype in soybean (Glycine max (L.) Merr.)

Allene oxide synthase (AOS) and hydroperoxide lyase (HPL) are two important members of P450 enzymes metabolizing hydroperoxy fatty acid to produce jasmonates and aldehydes respectively, which function in response to diverse environmental and developmental stimuli. However, their exact roles in soybean have not been clarified. In present study, we identified a lesion-mimic mutant in soybean named NT302, which exhibits etiolated phenotype together with chlorotic and spontaneous lesions on leaves at R3 podding stage. The underlying gene was identified as GmHPL encoding hydroperoxide lyase by map-based cloning strategy. Sequence analysis demonstrated that a single nucleotide mutation created a premature termination codon (Gln20-Ter), which resulted in a truncated GmHPL protein in NT302. GmHPL RNA was significantly reduced in NT302 mutant, while genes in AOS branch of the 13-LOX pathway were up-regulated in NT302. The mutant exhibited higher susceptibility to bacterial leaf pustule (BLP) disease, but increased resistance against common cutworm (CCW) pest. GmHPL was significantly induced in response to MeJA, wounding, and CCW in wild type soybean. Virus induced gene silencing (VIGS) of GhHPL genes gave rise to similar lesion-mimic leaf phenotypes in upland cotton, coupled with upregulation of the expression of JA biosynthesis and JA-induced genes. Our study provides evidence that competition exist between HPL and AOS branches in 13-LOX pathway of the oxylipin metabolism in soybean, thereby plays essential roles in modulation of plant development and defense.

Pure Apraxia of Speech After Resection Based in the Posterior Middle Frontal Gyrus

BACKGROUND AND IMPORTANCE

Apraxia of speech is a disorder of articulatory coordination and planning in speech sound production. Its diagnosis is based on deficits in articulation, prosody, and fluency. It is often described concurrent with aphasia or dysarthria, while pure apraxia of speech is a rare entity.

CLINICAL PRESENTATION

A right-handed man underwent focal surgical resection of a recurrent grade III astrocytoma in the left hemisphere dorsal premotor cortex located in the posterior middle frontal gyrus. After the procedure, he experienced significant long-term speech production difficulties. A battery of standard and custom language and articulatory assessments were administered, revealing intact comprehension and naming abilities, and preserved strength in orofacial articulators, but considerable deficits in articulatory coordination, fluency, and prosody-consistent with diagnosis of pure apraxia of speech. Tractography and resection volumes compared with publicly available imaging data from the Human Connectome Project suggest possible overlap with area 55b, an under-recognized language area in the dorsal premotor cortex and has white matter connectivity with the superior longitudinal fasciculus.

CONCLUSION

The case reported here details a rare clinical entity, pure apraxia of speech resulting from resection of posterior middle frontal gyrus. While not a classical language area, emerging literature supports the role of this area in the production of fluent speech, and has implications for surgical planning and the general neurobiology of language.

Alginate oligosaccharides improve germ cell development and testicular microenvironment to rescue busulfan disrupted spermatogenesis

Rationale: Busulfan is currently an indispensable anti-cancer drug, particularly for children, but the side effects on male reproduction are so serious that critical drug management is needed to minimize any negative impact. Meanwhile, alginate oligosaccharides (AOS) are natural products with many consequent advantages, that have attracted a great deal of pharmaceutical attention. In the current investigation, we performed single-cell RNA sequencing on murine testes treated with busulfan and/or AOS to define the mitigating effects of AOS on spermatogenesis at the single cell level.

Methods: Testicular cells (in vivo) were examined by single cell RNA sequencing analysis, histopathological analysis, immunofluorescence staining, and Western blotting. Testes samples (ex vivo) underwent RNA sequencing analysis. Blood and testicular metabolomes were determined by liquid chromatography-mass spectrometry (LC/MS).

Results: We found that AOS increased murine sperm concentration and motility, and rescued busulfan disrupted spermatogenesis through improving (i) the proportion of germ cells, (ii) gene expression important for spermatogenesis, and (iii) transcriptional factors in vivo. Furthermore, AOS promoted the ex vivo expression of genes important for spermatogenesis. Finally, our results showed that AOS improved blood and testis metabolomes as well as the gut microbiota to support the recovery of spermatogenesis.

Conclusions: AOS could be used to improve fertility in patients undergoing chemotherapy and to combat other factors that induce infertility in humans.

