Oleic acid triggers burial behavior in a termite population through an odorant binding protein.

Social insects maintain hygienic conditions through their social immunity behaviors. Among these behaviors, burial behavior of termites is central for protecting healthy individuals from corpses. Many factors trigger burial behavior, and it is generally believed that chemicals released by corpses, such as oleic acid, are the most important cues for triggering burial behavior in termites. However, the contribution of the olfactory system to this behavior remains unclear. Here we report an odorant binding protein (OBP) that transports oleic acid and triggers burial behavior in Coptotermes formosanus Shiraki. We demonstrated that CforOBP7 is highly expressed in the antennae of workers. Fluorescent competition binding experiments exhibited that CforOBP7 has a strong affinity for oleic acid. Furthermore, the antennal response to oleic acid was significantly reduced, and oleic acid-triggered burial behavior was also inhibited in CforOBP7-silenced termites. We conclude that CforOBP7 governs the burial behavior of C. formosanus triggered by oleic acid.

The influence of first desaturase subfamily genes on fatty acid synthesis, desiccation tolerance and inter-caste nutrient transfer in the termite Coptotermes formosanus.

Desaturase enzymes play an essential role in the biosynthesis of unsaturated fatty acids (UFAs). In this study, we identified seven "first desaturase" subfamily genes (Cfor-desatA1, Cfor-desatA2-a, Cfor-desatA2-b, Cfor-desatB-a, Cfor-desatB-b, Cfor-desatD and Cfor-desatE) from the Formosan subterranean termite Coptotermes formosanus. These desaturases were highly expressed in the cuticle and fat body of C. formosanus. Inhibition of either the Cfor-desatA2-a or Cfor-desatA2-b gene resulted in a significant decrease in the contents of fatty acids (C16:0, C18:0, C18:1 and C18:2) in worker castes. Moreover, we observed that inhibition of most of desaturase genes identified in this study had a negative impact on the survival rate and desiccation tolerance of workers. Interestingly, when normal soldiers were reared together with dsCfor-desatA2-b-treated workers, they exhibited higher mortality, suggesting that desaturase had an impact on trophallaxis among C. formosanus castes. Our findings shed light on the novel roles of desaturase family genes in the eusocial termite C. formosanus.

Mentha spp. Essential Oils: A Potential Toxic Fumigant with Inhibition of Acetylcholinesterase Activity on Reticulitermes dabieshanensis.

In this study, we analyzed the components of Mentha spp. essential oils (EOs) and evaluated their major constituents and binary combinations against Reticulitermes dabieshanensis. We also determined the activities of esterases (ESTs), glutathione S-transferases (GSTs), and acetylcholinesterase activity (AChE) in treated insects. According to our findings, the most effective oils were those obtained from M. citrata (with the major constituent linalool constituting 45.1%), M. piperita (menthol, 49.1%), and M. spicata (carvone, 69.0%), with LC50 values of 0.176, 0.366, and 0.146 µL/L, respectively. The LC50 values were recorded for linalool (0.303 µL/L), followed by menthol (0.272 µL/L), and carvone (0.147 µL/L). The insecticidal potency increased with binary mixtures of major active constituents, with carvone strongly synergizing the toxicity of linalool and menthol against R. dabieshanensis. Compared to the control, except for M. citrata treated with no difference in α-NA or GST activity, the activities of ESTs and GST in other treatment groups were significantly increased. Additionally, our results found that Mentha spp. EOs and their major constituents inhibited the activity of AChE in vivo and in vitro. Finally, we performed a structure-based virtual screening of linalool, menthol, and carvone to identify that linalool had the greatest potential to bind to the active site of AChE. The present study suggests that Mentha spp. EOs could provide an additional approach for the management of termites over synthetic insecticides.

Suppression of epithelial proliferation and tumorigenesis by immunoglobulin A.

