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Scientific Reports Jun 2024In addition to killing, mosquito nets treated with permethrin have been claimed to repel mosquitoes, reducing their success in passing through a holed net. We have...
In addition to killing, mosquito nets treated with permethrin have been claimed to repel mosquitoes, reducing their success in passing through a holed net. We have tested this hypothesis by tracking mosquitoes in a modified World Health Organization tunnel test. In the original assay, mosquitoes are released at one end of the tunnel and have to pass through a holed piece of net to reach the bait at the other end. The mosquitoes are left in the tunnel overnight, while mortality and feeding rates are scored the following morning. Since the original test does not reveal how mosquitoes move within the tunnel, we combined the tunnel with a 3D video camera system. We tracked susceptible and permethrin-resistant Anopheles gambiae s.s. as they moved in the tunnel and interacted with an untreated or a permethrin-treated net (Olyset Net). Surprisingly, while permethrin increased the mortality and reduced blood-feeding rates, twice as many mosquitoes passed through the holes of the permethrin-treated net. The flight trajectories reveal that upon exposure to the permethrin-treated net, both mosquito colonies showed increased 'excitation', thereby augmenting their chance of getting through the holes in the net. The study underlines the complexity of behavioural modes of action of insecticides.
Topics: Animals; Permethrin; Anopheles; Mosquito Control; Video Recording; Insecticides; Insecticide-Treated Bednets; Feeding Behavior; Insecticide Resistance; Mosquito Nets
PubMed: 38866869
DOI: 10.1038/s41598-024-63968-y -
Chemical & Pharmaceutical Bulletin 2024Iridoids, which are a class of monoterpenoids, are attractive synthetic targets due to their diversely substituted cis-fused cyclopenta[c]pyran skeletons. Additionally,...
Iridoids, which are a class of monoterpenoids, are attractive synthetic targets due to their diversely substituted cis-fused cyclopenta[c]pyran skeletons. Additionally, various biological activities of iridoids raise the value of synthetic studies on this class of compounds. Here, our synthetic efforts toward 11-noriridoids; (±)-umbellatolide B (6), (±)-10-O-benzoylglobularigenin (9) and 1-O-pentenylaucubigenin (34) are described. For the efficient synthesis of target compounds, common synthetic intermediates (tricyclic enones 17 and 26) were prepared by the Pauson-Khand reaction. The cleavage of the acetal bond on the tricyclic enones and 1,2-reduction introduced the two hydroxy groups on the cyclopentane ring of the core scaffold. Furthermore, the C3-C4 olefin part was constructed by the syn-elimination of a thiocarbonate moiety to obtain 34. The developed synthetic routes for 6, 9, and 34 will be useful for the preparation of iridoid analogs that have a polyfunctionalized core skeleton.
Topics: Iridoids; Molecular Structure; Stereoisomerism
PubMed: 38866476
DOI: 10.1248/cpb.c24-00190 -
Frontiers in Chemistry 2024Essential oils (EOs) from the genus have been reported as bactericides and fungicides. However, the properties of these oils can be affected by climatic factors, as...
Essential oils (EOs) from the genus have been reported as bactericides and fungicides. However, the properties of these oils can be affected by climatic factors, as well as the collection period, which promotes changes in the chemical composition of the oil. In this context, this study aimed to evaluate the climatological influences on the chemical composition of the essential oil from the leaves of . The leaves were collected in Marajó island (Brazil) monthly for a year. The EOs were obtained by hydrodistillation and analyzed by Gas Chromatography coupled to Mass Spectrometry (GC-MS). Pearson's correlation was used to evaluate the relationship between climatic parameters, content, and chemical composition of essential oil; multivariate analysis was used to evaluate the interrelationship between samples and their chemical constituents. The constituents with the highest contents (>2.0%) in essential oils during the studied period were 1,8-cineole (28.48% ± 4.32%), α-pinene (19.58% ± 2.29%), camphor (11.98% ± 2.54%), β-pinene (9.19% ± 1.47%), limonene (6.12% ± 3.15%), α-terpineol (2.42% ± 0.25%) and borneol (2.34% ± 0.48%). β-Pinene significantly correlated ( < 0.05) with precipitation and humidity. According to the chemometric tools, two groups were formed: chemical profile I, marked by 1,8 cineole, α-pinene, β-pinene, borneol, α-terpineol, and limonene, while group II (July) presented a chemical type characterized by camphor. It is understood that the species in question can be a reliable source of biologically active components during different climatic periods in the Amazon. The chemical variability could have significant implications for the pharmaceutical industry and traditional medicine.
