Tunneling Nanotube-like Structures in Giardia duodenalis.

Giardia doudenalis (lamblia, intestinalis) is a protozoan parasite that inhabits the lumen of the upper small intestine of vertebrates, causing chronic abdominal pains and severe diarrhea, symptoms of giardiasis, a persistent and recurrent infection. This characteristic is mainly due to the presence of membrane variant-specific surface proteins (VSPs) that give this parasite the ability to successively infect the host through antigenic variation. Using high-resolution scanning microscopy (HR-SM), we observed the presence, formation, and extension of tunneling-nanotube-like surface structures in Giardia, especially following parasite challenges with VSP antibodies. They were seen all over the parasite surface, both in vitro and in vivo, showing that G. duodenalis nanotube formation occurs in complex environments such as the gut. In addition, we also observed that some of these nanotubes displayed a periodic strangulation that produces 100 nm vesicles that seemed to be released in a process similar to that previously observed in Trypanosoma brucei. The presence of nanotube-like structures in G. duodenalis highlights yet another strategy of cellular communication utilized by these parasites, whether between themselves or with the host cell.

Nanoparticles and plants: A focus on analytical characterization techniques.

Nanotechnology has brought about significant progress through the use of goods based on nanomaterials. However, concerns remain about the accumulation of these materials in the environment and their potential toxicity to living organisms. Plants have the ability to take in nanomaterials (NMs), which can cause changes in their physiology and morphology. On the other hand, nanoparticles (NPs) have been used to increase plant development and control pests in agriculture by including them into agrochemicals. The challenges of the interaction, internalization, and accumulation of NMs within plant tissues are enormous, mainly because of the various characteristics of NMs and the absence of reliable analytical tools. As our knowledge of the interactions between NMs and plant cells expands, we are able to create novel NMs that are tailored, targeted, and designed to be safe, thus minimizing the environmental consequences of nanomaterials. This review provides a thorough examination and comparison of the main microscopy techniques, spectroscopic methods, and far-field super-resolution methodologies used to examine nanomaterials within the cell walls of plants.

Brain Tumor Anatomy with Tractography Fluorescence and Confocal Endoscopy.

Tractography fluorescence and confocal endomicroscopy are complementary technologies to targeted tumor resection, and it is certain that as our technology for fluorescent probes continues to evolve, the confocal microscope will continue to be refined. Recent work suggests that intraoperative high-resolution augmented reality endomicroscopy, a real-time alternative to invasive biopsy and histopathology, has the potential to better quantify tumor burden at the final stages of surgery and ultimately to improve patient outcomes when combined with wide-field imaging approaches. Additional studies are needed to further elucidate the clinical benefits of these new technologies for brain tumor patients.

Characterization of a new extra-axonemal structure in the Giardia intestinalis flagella.

The inner structure of the flagella of Giardia intestinalis is similar to that of other organisms, consisting of nine pairs of outer microtubules and a central pair containing radial spokes. Although the 9+2 axonemal structure is conserved, it is not clear whether subregions, including the transition zone, are present in the flagella of this parasite. Giardia axonemes originate from basal bodies and have a lengthy cytosolic portion before becoming active flagella. The region of the emergence of the flagellum is not accompanied by any membrane specialization, as seen in other protozoa. Although Giardia is an intriguing model of study, few works focused on the ultrastructural analysis of the flagella of this parasite. Here, we analyzed the externalization region of the G. intestinalis flagella using ultra-high resolution scanning microscopy (with electrons and ions), atomic force microscopy in liquid medium, freeze fracture, and electron tomography. Our data show that this region possesses a distinctive morphological feature - it extends outward and takes on a ring-like shape. When the plasma membrane is removed, a structure surrounding the axoneme becomes visible in this region. This new extra-axonemal structure is observed in all pairs of flagella of trophozoites and remains attached to the axoneme even when the interconnections between the axonemal microtubules are disrupted. High-resolution scanning electron microscopy provided insights into the arrangement of this structure, contributing to the characterization of the externalization region of the flagella of this parasite.

What do we know about blood-testis barrier? current understanding of its structure and physiology.

Blood-testis barrier (BTB) creates a particular compartment in the seminiferous epithelium. Contacting Sertoli cell-Sertoli cell plasma membranes possess specialized junction proteins which present a complex dynamic of formation and dismantling. Thus, these specialized structures facilitate germ cell movement across the BTB. Junctions are constantly rearranged during spermatogenesis while the BTB preserves its barrier function. Imaging methods are essential to studying the dynamic of this sophisticated structure in order to understand its functional morphology. Isolated Sertoli cell cultures cannot represent the multiple interactions of the seminiferous epithelium and in situ studies became a fundamental approach to analyze BTB dynamics. In this review, we discuss the contributions of high-resolution microscopy studies to enlarge the body of morphofunctional data to understand the biology of the BTB as a dynamic structure. The first morphological evidence of the BTB was based on a fine structure of the junctions, which was resolved with Transmission Electron Microscopy. The use of conventional Fluorescent Light Microscopy to examine labelled molecules emerged as a fundamental technique for elucidating the precise protein localization at the BTB. Then laser-scanning confocal microscopy allowed the study of three-dimensional structures and complexes at the seminiferous epithelium. Several junction proteins, like the transmembrane, scaffold and signaling proteins, were identified in the testis using traditional animal models. BTB morphology was analyzed in different physiological conditions as the spermatocyte movement during meiosis, testis development, and seasonal spermatogenesis, but also structural elements, proteins, and BTB permeability were studied. Under pathological, pharmacological, or pollutant/toxic conditions, there are significant studies that provide high-resolution images which help to understand the dynamic of the BTB. Notwithstanding the advances, further research using new technologies is required to gain information on the BTB. Super-resolution light microscopy is needed to provide new research with high-quality images of targeted molecules at a nanometer-scale resolution. Finally, we highlight research areas that warrant future studies, pinpointing new microscopy approaches and helping to improve our ability to understand this barrier complexity.