Immunoglobulin A (IgA) is the most abundant antibody isotype produced across mammals and plays a specialized role in mucosal homeostasis 1 . Constantly secreted into the lumen of the intestine, IgA binds commensal microbiota to regulate their colonization and function 2,3 , with unclear implications for health. IgA deficiency is common in humans but is difficult to study due to its complex etiology and comorbidities 4-8 . Using genetically and environmentally controlled mice, here we show that IgA-deficient animals have a baseline alteration in the colon epithelium that increases susceptibility to multiple models of colorectal cancer. Transcriptome, imaging, and flow cytometry-based analyses revealed that, in the absence of IgA, colonic epithelial cells induce antibacterial factors and accelerate cell cycling in response to the microbiota. Oral treatment with IgA was sufficient to suppress aberrant epithelial proliferation independently of bacterial binding, suggesting that IgA provides a feedback signal to epithelial cells in parallel with its known roles in microbiome shaping. In a primary colonic organoid culture system, IgA directly suppresses epithelial growth. Conversely, the susceptibility of IgA-deficient mice to colorectal cancer was reversed by Notch inhibition to suppress the absorptive colonocyte developmental program, or by inhibition of the cytokine MIF, the receptor for which was upregulated in stem cells of IgA-deficient animals. These studies demonstrate a homeostatic function for IgA in tempering physiological epithelial responses to microbiota to maintain mucosal health.

Spatially Explicit Modeling of Anthropogenic Heat Intensity in Beijing Center Area: An Investigation of Driving Factors with Urban Spatial Forms.

The escalation of anthropogenic heat emissions poses a significant threat to the urban thermal environment as cities continue to develop. However, the impact of urban spatial form on anthropogenic heat flux (AHF) in different urban functional zones (UFZ) has received limited attention. In this study, we employed the energy inventory method and remotely sensed technology to estimate AHF in Beijing's central area and utilized the random forest algorithm for UFZ classification. Subsequently, linear fitting models were developed to analyze the relationship between AHF and urban spatial form indicators across diverse UFZ. The results show that the overall accuracy of the classification was determined to be 87.2%, with a Kappa coefficient of 0.8377, indicating a high level of agreement with the actual situation. The business/commercial zone exhibited the highest average AHF value of 33.13 W m-2 and the maximum AHF value of 338.07 W m-2 among the six land functional zones, indicating that business and commercial areas are the primary sources of anthropogenic heat emissions. The findings reveal substantial variations in the influence of urban spatial form on AHF across different UFZ. Consequently, distinct spatial form control requirements and tailored design strategies are essential for each UFZ. This research highlights the significance of considering urban spatial form in mitigating anthropogenic heat emissions and emphasizes the need for customized planning and renewal approaches in diverse UFZ.

Banks, emissions, and environmental impacts of China's ozone depletion substances and hydrofluorocarbon substitutes during 1980-2020.

Ozone-depleting substances (ODSs), which also contribute to global warming, have been controlled by the Montreal Protocol (MP) since 1987. China joined the MP in 1991 and began reducing production and consumption of ODSs in the country, leading to a decrease in emissions of ODSs. Based on the Intergovernmental Panel on Climate Change guidelines, the latest emission factors and actual consumption in China (MP scenario), both the historical banks and the historical emissions of ODSs and substitute hydrofluorocarbons (HFCs) during 1980-2020 were calculated. To understand the reduction in ODS and HFC emissions by implementing the MP, we also estimated China's virtual emissions (NMP, i.e., the amount of ODS emissions without the MP) over the same period. The avoided cumulative ODS consumption and emission values of 10.8 and 5.8 (4.8-6.9) million tonnes (Mt) of CFC-11-equivalent (eq), respectively, were estimated by comparing the two scenarios. Furthermore, 26 (22-33) giga tonnes (Gt) of CO2-eq emissions, equivalent to an increase of 0.031 W m-2 radiative forcing, were estimated to be avoided by 2020, which will prevent an additional 0.025 °C increase in temperature. The MP implemented by China has resulted in substantial environmental benefits over the last 30 years. However, owing to the massive use of HFCs as substitutes, the cumulative emissions reached 2286 Mt. CO2-eq during 1990-2020, and it will be challenging to phase down HFCs in the environment after China ratified the Kigali Amendment in 2021.

An Acyl Carrier Protein Gene Affects Fatty Acid Synthesis and Growth of Hermetia illucens.

