RESUMEN
Intrauterine growth restriction leads to an altered lipid and amino acid profile in the cord blood at the end of pregnancy. Pre-pregnancy underweight is an early risk factor for impaired fetal growth. The aim of this study was to investigate whether a pre-pregnancy body mass index (ppBMI) of <18.5 kg/m2, as early as at the beginning of pregnancy, is associated with changes in the umbilical cord metabolome. In a sample of the Survey of Neonates in Pomerania (SNIP) birth cohort, the cord blood metabolome of n = 240 newborns of mothers with a ppBMI of <18.5 kg/m2 with n = 208 controls (ppBMI of 18.5-24.9 kg/m2) was measured by NMR spectrometry. A maternal ppBMI of <18.5 kg/m2 was associated with increased concentrations of HDL4 cholesterol, HDL4 phospholipids, VLDL5 cholesterol, HDL 2, and HDL4 Apo-A1, as well as decreased VLDL triglycerides and HDL2 free cholesterol. A ppBMI of <18.5 kg/m2 combined with poor intrauterine growth (a gestational weight gain (GWG) < 25th percentile) was associated with decreased concentrations of total cholesterol; cholesterol transporting lipoproteins (LDL4, LDL6, LDL free cholesterol, and HDL2 free cholesterol); LDL4 Apo-B; total Apo-A2; and HDL3 Apo-A2. In conclusion, maternal underweight at the beginning of pregnancy already results in metabolic changes in the lipid profile in the cord blood, but the pattern changes when poor GWG is followed by pre-pregnancy underweight.
Asunto(s)
Índice de Masa Corporal , Sangre Fetal , Metaboloma , Delgadez , Humanos , Sangre Fetal/metabolismo , Sangre Fetal/química , Femenino , Embarazo , Recién Nacido , Delgadez/sangre , Adulto , Retardo del Crecimiento Fetal/sangre , MasculinoRESUMEN
PURPOSE: Despite the need to generate valid and reliable estimates of protection levels against SARS-CoV-2 infection and severe course of COVID-19 for the German population in summer 2022, there was a lack of systematically collected population-based data allowing for the assessment of the protection level in real time. METHODS: In the IMMUNEBRIDGE project, we harmonised data and biosamples for nine population-/hospital-based studies (total number of participants n = 33,637) to provide estimates for protection levels against SARS-CoV-2 infection and severe COVID-19 between June and November 2022. Based on evidence synthesis, we formed a combined endpoint of protection levels based on the number of self-reported infections/vaccinations in combination with nucleocapsid/spike antibody responses ("confirmed exposures"). Four confirmed exposures represented the highest protection level, and no exposure represented the lowest. RESULTS: Most participants were seropositive against the spike antigen; 37% of the participants ≥ 79 years had less than four confirmed exposures (highest level of protection) and 5% less than three. In the subgroup of participants with comorbidities, 46-56% had less than four confirmed exposures. We found major heterogeneity across federal states, with 4-28% of participants having less than three confirmed exposures. CONCLUSION: Using serological analyses, literature synthesis and infection dynamics during the survey period, we observed moderate to high levels of protection against severe COVID-19, whereas the protection against SARS-CoV-2 infection was low across all age groups. We found relevant protection gaps in the oldest age group and amongst individuals with comorbidities, indicating a need for additional protective measures in these groups.
Asunto(s)
COVID-19 , Humanos , Estaciones del Año , COVID-19/epidemiología , SARS-CoV-2 , Alemania/epidemiología , Pueblo Europeo , Anticuerpos AntiviralesRESUMEN
Biobanks are important infrastructures facilitating biomedical research. After a decade of rolling out such infrastructures, a shift in attention to the sustainability of biobanks could be observed in recent years. In this regard, an increase in the as yet relatively low utilisation rates of biobanks has been formulated as a goal. Higher utilisation rates can only be achieved if the perspectives of potential users of biobanks-particularly researchers not yet collaborating with biobanks-are adequately considered. To better understand their perspectives, a survey was conducted at ten different research institutions in Germany hosting a centralised biobank. The survey targeted potential users of biobank services, i.e. researchers working with biosamples. It addressed the general demand for biosamples, strategies for biosample acquisition/storage and reasons for/against collaborating with biobanks. In total, 354 researchers filled out the survey. Most interestingly, only a minority of researchers (12%) acquired their biosamples via biobanks. Of the respondents not collaborating with biobanks on sample acquisition, around half were not aware of the (services of the) respective local biobank. Those who actively decided against acquiring biosamples via a biobank provided different reasons. Most commonly, respondents stated that the biosamples required were not available, the costs were too high and information about the available biosamples was not readily accessible. Biobanks can draw many lessons from the results of the survey. Particularly, external communication and outreach should be improved. Additionally, biobanks might have to reassess whether their particular collection strategies are adequately aligned with local researchers' needs.
