• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.1-11
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• 2023

The Indian golden muga silkworm, Antheraea assamensis Helfer is an economically important wild silkworm endemic to Northeastern part of India. In recent years, climate change has posed a threat to muga silk production due to the requirement that larvae be reared outdoors. Since the muga silkworm larvae are exposed to the vagaries of nature, the changing climate has increased the incidence of microbial diseases in the rearing fields. Accurate diagnosis of the disease causing pathogens and its associated epidemiology are prerequisites to manage the diseases in the rearing field. Although conventional microbial culturing methods are widely used to identify pathogenic bacteria, they would not provide meaningful information on a wide variety of silkworm pathogens. The information on use of molecular diagnostic tools in detection of microbial pathogens of wild silk moths is very limited. A wide range of molecular and immunodiagnostic techniques including denaturing gradient gel electrophoresis (DGGE), random amplified polymorphism (RAPD), 16S rRNA/ITSA gene sequencing, multiplex polymerase chain reaction (M-PCR), fluorescence in situ hybridization (FISH), immunofluorescence, and repetitive-element PCR (Rep-PCR), have been used for detecting and characterizing the pathogens of insects with economic significance. Nevertheless, the application of these molecular tools for detecting and typing entomopathogens in surveillance studies of muga silkworm rearing is very limited. Here, we discuss the possible application of these molecular techniques, their advantages and major limitations. These methods show promise in better management of diseases in muga ecosystem.

• Research in Plant Disease
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• v.17 no.3
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• pp.369-375
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• 2011

Fusarium verticillioides (teleomorph: Gibberella moniliformis), a member of the Gibberellea fujikuroi species complex, causes rots of corn stalks and ears, and produces a group of mycotoxins known as fumonisins that are harmful to animals and humans. Here, we focus on the development of a species-specific PCR primer set for differentiating F. verticillioides from other fumonisin-producing Fusarium species belonging to the species complex, such as F. proliferatum, F. fujikuroi, and F. subglutinans that are frequently associated with corn. The specific primers (RVERT1 and RVERT2) derived from the nucleotide sequences of RNA polymerase II beta subunit (RPB2) gene amplified a 208 bp-DNA fragment from only F. verticillioides isolates among the potential fumonisin-producing species examined; all of these isolates were shown to carry FUM1 required for fumonisin biosynthesis. The PCR detection limit using this specific primer set was approximately 0.125 pg/${\mu}l$ genomic DNA of F. verticillioides. In addition, the F. verticillioides-specfic fragment was successfully amplified from genomic DNAs of corn samples contaminated with Fusarium spp. This primer set would provide a useful tool for the detection and differentiation of potential fumonisin-producing F. verticillioides strains in cereal samples.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.210-214
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• 2009

This study identified microbial risk factors in agricultural products processing center (APC) through the microbial hazard analysis to introduce good agricultural practices (GAP) system in APCs. Samples were collected from surroundings (basket, tray loader, weighing cup, collector, box) and workers by swabbing (glove and cloth) and glove juice method (hand) to enumerate total bacteria, coliform, Staphylococcus aureus, Escherichia coli, Escherichia coli O157:H7 and Salmonella. The levels of total bacterial and coliform populations recovered from surroundings were 2.4-5.7 log CFU/100 $cm^2$ and 2.3-5.7 log CFU/100 $cm^2$ or hand for surroundings, and workers, respectively samples were 2.3-5.7 log CFU/100 $cm^2$ or hand. Escherichia coli populations were determined to be below detection limit. S. aureus and Salmonella populations recovered from surroundings were 3.0-4.4 log CFU/100 $cm^2$ and close to detection limit, respectively. Corresponding bacterial populations to worker's samples were 2.8-5.2 log CFU/100 $cm^2$ or hand (S. aureus) and below detection limit (Salmonella). Bacterial populations of APC certified facilities were similar (p${\geq}$0.05) with those of uncertified facilities. These results showed that this study should be useful in development of GAP models to improve microbial safety in APCs.

• Journal of Life Science
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• v.26 no.5
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• pp.503-508
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• 2016

Biosensors have been used as first-step monitoring tools to detect on-site samples in a simple and cost-effective manner. Numerous recombinant microbial biosensors have been exploited for monitoring on-site toxic chemicals and biological signals. Herein, a recombinant microbial biosensor was constructed for monitoring cadmium. The cadmium responding cadC regulatory gene and it’s promoter from Staphylococcus aureus was amplified through PCR, fused with the lacZ gene, and transformed into Escherichia coli BL21 (DE3) cells. In the presence of cadmium, the biosensor cells express β-galactosidase showing red color development with chlorophenol red β-galactopyranoside (CPRG) as the enzymatic substrate. The biosensor cells showed the best β-galactosidase activity after 3 hr induction with cadmium at pH 5 and a detection range from 0.01 μM to 10 mM cadmium with a linearity from 0.01 to 0.1 μM cadmium (y = 0.98 x + 0.142, R² = 0.98). Among the heavy metals, cadmium and lead showed good responses, tin and cobalt showed medium responses, and mercury and copper showed no responses. The biosensor cells showed good responses to several waste waters similar to buffer solution, all spiked with cadmium. The biosensor described herein could be applied for on-site cadmium monitoring in a simple and cost-effective manner without sample pretreatments.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.116-124
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• 2008

