Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Eur J Pharm Biopharm ; 199: 114297, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38641228

RESUMO

Spray-drying of nucleic acid-based drugs designed for gene therapy or gene knockdown is associated with many advantages including storage stability and handling as well as the possibility of pulmonary application. The encapsulation of nucleic acids in nanoparticles prior to spray-drying is one strategy for obtaining efficient formulations. This, however, strongly relies on the definition of optimal nanoparticles, excipients and spray-drying conditions. Among polymeric nanoparticles, polyethylenimine (PEI)-based complexes with or without chemical modifications have been described previously as very efficient for gene or oligonucleotide delivery. The tyrosine-modification of linear or branched low molecular weight PEIs, or of polypropylenimine (PPI) dendrimers, has led to high complex stability, improved cell uptake and transfection efficacy as well as high biocompatibility. In this study, we identify optimal spray-drying conditions for PEI-based nanoparticles containing large plasmid DNA or small siRNAs, and further explore the spray-drying of nanoparticles containing chemically modified polymers. Poly(vinyl alcohol) (PVA), but not trehalose or lactose, is particularly well-suited as excipient, retaining or even enhancing transfection efficacies compared to fresh complexes. A big mesh size is critically important as well, while the variation of the spray-drying temperature plays a minor role. Upon spray-drying, microparticles in a âˆ¼ 3.3 - 8.5 µm size range (laser granulometry) are obtained, dependent on the polymers. Upon their release from the spray-dried material, the nanoparticles show increased sizes and markedly altered zeta potentials as compared to their fresh counterparts. This may contribute to their high efficacy that is seen also after prolonged storage of the spray-dried material. We conclude that these spray-dried systems offer a great potential for the preparation of nucleic acid drug storage forms with facile reconstitution, as well as for their direct pulmonary application as dry powder.


Assuntos
DNA , Nanopartículas , Polietilenoimina , RNA Interferente Pequeno , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/química , Nanopartículas/química , Polietilenoimina/química , DNA/administração & dosagem , DNA/química , Humanos , Técnicas de Transferência de Genes , Secagem por Atomização , Transfecção/métodos , Polipropilenos/química , Excipientes/química , Tamanho da Partícula , Plasmídeos/administração & dosagem , Dessecação/métodos , Álcool de Polivinil/química
2.
Environ Sci Technol ; 57(2): 1092-1102, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36599497

RESUMO

Underground hydrogen storage (UHS) has been proposed as one option for storage of excess energy from renewable sources. Depleted gas reservoirs appear suitable, but at the same time, they may be environments with potentially high microbial abundances and activities. Hydrogen (H2) is one of the most energetic substrates in such environments, and many microorganisms are able to oxidize H2, potentially leading to loss of H2 or other unwanted reactions like production of, e.g., H2S, clogging, or corrosion. This study addressed the potential of H2 consumption by naturally abundant microorganisms in formation fluid from a gas field at near in situ pressure and temperature conditions. Microbial H2 consumption was evident at ambient and 100 bar and tolerated pressure variations reflecting cycles of H2 storage. Temperature strongly influenced the activity with higher activity at 30 °C but lower activity at 60 °C. The activity was sulfate-dependent, and sulfide was produced. The microbial community composition changed during H2 consumption with an increase in sulfate-reducing prokaryotes (SRP). Thus, the presence of an SRP-containing, H2-consuming microbial community with activity at UHS-relevant pressure and temperature conditions was shown and should be taken into account when planning UHS at this and other sites.


Assuntos
Microbiota , Campos de Petróleo e Gás , Gás Natural , Sulfatos , Hidrogênio
3.
Int J Womens Health ; 14: 1881-1895, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36601385

