Determination of phenolic compounds and diterpenes in roots of Salvia miltiorrhiza and Salvia przewalskii by two LC–MS tools: Multi-stage and high resolution tandem mass spectrometry with assessment of antioxidant capacity

Comparative phytochemical analyses of hydroalcoholic (50% EtOH) extracts from roots of S. miltiorrhiza (SM) and S. przewalskii (SP) were performed using two complementary LC–MS systems: the first system HPLC-DAD-MSⁿ an ion trap mass spectrometer and the second system consisted high resolution MS/MS Orbitrap mass spectrometer. The individual compounds were identified using a previously published approach via comparison of the exact molecular masses, mass spectra and retention times to those of standard compounds, online available databases and literature data. Moreover, the determination of antioxidative activities of extracts by DPPH and FRAP methods was carried out. Analysis allowed to identify 39 chemical compounds in extracts from both species. Extract from root of SP differs from SM in the presence of several metabolites such as: przewalskinic acid and their derivatives, przewaquinone C, przewaquinonate A, glycosides of rosmarinic acid, methyltanshinonate, whereas tanshinones, salvianolic acids and lithospermic acids occurred in both species. Moreover, it was shown that hydroalcoholic extract from roots of SM exerted stronger antioxidant properties in a FRAP test (max. 323.92 μM Fe²⁺/L) and in DPPH test (max. 78.64 nM TE) in comparison with SP extract.     

Modeling the formation of root apices

The formation of new root apices from small groups of cells with different cellular patterns has been simulated using an existing model based on growth tensors. To generate an apex, a steady growth field was used. The pattern of cells evolved to approach the steady state. Two extreme types of progressions have been obtained : one leading to an apex with a single or a few apical cells, and the other to an apex with a quiescent centre. The change of structure while applying a steady growth tensor indicates that development may involve a succession of discrete growth tensors.     

Root responses to legume plants integrate information on nitrogen availability and neighbour identity

Rhizobial symbiosis is known to increase the nitrogen availability in the rhizosphere of legumes. Therefore, it has been hypothesized that other plants’ roots should forage towards legume neighbours, but avoid non-legume neighbours. Yet, root distribution responding to legume plants as opposed to non-legumes has not yet been rigorously tested and might well be subject to integration of multiple environmental cues.In this study, wedevised an outdoor mesocosm experiment to examine root distributions of the two plant species Pilosella officinarum and Arenaria serpyllifolia in a two-factorial design. While one factor was ‘neighbour identity’, where plants were exposed to different legume or non-legume neighbours, the other factor was ‘nitrogen supply’. In the latter the nutrient-poor soil was supplemented with either nitrogen-free or with nitrogen-containing fertilizer.Unexpectedly, of all treatments that included a legume neighbour (eight different species or factor combinations), we found merely one case of root aggregation towards a legume neighbour (P. officinarum towards Medicago minima under nitrogen-fertilized conditions). In this very treatment, also P. officinarum root–shoot allocation was strongly increased, indicating that neighbour recognition is coupled with a contesting strategy.Considering the various response modes of the tested species towards the different legume and non-legume neighbours, we can conclude that roots integrate information on neighbour identity and resource availability in a complex manner. Especially the integration of neighbour identity in root decisions must be a vital aptitude for plants to cope with their complex biotic and abiotic environment in the field.     

Can landscape properties predict occurrence of grey-sided voles?

There has been a long-term decline in spring and fall numbers of Clethrionomys rufocanus in boreal Sweden in 1971–2005. Previous studies on permanent sampling plots in the centre of 2.5 × 2.5 km landscapes suggested that habitat fragmentation (sensu destruction) could have contributed to the decline. Therefore, we tested these findings in a field study and compared trapping results on the central sampling plots of landscapes with a low degree of fragmentation (LDF) and of “hot spot” type with trapping results in managed forest landscapes with a high degree of fragmentation (HDF). We predicted that C. rufocanus would be more common on the LDF plots. We used our permanent plots supplemented with a new sample of plots, mainly of the rare LDF type, inside or just outside the long-term study area. Very few voles were trapped on both plot types, and no difference was found. However, a subsequent pilot study with trapping in a national park with large areas of pristine, unfragmented forest yielded more voles than in the managed, more fragmented, areas. Consequently, the initial field study data and some other recent data were also re-analysed from a “local patch quality” perspective. This alternative approach revealed the positive importance of large focal patches of forest >60 years old and their content of old-growth (pine) forest (>100 years). Interestingly, at the landscape level, the frequency distribution of patches of forest >60 years old, old-growth (>100 years), and especially of old-growth pine forest (>100 years), relative to the properties of plots with C. rufocanus, suggested that there are few forest patches left that are suitable for C. rufocanus. Our current results suggest that habitat fragmentation cannot be excluded as a contributing cause to the long-term decline of C. rufocanus in boreal Sweden.     