Asunto(s)
Bancos de Muestras Biológicas , Investigación Biomédica , Humanos , Participación de los Interesados , Alemania , Encuestas y CuestionariosRESUMEN
Maternal thyroid hormones facilitate optimal foetal neurodevelopment; however, the exact role of the thyroid hormones on specific cognitive outcomes is unknown. The present study aimed to investigate associations between maternal thyroid function and neurodevelopmental outcomes in the Seychelles Child Development Study (SCDS) Nutrition 2 cohort (n 1328). Maternal free thyroid hormones (fT3, fT4 and fTSH) were assessed at 28 weeks' gestation with a range of child cognitive outcomes analysed at 20 months. Dietary iodine intake was analysed for a subset of women through a Food Frequency Questionnaire. Linear regression analysis was used to test associations between serum concentrations of maternal thyroid hormones and child neurodevelopment outcomes. Thyroid hormones were analysed as continuous data and categorised as quintiles. 95% of mothers had optimal thyroid function based on fTSH concentrations. Overall, the present study shows that maternal thyroid function is not associated with neurodevelopmental outcomes in this high fish-eating population. However, a positive association, using quintiles for fT3, was reported for the Mental Developmental Index, between Q3 v. Q4 (ß 0â 073; P 0â 043) and for Q3 v. Q5 (ß value 0â 086; P 0â 018). To conclude, mothers in our cohort, who largely have optimal thyroid function and iodine intakes, appear able to regulate thyroid function throughout pregnancy to meet neurodevelopmental needs. However, it is possible that minor imbalances of fT3, as indicated from our secondary analysis, may impact offspring neurodevelopment. Further investigation of the relationship between maternal thyroid function and infant neurodevelopment is warranted, particularly in populations with different dietary patterns and thereby iodine intakes.
Asunto(s)
Desarrollo Infantil , Sistema Nervioso/crecimiento & desarrollo , Glándula Tiroides , Femenino , Humanos , Lactante , Yodo/administración & dosificación , Madres , Embarazo , Seychelles , Glándula Tiroides/fisiología , Hormonas Tiroideas/sangreRESUMEN
BACKGROUND: Long patient transport times to trauma centers are a well-known problem in sparsely populated regions with a low hospital density. Transfusion of red blood cell concentrates (RBC) and plasma improves outcome of trauma patients with severe bleeding. Helicopter emergency services (HEMS) are frequently employed to provide early advanced medical care and to reduce time to hospital admission. Supplying HEMS with blood products allows prehospital transfusion and may help to prevent exsanguination or prolonged hemorrhagic shock. We have investigated the maintenance of blood product quality under air transport conditions and the logistical steps to introduce a HEMS blood depot into routine practice. METHODS: A risk analysis was performed and a validation plan developed. A special, commercially available transport container for blood products was identified. Maintenance of temperature conditions between 2 and 6°C in the box were monitored at ambient temperatures up to 35°C over 48 h. Quality of blood products before and after helicopter air transport were evaluated including (1) for RBCs: hemoglobin, hematocrit, hemolysis rate; (2) for thawed plasma: aPTT, INR, single clotting factor activities. The logistics for blood supply of the regional HEMS were developed by the transfusion service of the Greifswald University Hospital in collaboration with the in-hospital transport team, the HEMS team, and the HEMS operator. RESULTS: The transport container maintained a temperature below 6°C up to 36 h at 35°C ambient temperature. Vibration during helicopter operation did not impair quality of RBC and thawed plasma. To provide blood products for HEMS at least two transport containers and an additional set of cooling tiles is needed as the cooling tiles need a special temperature priming over 20 h. The two boxes were used at alternate days. To reduce wastage, RBCs and thawed plasmas were exchanged every fourth day and reintegrated into the blood bank inventory for further in-hospital use. CONCLUSIONS: Supplying HEMS with RBCs and plasma is feasible. Helicopter transport has no negative impact on blood product quality. The logistic challenges require close collaboration between the HEMS team and the blood transfusion service.
