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1.
Clin Lab ; 68(10)2022 Oct 01.
Article in English | MEDLINE | ID: mdl-36250831

ABSTRACT

BACKGROUND: The most important factor in the diagnosis of AKI is to accurately and early detect the damage that occurs in the kidney before the filtration capacity of the kidney decreases. Therefore, we discussed the use of NGAL and L-FABP in the early diagnosis of acute kidney injury, evaluation of clinical severity and prognosis as well as prediction of hemodialysis decision in this prospective study. METHODS: We studied 82 participants which included 41 patients aged 18 years and older with the diagnosis of acute kidney injury. We compared the renal function tests collected at 0 and 6 hours with the plasma NGAL and LFABP levels measured using ELISA. Acute kidney injury was defined as serum creatinine increase of 0.3 mg/dL in the last 48 hours, or an increase more than 1.5 times, or an increase in the basal serum creatinine value in the last seven days, or less than 0.5/mL/kg of urine volume within six hours. We tested the power of these new biomarkers in the early diagnosis, and prediction of hemodialysis and survival of the patients with AKI using ROC analysis. RESULTS: Fifteen (36.6%) of the patients were anuric and 26 (63.4%) were oliguric. Twenty-one (51.2%) patients were KDIGO Stage 3. Seventeen (41.5%) patients underwent hemodialysis. In the patient group, the mean NGAL level was 289.7 ± 117.4 ng/mL and the mean L-FABP level was 232.7 ± 72.8. Eleven (26.9%) of 41 patients died within the first 24 hours. In the dead patients, the mean plasma NGAL level was statistically significantly high (p = 0.005). The mean NGAL level was found to be statistically increased in correlation with the severity of acute kidney injury in patients (p < 0.05). To predict acute kidney injury, the ROC analysis showed that the area under the curve (AUC) was 0.819 (95% confidence interval (CI): 0.729 - 0.909) (p < 0.001) for plasma NGAL level, and the area under the curve (AUC) was 0.891 (95% confidence interval (CI): 0.822 - 0.959) for plasma L-FABP level (p < 0.001). CONCLUSIONS: Our study provides evidence that NGAL and L-FABP are effective biomarkers for early detection of AKI as well as predicting clinical severity and hemodialysis.


Subject(s)
Acute Kidney Injury , Lipocalins , Acute Kidney Injury/diagnosis , Acute Kidney Injury/therapy , Acute-Phase Proteins , Biomarkers , Creatinine , Fatty Acid-Binding Proteins , Gelatinases/metabolism , Humans , Lipocalin-2 , Liver/metabolism , Prospective Studies , Proto-Oncogene Proteins
2.
Clin Otolaryngol ; 46(4): 796-801, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33580555

ABSTRACT

OBJECTIVES: To evaluate the effect of laryngopharyngeal reflux (LPR) and antireflux treatment on peak nasal inspiratory airflow (PNIF). DESIGN: Prospective observational study was conducted. SETTING: Tertiary otorhinolaryngology clinic. PARTICIPANTS: Adults with LPR and healthy controls. MAIN OUTCOME MEASURES: PNIF measurements were performed on 60 patients who applied with complaints suggestive of LPR having higher Reflux Symptom Index (RSI) (>13) and Reflux Finding Scores (RFS) scores (>7). Proton pump inhibitor (PPI) treatment was started and PNIF measurements were repeated two months later. A total of 100 patients without any history of LPR and sinonasal disease were included in the study. RESULTS: A statistically significant increase was observed in PNIF values after proton pump inhibitor treatment. The mean PNIF values of the LPR patients were 133.83 ± 27.99 L/min and 149.92 ± 23.23 L/min before and after treatment, respectively. The mean PNIF value in the control group was 145.0 ± 25.92 L/min. PNIF values were significantly lower in the LPR relative to the control group (P < .05). CONCLUSION: Laryngopharyngeal reflux decreases PNIF. This negative effect on PNIF disappears after antireflux medication. The results of the study indicate that PNIF measurements may be an appropriate method for clinical diagnosis of LPR and evaluation of treatment results.


