In this research, we evaluated the effects of different frequencies (25 and 45 kHz) and times (15 and 30 min) of high-intensity ultrasound (HIU) applied to fresh raw milk on the textural properties of Oaxaca cheese. When HIU was applied for 15 min, the cheese melting time was reduced by up to 23.4 s compared to the control. The cheeses produced with ultrasonicated milk at 45 kHz presented larger melting and exudate areas. They were softer, but consumer acceptability was lower. Frequencies of 25 and 45 kHz (15 or 30 min) reduced the temperature of the solid–liquid transition by 1.9–3.6 °C and 0.6–1.8 °C, respectively, compared to controls. Consequently, the melting time in ultrasonicated cheese was significantly reduced. The strands were perfectly aligned and well organized in the direction of stretching with 25 kHz ultrasonication. In addition, these cheeses were more consistent, chewy, and rubbery. Consequently, they were preferred and more accepted in flavor, aroma, and texture, with high general acceptability. HIU is a promising technology to improve the textural and rheological properties of Oaxaca cheese made with raw milk, as HIU produced cheeses with better sensory acceptability by consumers and with a high melting capacity and thread formation.

The search for developing materials of natural origin has become imperative due to the resistance shown by phytopathogenic microorganisms to traditional antimicrobial agents. Natural polymers such as chitosan offer a new alternative to fungal infections because, in most cases, these polymers are biocompatible, nontoxic, and natural. This study aimed to synthesize nanochitosan using ultrasonication and evaluate its antifungal activity on Colletotrichum chrysophillum and Colletotrichum musae. Nanochitosan of 302.4 ± 92.3 nm and a zeta potential of +35.9 ± 2.3 Mv, amorphous in shape, and a rough surface, was obtained. Nanochitosan reduced the radial growth 21%, for C. chrysophillum while C. musae showed a maximum inhibition of 26% at a concentration of 1.5 mg mL⁻¹ of nanochitosan. C. musae was the species most affected, with a 38% increase in hyphal diameter to 12 h. Also, nanochitosan affected the integrity of the fungi cell walls, plasma membrane, and generated low oxidative stress level. Our findings indicate that nanochitosan induces notable changes in the intracellular structures of the tested phytopathogens. Nevertheless, additional investigations are required to clarify the mechanisms underlying adaptability or resistance in fungal strains that exhibit reduced sensitivity to this biopolymer.

This research evaluated two methods of arginine encapsulation, melt emulsification and nanoprecipitation, using a lipid matrix of carnauba wax and commercial polymers (Eudragit^®) as a protective material. The ratios of wax–arginine were 1:1, 2:1, 3:1, and 4:1, while those of Eudragit^® RS:RL were 30:70 and 40:60 in proportions of 1:0.5 and 1:1 Eudragit^®–arginine. The microcapsules were morphostructurally characterized by scanning electron microscopy, and a microelement analysis was performed via energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Additionally, in vitro digestibility was used to determine the protection efficiency. Both encapsulated systems presented regular (crystals) and spherical (microcapsules) polyhedral morphologies. Qualitative nitrogen decreased significantly as the wax ratio increased in the wax–arginine formulations. The formulations with a 1:1 Eudragit:–arginine ratio (1000 mg arginine) produced a higher nitrogen content in the encapsulated systems than the formulations containing 500 mg of arginine. The 2:1 and 3:1 wax–arginine formulations had the lowest degradability after 5 h of rumen fluid exposure (40.7 and 21.26%, respectively) in comparison with 100% unencapsulated arginine. The 3:1 wax–arginine formulation is an efficient encapsulating system which protects against rumen degradation. The more intense absorption bands at 1738 cm⁻¹ and 1468 cm⁻¹ associated with the C=O and C-H groups in carnauba wax indicate that arginine was more protected than in the other systems.

