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Scientific Reports Dec 2022PmlR2, a class II LitR/CarH family transcriptional regulator, and PmSB-LOV, a "short" LOV-type blue light photoreceptor, are adjacently encoded in Pseudomonas mendocina...
PmlR2, a class II LitR/CarH family transcriptional regulator, and PmSB-LOV, a "short" LOV-type blue light photoreceptor, are adjacently encoded in Pseudomonas mendocina NBRC 14162. An effector protein for the "short" LOV-type photoreceptor in Pseudomonas has not yet been identified. Here, we show that PmlR2 is an effector protein of PmSB-LOV. Transcriptional analyses revealed that the expression of genes located near pmlR2 and its homolog gene, pmlR1, was induced in response to illumination. In vitro DNA-protein binding analyses showed that recombinant PmlR2 directly binds to the promoter region of light-inducible genes. Furthermore PmSB-LOV exhibited a typical LOV-type light-induced spectral change. Gel-filtration chromatography demonstrated that the illuminated PmSB-LOV was directly associated with PmlR2, whereas non-illuminated proteins did not interact. The inhibition of PmlR2 function following PmSB-LOV binding was verified by surface plasmon resonance: the DNA-binding ability of PmlR2 was specifically inhibited in the presence of blue light-illuminated-PmSB-LOV. An In vitro transcription assay showed a dose-dependent reduction in PmlR2 repressor activity in the presence of illuminated PmSB-LOV. Overall, evidence suggests that the DNA-binding activity of PmlR2 is inhibited by its direct association with blue light-activated PmSB-LOV, enabling transcription of light-inducible promoters by RNA polymerase.
Topics: Pseudomonas mendocina; Bacterial Proteins; Promoter Regions, Genetic; Protein Binding; DNA
PubMed: 36526696
DOI: 10.1038/s41598-022-26254-3 -
Foods (Basel, Switzerland) Nov 2022Alginate lyases (ALyases) have been widely applied in enzymatically degrading alginate for the preparation of alginate oligosaccharides (AOS), which possess a range of...
Alginate lyases (ALyases) have been widely applied in enzymatically degrading alginate for the preparation of alginate oligosaccharides (AOS), which possess a range of excellent physiological benefits including immunoregulatory, antivirus, and antidiabetic properties. Among the characterized ALyases, the number of ALyases with strict substrate specificity which possess potential in directed preparation of AOS is quite small. ALyases of polysaccharides lyase (PL) 5 family have been reported to perform poly--D-mannuronic acid (Poly-M) substrate specificity. However, there have been fewer studies with a comprehensive characterization and comparison of PL 5 family ALyases. In this study, a putative PL 5 family ALyase PMD was cloned from and expressed in . The novel ALyase presented maximum activity at 30 °C and pH 7.0. PMD displayed pH stability properties under the range of pH 5 to pH 9, which retained more than 80% relative activity, even when incubated for 48 h. Product analysis indicated that PMD might be an endolytic ALyase with strict Poly M substrate specificity and yield disaccharide and trisaccharide as main products. In addition, residues K58, R66, Y248, and R344 were proposed to be the potential key residues for catalysis via site-directed mutation. Detailed characterization of PMD and comprehensive comparisons could supply some different information about properties of PL 5 ALyases which might be helpful for its application in the directed production of AOS.
PubMed: 36360141
DOI: 10.3390/foods11213527 -
Environmental Health Insights 2022Antimicrobial resistance (AMR) is one of the top 10 public health threats. One approach to tackling the AMR menace could involve expanding the range of AMR surveillance...
BACKGROUND
Antimicrobial resistance (AMR) is one of the top 10 public health threats. One approach to tackling the AMR menace could involve expanding the range of AMR surveillance domains to include hospital wastewater (HWW), a domain that has largely been overlooked by researchers.
AIM
To evaluate the occurrence of multidrug-resistant bacteria in hospital wastewater of the Korle Bu Teaching Hospital (KBTH).
METHODOLOGY
This was a longitudinal study involving 288 HWW samples consecutively collected across 12 weeks from the pool of wastewater emanating from 2 critical care units of KBTH-The Child Health Unit and the Maternity Unit-on Mondays and Thursdays, each week. The samples were cultured for bacteria, which were identified using the Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) technique and subjected to antimicrobial susceptibility testing via the Kirby-Bauer method.