Subject(s)
Airway Resistance/drug effects , Laryngopharyngeal Reflux/drug therapy , Proton Pump Inhibitors/therapeutic use , Adult , Case-Control Studies , Female , Humans , Laryngoscopy , Male , Prospective Studies , Respiratory Function Tests
3.
J Pediatr Hematol Oncol ; 42(6): e434-e439, 2020 08.
Article in English | MEDLINE | ID: mdl-32324696

ABSTRACT

Hemophagocytic lymphohistiocytosis (HLH) is characterized by uncontrolled and excessive immune responses with high mortality. We aimed to define mortality-related parameters in HLH secondary to primary immunodeficiency (PID). A total of 28 patients with HLH between the years 2013 and 2017 were enrolled in the study. The patients were evaluated in 2 groups including PID with hypopigmentation (n=7) (Chédiak-Higashi syndrome [CHS] and Griscelli syndrome type 2 [GS2]) and other PIDs (n=21). The median age of the study population was 23 (4.3 to 117.0) months at the time of the diagnosis of HLH. Central nervous system involvement was recorded in 7 (GS2/CHS patients [n=4], other PIDs [n=3], P=0.026), and death was observed in 9 patients (GS2/CHS patients [n=1], other PIDs [n=8], P=0.371). Five patients (3 GS2/CHS and 2 other PID patients) underwent hematopoietic stem cell transplantation. Low serum albumin level was the only variable associated with the mortality and albumin levels less than the cut-off value of 3.07 g/dL increased mortality 5.8 times in patients with HLH secondary to PID. We presented a single-center experience consisting of patients with HLH secondary to PID with a mortality rate of 32.1%. Hypoalbuminemia was the only risk factor to increase the overall mortality rate of HLH.


Subject(s)
Chediak-Higashi Syndrome/mortality , Hematopoietic Stem Cell Transplantation/mortality , Lymphohistiocytosis, Hemophagocytic/mortality , Piebaldism/mortality , Primary Immunodeficiency Diseases/mortality , Chediak-Higashi Syndrome/complications , Child , Child, Preschool , Female , Follow-Up Studies , Humans , Infant , Lymphohistiocytosis, Hemophagocytic/complications , Lymphohistiocytosis, Hemophagocytic/etiology , Lymphohistiocytosis, Hemophagocytic/pathology , Lymphohistiocytosis, Hemophagocytic/therapy , Male , Piebaldism/complications , Primary Immunodeficiency Diseases/complications , Prognosis , Risk Factors , Survival Rate
4.
Int J Psychiatry Clin Pract ; 19(2): 148-54, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25363199

ABSTRACT

OBJECTIVE: Multiple sclerosis (MS) is a progressive disorder that results in demyelinization of the nerve fibers of the central nervous system. We aimed to determine chronobiological and mood features in patients with MS. METHODS: The sample comprised 75 patients with MS (54 women and 21 men) and 50 healthy individuals (38 women and 12 men). Sixty-three patients were relapsing-remitting MS and twelve patients had secondary progressive-type MS. Mood characteristics were assessed using subscales of the Profile of Mood States (POMS). Chronotypical characteristics were determined by the Morningness-Eveningness Questionnaire (MEQ). Univariate and structural equation modeling was applied to untangle the possible connections between variables. RESULTS: Both relapsing-remitting and secondary progressive patients scored higher on the depression-dejection and fatigue-inertia scales of the POMS than healthy individuals. Circadian preferences did not differ significantly between these groups. Patients using glatiramer acetate and other types of drugs had greater severity of functional impairment measured relative to interferon-beta treatment group. Glatiramer acetate had more negative effects on mood than interferon-beta therapy. This finding may be the result of significantly higher duration of disease and higher symptom severity scores in glatiramer acetate group. CONCLUSIONS: In the structural equation model, gender was found to be predictive for characteristics of mood.


Subject(s)
Affect/physiology , Affective Symptoms/physiopathology , Circadian Rhythm/physiology , Immunologic Factors/therapeutic use , Multiple Sclerosis/physiopathology , Severity of Illness Index , Adult , Female , Glatiramer Acetate/therapeutic use , Humans , Interferon-beta/therapeutic use , Male , Middle Aged , Multiple Sclerosis/drug therapy , Multiple Sclerosis/psychology , Sex Factors
5.
Extremophiles ; 18(4): 677-91, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24863363

