Occurrence of Diaretiella rapae (Mc´Intosh, 1855 (Hymenoptera: Aphidiidae Parasitising Lipaphis erysimi (Kaltenbach, 1843 and Brevicoryne brassicae (L. 1758 (Homoptera: Aphididae in Brassica napus in Mato Grosso do Sul

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Mussury Rosilda Mara

2002-01-01

Full Text Available The occurrence of Diaretiella rapae parasitising Lipaphis erysimi and Brevicoryne brassicae in canola field (Brassica napus was evaluated through two sample methods in Dourados-MS. The methods, used weekly, were: entomologic sweep net and plants sacking. The aphids population was observed from initial to the senescence plant development. Aphids were more abundant during the flowering phase, and they were usually located in the stems of the inflorescence and development fruits. In this phase the largest parasitism level for D. rapae (89,7% occurred. The sample method with a sweep net captured significantly (t=4,484, P <= 0,01 more D. rapae while sacking method captured more parasitise aphids (t=2,199 with P <= 0,05 and active aphids (t=3,513, P <= 0,01.

A Novel Insecticidal Peptide SLP1 Produced by Streptomyces laindensis H008 against Lipaphis erysimi

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Lijian Xu

2016-08-01

Full Text Available Aphids are major insect pests for crops, causing damage by direct feeding and transmission of plant diseases. This paper was completed to discover and characterize a novel insecticidal metabolite against aphids from soil actinobacteria. An insecticidal activity assay was used to screen 180 bacterial strains from soil samples against mustard aphid, Lipaphis erysimi. The bacterial strain H008 showed the strongest activity, and it was identified by the phylogenetic analysis of the 16S rRNA gene and physiological traits as a novel species of genus Streptomyces (named S. laindensis H008. With the bioassay-guided method, the insecticidal extract from S. laindensis H008 was subjected to chromatographic separations. Finally, a novel insecticidal peptide was purified from Streptomyces laindensis H008 against L. erysimi, and it was determined to be S-E-P-A-Q-I-V-I-V-D-G-V-D-Y-W by TOF-MS and amino acid analysis.

Yield response of brassica varieties/strains in relation to mustard aphid lipaphis erysimi (kalt.)

International Nuclear Information System (INIS)

Shahzad, M.A.; Bukhari, S.A.H.; Tariq, H.

2010-01-01

Nine brassica varieties/advanced lines were tested to find out the varietal comparison against mustard aphid Lipaphis erysimi (kalt.) in relation to aphid population, average number of branches/plant, average number of grains per pod and grain yield (kg/ha) during 2004-2006. Minimum aphid population was observed on promising cultivar P-20 during both years 2004-2005 and 2005-06 which were 3.l and 23 aphid/30 cm of apical inflorescence from randomly selected five plants respectively. This promising strain also proved significantly the highest yielder and gave 1633 kg. grains/ha (2004-05) and 8 17.5 kg grains/ha (2005-06) followed by SP-36 which showed aphid population 36 and 32.5 aphid/30 cm inflorescence having yield 1373 and 780 kg grains/ha during the both periods respectively under report. The other parameters viz. Average number of branches per plant and average no. of grains/pod remained nonsignificant as far as aphid effect is concerned. (author)

Yield response of brassica varieties/strains in relation to mustard aphid lipaphis erysimi (Kalt.)

International Nuclear Information System (INIS)

Shahzad, M.A.; Bukhari, S.A.H.

2009-01-01

Nine brassica varieties/advanced lines were tested to find out the varietal comparison against mustard aphid Lipaphis erysimi (kalt.) in relation to aphid population. average number of branches/plant, average number of grains per pod and grain yield (kg/ha) during 2004-2006. Minimum aphid population was observed on promising cultivar P-20 during both years 2004-2005-06 which were 2005-06 which were 31 and 23 aphid/30 cm of apical inflorescence from randomly selected five plants respectively. This promising strain also proved significantly the highest yielder and gave 1633 kg. grains/ha (2004,05) and 817.5 kg grains/ha (2005-06) followed by SP-36 which showed aphid population 36 and 32.5 aphid/30 cm inflorescence having yield 1373 and 780 kg grains/ha during the both periods respectively under report. The other parameters viz. Average number of branches per plant and average no. of grains/pod remained non significant as far as aphid effect is concerned. (author)

Expression of Colocasia esculenta tuber agglutinin in Indian mustard provides resistance against Lipaphis erysimi and the expressed protein is non-allergenic.

