Microbial-based evaluation of foaming events in full-scale wastewater treatment plants by microscopy survey and quantitative image analysis

Activated sludge systems are prone to be affected by foaming occurrences causing the sludge to rise in the reactor and affecting the wastewater treatment plant (WWTP) performance. Nonetheless, there is currently a knowledge gap hindering the development of foaming events prediction tools that may be fulfilled by the quantitative monitoring of AS systems biota and sludge characteristics. As such, the present study focuses on the assessment of foaming events in full-scale WWTPs, by quantitative protozoa, metazoa, filamentous bacteria, and sludge characteristics analysis, further used to enlighten the inner relationships between these parameters. In the current study, a conventional activated sludge system (CAS) and an oxidation ditch (OD) were surveyed throughout a period of 2 and 3 months, respectively, regarding their biota and sludge characteristics. The biota community was monitored by microscopic observation, and a new filamentous bacteria index was developed to quantify their occurrence. Sludge characteristics (aggregated and filamentous biomass contents and aggregate size) were determined by quantitative image analysis (QIA). The obtained data was then processed by principal components analysis (PCA), cross-correlation analysis, and decision trees to assess the foaming occurrences, and enlighten the inner relationships. It was found that such events were best assessed by the combined use of the relative abundance of testate amoeba and nocardioform filamentous index, presenting a 92.9 % success rate for overall foaming events, and 87.5 and 100 %, respectively, for persistent and mild events

Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-induced tautomerization in argon matrix

The prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol−1 ; Gibbs free energy difference: 9.8 kJ mol−1 ). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction.UI0313B/QUI/2020, UI0313P/QUI/2020info:eu-repo/semantics/publishedVersio

In vitro assessment of antimicrobial, antioxidant, and cytotoxic properties of Saccharin-Tetrazolyl and-Thiadiazolyl derivatives: the simple dependence of the pH value on antimicrobial activity

The antimicrobial, antioxidant, and cytotoxic activities of a series of saccharin-tetrazolyl and -thiadiazolyl analogs were examined. The assessment of the antimicrobial properties of the referred-to molecules was completed through an evaluation of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against Gram-positive and Gram-negative bacteria and yeasts. Scrutiny of the MIC and MBC values of the compounds at pH 4.0, 7.0, and 9.0 against four Gram-positive strains revealed high values for both the MIC and MBC at pH 4.0 (ranging from 0.98 to 125 µg/mL) and moderate values at pH 7.0 and 9.0, exposing strong antimicrobial activities in an acidic medium. An antioxidant activity analysis of the molecules was performed by using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, which showed high activity for the TSMT (N-(1-methyl-2H-tetrazol-5-yl)-N-(1,1-dioxo-1,2-benzisothiazol-3-yl) amine, 7) derivative (90.29% compared to a butylated hydroxytoluene positive control of 61.96%). Besides, the general toxicity of the saccharin analogs was evaluated in an Artemia salina model, which displayed insignificant toxicity values. In turn, upon an assessment of cell viability, all of the compounds were found to be nontoxic in range concentrations of 0-100 µg/mL in H7PX glioma cells. The tested molecules have inspiring antimicrobial and antioxidant properties that represent potential core structures in the design of new drugs for the treatment of infectious diseases.Funding Agency Portuguese Foundation for Science and Technology UID/QUI/00100/2019 UID/MULTI/04326/2019 -CCMAR Portuguese Foundation for Science and Technology SFRH/BPD/99851/2014 IST-ID/115/2018info:eu-repo/semantics/publishedVersio

Low temperature matrix-isolation and solid state vibrational spectra of 5-chlorotetrazole

The vibrational spectra of 5-chlorotetrazole (CN4HCl) isolated in an argon matrix (T ¼ 8.5 K) and in the solid state (at room temperature) were studied. The infrared spectrum of monomers of 5-chlorotetrazole isolated in an argon matrix agrees well with the spectrum predicted theoretically (DFT(B3LYP)/6-31G*) for the 2Htautomer of the compound. The bands assigned to the 1H-tautomer appear in the experimental spectrum as very low intensity features. Based on the relative intensities of the bands in the spectra of the 1H- and 2Htautomers, the relative amount of the first tautomer in this matrix can be estimated as 1%. Three matrixes were deposited with different nozzle temperatures and the enthalpy difference between the tautomers DH ¼ 8.0 kJ mol 1 was estimated using the Van’t Hoff relation. The internal energy difference between the two tautomers was predicted theoretically (DFT B3LYP/6-31G*) as 12.6 kJ mol 1. This is in reasonable agreement with experimental observations. In the crystalline phase, this compound exists in its 1H-tautomeric form. Accordingly, the IR spectrum of polycrystalline 5-chlorotetrazole is well reproduced by the spectrum predicted theoretically for the 1H- tautomer

