RESUMEN
The work reported here is an extension of our previous findings in which supercritical composite particles (SCP) of alpha lipoic acid (ALA) masked with hydrogenated colza oil (HCO) named as ALA/HCO/SCP were obtained by the modified particles from gas-saturated solutions (PGSS) process in supercritical carbon dioxide in order to obscure the unpleasant taste and odor of ALA. The masking effect on ALA/HCO/SCP was compared with the widely used mechano-chemically masked formulation of ALA and HCO named as MC-50F. In the present study, ALA/HCO/SCP particles were found to have a significant improvement in regard to bitterness, numbness, and smell compared to ALA bulk powders suggesting they were well coated. The pharmacokinetic parameters for ALA/HCO/SCP and ALA bulk powder gave similar values but were significantly different from those of MC-50F. The amount of ALA absorbed into the body, in the administered ALA/HCO/SCP, was comparable to that absorbed by ALA bulk powder, whereas about half portion of ALA of the MC-50F was not absorbed, because the ALA/HCO/SCP particles were small enough and the particles of MC-50F were relatively large and had smaller specific surface area. Therefore, this study suggested a newly masked candidate may offer functional particles with maintained efficacy.
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Dióxido de Carbono/química , Aceites de Plantas/química , Ácido Tióctico/administración & dosificación , Animales , Masculino , Tamaño de la Partícula , Ratas , Ratas Sprague-Dawley , Propiedades de Superficie , Ácido Tióctico/farmacocinéticaRESUMEN
BACKGROUND: Lactobacilli show anti-inflammatory effects in the human intestine, and their genomic DNA was identified as one of the anti-inflammatory components. Increased levels of the natural protease inhibitor elafin in the intestine plays an important role in protection against intestinal inflammation. However, there have been no previous reports regarding whether lactobacilli increase elafin levels. OBJECTIVE: This study was performed to investigate whether Lactobacillus plantarum induces elafin secretion from the human epithelial colorectal adenocarcinoma cell line, Caco-2. Moreover, we examined the roles of bacterial genomic DNA and toll-like receptor 9 (TLR9), a specific receptor of bacterial DNA, in this effect. METHODS: Elafin secretion from Caco-2 cells by live and heat-killed L. plantarum was measured. The analysis was also performed using DNase-treated L. plantarum and genomic DNA extracted from L. plantarum. We examined the role of TLR9 in elafin secretion by L. plantarum and its genomic DNA by suppressing TLR9 expression using RNAi in Caco-2 cells. RESULTS: Heat-killed L. plantarum time- and dose-dependently increased elafin secretion, whereas live L. plantarum had no such effect. The elafin secretion by heat-killed L. plantarum was partially abolished by DNase treatment of the bacterium. In addition, L. plantarum genomic DNA also increased elafin secretion. Furthermore, suppression of TLR9 expression partially or completely abolished elafin secretion by heat-killed L. plantarum and its genomic DNA. CONCLUSION: Our results indicated that heat-killed L. plantarum induced genomic DNA-dependent and TLR9-mediated elafin secretion. The anti-inflammatory effects of lactobacilli may be mediated by increases in the levels of elafin in the intestine.