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Das, Ayan; Ghosh, Prithwi; Das, Sampa

2018-06-01

Transgenic Brassica juncea plants expressing Colocasia esculenta tuber agglutinin (CEA) shows the non-allergenic nature of the expressed protein leading to enhanced mortality and reduced fecundity of mustard aphid-Lipaphis erysimi. Lipaphis erysimi (common name: mustard aphid) is the most devastating sucking insect pest of Indian mustard (Brassica juncea L.). Colocasia esculenta tuber agglutinin (CEA), a GNA (Galanthus nivalis agglutinin)-related lectin has previously been reported by the present group to be effective against a wide array of hemipteran insects in artificial diet-based bioassays. In the present study, efficacy of CEA in controlling L. erysimi has been established through the development of transgenic B. juncea expressing this novel lectin. Southern hybridization of the transgenic plants confirmed stable integration of cea gene. Expression of CEA in T 0 , T 1 and T 2 transgenic plants was confirmed through western blot analysis. Level of expression of CEA in the T 2 transgenic B. juncea ranged from 0.2 to 0.47% of the total soluble protein. In the in planta insect bioassays, the CEA expressing B. juncea lines exhibited enhanced insect mortality of 70-81.67%, whereas fecundity of L. erysimi was reduced by 49.35-62.11% compared to the control plants. Biosafety assessment of the transgenic B. juncea protein containing CEA was carried out by weight of evidence approach following the recommendations by FAO/WHO (Evaluation of the allergenicity of genetically modified foods: report of a joint FAO/WHO expert consultation, 22-25 Jan, Rome, http://www.fao.org/docrep/007/y0820e/y0820e00.HTM , 2001), Codex (Codex principles and guidelines on foods derived from biotechnology, Food and Agriculture Organization of the United Nations, Rome; Codex, Codex principles and guidelines on foods derived from biotechnology, Food and Agriculture Organization of the United Nations, Rome, 2003) and ICMR (Indian Council of Medical Research, guidelines for safety assessment of

Potential of Metarrhizium anisopliae and Beauveria bassiana isolates and Neem oil to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae); Potencial de isolados de Metarhizium anisopliae e Beauveria bassiana e do oleo de Nim no controle do pulgao Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae)

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Araujo Junior, Jose M. de; Marques, Edmilson J.; Oliveira, Jose V. de [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Dept. de Agronomia - Entomologia], e-mail: jma_junior@yahoo.com.br, e-mail: emar@depa.ufrpe.br, e-mail: vargasoliveira@uol.com.br

2009-07-15

This work aimed to determine the efficiency of the entomopathogenic fungi Metarrhizium anisopliae and Beauveria bassiana to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera:Aphididae) in kale Brassica oleracea var acephala D.C., as well as their compatibility with a neem oil formulation (Neemseto{sup R}). Ten isolates of both fungi were tested and the most pathogenic ones were B. bassiana CG001 and M. anisopliae CG30 with 90% and 4.4 days, and 64% and 3.8 days of mortality and median lethal time, respectively. Bioassays with neem at concentrations of 0.5, 1.0 and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. The neem spraying treatment at 2.0% provided 90% mortality. The use of B. bassiana isolate CG001 or M. anisopliae isolate CG30 with neem at 0.125, 0.25, and 0.5%, demonstrated that these isolates could have their spore viability or colony growth affected when exposed to neem concentrations higher than 0.25%. In absolute values, the isolates B. bassiana CG001 and M. anisopliae CG30 are the most virulent to L. erysimi, and could be utilized in the management of this pest. (author)

[Potential of Metarhizium anisopliae and Beauveria bassiana isolates and neem oil to control the Aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae)].

