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PloS One 2024Ae. aegypti is the vector of important μ arboviruses, including dengue, Zika, chikungunya and yellow fever. Despite not being specifically targeted by insecticide-based...
BACKGROUND
Ae. aegypti is the vector of important μ arboviruses, including dengue, Zika, chikungunya and yellow fever. Despite not being specifically targeted by insecticide-based control programs in West Africa, resistance to insecticides in Ae. aegypti has been reported in countries within this region. In this study, we investigated the status and mechanisms of Ae. aegypti resistance in Niamey, the capital of Niger. This research aims to provide baseline data necessary for arbovirus outbreak prevention and preparedness in the country.
METHODS
Ovitraps were used to collect Ae. aegypti eggs, which were subsequently hatched in the insectary for bioassay tests. The hatched larvae were then reared to 3-5-day-old adults for WHO tube and CDC bottle bioassays, including synergist tests. The kdr mutations F1534C, V1016I, and V410L were genotyped using allele-specific PCR and TaqMan qPCR methods.
RESULTS
Ae. aegypti from Niamey exhibited moderate resistance to pyrethroids but susceptibility to organophosphates and carbamates. The kdr mutations, F1534C, V1016I and V410L were detected with the resistant tri-locus haplotype 1534C+1016L+410L associated with both permethrin and deltamethrin resistance. Whereas the homozygote tri-locus resistant genotype 1534CC+1016LL+410LL was linked only to permethrin resistance. The involvement of oxidase and esterase enzymes in resistance mechanisms was suggested by partial restoration of mosquitoes' susceptibility to pyrethroids in synergist bioassays.
CONCLUSION
This study is the first report of Ae. aegypti resistance to pyrethroid insecticides in Niamey. The resistance is underpinned by target site mutations and potentially involves metabolic enzymes. The observed resistance to pyrethroids coupled with susceptibility to other insecticides, provides data to support evidence-based decision-making for Ae. aegypti control in Niger.
Topics: Animals; Aedes; Insecticide Resistance; Pyrethrins; Niger; Insecticides; Mutation; Mosquito Vectors; Genotype; Larva; Insect Proteins
PubMed: 38809933
DOI: 10.1371/journal.pone.0304550 -
PloS One 2024A low technology emanator device for slowly releasing vapour of the volatile pyrethroid transfluthrin was recently developed in Tanzania that provides robust protection...
BACKGROUND
A low technology emanator device for slowly releasing vapour of the volatile pyrethroid transfluthrin was recently developed in Tanzania that provides robust protection against night biting Anopheles and Culex vectors of malaria and filariasis for several months. Here these same emanator devices were assessed in Dar es Salaam city, as a means of protection against outdoor-biting Aedes (Stegomia) aegypti, the most important vector of human arboviruses worldwide, in parallel with similar studies in Haiti and Brazil.
METHODS
A series of entomological experiments were conducted under field and semi-field conditions, to evaluate whether transfluthrin emanators protect against wild Ae. aegypti, and also compare the transfluthrin responsiveness of Ae. aegypti originating from wild-caught eggs to established pyrethroid-susceptible Ae. aegypti and Anopheles gambiae colonies. Preliminary measurements of transfluthrin vapour concentration in air samples collected near treated emanators were conducted by gas chromatography-mass spectrometry.
RESULTS
Two full field experiments with four different emanator designs and three different transfluthrin formulations consistently indicated negligible reduction of human landing rates by wild Ae. aegypti. Under semi-field conditions in large cages, 50 to 60% reductions of landing rates were observed, regardless of which transfluthrin dose, capture method, emanator placement position, or source of mosquitoes (mildly pyrethroid resistant wild caught Ae. aegypti or pyrethroid-susceptible colonies of Ae. aegypti and An. gambiae) was used. Air samples collected immediately downwind from an emanator treated with the highest transfluthrin dose (15g), contained 12 to 19 μg/m3 transfluthrin vapour.
CONCLUSIONS
It appears unlikely that the moderate levels of pyrethroid resistance observed in wild Ae. aegypti can explain the modest-to-undetectable levels of protection exhibited. While potential inhalation exposure could be of concern for the highest (15g) dose evaluated, 3g of transfluthrin appears sufficient to achieve the modest levels of protection that were demonstrated entomologically. While the generally low levels of protection against Aedes reported here from Tanzania, and from similar entomological studies in Haiti and Brazil, are discouraging, complementary social science studies in Haiti and Brazil suggest end-users perceive valuable levels of protection against mosquitoes. It therefore remains unclear whether transfluthrin emanators have potential for protecting against Aedes vectors of important human arboviruses.
