Disinfection guidelines exist for pathogen inactivation in potable water and recycled water, but wastewater with high numbers of particles can be more difficult to disinfect, making compliance with ...the guidelines problematic. Disinfection guidelines specify that drinking water with turbidity ≥1 Nephelometric Turbidity Units (NTU) is not suitable for disinfection and therefore not fit for purpose. Treated wastewater typically has higher concentrations of particles (1-10NTU for secondary treated effluent). Two processes widely used for disinfecting wastewater are chlorination and ultraviolet radiation. In both cases, particles in wastewater can interfere with disinfection and can significantly increase treatment costs by increasing operational expenditure (chemical demand, power consumption) or infrastructure costs by requiring additional treatment processes to achieve the required levels of pathogen inactivation. Many microorganisms (viruses, bacteria, protozoans) associate with particles, which can allow them to survive disinfection processes and cause a health hazard. Improved understanding of this association will enable development of cost-effective treatment, which will become increasingly important as indirect and direct potable reuse of wastewater becomes more widespread in both developed and developing countries. This review provides an overview of wastewater and associated treatment processes, the pathogens in wastewater, the nature of particles in wastewater and how they interact with pathogens, and how particles can impact disinfection processes.
•A 1D finite element formulation for a homogenized beam model for lattice systems.•Elastostatic cell properties are enough to estimate the entire structural response.•Novel stiffness and mass ...matrices for 1D modeling of reticulated structures.•Validation through parametric studies and the analysis of a realistic building.•Numerical results show that the proposed formulation is accurate and efficient.
This paper presents a finite element formulation of an existing homogenized beam-like model for the description of reticulated structures transverse dynamics. This work deals with elastic periodic lattice structures such as foams, crystals, honeycombs, or multi-story buildings, whose unit cell is made of interconnected beams or plates and repeats itself in one direction. The studied model is a one-dimensional enriched form of the fourth-order Timoshenko beam equation, and the motion is described by a sixth-order differential equation. The higher differential equation order is attributed to an additional kinematic mechanism that may appear under large stiffness contrasts between the cell elements. In this context, the construction of an original finite element approximate solution is proposed. Weak formulations lead to generalized elementary stiffness and mass matrices. Through the analysis of a realistic building in the linear elasticity framework, it is shown that this homogenized beam finite element solution recovers the analytical results and is close to the full detailed finite element structural model. This new formulation simplifies the implementation of the beam-like model in complex configurations, enables parametric studies, and could be easily used for a wide range of applications in structural dynamics, other than free vibration analysis, at reduced computational costs.
Isoniazid (INH) is converted into isonicotinyl radical through its interaction with the catalase-peroxidase (katG) enzyme present in the cells of Mycobacterium tuberculosis (M. tb.), the bacteria ...that causes the tuberculosis disease. This process is important because resistance of M. tb. cells to INH treatment has been associated with the failure of completion of this process. However, this process is poorly understood and there are a variety of conflicting theories about the details of the mechanism of this process. One theory suggests that INH binds to katG and transfers a single electron to the heme while the heme is in its two electron oxidized state, compound I Fe(iv)Por˙+ (CpdI). In this study, DFT calculations at the UB3LYP/6-31g(d)-LANL2DZ level of theory are used to study the M. tb. katG CpdI molecule. Different models of the M. tb. CpdI molecule were prepared and the calculations revealed the impact of Trp321 on the electronic properties of the heme. Without Trp321 the heme assumed a triradical state with single electrons on the πxy and πyz orbitals of Fe and another on the a2u orbital of the porphyrin ring that can either be coupled with the first two, to assume a quartet state, or decoupled to form a doublet state. With Trp321, however, a transfer of an electron from the πTrp orbital to a2u porphyrin orbital leads to loss of radical character of the porphyrin and leaves the Trp321 group with a radical character. INH was observed to have strong interaction with CpdI and the absence of Trp321 significantly decreased the binding energy by 2 kcal mol-1 explaining the importance of Trp321 in the binding of INH. The results in this study show the importance of Trp321 in the binding of INH and its effect on its electronic properties, which is consistent with previous experimental findings that mutation of Trp321 results in an increase in drug resistance.
