Goldberglaugesen0919

The siderophore synthetic system in Shewanella species is able to synthesize dozens of macrocyclic siderophores in vitro with synthetic precursors. In vivo, however, although three siderophores are produced naturally in S. algae B516 which carries a lysine decarboxylase (AvbA) specific for siderophore synthesis, only one siderophore can be detected from many other Shewanella species. In this study, we examined a siderophore-overproducing mutant of S. oneidensis, which lacks an AvbA counterpart, and found that it can also produce these three siderophores. We identified both SpeC and SpeF as promiscuous decarboxylases for both lysine and ornithine to synthesize siderophore precursors cadaverine and putrescine respectively. Intriguingly, putrescine is mainly synthesized from arginine through an arginine decarboxylation pathway in a constitutive manner, not liable to the concentrations of iron and siderophores. Our results provide further evidence that the substrate availability plays a determining role in siderolability. In addition to use the ADC pathway for putrescine synthesis, cells optimize the putrescine pool for siderophore production. Our work provides an insight into coordinated synthesis of multiple siderophores by harnessing promiscuous enzymes in bacteria and underscores the importance of substrate pools for biosynthesis of natural products. Copyright © 2020 American Society for Microbiology.Escherichia coli O157H7 and Salmonella enterica are leading causes of foodborne outbreaks linked to fresh produce. Both species can enter the "viable but non-culturable" (VBNC) state that precludes detection using conventional culture-based or molecular methods. In this study, we assessed propidium monoazide (PMA)-qPCR assays and novel methods combining PMA and loop-mediated isothermal amplification (LAMP) for the detection and quantification of VBNC E. coli O157H7 and S. enterica in fresh produce. The performance of PMA-LAMP assays targeting wzy gene of E. coli O157H7 and agfA gene of S. enterica and PMA-qPCR assays were compared in pure culture and spiked tomato, lettuce and spinach. No cross-reaction was observed in the specificity tests. The limit of detection (LOD) with PMA-LAMP was 9.0 CFU/reaction for E. coli O157H7 and 4.6 CFU/reaction for S. enterica in pure culture, and 5.13×103-4 CFU/g for VBNC E. coli O157H7 and 1.05×104-5 CFU/g for VBNC S. enterica in fresh produce, which was comparable to that oy to determine VBNC E. coli O157H7 and S. enterica in fresh produce, which potentially decreases the risks related to the consumption of fresh produce contaminated by enteric pathogens in this state. PMA-LAMP can be further applied in the field study to enhance our understanding of the fate of VBNC pathogens in the pre- and post-harvest stages of fresh produce. SU11248 Copyright © 2020 American Society for Microbiology.Ergosterol plays an important role in maintaining cell membrane sterol homeostasis in fungi, and as such, is considered as an effective target in antifungal chemotherapy. In yeast, the enzyme acetyl-CoA acetyltransferase (ERG10) catalyzes the Claisen condensation of two acetyl-CoA molecules to acetoacetyl-CoA in the ergosterol biosynthesis pathway and is reported critical for cell viability. Using yeast ERG10 for alignment, two orthologues AfERG10A (AFUB_000550) and AfERG10B (AFUB_083570) were discovered in opportunistic fungal pathogen Aspergillus fumigatus Despite the essentiality of AfERG10B has been previously validated, the biological function of AfERG10A remains unclear. In this study, we have characterized recombinant AfERG10A as a functional acetyl-CoA acetyltransferase catalyzing both synthetic and degradative reactions. Unexpectedly, AfERG10A localizes to mitochondria in A. fumigatus as shown by C-terminal GFP-tag fusion. Both knockout and inducible promoter strategies demonstrate that Aferg10A is eymes are involved in ergosterol biosynthesis of which acetyl-CoA acetyltransferase (ACAT) is the first enzyme. Two ACATs in A. fumigatus are AfErg10A and AfErg10B. However, the biological function of AfErg10A is yet to be investigated. In this study, we showed that AfErg10A is localized in the mitochondria, and is essential for A. fumigatus survival and morphological development. In combination with structural studies we validated AfErg10A as a potential drug target that will facilitate the development of novel antifungals and improve the efficiency of existing drugs. Copyright © 2020 Zhang et al.The clinical goals of intravenous lipid emulsions (ILEs) have changed since their initial development. In the past, 100% soybean oil was used to provide energy and prevent an essential fatty acid deficiency. Now, different oil sources are used with the goal of improving nutritional status and preventing common neonatal comorbidities. We now have a better understanding of specific ILE constituents, namely, fatty acids, vitamin E, and phytosterols, and how these components contribute to complications such as intestinal failure-associated liver disease. This review addresses the development and composition of different ILEs and summarizes how individual ILE ingredients affect infant metabolism and health. Copyright © 2020 by the American Academy of Pediatrics.Assessing and monitoring the physical growth of preterm infants is fundamental to NICU care. The goals of nutritional care are to approximate the growth and body composition of the healthy fetus and to support optimal brain development while minimizing future cardiometabolic risk. Both poor and excessive growth predict adverse long-term health outcomes. Growth curves are clinical tools used to assess the preterm infant's growth status. Several growth curves for preterm infants were developed in the past decade. To use them effectively, clinicians need to understand how each growth curve was developed; the underlying reference population; intended use; and strengths and limitations. Intrauterine growth curves are references that use size at birth to represent healthy fetal growth. These curves serve 2 purposes-to assign size classifications at birth and to monitor postnatal growth. The INTERGROWTH-21 st preterm postnatal