Discrimination of ACCase-inhibiting herbicides-resistant Digitaria ciliaris populations with three diagnostic bioassays

In the field of modified release, this review covers the detail aspect of a novel pulsatile drug delivery systems (PDDS) by oral administration that aims to release drugs on a programmed pattern at specific time and specific site as per the pathophysiological need of the disease, resulting in improved patient therapeutic efficacy and compliance. In particular, the recent literature reports on a variety of pulsatile release systems intended for the oral route, which have been recognised as potentially beneficial to the chronotherapy of widespread diseases. Asthma, peptic or deodenal ulcer, diabetes, neurological disorder, hypertension, cardiovascular diseases, arthritis, attention deficit syndrome in children, and hypercholesterolemia these kind of diseases are promising by pulsatile drug delivery. Technically, This system is designed for chronopharmacotherapy which is based on circadian rhythm and beneficial for the drugs having chronopharmacological behavior where night time dosing is required and for the drugs having high first-pass effect and specific site of absorption in gastrointestinal tract. This controlled–release system can maintain the drug concentration within the therapeutic window with a single dose, which lowers the systemic drug level and also preserves medication that rapidly destroyed by the body. Pulsatile drug delivery system is time related or site-specific related to drug released at the desired site within the intestinal tract (e.g., the colon). Pulsatile drug delivery systems are formulated when zero order drug release is not desired. Based on these premises, the aim of this review is to outline the rational and prominent design strategies behind oral pulsatile delivery. Capsular systems, osmotic systems, soluble or erodible polymer coating and rupturable membranes etc. are summarized in this pulse article. Various marketed technologies on pulsatile drug delivery like OROS, PULSINCAP, GEOCLOCK, SODAS, CODAS, etc., were launched by pharmaceutical companies.

Effect of malathion on resistance to soil-applied herbicides in a population of rigid ryegrass (<i>Lolium rigidum</i>)

Fitness cost and reversion of resistance Leucoptera coffeella (Lepidoptera: Lyonetiidae) to chlorpyrifos

Investigations of 2,4-D and Multiple Herbicide Resistance in a Missouri Waterhemp (<i>Amaranthus tuberculatus</i>) Population

Molecular experiment was conducted to confirm resistant to aryloxyphenoxypropionate herbicides in winter wild oat (Avena ludoviciana Duriu.) populations of wheat fields in Khuzestan province, at Faculty of Agriculture of Ferdowsi University, during year of 2006. First, 44 wild oat populations from Ahvaz, Andimeshk, Shush, Shushtar, Ramhormoz, Susangerd, and Dezful cities with a susceptible population were examined in screening experiments. According to these experiments, 37 populations of winter wild oat biotypes selected as suspected resistance populations, and used for molecular experiment to determine resistance mechanism. dCAPS method was carried out in three steps consisting of PCR, enzyme digestion, and gel electrophoresis. Results showed that mutation at position 1781 of ACCase enzyme resulted in resistance in 10 winter wild oat populations from Andimeshk (5), Shush (1), Shushtar (2), and Susangerd (2) to clodinafop propargyl, diclofop methyl, and fenoxaprop p ethyl herbicides. While, in other suspected resistance populations other mechanism such as metabolism is probable. Also, it was concluded that this method is a good technique to detect herbicide resistance and mechanism of herbicide resistance in winter wild oat.

1. Anticoccidials are widely used as food additives to prevent and treat coccidiosis. They are licensed for use in a prescribed concentration and during a specific time interval with broilers and pullets, but not for laying hens. 2. This study was set up to develop a new high pressure liquid chromatography (HPLC) method to detect clazuril (CZ: (±)-2-chloro-α-(4-chlorophenyl)-4-(4,5-dihydro-3,5-dioxo-1,2,4-triazin-2(3H)-yl)-benzeneacetonitrile) in egg yolk and albumen and in plasma; to investigate both the presence of residues of CZ in eggs and its pharmacokinetic behaviour in laying hens. 3. A single oral dose (3 mg/kg BW) and multiple oral doses (3 mg/kg BW for 5 d) were investigated. The analytical method gave very good recovery (64 to 74%) in the three different matrices (yolk, albumen and plasma); precision and accuracy were within 11%. 4. After a single dose no residue was detected in eggs collected for up to 10 d, while following multiple dose treatment, CZ residues were detected until 10 d after the end of treatment. The concentration of the drug was higher in yolk than in albumen with a maximum ratio of 10 : 1. 5. Pharmacokinetics of CZ in laying hens after a single dose showed a detectable concentration of the drug up to 24 h. It reached a steady state after the third administration in multiple dosing. 6. Although further studies are necessary, these results indicate that a single oral dose of CZ could be used as an anticoccidial for laying hens due to the lack of residues in eggs.

