Broadening The Substrate Scope of Aldolases Through Metagenomic Enzyme Discovery.

Bio-processes based on enzymatic catalysis play a major role in the development of green, sustainable processes, and the discovery of new enzymes is key to this approach. In this work, we analysed ten metagenomes and retrieved 48 genes coding for deoxyribose-5-phosphate aldolases (DERAs, EC 4.1.2.4) using a sequence-based approach. These sequences were recombinantly expressed in Escherichia coli and screened for activity towards a range of aldol additions. Among these, one enzyme, DERA-61, proved to be particularly interesting and catalysed the aldol addition of furfural or benzaldehyde with acetone, butanone and cyclobutanone with unprecedented activity. The product of these reactions, aldols, can find applications as building blocks in the synthesis of biologically active compounds. Screening was carried out to identify optimized reaction conditions targeting temperature, pH, and salt concentrations. Lastly, the kinetics and the stereochemistry of the products were investigated, revealing that DERA-61 and other metagenomic DERAs have superior activity and stereoselectivity when they are provided with non-natural substrates, compared to well-known DERAs.

Transposable element landscapes illuminate past evolutionary events in the endangered fern Vandenboschia speciosa.

Vandenboschia speciosa is an endangered tetraploid fern species with a large genome (10.5 Gb). Its geographical distribution is characterized by disjoined tertiary flora refuges, with relict populations that survived past climate crises. Here, we analyzed the transposable elements (TEs) and found that they comprise approximately 76% of the V. speciosa genome, thus being the most abundant type of DNA sequence in this gigantic genome. The V. speciosa genome is composed of 51% and 5.6% of Class I and Class II elements, respectively. LTR retrotransposons were the most abundant TEs in this species (at least 42% of the genome), followed by non-LTR retrotransposons, which constituted at least 8.7% of the genome of this species. We introduce an additional analysis to identify the nature of non-annotated elements (19% of the genome). A BLAST search of the non-annotated contigs against the V. speciosa TE database allowed for the identification of almost half of them, which were most likely diverged sequence variants of the annotated TEs. In general, the TE composition in V. speciosa resembles the TE composition in seed plants. In addition, repeat landscapes revealed three episodes of amplification for all TEs, most likely due to demographic changes associated with past climate crises.

Molecular Simulations of Surfactant Adsorption on Iron Oxide from Hydrocarbon Solvents.

The performance of organic friction modifiers (OFMs) depends on their ability to adsorb onto surfaces and form protective monolayers. Understanding the relationship between OFM concentration in the base oil and the resulting surface coverage is important for improving lubricant formulations. Here, we use molecular dynamics (MD) simulations to study the adsorption of three OFMs─stearic acid (SA), glycerol monoostearate (GMS), and glycerol monooleate (GMO)─onto a hematite surface from two hydrocarbon solvents─n-hexadecane and poly(α-olefin) (PAO). We calculate the potential of mean force of the adsorption process using the adaptive biasing force algorithm, and the adsorption strength increases in the order SA < GMS < GMO. We estimate the minimum area occupied by OFM molecules on the surface using annealing MD simulations and obtained a similar hard-disk area for GMS and GMO but a lower value for SA. Using the MD results, we determine the adsorption isotherms using the molecular thermodynamic theory (MTT), which agree well with one previous experimental data set for SA on hematite. For two other experimental data sets for SA, lateral interactions between surfactant molecules need to be accounted for within the MTT framework. SA forms monolayers with lower surface coverage than GMO and GMS at low concentrations but also has the highest plateau coverage. We validate the adsorption energies from the MD simulations using high-frequency reciprocating rig friction experiments with different concentrations of the OFMs in PAO. For OFMs with saturated tailgroups (SA and GMS), we obtain good agreement between the simulations and the experiments. The results deviate for OFMs containing Z-unsaturated tailgroups (GMO) due to the additional steric hindrance, which is not accounted for in the current simulation framework. This study demonstrates that MD simulations, alongside MTT, are an accurate and efficient tool to predict adsorption isotherms at solid-liquid interfaces.

Gene expression changes elicited by a parasitic B chromosome in the grasshopper Eyprepocnemis plorans are consistent with its phenotypic effects.