Asunto(s)
ADN Bacteriano , Elafina/biosíntesis , Interacciones Huésped-Patógeno/genética , Lactobacillus plantarum/fisiología , Receptor Toll-Like 9/metabolismo , Células CACO-2 , Infecciones por Bacterias Grampositivas/genética , Infecciones por Bacterias Grampositivas/metabolismo , Infecciones por Bacterias Grampositivas/microbiología , Calor , HumanosRESUMEN
BACKGROUND & OBJECTIVES: In sterile insect technology (SIT), mating competitiveness is a pre-condition for the reduction of target pest populations and a crucial parameter for judging efficacy. Still, current SIT trials are being hindered by decreased effectiveness due to reduced sexual performance of released males. Here, we explored the possible role of a herbal aphrodisiac in boosting the mating activity of Aedes aegypti. METHODS: Males were fed one of two diets in this study: experimental extract of Eurycoma longifolia (MSAs) and sugar only (MSOs). Differences in life span, courtship latency, copulation activity and mating success were examined between the two groups. RESULTS: No deaths occurred among MSA and MSO males. Life span of MSOs was similar to that of MSAs. The courtship latency of MSAs was shorter than that of MSOs (P<0.01). MSAs had greater copulation success than MSOs (P<0.001). In all female treatments, MSAs mated more than MSOs, but the differences in rate were significant only in the highest female density (P<0.05). In MSAs, mating success varied significantly with female density (P<0.01), with the 20-female group (P<0.01) having the lowest rate. Single MSA had better mating success at the two lowest female densities. In MSOs, there were no significant differences in mating success rate between the different female densities. INTERPRETATION & CONCLUSIONS: Our results suggested that the herbal aphrodisiac, E. longifolia, stimulated the sexual activity of Ae. aegypti and may be useful for improving the mating competitiveness of sterile males, thus improving SIT programmes.
Asunto(s)
Afrodisíacos/farmacología , Eurycoma , Mosquitos Vectores , Control Biológico de Vectores/métodos , Aedes/efectos de los fármacos , Aedes/fisiología , Animales , Copulación/efectos de los fármacos , Insectos , Insecticidas/farmacología , Inseminación/efectos de los fármacos , Control de Mosquitos , Mosquitos Vectores/efectos de los fármacos , Mosquitos Vectores/fisiologíaRESUMEN
Culture supernatants of Bordetella pertussis are a brilliant yellow; however, the structure and biological role of the responsible pigment have not been investigated. In this study, a brilliant yellow-colored fraction was extracted from culture supernatants of B. pertussis and analyzed by HPLC. UV-visible spectral analysis and mass spectrometry identified the brilliant yellow pigment as riboflavin. Riboflavin production was high in lag and early log phases and riboflavin was found to enhance growth of B. pertussis in low-density cultures. Riboflavin production is not regulated by the BvgAS system. In addition, it was found that other Bordetella species, such as B. parapertussis, B. holmesii and B. bronchiseptica, also release riboflavin into their culture supernatants. This is the first report that B. pertussis secrets riboflavin to the extracellular space and that riboflavin may promote its growth. The mechanism may be associated with pathogenesis of B. pertussis.
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Bordetella pertussis/metabolismo , Pigmentos Biológicos/metabolismo , Bordetella pertussis/química , Bordetella pertussis/crecimiento & desarrollo , Cromatografía Líquida de Alta Presión , Espectrometría de Masas , Pigmentos Biológicos/química , Riboflavina/química , Riboflavina/metabolismoRESUMEN
BACKGROUND: MF59, which is an adjuvant belonging to C30 member of the terpene family, is a T helper type-2 (Th2)-biased immune enhancer. Our previous studies showed that pyriproxyfen, a member of the terpene family with fewer carbon atoms (C20) than MF59, enhanced active T helper type-1 (Th1)-biased immune responses. OBJECTIVE: This study was performed to investigate the enhancement of antigen-specific immune responses by myrcene, a member of the terpene family with fewer carbon atoms (C10) than pyriproxyfen. METHOD: Ovalbumin (OVA) was used as an antigen to determine the effects of myrcene on the immune response. The IgG subtypes and cytokines induced by immunization of OVA with or without myrcene were monitored. Thereafter, we determined the effects of myrcene in the immune response against Ag85B, which is a dominant protective antigen for tuberculosis. RESULTS: The results showed that 0.8 mg/dose of myrcene enhanced antigen-specific total IgG immune response to OVA. Direct mixing of the antigen with myrcene was required for the enhancement of antibody production. Myrcene increased OVA-specific IgG2a titer, suggesting induction of Th1-immune response. The level of Th1 cytokines, IFN-γ was increased at 8 weeks after immunization, although IL-13 was also increased at the same time point. However, finally myrcene was found to increase Ag85B-specific total IgG titers at 5 weeks and specific IgG2a titer was increased at both 5 and 8 weeks. The results suggested that myrcene could enhance Th1 immune response. CONCLUSIONS: Myrcene enhanced specific immune responses against OVA and Ag85B. This study suggested the tendency of the enhancement of Th1 immune response by myrcene.