ABSTRACT

The Capuchin Catacombs of Palermo, Italy, contain over 1800 mummies dating from the 16th to 20th centuries AD. Their environment is not conducive to the conservation of the remains due to, among other factors, water infiltration, which is producing salt efflorescences on the walls. A multiphasic approach was applied to investigate the halophilic microbiota present in the Catacombs. Enrichment cultures were conducted on media containing different NaCl concentrations, ranging from 3 to 20 %. For screening of the strains, the following two PCR-based methods were used and compared: fluorescence internal transcribed spacer PCR (f-ITS) and random amplification of polymorphic DNA (RAPD) analyses. Results derived from RAPD profiles were shown to be slightly more discriminative than those derived from f-ITS. In addition, the proteolytic and cellulolytic abilities were screened through the use of plate assays, gelatin agar and Ostazin Brilliant Red H-3B (OBR-HEC), respectively. Many of the strains isolated from the wall samples displayed proteolytic activities, such as all strains belonging to the genera Bacillus, Virgibacillus and Arthrobacter, as well as some strains related to the genera Oceanobacillus, Halobacillus and Idiomarina. In addition, many of the strains isolated from materials employed to stuff the mummies showed cellulolytic activities, such as those related to species of the genera Chromohalobacter and Nesterenkonia, as well as those identified as Staphylococcus equorum and Halomonas sp. Furthermore, many of the strains were pigmented ranging from yellow to a strong pink color, being directly related to the discoloration displayed by the materials.


Subject(s)
Bacteria/isolation & purification , Caves/microbiology , Microbiota , Mummies/microbiology , Salt Tolerance , Bacteria/genetics , Bacteria/metabolism , Italy , Polymorphism, Restriction Fragment Length
6.
Aerobiologia (Bologna) ; 29(2): 301-314, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23576841

ABSTRACT

In this study, we investigated and compared the microbial communities adhering to the obverse and the reverse sides of an oil painting on canvas exhibiting signs of biodeterioration. Samples showing no visible damage were investigated as controls. Air samples were also analysed, in order to investigate the presence of airborne microorganisms suspended in the indoor atmosphere. The diversity of the cultivable microorganisms adhering to the surface was analysed by molecular techniques, such as RAPD analysis and gene sequencing. DGGE fingerprints derived from DNA directly extracted from canvas material in combination with clone libraries and sequencing were used to evaluate the non-cultivable fraction of the microbial communities associated with the material. By using culture-dependent methods, most of the bacterial strains were found to be common airborne, spore-forming microorganisms and belonged to the phyla Actinobacteria and Firmicutes, whereas culture-independent techniques identified sequenced clones affiliated with members of the phyla Actinobacteria and Proteobacteria. The diversity of fungi was shown to be much lower than that observed for bacteria, and only species of Penicillium spp. could be detected by cultivation techniques. The selected strategy revealed a higher microbial diversity on the obverse than on the reverse side of the painting and the near absence of actively growing microorganisms on areas showing no visible damage. Furthermore, enzymatic activity tests revealed that the most widespread activities involved in biodeterioration were esterase and esterase lipase among the isolated bacterial strains, and esterase and N-acetyl-ß-glucosaminidase among fungi strains.

7.
Gen Hosp Psychiatry ; 34(2): 201-5, 2012.
Article in English | MEDLINE | ID: mdl-22177025

ABSTRACT

OBJECTIVE: Electroconvulsive therapy (ECT) consists of controlled convulsive seizure by electric stimulation of the brain. Although various electrocardiographic (ECG) changes have been reported during ECT, atrial conduction has not been studied extensively. The aim of the present study was to assess the effects of ECT on systemic arterial blood pressure and ECG parameters (P wave duration, P wave dispersion and heart rate). METHODS: Thirty depressive patients undergoing ECT were included. Echocardiographic examination was performed on all patients before ECT sessions to exclude systolic heart failure and diastolic dysfunction which may affect P wave duration and dispersion. Twelve-lead ECG records were obtained before the first ECT and after the third session of ECT. Blood pressure was measured before and after convulsive therapy session. RESULTS: Compared to baseline values, maximum P wave duration (99.3 ± 14.6 to 111.3 ± 8.2 ms, P=.001), P wave dispersion (50 ± 14.8 to 63.3 ± 10.3 ms, P=.001), and systolic (110.7 ± 12 to 116 ± 12.2 mmHg, P=.043) and diastolic blood pressures (70.7 ± 9.4 to 75.3 ± 8.2 mmHg, P=.028) were significantly increased after convulsive therapy session. CONCLUSIONS: We proposed that ECT alone or in combination with atypical antipsychotics or antidepressants may influence atrial conduction as evidenced by the significantly prolonged maximum P wave duration and P wave dispersion. Longer-term follow-up of patients undergoing ECT may be appropriate to evaluate the possible long-term outcomes of our short-term results.


