Quantification of Cyanamide Contents in Herbaceous Plants

Cyanamide (NH₂CN) is found in nature, although it has long been recognized as an industrial product. Distribution of cyanamide in the plant kingdom was investigated using a direct quantitative determination method to detect and measure cyanamide by stable isotope dilution gas chromatography–mass spectrometry (the SID–GC–MS method). The SID–GC–MS method proved to be a robust way to quantify cyanamide contents in the extracts of 101 species of herbaceous plants. The average recovery of cyanamide from all plants tested was 55.6±20.3%. Vicia villosa and V. cracca contained cyanamide at 369–498 μg/gFW and 3,460–3,579 μg/gFW respectively, while the other 99 species contained no detectable cyanamide (<1 μg/gFW). This result suggests that distribution of cyanamide in the plant kingdom is limited and uneven.     

Functional characterization of CmCCD1, a carotenoid cleavage dioxygenase from melon

Carotenoids are nutritionally important tetraterpenoid pigments that upon oxidative cleavage give rise to apocarotenoid (norisoprene) aroma volatiles. beta-Carotene is the predominant pigment in orange-fleshed melon (Cucumis melo L.) varieties, reaching levels of up to 50 microg/gFW. Pale green and white cultivars have much lower levels (0-10 microg/gFW). In parallel, beta-ionone, the 9,10 cleavage product of beta-carotene, is present (12-33ng/gFW) in orange-fleshed melon varieties that accumulate beta-carotene, and in much lower levels (0-5 ng/gFW) in pale green and white fleshed varieties. A search for a gene putatively responsible for the cleavage of beta-carotene into beta-ionone was carried out in annotated melon fruit EST databases yielding a sequence (CmCCD1) highly similar (84%) to other plant carotenoid cleavage dioxygenase genes. To test its function, the clone was overexpressed in Escherichia coli strains previously engineered to produce different carotenoids. We show here that the CmCCD1 gene product cleaves carotenoids at positions 9,10 and 9',10', generating geranylacetone from phytoene; pseudoionone from lycopene; beta-ionone from beta-carotene, as well as alpha-ionone and pseudoionone from delta-carotene. CmCCD1 gene expression is upregulated upon fruit development both in orange, pale-green and white melon varieties, despite the lack of apocarotenoid volatiles in the later. Thus, the accumulation of beta-ionone in melon fruit is probably limited by the availability of carotenoid substrate.     

Selenium hyperaccumulation reduces plant arthropod loads in the field

The elemental defense hypothesis proposes that some plants hyperaccumulate toxic elements as a defense mechanism. In this study the effectiveness of selenium (Se) as an arthropod deterrent was investigated under field conditions. Arthropod loads were measured over two growing seasons in Se hyperaccumulator habitats in Colorado, USA, comparing Se hyperaccumulator species (Astragalus bisulcatus and Stanleya pinnata) with nonhyperaccumulators (Camelina microcarpa, Astragalus americanus, Descurainia pinnata, Medicago sativa, and Helianthus pumilus). The Se hyperaccumulating plant species, which contained 1000-14 000 microg Se g(-1) DW, harbored significantly fewer arthropods (c. twofold) and fewer arthropod species (c. 1.5-fold) compared with nonhyperaccumulator species that contained < 30 microg Se g(-1) DW. Arthropods collected on Se-hyperaccumulating plants contained three- to 10-fold higher Se concentrations than those found on nonhyperaccumulating species, but > 10-fold lower Se concentrations than their hyperaccumulator hosts. Several arthropod species contained > 100 microg Se g(-1) DW, indicating Se tolerance and perhaps feeding specialization. These results support the elemental defense hypothesis and suggest that invertebrate herbivory may have contributed to the evolution of Se hyperaccumulation.     

