Biomedical subjects

O Marinotti

Publications and source records attributed to O Marinotti.

28 records · Page 2Linked to original sources

PubMed1998

A lysozyme in the salivary glands of the malaria vector Anopheles darlingi.

A cDNA encoding a lysozyme expressed specifically in the salivary glands of the malaria vector mosquito, Anopheles darlingi, was isolated by differential screening an adult female salivary gland library with abdomen and salivary gland cDNAs. The primary nucleic acid sequence of the cDNA contains a deduced coding region of 429 nucleotides and 5'- and 3'-end non-transcribed regions. A signal peptide of twenty-three amino acids and a mature protein of 120 amino acids are evident in the conceptual translation product. The results of RT-PCR experiments indicated that in adult mosquitoes this gene is expressed specifically in the salivary glands. Lysozyme enzymatic activity was detected in the salivary glands and abdomens of adult mosquitoes, but the pH optimum differed for each tissue and this was interpreted to indicate the presence of more than one enzyme, each being expressed in a different tissue. The salivary gland lysozyme may be involved in protection against bacterial infection in the anterior portion of the mosquito digestive tract.

Abdomen↗

PubMed1997

The nonvitellogenic female protein of Musca domestica is an adult-specific hexamerin.

During Musca domestica vitellogenesis a protein is preferentially synthesized by the female fat body and accumulates in the haemolymph but not in the ovaries. This protein, designated nonvitellogenic female protein (NVFP), was purified and shown to be a hexamer with an M(r) = 430 kDa, and subunits of M(r) = 70 kDa. The hexamer dissociates into subunits when the pH is elevated from 7.0 to 9.0. Two cDNA clones, F0 and F2, were isolated and analysed. The 2.2 kb F2 clone has an open reading frame that encodes a conceptual translation product that has similarity to the Drosophila melanogaster LSP-2 hexamerin. Recombinant protein from the F2-cDNA is recognized by a specific anti-NVFP serum. The temporal pattern of mRNA expression of the gene represented by the F2 clone follows that determined for the synthesis of NVFP. The data support the conclusion that NVFP is an hexamerin specific to the adult stage of Musca domestica.

Amino Acid Sequence↗

PubMed1997

[Resistance to organophosphorous and carbamates insecticides in a population of Culex quinquefasciatus].

The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil) has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively) to this insect population is reported. The results show the need to develop an insecticide management program. The susceptibility to permethrin (pyretroid) suggests the possibility of using this class of insecticide should the need for replacement of the insecticide in use arise.

Animals↗

PubMed1996

Apyrase and alpha-glucosidase in the salivary glands of Aedes albopictus.

An apyrase and an alpha-glucosidase were detected in the salivary glands extracts of adult Aedes albopictus. The apyrase is a 61,000 Da secreted protein that hydrolyses ATP and ADP. This protein is synthe-sized in adults and is preferentially accumulated in the distal lateral lobes of the female salivary glands. The alpha-glucosidase is a secreted 67,000 Da protein. This enzyme is synthesized during adult life and accumulated in the proximal-lateral lobes of both males and females. The results are discussed and compared with data previously obtained with Aedes aegypti salivary glands.

Aedes↗

PubMed1994

Aedes aegypti lipophorin.

The purified lipophorin of Aedes aegypti (Diptera) is composed of two apolipoproteins: apolipophorin I (M(r)=224,000) and apolipophorin II (M(r)=73,000). The density of lipophorin is constant during the Aedes life-cycle and equal to 1.11 +/- 0.01 g/ml. The amount of lipophorin per animal, during the gonotrophic cycles, increases until 48 hr after blood-feeding and then decreases until there is a new blood intake. The density values and quantification of lipophorin during Aedes aegypti gonotrophic cycle suggest that the adaptation to a higher lipid transport demand during oogenesis in Aedes aegypti is accomplished by increasing the amount of lipophorin in the hemolymph. This response is different from that observed in Musca domestica (Diptera) that does not involve changes in hemolymph lipophorin levels.

Aedes↗

PubMed1991

Isolation and characterization of the gene expressing the major salivary gland protein of the female mosquito, Aedes aegypti.

We have undertaken a molecular analysis of the salivary glands of hematophagous insects in order to better understand their role in blood feeding and in the transmission of infectious diseases. To that end, genomic and cDNA clones of a gene designated D7, expressed abundantly in the adult female salivary glands of the vector mosquito aegypti, have been isolated and characterized. This gene encodes a mRNA shown by Northern analysis and in situ hybridization to tissue sections to be specifically transcribed in the distal-lateral and medial lobes of the glands, regions that are highly differentiated in females. The deduced gene product, a protein of approximately 37 kDa appears to be novel. Polyclonal antibodies made to a recombinant D7 product recognize a protein with the proper molecular weight in female salivary glands and saliva. These studies indicate that the D7 gene probably encodes the major secreted protein synthesized in the female salivary glands. The stage- and sex-limited expression of the D7 gene, and the secretion of its product, indicate that the product is most likely involved with the blood feeding capabilities of the female mosquito.

