EEG and behavioral changes in a hyperkinetic child concurrent with training of the sensorimotor rhythm (SMR)

Reduced seizure incidence coupled with voluntary motor inhibition accompanied conditioned increases in the sensorimotor rhythm(SMR), a 12–14 Hz rhythm appearing over rolandic cortex. Although SMR biofeedback training has been successfully applied to various forms of epilepsy in humans, its potential use in decreasing hyperactivity has been limited to a few cases in which a seizure history was also a significant feature. The present study represents a first attempt to explore the technique's applicability to the problem of hyperkinesis independent of the epilepsy issue. The results of several months of EEG biofeedback training in a hyperkinetic child tend to corroborate and extend previous findings. Feedback presentations for SMR were contingent on the production of 12–14-Hz activity in the absence of 4–7-Hz slow-wave activity. A substantial increase in SMR occurred with progressive SMR training and was associated with enhanced motor inhibition, as gauged by laboratory measures of muscular tone(chin EMG) and by a global behavioral assessment in the classroom. Opposite trends in motor inhibition occurred when the training procedure was reversed and feedback presentations were contingent on the production of 4–7 Hz in the absence of 12–14-Hz activity. Although the preliminary nature of these results is stressed, the subject population has recently been increased to establish the validity and generality of the findings and will include the use of SMR biofeedback training after medication has been withdrawn.This research was a segment of the junior author's dissertation research.     

Noninvasive measurements of transmural myocardial metabolites using 3-D (31)P NMR spectroscopy

A completely noninvasive three-dimensional (3-D) static magnetic field magnitude spatially localized (31)P spectroscopy technique has been developed and applied to study the in vivo canine myocardium at 9.4 T. The technique incorporates both Fourier series windows and selective Fourier transform methods utilizing all three orthogonal gradients for 3-D phase encoding. The number of data acquisitions for each phase-encoding step was weighted according to the Fourier coefficients to define cylindrical voxels. Spatially localized (31)P spectra can be generated for voxels of desired location within the field of view as a postprocessing step. The quality of localization was first demonstrated by using a three-compartment phantom. The technique was then applied to in vivo canine models and yielded (31)P cardiac spectra with an excellent signal-to-noise ratio. The in vivo validation experiments, using an implanted 2-phosphoenolpyruvate-containing marker, demonstrated that the technique is capable of measuring at least two transmural layers of left ventricular myocardium representing the subepicardium and subendocardium.     

On the pressure response of Eurydice sp. (Isopoda)

Eurydice responds to increased pressure within the 67 to 790 mb range by an upward swimming, the duration of the response being dependent on the magnitude of the pressure change. Release of pressure is followed by downward swimming or passive sinking.

The responses are orientated primarily to gravity, but with a subsidiary photic influence, and brief pulses of 1–2 sec duration are less effective in eliciting a response.

Adaptation to sustained high pressure appears to involve a shift in the stimulus/response curve with no evident loss of sensitivity.

The pattern of swimming behaviour observed following sinusoidal pressure cycles suggests that, over the range of cycles studied, the parameter most effective in inducing the response is change of pressure, or perhaps pressure itself, rather than the velocity component of the stimulus.

Pressure perception is not affected by surface active substances, nor by changes in sea water concentration, suggesting that the process of transduction does not involve compression of a hydrogen gas film on the body surface.     

A database and tools for 3-D protein structure comparison and alignment using the Combinatorial Extension (CE) algorithm

The database reported here is derived using the Combinatorial Extension (CE) algorithm which compares pairs of protein polypeptide chains and provides a list of structurally similar proteins along with their structure alignments. Using CE, structure-structure alignments can provide insights into biological function. When a protein of known function is shown to be structurally similar to a protein of unknown function, a relationship might be inferred; a relationship not necessarily detectable from sequence comparison alone. Establishing structure-structure relationships in this way is of great importance as we enter an era of structural genomics where there is a likelihood of an increasing number of structures with unknown functions being determined. Thus the CE database is an example of a useful tool in the annotation of protein structures of unknown function. Comparisons can be performed on the complete PDB or on a structurally representative subset of proteins. The source protein(s) can be from the PDB (updated monthly) or uploaded by the user. CE provides sequence alignments resulting from structural alignments and Cartesian coordinates for the aligned structures, which may be analyzed using the supplied Compare3D Java applet, or downloaded for further local analysis. Searches can be run from the CE web site, http://cl.sdsc.edu/ce.html, or the database and software downloaded from the site for local use.     