Topics: Animals; Fluorobenzenes; Tanzania; Aedes; Cyclopropanes; Mosquito Control; Insecticides; Mosquito Vectors; Humans; Anopheles; Insect Bites and Stings; Pyrethrins
PubMed: 38809841
DOI: 10.1371/journal.pone.0299722 -
Asian Pacific Journal of Cancer... May 2024Cancer is a challenge for either the patient or the healthcare manager. Treatment protocols based on chemotherapy or radiotherapy, or both are interfering with the...
BACKGROUND
Cancer is a challenge for either the patient or the healthcare manager. Treatment protocols based on chemotherapy or radiotherapy, or both are interfering with the patient's life making him suffer rather than being alleviated. This burden pushed the scientists to search for new regimens that may help ameliorate patient as well as doctor inconvenience. Benefits of plant extracts as medical substitutes in cancer management have been proved. New nano formulated drug delivery systems may help overcoming remedy regimens barriers and obstacles. The present research topic aims to evaluate the anticancer power of two plant extracts in nano emulsion formulation on human melanoma cell line.
METHODS
Carvacrol and rosemary essential oils were obtained, and nano emulsions were formulated. NE were characterized using TEM for charge and size distribution. The A375 human melanoma cell line was cultured and propagated then IC50 of prepared NE was added. Assessment of cell cytotoxicity, effect on angiogenesis and apoptosis were tested.
RESULTS
After synthesis and characterization, both carvacrol nano emulsion (CNE) and rosemary nano emulsion (RNE) were capable of inhibiting melanoma cell line viability, angiogenesis and they enhanced the expression of caspase-3 proapoptotic marker.
CONCLUSION
Rosemary and carvacrol extract nano emulsions could be a new revolutionary agent in human melanoma therapy and these formulations can be applied locally.
Topics: Humans; Emulsions; Melanoma; Plant Extracts; Apoptosis; Cymenes; Oils, Volatile; Nanoparticles; Cell Proliferation; Tumor Cells, Cultured; Cell Survival; Cell Line, Tumor; Drug Delivery Systems
PubMed: 38809638
DOI: 10.31557/APJCP.2024.25.5.1663 -
Asian Pacific Journal of Cancer... May 2024The long-term use of trastuzumab (TRZ), a therapeutic agent for human epidermal growth factor receptor 2 (HER2)+ breast cancer subtype (HER2+ BC), induces resistance....
Characterization of Potential Target Genes of Borneol in Increasing Trastuzumab Sensitivity in HER2+ Trastuzumab-Resistant Breast Cancer: Bioinformatics and In Vitro Studies.
OBJECTIVE
The long-term use of trastuzumab (TRZ), a therapeutic agent for human epidermal growth factor receptor 2 (HER2)+ breast cancer subtype (HER2+ BC), induces resistance. Borneol (BOR) exerts anticancer effects on various types of cancer. However, its anticancer effect on HER2+ BC remains unknown. This study aimed to determine the potential target genes of BOR and its effect on overcoming the resistance of HER2+ BC to TRZ.
METHODS
The hub gene of BOR's potential target on HER2+ BC cells was determined via a bioinformatics approach. Resistant HCC1954 cells (HCC1954-TR) were obtained through repeated inducement of HCC1954 cancer cells with TRZ. The cells were then subjected to cytotoxic tests involving single compounds and their combinations. Then, the hub gene expression was determined using quantitative reverse-transcription polymerase chain reaction. The interaction between BOR and selected proteins was measured through molecular docking.
RESULTS
Hub genes IL6, TNF, ESR1, IL1B, CYP19A1, AR, NR3C1, RELA, CYP17A1, and GPT were obtained via a bioinformatics approach. HCC1954-TR cells were successfully established. The TRZ-BOR combination treatment of parental HCC1954 (400 µg/mL and 25 µM) and HCC1954-TR (800 µg/mL and 100 µM) yielded considerably better results compared with BOR or TRZ alone. The expressions of AR, GPT, and ESR1 under the TRZ-BOR combination were notably different compared with those under single exposure. The molecular docking study of CYP19A1, CYP17A1, NR3C1, and IL-1β highlighted the potential interaction between BOR and such proteins.
