Transformation of Lactiplantibacillus plantarum and Apilactobacillus kunkeei is influenced by recipient cell growth temperature, vector replicon, and DNA methylation.

The effects of recipient cell growth temperature, vector choice, and DNA methylation on transformation efficiency were explored for Lactiplantibacillus plantarum strain B38 and Apilactobacillus kunkeei strains YH15 and 3L. All three parameters significantly affected transformation efficiency. L. plantarum B38 and A. kunkeei YH15 transformed at higher efficiencies with the pTW8 vector than with the pTRKH2 vector; conversely, A. kunkeei 3L transformed at higher efficiency with pTRKH2. Mean transformation efficiencies as high as 7.8 × 105 colony forming units (CFU) µg-1 were obtained with pTW8 for B38, as high as 1.2 × 105 CFU µg-1 with pTW8 for YH15, and as high as 3.4 × 106 CFU µg-1 with pTRKH2 for 3L. With respect to methylation, B38 and YH15 transformed at higher efficiencies with DNA that lacked dam methylation, while 3L transformed at higher efficiency with DNA that was dam methylated. Methylation at Escherichia coli dcm sites did not affect the ability of pTRKH2 or pTW8 to transform these strains. Recipient cell growth at 21 °C rather than at 37 °C significantly increased transformation efficiencies when using each strain's preferred vector and methylation state; pTW8 without dam methylation for B38 and YH15 and pTRKH2 with dam methylation for 3L.

Revisiting traumatic injury risk and agricultural intensification: Postcranial fracture frequency at Cerro Oreja in the Moche Valley of north coastal Peru.

OBJECTIVES: In Lambert and Welker (2017) we explored the association between subsistence economy and postcranial fracture prevalence, finding that low-intensity agriculturalists exhibited significantly lower fracture rates than foragers or high-intensity agriculturalists. Here, we explore the impacts of sampling strategy on fracture rates in a sample of high-intensity agriculturalists from the Moche Valley, Peru, and further test the hypothesis that postcranial fracture risks are higher for intensive agriculture. MATERIALS AND METHODS: The long bones and clavicles of 102 individuals from an Early Intermediate Period cemetery (400 B.C.-A.D. 200) at Cerro Oreja were examined for healed fractures. Sample composition was manipulated in six ways to investigate the effects of age and element completeness on estimates of fracture prevalence. Fracture rates at Cerro Oreja were then compared to those for other high-intensity agriculturalists. RESULTS: Both skeletal element completeness and age composition were found to influence fracture rate estimates, reflecting the greater likelihood of identifying healed fractures on better-preserved bones and the accrual of injuries with age. The fracture rate of 3.4% at Cerro Oreja was the median value among seven high-intensity agriculturalist samples. The fracture distribution at Cerro Oreja was most similar to that observed at Kulubnarti, Sudan (Kilgore et al., 1997). DISCUSSION: Skeletal element completeness and age composition can impact fracture rates estimated for skeletal samples and should be considered when conducting comparative analyses. All rates calculated for Cerro Oreja are within the range of those obtained for other high-intensity agriculturalists and support previous findings that traumatic injury risk is higher for high-intensity agriculturalists. Similarities between Cerro Oreja and Kulubnarti suggest that rugged terrain may exacerbate fracture risk for agriculturalists, illustrating the costs of intensive agriculture in suboptimal environments.

Traumatic injury risk and agricultural transitions: A view from the American Southeast and beyond.

OBJECTIVES: Bioarchaeological research has documented a general decline in health with the transition from foraging to farming, primarily with respect to changing patterns of morbidity. Less is known about changes in injury risk, an aspect of health more obviously tied to particular landscapes and behaviors associated with different subsistence regimes. The purpose of this research is to evaluate several hypotheses emerging from the ideal free distribution model (Fretwell & Lucas, ) that predict injury risk based on subsistence-specific practices and land use patterns. MATERIALS AND METHODS: Postcranial fracture frequencies for long bones and clavicles in human skeletal remains from three Southeast U.S. regions permit examination of variability in injury risk among low-intensity (floodplain) farmers. Published data on six hunter-gatherer samples, four low-intensity agriculturalist samples, and six high-intensity agriculturalist samples comprise a comparative sample for examining variability in injury risk across three distinct subsistence traditions. Differences are evaluated using Z scores and the Fisher Exact test, Chi-Square test, and Mann-Whitney U test. RESULTS: While statistically significant differences are apparent among low-intensity farming groups in the Southeast sample, in the global comparison postcranial fractures are significantly less common in low-intensity agriculturalists than in hunter-gatherers or high-intensity agriculturalists. DISCUSSION: The results of this study support the hypothesis that, with respect to traumatic injury risk, low-intensity farming is a risk-averse subsistence strategy in comparison with full-time foraging or high-intensity agriculture. These data suggest that it is not agriculture per se that predicts an increase in this health risk, but rather the mode and intensity of agricultural production, findings that have important ramifications for our understanding of the health consequences of major subsistence transitions.