RESUMEN
The quality of biospecimens stored in a biobank depends tremendously on the technical personnel responsible for processing, storage, and release of biospecimens. Adequate training of these biobank employees would allow harmonization of correct sample handling and thus ensure a high and comparable quality of samples across biobank locations. However, in Germany there are no specific training opportunities for technical biobank staff. To understand the educational needs of the technical personnel a web-based survey was sent to all national biobanks via established e-mail registers. In total, 79 biobank employees completed the survey, including 43 technicians. The majority of the participating technical personnel stated that they had worked in a biobank for less than three years and had never participated in an advanced training. Three-quarters of the technicians indicated that they were not able to understand English content instantly. Based on these results and the results of a workshop with 16 biobank technicians, 41 learning objectives were formulated. These learning objectives can be used as a basis for advanced training programs for technical personnel in biobanks. Setting up courses based on the identified learning objectives for this group of biobank staff could contribute to harmonization and sustainability of biospecimen quality.
RESUMEN
In 2017, in the Polish-German transborder area of West Pomerania, Mecklenburg-Western Pomerania, and Brandenburg, in collaboration with two centers in Warsaw, a partnership in the field of newborn screening (NBS) for severe primary immunodeficiency diseases (PID), mainly severe combined immunodeficiency (SCID), was initiated. SCID, but also some other severe PID, is a group of disorders characterized by the absence of T and/or B and NK cells. Affected infants are susceptible to life-threatening infections, but early detection gives a chance for effective treatment. The prevalence of SCID in the Polish and German populations is unknown but can be comparable to other countries (1:50,000-100,000). SCID NBS tests are based on real-time polymerase chain reaction (qPCR) and the measurement of a number of T cell receptor excision circles (TREC), kappa-deleting recombination excision circles (KREC), and beta-actin (ACTB) as a quality marker of DNA. This method can also be effective in NBS for other severe PID with T- and/or B-cell lymphopenia, including combined immunodeficiency (CID) or agammaglobulinemia. During the 14 months of collaboration, 44,287 newborns were screened according to the ImmunoIVD protocol. Within 65 positive samples, seven were classified to immediate recall and 58 requested a second sample. Examination of the 58 second samples resulted in recalling one newborn. Confirmatory tests included immunophenotyping of lymphocyte subsets with extension to TCR repertoire, lymphoproliferation tests, radiosensitivity tests, maternal engraftment assays, and molecular tests. Final diagnosis included: one case of T-BlowNK+ SCID, one case of atypical Tlow BlowNK+ CID, one case of autosomal recessive agammaglobulinemia, and one case of Nijmegen breakage syndrome. Among four other positive results, three infants presented with T- and/or B-cell lymphopenia due to either the mother's immunosuppression, prematurity, or unknown reasons, which resolved or almost normalized in the first months of life. One newborn was classified as truly false positive. The overall positive predictive value (PPV) for the diagnosis of severe PID was 50.0%. This is the first population screening study that allowed identification of newborns with T and/or B immunodeficiency in Central and Eastern Europe.
Asunto(s)
Linfocitos B/inmunología , Pruebas Inmunológicas , Tamizaje Neonatal , Enfermedades de Inmunodeficiencia Primaria/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Antígenos de Linfocitos T/genética , Inmunodeficiencia Combinada Grave/diagnóstico , Linfocitos T/inmunología , Diagnóstico Precoz , Femenino , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Alemania , Humanos , Recién Nacido , Masculino , Fenotipo , Polonia , Valor Predictivo de las Pruebas , Enfermedades de Inmunodeficiencia Primaria/genética , Enfermedades de Inmunodeficiencia Primaria/inmunología , Reproducibilidad de los Resultados , Inmunodeficiencia Combinada Grave/genética , Inmunodeficiencia Combinada Grave/inmunologíaRESUMEN
Machine learning methods show promise to translate univariate biomarker findings into clinically useful multivariate decision support systems. At current, works in major depressive disorder have predominantly focused on neuroimaging and clinical predictor modalities, with genetic, blood-biomarker, and cardiovascular modalities lacking. In addition, the prediction of rehospitalization after an initial inpatient major depressive episode is yet to be explored, despite its clinical importance. To address this gap in the literature, we have used baseline clinical, structural imaging, blood-biomarker, genetic (polygenic risk scores), bioelectrical impedance and electrocardiography predictors to predict rehospitalization within 2 years of an initial inpatient episode of major depression. Three hundred and eighty patients from the ongoing 12-year Bidirect study were included in the analysis (rehospitalized: yes = 102, no = 278). Inclusion criteria was age ≥35 and <66 years, a current or recent hospitalisation for a major depressive episode and complete structural imaging and genetic data. Optimal performance was achieved with a multimodal panel containing structural imaging, blood-biomarker, clinical, medication type, and sleep quality predictors, attaining a test AUC of 67.74 (p = 9.99-05). This multimodal solution outperformed models based on clinical variables alone, combined biomarkers, and individual data modality prognostication for rehospitalization prediction. This finding points to the potential of predictive models that combine multimodal clinical and biomarker data in the development of clinical decision support systems.
