• Microbiology and Biotechnology Letters
• /
• v.16 no.5
• /
• pp.389-392
• /
• 1988

A clone pSL 2-1, which is a recombinant plasmid believed to contain the mosquitocidal crystal-line protein gene of the Bacillus sphaericus 1593, was expressed in Escherichia coli JM83 and the product of the clone was purified and identified. The unsolubilized mosquitocidal crystal proteins from the B. sphaericus had formed 43, 58, 64, 100, 113, and 130 Kd bands in the SDS-polyacrylamide gel, but the NaOH-solublized proteins at pH 12 formed 2 protein bands of 43- and 64Kd in the gel because the larger protein (precursor) bands were cleaved. The products of the pSL 2-1 clone was purified by Sephadex G-200 and only the fractions having lethal activity to the 3rd in-star larvae of mosquito Culex pipiens were analyzed by the gel. The only single protein band of 42 Kd toxic to the larvae was formed. The major toxic protein being produced from the B. sphaericus 1593 and the pSL 2-1 clone was found to be the 42 Kd.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.11
• /
• pp.1651-1658
• /
• 2020

Since Zika virus (ZIKV) was first detected in Uganda in 1947, serious outbreaks have occurred globally in Yap Island, French Polynesia and Brazil. Even though the number of infections and spread of ZIKV have risen sharply, the pathogenesis and replication mechanisms of ZIKV have not been well studied. ZIKV, a recently highlighted Flavivirus, is a mosquito-borne emerging virus causing microcephaly and the Guillain-Barre syndrome in fetuses and adults, respectively. ZIKV polyprotein consists of three structural proteins named C, prM and E and seven nonstructural proteins named NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5 in an 11-kb single-stranded positive sense RNA genome. The function of individual ZIKV genes on the host innate immune response has barely been studied. In this study, we investigated the modulations of the NF-κB promoter activity induced by the MDA5/RIG-I signaling pathway. According to our results, two nonstructural proteins, NS2A and NS4A, dramatically suppressed the NF-κB promoter activity by inhibiting signaling factors involved in the MDA5/RIG-I signaling pathway. Interestingly, NS2A suppressed all components of MDA5/RIG-I signaling pathway, but NS4A inhibited most signaling molecules, except IKKε and IRF3-5D. In addition, both NS2A and NS4A downregulated MDA5-induced NF-κB promoter activity in a dosedependent manner. Taken together, our results suggest that NS2A and NS4A signifcantly antagonize MDA5/RIG-I-mediated NF-κB production, and these proteins seem to be controlled by different mechanisms. This study could help understand the mechanisms of how ZIKV controls innate immune responses and may also assist in the development of ZIKV-specific therapeutics.

• Genomics & Informatics
• /
• v.14 no.3
• /
• pp.104-111
• /
• 2016

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of -5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of -7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

• BMB Reports
• /
• v.40 no.1
• /
• pp.58-64
• /
• 2007

Similar to the other known structures of Bacillus thuringiensis Cry $\delta$-endotoxins, the crystal structure of the 65-kDa activated Cry4Ba toxin comprises three domains which are, from the N- to C-terminus, a bundle of $\alpha$-helices, a three-$\beta$-sheet domain, and a $\beta$-sandwich. To investigate the properties of the C-terminal domain III in isolation from the rest of the toxin, the cloned Cry4Ba-domain III was over-expressed as a 21-kDa soluble protein in Escherichia coli, which cross-reacted with anti-Cry4Ba domain III monoclonal antibody. A highly-purified domain III was obtained in a monomeric form by ion-exchange and size-exclusion FPLC. Circular dichroism spectroscopy indicated that the isolated domain III fragment distinctly exists as a $\beta$-sheet structure, corresponding to the domain III structure embodied in the Cry4Ba crystal structure. In vitro binding analysis via immuno-histochemical assay revealed that the Cry4Ba-domain III protein was able to bind to the apical microvilli of the susceptible Stegomyia aegypti larval midguts, albeit at lower-binding activity when compared with the full-length active toxin. These results demonstrate for the first time that the C-terminal domain III of the Cry4Ba mosquito-larvicidal protein, which can be isolated as a native folded monomer, conceivably participates in toxin-receptor recognition.

• The Korean Journal of Zoology
• /
• v.36 no.3
• /
• pp.425-432
• /
• 1993

Alkaline phosphatase from Culex pipiens pallens was examined to determine the optimal assay condition and to assay the activity during ovarian development. The activity of alkaline phosphatase in a male and a nongravid female continuously were declined after eclosion. But by the stimulus of a blood meal, the enzyme activity was increased dramatically. At 30 hr. after a blood meal, the maximal activity was reached and then declined. And after 48 hr. after a blood meal, the second activity increase was revealed. This second increase was maintained up to oviposition. The first activity increase was revealed in the midgut and the second increase was done in the ovary to assay the organ distribution of alkaline phosphatase. In electrophresis data, it was shown 5 isozyme bands, ALP-1 and ALP-2 in the ovary, ALP-3 in the thorax and the midgut, and ALP-4 and ALP-5 in the thorax, the fatbody and the midgut in crude extract at 30 hr. after a blood meal. One the same ovary pattern were shown at 72 hr. after a blood meal.