CONCLUSION
BOR improved the cytotoxic effects of TRZ on HCC1954 and HCC1954-TR cell lines, where it specifically targets AR, ESR1, and GPT genes. In addition, the BOR effect, which counteracted the resistance of HCC1954-TR cells to TRZ, was mediated by genes CYP19A1, CYP17A1, NR3C1, IL-1, and RELA. However, additional research is required to validate their role in BOR activity to circumvent the resistance of HER2+ BC to TRZ.
Topics: Humans; Breast Neoplasms; Trastuzumab; Drug Resistance, Neoplasm; Female; Receptor, ErbB-2; Computational Biology; Camphanes; Molecular Docking Simulation; Gene Expression Regulation, Neoplastic; Cell Proliferation; Antineoplastic Agents, Immunological; Tumor Cells, Cultured; Cell Line, Tumor
PubMed: 38809634
DOI: 10.31557/APJCP.2024.25.5.1623 -
Scientific Reports May 2024The Ae. albopictus mosquito has gained global attention due to its ability to transmit viruses, including the dengue and zika. Mosquito control is the only effective way...
Resistance to pyrethroids and the relationship between adult resistance and knockdown resistance (kdr) mutations in Aedes albopictus in dengue surveillance areas of Guizhou Province, China.
The Ae. albopictus mosquito has gained global attention due to its ability to transmit viruses, including the dengue and zika. Mosquito control is the only effective way to manage dengue fever, as no effective treatments or vaccines are available. Insecticides are highly effective in controlling mosquito densities, which reduces the chances of virus transmission. However, Ae. albopictus has developed resistance to pyrethroids in several provinces in China. Pyrethroids target the voltage-gated sodium channel gene (VGSC), and mutations in this gene may result in knockdown resistance (kdr). Correlation studies between resistance and mutations can assist viruses in managing Ae. albopictus, which has not been studied in Guizhou province. Nine field populations of Ae. albopictus at the larval stage were collected from Guizhou Province in 2022 and reared to F1 to F2 generations. Resistance bioassays were conducted against permethrin, beta-cypermethrin, and deltamethrin for both larvae and adults of Ae. albopictus. Kdr mutations were characterized by PCR and sequencing. Additionally, the correlation between the kdr allele and pyrethroid resistance was analyzed. All nine populations of Ae. albopictus larvae and adults were found to be resistant to three pyrethroid insecticides. One kdr mutant allele at codon 1016, one at 1532 and three at 1534 were identified with frequencies of 13.86% (V1016G), 0.53% (I1532T), 58.02% (F1534S), 11.69% (F1534C), 0.06% (F1534L) and 0.99% (F1534P), respectively. Both V1016G and F1534S mutation mosquitoes were found in all populations. The kdr mutation F1534S was positively correlated with three pyrethroid resistance phenotypes (OR > 1, P < 0.05), V1016G with deltamethrin and beta-cypermethrin resistance (OR > 1, P < 0.05) and F1534C only with beta-cypermethrin resistance (OR > 1, P < 0.05). Current susceptibility status of wild populations of Ae. albopictus to insecticides and a higher frequency of kdr mutations from dengue-monitored areas in Guizhou Province are reported in this paper. Outcomes of this study can serve as data support for further research and development of effective insecticidal interventions against Ae. albopictus populations in Guizhou Province.
Topics: Animals; Pyrethrins; Aedes; Insecticide Resistance; China; Dengue; Mutation; Insecticides; Mosquito Vectors; Larva; Voltage-Gated Sodium Channels; Mosquito Control; Nitriles
PubMed: 38806622
DOI: 10.1038/s41598-024-63138-0 -
Journal of Insect Science (Online) May 2024The parasitic mite Varroa destructor (Anderson and Trueman) is one of the greatest stressors of Apis mellifera (L.) honey bee colonies. When Varroa infestations reach...
The parasitic mite Varroa destructor (Anderson and Trueman) is one of the greatest stressors of Apis mellifera (L.) honey bee colonies. When Varroa infestations reach damaging levels during fall, rapid control is necessary to minimize damage to colonies. We performed a field trial in the US Southeast to determine if a combination of registered treatments (Apivar, amitraz-based; and Apiguard, thymol-based) could provide rapid and effective control of Varroa. We compared colonies that received this combination treatment against colonies that received amitraz-based positive control treatments: (i) Apivar alone; or (ii) amitraz emulsifiable concentrate ("amitraz EC"). While not registered, amitraz EC is used by beekeepers in the United States in part because it is thought to control Varroa more rapidly and effectively than registered products. Based on measurements of Varroa infestation rates of colonies after 21 days of treatment, we found that the combination treatment controlled Varroa nearly as rapidly as the amitraz EC treatment: this or other combinations could be useful for Varroa management. At the end of the 42-day trial, colonies in the amitraz EC group had higher bee populations than those in the Apivar group, which suggests that rapid control helps reduce Varroa damage. Colonies in the combination group had lower bee populations than those in the amitraz EC group, which indicates that the combination treatment needs to be optimized to avoid damage to colonies.
