Production of volatile organic compounds by the yeast fungus Dipodascus aggregatus

Summary The yeast fungus Dipodascus aggregatus was grown aerobically in a synthetic nutrient solution and the volatile compounds produced were concentrated. Identification of the volatiles was performed by combined gas chromatographymass spectrometry or by one of these methods. The compounds identified were 11 esters, 9 alcohols, 5 acids and 3 carbonyls.The time course production of volatile neutral compounds was followed. During the phase of no apparent growth only a few substances were formed (mostly alcohols). The rapid phase of growth was characterized by an intense synthesis of many compounds in relatively high concentrations and later a sudden decrease in the number and amounts of substances. A slow successive, decline in the number and amounts of volatile components was observed during the phase of no net growth.The volatiles emitted by the fungus were concentrated, when most of the compounds were most abundant and the relative amounts of the major volatile neutral compounds were determined. The main components were ethyl acetate, ethyl propionate and ethanol.     

Plant‐extract‐induced changes in the proteome of the soil‐borne pathogenic fungus Thielaviopsis basicola

Thielaviopsis basicola is a hemibiotroph fungus that causes black root rot disease in diverse plants with significant impact on cotton production in Australia. To elucidate how T. basicola growth and proteome are influenced by interactions with natural sources, this fungus was cultured in the presence of root extracts from non‐host (wheat, hairy vetch) and susceptible host (cotton, lupin) plants. We found that T. basicola growth was significantly favored in the presence of host extracts, while hierarchical clustering analysis of 2‐DE protein profiles of T. basicola showed plant species had a larger effect on the proteome than host/non‐host status. Analysis by LC‐MS/MS of unique and differentially expressed spots and identification using cross‐species similarity searching and de novo sequencing allowed successful identification of 41 spots. These proteins were principally involved in primary metabolism with smaller numbers implicated in other diverse functions. Identification of several “morpho” proteins suggested morphological differences that were further microscopically investigated. Identification of several highly expressed spots suggested that vitamin B₆ is important in the T. basicola response to components present in hairy vetch extract, and finally, three spots, induced in the presence of lupin extract, may correspond to malic enzyme and be involved in lipid accumulation.     

Determination of volatile organic compounds in the stinkhorn fungus Pseudocolus fusiformis in different stages of fruiting body formation

A stinkhorn fungus was collected from the mountainous area of Yoshida campus, Yamaguchi University, Japan. Morphological characterization and similarity of large subunit ribosomal DNA sequences identified the fungus as Pseudocolus fusiformis. MonoTrap™ was combined with gas chromatography-mass spectrometry (GC-MS) to identify volatile organic compounds (VOCs) emitted from the fungus harvested at different stages of maturity. The main VOCs emitted from the mature fruiting body were 3-methyl-butanol, 4-methyl-phenol, and dimethyl tetrasulfide, while none of these compounds were detected in the egg-shaped state. Volatile sulfur-containing compounds, including dimethyl disulfide, trisulfide and tetrasulfide, which are commonly detected in stinkhorn fungi and truffles, were also emitted from this fungus. Furthermore, results elucidated that most VOCs occurred in the mature stage of Ps. fusiformis (fruiting body with arms fuse). This is the first study reporting VOC production of Ps. fusiformis.     

Antifungal effects of volatile organic compounds from the endophytic fungus Cryptosporiopsis ericae Cc-HG-7 isolated from Coptis chinensis Franch

In this study, 136 strains of endophytic fungi were isolated from the Chinese traditional medicinal plant Coptis chinensis Franch. Of these, 129 strains were classified into 12 different genera according to morphological traits and internal transcribed spacer (ITS) gene sequence analyses. Their antifungal activities were assessed against the following fungi: Magnaporthe oryzae, Pythium graminicola, Cylindrocarpon destructans, Fusarium oxysporum, Cercospora zeae-maydis, Sclerotinia sclerotiorum, Setosphaeria turcica and Botrytis cinerea. Fourteen endophytic strains were active against at least one of the selected fungi. The most active strain Cc-HG-7 identified as Cryptosporiopsis ericae displayed inhibition rates of 81.42% and 72.00%, respectively, against S. sclerotiorum and S. turcica in dual culture technique. The volatile antifungal compounds were identified using headspace solid-phase microextraction, followed by gas chromatography mass spectrometry to investigate the potential biocontrol mechanisms of strain Cc-HG-7. The results suggested that the strain Cc-HG-7 could be a potential agent for the biological control of S. sclerotiorum and S. turcica.     

