Lipases are enzymes that catalyze the hydrolysis of carboxylic esters at a lipid–water interface and are able to catalyze reactions such as alcoholysis, esterification, transesterification, and enantioselective synthesis in organic media. They are important biocatalysts for biotechnological and industrial applications—such as in the food and flavor industry—and in the production of biopharmaceuticals, biofuels, biopolymers, and detergents. A desirable property of lipases is stereoselectivity for the production of chemicals with high optical purity. In this work, we report the improvement of the enantioselective capabilities of the Geobacillus thermoleovorans CCR11 lipase. By means of a rational design and bioinformatic approaches, six amino acids of the catalytic cavity of the lipase LipTioCCR11 were substituted resulting in an increase in the optimum temperature of the enzyme and in the resistance to the presence of organic solvents in hydrolytic reactions, and in the promotion of the enantioselective recognition of R isomers of carboxylic acids with importance for the pharmaceutical and food industries.

Immobilization of enzymes has many advantages for their application in biotechnological processes. In particular, the cross-linked enzyme aggregates (CLEAs) allow the production of solid biocatalysts with a high enzymatic loading and the advantage of obtaining derivatives with high stability at low cost. The purpose of this study was to produce cross-linked enzymatic aggregates (CLEAs) of LipMatCCR11, a 43 kDa recombinant solvent-tolerant thermoalkaliphilic lipase from Geobacillus thermoleovorans CCR11. LipMatCCR11-CLEAs were prepared using (NH₄)₂SO₄ (40% w/v) as precipitant agent and glutaraldehyde (40 mM) as cross-linker, at pH 9, 20 °C. A U₁₀(5⁶) uniform design was used to optimize CLEA production, varying protein concentration, ammonium sulfate %, pH, glutaraldehyde concentration, temperature, and incubation time. The synthesized CLEAs were also analyzed using scanning electron microscopy (SEM) that showed individual particles of <1 µm grouped to form a superstructure. The cross-linked aggregates showed a maximum mass activity of 7750 U/g at 40 °C and pH 8 and retained more than 20% activity at 100 °C. Greater thermostability, resistance to alkaline conditions and the presence of organic solvents, and better durability during storage were observed for LipMatCCR11-CLEAs in comparison with the soluble enzyme. LipMatCCR11-CLEAs presented good reusability by conserving 40% of their initial activity after 9 cycles of reuse.

The Trypanosomatidae family encompasses around 24 genera of unicellular protozoans, many of which are transmitted by various hematophagous arthropods, particularly members of the Orders Diptera and Hemiptera. Fleas and ticks—an understudied group of ectoparasites—have been shown to be hosts of a wide and crescent variety of trypanosomatid species. Further, fleas and ticks of companion animals have been particularly neglected in trypanosomatid surveillance despite the proximity to human populations and the anthropophagous habits of many of these arthropods, which can potentially act as vectors of zoonotic trypanosomatids. We aimed to identify the presence, characterize the species, and establish the prevalence of Kinetoplastids, including members of the Trypanosomatidae family, in ectoparasites collected from dogs and humans from Mexico. A total of 537 ectoparasite specimens belonging to six ectoparasite taxa (Amblyomma mixtum, A. tenellum, Ctenocephalides felis felis, Pulex simulans, Rhipicephalus linnaei, and Rh. sanguineus s.s.) were collected from 15 States of Mexico. An 800 bp fragment of the 18S-rDNA gene from kinetoplastids was amplified and sequenced. The presence of two agents (Trypanosoma caninum and Parabodo sp.) was detected in R. linnaei ticks and one (Blechomonas lauriereadi) in the cat flea Ct. felis felis. This is the first record of genetic material of kinetoplastid species in ectoparasites from dogs and humans in Mexico.

Rhipicephalus (Boophilus) microplus is a leading cause of significant economic losses in the livestock industry, and tick populations have developed multiple forms of resistance to acaricides; therefore, the potential of novel natural bioactive compounds that are effective for targeting ticks must be addressed. The aim of this study was to evaluate the acaricidal and anticholinesterase activities of R. aculeata seeds and to identify naturally occurring compounds that potentially inhibit anticholinesterase through in silico docking. The acaricidal activity of the extract of R. aculeata seeds against larval and adult R. microplus ticks was assessed through immersion tests. Inhibition of anticholinesterase activity was measured spectrophotometrically. Extracts of R. aculeata seeds showed activity against larvae and engorged females of R. microplus, and a reduction in the reproductive index were also observed. Rutin, chlorogenic acid, quercetin, and epicatechin exhibited noteworthy interactions with the active site residues of RmAChE. These findings could significantly contribute to the exploration of novel natural products that can potentially inhibit RmAChE and could be used in the development of new acaricides for tick control.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae pose a significant public health risk. As zoos grow in popularity, exotic animals come into closer contact with humans, making them potential reservoirs of ESBLs. However, data on ESBL presence in Mexican zoos remains limited. For this reason, this study aimed to isolate and assess the antimicrobial susceptibility of Enterobacteriaceae that colonize avian species in a petting zoo and to identify any ESBL-producing isolates. Cloacal swabs were collected from 34 healthy birds at Miguel Angel de Quevedo Zoo, Veracruz, Mexico. Samples were analyzed microbiologically and molecularly to detect ESBL-encoding genes. A total of seventeen E. coli and one K. pneumoniae strains were isolated from cloacal swabs of bird species, and multidrug resistance (MDR) was found. The most frequently detected genes were bla_CTX-M-1 (16/18) and bla_TEM-1 (12/18). The detection of multidrug-resistant (MDR) strains carrying bla_CTX-M-1, bla_TEM-1, and bla_SHV genes highlights the potential role of birds as reservoirs and disseminators of antimicrobial resistance (AMR) in urban environments. To the best of our knowledge, this is the first study conducted in Mexico. In conclusion, MDR ESBL-producing bacteria were found in the fecal microbiota of bird species at a petting zoo in Mexico. The limitations of this study emphasize the need for a One Health approach to analyze the genome-wide isolates and epidemiology of antimicrobial-resistant bacteria in captive zoo animals in Mexico. This would support targeted surveillance efforts and help reduce the emergence and spread of resistant bacteria among zoo animals and visitors.