Two fosmid libraries, totaling 13,200 clones, were obtained from bioreactor sludge of petroleum refinery wastewater treatment system. The library screening based on PCR and biological activity assays ...revealed more than 400 positive clones for phenol degradation. From these, 100 clones were randomly selected for pyrosequencing in order to evaluate the genetic potential of the microorganisms present in wastewater treatment plant for biodegradation, focusing mainly on novel genes and pathways of phenol and aromatic compound degradation. The sequence analysis of selected clones yielded 129,635 reads at an estimated 17-fold coverage. The phylogenetic analysis showed Burkholderiales and Rhodocyclales as the most abundant orders among the selected fosmid clones. The MG-RAST analysis revealed a broad metabolic profile with important functions for wastewater treatment, including metabolism of aromatic compounds, nitrogen, sulphur and phosphorus. The predicted 2,276 proteins included phenol hydroxylases and cathecol 2,3- dioxygenases, involved in the catabolism of aromatic compounds, such as phenol, byphenol, benzoate and phenylpropanoid. The sequencing of one fosmid insert of 33 kb unraveled the gene that permitted the host, Escherichia coli EPI300, to grow in the presence of aromatic compounds. Additionally, the comparison of the whole fosmid sequence against bacterial genomes deposited in GenBank showed that about 90% of sequence showed no identity to known sequences of Proteobacteria deposited in the NCBI database. This study surveyed the functional potential of fosmid clones for aromatic compound degradation and contributed to our knowledge of the biodegradative capacity and pathways of microbial assemblages present in refinery wastewater treatment system.
Water generated during oil exploration is chemically complex and contains high concentrations of ammonium and, in some cases, high salinity. The most common way to remove ammonium from effluent is a ...biological process, which can be performed by different routes and different groups of microorganisms. However, the presence of salts in the effluents could be an inhibiting factor for biological processes, interfering directly with treatment. This study aimed to evaluate changes in the profile of a microbial community involved in the process of ammonium removal when subjected to a gradual increase of salt (NaCl), in which the complete inhibition of the ammonium removal process occurred at 125 g L
−1
NaCl. During the sludge acclimatization process, samples were collected and submitted to denaturing gradient gel electrophoresis (DGGE) and massive sequencing of the 16S ribosomal RNA (rRNA) genes. As the salt concentration increased in the reactor, a change in the microbial community was observed by the DGGE band profiles. As a result, there was a reduction in the presence of bacterial populations, and an increase in archaeal populations was found. The sequencing data suggested that ammonium removal in the reactor was carried out by different metabolic routes by autotrophic nitrifying bacteria, such as
Nitrosococcus
,
Nitrosomonas
,
Nitrosovibrio
,
Nitrospira
, and
Nitrococcus
; ammonium-oxidizing archaea
Candidatus nitrosoarchaeum
; ANAMMOX microorganisms, such as
Candidatus brocadia, Candidatus kuenenia
, and
Candidatus scalindua
; and microorganisms with the potential to be heterotrophic nitrifying, such as
Paracoccus
spp.,
Pseudomonas
spp.,
Bacillus
spp.,
Marinobacter
sp., and
Alcaligenes
spp.
The vomeronasal system (VNS) has been extensively studied within specific animal families, such as Rodentia. However, the study of the VNS in other families, such as Canidae, has long been neglected. ...Among canids, the vomeronasal organ (VNO) has only been studied in detail in the dog, and no studies have examined the morphofunctional or immunohistochemical characteristics of the VNS in wild canids, which is surprising, given the well‐known importance of chemical senses for the dog and fox and the likelihood that the VNS plays roles in the socio‐reproductive physiology and behaviours of these species. In addition, characterising the fox VNS could contribute to a better understanding of the domestication process that occurred in the dog, as the fox would represent the first wild canid to be studied in depth. Therefore, the aim of this study was to analyze the morphological and immunohistochemical characteristics of the fox VNO. Tissue dissection and microdissection techniques were employed, followed by general and specific histological staining techniques, including with immunohistochemical and lectin‐histochemical labelling strategies, using antibodies against olfactory marker protein (OMP), growth‐associated protein 43 (GAP‐43), calbindin (CB), calretinin (CR), α‐tubulin, Gαo, and Gαi2 proteins, to highlight the specific features of the VNO in the fox. This study found significant differences in the VNS between the fox and the dog, particularly concerning the expression of Gαi2 and Gαo proteins, which were associated with the expression of the type 1 vomeronasal receptors (V1R) and type 2 vomeronasal receptors (V2R), respectively, in the vomeronasal epithelium. Both are immunopositive in foxes, as opposed to the dog, which only expresses Gαi2. This finding suggests that the fox possesses a well‐developed VNO and supports the hypothesis that a profound transformation in the VNS is associated with domestication in the canid family. Furthermore, the unique features identified in the fox VNO confirm the necessity of studying the VNS system in different species to better comprehend specific phylogenetic aspects of the VNS.
