Pseudomonas aeruginosa. II. Experimental acellular vaccine of an endotoxin and anatoxin type

The results are given of quality evaluation of endotoxin and exotoxin antigens isolated from P. aeruginosa strains. The isolates were tested by both in vitro and in vivo methods. The results of an active protection test on white mice formed the basis for the construction of an experimental Pseudomonas vaccine that protects the immunized animals against infection even by heterologous strains of P. aeruginosa.     

Interaction of visceral and somatic afferentation at the level of postsynaptic spinal cord elements.

The interaction of visceral and somatic afferentation at the level of postsynaptic spinal cord elements was studied in cats. The effect of conditioning stimuli on the propriospinal (PS) and suprasegmental (SS) component of the tested unit responses was compared. Afferentation from the splanchnic nerve completely inhibited the SS component of somatomotor motoneuronal responses; the PS component was only partly inhibited. Inhibition persisted even after the conditioning stimulus-induced changes in the membrane potential of the motoneurones had disappeared. The activity of the interneurones responsing synchronously with the SS component of the efferent discharges was also completely inhibited in the same intervals. The inhibitory effect of splanchnic afferentation on the PS component of interneuronal discharges evoked by the stimulation of somatic afferents was significantly less effective. The results of interaction for test responses from the cutaneous and muscular nerves was the same. When splanchnic responses were tested during conditioning from somatosensory areas, inhibitory control was found to be reciprocal. The authors discuss the question of the structures and mechanisms participating in functional relations between the autonomic and somatic nervous system in the spinal cord.     

Long systems of the dorsolateral fascicle: influence of afferentation from the splanchnic region.

The influence of afferentation from the splanchnic region on the activity of long systems in the dorsolateral fascicle (DLF) was studied in chloralose-anaesthetized cats. Ascending axons (the dorsal spinocerebellar tract, DSCT and the spinocervical tract, SCT) did not respond to splanchnic stimuli. Conditioning from the splanchnic region modified their activity; the effect (mainly inhibitory) was strongest in the case of exteroceptive channels. The reaction of long propriospinal neurones depended on whether they belonged to ascending or descending pathways. No responses to splanchic stimuli were observed in the axons of ascending (proprioceptive, exteroceptive) units and conditioning from the splanchnic region only modified their activity. In decending axons, synaptic discharges with a long latent period (over 20 msec) were generated. The interaction of inputs from the visceral and somatosensory regions resulted in reciprocal inhibition of the tested activity. In axons descending from suprasegmental areas, splanchnic afferentation generated synaptic discharges with a time course comparable to spino-bulbo-spinal activity. Interaction with the responses from somatic nerves resulted inhibition of the tested activity. The results confirmed that the splanchnic region participates in modifying and evoking activity in the long DLF systems.     

Cadmium immobilization in the rhizosphere of arbuscular mycorrhizal plants by the fungal extraradical mycelium

The aim of the study was to assess how the extraradical mycelium (ERM) of arbuscular mycorrhizal (AM) fungi contributes to Cd immobilization in the rhizosphere. Substrates prepared by cultivation of AM and non-mycorrhizal tobacco (Nicotiana tabacum L.) in quartz sand in two experiments were amended with Cd in a range of concentrations and Cd immobilization was assessed as Cd toxicity using root growth tests. Split-root plants, inoculated at one part of the root system, and hyphal compartments colonized by ERM only were used to separate the effects of ERM from plant-mediated effects of mycorrhiza and from the effects of roots. AM decreased Cd toxicity in the substrates obtained by 12 weeks of cultivation (Experiment 1), while the effect was less clear after 8 weeks (Experiment 2). No indication was found for an involvement of plant-mediated effects; in contrast, the effect of ERM could be clearly demonstrated. Lower Cd toxicity in the substrates colonized by ERM was related to ERM-induced alkalinization, but not directly to ERM density. It is concluded that the ERM of AM fungi may enhance Cd immobilisation in soil not only due to its high Cd sorption capacity but also by its activity.     

Limbic irritability and chaotic neural response during conflicting stroop task in the patients with unipolar depression

According to recent findings activation of anterior cingulate cortex (ACC) is related to detecting cognitive conflict. This conflict related activation elicits autonomic responses which can be assessed by psychophysiological measures such as heart rate variability calculated as beat to beat R-R intervals (RRI). Recent findings in neuroscience also suggest that cognitive conflict is related to specific nonlinear chaotic changes of the signal generated by neural systems. The present study used Stroop word-color test as an experimental approach to psychophysiological study of cognitive conflict in connection with RRI measurement, psychometric measurement of limbic irritability (LSCL-33), depression (BDI-II) and calculation of largest Lyapunov exponents in nonlinear data analysis of RRI time series. Significant correlation 0.61 between largest Lyapunov exponents and LSCL-33 found in this study indicate that a defect of neural inhibition during conflicting Stroop task is closely related to limbic irritability. Because limbic irritability is probably closely related to epileptiform abnormalities in the temporolimbic structures, this result might represent useful instrument for indication of anticonvulsant treatment in depressive patients who are resistant to antidepressant medication.     

Advanced resources for plant genomics: a BAC library specific for the short arm of wheat chromosome 1B

Common wheat (Triticum aestivum L., 2n = 6x = 42) is a polyploid species possessing one of the largest genomes among the cultivated crops (1C is approximately 17 000 Mb). The presence of three homoeologous genomes (A, B and D), and the prevalence of repetitive DNA make sequencing the wheat genome a daunting task. We have developed a novel 'chromosome arm-based' strategy for wheat genome sequencing to simplify this task; this relies on sub-genomic libraries of large DNA inserts. In this paper, we used a di-telosomic line of wheat to isolate six million copies of the short arm of chromosome 1B (1BS) by flow sorting. Chromosomal DNA was partially digested with HindIII and used to construct an arm-specific BAC library. The library consists of 65 280 clones with an average insert size of 82 kb. Almost half of the library (45%) has inserts larger than 100 kb, while 18% of the inserts range in size between 75 and 100 kb, and 37% are shorter than 75 kb. We estimated the chromosome arm coverage to be 14.5-fold, giving a 99.9% probability of identifying a clone corresponding to any sequence on the short arm of 1B. Each chromosome arm in wheat can be flow sorted from an appropriate cytogenetic stock, and we envisage that the availability of chromosome arm-specific BAC resources in wheat will greatly facilitate the development of ready-to-sequence physical maps and map-based gene cloning.     

Comparison of the conventional culture,the manual fluorescent MGIT system and the automated fluorescent MGIT 960 culture system for the detection of <Emphasis Type="Italic">Mycobacterium avium</Emphasis> ssp. <Emphasis Type="Italic">avium</Emphasis> in tissues of naturally infected hens

Different methods for the detection of Mycobacterium avium ssp. avium (MAA) in naturally infected hens were compared. They included the conventional culture method (solid Herrold’s and Stonebrink media and liquid Sula medium) and newly developed liquid culture systems, the manual mycobacteria growth indicator tube (M-MGIT) and the fully automated BACTEC MGIT 960 system (A-MGIT). 152 tissues originating from 15 naturally infected hens have been processed. The overall detection rates (percentage of positive cultures from the number of positive cultures determined by all the methods together) were 60, 70 and 76 % for the conventional media, M-MGIT and A-MGIT systems, respectively, the mean time of mycobacteria detection being 32.6, 17.6 and 14.6 d, respectively. The lowest contamination rate (2.0 %) was found in A-MGIT compared with M-MGIT (4.6 %) and conventional media (10.4 %).