Aedes albopictus is the primary vector of major arboviral diseases such as dengue fever, chikungunya fever, and Zika virus disease, and its control is highly dependent on chemical insecticides. However, the long-term use of pyrethroid insecticides has led to the development of insecticide resistance in Ae. albopictus, which severely undermines the efficacy of vector control programs. Ae. albopictus populations were collected from five sites in Guangdong and Hainan provinces, China. Beta-cypermethrin resistance levels were determined via bioassays, with resistance ratios at the median lethal concentration (RR50) calculated. Target-site resistance was evaluated via kdr mutation detection in the voltage-gated sodium channel (VGSC) gene. Transcriptome sequencing identified differentially expressed genes (DEGs), and 16S rRNA sequencing characterized gut microbiome alterations. Correlation analysis and Cedecea neteri dietary supplementation assays verified the role of gut microbiota in resistance. The results showed that all four populations (except the CP population) exhibited varying degrees of resistance to beta-cypermethrin, with resistance ratios at the median lethal concentration (RR50) ranging from 2.84 to 29.18. Detection of kdr mutations revealed three mutations (F1534C, F1534L, F1534S) at codon 1534 of the voltage-gated sodium channel (VGSC) gene in all field populations, with mutation frequencies ranging from 49.4% to 100.0%, and a low-frequency V1016G mutation at codon 1016. Transcriptome analysis identified a total of 2,566 commonly upregulated genes and 994 commonly downregulated genes across the resistant populations. Gut microbiome analysis revealed a significant alteration in the intestinal microbial community structure of resistant populations; specifically, the relative abundance of the genus Cedecea differed significantly between resistant and susceptible populations and correlated strongly with the expression of most differentially expressed genes. Furthermore, dietary supplementation with Cedecea neteri significantly increased the survival rate of Ae. albopictus exposed to β-cypermethrin (73.86% vs 40.00%; P < 0.0001). From the perspectives of target-site mutations, gene expression regulation, and gut microbe interactions, this study providing a foundation for further studies on resistance mechanisms in Ae. albopictus, thereby providing a theoretical foundation for further dissection of resistance mechanisms and optimization of vector control strategies.

Insect natural enemies can develop resistance to insecticides in the field like their host insects. Recently, a high level of resistance to several groups of insecticides from Pakistan has been shown in Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). Here, we were interested to determine the impact of insecticides resistance on fitness of various populations of C. carnea collected over three consecutive years (2005-2007) from different areas of Pakistan. The populations were examined for intrinsic rate of population increase, growth index, fertility, eggs viability, survival to adult hood and doubling time. The results of the study showed significantly higher intrinsic rate of population increase in insecticides resistant population compared with laboratory susceptible population Lab-PK. Similarly, the resistant population laid more numbers of eggs, which were significantly more viable than susceptible population. The survival to adulthood and doubling time were greater in field populations than the susceptible. The most intriguing finding was that the predation potential of all resistant populations was significantly great compared with Lab-PK. The data point to the fact that resistance to insecticides had positive impact on C. carnea, which could be used in integrated pest management system. The potential for introducing these natural enemies into cropping systems where they have not developed resistance could be a useful tactic for management of various insect pests.

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), poses a significant threat to global tomato production. However, environmentally sustainable management strategies for this pest, as well as its mechanisms of insecticide resistance, remain insufficiently understood. Broflanilide, a novel meta-diamide compound, can bind specifically to the transmembrane domain of the RDL subunit, causing prolonged opening of the chloride channel, disruption of neurotransmission, and ultimately insect paralysis and death. This study employed the leaf immersion method to conduct bioassays on the second-instar larvae of T. absoluta to evaluate physiological responses to sublethal concentrations of the novel amide insecticide broflanilide. Subsequently, high-throughput transcriptome sequencing was performed to investigate changes in gene expression and metabolic pathways. Bioassay results determined the larval sublethal concentrations of broflanilide to be 0.136 mg/L (LC10) and 0.210 mg/L (LC30). Sublethal exposure significantly prolonged the larval period, reduced pupal weight, and inhibited fecundity of female adults. Transcriptomic and qPCR analyses revealed that, compared with the control (CK), expression of the vitellogenin gene Vg decreased by 15.99% and 30.27% under LC10 and LC30 treatments, respectively, while its receptor gene VgR decreased by 11.56% and 24.49%. Similarly, expression of chitin synthase genes chs1 and chs2 declined by 13.56% and 30.17% (chs1), and 7.85% and 19.45% (chs2), respectively. Gene expression analysis elucidated how sublethal insecticides treatment impact larval development and fecundity. Furthermore, the study revealed upregulation of cytochrome P450-mediated detoxification pathways and Toll/Imd immune signaling pathways under broflanilide stress, indicating activation of a coordinated defense response in T. absoluta. Sublethal broflanilide exposure modulated larval gene expression to balance growth, development, and stress adaptation. Such exposure exerts selective pressure on susceptible populations, potentially driving adaptive shifts in detoxification metabolism and contributing to the development of field resistance. These findings advance our understanding of the sublethal effects of novel insecticides and provide valuable insights for insecticide deployment strategies and resistance management.

Functions of insect CYP2 clan P450s in insecticide resistance are relatively less reported. In Spodoptera litura, a gene from the CYP2 clan (CYP304F1) was validated to be up-regulated significantly in a pyrethroid- and organophosphate-resistant population (QJ) than a susceptible population by RNA-Seq and qRT-PCR. Spatial-temporal expression indicated the high expression of CYP304F1 in the fourth, fifth, and sixth instar larvae and the metabolism-related tissue fat body and malpighian tubules. CYP304F1 was knocked out by CRISPR/Cas9, and a homozygous population (QJ-CYP304F1) with a G-base deletion at exon 2 was obtained after selection. Bioassay results showed that the LD50 values to β-cypermethrin and chlorpyrifos in the QJ-CYP304F1 population decreased significantly, and the resistance ratio was both 1.81-fold in the QJ population compared with that in the QJ-CYP304F1 population. The toxicity of fenvalerate, cyhalothrin, or phoxim showed no significant change. These results suggested that CYP304F1 is involved in β-cypermethrin and chlorpyrifos resistance in S. litura.

Glutathione S transferases (GSTs) are multifunctional enzymes involved in detoxification of xenobiotic compounds in majority of the insect groups. Significance of insect GSTs is their elevated level of activity in association with insecticide resistance. This investigation was to explore the metabolic status of GSTs in two Indian DDT-resistant malaria vectors, Anopheles culicifacies and Anopheles annularis, and one DDT-susceptible vector, Anopheles fluviatilis. Malkangiri and Koraput districts of Orissa State, endemic for falciparum malaria and having a long insecticide spraying history, were the study areas. F1 progeny was raised from wild-caught females of the three vectors and used for biochemical assays to detect the GST-mediated DDT resistance mechanism. Results of the enzyme assay showed a significant 3-fold increase in GST activity in DDT-resistant An. annularis compared with its susceptible population. In DDT-resistant An. culicifacies, the median GST activity (71.8 micromol/min/mg) was almost the same as estimated in the DDT-resistant An. annularis (74.6 micromol/ min/mg), suggesting that the GST activity estimated in An. culicifacies could be an elevated level for detoxification of DDT. Furthermore, the GST activity in DDT-resistant An. culicifacies and An. annularis was significantly higher than that in the DDT-susceptible An. fluviatilis, which had a GST activity of 20.0 micromol/min/mg. Also, the GST-mediated DDT detoxification was confirmed by comparing GST activity in wild-caught females with that in their F1 progeny.

