João Gomes da Costa

Aphid antixenosis in cotton is activated by the natural plant defence elicitor cis-jasmone

Upon insect herbivory, plants can release blends of volatile organic compounds (VOCs) that modify herbivore and natural enemy behaviour. We have shown recently that cotton, Gossypium hirsutum, emits a blend of defence VOCs that repels the cotton aphid, Aphis gossypii, upon herbivory by this notorious crop pest, including (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT). In this study, we investigated changes in the defence VOC profile of G. hirsutum induced by the naturally-occurring plant elicitor cis-jasmone (CJ) and whether these changes modify the behaviour of A. gossypii. In four-arm olfactometer assays, VOCs from untreated plants were significantly attractive (P<0.05), whilst VOCs from CJ-treated plants were significantly repellent (P<0.05). The VOCs induced by CJ appeared to comprise (Z)-3-hexenyl acetate, DMNT, methyl salicylate and TMTT. In quantitative VOC collection studies, sustained release of DMNT and TMTT was observed in CJ-treated plants over a period of five days, with levels becoming statistically significantly higher than for control treated plants on the fifth day in most cases. Despite earlier indications, no statistically significant differences were observed in levels of (Z)-3-hexenyl acetate or methyl salicylate between CJ and control treatments on any day. Furthermore, DMNT and TMTT emissions from CJ-treated plants were further enhanced by subsequent addition of A. gossypii. CJ treatment induced statistically significantly higher DMNT and TMTT expression levels as early as day three, when A. gossypii was present. The results in this study show that CJ can induce the production of A. gossypii-induced VOCs from G. hirsutum, with potential for deployment in novel crop protection strategies.

Identification of Semiochemicals Released by Cotton, Gossypium hirsutum, Upon Infestation by the Cotton Aphid, Aphis gossypii

The cotton aphid, Aphis gossypii (Homoptera: Aphididae), is increasing in importance as a pest worldwide since the introduction of Bt-cotton, which controls lepidopteran but not homopteran pests. The chemical ecology of interactions between cotton, Gossypium hirsutum (Malvaceae), A. gossypii, and the predatory lacewing Chrysoperla lucasina (Neuroptera: Chrysopidae), was investigated with a view to providing new pest management strategies. Behavioral tests using a four-arm (Pettersson) olfactometer showed that alate A. gossypii spent significantly more time in the presence of odor from uninfested cotton seedlings compared to clean air, but significantly less time in the presence of odor from A. gossypii infested plants. A. gossypii also spent significantly more time in the presence of headspace samples of volatile organic compounds (VOCs) obtained from uninfested cotton seedlings, but significantly less time with those from A. gossypii infested plants. VOCs from uninfested and A. gossypii infested cotton seedlings were analyzed by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS), leading to the identification of (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate, and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), which were produced in larger amounts from A. gossypii infested plants compared to uninfested plants. In behavioral tests, A. gossypii spent significantly more time in the control (solvent) arms when presented with a synthetic blend of these four compounds, with and without the presence of VOCs from uninfested cotton. Coupled GC-electroantennogram (EAG) recordings with the lacewing C. lucasina showed significant antennal responses to VOCs from A. gossypii infested cotton, suggesting they have a role in indirect defense and indicating a likely behavioral role for these compounds for the predator as well as the aphid.

Estimativas de repetibilidade de alguns caracteres de produção em mangueira

The objective of this papers was to estimate the repeatability coefficient of the total number of fruit per plant (TNF), production of fruit per plant (PFP) and average fruit weight (AWF), while the number of measures that should be performed for an efficient selection of the genotypes under evaluation were determined. Analysis were made using principal components. The estimates of the repeatability were of: 0.51; 0.53 and 0.81, associated to the determination coefficients (R2) of 80.44%, 81.60% and 94.41, respectively, for TNF, PFP and WMF. The estimate of the repeatability coefficient of the WMF demonstrated high regularity at the superiority of the individuals from one cycle to another, so the evaluation of three cycles was enough to predict the individual real value with R2 above 90%. In spite of the traits TNF and PFP have environmental influence, four mensurations allow to obtain R2 about 80%.