Science.gov (United States)

de Araujo, José M; Marques, Edmilson J; de Oliveira, José V

2009-01-01

This work aimed to determine the efficiency of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae) in kale Brassica oleracea var acephala D.C., as well as their compatibility with a neem oil formulation (Neemseto). Ten isolates of both fungi were tested and the most pathogenic ones were B. bassiana CG001 and M. anisopliae CG30 with 90% and 4.4 days, and 64% and 3.8 days of mortality and median lethal time, respectively. Bioassays with neem at concentrations of 0.5, 1.0 and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. The neem spraying treatment at 2.0% provided 90% mortality. The use of B. bassiana isolate CG001 or M. anisopliae isolate CG30 with neem at 0.125, 0.25, and 0.5%, demonstrated that these isolates could have their spore viability or colony growth affected when exposed to neem concentrations higher than 0.25%. In absolute values, the isolates B. bassiana CG001 and M. anisopliae CG30 are the most virulent to L. erysimi, and could be utilized in the management of this pest.

Potential of Metarrhizium anisopliae and Beauveria bassiana isolates and Neem oil to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae)

International Nuclear Information System (INIS)

Araujo Junior, Jose M. de; Marques, Edmilson J.; Oliveira, Jose V. de

2009-01-01

This work aimed to determine the efficiency of the entomopathogenic fungi Metarrhizium anisopliae and Beauveria bassiana to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera:Aphididae) in kale Brassica oleracea var acephala D.C., as well as their compatibility with a neem oil formulation (Neemseto R ). Ten isolates of both fungi were tested and the most pathogenic ones were B. bassiana CG001 and M. anisopliae CG30 with 90% and 4.4 days, and 64% and 3.8 days of mortality and median lethal time, respectively. Bioassays with neem at concentrations of 0.5, 1.0 and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. The neem spraying treatment at 2.0% provided 90% mortality. The use of B. bassiana isolate CG001 or M. anisopliae isolate CG30 with neem at 0.125, 0.25, and 0.5%, demonstrated that these isolates could have their spore viability or colony growth affected when exposed to neem concentrations higher than 0.25%. In absolute values, the isolates B. bassiana CG001 and M. anisopliae CG30 are the most virulent to L. erysimi, and could be utilized in the management of this pest. (author)

INFLUENCE OF TEMPERATURE ON CERTAIN BIOLOGICAL ATTRIBUTES OF A LADYBEETLE COCCINELLA SEPTEMPUNCTA TA LINNAEUS

Institute of Scientific and Technical Information of China (English)

ShefaliSrivastava; Dmkar

2003-01-01

Influence of temperature on certain biological attributes of an aphidophagous ladybeetle, Coccinella septempunctata Linnaeus, feeding on mustard aphid, Lipaphis erysimi (Kaltenbach), at five different temperatures, viz. 20, 25, 27, 30 and 35℃ was investigated. Its developmental period was shortest (11.7±0.09days) at 35℃ and longest (20.6±0.35 days) at 20℃. Developmental rate increased with increase in temperature. Hatching percent, larval survival, adult emergence and growth index were maximum at 30℃ and minimumat 20℃. Oviposition period and fecundity were highest at 30℃ and lowest at 20℃. A positive linear relationship exists between temperature and developmental rate and negative correlation between the duration of immature life stages and temperature. The proportion of developmental period allocated to each immature stage was found to be similar at each temperature regime. Thus, 30℃ was found as the most suitable for C. septempunctata amongst the five temperatures tested.

