Chloroplast DNA molecular characterization and leaf volatiles analysis of mint (Mentha; Lamiaceae) populations in China

Non-coding chloroplast DNA (cpDNA) was used to evaluate genetic diversity and relationships within the section Mentha collected from China. Leaf volatiles of Mentha spicata accessions and its parent were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). To this end, genetic diversity of 30 Mentha accessions from different geographic origins of China, representing six species and two hybrids, was assessed. Molecular studies grouped the samples mainly according to genetic relationship established by conventional methods. Cluster analysis based on the leaf volatiles chemical composition of M. spicata accessions defined two main chemotypes: 1,8-cineole-piperitenone oxide type and limonene-carvone type. The results suggested that there was a high genetic variability among individuals of Mentha in China. A distinct correlation between cpDNA marker and volatile oils in M. spicata accessions was revealed. Moreover, the chemical composition followed maternal inheritance in M. spicata accessions. In conclusion, the genetic diversity of Mentha populations as shown in this study should play a critical role in future selection and breeding programs.     

互叶白千层（Melaleuca alternifolia）不同类型叶片精油组分差异比较

利用 MTBE 方法结合气相色谱—质谱联用（GC-MS）技术比较了互叶白千层嫩叶与老叶精油的挥发性组分差异。研究发现,在互叶白千层不同类型叶片精油中共检测到 10 种单萜、16 种倍半萜、5 种单萜衍生物及 1 种倍半萜衍生物共 32 种挥发性物质。互叶白千层不同类型叶片精油组分亦不同,互叶白千层老叶精油含量达5000.79 ng/g,嫩叶精油含量仅为 3 470.38ng/g。单萜类衍生物是互叶白千层精油的绝对含量及相对含量最高的一类化合物。松油烯-4-醇、松油烯、d-杜松萜烯及 2-蒈烯在互叶白千层精油中含量较高。互叶白千层不同叶片精油组成不同,以倍半萜类化合物种类最多。互叶白千层叶片的成熟度与松油烯-4-醇的含量亦相关。     

Effects of fire and fire intensity on the germination and establishment of Acacia karroo, Acacia nilotica, Acacia luederitzii and Dichrostachys cinerea in the field

Background

The native annual tobacco, Nicotiana attenuata, is found primarily in large ephemeral populations (typically for less than 3 growing seasons) after fires in sagebrush and pinyon-juniper ecosystems and in small persistent populations (for many growing seasons) in isolated washes typically along roadsides throughout the Great Basin Desert of the SW USA. This distribution pattern is due to its unusual germination behavior. Ephemeral populations are produced by the germination of dormant seeds from long-lived seed banks which are stimulated to germinate by a combination of unidentified positive cues found in wood smoke and the removal of inhibitors leached from the unburned litter of the dominant vegetation. Persistent populations may result where these inhibitors do not exist, as in washes or along disturbed roadsides. To determine if this germination behavior has influenced population structure, we conducted an AFLP (244 individuals), ISSR (175 individuals) and ISSR+ AFLP (175 individuals) analysis on plants originating from seed collected from populations growing in 11 wash and burns over 11 years from the SW USA.

Results

Genetic variance as measured by both ISSR and AFLP markers was low among sites and comparatively higher within populations. Cluster analysis of the Utah samples with samples collected from Arizona, California, and Oregon as out-groups also did not reveal patterns. AMOVA analysis of the combined AFLP and ISSR data sets yielded significantly low genetic differentiation among sites (Φct), moderate among populations within sites (Φsc) and higher genetic differentiation within populations (Φst).

Conclusions

We conclude that the seed dormancy of this post-fire annual and its resulting age structure in conjunction with natural selection processes are responsible for significantly low among sites and comparatively high within-population genetic variation observed in this species.     

