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R Romi

Publications and source records attributed to R Romi.

At least 37 records · Page 2Linked to original sources

Status of malaria vectors in Italy.

About 30 yr after malaria eradication, surveys to assess the presence and abundance of anopheline vectors were carried out in central and southern Italy and in the islands of Sardinia and Sicily from 1992 to 1994. Anopheles labranchiae Falleroni was present in scattered foci in all regions, except for Tuscany, where it breeds almost exclusively in rice fields (Grosseto Province). Most common breeding sites were rivers and streams, followed by ponds and ground pools. The highest adult density was found in Tuscany near rice fields and along the west coast of Calabria. Anophelines in Grosseto were abundant at human bait, with peaks of > 200 landings per human per night and vectorial capacity between 7.3 and 26 for Plasmodium falciparum and between 8.3 and 32.5 for Plasmodium vivax. Anopheles sacharovi Favre, a former malaria vector in Puglia and Sardinia, was not found in these regions. The other vector in southern Italy, Anopheles superpictus Grassi, was found at low densities on the western and eastern coasts of Calabria. All anopheline populations were fully susceptible to deltamethrin, malathion, and DDT but showed reduced susceptibility to permethrin and propoxur. These data are discussed in the light of a possible reintroduction of malaria into Italy.

Animals↗

Esterases A5-B5 in organophosphate-resistant Culex pipiens from Italy.

Culex pipiens mosquitos from Lignano city, Udine province, northeast Italy, were found to carry over-produced non-specific esterases A1, A2-B2 and A4-B4 or A5-B5, detected by starch gel electrophoresis, giving multiple resistance to organophosphorus insecticides. In order to differentiate between A4-B4 and A5-B5 esterases, the latter known only from Cyprus whereas the former is widespread in Italy and elsewhere, restriction fragment length polymorphism (RFLP) analysis was performed at the esterase B locus. Both B4 and B5 haplotypes were found. This is the first record of A5-B5 esterase-mediated resistance in continental Europe.

Animals↗

Identification of a North American mosquito species, Aedes atropalpus (Diptera: Culicidae), in Italy.

In late September 1996, during a routine survey for Aedes albopictus in Italy, a population of Aedes atropalpus s.s. was discovered in the Veneto Region (northern Italy). Larvae were collected in 2 tire storage areas belonging to tire recapping companies that imported loads of car and large equipment used tires from eastern Europe and North America. Aedes atropalpus is found only in North America and hence it is the origin of this species. Control measures were carried out in October, but by then any remaining Ae. atropalpus would have been diapausing in the egg stage. A follow-up survey will be conducted in the spring of 1997 to assess if Ae. atropalpus has been established in the area and the extent of the spread in Italy.

Aedes↗

[Resistance to organophosphate insecticides in Culex pipiens L. (Diptera: Culicidae) and first signal of the presence of A5-B5 esterase in Italy].

After a short review on insecticide resistance in mosquitoes, the results of a study on organophosphate (OP) resistance, carried out on 2 Culex pipiens L. field populations from North-eastern Italy, are reported. The A1 an A4-B4 or A5-B5 esterases were detected in our sample by starch gel electrophoresis. In order to differentiate between A4-B4 and A5-B5 esterases, restriction fragment length polymorphism (RFLP) analysis at the esterases B locus was performed: both A4-B4 and A5-B5 aplotipes were found in one of the studied populations. This is the first record of A5-B5 esterases in continental Europe.

Animals↗

Age-related prevalence of Plasmodium falciparum circumsporozoite antibody in an hyperendemic area of Madagascar, and its relationship with parasite prevalence.