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Adyuvantes Inmunológicos/farmacología , Alquenos/farmacología , Formación de Anticuerpos/efectos de los fármacos , Monoterpenos/farmacología , Monoterpenos Acíclicos , Aciltransferasas/inmunología , Animales , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Ensayo de Inmunoadsorción Enzimática , Femenino , Inmunoglobulina G , Ratones , Ratones Endogámicos BALB C , Ovalbúmina/inmunología , Células TH1/inmunologíaRESUMEN
BACKGROUND: Lactobacillus species are used as bacterial vectors to deliver functional peptides to the intestine because they are delivered live to the intestine, colonize the mucosal surface, and continue to produce the desired protein. Previously, we generated a recombinant Lactobacillus casei secreting the cholera toxin B subunit (CTB), which can translocate into intestinal epithelial cells (IECs) through GM1 ganglioside. Recombinant fusion proteins of CTB with functional peptides have been used as carriers for the delivery of these peptides to IECs because of the high cell permeation capacity of recombinant CTB (rCTB). However, there have been no reports of rCTB fused with peptides expressed or secreted by Lactobacillus species. In this study, we constructed L. casei secreting a recombinant fusion protein of CTB with YVAD (rCTB-YVAD). YVAD is a tetrapeptide (tyrosine-valine-alanine-aspartic acid) that specifically inhibits caspase-1, which catalyzes the production of interleukin (IL)-1ß, an inflammatory cytokine, from its inactive precursor. Here, we examined whether rCTB-YVAD secreted by L. casei binds to GM1 ganglioside and inhibits caspase-1 activation in Caco-2 cells used as a model of IECs. RESULTS: We constructed the rCTB-YVAD secretion vector pSCTB-YVAD by modifying the rCTB secretion vector pSCTB. L. casei secreting rCTB-YVAD was generated by transformation with pSCTB-YVAD. Both the culture supernatant of pSCTB-YVAD-transformed L. casei and purified rCTB-YVAD bound to GM1 ganglioside, as did the culture supernatant of pSCTB-transformed L. casei and purified rCTB. Interestingly, although both purified rCTB-YVAD and rCTB translocated into Caco-2 cells, regardless of lipopolysaccharide (LPS), only purified rCTB-YVAD but not rCTB inhibited LPS-induced caspase-1 activation and subsequent IL-1ß secretion in Caco-2 cells, without affecting cell viability. CONCLUSIONS: The rCTB protein fused to a functional peptide secreted by L. casei can bind to GM1 ganglioside, like rCTB, and recombinant YVAD secreted by L. casei may exert anti-inflammatory effects in the intestine. Therefore, rCTB secreted by L. casei has potential utility as a vector for the delivery of YVAD to IECs.