Validation of a novel secretion modification region (SMR) of HIV-1 Nef using cohort sequence analysis and molecular modeling

The HIV-1 accessory protein Nef plays an active role in the pathogenesis of AIDS by its numerous cellular interactions that facilitate the release of virus particles. This 27?kDa protein is required for maintenance of the viral replication in HIV, and is also known to contribute to immune evasion, blocking of apoptosis in virus-infected cells and enhancement of virus infectivity. Nef has been shown to be secreted and is present on the surface of virus-infected cells. Recent studies from our laboratory have shown that the Nef protein is secreted from nef-transfected and HIV-1-infected cells in small exosome-like vesicles (40-100?nm diam.) that do not contain virions. We have identified three amino-terminal domains of Nef as necessary for secretion: (i) the four arginine residues (17,19,21, 22) comprising the basic region; (ii) the phosphofurin acidic cluster sequence (PACS) composed of four glutamic acid residues (61-64); (iii) a previously unknown motif spanning amino acid residues 65-69 (VGFPV) which we named the secretion modification region (SMR). In this study, we have used population-based phylogeny data and sequence analysis to characterize the conservation of the Nef SMR domain that regulates vesicle secretion. We have performed in silico computational chemistry analysis involving molecular dynamic structure modeling of mutations in the SMR motif. Sequence analysis of Nef from HIV-1-infected patients, including slow progressors (SP), long term progressors (LTP) and long term non-progressors (LTNP) demonstrated 99?% conservation of the Nef SMR motif. Computational analysis including modeling of wild-type HIV-1 Nef and V66A Nef SMR mutant using structural homology and molecular dynamics of ligand-associated interactions indicated significant structural changes in the Nef mutant, thus supporting the importance of the SMR domain for mediating Nef vesicle secretion.     

Measurement of spontaneous motor activity by using the vibrator response method in rats

To investigate the usefulness of spontaneous motor activity (SMA) measurement using the vibrator response method, the acute effects of drugs on SMA were observed in Sprague-Dawley male rats. There were no significant differences between four devices. Methamphetamine (0.3-1 mg/kg, i.p.) and 1-2 mg/kg (s.c.) of apomorphine increased the SMA, but 0.05-0.2 mg/kg (s.c.) of apomorphine decreased the SMA. Apomorphine at 1-2 mg/kg (s.c.) significantly increased the SMA when the vibrator response method was used as compared with the Animex method. These results suggest that the vibrator response apparatus is useful for the measurement of SMA in rats.     

Validation of subject-specific musculoskeletal models using the anatomical reachable 3-D workspace

A novel metric for the validation of musculoskeletal models is proposed, the reachable 3-D workspace (RWS). This new metric was used to compare a generic model scaled in a standard manner to a more subject-specific model. An experimental protocol for assessing the RWS was performed by ten participants for four distinct hand-payload cases. In addition, isometric individual strength measurements were collected for 12 different directions. The strength of subject-specific musculoskeletal models was then computed using the following assumptions: (1) standard routines including the length-mass-fat (LMF) scaling law; (2) the isometric strengths of the muscle elements were optimized to the individual strength measurements using joint strength factors (JSF). The RWS of each participant was subsequently estimated from each of the scaling approaches, LMF and JSF, for the four load cases. The experimental RWS showed that the volume and shape decreased with increasing hand-payload for every participant. The lateral and frontal far-from-torso aspects of the RWS were reduced the most. These trends were reproduced by both strength scaling approaches, but the LMF-scaled models were not able to track the overall RWS volume decrease with increasing payload, since they proved to be weaker than the participants. On the other hand, the optimised JSF subject-specific models performed better on the prediction of the RWS for all payload cases across participants. The RWS can potentially be further used as a subject-specific musculoskeletal model validation, enabling quantification of the volume and shape differences between experimentally and model-predicted RWSs.     