Lipids and Composition of Fatty Acids of Saccharina latissima Cultivated Year-Round in Integrated Multi-Trophic Aquaculture

This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a reference site in Denmark (2013–2014). Generally, there was no difference in the biomass composition between sites; however, significant seasonal changes were found. The lipid concentration varied from 0.62%–0.88% dry weight (DW) in July to 3.33%–3.35% DW in November (p < 0.05) in both sites. The fatty acid composition in January was significantly different from all the other sampling months. The dissimilarities were mainly explained by changes in the relative abundance of 20:5n-3 (13.12%–33.35%), 14:0 (11.07%–29.37%) and 18:1n-9 (10.15%–16.94%). Polyunsaturated fatty acids (PUFA’s) made up more than half of the fatty acids with a maximum in July (52.3%–54.0% fatty acid methyl esters; FAME). This including the most appreciated health beneficial PUFA’s, eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), but also arachidonic (ARA) and stearidonic acid (SDA), which are not found in land vegetables such as cabbage and lettuce. Compared to fat (salmon) and lean fish (cod) this seaweed species contains higher proportions of ARA and SDA, but lower EPA (only cod) and DHA. Conclusively, the season of harvest is important for the choice of lipid quantity and quality, but the marine vegetables provide better sources of EPA, DHA and long-chain (LC)-PUFA’s in general compared to traditional vegetables.     

三角梅种质资源的ISSR分析

应用ISSR分子标记技术对68份三角梅种质进行分析,从100个引物中筛选出14个多态性丰富、重复性好的引物,对68份三角梅种质资源的DNA多态性检测共获得了195条谱带,其中多态性条带182条,多态性比率为93.3%。聚类分析结果表明,三角梅品种间的遗传相似系数在0.50～0.97之间,平均相似系数为0.67,这说明供试的68份材料间的遗传多样性不是特别丰富、亲缘关系较近。在0.64水平处将三角梅种质资源分为A类群和B类群,A类群可分为2亚类,B类群还可分为6亚类。本研究从分子水平上揭示了三角梅不同种质资源之间的亲缘关系,进一步明确了种质资源间的遗传距离,为三角梅优良品质性状的选择、杂交育种亲本选配和良种繁育,提供了DNA分子水平上的理论依据。     

Detection of disease in stored potatoes by volatile monitoring

The feasibility of early disease detection in potato storages by the monitoring of volatiles was investigated usingErwinia carotovora as a model storage pathogen (soft rot) in both laboratory and commercial site tests. Volatiles were collected by cryogenic air liquefaction and concentrrated on Tenax-GC adsorbent. Analyses by gas chromatography and mass spectroscopy identified acetone, ethanol, and 2-butanone being produced in abnormal concentrations during host-soft rot incubations in a controlled environment. Preliminary comparisons between diseased and normal commercial bins at different storage sites (two cultivars) indicated soft rot infection also created abnormally high concentrations of the above three volatiles, with most notable differences in 2-butanone concentrations. The criteria of selection for volatiles for possible use as incipient disease indicators are discussed in terms of the composite rate of pathogenic destruction within a potato pile. Additional volatiles identified from potatoes inoculated withE. carotovora include: acetaldehyde, methyl acetate, ethyl acetate, propanethiol, hydrogen sulfide, methyl sulfide, methyl disulfide, n-propanol, and isobutanol.     

Bioprospecting from Marine Sediments of New Brunswick,Canada: Exploring the Relationship between Total Bacterial Diversity and Actinobacteria Diversity

Actinomycetes are an important resource for the discovery of natural products with therapeutic properties. Bioprospecting for actinomycetes typically proceeds without a priori knowledge of the bacterial diversity present in sampled habitats. In this study, we endeavored to determine if overall bacterial diversity in marine sediments, as determined by 16S rDNA amplicon pyrosequencing, could be correlated with culturable actinomycete diversity, and thus serve as a powerful tool in guiding future bioprospecting efforts. Overall bacterial diversity was investigated in eight marine sediments from four sites in New Brunswick, Canada, resulting in over 44,000 high quality sequences (x = 5610 per sample). Analysis revealed all sites exhibited significant diversity (H’ = 5.4 to 6.7). Furthermore, statistical analysis of species level bacterial communities (D = 0.03) indicated community composition varied according to site and was strongly influenced by sediment physiochemical composition. In contrast, cultured actinomycetes (n = 466, 98.3% Streptomyces) were ubiquitously distributed among all sites and distribution was not influenced by sediment composition, suggesting that the biogeography of culturable actinomycetes does not correlate with overall bacterial diversity in the samples examined. These actinomycetes provide a resource for future secondary metabolite discovery, as exemplified by the antimicrobial activity observed from preliminary investigation.     