Topics: Animals; Toluidines; Bees; Varroidae; Thymol; Acaricides; Beekeeping
PubMed: 38805647
DOI: 10.1093/jisesa/ieae022 -
PloS One 2024A simple treated fabric device for passively emanating the volatile pyrethroid transfluthrin was recently developed in Tanzania that protected against nocturnal...
Entomological assessment of hessian fabric transfluthrin vapour emanators as a means to protect against outdoor-biting Aedes after providing them to households for routine use in Port-au-Prince, Haiti.
BACKGROUND
A simple treated fabric device for passively emanating the volatile pyrethroid transfluthrin was recently developed in Tanzania that protected against nocturnal Anopheles and Culex mosquitoes for several months. Here these transfluthrin emanators were assessed in Port-au-Prince, Haiti against outdoor-biting Aedes.
METHODS
Transfluthrin emanators were distributed to participating households in poor-to-middle class urban neighbourhoods and evaluated once every two months in terms of their effects on human landing rates of wild Aedes populations. A series of three such entomological assessment experiments were conducted, to examine the influence of changing weather conditions, various transfluthrin formulations and emanator placement on protective efficacy measurements. Laboratory experiments assessed resistance of local Aedes aegypti to transfluthrin and deltamethrin, and the irritancy and repellency of the transfluthrin-treated fabric used in the field.
RESULTS
Across all three entomological field assessments, little evidence of protection against wild Ae. aegypti was observed, regardless of weather conditions, transfluthrin formulation or emanator placement: A generalized linear mixed model fitted to the pooled data from all three assessment rounds (921 females caught over 5129 hours) estimated a relative landing rate [95% Confidence interval] of 0.87 [0.73, 1.04] for users of treated versus untreated emanators (P = 0.1241). Wild Ae. aegypti in this setting were clearly resistant to transfluthrin when compared to a fully susceptible colony.
CONCLUSIONS
Transfluthrin emanators had little if any apparent effect upon Aedes landing rates by wild Ae. aegypti in urban Haiti, and similar results have been obtained by comparable studies in Tanzania, Brazil and Peru. In stark contrast, however, parallel sociological assessments of perspectives among these same end-users in urban Haitian communities indicate strong satisfaction in terms of perceived protection against mosquitoes. It remains unclear why the results obtained from these complementary entomological and sociological assessments in Haiti differ so much, as do those from a similar set of studies in Brazil. It is encouraging, however, that similar contrasts between the entomological and epidemiological results of a recent large-scale assessment of another transfluthrin emanator product in Peru, which indicate they provide useful protection against Aedes-borne arboviral infections, despite apparently providing only modest protection against Aedes mosquito bites.
Topics: Animals; Aedes; Fluorobenzenes; Cyclopropanes; Haiti; Mosquito Control; Humans; Insecticides; Female; Pyrethrins; Mosquito Vectors; Insecticide Resistance; Insect Bites and Stings; Nitriles; Family Characteristics; Insect Repellents
PubMed: 38805442
DOI: 10.1371/journal.pone.0298919 -
PloS One 2024With the increasing frequencies of extreme weather events caused by climate change, the risk of forest damage from insect attacks grows. Storms and droughts can damage...
With the increasing frequencies of extreme weather events caused by climate change, the risk of forest damage from insect attacks grows. Storms and droughts can damage and weaken trees, reduce tree vigour and defence capacity and thus provide host trees that can be successfully attacked by damaging insects, as often observed in Norway spruce stands attacked by the Eurasian spruce bark beetle Ips typographus. Following storms, partially uprooted trees with grounded crowns suffer reduced water uptake and carbon assimilation, which may lower their vigour and decrease their ability to defend against insect attack. We conducted in situ measurements on windthrown and standing control trees to determine the concentrations of non-structural carbohydrates (NSCs), of phenolic defences and volatile monoterpene emissions. These are the main storage and defence compounds responsible for beetle´s pioneer success and host tree selection. Our results show that while sugar and phenolic concentrations of standing trees remained rather constant over a 4-month period, windthrown trees experienced a decrease of 78% and 37% of sugar and phenolic concentrations, respectively. This strong decline was especially pronounced for fructose (-83%) and glucose (-85%) and for taxifolin (-50.1%). Windthrown trees emitted 25 times greater monoterpene concentrations than standing trees, in particular alpha-pinene (23 times greater), beta-pinene (27 times greater) and 3-carene (90 times greater). We conclude that windthrown trees exhibited reduced resources of anti-herbivore and anti-pathogen defence compounds needed for the response to herbivore attack. The enhanced emission rates of volatile terpenes from windthrown trees may provide olfactory cues during bark beetle early swarming related to altered tree defences. Our results contribute to the knowledge of fallen trees vigour and their defence capacity during the first months after the wind-throw disturbance. Yet, the influence of different emission rates and profiles on bark beetle behaviour and host selection requires further investigation.
