RESUMO
Bovine cervical mucus (BCM) is important for selection and transport of spermatozoa. When air-dried, BCM obtained at oestrus exhibits arborescent crystallizations, among other arrangements. Considering the relevant endocrine and reproductive information indirectly obtained from BCM crystallization, a morphological investigation was carried out to study its crystalline patterns. BCM samples were collected from healthy Holstein Friesian heifers at oestrus, their crystalline patterns photographed and its morphology analyzed. The majority of the crystallizations obtained showed the typical tree-like patterns reported for BCM. However, a highly symmetrical arrangement was found, characterized by a star-like morphology with six straight, highly defined axes that protrude from the same central point, forming 60º angles. In terms of current knowledge, this short report is the first to show this crystallization geometry in BCM, which, additionally, is remarkably similar to P6B mucus reported for periovulatory human cervical mucus. Even though the role of mucus presenting this type of crystallization is as yet unknown for bovines, its possible functions are also briefly discussed here.
El moco cervical bovino es importante para la selección y el transporte espermático. El moco, obtenido durante el estro y secado al aire, exhibe cristalizaciones con formas principalmente arborescentes. Considerando la importante información endocrina y reproductiva que es posible obtener a partir de la cristalización del moco cervical, se efectuó una investigación morfológica con el propósito de estudiar sus patrones cristalinos. Las muestras de moco se obtuvieron de novillas Holstein Friesian en estro; posteriormente, los patrones de cristalización del moco fueron fotografiados para finalmente analizar su morfología. Las cristalizaciones obtenidas correspondieron a típicos patrones arboriformes previamente reportados. Sin embargo, lo que llamó la atención fue el hallazgo de un arreglo altamente simétrico en una novilla, caracterizado por una morfología similar a estrella con seis ejes rectos, bien definidos, que surgen desde el mismo punto central y forman ángulos de 60º. Según nuestro conocimiento, esta comunicación breve reporta por primera vez la presencia de dicha geometría de cristalización en vaquillas, la cual es muy semejante al patrón cristalino subtipo P6 reportado para el moco cervical perioBvulatorio humano. Si bien el rol ejercido por este tipo de cristalización de moco aún se desconoce en bovinos, se discuten aquí sus posibles funciones.
RESUMO
Chlorhexidine (Cx) augmented with beta-cyclodextrin (β-cd) inclusion compounds, termed Cx:β-cd complexes, have been developed for use as antiseptic agents. The aim of this study was to examine the interactions of Cx:β-cd complexes, prepared at different molecular ratios, with sterol and yeast membranes. The Minimal Inhibitory Concentration (MIC) against the yeast Candida albicans (C.a.) was determined for each complex; the MICs were found to range from 0.5 to 2 µg/mL. To confirm the MIC data, quantitative analysis of viable cells was performed using trypan blue staining. Mechanistic characterization of the interactions that the Cx:β-cd complexes have with the yeast membrane and assessment of membrane morphology following exposure to Cx:β-cd complexes were performed using Sterol Quantification Method analysis (SQM) and scanning electron microscopy (SEM). SQM revealed that sterol extraction increased with increasing β-cd concentrations (1.71 × 10³; 1.4 × 10³; 3.45 × 10³, and 3.74 × 10³ CFU for 1:1, 1:2, 1:3, and 1:4, respectively), likely as a consequence of membrane ergosterol solubilization. SEM images demonstrated that cell membrane damage is a visible and significant mechanism that contributes to the antimicrobial effects of Cx:β-cd complexes. Cell disorganization increased significantly as the proportion of β-cyclodextrin present in the complex increased. Morphology of cells exposed to complexes with 1:3 and 1:4 molar ratios of Cx:β-cd were observed to have large aggregates mixed with yeast remains, representing more membrane disruption than that observed in cells treated with Cx alone. In conclusion, nanoaggregates of Cx:β-cd complexes block yeast growth via ergosterol extraction, permeabilizing the membrane by creating cluster-like structures within the cell membrane, possibly due to high amounts of hydrogen bonding.