A connectome is not enough – what is still needed to understand the brain of Drosophila?

ABSTRACT Understanding the structure and operation of any nervous system has been a subject of research for well over a century. A near-term opportunity in this quest is to understand the brain of a model species, the fruit fly Drosophila melanogaster. This is an enticing target given its relatively small size (roughly 200,000 neurons), coupled with the behavioral richness that this brain supports, and the wide variety of techniques now available to study both brain and behavior. It is clear that within a few years we will possess a connectome for D. melanogaster: an electron-microscopy-level description of all neurons and their chemical synaptic connections. Given what we will soon have, what we already know and the research that is currently underway, what more do we need to know to enable us to understand the fly's brain? Here, we itemize the data we will need to obtain, collate and organize in order to build an integrated model of the brain of D. melanogaster.

A pH-Adjustable Tissue Clearing Solution That Preserves Lipid Ultrastructures: Suitable Tissue Clearing Method for DDS Evaluation

Visualizing biological events and states to resolve biological questions is challenging. Tissue clearing permits three-dimensional multicolor imaging. Here, we describe a pH-adjustable tissue clearing solution, Seebest (SEE Biological Events and States in Tissues), which preserves lipid ultrastructures at an electron microscopy level. Adoption of polyethylenimine was required for a wide pH range adjustment of the tissue clearing solution. The combination of polyethylenimine and urea had a good tissue clearing ability for multiple tissues within several hours. Blood vessels stained with lipophilic carbocyanine dyes were deeply visible using the solution. Adjusting the pH of the solution was important to maximize the fluorescent intensity and suppress dye leakage during tissue clearing. The spatial distribution of doxorubicin and oxidative stress were observable using the solution. Moreover, spatial distribution of liposomes in the liver was visualized. Hence, the Seebest solution provides pH-adjustable, rapid, sufficient tissue clearing, while preserving lipid ultrastructures, which is suitable for drug delivery system evaluations.

Silver Nanoparticles Production with Probiotic Bacteria

Silver nanoparticles (colloidal silver) have a bactericidal effect against a variety of bacteria, fungi and viruses. They are promising for biomedical applications due to the limited toxicity against eukaryotic cells. Important role in the silver nanoparticles production have various microorganisms including lactic acid bacteria of the genus Lactobacillus. Probiotic Lactobacillus species are good candidates for nanoparticles producing in the laboratory and in industrial scale, too. The aim of this work was to test the production of colloidal silver nanoparticles with probiotic species Lactobacillus casei. Nanoparticles production was tested in the reaction mixtures (phosphate buffer, glucose, bacterial cells) upon addition of varying concentrations of AgNO3 (1 - 4mM). Production of the silver nanoparticles was proven by screening of reaction mixtures by Transmission electron microscopy. Level of Ag+ ions utilization to nanoparticles was analysed by optical emission spectrometry. Results showed high efficiency of nanosilver production with narrow size distribution of nanoparticles (12 - 27nm).

The anthelmintic effects of the ethanol extract ofTerminalia catappaL. leaves against the ruminant gut parasite,Fischoederius cobboldi

SUMMARYPresently, no effective anthelmintic drugs have been used to treat and control paramphistomosis, a severe disease of ruminants. In this study, we have investigated thein vitroanthelmintic effect of the leaves ofTerminalia catappaL. crude extract (TcCE) and albendazole (ABZ) on adultFischoederius cobboldiafter incubating the flukes in RPMI-1640 medium containing the TcCE at various doses and times. The TcCE-treated flukes at all dosages exhibited rapid decrease of motility, and the relative motility (RM) values were decreased sharply from start to 3 h. Worms were killed after 6 and 12 h of treatment with 1000, 1500 and 2000µg mL−1as well as 500µg mL−1of TcCE, respectively. By light microscopy examination, the flukes exhibited the earliest alteration in a limited area of the tegument. At scanning electron microscopy level, the flukes’ tegument showed similar sequence of morphological alterations after treatment with ABZ and TcCE that consisted of swelling of ridges and folds, followed by blebbing and rupturing of the blebs, leading to the erosion, lesion and disruption of the tegument. Hence,in vivostudies should be performed to examine whether the TcCE may serve as a powerful anthelmintic drug for treatment of paramphistomosis.

Free-Floating Cryostat Sections for Immunoelectron Microscopy: Bridging the Gap from Light to Electron Microscopy

Since skin basement membrane protein components are labile to conventional chemical fixation and since skin is not amenable to vibratome sectioning, frozen skin sections are routinely used for light microscopic immunohistochemical study of the skin basement membrane zone. However, inherent limitations of conventional frozen sections, including compromised morphology and a requirement for glass slidemounting, usually limit study to the light microscopic level. In the present study, we introduce the use of unfixed, free-floating cryostat sections to characterize immunolocalizations of selected basement membrane protein components at both the light and electron microscopy level. The new procedure employs free-floating cryostat sections that can be processed as routine tissue specimens and can be subjected to a variety of special staining procedures including immunohistochemistry. Especially useful is the ease of progressive processing of the same tissue specimen from light microscopy to electron microscopy.

HIV-particles in spermatozoa of patients with AIDS and their transfer into the oocyte

By immunocytochemistry and in situ hybridization at the electron microscopy level, and by the PCR technique, we have shown that HIV-1 binds and enters normal sperm; that viral particles, their antigens, and nucleic acid are present in sperm from HIV-1 infected men; and that such sperm can transfer HIV-1 like particles to normal human oocytes. We also present evidence that a galactosylceramide-like compound is present on the sperm membrane and could function as an alternative receptor for HIV.