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1.
Kalina Bermúdez-Torres Jorge Martínez Herrera Rodolfo Figueroa Brito Michael Wink Luc Legal 《BioControl》2009,54(3):459-466
Bitter lupins (Lupinus spp.) are not used as a protein source because of their toxicity. However, they may have alternative uses as potential sources
of natural insecticides. Quinolizidine alkaloids (QA) of three Mexican Lupinus species (Fabaceae): L. montanus (HBK),
L. stipulatus (Agardh) and L. aschenbornii (Schauer), were analyzed by capillary Gas Chromatography-Mass Spectrometry. Sparteine was found in high amounts in both L. montanus and L. aschenbornii while the major alkaloids in L. stipulatus extract were aphylline and an epiaphylline-like compound. Alkaloid extracts were tested for their insecticidal activity using
larvae of the Fall Armyworm, Spodoptera frugiperda (Smith); (Lepidoptera, Noctuidae) as a model pest. We compared LD50 values and mean weight of caterpillars fed with alkaloid extracts of the three species studied with those of sparteine, a
widespread QA found in various lupin species. Extracts of L. montanus and L. aschenbornii were found to be as effective as sparteine and extracts L. stipulatus were found to be the most toxic against the larvae of S. frugiperda. This suggests that the various QA act differently on caterpillars, and could be used to control Spodoptera populations.
相似文献
Kalina Bermúdez-TorresEmail: |
2.
A total of eight strains of bacteria were isolated from the root nodule of Vicia faba on the selective media of Rhizobium. Two of these strains produced phenotypically distinct mucoid colonies (one slow growing and the other fast growing) and
were examined using a polyphasic approach for taxonomic identification. The two strains (MTCC 7405 and MTCC 7406) turned out
to be new strains of biovar 1 Agrobacterium rather than Rhizobium, as they showed growth on alkaline medium as well as on 2% NaCl and neither catabolized lactose as the carbon source nor
oxidized Tween-80. The distinctness between the two strains was marked with respect to their growth on dextrose and the production
of lysine dihydrolase, ornithine decarboxylase and DNA G + C content. 16S rDNA sequencing and their comparison with the 16S
rDNA sequences of previously described agrobacteria as well as rhizobia strains confirmed the novelty of the two strains.
Both of the strains clustered with strains of Agrobacterium tumefaciens in the 16S rDNA-based phylogenetic tree. The phenotypic and biochemical properties of the two strains differed from those
of the recognized biovar of A. tumefaciens. It is proposed that the strains MTCC 7405 and MTCC 7406 be classified as novel biovar of the species A. tumefaciens (Type strains MTCC 7405 = DQ383275 and MTCC 7406 = DQ383276).
相似文献
Bhupendra N. TiwaryEmail: |
3.
Mycena aphanes and Mycena exilis, belonging to section Filipedes and section Polyadelphia, are proposed as new species. They are described and illustrated and compared to other species in the two sections. Mycena aphanes is a strikingly characteristic Mycena with fulvous or yellowish brown colours of both pileus and stipe. Mycena exilis is characterized by its occurrence on fallen Salix leaves, a pale brown pileus, occasionally with a pale pink tinge, narrowly adnate lamellae, four-spored basidia, and the
presence of clamp connections.
相似文献
Gro GuldenEmail: |
4.
Karen E. Chambers Ryan McDaniell Jeremy D. Raincrow Maya Deshmukh Peter F. Stadler 《Theorie in den Biowissenschaften》2009,128(2):109-120
Large-scale—even genome-wide—duplications have repeatedly been invoked as an explanation for major radiations. Teleosts, the
most species-rich vertebrate clade, underwent a “fish-specific genome duplication” (FSGD) that is shared by most ray-finned
fish lineages. We investigate here the Hox complement of the goldeye (Hiodon alosoides), a representative of Osteoglossomorpha, the most basal teleostean clade. An extensive PCR survey reveals that goldeye has
at least eight Hox clusters, indicating a duplicated genome compared to basal actinopterygians. The possession of duplicated Hox clusters is uncoupled to species richness. The Hox system of the goldeye is substantially different from that of other teleost lineages, having retained several duplicates
of Hox genes for which crown teleosts have lost at least one copy. A detailed analysis of the PCR fragments as well as full length
sequences of two HoxA13 paralogs, and HoxA10 and HoxC4 genes places the duplication event close in time to the divergence of Osteoglossomorpha and crown teleosts. The data are
consistent with—but do not conclusively prove—that Osteoglossomorpha shares the FSGD.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Chi-hua ChiuEmail: |
5.