Quality of different aphids as hosts of the parasitoid Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae); Qualidade de diferentes especies de pulgoes como hospedeiros do parasitoide Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae)

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Silva, Robson J.; Bueno, Vanda H.P. [Universidade Federal de Lavras, MG (Brazil). Dept. de Entomologia]. E-mail: vhpbueno@ufla.br; Sampaio, Marcus V.[Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Ciencias Agrarias]. E-mail: mvsampaio@iciag.ufu.br

2008-03-15

Lysiphlebus testaceipes (Cresson) has a broad aphid host range; however the quality of these preys may interfere in its biological feature. This study aimed to evaluate the quality of three Macrosiphini, Brevicoryne brassicae (L.), Lipaphis erysimi (Kaltenbach) and Myzus persicae (Sulzer), and three Aphidini Schizaphis graminum (Rondani) Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover as hosts to L. testaceipes and to determine the relation possible of host preference, of size and quality of the host. The tests were carried out in climatic chamber at 25 {+-} 1 deg C, RH 70 {+-} 10% and 12h photophase. The parasitoid did not oviposite in B. brassicae and L. erysimi, while the other species were nutritionally suitable to the parasitoid. L. testaceipes showed preference for aphids from tribe Aphidini and these hosts presented better quality to the parasitoid when compared to Macrosiphini. Interactions among size, preference and quality between the Aphidini were found. L. testaceipes showed preference (parasitism rate 76.7%) for R. maidis, the bigger host (hind tibia with 0.281 mm). This host provided bigger size (hind tibia with 0.49 mm) and higher emergence rate (95.6%) to the parasitoid when compared to A. gossypii (parasitism rate of 55.7%). Also the smaller host A. gossypii (0.266 mm) provided smaller size hind tibia (0.45 mm) and higher mortality of the parasitoid (emergence rate 72.1%). However, the development time was shorter and the longevity was higher in A. gossypii (6.3 and 5.4 days, respectively) when compared to the host R. maidis (6.7 and 3.8 days, respectively), and not been related to host size. (author)

COMPARATIVE DEMOGRAPHICS OF A GENERALIST PREDATORY LADYBIRD ON FIVE APHID PREY： A LABORATORY STUDY

Institute of Scientific and Technical Information of China (English)

Omkar; AhmadPervez

2004-01-01

Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day-1, 1.2553 day-1) on A. gossypii and lowest (176.02, 0.1533 day-1, 1.1657 day-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.

Morphology versus DNA barcoding: two sides of the same coin. A case study of Ceutorhynchus erysimi and C. contractus identification.

Science.gov (United States)

Stepanović, Svetlana; Kosovac, Andrea; Krstić, Oliver; Jović, Jelena; Toševski, Ivo

2016-08-01

Genotyping of 2 well-known weevil species from the genus Ceutorhynchus (Coleoptera: Curculionidae) distributed in west Palearctic, C. erysimi and C. contractus, revealed phenotype versus genotype inconsistencies in a set of 56 specimens (25 C. erysimi and 31 C. contractus) collected from 25 locations in Serbia and Montenegro. An analysis of the mitochondrial cytochrome oxidase subunit I gene (COI), widely used as a barcoding region, and a nuclear gene, elongation factor-1α (EF-1α), revealed stable genetic divergence among these species. The average uncorrected pairwise distances for the COI and EF-1α genes were 3.8%, and 1.3%, respectively, indicating 2 genetically well-segregated species. However, the genetic data were not congruent with the phenotypic characteristics of the studied specimens. In the first place, C. erysimi genotypes were attached to specimens with phenotypic characteristics of C. contractus. Species-specific PCR-RFLP assays for the barcoding gene COI were applied for the molecular identification of 101 additional specimens of both morphospecies (33 C. erysimi and 68 C. contractus) and were found to confirm this incongruity. The discrepancy between the genetic and morphological data raises the question of the accuracy of using a barcoding approach, as it may result in misleading conclusions about the taxonomic position of the studied organism. Additionally, the typological species concept shows considerable weakness when genetic data are not supported with phenotypic characteristics as in case of asymmetric introgression, which may cause certain problems, especially in applied studies such as biological control programs in which the biological properties of the studied organisms are the main focus. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Herbivory by a Phloem-feeding insect inhibits floral volatile production.