An epidemiologic survey on malaria endemicity levels, including entomologic, parasitologic, and immunologic indicators, was carried out in a village of the Madagascar highlands (Analaroa) at the end of the 1990-1991 rainy season. The results indicate that malaria is hyperendemic and Anopheles funestus is the main vector in the area. The prevalence of parasitemia decreased with age from a maximum level of about 60% in children less than five years of age to a minimum of about 16% among those more than 29 years of age. The prevalence of Plasmodium falciparum circumsporozoite antibodies (Ab-Cs) increased with age from a minimum level of about 10% in children less than five years of age to a maximum of 71.7% among those more than 29 years of age. An inverse correlation was observed between P. falciparum prevalence and levels of Ab-Cs and parasite prevalence. The study confirmed that prevalence and Ab-Cs levels are reliable indicators of malaria endemicity in hyperendemic areas. Schoolchildren between five and 14 years of age are considered the most practical and susceptible group for this kind of epidemiologic study.

Adolescent↗

Occurrence and spread in Italy of Aedes albopictus, with implications for its introduction into other parts of Europe.

Aedes albopictus is considered second only to Ae. aegypti in its importance to man as a disease vector of dengue and dengue hemorrhagic fever. The first sighting in 1979 of the vector species in Europe came from Albania; however, it was only when Ae. albopictus was introduced into Italy in 1990, through the importation of used tires, followed by its subsequent spread, that the species was considered as a threat to public health. At the close of 1995, Ae. albopictus infestations have been reported from 10 Italian regions and 19 provinces. The risk for greater distribution of Ae. albopictus in Europe can potentially be projected, based on well-established criteria such as: where the winter monthly mean temperature is 0 degree C, where at least 50 cm of mean annual rainfall occurs, and where the mean summer temperature is approximately 20 degrees C. Those countries where climatic conditions meet such criteria and that may be vulnerable to a potential introduction of Ae. albopictus include Spain, Portugal, Greece, Turkey, France, Albania, and the former Republic of Yugoslavia. The Italian plan of action, established for the surveillance and control of Ae. albopictus, is presented in detail.

Aedes↗

History and updating on the spread of Aedes albopictus in Italy.

The present distribution in Italy of Aedes albopictus, the Asian mosquito recently introduced, is described. Until now this mosquito species has been established in 8 regions of our country: Liguria, Veneto, Lazio, Lombardia, Emilia-Romagna, Toscana, Piemonte and recently Sardegna. The established populations have been able to overcome the winter season. These populations, certainly imported from temperate areas, have reconfirmed the great adaptation of the species, reaching the high latitude of 46 degrees North of the Padova area in Northern Italy. The origin of the infestation in Veneto region was shown to be strictly related to the importation of used tires and demonstrated at least for one load of tires from USA. The internal trading of tires from Veneto is the source of infestation of the other Italian regions, with the exception of Liguria and Lazio. Since the introduction and the establishment of Ae. albopictus in Italy represent a new problem of public health, a centre for the surveillance and control of this species has been set up at the Department of Parasitology, Istituto Superiore di Sanità, Roma.

Aedes↗

The kaliotoxin family enlarged. Purification, characterization, and precursor nucleotide sequence of KTX2 from Androctonus australis venom.

Kaliotoxin (KTX) has been originally described as an inhibitor of the intermediate conductance Ca(2+)-activated K+ channel (Crest, M., Jacquet, G., Gola, M., Zerrouk, H., Benslimane, A., Rochat, H., Mansuelle, P., and Martin-Eauclaire, M.-F. (1992) J. Biol. Chem. 267, 1640-1647). However, the radioiodinated 125I-KTX-(1-37) was also able to bind to the dendrotoxin sensitive voltage-dependent K+ channel (Romi, R., Crest, M., Gola, M., Sampieri, F., Jacquet, G., Zerrouk, H., Mansuelle, P., Sorokine, O., Van Dorsselaer, A., Rochat, H., Martin-Eauclaire, M.-F., and Van Rietschoten, J. (1993) J. Biol. Chem. 268, 26302-26309). By following the ability to compete with 125I-KTX-(1-37) for binding to its receptor on rat brain synaptosomes, a new kaliotoxin-like peptide, KTX2, was isolated from Androctonus australis scorpion venom. It is a 37-amino acid residue peptide, and its sequence shares 76% identity with KTX. The differences between the two peptides concern the NH2-terminal region and the residues 31 and 34 located in the region involved in the channel recognition. These differences may explain the 5-fold decrease of the molluscan Ca(2+)-activated K+ channel blockage by KTX2 (kd = 135 nM) as well as of its binding affinity to rat brain synaptosomes (IC50 = 50 pM), compared with KTX. Specific antibodies raised against KTX-(1-37) were not able to recognize KTX2. Using degenerate primers, a 370-base pair cDNA encoding the KTX2 precursor was amplified by polymerase chain reaction from a cDNA library of A. australis venom glands. It encoded a presumed signal peptide of 22 residues followed by the sequence of the mature peptide.