RESULTS
In total, 294 bacteria of 23 different types, all being Gram-negative, were isolated from the 288 samples. The predominant ones were (30.6%, n = 90), (11.2%, n = 33), (10.9%, n = 32), (5.8%, n = 17), and (5.4%, n = 16). The prevalence of multidrug resistance among the isolates was 55.4% (n = 163). Moreover, the prevalence of extended-spectrum beta-lactamase (ESBL) producers was 15.6% (n = 46). accounted for the most ESBL-producing organisms (28.9%, n = 26).
CONCLUSION
The wastewater generated by the Maternity and Child Health Units of KBTH harbored a wide range of multidrug resistant bacteria, with a good proportion of these being ESBL producers, and the predominant one being . The study thus identifies the wastewater of KBTH as an important source of multidrug resistant organisms, and underscores the significance of appropriate treatment of wastewater of the hospital and other clinical, and related settings prior to its discharge.
PubMed: 36311334
DOI: 10.1177/11786302221130613 -
Bioresource Technology Oct 2022The bioaugmentation potential of aerobic granular sludge (AGS) was investigated using heterotrophic nitrification-aerobic denitrification (HN-AD) bacterial consortium to...
Nitrogen removal intensification of aerobic granular sludge through bioaugmentation with "heterotrophic nitrification-aerobic denitrification" consortium during petroleum wastewater treatment.
The bioaugmentation potential of aerobic granular sludge (AGS) was investigated using heterotrophic nitrification-aerobic denitrification (HN-AD) bacterial consortium to improve nitrogen removal during petroleum wastewater treatment. An efficient HN-AD consortium was constructed by mixing Pseudomonas mendocina K0, Brucella sp. K1, Pseudomonas putida T4 and Paracoccus sp. T9. AGS bioaugmented by immobilized HN-AD consortium enhanced nitrogen removal, which showed NH-N and TN removal efficiency of 92.4% and 79.8%, respectively. The immobilized consortium addition facilitated larger AGS formation, while granules > 2.0 mm accounted for 16.7% higher than that of control (6.7%). Further, the abundance of napA gene was 4-times higher in the bioaugmented AGS as compared to the control, which demonstrated the long-term stability of HN-AD consortium in the bioreactor. The bioaugmented AGS also showed a higher abundance of xenobiotics biodegradation and nitrogen metabolism. These results highlight that bioaugmentation of AGS technology could be effectively used for enhanced denitrification of petroleum wastewater.
Topics: Aerobiosis; Bacteria, Aerobic; Bioreactors; Denitrification; Heterotrophic Processes; Nitrification; Nitrogen; Petroleum; Sewage; Wastewater; Water Purification
PubMed: 35926555
DOI: 10.1016/j.biortech.2022.127719 -
Chemosphere Nov 2022Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to...
Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to improve the biodegradative process of this polymer. The mixture of Pr. megaterium and Ps. mendocina was highly effective at biodegrading the PBAT, and after eight weeks of soil incubation, approximately 84% of the PBAT film weight was lost. Mixtures of the other two species also positively affected the synergistic degradation of PBAT film in the soil, but the mixture of three species had a negative effect. The residual PBAT film microstructure clearly demonstrated the degradation of PBAT, and the degree of degradation was related to the different species. Cleavage of the PBAT film ester bond after soil microbial action affected its properties. The incubation of PBAT in soil that contained these species affected soil dehydrogenase and soil lipase in particular. The secretion of lipase by these species could play an important role in the degradation of PBAT in the soil.
Topics: Adipates; Bacillus megaterium; Esters; Lipase; Oxidoreductases; Phthalic Acids; Polyenes; Polyesters; Polymers; Pseudomonas mendocina; Pseudomonas oleovorans; Pseudomonas pseudoalcaligenes; Soil
PubMed: 35850225
DOI: 10.1016/j.chemosphere.2022.135700 -
MicroPublication Biology 2022experiences and microbiome have been shown to shape its responses to certain stimuli; a recent study found that grown on JUb39 exhibited increased attraction to that...