Asunto(s)
Trastorno Depresivo Mayor/fisiopatología , Trastorno Depresivo Mayor/terapia , Aprendizaje Automático , Readmisión del Paciente , Adulto , Anciano , Antidepresivos/uso terapéutico , Área Bajo la Curva , Biomarcadores , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Trastorno Depresivo Mayor/diagnóstico por imagen , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Resultado del TratamientoRESUMEN
BACKGROUND: Measuring the glucose concentration in whole blood samples is critical due to unsatisfactory glycolysis inhibition. Previous studies showed that Terumo tubes were superior, but they were taken off the European market in 2016 and alternatives were required. This initiated the present evaluation of glucose stability in five available tube types. METHODS: Venous blood samples were collected from 61 healthy volunteers to test tubes supplied by Terumo (two sets), Greiner FC-Mix, BD FX-Mixture and BD serum. After sampling, the contents were thoroughly mixed and centrifuged within an hour. The glucose concentrations were determined and the samples resuspended except for BD serum tubes (gel barrier). The first 30 samples were stored at room temperature and the remaining 31 at 4°C. After 24, 48, 72 and 96 h, all tubes were (re)centrifuged, and glucose concentration measurements were repeated. RESULTS: Changes in glucose concentrations over time differed significantly between the investigated tube types and to a certain extent between the two storing conditions. Glycolysis was most evident in the BD FX-mixture tubes. Good glucose stability was observed in samples retrieved form BD serum and Greiner tubes. The stability in both Terumo tubes was comparable to that in other studies. Although Greiner and both Terumo tubes are supposed to contain the same glycolysis inhibitor, glucose stability differed between these tubes. CONCLUSIONS: We showed that Greiner is an acceptable alternative to Terumo and that glucose in serum that was rapidly separated from corpuscles by a gel barrier is stable for an extended time.
Asunto(s)
Análisis Químico de la Sangre/instrumentación , Glucemia/análisis , Glucemia/química , Ácido Cítrico/farmacología , Inhibidores Enzimáticos/farmacología , Glucólisis , Hexoquinasa/antagonistas & inhibidores , Humanos , Fosfofructoquinasa-1/antagonistas & inhibidores , Fosfopiruvato Hidratasa/antagonistas & inhibidores , Fluoruro de Sodio/farmacologíaRESUMEN
BACKGROUND: Newborn screening (NBS) is an established screening procedure in many countries worldwide, aiming at the early detection of inborn errors of metabolism. For decades, dried blood spots have been the standard specimen for NBS. The procedure of blood collection is well described and standardized and includes many critical pre-analytical steps. We examined the impact of contamination of some anticipated common substances on NBS results obtained from dry spot samples. This possible pre-analytical source of uncertainty has been poorly examined in the past. METHODS: Capillary blood was obtained from 15 adult volunteers and applied to 10 screening filter papers per volunteer. Nine filter papers were contaminated without visible trace. The contaminants were baby diaper rash cream, baby wet wipes, disinfectant, liquid infant formula, liquid infant formula hypoallergenic (HA), ultrasonic gel, breast milk, feces, and urine. The differences between control and contaminated samples were evaluated for 45 NBS quantities. We estimated if the contaminations might lead to false-positive NBS results. RESULTS: Eight of nine investigated contaminants significantly altered NBS analyte concentrations and potentially caused false-positive screening outcomes. A contamination with feces was most influential, affecting 24 of 45 tested analytes followed by liquid infant formula (HA) and urine, affecting 19 and 13 of 45 analytes, respectively. CONCLUSIONS: A contamination of filter paper samples can have a substantial effect on the NBS results. Our results underline the importance of good pre-analytical training to make the staff aware of the threat and ensure reliable screening results.