Amino Acid Sequence↗

Kaliotoxin (1-37) shows structural differences with related potassium channel blockers.

The three-dimensional structure of kaliotoxin (1-37), KTX(1-37), a toxin from the scorpion Androctonus mauretanicus mauretanicus that blocks calcium-dependent potassium channels, has been determined by NMR. This toxin is homologous with other scorpion toxins such as charybdotoxin (ChTX) or iberiotoxin (IbTX) for which the structures are already known, but the presence of prolines in the expected alpha-helical region suggested that there may be some major difference in the structure of KTX that could be related to its different selectivity. Proline residues are also found in the homologous region of other scorpion toxins such as noxiustoxin or margatoxin. Our results indicate that KTX(1-37) contains the same sequence of secondary structure elements as ChTX but that the helical region is shorter and distorted due to the presence of two prolines. The distortion consists of a bending in the alpha-helix and in the presence of a 3(10) helix turn in the last three residues. Furthermore, the increased length of the extended structure preceding the helix favors a different packing of this part of the molecule with respect to the secondary structure elements. This change in folding modifies the accessibility of the conserved 27Lys which is known, from mutation studies, to be involved in channel blocking by ChTX.

Amino Acid Sequence↗

Malaria epidemiological trends in Italy.

Based on the official reports received from local health laboratories, an epidemiological analysis of malaria cases reported in Italy from 1989 to 1992 is presented. A total of 1,941 cases were reported, 1,287 among Italians and 654 among foreigners. The incidence of cases was on average 500 per year with a maximum in 1990. A slight, but constant decrease of incidence of malaria cases was recorded in this period among Italian citizens (-21.5%), while the incidence among foreigners increased (+80%). Plasmodium falciparum accounted for 74.2% of total infections, followed by P. vivax (19%). The highest number of cases was imported from Africa (86.5%), followed by Asia, South America, and Oceania. 11 cases were contracted in Europe (transfusion, airport and cryptic malaria). 26 people died from malaria during the four years, with a fatality rate of 2.3% among Italians. Other epidemiological features concerning incidence in the different categories of travellers, countries of infection, clinical and therapeutic aspects of cases, are also discussed.

Adult↗

Plasmodium falciparum circumsporozoite antibody prevalence in Madagascar: a longitudinal study in three different epidemiologic areas.

A longitudinal study on the prevalence of Plasmodium falciparum circumsporozoite antibodies (Ab-CS) was carried out in 15 villages of three epidemiologic areas of Madagascar: the highlands, east coast, and the southwest region. A total of 3,967 blood samples were collected from November 1989 to April 1991 from cohorts of resident schoolchildren. The prevalence of Ab-CS in the examined population varied greatly according to the different ecoepidemiologic areas of the country. A correlation analysis was made between Ab-CS and P. falciparum parasite prevalence in the same population. High Ab-CS prevalence rates (25-75%) and levels (optical density = 0.28-0.76) were observed in the villages of the east coast (mesoendemic stable malaria). The Ab-CS prevalence rates varied from 0 to 37% in the highlands and southwest region villages (unstable malaria). The use of Ab-CS prevalence is proposed to be a useful and reliable seroepidemiologic marker of malaria endemicity in those areas of Madagascar in which malaria transmission is high and continues for more than four months a year.

