Kyung-Don Kang

6.9 – Genetically Modified Baculoviruses for Pest Insect Control

Abstract Baculoviruses are insect pathogenic viruses that are used for pest insect control and as tools to produce recombinant proteins. Numerous studies show that both natural baculoviruses and genetically modified (GM) baculoviruses hold clear and substantial benefits for crop protection. Natural baculoviruses and potentially GM baculoviruses are particularly valuable under conditions where traditional chemical insecticides, have become ineffective, are economically prohibitive or have lost favor with the general public. The increased use of natural baculoviruses for pest insect control as well as GM baculoviruses for the production of pharmaceuticals may open doors to the use of GM baculoviruses for pest insect control. We review here the major approaches that are used to modify the baculovirus genome for improved efficacy as a biopesticide. The most common and successful of these approaches involve the insertion of a gene into the baculovirus genome that disrupts host insect feeding or is toxic to the host. GM baculoviruses remain a viable alternative to synthetic chemical pesticides and GM crops, we believe that baculoviruses should be utilized when alternative methods of pest insect control are required due to resistance, high cost of traditional insecticides, or changes in the regulatory environment and public opinion.

Assessment of antidiabetogenic potential of fermented soybean extracts in streptozotocin-induced diabetic rat

Most of the available drugs for the treatment of diabetes mellitus (DM) produce detrimental side effects, which has prompted an ongoing search for plant with the antidiabetic potential. The present study investigated the effect of soybean extracts fermented with Bacillus subtilis MORI, fermented soybean extracts (BTD-1) was investigated in streptozotocin (STZ)-induced diabetic rats. The possible effects of BTD-1 against hyperglycemia and free radical-mediated oxidative stress was investigated by assaying the plasma glucose level and the activity of enzymatic antioxidants, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA). A significant increase in the levels of both plasma glucose and reactive oxygen species (ROS) was observed in the diabetic rats when compared to normal control group. After administration of BTD-1 (500 and 1000 mg/kg/day), the elevated plasma glucose level was significantly reduced while the plasma insulin level and the activities of SOD, GSH-Px, CAT and MDA were significantly increased. The results suggest that administration of BTD-1 can inhibit hyperglycemia and free radical-mediated oxidative stress. The administration of BTD-1 also inhibited the contractile response by norepinephrine (10(-10)-10(-5) M) in the presence of endothelium, and caused significant relaxation by carbachol (10(-8)-10(-5) M) in rat aorta. These findings indicate that BTD-1 improves vascular functions on STZ-induced diabetic rats. Therefore, subchronic administration of BTD-1 could prevent the functional changes in vascular reactivity in STZ-induced diabetic rats. The collective findings support that administration of BTD-1 may prevent some diabetes-related changes in vascular reactivity directly and/or indirectly due to its hypoglycaemic effect and inhibition of production of ROS.

Anti-hyperlipidemic effect of soybean extract fermented by Bacillus subtilis MORI in db/db mice

The purpose of this study was to investigate the anti-hyperlipidemic effect of soy bean extract solution fermented by Bacillus subtilis MORI (BTD-1E) in obese db/db mice. Eight-week-old male db/db mice were administered 33.3 mg/kg BTD-1E solution orally once a day for four weeks. The BTD-1E group showed significantly lower body weight compared with the db control group (P<0.05). The BTD-1E group showed significantly lower serum total cholesterol and LDL cholesterol levels compared with the db control group, respectively (P<0.05, P<0.01). The BTD-1E group showed significantly decreased liver weight relative to final body weight compared with the db control group (P<0.01). After four weeks of BTD-1E administration, lipid droplets in the liver were apparently decreased in the BTD-1E group compared to the db control group. In summary, our results suggest that BTD-1E has an anti-hyperlipidemic effect in the obese mouse model.

Effect of starvation upon baculovirus replication in larval Bombyx mori and Heliothis virescens.

The progression of baculovirus (BmNPV, BmCysPD, AcMNPV or AcAaIT) infection in larval Bombyx mori and Heliothis virescens (1st, 3rd or 5th instar) was investigated following various starvation regimes. When the larvae were starved for 12 or 24h immediately following inoculation, the median lethal time to death (LT(50)) was delayed by 9.5-19.2h in comparison to non-starved controls. This corresponded to a delay of 10-23% depending upon the larval stage and virus that was used for inoculation. When a 24h-long starvation period was initiated at 1 or 2 days post inoculation (p.i.), a statistically significant difference in LT(50) was not found indicating that the early stages of infection are more sensitive to the effects of starvation. Viral titers in the hemolymph of 5th instar B. mori that were starved for 24h immediately following inoculation were 10-fold lower (p<0.01) than that found in non-starved control larvae. Histochemical analyses indicated that virus transmission was reduced in 5th instar B. mori that were starved for 24h immediately following inoculation in comparison to non-starved control larvae. In general, the mass of larvae that were starved immediately after inoculation was 30% lower than that of non-starved control insects. Our findings indicate that starvation of the larval host at the time of baculovirus exposure has a negative effect on the rate baculovirus transmission and pathogenesis.

Organic Acid Profiling Analysis in Culture Media of Lactic Acid Bacteria by Gas Chromatography-Mass Spectrometry

Organic acid (OA) profiling analysis was performed in culture media from Lactobacillus pentosus K34 (L. pentosus K34) and Pediococcus lolli PL24 (P. lolli PL24) by gas chromatography-mass spectrometry (GC-MS) following methoxime/ tert-butyldimethylsilyl derivatives. 12 OAs were positively identified in culture media. Most of OA levels from L. pentosus K34 of hetero lactic fermentation were found to be higher when compared with those from P. lolli PL24 of homo lactic fermentation, which may explain different OA metabolism in each strain. In addition, the distorted dodecagonal star patterns were readily dis- tinguishable, and the characteristics of each strain were well represented. The present study demonstrates that the OA metabolic profiling method by GC-MS combined with star pattern recognition is useful for the monitoring study of characteristic OA metabolism in various microorganisms.