RESUMO

Introduction: Despite that NOTES produces at least matchable clinical long-term results when compared to laparoscopy, still a restraint within the medical community and among patients is evident. Consequently, it might be meaningful to evaluate factors of patient's NOTES perception to promote its acceptance. NOTES is still quite novel and questionnaires regarding its perception by the public is still lacking even so in the Middle East. Aim of our survey is to investigate the viewpoint of female healthcare staff on NOTES. Materials and Methods: A total of 350 questionnaires along with written information about Minimally Invasive Surgery and NOTES were distributed among the female staff in a Tertiary-care Hospital in Abu Dhabi, 257 were returned completely anonymously and voluntarily and entered into a database with a response rate of 73%. We surveyed factors like religion, medical background, age as well as history of previous laparoscopy, endoscopy, birth and other aspects that may impact a woman's perception of both transgastric and transvaginal NOTES for cholecystectomy and ovariectomy, respectively. Results: Univariate analyses revealed the majority of Muslim women to be more receptive to NOTES as a choice of surgical technique for cholecystectomy and for ovariectomy, respectively, when compared to Christians and Hindus. However, when compared to Muslims, Christian and Hindu groups had a larger share of medical professions. Women with a medical background would opt significantly less for NOTES. Among younger women, NOTES cholecystectomy was refused due to anxiety concerning future pregnancies and sexual dysfunction. Multinomial logistic regression analysis determined medical background and with independent predictive value for the overall choice of interventional technique (p<0.001). Marital status played a significant role only in the comparison of laparoscopy vs transgastric NOTES when performing cholecystectomy and ovariectomy (p<0.01). Conclusion: In this first study emanating from the Middle East, medical education and partly life stage rather than cross-cultural differences seem to influence NOTES perception in women.

4.
Gut ; 71(11): 2179-2193, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-34598978

RESUMO

OBJECTIVE: Human white adipose tissue (AT) is a metabolically active organ with distinct depot-specific functions. Despite their locations close to the gastrointestinal tract, mesenteric AT and epiploic AT (epiAT) have only scarcely been investigated. Here, we aim to characterise these ATs in-depth and estimate their contribution to alterations in whole-body metabolism. DESIGN: Mesenteric, epiploic, omental and abdominal subcutaneous ATs were collected from 70 patients with obesity undergoing Roux-en-Y gastric bypass surgery. The metabolically well-characterised cohort included nine subjects with insulin sensitive (IS) obesity, whose AT samples were analysed in a multiomics approach, including methylome, transcriptome and proteome along with samples from subjects with insulin resistance (IR) matched for age, sex and body mass index (n=9). Findings implying differences between AT depots in these subgroups were validated in the entire cohort (n=70) by quantitative real-time PCR. RESULTS: While mesenteric AT exhibited signatures similar to those found in the omental depot, epiAT was distinct from all other studied fat depots. Multiomics allowed clear discrimination between the IS and IR states in all tissues. The highest discriminatory power between IS and IR was seen in epiAT, where profound differences in the regulation of developmental, metabolic and inflammatory pathways were observed. Gene expression levels of key molecules involved in AT function, metabolic homeostasis and inflammation revealed significant depot-specific differences with epiAT showing the highest expression levels. CONCLUSION: Multi-omics epiAT signatures reflect systemic IR and obesity subphenotypes distinct from other fat depots. Our data suggest a previously unrecognised role of human epiploic fat in the context of obesity, impaired insulin sensitivity and related diseases.


Assuntos
Resistência à Insulina , Tecido Adiposo/metabolismo , Humanos , Insulina/metabolismo , Resistência à Insulina/genética , Obesidade/genética , Obesidade/metabolismo , Proteoma/metabolismo
5.
Int J Med Robot ; 17(6): e2317, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34297475

RESUMO

BACKGROUND: Insulinomas are rare insulin-producing pancreatic neuroendocrine tumours leading to severe episodes of hypoglycaemia. Surgery is the predominant curative therapy. METHODS: We report here the first paediatric case of an insulinoma of the pancreatic body resected completely robotically under ultrasound guidance in a 10-year-old male with multiple endocrine neoplasia type 1. The port set-up was adapted for the narrowed dimensions of the paediatric peritoneal space. We comment on technical key steps for the organ-preserving procedure that was performed in close proximity to critical anatomic structures, with supporting video. Preoperative diagnostics, including endoscopic ultrasound, to determine surgical management are highlighted. RESULTS: Following an uneventful post-operative course, the boy was discharged on day 11 with normalised glucose-metabolism. A pseudocyst developing after 4 weeks was treated with endoscopic stenting. CONCLUSIONS: The applicability of a robotic surgical system in limited space conditions such as found in the paediatric abdominal cavity is demonstrated here for pancreatic surgery.


