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Infectivity of Metarhizium flavoviride Gams & Rozsypal (Deuteromycotina: Hyphomycetes) against the grasshopper Schistocerca pallens (Thunberg) (Orthoptera: Acrididae) in the laboratory
Xavier-Santos, Solange;Magalh?es, Bonifácio P.;Lima, Elza A. Luna-Alves;
Anais da Sociedade Entomológica do Brasil , 1999, DOI: 10.1590/S0301-80591999000200025
Abstract: o gafanhoto schistocerca pallens (thunberg) (orthoptera: acrididae) tem causado prejuízos em diversas culturas no brasil e seu controle tem sido à base de inseticidas químicos, o que, freqüentemente, resulta em efeitos indesejáveis, trazendo sérios prejuízos ambientais e econ?micos. o fungo entomopatogênico metarhizium flavoviride (gams & rozsypal), candidato potencial ao controle de acridídeos em vários países, foi isolado de s. pallens no nordeste do brasil. desde ent?o, o patógeno tem sido estudado visando ao seu desenvolvimento como bioinseticida contra rhammatocerus schistocercoides (rehn), s. pallens e stiphra robusta mello-leit?o, que s?o os principais gafanhotos-praga do brasil. em testes realizados em condi??es de laboratório, aplica??es tópicas de m. flavoviride (isolado cg 423), formulado em suspens?o oleosa com diferentes concentra??es de conídios (9.000 - 21.000 conídios/inseto), causaram elevada mortalidade (> 86%) em adultos de s. pallens. n?o houve mortalidade no grupo testemunha. dentre as doses de conídios utilizadas, n?o houve diferen?a significativa quanto ao tempo médio de sobrevivência dos insetos (6,2 a 6,9 dias). esses resultados evidenciaram que m. flavoviride apresenta alta virulência a esse hospedeiro, o que estimula a intensifica??o de pesquisas visando a sua utiliza??o para o controle biológico de s. pallens.
Chromosome study in Schistocerca (Orthoptera-Acrididae-Cyrtacanthacridinae): karyotypes and distribution patterns of constitutive heterochromatin and nucleolus organizer regions (NORs)
Souza, Maria José de;Melo, Natoniel Franklin de;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000100011
Abstract: chromosome analyses were performed in two grasshopper species of the genus schistocerca, s. pallens and s. flavofasciata. both species shared the same diploid number (2n = 23, x in males; 2n = 24, xx in females);and a conserved karyotype composed exclusively of acrocentric chromosomes, but differed in their distribution patterns of constitutive heterochromatin and nucleolus organizer regions (nors). constitutive heterochromatin was located in the pericentromeric region of all chromosomes in both species. s. flavofasciata presented an additional c-band on the distal region of the long arm of a small autosome pair (s9). nucleolus organizer regions (nors), revealed by silver nitrate staining (ag-nors), were observed on a medium autosome pair (m5) in both species. s. pallens presented an additional nor-bearing autosome (m6). the same sites were labeled after fish with an rdna probe in s. pallens cells.
Polymorphism of the grasshopper Schistocerca pallens (Thunberg) (Orthoptera: Acrididae) and its natural pathogen Metarhizium flavoviride Gams & Rozsypal (Hyphomycetes), revealed by RAPD analysis
Silveira, Eni B.;Al-Janabi, Salah M.;Magalh?es, Bonifácio P.;Carvalho, Luiz J.C.B.;Tigano, Myrian S.;
Anais da Sociedade Entomológica do Brasil , 1998, DOI: 10.1590/S0301-80591998000100012
Abstract: the genetic variability of 27 individuals from two distinct populations (northeast and central brazil) of the grasshopper schistocerca pallens (thunberg) and eight isolates of its natural pathogen, the fungus metarhizium flavoviride gams & rozsypal, was investigated using rapd analysis. for the grasshoppers, ten different 10-mer oligonucleotide primers of arbitrary sequence were selected for analysis, resulting in 79 scorable binary characters. the program rapddip applied to s. pallens revealed nucleotide diversity of 2.3 and 2.2% for the populations from rio grande do norte (northeast brazil) and federal district (central brazil), respectively. these values indicate the presence of high genetic variability within these populations. conversely, the value for nucleotide divergence (0.004) showed almost no distinction between the two populations. in the case of m. flavoviride, thirty-one 10-mer oligonucleotide primers of arbitrary sequence were selected for analysis, producing 388 scorable binary characters. a dendrogram obtained for m. flavoviride, using the program ntsys, revealed high homogeneity (similarity ≥79.5%) among the 8 isolates analyzed. the brazilian isolates, all from the same geographical area and host (s. pallens), were even more homogeneous (≥98.3%).