Clerocidin selectively modifies the gyrase-DNA gate to induce irreversible and reversible DNA damage

Clerocidin (CL), a microbial diterpenoid, reacts with DNA via its epoxide group and stimulates DNA cleavage by type II DNA topoisomerases. The molecular basis of CL action is poorly understood. We establish by genetic means that CL targets DNA gyrase in the Gram-positive bacterium Streptococcus pneumoniae, and promotes gyrase-dependent single- and double-stranded DNA cleavage in vitro. CL-stimulated DNA breakage exhibited a strong preference for guanine preceding the scission site (−1 position). Mutagenesis of −1 guanines to A, C or T abrogated CL cleavage at a strong pBR322 site. Surprisingly, for double-strand breaks, scission on one strand consistently involved a modified (piperidine-labile) guanine and was not reversed by heat, salt or EDTA, whereas complementary strand scission occurred at a piperidine-stable −1 nt and was reversed by EDTA. CL did not induce cleavage by a mutant gyrase (GyrA G79A) identified here in CL-resistant pneumococci. Indeed, mutations at G79 and at the neighbouring S81 residue in the GyrA breakage-reunion domain discriminated poisoning by CL from that of antibacterial quinolones. The results suggest a novel mechanism of enzyme inhibition in which the −1 nt at the gyrase-DNA gate exhibit different CL reactivities to produce both irreversible and reversible DNA damage.     

Microbial consumption and production of volatile organic compounds at the soil-litter interface

Substantial amounts of volatile organic compounds (VOCs) can be released during decomposition and these compounds can affect atmospheric chemistry, belowground processes, and the structure of microbial communities in litter and soil. However, we have a limited understanding of the types, quantities and ecological impacts of VOCs emitted from litter. Here we used a closed flow-through system and proton transfer reaction mass spectrometry (PTR-MS) to characterize VOC emissions from soil and two litter types (Pinus taeda and Acer rubrum) over a 72-day incubation period. Microbial respiration rates were measured throughout the incubation, and the soils were harvested at the end of the incubation to determine how litter VOCs influenced soil C dynamics, N mineralization rates, and bacterial communities. Using the PTR-MS we identified over 100 VOCs, with 10 VOCs making up the majority of emissions. VOCs accounted for up to 2.5% of the C flux from litter. Soil was a net sink of litter VOCs, absorbing up to 80% of VOCs released by litter, and exposure of soil to litter VOCs increased microbial respiration rates in soil by up to 15%. However, we observed negligible impacts of litter VOCs on soil nutrient levels and bacterial community structure, suggesting that soils must be exposed to higher concentrations of VOCs than observed in our study, to cause effects on these soil characteristics. Overall, VOCs appear to have an important influence on C dynamics at the soil-litter interface and VOC emissions from decomposing litter may represent an understudied component of biosphere–atmosphere interactions.     

樟树幼苗机械损伤叶片对挥发性有机化合物及叶绿素荧光参数的影响

为探讨植物在机械损伤后C₆-C₁₀醛类化合物的释放机理, 及C₆-C₁₀醛类化合物对叶片光系统II (PSII)的影响, 以樟树(Cinnamomum camphora)为材料, 采用动态顶空气体循环法和热脱附/气相色谱/质谱联用技术(TDS-GC-MS), 对樟树幼苗叶片损伤后释放的C₆-C₁₀醛类化合物进行采集与分析, 并同步测定了脂氧合酶活性和损伤叶片的叶绿素荧光动力学参数。结果表明: 樟树幼苗叶片损伤后, 其挥发性有机化合物中己醛、庚醛、辛醛、壬醛和癸醛的释放量比损伤前分别增加了2.47、0.99、1.34、0.91和28.38倍(p < 0.01); 同时新增4种醛类化合物, 分别是: 2-己烯醛、2,4-己二烯醛、(E)-2-辛烯醛和(E)-2-壬烯醛。脂氧合酶活性比损伤前增加1.2倍(p < 0.01)。PSII单位反应中心复合体吸收的能量和被核心捕获的能量分别比损伤前下降12.8%和9.8% (p < 0.01)。单位面积反应中心的数量、电子传递量子产额、捕获激子能导致电子传递效率和叶片性能指数分别比损伤前增加23.3%、24.4%、22.6%和82.7% (p < 0.01)。损伤24 h后, 醛类化合物的种类、释放量、脂氧合酶活性及叶片叶绿素荧光动力学参数基本恢复到损伤前水平。说明机械损伤使PSII供体侧受损、脂氧合酶活性升高, 致使C₆-C₁₀醛类化合物大量释放, 樟树幼苗通过增加单位面积反应中心的数量来提高光合效率应对胁迫。     