Statement of the problem: Implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. Purpose: Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans, related to implant-abutment interface microleakage. Material and methods: Samples were taken from 27 subjects with sterilized paper points and were transported in $1{\times}PBS$. The detection of periodontopathogens were performed by polymerase chain reaction with species-specific primers based on 16S rDNA. Results: Our data showed that the detection rate of P. gingivalis and P. intermedia in implant fixture was 59% and 82% in patients respectively. Detection rate of P. gingivalis and P. intermedia in implant crevice was 44% and 82% in patients. Detection rate of P. gingivalis and P. intermedias in tongue was 82% and 82% in patients. Conclusion: Current implant systems cannot safely prevent microbial leakage and bacterial colonization of the inner part of the implant.

• Journal of Microbiology and Biotechnology
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• v.4 no.2
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• pp.85-94
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• 1994

Lipase (triacylglycerol hydrolase, EC 3.1.1.3) is able to catalyze the hydrolysis of ester bonds of triacylglycerols at the interface between aqueous phase and organic phase containing substrate. With the rapid development of lipid biotechnology, lipase-catalyzed hydrolysis of lipids has a great concern from the industrial point of view. Owing to the reversible nature of the lipase, the reactions are also applied for glyceride synthesis, interesterification and resolution of racemic mixtures into optically active alcohols or acids. For all applications of the lipases, a reliable method for the determination of enzyme activity is required. Precise quantitative determination of its activity is essential as the basis of research and development of the bioprocess involving the enzyme. This article reviews the existing literature on the detection and determination of lipase activity from microbial, mammalian and plant sources.

• Journal of Microbiology
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• v.42 no.3
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• pp.216-222
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• 2004

In a previous paper, the ogdH gene that encodes 2-oxoglutarat dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-l and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.71-78
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• 2017

Raman microspectroscopy is a promising tool for microbial analysis at single cell level since it can rapidly measure the cell materials including lipids, nucleic acids, and proteins by measuring the inelastic scattering of a molecule irradiated by monochromatic lights. Using Raman spectra provides high specificity and sensitivity in classification of bacteria at the strain level. In addition, a Raman approach coupled with stabled isotope such as $^{13}C$ and $^2H$ is able to detect and quantify general metabolic activity at single cell level. After bacterial detection process by Raman microspectroscopy, interested unculturable cell sorting and single cell genomics can be accomplished by combination with optical tweezer and microfluidic devices. In this review, the characteristics and applications of Raman microspectroscopy were reviewed and summarized in order to provide a better understanding of microbial analysis using Raman spectroscopy.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.495-510
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• 2022

In this study, fluorescence hyperspectral imaging (FHSI) was used for the rapid, non-destructive detection of fake, manmade eggs from real eggs. To identify fake eggs, protoporphyrin IX (PpIX)-a natural pigment present in real eggshells-was utilized as the main indicator due to its strong fluorescence emission effect. The fluorescence images of real and fake eggs were acquired using a line-scan-based FHSI system, and their fluorescence features were analyzed based on spectroscopic techniques. To improve the detection performance and accuracy, an optimal waveband combination was investigated with analysis of variance (ANOVA), and its fluorescence ratio images (588/645 nm) were created for visualization of the real eggs between two different egg groups. In addition, real and fake eggs were scanned using a one-waveband (645 nm) handheld fluorescence imager that can perform real-time scanning for on-site applications. Then, the results of the two methods were compared with one another. The outcome clearly shows that the newly developed FHSI system and the fluorescence handheld imager were both able to distinguish real eggs from fake eggs. Consequently, FHSI showed a better performance (clearer images) compared to the fluorescence handheld imager, and the outcome provided valuable information about the feasibility of using FHSI imaging with ANOVA for the discrimination of real and fake eggs.

• Journal of Microbiology
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• v.44 no.1
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• pp.72-76
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• 2006

Plasma-derived products are produced from plasma via fractionation and chromatography techniques, but can also be produced by other methods. In the performance of nucleic acid amplification tests (NAT) with plasma-derived products, it is necessary to include an internal control for the monitoring of all procedures. In order to avoid false negative results, we confirmed the usefulness of the bovine viral diarrhoea virus (BVDV) for use as an internal control in the detection of hepatitis C virus (HCV) RNA in plasma-derived products. These products, which were spiked with BVDV, were extracted and then NAT was performed. Specificity and sensitivity were determined via the adjustment of primer concentrations and annealing temperatures. BVDV detection allows for validation in the extraction, reverse transcription, and amplification techniques used for HCV detection in plasma-derived products.