PubMed: 38863674
DOI: 10.3389/fchem.2024.1397634 -
Ulusal Travma Ve Acil Cerrahi Dergisi =... Jun 2024Hepatic ischemia/reperfusion (I/R) injury is a significant clinical condition that can arise during liver resections, trauma, and shock. Geraniol, an isoterpene molecule...
BACKGROUND
Hepatic ischemia/reperfusion (I/R) injury is a significant clinical condition that can arise during liver resections, trauma, and shock. Geraniol, an isoterpene molecule commonly found in nature, possesses antioxidant and hepatoprotective properties. This study investigates the impact of geraniol on hepatic damage by inducing experimental liver I/R injury in rats.
METHODS
Twenty-eight male Wistar Albino rats weighing 350-400 g were utilized for this study. The rats were divided into four groups: control group, I/R group, 50 mg/kg geraniol+I/R group, and 100 mg/kg geraniol+I/R group. Ischemia times were set at 15 minutes with reperfusion times at 20 minutes. Ischemia commenced 15 minutes after geraniol administration. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactic acid were measured, along with superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity levels in liver tissues. Liver tissues were also examined histopathologically.
RESULTS
It was observed that intraperitoneal administration of 50 mg/kg and 100 mg/kg geraniol significantly reduced AST, lactic acid, and tumor necrosis factor-alpha (TNF-α) levels. The serum ALT level decreased significantly in the 50 mg/kg group, whereas no significant decrease was found in the 100 mg/kg group. SOD and GPx enzyme activities were shown to increase significantly in the 100 mg/kg group. Although there was an increase in these enzyme levels in the 50 mg/kg group, it was not statistically significant. Similarly, CAT enzyme activity increased in both the 50 mg/kg and 100 mg/kg groups, but the increase was not significant. The Suzuki score significantly decreased in both the 50 mg/kg and 100 mg/kg groups.
CONCLUSION
The study demonstrates that geraniol reduced hepatic damage both biochemically and histopathologically and increased antioxidant defense enzymes. These findings suggest that geraniol could be used to prevent hepatic I/R injury, provided it is corroborated by large-scale and comprehensive studies.
Topics: Animals; Acyclic Monoterpenes; Reperfusion Injury; Male; Rats, Wistar; Rats; Terpenes; Liver; Disease Models, Animal; Antioxidants; Oxidative Stress; Aspartate Aminotransferases
PubMed: 38863289
DOI: 10.14744/tjtes.2024.47004 -
Parasites & Vectors Jun 2024Aedes aegypti is the primary mosquito vector for several arboviruses, such as dengue, chikungunya and Zika viruses, which cause frequent outbreaks of human disease in...
BACKGROUND
Aedes aegypti is the primary mosquito vector for several arboviruses, such as dengue, chikungunya and Zika viruses, which cause frequent outbreaks of human disease in tropical and subtropical regions. Control of these outbreaks relies on vector control, commonly in the form of insecticide sprays that target adult female mosquitoes. However, the spatial coverage and frequency of sprays needed to optimize effectiveness are unclear. In this study, we characterize the effect of ultra-low-volume (ULV) indoor spraying of pyrethroid insecticides on Ae. aegypti abundance within households. We also evaluate the effects of spray events during recent time periods or in neighboring households. Improved understanding of the duration and distance of the impact of a spray intervention on Ae. aegypti populations can inform vector control interventions, in addition to modeling efforts that contrast vector control strategies.
