Axial Diffusivity of the Corona Radiata at 24 Hours Post-Stroke: A New Biomarker for Motor and Global Outcome

Fractional anisotropy (FA) is an effective marker of motor outcome at the chronic stage of stroke yet proves to be less efficient at early time points. This study aims to determine which diffusion metric in which location is the best marker of long-term stroke outcome after thrombolysis with diffusion tensor imaging (DTI) at 24 hours post-stroke. Twenty-eight thrombolyzed patients underwent DTI at 24 hours post-stroke onset. Ipsilesional and contralesional FA, mean (MD), axial (AD), and radial (RD) diffusivities values were calculated in different Regions-of-Interest (ROIs): (1) the white matter underlying the precentral gyrus (M1), (2) the corona radiata (CoRad), (3) the posterior limb of the internal capsule (PLIC) and (4) the cerebral peduncles (CP). NIHSS scores were acquired at admission, day 1, and day 7; modified Rankin Scores (mRS) at 3 months. Significant decreases were found in FA, MD, and AD of the ipsilesional CoRad and M1. MD and AD were also significantly lower in the PLIC. The ratio of ipsi and contralesional AD of the CoRad (CoRad-rAD) was the strongest diffusion parameter correlated with motor NIHSS scores on day 7 and with the mRS at 3 months. A Receiver-Operator Curve analysis yielded a model for the CoRad-rAD to predict good outcome based on upper limb NIHSS motor scores and mRS with high specificity and sensitivity. FA values were not correlated with clinical outcome. In conclusion, axial diffusivity of the CoRad from clinical DTI at 24 hours post-stroke is the most appropriate diffusion metric for quantifying stroke damage to predict outcome, suggesting the importance of early axonal damage.     

Temperature coupling in cricket acoustic communication

Summary Temperature effects on calling song production and recognition were investigated in the North American field cricket, Gryllus firmus. Temporal parameters of field-recorded G. firmus calling song are strongly affected by temperature. Chirp rate and syllable rate increase, by factors of 4 and 2, respectively, as linear functions of temperature over the range in which these animals sing in the field (12°–30 °C). Temperature affects syllable duration to a lesser extent, and does not influence calling song carrier frequency. Female phonotactic preference, measured on a spherical treadmill in the laboratory, also changes with temperature such that warmer females prefer songs with faster chirp and syllable rates. Best phonotaxis, measured as accuracy of orientation to the sound source, and highest walking velocity, occur in response to temperature-matched songs at 15°, 21°, and 30 °C. Experiments under semi-natural conditions in an outdoor arena revealed that females perform phonotaxis at temperatures as low as 13 °C. Taken together, the song and phonotaxis data demonstrate that this communication system is temperature coupled. A strategy is outlined by which temperature coupling may be exploited to test hypotheses about the organization of neural networks subserving song recognition.Abbreviations CP chirp period - SP syllable period - SD syllable duration     

Isolation and characterization of a large,neurite-associated glycoconjugate from neuroblastoma cells

A high molecular weight glycoconjugate has been isolated from neurite-producing neuronal tumor cells in culture and has been designated as I(0) based on its elution characteristics in gel filtration chromatography. This molecule cannot be found in a variety of nonneuronal cells. I(0) is found in the substratum-attached material or cell fraction of neurite-producing neuroblastoma cells, depending upon culture conditions. It is found in the substratum-bound fraction of B104 rat neuroblastoma cells during serum starvation and in the EGTA-detached cell fraction of B104 cells grown in chemically defined N2 medium. It occurs only in the cell fraction of the human neuroblastoma line Platt. Examination of behavioral variants of the B104 rat line further strengthens the association of I(0) with neurite production; the constitutive neurite-producing E(R)B9 variant contains I(0) while the non-neurite-producing E(R)A11 variant does not. I(0) is large, eluting in the void volume of sepharose-CL2B columns. Radioiodination of intact cells with lactoperoxidase shows I(0) to be a cell surface component. Metabolic radiolabeling studies show that it contains a high proportion of polysaccharide to protein, does not contain mannose, and is unsulfated. Alkaline borohydride reduction release two size classes of large polysaccharide chain. The alkaline reduction results, along with the mannose incorporation studies, show the presence of O-glycosidic linkages and few, if any, N-linkages. Resistance to nitrous acid deamination, insensitivity to glycosaminoglycan lyases, and the absence of sulfation, indicate that I(0) does not contain the glycosaminoglycans hyaluronic acid, chondroitin-, dermatan-, or heparin- sulfates. Affinity column chromatography reveals high binding affinity of I(0) to polyornithine and no binding to gelatin (collagen) or the glycosaminoglycans hyaluronate and heparin. These studies describe a unique high molecular weight glycoconjugate on the surface of neurite-producing neuroblastoma cell lines from two species.     