Adrenergic responses and the Root effect in erythrocytes of freshwater fish

The effects of adrenergic-stimulation upon the oxygen-binding capacity of fish erythrocytes have been investigated. The oxygen capacity of rainbow trout, Oncorhynchus mykiss (Walbaum), erythrocytes was lowered by 44% on extracellular acidification (the so-called 'Root effect'). Addition of isoproterenol at 20° Ccaused an acid shift of the curve relating oxygen capacity to pH₀ by approximately 0.2 pH units, a value which was similar to the change in intracellular pH caused by adrenergic stimulation (Cossins & Kilbey Journal of Experimental Biology , 148 , 303–312, 1990). Moreover, when plotted as a function of pH_i, the curves for control and adrenalinstimulated erythrocytes were superimposable suggesting that the adrenergic shift in the Root curve was a result of the change in pH_i caused by activation of the adrenergic Na⁺/H⁺ exchanger.
A similarly large adrenergic shift in the Root curve was observed for pike, Esox lucius L., erythrocytes, though not for erythrocytes of carp, Cyprinus carpio L., and tench, Tinea tinea (L.). The pH for the mid-point of the Root effect in pike erythrocytes was distinctly more acid than for trout, but in both cases corresponded closely with the optimal pH for the adrenergic Na⁺/H⁺ exchange mechanism. This suggests a link between the functional characteristics of the exchanger and the oxygen-binding properties of haemoglobin.     

Relationship between the concentration of sugars in the roots and VA mycorrhizal infection

Summary The VA-infected wheat varieties showed an increase of total (Lozano var.) and reducing (Lozano and Pane vars.) sugars in their root extracts. However, no clear relationship between sugar concentration in the root and VA mycorrhizal infection level could be established.In addition, the VA mycorrhizal hosts sorghum, alfalfa, sunflower and maize, and non-host radish and cabbage plants were tested for sugar content in their root extracts after fifteen days of growth. Sugars present in the root extracts of these plants did not seem to be a decisive factor in plant susceptibility to VA infection.     

Monolithic Endocrown Vs. Hybrid Intraradicular Post/Core/Crown Restorations for Endodontically Treated Teeth; Cross-sectional Study

The gold standard for restoring Endodontically Treated Teeth (ETT) with successful clinical longevity requires having minimal invasive preparations and maximal tissue conservation. Many dentists still consider hybrid post/core/crown to be the first choice for restoring ETT. Endocrown is a viable alternative treatment modality to hybrid post/core/crown. This study aims to assess the proper judgment of dentists working in Riyadh, Saudi Arabia on the use of monolithic endocrown versus hybrid post/core/crown for restoring ETT. The IRB of Princess Nourah Bint Abdulrahman University (PNU) Institutional Review Board reviewed this study. The questionnaire was validated and electronically distributed. The participants were pre-informed that their responses are completely anonymous and used for professional purposes only. The questionnaire surveyed dentists working in Riyadh, Saudi Arabia, about their preference for different ETT restorative modalities at various clinical scenarios. Data were analyzed using One-way ANOVA and t-test. All P-values of < 0.05 were considered statistically significant. A total of 275 responses were collected; 61.45% were females and 38.55% males. 56% of them were general practitioners, while 16% were consultants. Prefabricated post/core was the most preferred technique among the participants (18.55%), followed by endocrown (12.36%), and lastly, cast post/core (8.73%). The amount of remaining tooth structure was the most influential in the treatment selection (30.18%), followed by the presence or absence of 1–2 mm ferrule (17.82%). Interocclusal space (12.36%) was the least influential factor. Endocrown recorded 63.27% as the most preferred line of treatment in case of insufficient inter-occlusal space. 40.36% preferred endocrown for patients with occlusal risk factors. The amount of the remaining tooth structure and the tooth position significantly affect the treatment options of the participants. Endocrown was the most preferred treatment modality for restoring ETT for patients with occlusal consideration.     