Hemileia vastatrix coffee leaf rust reduces Mexican coffee production by 51%. We aimed to analyze the size and distribution of H. vastatrix urediniospores among coffee plantations, as well as the morphological structures of the uredinium. In 2015, 65 leaf samples with rust symptoms were collected from 17 coffee cultivars grown at various altitudes (229–1649 m) under different environmental conditions in 14 regions of four Mexican states. A total of 30 spores per sample were measured and grouped using the Ward centroid method, and the group distribution was analyzed. Uredinia morphology was examined via electron microscopy, and the identity of the rust was confirmed. We identified eight significant spore groups. Groups 8h and 3a had the smallest and largest spores, respectively, which were distributed in two and one state, respectively, at different altitudes. The spores in groups 1b–7f were variable within the intermediate size range, and their distribution was at least one group per state under temperate, warm, and humid conditions. The uredinium had double-cell walls in the pedicels and urediniospores, a split septum, spores with hilum and protuberances, and an oval spore shape; anastomosis was detected on vegetative hyphae and haustoria. These findings may reflect gaps in knowledge in the biological cycle of this rust.

Because blackberries (Rubus spp.) are commercially important in Mexico, monitoring of wild plants (Rydberg 1963) can be valuable for management of disease. In April 14, 2024, and May 19, 2025 galls were observed (~16% incidence) on stems of wild blackberries (Rubus aff. miser Liebm.) near Venta Grande, municipality of Huauchinango, Puebla, Mexico (20.132 N, 98.083 W; 19.994 N, 97.987 W; ca. 2000 m). Galls were rounded, brown to blackish in color, with a woody texture and covered with yellow spores of a rust fungus. Galls on herbaceous stems measured 0.5–4.0 × 0.7–3.5 cm; on woody stems forming dense clusters of up to 31.0 × 7.5 × 5.0 cm. No rust was observed on leaves, petioles, or flowers. Some galls showed up to 90% rust severity. The galls were examined under a stereomicroscope up to 6.3X. Histological sections were prepared, mounted in 85% lactic acid and observed using light, Nomarski, and phase-contrast microscopy (µm measured at 100X); scanning electron microscopy sections were also examined. In all galls examined, uredinoid aecia were produced, but no spermogonia, uredinia, or telia. Sori were superficial, globose to elongated, 1.0–2.0 mm long, pale yellowish to brown, of subepidermal origin, erupting with a powdery appearance, and opening longitudinally with persistent brown epidermal remnants. Aeciospores were hyaline to pale yellow; borne in chains without intercalated cells; some with colorless pedicels, 67.5–100.0 × 5.0 µm long; ellipsoidal to subglobose, occasionally slightly obovoid, globoid, or cylindrical, measuring (17–)20–24(–25) × 22–30(–35) µm (n = 100); spore wall hyaline, 1.0–1.5 (–2.0) µm thick; uniformly echinulate, ornaments 1.15–1.61 × 1.06–1.35 µm. Rarely, spores had two equatorial germ pores. Peridia and paraphyses were not observed. DNA was extracted from spores using the CTAB 2% method (Doyle and Doyle 1987), and a portion of the rDNA repeat spanning the ITS2–28S was amplified and sequenced (Kaishian et al. 2024) with Rust2INV/LR6 and LROR/LR3 primers (Aime 2006). Maximum Likelihood analyses were performed in Iqtree v.1.6.12 and Bayesian inference in MrBayes (Ronquist et al. 2012; Nguyen et al. 2015). The rust was identified as Kuehneola guatemalensis Cummins, a species lacking publicly available sequence data. In Guatemala, K. guatemalensis forms galls on the stems of Rubus sapidus Schltdl. (syn. R. tuerckheimii Rydb., Cummins 1943). The sequence (NCBI PX692954) is congeneric with the gall-forming K. loeseneriana (sharing 95.5% identity) from Rubus humistratus (Hernández and Hennen 2003) which differs from K. guatemalensis in producing aeciospores and urediniospores in the spirally striated arrangement of ornamentation and with K. uredinis (91.5% identity), which only infects leaves and does not form galls (Hernández and Hennen 2003). The specimen was deposited in the CMPH Herbarium (Accessions 3826 and 3827) and the host specimen in the CHAPA Herbarium (Accession 159034). Although we located two herbarium specimens (PUR58566 and PURN6644 from 1963 and 1974, Oaxaca and Veracruz states, on Rubus sp.) of K. guatemalensis from Mexico, this is the first report of K. guatemalensis on R. aff. miser and the first published record in Mexico. This study will aid blackberry producers to proactively monitor for symptoms of K. guatemalensis in their crops.