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Lipases are used in many food, energy, and pharmaceutical processes. Thus, new systems have been sought to synthesize alternative lipases with potential biotechnological applications. Kluyveromyces marxianus is a yeast with recognized lipase activity; at least ten putative lipases/esterases in its genome have been detected, and two of them possess a signal peptide for extracellular secretion. The study of extracellular lipases becomes more relevant since they usually have higher activity rates than intracellular lipases and simpler purification mechanisms. For these reasons, this study aimed to characterize the production and lipase activity of the putative extracellular lipases of the K. marxianus L-2029 strain, encoded in the genes LIP3 and YJR107W. Both genes were heterologously expressed in Saccharomyces cerevisiae BY4742 (yeast strain without extracellular lipase activity) using a pYES2.1/V5-His-TOPO® plasmid. Herein, we show evidence that the strain transformed with the LIP3 gene did not show lipase activity during flask galactose induction. On the other hand, the strain transformed with the YJR107W gene showed a specific activity of 0.397 U/mg, with an optimum temperature of 37 °C and pH 6. For maximum cell production, glucose and yeast extract concentrations were evaluated by a 22 factorial design, followed by the validation of the best concentrations predicted by a statistical model; a 22 factorial design was also carried out to evaluate the concentration of the inducer galactose on the transformed strains, and the intracellular and extracellular lipase specific activities were quantified. Finally, the biomass and lipase production were determined for each strain, which was grown in a stirred tank bioreactor with a working volume of 1.5 L. The specific activities of the transformed strains obtained in the bioreactor were 1.36 U/mg for the LIP3 transformant and 1.25 U/mg for the YJR107W transformant, respectively.

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In this work, the leaves of K. tomentosa were macerated with hexane, chloroform, and methanol, respectively. The phytochemical profiles of hexane and chloroform extracts were unveiled using GC/MS, whereas the chemical composition of the methanol extract was analyzed using UPLC/MS/MS. The antibacterial activity of extracts was determined against gram-positive and gram-negative strains through the minimal inhibitory concentration assay, and in silico studies were implemented to analyze the interaction of phytoconstituents with bacterial peptides. The antioxidant property of extracts was assessed by evaluating their capacity to scavenge DPPH, ABTS, and H2O2 radicals. The toxicity of the extracts was recorded against Artemia salina nauplii and Caenorhabditis elegans nematodes. Results demonstrate that the hexane and chloroform extracts contain phytosterols, triterpenes, and fatty acids, whereas the methanol extract possesses glycosidic derivatives of quercetin and kaempferol together with sesquiterpene lactones. The antibacterial performance of extracts against the cultured strains was appraised as weak due to their MIC90 values (>500 µg/mL). As antioxidants, treatment with extracts executed high and moderate antioxidant activities within the range of 50-300 µg/mL. Extracts did not decrease the viability of A. salina, but they exerted a high toxic effect against C. elegans during exposure to treatment. Through in silico modeling, it was recorded that the flavonoids contained in the methanol extract can hamper the interaction of the NAM/NAG peptide, which is of great interest since it determines the formation of the peptide wall of gram-positive bacteria. This study reports for the first time the biological activities and phytochemical content of extracts from K. tomentosa and proposes a possible antibacterial mechanism of glycosidic derivatives of flavonoids against gram-positive bacteria.

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The insecticidal property of ring C-seco limonoids has been discovered empirically and the target protein identified, but, to date, the molecular mechanism of action has not been described at the atomic scale. We elucidate on computational grounds whether nine C-seco limonoids present sufficiently high affinity to bind specifically with the putative target enzyme of the insects (ecdysone 20-monooxygenase). To this end, 3D models of ligands and the receptor target were generated and their interaction energies estimated by docking simulations. As a proof of concept, the tetrahydro-isoquinolinyl propenamide derivative QHC is the reference ligand bound to aldosterone synthase in the complex with PDB entry 4ZGX. It served as the 3D template for target modeling via homology. QHC was successfully docked back to its crystal pose in a one-digit nanomolar range. The reported experimental binding affinities span over the nanomolar to lower micromolar range. All nine limonoids were found with strong affinities in the range of -9 < ΔG < -13 kcal/mol. The molt hormone ecdysone showed a comparable ΔG energy of -12 kcal/mol, whereas -11 kcal/mol was the back docking result for the liganded crystal 4ZGX. In conclusion, the nine C-seco limonoids were strong binders on theoretical grounds in an activity range between a ten-fold lower to a ten-fold higher concentration level than insecticide ecdysone with its known target receptor. The comparable or even stronger binding hints at ecdysone 20-monooxygenase as their target biomolecule. Our assumption, however, is in need of future experimental confirmation before conclusions with certainty can be drawn about the true molecular mechanism of action for the C-seco limonoids under scrutiny.