Volatile organic compounds as a diagnostic marker of late blight infected potato plants: A pilot study

Volatiles from potato plants infected with Phytophthora infestans (Mont.) de Bary were monitored by in situ headspace sampling. The sampling was done in four periods i.e. 28–42, 52–66, 76–90, and 100–114 h after inoculation (HAI). The headspace samples were analyzed by a gas chromatography–flame ionization detector (GC–FID) to assess the differences in volatile fingerprints between the infected-plant group and control groups, i.e. non-inoculated-plant and empty-vessel groups. The samples were subsequently analyzed by gas chromatography–mass spectrometry to identify specific peaks observed by GC–FID. Spore germination, infection, symptom development and sporulation were also monitored to ascertain the disease developmental stage when marker volatiles were first generated. The first symptoms of infection were visible after two days. Three marker volatiles i.e. (E)-2-hexenal, 5-ethyl-2(5H)-furanone and benzene-ethanol were found in the third and fourth trapping periods (3–4 days after inoculation) when sporangiophores were already formed. The volatile metabolites from blighted plants could be applied for sensor development to detect the occurrence of the disease in the field as well as for investigation of volatile production in relation to plant responses to infection.     

Evaluation of genetic diversity in turmeric (Curcuma longa L.) using RAPD and ISSR markers

Turmeric (Curcuma longa L.) is an industrially important plant used for production of curcumin, oleoresin and essential oil. In the present study we examined the genetic diversity among turmeric accessions from 10 different agro-climatic regions comprising 5 cultivars and 55 accessions. Two DNA-based molecular marker techniques, viz., random amplified polymorphism DNA (RAPD) and inter simple sequence repeat (ISSR) were used to assess the genetic diversity in turmeric genotypes. A total of 17 polymorphic primers (11 RAPDs and 6 ISSRs) were used in this study. RAPD analysis of 60 genotypes yielded 94 fragments of which 75 were polymorphic with an average of 6.83 polymorphic fragments per primer. Number of amplified fragments with RAPD primers ranged from 3 to 13 with the size of amplicons ranging from 230 to 3000 bp in size. The polymorphism ranged from 45 to 100 with an average of 91.4%. The 6 ISSR primers produced 66 bands across 60 genotypes of which 52 were polymorphic with an average of 8.6 polymorphic fragments per primer. The number of amplified bands varied from 1 to 14 with size of amplicons ranging from 200 to 2000 bp. The percentage of polymorphism using ISSR primers ranged from 83 to 100 with an average of 95.4%. Nei's dendrogram for 60 samples using both RAPD and ISSR markers demonstrated an extent of 62% correlation between the genetic similarity and geographical location. The result of Nei's genetic diversity (H) generated from the POP gene analysis shows relatively low genetic diversity in turmeric accessions of South eastern ghat (P7), Western undulating zone (P8) with 0.181 and 0.199 value whereas highest genetic diversity (0.257) has been observed in Western central table land (P9). Knowledge on the genetic diversity of turmeric from different agro-climatic regions can be used to future breeding programs for increased curcumin, oleoresin and essential oil production to meet the ever-increasing demand of turmeric for industrial and pharmaceutical uses.     

Tetrodotoxin concentrations in Pleurobranchaea maculata: temporal, spatial and individual variability from New Zealand populations

Tetrodotoxin (TTX) is a potent neurotoxin that has been identified in a range of phylogenetically unrelated marine and terrestrial organisms. Tetrodotoxin was recently detected in New Zealand in Pleurobranchaea maculata (the grey side-gilled sea slug). From June 2010 to June 2011 wild specimens were collected from 10 locations around New Zealand. At one site (Narrow Neck Beach, Auckland) up to 10 individuals were collected monthly for 6 months. Attempts were also made to rear P. maculata in captivity. Tetrodotoxin was detected in samples from eight of the ten sites. The highest average (368.7 mg kg⁻¹) and maximum (1414.0 mg kg⁻¹) concentrations were measured in samples from Illiomama Rock (Auckland). Of the toxic populations tested there was significant variability in TTX concentrations among individuals, with the highest difference (62 fold) measured at Illiomama Rock. Tetrodotoxin concentrations in samples from Narrow Neck Beach varied temporally, ranging from an average of 184 mg kg⁻¹ in June 2010 to 17.5 mg kg⁻¹ by December 2010. There was no correlation between TTX levels and mass. The highest levels correspond with the egg laying season (June–August) and this, in concert with the detection of high levels of TTX in eggs and early larval stages, suggests that TTX may have a defensive function in P. maculata. Only one larva was successfully reared to full maturation and no TTX was detected.     