Asunto(s)
Caspasa 1/metabolismo , Toxina del Cólera/metabolismo , Interleucina-1beta/metabolismo , Lacticaseibacillus casei/metabolismo , Oligopéptidos/metabolismo , Secuencia de Aminoácidos , Células CACO-2 , Supervivencia Celular/efectos de los fármacos , Toxina del Cólera/genética , Toxina del Cólera/farmacología , Activación Enzimática/efectos de los fármacos , Humanos , Lipopolisacáridos/toxicidad , Oligopéptidos/química , Oligopéptidos/genética , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/farmacologíaRESUMEN
There have been few reports regarding the long-term trends in the genotypes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates. Therefore, this study was performed to investigate the longitudinal trends in the genotypes of MRSA bloodstream isolates obtained from hospitalized patients during a 12-year study period from 2010 to 2021 at a tertiary care university hospital. Over the 12-year period from 2010 to 2021, we conducted a genetic investigation focusing on 245 MRSA strains isolated from the blood of hospitalized patients. The genotypes of the MRSA bloodstream isolates were determined by Staphylococcal Cassette Chromosome mec (SCCmec) typing, accessory gene regulator (agr) typing, PCR-based ORF typing (POT), and multilocus sequence typing (MLST). Strains with the same POT type detected in two or more isolates were designated as epidemic clones, while strains without a common POT type were classified as sporadic clones. Until 2015, isolates with SCCmec II/agr II were prevalent, but isolates with SCCmec IV/agr III increased from 2016. A total of 128 strains (52%) were identified as epidemic clones, while 117 strains (48%) were classified as sporadic clones. The detection rate of sporadic clones increased significantly since 2016 (p < 0.05). The epidemic clones were classified into three clusters, with MRSA of clonal complex (CC) 1 being prominent after 2016. This study showed that the genotypes of MRSA bloodstream isolates underwent a shift from SCCmec II/agr II type to SCCmec IV/agr III type, with a notable increase in MRSA of CC1, after 2016. There was a significant increase in the proportion of sporadic strains among the isolates, suggesting the diversification of genotypes.
RESUMEN
In this study, we isolated and characterized an insect nidovirus from the mosquito Culex tritaeniorhynchus Giles (Diptera: Culicidae) in Vietnam, as an additional member of the new family Mesoniviridae in the order Nidovirales. The virus, designated "Dak Nong virus (DKNV)," shared many characteristics with Cavally virus and Nam Dinh virus, which have also been discovered recently in mosquitoes, and these viruses should be considered members of a single virus species, Alphamesonivirus 1. DKNV grew in cultured mosquito cells but could not replicate in the cultured vertebrate cells tested. N-terminal sequencing of the DKNV structural proteins revealed two posttranslational cleavage sites in the spike glycoprotein precursor. DKNV is assumed to be a new member of the species Alphamesonivirus 1, and the current study provides further understanding of viruses belonging to the new family Mesoniviridae.
Asunto(s)
Culex/virología , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificación , Nidovirales/clasificación , Nidovirales/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Chlorocebus aethiops , Cricetinae , Femenino , Virus de Insectos/genética , Virus de Insectos/crecimiento & desarrollo , Datos de Secuencia Molecular , Nidovirales/genética , Nidovirales/crecimiento & desarrollo , Filogenia , Análisis de Secuencia de ADN , Células Vero , Vietnam , Proteínas Virales/química , Proteínas Virales/genética , Proteínas Virales/metabolismoRESUMEN
Pyriproxyfen is a juvenile hormone mimic of vital importance for insect development with little risk to humans. This study was performed to investigate whether large doses of pyriproxyfen affect the immune response in mammals. Mice were immunized thrice with ovalbumin in 5% ethanol, with or without pyriproxyfen or alum. Large doses of pyriproxyfen (9 or 15 mM) significantly enhanced specific total IgG immune response. This enhancement was no longer present 24 hr after treatment with pyriproxyfen. These results suggest that pyriproxyfen is a safe chemical. Moreover, pyriproxyfen induced higher titers of IgG2a and enhanced tumor necrosis factor-alpha and gamma-interferon responses whereas alum induced IgG1 with enhanced interleukin-4 and -10. These observations indicate that the mechanism of immune enhancement by pyriproxyfen may differ from that of alum.