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Polyethylene (PE) is one of the most highly consumed petroleum-based polymers and its accumulation as waste causes environmental pollution. In this sense, the use of microorganisms and their enzymes represents the most ecofriendly and effective decontamination approach. In this work, molecular docking simulation for catalytic enzyme degradation of PE was carried out using individual enzymes: laccase (Lac), manganese peroxidase (MnP), lignin peroxidase (LiP) and unspecific peroxygenase (UnP). PE-binding energy, PE-binding affinity and dimensions of PE-binding sites in the enzyme cavity were calculated in each case. Four hypothetical PE biodegradation pathways were proposed using individual enzymes, and one pathway was proposed using a synergic enzyme combination. These results show that in nature, enzymes act in a synergic manner, using their specific features to undertake an extraordinarily effective sequential catalytic process for organopollutants degradation. In this process, Lac (oxidase) is crucial to provide hydrogen peroxide to the medium to ensure pollutant breakdown. UnP is a versatile enzyme that offers a promising practical application for the degradation of PE and other pollutants due to its cavity features. This is the first in silico report of PE enzymatic degradation, showing the mode of interaction of PE with enzymes as well as the degradation mechanism.

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Lipases are hydrolytic enzymes that break the ester bonds of triglycerides, generating free fatty acids and glycerol. Extracellular lipase activity has been reported for the nonconventional yeast Kluyveromyces marxianus, grown in olive oil as a substrate, and the presence of at least eight putative lipases has been detected in its genome. However, to date, there is no experimental evidence on the physiological role of the putative lipases nor their structural and catalytic properties. In this study, a bioinformatic analysis of the genes of the putative lipases from K. marxianus L-2029 was performed, particularly identifying and characterizing the extracellular expected enzymes, due to their biotechnological relevance. The amino acid sequence of 10 putative lipases, obtained by in silico translation, ranged between 389 and 773 amino acids. Two of the analysed putative proteins showed a signal peptide, 25 and 33 amino acids long for KmYJR107Wp and KmLIP3p, and a molecular weight of 44.53 and 58.23 kDa, respectively. The amino acid alignment of KmLIP3p and KmYJR107Wp with the crystallized lipases from a patatin and the YlLip2 lipase from Yarrowia lipolytica, respectively, revealed the presence of the hydrolase characteristic motifs. From the 3D models of putative extracellular K. marxianus L-2029 lipases, the conserved pentapeptide of each was determined, being GTSMG for KmLIP3p and GHSLG for KmYJR107Wp; besides, the genes of these two enzymes (LIP3 and YJR107W) are apparently regulated by oleate response elements. The phylogenetic analysis of all K. marxianus lipases revealed evolutionary affinities with lipases from abH15.03, abH23.01, and abH23.02 families.

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La criptorquidia se presenta en el 4% de los recién nacidos y en 1% al año de vida. Las complicaciones de las criptorquidias pueden ser funcionales y/o neoplásicas. Presentamos un caso de un varón de 41 años, que ingreso a la guardia, con dolor abdominal constante y progresivo, con masa visible y palpable de hipocondrio derecho, de 24 hs de evolución. Se realizó ecografía (US) abdominal, seguida de tomografía computada (TC). Se observó una masa de aspecto sólido en hipocondrio derecho en US. En la TC, la formación aparece en el lado izquierdo. Debido al curso del cuadro clínico se decidió intervenir quirúrgicamente. La anatomía patológica informó seminoma clásico intrabdominal en testículo no descendido y sugirió US testicular, la cual confirmó la ausencia del testículo derecho en la bolsa escrotal. Presentamos un caso de criptorquidia de localización intrabdominal, con degeneración en seminoma y torsión de pedículo, lo cual explica el cambio de localización de la formación.