Asunto(s)
Recolección de Muestras de Sangre/métodos , Pruebas con Sangre Seca/métodos , Tamizaje Neonatal/métodos , Adulto , Recolección de Muestras de Sangre/instrumentación , Pruebas con Sangre Seca/instrumentación , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Recién Nacido , Papel , IncertidumbreRESUMEN
OBJECTIVES: Determination of cardiac troponin (cTn) is central in the emergency department (ED) for the diagnosis of myocardial infarction. In view of adverse effects of long waiting time on patient outcome, implementation of point-of-care-testing (POCT) is suggested if the turn-around-time is longer than 60min. The present study aimed to determine the 99th percentile and imprecision of two POCT in a healthy population measuring cTnI and cTnT and compare these analytical characteristics against three central laboratory test (CLT) for cTnI. DESIGN & METHODS: CTnI and cTnT were determined in parallel by means of the AQT90 FLEX analyzer in about 2250 plasma samples from individuals with known health status. Results were compared to previously determined performance data of three CLT. RESULTS: The 99th percentile of cTnI in the POCT was determined at 19ng/L, the lowest concentration with an imprecision of 10% was reached at 22ng/L while an imprecision of 20% was reached at 13ng/L. Age, sex, or physical activity did not affect the 99th percentile of cTnI. Compared to CLT the AQT90 cTnI POCT the analytical performance was equivalent. The cTnT POCT could not be assessed due a considerable number of high values and an inadequate imprecision profile. CONCLUSION: While the cTnI POCT showed analytical performance comparable to CLT, the results of the cTnT assay on the same device did not suffice to determine a reliable 99th percentile. The present evaluation supports the usage of the cTnI POCT, but application of the cTnT POCT needs further evaluation.
Asunto(s)
Servicio de Urgencia en Hospital , Sistemas de Atención de Punto , Troponina I/sangre , Adulto , Femenino , Humanos , Masculino , Factores de TiempoRESUMEN
BACKGROUND AND AIM: Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers. Several local and systemic therapies are available for patients with HCC depending on the stage of the disease. In clinical practice, treatment decision-making, and sequencing may be very heterogeneous. METHODS: In this study, we retrospectively analyzed treatment algorithms in 2101 patients with HCC treated from 2000 to 2015 at Hannover Medical School, Germany. RESULTS: Transarterial chemoembolization was the most common initial treatment (n = 545; 25.9%), followed by resection (n = 435, 20.7%), local-ablative procedures (n = 283, 13.5%), systemic therapies (n = 275, 13.1%), and liver transplantation (n = 52; 2.5%). Most patients were treated only once (n = 960; 59.6%). A total of 433 (26.9%) and 160 (9.9%) patients received a second line and third line treatment after recurrent or progressive disease. Patients with more than one treatment line were diagnosed at significantly earlier disease stages (P < 0.001). Using binary logistic regression, AFP ≤ 200 µg/L, albumin > 36 g/L, and small tumor size (≤50 mm) were identified as predictors of achieving more than one treatment line. Subsequent treatment stage migration to a therapy suggested for the next advanced stage occurred only in 56.9%, whereas 43.1% received treatments suggested for earlier disease stages. Only 16% of all treated patients received systemic therapy in the salvage setting. CONCLUSION: Most patients were treated only once, and only a minority of patients received systemic treatment. The high dropout rate for subsequent therapies needs to be considered within therapy decision-making. There is an urgent need for prospective studies to define the best time point when to switch patients from local to systemic therapies.
Asunto(s)
Carcinoma Hepatocelular/terapia , Neoplasias Hepáticas/terapia , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/patología , Quimioembolización Terapéutica/estadística & datos numéricos , Toma de Decisiones Clínicas , Protocolos Clínicos , Terapia Combinada , Diagnóstico Precoz , Femenino , Alemania , Hepatectomía/estadística & datos numéricos , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patología , Trasplante de Hígado/estadística & datos numéricos , Masculino , Estadificación de Neoplasias , Estudios Retrospectivos , Centros de Atención TerciariaRESUMEN
BACKGROUND: The innovative pneumatic tube system (iPTS) transports one sample at a time without the use of cartridges and allows rapid sending of samples directly into the bulk loader of a laboratory automation system (LAS). We investigated effects of the iPTS on samples and turn-around time (TAT). METHODS: During transport, a mini data logger recorded the accelerations in three dimensions and reported them in arbitrary area under the curve (AUC) units. In addition representative quantities of clinical chemistry, hematology and coagulation were measured and compared in 20 blood sample pairs transported by iPTS and courier. RESULTS: Samples transported by iPTS were brought to the laboratory (300 m) within 30 s without adverse effects on the samples. The information retrieved from the data logger showed a median AUC of 7 and 310 arbitrary units for courier and iPTS transport, respectively. This is considerably below the reported limit for noticeable hemolysis of 500 arbitrary units. CONCLUSIONS: iPTS reduces TAT by reducing the hands-on time and a fast transport. No differences in the measurement results were found for any of the investigated 36 analytes between courier and iPTS transport. Based on these findings the iPTS was cleared for clinical use in our hospital.
