The objectives of this study are to determine the epidemiological situation of virus infection through the period of pandemic and risk factors associated with COVID-19 infection in Al-Riyayna city of Libya.

Methods

In this retrospective descriptive study were reviewed records of samples collected from November 2020 to October 2021, were analyzed to determine the risk factors Age groups, sex, and monthly weather associated with infection in the city of Al-Riyayna. Statistical analysis was performed using SPSS version 26 descriptive statistics, using chi-square analysis investigate the level of association among variables at the significance level of P≤ 0.05.

Results

The current study reported (1430; 22.1%) positive at (P≤ 0.05), Females showed higher positivity rate compared to males (839; 58.7%, 591; 41.3%) respectively . of all positive COVID-19 cases, most infections occurred in the age groups (15–44 years) as compared to other age groups, the highest number was among age group 25–34 years (330; 23.1%). During study period was two waves of highest positivity rate of COVID-19 cases were recorded, the first wave occurred in November 2020 (250; 17.5%), then the rate begin to decrease until the February 2021 (62; 4.3%). The second wave was in March 2021, the rate of infection increase until April rate reached to 275 cases (19.2%).

Conclusion

Based on our data, have demonstrated the significant effects and high cumulated prevalence of COVID-19 of age and gender. Consequently, it is recommended to take preventative in elderly individuals and asymptomatic cases lies in the fact that it may be  a carrier of the COVID-19 virus,

Malaysia is a country of numerous natural wonders, which include a collection of impressive cave formations. Found all over the country, these caves contain rock art and wall paintings. The samples were collected from wall surfaces painted caves of Niah, Sarawak, and Tempurung, Perak. Three cyanobacterial genera, have been characterized using a polyphasic approach by comparing phenotypic characteristics, using a light microscopy and scanning electron microscopy (SEM). Molecular characteristics, by confirmed their identification based on 16S rRNA gene sequences. The microflora from both sampling locations was represented by three cyanobacteria morphospecies, Synechococcus sp. (18.78%), Gloeocapsa sp. (12.20%), Chroococcus sp. (4.94%). The photomicrographs of all the dominant microalgae recorded. Synechococcus sp. a cylindrical oblong elliptical unicellular or sometimes 2 to 4 cells as a result of cell division. Under SEM Synechococcus sp. cells were cylindrical to oblong 2.6 μm in diameter and 3.8μm long. The cells were enclosed in hyaline mucilage and with cells usually aggregating in large numbers to form colonies. Gloeocapsa sp. cells were spherical, blue- green homogeneous contents, enclosed by wide colorless sheaths, of diameter 2-4μm, with sheaths 4-8μm. Chloroococcus sp. cells were spherical, sometimes hemispherical after division, united cell in colonies of two sheath, sheath is colorless and the individual cells were large; 20-28μm in diameter. According to DNA sequence analysis, cyanobacteria l was closely related to Synechococcus sp, (99% similarity), cyanobacteria ll was found to be similar to Gloeocapsa sp. (97% similarity) and cyanobacteria lll was Chroococcus sp. (95% similarity). This study, used chemicals agents to control cyanobacteria from both sampling locations, by (NaOCl), (Ca(OCl)2) and (H₂O₂). The result showed that, 5% H₂O₂, Ca(OCl)2 and NaOCl gave a significant difference (p˂0.05) on the growth of cyanobacteria. However, the effect of 15% H₂O₂ was not significantly different (p˃0.05) with Ca(OCl)2 and NaOCl at 10, 15, and 30 minutes exposure, only 5 minutes exposure was significant (p˂0.05)

 Background: Caves are unique natural features and habitats where specialized organisms grow. One of the world’s main concerns is that of the conservation and preservation of our cultural heritage, including rock art and wall

paintings within caves.

Methods: This study was conducted by collecting the samples scraped from wall surfaces at 19 different location in painted caves of Niah cave, Sarawak, and Tempurung cave, Perak. Morphospecies identification and genomic DNA polymorphisms were used to identify the two strains of bacteria. The growth was controlled chemical method using sodium hypochlorite (NaOCl), Calcium hypochlorite Ca (OCl) 2 and hydrogen peroxide (H₂O₂).