Asunto(s)
Inmunidad Humoral/efectos de los fármacos , Inmunoglobulina G/inmunología , Piridinas/farmacología , Animales , Especificidad de Anticuerpos/inmunología , Citocinas/sangre , Citocinas/inmunología , Relación Dosis-Respuesta a Droga , Femenino , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/clasificación , Ratones , Ovalbúmina/inmunología , Piridinas/administración & dosificación , Piridinas/química , Factores de TiempoRESUMEN
Lactic acid bacteria (LAB) are used in various fields, including in food and medical supplies. There has been a great deal of research into vaccine development using LAB as carriers due to their "generally recognized as safe" status. Cholera is an infectious disease that causes diarrhea due to cholera toxin (CT) produced by Vibrio cholerae. The pentameric cholera toxin B (CTB) subunit has no toxicity, and is used as an antigen in cholera vaccines and as a delivery molecule in vaccines to various diseases. In this study, we generated recombinant LAB expressing and secreting CTB. Here, we first report that CTB expressed and secreted from LAB bound to GM1 ganglioside. The secreted CTB was purified, and its immunogenicity was determined by intranasal administration into mice. The results of the present study suggested that it may be useful as the basis of a new oral cholera vaccine combining LAB and CTB.
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Antígenos Bacterianos/metabolismo , Toxina del Cólera/metabolismo , Lactobacillus/metabolismo , Animales , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/inmunología , Toxina del Cólera/genética , Toxina del Cólera/inmunología , Vacunas contra el Cólera/administración & dosificación , Escherichia coli/genética , Femenino , Gangliósidos/metabolismo , Inmunoglobulina G/sangre , Ratones , Ratones Endogámicos BALB C , Plásmidos , Proteínas Recombinantes/metabolismoRESUMEN
We studied the diversity of Aedes breeding sites in various urban, suburban, and rural areas over time between February 2009 and February 2010 in the dengue endemic areas of Penang Island, Malaysia. We categorized the breeding sites and efficiency, and identified the key breeding containers. Among the 3 areas, the rural areas produced the highest container index (55), followed by suburban (42) and urban (32) areas. The numbers of key premises and containers were significantly higher (P < 0.000) in rural areas. The class 1 containers were identified as the key containers with higher productivity and efficiency, although class 2 and class 4 are the highest in numbers. Aedes aegypti immatures were found mostly in drums, water reservoirs, and polyethylene sheets, while mixed breeding was more common in buckets and empty paint cans in urban and suburban areas. Aedes albopictus was found mainly in miscellaneous containers such as drums, empty paint cans, and covers in all areas. The main potential containers indoors were drums, water reservoirs, and empty paint cans, and containers outdoors included empty paint cans, drums, and polyethylene sheets.
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Culicidae , Insectos Vectores , Animales , Dengue/transmisión , Ecosistema , Humanos , Larva , Malasia , Densidad de Población , Pupa , ReproducciónRESUMEN
Larvae of Aedes albopictus Skuse typically inhabit natural and artificial containers. Since these larval habitats are replenished by rainfall, Ae. albopictus may experience increased loss of immature stages in areas with high levels of rainfall. In this study, we investigated the effects of rainfall and container water level on population density, and oviposition activity of Ae. albopictus. In field and laboratory experiments, we found that rainfall resulted in the flushing of breeding habitats. Excess rain negatively impacted larval and pupal retention, especially in small habitats. When filled with water to overflowing, container habitats were significantly repellent to ovipositing females. Taken together, these data suggest that rainfall triggers population loss of Ae. albopictus and related species through a direct detrimental effect (flushing out) and an indirect effect (ovipositional repellency).