Assuntos
Insulinoma , Neoplasias Pancreáticas , Procedimentos Cirúrgicos Robóticos , Criança , Humanos , Insulinoma/cirurgia , Masculino , Pâncreas/cirurgia , Pancreatectomia , Neoplasias Pancreáticas/cirurgia
6.
Cancers (Basel) ; 12(9)2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32927768

RESUMO

Cancer stem cells (CSC) are crucial mediators of cancer relapse. Here, we isolated two primary human colorectal cancer cell lines derived from a rectal neuroendocrine carcinoma (BKZ-2) and a colorectal adenocarcinoma (BKZ-3), both containing subpopulations with potential stem-like properties. Protein expression of CSC-markers prominin-1 and CD44 antigen was significantly higher for BKZ-2 and BKZ-3 in comparison to well-established colon carcinoma cell lines. High sphere-formation capacity further confirmed the existence of a subpopulation with potential stem-like phenotype. Epithelial-mesenchymal transition markers as well as immune checkpoint ligands were expressed more pronounced in BKZ-2. Both cell populations demonstrated N-myc proto-oncogene (NMYC) copy number gain. Myc proto-oncogene (MYC)/NMYC activity inhibitor all-trans retinoic acid (ATRA) significantly reduced the number of tumor spheres for both and the volume of BKZ-2 spheres. In contrast, the sphere volume of ATRA-treated BKZ-3 was increased, and only BKZ-2 cell proliferation was reduced in monolayer culture. Treatment with KJ-Pyr-9, a specific inhibitor of MYC/NMYC-myc-associated factor X interaction, decreased survival by the induction of apoptosis of both. In summary, here, we present the novel colorectal cancer cell lines BKZ-2 and BKZ-3 as promising cellular in vitro models for colorectal carcinomas and identify the MYC/NMYC molecular pathway involved in CSC-induced carcinogenesis with relevant therapeutic potential.

7.
Int J Mol Sci ; 21(17)2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32899390

RESUMO

We previously demonstrated that clinical administration of mobilized CD133+ bone marrow stem cells (BMSC) accelerates hepatic regeneration. Here, we investigated the potential of platelets to modulate CD133+BMSC homing to hepatic endothelial cells and sequestration to warm ischemic livers. Modulatory effects of platelets on the adhesion of CD133+BMSC to human and mouse liver-sinusoidal- and micro- endothelial cells (EC) respectively were evaluated in in vitro co-culture systems. CD133+BMSC adhesion to all types of EC were increased in the presence of platelets under shear stress. This platelet effect was mostly diminished by antagonization of P-selectin and its ligand P-Selectin-Glyco-Ligand-1 (PSGL-1). Inhibition of PECAM-1 as well as SDF-1 receptor CXCR4 had no such effect. In a model of the isolated reperfused rat liver subsequent to warm ischemia, the co-infusion of platelets augmented CD133+BMSC homing to the injured liver with heightened transmigration towards the extra sinusoidal space when compared to perfusion conditions without platelets. Extravascular co-localization of CD133+BMSC with hepatocytes was confirmed by confocal microscopy. We demonstrated an enhancing effect of platelets on CD133+BMSC homing to and transmigrating along hepatic EC putatively depending on PSGL-1 and P-selectin. Our insights suggest a new mechanism of platelets to augment stem cell dependent hepatic repair.


Assuntos
Antígeno AC133/metabolismo , Plaquetas/fisiologia , Endotélio Vascular/citologia , Fígado/citologia , Glicoproteínas de Membrana/metabolismo , Células-Tronco Mesenquimais/citologia , Selectina-P/metabolismo , Animais , Endotélio Vascular/metabolismo , Fígado/metabolismo , Masculino , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Wistar
8.
Sci Rep ; 10(1): 15136, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934256

