62 research outputs found
Facilitation of co-metabolic transformation and degradation of monochlorophenols by Pseudomonas sp. CF600 and changes in its fatty acid composition
In this study, co-metabolic degradation of monochlorophenols (2-CP, 3-CP, and 4-CP) by the Pseudomonas sp. CF600 strain in the presence of phenol, sodium benzoate, and 4-hydroxybenzoic acid as an additional carbon source as well as the survival of bacteria were investigated. Moreover, the changes in cellular fatty acid profiles of bacteria depending on co-metabolic conditions were analyzed. It was found that bacteria were capable of degrading 4-CP completely in the presence of phenol, and in the presence of all substrates, they degraded 2-CP and 3-CP partially. The highest 2-CP and 3-CP removal was observed in the presence of sodium benzoate. Bacteria exhibited three various dioxygenases depending on the type of growth substrate. It was also demonstrated that bacteria exposed to aromatic growth substrates earlier degraded monochlorophenols more effectively than unexposed cells. The analysis of fatty acid profiles of bacteria indicated the essential changes in their composition, involving alterations in fatty acid saturation, hydroxylation, and cyclopropane ring formation. The most significant change in bacteria exposed to sodium benzoate and degrading monochlophenols was the appearance of branched fatty acids. The knowledge from this study indicates that Pseudomonas sp. CF600 could be a suitable candidate for the bioaugmentation of environments contaminated with phenolic compounds
Still Seeking for Something : The Unspeakable (Loss) in Passing by Nella Larsen
The paper analyzes Nella Larsen’s Passing (1929) through the lens of the theory of melancholy from Freud to Butler. Examining the dynamic relationship between Irene Redfield and Clare Kendry, two protagonists of Larsen’s novella, I attempt to demonstrate that under the surface of clearly expressed racial tensions, focused upon the dilemma of passing, there is a more deeply hidden problem - the one of gender identity and sexual desire
“An Unexpectedly Transgressive Subject of Twentieth-Century History”: How to Write (and Why to Read) about Communist Women Today
This review article discusses two newly-released publications on communist women activists: Kristen Ghodsee’s Red Valkyries: Feminist Lessons from Five Revolutionary Women and The Palgrave Handbook of Communist Women Activists around the World, edited by Francisca de Haan. It focuses on questions of narrative and the persuasive function of the reviewed works, asking how and for whom one should write about communist women today. It brings to light methodological challenges, as well as those related to access to sources on communist women. It also reflects on the place that publications which tell stories of communist women who challenged gender, class, and racial inequalities in the past occupy in the perception of contemporary readers, so often confronted in these times with experiences of inequality and violence
Changes in fatty acid composition of Stenotrophomonas maltophilia KB2 during co-metabolic degradation of monochlorophenols
The changes in the cellular fatty acid composition of Stenotrophomonas maltophilia KB2 during cometabolic degradation of monochlorophenols in the presence of phenol as well as its adaptive mechanisms to these
compounds were studied. It was found that bacteria were capable of degrading 4-chlorophenol (4-CP) completely in the presence of phenol, while 2-chlorophenol (2-CP) and 3-chlorophenol (3-CP) they degraded partially. The analysis of the fatty acid profiles indicated that adaptive mechanisms of bacteria depended on earlier exposure to phenol, which isomer they degraded, and on incubation time. In bacteria unexposed to phenol the permeability and structure of their membranes could be modified through the increase of hydroxylated and cyclopropane fatty acids, and straight-chain and hydroxylated fatty acids under 2-CP,
3-CP and 4-CP exposure, respectively. In the exposed cells, regardless of the isomer they degraded, the most important changes were connected with the increase of the contribution of branched fatty acid on day 4 and the content of hydroxylated fatty acids on day 7. The changes, particularly in the proportion of branched fatty acids, could be a good indicator for assessing the progress of the degradation of monochlorophenols by S. maltophilia KB2. In comparison, in phenol-degrading cells the increase of cyclopropane and straight-chain fatty acid content was established. These findings indicated the degradative potential of the tested strain towards the co-metabolic degradation of persistent chlorophenols, and extended the current knowledge about the adaptive mechanisms of these bacteria to such chemicals
Transformation and ecotoxicological effects of iodinated X-ray contrast media
Iodinated X-ray contrast media (ICM)
such as diatrizoate, iohexol, iomeprol, iopamidol,
and iopromide are commonly used in medical imaging
for radiological visualization of a variety of anatomic
structures. Because of their highly persistent nature
and poor removal by conventional wastewater treatment,
ICM can often remain unchanged after entering
the environment or they are transformed into many
different by-products in complex physical, chemical,
and biological processes. Large amounts of ICM and
their by-products are found in natural waters, groundwater,
drinking water (up to 100 lg/L), and even in
soil, where they can be a potential threat to the
inhabitants of these environments. Because knowledge
about the fate of ICM in various environments is
dispersed and it concerns specific areas, the main
purpose of this review is to summarize the available
information about their occurrence, chemical and
biological transformation/degradation, and toxicity to
living organisms. The topics discussed particularly
focus on mechanisms of ICM degradation/transformation
in water using advanced oxidation processes
and the biotransformation/biodegradation of ICM by
microorganisms under different conditions, as well as
the toxicity of ICM and their transformation byproducts
to humans and other organisms. Although
environmental risk is not expected from the parent
compounds of ICM, their continuous input to the water
and the formation of toxic by-products may constitute
a long-term potential risk for living organisms.
Therefore, monitoring the transport and fate of ICM
in various environments seems necessary
„Komuniści (nie) mają ojczyzny...” Wanda Wasilewska jako polska (anty)bohaterka narodowa
Communists have no homeland: a portrait of Wanda Wasilewska
The paper offers an analysis of a number of biographies of Wanda Wasilewska, written in different historical periods. An attempt was made to reconstruct the mechanisms that governed the functioning of Wanda Wasilewska’s communist figure in the Polish political discourse; explain how she was perceived by the society, and how it altered in the course of the Polish cultural and historical transformations. A biography of an individual gains coherence as a result of the community’s search for its identity: it serves as a building block for a coherent biography of the entire community. The writing and rewriting of the biography of Wasilewska has long been a kind of “production of communism” in Poland, and communism has been one of the most important aspects of Polish identity in the recent decades.
„Komuniści (nie) mają ojczyzny...” Wanda Wasilewska jako polska (anty)bohaterka narodowa
Autorka analizuje powstające w rożnych okresach historycznych biografie Wandy Wasilewskiej. Usiłuje odtworzyć mechanizmy konstruowania figury komunistki w polskim dyskursie publicznym, zbadać, jak funkcjonowała ona w społecznym odbiorze, a także ustalić, jak zmieniało się jej znaczenie w procesie przemian historycznych i kulturowych. Autorka pokazuje, że tworzenie spójnej biografii jednostki – szczególnie jednostki ważnej w historii danej zbiorowości – dokonuje się w odpowiedzi na tożsamościowe poszukiwania wspólnoty: służy wytworzeniu zbiorowej biografii jako koherentnej całości. Zwraca uwagę, że pisanie biografii Wasilewskiej jako komunistki było i wciąż jest swoistym „wytwarzaniem komunizmu” w Polsce. Komunizm zaś w szerokim planie jest ważnym – jeśli nie najważniejszym w ostatnich dziesięcioleciach – komponentem polskiej zbiorowej tożsamości
Microbial action in wastewater and sludge
This Special Issue provides valuable results and new views on the topic of pollutant removal from wastewater and landfill leachate based on various remediation approaches and literature data, including important key challenges and limitations. The novelties worth emphasizing are: the proposition of ideal candidates for bioaugmentation of activated sludge fed with phenolic leachate; the isolation and identification of new diclofenac-degrading strains; the first use of active biomass and stress biomass indices to assess the impact of leachate and bioaugmentation on AS performance; the use of Ascomycete Lambertella sp. in the depletion of the recalcitrant to biodegradation loads of intermediate and old leachate; as well as an interesting presentation of scientific views on pollutant biosorption using fungal pellets. All authors also emphasized the need for further research and indicated future study directions
Zmiany w składzie bakteryjnych kwasów tłuszczowych w czasie rozkładu fenolu w glebie
The aim of this study was to investigate the effects of
phenol on fatty acid composition of Pseudomonas
vesicularis and Pseudomonas sp. JS150 strains introduced
into sterile L1, L2 and G soils and in Pseudomonas-
inoculated non-sterile soils. Phenol was added to all
soils at the concentration of 1.7 mg g–1, 3.3 mg g–1 and
5.0 mg g–1. Simultaneously, the survival of both strains
introduced into soils was estimated. The investigations
were conducted in four separate experimental arrangements.
The first comprised sterile soils with introduced
Pseudomonas vesicularis strain, the second — sterile
soils with Pseudomonas sp. JS150, the third-sterile soils
containing the mixture of these strains and the fourth —
Pseudomonas-inoculated non-sterile soils. FAMEs extracted
from these soils at the following sampling days
were analysed by GC method and identified using software
Sherlock, 3,90.
It was found that phenol degradation by Pseudomonas
vesicularis or/and Pseudomonas sp. JS150 depended
on type of soil, phenol contamination and inoculum
composition. The highest phenol removal at each concentration
in L1, L2 and G soils was observed when
bacteria were used as a mixture, phenol was metabolized
slower by Pseudomonas sp. JS150 and much
slower by Pseudomonas vesicularis. It was also demonstrated
that independently on inoculum composition
phenol degradation rate varied depending on type of
soil. In G soil with the highest amount of organic matter
phenol degradation proceeded faster than in L1 soil with
intermediate amount of organic matter and in L2 soil
with the lowest amount of organic matter. Obtained results
also indicated that increasing dose of phenol made
its biodegradation much longer. On the basis of bacterial
counts it was showed that Pseudomonas sp. JS150
strain better survived both in phenol-polluted and the
unpolluted soils in comparison with Pseudomonas
vesicularis. Bioaugmentation with Pseudomonas
vesicularis and Pseudomonas sp. JS150 strain in all
soils resulted in the increase of effectiveness of phenol
removal as compared to control samples. It indicated
that the interactions between autochtonous bacteria and
strains introduced into soils were synergic.