Herbicide Resistance in Rigid Ryegrass (<i>Lolium rigidum)</i>Has Not Led to Higher Weed Densities in Western Australian Cropping Fields

The sudden invasion of the tomato leaf miner, Tuta absoluta Meyrick into tomato crops in Nigeria in 2015 has led to the extensive use of common insecticides, together with the introduction of a new insecticide referred to as “Tuta solution”, as only control method. After two years the farmers in major tomato producing states of Nigeria (Kaduna, Kano and Katsina States) reported that most of the insecticides applied were no longer effective in controlling Tuta. This led to the investigation of the toxicities of common insecticides lambda-cyhalothrin (MoA group 3A) and deltamethrin (MoA group 3A), and of the newly introduced formulations of chlorantraniliprole + lambda-cyhalothrin (MoA group 28 + 3A) and spirotetramat + flubendiamide (MoA group 23 + 28). These insecticides were tested on larvae obtained from populations collected from major tomato-growing states (Bomo and Giwa in Kaduna State; Beriberi and Funtua in Katsina State; and Bagauda, Watari and Samawa in Kano State) and a susceptible laboratory population of the National Horticultural Research Institute (NIHORT), Ibadan, Nigeria. These populations were subjected to concentration mortality bioassays, according to susceptibility test method No. 022, devised by the Insecticide Resistance Action Committee (IRAC). Resistance to chlorantraniliprole + lambda-cyhalothrin, lambda-cyhalothrin, and deltamethrin were observed in all the populations and compared with that of the susceptible NIHORT population. The resistance ratios obtained within the 7 populations ranged from 4.09 to 16.97 for chlorantraniliprole + lambda-cyhalothrin, 2.66 to 7.88 for lambda-cyhalothrin, and 3.23 to 6.24 for deltamethrin. However, resistance to spirotetramat + flubendiamide was not observed in all the 7 populations, with resistance ratio value of 1.05 as this combination was only introduced in 2017 for the control of T. absoluta in Nigeria and differently from the others, has not yet been abused. The sole dependence on, and indiscriminate usage of insecticides by farmers due to reckless recommendations, without regard for Integrated Pest Management, resulted in the widespread, higher levels of resistance observed in chlorantraniliprole + lambda-cyhalothrin, a product recently introduced into Nigeria in 2015.

Structure identification of circulating metabolites from somapacitan, a long-acting growth hormone derivative, and pharmacokinetics after single and multiple subcutaneous dosing in rats

Following the application of MCPA/MCPB at 1.7 kg ae ha−1 at a field site near Dresden, ON, Canada, poor control (&lt;50% visible control) of green pigweed (Amaranthus powellii S. Watson) was observed. Amaranthus powellii is a common weed in Ontario crop production, and its evolution of resistance to synthetic auxin herbicides (SAHs) could pose a risk to crop yields. The suspected resistant A. powellii population (R) was used in dose–response and field experiments to determine resistance to SAHs. The objective of these studies was to determine whether this population of A. powellii is resistant to MCPA and cross-resistant to other SAHs. The GR50 (herbicide dose that causes a 50% reduction in plant aboveground biomass) values were determined by fitting plant dry weight data, obtained following application with seven SAHs, to a four-parameter log-logistic equation and were compared between the suspected-resistant (R) population and a known susceptible (S) population of A. powellii. The field trial was conducted in 2017, 2018, 2019, and 2021 in corn (Zea mays L.) and consisted of 11 postemergence SAH treatments. The GR50 values differed between the R and S populations following application with MCPA, aminocyclopyrachlor, dichlorprop-p, and mecoprop, resulting in resistance factors of 4.4, 3.0, 2.5, and 2.4, respectively. In the field study, dicamba and MCPA ester controlled A. powellii 84% and 30%, respectively, at 8 wk after treatment application (WAA). The control of Amaranthus powellii with all SAHs applied POST in corn was poor (&lt;90% visible control) at 8 WAA. Both studies confirmed resistance to SAHs in this population of A. powellii, which will create limitations for farmers aiming to control this weed.