Adolescent↗

Source and spread of Aedes albopictus in the Veneto region of Italy.

Colonies of Aedes albopictus were discovered at the end of the summer of 1991 in the Veneto region of Italy. To locate the source of the infestation, a detailed investigation was carried out among companies dealing in the production of recapped tires. Because most of the tires had been imported from the USA, it was surmised that this could have been one source of the infestation. This hypothesis was confirmed in the summer of 1992 following an inspection of a load of used tires from Atlanta, Georgia, in which Ae. albopictus eggs were found. Despite control measures in 1991, many colonies of Ae. albopictus are now well established in large areas of the region. Adults are active between the months of April and October. They are very susceptible to the most common insecticides.

Aedes↗

[Residual anophelism in Italy: distribution in 4 southern regions].

About 40 years after malaria eradication from Italy, the potential vectors of this disease, Anopheles labranchiae, Anopheles superpictus and Anopheles sacharovi, are still present in some regions of the South. Since 1991 the Laboratory of Parasitology, Istituto Superiore di Sanità, in collaboration with the Local Health Authorities, carried out an investigation to assess the levels of these potential anopheline vectors in Calabria, Puglia, Sicily and Sardinia. A. labranchiae, the most important vector, was found in all the regions visited, where is probably present in scattered foci all over the territory. The most common breeding sites were represented by rivers and streams, followed by ponds and ground pools. The larval densities varied greatly from 0.01 to 33 larvae/dip; likewise the adult densities, recorded in animal shelters, varied from < 10 to > 1000 female/shelter. The higher adult densities were recorded in Calabria, along the West coast. The other important vector in Southern Italy, A. superpictus, was found both in the West and East coasts of the same region, showing low larval and adult densities. Anopheles sacharovi, that was an important malaria vector in Puglia and Sardinia, was not found. Four populations of A. labranchiae were tested to determine the susceptibility to some insecticides. All of these populations were fully susceptible to deltamethrin, malathion and DDT, while showed a reduced susceptibility to permethrin and propoxur.

Animals↗

Synthesis and characterization of kaliotoxin. Is the 26-32 sequence essential for potassium channel recognition?

Kaliotoxin (KTX), a scorpion toxin characterized as a 37-residue inhibitor of the neuronal high conductance Ca(2+)-activated K+ channels (KCa channels), has been chemically synthetized. Differences were observed between natural toxin and the two peptides, KTX(1-37) and KTX(1-37)-amide. Re-examination of the KTX sequence showed that an extra lysine residue was present at the C-terminal end. The 38-residue synthetic peptide was found identical with natural toxin. All three peptides had comparable activities, with LD50 values of 6-9 pmol/mouse after intracerebroventricular injection, and Kd = 2-8 nM for blockage of the whole cell and unitary molluscan KCa currents. Pairing of the disulfide bonds in synthetic KTX corresponded to that in charybdotoxin and iberiotoxin. A competition assay between 125I-KTX(1-37) and different toxins (KTX, dendrotoxin, charybdotoxin, MCD peptide, and iberiotoxin) for binding to rat brain synaptosomal membranes suggested that KTX interacts also with voltage-gated K+ channels. Shorter peptides, KTX(25-35)-amide and KTX(26-32)-amide, expressed no KTX activity, but were able to compete in binding. They were further shown to antagonize KTX in both its toxicity and blocking activity. The (26-32) sequence of KTX, which is a highly conserved region, may contain a low affinity binding subsite essential for potassium channel recognition.

Amino Acid Sequence↗

Antibodies cross-reactive with the scorpion-toxin II from Androctonus australis Hector elicited in mice by a synthetic peptide.

