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Fulltext Characterization on malathion and permethrin resistance by bioassays and the variation of esterase activity with the life stages of the mosquito Culex quinquefasciatus

Selvi S, Edah MA, Nazni WA, Lee HL, Azahari AH

Trop Biomed, 2007 Jun;24(1):63-75.
PMID: 17568379 MyJurnal

Larvae and adults of Culex quinquefasciatus were used for the test undertaken for malathion resistant strain (F61 - F65) and permethrin resistant strain (F54 - F58). The results showed that the LC50 for both malathion (F61 - F65) and permethrin (F54 - F58) resistant Cx. quinquefasciatus increased steadily throughout the subsequent five generations, indicating a marked development of resistance. The adult female malathion resistant strain have developed a high resistance level to malathion diagnostic dosage with a resistance ratio of 9.3 to 17.9 folds of resistance compared with the susceptible Cx. quinquefasciatus. Permethrin resistance ratio remained as 1.0 folds of resistance at every generation. It was obvious that malathion resistance developed at a higher rate in adult females compared to permethrin. Enzyme-based metabolic mechanisms of insecticide resistance were investigated based on the biochemical assay principle. From the results obtained obviously shows that there is a significant difference (p < 0.05) in esterase level in both malathion and permethrin selected strains. Female malathion selected strain has the higher level of esterase activity compared to the female permethrin selected strain at (0.8 to 1.04) alpha-Na micromol/min/mg protein versus (0.15 to 0.24) alpha-Na micromol/min/mg protein respectively. This indicated increased level of non-specific esterase is playing an important role in resistance mechanism in female malathion selected strain. Permethrin selected strain exhibited non-specific esterase activity at a very low level throughout the different life stages compared to malathion selected strain. This study suggests that life stages play a predominant role in conferring malathion and permethrin resistance in Cx. quinquefasciatus.

Matched MeSH terms: Life Cycle Stages
Fulltext Evaluation of reference genes at different developmental stages for quantitative real-time PCR in Aedes aegypti

Dzaki N, Ramli KN, Azlan A, Ishak IH, Azzam G

Sci Rep, 2017 03 16;7:43618.
PMID: 28300076 DOI: 10.1038/srep43618

The mosquito Aedes aegypti (Ae. aegypti) is the most notorious vector of illness-causing viruses such as Dengue, Chikugunya, and Zika. Although numerous genetic expression studies utilizing quantitative real-time PCR (qPCR) have been conducted with regards to Ae. aegypti, a panel of genes to be used suitably as references for the purpose of expression-level normalization within this epidemiologically important insect is presently lacking. Here, the usability of seven widely-utilized reference genes i.e. actin (ACT), eukaryotic elongation factor 1 alpha (eEF1α), alpha tubulin (α-tubulin), ribosomal proteins L8, L32 and S17 (RPL8, RPL32 and RPS17), and glyceraldeyde 3-phosphate dehydrogenase (GAPDH) were investigated. Expression patterns of the reference genes were observed in sixteen pre-determined developmental stages and in cell culture. Gene stability was inferred from qPCR data through three freely available algorithms i.e. BestKeeper, geNorm, and NormFinder. The consensus rankings generated from stability values provided by these programs suggest a combination of at least two genes for normalization. ACT and RPS17 are the most dependably expressed reference genes and therefore, we propose an ACT/RPS17 combination for normalization in all Ae. aegypti derived samples. GAPDH performed least desirably, and is thus not a recommended reference gene. This study emphasizes the importance of validating reference genes in Ae. aegypti for qPCR based research.

Matched MeSH terms: Life Cycle Stages
Fulltext Assessment of Aedes albopictus reference genes for quantitative PCR at different stages of development

Dzaki N, Azzam G

PLoS One, 2018;13(3):e0194664.
PMID: 29554153 DOI: 10.1371/journal.pone.0194664

Members of the Aedes genus of mosquitoes are widely recognized as vectors of viral diseases. Ae.albopictus is its most invasive species, and are known to carry viruses such as Dengue, Chikugunya and Zika. Its emerging importance puts Ae.albopictus on the forefront of genetic interaction and evolution studies. However, a panel of suitable reference genes specific for this insect is as of now undescribed. Nine reference genes, namely ACT, eEF1-γ, eIF2α, PP2A, RPL32, RPS17, PGK1, ILK and STK were evaluated. Expression patterns of the candidate reference genes were observed in a total of seventeen sample types, separated by stage of development and age. Gene stability was inferred from obtained quantification data through three widely cited evaluation algorithms i.e. BestKeeper, geNorm, and NormFinder. No single gene showed a satisfactory degree of stability throughout all developmental stages. Therefore, we propose combinations of PGK and ILK for early embryos; RPL32 and RPS17 for late embryos, all four larval instars, and pupae samples; eEF1-γ with STK for adult males; eEF1-γ with RPS17 for non-blood fed females; and eEF1-γ with eIF2α for both blood-fed females and cell culture. The results from this study should be able to provide a more informed selection of normalizing genes during qPCR in Ae.albopictus.