Enzymatic synthesis and 3-D structure of anti-proliferative acidic (MeGlcUA) xylotetrasaccharide

Anomerically free acidic xylo-oligosaccharides have shown interesting biological properties when tested against Gram-positive and Gram-negative aerobically grown bacteria, as well as against Helicobacter pylori, sarcoma-180 and other tumors. We report here a structure–activity relationship study on the role of 4-O-methyl glucuronic acid (MeGlcUA) in regulating aggregation of β-polyxylosides of (9H-fluoren-9-yl)- methanol obtained via the action of Thermotoga neapolitana xylanase. Neutral compounds from mono- to penta-β-1,4 xylosides were obtained from this biocatalyzed reaction. In addition, acidic components among products, carrying an α-1,2 4-O-methyl glucuronic acid (MeGlcUA) were also isolated. An anti-proliferative test of these compounds on human epithelial EFO 27 ovarian cancer cells indicated that the presence of MeGlcUA modulates their biological activity, while its absence induces molecular aggregation. The three-dimensional structure of the most active MeGlcUA β-polyxyloside was investigated by resorting to NOESY experiments supported by dynamic force-field calculations with/without constraints. The 3D structure is characterized by all sugars possessing a ⁴C₁ chair conformation. The MeGlcUA moiety, and the external and middle xyloses adopt a hairpin-shaped conformation, generating a non-planar arrangement of the molecule with the aromatic ring folding back toward the carbohydrate chain. Such a non-planar conformation may justify the lack of aggregation.     

Investigation of the antibacterial activity of 3-O-octanoyl-(-)-epicatechin

Aims: To measure antibacterial activity of the semi-synthetic flavonoid 3-O-octanoyl-(–)-epicatechin and investigate the mechanism of action. Methods and Results: MICs determined by the broth microdilution method were 50 μg ml⁻¹ for β-lactam sensitive and resistant Staphylococcus aureus, and 100 μg ml⁻¹ for vancomycin sensitive and resistant enterococci. In time-kill studies, 100 μg ml⁻¹ 3-O-octanoyl-(–)-epicatechin reduced colony forming unit numbers of antibiotic sensitive and methicillin-resistant Staph. aureus below detectable levels within 120 min. Bacterial aggregation was not observed when cells exposed to 3-O-octanoyl-(–)-epicatechin were examined by light microscopy. It was also shown that 50 μg ml⁻¹ 3-O-octanoyl-(–)-epicatechin is capable of reducing colony forming unit numbers of high cell density Staph. aureus populations by 80-fold within 60 min incubation, and inducing leakage of 50% of their internal potassium within just 10 min. Conclusions: 3-O-Octanoyl-(–)-epicatechin is active against Gram-positive bacteria, has bactericidal activity against both antibiotic sensitive and resistant strains, and is likely to exert its primary antibacterial effect by damaging the cytoplasmic membrane. Significance and Impact of the Study: 3-O-Octanoyl-(–)-epicatechin has significant antibacterial activity and additional structural modification and/or formulation studies may allow this to be potentiated.     

The anal scent sacs of the otter (Lutra Intra)

This paper describes the structure of the otter anal scent sacs. The deposited secretion contains apocrine gland protein and polymucosaccharide and sebaceous gland lipid. Chemical analyses by gas-liquid chromatography and acrylamide gel electrophoresis revealed individual differences in the composition of secretion. The individual differences in protein bands as revealed by electrophoresis were stable with time and may be useful in following the movements of wild otters in the field.
A captive pair of otters produced deposits of secretion with a periodicity similar to that of the female oestrous cycle, with both sexes producing deposits around oestrus.     