Parasitism evokes adaptive physiological changes in the host, many of which take place through gene expression changes. This response can be more or less local, depending on the organ or tissue affected by the parasite, or else systemic when the parasite affects the entire host body. The most extreme of the latter cases is intragenomic parasitism, where the parasite is present in all host nuclei as any other genomic element. Here, we show the molecular crosstalk between a parasitic chromosome (also named B chromosome) and the host genome, manifested through gene expression changes. The transcriptome analysis of 0B and 1B females of the grasshopper Eyprepocnemis plorans, validated by a microarray experiment performed on four B-lacking and five B-carrying females, revealed changes in gene expression for 188 unigenes being consistent in both experiments. Once discarded B-derived transcripts, there were 46 differentially expressed genes (30 up- and 16 downregulated) related with the adaptation of the host genome to the presence of the parasitic chromosome. Interestingly, the functions of these genes could explain some of the most important effects of B chromosomes, such as nucleotypic effects derived from the additional DNA they represent, chemical defense and detoxification, protein modification and response to stress, ovary function, and regulation of gene expression. Collectively, these changes uncover an intimate host-parasite interaction between A and B chromosomes during crucial steps of gene expression and protein function.

Chromosomal Rearrangements during Turtle Evolution Altered the Synteny of Genes Involved in Vertebrate Sex Determination.

Sex-determining mechanisms (SDMs) set an individual's sexual fate by its genotype (genotypic sex determination, GSD) or environmental factors like temperature (temperature- dependent sex determination, TSD), as in turtles where the GSD "trigger" remains unknown. SDMs co-evolve with turtle chromosome number, perhaps because fusions/fissions alter the relative position/regulation of sexual development genes. Here, we map 10 such genes via FISH onto metaphase chromosomes in 6 TSD and 6 GSD turtles for the first time. Results uncovered intrachromosomal rearrangements involving 3 genes across SDMs (Dax1, Fhl2, and Fgf9) and a chromosomal fusion linking 2 genes (Sf1 and Rspo1) in 1 chromosome in a TSD turtle (Pelomedusa subrufa) that locate to 2 chromosomes in all others. Notably, Sf1 and its repressor Foxl2 map to Apalone spinifera's ZW chromosomes but to a macro- (Foxl2) and a microautosome (Sf1) in other turtles potentially inducing SDM evolution. However, our phylogenetically informed analysis refutes Foxl2 (but not Sf1) as Apalone's master sex-determining gene. The absence of common TSD-specific or GSD-specific rearrangements underscores the independent evolutionary trajectories of turtle SDMs. Further comparative analyses using more genes from the sexual development network are warranted to inform genome evolution and its contribution to enigmatic turnovers of vertebrate sex determination.

Direct Alkylation of Amines with Primary and Secondary Alcohols through Biocatalytic Hydrogen Borrowing.

The reductive aminase from Aspergillus oryzae (AspRedAm) was combined with a single alcohol dehydrogenase (either metagenomic ADH-150, an ADH from Sphingobium yanoikuyae (SyADH), or a variant of the ADH from Thermoanaerobacter ethanolicus (TeSADH W110A)) in a redox-neutral cascade for the biocatalytic alkylation of amines using primary and secondary alcohols. Aliphatic and aromatic secondary amines were obtained in up to 99 % conversion, as well as chiral amines directly from the racemic alcohol precursors in up to >97 % ee, releasing water as the only byproduct.

B-chromosome effects on Hsp70 gene expression does not occur at transcriptional level in the grasshopper Eyprepocnemis plorans.

As intragenomic parasites, B chromosomes can elicit stress in the host genome, thus inducing a response for host adaptation to this kind of continuous parasitism. In the grasshopper Eyprepocnemis plorans, B-chromosome presence has been previously associated with a decrease in the amount of the heat-shock protein 70 (HSP70). To investigate whether this effect is already apparent at transcriptional level, we analyze the expression levels of the Hsp70 gene in gonads and somatic tissues of males and females with and without B chromosomes from two populations, where the predominant B chromosome variants (B2 and B24) exhibit different levels of parasitism, by means of quantitative real-time PCR (qPCR) on complementary DNA (cDNA). The results revealed the absence of significant differences for Hsp70 transcripts associated with B-chromosome presence in virtually all samples. This indicates that the decrease in HSP70 protein levels, formerly reported in this species, may not be a consequence of transcriptional down-regulation of Hsp70 genes, but the result of post-transcriptional regulation. These results will help to design future studies oriented to identifying factors modulating Hsp70 expression, and will also contribute to uncover the biological role of B chromosomes in eukaryotic genomes.

