The mechanism of object fixation and its relation to spontaneous pattern preferences in Drosophila melanogaster

The orientation behavior of walking flies, Drosophila melanogaster, towards a single 6° wide black vertical stripe (elementary stripe) can be explained by use of the turning tendency function H(). This function is characterized by maximal values at an angular distance of =25° from the stable zero position (=orienting direction), a sharp decline from this maximum to =60°, and a very slow approach to the unstable zero position (Horn and Wehner, 1975). The shape of this function is influenced by both translatory and rotatory components of movement. If the translatory component is minimized by measuring the turning function W() (see 2.3) at a distance of 10 mm (C1) from the center of the arena, a change in the strength of this decline is caused. But with increasing translatory component, i.e. at a greater distance from the center of the arena, W() approximates the heuristical function H() (Fig. 12). The turning functions W() are pattern-specific; the angular positions of the maximum responses shift to greater angles with increasing width of the patterns (Fig. 2). In the twopattern configuration with double or single stripes, there is always a coincidence between the stable zero positions of W (), the mean of the frequency distributions P() of the flies' positions and n _g() of the straight courses, and the stable zero positions of H () obtained from an additive superposition of two or more angular shifted turning tendency functions H() (Fig. 5, 7). Therefore, the mean positions of the flies in a multi-stripe experiment composed of elementary stripes can be predicted from the addition of many angular shifted turning tendency functions H(). Between H() and the frequency distribution P() of the flies' positions , the following formula holds: P() =C·H()d (Fig. 13). With this equation, the spontaneous preference of the broader of two double stripes can be explained presuming lateral interactions between the components of the patterns (Fig. 8, 10). The strength x _i ^* of this lateral interaction depends on the width of the double stripes. The greater , the smaller is x _i ^* . x _i ^* is a pattern-specific value (Table 1, 2).Supported by the Deutsche Forschungsgemeinschaft, Ho 664/2     

The effects of frontal EMG biofeedback and progressive relaxation upon hyperactivity and its behavioral concomitants

Hyperactive children(N=15) and nonhyperactive children(N=15) were compared. Hyperactive children were found to possess significantly higher(p < .002) muscular tension levels and, in addition, presented more behavioral problems and had lower test scores. Both electromyographic(EMG) biofeedback and progressive relaxation exercises were successful in the significant reduction of muscular tension, hyperactivity, distractability, irritability, impulsivity, explosiveness, aggressivity, and emotionality in hyperactive children. The greatest improvement was seen in the area of emotionality—aggression(irritability, explosiveness, impulsivity, low frustration tolerance, aggression). No differences were seen in the EMG improvement of drug and nondrug hyperactive children; both made progress under these self-control techniques. However, nondrug children made greater improvements in the behavioral area. Both EMG biofeedback and progressive relaxation resulted in improvements on the test scores of hyperactive subjects(Bender-Gestalt, Visual Sequential Memory, Digit Span, Coding). The therapy would appear to be improved by the inclusion of mental relaxation, concentration, meditation, and mind-blanking exercises for mental control.     

Syndecan-4 as a molecule involved in defense mechanisms

Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Syndecan-4-deficient [(Synd4(–/–)] mice were produced to clarify the in vivo role of syndecan-4. Synd4(–/–) mice were more susceptible to -carrageenan-induced nephropathy, and the placental labyrinth from the deficient embryos exhibited more thrombi than wild-type ones. Importantly, Synd4(–/–) mice were more susceptible to endotoxin shock. Further analysis revealed that the mechanism to suppress excessive production of interleukin-1 (1L-1) by transforming growth factor- (TGF-) was impaired in the deficient mice. TGF-, one of the cytokines involved in the suppression mechanism, bound to heparan sulfate chain of syndecan-4, which was induced in macrophages and the microvasculature after administration of lipopolysaccharide. Therefore, augmentation of TGF- function by induced syndecan-4 was suggested as a mechanism of the suppressive action of syndecan-4 against endotoxin shock. Published in 2003.     

Mannosyl-β(1-4)-N-acetylglucosaminyl-β(1-N)-urea,a compound isolated from the urine of patients with β-mannosidosis

A previously unknown substance, mannosyl-(1–4)-N-acetylglucosaminyl-(1-N)-urea, has been isolated from the urine of patients with -mannosidosis in addition to the main metabolite mannosyl-(1–4)-N-acetylglucosamine. Structural investigation was carried out by fast atom bombardment mass spectrometry and high-resolution¹H-nuclear magnetic resonance spectroscopy at 500 MHz. It was postulated that the occurrence of this carbohydrate-urea conjugate in urine results mainly from urine handling.     