RESUMO

The ASA score is known to be an independent predictor of complications and mortality following colorectal surgery. We evaluated early outcome in the initiation phase of a robotic oncological colorectal resection program in dependence of comorbidity and learning curve. 43 consecutive colorectal cancer patients (median age: 74 years) who underwent robotic surgery were firstly analysed defined by physical status (group A = ASA1 + 2; group B = ASA3). Secondly, outcome was evaluated relating to surgery date (group E: early phase; group L: late phase). There were no differences among groups A and B with regard to gender, BMI, skin-to-skin operative times (STS), N- and M-status, hospital-stay as well as overall rate of complications according to Dindo-Clavien and no one-year mortality. GroupA when compared to group B demonstrated significantly lower mean age (65.5 years ± 11.4 years vs 75.8 years ± 8.9 years), T-stage and ICU-stay. When separately analyzed for patients age ICU-stay was comparable (> 75 years vs. < 75 years). Group E and L demonstrated comparable characteristics and early outcome except more frequent lymphatic fistulas in group E. STS was reduced in group L compared to group E. Beyond learning curve aspects in our series, we could demonstrate that patient's physical condition according to ASA rather than age may have an impact on early outcome in the initial phase of a robotic oncological colorectal program.


Assuntos
Neoplasias Colorretais/mortalidade , Cirurgia Colorretal/mortalidade , Curva de Aprendizado , Tempo de Internação/estatística & dados numéricos , Complicações Pós-Operatórias/mortalidade , Procedimentos Cirúrgicos Robóticos/mortalidade , Fatores Etários , Idoso , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Complicações Pós-Operatórias/epidemiologia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
10.
BMC Surg ; 19(1): 72, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262302

RESUMO

BACKROUND: Several studies have demonstrated a direct correlation between lymph node yield and survival after colectomy for cancer. Complete mesocolic excision (CME) in right colectomy (RC) reduces local recurrence but is technically demanding. Here we report our early single center experience with robotic right colectomy comparing our standardized bottom-to-up (BTU) approach of robotic RC with CME and central vessel ligation (CVL) facilitated by a suprapubic access with the "classical" medial-to-lateral (MTL) strategy. METHODS: A 4-step BTU approach of robotic RC guided by embryonal planes in the process of retrocolic mobilization with suprapubic port placement was performed in the BTU-group (n = 24; all with intention to treat cancer). In step 1 CME was initiated with caudolateral mobilization of the right colon guided by the fascia of Toldt across the duodenum and up to the Trunk of Henle. Subsequently, dissection was performed BTU right of the middle supramesenteric vessels with central ileocolic vessel ligation in step 2. Subsequent to separation of the transverse retromesenteric space and completion of mobilization the hepatic flexure in step 3, the transverse mesocolon was then transected right of the middle colic vessels in step 4. An extracorporeal side to side anastomosis was performed. We compared the outcome of the BTU-group with a MTL-group (n = 7). RESULTS: Patient characteristics like age, gender, BMI, comorbidity (ASA) and M-status were comparable among groups. There was no conversion. Overall complication rate was 35.5%. We experienced no anastomoses insufficiency, grade Dindo/Clavien III/IV complication or mortality in this study. Type I and II complications and surgical characteristics incl. OR-time, ICU- and hospital-stay were comparable between the two groups. However, the lymph node yield was superior in the BTU-group (mean 40.2 ± 17.1) when compared with the MTL-group (16,3 nodes ±8.5; p <  0,001). CONCLUSIONS: Compared to the classical MTL approach, robotic suprapubic BTU RC changes from a search of the layers bordering the oncological dissection to a consequent utilization of the planes as a retro-mesocolic guide during CME. The BTU strategy could bear the potential to increase the lymph node yield. Robotic systems may provide the technical requirements to combine advantages of both open and minimally invasive RC.


Assuntos
Colectomia/métodos , Neoplasias do Colo/cirurgia , Mesocolo/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/patologia , Dissecação , Feminino , Humanos , Tempo de Internação , Ligadura , Linfonodos/patologia , Masculino , Estudos Retrospectivos
11.
Blood Cells Mol Dis ; 77: 142-148, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31075617