METHODS
This project analyzes data from two large-scale experiments that involved six cycles of indoor pyrethroid spray applications in 2 years in the Amazonian city of Iquitos, Peru. We developed spatial multi-level models to disentangle the reduction in Ae. aegypti abundance that resulted from (i) recent ULV treatment within households and (ii) ULV treatment of adjacent or nearby households. We compared fits of models across a range of candidate weighting schemes for the spray effect, based on different temporal and spatial decay functions to understand lagged ULV effects.
RESULTS
Our results suggested that the reduction of Ae. aegypti in a household was mainly due to spray events occurring within the same household, with no additional effect of sprays that occurred in neighboring households. Effectiveness of a spray intervention should be measured based on time since the most recent spray event, as we found no cumulative effect of sequential sprays. Based on our model, we estimated the spray effect is reduced by 50% approximately 28 days after the spray event.
CONCLUSIONS
The reduction of Ae. aegypti in a household was mainly determined by the number of days since the last spray intervention in that same household, highlighting the importance of spray coverage in high-risk areas with a spray frequency determined by local viral transmission dynamics.
Topics: Animals; Aedes; Insecticides; Mosquito Control; Mosquito Vectors; Pyrethrins; Spatio-Temporal Analysis; Family Characteristics; Female; Peru; Humans; Population Density; Dengue
PubMed: 38863023
DOI: 10.1186/s13071-024-06308-3 -
BMC Plant Biology Jun 2024This study examines the impact of titanium dioxide nanoparticles (TiONPs) on gene expression associated with menthol biosynthesis and selected biochemical parameters in...
Studying the impact of titanium dioxide nanoparticles on the expression of pivotal genes related to menthol biosynthesis and certain biochemical parameters in peppermint plants (Mentha Piperita L.).
BACKGROUND
This study examines the impact of titanium dioxide nanoparticles (TiONPs) on gene expression associated with menthol biosynthesis and selected biochemical parameters in peppermint plants (Mentha piperita L.). Menthol, the active ingredient in peppermint, is synthesized through various pathways involving key genes like geranyl diphosphate synthase, menthone reductase, and menthofuran synthase. Seedlings were treated with different concentrations of TiONPs (50, 100, 200, and 300 ppm) via foliar spray. After three weeks of treatment, leaf samples were gathered and kept at -70 °C for analysis.
RESULTS
According to our findings, there was a significant elevation (P ≤ 0.05) in proline content at concentrations of 200 and 300 ppm in comparison with the control. Specifically, the highest proline level was registered at 200 ppm, reaching 259.64 ± 33.33 µg/g FW. Additionally, hydrogen peroxide and malondialdehyde content exhibited a decreasing trend following nanoparticle treatments. Catalase activity was notably affected by varying TiONP concentrations, with a significant decrease observed at 200 and 300 ppm compared to the control (P ≤ 0.05). Conversely, at 100 ppm, catalase activity significantly increased (11.035 ± 1.12 units/mg of protein/min). Guaiacol peroxidase activity decreased across all nanoparticle concentrations. Furthermore, RT-qPCR analysis indicated increased expression of the studied genes at 300 ppm concentration.
CONCLUSIONS
Hence, it can be inferred that at the transcript level, this nanoparticle exhibited efficacy in influencing the biosynthetic pathway of menthol.
Topics: Titanium; Mentha piperita; Menthol; Nanoparticles; Gene Expression Regulation, Plant; Plant Proteins; Plant Leaves; Metal Nanoparticles; Genes, Plant; Hydrogen Peroxide
PubMed: 38862885
DOI: 10.1186/s12870-024-05228-9 -
Biomedicine & Pharmacotherapy =... Jul 2024Atopic dermatitis (AD) is a globally increasing chronic inflammatory skin disease with limited and potentially side-effect-prone treatment options. Monotropein is the...
