The effect of seed source, light during germination, and cold-moist stratification on seed germination in three species of Echinacea for organic production

Organic production of one of the most popular botanical supplements, Echinacea, continues to expand in the U.S. Echinacea seeds typically show a high degree of dormancy that can be broken by ethephon or gibberelic acid (GA), but these methods are currently disallowed in organic production. In order to determine the efficacy of non-chemical seed treatments, we evaluated the effect of varying seed source and supplying light, with and without cold-moist stratification, on seed germination of the three most important medicinal species of Echinacea, E. angustifolia DC, E. purpurea (L) Moench, and E. pallida (Nutt.) Nutt. Treatments included cold-moist stratification under 24 h light, 24 h dark, and 16/8 h light/dark to break seed dormancy. We found that germination was greater in the E. purpurea and E. pallida seeds from a commercial organic seed source compared to a public germplasm source. When seeds were not cold-moist stratified, 16-24 h light increased germination in E. angustifolia only. Echinacea angustifolia, E. purpurea, and E. pallida seeds that were cold-moist stratified under 16-24 h of light for 4 wk had a significantly greater percentage and rate of germination compared to seeds germinated in the dark. Therefore, cold-moist stratification under light conditions is recommended as a method to break seed dormancy and increase germination rates in organic production of Echinacea.     

Phenology, damage and parasitoids of the apple leaf cutter Coenorhinus pauxillus (Germ.) (Col.: Attelabidae)

An outbreak on apple permitted a closer look at Coenorhinus pauxillus (Germar) (Col.: Attelabidae). The adult weevils emerge from mid-March onwards and attack the first unfolding leaves. Infested leaves drop when the larvae are in the 1^st or 2^nd instar, and it takes a further 4 weeks before the larvae are ready to pupate. Rearing of field-collected eggs and larvae is described. Leaf decomposition is an essential condition for pupation, as the fully-grown larvae do not leave their mine actively. Part of the population pupates more or less immediately and produces adult weevils in autumn. However, up to 70?% of the weevils remain in prolonged diapause; their pupation does not take place before the summer of the following year. Damage by the weevil involves not only the loss of leaves of flower clusters and shoots, but also feeding damage to young fruits. Two parasitoids were found. Observations indicate that 3?–?4 subsequently more abundant generations of Anaphes brachygaster Debauche (Hym.: Mymaridae) develop in eggs of C. pauxillus. Probles brevicornis Horstmann (Hym.: Ichneumonidae, Tersilochinae) emerges in May and oviposits in young weevil larvae on the tree. The parasitoid does not develop into a pupa until its host starts pupating. The outbreak of apple leaf cutter did not decline over three years, but did not spread into adjacent plantings.     

Antiplatelet and Anticoagulant Effects of Diterpenes Isolated from the Marine Alga,Dictyota menstrualis

Cardiovascular diseases represent a major cause of disability and death worldwide. Therapeutics are available, but they often have unsatisfactory results and may produce side effects. Alternative treatments based on the use of natural products have been extensively investigated, because of their low toxicity and side effects. Marine organisms are prime candidates for such products, as they are sources of numerous and complex substances with ecological and pharmacological effects. In this work, we investigated, through in vitro experiments, the effects of three diterpenes (pachydictyol A, isopachydictyol A and dichotomanol) from the Brazilian marine alga, Dictyota menstrualis, on platelet aggregation and plasma coagulation. Results showed that dichotomanol inhibited ADP- or collagen-induced aggregation of platelet-rich plasma (PRP), but failed to inhibit washed platelets (WP). In contrast, pachydictyol A and isopachydictyol A failed to inhibit the aggregation of PRP, but inhibited WP aggregation induced by collagen or thrombin. These diterpenes also inhibited coagulation analyzed by the prothrombin time and activated partial thromboplastin time and on commercial fibrinogen. Moreover, diterpenes inhibited the catalytic activity of thrombin. Theoretical studies using the Osiris Property Explorer software showed that diterpenes have low theoretical toxicity profiles and a drug-score similar to commercial anticoagulant drugs. In conclusion, these diterpenes are promising candidates for use in anticoagulant therapy, and this study also highlights the biotechnological potential of oceans and the importance of bioprospecting to develop medicines.     