Deep-level diagnostic value of the rDNA-ITS region

The similarity of certain reported angiosperm rDNA internal transcribed spacer (ITS) region sequences to those of green algae prompted our analysis of the deep-level phylogenetic signal in the highly conserved but short 5.8S and hypervariable ITS2 sequences. We found that 5.8S sequences yield phylogenetic trees similar to but less well supported than those generated by a ca. 10-fold longer alignment from rDNA-18S sequences, as well as independent evidence. We attribute this result to our finding that, compared to 18S, the 5.8S has a higher proportion of sites subject to vary and greater among-site substitution rate homogeneity. We also determined that our phylogenetic results are not likely affected by intramolecular compensatory mutation to maintain RNA secondary structure nor by evident systematic biases in base composition. Despite historical homology, there appears to be no ITS2 primary sequence similarity shared sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that groups, however, share sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that ITS region sequences can diagnose organismal origins and phylogenetic relationships at many phylogenetic levels and provide a useful paradigm for molecular evolutionary study.      

Production of Serine Proteases by the Oyster Pathogen Perkinsus marinus (Apicomplexa) In Vitro

ABSTRACT. Analysis of the cell-free supernatants of Perkinsus marinus cultures by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining revealed the presence of as many as 17 bands ranging in molecular weight from 239 to 32 kDa. These bands were not present in un-inoculated medium. Moreover, P. marinus produces extracellular proteins that possess proteolytic activities; the cell-free supernatants of P. marinus cultures could digest a variety of proteins including gelatin, casein, fibronectin and laminin. Oyster plasma was also digested by cell-free culture supernatants. The proteolytic activity in cell-free culture supernatants was detected 24 h post-inoculation, while no proteolytic activity could be detected in cell lysates. The proteolytic activities were characterized using substrate-impregnated sodium dodecylsulfate-polyacrylamide gels and had approximate molecular weights ranging from 55 to 35 kDa. The proteolytic activity of cell-free culture supernatants was inhibited by the serine protease inhibitors phenylmethylsulphonyl fluoride, 3,4-dichloroisocoumarin and soybean trypsin inhibitor. In contrast, inhibitors (i.e. trans-epoxysuccinyll-leucylamido(4-guanidino)-butane, 1, 10-phenanthroline, captopril, ethylenediaminetetracetic acid, pepstatin A or diazoacetyl-DL-norleucine methyl ester) from the other three classes of proteases had no effect. It was concluded that the P. marinus proteases in cell-free culture supernatants are serine proteases.     

Improving protein extraction yield in reversed micellar systems through surface charge engineering

The mechanism of extraction of rat cytochrome b(5) from water into a sodium dioctylsulfosuccinate (AOT) micellar organic phase was studied using protein engineering of surface charged residues. The extraction behavior of native cytochrome b(5) and modified proteins with substitutions of the type glutamic acid --> lysine at positions 44 (E44K), 56 (E56K), and 92 (E92K), was studied as a function of pH. The results indicate that an important mechanism of extraction is an electrostatic interaction of this protein with the negatively charged surfactant. We demonstrate that it is possible to improve extraction by engineering the protein surface charge, increasing the driving force responsible for the protein transfer to the micellar phase. (c) 1994 John Wiley & Sons, Inc.     

Survey of bovine mycotic mastitis in dairy herds in the State of São Paulo,Brazil

The purpose of this study was to isolate fungi from the quarter milk of cow udders from several dairy herds and to identify the different genera and species involved in mastitis. A total of 2078 milk samples from normal, clinical and subclinical mastitis quarters from 22 dairy herds of 16 districts in the State of São Paulo, Brazil was utilized in this survey. Two hundred and fifty one (12.07%) fungi were isolated from the samples. Two hundred and eight of these (82.86%) were yeasts and 30 (11.95%) were moulds. The fungi were isolated in pure culture (24.77%) or in cultures mixed with bacteria (72.22%). The yeasts isolated were:Cryptococcus spp. (71 strains),Rhodotorula spp. (40),Candida spp. (68),Trichosporon cutaneum (21),Aureobasidium pullulans (7), andPichia ohmeri (1). Moulds classified in following genera were also isolated:Aspergillus (3),Penicillium (3),Alternaria (3),Phoma (3),Epicoccum (2), andGeotrichum (16).     

Natural lignin modulators improve bagasse saccharification of sugarcane and energy cane in field trials

The burgeoning cellulosic ethanol industry necessitates advancements in enzymatic saccharification, effective pretreatments for lignin removal, and the cultivation of crops more amenable to saccharification. Studies have demonstrated that natural inhibitors of lignin biosynthesis can enhance the saccharification of lignocellulose, even in tissues generated several months post-treatment. In this study, we applied daidzin (a competitive inhibitor of coniferaldehyde dehydrogenase), piperonylic acid (a quasi-irreversible inhibitor of cinnamate 4-hydroxylase), and methylenedioxy cinnamic acid (a competitive inhibitor of 4-coenzyme A ligase) to 60-day-old crops of two conventional Brazilian sugarcane cultivars and two energy cane clones, bred specifically for enhanced biomass production. The resultant biomasses were evaluated for lignin content and enzymatic saccharification efficiency without additional lignin-removal pretreatments. The treatments amplified the production of fermentable sugars in both the sugarcane cultivars and energy cane clones. The most successful results softened the most recalcitrant lignocellulose to the level of the least recalcitrant of the biomasses tested. Interestingly, the softest material became even more susceptible to saccharification.