Atopic dermatitis (AD) is a globally increasing chronic inflammatory skin disease with limited and potentially side-effect-prone treatment options. Monotropein is the predominant iridoid glycoside in Morinda officinalis How roots, which has previously shown promise in alleviating AD symptoms. This study aimed to systematically investigate the pharmacological effects of monotropein on AD using a 2, 4-dinitrochlorobenzene (DNCB)/Dermatophagoides farinae extract (DFE)-induced AD mice and tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated keratinocytes. Oral administration of monotropein demonstrated a significant reduction in AD phenotypes, including scaling, erythema, and increased skin thickness in AD-induced mice. Histological analysis revealed a marked decrease in immune cell infiltration in skin lesions. Additionally, monotropein effectively downregulated inflammatory markers, encompassing pro-inflammatory cytokines, T helper (Th)1 and Th2 cytokines, and pro-inflammatory chemokines in skin tissues. Notably, monotropein also led to a considerable decrease in serum immunoglobulin (Ig)E and IgG2a levels. At a mechanistic level, monotropein exerted its anti-inflammatory effects by suppressing the phosphorylation of Janus kinase / signal transducer and activator of transcription proteins in both skin tissues of AD-induced mice and TNF-α/IFN-γ-stimulated keratinocytes. In conclusion, monotropein exhibited a pronounced alleviation of AD symptoms in the experimental models used. These findings underscore the potential application of monotropein as a therapeutic agent in the context of AD, providing a scientific basis for further exploration and development.
Topics: Animals; Dermatitis, Atopic; Signal Transduction; Mice; Janus Kinases; Skin; Keratinocytes; Cytokines; Mice, Inbred BALB C; STAT Transcription Factors; Humans; Dinitrochlorobenzene; Anti-Inflammatory Agents; Female; Disease Models, Animal; Inflammation; Immunoglobulin E; Dermatophagoides farinae; Iridoids
PubMed: 38861857
DOI: 10.1016/j.biopha.2024.116911 -
BMC Complementary Medicine and Therapies Jun 2024In the past few decades, there has been a notable rise in the occurrence of several types of candidiasis. Candida albicans is the most common cause of superficial fungal...
In the past few decades, there has been a notable rise in the occurrence of several types of candidiasis. Candida albicans is the most common cause of superficial fungal infections in humans. In this study, plumieride, one of the major iridoids from Plumeria obtusa L. leaves, was isolated and investigated for its potential against Candida albicans (CA)-induced dermatitis in mice. qRT-PCR was done to assess the impact of plumieride on the expression of the major virulence genes of CA. Five groups (n = 7) of adult male BALB/c mice were categorized into: group I: non-infected mice; group II: mice infected intradermally with 10-10 CFU/mL of CA; group III: CA-infected mice treated with standard fluconazole (50 mg/kg bwt.); group IV and V: CA-infected mice treated with plumieride (25- and 50 mg/kg. bwt., respectively). All the treatments were subcutaneously injected once a day for 3 days. Skin samples were collected on the 4th day post-inoculation to perform pathological, microbial, and molecular studies. The results of the in vitro study proved that plumieride has better antifungal activity than fluconazole, manifested by a wider zone of inhibition and a lower MIC. Plumieride also downregulated the expression of CA virulence genes (ALS1, Plb1, and Hyr1). CA-infected mice showed extensive dermatitis, confirmed by strong iNOS, TNF-α, IL-1β, and NF-κB genes or immune expressions. Whereas the treatment of CA-infected mice with plumieride significantly reduced the microscopic skin lesions and modulated the expression of all measured proinflammatory cytokines and inflammatory markers in a dose-dependent manner. Plumieride interfered with the expression of C. albicans virulence factors and modulated the inflammatory response in the skin of mice infected with CA.
