Nutritional imbalances in a Mexican vegan group: urgent need for country-specific dietary guidelines.

Introduction: Introduction: vegan diets exclude the consumption of animal-derived products, and health advantages have been reported when followed. However, heterogeneous eating habits, food availability, and sociocultural characteristics among regions could lead to different physiological results. Case reports: twelve patients following a strict vegan diet for an uninterrupted period of ≥ 3 years were subjected to clinical assessment. Patients significantly exceeded the suggested intake for sugar, presented six mineral deficiencies, and exhibited three vitamins below the recommended consumption. We further identified hyperglycemia, hypertriglyceridemia, subnormal serum vitamin B12 concentrations, as well as macrocytosis and microcytic anemia in several participants. Discussion: this Mexican vegan diet is strongly influenced by endemic and cultural adaptations that could limit the benefits reported in other populations. Professional guidance is required to avoid specific deficiencies with potential repercussions. We urge country-specific vegan guidelines considering local eating habits, food availability, and sociocultural perspectives around food.

Introducción: Introducción: la dieta vegana excluye el consumo de productos de origen animal y se ha vinculado con una disminución del riesgo de morbimortalidad. Sin embargo, los distintos hábitos alimentarios entre países podrían condicionar los beneficios reportados para las dietas basadas en vegetales. Casos clínicos: doce pacientes siguiendo una estricta dieta vegana por ≥ 3 años se sometieron a una evaluación clínica. Exhibieron una ingestión de azúcar que supera el consumo sugerido, presentaron tres deficiencias vitamínicas y seis de minerales. Se identificó la presencia de hiperglucemia, hipertrigliceridemia, concentraciones séricas subnormales de vitamina B12, macrocitosis y anemia microcítica en varios participantes. Discusión: la dieta vegana de este grupo resultó fuertemente influenciada por adaptaciones culturales que podrían limitar los beneficios reportados en otras poblaciones. Se requiere orientación profesional para evitar desequilibrios nutricionales. Enfatizamos la necesidad del desarrollo de guías alimentarias y de práctica clínica que consideren los hábitos alimentarios locales, la disponibilidad de alimentos en la región y las perspectivas socioculturales en torno a la dieta vegana.

Identification of L-asparaginases from Streptomyces strains with competitive activity and immunogenic profiles: a bioinformatic approach.

The enzyme L-asparaginase from Escherichia coli is a therapeutic enzyme that has been a cornerstone in the clinical treatment of acute lymphoblastic leukemia for the last decades. However, treatment effectiveness is limited by the highly immunogenic nature of the protein and its cross-reactivity towards L-glutamine. In this work, a bioinformatic approach was used to identify, select and computationally characterize L-asparaginases from Streptomyces through sequence-based screening analyses, immunoinformatics, homology modeling, and molecular docking studies. Based on its predicted low immunogenicity and excellent enzymatic activity, we selected a previously uncharacterized L-asparaginase from Streptomyces scabrisporus. Furthermore, two putative asparaginase binding sites were identified and a 3D model is proposed. These promising features allow us to propose L-asparaginase from S. scabrisporus as an alternative for the treatment of acute lymphocytic leukemia.

Identification of the σ7°-Dependent Promoter Controlling Expression of the ansPAB Operon of the Nitrogen-Fixing Bacterium Rhizobium etli.

The aim of the present work was to examine the putative promoter region of the operon ansPAB and to determine the general elements required for the regulation of transcriptional activity. The transcriptional start site of the ansPAB promoter was determined by using highresolution S1-nuclease mapping. Sequence analysis of this region showed -10 and -35 elements, which were consistent with consensus sequences for R. etli promoters that are recognized by the major form of RNA polymerase containing the σ(70) transcription factor. Mutation studies affecting several regions located upstream of the transcriptional start site confirmed the importance of these elements on transcriptional expression.

Rhizobium etli asparaginase II: an alternative for acute lymphoblastic leukemia (ALL) treatment.

Bacterial L-asparaginase has been a universal component of therapies for childhood acute lymphoblastic leukemia since the 1970s. Two principal enzymes derived from Escherichia coli and Erwinia chrysanthemi are the only options clinically approved to date. We recently reported a study of recombinant L-asparaginase (AnsA) from Rhizobium etli and described an increasing type of AnsA family members. Sequence analysis revealed four conserved motifs with notable differences with respect to the conserved regions of amino acid sequences of type I and type II L-asparaginases, particularly in comparison with therapeutic enzymes from E. coli and E. chrysanthemi. These differences suggested a distinct immunological specificity. Here, we report an in silico analysis that revealed immunogenic determinants of AnsA. Also, we used an extensive approach to compare the crystal structures of E. coli and E. chrysantemi asparaginases with a computational model of AnsA and identified immunogenic epitopes. A three-dimensional model of AsnA revealed, as expected based on sequence dissimilarities, completely different folding and different immunogenic epitopes. This approach could be very useful in transcending the problem of immunogenicity in two major ways: by chemical modifications of epitopes to reduce drug immunogenicity, and by site-directed mutagenesis of amino acid residues to diminish immunogenicity without reduction of enzymatic activity.

Biochemical characterization of recombinant L-asparaginase (AnsA) from Rhizobium etli, a member of an increasing rhizobial-type family of L-asparaginases.

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters K(m), V(max), and k(cat) for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at 50 degrees C, but the optimal temperature of activity was 37 degrees C. It also showed maximal and optimal activities at pH 9.0. The values of K(m), V(max), k(cat), and k(cat)/K(m) were 8.9 +/- 0.967 × 10⁻³ M, 128 +/- 2.8 U/mg protein, 106 +/- 2 s⁻¹, and 1.2 +/- 0.105 × 104 M⁻¹s⁻¹, respectively. The L-asparaginase activity was reduced in the presence of Mn²âº, Zn²âº, Ca²âº, and Mg²âº metal ions for about 52% to 31%. In addition, we found that NH4⁺, L-Asp, D-Asn, and beta-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobialtype asparaginase II family.