Flour Protein Composition and Functional Properties of Transgenic Rye Lines Expressing HMW Subunit Genes of Wheat

Flours from nonsprouted (ns) kernels and dried sprouted (s) kernels of transgenic rye expressing HMW glutenin subunits (HMW‐GS) 1Dy10 (L10) or 1Dx5+1Dy10 (L5+10) from wheat were compared with flours from the corresponding wildtype rye (Lwt). The crude protein content of nonsprouted flours ranged from 9.2% (Lwt) to 10.4% (L5+10) and was lowered by ≈1% due to sprouting. Flour proteins were separated into albumins/globulins, prolamins, and glutelin subunits by a modified Osborne fractionation and into SDS‐soluble and insoluble fractions. Portions of the prolamin fractions were reduced in the same manner as glutelins. The different fractions were then characterized and quantified by RP‐HPLC on C₈ silica gel. The proportion of albumins/globulins did not significantly differ between transgenic lines and wildtype. The proportions of alcohol‐insoluble glutelins and SDS‐insoluble proteins drastically increased in transgenic rye due to a shift of HMW and γ‐75k secalins into the polymeric fractions. Significant differences in the proportion of highly polymeric proteins between nonsprouted and sprouted flours could not be detected. The quantitative data demonstrated that the expression of HMW‐GS led to a higher degree of polymerization of storage proteins in rye flour. The HMW‐GS combination 1Dx5+1Dy10 showed stronger effects than 1Dy10 alone. The analyzed flours contained two HMW secalins (R1, R2), whose amino acid compositions were closely related to those of 1Dy10 and 1Dx5, respectively. The amounts of R1 in Lwt flours determined by RP‐HPLC were 221 mg (ns) and 186 mg (s) per 100 g and those of R2 were 344 mg (ns) and 298 mg (s), respectively. These amounts increased to 240 mg (ns)/201 mg (s) (R1) and 479 mg (ns)/432 mg (s) (R2) in L10 flours. In L5+10 flours, the amount of R1 decreased to 150 mg (ns)/132 mg (s) while R2 increased to 432 mg (ns)/338 mg (s). The amount of HMW‐GS 1Dy10 was almost the same as that of R2 in L10 flours but was strongly increased in L5+10 flour (633 mg [ns]/538 mg [s]). HMW‐GS 1Dx5 was, by far, the major subunit in L5+10 flours (987 mg 7[ns]/896 mg [s]). The summarized amounts of all HMW subunits increased from ≈0.5 g (Lwt) to ≈1.1 g (L10) and ≈2.0 g (L5+10). Thus only L10 flours were similar to wheat flours in HMW subunit content. The baking performance of L10 flour determined by a microbaking test was improved compared with Lwt flour, whereas L5x10 flour showed very poor properties obviously due to the strongly increased proportion of highly cross‐linked glutelins. The breadmaking quality of flours from 1Dy10 seeds and wildtype seeds was reduced by the same degree when flours from sprouted seeds were analyzed.     

Mechanical cleaning and prescribed burning for recruiting commercial tree regeneration in a Bolivian dry forest

A critical component of sustainable forest management is the regeneration of commercially valuable tree species. Mechanical cleaning with machetes and chainsaws, prescribed burning, and a combination of both treatments were applied to recently-created logging gaps in a Bolivian dry forest to evaluate their impact on the natural regeneration of commercial tree species and on control of competing vegetation. The three treatments and an untreated control were applied to logging gaps during the dry season of 1998 and replicated ten times. Eight months following burning, the density of commercial tree regeneration in gaps did not differ statistically among treatments. Relative height growth of total commercial regeneration also did not differ among treatments, although it did vary by species. Reduction in competing vegetation following the application of site preparation treatments was significantly higher, but competing plant cover was beginning to converge among treatments after eight months. Despite better control of competing vegetation, early recruitment and growth responses to burning and cleaning of vegetation in logging gaps do not appear to justify application of these treatments in this forest, especially considering their high costs.     