Subject(s)
Depressive Disorder, Major/therapy , Electroconvulsive Therapy/adverse effects , Heart Conduction System/physiology , Adult , Depressive Disorder, Major/physiopathology , Electrocardiography , Female , Humans , Male , Turkey
8.
Psychosomatics ; 52(6): 544-9, 2011.
Article in English | MEDLINE | ID: mdl-22054624

ABSTRACT

OBJECTIVE: The aim of the present study was to investigate the relationship between nightmares and acute myocardial infarction (AMI) occurring during sleep, and also to evaluate the influence of several related factors. METHOD: The sample comprised AMI patients who had been admitted to the coronary care unit. The patients were grouped into two categories; the asleep-AMI group consisted of 36 patients who had the onset of symptoms of AMI during sleep, and the awake-AMI group included 183 patients who had AMI while they were awake. The sleep quality and dream anxiety for the 1-month interval before AMI were assessed with Pittsburgh Sleep Quality Index (PSQI) and Van Dream Anxiety Scale (VDAS), respectively. RESULTS: Asleep-AMI patients reported significantly poorer subjective sleep quality, significantly higher global PSQI scores, and displayed significantly higher nightmare frequency, difficulty in falling asleep after a nightmare, higher autonomic hyperactivity, dream recall frequency, daytime anxiety, psychological problems, and higher global dream anxiety scores than awake-AMI patients. CONCLUSION: The present study suggests that sleep anxiety and related emotions are associated with AMI during sleep.


Subject(s)
Anxiety/epidemiology , Dreams/psychology , Myocardial Infarction/epidemiology , Sleep Wake Disorders/epidemiology , Aged , Circadian Rhythm , Emotions , Female , Humans , Male , Middle Aged , Myocardial Infarction/physiopathology , Myocardial Infarction/psychology , Precipitating Factors , Self Report , Severity of Illness Index
9.
Chemosphere ; 68(10): 1929-36, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17418886

ABSTRACT

Although it has already been shown that calcareous stone can be consolidated by using a bacterially inoculated culture medium, a more user-friendly method is the in situ application of a sterile culture medium that is able to activate, among the microbial community of the stone, those bacteria with a potential for calcium carbonate precipitation. In order to test this new method for stone consolidation, non-sterilized decayed porous limestone was immersed in sterile nutritional media. Results were compared to those of the runs in which stone sterilized prior to the treatment was used. The effects of the microbial community on stone consolidation were determined by recording the evolution of the culture media chemistry. The treated stone was tested for mechanical resistance and porosity. Results demonstrate that the tested media were able to activate bacteria from the microbial community of the stone. As a consequence of the growth of these bacteria, an alkalinization occurred that resulted in calcium carbonate precipitation. The new precipitate was compatible with the substrate and consolidated the stone without pore plugging. Therefore, a good candidate to in situ consolidate decayed porous limestone is the application of a sterile culture medium with the characteristics specified in the present study.


Subject(s)
Calcium Carbonate/chemistry , Myxococcus xanthus/metabolism , Chemical Precipitation , Construction Materials , Refuse Disposal/methods
10.
Food Chem Toxicol ; 43(11): 1595-605, 2005 Nov.
Article in English | MEDLINE | ID: mdl-15993997

