Plants are often exposed to non-ideal conditions during their growth. The toxicity of heavy metals as abiotic stressors is a significant concern due to their harmful effects on plants. Glycine betaine (GB) is a potent compatible solute that helps plants resist abiotic stresses and plays a crucial role in alleviating them. This study aimed to determine the effective role of glycine betaine (0.5 and 1 mM) as a foliar treatment in sugar beet plants to cope with the toxicity of cadmium (50 mg/kg soil) and lead (100 mg/kg soil). The application of lead (Pb) and cadmium (Cd) in cultivation soil noticeably suppressed morphological growth attributes, such as chlorophylls, carotenoids, sugars, and proteins. At the same time, the aforementioned levels of heavy metals significantly increased the levels of non-enzymatic antioxidants (phenolics and proline) and enzymatic antioxidants (peroxidase, superoxide dismutase, polyphenol oxidase, and catalase) in the root and shoot tissues of sugar beet plants. In contrast, the use of glycine betaine as foliar treatment at 0.5 and 1 mM alleviated the adverse impacts of cadmium and lead by promoting the aforementioned attributes. Furthermore, the application of 1 mM GB was more effective in increasing the contents of phenolics in root by approximately 16% and 29%, phenolics in shoot by about 25% and 10%, peroxidase activity by about 82% and 116%, superoxide dismutase activity by about 56% and 47%, polyphenol oxidase activity by about 9% and 36%, catalase activity by about 19% and 25%, in cadmium- and lead-stressed plants, respectively. Additionally, it reduced the levels of proline in sugar beet tissues. Overall, the application of glycine betaine has the efficacy to counteract the adverse impacts of cadmium and lead toxicity on sugar beet plants by enhancing the metabolic indices as well as the non-enzymatic and enzymatic antioxidant activities.
Background: The Aedes aegypti mosquito is the primary vector for dengue, chikungunya, yellow fever and Zika viruses worldwide. The first record of Ae. aegypti in southwestern Saudi Arabia was in 1956. However, the first outbreak and cases of dengue fever were reported in 1994, and cases have increased in recent years. Vector control for Ae. aegypti mainly uses pyrethroid insecticides in outdoor and indoor space spraying. The constant use of pyrethroids has exerted intense selection pressure for developing target-site mutations in the voltage-gated sodium channel (vgsc) gene in Ae. Aegypti against pyrethroids—mutations that have led to knockdown resistance (kdr). Methods: Aedes aegypti field populations from five regions (Jazan, Sahil, Makkah, Jeddah and Madinah) of southwestern Saudi Arabia were genotyped for known kdr mutations in domains IIS6 and IIIS6 of the vgsc gene using polymerase chain reaction (PCR) amplification and sequencing. We estimated the frequency of kdr mutations and genotypes from Saudi Arabia as well as from other countries, Thailand, Myanmar (Southeast Asia) and Uganda (East Africa). We constructed haplotype networks to infer the evolutionary relationships of these gene regions. Results: The three known kdr mutations, S989P, V1016G (IIS6) and F1534C (IIIS6), were detected in all five regions of Saudi Arabia. Interestingly, the triple homozygous wild genotype was reported for the first time in two individuals from the highlands of the Jazan region and one from the Al-Quoz, Sahil region. Overall, nine genotypes comprising four haplotypes were observed in southwestern Saudi Arabia. The median-joining haplotype networks of eight populations from Saudi Arabia, Southeast Asia and East Africa for both the IIS6 and IIIS6 domains revealed that haplotype diversity was highest in Uganda and in the Jazan and Sahil regions of Saudi Arabia, whereas haplotype diversity was low in the Jeddah, Makkah and Madinah regions. Median-joining haplotype networks of both domains indicated selection acting on the kdr-mutation containing haplotypes in Saudi Arabia. Conclusions: The presence of wild type haplotypes without any of the three kdr mutations, i.e. that are fully susceptible, in Saudi Arabia indicates that further consideration should be given to insecticide resistance management strategies that could restore pyrethroid sensitivity to the populations of Ae. aegypti in Saudi Arabia as part of an integrative vector control strategy. Graphical
