The effect of the length of a malarial epitope on its antigenicity and immunogenicity in an epitope presentation system using the Pseudomonas aeruginosa outer membrane protein OprF as the carrier

The phenotypic characteristics of three Serpulina pilosicoli strains isolated from humans with diarrhoea (WesB, Kar, Hrm7) and two porcine S. pilosicoli strains isolated from pigs with intestinal spirochaetosis (1648, 3295), were compared with the type strain of the species P43/6/78T (T = type strain) and other intestinal spirochaetes within the genus Serpulina. All S. pilosicoli strains had a characteristic ultrastructural appearance, displayed similar growth rates, hydrolysed hippurate, lacked beta-glucosidase activity, utilised D-ribose as a growth substrate, and had similar sensitivities to rifampicin and spiramycin. The only consistent phenotypic characteristic that differentiated human strains from porcine strains of S. pilosicoli was that the human strains all utilised the pentose sugar D-xylose. These distinguishing phenotypic traits appear useful for identifying S. pilosicoli.     

Micro- and nanofabrication processes for hybrid synthetic and biological system fabrication

The application of micro- and nanofabrication processes to the development of hybrid synthetic and biological systems may enable the production of new devices such as controllable transporters, gears, levers, micropumps, or microgenerators powered by biological molecular motors. However, engineering these hybrid devices requires fabrication processes that are compatible with biological materials such as kinesin motor proteins and microtubules. In this paper, the effects of micro- and nanofabrication processing chemicals and resists on the functionality of casein, kinesin, and microtubule proteins are systematically examined to address the important missing link of the biocompatibility of micro- and nanofabrication processes needed to realize hybrid system fabrication. It is found that both casein, which is used to prevent motor denaturation on surfaces, and kinesin motors are surprisingly tolerant of most of the processing chemicals examined. Microtubules, however, are much more sensitive. Exposure to the processing chemicals leads to depolymerization, which is partially attributed to the pH of the solutions examined. When the chemicals were diluted in aqueous buffers, a subset of them no longer depolymerized microtubules and in their diluted forms still worked as resist removers. This approach broadens the application of micro- and nanofabrication processes to hybrid synthetic and biological system fabrication.     

Primary afferent depolarizations of sensory origin within contact-sensitive mechanoreceptive afferents of a crayfish leg

Recordings from the central branches of single identified dactyl sensory afferent (DSA) neurons in a crayfish in vitro preparation were performed to study modifications of the sensory message occurring before the first central synapse. These afferents comprised hairs and force-sensitive mechanoreceptors with phasic and phasotonic response characteristics in the terminal segment (dactyl) of the crayfish leg. More than one afferent spike size was often observed in intracellular recordings from these afferents, thus indicating the presence of electrical coupling between the central processes of DSA fibers. Additionally, in identified DSA fibers with large spike sizes, primary afferent depolarizations (PADs) of up to 15 mV were observed, which sometimes triggered antidromic spikes in the afferent. Nevertheless, PADs were clearly inhibitory, because they shunted the afferent spikes. They exhibited the following properties. First, each PAD was preceded by an afferent spike from a neighboring hair, indicating that the PADs had a sensory rather than central origin. Second, PADs could follow high frequencies of afferent discharges without failure, a property suggestive of monosynaptic connections, but because PAD latencies varied by +/-0.5 ms it is more likely that they were mediated by a disynaptic pathway. Third, although PADs were evoked in an extremely reliable manner, their amplitude varied in a quantal manner. Most unitary PADs were the result of the release of < 12 quanta, the mean quantal content lying between 4 and 5; quantal size was large, approximately 1 mV. Fourth, PADs showed facilitation in some fibers, whereas in others they became much smaller when occurring at brief intervals. We suggest that PADs may be an efficient and parsimonious way to limit sensory inflow in space and time, allowing the crayfish to identify precisely both weak and strong mechanical stimuli.     

Passive sensitization of human airways induces myogenic contractile responses in vitro

We assessed effects of passive sensitization on human bronchial smooth muscle (BSM) response to mechanical stretching in vitro. Bronchial rings were sham (control) or passively sensitized overnight by using sera from donors demonstrating sensitivity to Dermatophagoides farinae and having immunoglobulin E (IgE) concentrations of 2,600 +/- 200 U/ml. Tissues were fixed isometrically to force transducers to measure responses to electrical field stimulation (EFS) and quick stretch (QS). The myogenic response to QS was normalized to the maximal response to EFS (%EFS). The myogenic response of sensitized BSM was 47.9 +/- 10.9 %EFS to a QS of approximately 6.5% optimal length (Lo); sham-sensitized tissues had a myogenic response of 13.5 +/- 6.4 %EFS (P = 0.012 vs. passively sensitized). A QS of approximately 13% Lo in sensitized BSM caused a response of 82.8 +/- 20.9 %EFS; sham-sensitized tissues developed a response of 38.2 +/- 17.3 %EFS (P = 0.004). BSM incubated with serum from nonallergic donors did not demonstrate increased QS response (4.6 +/- 1.4 %EFS, P = not significant vs. tissue exposed to atopic sera). However, tissues incubated in sera from nonatopic donors supplemented with hapten-specific chimeric IgE (JW8) demonstrated augmented myogenic response to QS of approximately 6.5% Lo (21.9 +/- 6.2 %EFS, P = 0. 027 vs. nonatopic sera alone). We demonstrate that passive sensitization of human BSM preparations causes induction and augmentation of myogenic contractions to QS; this hyperresponsiveness corresponds to the IgE concentration in sensitizing sera.     

Growth factor receptor expression during in vitro differentiation of partially purified populations containing murine stem cells

The Word Accentuation Test assesses the accentuation of 30 infrequent Spanish words written without the accentuation mark and is an easy-to-use tool for estimating premorbid intelligence of Spanish-speaking people. Its intraobserver (0.97) and interobserver (0.93) reliabilities and its correlation with the Wechsler Adult Intelligence Scale (.837) and Raven's Progressive Matrices (.655) are high, offering a good prediction of general intelligence. It is resistant to mental deterioration; 20 demented and 40 controls matched by sex, age, and education obtained similar scores. The discrepancies between current and predicted scores in Raven's scale can diagnose mild-moderate dementia with 0.79 accuracy (sensitivity, 0.78; specificity, 0.82).     

Antimutagenic activity of casein against MNNG in the E. coli DNA repair host-mediated assay

The effect of caseinate and soy protein in the diet on the mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was assessed in-vivo and ex-vivo in the DNA-repair host-mediated assay and liquid suspension assay, respectively. Of the two proteins only casein showed a strong antimutagenic activity over the whole digestive tract, except in the stomach. It is suggested that the molecular structure of a protein determines its protective effect against mutagens: casein lacks secondary and tertiary structure so that amino acids are more readily available for interaction with the mutagen than with the amino acids in soy protein which is a globular protein.