ABSTRACT

To assess the possibilities of a culture-independent monitoring of bacterial communities in the food chain, samples of salad from farming sites as well as corresponding, processed products in stores were analysed. The bacterial DNA was extracted using a modified soil extraction protocol. Amplification of 16S rDNA was carried out using primers specific for eubacteria and enterobacteriaceae. Fingerprints of 200/370 bp respectively were obtained by denaturing gradient gel electrophoresis (DGGE) analysis following PCR and nested PCR amplification. In parallel to DGGE analysis, clone libraries containing PCR fragments of the ribosomal gene were constructed and clones were screened by DGGE. DGGE analysis indicated a high diversity of bacterial communities in salad samples. Fingerprints indicated clearly reduced diversity of bacterial communities in processed samples from markets compared to field-grown salads. Surprisingly, primers pointed out in literature as specific for enterobacteriaceae did amplify pseudomonadeceae as well. Therefore, the more specific primers fD2 and rP1 were used subsequently in this study to amplify specific members of the family enterobacteriaceae. A total of 11 different 16S rDNA sequences were obtained and subjected to sequencing and phylogenetic affiliation. Sequences derived from the eubacterial clone library from organically farmed salad were affiliated to the family microbacteriaceae and pseudomonadaceae. In addition, a potential new genus within the family of enterobacteriaceae was detected. Furthermore, a sequence showing 98.9% similarity to Pseudomonas libaniensis (fluorescence subgroup) was found in a processed salad sample but not in the corresponding field samples. This species is generally known as an opportunistic pathogen. Whereas molecular based monitoring of bacterial communities in food still may need more experience and standardisation to detect specific bacteria present, the monitoring strategy presented in this paper, combining DGGE analysis with the construction of clone libraries, is an attractive method for culture-independent monitoring of changes of bacterial communities in the food chain.


Subject(s)
Electrophoresis, Gel, Pulsed-Field , Vegetables/microbiology , Cloning, Molecular , DNA Primers , DNA, Bacterial/biosynthesis , DNA, Bacterial/genetics , DNA, Bacterial/isolation & purification , Ethidium , Gene Library , Phylogeny , RNA, Bacterial/biosynthesis , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/biosynthesis , RNA, Ribosomal, 16S/genetics , Reverse Transcriptase Polymerase Chain Reaction
11.
Arch Microbiol ; 176(5): 347-54, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11702076

ABSTRACT

A molecular approach was chosen to analyse the correlation between bacterial colonisation and rosy discolouration of masonry and lime wall paintings of two historically important buildings in Austria and Germany. The applied molecular method included PCR amplification of genes encoding the small subunit rRNA of bacteria (16S rDNA), genetic fingerprinting by denaturing gradient gel electrophoresis (DGGE), construction of 16S rDNA clone libraries, and comparative phylogenetic sequence analyses. The bacterial community of one red-pigmented biofilm sampled in Herberstein (Austria) contained bacteria phylogenetically related to the genera Saccharopolyspora, Nocardioides, Pseudonocardia, Rubrobacter, and to a Kineococcus-like bacterium. The bacterial community of the second red-pigmented biofilm sampled in Herberstein contained bacteria related to Arthrobacter, Comamonas, and to Rubrobacter. Rubrobacter-related 16S rDNA sequences were the most abundant. In the red-pigmented biofilm sampled in Burggen (Germany), only Rubrobacter-related bacteria were identified. No Rubrobacter-related bacteria were detected in non-rosy biofilms. The majority of sequences (70%) obtained from the bacterial communities of the three investigated rosy biofilms were related to sequences of the genus Rubrobacter (red-pigmented bacteria), demonstrating a correlation between Rubrobacter-related bacteria and the phenomenon of rosy discolouration of masonry and lime wall paintings.


Subject(s)
Actinobacteria/classification , Actinobacteria/growth & development , Biofilms/growth & development , Construction Materials/microbiology , Paintings , Actinobacteria/genetics , Actinobacteria/isolation & purification , Austria , Christianity , Cloning, Molecular , DNA, Bacterial/analysis , Electrophoresis, Agar Gel/methods , Germany , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA
12.
J Microbiol Methods ; 47(3): 345-54, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11714525

ABSTRACT

Besides lichens and bacteria, fungi play a crucial role in the biodeterioration of historical glass. In the present paper, the fungal diversity on the surface of two historical church window glasses was investigated by 18S rDNA-based denaturing gradient gel electrophoresis (DGGE) analysis. 566-bp 18S rDNA-specific clone libraries were constructed with primer set NS1/NS2+10. Positive clones were reamplified with primer sets EF4/518rGC (426-bp fragments) and NS26/518rGC (316-bp fragments), amplicons were screened by DGGE and clustered according to their position in DGGE. Results indicated that fungal 18S rDNA clone libraries should be screened with at least two different primer sets to obtain the maximum number of different clones. For phylogenetic sequence analyses, clone inserts were sequenced and compared with 18S rDNA sequences listed in the EMBL database. Similarity values ranged from 93.7% to 99.81% to known fungi. Analyses revealed complex fungal communities consisting of members and relatives of the genera Aspergillus, Aureobasidium, Coniosporum, Capnobotryella, Engyodontium, Geomyces, Kirschsteiniothelia, Leptosphaeria, Rhodotorula, Stanjemonium, Ustilago, and Verticillium. The genera Geomyces and Aureobasidium were present on both glass surfaces. Some genera had not been detected on historical glass so far.