The Ku70 DNA-repair protein is involved in centromere function in a grasshopper species.

The Ku70 protein is involved in numerous cell functions, the nonhomologous end joining (NHEJ) DNA repair pathway being the best known. Here, we report a novel function for this protein in the grasshopper Eyprepocnemis plorans. We observed the presence of large Ku70 foci on the centromeres of meiotic and mitotic chromosomes during the cell cycle stages showing the highest centromeric activity (i.e., metaphase and anaphase). The fact that colchicine treatment prevented centromeric location of Ku70, suggests a microtubule-dependent centromeric function for Ku70. Likewise, the absence of Ku70 at metaphase-anaphase centromeres from three males whose Ku70 gene had been knocked down using interference RNA, and the dramatic increase in the frequency of polyploid spermatids observed in these males, suggest that the centromeric presence of Ku70 is required for normal cytokinesis in this species. The centromeric function of Ku70 was not observed in 14 other grasshopper and locust species, or in the mouse, thus suggesting that it is an autapomorphy in E. plorans.

Cooperative chemoenzymatic and biocatalytic cascades to access chiral sulfur compounds bearing C(sp3)-S stereocentres.

Biocatalysis has been widely employed for the generation of carbon-carbon/heteroatom stereocentres, yet its application in chiral C(sp3)-S bond construction is rare and limited to enzymatic kinetic resolutions. Herein, we describe the enantioselective construction of chiral C(sp3)-S bonds through ene-reductase biocatalyzed conjugate reduction of prochiral vinyl sulfides. A series of cooperative sequential/concurrent chemoenzymatic and biocatalytic cascades have been developed to access a broad range of chiral sulfides, including valuable ß-hydroxysulfides bearing two adjacent C(sp3)-S and C(sp3)-O stereocentres, in a stereoconvergent manner with good to excellent yields (up to 96%) and enantioselectivities (up to >99% ee). Notably, this biocatalytic strategy allows to overcome the long-standing shortcomings of catalyst poisoning and C(sp2)/C(sp3)-S bond cleavage faced in transition-metal-catalyzed hydrogenation of vinyl sulfides. Finally, the potential of this methodology is also exemplified by its broader application in the stereoconvergent assembly of chiral C(sp3)-N/O/Se bonds with good to excellent enantioselctivities.

Fournier's Gangrene in an Elderly Male: A Case Report.

Fournier's gangrene (FG) is a rapidly progressing necrotizing soft tissue infection of the perineum with potential multiorgan involvement, posing significant mortality risks. This case report highlights the clinical presentation, potential risk factors, and emphasizes the critical necessity of immediate antibiotic therapy and surgical debridement, regardless of the causative agents involved. We also aim to provide new images to better visualize a diagnosis of Fournier's gangrene. We present the case of a 65-year-old male with a history of self-care neglect, hypertension, and extensive tobacco use. The patient presented to the emergency department exhibiting classical symptoms of systemic illness, necessitating a collaborative diagnostic and therapeutic approach involving various medical specialties including family medicine, urology, general surgery, interventional radiology, infectious disease, pharmacy, intensive care, social service, and palliative care teams. Despite aggressive interventions during his 24-day hospitalization, the patient's clinical condition progressively deteriorated. This case underscores the significance of early detection, timely intervention, and interdisciplinary cooperation in optimizing outcomes for patients with Fournier's gangrene.

Trapeziometacarpal Dislocations in Pediatric Age, Is There a Better Treatment? Series of Cases and a Systematic Review.

(1) Background: Dislocations of the trapeziometacarpal joint (TMC) are uncommon in children and adolescents. Only a few isolated cases are reported in the literature. Therapeutic guidance is minimal and inconclusive. (2) Methods: The authors present four patients treated for this unusual lesion. We evaluated the evolution according to treatment, age, patient activity, and quickDASH. Despite the clear limitation of the small number of patients, it is relevant to try to better understand this lesion and its evolution. A systematic review of the literature was also conducted. (3) Results: This is the largest published series of TMC dislocations in children and adolescents. Patients included a 12-year-old girl treated conservatively with a poor quickDASH; a 9-year-old girl treated surgically with the Eaton-Littler technique for a new dislocation with a partially modified quickDASH; a 13-year-old boy with two necessary closed reductions for a new dislocation and a very good final quickDASH; and a 12-year-old boy treated with closed reduction and percutaneous fixation with excellent final results with quickDASH. (4) Conclusions: In the absence of scientific evidence, conservative treatment and ligament reconstruction did not provide good functionality. In contrast, closed reduction with percutaneous fixation provided excellent results. Therefore, the authors would recommend closed reduction and percutaneous needle fixation as an elective method to treat TMC dislocations in pediatric and adolescent patients.