• Journal of Veterinary Clinics
• /
• v.34 no.1
• /
• pp.1-6
• /
• 2017

Heartworm disease (HWD) in dogs is a life-threatening mosquito-borne disease resulting in right-sided congestive heart failure and inflammatory pulmonary disease. Due to complications from adulticidal therapy with melarsomine, slow kill protocol either with preventive dose of ivermectin or combined with doxycycline has been proposed for an alternative adultcidal therapy in dogs with HWD. Therefore, this study evaluated the clinical outcome of adultcidal therapy in dogs with class II stage of HWD after treating either American Heartworm Society (AHS) or slow kill protocol for 10 months. Clinical outcome after therapy was evaluated by clinical, radiographic and echocardiographic examination along with hematology before (D0) and after therapy (D300). Although clinical signs associated with HWD were all resolved after therapy in both groups, the infection was not cleared out 67% of dogs treated by slow kill protocol at the end of therapy. Furthermore, pulmonary arterial flow of acceleration time to ejection time ratio (AT/ET) and the right pulmonary artery distensibility index (RPADI) have been firstly used for detecting pulmonary hypertension in this study group. The pulmonary hypertension was more common in dogs with mild clinical signs, although tricuspid and pulmonary regurgitation were not detectable in most dogs in this study. Our study findings suggested that the slow kill protocol might not be efficacious enough to clear out HWD in dogs and more attention on the presence of pulmonary hypertension might be necessary for effective management of HWD in dogs.

• Parasites, Hosts and Diseases
• /
• v.49 no.3
• /
• pp.313-316
• /
• 2011

Vivax malaria is a significant military and civilian health threat in the north of the Republic of Korea (ROK). The island of Baengnyeong-do is the westernmost point of the ROK and is located close to the southwestern coast of the Democratic People's Republic of Korea (DPRK). Mosquitoes were collected using a black light trap on Baengnyeong-do, and Anopheles spp. were assayed by PCR, to identify the species, and screened for sporozoites of Plasmodium vivax. Of a subsample of 257 mosquitoes, Anopheles lesteri was the most frequently collected (49.8%), followed by Anopheles sinensis (22.6%), Anopheles pullus (18.7%), Anopheles kleini (7.8%), and Anopheles belenrae (1.2%). The overall sporozoite rate was 3.1%, with the highest rates observed in An. kleini (15.0%), An. sinensis (5.2%), and An. lesteri (1.6%). No sporozoite positive An. pullus or An. belenrae were observed. The results extend our knowledge of the distribution and potential role in malaria transmission of An. kleini, An. lesteri, and An. sinensis, for an area previously considered to be at a low risk for contracting vivax malaria.

• Parasites, Hosts and Diseases
• /
• v.56 no.6
• /
• pp.531-543
• /
• 2018

Historically, Plasmodium vivax malaria has been one of the most highly endemic parasitic diseases in the Korean Peninsula. Until the 1970s, vivax malaria was rarely directly lethal and was controlled through the Korean Government Program administered by the National Malaria Eradication Service in association with the World Health Organization's Global Malaria Eradication Program. Vivax malaria has re-emerged in 1993 near the Demilitarized Zone between South and North Korea and has since become an endemic infectious disease that now poses a serious public health threat through local transmission in the Republic of Korea. This review presents major lessons learned from past and current malaria research, including epidemiological and biological characteristics of the re-emergent disease, and considers some interesting patterns of diversity. Among other features, this review highlights temporal changes in the genetic makeup of the parasitic population, patient demographic features, and spatial distribution of cases, which all provide insight into the factors contributing to local transmission. The data indicate that vivax malaria in Korea is not expanding exponentially. However, continued surveillance is needed to prevent future resurgence.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.12
• /
• pp.1801-1809
• /
• 2020

Chikungunya virus (CHIKV) was first identified in 1952 as a causative agent of outbreaks. CHIKV is transmitted by two mosquito species, Aedes aegypti and A. albopictus. Symptoms after CHIKV infection in human are typically fever and joint pain, but can also include headache, muscle pain, joint swelling, polyarthralgia, and rash. CHIKV is an enveloped single-stranded, positive-sense RNA virus with a diameter of approximately 70 nm. The pathogenesis of CHIKV infection and the mechanism by which the virus evades the innate immune system remain poorly understood. Moreover, little is known about the roles of CHIKV-encoded genes in the viral evasion of host immune responses, especially type I interferon (IFN) responses. Therefore, in the present study, we screened CHIKV-encoded genes for their regulatory effect on the activation of nuclear factor kappa B (NF-κB), a critical transcription factor for the optimal activation of IFN-β. Among others, non-structural protein 2 (nsP2) strongly inhibited melanoma differentiation-associated protein 5 (MDA5)-mediated induction of the NF-κB pathway in a dose-dependent manner. Elucidation of the detailed mechanisms of nsP2-mediated inhibition of the MDA5/RIG-I signaling pathway is anticipated to contribute to the development of virus-specific therapeutics against CHIKV infection.

• BMB Reports
• /
• v.55 no.11
• /
• pp.571-576
• /
• 2022

Advancements in the field of proteomics have provided opportunities to develop diagnostic and therapeutic strategies against various diseases. About half of the world's population remains at risk of malaria. Caused by protozoan parasites of the genus Plasmodium, malaria is one of the oldest and largest risk factors responsible for the global burden of infectious diseases with an estimated 3.2 billion persons at risk of infection. For epidemiological surveillance and appropriate treatment of individuals infected with Plasmodium spp., timely detection is critical. In this study, we used combinations of depletion of abundant plasma proteins, 2-dimensional gel electrophoresis (2-DE), image analysis, LC-MS/MS and western blot analysis on the plasma of healthy donors (100 individuals) and vivax and falciparum malaria patients (100 vivax malaria patients and 8 falciparum malaria patients). These analyses revealed that α1-antichymotrypsin (AACT) protein levels were elevated in vivax malaria patient plasma samples (mean fold-change ± standard error: 2.83 ± 0.11, based on band intensities), but not in plasma from patients with other mosquito-borne infectious diseases. The results of AACT immunoblot analyses showed that AACT protein was significantly elevated in vivax and falciparum malaria patient plasma samples (≥ 2-fold) compared to healthy control donor plasma samples, which has not been previously reported.