Defluorination of Organofluorine Compounds Using Dehalogenase Enzymes from Delftia acidovorans (D4B).

Organofluorine compounds have been widely used as pharmaceuticals, agricultural pesticides, and water-resistant coatings for decades; however, these compounds are recognized as environmental pollutants. The capability of microorganisms and enzymes to defluorinate organofluorine compounds is both rare and highly desirable to facilitate environmental remediation efforts. Recently, a strain of Delftia acidovorans (D4B) was identified with potential biodegradation activity toward perfluoroalkyl substances (PFAS) and other organofluorine compounds. Genomic analysis found haloacid and fluoroacetate dehalogenases as enzymes associated with Delftia acidovorans. Here, defluorination activity of these enzymes toward different fluorinated substrates was investigated after their recombinant expression and purification from E. coli. Using an electrochemical fluoride probe, 19F NMR, and mass spectrometry to monitor defluorination, we identified two dehalogenases, DeHa2 (a haloacid dehalogenase) and DeHa4 (a fluoroacetate dehalogenase), with activity toward mono- and difluoroacetate. Of the two dehalogenases, DeHa4 demonstrated a low pH optimum compared to DeHa2, which lost catalytic activity under acidic conditions. DeHa2 and DeHa4 are relatively small proteins, operate under aerobic conditions, and remain active for days in the presence of substrates. Significantly, while there have been many reports on dehalogenation of monofluoroacetate by dehalogenases, this study adds to the relatively small list of enzymes reported to carry out enzymatic defluorination of the more recalcitrant disubstituted carbon in an organofluorine compound. Thus, DeHa2 and DeHa4 represent organofluorine dehalogenases that may be used in the future to design and engineer robust defluorination agents for environmental remediation efforts.

Engineering and characterization of dehalogenase enzymes from Delftia acidovorans in bioremediation of perfluorinated compounds.

Per- and Polyfluorinated alkyl substances (PFAS) are a broad class of synthetic compounds that have fluorine substituted for hydrogen in several or all locations and are globally categorized as PFCs (perfluorochemicals; commonly called fluorinated chemicals). These compounds have unique chemical and physical properties that enable their use in non-stick surfaces, fire-fighting efforts, and as slick coatings. However, recent concerns over the health effects of such compounds, specifically perfluorooctanoic acid and perfluorooctane sulfonic acid (PFOA, PFOS; PFOA/S), have led to increased attention and research by the global community into degradation methods. In this study, soil samples from PFAS-contamination sites were cultured and screened for microbes with PFOA/S degradation potential, which led to the identification of Delftia acidovorans. It was found that D. acidovorans isolated from PFAS-contaminated soils was capable of growth in minimal media with PFOA as a sole carbon resource, and an observable fluoride concentration increase was observed when cells were exposed to PFOA. This suggests potential activity of a dehalogenase enzyme that may be of use in PFOA or PFAS microbial remediation efforts. Several associated haloacid dehalogenases have been identified in the D. acidovorans genome and have been engineered for expression in Escherichia coli for rapid production and purification. These enzymes have shown potential for enzymatic defluorination, a significant step in biological degradation and removal of PFOA/S from the environment. We hypothesize that bioremediation of PFAS using naturally occurring microbial degradation pathways may represent a novel approach to remove PFAS contamination.

Experiences from the first 10 years of a perinatal palliative care program: A retrospective chart review.

BACKGROUND: Perinatal palliative care is a relatively new component of paediatric palliative care which supports families who are expecting the birth of a child with a life-limiting condition. This study seeks to understand the characteristics of the infants and families referred for perinatal palliative care and the context for referrals in terms of diagnoses, referral characteristics, interventions, and outcomes. METHODS: A retrospective chart review of infants with prenatally diagnosed life-limiting conditions that were referred for perinatal palliative care. RESULTS: Eighty-five referrals were made for perinatal palliative care during the 10-year period, of which, 84 chose to continue with the service. Average gestational age at diagnosis was 23 weeks, and the mean time between diagnosis and referral to palliative care was 7 weeks. Stillbirths were common, occurring in 29% cases. Of livebirths, 59% of the infants survived for 2 days, and 80% died within 30 days. The most commonly referred conditions were trisomy 13 or 18 (24%), severe central nervous system malformations (20%), and severe congenital cardiac disease (16%). Referrals were most often made by neonatologists (39%), and maternal-fetal medicine specialists (36%). DISCUSSION: Our study confirms previously observed characteristics of diagnosis, referrals, and outcomes, while providing the most detailed account of lifespans for particular diagnoses to date. Our findings validate the need for perinatal palliative care, as 99% of those referred continued with the service. Future research should adopt a prospective approach to identify critical factors affecting decision making of families and physicians in the wake of a life-limiting diagnosis.

The Psychosocial and Spiritual Experiences of Patients with Advanced Incurable Illness in Bangladesh: A Cross-Sectional Observational Study.

CONTEXT: The psychosocial and spiritual needs of individuals with life-limiting conditions in low- or middle-income countries have not been well described. Understanding these needs is important to providing holistic palliative care. AIM: This study aims to better understand the psychosocial and spiritual needs and supports of patients with advanced, incurable illness in Bangladesh. SUBJECTS AND METHODS: Individuals with advanced incurable illnesses (advanced cancer and HIV/AIDS) from a wide geographical distribution across Bangladesh were interviewed about their health status, emotional and spiritual experiences with their illness, coping and support systems, and greatest needs and fears. RESULTS: We interviewed 221 individuals with incurable cancer (82%) or HIV/AIDS (18%). Self-reported health status was poor or very poor for 48%, and 44% reported feeling unhappy all of the time. The majority (61%) rated their current level of unhappiness as 10/10. Spouses (50%), children (15%), and parents (13%) were the most common caregivers. Money and medical care were equally the most common needs (46%). Participants' greatest fears were for the future of their children (38%), being in pain (29%), and dying (28%). CONCLUSIONS: There is a significant burden of psychosocial and spiritual concerns among patients with advanced incurable illness in Bangladesh, with sadness being very frequent and of high intensity. Family and friends provide significant emotional and practical support to patients who are seriously ill, but very few patients access any professional support for these concerns.