Acyl carrier protein (ACP) is an acyl carrier in fatty acid synthesis and is an important cofactor of fatty acid synthetase. Little is known about ACP in insects and how this protein may modulate the composition and storage of fatty acids. We used an RNAi-assisted strategy to study the potential function of ACP in Hermetia illucens (Diptera: Stratiomyidae). We identified a HiACP gene with a cDNA length of 501 bp and a classical conserved region of DSLD. This gene was highly expressed in the egg and late larval instars and was most abundant in the midgut and fat bodies of larvae. Injection of dsACP significantly inhibited the expression level of HiACP and further regulated the fatty acid synthesis in treated H. illucens larvae. The composition of saturated fatty acids was reduced, and the percentage of unsaturated fatty acids (UFAs) was increased. After interfering with HiACP, the cumulative mortality of H. illucens increased to 68.00% (p < 0.05). H. illucens growth was greatly influenced. The development duration increased to 5.5 days, the average final body weights of larvae and pupae were decreased by 44.85 mg and 14.59 mg, respectively, and the average body lengths of larvae and pupae were significantly shortened by 3.09 mm and 3.82 mm, respectively. The adult eclosion rate and the oviposition of adult females were also severely influenced. These results demonstrated that HiACP regulates fatty acid content and influences multiple biological processes of H. illucens.

Toxicity and Physiological Effects of Nine Lamiaceae Essential Oils and Their Major Compounds on Reticulitermes dabieshanensis.

The volatile metabolites of Salvia sclarea, Rosmarinus officinalis, Thymus serpyllum, Mentha spicata, Melissa officinalis, Origanum majorana, Mentha piperita, Ocimum basilicum and Lavandula angustifolia were determined by gas chromatography-mass spectrometry. The vapor insecticidal properties of the analyzed essential oils and their compounds were screened using Reticulitermes dabieshanensis workers. The most effective oils were S. sclarea (major constituent linalyl acetate, 65.93%), R. officinalis (1,8-cineole, 45.56%), T. serpyllum (thymol, 33.59%), M. spicata (carvone, 58.68%), M. officinalis (citronellal, 36.99%), O. majorana (1,8-cineole, 62.29%), M. piperita (menthol, 46.04%), O. basilicum (eugenol, 71.08%) and L. angustifolia (linalool, 39.58%), which exhibited LC50 values ranging from 0.036 to 1.670 µL/L. The lowest LC50 values were recorded for eugenol (0.060 µL/L), followed by thymol (0.062 µL/L), carvone (0.074 µL/L), menthol (0.242 µL/L), linalool (0.250 µL/L), citronellal (0.330 µL/L), linalyl acetate (0.712 µL/L) and 1,8-cineole (1.478 µL/L). The increased activity of esterases (ESTs) and glutathione S-transferase (GST) were observed but only alongside the decreased activity of acetylcholinesterase (AChE) in eight main components. Our results indicate that S. sclarea, R. officinalis, T. serpyllum, M. spicata, M. officinalis, O. marjorana, M. piperita, O. basilicum and L. angustifolia essential oils (EOs) and their compounds, linalyl acetate, 1,8-cineole, thymol, carvone, citronellal, menthol, eugenol and linalool could be developed as control agents against termites.

The complete mitochondrial genome of Nasutitermes tiantongensis Zhou et Xu, 1993 (Isoptera: Termitidae: Nasutitermitinae).

Nasutitermes tiantongensis belongs to Nasutitermitinae and its mitochondrial genome was determined in this study. It consisted of 13 PCGs, 22 tRNAs, 2 rRNAs, and an A + T-rich control region, and its length was 15824 bp. The phylogenetic analysis suggested that the genus Nasutitermes was not monophyletic, and N. tiantongensis formed a sister group with Bultitermes laticephalus. The mitochondrial genome of N. tiantongensis provides a resource for evolutionary analysis within Nasutitermitinae.

Toxicity, Behavioral Effects, and Chitin Structural Chemistry of Reticulitermes flaviceps Exposed to Cymbopogon citratus EO and Its Major Constituent Citral.

Botanical pesticides are considered the most promising alternative to synthetic pesticides, considering their less negative impacts on the environment and human health. Here, we analyzed the components of lemongrass Cymbopogon citratus essential oil (EO) and evaluated its vapor activity against Reticulitermes flaviceps, in terms of the walking and gripping abilities of workers. In addition, the effects of lemongrass EO and its major component on the cuticular content and structure of chitin in termites were also observed. Our results indicate that cis-citral (36.51%) was the main constituent of lemongrass. In the vapor toxicity assay, the LC50 values of lemongrass EO and citral were 0.328 and 0.177 µL/L, respectively. When worker antennae were treated with lemongrass EO and citral, their walking and gripping capabilities were significantly inhibited. In addition, the cuticular content, thermal stability, and crystallinity of chitin in the termites were decreased after treatment with citral. Collectively, this study provides a basis for developing and utilizing lemongrass and citral as a new environment-friendly insecticide resource to control R. flaviceps.