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Pareja, Martin; Qvarfordt, Erika; Webster, Ben; Mayon, Patrick; Pickett, John; Birkett, Michael; Glinwood, Robert

2012-01-01

There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

Herbivory by a Phloem-feeding insect inhibits floral volatile production.

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Martin Pareja

Full Text Available There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

Pathogenic fungi and parasitoids of aphids present in air captures of migratory alates in the low-latitude plateau of Yunnan, China.

Science.gov (United States)

Huang, Zhi-Hong; Feng, Ming-Guang; Chen, Xue-Xin; Liu, Shu-Sheng

2008-10-01

To survey fungal pathogens and parasitoids of aphids in the low-latitude plateau of Yunnan, southwest China, 3,553 migratory alates of Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae were attracted to a yellow-plus-plant trap from air during a full-year period and individually reared on cabbage leaves for 7-14 d at 18-22 degrees C and L:D 12:12. Among the trapped alates, 19.2% were killed by 10 species of aphid-pathogenic fungi after survival of 2.3 d (range, 1-7 d). Another 2.8% were mummified by the wasps Aphidius gifuensis, Diaeretella rapae, Ephedrus plagiator, and Aphelinus mali after survival of 4.9 d (range, 1-11 d). Most of the mycosed alates (77.8%) died from Entomophthorales predominated by Pandora neoaphidis (42.7%) and Zoophthora radicans (14.5%), followed by P. nouryi, Neozygites fresenii, Conidiobiolus spp., Entomophthora planchoniana, and Z. aphidis in decreasing frequencies. A mitosporic fungus, Lecanicillium lecanii, was found frequently in L. erysimi alates trapped in rainy season. However, B. brassicae alates captured in dry season were infected or parasitized very occasionally. The predeath fecundity of the infected or parasitized alates warranted successful colonization on plants, although greatly reduced, and was well shown by the fitted probability for a given fecundity per capita and the increasing mean size of their progeny colonies. Contagious transmission of the alate-borne mycosis in most of the colonies caused high progeny mortalities within 14 d. The results highlight for the first time the diversity of aphid pathogens and the spread of both pathogens and parasitoids with host dispersal flight in the low-latitude plateau.

The Herbivore-Induced Plant Volatiles Methyl Salicylate and Menthol Positively affect Growth and Pathogenicity of Entomopathogenic Fungi

Science.gov (United States)

Lin, Yongwen; Qasim, Muhammad; Hussain, Mubasher; Akutse, Komivi Senyo; Avery, Pasco Bruce; Dash, Chandra Kanta; Wang, Liande

2017-01-01

Some herbivore-induced-plant volatiles (HIPVs) compounds are vital for the functioning of an ecosystem, by triggering multi-trophic interactions for natural enemies, plants and herbivores. However, the effect of these chemicals, which play a crucial role in regulating the multi-trophic interactions between plant-herbivore-entomopathogenic fungi, is still unknown. To fill this scientific gap, we therefore investigated how these chemicals influence the entomopathogenic fungi growth and efficacy. In this study, Lipaphis erysimi induced Arabidopsis thaliana HIPVs were collected using headspace system and detected with GC-MS, and then analyzed the effects of these HIPVs chemicals on Lecanicillium lecanii strain V3450. We found that the HIPVs menthol and methyl salicylate at 1 and 10 nmol·ml-1 improved many performance aspects of the fungus, such as germination, sporulation, appressorial formation as well as its pathogenicity and virulence. These findings are not only important for understanding the multi-trophic interactions in an ecosystem, but also would contribute for developing new and easier procedures for conidial mass production as well as improve the pathogenicity and virulence of entomopathogenic fungi in biological pest management strategies.

The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn.