Temperature Dependence Of AOS Thin Film Nano Transistors For Medical Applications

Background

A novel temperature dependent amorphous nano oxide semiconductor (AOS) thin-film transistor (TFT) is reported here for the first time, which is vastly different from conventional behavior. In the literature, the threshold voltage of TFTs decreases with increasing temperature. Here, the threshold voltage increased at higher temperatures, which is different from previously reported results and was repeated on different samples.

Methods

Electrical experiments (such as I-V measurements and photoelectron spectrometer experiments) were performed in order to explain such behavior. Double sweeping gate voltage measurements were performed to investigate the mechanism for the temperature dependent behavior.

Results

It was found that there was a change of trap charge under thermal stress, which was released after the stress.

Conclusion

Non-Arrhenius behaviors (including a linear behavior) were obtained for the amorphous nano oxide thin-film transistors within 303~425 K, suggesting their potential to be adjusted by measurement processes and be applied as temperature sensors for numerous medical applications.

Identification of Jasmonic Acid and Jasmonoyl-Isoleucine, and Characterization of AOS, AOC, OPR and JAR1 in the Model Lycophyte Selaginella moellendorffii

Jasmonic acid (JA) is involved in a variety of physiological responses in seed plants. However, the detection and role of JA in lycophytes, a group of seedless vascular plants, have remained elusive until recently. This study provides the first evidence of 12-oxo-phytodienoic acid (OPDA), JA and jasmonoyl-isoleucine (JA-Ile) in the model lycophyte Selaginella moellendorffii. Mechanical wounding stimulated the accumulation of OPDA, JA and JA-Ile. These data were corroborated by the detection of enzymatically active allene oxide synthase (AOS), allene oxide cyclase (AOC), 12-oxo-phytodienoic acid reductase 3 (OPR3) and JA-Ile synthase (JAR1) in S. moellendorffii. SmAOS2 is involved in the first committed step of JA biosynthesis. SmAOC1 is a crucial enzyme for generating the basic structure of jasmonates and is actively involved in the formation of OPDA. SmOPR5, a functionally active OPR3-like enzyme, is also vital for the reduction of (+)-cis-OPDA, the only isomer of the JA precursor. The conjugation of JA to Ile by SmJAR1 demonstrates that S. moellendorffii produces JA-Ile. Thus, the four active enzymes have characteristics similar to those in seed plants. Wounding and JA treatment induced the expression of SmAOC1 and SmOPR5. Furthermore, JA inhibited the growth of shoots in S. moellendorffii, which suggests that JA functions as a signaling molecule in S. moellendorffii. This study proposes that JA evolved as a plant hormone for stress adaptation, beginning with the emergence of vascular plants.

Insights on germinability and desiccation tolerance in developing neem seeds (Azadirachta indica): Role of AOS, antioxidative enzymes and dehydrin-like protein

The germinability and desiccation tolerance (DT) in developing seed are regulated by cellular metabolism involving active oxygen species (AOS) and protective proteins during maturation drying. The aim of the present investigation was to unravel the functions of AOS (superoxide, H₂O₂ and OH-radical), antioxidative enzymes (SOD, CAT and APX) and dehydrin-like proteins in regulating the germinability and DT in undried and artificially desiccated developing neem seeds. Germination was first observed in seeds of 8 weeks after anthesis (waa) whereas DT was noticed from 9 waa. High levels of superoxide in undried and artificially desiccated seeds of 9 waa were rapidly declined up to 15 waa with simultaneous increase in levels of SOD (quantitative and isoenzymes) that dismutates superoxide with corresponding formation and accumulation of H₂O₂. Activities and isoenzymes of APX and CAT were promoted in seeds from 9 to 12 waa. Intensity of dehydrin-like proteins increased as development progressed in seeds with higher intensities in slow dried (SD) seeds. Desiccation modulated the metabolism for the acquisition of germinability and DT in the developing neem seeds from 8 to 15 waa by altering the levels of superoxide, H₂O₂ and OH-radical those possibly act as signalling molecules for reprogramming protective proteins. Desiccation mediated the expression of new bands of SOD and APX in undried as well as SD seeds during 9-12 waa but the bands were more intense in SD seeds. The superoxide and H₂O₂-regulated intensity of dehydrin-like protein in SD seeds further validated our conclusion.