The lipoxygenase gene OsRCI-1 is involved in the biosynthesis of herbivore-induced JAs and regulates plant defense and growth in rice.

The pathway mediated by jasmonic acid (JA), biosynthesized via 13-lipoxygenases (LOX), plays a central role in both plant development and defense. In rice, there are at least fourteen 13-LOXs. Yet, only two 13-LOXs have been known to be involved in the biosynthesis of JA and plant defenses in rice. Here we cloned a chloroplast-localized 13-LOX gene from rice, OsRCI-1, whose transcripts were upregulated following infestation by brown planthopper (BPH, Nilaparvata lugens), one of the most important pests in rice. Overexpression of OsRCI-1 (oeRCI lines) increased levels of BPH-induced JA, jasmonate-isoleucine, trypsin protease inhibitors and three volatile compounds, 2-heptanone, 2-heptanol and α-thujene. BPHs showed a decreased colonization, fecundity and mass, and developed slowly on oeRCI plants compared with wild-type (WT) plants. Moreover, BPH-infested oeRCI plants were more attractive to the egg parasitoid of BPH, Anagrus nilaparvatae than equally treated WT plants. The decreased attractiveness to BPH and enhanced attractiveness to the parasitoid of oeRCI plants correlated with higher levels of BPH-induced 2-heptanone and 2-heptanol, and 2-heptanone, respectively. Compared with oeRCI plants, WT plants had higher plant height and 1000-grain weight. These results indicate that OsRCI-1 is involved in herbivore-induced JA bursts and plays a role in plant defense and growth.

Influence of nitrate/nitrite on the degradation and transformation of triclosan in the UV based disinfection.

This study investigated the influence of nitrate/nitrite on the degradation and transformation pathway of triclosan (TCS) in UV, UV/peracetic acid (PAA) and UV/HClO processes. The results indicated that the function of nitrate/nitrite significantly depended on the UV source and wavelength, especially nitrate. Generally, the presence of nitrate decreased the direct photo-degradation of TCS in the UV based disinfection. In the LED-UV and LED-UV/HClO processes, the presence of nitrate improved the radical oxidation, and transformation pathway of TCS was varied accordingly. However, nitrate more played a role of photo-competitor in the UV/PAA process, and the reactive nitrogen species (RNS) was difficult to participant in the degradation of TCS due to low redox potential. Compared to nitrate, the presence of nitrite decreased the degradation of TCS in three different UV based disinfection processes. Under UV irradiation, nitrite primarily acted as an irradiation competitor and radical scavenger. Thus, the indirect photo-degradation of TCS was reduced. Noticeably, nitrate/nitrite were the improtant precersors of nitrogenous products in the UV base disinfection. Many new nitrogenous products were identified. But RNS preferentially reacted with the intermediates by -NO2 addition compared to directly reacted with TCS.

Enterococcal symbionts of caterpillars facilitate the utilization of a suboptimal diet.

Bacterial gut symbionts of insect herbivores can impact their host through different mechanisms. However, in most lepidopteran systems we lack experimental examples to explain how specific members of the gut bacterial community influence their host. We used fall armyworm (Spodoptera frugiperda) as a model system to address this objective. We implemented axenic and gnotobiotic techniques using two semi-artificial diets with pinto bean and wheat germ-based components. Following an initial screen of bacterial isolates representing different genera, larvae inoculated with Enterococcus FAW 2-1 exhibited increased body mass on the pinto bean diet, but not on the wheat germ diet. We conducted a systematic bioassay screening of Enterococcus isolated from fall armyworm, revealing they had divergent effects on the hosts' usage pinto bean diet, even among phylogenetically similar isolates. Dilution of the pinto bean diet revealed that larvae performed better on less-concentrated diets, suggesting the presence of a potential toxin. Collectively, these results demonstrate that some gut microorganisms of lepidopterans can benefit the host, but the dietary context is key towards understanding the direction of the response and magnitude of the effect. We provide evidence that gut microorganisms may play a wider role in mediating feeding breadth in lepidopteran pests, but overall impacts could be related to the environmental stress and the metabolic potentials of the microorganisms inhabiting the gut.

A new testing platform using fingerstick blood for quantitative antibody response evaluation after SARS-CoV-2 vaccination.

