Direct observation of orientation distributions of actin filaments in a solution undergoing shear banding.

Shear banding is frequently observed in complex fluids. However, the configuration of macromolecules in solutions undergoing shear banding has not yet been directly observed. In this study, by using the fact that F-actin solutions exhibit shear banding and actin filaments are visualized by fluorescent labels, we directly observed the intrinsic states of an actin solution undergoing shear banding. By combining the 3D imaging of labeled actin filaments and particle image velocimetry (PIV), we obtained orientation distributions of actin filaments in both high and low shear rate regions, whose quantitative differences are indicated. In addition, by using the orientation distributions and applying stress expression for rod-like polymers, we estimated stress tensors in both high and low shear rate regions. This evaluation indicates that different orientation distributions of filamentous macromolecules can exhibit a common shear stress.

Plant-pathogenic bacteria as biological weapons - real threats?

At present, much attention is being given to the potential of plant pathogens, including plant-pathogenic bacteria, as biological weapons/bioterror weapons. These two terms are sometimes used interchangeably and there is need for care in their application. It has been claimed that clandestine introduction of certain plant-pathogenic bacteria could cause such crop losses as to impact so significantly on a national economy and thus constitute a threat to national security. As a separate outcome, it is suggested that they could cause serious public alarm, perhaps constituting a source of terror. Legislation is now in place to regulate selected plant-pathogenic bacteria as potential weapons. However, we consider it highly doubtful that any plant-pathogenic bacterium has the requisite capabilities to justify such a classification. Even if they were so capable, the differentiation of pathogens into a special category with regulations that are even more restrictive than those currently applied in quarantine legislation of most jurisdictions offers no obvious benefit. Moreover, we believe that such regulations are disadvantageous insofar as they limit research on precisely those pathogens most in need of study. Whereas some human and animal pathogens may have potential as biological or bioterror weapons, we conclude that it is unlikely that any plant-pathogenic bacterium realistically falls into this category.

Expectation of reward modulates cognitive signals in the basal ganglia.

Action is controlled by both motivation and cognition. The basal ganglia may be the site where these kinds of information meet. Using a memory-guided saccade task with an asymmetric reward schedule, we show that visual and memory responses of caudate neurons are modulated by expectation of reward so profoundly that a neuron's preferred direction often changed with the change in the rewarded direction. The subsequent saccade to the target was earlier and faster for the rewarded direction. Our results indicate that the caudate contributes to the determination of oculomotor outputs by connecting motivational values (for example, expectation of reward) to visual information.

Actions of benzalkonium chloride as a potent depressant at the neuromuscular junction.

Benzalkonium chloride (BA), a positively charged surface active agent, applied (> 10 nM) in the superfusing solution, produced a concentration-dependent reduction in the amplitude of both evoked endplate potentials (EPPs) and spontaneous miniature EPPs of the frog. Voltage-clamped endplate currents (EPCs) and spontaneous miniature endplate currents (MEPCs) were also diminished in amplitude, in the presence of BA (50-140 nM), whereas their time-course and reversal potential were not obviously affected. No significant change due to the addition of 50 nM BA was observed in apparent properties of the ACh channel estimated from ACh-induced current fluctuations. In the relationship between the amplitude of ACh potentials and the net charge for iontophoretic pulses at a single junction, the principal pattern of action of BA (30-60 nM) appeared to be a parallel shift to the right. At concentrations greater than about 1 microM, BA slightly increased the resting input conductance of the non-synaptic muscle fibre membrane. It was suggested that this increase was attributable to a slight increase in Cl ion conductance of the non-synaptic membrane. These results indicate that BA effectively blocked neuromuscular transmission, acting as an ACh receptor antagonist at smaller concentrations and as a more potent blocker that acts through multiple sites at greater concentrations.

Serum hyaluronate in patients with acute and fulminant hepatitis.