The interconnection network is one of the key architectural components in any parallel computer. The distribution of the traffic
injected into the network is among the factors that greatly influences network performance. The uniform traffic pattern has
been adopted in many existing network performance evaluation studies due to the tractability of the resulting analytical modelling
approach. However, many real applications exhibit non-uniform traffic patterns such as hot-spot traffic. K-ary n-cubes have been the mostly widely used in the implementation of practical parallel systems. Extensive research studies have
been conducted on the performance modelling and evaluation of these networks. Nonetheless, most of these studies have been
confined to uniform traffic distributions and have been based on software simulation. The present paper proposes a new stochastic
model to predict message latency in k-ary
n-cubes with deterministic routing in the presence of hot-spot traffic. The model has been validated through simulation experiments
and has shown a close agreement with simulation results.
相似文献
Geyong MinEmail: |
6.
7.
Richard J. Robins Roland Molinié Renata A. Kwiecień Piotr Paneth Jacques Lebreton Trixie A. Bartholomeusz Albrecht Roscher Birgit Dräger Anna-Carolin Meier François Mesnard 《Phytochemistry Reviews》2007,6(1):51-63
The reaction of N-demethylation plays an important role in the degradation of some alkaloids in a number of organisms. This review presents
how our understanding of the N-demethylation of nicotine in plants has been improved through studies in cell cultures of Nicotiana plumbaginifolia and N. glutinosa using a variety of isotopic techniques. The overall aim is to understand how metabolism recycles the alkaloid skeleton, both
in terms of the metabolic route(s) exploited and the reaction mechanisms of the enzymes involved. The former has been approached
using high-resolution 2-dimensional NMR and GC-MS methods; the latter by determining kinetic isotope effects and modelling
the potential reaction steps. It appears that the mechanism for nicotine demethylation in plants is similar to but has significant
differences from that described for mammals and Pseudomonas bacteria. These differences are discussed.
相似文献
Richard J. RobinsEmail: |
8.
Antibodies are very often used as specific cell and/or tissue markers. An example of this is anti-horseradish peroxidase (HRP),
an antibody raised against a plant glycoprotein, which was shown some twenty-five years ago to specifically stain neural tissue
in an animal, Drosophila melanogaster. This peculiar finding was later expanded to other invertebrate species including Caenorhabditis elegans, which were also shown to bear anti-HRP epitopes. Initial experiments indicated that the epitopes recognised by anti-HRP
in invertebrates are of carbohydrate nature. Indeed, more recent experiments have characterised relevant core α1-3-fucosylated
N-glycan structures that act as epitopes in various model and parasitic organisms. Moreover, a number of enzymes required
for the synthesis of such structures have been identified. Over the years, medically-relevant roles of these structures have
become apparent as regards allergenicity and immunoregulation. Although major advances have been made in understanding of
the underlying mechanisms and structures related to the anti-HRP epitope, the in vivo role of the relevant epitopes in neural and other tissues is yet to be resolved. Current understanding of the anti-HRP epitopes
synthesis and their relevance is discussed and elaborated.
相似文献
Katharina PaschingerEmail: |
9.
Brad E. Erisman Jorge A. Rosales-Casián Philip A. Hastings 《Environmental Biology of Fishes》2008,82(1):23-33
The sexual pattern and sexual development of the leopard grouper, Mycteroperca rosacea, were investigated from 483 specimens collected from the Gulf of California, Mexico. Histological and population data indicated
a gonochoric sexual pattern. Some juveniles passed through an immature bisexual phase of gonadal development, but no evidence
of post-maturational sex change was found. The immature bisexual phase is believed to be associated only with male development.
The size distribution and size at sexual maturity were similar for both males and females. In accordance with predictions
of the size-advantage model, the gonochoric sexual pattern of M. rosacea is likely influenced by its group-spawning mating system.
相似文献
Brad E. ErismanEmail: |
10.
11.
We tested the pathogenicity of 18 Metarhizium anisopliae (Metschn.) Sorokin isolates and 22 Beauveria bassiana (Balsamo) Vuillemin isolates against Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) larvae and adults. The efficacy of the most virulent isolate—M. anisopliae K—was evaluated in containers with a concrete bottom covered with wood shavings, under simulated poultry house conditions.
Application of conidia of this isolate to the shavings or directly to the concrete bottom reduced the yield of larvae in 8–15
time compared with the control. In another test, the mortality of mature larvae placed on previously inoculated shavings or
bottom reached 80–90% within 14 days, compared with 14% in the control. The residual activity of conidia kept at 28°C retained
its initial level during 14 days post-inoculation, but declined after three weeks. Based on our data M. anisopliae has considerable potential for the control of A. diaperinus.
相似文献
Michael SamishEmail: Email: |
12.