growth standards were developed to compare the postnatal growth of preterm infants to that of healthy preterm infants rather than the fetus. Individualized weight growth curves account for the water weight loss that frequently occurs after birth. In addition, body mass index (BMI) curves are now available. In this review, we discuss the main characteristics of growth curves used for preterm infants as well as the use of percentiles, z scores, and their change over time to evaluate size and growth status. We also review the differences in body composition between preterm infants at term-equivalent age and term-born infants and the potential role of monitoring proportionality of growth using BMI curves. Copyright © 2020 by the American Academy of Pediatrics.Hyperglycemia after birth is common in extremely preterm infants ( less then 28 weeks of gestation). Lower gestational age, lower birthweight, presence of severe illness, and higher parenteral glucose intake increase the risk for hyperglycemia, while provision of higher amounts of amino acids and lipids in parenteral nutrition and early initiation and faster achievement of full enteral feeding decrease the risk. Hyperglycemia is associated with increased mortality and morbidity in the neonatal period. link2 Limited data show an association with long-term adverse effects on growth, neurodevelopment, and cardiovascular and metabolic health. Lowering the glucose infusion rate and administration of insulin are the 2 treatment options. Lowering the glucose infusion could lead to calorie deficits and long-term adverse effects on growth and neurodevelopment. Conversely, insulin use increases the risk for hypoglycemia and requires close blood glucose monitoring and frequent adjustments to glucose infusion and insulin dosage. Randomized trials of varying strategies of nutrient provision and/or insulin therapy and long-term follow-up are needed to improve clinical care and overall health of extremely preterm infants with hyperglycemia. Copyright © 2020 by the American Academy of Pediatrics.Prematurity, maternal diabetes, maternal smoking, being medically underserved, and small size for gestational age are common characteristics of neonates in the NICU and can predispose them to develop congenital iron deficiency. Iron is critical for organ development. link3 In the fetus and newborn, iron is prioritized for red blood cell production, sometimes at the expense of other tissues, including the brain. It is critical to optimize iron levels in newborns to support erythropoiesis, growth, and brain development. Available studies support improved neurodevelopmental outcomes with either iron supplementation or delayed umbilical cord clamping at birth. Erythropoietic doses of erythropoietin/erythrocyte-stimulating agents may also improve neurocognitive outcomes. However, the literature on the effect of liberal red blood cell transfusions on long-term neurodevelopment is mixed. Understanding age-specific normal values and monitoring of iron indices can help individualize and optimize the iron status of patients in the NICU. Copyright © 2020 by the American Academy of Pediatrics.The neonatal period from birth to less than or equal to 28 days is one of increased risk of death. Congenital anomalies and prematurity are 2 of the most common risk factors for death at this early age. Many of these neonates will die in an intensive care unit, some with full resuscitative efforts being undertaken despite the understanding that these actions are highly unlikely to yield an outcome different from death. Palliative care allows curative therapies to be provided alongside supportive techniques such as enhanced family communication, attention to spirituality and the psychosocial health of the family, management of symptoms other than those specific to the underlying disease process, and enhancing comfort. The American Academy of Pediatrics has set forth recommendations related to pediatric palliative care for the various pediatric subspecialties; however, much of the focus is on disease processes and curing or mitigating various illnesses. Given the high preponderance of death in the neonatal period, neonatal-perinatal medicine training programs should be tasked with generating formal palliative care training. Such training should be geared to providing better care for neonatal patients with a life-limiting or life-altering illness, and better equipping future neonatologists with the tools needed to provide truly comprehensive care for their sickest patients at risk for death and disability. This article serves to review the concept of palliative care in neonates, discuss the paucity of formal education in palliative care, explore the general trend in palliative care education, review various ways in which palliative care education can be formalized, and define metrics of a successful educational program. Copyright © 2020 by the American Academy of Pediatrics.The principal unmet need in BRAFV600E-positive melanoma is lack of an adequate therapeutic strategy capable of overcoming resistance to clinically approved targeted therapies against oncogenic BRAF and/or the downstream MEK1/2 kinases. We previously discovered that copper (Cu) is required for MEK1 and MEK2 activity through a direct Cu-MEK1/2 interaction. Repurposing the clinical Cu chelator tetrathiomolybdate (TTM) is supported by efficacy in BRAFV600E-driven melanoma models, due in part to inhibition of MEK1/2 kinase activity. However, the antineoplastic activity of Cu chelators is cytostatic. Here, we performed high-throughput small molecule screens to identify bioactive compounds that synergize with TTM in BRAFV600E-driven melanoma cells. Genetic perturbation or pharmacological inhibition of specific members of the BCL2 family of anti-apoptotic proteins (BCL-W, BCL-XL, and MCL-1) selectively reduced cell viability when combined with a Cu chelator and induced CASPASE-dependent cell death. Further, in BRAFV600E-positive melanoma cells evolved to be resistant to BRAF and/or MEK1/2 inhibitors, combined treatment with TTM and the clinically evaluated BCL2 inhibitor, ABT-263, restored tumor growth suppression and induced apoptosis.