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Background Vibrio species display variable and plastic fitness strategies to survive and interact with multiple hosts, including marine aquaculture species that are severely affected by pathogenic Vibrios. The culturable Vibrio sp. strain ArtGut-C1, the focus of this study, provides new evidence of such phenotypic plasticity as it accumulates polyhydroxybutyrate (PHB), a biodegradable polymer with anti-pathogen activity, particularly in the marine larviculture phase. The strain was isolated from the gut of laboratory-reared Artemia individuals, the live diet and PHB carrier used in larviculture. Its main phenotypic properties, taxonomic status and genomic properties are reported based on the whole-genome sequencing. Results Vibrio sp. ArtGut-C1 yielded 72.6% PHB of cells’ dry weight at 25°C. The genomic average nucleotide identity (ANI) shows it is closely related to V. diabolicus (ANI: 88.6%). Its genome contains 5,236,997-bp with 44.8% GC content, 3,710 protein-coding sequences, 96 RNA, 9 PHB genes functionally related to PHB metabolic pathways, and several genes linked to competing and colonizing abilities. Conclusions This culturable PHB-accumulating Vibrio strain shows high genomic and phenotypic variability. It may be used as a natural pathogen biocontrol in the marine hatchery and as a potential cell factory for PHB production. How to cite: Yevenes M, Quiroz M, Maruyama F, et al. Vibrio sp. ArtGut-C1, a polyhydroxybutyrate producer isolated from the gut of the aquaculture live diet Artemia (Crustacea). Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.10.003

The Pampean Plain in Argentina is one of the most extended plain regions of the world with numerous wetland systems and very shallow lakes. Certain anomalies related to geomorphology and shallow lakes’ hydrology are particularly present in a sector of the southern Pampean Plain, specifically, in the southwestern limit of the Quequen Grande River Basin. Here, shallow lakes can be defined as upland-embedded wetlands, characterized by the lack of observable hydrological connectivity due to the absence of surface water flows. The aim of this study was to identify groundwater connectivity of Pampean shallow lakes considered as upland-embedded wetlands and classify them according to their water presence frequency over time and their water source origin based on natural tracers (18O–H2O, 2H–H2O, electrical conductivity and Cl− content). In this work, a methodological framework involving a multitemporal analysis of the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) derived from Landsat data, in addition to field data is proposed. According to water presence frequency, shallow lakes were classified in four categories: occasionally (89.0 %), regularly (6.7 %), usually (1.9 %) and permanently (2.3 %) with water. Obtained results allowed identifying shallow lakes having low, moderate or high mineralized water due to both different evaporation degree and water sources.

This paper gives an account of the design a logic-based approach for identifying potential infiltration areas in low-gradient watersheds based on remote sensing data. This methodological framework is applied in a sector of the Pampa Plain, Argentina, which has high level of agricultural activities and large demands for groundwater supplies. Potential infiltration sites are assessed as a function of two primary topics: hydrologic and soil conditions. This model shows the state of each evaluated subwatershed respecting to its potential contribution to infiltration mainly based on easily measurable and commonly used parameters: drainage density, geomorphologic units, soil media, land-cover, slope and aspect (slope orientation). Mapped outputs from the logic model displayed 42% very low-low, 16% moderate, 41% high-very high contribution to potential infiltration in the whole watershed. Subwatersheds in the upper and lower section were identified as areas with high to very high potential infiltration according to the following media features: low drainage density (

Fresh water is of vital importance and therefore, the availability of water in urban areas has been a priority objective in the world for many years. One of the greatest challenges related to any natural resource management process is to achieve the best possible compatibility between the “ideal” and the “possible” situations. Nowadays, urban water management is a key objective particularly in intermediate cities of developing countries where human and economic resources in governmental agencies are limited. So, it is necessary to count with a tool as simple as possible, in order to allow control efforts to be prioritised. The aim of this paper is to develop a hazard index (HI), in order to identify which point sources of groundwater contamination need to be more frequently controlled and to recognise public supply wells that may be threatened. This index was applied in Mar del Plata city, located in the south-east of the Buenos Aires province, Argentina. The HI was defined as a weighted sum of three variables: Potential Contamination Load (PCL), Effluent Disposal mode (ED) and the distance from the point source to groundwater supply wells or Well Protection Areas (WP). HI results for each point source showed that all buried fuel tanks, soil and stone quarries present high HI as well as 2% of the industries. On the other hand, 90% of the inventoried industries and a landfill present the lowest HI values. Some recommendations based on two strategies (mitigation or prevention) are proposed.

The synthesis, complete characterization, and solid state conformation of a new series of p-tert-butylcalix[5]arene (ButC5) mono-, di-, tri- and pentaanions are reported. X-ray structures of the alkali metal salts illustrate the strong influence of the alkali metal ion on the structure of the calixanion. The strength of the alkali metal base and its reaction stoichiometry play an important role in the conformation and level of deprotonation of the resulting anion. Reaction of ButC5 in a 2:1 molar ratio with alkali metal bases M2CO3 (M = Rb, Cs), or in a 1:1 ratio with M2CO3 (M = Na, K), MOH (M = Na, K, Rb, Cs) or MH (M = Li, Na) produces ButC5 monoanions, but ButC5 reacts in a 1:1 molar ratio with M2CO3 (M = Rb, Cs) or a 1:2 molar ratio with MOC(CH3)3 (M = Na, K) to afford ButC5 dianions. Due to the steric bulkiness of the But group no polymeric structures are observed. Alkali metal salts of trianionic ButC5 were obtained in high yields from reactions of ButC5 with MOC(CH3)3 (M = Li, Na, K), BunLi, LiH and LiOH in a 1:3 molar ratio. Pentaanionic ButC5 salts were obtained by the reaction with MOC(CH3)3 (M = Li, Na, K) or BunLi in a 5:1 ratio. X-ray crystal structures of ButC5 · Na and ButC5 · Cs indicate that the size of the alkali metal influences the level of cation-π arene interactions and therefore the conformation of the ButC5 unit; for example, ButC5 · Na has a cone conformation while ButC5 · Cs shows a flattened cone conformation. Cation-π arene interactions are observed in most of the calixarene salts.