Long Range Force between Pre-Replication Complexes (Pre-RC) in DNA Controls Replication and Cell Cycle Progression

A nonstationary interaction, that controls DNA replication and the cell cycle, is derived from a manybody physics model in a chemically open T cell. The model predicts a long range force F()=-(/2) (1-)(2-) between the pre-replication complexes (pre-RCs) bound by DNA, =/N being the relative displacement of preRCs, the number of pre-RCs, N the threshold for initiation, and the compressibility modulus in thelattice of pre-RCs which behaves like an elastically braced string. Initiation of DNA replication is induced by a switch of sign of F(), from attraction (-)and assembly in the G ₁ phase (0 < < N), to repulsion (+) and partialdisassembly in the S phase (N < < 2N), with release of licensing factors from the pre-RCs, thus explaining prevention of re-replication. Replication is terminated by a switch of sign of F at = 2N, when all primed replicons are duplicated once, and F(0)=0 corresponds to a resting cell in absence of driving force at = 0. The switch of sign of force at = N also explains the dynamic instability in growing microtubules (MTs), as well as switch in the interleukin-2 (IL2) interaction with its receptor in late G ₁, at the restriction point. Shape, slope and scale of the response curves derived agree well with experimental data from dividing T cells and polymerizing MTs, the variable length of which is due to anonlinear dependence of the growth amplitude on the initial concentrations of tubulin dimers and guanosine-tri-phosphate (GTP).     

Chemoenzymatic galactosialylation with integrated cofactor regeneration

As a precursor for the chemical synthesis of sialylated oligosaccharides, the trisaccharide glycoside Neu5Ac (2-8)Gal(1-4)GlcNAc(1-O)-pent-4-ene was synthesized starting from GlcNAc(1-O)-pent-4-ene, UDP-glucose andN-acetylneuraminic acid in a one pot reaction employing galactosyltransferase and (2-6)sialyl-transferase in a complete cofactor regeneration system.Abbreviations Neu5Ac N-acetylneuraminic acid - CMP-Neu5Ac cytidine 5-monophosphosialate - CMP cytidine 5-monophosphate - CDP cytidine 5-diphosphate - CTP cytidine 5-triphosphate - Gal galactose - GlcNAc N-acetylglucosamine - UDP uridine 5-diphosphate - UDP-Glc uridine-5-diphosphoglucose - UDP-Gal uridine-5-diphosphogalactose - PEP phosphoenolpyruvate     

Persistence of maternal isoenzyme patterns of the lactate dehydrogenase and phosphoglucomutase system during early development of hybrid trout

Developmental changes in the isoenzyme patterns of LDH and PGM during early embryogenesis (until hatching) in two trout species (Salmo trutta and Salmo irideus) as well as in their reciprocal interspecific hybrids are reported, completing a previous study which had commenced from hatching onward (Hitzeroth et al., 1968). Isoenzymes of both systems occur in unfertilized eggs and in embryos from fertilization onward. Until about the Augenpunkt stage, the isoenzyme patterns remain unchanged and are identical to the patterns of unfertilized eggs; the reciprocal hybrids correspond to the respective maternal species. Additional isoenzymes appearing for the first time at about the Augenpunkt stage in the interspecific hybrids show the same electrophoretic mobility as those in the animals of the respective maternal species at this developmental stage. It is discussed whether the appearance of additional isoenzymes characterizes the activation of maternally derived alleles of the embryonic genome, or whether maternally derived cytoplasmic factors are responsible for the occurrence of these additional bands.Supported by the Deutsche Forschungsgemeinschaft.     

Streptomycetes excreting dd-carboxypeptidases

Summary Excretion of exocellular dd-carboxypeptidases was tested using 128 strains of streptomycetes. Exocellular enzyme activity was shown in 13% of the trains investigated. Streptomyces strains showed low activity of excretion of dd-carboxypeptidases: 2.7–4.8 M of released C-terminal d-alanine (d-Ala) residue/1 culture supernatant per minute. Saccharopolyspora erythraea mutants produced considerably higher levels of exocellular enzymes, the dynamics of excretion depending upon the medium used. The highest activity of exocellular dd-carboxypeptidase production was 44 M d-Ala/1 culture supernatant per minute. The affinity of exocellular dd-carboxypeptidase of S. erythraea 64-575 for -lactam antibiotics was assessed by a statistical computer programme. The enzyme showed the lowest affinity for sodium cefotaxime, ID₅₀(M) = 7.5 × 10^–6, and the highest for potassium cephalosporin C, ID₅₀(M) = 5.0 × 10^–9, ID₅₀(M) representing the molar concentration of -lactan antibiotics which decreased by 50% the release of d-Ala. Offprint requests to: W. Kurzatkowski     

Kinetics of growth and lactic acid production in continuous and batch culture

Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara     

Cloned T cells recognize Trichinella spiralis antigen in association with an Ek βEk α restriction element

A method is described for the production of T-cell lines and clones specific for solubilized Trichinella spiralis antigens. hese T cells are antigen-specific and do not respond to challenge with a third party antigen (lysozyme). The proliferation responses of the cloned T cells are specifically inhibited by anti-I-E but not by anti I-A subregion monoclonal reagents. The inhibition patterns obtained are consistent with cis-gene complementation in B10.K cells involving the E^k -chain and the E^k -chain of the I-E molecule. Inhibition is obtained with an E^k -specific monoclonal antibody (H9-14.8) but not with an A^k -specific monoclonal antibody (10-2.16). Inhibition was also observed with Ia.7-specific (H40-242) or Ia.22-specific (17-3-3) monoclonal antibodies. The inhibition patterns were confirmed by antigen presentation experiments using recombinant inbred mice. Only B 10.K (E^k E^k spleen cells and not B 10.A(5R) (E^b E^k ) or B10.S(9R) (E^s E^k ) spleen cells could effectively present T. spiralis antigens. The role of hybrid Ia molecules in the immune response to T. spiralis is discussed.     

Cycling aggregation patterns of cytoplasmic F-actin coordinated with oscillating tension force generation

Summary Isometric contracting protoplasmic veins of Physarum polycephalum show cycling patterns of cytoplasmic F-actin, dependent on their oscillating contraction behaviour (minute rhythms). The process of fibrillogenesis represents a parallel arrangement of F-actin chains (plasma filaments, microfilaments) during the isometric contraction phase. A part of the results of the present work corroborates previous results on stretch-activated veins which showed that the fibrillar form of F-actin reflects the isometric contracted state.During isometric relaxation phase, a disaggregation of the fibrillar pattern takes place and is accompanied by a deparallelisation of F-actin chains. Therefore, the isometric relaxed state of cytoplasmic actomyosin is non-fibrillar in nature. Thus, the morphologically detectable fibrillar form of cytoplasmic actomyosin, according to physiological interpretation, is solely representative of the isometric contracted state.The question whether assembly-disassembly processes, e.g. GF-actin-transformation, play a role in the contraction-relaxation cycle is discussed.Dedicated to Prof. Dr. Dr. h.c. W. Bargmann on the occasion of his 70 birthday. — Paper presented at the Cell Surface Project Group workshop Interrelation of cell surface and cell locomotion, European Organization for Research on Treatment of Cancer (EORTC), June 6–8, 1975, Zürich, Switzerland.     

Coexistence of cytoplasmic and nuclear genes for male sterility in Petunia

Summary Cytoplasmic male sterility (cms) and nuclear male sterility (nms) in Petunia were described respectively as possible autonomous and integrated states of the same genetic element by Frankel (1971). In the present study we describe genetic analysis of the interaction between the cms, the nuclear gene for male sterility (e) and the fertility restorer allele (Rf). The main findings in this study are: (1) The nuclear sterility allele can coexist in one or two dosages with the cytoplasmic male sterility elements (ste) in somatic cells or female gametes; (2) the presence of the fertility restorer allele Rf is not required for the coexistence of ste and e and (3) Rf does not interact epistatically with e, e.g., the expression of e is independent of Rf—the genotypes (S) RfRfee and (S) Rfrfee are male sterile.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel. 1983 series No. 846 E     

Biofeedback of alveolar carbon dioxide tension and levels of arousal

This is a preliminary study designed to investigate the potential usefulness of alveolar (lung) CO₂ feedback training in promoting sleep onset in primary insomniacs. The present study was undertaken to determine if normal subjects could, without obvious manipulation of breathing, bring alveolar (lung) CO₂ tension under voluntary control using biofeedback techniques and, if so, whether this control would be accompanied by shifts in level of wakefulness. Subjects participated in five baseline and five training sessions in which EEG, alveolar CO₂ tension, and thoracic/abdominal respiratory movement were monitored. The feedback consisted of a pitch-modulated tone plus visual scores. We found that CO₂ tension in awake portions of up trials was significantly higher than for awake portions of down trials (p<.01), indicating that learning had occurred. In the initial trials, when subjects raised CO₂ tension they became drowsy and often fell asleep, and when they lowered CO₂ tension they aroused themselves. However, when subjects were awakened immediately upon falling asleep, there developed a decoupling of EEG and CO₂ changes. The presence of such a decoupling phenomenon makes it unclear whether CO₂ feedback will be useful in promoting sleep onset in primary insomniacs.This study was supported by National Institute of Mental Health Research Fellowship MH05151, Research Grant MH29369, Research Scientist Development Award MH38897, and by a Biomedical Research Support Grant to Langley Porter Institute, 507RR05755.     

Variant forms ofα-2-l-fucosyltransferase in human submaxillary glands from blood group ABH “secretor” and “non-secretor” individuals

The properties of the -2-l-fucosyltransferases in submaxillary gland preparations from blood group ABH secrefors and non-secretors were compared. The level of activity in the non-secretor gland homogenates amounted to about 5% only of that found in the secretor gland preparations. The enzymes from the two sources differed in solubility properties, charge and affinities for donor and acceptor substrates. The enzyme from secretor glands showed a preference for acceptors with Type 1 [d-galactosyl(1–3)-N-acetyl-d-glucosamine] structures whereas the enzyme from non-secretor glands had a preference for Type 2 [d-galactosyl(1–4)-N-acetyl-d-glucosamine] structures.These results demonstrate that expression of the secretor gene (Se) is associated with a molecular form of the -2-l-fucosyltransferase that is different from the species present in the same tissue when theSe gene is not expressed.     

Biofeedback and progressive relaxation treatment of sleep-onset insomnia

Previous research suggests that self-defined insomniacs are distinguished from normals by high levels of anxiety and physiological arousal, which might be mitigated by muscle relaxation. This study assessed the relative effects of frontal EMG biofeedback, progressive relaxation, and a placebo set of relaxation exercises on the sleep of 18 onset insomniacs. Each subject was trained in one of these three methods for six half-hour sessions and slept in the laboratory for two consecutive nights before and after training. The experimental groups demonstrated significant decreases in physiological activity during training while changes in the control group were minimal. Reductions in sleep-onset time were: biofeedback group, 29.66 minutes; progressive relaxation group, 22.92 minutes; control group, 2.79 minutes. The experimental groups improved significantly(p<.05) more than the control group, but did not differ from each other. No significant relationships between physiological levels and sleep-onset time were found, which suggests that muscle relaxation alone was not responsible for subjects' improvements. Since 20 minutes of daily practice were required to achieve an approximate 30-minute decrease in sleep-onset time, the practical utility of the methods is questioned.Portions of this paper were presented at the 15th Annual Meeting of the Association for the Psychophysiological Study of Sleep, Edinburgh, July, 1975, and at the 6th Annual Meeting, Biofeedback Research Society, Monterey, California, February, 1975.     

Turbulent breakage of protein precipitates in mechanically stirred bioreactors

Experimental data relating to the breakage of isoelectric Soya protein precipitates in a mechanically agitated bioreactor are provided and examined in the light of a proposed mechanistic model which relates the size of the maximum attainable aggregate diameter to the energy dissipation rate in the vessel. The analysis suggests that protein precipitation results in the formation of scale-invariant fractal aggregates with a dimensionality of 2.2. Comparing the fractal dimensionality of the protein precipitates with reported values based on computer simulation studies suggests that the aggregates undergo considerable restructuring during agitation.List of Symbols A Hamaker constant (J) - D impeller diameter (m) - d _p primary particle diameter (m) - d _f maximum aggregate diameter (m) - G shear rate (s^–1) - H ₀ separation distance between two primary particles (m) - k constant in Eq. (5) - K constant in Eq. (6) - N impeller speed (rpm or rps) - r radial position in an aggregate, measured from the centre (m) - t time of exposure to shear (mins) - T _e eddy period (s^–1) - v _f aggregate volume (m³) Greek Symbols aggregate dimensionality constant - energy dissipation rate (W/kg) - dynamic viscosity of particle-free liquid (kg/ms) - kinematic viscosity of particle-free liquid (m²/s) - collision probability (–) - _p aggregate density (kg/m³) - _p continuous phase density (kg/m³) - aggregate mechanical strength (N/m²) - shear stress (N/m²) - particle concentration in an aggregate (m³/m³) - (r) porosity at radial position, r     