Toxin profile of two Gymnodinium catenatum strains from Iberian Coastal Waters

Gymnodinium catenatum has been the main species responsible for paralytic shellfish poisoning events along the Portuguese coast (Iberian Peninsula), causing bans on bivalve harvesting that result in huge economic losses. This work presents the characterization of two novel isolates of G. catenatum regarding their growth and toxin profiles. Laboratory growth experiments revealed that, although low growth rates were obtained during cultivation, the cell yields were high compared to those reported in the literature. Evaluation of the toxin profiles, by HPLC-FLD, essentially confirmed the typical composition of toxins of this regional population (Iberian Peninsula), namely, the absence or low representation of the toxins dcNEO, GTX1,4 and NEO and a higher ratio of the toxins C1,2, GTX6 and GTX5. However, the percentage of the identified toxins varied among the strains of this study (under the same isolation, growth, and analysis conditions), and also differed from that of other strains described in the literature. Interestingly, we found a comparatively high abundance of dcSTX in both strains, relative to the other toxins, and an unquantifiable amount of C3,4 toxins. In addition to the geographic relationship between toxin profiles, chemical conversions among toxins may explain some differences encountered in the toxin profiles of G. catenatum strains.info:eu-repo/semantics/publishedVersio

Polyphosphates and poly-β-hydroxybutyrate granules identification through quantitative image analysis in enhanced biological phosphorus removal systems

Enhanced biological phosphorus removal (EBPR) is a widely implemented technique for having the potential to cheaply and reliably remove phosphate from wastewater treatment processes, than traditional chemical methods. EBPR is performed by operating the system sequentially with anaerobic and aerobic conditions. Several studies were already performed ranging from different strategies for the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) to modeling both types of bacterial activities. Until now, slight attention has been given to the development of newer, faster, simpler, and better suited monitoring techniques for this type of system. This work is focused on the development of image analysis techniques for polyphosphates and poly-β-hydroxybutyrate granules in EBPR systems since off-line analyses are labor intensive and not able to be performed in full-scale plants. A lab-scale sequencing batch reactor fed with synthetic wastewater containing volatile fatty acids (VFAs) and orthophosphate was used. The reactor had a working volume of 4 L and was operated with a cycle time of 6 h consisting of 2 h anaerobic, 3 h aerobic, 50 min settling and decanting, and 5 min anaerobic idle periods. In each cycle, 2 L of synthetic wastewater was fed to the reactor in the first 5 min of the anaerobic period, resulting in a hydraulic retention time (HRT) of 12 h. The pH was controlled during both the anaerobic and aerobic periods around 7, and the temperature was controlled at 30 ºC in order to provide selective advantages to GAOs over PAOs. The ratio between chemical oxygen demand (COD) and P in the feed was kept at 10 (gCOD/g P). Biomass samples were collected at the end of the anaerobic and aerobic phases and fixed with phosphate buffer saline solution (PBS) and ethanol. Two fluorescence staining methods were used: (1) DAPI for poly-P identification; and (2) nile blue for poly-β-hydroxybutyrate granules. So far, promising results were achieved regarding the type of images achieved by these fluorescence staining methods and the image analysis procedures still under development

Synthesis, structure and antileishmanial evaluation of endoperoxide–pyrazole hybrids

Leishmaniases are among the most impacting neglected tropical diseases. In attempts to repurpose antimalarial drugs or candidates, it was found that selected 1,2,4-trioxanes, 1,2,4,5-tetraoxanes, and pyrazole-containing chemotypes demonstrated activity against Leishmania parasites. This study reports the synthesis and structure of trioxolane–pyrazole (OZ1, OZ2) and tetraoxane–pyrazole (T1, T2) hybrids obtained from the reaction of 3(5)-aminopyrazole with endoperoxide-containing building blocks. Interestingly, only the endocyclic amine of 3(5)-aminopyrazole was found to act as nucleophile for amide coupling. However, the fate of the reaction was influenced by prototropic tautomerism of the pyrazole heterocycle, yielding 3- and 5-aminopyrazole containing hybrids which were characterized by different techniques, including X-ray crystallography. The compounds were evaluated for in vitro antileishmanial activity against promastigotes of L. tropica and L. infantum, and for cytotoxicity against THP-1 cells. Selected compounds were also evaluated against intramacrophage amastigote forms of L. infantum. Trioxolane–pyrazole hybrids OZ1 and OZ2 exhibited some activity against Leishmania promastigotes, while tetraoxane–pyrazole hybrids proved inactive, most likely due to solubility issues. Eight salt forms, specifically tosylate, mesylate, and hydrochloride salts, were then prepared to improve the solubility of the corresponding peroxide hybrids and were uniformly tested. Biological evaluations in promastigotes showed that the compound OZ1•HCl was the most active against both strains of Leishmania. Such finding was corroborated by the results obtained in assessments of the L. infantum amastigote susceptibility. It is noteworthy that the salt forms of the endoperoxide–pyrazole hybrids displayed a broader spectrum of action, showing activity in both strains of Leishmania. Our preliminary biological findings encourage further optimization of peroxide–pyrazole hybrids to identify a promising antileishmanial lead.info:eu-repo/semantics/publishedVersio