A systematic study of the whole genome sequence of Amycolatopsis methanolica strain 239T provides an insight into its physiological and taxonomic properties which correlate with its position in the genus

The complete genome of methanol-utilizing Amycolatopsis methanolica strain 239^T was generated, revealing a single 7,237,391 nucleotide circular chromosome with 7074 annotated protein-coding sequences (CDSs). Comparative analyses against the complete genome sequences of Amycolatopsis japonica strain MG417-CF17^T, Amycolatopsis mediterranei strain U32 and Amycolatopsis orientalis strain HCCB10007 revealed a broad spectrum of genomic structures, including various genome sizes, core/quasi-core/non-core configurations and different kinds of episomes. Although polyketide synthase gene clusters were absent from the A. methanolica genome, 12 gene clusters related to the biosynthesis of other specialized (secondary) metabolites were identified. Complete pathways attributable to the facultative methylotrophic physiology of A. methanolica strain 239^T, including both the mdo/mscR encoded methanol oxidation and the hps/hpi encoded formaldehyde assimilation via the ribulose monophosphate cycle, were identified together with evidence that the latter might be the result of horizontal gene transfer. Phylogenetic analyses based on 16S rDNA or orthologues of AMETH_3452, a novel actinobacterial class-specific conserved gene against 62 or 18 Amycolatopsis type strains, respectively, revealed three major phyletic lineages, namely the mesophilic or moderately thermophilic A. orientalis subclade (AOS), the mesophilic Amycolatopsis taiwanensis subclade (ATS) and the thermophilic A. methanolica subclade (AMS). The distinct growth temperatures of members of the subclades correlated with corresponding genetic variations in their encoded compatible solutes. This study shows the value of integrating conventional taxonomic with whole genome sequence data.

DOCK6 mutations are responsible for a distinct autosomal-recessive variant of Adams-Oliver syndrome associated with brain and eye anomalies

Adams-Oliver syndrome (AOS) is characterized by the association of aplasia cutis congenita with terminal transverse limb defects, often accompanied by additional cardiovascular or neurological features. Both autosomal-dominant and autosomal-recessive disease transmission have been observed, with recent gene discoveries indicating extensive genetic heterogeneity. Mutations of the DOCK6 gene were first described in autosomal-recessive cases of AOS and only five DOCK6-related families have been reported to date. Recently, a second type of autosomal-recessive AOS has been attributed to EOGT mutations in three consanguineous families. Here, we describe the identification of 13 DOCK6 mutations, the majority of which are novel, across 10 unrelated individuals from a large cohort comprising 47 sporadic cases and 31 AOS pedigrees suggestive of autosomal-recessive inheritance. DOCK6 mutations were strongly associated with structural brain abnormalities, ocular anomalies, and intellectual disability, thus suggesting that DOCK6-linked disease represents a variant of AOS with a particularly poor prognosis.

Mechanistic insights into the catalytic reaction of plant allene oxide synthase (pAOS) via QM and QM/MM calculations

QM cluster and QM/MM protein models have been employed to understand aspects of the reaction mechanism of plant allene oxide synthase (pAOS). In this study we have investigated two reaction mechanisms for pAOS. The standard pAOS mechanism was contrasted with an alternative involving an additional active site molecule which has been shown to facilitate proton coupled electron transfer (PCET) in related systems. Firstly, we found that the results from QM/MM protein model are comparable with those from the QM cluster model, presumably due to the large active site used. Furthermore, the results from the QM cluster model show that the Fe(III) and Fe(IV) pathways for the standard mechanism have similar energetic and structural properties, indicating that the reaction mechanism may well proceed via both pathways. However, while the PCET process is facilitated by an additional active site bound water in other related families, in pAOS it is not, suggesting this type of process is not general to all closely related family members.

Nitric oxide mediates alginate oligosaccharides-induced root development in wheat (Triticum aestivum L.)