Cross-pathogenicity of Rhizoctonia solani strains on pasture legumes in pasture-crop rotations

In Australia, in the past, pasture legumes were rotated mainly with cereals, but increasingly these rotations now involve pasture legumes with a wider range of crops, including legumes. This increasing frequency of the leguminous host in the rotation system may be associated with increased root rots in legumes in the current pasture-crop rotations. The primary aim of this study was to see whether the pathogenicity on pasture legumes of strains of Rhizoctonia solani sourced from lupins and cereals (common crops in rotation with pastures) is associated with increased incidence of root rots in pasture legumes in the disease conducive sandy soils of the Mediterranean regions of southern Australia. The second aim was to determine sources of resistance among newly introduced pasture legumes to R. solani strains originating from rotational crops as this would reduce the impact of disease in the pasture phase. Fifteen pasture legume genotypes were assessed for their resistance/susceptibility to five different zymogram groups (ZG) of the root rot pathogen R. solani under glasshouse conditions. Of the R. solani groups tested, ZG1–5 and ZG1–4 (both known to be pathogenic on cereals and legumes) overall, caused the most severe root disease across the genotypes tested, significantly more than ZG6 (known to be pathogenic on legumes), in turn significantly >ZG4 (known to be pathogenic on legumes) which in turn was >ZG11 (known to be pathogenic on legumes including tropical species). Overall, Ornithopus sativus Brot. cvs Cadiz and Margurita, Trifolium michelianum Savi. cvs Paradana and Frontier and T. purpureum Loisel. cv. Electro showed a significant level of resistance to root rot caused by R. solani ZG11 (root disease scores ≤1.2 on a 1–3 scale where 3 = maximum disease severity) while O. sativus cvs Cadiz and Erica showed a significant level of resistance to root rot caused by R. solani ZG4 (scores ≤1.2). O. compressus L. cvs Charano and Frontier, O. sativus cv. Erica, and T. purpureum cv. Electro showed some useful resistance to root rot caused by R. solani ZG6 (scores ≤1.8). This is the first time that cvs Cadiz, Electro, Frontier, Margurita and Paradana have been recognised for their levels of resistance to root rot caused by R. solani ZG11; and similarly for cvs Cadiz and Erica against ZG4; and for cvs Charano, Erica, and Electro against ZG6. These genotypes with resistance may also serve as useful sources of resistance in pasture legume breeding programs and also could potentially be exploited directly into areas where other rotation crops are affected by these R. solani strains. None of the tested genotypes showed useful resistance to R. solani ZG1–4 (scores ≥2.0) or ZG1–5 (scores ≥2.5). This study demonstrates the relative potential of the various R. solani ZG strains, and particularly ZG1–4, ZG1–5, ZG4 and ZG6 to attack legume pastures and pose a significant threat to non-pasture crop species susceptible to these strains grown in rotation with these pasture legumes. Significantly, the cross-pathogenicity of these strains could result in the continuous build-up of inoculum of these strains that may seriously affect the productivity eventually of legumes in all rotations. In particular, when choosing pasture legumes as rotation crops, caution needs to be exercised so that the cultivars deployed are those with the best resistance to the R. solani ZGs most likely to be prevalent at the location.     

Rhizobium tropiciteu genes involved in specific uptake of Phaseolus vulgaris bean-exudate compounds

Rhizobium tropici nodulates and fixes nitrogen in bean. In the R. tropici strain CFN299 we identified and characterized teu genes (tropiciexudate uptake) induced by bean root exudates, localized by insertion of a promoter-less Tn5-gusA1 transposon. teu genes are present on a plasmid of around 185 kb that is conserved in all R. tropici strains. Proteins encoded by teu genes show similarity to ABC transporters, specifically to ribose transport proteins. No induction of the teu genes was obtained by treatment with root exudates from any of several other plants tested, with the exception of Macroptilium atropurpureum, which is also a host plant for R. tropici. It appears that the inducing compound is characteristic of bean and closely related legumes. It is present in root exudates, but not in seeds. This compound is removed, presumably by metabolism, from the exudates by the majority of bean-nodulating rhizobia (such as R. etli, R. leguminosarum bv. phaseoli and R.␣giardinii). The principal inducing compound has not been identified, but some induction was obtained using trigonelline. The CFN299 strain seems to have an additional uptake system, as no phenotype is observed in two different mutants. R. tropici strain CIAT899, on the other hand, must have only one uptake system, since a mutant bearing an insertion in the teu genes could not remove the compound from the exudates as efficiently as the wild type, and it showed diminished nodulation competitiveness. Received: 21 November 1997 / Accepted: 18 March 1998     

Influence of crop rotation and intercropping of cassava with legumes on VA mycorrhizal symbiosis of cassava

Summary In comparison to cassava grown in monoculture the root infection of cassava with vesicular-arbuscular mycorrhiza was increased by crop rotation with grain legumes in the field. This was also found when cassava was intercropped with legumes and fertilized. A possible specificity of mycorrhizal fungi to increase the yield of one species more than the other when grown in association, is discussed.