Asunto(s)
Automatización de Laboratorios , Análisis Químico de la Sangre/instrumentación , Recolección de Muestras de Sangre/instrumentación , Humanos , Factores de TiempoRESUMEN
BACKGROUND: Long transportation times of samples can occur due to centralization of laboratories, and also in, for instance epidemiological multicenter studies with one core laboratory. Unsatisfactory glycolysis inhibition is known to threaten the correct measurements of glucose concentration in patient samples. In former studies Terumo Glycaemia tubes proved to be superior to other anticoagulant systems for time periods of up to 24 h. We investigated long-term stability of glucose concentration in Terumo Glycaemia tubes for up to 96 h at room temperature and imitated transport conditions by continuous sample shaking. METHODS: Human venous blood samples were collected from 40 healthy blood donors using Terumo Glycaemia tubes. Immediately after sampling, tubes were mixed according to the manufactures recommendations. To simulate transportation conditions samples were placed on a shaker for the entire study period and maintained at room temperature. Samples were (re)centrifuged at 0, 24, 36, 48, 72 and 96 h prior to measuring glucose concentration. The glucose concentration at 0 h was used as baseline for evaluation of long-term stability. RESULTS: The recovery of glucose was 100% throughout the study, including the 96-h measurements. Deviations of single glucose measurements were within the imprecision of the measurement procedure. CONCLUSIONS: Terumo Glycaemia tubes can effectively stabilize glucose in whole blood samples kept at room temperature on a shaker during a 96-h time period. Therefore, we consider Terumo Glycaemia tubes as a suitable glucose stabilizing tube for long intervals between sample collection and glucose quantification.
Asunto(s)
Recolección de Muestras de Sangre/instrumentación , Técnicas de Laboratorio Clínico/instrumentación , Glucosa/farmacocinética , Glucemia/análisis , Glucemia/metabolismo , Recolección de Muestras de Sangre/normas , Estabilidad de Medicamentos , Ácido Edético/química , Humanos , Materiales ManufacturadosRESUMEN
The applications of low-temperature plasma are not only confined to decontamination and sterilization but are also found in the medical field in terms of wound and skin treatment. For the improvement of already established and also for new plasma techniques, in-depth knowledge on the interactions between plasma and microorganism is essential. In an initial study, the interaction between growing Bacillus subtilis and argon plasma was investigated by using a growth chamber system suitable for low-temperature gas plasma treatment of bacteria in liquid medium. In this follow-up investigation, a second kind of plasma treatment-namely air plasma-was applied. With combined proteomic and transcriptomic analyses, we were able to investigate the plasma-specific stress response of B. subtilis toward not only argon but also air plasma. Besides an overlap of cellular responses due to both argon and air plasma treatment (DNA damage and oxidative stress), a variety of gas-dependent cellular responses such as growth retardation and morphological changes were observed. Only argon plasma treatments lead to a phosphate starvation response whereas air plasma induced the tryptophan operon implying damage by photooxidation. Biological findings were supported by the detection of reactive plasma species by optical emission spectroscopy and Fourier transformed infrared spectroscopy measurements.