Alginate oligosaccharides (AOS), which are marine oligosaccharides, are involved in regulating plant root growth, but the promotion mechanism for AOS remains unclear. Here, AOS (10-80 mg L(-1)) were found to induce the generation of nitric oxide (NO) in the root system of wheat (Triticum aestivum L.), which promoted the formation and elongation of wheat roots in a dose-dependent manner. NO inhibitors suggested that nitrate reductase (NR), rather than nitric oxide synthase (NOS), was essential for AOS-induced root development. Further studies confirmed that AOS-induced NO generation in wheat roots by up-regulating the gene expression and enzyme activity of NR at the post-transcriptional level. The anatomy and RT-PCR results showed that AOS accelerated the division and growth of stele cells, leading to an increase in the ratio of stele area to root transverse area. This could be inhibited by the NR inhibitor, sodium tungstate, which indicated that NO catalyzed by the NR was involved in AOS regulation of root development. Taken together, in the early stage of AOS-induced root development, NO generation was a novel mechanism by which AOS regulated plant growth. The results also showed that this marine resource could be widely used for crop development.

Differences in the arbuscular mycorrhizal fungi-improved rice resistance to low temperature at two N levels: aspects of N and C metabolism on the plant side

We performed an experiment to determine how N and C metabolism is involved in the low-temperature tolerance of mycorrhizal rice (Oryza sativa) at different N levels and examined the possible signaling molecules involved in the stress response of mycorrhizal rice. Pot cultures were performed, and mycorrhizal rice growth was evaluated based on treatments at two temperatures (15 °C and 25 °C) and two N levels (20 mg pot(-1) and 50 mg pot(-1)). The arbuscular mycorrhizal fungi (AMF) colonization of rice resulted in different responses of the plants to low and high N levels. The mycorrhizal rice with the low N supplementation had more positive feedback from the symbiotic AMF, as indicated by accelerated N and C metabolism of rice possibly involving jasmonic acid (JA) and the up-regulation of enzyme activities for N and C metabolism. Furthermore, the response of the mycorrhizal rice plants to low temperature was associated with P uptake and nitric oxide (NO).

Glutathione S-transferase (GST) family in barley: identification of members, enzyme activity, and gene expression pattern

Barley (Hordeum vulgare) is one of the most important cereals in many developing countries where drought stress considerably diminishes agricultural production. Glutathione S-transferases (GSTs EC 2.5.1.18) are multifunctional enzymes which play a crucial role in cellular detoxification and oxidative stress tolerance. In this study, 84 GST genes were identified in barley by a comprehensive in silico approach. Sequence alignment and phylogenetic analysis grouped these HvGST proteins in eight classes. The largest numbers of the HvGST genes (50) were included in the Tau class followed by 21 genes in Phi, five in Zeta, two in DHAR, two in EF1G, two in Lambda, and one each in TCHQD and Theta classes. Phylogenetic analysis of the putative GSTs from Arabidopsis, rice, and barley indicated that major functional diversification within the GST family predated the monocot/dicot divergence. However, intra-specious duplication seems to be common. Expression patterns of five GST genes from Phi and Tau classes were investigated in three barley genotypes (Yusof [drought-tolerant], Moroc9-75 [drought-sensitive], and HS1 [wild ecotype]) under control and drought-stressed conditions, during the vegetative stage. All investigated genes were up-regulated significantly under drought stress and/or showed a higher level of transcripts in the tolerant cultivar. Additionally, GST enzyme activity was superior in Yusof and induced in the extreme-drought-treated leaves, while it was not changed in Moroc9-75 under drought conditions. Moreover, the lowest and highest levels of lipid peroxidation were observed in the Yusof and Moroc9-75 cultivars, respectively. Based on the achieved results, detoxification and antioxidant activity of GSTs might be considered an important factor in the drought tolerance of barley genotypes for further investigations.

Thermal conversions of fatty acid peroxides to cyclopentenones: a biomimetic model for allene oxide synthase pathway

The trimethylsilyl (TMS) peroxides of linoleic acid 9(S)-hydroperoxide (TMS or Me esters) were subjected to gas chromatography-mass spectrometry (GC-MS) analyses. The cyclopentenones, trans- and cis-10-oxo-11-phytoenoic acid (10-oxo-PEA, Me or TMS esters) were first time detected as the products of TMS-peroxide thermal conversions. The major products were ketodienes, epoxyalcohols, hemiacetals and decadienals. For further study of thermal cyclopentenone formation, 9(S)- or 13(S)-hydroperoxides of linoleic acid (Me esters) were sealed in ampoules and heated at 230 °C for 15 or 30 min. The products were separated by HPLC. The cyclopentenone fractions were collected and analyzed by GC-MS. Trans-10-oxo-PEA (Me) and 10-oxo-9(13)-PEA (Me) were formed during the thermal conversion of 9-hydroperoxide (Me ester). Similarly, the cyclopentenones trans-12-oxo-PEA (Me) and 12-oxo-9(13)-PEA (Me) were detected after the heating of 13-hydroperoxide (Me ester). Thermal formation of cyclopentenones can be considered as a biomimetic model of AOS pathway, providing new insights into the mechanisms of allene oxide formation and cyclization.