广东鼎湖山自然保护区生物主模式标本内容分析

为了解鼎湖山物种分类学研究的历史,采用内容分析法对采自广东鼎湖山自然保护区的生物主模式标本信息进行了分析。结果表明,鼎湖山自然保护区的生物主模式标本共含202种生物(亚种或变种),分属3界10门20纲54目104科146属,其中植物界63种、动物界68种、菌物界71种。有194份标本(另8份无采集人信息)涉及77位采集人(或其团队),有67家机构的147人参与新种命名, 67种期刊的140条文献参与新种发表, 38个国内外机构保存了200种的标本,物种在30%的科、目、采集人、第1命名人、期刊和存放地各分配了约70%的数量,呈现类似"二八定律"所述的不平衡现象。1978至1997年是标本采集并命名的高峰期,标本采集率为55.45%、标本命名率为58.91%;植物标本的采集和命名早于动物和真菌。鼎湖山物种的橱柜时间(标本采集到命名间隔的时间)平均为7.56 a,且植物的长于动物和菌物。鼎湖山主模式标本生物的物种密度比邻近保护区的要高。     

Comparison of phosphorylation patterns across eukaryotes by discriminative N-gram analysis

Background

How protein phosphorylation relates to kingdom/phylum divergence is largely unknown and the amino acid residues surrounding the phosphorylation site have profound importance on protein kinase–substrate interactions. Standard motif analysis is not adequate for large scale comparative analysis because each phophopeptide is assigned to a unique motif and perform poorly with the unbalanced nature of the input datasets.

Results

First the discriminative n-grams of five species from five different kingdom/phyla were identified. A signature with 5540 discriminative n-grams that could be found in other species from the same kingdoms/phyla was created. Using a test data set, the ability of the signature to classify species in their corresponding kingdom/phylum was confirmed using classification methods. Lastly, ortholog proteins among proteins with n-grams were identified in order to determine to what degree was the identity of the detected n-grams a property of phosphosites rather than a consequence of species-specific or kingdom/phylum-specific protein inventory. The motifs were grouped in clusters of equal physico-chemical nature and their distribution was similar between species in the same kingdom/phylum while clear differences were found among species of different kingdom/phylum. For example, the animal-specific top discriminative n-grams contained many basic amino acids and the plant-specific motifs were mainly acidic. Secondary structure prediction methods show that the discriminative n-grams in the majority of the cases lack from a regular secondary structure as on average they had 88 % of random coil compared to 66 % found in the phosphoproteins they were derived from.

Conclusions

The discriminative n-grams were able to classify organisms in their corresponding kingdom/phylum, they show different patterns among species of different kingdom/phylum and these regions can contribute to evolutionary divergence as they are in disordered regions that can evolve rapidly. The differences found possibly reflect group-specific differences in the kinomes of the different groups of species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-015-0657-2) contains supplementary material, which is available to authorized users.     

Characterization of the phenolic constituents in Mauritian endemic plants as determinants of their antioxidant activities in vitro

The phenolic constituents of Mauritian endemic plants from the Rubiaceae and Myrtaceae family were assessed and correlated with their potential antioxidant activities in vitro. The antioxidant activities of the plant extracts ranged from 0.27 to 1.49mmol Trolox equivalent/g FW and from 0.20 to 1.39mmol Fe(II) equivalent/g FW in the TEAC and FAP assays, respectively, with Syzygium commersonii showing the highest activity in these two systems. Eugenia orbiculata and all the Syzygium species were effective scavengers of hypochlorous acid while Monimiastrum acutisepalum was the most potent inhibitor of deoxyribose degradation. The plant extracts inhibited microsomal lipid peroxidation with low IC(50)s ranging from 0.02 to 1.75mgFW/mL when reaction was initiated with Fe(3+)/ascorbate and from 0.093 to 1.55mgFW/mL in the AAPH-dependent lipid peroxidation. The potential prooxidant nature of the plant extracts was compared with ascorbate (250microM) using copper-phenanthroline assay. The plant extracts at concentrations up to 5gFW/L were not prooxidant. However, Myonima nitens, Syzygium commersonii, Syzygium glomeratum and Syzygium mauritianum at concentrations of 10gFW/L had potency approaching 50% of the prooxidant activity of ascorbic acid in vitro, suggesting relative safeties. The total phenolics influenced the antioxidant activities in the TEAC, FRAP and HOCl scavenging assays whereas a negative correlation was observed with the deoxyribose assay. The high levels of polyphenolic compounds and the significant antioxidant activities of these Rubiaceae and Myrtaceae plant family make them suitable candidates as prophylactic agent.     

Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation

Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2-10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2-6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement.     

Distribution of chlorosulpholipids in algae

About 30 species of algae, chosen from a wide range of algal classes and orders, have been examined to see whether the chlorosulpholipids are widely distributed in this division of the plant kingdom. Most of the fresh-water species examined contained chlorosulpholipids, although only Ochromonas danica and O. malhamensis contained large quantities. The chlorosulpholipids of O. malhamensis were predominantly of the tetracosane series, the parent compound of which was tetracosane-1, 14-diol disulphate. No chlorosulpholipids were detected in any of the marine species examined.     

Proteinase Inhibitor-inducing Factor in Plant Leaves: A Phylogenetic Survey

Thirty-nine plant species representing 20 families from the four major divisions of plants were surveyed for the presence of proteinase inhibitor-inducing factor activity in leaves or other tissues. Tissue juices were assayed for their capacity to induce accumulation of proteinase inhibitor I in excised tomato (Lycopersico esculentum) leaves. In tissues of only 2 of the 39 species was proteinase inhibitor-inducing factor-like activity not found. The activity was absent in cabbage leaves and celery stalks. Fruiting bodies from one of three fungi genera assayed contained exceptionally large quantities of proteinase inhibitor-inducing factor-like activity. Extracts from Agraricus campestris fruiting bodies contained over 20 times more activity than tomato leaf juice. The survey confirms that substances with proteinase inhibitor-inducing factor-like activity are widespread in the plant kingdom.     

Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia virgata (Jacq), Salvia staminea (Montbret & Aucher ex Bentham) and Salvia verbenaca (L.) from Turkey

This study was designed to examine the in vitro antioxidant activities and rosmarinic acid levels of the methanol extracts of Salvia virgata, Salvia staminea and Salvia verbenaca. The extracts were screened for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid systems. In the first case, the most active plant was S. verbenaca (14.30+/-1.42 microg mg(-1)), followed by S. virgata (65.70+/-2.12 microg mg(-1)). S. staminae exhibited the weakest antioxidant activity in this test system of which IC(50) value is 75.40+/-0.57 microg mg(-1). In beta-carotene/linoleic acid test system, S. verbenaca extract was superior to the other extracts studied (inhibition value is 77.03%+/-0.42). Antioxidant activities of BHT, ascorbic acid, curcumin and alpha-tocopherol were determined in parallel experiments. Activity of rosmarinic acid was also screened for better establishing the relationship between rosmarinic acid level and antioxidant activity for the plant extracts. According to the results obtained by spectrophotometric analysis and further supported by HPLC, S. verbenaca has the highest rosmarinic acid level with a value of 29.30+/-0.24 microg mg(-1). Our results showed that the rosmarinic acid and its derivatives are more likely to be responsible for most of the observed antioxidant activities of Salvia species.     

Rapid identification of Mycobacterium species by lectin agglutination

The purpose of the present study is to explore the possibility that plant lectins can be used for the development of rapid and inexpensive technique for differentiation of mycobacterial species. The method is based on interaction between mycobacteria and lectins as visualized by agglutination in a microtiter plate. We employed 18 mycobacterium species and determined the minimal lectin concentration (MLC) of 23 different lectins. For some of the bacteria as a high as 1000 microg/ml of one or more lectins were required to induce agglutination, while for other strains as low as 1.95 microg/ml of the lectin were needed. A unique pattern of agglutination was observed for each species over a range of 62-1000 microg/ml lectin concentrations. There were little or no variations in MLC within strains (intraspecies) of each of two species tested. In contrast, there were marked interspecies variations in MLC. Analysis of the MLC showed that the highest score of interspecies differences with 23 lectins was obtained at 125 microg/ml lectin concentration. At this concentration it was found that the pattern of agglutinations with only two lectins was sufficient to differentiate mycobacterium species from each other. Because the bacteria-lectin interaction is adaptable to various methods of visualization, our findings may set the stage for developing a rapid and reliable tool to differentiate mycobacterium species.     