We evaluated serum hyaluronate (HA) levels in 17 patients with acute hepatitis and 9 with fulminant hepatitis (FH). Upon admission, patients with FH showed increased levels of serum HA and these levels showed significant correlation with biochemical parameters such as human hepatocyte growth factor, hepaplastin test, and prothrombin activity. In patients with AH, the levels of serum HA decreased during convalescence. Higher serum HA levels were observed in patients with type A acute hepatitis than in patients with non-A type. In patients with FH, serum HA levels were decreased in the survivors, while they were elevated in the non-survivors. These findings suggest that serum HA levels may be a useful indicator for evaluating the prognosis of patients with acute and fulminant hepatitis. Further study is necessary to determine whether there is a causal relationship between elevated serum HA levels and the type of hepatitis virus.

Detection of New Ethylene-Producing Bacteria, Pseudomonas syringae pvs. cannabina and sesami, by PCR Amplification of Genes for the Ethylene-Forming Enzyme.

ABSTRACT Strains of Pseudomonas syringae (78 strains and 43 pathovars) and other strains (79) of plant and insect origin were examined for the presence of the ethylene-forming enzyme gene (efe) by polymerase chain reaction (PCR) assay. The sequence of the efe gene of P. syringae pv. phaseolicola PK2 was used to design two primer sets for amplification of the gene. In addition to P.syringae pv. phaseolicola (the "kudzu strain") and P.syringae pv. glycinea, which were efficient ethylene producers, several strains of P.syringae pvs. sesami and cannabina generated PCR products of the predicted size. A DNA probe of the efe gene, isolated from strain PK2, hybridized to these PCR products, indicating homology to the P.syringae pv. phaseolicola efe gene. PCR restriction fragment length polymorphism analyses suggested that these four pathovars harbor a similar efe gene. Furthermore, the probe hybridized to an indigenous plasmid of P.syringae pv. cannabina, suggesting that the efe gene could be located on a plasmid in this pathovar, but did not hybridize to plas-mids of P.syringae pv. sesami strains. P.syringae pvs. sesami and cannabina strains produced ethylene in King's medium B at levels similar to those of P.syringae pvs. phaseolicola and glycinea. Thus, two new ethylene-producing bacteria were detected by the PCR assay.

Classification, nomenclature, and plant pathogenic bacteria - a clarification.

ABSTRACT In a recent Letter to the Editor of Phytopathology, proposals were made for endorsement and for rejection of selected names of plant pathogenic Pseudomonas spp. and Xanthomonas spp. We believe that support for, and rejection of, several names was based on misconceptions concerning the Approved Lists of Bacterial Names and entails misinterpretations of several Rules of the International Code of Nomenclature of Bacteria. This letter aims to clarify those misconceptions and misinterpretations.

Effects of cesium ions on the frequency of miniature end-plate potentials at the frog neuromuscular junction.

The effects of Cs ions on the frequency of miniature end-plate potentials (MEPPs) were investigated at the frog neuromuscular junction. The frequency of MEPPs increased gradually with time, after a delay, when part of the NaCl in normal Ringer's solution was replaced isotonically with CsCl. The delay was greatly prolonged and the rate of increase in MEPP frequency slowed when a low concentration--between 6 and 40 mM--of CsCl was applied. As the external concentration of CaCl2 (0.4-6.3 mM) was increased, the delay was prolonged and the rate of increase became slower. The effect of Mg ions was qualitatively the same as that of Ca ions. In the case of reapplication, Cs ions produced a prompt increase in MEPP frequency and the rate was much faster than before. When the solution contained no added Ca and 1 mM EGTA, no appreciable change in MEPP frequency was observed when CsCl was applied. It is suggested that the first step in the gradual increase in MEPP frequency is the slow entry of Cs ions into the nerve terminal, following which transmitter release is mainly induced by the influx of external Ca ions.

Occurrence of White Top of Pea Caused by a New Strain of Pseudomonas syringae pv. pisi.