Seminoma in an undescended testis. Cryptorchidism is present in aproximately 4% of full-term new born baby and approximately 1% of infants at 1 year of age. This has significantclinical implications, including sterility and testicular malignancy. We present a 41 year-old man with a 24 hours history of progressive abdominal pain. A right lower-quadrant mass wasobserved during physical examination.An abdominal ultrasound (US) and computed tomographic (CT) exam was performed. US showed a soft-tissue mass on the right side of the patientabdomen, and the CT scans showed the mass on the left side. The patient underwent surgery. Histological analysisrevealed a classic seminoma in an undescended testis. The testis ultrasonography showed absence the right testis. We present a report of a seminoma in an undescended testis,which suffer pedicle torsion and modified their localization in the abdomen.

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Ainda que cada capítulo enfatize certas dimensões específicas, este livro mostra a interdependência e a estreita ligação existente entre os diversos temas. Por exemplo, podemos citar a pobreza e a profunda desigualdade nas oportunidades educativas e o desempenho escolar; o impacto das políticas públicas e a forma com que os governos destinam os recursos públicos para as crianças, os adolescentes e suas famílias, entre outros. O livro também apresenta discussões sobre os círculos perversos que fazem das crianças e adolescentes suas maiores vítimas: família pobre, nível educacional baixo, desemprego e pobreza. A eles se somam e interatuam outros fatores que geram e alimentam esses e outros círculos perversos: falta de acesso a bens e a equipamentos sociais indispensáveis, como saneamento, eletricidade, água potável, cobertura de saúde; a dificuldade de acesso a profissões e/ou rendas estáveis ou minimamente compensadoras, delinquência, discriminações diversas e racismo. (AU).

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Se presentan 19 pacientes con testiculos tumorales estudiados con ecografía (transductor de 5 MHz) y su correspondiente confirmación quirúrgica. La ecografía demostró una alta certeza diagnóstica: 96,8% para determinar la localización de una lesión escrotal (intratesticular, extratesticular o mixta). Frente a las lesiones neoplásicas, el método demostró alta sensibilidad: 100%, baja especificidad: 64%, y 85% de certeza diagnóstica. Se analizan en detalle los signos ultrasonográficos asociados a patología tumoral, así como el origen de los 5 falsos-positivos que disminuyen la especificidad ecográfica

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Se presentan 19 pacientes con testiculos tumorales estudiados con ecografía (transductor de 5 MHz) y su correspondiente confirmación quirúrgica. La ecografía demostró una alta certeza diagnóstica: 96,8% para determinar la localización de una lesión escrotal (intratesticular, extratesticular o mixta). Frente a las lesiones neoplásicas, el método demostró alta sensibilidad: 100%, baja especificidad: 64%, y 85% de certeza diagnóstica. Se analizan en detalle los signos ultrasonográficos asociados a patología tumoral, así como el origen de los 5 falsos-positivos que disminuyen la especificidad ecográfica (AU)

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Se comunica el resultado del tratamiento de colecciones intraabdominales (absceso subfrénico, intrahepático, etc.), por punción percutánea, realizado a 7 pacientes. Se utilizó ecografía como guía, prefiriéndola a la tomografía computada. Estos casos realizados en 6 meses, han sido satisfactorios. No hubo mortalidad ni morbilidad. Se expone el tipo de agujas trocar y drenajes usados. También se comentan hallazgos bacteriológicos

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Se comunica el resultado del tratamiento de colecciones intraabdominales (absceso subfrénico, intrahepático, etc.), por punción percutánea, realizado a 7 pacientes. Se utilizó ecografía como guía, prefiriéndola a la tomografía computada. Estos casos realizados en 6 meses, han sido satisfactorios. No hubo mortalidad ni morbilidad. Se expone el tipo de agujas trocar y drenajes usados. También se comentan hallazgos bacteriológicos (AU)

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