The analyses of fatty acid percentages and composition
in bacterial cells showed that they regulated of
membrane fluidity and permeability in response to actual phenol concentration in soil. The first reaction of
both strains in the presence of phenol added was de
novo synthesis and changes in composition of saturated,
straight-chain and branched fatty acids at the beginning
days of experiment. While the phenol concentration decreased
above 50% of dose used cyclopropane fatty acid
19:0 cy ω10c from these cells was isolated. In turn, the
abundance of hydroxy fatty acids in that time decreased
or they were not present in FAMEs profiles. The ratio
of saturated/unsaturated fatty acids appeared the useful
marker for rate of phenol degradation by Pseudomonas
vesicularis or/and Pseudomonas sp. JS150. At the first
days of experiment when phenol concentration in soils
was high saturated/unsaturated ratio increased. It highest
value was calculated generally at day when the abundance
of 19:0 cy ω10c fatty acid was the highest
whereas at the following days simultaneously with phenol
removal it decreased. The value of sat/unsat ratio
varied in response to the type of soil, inoculum composition
and dose of phenol added. The similar correlations
between phenol concentration, the presence of
19:0 cy ω10c fatty acid and value of sat/unsat ratio were
observed in phenol amended and Pseudomonas-inoculated
soils and phenol amended but not-inoculated soils.
The abundance of saturated, straight-chain and branched
fatty acids changed also in these soils but the changes
were significantly lower as compared to sterile soils
with introduced of Pseudomonas vesicularis or/and
Pseudomonas sp. JS150 strains. In turn, the amount of
hydroxy fatty acids isolated from these soils remained at
the similar level. It indicates that adaptive mechanisms
to the presence of phenol were similar both in laboratory
selective of Pseudomonas vesicularis and Pseudomonas
sp. JS150 strains and in other species of bacteria
naturally existing in soil.
It was confirmed that MIDI-FAME method could be
used to monitor the progress of phenol elimination from
soil. On the basis of fatty acid profiles and analysis of
value of sat/unsat ratio it is possible to estimate if degradation
of phenol by microorganisms in soil proceeds
and the presence and abundance of 19:0 cy ω10c fatty
acid indicate the progress of this process. For this reason,
they may be good biomarkers of phenol contaminated
environments
Materijalno-energetski model životnog ciklusa motornog vozila
Nowadays one of the most important elements of economic and social lives is motorization. Its development is most of all accompanied by increasing the use of various means of transport, especially motor vehicles. Such a significant increase in the amount of vehicles produced can be implemented by the global use of productive materials and energy carriers, which is increasingly higher each year. Operating a higher number of vehicles causes an increase in environment pollution, not only by deleterious substance emissions, being the effect of fuel combustion, or implementation of production processes in the automotive industry, but also by a growing amount of exchanged parts and sub-assemblies and, mostly, by the rapid growth of vehicles that are withdrawn from traffic and subjected to car breaking.
The article presents a material-energy model of a motor car life cycle that can be helpful in determining the type and size of the expenditure of material and energy as well as emission loading in particular phases and the whole life cycle of a vehicle. Based on the input data contained in [9] analysis of the results of calculations related to examples of the material structure of the model vehicle from 1990 and 2000 and the impact of these changes on energy consumption and emission levels were presented.Jedan od najvažnijih elemenata ekonomskog i društvenog života u današnje vrijeme je motorizacija. Njen razvoj je u najvećoj mjeri popraćen povećanim uporabom prijevoznih sredstava, posebice motornih vozila. Takvo značajno povećanje količine proizvedenih vozila provodi se zbog globalne uporabe proizvodnih materijala i nositelja energije iz godine u godinu je sve veća i veća. Veći broj vozila u pogonu povećava zagađenje okoliša, ne samo emisijama štetnih tvari u okoliš, koje su posljedica izgaranja goriva, ili izvođenje procesa proizvodnje u automobilskoj industriji, već i zbog porasta količine promjenljivih dijelova i podsklopova, a ponajviše zbog ubrzanog rasta broja vozila koja se povuku iz prometa i rastavljaju.
Članak predstavlja materijalno-energetski model životnog vijeka motornog vozila koji uvelike može pomoći prilikom određivanja vrste i veličine troškova materijala i energije, kao i ispuštanja emisija u određenim fazama i cjelokupnog životnog vijeka vozila. Na temelju ulaznih podataka koji se nalaze u [9] predstavljena je analiza rezultata proračuna koji se odnosi na primjere strukture materijala modela vozila od 1990. i 2000. i utjecaja na promjene u potrošnji energije i emisiji štetnih plinova
- …