迷迭香对干旱胁迫的生理响应及其诱导挥发性有机化合物的释放

为探讨干旱胁迫对迷迭香(Rosmarinus officinalis)生理生化特性及挥发性有机化合物(VOC)释放规律的影响, 该文采用盆栽称重控水法研究了轻度(LD)、中度(MD)和重度(SD)干旱胁迫对迷迭香二年生实生苗叶片细胞膜透性、可溶性糖、可溶性蛋白质和丙二醛(MDA)含量以及脂氧合酶和抗氧化保护酶活性的影响, 并采用热脱附/气相色谱/质谱联用技术对不同干旱胁迫下迷迭香释放的挥发性有机化合物成分进行了分析。结果表明: 干旱胁迫对迷迭香叶片可溶性糖和可溶性蛋白质含量有明显的影响, MD和SD处理12天时其含量极显著地增加(p < 0.01), 与对照相比可溶性糖分别增加了51.5%和87.4%, 可溶性蛋白质含量分别增加了0.82和1.40倍。在MD和SD胁迫下, 超氧化物歧化酶、过氧化物酶和过氧化氢酶对干旱胁迫的响应存在一定差异, 表现为相互协调的作用。随着干旱胁迫时间的延长, 迷迭香体内MDA含量极显著地增加(p < 0.01), 细胞膜损伤率显著增加。分析显示, 迷迭香释放的VOC主要是萜烯类化合物, 占总量的46.0%以上; 随着干旱胁迫增强, 迷迭香释放的VOCs总量减少, 种类增多; LD、MD和SD胁迫处理萜烯类化合物相对含量与对照相比分别增加了14.4%、17.0%和23.7%; 干旱胁迫还明显诱导绿叶挥发物(green leaf volatiles)和醛类化合物的释放, 诱导产生了2-己烯醛、叶醇、山梨醛和癸醛4种新组分。研究表明: 干旱胁迫条件下, 迷迭香能够通过调节保护酶活性、渗透调节物质含量和释放VOCs来提高抗旱性。     

The scent of disease: volatile organic compounds of the human body related to disease and disorder

Hundreds of volatile organic compounds (VOCs) are emitted from the human body, and the components of VOCs usually reflect the metabolic condition of an individual. Therefore, contracting an infectious or metabolic disease often results in a change in body odour. Recent progresses in analytical techniques allow rapid analyses of VOCs derived from breath, blood, skin and urine. Disease-specific VOCs can be used as diagnostic olfactory biomarkers of infectious diseases, metabolic diseases, genetic disorders and other kinds of diseases. Elucidation of pathophysiological mechanisms underlying production of disease-specific VOCs may provide novel insights into therapeutic approaches for treatments for various diseases. This review summarizes the current knowledge on chemical and clinical aspects of body-derived VOCs, and provides a brief outlook at the future of olfactory diagnosis.     

Ginger extract attenuates labetalol induced apoptosis,DNA damage,histological and ultrastructural changes in the heart of rat fetuses

Labetalol is a medication used to treat maternal hypertension during pregnancy. However, it is often associated with many side effects. Recently, several studies have been focused on the protective effect of medicinal plant extracts, such as ginger, against drugs inducing toxicity. Therefore, it has been hypothesized that ginger aqueous extraction can ameliorate labetalol-induced histological, ultrastructural changes, DNA damage, and apoptosis in fetal heart tissue. To achieve the aim of this study, sixty pregnant female albino rats were divided into 4 groups (15 each). Group I (Control). Group II received ginger (200 mg/kg). Group III received labetalol (300 mg/kg). Group IV received labetalol first followed by ginger. All groups were orally injected daily during the organogenesis phase of gestation i.e., from the 6th to the 15th day, and sacrificed at the 20th day of gestation. Results showed that labetalol-induced marked histological and ultrastructural alterations. Also, there was severe DNA damage and an increase in the apoptotic rates determined by Annexin-V/PI dual staining assay. Injection of the ginger aqueous extract caused evident improvement in cardiac tissue, DNA damage, and apoptotic rates. In conclusion, the results suggest that ginger extract could be a potential candidate agent for reducing labetalol-induced cardiotoxicity in the fetal heart of albino rats.     