Results: Morphospecies identification was carried out using a light microscopy and scanning electron microscopy (SEM), both the bacteria, bacteria I and bacteria II were isolated from the soil samples and were Gram-negative bacteria. Based on BLAST search, bacteria I showed 100% with Stenotrophomonas sp (NR 024708.1), and bacteria II showed 100% with Cryptococcus liquefaciens (NR 043289. 1). The growth was controlled chemical method using sodium hypochlorite (NaOCl), Calcium hypochlorite Ca (OCl) 2 and hydrogen peroxide (H₂O₂). The laboratory studies showed that three chemical were effectively eliminated colonies/cells of the both bacteria compared to the colonies found on the control pate this stud

Abstract. Cytochrome P450s (P450s) involved in insecticide resistance reduce the effi cacy of insecticide-based vector control by rendering vector control ineffective. They are recorded in many species of vectors and have various constitutive and insecticide induction profi les. In this study, the isolation and prediction of the structure of a P450 from a strain of Aedes aegypti originating from Malaysia is reported. Quantitative mRNA expression of this gene and a previously reported P450, CYP4H28v2, in the devel opmental stages of the mosquito after exposure to sub-lethal concentrations of insecticides is also reported. The isolated P450, CYP4H31v2, is an allelic variant of CYP4H31 and contains several conserved motifs of P450s. The secondary structure of the protein is mostly made up of alpha helices and random coils. The tertiary structure was generated using homology modeling and was of good quality based on structure validation using protein structure assessment tools. CYP4H28v2 and CYP4H31v2 were differentially expressed in the developmental stages of the vector, with a signifi cantly increased expression in adult males. The genes were signifi cantly over-expressed in larvae exposed to deltamethrin and permethrin for 6 h. In the DDT-treated larvae, only CYP4H31v2 was signifi cantly over-expressed after a 6 h exposure. Under-expression of the genes was predominant in larvae treated with the organophosphates malathion and temephos. Though the functions of these P450s are unknown, their response to induction by exposure to insecticides indicates the likely involvement of these genes in insecticide tolerance.

Objective

To clone cytochrome P450 from Aedes aegypti (Ae. aegypti) and determine the characteristics using bioinformatics tools.

Methods

Cytochrome P450 of Ae. aegypti was amplified using polymerase chain reaction, cloned and sequenced. Evolutionary relationship of the sequence was inferred and bioinformatics tools were used to predict subcellular localisation, signal peptide, transmembrane helix, phosphorylation, O-glycosylation, secondary and tertiary structures of the deduced protein.

Results

Polymerase chain reaction rather amplified a cytochrome P450 pseudogene which was named CYP4H44P (GenBank accession number KF779932). The pseudogene has 1 537 nucleotides and an open reading frame of 335 amino acids containing cytochrome P450 motifs except the WxxxR motif. It is highly homologous to CYP4H28 and CYP4H28v2. Phylogenetic analysis and evolutionary divergence showe

Abstract. Synthetic insecticides and other xenobiotic compounds are usually used to abate the effects of insect pests/vectors of agricultural and medical importance by adversely affecting the insects. The xenobiotics are also capable of inducing the expression of detoxification genes such as the cytochrome P450 (CYP) gene in targeted insects like mosquitoes (Feyereisen, 2012). The high expression levels of CYPs in insecticide-resistant and exposed mosquitoes have been linked with a potential role in xenobiotic resistance. This study investigated the induction potential of leaf litter infusions and insecticides on the expressions of CYP4H28v2 and CYP4H31v2 in the dengue mosquito Aedes aegypti using Reverse Transcription-quantitative Polymerase Chain Reaction. Exposure of Ae. aegypti larvae to leaf litter infusions demonstrated that CYP4H28v2 and CYP4H31v2 were significantly induced by Lagerstroemia speciosa but not Ficus benjamina, Plumeria obtusa, Millettia pinnata and Pithecellobium dulce. None of the genes was significantly highly expressed in adult females exposed to d-allethrin and d-trans allethrin products. CYP4H28v2 was significantly induced in Ae. aegypti exposed to DDT, malathion and permethrin for both 5 and 10 min. DDT, malathion and permethrin significantly induced CYP4H31v2 only in Ae. aegypti exposed to the insecticides for 10 min. Exposure to the insecticides for 5 min displayed different levels of CYP4H31v2 expression with significantly higher (DDT-exposed) and lower (permethrin-exposed) levels in the mosquito. The results show that natural and synthetic xenobiotics can induce significant expression of CYP4H28v2 and CYP4H31v2 in the mosquito, indicating the potential role of the genes in mediating xenobiotic resistance. This may enhance the survival capabilities of the mosquito when in contact with phytotoxins of leaf litter in their natural ecosystem and synthetic insecticides in adulticide spray regimens.