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Aedes/fisiología , Lluvia , Animales , Femenino , Larva , Oviposición , Dinámica Poblacional , PupaRESUMEN
It is important to obtain frequent measurements of the abundance, distribution, and seasonality of mosquito vectors to determine the risk of disease transmission. The number of cases of dengue infection has increased in recent years on Penang Island, Malaysia, with recurring epidemics. However, ongoing control attempts are being critically hampered by the lack of up-to-date information regarding the vectors. To overcome this problem, we examined the current situation and distribution of dengue vectors on the island. Residences throughout the urban, suburban, and rural areas were inspected through wet and dry seasons between February 2009 and February 2010. Two vectors were encountered in the survey, with Aedes aegypti present in especially high numbers mostly in urban areas. Similar observations were noted for Ae. albopictus in rural areas. The former species was more abundant in outdoor containers, while the latter showed almost equivalent abundance both outdoors and indoors. The dengue virus was active in both urban and rural areas, and the number of cases of infection was higher in areas where Ae. aegypti was predominant. The abundance of immature Ae. albopictus was positively correlated with rainfall (r2 = 0.461; P < 0.05), but this was not the case for Ae. aegypti. For both species, the size of immature populations tended to increase with increasing intensity of rain, but heavy rains resulted in population loss. In addition to updating data regarding the larval habitats and locations (outdoors and indoors), this study highlighted the importance of spatial vector control stratification, which has the potential to reduce costs in control programs.
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Aedes/virología , Dengue/transmisión , Ecosistema , Insectos Vectores/virología , Aedes/clasificación , Aedes/fisiología , Animales , Dengue/epidemiología , Virus del Dengue/fisiología , Vivienda , Humanos , Insectos Vectores/clasificación , Insectos Vectores/fisiología , Larva/clasificación , Larva/fisiología , Larva/virología , Malasia/epidemiología , Densidad de Población , Estaciones del Año , Especificidad de la EspecieRESUMEN
There is accumulating evidence that criminals wrap dead bodies in an attempt to conceal evidence. To anticipate the forensic implications of this phenomenon, we examined whether flies that are naturally associated with cadavers exhibit a delay in attendance or differ in species composition and abundance patterns because of the presence of wrapping material. Wrapped and exposed carcasses of dead monkeys placed in an oil plantation in Kedah, Malaysia, were visited over 50 d. On daily visits to each of the six carcasses, visiting adult flies were sampled using hand nets. Flies of 12 families were encountered. Calliphoridae (Chrysomya rufifacies Macquart and C. megacephala (F.) was the most prevalent family, followed by Sphaeroceridae. Some families tended to be more abundant in WRCs (i.e., Calliphoridae, Muscidae, and Phoridae), whereas others (i.e., Piophilidae, Sepsidae, and Psychodidae) were more prevalent in exposed carcasses. Wrapping delayed the arrival of all fly species encountered, with delays varying from 1 to 13 d depending on species. Wrapping did not affect species composition of flies, but prolong the occurrence of some species. The results of the current study emphasize the need to take into consideration the presence of a wrap when estimating postmortem interval.
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Cadáver , Dípteros , Homicidio , Animales , Arecaceae , Entomología , Ciencias Forenses , Macaca fascicularis , Malasia , Tiempo (Meteorología)RESUMEN
Discarded cigarette butts (DCB) waste occurs worldwide, pollutes landscapes, is unsightly, and results in added debris removal costs. There is, therefore, a great deal of current interest in making use of DCBs in beneficial ways. Despite evidence that DCBs are harmful to water fleas (Daphnia magna), which breed in aquatic environments as do mosquito larvae, their impact on dengue vectors is unknown. We examined whether Aedes albopictus alters its ovipositional responses, larval eclosion, and development in response to presence of DCBs in its habitats. We found oviposition activity in DCB-treated water similar to that of control water and that ovipositional activity in DCB solutions steadily increased over time as those solutions aged to 10 days. Larval eclosion was initially suppressed on day 1 in DCB solution, but increased thereafter to levels similar to control larval eclosion rates. The DCB-water solutions produced significantly higher mortality in both 1st and 2nd instars over control larvae for several days after initial exposure. Mortality rates decreased sharply 3 to 5 days postexposure as DCBs continued to decompose. We found increased survival rates during late development, but daily input of fresh DCBs prevented most young larvae from completing development. Taken together, these observations suggest that decomposing did not deter gravid Ae. albopictus females from ovipositing in treated containers and that DCB solutions had larvicidal effects on early instars. Our results are discussed in the context of DCB use to control container-breeding Ae. albopictus, a competent dengue vector in Asia and other parts of the world.
