Rural communities in developing countries lack access to affordable, reliable, and sustainable forms of energy, which are essential factors for improving living conditions. These communities rely on diesel and kerosene, which are highly polluting compared to renewable energy technologies, to satisfy their energy needs. In this study, hybrid renewable energy systems (HRESs) have been analyzed, which are designed to overcome the fluctuating nature of renewables, for off-grid electrification. The results of this study—which covers many countries and examples—show that the successful integration of HRES is influenced by factors such as government support—and community organization — which is essential to keep these systems operating over the project lifetime. The levelized cost of energy (LCOE) of different mini-grids was compared and analyzed. The results reveal that by comparing the LCOE range of diesel (between USD 0.92/kWh and USD 1.30/kWh), solar photovoltaic (USD 0.40/kWh and USD 0.61/kWh), and hybrid solar photovoltaic/diesel (USD 0.54/kWh to USD 0.77/kWh), diesel is the most expensive technology. Additionally, the study addressed barriers that can hinder the implementation of mini-grids, such as lack of supportive policies and high capital cost. However, governments’ incentives are instrumental in lowering capital costs. These results are of particular importance for developing countries, where electricity supply via HRES is often quicker and cheaper than grid extension. The insights from this paper are a good starting point for in-depth research on optimal local design and ownership models, which can help accelerate the implementation, and lower the costs of sustainable electricity supply in remote areas.

A review of hybrid renewable energy systems in mini-grids for off-grid electrification in developing countries

This work was supported in part by the Spanish Ministry of Science and
Innovation, Grants SAF2009-12606-C02-01 (M.P.), BFU2008-04637 (J.L.V.-I.),
and BFU2009-09268 (I.F., X.C.), by the European Commission Frame Program
7 Grant 201924 (EDICT; M.P. and L.K.), by Consolider E-Science Project and
Fundacion Marcelino Botin (M.O.), and by the computer resources provided
by the Red Espanola de Supercomputacion (M.P.). Additional support from
Generalitat de Catalunya SGR2009-1355 (M.P.) and BP-B2008-00239 (X.C.)
is also acknowledged.

https://digital.csic.es/bitstream/10261/153550/1/Crystal_structure_substrate-bound_amino_acid-Kowalcyk.pdf

Crystal structure of a substrate-bound amino acid antiporter in the outward open conformation: mechanism of substrate recognintion and transport.

All affected patients in four families with autosomal dominant familial renal tubular acidosis (dRTA) were heterozygous for mutations in their red cell HCO3-/Cl- exchanger, band 3 (AE1, SLC4A1) genes, and these mutations were not found in any of the nine normal family members studied. The mutation Arg589--> His was present in two families, while Arg589--> Cys and Ser613--> Phe changes were found in the other families. Linkage studies confirmed the co-segregation of the disease with a genetic marker close to AE1. The affected individuals with the Arg589 mutations had reduced red cell sulfate transport and altered glycosylation of the red cell band 3 N-glycan chain. The red cells of individuals with the Ser613--> Phe mutation had markedly increased red cell sulfate transport but almost normal red cell iodide transport. The erythroid and kidney isoforms of the mutant band 3 proteins were expressed in Xenopus oocytes and all showed significant chloride transport activity. We conclude that dominantly inherited dRTA is associated with mutations in band 3; but both the disease and its autosomal dominant inheritance are not related simply to the anion transport activity of the mutant proteins.

Familial distal renal tubular acidosis is associated with mutations in the red cell anion exchange

Abstract The CAZy database is a web-server for sequence-based classification of carbohydrate-active enzymes that has become the worldwide and indispensable tool for scientists engaged in this research field. It was originally created in 1991 as a classification of glycoside hydrolases (GH) and currently, this section of CAZy represents its largest part counting 172 GH families. The present Opinion paper is devoted to the specificity of α-amylase (EC 3.2.1.1) and its occurrence in the CAZy database. Among the 172 defined GH families, four, i.e. GH13, GH57, GH119 and GH126, may be considered as the α-amylase GH families. This view reflects a historical background and traditions widely accepted during the previous decades with respect to the chronology of creating the individual GH families. It obeys the phenomenon that some amylolytic enzymes, which were used to create the individual GH families and were originally known as α-amylases, according to current knowledge from later, more detailed characterization, need not necessarily represent genuine α-amylases. Our Opinion paper was therefore written in an effort to invite the scientific community to think about that with a mind open to changes and to consider the seemingly unambiguous question in the title as one that may not have a simple answer.

/pdf/how-many-a-amylase-gh-families-are-there-in-the-cazy-1yvljysx.pdf

How many α-amylase GH families are there in the CAZy database?

Amino acid transporters play a vital role in metabolism and nutrient signaling pathways. Typically, transport activity is investigated using single substrates and competing amounts of other amino acids. We used GC-MS and LC-MS for metabolic screening of Xenopus laevis oocytes expressing various human amino acid transporters incubated in complex media to establish their comprehensive substrate profiles. For most transporters, amino acid selectivity matched reported substrate profiles. However, we could not detect substantial accumulation of cationic amino acids by SNAT4 and ATB0,+ in contrast to previous reports. In addition, comparative substrate profiles of two related sodium neutral amino acid transporters known as SNAT1 and SNAT2, revealed the latter as a significant leucine accumulator. As a consequence, SNAT2, but not SNAT1, was shown to be an effective activator of the eukaryotic cellular growth regulator mTORC1. We propose, that metabolomic profiling of membrane transporters in Xe nopus laevis oocytes can be used to test their substrate specificity and role in intracellular signaling pathways.

/pdf/a-gc-ms-single-cell-method-to-evaluate-membrane-transporter-119t1xjrdg.pdf

A GC-MS/Single-Cell Method to Evaluate Membrane Transporter Substrate Specificity and Signaling.

Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.

Stefan Brӧer

Papers

Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology.