Phenoloxidase activity of acridid grasshoppers from the subfamilies melanoplinae and oedipodinae

• 1.1. Phenoloxidase activity and wound melanization was studied in five species of grasshoppers representing the subfamilies Melanoplinae and Oedipodinae.
• 2.2. Most of the phenoloxidase activity was detected in the plasma fraction of grasshopper whole-body homogenates and supernatant fractions of the hemolymph. The species representing the Oedipodinae had 20–50% higher percentage of the total phenoloxidase activity associated with particulate matter from a whole-body homogenate when compared to the Melanoplinae.
• 3.3. Phenoloxidase activity could not be detected in sclerotized cuticle of adult grasshoppers.
• 4.4. The phenoloxidase existed as a zymogen which could be activated by chymotrypsin and inhibited by KCN and NaCN while EDTA showed no effect. It had optimum activity at 37°C and pH 7.3.
• 5.5. These findings are discussed in relation to wound repair and immune responses to infection in grasshopper species.

     

Cloning and characterization of rabbit pancreatic colipase

• 1.1. Among the digestive enzymes synthesized by pancreas, lipase is the principle lipolytic enzyme which hydrolyses dietary glycerides.
• 2.2. For its action it requires a coenzyme, colipase.
• 3.3. The molecular mechanisms of the interaction of these two are not fully understood.
• 4.4. Further, molecular events that regulate and influence lipid absorption are ill denned.
• 5.5. The rabbit is the conventional animal model for the study of lipid absorption. We have undertaken the molecular cloning, and characterization of rabbit pancreatic colipase, the coenzyme for pancreatic lipase.
• 6.6. Colipase has been cloned from a gt 11 library of an adult rabbit pancreatic cDNA by probing with an oligonucleotide derived from human colipase sequence.
• 7.7. The total reading frame consists of 321 nucleotides coding for 90 amino acids of the functional protein and 17 nucleotides of the leader peptide.
• 8.8. Northern blot analysis revealed a distinct band around 0.5kb. Comparison with other species revealed an over all homology of 75% at the nucleotide level.
• 9.9. At the amino acid level highest conservation is observed at the lipase-binding region (AA 53–73).
• 10.10. Rabbit enzyme also retained the N-terminal pentapeptide of it preform.
• 11.11. The regions of homology and conservation may aid to define the sites of interaction of colipase with lipase.

     

The chemical ecology of Biomphalaria glabrata (say): Sugars as phagostimulants

• 1.1. The buccal-mass responses of the freshwater snail Biomphalaria glabrata to sugars were investigated by means of an olfactometer.
• 2.2. The snails proved very discriminating in their responses. Adults responded significantly to only five (12.2%) of the 41 sugars tested at 10⁻² M. Juvenile conspecifics had a broader niche as they responded to eight (47%) of the 17 sugars tested.
• 3.3. Of all the sugars tested, maltose proved to be the most potent phagostimulant.
• 4.4. The possible mechanisms involved in the chemoreception of active sugars and the ecological relevance of the responses shown by the snails to them are discussed.

     

Physiological costs of combating chemical toxicants: Ecological implications

• 1.1. Evidence is presented that combating the poisoning effects of toxic chemicals is metabotically costly.
• 2.2. This has implications for relating physiological stress responses observed at the level of individual organisms to population effects, and needs to be incorporated explicitly into models making this link.
• 3.3. The cost hypothesis also has implication for the evolution of stress resistance either as a fixed or facultative (inducible) response. Optimization models incorporating these ideas are reviewed and discussed.

     

Presynaptic modulation of sensory afferents in the invertebrate and vertebrate nervous system

• 1.1. Ultrastructural examination of the central terminals of sensory afferent neurons in both invertebrates and vertebrates demonstrates that the synapses that form the substrate for presynaptic inhibition and facilitation are almost universally present.
• 2.2. Presynaptic modulation of afferent input acts in many ways which tailor the inflow of sensory information to the behaviour of the animal, effectively providing a means of turning this on and off, or of combining information of the same or different modalities to refine responsiveness or clarify ambiguity.
• 3.3. Presynaptic modulation may act in several different roles on the same afferent.
• 4.4. A comparison of the mechanisms of presynaptic inhibition in different animals demonstrates the likelihood of a variety of common mechanisms,several of which may act simultaneously on the same terminal.These include changes in the conductance of the afferent membrane to Cl^-, K⁺and Ca²⁺ions, in addition to less well understood mechanisms that directly affect transmitter release.
• 5.5.A single transmitter can produce several effects on a terminal through the same or different receptors.
• 6.6. Ultrastructural studies of afferent terminals reveal that only a proportion of boutons on a given afferent may receive presynaptic input and that this may depend on the region of the nervous system in which these are found or on the identity of the postsynaptic neurons contacted.
• 7.7. The synaptic relationships of afferent terminals can be complex. In invertebrates different types of presynaptic neuron may interact synaptically,as may postsynaptic dendrites in vertebrates.
• 8.8. Axons presynaptic to afferent terminals in vertebrates frequently synapse also with dendrites postsynaptic to the afferents.
• 9.9. In both invertebrates and vertebrates reciprocal interactions between afferents and postsynaptic neurons are seen.
• 10.10. Ultrastructural immunocytochemistry reveals the likely dominance of GABA as an agent of presynaptic inhibition but also demonstrates the possible presence of other transmitters some of whose roles are less completely understood.

     

Relationship between ecg,eeg and sps responses during arousal in the goldfish (Carassius auratus)

• 1.1. Goldfish (Carassius auratus) were fitted with ECG electrodes and intra-cranial stainless steel electrodes to monitor cardiac, EEG and SPS responses, during minimal restraint, to presentation of environmental stimuli (light-on, moving shadow, tap).
• 2.2. All three stimuli evoked a bradycardia and increases in the EEG frequency; correlates of arousal responses in fish.
• 3.3. EEG frequency changes were most evident in the fore- and midbrain regions; in the hindbrain smaller responses nevertheless showed discrimination between stimuli.
• 4.4. EEG amplitude changes were more site- and stimulus-specific than frequency changes.
• 5.5. SPSs occurred on stimulus presentations which were negative in polarity in the midbrain and positive in the forebrain and hindbrain, though the latter were smaller and less consistent.
• 6.6. Principal components analyses and regression analyses were used to examine detailed associations between peripheral and central physiological changes.
• 7.7. It was found that increases in the EEG frequency of fore- and midbrain regions were related to cardiac deceleration on early stimulus presentations.
• 8.8. This was also shown for the negative SPS of the midbrain to the presentation of the tap stimulus.
• 9.9. Positive SPSs of the forebrain were related to the bradycardia on later stimulus presentation i.e. during habituation of the arousal response.
• 10.10. The results indicate that in fish, as in other vertebrates, negative SPSs in the midbrain are associated with arousal and implicate the forebrain in the modulation of arousal by its habituation.

     

Application of electrical analogs to metabolic control analysis: Linear pathways with multiple feedback

• 1.1. Using electrical analogs, we have presented a systematic procedure for calculating the flux control coefficients of linear metabolic pathways with multiple feedback loops.
• 2.2. In this method, an electrical analog circuit is constructed first for the unregulated pathway.
• 3.3. This circuit is subsequently modified in a step-by-step fashion to take into account the effect of each feedback loop in the pathway.
• 4.4. An analog circuit consists of resistances which are connected in series (or parallel) with a voltage (or current) source.
• 5.5. The flux control coefficients of the enzymes are represented by voltages across (or currents through) the resistances and are determined by an application of Ohm's law.
• 6.6. We have investigated the possible patterns in linear pathways with two feedback loops.
• 7.7. This is followed by an analysis of a linear pathway with an arbitrary pattern of feedback inhibition.

     

HLA-DO Modulates the Diversity of the MHC-II Self-peptidome

1. Download : Download high-res image (171KB)
2. Download : Download full-size image

Highlights

• •MHC-II-bound peptide repertoires from DO-sufficient and DO-deficient cells.
• •Fewer unique peptides and core epitopes were presented in the absence of DO.
• •Immunopeptidome differences appeared to result from reduced DM editing.
• •DO-dependent self-epitopes elicited CD4 T cell responses in mice.

     

Significance of scrotal afferents within the general thermoafferent system

• 1.1.|Switching neurons, in the past referred to as a special scrotal afferent system, intergrate information not only from the scrotum, but from various body areas.
• 2.2.|They are present in male and female rats, as well as in guinea-pigs.
• 3.3.|They are present in midbrain, thalamus, hypothalamus and cortical areas.
• 4.4.|Information processing from the scrotum, is not a special system, but part of the general thermo-and noci-afferent system.
• 5.5.|Switching neurons seem to interact with behavioral, perhaps with autonomic thermoregulatory mechanisms, too.