•A novel polysaccharide from Pleurotus eryngii was extracted and characterized.•A partially methylated mannogalactan (MG-Pe) was described.•MG-Pe was non-cytotoxic to murine melanoma cells but ...reduced in vitro invasion.•Growth of induced solid tumor (melanoma) in mice was reduced 60% by MG-Pe.•MG-Pe treatment does not alter physiological parameters of C57BL/6 mice.
A heteropolysaccharide was isolated by cold aqueous extraction from edible mushroom Pleurotus eryngii (“King Oyster”) basidiocarps and its biological properties were evaluated. Structural assignments were carried out using mono- and bidimensional NMR spectroscopy, monosaccharide composition, and methylation analyses. A mannogalactan having a main chain of (1→6)-linked α-d-galactopyranosyl and 3-O-methyl-α-d-galactopyranosyl residues, both partially substituted at OH-2 by β-d-Manp (MG-Pe) single-unit was found. Biological effects of mannogalactan from P. eryngii (MG-Pe) were tested against murine melanoma cells. MG-Pe was non-cytotoxic, but reduced in vitro melanoma cells invasion. Also, 50mg/kg MG-Pe administration to melanoma-bearing C57BL/6 mice up to 10days decreased in 60% the tumor volume compared to control. Additionally, no changes were observed when biochemical profile, complete blood cells count (CBC), organs, and body weight were analyzed. Mg-Pe was shown to be a promising anti-melanoma molecule capable of switching melanoma cells to a non-invasive phenotype with no toxicity to melanoma-bearing mice.
Plant parasitic nematodes are among the greatest consumers of primary production in terrestrial ecosystems. Their feeding strategies can be divided into endoparasites and ectoparasites that differ ...substantially, not only in their damage potential to host tissue and primary production, but also in their susceptibility to environmental changes. Climate change is predicted to increase variability of precipitation in many systems, yet the effects on belowground biodiversity and associated impacts on primary productivity remain poorly understood. To examine the impact of altered precipitation on endo- and ectoparasitic soil nematodes, we conducted a 2-year precipitation manipulation study across an arid, a semiarid, and a mesic grassland. Plant parasite feeding type abundance, functional guilds, and herbivory index in response to precipitation were evaluated. Responses of endo- and ectoparasites to increased precipitation varied by grassland type. There was little response of ectoparasites to increased precipitation although their population declined at the mesic site with increased precipitation. The abundance of endoparasites remained unchanged with increasing precipitation at the arid site, increased at the semiarid, and decreased at the mesic site. The herbivory index followed closely the trends seen in the endoparasites response by stagnating at the arid site, increasing at the semiarid, and decreasing at the mesic site. Our findings suggest that altered precipitation has differing effects on plant parasite feeding strategies as well as functional guilds. This may have important implications for grassland productivity, as plant parasite pressure may exacerbate the effects of climate change on host plants.
In the southwest South Atlantic Ocean (SWAO) strong ocean surface warming hotspots have been observed mainly along the path of the Brazil Current (BC), Brazil-Malvinas Confluence (BMC), and in the ...Río de la Plata (RdlP). However, there is no knowledge about the signature of ocean hotspots below the surface and the potential effects of ocean warming on marine biota. In this work, we provide initial evidence of how deep the hotspots of the SWAO extend in the water column, in particular at mid-water and bottom layers where two marine species ‒the green turtle (Chelonia mydas) and the Patagonian scallop (Zygochlamys patagonica)‒ inhabit. We compare 15 years (2003–2017) of Copernicus Marine Environment Monitoring Service (CMEMS) ARMOR3D high‐resolution (1/4°) 3-D temperatures reprocessed from combined satellite and in-situ observations with high‐resolution (1/12°) Mercator ocean reanalysis. We also use location data of C. mydas and Z. patagonica to discuss the potential impacts of warming on these species in terms of geographic distribution, phenological shifts and thermal tolerance. The potential distribution of C. mydas changes in relation to the sea surface temperature (SST) and the bathymetry. The warming of the whole water column in the RdlP (> 0.4°C/decade) and the southward movement of the mean surface isotherms, which likely drove turtle displacements, could enable the opening up of novel optimal thermal habitats and/or a longer seasonal residency for the species. At the BMC, warming is driven by the southward displacement of the BC during the past decades. Ocean model temperature indicates cooling/warming in deep waters along the outer shelf and shelf break regions, which vary according the displacements of the BMC. The expected warming of the waters over the Patagonian scallop largest bed could exceed the thermal tolerance of this species and its survival. Given the lack of long-term monitoring programs to address the impacts of climate change on marine biota in the SWAO, our results provide the first effort to call the attention of stakeholders and decision makers on marine conservation and fishery management to work towards better management strategies in the context of climate change.