Matched MeSH terms: Life Cycle Stages/genetics*
Fulltext Effect of selected local medicinal plants on the asexual blood stage of chloroquine resistant Plasmodium falciparum

Mohd Abd Razak MR, Afzan A, Ali R, Amir Jalaluddin NF, Wasiman MI, Shiekh Zahari SH, et al.

BMC Complement Altern Med, 2014;14:492.
PMID: 25510573 DOI: 10.1186/1472-6882-14-492

The development of resistant to current antimalarial drugs is a major challenge in achieving malaria elimination status in many countries. Therefore there is a need for new antimalarial drugs. Medicinal plants have always been the major source for the search of new antimalarial drugs. The aim of this study was to screen selected Malaysian medicinal plants for their antiplasmodial properties.

Matched MeSH terms: Life Cycle Stages
Fulltext Plasmacytoid dendritic cells appear inactive during sub-microscopic Plasmodium falciparum blood-stage infection, yet retain their ability to respond to TLR stimulation

Loughland JR, Minigo G, Sarovich DS, Field M, Tipping PE, Montes de Oca M, et al.

Sci Rep, 2017 06 01;7(1):2596.
PMID: 28572564 DOI: 10.1038/s41598-017-02096-2

Plasmacytoid dendritic cells (pDC) are activators of innate and adaptive immune responses that express HLA-DR, toll-like receptor (TLR) 7, TLR9 and produce type I interferons. The role of human pDC in malaria remains poorly characterised. pDC activation and cytokine production were assessed in 59 malaria-naive volunteers during experimental infection with 150 or 1,800 P. falciparum-parasitized red blood cells. Using RNA sequencing, longitudinal changes in pDC gene expression were examined in five adults before and at peak-infection. pDC responsiveness to TLR7 and TLR9 stimulation was assessed in-vitro. Circulating pDC remained transcriptionally stable with gene expression altered for 8 genes (FDR

Matched MeSH terms: Life Cycle Stages
In vivo study of human Plasmodium knowlesi in Macaca fascicularis

Anderios F, Noorrain A, Vythilingam I

Exp Parasitol, 2010 Feb;124(2):181-9.
PMID: 19765587 DOI: 10.1016/j.exppara.2009.09.009

Plasmodium knowlesi is a malaria parasite of Old World monkeys and is infectious to humans. In this study Macaca fascicularis was used as a model to understand the host response to P. knowlesi using parasitological and haematological parameters. Three M. fascicularis of either sex were experimentally infected with P. knowlesi erythrocytic parasites from humans. The pre-patent period for P. knowlesi infection in M. fascicularis ranged from seven to 14 days. The parasitemia observed was 13,686-24,202 parasites per microL of blood for asexual stage and 88-264 parasites per microL of blood for sexual stage. Periodicity analysis adopted from microfilaria periodicity technique of asexual stage showed that the parasitemia peak at 17:39h while the sexual stage peaked at 02:36 h. Mathematical analysis of the data indicates that P. knowlesi gametocytes tend to display periodicity with a peak (24:00-06:00) that coincides with the peak biting activity (19:00-06:00) of the local vector, Anopheles latens. The morphology of P. knowlesi resembled P. falciparum in early trophozoite and P. malariae in late trophozoite. However, it may be distinguishable by observing the appliqué appearance of the cytoplasm and the chromatin lying inside the ring. Haematological analysis on macaques with knowlesi malaria showed clinical manifestations of hypoglycaemia, anaemia and hyperbilirubinemia. Gross examination of spleen and liver showed malaria pigments deposition in both organs.

