Effect of Staphylococcus aureus Infection on Biochemical and Antioxidant Activities of Fifth Instar Silkworm Larvae (Bombyx mori L.)

Harinatha Reddy A

doi:10.4172/2155-9597.1000286

Abstract

In the present study silkworm used as a model animal for evaluating the pathogenicity of Staphylococcus aureus. The fifth instar silkworm larvae was used and infected by intrahaemocoelic injection of bacterial sample. The haemolymph was collected from the infected and control group larvae at 6, 12, 18 and 24 hours of post infection and stored at -4°C in eppendorf tubes to use. Lipid peroxidation, phenol oxidase and acid phosphatase activity were estimated in the haemolymph of control and infected group. This indicated that there was a gradual increase in lipid peroxidation, phenol oxidase and acid phosphatase activities in infected group when compared with control group. The antioxidant enzyme activities were estimated in the haemolymph of control and infected group. We found that the antioxidant enzyme activities were decreased after 24 hours of infection with S. aureus. The silk glands were removed and the wet weight was measured, the wet weight of the silk glands was decreased on the 24 hours of infection when compared with control group.

Highlights

Silkworm is a domesticated and economically important insect, being a primary producer of silk
Microorganisms that are pathogenic to humans, such as Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, have lethal effects in silkworms when injected into the haemolymph [2,3,4,5]
Lipid peroxidation (LPO) assay The malondialdehyde (MDA) concentration was increased in the haemolymph of silkworm larvae infected with S. aureus when compared with control group

Summary

Introduction

Silkworm is a domesticated and economically important insect, being a primary producer of silk. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital acquired infections that are becoming increasingly difficult to combat because of emerging resistance to all current antibiotic classes [6]. These strains appear to contain particular factors or genetic backgrounds that enhance their virulence [7]. S. aureus produces a wide variety of exotoxins that contribute to its ability to colonize and cause disease in mammalian hosts. This includes four hemolysins (alpha, beta, gamma, and delta), nucleases, proteases, lipases, hyaluronidase and collagenase. Toxic shock syndrome toxin (TSST) is the super antigen of the S

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Discussion

Conclusion