Methyl jasmonate treatment induces changes in fruit ripening by modifying the expression of several ripening genes in Fragaria chiloensis fruit

To investigate the role of jasmonates (JAs) in the ripening of Fragaria chiloensis fruit, two concentrations of methyl jasmonate (MeJA, 10 and 100 μM) were evaluated at 2, 5 and 9 d using an in vitro ripening system. Fruit quality parameters; the contents of anthocyanin, lignin and cell wall polymers; and the transcriptional profiles of several ripening-related genes were analyzed. MeJA accelerated fruit ripening by means of a transitory increase in the soluble solid content/titratable acidity ratio, anthocyanin accumulation and an increase in softening at day 5. The expression of several phenylpropanoid-related genes, primarily those associated with anthocyanin biosynthesis, was increased under MeJA treatment, which correlated with an increased accumulation of anthocyanin. MeJA also altered the expression profiles of some cell wall-modifying genes, namely, EG1 and XTH1, and these changes correlated with a transient reduction in the firmness of MeJA-treated fruits. MeJA-responsive elements were observed in the promoter region of the EG1 gene. MeJA also increased the expression of LOX, AOS and OPR3, genes involved in the biosynthesis of JAs, and these changes correlated with the transient activation of fruit ripening observed. Conversely, the expression of ethylene and lignin biosynthesis genes (ACS, ACO, CAD and POD27) increased in MeJA-treated fruits at day 9. The present findings suggest that JAs promote the ripening of non-climacteric fruits through their involvement in anthocyanin accumulation, cell wall modification and the biosynthesis of ethylene and JAs.

Biochemical and physiological responses of oil palm to bud rot caused by Phytophthora palmivora

In recent years, global consumption of palm oil has increased significantly, reaching almost 43 million tons in 2010. The sustainability of oil palm (Elaeis guineensis) cultivation has been compromised because of the bud rot disease whose initial symptoms are caused by Phytophthora palmivora. There was a significant incidence of the disease, from an initial stage 1 of the disease to the highest stage 5, that affected photosynthetic parameters, content of pigments, sugars, polyamines, enzymatic antioxidant activities, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) and β-(1,3) glucanase (β-Gluc, EC 3.2.1.39). In healthy palms photosynthesis was 13.29 μmol CO2 m(-2) s(-1) in average, while in stage 5 the average photosynthesis was around 3.66 μmol CO2 m(-2) s(-1). Additionally, total chlorophyll was reduced by half at the last stage of the disease. On the contrary, the contents of putrescine, spermine and spermidine increased three, nine and twelve times with respect to stage 5, respectively. Antioxidant enzyme activities, as well as the phenylalanine ammonia-lyase and β-(1,3) glucanase showed an increase as the severity of the disease increased, with the latter increasing from 0.71 EAU in healthy palms to 2.60 EAU in plants at stage 5 of the disease. The peroxidase (POD, EC 1.11.1.7) enzymatic activity and the content of spermidine were the most sensitive indicators of disease.

Structure-function relationship in the CYP74 family: conversion of divinyl ether synthases into allene oxide synthases by site-directed mutagenesis

Non-classical P450s of CYP74 family control several enzymatic conversions of fatty acid hydroperoxides to bioactive oxylipins in plants, some invertebrates and bacteria. The family includes two dehydrases, namely allene oxide synthase (AOS) and divinyl ether synthase (DES), and two isomerases, hydroperoxide lyase (HPL) and epoxyalcohol synthase. To study the interconversion of different CYP74 enzymes, we prepared the mutant forms V379F and E292G of tobacco (CYP74D3) and flax (CYP74B16) divinyl ether synthases (DESs), respectively. In contrast to the wild type (WT) enzymes, both mutant forms lacked DES activity. Instead, they produced the typical AOS products, α-ketols and (in the case of the flax DES mutant) 12-oxo-10,15-phytodienoic acid. This is the first demonstration of DES into AOS conversions caused by single point mutations.