The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species.
Invasive meningococcal disease (IMD) imposes a significant burden on the global community due to its high case fatality rate (4-20%) and the risk of long-term sequelae for one in five survivors. An expert group meeting was held to discuss the epidemiology of IMD and immunization policies in Malaysia, Philippines, Thailand, and Vietnam. Most of these countries do not include meningococcal immunization in their routine vaccination programs, except for high-risk groups such as immunocompromised people and pilgrims. It is difficult to estimate the epidemiology of IMD in the highly diverse Asia-Pacific region, but available evidence indicate serogroup B is increasingly dominant. Disease surveillance systems differ by country. IMD is not a notifiable disease in some of them. Without an adequate surveillance system in the region, the risk and the burden of IMD might well be underestimated. With the availability of new combined meningococcal vaccines and the World Health Organization roadmap to defeat bacterial meningitis by 2030, a better understanding of the epidemiology of IMD in the Asia-Pacific region is needed.