Matched MeSH terms: Life Cycle Stages
Newcastle disease virus Malaysian strain AF2240 induces apoptosis in MCF-7 human breast carcinoma cells at an early stage of the virus life cycle

Ghrici M, El Zowalaty M, Omar AR, Ideris A

Int J Mol Med, 2013 Mar;31(3):525-32.
PMID: 23337979 DOI: 10.3892/ijmm.2013.1244

Newcastle disease virus (NDV) AF2240 Malaysian strain is a very virulent avian virus. NDV strain AF2240 was previously demonstrated to induce apoptosis in human breast carcinoma MCF-7 cells. However, at which stage of the NDV life cycle apoptosis is induced and whether NDV replication and protein synthesis are involved in apoptosis induction have yet to be determined. In the present study, we investigated the time course of NDV strain AF2240 nucleoprotein (NP) gene expression and the early apoptotic signs in the form of activation of caspase-8 and mitochondrial transition pore opening. In addition, the induction of apoptosis by both ultraviolet-inactivated and cycloheximide-treated NDV-infected MCF-7 cells were examined. Our findings showed that NDV strain AF2240 induced apoptosis at 1 h post-infection (pi) through activation of mitochondrial transition pore opening and at 2 h through activation of caspase-8, while the NP gene was expressed at 6 h pi. The induced apoptosis was independent of both virus replication and protein synthesis. In conclusion, NDV strain AF2240 induces apoptosis at an early stage of its life cycle, possibly during virus binding or fusion with the cell membrane. The mitochondrial-related pathway may be the central activator in NDV strain AF2240-induced apoptosis.

Matched MeSH terms: Life Cycle Stages
Fulltext Natural Flavonoids as Potential Angiotensin-Converting Enzyme 2 Inhibitors for Anti-SARS-CoV-2

Muchtaridi M, Fauzi M, Khairul Ikram NK, Mohd Gazzali A, Wahab HA

Molecules, 2020 Sep 01;25(17).
PMID: 32882868 DOI: 10.3390/molecules25173980

Over the years, coronaviruses (CoV) have posed a severe public health threat, causing an increase in mortality and morbidity rates throughout the world. The recent outbreak of a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the current Coronavirus Disease 2019 (COVID-19) pandemic that affected more than 215 countries with over 23 million cases and 800,000 deaths as of today. The situation is critical, especially with the absence of specific medicines or vaccines; hence, efforts toward the development of anti-COVID-19 medicines are being intensively undertaken. One of the potential therapeutic targets of anti-COVID-19 drugs is the angiotensin-converting enzyme 2 (ACE2). ACE2 was identified as a key functional receptor for CoV associated with COVID-19. ACE2, which is located on the surface of the host cells, binds effectively to the spike protein of CoV, thus enabling the virus to infect the epithelial cells of the host. Previous studies showed that certain flavonoids exhibit angiotensin-converting enzyme inhibition activity, which plays a crucial role in the regulation of arterial blood pressure. Thus, it is being postulated that these flavonoids might also interact with ACE2. This postulation might be of interest because these compounds also show antiviral activity in vitro. This article summarizes the natural flavonoids with potential efficacy against COVID-19 through ACE2 receptor inhibition.

Matched MeSH terms: Life Cycle Stages
Fulltext A clinical tool to predict Plasmodium vivax recurrence in Malaysia

Mat Ariffin N, Islahudin F, Kumolosasi E, Makmor-Bakry M

BMC Infect Dis, 2017 12 08;17(1):759.
PMID: 29216842 DOI: 10.1186/s12879-017-2868-9

BACKGROUND: Recurrence rates of Plasmodium vivax infections differ across various geographic regions. Interestingly, South-East Asia and the Asia-Pacific region are documented to exhibit the most frequent recurrence incidences. Identifying patients at a higher risk for recurrences gives valuable information in strengthening the efforts to control P. vivax infections. The aim of the study was to develop a tool to identify P. vivax- infected patients that are at a higher risk of recurrence in Malaysia.
METHODS: Patient data was obtained retrospectively through the Ministry of Health, Malaysia, from 2011 to 2016. Patients with incomplete data were excluded. A total of 2044 clinical P. vivax malaria cases treated with primaquine were included. Data collected were patient, disease, and treatment characteristics. Two-thirds of the cases (n = 1362) were used to develop a clinical risk score, while the remaining third (n = 682) was used for validation.
RESULTS: Using multivariate analysis, age (p = 0.03), gametocyte sexual count (p = 0.04), indigenous transmission (p = 0.04), type of treatment (p = 0.12), and incomplete primaquine treatment (p = 0.14) were found to be predictors of recurrence after controlling for other confounding factors; these predictors were then used in developing the final model. The beta-coefficient values were used to develop a clinical scoring tool to predict possible recurrence. The total scores ranged between 0 and 8. A higher score indicated a higher risk for recurrence (odds ratio [OR]: 1.971; 95% confidence interval [CI]: 1.562-2.487; p ≤ 0.001). The area under the receiver operating characteristic (ROC) curve of the developed (n = 1362) and validated model (n = 682) was of good accuracy (ROC: 0.728, 95% CI: 0.670-0.785, p value

Matched MeSH terms: Life Cycle Stages