Topics: Picea; Monoterpenes; Phenols; Animals; Carbohydrates; Coleoptera; Norway; Climate Change; Wind
PubMed: 38805412
DOI: 10.1371/journal.pone.0302714 -
Plants (Basel, Switzerland) May 2024The genus is one of the largest genera in the Lamiaceae family and includes species used since ancient times in traditional medicine, as flavoring for food and as... (Review)
Review
The genus is one of the largest genera in the Lamiaceae family and includes species used since ancient times in traditional medicine, as flavoring for food and as fragrance in cosmetics. The secretory structures (represented by glandular trichomes) as well as the essential oils produced by them constitute the subject of this review. While representatives of this genus are not typically regarded as large producers of essential oils compared to other species of the Lamiaceae family, the components identified in their essential oils and their biological properties necessitate more investigation of this genus. A comprehensive analysis of the specialized literature was conducted for each of the 93 currently accepted species to identify all the results obtained by researchers regarding the secretory structures and essential oils of this genus up to the present time. Glandular trichomes, still insufficiently studied, present morphological peculiarities that differentiate this genus within the family: they are of two categories: capitate (with a wide distribution in this genus) and dendroid. The peltate trichomes, characteristic of many species of this family, are absent. The essential oils from the species of the genus have been much more widely studied than the secretory structures. They show considerable variability depending on the species and the environmental conditions.
PubMed: 38794409
DOI: 10.3390/plants13101338 -
Pharmaceuticals (Basel, Switzerland) May 2024(-)-Fenchone is a naturally occurring monoterpene found in the essential oils of Mill., L., and Molina. Pharmacological studies have reported its antinociceptive,...
(-)-Fenchone Prevents Cysteamine-Induced Duodenal Ulcers and Accelerates Healing Promoting Re-Epithelialization of Gastric Ulcers in Rats via Antioxidant and Immunomodulatory Mechanisms.
BACKGROUND
(-)-Fenchone is a naturally occurring monoterpene found in the essential oils of Mill., L., and Molina. Pharmacological studies have reported its antinociceptive, antimicrobial, anti-inflammatory, antidiarrheal, and antioxidant activities.
METHODS
The preventive antiulcer effects of (-)-Fenchone were assessed through oral pretreatment in cysteamine-induced duodenal lesion models. Gastric healing, the underlying mechanisms, and toxicity after repeated doses were evaluated using the acetic acid-induced gastric ulcer rat model with oral treatment administered for 14 days.
RESULTS
In the cysteamine-induced duodenal ulcer model, fenchone (37.5-300 mg/kg) significantly decreased the ulcer area and prevented lesion formation. In the acetic acid-induced ulcer model, fenchone (150 mg/kg) reduced ( < 0.001) ulcerative injury. These effects were associated with increased levels of reduced glutathione (GSH), superoxide dismutase (SOD), interleukin (IL)-10, and transforming growth factor-beta (TGF-β). Furthermore, treatment with (-)-Fenchone (150 mg/kg) significantly reduced ( < 0.001) malondialdehyde (MDA), myeloperoxidase (MPO), interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and nuclear transcription factor kappa B (NF-κB). A 14-day oral toxicity investigation revealed no alterations in heart, liver, spleen, or kidney weight, nor in the biochemical and hematological parameters assessed. (-)-Fenchone protected animals from body weight loss while maintaining feed and water intake.
CONCLUSION
(-)-Fenchone exhibits low toxicity, prevents duodenal ulcers, and enhances gastric healing activities. Antioxidant and immunomodulatory properties appear to be involved in its therapeutic effects.
PubMed: 38794211
DOI: 10.3390/ph17050641