HLA class II alleles and measles virus-specific cytokine immune response following two doses of measles vaccine

Measles virus-specific T cells and the production of cytokines play a critical role in the immune response following measles immunization. To understand the genetic factors that influence variation in IFN- and IL-4 responses following measles immunization and to provide insight into the factors influencing both cellular and humoral immunity to measles, we assessed associations between human leukocyte antigen (HLA) class II genes and measles-specific Th1 and Th2-type cytokine responses in peripheral blood lymphocytes from 339 children previously vaccinated with two doses of measles-mumps-rubella vaccine (MMR-II). Median values for measles-specific IFN- and IL-4 secretion levels were 40.73 and 9.71 pg/ml, respectively. The global tests suggested associations between measles-specific IFN- response and alleles of the DRB1 and DQB1 loci (P=0.07 and P=0.02, respectively). Specifically, DRB1*0301, *0901, and *1501 alleles were significantly associated with IFN- secretion. The alleles that suggested evidence of an HLA association with IL-4 secretion were DRB1*0103, *0701, and *1101. Th1 cytokine responses and DQB1 allele associations revealed that the alleles with the strongest association with IFN- secretion were DQB1*0201, *0303, *0402, and *0602. Specific alleles with a suggestive association with low measles-specific Th2 cytokine responses were DQB1*0202 and *0503. In addition, DPB1*0101, *0201, and *0601 alleles provided suggestive evidence of an HLA association with measles-induced IFN- response, while DPB1*0501 was associated with an IL-4 response. These data suggest that IFN- and IL-4 cytokine responses to measles may be genetically restricted in part by HLA class II genes, which in turn can restrict the cellular immune response to measles vaccine.     

Continuous functions determined by spike trains of a neuron subject to stimulation

several ways of estimating a continuous function from the spike train output of a neuron subjected to repeated stimuli are compared: (i) the probability of firing function estimated by a PST-histogram (ii) the rate of discharge function estimated by a frequencygram (Bessou et al. 1968) and (iii) the interspike-interval function which is introduced in this paper. For a special class of neuronal responses, called deterministic, these functions may be expressed in terms of each other. It is shown that the current clamped Hodgkin-Huxley model of an action potential encoding membrane (Hodgkin and Huxley 1952) is able to generate such deterministic responses. As an experimental example, a deterministic response of a primary muscle spindle afferent is used to demonstrate the estimation of the functions. Interpretability and numerical estimatability of these spike train describing functions are discussed for deterministic neuronal responses.     

Characterization of the effectors required for stable inheritance of Streptococcus pyogenes pSM19035-derived plasmids in Bacillus subtilis

The low-copy-number and broad-host-range pSM19035-derived plasmid pBT233 is stably inherited in Bacillus subtilis cells. Two distinct regions, segA and segB, enhance the segregational stability of the plasmid. Both regions function in a replicon-independent manner. The maximization of random plasmid segregation is accomplished by the recombination proficiency of the host or the presence of the pBT233 segA region. The segA region contains two open reading frames (or) [ and ]. Inactivation or deletion of or results in SegA^– plasmids. Better than random segregation requires an active segB region. The segB region contains two ors (or and or). Inactivation of either of the orfs does not lead to an increase in cell death, but or^– plasmids are randomly segregated. These results suggest that pBT233 stabilization relies on a complex system involving resolution of plasmid oligomers (segA) and on the function(s) encoded by the segB region.     

(T2AG3)n Telomeric Sequence Hybridization Indicating Centric Fusion Rearrangements in the Karyotype of the Rodent Oryzomys Subflavus

Chromosome preparations of 30 specimens of Oryzomys subflavus trapped in eight Brazilian localities were C-, and G-banded and analyzed by fluorescence in situ hybridization (FISH). Two karyotypes were found, 2n=50/FN=64, at three coastal localities of the Atlantic Forest domain, and 2n=58/FN=70 at two sites located in the Cerrado biome, Brazil Central. Two fluorescence in situ hybridization (FISH) patterns of the telomeric sequence (T₂AG₃)_n were observed: in both karyotypes the probes hybridized to the telomeres of all chromosomes and also a hybridization signal in the centromeric regions of two autosome pairs was seen in the 2n=50 karyotype. These results, together with the occurrence of other diploid numbers described in the literature, suggest that O. subflavus is a complex species, bearing fusion/fission rearrangements proper to the different biomes which it inhabits.