RESUMO

BACKGROUND: We previously demonstrated CD133+ bone marrow stem cells (BMSC) to promote hepatic proliferation for liver regeneration. Here, we evaluated the capacity of CD133+BMSC to utilize platelets for homing to vasculature and concomitant controlling their aggregability upon ADP stimulation. METHODS: CD133+BMSC and platelets were co-cultured along micro endothelial cells under variable flow conditions and tested for homing levels along vasculature. Aggregometry and FACS analysis were utilized to evaluate platelet reactivity following co-incubation ±â€¯CD133+BMSC. RT-PCR and FACS analyses served to characterize ADP degrading ectonucleoside triphosphate diphosphohydrolase-1 (ectoNTPDase-1/CD39) expression on various cell types. RESULTS: Platelets attracted human CD133+BMSC to autologous micro endothelium under shear stress unaffected by ADP stimulation. However, CD133+BMSC inhibited ADP-mediated platelet activation and aggregation. Latter was dependent on ectoNTPDase-1 expression levels. Platelet aggregatory control was increased with CD133+BMSC compared to CD133+PHSC. Different effects of those stem cell subtypes positively correlated with their FACS-detected expression levels of ectoNTPDase-1. CONCLUSION: We provide evidence that CD133+BMSC are capable of controlling ADP-dependent platelet aggregation and activation by direct interaction dependent on cellular expression of ectoNTPDase-1. Whether different capacities of BMSC modulate platelet-depending thrombogenicity at sites of regeneration impact effectiveness and adverse event profiles of regenerative treatment requires further evaluation.


Assuntos
Antígeno AC133/metabolismo , Antígenos CD/metabolismo , Apirase/metabolismo , Plaquetas/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Ativação Plaquetária , Difosfato de Adenosina/metabolismo , Comunicação Celular , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Fibroblastos/metabolismo , Humanos , Regeneração Hepática , Agregação Plaquetária
12.
Gut ; 68(3): 445-452, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29298872

RESUMO

OBJECTIVES: Sedation has been established for GI endoscopic procedures in most countries, but it is also associated with an added risk of complications. Reported complication rates are variable due to different study methodologies and often limited sample size. DESIGNS: Acute sedation-associated complications were prospectively recorded in an electronic endoscopy documentation in 39 study centres between December 2011 and August 2014 (median inclusion period 24 months). The sedation regimen was decided by each study centre. RESULTS: A total of 368 206 endoscopies was recorded; 11% without sedation. Propofol was the dominant drug used (62% only, 22.5% in combination with midazolam). Of the sedated patients, 38 (0.01%) suffered a major complication, and overall mortality was 0.005% (n=15); minor complications occurred in 0.3%. Multivariate analysis showed the following independent risk factors for all complications: American Society of Anesthesiologists class >2 (OR 2.29) and type and duration of endoscopy. Of the sedation regimens, propofol monosedation had the lowest rate (OR 0.75) compared with midazolam (reference) and combinations (OR 1.0-1.5). Compared with primary care hospitals, tertiary referral centres had higher complication rates (OR 1.61). Notably, compared with sedation by a two-person endoscopy team (endoscopist/assistant; 53.5% of all procedures), adding another person for sedation (nurse, physician) was associated with higher complication rates (ORs 1.40-4.46), probably due to higher complexity of procedures not evident in the multivariate analysis. CONCLUSIONS: This large multicentre registry study confirmed that severe acute sedation-related complications are rare during GI endoscopy with a very low mortality. The data are useful for planning risk factor-adapted sedation management to further prevent sedation-associated complications in selected patients. TRIAL REGISTRATION NUMBER: DRKS00007768; Pre-results.


Assuntos
Sedação Consciente/efeitos adversos , Endoscopia Gastrointestinal/efeitos adversos , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Sedação Consciente/mortalidade , Endoscopia Gastrointestinal/métodos , Endoscopia Gastrointestinal/mortalidade , Endoscopia Gastrointestinal/estatística & dados numéricos , Feminino , Alemanha/epidemiologia , Humanos , Hipnóticos e Sedativos/efeitos adversos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Propofol/efeitos adversos , Estudos Prospectivos , Sistema de Registros , Fatores de Risco , Fatores de Tempo , Adulto Jovem
13.
J Gastric Cancer ; 19(4): 473-483, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31897349

RESUMO

Surgical therapy for adenocarcinoma of the esophagogastric junction II requires distal esophagectomy, in which a transhiatal management of the lower esophagus is critical. The 'dorsal track control' (DTC) maneuver presented here facilitates the atraumatic handling of the distal esophagus, in preparation for a circular-stapled esophagojejunostomy. It is based on a ventral semicircular incision in the distal esophagus, with an intact dorsal wall for traction control of the esophagus. The maneuver facilitates the proper placement of the purse-string suture, up to its tying (around the anvil), thus minimizing the manipulation of the remaining esophagus. Furthermore, the dorsally-exposed inner wall surface of the ventrally-opened esophagus serves as a guiding chute that eases anvil insertion into the esophageal lumen. We performed this novel technique in 21 cases, enabling a safe anastomosis up to 10 cm proximal to the Z-line. No anastomotic insufficiency was observed. The DTC technique improves high transhiatal esophagojejunostomy.