experiences and microbiome have been shown to shape its responses to certain stimuli; a recent study found that grown on JUb39 exhibited increased attraction to that same growth bacteria while also lowered repulsion to the odor 1-octanol (O’Donnell et al. 2020). This prompted us to ask whether other strains of bacteria could likewise alter responses to bacterial food and volatile chemicals. So, to expand upon current knowledge, we cultured wild-type (N2) on an unidentified ( sp?), (MSPm1), (MYb11), (JUb19), or strain ( sp?). After several generations, we examined how their choice of bacterial food was affected. In addition, we looked at their response to the olfactory stimuli 2-butanone; 2,3-butanedione; 2,3-pentanedione; and 2-nonanone, as well as their response to the gustatory stimulus sodium chloride. Interestingly, we found that growth on any of these bacterial strains led to their bacterial preferences and behavioral responses to 2-butanone; 2,3-pentanedione; diacetyl; and sodium chloride remaining unchanged. However, we also saw that showed a preference for MSPm1 and sp? to HB101, and HB101 to MYb11. Furthermore, worms that are grown on MSPm1 showed stronger attraction to a 1:10 dilution of 2-nonanone (AWB-sensed odorant) as compared to worms grown on the other bacterial strains.
PubMed: 35622520
DOI: 10.17912/micropub.biology.000535 -
Cureus Mar 2022is a Gram-negative bacillus from the family Pseudomonadaceae. The first -related infection was reported in 1992. Although a rare cause of infections, has been known...
is a Gram-negative bacillus from the family Pseudomonadaceae. The first -related infection was reported in 1992. Although a rare cause of infections, has been known to cause severe infections that require intensive treatment. We present the first documented case of urinary tract infection caused by An 83-year-old male with a past medical history of diabetes, hypertension, coronary artery disease, and prostate cancer with bone metastases, currently being treated with abiraterone and prednisone, presented with subjective fever, fatigue, altered mental status, dysuria, and hematuria of one-week duration. He was found to have a complicated urinary tract infection with an incidental asymptomatic COVID-19 infection on admission. The patient was empirically treated with ceftriaxone and switched to cefepime for broader coverage on day two of hospitalization. Urine culture reported the presence of with resistance only to fluoroquinolones. Ceftriaxone was reinstated. The patient was successfully treated with a seven-day course of ceftriaxone (days 1-3, days 6-7) and cefepime (days 4-5) but continued to remain inpatient for a later symptomatic COVID-19 pneumonia with discharge on day 15. The majority of . infections present as skin and soft tissue infections, infective endocarditis, meningitis, and bacteremia. Ours is the first documented case of urinary tract infection caused by particularly in an immunocompromised COVID-19 patient, and the second to report with resistance to fluoroquinolones. This report contributes to the growing literature regarding -related infections.
PubMed: 35495004
DOI: 10.7759/cureus.23583 -
Metabolic Engineering Jul 2022The objective of this study was to implement direct sunlight-driven conversion of CO into a naturally excreted ready-to-use fuel. We engineered four different synthetic...
The objective of this study was to implement direct sunlight-driven conversion of CO into a naturally excreted ready-to-use fuel. We engineered four different synthetic metabolic modules for biosynthesis of short-to medium-chain length hydrocarbons in the model cyanobacterium Synechocystis sp. PCC 6803. In module 1, the combination of a truncated clostridial n-butanol pathway with over-expression of the native cyanobacterial aldehyde deformylating oxygenase resulted in small quantities of propane when cultured under closed conditions. Direct conversion of CO into propane was only observed in strains with CRISPRi-mediated repression of three native putative aldehyde reductases. In module 2, three different pathways towards pentane were evaluated based on the polyunsaturated fatty acid linoleic acid as an intermediate. Through combinatorial evaluation of reaction ingredients, it was concluded that linoleic acid undergoes a spontaneous non-enzymatic reaction to yield pentane and hexanal. When Synechocystis was added to the reaction, hexanal was converted into 1-hexanol, but there was no further stimulation of pentane biosynthesis even in the Synechocystis strains expressing GmLOX1. For modules 3 and 4, several different acyl-ACP thioesterases were evaluated in combination with two different decarboxylases. Small quantities of 1-heptene and 1-nonene were observed in strains expressing the desaturase-like enzyme UndB from Pseudomonas mendocina in combination with C8-C10 preferring thioesterases ('CaFatB3.5 and 'ChoFatB2.2). When UndB instead was combined with a C12-specific 'UcFatB1 thioesterase, this resulted in a ten-fold increase of alkene biosynthesis. When UndB was replaced with the light-dependent FAP decarboxylase, both undecane and tridecane accumulated, albeit with a 10-fold drop in productivity. Preliminary optimization of the RBS, promoter and gene order in some of the synthetic operons resulted in improved 1-alkene productivity, reaching a titer of 230 mg/L after 10 d with 15% carbon partitioning. In conclusion, the direct bioconversion of CO into secreted and ready-to-use hydrocarbon fuel was implemented with several different metabolic systems. Optimal productivity was observed with UndB and a C12 chain-length specific thioesterase, although further optimization of the entire biosynthetic system is still possible.
Topics: Aldehydes; Alkenes; Carbon Dioxide; Hydrocarbons; Linoleic Acid; Metabolic Engineering; Metabolic Networks and Pathways; Pentanes; Propane; Synechocystis
PubMed: 35134557
DOI: 10.1016/j.ymben.2022.01.017 -
Current Microbiology Jan 2022An arsenic resistant bacteria SMSKVR-3 has been isolated from the rhizospheric soil of the metal-contaminated site of khetri copper mines situated in the Jhunjhunu...
An arsenic resistant bacteria SMSKVR-3 has been isolated from the rhizospheric soil of the metal-contaminated site of khetri copper mines situated in the Jhunjhunu district of Rajasthan, India. The strain showed homology with Pseudomonas mendocina strain ATCC 25411. This gram-negative isolate exhibited optimal growth in M9 minimal media with temperature and salt concentration as 30 °C and 0.25% (w/v), respectively, at pH 7.0. The similar growth pattern and SEM analysis of this strain exposed to M9 minimal media alone, M9 media supplemented with 300 mM arsenate [As(V)] or M9 media supplemented with 1.34 mM arsenite [As(III)] indicate the existence of the strong arsenic resistance mechanism. The isolate was able to produce siderophores and was able to reduce As(V) to As(III). A decrease in polyP concentration from 354.8 µg/10 CFU mL at 0 h to 0.043 µg/10 CFU mL at 8 h incubation with As(V) was in correlation with the change in intracellular As(V) concentration (116.98 mg L/10 cells at 0 h to 88.65 mg L/10 at 8 h) with time. This shows the possible role of polyP bodies in the regulation of As(V) concentration inside the cell. The presence of arsC gene in P.mendocina SMSKVR-3 was confirmed by the PCR amplification of arsC gene. The BLAST analysis of the sequenced gene represented 98.59% identity with the P. mendocina S5.2 arsenate reductase. These results indicate that the observed arsenic resistance in SMSKVR-3 is due to a combination of siderophore production, the transformation of As(V) to As(III) by arsenate reductase, multi-drug efflux pump, and polyP bodies mediated metal resistance mechanism.
Topics: Arsenic; Copper; India; Pseudomonas mendocina; Siderophores
PubMed: 35059829
DOI: 10.1007/s00284-021-02749-6 -
Bioresource Technology Feb 2022Two biosafety strains, identified as Pseudomonas mendocina S16 and Enterobacter cloacae DS'5, were isolated from freshwater aquaculture ponds and showed significant...
Nitrogen removal characteristics and potential application of the heterotrophic nitrifying-aerobic denitrifying bacteria Pseudomonas mendocina S16 and Enterobacter cloacae DS'5 isolated from aquaculture wastewater ponds.
Two biosafety strains, identified as Pseudomonas mendocina S16 and Enterobacter cloacae DS'5, were isolated from freshwater aquaculture ponds and showed significant heterotrophic nitrification-aerobic denitrification abilities. Within 48 h, the inorganic nitrogen removal efficiencies in the two strains were 66.59 %-97.97 % (S16) and 72.27 %-96.44 % (DS'5). The optimal conditions for organic nitrogen removal of the two strains were temperature 20-35 °C and carbon/nitrogen (C/N) ratio 10-20 while using sodium citrate as the carbon source. Sequence amplification demonstrated the presence of the denitrification genes in both the two strains, and quantitative real-time PCR results showed that the coupled expression of nap + nar would improve the nitrate removal rate in S16. The nitrogen removal efficiencies of the two strains in immobilization culture systems were 79.80 %-98.58 % (S16) and 60.80 %-98.40 % (DS'5). This study indicated the great potential application of the two strains in aquaculture tail water treatment.
Topics: Aerobiosis; Aquaculture; Bacteria; Denitrification; Enterobacter cloacae; Heterotrophic Processes; Nitrification; Nitrites; Nitrogen; Ponds; Pseudomonas mendocina; Wastewater
PubMed: 34910970
DOI: 10.1016/j.biortech.2021.126541