Realizing the Continuous Chemoenzymatic Synthesis of Anilines Using an Immobilized Nitroreductase.

The use of biocatalysis for classically synthetic transformations has seen an increase in recent years, driven by the sustainability credentials bio-based approaches can offer the chemical industry. Despite this, the biocatalytic reduction of aromatic nitro compounds using nitroreductase biocatalysts has not received significant attention in the context of synthetic chemistry. Herein, a nitroreductase (NR-55) is demonstrated to complete aromatic nitro reduction in a continuous packed-bed reactor for the first time. Immobilization on an amino-functionalized resin with a glucose dehydrogenase (GDH-101) permits extended reuse of the immobilized system, all operating at room temperature and pressure in aqueous buffer. By transferring into flow, a continuous extraction module is incorporated, allowing the reaction and workup to be continuously undertaken in a single operation. This is extended to showcase a closed-loop aqueous phase, permitting reuse of the contained cofactors, with a productivity of >10 gproduct gNR-55-1 and milligram isolated yields >50% for the product anilines. This facile method removes the need for high-pressure hydrogen gas and precious-metal catalysts and proceeds with high chemoselectivity in the presence of hydrogenation-labile halides. Application of this continuous biocatalytic methodology to panels of aryl nitro compounds could offer a sustainable approach to its energy and resource-intensive precious-metal-catalyzed counterpart.

Tandem Repeat DNA Provides Many Cytological Markers for Hybrid Zone Analysis in Two Subspecies of the Grasshopper Chorthippus parallelus.

Recent advances in next generation sequencing (NGS) have greatly increased our understanding of non-coding tandem repeat (TR) DNA. Here we show how TR DNA can be useful for the study of hybrid zones (HZ), as it serves as a marker to identify introgression in areas where two biological entities come in contact. We used Illumina libraries to analyse two subspecies of the grasshopper Chorthippus parallelus, which currently form a HZ in the Pyrenees. We retrieved a total of 152 TR sequences, and used fluorescent in situ hybridization (FISH) to map 77 families in purebred individuals from both subspecies. Our analysis revealed 50 TR families that could serve as markers for analysis of this HZ, using FISH. Differential TR bands were unevenly distributed between chromosomes and subspecies. Some of these TR families yielded FISH bands in only one of the subspecies, suggesting the amplification of these TR families after the geographic separation of the subspecies in the Pleistocene. Our cytological analysis of two TR markers along a transect of the Pyrenean hybrid zone showed asymmetrical introgression of one subspecies into the other, consistent with previous findings using other markers. These results demonstrate the reliability of TR-band markers for hybrid zone studies.

Elucidating the nature of the proton radioactivity and branching ratio on the first proton emitter discovered 53mCo.

The observation of a weak proton-emission branch in the decay of the 3174-keV 53mCo isomeric state marked the discovery of proton radioactivity in atomic nuclei in 1970. Here we show, based on the partial half-lives and the decay energies of the possible proton-emission branches, that the exceptionally high angular momentum barriers, [Formula: see text] and [Formula: see text], play a key role in hindering the proton radioactivity from 53mCo, making them very challenging to observe and calculate. Indeed, experiments had to wait decades for significant advances in accelerator facilities and multi-faceted state-of-the-art decay stations to gain full access to all observables. Combining data taken with the TASISpec decay station at the Accelerator Laboratory of the University of Jyväskylä, Finland, and the ACTAR TPC device on LISE3 at GANIL, France, we measured their branching ratios as bp1 = 1.3(1)% and bp2 = 0.025(4)%. These results were compared to cutting-edge shell-model and barrier penetration calculations. This description reproduces the order of magnitude of the branching ratios and partial half-lives, despite their very small spectroscopic factors.

Epistatic selection on a selfish Segregation Distorter supergene - drive, recombination, and genetic load.

