Role of the ApeE Esterase in the Growth of Salmonella on Phospholipids as Phosphate Sources

Salmonella enterica serovar Typhimurium, a bacterium frequently implicated in outbreaks of food poisoning, is able to survive in limiting phosphate environments by inducing a number of proteins that allow it to use a variety of compounds as phosphate sources. The gene apeE is induced when the cells are starved for phosphate. This gene encodes an outer membrane esterase that is not found in E. coli, and has been shown to be necessary for the growth of Salmonella Typhimurium in phosphate-limiting environments, such as those that may be encountered in an egg. To demonstrate the role of apeE in these environments, wild type and apeE mutant strains of Salmonella Typhimurium were separately tested for growth on minimal medium containing either phosphatidylcholine or lisophosphatidycholine as phosphate sources. Growth was observed for the wild type strain in the presence of both phosphate donors, but no growth was observed for the apeE mutant. To further support the role of apeE in the growth of Salmonella Typhimurium under phosphate-limiting conditions, other purified phospholipids as well as egg yolks will be tested for their ability to support the growth of both strains

Patterns of gestational weight gain and its association with birthweight in Nigeria

Background: Despite the increasing global importance of gestational weight gain (GWG) and its impact on birthweight, little is known about the patterns of GWG in African populations.Objectives: To determine the pattern of GWG and its association with birthweight in Nigeria.Methods: It was a longitudinal study of 200 pregnant women receiving antenatal care at two tertiary hospitals in Enugu, south eastern Nigeria. The women were consecutively recruited at <14 weeks gestation and their body mass indexes recorded upon recruitment. Thereafter, weight measurements were taken at each visit until 38–39 weeks.Results: Mean total GWG was 10.7 ± 3.4 kg, while mean birthweight was 3.3 ± 0.6 kg. GWG in second trimester had positive correlation with birthweight (r = 0.164, P = 0.02). Obese women gained above the recommended limits by the "institute of medicine" while underweight women gained below the limits. Excessive total GWG was associated with higher risk of macrosomia [8/21 (38.1%) vs. 7/179; RR: 9.74; 95% CI: 3.9–24.2; P < 0.001] while inadequate total GWG was associated with higher risk of low birth weight [7/72 (9.7%) vs. 3/128 (2.3%; RR: 4.15; 95% CI: 1.1–15.4; P = 0.03]. Maternal age of <35 years, high social class, nulliparity, and regular antenatal care were associated with normal GWG while maternal age <35 years and regular antenatal care were associated with normal birthweight (P < 0.05).Conclusions: Women should be counseled on the factors that influence GWG and birthweight. Interventions to assist women achieve appropriate GWG may need to include components related to improved dietary intake for the underweight and increased physical activity for the obese.Keywords: birthweight, body mass index, pregnancy, Nigeria, weight gai