Biologia floral e sistema de reprodução de Annona squamosa L. (Annonaceae) na região de Petrolina-PE

Aspects of pollination biology and reproductive system of Annona squamosa L. were studied in Petrolina-PE, Northeastern Brazil, from June 1999 to February 2000, from 6:00 a.m. to 6:00 p.m. The flowers of A. squamosa are hermaphrodite, axillary, with fleshy calyx and corolla forming a floral camera which serves as a shelter, food source and mating place for visitors. The flowers also show light color petals, produce strong and bad odors. The anthesis takes place around 5:00 p.m., the flowers last for approximately two days, and show female phase in the first twenty hours and male phase in the following twenty hours, characterizing dichogamy. Carpophilus hemipterus, Carpophilus sp and Haptoncus ochraceus (Nitidulidae) are the main flower visitors and according to frequency, time and behavior, are considered pollinators of this species. The species is self-compatible, however the germination tests indicated that seeds from cross-pollination show higher viability than seeds from geitonogamy.

Similaridade genética de acessos de mangueira de diferentes origens geográficas avaliadas por marcadores AFLP

ABSTRACT - The genetic relationship among 105 mango accessions of different geographic origins of the Embrapa germplasmcollection was estimated based on AFLP marker in order to orient breeding and management of genetic resource activities of thisspecies to the Brazilian Semi-Arid region. Two additional accessions of other species of the Mangifera genus were also included asoutgroup. The DNA of the accessions was extracted according to the CTAB protocol, the AFLP reactions were performed to EcoRI/MseI primers and the polymorphic bands analyzed to built a phenogram based on the Jaccard similarity coefficient. A hundred andfifty-seven and fifty-four polymorphic and monomorphic bands, respectively, were obtained from 13 AFLP primer combinations. Thephenogram cophenetic value was estimated in 0.81. Five groups were observed: 1) Amrapali, Malika, Embrapa-CPAC hybrids andsome American varieties forming a group, 2) other built, predominantly, by American varieties, with some inclusions of South Af ricanand Brazilian hybrids, 3) a large group composed by Brazilian accessions, with some inclusion of Australian, Indian and Americanaccessions, 4) a group with some accessions of Espada, Rosa and others of different origins, and 5) a group formed by M. foetida andM. similis. Carabao and Manilla presented the largest similarity, 97%. The studied accessions presented similarity greater than 51%,suggesting a high genetic variability of the studied mango germplasm collection.Index terms : Mangifera indica , diversity, mango germplasm.

Cocos nucifera Linn. (Palmae) husk fiber ethanolic extract: antioxidant capacity and electrochemical investigation.

The present study aims to determine the antioxidant capacity of the ethanolic extracts of husk fiber of four coconut (Cocos nucifera L.) varieties (yellow dwarf, green dwarf, giant and hybrid) and to evaluate the electrochemical behavior of these extracts on a glassy carbon electrode and on a modified glassy carbon electrode. The highest values of total phenolic content were obtained for the hybrid (531 ± 24 mg GAE g(-1) dry extract) and yellow dwarf (501 ± 29 mg GAE g(-1) dry extract) varieties and the lowest was for the green dwarf variety with 58 ± 9 mg GAE g(-1) dry extract. The ability of the extracts to scavenge DPPH˙ radicals was in the order of giant > yellow dwarf > hybrid > green dwarf and the IC50 values varied from 8.6 to 55.9 μg mL(-1). All varieties showed reducing potential by the use of FRAP and CUPRAC methods, with the lowest performance obtained for the green dwarf variety. Additionally, through the use of mimetic biomembranes, ethanolic extracts of coconut husk were shown to protect lipids against oxidative damage independent of the variety. The main antioxidants identified in the extract of yellow dwarf variety by UPLC-MS were quercetin and catechin. Cyclic voltammetric studies of the ethanolic extracts on glassy carbon electrode confirmed the presence of easily oxidized compounds, and the high antioxidant capacity of the varieties. This capacity was expressed as mg quercetin equivalents g(-1) dry extract and ranged from 25.9 up to 53.5 mg QE g(-1). A poly-xanthurenic acid (poly-Xa)/multi-walled carbon nanotube (MWCNT) / glassy carbon modified electrode (poly-Xa/MWCNT/GCE) was used for this purpose. Our findings suggest that these extracts are potentially important antioxidant supplements for the everyday human diet, pharmaceutical and cosmetic industries, thereby aggregating value to the enormous amount of waste from the coconut industry, mostly used for burning purposes.