Desenvolvimento de metodologias de análise de imagem para quantificar PHA, polifosfatos e glicogénio intracelular em estações de tratamento de águas residuais

O processo de remoção biológica de fósforo, em estações de tratamento de águas residuais, é um processo efetuado por culturas mistas contendo organismos acumuladores de polifosfatos (PAO) e de glicogénio (GAO). No decurso deste processo os microrganismos podem formar inclusões de glicogénio, polihidroxialcanoatos (PHA) e polifosfatos (poli-P). Neste processo, é fulcral monitorizar o metabolismo intracelular para determinar a sua eficiência. Contudo, a sua monitorização, realizada através de análise químicas em diferido, é laboriosa e morosa. Deste modo, existe uma clara necessidade do desenvolvimento de métodos mais expeditos, como metodologias de análise de imagens, para a monitorização destes polímeros intracelulares. Estas técnicas foram implementadas neste estudo, encontrando-se, no caso da determinação da concentração intracelular de poli-P, em fase de desenvolvimento dos protocolos de coloração e aquisição de imagens. Para a determinação da concentração intracelular de glicogénio, foi obtida uma boa correlação inicial. Na determinação da concentração intracelular de PHA, este estudo foca-se na otimização dos protocolos de coloração e no desenvolvimento do programa de análise de imagem

Floral features, pollination biology and breeding system of Chloraea membranacea Lindl. (Orchidaceae: Chloraeinae)

Background and Aims: The pollination biology of very few Chloraeinae orchids has been studied to date, and most of these studies have focused on breeding systems and fruiting success. Chloraea membranacea Lindl. is one of the few non-Andean species in this group, and the aim of the present contribution is to elucidate the pollination biology, functional floral morphology and breeding system in native populations of this species from Argentina (Buenos Aires) and Brazil (Rio Grande do Sul State). Methods:Floral features were examined using light microscopy, and scanning and transmission electron microscopy. The breeding system was studied by means of controlled pollinations applied to plants, either bagged in the field or cultivated in a glasshouse. Pollination observations were made on natural populations, and pollinator behaviour was recorded by means of photography and video.Key ResultsBoth Argentinean and Brazilian plants were very consistent regarding all studied features. Flowers are nectarless but scented and anatomical analysis indicates that the dark, clavate projections on the adaxial labellar surface are osmophores (scent-producing glands). The plants are self-compatible but pollinator-dependent. The fruit-set obtained through cross-pollination and manual self-pollination was almost identical. The main pollinators are male and female Halictidae bees that withdraw the pollinarium when leaving the flower. Remarkably, the bees tend to visit more than one flower per inflorescence, thus promoting self-pollination (geitonogamy). Fruiting success in Brazilian plants reached 60·78 in 2010 and 46 in 2011. Some pollinarium-laden female bees were observed transferring pollen from the carried pollinarium to their hind legs. The use of pollen by pollinators is a rare record for Orchidaceae in general.ConclusionsChloraea membrancea is pollinated by deceit. Together, self-compatibility, pollinarium texture, pollinator abundance and behaviour may account for the observed high fruiting success. It is suggested that a reappraisal and re-analysis of important flower features in Chloraeinae orchids is necessary.Fil: Sanguinetti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Buzatto, Cristiano Roberto. Universidade Federal do Rio Grande do Sul; BrasilFil: Pedron, Marcelo. Universidade Federal do Rio Grande do Sul; BrasilFil: Davies, Kevin L.. Cardiff University; Reino UnidoFil: Ferreira, Pedro Maria De Abreu. Universidade Federal do Rio Grande do Sul; BrasilFil: Maldonado, Sara Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; ArgentinaFil: Singer, Rodrigo Bustos. Universidade Federal do Rio Grande do Sul; Brasi