We present the first morphofunctional study of the vomeronasal organ of a wild canid, the red fox, which highlights the importance of chemical communication in this species and opens a new perspective on the canid vomeronasal system.
•The fox accessory olfactory bulb (AOB) possesses a higher degree of morphological development compared with the dog AOB.•A decrease in the anatomical complexity of the accessory olfactory system ...occurred during the evolutionary history of dogs.•The structural differences observed between the dog and the fox accessoryolfactory bulbs may be the result of domestication.•The lack of Gao afferences to the AOB suggests a direct pathway from the vomeronasal organ to the main olfactory bulb.
The accessory olfactory bulb (AOB) is the first integrative center of the vomeronasal system (VNS), and the general macroscopic, microscopic, and neurochemical organizational patterns of the AOB differ fundamentally among species. Therefore, the low degree of differentiation observed for the dog AOB is surprising. As the artificial selection pressure exerted on domestic dogs has been suggested to play a key role in the involution of the dog VNS, a wild canid, such as the fox, represents a useful model for studying the hypothetical effects of domestication on the AOB morphology.
A comprehensive histological, lectin-histochemical, and immunohistochemical study of the fox AOB was performed. Anti-Gαo and anti-Gαi2 antibodies were particularly useful, as they label the transduction cascade of the vomeronasal receptor types 1 (V1R) and 2 (V2R), respectively. Other employed antibodies included those against proteins such as microtubule-associated protein 2 (MAP-2), tubulin, glial fibrillary acidic protein, growth-associated protein 43 (GAP-43), olfactory marker protein (OMP), calbindin, and calretinin.
The cytoarchitecture of the fox AOB showed a clear lamination, with neatly differentiated layers; a highly developed glomerular layer, rich in periglomerular cells; and large inner cell and granular layers. The immunolabeling of Gαi2, OMP, and GAP-43 delineated the outer layers, whereas Gαo and MAP-2 immunolabeling defined the inner layers. MAP-2 characterized the somas of AOB principal cells and their dendritic trees. Anti-calbindin and anti-calretinin antibodies discriminated neural subpopulations in both the mitral-plexiform layer and the granular cell layer, and the lectin Ulex europeus agglutinin I (UEA-I) showed selectivity for the AOB and the vomeronasal nerves.
The fox AOB presents unique characteristics and a higher degree of morphological development compared with the dog AOB. The comparatively complex neural basis for semiochemical information processing in the fox compared with that observed in dogs suggests loss of AOB anatomical complexity during the evolutionary history of dogs and opens a new avenue of research for studying the effects of domestication on brain structures.
In petrochemical refinery wastewater treatment plants (WWTP), different concentrations of pollutant compounds are received daily in the influent stream, including significant amounts of phenolic ...compounds, creating propitious conditions for the development of particular microorganisms that can rapidly adapt to such environment. In the present work, the microbial sludge from a refinery WWTP was enriched for phenol, cloned into fosmid vectors and pyrosequenced. The fosmid libraries yielded 13,200 clones and a comprehensive bioinformatic analysis of the sequence data set revealed a complex and diverse bacterial community in the phenol degrading sludge. The phylogenetic analyses using MEGAN in combination with RDP classifier showed a massive predominance of Proteobacteria, represented mostly by the genera
Diaphorobacter, Pseudomonas, Thauera
and
Comamonas
. The functional classification of phenol degrading sludge sequence data set generated by MG-RAST showed the wide metabolic diversity of the microbial sludge, with a high percentage of genes involved in the aerobic and anaerobic degradation of phenol and derivatives. In addition, genes related to the metabolism of many other organic and xenobiotic compounds, such as toluene, biphenyl, naphthalene and benzoate, were found. Results gathered herein demonstrated that the phenol degrading sludge has complex phylogenetic and functional diversities, showing the potential of such community to degrade several pollutant compounds. This microbiota is likely to represent a rich resource of versatile and unknown enzymes which may be exploited for biotechnological processes such as bioremediation.