The synthesis of nanoparticles utilizing green techniques is becoming increasingly important due to its low cost, biocompatibility, high productivity, and eco-friendliness. Herein, the current work focused on the biosynthesis, characterization, and biological applications of zinc oxide nanoparticles (ZnO-NPs) from Anabasis articulata, including antioxidant anticancer and larvicidal properties, as well as modifications to the phytochemical ingredients. Hence, the tannin, phenolic, and flavonoid concentrations of the produced nanoparticle samples were lower than those of the original aqueous extract. When compared to the results of ascorbic acid (12.78 mg/mL), the produced extract of A. articulata and its zinc nanoparticles showed remarkable efficacy as antioxidant agents with IC50 values of 27.48 and 69.53 mg/mL, respectively. A normal lung fibroblast cell line (WI-38) and three tumor cells were used to test the compounds’ anticancer properties. With an IC50 of 21.19 µg/mL, the ZnO-NPs of A. articulata showed the greatest cytotoxicity against HePG-2 cell lines. Additionally, A. articulata zinc nanoparticles showed significant cytotoxicity against MCF-7 and PC3 tumor cell lines, with IC50 values of 30.91 and 49.32 µg/mL. The biogenic ZnO-NPs had LC50 and LC90 values of 13.64 and 26.23 mg/L, respectively, and are very effective against Aedes aegypti larval instar (III). Additionally, the percentages of larval mortality increased from 28.61% at 5 ppm to 84.69% at 25 ppm after 24 h post-treatment. The overall results of this study point to the potential of A. articulata as a substitute biological agent for potential therapeutic/leutic uses in the medical domains and for preventing the proliferation of malarial vector insects.
Amblyseius swirskii are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. Tetranychus urticae is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on A. swirskii, a biological control agent for T. urticae. The present results demonstrated the change in the functional response estimates when A. swirskii was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency (a′) showed the highest value (a′ = 0.919) at 26 °C and the lowest value (a′ = 0.751) at 14 °C. The handling time per prey item (Th) for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C (Th = 0.005) and the highest value at 14 °C (Th = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for A. swirskii showed a significant difference between the mean numbers of T. urticae consumed at various prey densities and temperatures, illustrating a relationship between A. swirskii and T. urticae. Therefore, the results of this research may be utilized to forecast the behavior of A. swirskii and its usefulness in controlling T. urticae populations.
30 October 2023 in Saudi Journal of Biological Sciences
In the current study, the biological effects of various solvents concentrations of Artemisia absinthium were assayed on different stages (larva, pupa and adult) of Aedes aegypti under controlled laboratory conditions. The life initiation and mortality for each insect stage were evaluated. Different lethal concentrations were measured. Aedes aegypti L. was susceptible to all plant extract solvents in different conc. ANOVA test, correlation analysis and simple linear regression were used to evaluate the significance. The results correlated with other comparative studies with different Artemisia sp. to put the studied species in the proper way in Asteraceae family. The study gave A. absinthium L. its bright position as a perfect natural insecticide especially as larvicidal due to the low Lc50 degree. Scientists welcome to use natural insecticide at initial stages of insect not in later ones.
Culex pipiens (Diptera: Culicidae) is a disease vector for the West Nile virus (WNV). Climate change impacts the disease transmission carried by mosquitoes, and it is partly to blame for the resurgence of mosquitoes as important disease vector insects. This study assessed the geographic range of Culex pipiens in the United States under both present and projected climatic scenarios, identifying the primary environmental factors influencing its distribution. Employing species distribution modeling (MaxEnt, Version 3.4.1) and occurrence data from the Global Biodiversity Information Facility, we examined the effects of key variables, including altitude, temperature seasonality (bio4), and annual precipitation (bio12), on habitat suitability for C. pipiens. The analysis revealed that altitude accounted for 60.3% of the model’s explanatory power, followed by temperature seasonality (31%) and annual precipitation (8.7%). Areas having low elevation and moderate temperature fluctuations were the most favorable for C. pipiens, with a predicted range extending across the Midwest and southeastern United States under present variables. Future projections for 2050 and 2070 under Representative Concentration Pathway (climatic change) scenarios suggest possible northward expansion in response to rising temperatures and altered precipitation patterns. The study highlights some shifts in C. pipiens distribution and the potential for increased disease transmission into new areas. This study serves as a catalyst for decision-makers to coordinate their management reaction and create more resilient and comprehensive strategies to safeguard human health.