Genotoxic stress-activated DNA-PK-p53 cascade and autophagy cooperatively induce ciliogenesis to maintain the DNA damage response

The DNA-PK maintains cell survival when DNA damage occurs. In addition, aberrant activation of the DNA-PK induces centrosome amplification, suggesting additional roles for this kinase. Here, we showed that the DNA-PK-p53 cascade induced primary cilia formation (ciliogenesis), thus maintaining the DNA damage response under genotoxic stress. Treatment with genotoxic drugs (etoposide, neocarzinostatin, hydroxyurea, or cisplatin) led to ciliogenesis in human retina (RPE1), trophoblast (HTR8), lung (A459), and mouse Leydig progenitor (TM3) cell lines. Upon genotoxic stress, several DNA damage signaling were activated, but only the DNA-PK-p53 cascade contributed to ciliogenesis, as pharmacological inhibition or genetic depletion of this pathway decreased genotoxic stress-induced ciliogenesis. Interestingly, in addition to localizing to the nucleus, activated DNA-PK localized to the base of the primary cilium (mother centriole) and daughter centriole. Genotoxic stress also induced autophagy. Inhibition of autophagy initiation or lysosomal degradation or depletion of ATG7 decreased genotoxic stress-induced ciliogenesis. Besides, inhibition of ciliogenesis by depletion of IFT88 or CEP164 attenuated the genotoxic stress-induced DNA damage response. Thus, our study uncovered the interplay among genotoxic stress, the primary cilium, and the DNA damage response.     

Mass production of bacterial communities adapted to the degradation of volatile organic compounds (TEX)

This study focuses on the mass cultivation of bacteria adapted to the degradation of a mixture composed of toluene, ethylbenzene, o-, m- and p-xylenes (TEX). For the cultivation process Substrate Pulse Batch (SPB) technique was adapted under well-automated conditions. The key parameters to be monitored were handled by LabVIEW software including, temperature, pH, dissolved oxygen and turbidity. Other parameters, such as biomass, ammonium or residual substrate concentrations needed offline measurements. SPB technique has been successfully tested experimentally on TEX. The overall behavior of the mixed bacterial population was observed and discussed along the cultivation process. Carbon and nitrogen limitations were shown to affect the integrity of the bacterial cells as well as their production of exopolymeric substances (EPS). Average productivity and yield values successfully reached the industrial specifications, which were 0.45 kg_DW m⁻³ d⁻¹ and 0.59 g_DW g_C⁻¹, respectively. Accuracy and reproducibility of the obtained results present the controlled SPB process as a feasible technique.     

Catechins induce oxidative damage to cellular and isolated DNA through the generation of reactive oxygen species

Green tea catechins have antimutagenic and anticarcinogenic activities. On the other hand, several epidemiological studies have indicated significant positive relationship between green tea consumption and cancer. Catechins enhance colon carcinogenesis in rats initiated with chemical carcinogen. To clarify the mechanism underlying the potential carcinogenicity, we investigated the DNA-damaging ability of catechins in human cultured cells. Catechin increased the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a characteristic oxidative DNA lesion, in human leukemia cell line HL-60 but not in HP100, a hydrogen peroxide (H

2

O

2

)-resistant cell line derived from HL-60. The catechin-induced formation of 8-oxodG in HL-60 cells significantly decreased by bathocuproine. Furthermore, we investigated DNA damage and its site-specificity induced by catechins, using

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P-labeled DNA fragments. Catechin and epicatechin induced extensive DNA damage in the presence of Cu(II). Catechin caused piperidine-labile sites at thymine and cytosine residues in the presence of Cu(II). Catalase and bathocuproine inhibited the DNA damage, indicating the involvement of H

2

O

2

and Cu(I). NADH enhanced catechins plus Cu(II)-induced 8-oxodG formation in calf thymus DNA, suggesting the redox cycle between catechins and their corresponding quinones, the oxidized forms of catechins. The DNA-damaging ability of epicatechin is stronger than that of catechin, possibly due to the greater turnover frequency of the redox cycle. The difference in their redox properties could be explained by their redox potentials estimated form an ab initio molecular orbital calculation. The present study demonstrated that catechins could induce metal-dependent H

2

O

2

generation during the redox reactions and subsequently damage to cellular and isolated DNA. Therefore, it is reasonably considered that green tea catechins may have the dual function of anticarcinogenic and carcinogenic potentials.     