3 种唇形科植物精油组分差异比较

利用水蒸气蒸馏法结合气相色谱—质谱联用技术比较了百里香、迷迭香和柠檬香蜂草 3 种唇形科植物精油的挥发性组分差异。结果表明，唇形科植物精油具有丰富的挥发性组分，本研究在不同唇形科植物精油中检测到 18 种单萜、18 种倍半萜、25 种单萜衍生物、2 种倍半萜衍生物及 16 种酮、酯、酸类化合物共 79 种挥发性物质。不同唇形科植物精油组分差异较大，百里香植物精油组分最多，具有 51 种化合物；其次为迷迭香和柠檬香蜂草精油。百里香酚、1,8-桉叶素和香叶醛分别对百里香、迷迭香和柠檬香蜂草植物精油的贡献率最高。     

Aroma profiles of the curry leaf, Murraya koenigii (L.) Spreng. chemotypes: Variability in north India during the year

Murraya koenigii (L.) Spreng. (Rutaceae) is characterized by a large chemical intraspecific variability among the land races. This fact makes it difficult to detect real changes occurring in their essential oil composition during annual cycle. Based on this, variations of essential oil yield and composition in two chemotypes (‘A’ and ‘B’) of M. koenigii were assessed in spring, summer, rainy, autumn and winter seasons under foot hill conditions of northern India. The essential oil yield ranged from 0.15% to 0.18% in chemotype ‘A’, while it varied from 0.12% to 0.14% in chemotype ‘B’. Essential oils of both chemotypes from different seasons were analysed by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). A total of fifty-eight constituents representing 93.7-98.8% of chemotype ‘A’ and fifty-six constituents forming 96.1-98.7% of the total composition of chemotype ‘B’ were identified. Chemotype ‘A’ was characterized by higher percentages of α-pinene (34.6-41.9%), sabinene (26.1-36.1%), (E)-caryophyllene (2.4-5.4%) and terpinen-4-ol (1.5-5.3%), whereas chemotype ‘B’ was dominated by higher amount of α-pinene (52.7-65.3%), β-pinene (10.7-12.9%), (E)-caryophyllene (3.1-10.3%) and limonene (5.1-7.8%). Comparative results showed considerable variations in the essential oil composition of both chemotypes due to season of collection. Present study concluded that the M. koenigii leaves of desired quality may be obtained by selecting suitable chemotype and season.     

橡胶树抗寒种质遗传多样性分析

应用RAPD和ISSR技术对20份橡胶树抗寒种质进行遗传多样性分析。结果表明，16个RAPD引物和12个ISSR引物分别扩增出条带113和101条，多态性条带指数(PPB)分别为61.1%和63.4%。据Nei-Li相似系数，ISSR标记在相似系数约0.74处，可将20份材料分为野生种质和栽培种质两大类；RAPD标记在相似系数约0.70处，也可将供试材料分为野生种质和栽培种质两类，但只有XJ002420为野生种质。对2种标记的分析结果进行相关分析，结果表明，RAPD和ISSR所检测的遗传相似系数呈极显著正相关，相关系数为0.672。以上结论表明，RAPD和ISSR标记可用于橡胶树种质资源的遗传多样性研究，但鉴于ISSR较RAPD有更强的多态性检出能力，ISSR技术应作为遗传多样性研究的首选单引物标记。     

Mechanisms for coping with submergence and waterlogging in rice

Rice (Oryza sativa L.), unlike other cereals, can grow well in paddy fields and is highly tolerant of excess water stress, from either submergence (in which part or all of the plant is under water) or waterlogging (in which excess water in soil limits gas diffusion). Rice handles submergence stress by internal aeration and growth controls. A quiescence strategy based on Submergence-1A (SUB1A) or an escape strategy based on SNORKEL1 (SK1) and SNORKEL2 (SK2) is used for the growth controls. On the other hand, rice handles waterlogging stress by forming lysigenous aerenchyma and a barrier to radial O₂ loss (ROL) in roots in order to supply O₂ to the root tip. In this article, we summarize recent advances in understanding the mechanisms of responding to excess water stresses (i.e., submergence and waterlogging) in rice and other gramineous plants.     