There are very few taxonomic studies of Brazilian sipunculan worms, and the species occurring along the northern coasts are largely understudied. We report herein the occurrence of four shallow water ...species along the intertidal zones of Bahia and Pernambuco states. Antillesoma antillarum (Grbe & Oersted, 1858) occurs from underneath beach rocks or within sandstone reefs and may reach high densities. The large species Sipunculus (Sipunculus) nudus Linnaeus, 1766, Sipunculus polymyotus Fisher, 1947, and Xenosiphon branchiatus (Fischer, 1895) were collected in sandy-mud, low-energy intertidal environments. For the first time, we report that sipunculans are collected and used as fishing bait by local fishermen in the Western Atlantic. All species are fully described, including notes on their external and internal anatomy.
Transovarial transmission is the most reliable way of passing on essential nutrient-providing endosymbionts from mothers to offspring. However, not all endosymbiotic microbes follow the complex path ...through the female host tissues to oocytes on their own. Here, we demonstrate an unusual transmission strategy adopted by one of the endosymbionts of the planthopper Trypetimorpha occidentalis (Hemiptera: Tropiduchidae) from Bulgaria. In this species, an Acetobacteraceae endosymbiont is transmitted transovarially within deep invaginations of cellular membranes of an ancient endosymbiont Sulcia—strikingly resembling recently described plant virus transmission. However, in males, Acetobacteraceae colonizes the same bacteriocytes as Sulcia but remains unenveloped. Then, the unusual endobacterial localization of Acetobacteraceae observed in females appears to be a unique adaptation to maternal transmission. Further, the symbiont’s genomic features, including encoding essential amino acid biosynthetic pathways and its similarity to a recently described psyllid symbiont, suggest a unique combination of the ability to horizontally transmit among species and confer nutritional benefits. The close association with Acetobacteraceae symbiont correlates with the so-far-unreported level of genomic erosion of ancient nutritional symbionts of this planthopper. In Sulcia, this is reflected in substantial changes in genomic organization, reported for the first time in the symbiont renowned for its genomic stability. In Vidania, substantial gene loss resulted in one of the smallest genomes known, at 108.6 kb. Thus, the symbionts of T. occidentalis display a combination of unusual adaptations and genomic features that expand our understanding of how insect–microbe symbioses may transmit and evolve.IMPORTANCEReliable transmission across host generations is a major challenge for bacteria that associate with insects, and independently established symbionts have addressed this challenge in different ways. The facultatively endobacterial localization of Acetobacteraceae symbiont, enveloped by cells of ancient nutritional endosymbiont Sulcia in females but not males of the planthopper Trypetimorpha occidentalis, appears to be a unique adaptation to maternal transmission. Acetobacteraceae’s genomic features indicate its unusual evolutionary history, and the genomic erosion experienced by ancient nutritional symbionts demonstrates the apparent consequences of such close association. Combined, this multi-partite symbiosis expands our understanding of the diversity of strategies that insect symbioses form and some of their evolutionary consequences.
Mechanochemistry is considered an alternative attractive greener approach to prepare diverse molecular compounds and has become an important synthetic tool in different fields (e.g., physics, ...chemistry, and material science) since is considered an ecofriendly procedure that can be carried out under solvent free conditions or in the presence of minimal quantities of solvent (catalytic amounts). Being able to substitute, in many cases, classical solution reactions often requiring significant amounts of solvents. These sustainable methods have had an enormous impact on a great variety of chemistry fields, including catalysis, organic synthesis, metal complexes formation, preparation of multicomponent pharmaceutical solid forms, etc. In this sense, we are interested in highlighting the advantages of mechanochemical methods on the obtaining of pharmaceutical cocrystals. Hence, in this review, we describe and discuss the relevance of mechanochemical procedures in the formation of multicomponent solid forms focusing on pharmaceutical cocrystals. Additionally, at the end of this paper, we collect a chronological survey of the most representative scientific papers reporting the mechanochemical synthesis of cocrystals.
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