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C. Hasbun

Bio: C. Hasbun is an academic researcher. The author has contributed to research in topics: Chemical ecology & Subtropics. The author has an hindex of 4, co-authored 4 publications receiving 305 citations.

Papers
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Journal ArticleDOI
TL;DR: The results support other studies on Asian and African Piper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.
Abstract: Insecticidal and growth-reducing properties of extracts of 14 species of American neotropical Piperaceae were investigated by inclusion in diets of a polyphagous lepidopteran, the European corn borer,Ostrinia nubilalis. Nutritional indices suggested most extracts acted by postdigestive toxicity.Piper aduncum, P. tuberculatum, andP. decurrens were among the most active species and were subjected to bioassay-guided isolation of the active components. Dillapiol was isolated from the active fraction ofP. aduncum, piperlonguminine was isolated fromP. tuberculatum, and a novel neolignan fromP. decurrens. The results support other studies on Asian and AfricanPiper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.

178 citations

Journal ArticleDOI
TL;DR: Hirtin and various extracts from T. connaroides significantly reduced larval growth and consumption rates, as well as dietary utilization, indicating that these substances possess both behavioral effects and post-ingestive toxicity.

76 citations

Book ChapterDOI
TL;DR: It is suggested that chemical defenses are most important in areas of the tropics where soils are nutrient deficient (oligotrophic) and where loss of foliage to herbivory involves the loss of scarce plant macro- and micronutrients, which are more critical than replaceable carbohydrates.
Abstract: Biotic interactions in the tropics are intense and have led to the evolution of a great diversity of phytochemicals which act as deterrents to phytophagous insects. While the diversity of tropical forests and the phytochemicals they produce is well known, certain other features of the chemical ecology of these areas have also been described. An early review of alkaloid-bearing plants suggested that the foliar concentration of alkaloids was higher in tropical environments at lower latitudes and altitudes than in subtropical and temperate environments at higher latitudes and altitudes.1 Assignment of alkaloids to various toxicity classes suggested that tropical plants are also more biologically active as defense compounds than subtropical and temperate plants. Similar trends are seen even in crop plants such as maize, wherein resistance to borers and content of the insect resistance factor DIMBOA (2, 4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one) was inversely correlated to the altitude and latitude of origin of maize genotypes.2 Janzen3 suggested that chemical defenses are most important in areas of the tropics where soils are nutrient deficient (oligotrophic) and where loss of foliage to herbivory involves the loss of scarce plant macro- and micronutrients, which are more critical than replaceable carbohydrates. The forests of the Rio Negro were identified as an oligotrophic region which produces abundant amounts of secondary chemicals that probably contribute to the black waters.

53 citations

Journal ArticleDOI
TL;DR: The spiro-triterpenoid spirocaracolitone as mentioned in this paper was isolated from a newly described genus and species, Ruptiliocarpon caracolito Hammel and Zamora (Lepidobotryaceae), a tree from humid lowland tropical rainforest in Costa Rica.

6 citations

Journal ArticleDOI
TL;DR: In this paper, a set of nuclear and mitochondrial markers were used for the identification of a juvenile penguin stranded on the Pacific Ocean shores of El Salvador as a Magellanic penguin.
Abstract: Abstract. – In this study, the mitochondrial Cytochrome C Oxidase 1 gene, three nuclear microsatellite markers, and the MHC class II DRβ1 exon 2 were assessed for species-specific differences that would allow diagnostic identification of Spheniscus mendiculus, S. humboldti, and S. magellanicus specimens. Analyses of reference samples for these species revealed that genetic variation at these markers showed species-specific haplotypes and alleles that can provide positive evidence for species identification. Bayesian cluster analyses demonstrated high probability of assignment (>99%) for individual samples to their corresponding species. The set of nuclear and mitochondrial markers studied proved useful for the identification of a juvenile penguin stranded on the Pacific Ocean shores of El Salvador as a Magellanic penguin. The negative consequences of accidental captures of Magellanic penguins by fishermen and the relocation of wildlife through human intervention are discussed.

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Journal ArticleDOI
TL;DR: In recent years, the use of essential oils (EOs) derived from aromatic plants as low-risk insecticides has increased considerably owing to their popularity with organic growers and environmentally conscious consumers.
Abstract: In recent years, the use of essential oils (EOs) derived from aromatic plants as low-risk insecticides has increased considerably owing to their popularity with organic growers and environmentally conscious consumers. EOs are easily produced by steam distillation of plant material and contain many volatile, low-molecular-weight terpenes and phenolics. The major plant families from which EOs are extracted include Myrtaceae, Lauraceae, Lamiaceae, and Asteraceae. EOs have repellent, insecticidal, and growth-reducing effects on a variety of insects. They have been used effectively to control preharvest and postharvest phytophagous insects and as insect repellents for biting flies and for home and garden insects. The compounds exert their activities on insects through neurotoxic effects involving several mechanisms, notably through GABA, octopamine synapses, and the inhibition of acetylcholinesterase. With a few exceptions, their mammalian toxicity is low and environmental persistence is short. Registration has been the main bottleneck in putting new products on the market, but more EOs have been approved for use in the United States than elsewhere owing to reduced-risk processes for these materials.

859 citations

Journal ArticleDOI
TL;DR: The secondary metabolites isolated from Piper species for the period 1907 to June 1996 have been reviewed in this paper, where nearly six hundred chemical constituents belonging to different classes of bioactive compounds are listed together with their source(s) and references.

849 citations

Journal ArticleDOI
TL;DR: The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability.

641 citations

Journal ArticleDOI
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about concrete mechanical properties such as E-modulus and compressive strength.
Abstract: Natural Science Foundation of China[30000213, 30370160, 30670214]; National Basic Research Program of China (973 Program)[2009CB522300]; Chinese Academy of Sciences

372 citations

Journal ArticleDOI
TL;DR: The reduction in growth rate of T. castaneum larvae and S. zeamais adults was mainly due to a behavioural (feeding deterrent) action rather than to post-ingestive toxicity of the oil, and the essential oil had a weaker feeding deterrent action against E. rutaecarpa.

371 citations