Structural diversity of fructans from members of the order Asparagales in New Zealand

The water-soluble carbohydrates (WSCs) extracted from the underground parts of Arthropodium cirratum, Astelia banksii, Bulbinella hookeri, Dianella nigra and Xeronema callistemon, and the flower stem of Phormium tenax have been investigated. Extracts of A. cirratum, B. hookeri, D. nigra and P. tenax contained 108.4, 28.1, 41.9 and 29.7 mg gFW(-1) WSCs, respectively. Thin-layer chromatography (TLC) showed that these species contained fructans. Extracts of A. banksii and X. callistemon each contained 11 mg gFW(-1) WSCs or less, and TLC detected only monosaccharides and sucrose. Reverse-phase (RP) HPLC and glycosyl linkage analysis showed that extracts of B. hookeri contained predominantly a linear series of fructans, with 1-linked and terminal fructofuranosyl (Fruf) residues and terminal glucopyranose (Glcp). RP-HPLC of extracts of A. cirratum, D. nigra and P. tenax showed a more complex pattern of oligosaccharides. Linkage analysis showed that these extracts contained fructans with 1-linked Fruf, 6-linked Fruf and 1,6-branched Fruf. Extracts of D. nigra and P. tenax contained 6-Glcp with only trace amounts of terminal Glcp, while A. cirratum contained mostly terminal Glcp with a trace of 6-Glcp. Differences in fructan and fructo-oligosaccharide structure between species shown in this study, together with published data, suggests that there are differences in the activities of the various fructosyltransferases responsible for biosynthesis of fructans in species within the Asparagales.     

Influence of citric acid amendments on the availability of weathered PCBs to plant and earthworm species

A series of small and large pot trials were conducted to assess the phytoextraction potential of several plant species for weathered polychlorinated biphenyls (PCBs) in soil (105 microg/g Arochlor 1268). In addition, the effect of citric acid on PCB bioavailability to both plants and earthworms was assessed. Under small pot conditions (one plant, 400 g soil), three cucurbits (Cucurbita pepo ssp pepo [zucchini] and ssp ovifera [nonzucchini summer squash], Cucumis sativus, cucumber) accumulated up to 270 microg PCB/g in the roots and 14 microg/g in the stems, resulting in 0.10% contaminant removal from soil. Periodic 1 mM subsurface amendments of citric acid increased the stem and leaf PCB concentration by 330 and 600%, respectively, and resulted in up to a 65% increase in the total amount of contaminant removed from soil. Although citric acid at 10 mM more than doubled the amount of PCB desorbed in abiotic batch slurries, contaminant accumulation by two earthworm species (Eisenia foetida and Lumbricus terrestris) was unaffected by citric acid at 1 and 10 mM and ranged from 11-15 microg/g. Two large pot trials were conducted in which cucurbits (C. pepo ssp pepo and ssp ovifera, C. sativus) and white lupin (Lupinus albus) were grown in 70 kg of PCB-contaminated soil White lupin was the poorest accumulator of PCBs, with approximately 20 microg/g in the roots and 1 microg/g in the stems. Both C. pepo ssp ovifera (summer squash) and C. sativus (cucumber) accumulated approximately 65-100 microg/g in the roots and 6-10 microg/g in the stems. C. pepo ssp pepo (zucchini) accumulated significantly greater levels of PCB than all other species, with 430 microg/g in the roots and 22 microg/g in the stems. The mechanism by which C. pepo spp pepo extracts and translocates weathered PCBs is unknown, but confirms earlier findings on the phytoextraction of other weathered persistent organic pollutants such as chlordane, p,p'-DDE, and polycyclic aromatic hydrocarbons.     

