Fluorescence

Conventional methods to detect and assess the viability of plant pathogenic bacteria are usually based on plating assays or serological techniques. Plating assays provide information about the number of viable cells, expressed as colony-forming units, but are time-consuming and laborious. Serological methods, such as the enzyme-linked immunosorbent assay (ELISA) and immunofluorescence microscopy (IF), can be performed in a shorter timespan than most plating assays, but they do not discriminate between live and dead cells. Flow cytometry (FCM) in combination with fluorescent probe technology is a rapid, sensitive, and quantitative technique to detect microorganisms and assess their viability. Quantitative information on the presence and viability of plant pathogenic microorganisms is valuable for risk assessment regarding disease transmission and disease development. FCM has been applied successfully in the fields of food microbiology, veterinary science, and medical research to dete...

Trabajo presentado en el Workshop on UAV-based Remote Sensing Methods for Monitoring Vegetation, celebrado en Colonia (Alemania) el 9 y 10 de septiembre de 2013. Mas informacion en http://www.tr32db.uni-koeln.de/workshops/proceedings.php?wsID=3.

Sixteen novel 2-aminobenzothiazole based dichromophoric cationic azo dyes were synthesized and their photophysical properties studied. The colors of the synthesized azo dyes were violet to blue with high molecular extinction coefficient ranged between 2.6-4.7 10 4 (M-1 .cm-1). All of the dyes showed unique fluorescence emission at a broad range of 409-494 nm. The absorption and emission spectral changes of selected dyes were also analyzed in solvents with different polarity. Furthermore, the antibacterial activities of the dyes were evaluated against gram positive and negative bacteria including S. aureus, S. epidermidis, E. coli, and P. aeruginosa and different concentrations of dyes showed an anti-gram positive bacterial activity.

: The quantitative description of cell structures in light microscope images is an important task in biological research. The inclusion of digital image processing techniques and fluorescent markers into light microscope imaging has recently made this task feasible. In this paper, we present a method for detection of filamentary structures in cell images that have been highlighted with fluorescent markers. The method has three stages. First, pixels belonging to fiber contours are extracted from the image. Then these pixels are grouped together based on proximity by a minimal spanning tree. Finally, the fiber contours are determined as sub-trees of the minimal spanning tree. Once the pixels belonging to individual fibers contours have been determined, quantitative statistics describing the fibers in the cell can be calculated.

Cancer 3-D spheroids are widely used to test drugs and radiotherapy treatments. These 3-D cell clusters range from tens to hundreds of micrometers in size, with shapes that typically differ from a perfect sphere. Change in spheroid volume is one of the most important parameters for evaluating treatment efficacy, and using light sheet fluorescence microscopes (LSFM), optical sections of samples in that size range can be obtained. However, there remains a lack of validated methods for quantifying the volumes of 3-D multicellular aggregates. Here, we present Reconstruction and Visualization from Multiple Sections (ReViMS), an open-source, user-friendly software for automatically segmenting z-stacks of fluorescence images and estimating the volumes of 3-D multicellular spheroids. To assess the precision and accuracy of the volume estimates obtained with ReViMS, we used several cancer spheroids imaged with LSFM. Both the precision and accuracy were >95%, demonstrating the effectivenes...

Rhus succedanea is generally traded, distributed and sold in the markets in its crude and raw form. This may have been mixed with adulterants, mismanaged by malpractices and substituted with other closely related drugs having different effect. This study is therefore carried out to authenticate the plant through pharmacogonostic evaluations. The organoleptic studies were carried through sensory organs i.e size, shape, texrure, odour, etc. Histological studies were conducted by preparing hand slides, mounting the specimen in potato tuber; fluorescence characters were determined through UV and phytochemical screening was investigated using various standard and common methods from relevant literature. Morphologically, the Rhus is a perennial small sized deciduous tree, 5-9 m tall with opposite imparipinnately compound leaves and small grayish yellow flowers born on paniculate inflorescence; locally, called as Rakhkal in Pashto and Kakarsingi in Urdu. The organoleptic evaluation showed ...

A complete set of platinum(II) solketal substituted phthalocyanines has been synthesized and characterized. To evaluate their potential as Type II photosensitizers for photodynamic therapy, comparative studies of their photophysical and photochemical properties with analogous zinc(II) series have been achieved: electronic absorption, fluorescence quantum yields, lifetimes, and fluorescence quenching by benzoquinone, as well as singlet oxygen generation and photodegradation. It appears that platinum(II) phthalocyanines are worth being used as Type II photosensitizers, as they exhibit good singlet oxygen generation and appropriate photodegradation.

Fusarium circinatum is the causal agent of pitch canker disease affecting Pinus spp. and Pseudotsuga menziesii worldwide. Under strict quarantine measures, alternative approaches for disease control are necessary. Phosphite (Phi) salts are known for their fungicidal activity and as plant resistance elicitors; however, its potential is yet to be acknowledged in the Pinus-F. circinatum model. The main aim of this study was to assess whether the application of a Phi-based commercial formulation would delay the progression of the pitch canker on Pinus radiata plants, and on the in vitro fungal growth. In vitro assays were performed using different Phi concentrations (1% and 4%) and a non-treated control (0%), and repeated in vivo using inoculated and non-inoculated plants. Plant physiological parameters and hormonal content were evaluated. Phi was effective at inhibiting in vitro mycelial growth in a dose dependent manner. Regardless of fungal inoculation, Phi application induced positi...

Synthesis and photophysical studies of (O-methyl)-ß-tyrosine (ß-tyrosine; an analogue of tyrosine, in which the amino group is moved from the a-to the ß-carbon, closer to the phenol ring) and its derivatives with a blocked amino and/or carboxyl group were performed to ...

A high-performance liquid chromatography (HPLC) procedure for the separation of choline lysophospholids including 1-acyl-lysophosphatidylcholines and 1-O-alkyl-lysophosphatidyl-cholines, like the lysoform of the platelet activating factor (2-lysoPAF), is described. The ...