Characterization of peptidyl-nucleoside antifungal antibiotics from fermentation broth

Summary Characterization of sinefungin related antifungal antibiotics from fermentation broth was accomplished by coupling photodiode array (PDA) detection to high performance liquid chromatography (HPLC). From the combined HPLC-PDA evaluation of broth filtrate, we detected five sinefungin related components. Fast atom bombardment (FAB) mass spectroscopic evaluations, mass-analysed ion kinetic energy spectra (MIKES) and collision activated (CA) MIKES of these components confirmed their respective identities. Our findings from the combination of HPLC photodiode array acquisition and FAB-mass spectrometry suggest we have detected the presence of a previously unreported sinefungin analogue.     

Arachidonic acid epoxygenase: detection of epoxyeicosatrienoic acids in human urine

Epoxyeicosatrienoic acids, metabolites of the cytochrome P-450-mediated epoxygenase reaction, were detected in human urine by gas chromatographic-mass spectroscopic techniques after conversion to their hydrogenated and non-hydrogenated methyl and pentafluorobenzyl esters. Initial analysis of the regioisomeric composition utilizing the corresponding hydrogenated pentafluorobenzyl esters revealed the presence of the 8,9- and 14,15-isomers.     

The gene encoding translation initiation factor 3 is highly conserved in gram-negative bacteria

A 1.1-kb Hp alpha I fragment of the Escherichia coli chromosome containing the gene for translation initiation factor 3 was employed as a probe in heterologous hybridization to chromosomal DNA from a variety of other procaryotes. Positive hybridization was observed to DNA derived from all gram-negative bacteria tested. In contrast, no hybridization to DNA from gram-positive bacteria was detected. In addition, homologous sequences were found in Euglena gracilis chloroplast DNA, while this was not the case with Saccharomyces cerevisiae mitochondrial DNA. These results are discussed in light of existing data on the components and mechanism of translation initiation in the various organisms and organelles employed in this study.     

Arachidonate epoxygenase: identification of epoxyeicosatrienoic acids in rabbit kidney

Epoxyeicosatrienoic acids were isolated and purified from female rabbit kidneys. They were identified as a group, prior to resolution, by packed column gas-liquid chromatography-mass spectroscopic techniques as their methyl esters as well as their trimethylsilyl bromohydrin methyl esters. Initial capillary gas-liquid chromatography-mass spectral analysis of the corresponding hydrogenated pentafluorobenzyl esters revealed the presence of the 8,9- and 14,15-epoxyeicosatrienoate regioisomers. These results, in conjunction with the documented in vitro biological activities of the arachidonate epoxygenase metabolites, suggest a role for them in renal function.     

High resolution,label‐free photoacoustic imaging of live chicken embryo developing in bioengineered eggshell

Chicken embryos have been proven to be an attractive vertebrate model for biomedical research. They have helped in making significant contributions for advancements in various fields like developmental biology, cancer research and cardiovascular studies. However, a non‐invasive, label‐free method of imaging live chicken embryo at high resolution still needs to be developed and optimized. In this work, we have shown the potential of photoacoustic tomography (PAT) for imaging live chicken embryos cultured in bioengineered eggshells. Laser pulses at wavelengths of 532 and 740 nm were used for attaining cross‐sectional images of chicken embryos at different developmental stages. Cross‐sections along different depths were imaged to gain knowledge of the relative depth of different vessels and organs. Due to high optical absorption of vasculature and embryonic eye, images with good optical contrast could be acquired using this method. We have thus reported a label‐free method of performing cross‐sectional imaging of chicken embryos at high resolution demonstrating the capacity of PAT as a promising tool for avian embryo imaging.     

In vivo detection of venous sinus distension due to intracranial hypotension in small animal using pulsed‐laser‐diode photoacoustic tomography

Intracranial hypotension (IH) is a pathophysiological condition of reduced intracranial pressure caused by low cerebrospinal fluid (CSF) volume due to dural injuries from lumbar puncture, surgery, or trauma. Understanding the prognosis of IH in small animal models is important to gain insights on the complications associated with it such as orthostatic headache, cerebral venous thrombosis, coma, and so forth. Photoacoustic tomography (PAT) offers a novel and cost‐effective way to perceive and detect IH in small animal models. In this study, a pulsed laser diode (PLD)‐based PAT imaging system was used to examine the changes in the venous sinuses of the rat brain due to IH, induced through CSF extraction. After the CSF extraction, an increase in the sagittal sinus area by ~30% and width by 40% ± 5% was observed. These results provide supportive evidence that the PLD‐PAT can be employed for detecting changes in sagittal sinus due to IH in rat model.     

DNA content, chromosome composition, and isozyme patterns inPlantago L.

Retrospective as well as recent records on DNA content, chromosome composition, and isozyme variation were analyzed critically to trace the evolution of species of the genusPlantago. Both in vivo as well as in vitro data were taken into consideration. The species withX 6 were considered to be ancestral, whereas those withX= 5 were considered to be more advanced. The cultivated species withX= 4 was thought to be a derivative ofX = 5. The data on isozyme variation supported the findings derived from DNA and chromosome composition.