A new bacterial disease has been observed on pea in Shizuoka prefecture, Japan, since 1981. The disease occurs in early autumn when pea plants grow vigorously. The disease is characterized by chlorosis and whitening of apical shoots, including leaflets, stipules, and young pods. Usually, these white top (WT) symptoms are associated with extensive water-soaked lesions on stems and on leaflets at the basal part of the diseased plants. Thirty-four bacterial isolates from WT plants were characterized and identified together with 16 strains of Pseudomonas syringae pv. pisi from common bacterial blight of pea. The bacteria were gram-negative rods, having one to six polar flagella. The results of LOPAT tests were + - - - +, showing that they belong to P. syringe. In stab inoculation on stems, the WT isolates produced WT symptoms with water-soaked spots 14 days after inoculation. The 16 P. syringae pv. pisi strains never induced WT symptoms and, on the contrary, caused the typical bacterial blight. WT isolates were not pathogenic on any other plants tested. Phenotypic properties differentiated WT isolates and P. syringae pv. pisi strains into two groups; one consists of WT isolates and P. syringae pv. pisi group A, the other is P. syringae pv. pisi group B. Two distinct fingerprint profiles were identified by repetitive sequence based-polymerase chain reaction. WT isolates and P. syringae pv. pisi group A belonged to the same fingerprint type in rep-PCR, whereas a distinct fingerprint was shown by strains of the P. syringae pv. pisi group B. We concluded that the WT isolates should be included in P. syringae pv. pisi as a distinct strain in symptom expression.

The surgical management of parasternal recurrence of breast cancer.

Although parasternal recurrence of breast cancer can be adequately controlled by radiation therapy, at times, surgical excision is more effective. In this paper, a new technique for the radical resection of the parasternal portion of the chest wall, including dissection of the internal mammary and supraclavicular lymph nodes, is proposed. Between 1977 and 1984, eleven patients with parasternal recurrence were treated in our department. Five of these cases underwent this kind of operation and four of them are still alive without further recurrence; the remaining patient developed skin metastasis postoperatively. One patient refused radiation therapy but, in any case, radiation therapy failed to control the parasternal recurrences in the other five patients. This new operation is a rational and effective mode of treatment for parasternal recurrence.

The first report on human cases serologically diagnosed as Japanese encephalitis in Indonesia.

Although Japanese encephalitis (JE) virus was isolated from mosquitos in 1974, human JE cases have never been reported in Indonesia in spite of the prevalence of anti-JE antibodies among human and pig populations as well as abundant JE vector mosquitos. In this report, we describe serological diagnosis of JE cases in Bali. Indonesia. using IgM-capture ELISA both on serum and cerebrospinal fluid (CSF) of the patients. In the first series of our investigation (Series 1), we examined serum specimens from 12 patients with clinical diagnosis of viral encephalitis, meningitis or dengue hemorrhagic fever (DHF), and found 2 possible JE cases. In the next series (Series 2), we examined both serum and CSF from encephalitis patients and gave laboratory diagnosis of JE. One of them was suspected to have concomitant or recent infection with dengue virus, probably type 3. These results strongly indicated that JE has been prevalent in Bali, Indonesia.

[Abnormal prothrombin in acute hepatic failure: the characterization and clinical evaluation].

Abnormal prothrombin was detected by latex agglutination method in the plasma of the patients with acute hepatic failure (AHF) at significantly higher rate (82% of fulminant hepatitis and 100% of subacute hepatitis) than in acute hepatitis (33%). The concentration of abnormal prothrombin was also significantly higher in acute hepatic failure. Since the concentration of abnormal prothrombin reversely correlated with that of hepaplastin test or prothrombin time, the measurement of plasma abnormal prothrombin seemed to be useful in monitoring the severity of acute hepatic injury. Interestingly, enzyme immunoassay which is specific for des-gamma-carboxy prothrombin (PIVKA-II) could not detect abnormal prothrombin in acute hepatic failure. Furthermore, in crossed immune-electrophoresis, the abnormal prothrombin in AHF and that in disseminated intravascular coagulation syndrome showed similar mobility differing from PIVKA-II. These results suggest that abnormal prothrombin can be a useful marker for AHF. Further characterization of the abnormal prothrombin may shed light on the mechanisms of severe coagulopathy in AHF.