Science.gov (United States)

Dar, Mudasir Irfan; Khan, Fareed Ahmad; Green, Iain D; Naikoo, Mohd Irfan

2015-10-01

The contamination of agroecosystems due to the presence of trace elements in commonly used agricultural materials is a serious issue. The most contaminated material is usually sewage sludge, and the sustainable use of this material within agriculture is a major concern. This study addresses a key issue in this respect, the fate of trace metals applied to soil in food chains. The work particularly addresses the transfer of Pb, which is an understudied element in this respect, and compares the transfer of Pb with two of the most labile metals, Cd and Zn. The transfer of these elements was determined from sludge-amended soils in a food chain consisting of Indian mustard (Brassica juncea), the mustard aphid (Lipaphis erysimi) and a predatory beetle (Coccinella septempunctata). The soil was amended with sludge at rates of 0, 5, 10 and 20 % (w/w). Results showed that Cd was readily transferred through the food chain until the predator trophic level. Zn was the most readily transferred element in the lower trophic levels, but transfer to aphids was effectively restricted by the plant regulating shoot concentration. Pb had the lowest level of transfer from soil to shoot and exhibited particular retention in the roots. Nevertheless, Pb concentrations were significantly increased by sludge amendment in aphids, and Pb was increasingly transferred to ladybirds as levels increased. The potential for Pb to cause secondary toxicity to organisms in higher trophic levels may have therefore been underestimated.

Functional alteration of a dimeric insecticidal lectin to a monomeric antifungal protein correlated to its oligomeric status.

Directory of Open Access Journals (Sweden)

Nilanjana Banerjee

Full Text Available BACKGROUND: Allium sativum leaf agglutinin (ASAL is a 25-kDa homodimeric, insecticidal, mannose binding lectin whose subunits are assembled by the C-terminal exchange process. An attempt was made to convert dimeric ASAL into a monomeric form to correlate the relevance of quaternary association of subunits and their functional specificity. Using SWISS-MODEL program a stable monomer was designed by altering five amino acid residues near the C-terminus of ASAL. METHODOLOGY/PRINCIPAL FINDINGS: By introduction of 5 site-specific mutations (-DNSNN-, a β turn was incorporated between the 11(th and 12(th β strands of subunits of ASAL, resulting in a stable monomeric mutant ASAL (mASAL. mASAL was cloned and subsequently purified from a pMAL-c2X system. CD spectroscopic analysis confirmed the conservation of secondary structure in mASAL. Mannose binding assay confirmed that molecular mannose binds efficiently to both mASAL and ASAL. In contrast to ASAL, the hemagglutination activity of purified mASAL against rabbit erythrocytes was lost. An artificial diet bioassay of Lipaphis erysimi with mASAL displayed an insignificant level of insecticidal activity compared to ASAL. Fascinatingly, mASAL exhibited strong antifungal activity against the pathogenic fungi Fusarium oxysporum, Rhizoctonia solani and Alternaria brassicicola in a disc diffusion assay. A propidium iodide uptake assay suggested that the inhibitory activity of mASAL might be associated with the alteration of the membrane permeability of the fungus. Furthermore, a ligand blot assay of the membrane subproteome of R. solani with mASAL detected a glycoprotein receptor having interaction with mASAL. CONCLUSIONS/SIGNIFICANCE: Conversion of ASAL into a stable monomer resulted in antifungal activity. From an evolutionary aspect, these data implied that variable quaternary organization of lectins might be the outcome of defense-related adaptations to diverse situations in plants. Incorporation of m

Development and survival of Aulacorthum solani, Macrosiphum euphorbiae and Uroleucon ambrosiae at six temperatures

NARCIS (Netherlands)

Conti, de B.F.; Bueno, V.H.P.; Sampaio, M.V.; Lenteren, van J.C.

2011-01-01

Temperature is one of the most important factors in determining the survival and developmental rate of aphids. The aim of this study was to evaluate the developmental time and survival of the aphid species Aulacorthum solani (Kaltenbach), Macrosiphum euphorbiae (Thomas) and Uroleucon ambrosiae

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African Journals Online (AJOL)

More- over, injections of oxytocin or oestrogenic substances have been shown to inhibit functional corpora lutea and reduce the plasma progesterone level in cattle. (Armstrong & Hansel, 1959; Kaltenbach, Niswender,. Zimmerman & Wiltbank, 1964). The rationale for using potentiating agents was to improve the response to.