Testing and vaccination have been major components of the strategy for combating the ongoing COVID-19 pandemic. In this study, we have developed a quantitative anti-SARS-CoV-2 spike (S1) IgG antibody assay using a fingerstick dried blood sample. We evaluated the feasibility of using this high-throughput and quantitative anti-SARS-CoV-2 spike (S1) IgG antibody testing assay in vaccinated individuals. Fingerstick blood samples were collected and analyzed from 137 volunteers before and after receiving the Moderna or Pfizer mRNA vaccine. Anti-SARS-CoV-2 S1 IgG antibody could not be detected within the first 7 days after receiving the first vaccine dose, however, the assay reliably detected antibodies from day 14 onwards. In addition, no anti-SARS-CoV-2 nucleocapsid (N) protein IgG antibody was detected in any of the vaccinated or healthy participants, indicating that the anti-SARS-CoV-2 S1 IgG assay is specific for the mRNA vaccine-induced antibodies. The S1 IgG levels detected in fingerstick samples correlated with the levels found in venous blood plasma samples and with the efficacy of venous blood plasma samples in the plaque reduction neutralization test (PRNT). The assay displayed a limit of quantification (LOQ) of 0.59 µg/mL and was found to be linear in the range of 0.51-1000 µg/mL. Finally, its clinical performance displayed a Positive Percent Agreement (PPA) of 100% (95% CI: 0.89-1.00) and a Negative Percent Agreement (NPA) of 100% (95% CI: 0.93-1.00). In summary, the assay described here represents a sensitive, precise, accurate, and simple method for the quantitative detection and monitoring of post-vaccination anti-SARS-CoV-2 spike IgG responses.

Establishment of HCFC-22 National-Provincial-Gridded Emission Inventories in China and the Analysis of Emission Reduction Potential.

Due to chlorodifluoromethane's (CHClF2, HCFC-22) dual environmental impact on climate change and ozone depletion, its emissions have attracted international attention. In this study, a set of national-provincial-gridded (1° × 1°) emission estimation methods were built and applied to obtain the national, provincial, and gridded emission inventories in China in 1990-2019. In addition, the HCFC-22 emission reduction potential of different emission scenarios was analyzed. The results show that China's HCFC-22 emissions reached a peak in 2017 and that the cumulative emissions in 1990-2019 were 1576.8 (1348.2-1819.0) kt (equivalent to 86.7 kt CFC-11 and 2854.1 Mt CO2). China's HCFC-22 emissions in the east were higher than those in the west, and the emissions in the south were higher than those in the north. Under the control of the Montreal Protocol, China will reduce the cumulative emissions of 17 840.8 kt (avoiding 0.08° of global warming by 2056) in 2020-2056. If the disposal refrigerant can be effectively recycled in the future, the HCFC-22 emission reduction in this period will reach 18 020.3 kt. The established emission estimation methods and obtained results can provide scientific and technological support for ozone layer protection and for addressing climate change.

A high-throughput microsphere-based immunoassay of anti-SARS-CoV-2 IgM testing for COVID-19 diagnostics.

The pandemic of novel coronavirus disease COVID-19 is rapidly expanding across the world. A positive result of antibody tests suggests that the individual has potentially been exposed to SARS-CoV-2, thus allowing to identify asymptomatic infections and determine the seroprevalence in a given population. The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgM antibody detection on the Luminex MAGPIX platform. Clinical agreement studies were performed in 42 COVID-19 patient serum samples and 162 negative donor serum/plasma samples. Positive percent agreement (PPA) was 42.86% (95% CI: 9.90% to 81.59%), 71.43% (95% CI: 29.04% to 96.33%), and 28.57% (95% CI: 13.22% to 48.67%) for samples collected on 0-7 days, 8-14 days, and 2-8 weeks from symptom onset, respectively. Negative Percent Agreement (NPA) was 97.53% (95% CI: 93.80% to 99.32%). There was no cross-reactivity with the SARS-CoV-2 IgG antibody. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL), triglyceride (250 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. In conclusion, an anti-SARS-CoV-2 IgM antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up the anti-SARS-CoV-2 IgM testing.

Multiple Mating of Aphelinus asychis Enhance the Number of Female Progeny but Shorten the Longevity.