[High prevalence of TT virus(TTV) in patients with non A to non G fulminant hepatitis: differences of clinical features and prognosis between TTV positive and negative patients].

We detected TTV-DNA in sera from 36 patients with fulminant hepatitis(FH) and evaluated differences in clinical features and prognosis between TTV-DNA positive and negative patients with nonA-nonG FH. TTV-DNA in sera was measured by nested PCR. Twenty of 36 patients with FH were diagnosed nonA-nonG FH. The TTV-DNA in sera was detected in 14 patients(38.9%) with FH, 9(64%) showed nonA-nonG FH and 3 were HBV FH and 2 were drug-induced FH. Although we compared clinical features(gender, age, distribution history of blood transfusion, initial symptoms of hepatitis, and liver function tests) and prognosis between TTV positive and negative patients with nonA-nonG FH, there were no significant differences between the two groups. These data suggest that although TTV may be a infectious agent related to nonA-nonG FH, further study is needed to clarify the role of TTV in the pathogenesis of FH.

Targeted destruction of fungal structures of Erysiphe trifoliorum on flat leaf surfaces of Marchantia polymorpha.

In this study, we observed the germination behaviour of airborne conidia from powdery mildews that settle on thalloid surfaces. We inoculated thalli (flat, sheet-like leaf tissues) and gemmae (small, flat, sheet-like leaf tissues that propagate asexually via bud-like structures) of the common liverwort (Marchantia polymorpha) with conidia from tomato powdery mildew (Oidium neolycopersici; KTP-02) and red clover powdery mildew (Erysiphe trifoliorum; KRCP-4N) and examined their germination and subsequent appressorium formation under a high-fidelity digital microscope. Conidial bodies and germ tubes of the inoculated KRCP-4N conidia were destroyed on both the thalli and gemmae. The destruction of these fungal structures was observed only for KRCP-4N conidia inoculated onto M. polymorpha on both leaf surfaces. No differences in destruction of the KRCP-4N fungal structures between thalli and gemmae were observed. At 4 h post-inoculation, destruction of the germ tube tip was observed when it reached the gemmae leaf surface. At 6 h post-inoculation, the conidial bodies and germ tubes were destroyed. In contrast, KTP-02 conidia were not destroyed and formed normal, well-lobed appressoria on the surface of M. polymorpha gemmae.

Role of the basal ganglia in the control of purposive saccadic eye movements.

In addition to their well-known role in skeletal movements, the basal ganglia control saccadic eye movements (saccades) by means of their connection to the superior colliculus (SC). The SC receives convergent inputs from cerebral cortical areas and the basal ganglia. To make a saccade to an object purposefully, appropriate signals must be selected out of the cortical inputs, in which the basal ganglia play a crucial role. This is done by the sustained inhibitory input from the substantia nigra pars reticulata (SNr) to the SC. This inhibition can be removed by another inhibition from the caudate nucleus (CD) to the SNr, which results in a disinhibition of the SC. The basal ganglia have another mechanism, involving the external segment of the globus pallidus and the subthalamic nucleus, with which the SNr-SC inhibition can further be enhanced. The sensorimotor signals carried by the basal ganglia neurons are strongly modulated depending on the behavioral context, which reflects working memory, expectation, and attention. Expectation of reward is a critical determinant in that the saccade that has been rewarded is facilitated subsequently. The interaction between cortical and dopaminergic inputs to CD neurons may underlie the behavioral adaptation toward purposeful saccades.