Isoarnottinin 4'-glucoside, a glycosylated coumarin from Prangos uloptera, with biological activity

Coumarins are a well-known group of natural products distributed in the plant kingdom especially in the family Apiaceae with various biological activities. Isoarnottinin 4'-glucoside is a simple glycosylated coumarin found previously in a few genera of Apiaceae, and its biological activities have not been previously described in details. In the present paper, the compound was isolated from Prangos uloptera (Apiaceae) leaves using HPLC techniques. Antimicrobial, phytotoxic and cytotoxic activities of the compound were evaluated by disk diffusion, lettuce assay and MTT method. Our results indicated that the compound has high antibacterial effect against Erwinia carotovora, a common plant pathogen with MIC value of 100 microg/mL. The compound also exhibited significant phytotoxic activity against lettuce and modest cytotoxic activity against HeLa cell line with IC50 of 0 .84 mg/mL. It could be concluded that isoamottinin 4'-glucoside may play phytoalexin or allelopathic role for plant and may be a candidate for an antibacterial agent or a bioherbicide.     

Evolution Analysis of Simple Sequence Repeats in Plant Genome

Simple sequence repeats (SSRs) are widespread units on genome sequences, and play many important roles in plants. In order to reveal the evolution of plant genomes, we investigated the evolutionary regularities of SSRs during the evolution of plant species and the plant kingdom by analysis of twelve sequenced plant genome sequences. First, in the twelve studied plant genomes, the main SSRs were those which contain repeats of 1–3 nucleotides combination. Second, in mononucleotide SSRs, the A/T percentage gradually increased along with the evolution of plants (except for P. patens). With the increase of SSRs repeat number the percentage of A/T in C. reinhardtii had no significant change, while the percentage of A/T in terrestrial plants species gradually declined. Third, in dinucleotide SSRs, the percentage of AT/TA increased along with the evolution of plant kingdom and the repeat number increased in terrestrial plants species. This trend was more obvious in dicotyledon than monocotyledon. The percentage of CG/GC showed the opposite pattern to the AT/TA. Forth, in trinucleotide SSRs, the percentages of combinations including two or three A/T were in a rising trend along with the evolution of plant kingdom; meanwhile with the increase of SSRs repeat number in plants species, different species chose different combinations as dominant SSRs. SSRs in C. reinhardtii, P. patens, Z. mays and A. thaliana showed their specific patterns related to evolutionary position or specific changes of genome sequences. The results showed that, SSRs not only had the general pattern in the evolution of plant kingdom, but also were associated with the evolution of the specific genome sequence. The study of the evolutionary regularities of SSRs provided new insights for the analysis of the plant genome evolution.     

Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is not always accompanied with enhancement of ROS production

Mode of action of allelochemicals in target plants is currently widely studied. Cyanamide is one of the newly discovered allelochemical, biosynthesized in hairy vetch. Recently, it has been recognized that cyanamide is plant growth inhibitor, which affects mitosis in root tip cells and causes,e.g., disorder in phytohormonal balance. We also demonstrated that CA may act as oxidative stress agent but it strictly depends on plant species, exposure time and doses. Roots of tomato seedling treated with water solution of 1.2 mM cyanamide did not exhibit elevated reactive oxygen species concentration during the whole culture period.     

In vitro activity of linezolid and eperezolid, two novel oxazolidinone antimicrobial agents, against anaerobic bacteria

Linezolid (formerly U-100766) and eperezolid (formerly U-100592) are novel oxazolidinone antimicrobial agents that are active against multi-drug-resistant staphylococci, streptococci, enterococci, corynebacteria, and mycobacteria. Preliminary studies also demonstrated that the compounds inhibited some test strains of anaerobic bacteria. Therefore, we extended the in vitro evaluation of these agents to include a total of 54 different anaerobic species. Minimal inhibitory concentration (MIC) values were determined using a standard agar dilution method for 143 anaerobic bacterial isolates. Eperezolid and linezolid demonstrated potent activity against the anaerobic Gram-positive organisms with most MIC values in the range of 0.25-4 microg/mL. Viridans streptococci demonstrated MICs of 1-2 microg/mL; Peptostreptococcus species and Propionibacterium species were inhibited by 相似文献   