Research on the ultrastructure and function of the anal organ of the normal and lethal (l(3)tr) larvae of the Drosophila melanogaster

The anal organ of larvae of the wild type and the mutant ‘lethaltranslucida’ (l(3)tr, 3–20±0·8) of Drosophila melanogaster was studied by electron microscopy. By means of cryoscopy and microtitration the total osmotic concentration and the chloride content of the haemolymph were also determined. In addition, the effects of hypotonic and hypertonic solutions on the anal organs and the haemolymph concentration have been analysed in detail. We were especially interested in the functional significance and a possible disturbance of these anal organs in the lethal mutant.On the basis of the following characters the anal organ appears as a typical absorption organ: (a) The cuticle is distinctly thinner than that of the remaining body parts and has an enlarged surface by forming numerous porous infoldings. (b) On the cuticular surface the plasma membrane of the singlelayered epidermal cells forms a large number of folds oriented parallel to each other, resulting in a further increase of the absorption surface. (c) An extensive network of microtubules and a dense population of mitochondria, vacuoles, and vesicles in the cytoplasm suggest that an active transport process takes place in this organ.After 1 hr in a strong hypotonic solution (distilled water) the plasma membrane folds of both +/+ and l(3)tr larvae increase and penetrate deeper into the epidermal cell. The mitochondria also increase in number and are located between the apical folds. Conversely, in a hypertonic solution (1·42–11·96% NaCl) the plasma membrane folds become shorter and fewer in number. The mitochondrial density decreases. With increasing salinity and duration various unidentified bodies, degenerated mitochondria, and vesicles appear, indicating the beginning of autolysis.The osmotic concentration of 4-day-old +/+ larvae is found to be 1·02% NaCl, whereas that of l(3)tr larvae of a corresponding physiological age (5 days old) amounts to only 0·65% NaCl. Both genotypes are able to regulate the osmotic concentration in a hypotonic solution; the upper limit of salt concentration of the surrounding medium for a successful regulation is 5 per cent.The chloride concentration of +/+ larvae aged 4 days is found to be 0·19% NaCl, and that of l(3)tr larvae of a corresponding physiological age 0·14% NaCl. In a hypotonic solution both genotypes are capable of regulating the chloride concentration. However, this fails in a hypertonic medium with a concentration higher than 1% NaCl. When the anal organs are blocked by AgNO₃ impregnation, the regulatory ability breaks down completely. No distinct difference in the fine structure as well as in the regulatory achievement of the anal organs between the wild type and the l(3)tr mutant could be detected. It seems that the mutational effect does not lie primarily in a defect of the water balance.     

Assessing the Geometric Structure of a White Clover (Trifolium repens L.) Canopy using3-D Digitising

A method was developed for assessing the three dimensional (3-D)geometric structure of white clover canopies. 3-D co-ordinatesof pre-defined points on leaves, petioles and stolons were measuredusing a Polhemus Fastrak electromagnetic 3-D digitiser. Digitisingprogressed downwards from the top of the canopy and plant partswere removed after they have been digitised. Leaflets were treatedas four quarter-ellipses, and petiole and stolons were treatedas cylinders. Leaf dimensions and areas calculated from 3-Dco-ordinates were within about 5% and 20% of direct measurementsmade with a ruler and a planimeter, respectively. Special softwareand freeware POV-Ray were used to reconstruct a virtual canopyfrom digitiser records and to calculate canopy characteristicssuch as leaf area index (LAI), petiole intersection area, andprofiles of leaflet areas and inclinations with height. It tookbetween 3 and 7 h to digitise 10 x 10 cm stands of clover andthe resulting information was considerably more comprehensiveand accurate than could have been obtained by the alternative‘point quadrat’ or ‘stratified clipping’methods.Copyright 2000 Annals of Botany Company White clover, Trifolium repens, geometric structure, leaf area, leaf angle, 3-D digitising     