Impact des doses sublétales de fénitrothion sur l\'ovogenèse et la capacité de ponte du criquet pèlerin Schistocera gregaria (Orthoptera : Acrididae)
SW Ouali-N'Goran, KH Koua, MA D'Almeida, K Fouabi
Sciences & Nature , 2008,
Abstract: Le criquet pèlerin est un grand ravageur des cultures sous sa forme grégaire. Le principal facteur de sa grégarisation est son grand pouvoir de reproduction. L\'objectif de cette étude est d\'évaluer l\'impact des doses sublétales de fénitrothion sur la maturité sexuelle, la capacité de ponte et la descendance de Schistocera gregaria. Sur des imagos agés de 5 jours en cage, les doses sublétales de fénitrothion de 0,01g/l par effet de contact et 0,09 g/l par effet d\'ingestion ont été appliquées à l\'aide d\'un pulvérisateur à main une fois par jour pendant 3 jours de suite. Le suivi de la maturité sexuelle s\'est fait par une dissection des ovaires sous loupe binoculaire et une étude histologique. Les résultats révèlent que les traitements aux doses sublétales de fénitrothion n\'ont pas d\'effet remarquable sur la maturité sexuelle des criquets traités. Par contre, leurs descendants restent stériles avec des ovaires atrophiés de coloration orangée. Les coupes histologiques des ovaires révèlent que les ovocytes sont réduits (8,5±0,04 mm à 0,187±0,02 mm) et bloqués en prévitellogenèse. Ces résultats sont encourageants quant à leur utilisation dans la mise en place d\'un programme de lutte intégrée contre le criquet pèlerin. Desert locust is a great destroyer of the cultures in its gregarious form. The principal factor of gregariousation is its great capacity for reproduction. The objective of this study is to evaluate the impact of sublethal doses of fenitrothion on sexual maturity, capacity of laying and the descendance of Schistocera gregaria. Sublethal doses of fénitrothion were applied using a pulverizer to 3 times during 3 days to 5 days old imagos; 0,01g/l by contact effect and 0,09g/ l by ingestion effect. The follow-up of sexual maturity was done by a dissection of ovaries under binocular magnifying glass and the histological treatments. The results show that the treatments with sublethal doses of fénitrothion haven\'t remarquable effect on sexual maturity of the treated locusts. As for their descendants, they remain sterile; with orange\'s atrophied ovaries. The histology of ovaries shows that the ovocytes reduced (8,5 ± 0,04 at 0,187±0,02mm) and are blocked in prévitellogenis. These results are encouraging as for their use in the planning of an integrated campaign against desert locust.
Do Egg Pods in the Desert Locust Schistocerca gregaria Display as Oogenesis Limiting Factor? 1-The Effect of Egg Pod Extracts on Reproductive Performance  [PDF]
M.A. Eid,S.A.S. El-Maasarawy,G. Elsayed,A.M. EI-Gammal
Pakistan Journal of Biological Sciences , 2004,
Abstract: The egg pod of Schistocerca gregaria as other Acrididae is consisted of two essential parts, the eggs and the froth plug above the buried egg mass. Froth and egg mass extracts were obtained by single solvent extractions. Solitarious and gregarious ovipositing females were exposed to contaminated ovipositing sand cups or treated antennae with froth and egg extracts. The mean number of egg pods per female and the mean number of egg per pod were significantly reduced in all treatment by contaminated sand or antennae in both solitary and gregary females, by froth and egg extracts. The fecundity and fertility are remarkably reduced in all treated females compared with control. The ethanol solvent caused higher reduction in fertility percentages than hexane extracts in case of contaminated sand. The hatched nymphs per female were significantly diminished by treatments in all cases. Furthermore, the reproductive potential were lower than control in all treatments and the decrease ranged from 42.1 to 97.4%.
Histological Effects of Cestrum Parqui Saponins on Schistocerca gregaria and Spodoptera Littoralis
Chaieb Ikbal,Trabelsi Mounir,Ben Halima-Kamel Mounia,Ben Hamouda Mohamed Habib
Journal of Biological Sciences , 2007,
Abstract: In this research try to explore the effect of injection and forced ingestion of Cestrum CSE on two insect species: Schistocerca gregaria and Spodoptera littorais. A fat body necrosis (for Spodoptera larvae) and a digestive tract softness (for Schistcerca larvae) are observed, this let us to make an histological study of these organs. Theses studies reveals a cytotoxic effect of CSE on the fat body of Spodoptera larvae, the cells of this tissue decreases in size and becomes more colored probably by loss of their cytoplasmic cotenant. More over we have noted a cell destruction of the foregut and of the gastric caeca of Schistocerca treated with CSE forced ingestion. Our hypothesis is that saponins interact with membrane cholesterol, this causes a membrane destabilization and that provokes cell death.