Antioxidant Capacity, Physicochemical and Floral Characterization of Honeys from the Northeast of Brazil

The aim of this work was to evaluate floral origin, physicochemical quality and antioxidant capacity of 15 honey samples, from a semi-arid region in the northeast of Brazil and to correlate data with color and total phenolic content (TPC). A predominance of amber color was observed. The majority of samples were classified as polifloral and only two samples (the light yellow ones) were monofloral. TPC values ranged from 27.0 to 92.7 mg GAE 100 g -1 of honey, being higher in darker samples. All samples had ability to scavenge DPPH  radicals and showed reducing potential analyzed by FRAP and CUPRAC methods, with the highest performance obtained in darker samples. TPC shows good positive correlations (p<0.05) with the methods used to evaluate antioxidant capacity. Significant correlations (p<0.01) between color and TPC (0.82) and also with reducing power, using CUPRAC (0.66) were observed. The darker color of honey is indicative of higher phenol content and antioxidant capacity. The reported characteristics give an enhanced functional food property to honey and contribute to the development of the regional economy, providing an alternative to family income increase.

Interest Aware Consistency for Cooperative Editing in Heterogeneous Environments

Cooperative editing applications enable geographically distributed users to concurrently edit a shared document space over a computer network. These applications present several technical challenges related to the scalability of the system and the promptness with which relevant updates are disseminated to the concerned users. This paper presents Cooperative Semantic Locality Awareness (CoopSLA), a consistency model for cooperative editing applications that is scalable and efficient with regards to user needs. In CoopSLA, updates to different parts of the document have different priorities, depending on the relative interest of the user in the region in which the update is performed; updates that are considered relevant are sent to the user promptly, while less important updates are postponed. As a result, the system makes a more intelligent usage of the network resources, since (1) it saves bandwidth by merging postponed updates and (2) it issues fewer accesses to the network resources as a result of both update merging and message aggregation. We have implemented a collaborative version of the open source Tex editor TexMaker using the CoopSLA approach. We present evaluation results that support our claim that CoopSLA is very effective regarding network usage while fulfilling user needs (e.g. ensuring that relevant updates are disseminated in time).

Efeito de diferentes arranjos no consorcio milho-feijao e milho-caupi no Acre, Brasil

To study the arrangement of mixtures of maize (Zea mays L.) with beans (Phaseolus vulgaris L.) or cowpea (Vigna unguiculata (L.) Walp), mixed cropping experiments were planted in 1995 and 1996, in Rio Branco, Acre. Four different arrangements (one, three, five, seven rows of beans or cowpeatone row maize) were tested in a randomized block design with four replications. The productivity of the beans and the cowpea in the 1:1 arrangement proved to be significantly inferior to the others, showing that the legumes were effected by the competition with the maize. The productivity of the maize decreased linearly in accordance with the arrangement owing to lower population densities. The most promising mixture, demonstrated by equivalent productivity, was composed of a row of maize to three rows of legumes.

Phytotherapy in pediatrics: the production of knowledge and practices in Primary Care

OBJECTIVE To demonstrate the use of phytotherapy as a therapy adopted in the context of Primary Care to Childhood. METHOD Observational and analytical field research, with quantitative-qualitative approach. A semi-structured survey was used on socio-demographic and ethnopharmacological variables, audio interview and daily observation. RESULTS The production of knowledge about phytotherapy constitutes a family heritage, but incorporated data resulting from the daily experiences shared by the community. The main factors were: easy access to this resource, high costs of conventional treatment, difficulty in accessing medical services and belief in the power of plants. The attributed meanings were: prevention and treatment of injuries, rescue of memory and of experiences, factor integrative with nature and aggregative among members of the community. FINAL CONSIDERATIONS Rescuing this tradition brings a new meaning to health care.