Subject(s)
Fungi/isolation & purification , Glass , Polymerase Chain Reaction/methods , Art , Cloning, Molecular , DNA, Fungal/genetics , DNA, Fungal/isolation & purification , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , DNA, Ribosomal/isolation & purification , Electrophoresis, Polyacrylamide Gel/methods , Fungi/classification , Fungi/genetics , Phylogeny , RNA, Ribosomal, 18S/genetics , Sequence Analysis, DNA
13.
Appl Environ Microbiol ; 67(10): 4891-5, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11571198

ABSTRACT

Several moderately halophilic gram-positive, spore-forming bacteria have been isolated by conventional enrichment cultures from damaged medieval wall paintings and building materials. Enrichment and isolation were monitored by denaturing gradient gel electrophoresis and fluorescent in situ hybridization. 16S ribosomal DNA analysis showed that the bacteria are most closely related to Halobacillus litoralis. DNA-DNA reassociation experiments identified the isolates as a population of hitherto unknown Halobacillus species.


Subject(s)
Construction Materials , Gram-Positive Bacteria/genetics , Gram-Positive Bacteria/isolation & purification , Paintings , Austria , Culture Media , Electrophoresis/methods , Gram-Positive Bacteria/classification , Gram-Positive Bacteria/growth & development , In Situ Hybridization, Fluorescence , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA
15.
J Microbiol Methods ; 45(2): 77-87, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11311392

ABSTRACT

The application of culture-independent techniques based on molecular biological methods, especially on the PCR amplification of 16S rRNA genes, attempts to overcome some shortcomings of conventional cultivation methods and reveals far more complex bacterial communities on art objects than can be shown by cultivation methods. One of the major challenges of investigating microbial growth on art objects by molecular means is the extraction of DNA, due to small sample amounts and PCR inhibitors. In the present study, we introduce a DNA extraction protocol, which allowed the extraction of PCR-amplifiable DNA from samples derived from lime wall paintings and loamy soil underground. The DNA extracts were used to amplify 16S ribosomal fragments, which were subsequently analyzed by denaturing gradient gel electrophoresis (DGGE). In parallel with the DGGE analysis, clone libraries containing PCR fragments of the ribosomal gene were constructed and clones were screened by DGGE. Clone libraries allow the inclusion of the entire 16S rDNA sequence in the phylogenetic analyses of microorganisms, providing a more reliable phylogenetic identification of microorganisms than is obtained from sequence analyses of excised and directly sequenced DGGE bands.


Subject(s)
Art , Bacteria/genetics , DNA, Bacterial/isolation & purification , Polymerase Chain Reaction/methods , Bacteria/growth & development , Cloning, Molecular , DNA Fingerprinting/methods , DNA, Bacterial/chemistry , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , DNA, Ribosomal/isolation & purification , Electrophoresis, Polyacrylamide Gel/methods , RNA, Ribosomal, 16S/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA
16.
Appl Environ Microbiol ; 64(12): 5016-9, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9835599

ABSTRACT

Klebsiella oxytoca CECT 4460 removes high nitrate loads from industrial wastewaters without accumulation of nitrite under optimal culture conditions; however, under nonoptimal conditions nitrite accumulates. This situation reflects an in vivo-limited functioning of nitrite reductase in this strain. As a way to overcome this limitation, an increase in the nitrite reductase gene dose in K. oxytoca CECT 4460 was considered. To achieve this, we cloned and transferred into this strain the Klebsiella pneumoniae nasB gene, which encodes assimilatory nitrite reductase (Lin et al., J. Bacteriol. 176:2551-2559, 1994). The delivery vector was either the wide-host-range plasmid pUPE2, in which the nasB gene is expressed from the Escherichia coli Plac promoter, or a mini-Tn5-Km vector, which upon random insertion in the host chromosome allowed expression of the nasB gene from an unidentified chromosomal host promoter. The effect of the increase in the dose of the nasB gene in K. oxytoca CECT 4460 on the accumulation of nitrite in the culture medium was tested in two recombinant strains. The results obtained showed that K. oxytoca CECT 4460 bearing pUPE2 accumulated 88% less nitrite than the wild-type strain, while the recombinant strain bearing the K. pneumoniae nasB gene in the host chromosome showed a 25% lower level of nitrite accumulation in the culture medium than that of the wild type.