Background

The use of mosquito coils is a common method of protection against mosquito bites and mosquito borne diseases. These coils are widely marketed and used by households in Malaysia to prevent mosquito associated problems.

Objective

To determine the bioefficacy of commercial d-allethrin and d-trans allethrin spatial repellents against the dengue vector Aedes aegypti.

Method

We evaluated the knockdown and mortality effects of spatial repellents containing d-allethrin (0.3% w/w) and d-trans allethrin (0.1% and 0.15% w/w) on Ae. aegypti in a Peet Grady Chamber, relative to a reference product (0.2% w/w d-allethrin).

Results

The spatial repellent containing 0.3% d-allethrin had the shortest knockdown times (KT₅₀ and KT₉₀) and these were significantly different from the other products including the reference coil except the 0.15% d-trans allethrin coil. The spatial repellent containing 0.3% d-allethrin elicited a mortality response of 96%, which was significantly different from the mortality response to the other coils, except for the 0.15% d-trans allethrin formulation.

Conclusions

Spatial repellents containing 0.3% d-allethrin or 0.15% d-trans allethrin had higher efficacies against Ae. aegypti than repellents containing 0.2% w/w d-allethrin or 0.1% d-trans allethrin and their use by households could offer better relief from Ae. aegypti

Mosquito coils are insecticides commonly used for protection against mosquitoes due to their toxic effects on mosquito populations. These effects on mosquitoes could induce the expression of metabolic enzymes in exposed populations as a counteractive measure. Cytochrome P450 family 4 (CYP4) are metabolic enzymes associated with a wide range of biological activities including insecticide resistance. In this study, the efficacies of three commercial mosquito coils with different pyrethroid active ingredients were assessed and their potential to induce the expression of CYP4 genes in Aedes albopictus analyzed by real-time quantitative PCR. Coils containing 0.3 % d-allethrin and 0.005 % metofluthrin exacted profound toxic effects on Ae. albopictus, inducing high mortalities (≥90 %) compared to the 0.2 % d-allethrin reference coil. CYP4H42 and CYP4H43 expressions were significantly higher in 0.3 % d-allethrin treated mosquitoes compared to the other treated populations. Short-term (KT50) exposure to mosquito coils induced significantly higher expression of both genes in 0.005 % metofluthrin exposed mosquitoes. These results suggest the evaluated products provided better protection than the reference coil; however, they also induced the expression of metabolic genes which could impact negatively on personal protection against mosquito.

Cytochrome P450 is a group of heme-containing enzymes. They have been detected in virtually all organisms examined from bacteria to mammals. In insects, P450s are involved in the oxidative metabolism of a large number of exogenous compounds (xenobiotics) from natural or anthropogenic origins (plant allelochemicals and insecticides) and endogenous compounds such as steroid hormones ecdysteroid hormones and pheromones. Thus the P450s have an important role in controlling insect growth, development, and evolutionary adaptation to environments containing potentially toxic compounds. A novel cDNA clone encoding a cytochrome P450 gene has been isolated from the mosquito, Ae. aegypti strain VCRU. The cDNA is 1731 bp in length and has an open reading frame from 277 bp to 1647 bp encoding a protein of 529 aa. The classic heme-binding characteristic motifs of P450s (FXXGXRXCXG, RxxR and EVLR) are present and conserved in this gene. The EVDTFMFEGHDTT motif characteristic of CYP4 family is also found in this new gene. The full length cDNA clone for CYP4H28v2 is 98% identical to CYP4H28 of The Liverpool strain Ae. aegypti. So, we propose that  this is an allele of that gene.

Cytochrome P450 monooxygenases are versatile biocatalysts that incorporate oxygen into an enormous range of molecules. The cytochrome P450 proteins are involved in the catalysis of different reactions and these properties have been used for drug improvement. The protein family also includes compounds producing properties such as resistance to insecticides, and the synthesis of valuable chemicals. In this review, we will discuss various aspects of the structure and function of the cytochrome P450s