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Aedes , Control de Mosquitos/métodos , Animales , Dengue/prevención & control , Femenino , Concentración de Iones de Hidrógeno , Insectos Vectores , Larva , Oviposición , Fumar , NicotianaRESUMEN
Flowers and their spatial clustering are important parameters that mediate the foraging behavior and visitation rate of pollinating insects. Visual stimuli are crucial for triggering behavioral changes in the house fly, Musca domestica, which regularly visits plants for feeding and reproduction. The success of bait technology, which is the principal means of combatting flies, is adversely affected by reduced attractiveness and ineffective application techniques. Despite evidence that house flies have color vision capacity, respond to flowers, and exhibit color and pattern preference, the potential of artificial flowers as attractive factors has not been explored. The present study was performed to investigate whether artificial floral designs can lure and kill house flies. Starved wild house flies were presented with equal opportunities to acquire sugar meals, to which boric acid had been added as a toxin, from one flower arrangement (blue-dominated design, BDD; yellow-dominated design, YDD; or pink-dominated design, PDD), and a non-toxic white design (WDD). We also allowed house flies to forage within an enclosure containing two non-toxic floral designs (WDDs). The differences in mortality between the two environments with and without toxicant were examined. The survival rate of Musca domestica was extremely high when WDDs containing non-toxic sugar sources were the only feeding sites available. When given an option to forage in an environment containing a BDD and a WDD, house flies showed a high mortality rate (76%) compared to their counterparts maintained in the WDD environment (2%). When kept in an enclosure containing one YDD and a WDD, flies showed a mortality rate of 88%; however, no mortality occurred among flies confined to a compound with a WDD pair. When provided an even chance of foraging in an enclosure containing a mixed pair of floral arrangements (PDD and WDD) and another with two WDDs, flies showed a higher mortality rate (78%) in the first environment. However, the maximum survival rate (100%) was seen in the WDD environment. Exposure to YDD tended to result in a greater mortality rate than with the two other floral designs. Mortality gradually increased with time among flies exposed to tested artificial floral designs. The results presented here clearly indicated that artificial flower arrangements with a toxic sugar reward were strikingly attractive for house flies when their preferred color (white) was present. These observations offer novel possibilities for future development of flower mimic-based house fly control.
RESUMEN
Moisture plays a major role in the dynamics of mosquito populations, especially those breeding in container habitats. Despite this importance, the role of moisture conditions as they affect oviposition and egg development in Aedes vectors remains largely unexplored. We investigated the effect of exposing gravid female Aedes albopictus mosquitoes and their eggs to different moisture levels (MLs) for various periods on oviposition and hatching. Overall, high-moisture substrates (HMSs; 66% and 72%) provided better environments for egg laying. The timing of initial egg laying was far longer at the lowest substrate moisture level (LSML, 25% and 41.2%) than at HMSs. The numbers of eggs laid were much lower in the drier environments. At LSMLs, gravid females retained increasing numbers of mature eggs until death, and egg retention decreased gradually with increasing ML. The HMSs also provided better environments for larval eclosion. The numbers of eggs hatched were lower at the LSML than the HSML environment. No egg hatching occurred after 1 h exposure to moisture. However, egg hatching occurred by installment, with spontaneous hatching (SH) increasing gradually with increasing ML. High-moisture conditions combined with long exposure (30 h and 48 h) favored SH. These results suggest that Ae. albopictus females can respond to better moisture conditions for increased success of embryonation and larval eclosion. This information may be useful in the colonization of floodwater Aedes species.