Topics: Animals; Mice; Mice, Inbred BALB C; Male; Candida albicans; Antifungal Agents; Iridoids; Anti-Inflammatory Agents; Candidiasis; Disease Models, Animal
PubMed: 38858704
DOI: 10.1186/s12906-024-04508-z -
BMC Plant Biology Jun 2024Light intensity is a key factor affecting the synthesis of secondary metabolites in plants. However, the response mechanisms of metabolites and genes in Gentiana...
Light intensity is a key factor affecting the synthesis of secondary metabolites in plants. However, the response mechanisms of metabolites and genes in Gentiana macrophylla under different light intensities have not been determined. In the present study, G. macrophylla seedlings were treated with LED light intensities of 15 µmol/m/s (low light, LL), 90 µmol/m/s (medium light, ML), and 200 µmol/m/s (high light, HL), and leaves were collected on the 5th day for further investigation. A total of 2162 metabolites were detected, in which, the most abundant metabolites were identified as flavonoids, carbohydrates, terpenoids and amino acids. A total of 3313 and 613 differentially expressed genes (DEGs) were identified in the LL and HL groups compared with the ML group, respectively, mainly enriched in KEGG pathways such as carotenoid biosynthesis, carbon metabolism, glycolysis/gluconeogenesis, amino acids biosynthesis, plant MAPK pathway and plant hormone signaling. Besides, the transcription factors of GmMYB5 and GmbHLH20 were determined to be significantly correlated with loganic acid biosynthesis; the expression of photosystem-related enzyme genes was altered under different light intensities, regulating the expression of enzyme genes involved in the carotenoid, chlorophyll, glycolysis and amino acids pathway, then affecting their metabolic biosynthesis. As a result, low light inhibited photosynthesis, delayed glycolysis, thus, increased certain amino acids and decreased loganic acid production, while high light got an opposite trend. Our research contributed significantly to understand the molecular mechanism of light intensity in controlling metabolic accumulation in G. macrophylla.
Topics: Gentiana; Light; Iridoids; Metabolome; Transcriptome; Gene Expression Regulation, Plant; Plant Leaves; Gene Expression Profiling
PubMed: 38858643
DOI: 10.1186/s12870-024-05217-y -
Nature Communications Jun 2024The development of Type I photosensitizers (PSs) is of great importance due to the inherent hypoxic intolerance of photodynamic therapy (PDT) in the hypoxic...
The development of Type I photosensitizers (PSs) is of great importance due to the inherent hypoxic intolerance of photodynamic therapy (PDT) in the hypoxic microenvironment. Compared to Type II PSs, Type I PSs are less reported due to the absence of a general molecular design strategy. Herein, we report that the combination of typical Type II PS and natural substrate carvacrol (CA) can significantly facilitate the Type I pathway to efficiently generate superoxide radical (O). Detailed mechanism study suggests that CA is activated into thymoquinone (TQ) by local singlet oxygen generated from the PS upon light irradiation. With TQ as an efficient electron transfer mediator, it promotes the conversion of O to O by PS via electron transfer-based Type I pathway. Notably, three classical Type II PSs are employed to demonstrate the universality of the proposed approach. The Type I PDT against S. aureus has been demonstrated under hypoxic conditions in vitro. Furthermore, this coupled photodynamic agent exhibits significant bactericidal activity with an antibacterial rate of 99.6% for the bacterial-infection female mice in the in vivo experiments. Here, we show a simple, effective, and universal method to endow traditional Type II PSs with hypoxic tolerance.
Topics: Benzoquinones; Photosensitizing Agents; Animals; Mice; Female; Photochemotherapy; Electron Transport; Staphylococcus aureus; Cymenes; Anti-Bacterial Agents; Singlet Oxygen; Superoxides; Staphylococcal Infections; Humans; Light; Mice, Inbred BALB C
PubMed: 38858372
DOI: 10.1038/s41467-024-49311-z