Oil refineries are known for the large volume of water used in their processes, as well as the amount of wastewater generated at the end of the production chain. Due to strict environmental ...regulations, the recycling of water has now become a viable alternative for refineries. Among the many methods available to treat wastewater for reuse, the use of membranes in reverse osmosis systems stands out due to several economic and environmental benefits. However, these systems are vulnerable to contamination and deposition of microorganisms, mainly because of the feedwater quality. In this study, the microbial diversity of feedwater and reverse osmosis membranes was investigated using a combination of culture-dependent and culture-independent methods in order to characterize the microorganisms colonizing and deteriorating the membranes. In total, 37 bacterial isolates, 17 filamentous fungi and approximately 400 clones were obtained and analyzed. Among the bacterial genera identified, the most represented were Sphingobium, Acidovorax, Microbacterium, Rhizobium and Shinella. The results revealed genera that acted as candidate key players in initial biofilm formation in membrane systems, and provided important information concerning the microbial ecology of oligotrophic aquatic systems.
The treatment of a refinery wastewater (oily stream) was investigated using a submerged membrane bioreactor (SMBR) operating with constant permeate flux. During the operation, long-term high organic ...loading rates were applied in the SMBR by feeding blends of the oily stream with a high strength phenolic wastewater, also generated in petroleum refineries. The effects of high organic loadings were evaluated regarding the organic matter and phenols removal efficiencies. The influence of the loading rate on filtration was also assessed, including the effects on the production of soluble microbial products, namely polysaccharides and proteins, and retention of these compounds by the membrane. The membrane had a key role in the process, since it improved COD and TOC removal efficiencies by 17 and 20%, respectively. The results proved the ability of the SMBR to tackle with high strength feed during long-term exposition achieving high phenols removal efficiencies, even with such complex feed.
The phenolic compounds are a major contaminant class often found in industrial wastewaters and the biological treatment is an alternative tool commonly employed for their removal. In this sense, ...monitoring microbial community dynamics is crucial for a successful wastewater treatment. This work aimed to monitor the structure and activity of the bacterial community during the operation of a laboratory-scale continuous submerged membrane bioreactor (SMBR), using PCR and RT-PCR followed by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA libraries. Multivariate analyses carried out using DGGE profiles showed significant changes in the total and active dominant community members during the 4-week treatment period, explained mainly by phenol and ammonium input. Gene libraries were assembled using 16S rDNA and 16S rRNA PCR products from the fourth week of treatment. Sequencing and phylogenetic analyses of clones from the 16S rDNA library revealed a high diversity of taxa for the total bacterial community, with predominance of Thauera genus (ca. 50%). On the other hand, a lower diversity was found for metabolically active bacteria, which were mostly represented by members of Betaproteobacteria (Thauera and Comamonas), suggesting that these groups have a relevant role in the phenol degradation during the final phase of the SMBR operation.
Anaerobic digestion is a widely used effluent and organic waste treatment practice, in which it is possible to minimize and control environmental problems, associating the reduction of environmental ...impacts with energy recovery. Low methane production and process instability are often found in anaerobic digestion reactors, preventing this technique from being widely applied. Inhibitory substances, such as sulfides resulting from sulfate conversion by the sulfur reducing bacteria, are one of the causes of inhibition or malfunctioning of anaerobic digesters if they are present in the effluent to be treated. The objective of this work is to evaluate the effect of sulfide at two different values of pH (7.0 and 7.5) using sulfide concentrations of 0 to 1000 mg S2-L-1. All the tests were performed in batches and performed at mesophilic conditions. For the concentrations of 50 mg S2-L-1 and 1000 mg S2-L-1, the inhibitions of the methanogenic activity at pH 7.0 were in the order of 38.5% to 59.8% and at pH 7.5 in the order of 67% to 94%, respectively. Concerning the test at pH 7.0, the removal of COD in the experiment without addition of any concentration of S2- was 93.3%, and it reached a 49.14% COD removal at concentrations of 1000 mg S2-L-1. At pH 7.5 under the same conditions, the COD removals were respectively 80.7% and 9.6%. The concentrations of 50, 75 and 100 mg S2-L-1 of S2- initially tested at the two aforementioned pH values promoted the greatest increase in the reduction of SMA. When the experiments were carried out at pH 7.0 the reductions were 37.96%, 41.70%, and 46.06% respectively for the same concentrations. At pH 7.5 the reductions represented 67.01%, 82.47% and 81.81%. http://dx.doi.org/10.18226/23185279.v6iss2p1
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