A single HPLC-PAD-APCI/MS method for the quantitative comparison of phenolic compounds found in leaf, stem, root and fruit extracts of Vaccinium angustifolium

A method was developed for the analysis of Vaccinium angustifolium Ait. (Lowbush blueberry), which is a widely used natural health product, particularly for the treatment of diabetic symptoms. While the anthocyanin content of the fruit has been well characterized, the chemistry of the vegetative parts used in supportive therapy for diabetes has been largely ignored. Using a metabolomics-based approach for compound identification with an emphasis on phenolic metabolites, a single HPLC-PAD-APCI/ MS method was developed for the separation and quantitation of the major metabolites found in the 95% ethanol extracts of leaf, stem, root and fruit. The leaf extract contained high concentrations of chlorogenic acid (approximately 100 microg/mg extract) and a variety of quercetin glycosides that were also detected in the fruit and stem extracts. Flavan-3-ol monomers (+)-catechin and (-)-epicatechin were found in all plant parts but their procyanidin dimers were exclusively identified in the stem and root. The accuracy and precision of the presented method were corroborated by low intra- and inter-day variations in quantitative results in all plant part extracts. Further validation of the extraction and analytical protocols focused on identified compounds with reputed anti-diabetic activity, revealing recoveries greater than 80% and detection limits of 0.12-2.73 microg/mL.     

An assessment of the cultural capabilities of protoplasts of some wild species of linum

Protoplasts of several wildLinum species were isolated enzymatically from roots, hypocotyls and cotyledons of seedlings, and also from theirin vitro grown shoots and cell suspension cultures. When cultured all these protoplasts divided to produce callus but only good plant regeneration capability was evident in the case ofLinum lewissii and to a much lesser extent forL. strictum. Only rhizogenesis was observed withL. alpinum, L. narbonense, L. grandiflorum andL. altaicum. The high plant regeneration capacity ofL. lewissii from protoplast -derived tissues ofin vitro shoots and cell suspension cultures makes this species an attractive experimental system for somatic genetic manipulation.Abbreviations BAP benzylaminopurine - NAA -naphthaleneacetic acid - CPW cell and protoplast wash solution - gFW gram fresh weight On leave from Department of Crop Sciences University of Alexandria Egypt     

Differential distribution of tocopherols and tocotrienols in photosynthetic and non-photosynthetic tissues

Tocopherols and tocotrienols are vitamin E compounds, differing only in the saturation state of the isoprenoid side chain. Tocopherol biosynthesis, physiology and distribution have been studied in detail. Tocopherols have been found in many different plant species, and plant tissues. In contrast, comparatively little is known about the physiology and distribution of tocotrienols. These compounds appear to be considerably less widespread in the plant kingdom. In this study 80 different plant species were analysed for the presence of tocotrienols. Twenty-four species were found to contain significant amounts of tocotrienols. No taxonomic relation was apparent among the 16 dicotyledonous species that were found to contain tocotrienol. Monocotyledonous species (eight species) belonged either to the Poaceae (six species) or the Aracaceae (two species). A more detailed analysis of tocotrienol accumulation revealed the presence of tocotrienols in several non-photosynthetic tissues and organs, i.e. seeds, fruits and in latex, in concentrations up to 2000 ppm. No tocotrienols could be detected in mature photosynthetic tissues. However, we found the transient accumulation of low levels of tocotrienols in the young coleoptiles of plant species whose seeds contained tocotrienols. No measurable tocotrienol biosynthesis was apparent in coleoptiles, or in chloroplasts isolated from such coleoptiles. In line with these results, we found that tocotrienol accumulation in coleoptiles was not associated with chloroplasts. Based on our data, we conclude that tocotrienols may be transiently present in photosynthetically active tissues, however, it remains to be proven whether the tocotrienols are biosynthesised in such tissues, or imported from elsewhere in the plant.