14.
Front Microbiol ; 8: 763, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28503172

RESUMO

The microbial community response to petroleum seepage was investigated in a whole round sediment core (16 cm length) collected nearby natural hydrocarbon seepage structures in the Caspian Sea, using a newly developed Sediment-Oil-Flow-Through (SOFT) system. Distinct redox zones established and migrated vertically in the core during the 190 days-long simulated petroleum seepage. Methanogenic petroleum degradation was indicated by an increase in methane concentration from 8 µM in an untreated core compared to 2300 µM in the lower sulfate-free zone of the SOFT core at the end of the experiment, accompanied by a respective decrease in the δ13C signal of methane from -33.7 to -49.5‰. The involvement of methanogens in petroleum degradation was further confirmed by methane production in enrichment cultures from SOFT sediment after the addition of hexadecane, methylnapthalene, toluene, and ethylbenzene. Petroleum degradation coupled to sulfate reduction was indicated by the increase of integrated sulfate reduction rates from 2.8 SO42-m-2 day-1 in untreated cores to 5.7 mmol SO42-m-2 day-1 in the SOFT core at the end of the experiment, accompanied by a respective accumulation of sulfide from 30 to 447 µM. Volatile hydrocarbons (C2-C6 n-alkanes) passed through the methanogenic zone mostly unchanged and were depleted within the sulfate-reducing zone. The amount of heavier n-alkanes (C10-C38) decreased step-wise toward the top of the sediment core and a preferential degradation of shorter (C30) was seen during the seepage. This study illustrates, to the best of our knowledge, for the first time the development of methanogenic petroleum degradation and the succession of benthic microbial processes during petroleum passage in a whole round sediment core.

15.
FEMS Microbiol Ecol ; 91(6)2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25994158

RESUMO

The Arctic Baffin Bay between Canada and Greenland is sea ice-covered during the majority of the year, restricting primary production to the summer months. Sediments receive low amounts of mostly terrestrial- and less marine-derived organic matter. To study microbial communities constrained by physicochemical conditions changing with distance from land and ocean depth, we applied high-throughput 16S rRNA gene sequencing and compared sequence diversity with biogeochemical parameters in 40 different sediment samples. Samples originated from seven cores down to 470 cm below seafloor along a shelf-to-basin transect. Bacterial diversity decreased faster with depth in basin than in shelf sediments, suggesting higher organic matter content sustained diversity into greater depths. All samples were dominated by Betaproteobacteria (mostly order Burkholderiales), which were especially abundant in basin sediments with low organic carbon and high Mn and Fe pore water concentrations. Strong statistical correlations between concentrations of reduced Mn and/or Fe and the relative abundances of Betaproteobacteria suggest that this group is involved in metal reduction in Baffin Bay sediments. Dehalococcoidia (phylum Chloroflexi) were abundant in all samples, especially in shelf sediments with high organic content. This study indicates that Mn and/or Fe play important roles structuring microbial communities in Arctic sediments poor in organic matter.


Assuntos
Betaproteobacteria/genética , Chloroflexi/genética , Sedimentos Geológicos/microbiologia , Ferro/metabolismo , Manganês/metabolismo , Archaea/genética , Archaea/isolamento & purificação , Regiões Árticas , Sequência de Bases , Baías , Betaproteobacteria/isolamento & purificação , Biodiversidade , Canadá , Chloroflexi/isolamento & purificação , Groenlândia , Consórcios Microbianos/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
16.
Environ Sci Technol ; 48(2): 1306-14, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24320192