Asunto(s)
Aire , Argón/farmacología , Bacillus subtilis/efectos de los fármacos , Gases em Plasma/farmacología , Estrés Fisiológico , Argón/química , Bacillus subtilis/crecimiento & desarrollo , Bacillus subtilis/metabolismo , Daño del ADN , Perfilación de la Expresión Génica , Viabilidad Microbiana , Estrés Oxidativo , Espectroscopía de Fotoelectrones , Gases em Plasma/química , Proteómica , Especies Reactivas de Oxígeno/metabolismo , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Plasma medicine and also decontamination of bacteria with physical plasmas is a promising new field of life science with huge interest especially for medical applications. Despite numerous successful applications of low temperature gas plasmas in medicine and decontamination, the fundamental nature of the interactions between plasma and microorganisms is to a large extent unknown. A detailed knowledge of these interactions is essential for the development of new as well as for the enhancement of established plasma-treatment procedures. In the present work we introduce for the first time a growth chamber system suitable for low temperature gas plasma treatment of bacteria in liquid medium. We have coupled the use of this apparatus to a combined proteomic and transcriptomic analyses to investigate the specific stress response of Bacillus subtilis 168 cells to treatment with argon plasma. The treatment with three different discharge voltages revealed not only effects on growth, but also clear evidence of cellular stress responses. B. subtilis suffered severe cell wall stress, which was made visible also by electron microscopy, DNA damages and oxidative stress as a result of exposure to plasma. These biological findings were supported by the detection of reactive plasma species by OES measurements.
Asunto(s)
Bacillus subtilis/crecimiento & desarrollo , Descontaminación/instrumentación , Gases em Plasma/metabolismo , Bacillus subtilis/citología , Frío , Descontaminación/métodos , Diseño de Equipo , Perfilación de la Expresión Génica , Análisis de Secuencia por Matrices de OligonucleótidosRESUMEN
Twin-arginine protein translocation (Tat) pathways are required for transport of folded proteins across bacterial, archaeal and chloroplast membranes. Recent studies indicate that Tat has evolved into a mainstream pathway for protein secretion in certain halophilic archaea, which thrive in highly saline environments. Here, we investigated the effects of environmental salinity on Tat-dependent protein secretion by the Gram-positive soil bacterium Bacillus subtilis, which encounters widely differing salt concentrations in its natural habitats. The results show that environmental salinity determines the specificity and need for Tat-dependent secretion of the Dyp-type peroxidase YwbN in B. subtilis. Under high salinity growth conditions, at least three Tat translocase subunits, namely TatAd, TatAy and TatCy, are involved in the secretion of YwbN. Yet, a significant level of Tat-independent YwbN secretion is also observed under these conditions. When B. subtilis is grown in medium with 1% NaCl or without NaCl, the secretion of YwbN depends strictly on the previously described "minimal Tat translocase" consisting of the TatAy and TatCy subunits. Notably, in medium without NaCl, both tatAyCy and ywbN mutants display significantly reduced exponential growth rates and severe cell lysis. This is due to a critical role of secreted YwbN in the acquisition of iron under these conditions. Taken together, our findings show that environmental conditions, such as salinity, can determine the specificity and need for the secretion of a bacterial Tat substrate.
Asunto(s)
Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Ambiente , Proteínas de Transporte de Membrana/metabolismo , Salinidad , Bacillus subtilis/genética , Bacillus subtilis/crecimiento & desarrollo , Proteínas Bacterianas/genética , Northern Blotting , Regulación Bacteriana de la Expresión Génica , Prueba de Complementación Genética , Hierro/metabolismo , Fenotipo , Plásmidos/genética , Transcripción GenéticaRESUMEN
The gram-positive pathogen Staphylococcus aureus secretes various proteins into its extracellular milieu. Bioinformatics analyses have indicated that most of these proteins are directed to the canonical Sec pathway, which consists of the translocation motor SecA and a membrane-embedded channel composed of the SecY, SecE, and SecG proteins. In addition, S. aureus contains an accessory Sec2 pathway involving the SecA2 and SecY2 proteins. Here, we have addressed the roles of the nonessential channel components SecG and SecY2 in the biogenesis of the extracellular proteome of S. aureus. The results show that SecG is of major importance for protein secretion by S. aureus. Specifically, the extracellular accumulation of nine abundant exoproteins and seven cell wall-bound proteins was significantly affected in an secG mutant. No secretion defects were detected for strains with a secY2 single mutation. However, deletion of secY2 exacerbated the secretion defects of secG mutants, affecting the extracellular accumulation of one additional exoprotein and one cell wall protein. Furthermore, an secG secY2 double mutant displayed a synthetic growth defect. This might relate to a slightly elevated expression of sraP, encoding the only known substrate for the Sec2 pathway, in cells lacking SecG. Additionally, the results suggest that SecY2 can interact with the Sec1 channel, which would be consistent with the presence of a single set of secE and secG genes in S. aureus.