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Aedes/fisiología , Oviposición/fisiología , Agua , Aedes/embriología , Animales , Femenino , Larva/fisiología , Óvulo/fisiologíaRESUMEN
In this study, we improved a method for rapid determination of viral RNA sequences (RDV) to overcome the limitations of previous versions. The RDV ver4.0 method can detect RNA sequences with at least 1,000 copies as starting material. A novel virus, which was isolated from field-collected Aedes aegypti larvae in the Phasi Charoen district of Thailand using C6/36 cells, was identified using the RDV ver4.0 protocol. The virus was named Phasi Charoen virus (PhaV). We used a high-throughput pyrosequencing approach to obtain more information about the genome sequence of PhaV. Analysis of a phylogenic tree based on amino acid sequences strongly suggested that PhaV belongs to the family Bunyaviridae.
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Aedes/virología , Bunyaviridae/genética , Bunyaviridae/aislamiento & purificación , ARN Viral/genética , Virología/métodos , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bunyaviridae/clasificación , Chlorocebus aethiops , ADN Complementario/química , Larva/virología , Datos de Secuencia Molecular , Técnicas de Amplificación de Ácido Nucleico/métodos , Filogenia , ARN Viral/química , Células VeroRESUMEN
Sound and its reception are crucial for reproduction, survival, and population maintenance of many animals. In insects, low-frequency vibrations facilitate sexual interactions, whereas noise disrupts the perception of signals from conspecifics and hosts. Despite evidence that mosquitoes respond to sound frequencies beyond fundamental ranges, including songs, and that males and females need to struggle to harmonize their flight tones, the behavioral impacts of music as control targets remain unexplored. In this study, we examined the effects of electronic music (Scary Monsters and Nice Sprites by Skrillex) on foraging, host attack, and sexual activities of the dengue vector Aedes aegypti. Adults were presented with two sound environments (music-off or music-on). Discrepancies in visitation, blood feeding, and copulation patterns were compared between environments with and without music. Ae. aegypti females maintained in the music-off environment initiated host visits earlier than those in the music-on environment. They visited the host significantly less often in the music-on than the music-off condition. Females exposed to music attacked hosts much later than their non-exposed peers. The occurrence of blood feeding activity was lower when music was being played. Adults exposed to music copulated far less often than their counterparts kept in an environment where there was no music. In addition to providing insight into the auditory sensitivity of Ae. aegypti to sound, our results indicated the vulnerability of its key vectorial capacity traits to electronic music. The observation that such music can delay host attack, reduce blood feeding, and disrupt mating provides new avenues for the development of music-based personal protective and control measures against Aedes-borne diseases.
Asunto(s)
Aedes/fisiología , Conducta Animal , Virus del Dengue/fisiología , Control de Mosquitos/métodos , Mosquitos Vectores/virología , Sonido , Aedes/virología , Animales , Copulación , Femenino , Masculino , Mosquitos Vectores/fisiología , ReproducciónRESUMEN
Δ9-Tetrahydrocannabinol (THC) is known to have various pharmacological effects mediated through activation of cannabinoid CB1 and CB2 receptors in rodents. In adult rats, 22- and 50-kHz ultrasonic vocalizations (USVs) serve as an effective communication system and as indicators of negative and positive states, respectively. The present study was performed to determine whether THC affects USVs in adult rats, and to determine the roles of cannabinoid receptors in these effects. THC (1, 3 mg/kg) was administered intraperitoneally to adult male Wistar rats 60 min before measurement of USVs. The CB1 antagonist, SR141716 (3, 6 mg/kg), or CB2 antagonist, AM630 (1, 10 mg/kg), was administered intraperitoneally 10 min before THC. USVs were measured during a 5-minute period without air puff stimulus or with air puff stimulus. THC did not affect 22- or 50-kHz USVs without air puff stimulus. On the other hand, THC significantly increased the number of 22-kHz USVs, but not 50-kHz USVs, after air puff stimulus. Moreover, SR141716 at 6 mg/kg, but not AM630 at either dose, inhibited the increase in number of 22-kHz USVs induced by THC after air puff stimulus. These results suggest that THC induced changes in sensitivity to aversive air puff stimuli through CB1 receptors, and as a result increased emission of 22-kHz USVs in rats.