Aedes↗

PubMed1990

A salivary vasodilator in the blood-sucking bug, Rhodnius prolixus.

1. Salivary gland homogenates of the blood-sucking bug, Rhodnius prolixus induced transient, dose-dependent relaxation of rabbit aortic preparations pre-constricted with 200 ng ml-1 noradrenaline, 1 microgram ml-1 histamine or 20 ng ml-1 angiotensin II. Such relaxations were less marked when the aorta was constricted by 60 mM KC1. These effects were observed with as little as 0.2 microgram ml-1 of crude salivary gland protein. 2. The vasodilator effect was endothelium-independent, abolished by 50 microM hydroquinone or 50 microM methylene blue, and potentiated by 30 mu ml-1 superoxide dismutase. 3. Salivary homogenates generated a coloured compound when reacted with sulfanilic acid in the presence of N-(1-naphthyl)-ethylediamine, indicating the presence of reactive nitrogen groups, equivalent to 35 +/- 3 ng of sodium nitrite per pair of glands. 4. Molecular sieving high performance liquid chromatography of salivary gland homogenates generated a single peak of vasorelaxant activity which coincided with the presence of platelet antiaggregating and spasmolytic (guinea-pig ileum contracted with histamine) activities, as well as with reactive nitrogen groups. 5. It is concluded that a protein of molecular weight 16.500 daltons in the salivary glands of R. prolixus contains reactive nitrogen groups which assist the bug during a blood meal. It is suggested that saliva of blood sucking anthropods is a natural resource of novel pharmacological activities.

Animals↗

PubMed1988

Heterogeneous glycosylation of Musca domestica arylphorin.

Two distinct fractions of Musca domestica arylphorin were isolated by affinity chromatography on Concanavalin A-Sepharose column. The results show that in the hexameric arylphorin that do not bind to the lectin there is no Concanavalin A binding subunit and in the majority of the hexamers that bind to the lectin there is only one subunit with Concanavalin A binding site. The results indicate that the carbohydrate moiety of the arylphorin is not involved in its specific uptake by the fat bodies and integument.

Algorithms↗

PubMedDate not supplied

Comparative susceptibility of two members of the Anopheles oswaldoi complex, An. oswaldoi and An. konderi, to infection by Plasmodium vivax.

We compared the susceptibility of Anopheles oswaldoi and An. konderi to infection by Plasmodium vivax based on the proportion of mosquitoes presenting oocysts and sporozoites. Anophelines were captured in the State of Acre and Rondônia, Brazilian Amazon, and used to obtain F1 progenies. After emergence of adults, male genitalia of mosquitoes of each family were dissected in order to identify them as either An. oswaldoi or An. konderi. F1 progenies of field-captured An. oswaldoi, An. konderi and An. darlingi (used as control) were fed simultaneously on P. vivax-infected blood. Mosquitoes were dissected on day 10-12 after feeding and examined for the presence of oocysts and sporozoites. Both An. oswaldoi and An. konderi developed oocysts in the midguts, however, the percentage of oocyst-positive mosquitoes for An. oswaldoi (13.8%) was higher than for An. konderi (3.3%), and only An. oswaldoi developed salivary infection with sporozoites (6.9% of positivity). Infection rates in An. darlingi ranged from 22.5% to 30.0% for both oocysts and sporozoites. These results indicate that An. oswaldoi can transmit P. vivax and suggest that it is more susceptible than An. konderi. Although An. oswaldoi is an exophilic and zoophilic species, it may be involved in malaria transmission as possibly occurred in the State of Acre.

Animals↗

PubMedDate not supplied

Evaluation of insecticide resistance and biochemical mechanisms in a population of Culex quinquefasciatus (Diptera: Culicidae) from São Paulo, Brazil.

To establish an insecticidal resistance surveillance program, Culex quinquefasciatus mosquitoes from São Paulo, Brazil, were colonized (PIN95 strain) and analyzed for levels of resistance. The PIN95 strain showed low levels of resistance to organophosphates [malathion (3.3-fold), fenitrothion (11.2-fold)] and a carbamate [propoxur (3.0-fold)]. We also observed an increase of 7.4 and 9.9 in alpha and beta esterase activities, respectively, when compared with the reference IAL strain. An alteration in the sensitivity of acetylcholinesterase to insecticide inhibition was also found in the PIN95 mosquitoes. The resistant allele (Ace.1R), however, was found at low frequencies (0.12) and does not play an important role in the described insecticide resistance. One year later, Cx. quinquefasciatus mosquitoes were collected (PIN96 strain) at the same site and compared to the PIN95 strain. The esterase activity patterns observed for the PIN96 strain were similar to those of the PIN95 mosquitoes. However the occurrence of the Ace.1R allele was statistically higher in the PIN96 strain. The results show that esterase-based insecticide resistance was established in the PIN95 Cx. quinquefasciatus population and that an acethylcholinesterase based resistant mechanism has been selected for. A continuous monitoring of this phenomenon is fundamental for rational mosquito control and insecticide application programs.

Animals↗