17.
Appl Environ Microbiol ; 64(8): 2970-6, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9687459

ABSTRACT

The nitrate-tolerant organism Klebsiella oxytoca CECT 4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. We studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h-1, whereas with glycerol it was 0.45 h-1. In batch cultures K. oxytoca cells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite or ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrate or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (YC) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (YN) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed. In contrast to batch cultures, in continuous cultures glycerol and sucrose were utilized simultaneously, although the specific rate of sucrose consumption was higher than the specific rate of glycerol consumption. In continuous cultures double-nutrient-limited growth appeared with respect to the C/N ratio of the feed medium and the dilution rate, so that for a C/N ratio between 10 and 30 and a growth rate of 0.1 h-1 the process led to simultaneous and efficient removal of the C and N sources used. At a growth rate of 0.2 h-1 the zone of double limitation was between 8 and 11. This suggests that the regimen of double limitation is influenced by the C/N ratio and the growth rate. The results of these experiments were validated by pulse assays.


Subject(s)
Glycerol/metabolism , Klebsiella/growth & development , Klebsiella/metabolism , Nitrates/metabolism , Sucrose/metabolism , Culture Media , Kinetics
18.
Biotechnol Bioeng ; 58(5): 510-4, 1998 Jun 05.
Article in English | MEDLINE | ID: mdl-10099287

ABSTRACT

Two strains, a gram-negative bacterium Klebsiella oxytoca CECT 4460 and a gram-positive, mycelium-forming bacterium Arthrobacter globiformis CECT 4500, tolerant to up to 1 M nitrate, were isolated from the grounds of a munitions factory. Under strict aerobic conditions and with appropriate C-sources, growth of these bacteria took place when the nitrate concentration in the medium was below 150 mM. Optimal growth conditions regarding the culture medium composition for the biological removal of nitrate were established in batch cultures. Then, the system was scaled up to a 40-L pilot plant and operated under continuous conditions in a factory with direct waste streams from dinitroethylene glycol production after appropriate dilution with nontreated groundwaters. The level of nitrate in the effluent was below 0.5% of the initial N-load. Nitrite and ammonium were undetectable and the level of the C-source in the effluent was below 50 mg per L. On the basis of these results, we conclude that the system worked on site satisfactorily. Copyright 1998 John Wiley & Sons, Inc.

19.
Appl Environ Microbiol ; 63(5): 2071-3, 1997 May.
Article in English | MEDLINE | ID: mdl-16535614

ABSTRACT

Klebsiella oxytoca isolate 15 was isolated from the grounds of a nitration factory and was found to be tolerant to nitrate at concentrations up to 0.5 to 1 M. Physicochemical parameters for optimal growth conditions for K. oxytoca isolate 15 were established. Growth took place when the nitrate concentration in the medium was less than 150 mM, and full nitrate consumption required about 14 g of C per g of N. This strain was able to remove nitrate without accumulating nitrite. The system was scaled up to a 40-liter pilot plant and was operated on-site satisfactorily.

20.
Biodegradation ; 8(6): 393-9, 1997.
Article in English | MEDLINE | ID: mdl-15765585

ABSTRACT

A gram-positive strain identified as Arthrobacter globiformis CECT 4500, tolerant to up to 1 M nitrate, was isolated from the grounds of a munitions factory. Under strict aerobic conditions, this bacterium used a wide variety of C-sources to obtain the energy required for growth, which took place when the nitrate concentration in the medium was below 150 mM. Cells of this bacterium growing in the absence of nitrate were seen as individual cells or forming pairs, whereas cells grown in the presence of nitrate formed short filaments. With ethylene glycol as the C-source, optimal conditions for the full nitrate removal by Arthrobacter were established under laboratory conditions with wastewaters from the synthesis of dinitroethylene glycol.


Subject(s)
Arthrobacter/metabolism , Nitrates/metabolism , Arthrobacter/growth & development , Arthrobacter/ultrastructure , Biodegradation, Environmental , Culture Media , Ethylene Glycol/metabolism , Hazardous Waste , Nitrate Reductase , Nitrate Reductases/metabolism , Soil Microbiology
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