This article reports the study of the structural elements of bovine vaginal fluid at oestrus using a confocal scanning laser microscope (CSLM) to examine samples collected from 10 lactating cows at the time of insemination. The filamentous glycoproteins, which form the structural component of vaginal fluid, were stained with fluorophore acridine orange for 10 min. This microscopy technique permits visualization of a network of non-oriented filaments of different thickness in a three-dimensional array. This arrangement was repeated throughout the sample and was common to all samples. Interfilament spaces varied in width between cows and ranged from 1 to 20 microns. The present results provide a new, non-aggressive technique for the study of biological samples that show hydrogel-like behaviour. Due to its simplicity, the CSLM technique proposed offers the advantages of (1) providing realistic images of vaginal fluid structure, free from artifacts arising from sample preparation, and (2) the possibility of observing specimens shortly after collection. CSLM proved to be a useful tool for the examination of vaginal fluid and may also serve as a good control for artifacts associated with scanning electron microscopy procedures.

A consortium of microorganisms with the capacity to degrade crude oil has been characterized by means of confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The analysis using CLSM shows that Microcoleus chthonoplastes is the dominant organism in the consortium. This cyanobacterium forms long filaments that group together in bundles inside a mucopolysaccharide sheath. Scanning electron microscopy and transmission electron microscopy have allowed us to demonstrate that this cyanobacterium forms a consortium primarily with three morphotypes of the heterotrophic microorganisms found in the Microcoleus chthonoplastes sheath. The optimal growth of Microcoleus consortium was obtained in presence of light and crude oil, and under anaerobic conditions. When grown in agar plate, only one type of colony (green and filamentous) was observed.

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Summary A simple method for handling individual specimens that must be processed either for scanning or transmission electron microscopy studies is described. For scanning microscope processing, dehydration is carried out with samples enclosed in small cages made from TAAB capsules in which top and bottom are substituted by plankton nets, and for transmission electron microscopy, samples are pre‐embedded in agarose. This procedure significantly reduces mouth pipetting, dissecting microscope observations, is less labour intensive and, most importantly, reduces sample loss.