Functional Characterization of the Short Neuropeptide F Receptor in the Desert Locust, Schistocerca gregaria  [PDF]
Senne Dillen, Sven Zels, Heleen Verlinden, Jornt Spit, Pieter Van Wielendaele, Jozef Vanden Broeck
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053604
Abstract: Whereas short neuropeptide F (sNPF) has already been reported to stimulate feeding behaviour in a variety of insect species, the opposite effect was observed in the desert locust. In the present study, we cloned a G protein-coupled receptor (GPCR) cDNA from the desert locust, Schistocerca gregaria. Cell-based functional analysis of this receptor indicated that it is activated by both known isoforms of Schgr-sNPF in a concentration dependent manner, with EC50 values in the nanomolar range. This Schgr-sNPF receptor constitutes the first functionally characterized peptide GPCR in locusts. The in vivo effects of the sNPF signalling pathway on the regulation of feeding in locusts were further studied by knocking down the newly identified Schgr-sNPF receptor by means of RNA interference, as well as by means of peptide injection studies. While injection of sNPF caused an inhibitory effect on food uptake in the desert locust, knocking down the corresponding peptide receptor resulted in an increase of total food uptake when compared to control animals. This is the first comprehensive study in which a clearly negative correlation is described between the sNPF signalling pathway and feeding, prompting a reconsideration of the diverse roles of sNPFs in the physiology of insects.
Transcriptome Analysis of the Desert Locust Central Nervous System: Production and Annotation of a Schistocerca gregaria EST Database  [PDF]
Liesbeth Badisco,Jurgen Huybrechts,Gert Simonet,Heleen Verlinden,Elisabeth Marchal,Roger Huybrechts,Liliane Schoofs,Arnold De Loof,Jozef Vanden Broeck
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017274
Abstract: The desert locust (Schistocerca gregaria) displays a fascinating type of phenotypic plasticity, designated as ‘phase polyphenism’. Depending on environmental conditions, one genome can be translated into two highly divergent phenotypes, termed the solitarious and gregarious (swarming) phase. Although many of the underlying molecular events remain elusive, the central nervous system (CNS) is expected to play a crucial role in the phase transition process. Locusts have also proven to be interesting model organisms in a physiological and neurobiological research context. However, molecular studies in locusts are hampered by the fact that genome/transcriptome sequence information available for this branch of insects is still limited.
Contralateral Deafferentation Does Not Affect Regeneration Processes in the Auditory System of Schistocerca gregaria (Orthoptera)
Silke Krüger and Reinhard Lakes-Harlan
Journal of Experimental Neuroscience , 2012, DOI: 10.4137/JEN.S6684
Abstract: The auditory system of locusts has high regeneration capacity following injury of the peripheral afferents. Regenerating auditory afferents can re-innervate their target areas even after changed neuronal pathways. Here, possible influences of contralateral deafferentation on regenerating afferents were investigated. Contralateral deafferentation was performed at different stages of the regeneration. Regeneration was triggered by crushing the tympanal nerve. The regenerated fibers showed aberrant fiber outgrowth, reduced density of terminations in the target area, the auditory neuropile and collateral sprouts crossing the midline. However, these results were not significantly influenced by the contralateral deafferentation. Therefore the bilateral symmetrical systems seem to be largely independent from each other.
Studies of Different Application Methods of Xenorhabdus and Photorhabdus Cells and Their Toxin in Broth Solution to Control Locust (Schistocerca gregaria)  [PDF]
A.N. Mahar,M. Munir,A.Q. Mahar
Asian Journal of Plant Sciences , 2004,
Abstract: Broth culture of Xenorhabdus nematophila and Photorhabdus luminescens have been observed lethal to the nymphs of locust Schistocerca gregaria when injected into the abdomen, applied orally, mixed with bran or applied to the foliage of food plants as compared to broth alone (control). A hyperbolic relationship was observed between different bacterial application methods of cells and their metabolites and time intervals. Bacterial cells and their metabolites caused more or less similar damage to the locust but it is supposed that the insect death was probably due to the toxic metabolites present in the bacterial cells. These bacterial cells were also recovered from the abdominal haemocoele indicating that bacterial symbionts do have a free-living existence and can enter in the haemocoele in the absence of nematode vector. If these bacterial symbionts are to be used for insect control, X. nematophila would be the most appropriate as it has never been previously reported from clinical specimens.
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