With the aim of developing active protection against the noxious effects provoked in humans by scorpion stings, the possibility of eliciting toxin reactive antibodies by immunization with a short peptide was assessed in mice. The amino acid sequence of residues 50 to 59 of Androctonus australis Hector toxin II was chosen, on the basis of previous results indicating that rabbit anti-(50-59) antibodies neutralize the biological effects of the parent toxin. The peptide was prepared by solid-phase synthesis procedures and used in different forms (free, linearly polymerized, coupled to KLH, coupled to a low-molecular weight B-lymphocyte activator) in order to immunize groups of non-congenic NMRI or congenic C57BL/6 mice. The reactivities of each serum with the peptide and with the toxin were assessed in ELISA. Strong reactivities with both the peptide (mean titer over 1:52,600) and the toxin (mean titer 1:800) were observed in all mice from the group that received the KLH-coupled peptide. However, mouse immune sera failed either to recognize the toxin in a liquid-phase radioimmunoassay or to neutralize the lethal effects of the toxin. The requirements, in terms of affinity and recognition of native conformation, for anti-peptide antibodies to display neutralizing properties are discussed.

Amino Acid Sequence↗

Evaluation of structure-antigenicity relationship of peptides from human immunodeficiency virus type 1 (HIV-1) p18 protein by circular dichroism.

The antigenicity of Human Immunodeficiency Virus type 1 (HIV-1) matrix p18 protein was evaluated by analyzing the specificity of anti-p18 antibodies elicited either in HIV-1 infected humans, or in HIV-1 infected or immunized chimpanzees, against a panel of long and short overlapping synthetic peptides [from 12 to 46 amino acid (aa) residues] covering the entire sequence of p18. The relationship between peptide structure and antigenicity was further investigated by probing the secondary structures of the peptides by circular dichroism. The results obtained clearly showed the immunodominance of the N-terminal region mimicked by peptide P1 (aa 2-45), which reacted with 52 and 100% of human and chimpanzee anti-p18 sera, respectively. In contrast smaller 15 aa long peptides C1, C2, C3, C4 and P3 which cover the entire sequence of immunodominant peptide P1, showed only weak or no reactivity. In contrast to widely accepted hypotheses, circular dichroism analysis of both small and large peptides secondary structures did not show any obvious correlation between antigenicity and the ability of peptides to adopt an ordered conformation.

AIDS Vaccines↗

Mechanisms of insecticide resistance in field populations of Culex pipiens from Italy.

Results of a study on organophosphate (OP) resistance carried out on 4 Italian field populations of Culex pipiens are reported. The A1, A4-B4 and/or A5-B5 nonspecific esterases and insensitive acetylcholinesterase (AChE) were detected in our samples. A2-B2 esterases previously recorded in Italy were not observed. The A4-B4 and/or A5-B5 esterases were first found in Italy where they are at present widespread. Both nonspecific esterases and insensitive AChE are involved in OP resistance, although the high level of OP resistance observed in the Padova population could be correlated with both a high frequency of insensitive AChE and A5-B5 esterases.

Acetylcholinesterase↗

Field trials of Bacillus thuringiensis H-14 and Bacillus sphaericus (strain 2362) formulations against Anopheles arabiensis in the central highlands of Madagascar.

Malaria is highly endemic and unstable in the central Highlands plateau of Madagascar. The infection is seasonally transmitted by Anopheles funestus and An. arabiensis. The latter species is abundant especially in rice-growing areas. The field efficacies of commercial formulations of Bacillus thuringiensis H-14 and B. sphaericus (strain 2362) were assessed against An. arabiensis in 5 types of larval habitats. The granular formulation of B. thuringiensis (Vectobac GR) provided very good control in small ponds and rainwater ditches. In ricefields complete larval control was achieved with Vectobac GR and the flowable concentrate (Vectobac 12AS) at 2.5 kg/ha and 0.6 liter/ha, respectively. The granular formulation of B. sphaericus (ABG 6185) showed activity similar to that of Vectobac GR in small pools and ricefields. ABG 6185 was less effective in rainwater ditches where it gave satisfactory control at rates not lower than 6 kg/ha.

Animals↗