DNA immunization with the ribosomal P2beta gene of Trypanosoma cruzi fails to induce pathogenic antibodies

Patients with chronic Chagas' heart disease (cChHD) develop a strong IgG response against the C-terminal region of the Trypanosoma cruzi ribosomal P2beta protein (TcP2beta). These antibodies have been shown to exert an in vitro chronotropic effect on cardiocytes through stimulation of the beta1-adrenergic receptor (beta1-AR). Moreover, the presence of antibodies recognizing the TcP2beta C-terminus was associated with cardiac alterations in mice immunized with the corresponding recombinant protein. Here, we demonstrate that DNA immunization could be used to modulate the specificity of the anti-TcP2beta humoral response in order to avoid the production of pathogenic antibodies. After DNA injection, we detected IgG antibodies that were directed only to internal epitopes of the TcP2beta molecule and that did not exert anti-beta1-AR functional activity, measured as an increase in intracellular cAMP levels of transfected COS-7 cells. Accordingly, DNA-immunized mice did not present electrocardiographic alterations. These data demonstrate that anti-TcP2beta antibodies elicited by DNA immunization are completely different in their specificity and functional activity from those produced during T. cruzi infection.     

Deadwood substrate and species-species interactions determine the release of volatile organic compounds by wood-decaying fungi

Wood-decaying fungi in the phylum Basidiomycota play a significant role in the global carbon cycle, as they decompose deadwood effectively. Fungi may compete for utilizable substrate and growth space by producing soluble metabolites and by releasing volatile organic compounds (VOCs). We determined the role of wood substrate (Scots pine or Norway spruce) on the generation of hyphal biomass, secreted metabolites and enzyme activities, wood decomposition rate, and fungal species-species interactions on VOC release. We studied one brown-rot species (Fomitopsis pinicola) and two white-rot species (Phlebia radiata and Trichaptum abietinum) cultivated individually or in combinations. Wood substrate quality influences VOC release by the wood-decaying fungi, with signature differences caused by the decomposition trait (brown rot or white rot) and species-species interactions. VOC release was higher in the cultures of Basidiomycota than in uncolonized sawdust. Fungal biomass, decomposition activity, iron reduction, enzyme activities, oxalate anion content, and oxalic acid production explained VOC release from decaying wood.     

Metabolic synergies in the biotransformation of organic and metallic toxic compounds by a saprotrophic soil fungus

Applied Microbiology and Biotechnology - The saprotrophic fungus Penicillium griseofulvum was chosen as model organism to study responses to a mixture of hexachlorocyclohexane (HCH) isomers...     

Reactive oxygen species contribute to the release of volatile organic compounds from Chlamydomonas reinhardtii during programmed cell death

Acetic acid at pH 5.0 can induce programmed cell death (PCD) in Chlamydomonas reinhardtii cells, and abundant volatile organic compounds (VOCs) were released during the process. In this study, the caspase‐3‐like activity was determined during the PCD, and it was increased significantly after 1 h. During the PCD, the dynamic release of VOCs from the cells was analyzed, and the emissions of total VOCs were raised markedly and reached the highest level at 2 h. Among the seven types of VOCs, such as alkanes, alkenes, terpenoids, alcohols, aldehydes, ketones and esters, three oxygenated compounds (aldehydes, ketones and esters) showed the most significant increase. O₂^‐· and H₂O₂ were rapidly accumulated to high levels in the cells at the beginning of the PCD, but their content was reduced during the process. The activities of antioxidant enzymes were reduced gradually and even disappeared completely, demonstrating that the reduction of reactive oxygen species (ROS) may not be scavenged by the antioxidant enzyme system. ROS have an intense oxidation and scavenging ability to volatile compounds, and the oxidation results in the production of oxygenated compounds. Therefore, the abundant production of oxygenated compounds indicated that ROS may play an important role in the dynamic release of VOCs from C. reinhardtii cells during PCD.