The temperature response of C(3) and C(4) photosynthesis

We review the current understanding of the temperature responses of C(3) and C(4) photosynthesis across thermal ranges that do not harm the photosynthetic apparatus. In C(3) species, photosynthesis is classically considered to be limited by the capacities of ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco), ribulose bisphosphate (RuBP) regeneration or P(i) regeneration. Using both theoretical and empirical evidence, we describe the temperature response of instantaneous net CO(2) assimilation rate (A) in terms of these limitations, and evaluate possible limitations on A at elevated temperatures arising from heat-induced lability of Rubisco activase. In C(3) plants, Rubisco capacity is the predominant limitation on A across a wide range of temperatures at low CO(2) (<300 microbar), while at elevated CO(2), the limitation shifts to P(i) regeneration capacity at suboptimal temperatures, and either electron transport capacity or Rubisco activase capacity at supraoptimal temperatures. In C(4) plants, Rubisco capacity limits A below 20 degrees C in chilling-tolerant species, but the control over A at elevated temperature remains uncertain. Acclimation of C(3) photosynthesis to suboptimal growth temperature is commonly associated with a disproportional enhancement of the P(i) regeneration capacity. Above the thermal optimum, acclimation of A to increasing growth temperature is associated with increased electron transport capacity and/or greater heat stability of Rubisco activase. In many C(4) species from warm habitats, acclimation to cooler growth conditions increases levels of Rubisco and C(4) cycle enzymes which then enhance A below the thermal optimum. By contrast, few C(4) species adapted to cooler habitats increase Rubisco content during acclimation to reduced growth temperature; as a result, A changes little at suboptimal temperatures. Global change is likely to cause a widespread shift in patterns of photosynthetic limitation in higher plants. Limitations in electron transport and Rubisco activase capacity should be more common in the warmer, high CO(2) conditions expected by the end of the century.     

Optimization of an extracellular zinc-metalloprotease (SVP2) expression in Escherichia coli BL21 (DE3) using response surface methodology

In this work, SVP2 from Salinivibrio proteolyticus strain AF-2004, a zinc metalloprotease with suitable biotechnological applications, was cloned for expression at high levels in Escherichia coli with the intention of changing culture conditions to generate a stable extracellular enzyme extract. The complete ORF of SVP2 gene was heterologously expressed in E. coli BL21 (DE3) by using pQE-80L expression vector system. In initial step, the effect of seven factors include: incubation temperature, peptone and yeast extract concentration, cell density (OD600) before induction, inducer (IPTG) concentration, induction time, and Ca(2+) ion concentrations on extracellular recombinant SVP2 expression and stability were investigated. The primary results revealed that the IPTG concentration, Ca(2+) ion concentration and induction time are the most important effectors on protease secretion by recombinant E. coli BL21. Central composite design experiment in the following showed that the maximum protease activity (522 U/ml) was achieved in 0.0089 mM IPTG for 24h at 30 °C, an OD600 of 2, 0.5% of peptone and yeast extract, and a Ca(2+) ion concentration of 1.3 mM. The results exhibited that the minimum level of IPTG concentration along with high cell density and medium level of Ca(2+) with prolonged induction time provided the best culture condition for maximum extracellular production of heterologous protease SVP2 in E. coli expression system.     

Investigation of the Gracilaria gracilis (Gracilariales,Rhodophyta) proteome response to nitrogen limitation

Inorganic nitrogen has been identified as the major growth‐limiting nutritional factor affecting Gracilaria gracilis populations in South Africa. Although the physiological mechanisms implemented by G. gracilis for adaption to low nitrogen environments have been investigated, little is known about the molecular mechanisms of these adaptions. This study provides the first investigation of G. gracilis proteome changes in response to nitrogen limitation and subsequent recovery. A differential proteomics approach employing two‐dimensional gel electrophoresis and liquid chromatography–tandem mass spectrometry was used to investigate G. gracilis proteome changes in response to nitrogen limitation and recovery. The putative identity of 22 proteins that changed significantly (P < 0.05) in abundance in response to nitrogen limitation and recovery was determined. The identified proteins function in a range of biological processes including glycolysis, photosynthesis, ATP synthesis, galactose metabolism, protein‐refolding and biosynthesis, nitrogen metabolism and cytoskeleton remodeling. The identity of fructose 1,6 biphosphate (FBP) aldolase was confirmed by western blot analysis and the decreased abundance of FBP aldolase observed with two‐dimensional gel electrophoresis was validated by enzyme assays and western blots. The identification of key proteins and pathways involved in the G. gracilis nitrogen stress response provide a better understanding of G. gracilis proteome responses to varying degrees of nitrogen limitation and is the first step in the identification of biomarkers for monitoring the nitrogen status of cultivated G. gracilis populations.