     

Induction kinetics of immune antibacterial proteins in pupae of Galleria mellonella and Pieris brassicae

• 1.1. Pupae of Galleria mellonella and Pieris brassicae given an injection with live, non-pathogenic Enterobacter cloacae or abiotic foreign molecules induce an acquired immunity that corresponds with the synthesis of haemolymph proteins of antibacterial activity.
• 2.2. This humoral defensive response which persists for several days, differs quantitatively between insect species and between the inducers used, although very different foreign bodies induced the same immune proteins in both lepidopteran insects.
• 3.3. A stronger and longer lasting response was consistently noticed in pupae immunized with non-pathogenic bacterium than after sterile nutrient broth injections.
• 4.4. A demonstrably elevated activity of haemolymph lysozyme and trace activity of cecropins found in pupae of Galleria treated with saline W, a salt solution physiological to moths, disappear soon after 36 hr from injection.
• 5.5. In P. brassicae, however, sterile insect Ringer can give a varying, if present at all, immune response.
• 6.6. A mechanical injury (sterile wounding of insect body) can occasionally induce a similar but much weaker response.
• 7.7. The antibacterial activity was drastically reduced in Pieris or completely depressed in most pupae of Galleria when actinomycin D or cycloheximide was given at an early time post-immunization with E. cloacae.
• 8.8. It is concluded that the de novo synthesis of ribonucleic acid and immune proteins is required for expression of antibacterial activity in pupal haemolymphs.
• 9.9. The synthesis of an immune mRNA was completed about 7 hr after the injection of the immunizing bacteria.

     

Effect of bovine milk antigens and egg lysozyme on the binding of 59Fe-lactoferrin to platelet plasma membranes

• 1.1. Platelets bind specifically to lactoferrin. A significant similarity between human lactoferrin and some bovine milk proteins has been established.
• 2.2. Because of the structural homology of lactoferrin and cows milk proteins they are able to influence lactoferrins regulatory function on the level of its binding to membrane receptors on platelets.
• 3.3. An inhibitory effect of bovine α-lactalbumin and of β-lactoglobulin on lactoferrin-receptor interaction was shown.
• 4.4. Bovine α-lactalbumin competes with lactoferrin for the binding sites.
• 5.5. Scatchard plot analysis of data shows one binding site for lactoferrin in the presence of α-lactalbumin with an affinity constant, Ka = 0.46 × 10⁹ mol/1 and 335 receptors/cell.
• 6.6. The inhibitory effect of β-lactoglobulin reaches 62% and is different for the common fraction ⨿-lactoglobulin and the genetic variants β-lactoglobulin A and B.
• 7.7. β-lactoglobulin does not compete with lactoferrin for the membrane receptors.
• 8.8. Bovine casein and egg lysozyme stimulate ⁵⁹Fe-lactoferrin binding to the receptors. The mechanism of these effects is still unknown.
• 9.9. Tested alimentary antigens are able to interact with lactoferrin and also with some platelet membrane structures.
• 10.10. Established changes in lactoferrin binding to the platelet membrane might be in relation to lactoferrins regulatory function and (or) eliminating mechanisms of these alimentary antigens.

     

Company news

Including information on:

• ScanSoft
• SpeechWorks International
• Viisage Technology
• Firstec
• BIO-key International
• HP
• ZN Vision Technologies
• Unisys
• US Government’s
• Communication Intelligence Corporation
• Infinity Technologies

     

Company news

• Daon
• Musicrypt
• EMI Music Canada
• Digital Broadband Networks
• FaceKey Corporation
• Eystar Media Inc (EMI)
• Temasya Wira
• Animated Electronic Industries
• BIO-key International
• Entryport Corporation

     

Metabolic,Anti-apoptotic and Immune Evasion Strategies of Primary Human Myeloma Cells Indicate Adaptations to Hypoxia*

1. Download : Download high-res image (116KB)
2. Download : Download full-size image

Highlights

• •In-depth proteome profiling of primary human myeloma cells
• •Characteristics of myeloma cells are related to hypoxic bone marrow conditions
• •Myeloma cells show specific immune evasion strategies
• •Metabolic adaptations involve tumor and stroma cells

     

The regulation of trematode populations by density-dependent processes

• 1.1. Density-dependent processes act as negative feedback mechanisms and constrain parasite population growth with individual hosts and so regulate the growth of the total population within the community of hosts.
• 2.2. Density-dependent processes exert this effect through the influence they have on the mortality, fecundity, and asexual multiplication rate of the parasite, and regulation is contingent upon a proportional increase in some adverse effect as parasite population size increases.
• 3.3. Mathematical models provide important qualitative insights into the nature and consequences of density-dependent processes.
• 4.4. The physiological mechanisms underlying the observed relationships are frequently difficult to identify, but, insofar as the models are implicit hypotheses about the characteristics of the mechanisms, they provide a template against which to test conflicting ideas.
• 5.5. Density-dependent processes complicate the implementation and assessment of disease control programmes involving anthelminthics and explanatory schemes which ignore their effects are unable to account for or predict the full range of dynamic behaviour of helminth parasite populations.

     

Application news

Including information on:

• Martin State Airport
• Bioscrypt
• Saflink
• Office of the Secretary of Defense
• Department of Defense
• Boeing Corporation
• Bell ID, Gemplus
• Siemens
• Foreign Ministry

     

In brief

• Bioscrypt
• Saflink
• Dell
• Fujitsu Microelectronics America
• Identix
• Viisage
• Acsys Biometrics
• US Government

     

Biodistribution of photosensitizing agents

• 1.1. The features of neoplasia which predict for drug responsiveness are rapid growth and/or inefficient repair of damage, especially to DNA.
• 2.2. PDT has the advantage of yielding responses regardless of the growth fraction of a tumor, and repair appears to play only a minor role.
• 3.3. While an entirely different spectrum of tumors can be targeted with PDT, the perhaps unavoidable accompaniment is that a new set of rules for efficacy will need to be established.
• 4.4. The selectivity of PDT is based on the need for irradiation which can be directed, along with the short tissue half-life of the cytotoxic product, singlet oxygen. Sensitizers which target specific cellular organelles could promote PDT efficacy, if in vitro data (Woodbum et at., 1992b Photochem. Photobiol. 55, 697–704) can be translated into clinical practice.
• 5.5. It remains to be established whether total drug distribution to neoplastic tissues or concentration in specific sub-cellular sites is the more important factor.
• 6.6. Questions relating to the role of biodistribution as a factor in efficacy of PDT sensitizers of photosensitizers remain to be explored. Just as the political cartographers are grappling with changes in territorial boundaries of known lands, we continue to clarify the rules relating to PDT boundaries. In this regard, it is clearly important for determinants of pharmacokinetics and biodistribution to be evaluated and understood.
• 7.7. Once clinical reports on the “second generation” agents are published, we may get a better picture, although it is not unusual for clinical reports to raise more questions than they answer.
• 8.8. It seems safe to conclude that there is nothing “magic” about HPD, and that additional efficacious photosensitizers for PDT can be produced.
• 9.9. If we find that a wide variety of different structures are useful in the clinic, a likely conclusion is that there are multiple mechanisms of tumor localization. Since the nature of neoplasia is so diverse, this possibility should not be surprising.
• 10.10. In view of the finding, cited above, that liposomes show about the same degree of tumor selectivity as does Photofrin, it may be feasible to target any efficient photosensitizer for neoplastic tissues by development of an appropriate delivery system.

     

Human-induced tachycardia in wild and tame mallard (Anas platyrhynchos)

• 1.1. The effect of regular handling on fear reactions was investigated in mallard (Anas platyrhynchos) by exposing six hand-reared and four wild ducks to an approaching human being and recording heart rates with an external ECG device.
• 2.2. All ducks reacted to the approach with tachycardia, but the response was significantly less in tame birds.
• 3.3. Hand-reared females showed less response than males. No sex-linked differences were apparent in the wild ducks.
• 4.4. Decreasing responses throughout the experiments were only found in tame birds.
• 5.5. Fear or stress reactions can apparently be diminished through habituation induced by regular handling.

     

The kinetics of an enzyme catalyzed reaction in the presence of an unstable,irreversible modifier

• 1.1. The chemical modifications of enzymes is a widely used technique to gain information about the number, type and location of aminoacid residues which are essential for activity. A number of these modifiers are unstable in aqueous solutions and act irreversibly.
• 2.2. The kinetics of such systems have previously been studied under assumptions, some of which are either unnecessary or too restrictive.
• 3.3. We replace these assumptions by others which are more realistic and less stringent.
• 4.4. These assumptions allow us to derive analytical expressions for the evolution of all the species involved in the reaction.
• 5.5. From the analytical expression for the time course of the product formation an experimental design and a kinetic data analysis allowing the easy characterization of these systems are suggested.