RESUMO

Carbon Capture and Storage (CCS) is currently under debate as large-scale solution to globally reduce emissions of the greenhouse gas CO2. Depleted gas or oil reservoirs and saline aquifers are considered as suitable reservoirs providing sufficient storage capacity. We investigated the influence of high CO2 concentrations on the indigenous bacterial population in the saline formation fluids of a natural gas field. Bacterial community changes were closely examined at elevated CO2 concentrations under near in situ pressures and temperatures. Conditions in the high pressure reactor systems simulated reservoir fluids i) close to the CO2 injection point, i.e. saturated with CO2, and ii) at the outer boundaries of the CO2 dissolution gradient. During the incubations with CO2, total cell numbers remained relatively stable, but no microbial sulfate reduction activity was detected. After CO2 release and subsequent transfer of the fluids, an actively sulfate-respiring community was re-established. The predominance of spore-forming Clostridiales provided evidence for the resilience of this taxon against the bactericidal effects of supercritical (sc)CO2. To ensure the long-term safety and injectivity, the viability of fermentative and sulfate-reducing bacteria has to be considered in the selection, design, and operation of CCS sites.


Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Dióxido de Carbono/farmacologia , Pressão Hidrostática , Viabilidade Microbiana/efeitos dos fármacos , Gás Natural/microbiologia , Campos de Petróleo e Gás/microbiologia , Bactérias/efeitos dos fármacos , Bactérias/genética , Contagem de Colônia Microbiana , Genes Bacterianos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Sulfatos/metabolismo
17.
Adv Biochem Eng Biotechnol ; 142: 1-94, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24240533

RESUMO

This chapter gives the reader a practical introduction into microbial enhanced oil recovery (MEOR) including the microbial production of natural gas from oil. Decision makers who consider the use of one of these technologies are provided with the required scientific background as well as with practical advice for upgrading an existing laboratory in order to conduct microbiological experiments. We believe that the conversion of residual oil into natural gas (methane) and the in situ production of biosurfactants are the most promising approaches for MEOR and therefore focus on these topics. Moreover, we give an introduction to the microbiology of oilfields and demonstrate that in situ microorganisms as well as injected cultures can help displace unrecoverable oil in place (OIP). After an initial research phase, the enhanced oil recovery (EOR) manager must decide whether MEOR would be economical. MEOR generally improves oil production but the increment may not justify the investment. Therefore, we provide a brief economical assessment at the end of this chapter. We describe the necessary state-of-the-art scientific equipment to guide EOR managers towards an appropriate MEOR strategy. Because it is inevitable to characterize the microbial community of an oilfield that should be treated using MEOR techniques, we describe three complementary start-up approaches. These are: (i) culturing methods, (ii) the characterization of microbial communities and possible bio-geochemical pathways by using molecular biology methods, and (iii) interfacial tension measurements. In conclusion, we hope that this chapter will facilitate a decision on whether to launch MEOR activities. We also provide an update on relevant literature for experienced MEOR researchers and oilfield operators. Microbiologists will learn about basic principles of interface physics needed to study the impact of microorganisms living on oil droplets. Last but not least, students and technicians trying to understand processes in oilfields and the techniques to examine them will, we hope, find a valuable source of information in this review.


Assuntos
Metano/metabolismo , Methanococcales/metabolismo , Methanomicrobiales/metabolismo , Methanosarcinales/metabolismo , Petróleo/metabolismo , Thermococcales/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Consórcios Microbianos/fisiologia , Gás Natural , Campos de Petróleo e Gás , Salinidade , Tensoativos/metabolismo , Temperatura
18.
Adv Biochem Eng Biotechnol ; 142: 95-121, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24311044

RESUMO

This chapter gives the reader an introduction into the microbiology of deep geological systems with a special focus on potential geobiotechnological applications and respective risk assessments. It has been known for decades that microbial activity is responsible for the degradation or conversion of hydrocarbons in oil, gas, and coal reservoirs. These processes occur in the absence of oxygen, a typical characteristic of such deep ecosystems. The understanding of the responsible microbial processes and their environmental regulation is not only of great scientific interest. It also has substantial economic and social relevance, inasmuch as these processes directly or indirectly affect the quantity and quality of the stored oil or gas. As outlined in the following chapter, in addition to the conventional hydrocarbons, new interest in such deep subsurface systems is rising for different technological developments. These are introduced together with related geomicrobiological topics. The capture and long-termed storage of large amounts of carbon dioxide, carbon capture and storage (CCS), for example, in depleted oil and gas reservoirs, is considered to be an important options to mitigate greenhouse gas emissions and global warming. On the other hand, the increasing contribution of energy from natural and renewable sources, such as wind, solar, geothermal energy, or biogas production leads to an increasing interest in underground storage of renewable energies. Energy carriers, that is, biogas, methane, or hydrogen, are often produced in a nonconstant manner and renewable energy may be produced at some distance from the place where it is needed. Therefore, storing the energy after its conversion to methane or hydrogen in porous reservoirs or salt caverns is extensively discussed. All these developments create new research fields and challenges for microbiologists and geobiotechnologists. As a basis for respective future work, we introduce the three major topics, that is, CCS, underground storage of gases from renewable energy production, and the production of geothermal energy, and summarize the current stat of knowledge about related geomicrobiological and geobiotechnological aspects in this chapter. Finally, recommendations are made for future research.