The Aphelinus asychis female adult is an important arrhenotocous parthenogenesis parasitoid of Myzus persicae, and its reproductive mode is beneficial for the population continuation of A. asychis by way of multiple mating and backcross. To explore the effect of mating on the population fitness and control efficiency of A. asychis, its mating frequency and backcross were observed under laboratory conditions. The results showed that most matings in A. asychis involved four distinct stages: courtship, pre-copulatory, copulation, and post-copulatory behaviours. Only the duration of courtship increased significantly with an increase in copulation frequency for females, and the courtship duration of A. asychis females mated with different males were significantly shorter than those mated with the same male at the same mating times, which suggested that A. asychis females might prefer to mate with different males to enrich the genotype of their offspring. The total number of mummified aphids and the female and male longevity decreased significantly with an increase in mating frequency. On the contrary, female progenies increased significantly with an increase of mating frequency, suggesting that sperm limitation might occur in females when they only mated once. These results imply that females might prefer to receive more sperm by mating multiple times in their life span. In addition, we found that the intrinsic rate of increase (r) of A. asychis of the control group (0.2858 d-1) was significantly greater than that in the backcross treatment (0.2687 d-1). The finite killing rate (θ) of A. asychis of the control group was similar to that in the backcross treatment, which showed that this treatment had a negligible negative effect on the control efficiency of A. asychis. In conclusion, the results showed that multiple mating increased the number and proportion of A. asychis female progenies but shortened the longevity of female and male adults, while the negative effect of backcross on the control efficiency of A. asychis was negligible.

The complete mitochondrial genome of Reticulitermes ovatilabrum (Isoptera: Rhinotermitidae).

The mitochondrial genome of the Reticulitermes ovatilabrum is 15,913 bp in length and encodes 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and a non-coding control region (D-loop). The percentage of A/T (65.59%) is much higher than that of C/G (34.41%). The phylogenetic tree revealed that R. ovatilabrum was closest to R. kanmonensi and R. periflaviceps. The mitochondrial genome of the R. ovatilabrum provides a resource for evolutional analysis within termites especially Reticulitermes.

A high-throughput Anti-SARS-CoV-2 IgG testing platform for COVID-19.

BACKGROUND: Serology tests for detecting the antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can identify previous infection and help to confirm the presence of current infection. OBJECTIVE: The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgG antibody detection. RESULTS: Clinical agreement studies were performed in 107 COVID-19 patient serum samples and 226 negative donor serum/plasma samples. Positive percent agreement (PPA) was 46.15 % (95 % CI: 19.22 % ∼74.87 %), 61.54 % (95 % CI: 31.58 % ∼86.14 %), and 97.53 % (95 % CI: 91.36 % ∼99.70 %) for samples collected on 0-7 days, 8-14 days, and ≥15 days from symptom onset, respectively. Negative Percent Agreement (NPA) was 98.23 % (95 % CI: 95.53 % ∼99.52 %). No cross-reactivity was observed to patient samples positive for IgG antibodies against the following pathogens: HIV, HAV, HBV, RSV, CMV, EBV, Rubella, Influenza A, and Influenza B. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. CONCLUSION: An anti-SARS-CoV-2 IgG antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up anti-SARS-CoV-2 IgG testing.

Toxicity of the essential oil from Thymus serpyllum and thymol to larvae and pupae of the housefly Musca domestica L. (Diptera: Muscidae).

The essential oil (EO) of Thymus serpyllum and thymol were evaluated for their insecticidal activity against the housefly (Musca domestica) larvae and pupae. Contact toxicity and fumigation bioassays were used. Chemical composition analysis of T. serpyllum EO by gas chromatographic mass spectrometry (GC-MS) revealed that thymol (41.6%), p-cymene (21.9%), and γ-terpinene (19.2%) were the major components. For larval assays, the LC50 value of T. serpyllum EO was 0.4 µl/cm2 for contact toxicity and 20.9 µl/l for fumigation toxicity. For thymol, the contact toxicity LC50 value was 0.035 µl/cm2 and the fumigation LC50 value was 2.0 µl/l. For the pupal assay, T. serpyllum EO had a percentage inhibition rate (PIR) value of 100% for both contact toxicity (1.0 µl/cm2) and fumigation toxicity assay (25 µl/l), whereas thymol had a PIR of 100% for contact toxicity (0.1 µl/cm2) and fumigation assay (5 µl/l). This study shows that T. serpyllum EO and thymol are toxic to housefly larvae and pupae and have the potential for use in the population control of this species.