Meiotic drive supergenes are complexes of alleles at linked loci that together subvert Mendelian segregation resulting in preferential transmission. In males, the most common mechanism of drive involves the disruption of sperm bearing one of a pair of alternative alleles. While at least two loci are important for male drive-the driver and the target-linked modifiers can enhance drive, creating selection pressure to suppress recombination. In this work, we investigate the evolution and genomic consequences of an autosomal, multilocus, male meiotic drive system, Segregation Distorter (SD) in the fruit fly, Drosophila melanogaster. In African populations, the predominant SD chromosome variant, SD-Mal, is characterized by two overlapping, paracentric inversions on chromosome arm 2R and nearly perfect (~100%) transmission. We study the SD-Mal system in detail, exploring its components, chromosomal structure, and evolutionary history. Our findings reveal a recent chromosome-scale selective sweep mediated by strong epistatic selection for haplotypes carrying Sd, the main driving allele, and one or more factors within the double inversion. While most SD-Mal chromosomes are homozygous lethal, SD-Mal haplotypes can recombine with other, complementing haplotypes via crossing over, and with wildtype chromosomes via gene conversion. SD-Mal chromosomes have nevertheless accumulated lethal mutations, excess non-synonymous mutations, and excess transposable element insertions. Therefore, SD-Mal haplotypes evolve as a small, semi-isolated subpopulation with a history of strong selection. These results may explain the evolutionary turnover of SD haplotypes in different populations around the world and have implications for supergene evolution broadly.

Chromosome-Scale Genome Assembly of the Hexaploid Taiwanese Goosefoot "Djulis" (Chenopodium formosanum).

Djulis (Chenopodium formosanum Koidz.) is a crop grown since antiquity in Taiwan. It is a BCD-genome hexaploid (2n = 6x = 54) domesticated form of lambsquarters (C. album L.) and a relative of the allotetraploid (AABB) C. quinoa. As with quinoa, djulis seed contains a complete protein profile and many nutritionally important vitamins and minerals. While still sold locally in Taiwanese markets, its traditional culinary uses are being lost as diets of younger generations change. Moreover, indigenous Taiwanese peoples who have long safeguarded djulis are losing their traditional farmlands. We used PacBio sequencing and Hi-C-based scaffolding to produce a chromosome-scale, reference-quality assembly of djulis. The final genome assembly spans 1.63 Gb in 798 scaffolds, with 97.8% of the sequence contained in 27 scaffolds representing the nine haploid chromosomes of each sub-genome of the species. Benchmarking of universal, single-copy orthologs indicated that 98.5% of the conserved orthologous genes for Viridiplantae are complete within the assembled genome, with 92.9% duplicated, as expected for a polyploid. A total of 67.8% of the assembly is repetitive, with the most common repeat being Gypsy long terminal repeat retrotransposons, which had significantly expanded in the B sub-genome. Gene annotation using Iso-Seq data from multiple tissues identified 75,056 putative gene models. Comparisons to quinoa showed strong patterns of synteny which allowed for the identification of homoeologous chromosomes, and sub-genome-specific sequences were used to assign homoeologs to each sub-genome. These results represent the first hexaploid genome assembly and the first assemblies of the C and D genomes of the Chenopodioideae subfamily.

Cardiopulmonary Imaging Utilization and Findings among Hospitalized COVID-19 Patients in Latin America: (From "RIMAC: Registry IMAging Cardiopulmonary among Hospitalized COVID-19 Patients in LATAM").

Objectives: Describe the use and findings of cardiopulmonary imaging-chest X-ray (cX-ray), echocardiography (cEcho), chest CT (cCT), lung ultrasound (LUS), and/or cardiac magnetic resonance imaging (cMRI)-in COVID-19 hospitalizations in Latin America (LATAM). Background: There is a lack of information on the images used and their findings during the SARS-CoV-2 pandemic in LATAM. Methods: Multicenter, prospective, observational study of COVID-19 inpatients, conducted from March to December 2020, from 12 high-complexity centers, in nine LATAM countries. Adults (>18 years) with at least one imaging modality performed, followed from admission until discharge and/or in-hospital death, were included. Results: We studied 1,435 hospitalized patients (64% males) with a median age of 58 years classified into three regions: Mexico (Mx), 262; Central America and Caribbean (CAC), 428; and South America (SAm), 745. More frequent comorbidities were overweight/obesity, hypertension, and diabetes. During hospitalization, 58% were admitted to the ICU. The in-hospital mortality was 28%, and it was highest in Mx (37%).The most frequent images performed were cCT (61%), mostly in Mx and SAm, and cX-ray (46%), significant in CAC. The cEcho was carried out in 18%, similarly among regions, and LUS was carried out in 7%, with a higher frequently in Mx. Abnormal findings on the cX-ray were peripheral or basal infiltrates, and in cCT abnormal findings were the ground glass infiltrates, more commonly in Mx. In LUS, interstitial syndrome was the most abnormal finding, predominantly in Mx and CAC.Renal failure was the most prevalent complication (20%), predominant in Mx and SAm. Heart failure developed in 13%, predominant in Mx and CAC. Lung thromboembolism was higher in Mx while myocardial infarction was in CAC.Logistic regression showed associations of abnormal imaging findings and their severity, with comorbidities, complications, and evolution. Conclusions: The use and findings of cardiopulmonary imaging in LATAM varied between regions and had a great impact on diagnosis and prognosis.