Geoffrey R. Dixon 《Journal of Plant Growth Regulation》2009,28(3):212-228
Plasmodiophora brassicae Wor. is viewed in this article from the standpoint of a highly evolved and successful organism, well fitted for the ecological
niche that it occupies. Physical, chemical, and biological components of the soil environment are discussed in relation to
their effects on the survival, growth, and reproduction of this microbe. It is evident that P. brassicae is well equipped by virtue of its robust resting spores for survival through many seasonal cycles. Germination is probably
triggered as a result of signals initiated by root exudates. The resultant motile zoospore moves rapidly to the root hair
surface and penetration and colonization follow. The short period between germination and penetration is one of greatest vulnerability
for P. brassicae. In this phase survival is affected at the very least by soil texture and structure; its moisture; pH; calcium, boron, and
nitrogen content; and the presence of active microbial antagonists. These factors influence the inoculum potential (sensu Garrett, 1956) and its viability and invasive capacity. There is evidence that these effects may also influence differentially
the survival of some physiologic races of P. brassicae. Considering the interaction of P. brassicae with the soil environment from the perspective of its biological fitness is an unusual approach; most authors consider only
the opportunities to destroy this organism. The approach adopted here is borne of several decades spent studying P. brassicae and the respect that has been engendered for it as a biological entity. This review stops at the point of penetration, although
some of the implications of the environment for successful colonization are included because they form a continuum. Interactions
with the molecular and biochemical cellular environment are considered in other sections in this special edition.
相似文献
Geoffrey R. DixonEmail: |
13.
Nothofagus pumilio (Poepp et Endl.) Krasser is the dominant subalpine tree in the southern Andes between 36°S and 55°S. Increment cores from a N. pumilio stand growing near the Ameghino Glacier (50°25S, 73°10W), southern Patagonian Andes, Argentina, contain significant numbers of intra-annual bands (or false rings) which have not been previously described for this species. These samples are used to develop a well-replicated ring-width chronology and a record of intra-annual bands from AD 1760 to 1997. Annual variations in radial growth of N. pumilio at this site are negatively correlated with spring–summer temperatures and positively with spring precipitation. The formation of intra-annual bands appears to be a response to anomalously dry-warm springs followed by wet-warm late summers. Intra-annual bands may occur in up to 95% of the sampled trees in a given year, and the percentage of trees affected was used as an indication of the strength of the forcing event. Narrow rings occurred in the years following intra-annual band formation, reflecting the lagged effect of unfavorable climatic conditions on tree growth during the subsequent growing season. Intra-annual bands occurred more frequently in the twentieth century than the late eighteenth and nineteenth centuries. This contrasting pattern seems to be a response to the combination of a long-term warming trend and a significant decrease in precipitation recorded during the last 100 years in this region of southern South America.
相似文献
Mariano MasiokasEmail: |
14.
This paper reports results from monitoring atmospheric pollen in Salitral de la Vidriera, an area of natural vegetation near Bahía Blanca city (East Central Argentina). Sampling was carried out weekly during January
to December 2003 and May 2005 to April 2006 using a volumetric impact sampler. Observations of flowering in the field were
carried out at the same time as the aerial sampling. During this period, 43 pollen types were identified; most of these correspond
to pollen grains from either herbaceous or shrubby vegetation typical of the study area, for example Amaranthus, Brassicaceae, Centaurea, Poaceae, Chenopodiaceae, Urticaceae, some Asteraceae, and Condalia microphylla. This study on the atmosphere of Salitral de la Vidriera allowed us to identify the components of the vegetation type dominant in the area, namely a shrubby halophytic steppe. A
well represented family, for example Chenopodiaceae, could, under appropriate weather conditions, be an important contributor
of pollen to Bahía Blanca.
相似文献
María Gabriela MurrayEmail: |
15.
Five constant temperatures between 14 and 30°C were used to evaluate their effect on the development time and adult emergence
of five Trichogramma species found parasitizing eggs of the velvetbean caterpillar Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) on soybeans in subtropical Southern Brazil. Host eggs were parasitized at 20°C and then transferred
to the study temperatures to follow development and emergence of parasitoids. All five species were able to develop and emerge
within the range of temperatures evaluated, and the effect of temperature on development rates could be described by linear
regression. Trichogramma acacioi Brun, Moraes & Soares and T. rojasi Nagaraja & Nagarkatti were the most cold-tolerant species, with lower threshold temperatures of 8.1 ± 0.16°C and 9.2 ± 0.16°C,
respectively. Trichogramma atopovirilia Oatman & Platner was the least cold-adapted species, with a lower threshold of 10.2 ± 0.13°C. Degree-day accumulation ranged
from 153.8 DD for T. atopovirilia to 190.7 DD for T. acacioi. Adult emergence was higher than 90% for T. atopovirilia and T. pretiosum at all temperatures, whereas T. lasallei Pinto emergence dropped to 71.3% at 14°C and to 58.3% at 26°C, both significantly lower than the emergence of T. pretiosum and T. atopovirilia. Significantly less T. acacioi adults emerged at 30°C than either T. pretiosum or T. atopovirilia. The sex-ratio was not affected within the range of temperatures studied, and varied from 0.65 to 0.88 (female/(male + female)).
Differences among Trichogramma spp. densities in the field can be attributed to slower development rates and/or reduced emergence of adults, both at low
and high temperatures.
相似文献
Luís A. FoersterEmail: |
16.
Duraisamy Saravanakumar Nallathambi Lavanya Kannappan Muthumeena Thiruvengadam Raguchander Ramasamy Samiyappan 《BioControl》2009,54(2):273-286
Plant growth-promoting rhizobacterial (PGPR) strains were isolated from different agro-ecosystems of Tamil Nadu, India, and
were tested for their efficacy against the sheath rot pathogen Sarocladium oryzae under in vitro, glasshouse and field conditions. Vigour and a relative performance index (RPI) were used to assay the growth
promotion and antagonistic activity of Pseudomonas strains against S. oryzae under in vitro conditions. The results revealed the significant performance by strains Pf1, TDK1 and PY15 compared to other
strains. Further, the combination of Pseudomonas strains Pf1, TDK1 and PY15 was more effective in reducing sheath rot disease in rice plants compared to individual strains
under glasshouse and field conditions. Quantitative and native polyacrylamide gel electrophoresis (PAGE) analysis of peroxidase
(PO), polyphenol oxidase (PPO) and chitinase activity in rice plants showed an increased accumulation of defence enzymes in
the treatment with a combination of Pf1, TDK1 and PY15 compared to the treatment with individual strains and untreated controls.
The present study revealed the probable influence of antagonism, plant growth promotion and induced systemic resistance (ISR)
by the mixture of Pseudomonas bioformulations in enhancing the disease resistance in rice plants against sheath rot disease.
相似文献
Duraisamy SaravanakumarEmail: |
17.
M. Irfan-Ullah Giriraj Amarnath M. S. R. Murthy A. Townsend Peterson 《Biodiversity and Conservation》2007,16(6):1917-1925
Aglaia bourdillonii is a plant narrowly endemic to the southern portion of the Western Ghats (WG), in peninsular India. To understand its ecological
and geographic distribution, we used ecological niche modeling (ENM) based on detailed distributional information recently
gathered, in relation to detailed climatic data sets. The ENMs successfully reconstructed key features of the species’ geographic
distribution, focusing almost entirely on the southern WG. Much of the species’ distributional potential is already under
protection, but our analysis allows identification of key zones for additional protection, all of which are adjacent to existing
protected areas. ENM provides a useful tool for understanding the natural history of such rare and endangered species.
相似文献
M. Irfan-UllahEmail: Email: |
18.
Tomato is the most important vegetable crop in Spain. The mirid bug Nesidiocoris tenuis (Reuter) commonly appears in large numbers in protected and open-air tomato crops where little or no broad-spectrum insecticides
are used. Nesidiocoris tenuis is known to be a predator of whiteflies, thrips and several other pest species. However, it is also considered a pest because
it can feed on tomato plants, causing necrotic rings on stems and flowers and punctures in fruits. Our objectives were to
evaluate predation by N. tenuis on sweetpotato whitefly Bemisia tabaci Gennadius under greenhouse conditions and establish its relationship to N. tenuis feeding on tomato. Two different release rates of N. tenuis were compared with an untreated control (0, 1 and 4 N. tenuis plant−1) in cages of 8 m2. Significant reductions of greater than 90% of the whitefly population and correspondingly high numbers of N. tenuis were observed with both release rates. Regression analysis showed that necrotic rings on foliage caused by N. tenuis were best explained by the ratio of B. tabaci nymphs:N. tenuis as predicted by the equation y = 15.086x − 0.6359.
相似文献
Alberto UrbanejaEmail: |
19.
The recent sequencing of the first tree genome, that of the black cottonwood (Populus trichocarpa), opens a new chapter in tree functional genomics. While the completion of the genome is a milestone, mobilizing this significant
resource for better understanding the growth and development of woody perennials will be an even greater undertaking in the
years to come. In other model organisms, a critical tool for high-throughput analysis of gene function has been the generation
of large mutagenized populations. Some mutagenesis technologies and approaches cannot be applied to trees because of their
typically outcrossing breeding systems, high heterozygosity, large body size, and delayed flowering. In contrast, gene-tagging
approaches that use insertional mutagenesis to create dominant phenotypes are ideally suited for trees and, especially, Populus. Both activation tagging and enhancer trap programs have been successful in identifying new genes important to tree development.
The generation of genome-wide insertional mutant populations, which provide direct functional links between genes and phenotypes,
should help to integrate in silico analyses of gene and protein expression, association studies of natural genetic polymorphism, and phenotypic analyses of
adaptation and development.
相似文献
Victor BusovEmail: |