Breeding apomictic bahiagrass (Paspalum notatum Flügge) with improved turf traits

The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H²) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H² indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation.     

Evaluation of marine brown algae and sponges from Brazil as anticoagulant and antiplatelet products

The ischemic disorders, in which platelet aggregation and blood coagulation are involved, represent a major cause of disability and death worldwide. The antithrombotic therapy has unsatisfactory performance and may produce side effects. So, there is a need to seek molecules with antithrombotic properties. Marine organisms produce substances with different well defined ecological functions. Moreover, some of these molecules also exhibit pharmacological properties such as antiviral, anticancer, antiophidic and anticoagulant properties. The aim of this study was to evaluate, through in vitro tests, the effect of two extracts of brown algae and ten marine sponges from Brazil on platelet aggregation and blood coagulation. Our results revealed that most of the extracts were capable of inhibiting platelet aggregation and clotting measured by plasma recalcification tests, prothrombin time, activated partial thromboplastin time, and fibrinogenolytic activity. On the other hand, five of ten species of sponges induced platelet aggregation. Thus, the marine organisms studied here may have molecules with antithrombotic properties, presenting biotechnological potential to antithrombotic therapy. Further chemical investigation should be conducted on the active species to discover useful molecules for the development of new drugs to treat clotting disorders.     

Tick saliva induces regulatory dendritic cells: MAP-kinases and Toll-like receptor-2 expression as potential targets

Ticks (Acari: Ixodidae) are bloodsucking ectoparasitic arthropods of human and veterinary medical importance. Tick saliva has been shown to contain a wide range of bioactive molecules with vasodilatory, antihemostatic, and immunomodulatory activities. We have previously demonstrated that saliva from Rhipicephalus sanguineus ticks inhibits the maturation of dendritic cells (DCs) stimulated with LPS. Here we examined the mechanism of this immune subversion, evaluating the effect of tick saliva on Toll-like receptor (TLR)-4 signalling pathway in bone marrow-derived DCs. We demonstrated that R. sanguineus tick saliva impairs maturation of DCs stimulated with LPS, a TLR-4 ligand, leading to increased production of interleukin (IL)-10 and reduced synthesis of IL-12p70 and TNF-α. The immunomodulatory effect of the tick saliva on the production of pro-inflammatory cytokines by DCs stimulated with LPS was associated with the observation that tick saliva inhibits the activation of the ERK 1/2 and p38 MAP kinases. These effects were independent of the expression of TLR-4 on the surface of DCs. Additionally, saliva-treated DCs also presented a similar pattern of cytokine modulation in response to other TLR ligands. Since the recent literature reports that several parasites evade immune responses through TLR-2-mediated production of IL-10, we evaluated the effect of tick saliva on the percentage of TLR-2⁺ DCs stimulated with the TLR-2 ligand lipoteicoic acid (LTA). The data showed that the population of DCs expressing TLR-2 was significantly increased in DCs treated with LTA plus saliva. In addition, tick saliva alone increased the expression of TLR-2 in a dose- and time-dependent manner. Our data suggest that tick saliva induces regulatory DCs, which secrete IL-10 and low levels of IL-12 and TNF-α when stimulated by TLR ligands. Such regulatory DCs are associated with expression of TLR-2 and inhibition of ERK and p38, which promotes the production of IL-10 and thus down-modulates the host's immune response, possibly favouring susceptibility to tick infestations.     

Landscape-scale patterns and drivers of novel mammal communities in a human-modified protected area

Landscape Ecology - The role of protected areas as biodiversity repositories has become increasingly important in face of increased deforestation. By adding free-living exotic mammals, removing...