Photoprotective Bioactivity Present in a Unique Marine Bacteria Collection from Portuguese Deep Sea Hydrothermal Vents

Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications.     

The Marine-Derived Fungus Clonostachys rosea,Source of a Rare Conjugated 4-Me-6E,8E-hexadecadienoic Acid Reducing Viability of MCF-7 Breast Cancer Cells and Gene Expression of Lipogenic Enzymes

A marine-derived strain of Clonostachys rosea isolated from sediments of the river Loire estuary (France) was investigated for its high lipid production. The fungal strain was grown on six different culture media to explore lipid production changes. An original branched conjugated fatty acid, mainly present in triglycerides and mostly produced when grown on DCA (23% of total fatty acid composition). It was identified as 4-Me-6E,8E-hexadecadienoic on the basis of spectroscopic analyses. This fatty acid reduced viability of MCF-7 breast cancer cells in a dose dependent manner (up to 63%) at physiological free fatty acid human plasma concentration (100 μM). Reduction of gene expression of two lipogenic enzymes, the acetyl CoA carboxylase (ACC) and the fatty acid synthase (FAS) was evaluated to explore the mechanisms of action of 4-Me-6E,8E-16:2 acid. At 50 μM, 50% and 35% of mRNA gene expression inhibition were observed for ACC and FAS, respectively.     

The sulfur components of Allium species as flavoring matter

Gas chromatographic analysis of the headspace volatiles from various kinds ofAllium (onions) revealed the principal disulfides present as being: di-n-propyl, n-propyl allyl, methyl-n-propyl, methyl allyl, dimethyl and diallyl. These aliphatic disulfides appear to be one of the principal groups of compounds responsible for the aroma and flavor of onions. A procedure for the qualitative and quantitative determination of these compounds is discussed. Comparisons are made between disulfide composition of various species and also between fresh and dehydrated onion samples. The amounts of volatile disulfides lost on dehydration are discussed.     

Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques

The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.     

Geographical origin and drying methodology may affect the essential oil of Lippia alba (Mill) N.E. Brown

Lippia alba (Mill.) N.E. Brown, the ginger grass, is a medicinal and aromatic plant widely used in Latin America. In this work the effect of the geographical origin and different drying methodologies on L. alba leaves production, essential oil content and composition were evaluated. Field experiments were conducted in three different municipalities (Amargosa, Cruz das Almas and Santo Antônio de Jesus) from Bahia region (Brazil) and two drying methodologies (traditional and artificial with controlled conditions) were assessed. Fresh and dried leaves essential oils were extracted by hydro-distillation and their volatiles were determined by gas chromatography.The geographical origin affected the mass production, essential oil content and both qualitative and quantitative fractions of their composition. Leaves from Cruz das Almas had higher yield in essential oil content. Overall, 26 oil constituents were identified. Carvone, germacrene D and limonene were the main oil constituents. The drying methodologies combined with the geographic origin influenced essential oil composition showing that L. alba constituents were influenced by post-harvest treatments. Some constituents were sensitive to both methods applied, while some enhanced their content like germacrene D.     

Low variability of flower volatiles of Rosa damascena Mill. plants from rose plantations along the Rose Valley, Bulgaria

The composition of volatile compounds in the rose essential oils obtained from the rose flowers has been known to be affected by a number of factors including the region of rose growing. The variations of the flower volatile composition of Rosa damascena plants growing in 11 different rose plantations along the famous Rose Valley in Bulgaria were studied following GC/MS metabolite profiling. ANOVA statistical test revealed that only 14 of a total of 90 identified compounds were significantly influenced by the geographic location of the sampled rose plantation. The hierarchical clustering analysis based on the subset of these 14 compounds revealed no clear correlation between the levels of rose flower volatiles and geographic location of the studied rose plantations. The results from the study suggest low variability of rose flower volatiles accumulation and elevated plasticity of the common R. damascena genotype industrially cultivated in the Rose Valley.