L-Arginine Ameliorates Defective Autophagy in GM2 Gangliosidoses by mTOR Modulation.

AIMS: Tay-Sachs and Sandhoff diseases (GM2 gangliosidosis) are autosomal recessive disorders of lysosomal function that cause progressive neurodegeneration in infants and young children. Impaired hydrolysis catalysed by ß-hexosaminidase A (HexA) leads to the accumulation of GM2 ganglioside in neuronal lysosomes. Despite the storage phenotype, the role of autophagy and its regulation by mTOR has yet to be explored in the neuropathogenesis. Accordingly, we investigated the effects on autophagy and lysosomal integrity using skin fibroblasts obtained from patients with Tay-Sachs and Sandhoff diseases. RESULTS: Pathological autophagosomes with impaired autophagic flux, an abnormality confirmed by electron microscopy and biochemical studies revealing the accelerated release of mature cathepsins and HexA into the cytosol, indicating increased lysosomal permeability. GM2 fibroblasts showed diminished mTOR signalling with reduced basal mTOR activity. Accordingly, provision of a positive nutrient signal by L-arginine supplementation partially restored mTOR activity and ameliorated the cytopathological abnormalities. INNOVATION: Our data provide a novel molecular mechanism underlying GM2 gangliosidosis. Impaired autophagy caused by insufficient lysosomal function might represent a new therapeutic target for these diseases. CONCLUSIONS: We contend that the expression of autophagy/lysosome/mTOR-associated molecules may prove useful peripheral biomarkers for facile monitoring of treatment of GM2 gangliosidosis and neurodegenerative disorders that affect the lysosomal function and disrupt autophagy.

An (R)-Selective Transaminase From Thermomyces stellatus: Stabilizing the Tetrameric Form.

The identification and 3D structural characterization of a homolog of the (R)-selective transaminase (RTA) from Aspergillus terreus (AtRTA), from the thermotolerant fungus Thermomyces stellatus (TsRTA) is here reported. The thermostability of TsRTA (40% retained activity after 7 days at 40°C) was initially attributed to its tetrameric form in solution, however subsequent studies of AtRTA revealed it also exists predominantly as a tetramer yet, at 40°C, it is inactivated within 48 h. The engineering of a cysteine residue to promote disulfide bond formation across the dimer-dimer interface stabilized both enzymes, with TsRTA_G205C retaining almost full activity after incubation at 50°C for 7 days. Thus, the role of this mutation was elucidated and the importance of stabilizing the tetramer for overall stability of RTAs is highlighted. TsRTA accepts the common amine donors (R)-methylbenzylamine, isopropylamine, and d-alanine as well as aromatic and aliphatic ketones and aldehydes.

Effects of Dog-Based Animal-Assisted Interventions in Prison Population: A Systematic Review.

BACKGROUND: Animal-assisted interventions, in concrete dog-assisted intervention, have been introduced in prisons to reduce recidivism as well as to improve the well-being of prisoners. Therefore, the aim of the present systematic review is to provide an up-to-date analysis of the research on the effects of dog-based animal-assisted therapy in prison population. METHODS: An electronic search of the literature was performed, and 20 articles were included. The PRISMA guideline methodology was employed. RESULTS: Included studies involved a total of 1577 participants. The vast majority of protocols included activities related with dog training, dog caring, or activities, which included vocational or educational components. Duration of dog-based therapies ranged between 60 and 120 min, with the frequency being between 1 and 3 days/week. Statistically significant improvements in prisoners were observed in 13 studies. CONCLUSIONS: Dog-based animal-assisted therapy may improve anxiety, stress, recidivism, and other social variables in male or female inmates.