Assuntos
Dióxido de Carbono/química , Energia Geotérmica , Halobacteriales/genética , Microbiologia do Solo , Bactérias Redutoras de Enxofre/genética , Anaerobiose , Ecossistema , Humanos , Metano/química , Consórcios Microbianos/genética , Gás Natural/estatística & dados numéricos , Campos de Petróleo e Gás , Petróleo/estatística & dados numéricos , RNA Ribossômico 16S/classificação , RNA Ribossômico 16S/genética
19.
ChemMedChem ; 8(7): 1067-85, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23671017

RESUMO

Lead optimization of a high-throughput screening hit led to the rapid identification of aminopyrimidine ZK 304709, a multitargeted CDK and VEGF-R inhibitor that displayed a promising preclinical profile. Nevertheless, ZK 304709 failed in phase I studies due to dose-limited absorption and high inter-patient variability, which was attributed to limited aqueous solubility and off-target activity against carbonic anhydrases. Further lead optimization efforts to address the off-target activity profile finally resulted in the introduction of a sulfoximine group, which is still a rather unusual approach in medicinal chemistry. However, the sulfoximine series of compounds quickly revealed very interesting properties, culminating in the identification of the nanomolar pan-CDK inhibitor BAY 1000394, which is currently being investigated in phase I clinical trials.


Assuntos
Antineoplásicos/farmacologia , Quinases Ciclina-Dependentes/antagonistas & inibidores , Descoberta de Drogas , Neoplasias Experimentais/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Sulfóxidos/farmacologia , Neoplasias do Colo do Útero/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/síntese química , Quinases Ciclina-Dependentes/metabolismo , Relação Dose-Resposta a Droga , Feminino , Células HeLa , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Modelos Moleculares , Estrutura Molecular , Peso Molecular , Neoplasias Experimentais/enzimologia , Neoplasias Experimentais/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/síntese química , Pirimidinas/administração & dosagem , Pirimidinas/síntese química , Ratos , Relação Estrutura-Atividade , Sulfóxidos/administração & dosagem , Sulfóxidos/síntese química , Neoplasias do Colo do Útero/enzimologia , Neoplasias do Colo do Útero/metabolismo
20.
Appl Microbiol Biotechnol ; 97(9): 3827-41, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23546422

RESUMO

Arsenic causes threats for environmental and human health in numerous places around the world mainly due to its carcinogenic potential at low doses. Removing arsenic from contaminated sites is hampered by the occurrence of several oxidation states with different physicochemical properties. The actual state of arsenic strongly depends on its environment whereby microorganisms play important roles in its geochemical cycle. Due to its toxicity, nearly all organisms possess metabolic mechanisms to resist its hazardous effects, mainly by active extrusion, but also by extracellular precipitation, chelation, and intracellular sequestration. Some microbes are even able to actively use various arsenic compounds in their metabolism, either as an electron donor or as a terminal electron acceptor for anaerobic respiration. Some microorganisms can also methylate inorganic arsenic, probably as a resistance mechanism, or demethylate organic arsenicals. Bioavailability of arsenic in water and sediments is strongly influenced by such microbial activities. Therefore, understanding microbial reactions to arsenic is of importance for the development of technologies for improved bioremediation of arsenic-contaminated waters and environments. This review gives an overview of the current knowledge on bacterial interactions with arsenic and on biotechnologies for its detoxification and removal.


Assuntos
Arsênio/metabolismo , Bactérias/metabolismo , Biotecnologia/métodos , Biodegradação Ambiental , Reatores Biológicos/microbiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA