Natural Biological Systems Research Articles

ASYNCHRONY OF INFECTION TIMING, HABITAT PREFERENCE, AND SYMPATRIC SPECIATION OF SCHISTOSOME PARASITES.

Sympatric speciation, which has been the subject of many theoretical studies based on principally genetic models, requires at least two fundamental conditions; (1) the establishment, through disruptive selection, of a stable polymorphism in a heterogeneous environment; and (2) the of reproductive isolation between the morphs (Maynard Smith 1966; Rice 1984, 1987). Studies of natural biological systems, however, remained restricted to a few taxonomically different groups, predominantly insects. Divergent host races in monophagous insects (Bush 1969; Tauber and Tauber 1989), where habitat diversification and asynchrony in seasonal timing of reproduction was implicated in the restriction of gene flow, have provided the best evidence for nonallopatric speciation. Considering that sympatric speciation was closely linked with a process of habitat (-host) shifts, Price (1980, p. 41) and others emphasized the potential applicability of this process to populations of parasites and stated that if host race formation can lead to speciation of phytophagous insects, it can also be important among animal parasites. It is now well accepted that coevolution of lineages of hosts and parasites (phylogenetic or parallel speciation), where host speciation has been accompanied by divergence of their parasites, is not the only pattern for the of hostparasite associations. Parasites, particularly those whose life cycle involves active dispersion (Combes 1991a), have the opportunity of lateral transfer to unrelated host species, a major feature of parasite evolution (Futuyma and Kim 1987, p. 441). Natural metazoan parasite populations, independently and sympatrically maintained by two or more different hosts, diverging to host-adapted populations have been little studied. Such a situation exists for the trematode Schistosoma mansoni on the Caribbean island of Guadeloupe (1528 kM2), where two species of vertebrate hosts (human and rat) are involved in the transmission dynamics of the parasite.

Preparative and analytical applications of immobilized haemoglobin.

New applications of haemoglobin immobilized on Sepharose 4B are proposed for the removal of cell-free, potentially toxic haemoglobin from either natural biological specimens or artificial haemoglobin-containing systems (e.g., blood substitutes, haemosomes) to be employed for biomedical purposes. In a model study, an affinity column of immobilized haemoglobin was used to remove free haemoglobin from blood serum in which controlled haemolysis had been induced. The affinity column retains all the free haemoglobin, does not retain the haemoglobin-haptoglobin complex(es) and leaves the composition of the serum samples unaltered. When immobilized met-haemoglobin is used, haem is transferred readily to albumin, with which it forms a complex. This observation on the one hand shows that immobilized oxyhaemoglobin should be preferred for preparative purposes, and on the other opens the way to the characterization of the haem transfer reaction to albumin by means of immobilized met-haemoglobin. This reaction is difficult to study in solution owing to the overlap of the met-haemoglobin and methaemalbumin spectra.

The application of a biologically inspired controller to control sound transmission

A biologically inspired control approach for reducing sound transmission through a distributed elastic system has been theoretically and experimentally verified for narrow-band excitation. The control paradigm approximates natural biological systems for initiating movement, in that a low number of signals are sent from an advanced, centralized controller (analogous to the brain) and are then distributed by local rules and actions to multiple actuators (analogous to muscle fiber). A local learning rule that was developed from linear quadratic optimal control theory and solved apriori was implemented. The investigation considered a plate excited by normal plane wave, oblique plane wave, and reverberant acoustic fields. Radiated sound power was the defined cost function and therefore used as the controller error signal. Four control inputs in the form of piezoelectric actuators were mounted on the plate in a two-by-two array. Results indicate that increases in transmission loss of approximately 18 dB are attainable for off-resonance excitation. In general, comparisons of theoretical and experimental data show good agreement. This investigation has demonstrated that the biological control approach has the potential to control multimodal response in distributed elastic systems using an array of many actuators with a reduced order main controller. Thus significant reductions in control system computational complexity have been realized by this approach. [Work supported by NASA Langley.]

Genetics and conservation

The basic sciences of genetics and ecology have long played a vital role in agriculture. New technologies spawning a gene revolution promise to revolutionize agricultural genetics. The opportunities to utilize these new techniques, along with standard methods of animal and plant breeding, are great for agriculture, conservation biology, and their synergism. Biological diversity is inextricably linked to human welfare. Genetic engineering is viewed as having both promise and risk to agricultural and natural biological systems, suggesting that its application must be evaluated on a case-by-case basis. In order to adequately manage genetic resources, patterns of genetic variation must be documented and their relationship to the life-histories of species and the functioning of ecosystems understood. To achieve this goal, species to receive attention must be prioritized, possibly based on their usefulness as indicator species in defining genetic management strategies for biological groups of species. Particular attention should be given to invasive species, to the phenotypic plasticity of species, and the organizational complexity of populations, communities, and ecosystems. A return to greater scientific emphasis at the organismal and ecosystem level obviously is essential.

Time-dynamic quantization of molecular-genetic, photosynthesis and ecosystem hierarchical levels of the biosphere

Structural-functional organization of natural biological systems is founded on the principle of evolutionary accumulation of information and division into separate hierarchical levels. Every hierarchical level has its own basic processes with a specific time-dynamic quantization scheme. The relative information entropy representing quantization schemes forms a widely known sequence of generalized divine section numbers. The product of photosynthesis basic processes is free energy shunted off into various energy-transferring compounds. The product of other basic processes is the matter also distributed between compounds of the product. Such an energy-matter distribution shows the same divine values of relative information entropy as the quantization scheme.

The Conscious Machine and the Quantum Revolution in Information Technology

Pioneering work into Very Large Scale Integration (VLSI) and the theory of computation reveals a new revolution. Quantum physics is essential to the understanding of deuces with two stable states and to how theoretically, classical Turing computation is physically possible. Furthermore, completely novel quantum‐mechanical computational devices utilizing dimensional confinement can be made; similar mechanisms may well exist in natural biological systems and brains. Shows that this new quantum‐mechanical perspective yields the basis for a model of conscious machinery, with correspondingly well defined processes specifying the nature of perception, cognition and information, for which as yet computer science has no agreed definitions.

Chemical sensing, molecular electronics and nanotechnology: Interface technologies down to the molecular scale

Molecular recognition in chemical sensing may be achieved by specific key-lock interactions, as they are known from both, natural biological systems and microstructured man-made devices. To handle the specific detection of molecules or ions reliably, a detailed understanding is required in both cases about the chemical compositions and electronic and/or optical properties of the materials involved, with particular emphasis on their interfaces. Of increasing interest are organic structures with potential future applications in chemical sensing or molecular- and bioelectronic devices. Recent research and development efforts focus at proper choices of prototype materials to be microfabricated, new experimental approaches, adequate theories, reliable technologies in the preparation and modification of materials; and interfaces to produce microstructured devices down to the atomic scale.

Thymosins and anti-thymosins: properties and clinical applications.

For years, scientists have searched for ways to trigger the body's own defenses against cancer and other diseases associated with abnormal immunity. This search has led to the discovery of a number of important new biological and chemical substances that augment, direct or restore many of the normal defenses of the body. These substances are in essence the natural drugs of the body that endow us with immunity and resistance to disease. Now called biological response modifiers (BRMs), most of these 'new medicines', such as thymosins, lymphokines, and interferons, occur naturally in the body, while others, synthetic immunomodulators and thymomimetic agents (drugs that mimic thymic function) have been created in the laboratory. Previously, therapeutic drug development in this area relied upon chemical synthesis or introduction of bacterial adjuvants, or modified viral compounds and substances, which were foreign to the body. Therefore, they did not and do not rely upon or use the body's natural immune and biological response systems for protection against disease, function and response to the environment. Although scientists have known about BRMs for years, isolating and purifying them so that they could be used to treat diseases has been extremely difficult. Many of these substances, such as the lymphokines, occur in the body in minute amounts and normally do not circulate in the blood. The development of new technologies for isolation and large scale synthesis, e.g. solid phase peptide synthesis, high-pressure liquid chromatography microsequencing and genetic engineering, has now permitted scientists to isolate, purify, and synthesize BRMs in sufficiently large quantities to allow human clinical trials. In this paper we will focus on the potential clinical applications of the thymosins and anti-thymosins.

Indirect Control of the Forces of Constraint in Dynamic Systems

In this paper two problems are investigated; how to control a dynamic system such that holonomic constraints are maintained and further the forces of constraint are a priori specified. Two cases of the latter are considered: constant forces of constraint and forces that are functions of the state. The dynamic system is linearized about an operating point and linear feedback is exploited for the solution of both problems. A methodology for computing the feedback gains is developed and applied to a nonhuman biped model that possesses ankle torques in the frontal plane. Simulation results are carried out for the nonlinear biped model to maintain the vertical force of constraint constant under the foot. Applications to locking of joints in natural biological systems is noted.

In vitro energy transfer in Renilla bioluminescence

A quantitative study of in vitro energy transfer in a natural biological system is reported. The in vitro bioluminescent oxidation of Renilla (sea pansy) luciferin by luciferase produces a broad, structureless emission, peaking in the blue at 490 nm. In contrast, the live animal produces a structured emission peaking in the green at 509 nm. This difference in emission characteristics is due to the presence, in Renilla, of a green fluorescent protein (GFP). Addition of GFP in vitro sensitizes the oxyluciferin product excited state, resulting in the narrow, structured green emission characteristic of GFP fluorescence (lambda/sub max/ 509 nm). Under conditions of efficient in vitro energy transfer (2.7 x 10/sup -6/ M GFP) the radiative quantum yield (with respect to luciferin) increases 5.7-fold from 5.3% (blue pathway) to 30% (green pathway). The fluorescence quantum yield of the Renilla GFP has been measured as 30%; thus, within the precision of our measurements (15% coefficient of variation) the in vitro energy transfer efficiency is a surprising 100%.

Interactions between insecticides and soil microbes.

The widespread use of insecticides over the past 30 years has resulted in problems caused by their interaction with natural biological systems. The complex interrelationship of these systems is illustrated in Figure 1. A problem due to contamination by residues may appear far removed from the initial point of introduction into the environment. For example, while some insecticides are intentionally applied directly to the soil to control soil insects, the soil is also a repository for chemicals from drift during foliar application, plant residues containing insecticides and their degradation products, and chemicals deposited by atmospheric precipitation. The persistence of insecticides and their degradation products depends on how deeply they are mixed into the soil; even the most persistent compounds disappear relatively quickly when on the soil surface, yet when incorporated into the soil they are very persistent (Edwards 1966). Generally insecticide residues will occur in the top 6 in. of soil (Chisholm et al. 1950, Harris and Sans 1969, Lichtenstein et al. 1962). This is also the region of greatest activity of soil fauna and flora (Alexander 1961), thus setting the stage for interaction of insecticide residues with the fauna and flora of the soil ecosystem. Recent monographs have considered the effects of insecticides on soil fauna (Edwards and Thompson 1973) and aquatic microorganisms (Ware and Roan 1970).KeywordsSoil MicroorganismSoil MicrobeMethyl ParathionSoil MicrofloraHeptachlor EpoxideThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Treatment of information on living beings: systems with services through successive trials

Information treatment, especially in a natural medium, may be done by a random system: given an input, possible solutions are randomly selected and successively tested until the right one is found and then emitted. This paper is a mathematical study of this type of system and its use as a model of some natural (biological) systems. The theoretical development is illustrated by several examples of possible applications to biological cases. We study, under different assumptions, the distribution of the number of trials needed to treat the input, the distribution of the time for this treatment, and the distribution of the average amount of information treated in a trial or in a unit of time. We consider the case of error, and study some optimal conditions of operation and the occurrence of memory influencing the treatment of an input according to previously processed inputs.

Oxywater-oxenoid conception of mechanisms of benzylpenicillin oxidation and oxidant decomposition in aqueous hydrogen peroxide solution

There are actuality and importance of confirmation or at least reasoned argumentation of molecular kinetics of hydrogen peroxide oxidation reactions because of currently unidentified true nature of oxygen intermediates, at one side, and widespread of these processes in natural biological and artificial anthropogenic systems, from other side. The building of common theory of hydrogen peroxide oxidative activity and dismutation decomposition can be based on determination of structure of individual model reactions products. The benzylpenicillin molecule has a heterofunctional structure. Its sodium salt was dissolved in aqueous hydrogen peroxide solution without Fenton catalysts addition. The system was protected from thermal and photochemical activation. As result, we observed a colloid solution formation, a water-insoluble sediment accumulation, and a hydrogen peroxide disproportionation with gas-phase molecular oxygen liberation. The NMR-spectroscopy data evidenced in favor of S-oxidation of sulfide fragment, N-oxidation of nitrogen atoms with amide groups dissociation, and aromatic ring hydroxylation and electrophilic carbonylation. The precipitate is a mixture of several substances, some of which have presumably an oligomeric structure due to neighboring molecules coupling in carbonylation and hydroxylamine fragments O-acylation reactions. The molecular kinetics of model organic molecule oxidative modifications and hydrogen peroxide dismutation is interpreted by oxywater-oxenoid conception. In accordance with one, there are different associates between water HOH and hydrogen peroxide HOOH molecules in solution system due to hydrogen bonds. These molecules are simultaneously Brønsted acids and bases. The rate of proton accepting and donation depends on temperature and concentration parameters. The hydronium H3O+ and hydroperoxonium H3O2+ cations, and the hydroxide HO− and hydroperoxide HO2− anions are generated. For hydrogen peroxide molecule H2O2, there is possibility for isomeric bipolar ion oxywater H2O+O− formation. The zwitter-ion heterolytically dissociates with water molecule liberation and singlet oxygen atom generation. The 1D-oxene (2p[↑↓][↑↓][_]) oxidizes sulfur and nitrogen heteroatoms through accepting their unshared electron pairs by own vacant atomic orbital. In addition, singlet oxygen atom hydroxylates an aromatic ring by hydride transfer and mediates decomposition of hydrogen peroxide. The dioxygen liberated during hydrogen peroxide dismutation is generated at first in singlet 1∆g-quantum state, the quenching of which, presumably, includes a dimerization of 1O2 antipodes by orbital moment. Inside the associate (1O2)2, the electron exchange interaction occurs. As result, two molecules of triplet dioxygen are generated, and they are antipodes by spin moment: first molecule has spin +1 and second molecule has spin −1.

Commercializing synthetic biology: Socio-ethical concerns and challenges under intellectual property regime

Synthetic biology also termed as ‘genomic alchemy’ represents a powerful area of science that is based on the convergence of biological sciences with systems engineering. It focuses on building, modelling, designing and fabricating novel biological systems using customized gene components that result in artificially created genetic circuitry. As discussed in the present study, synthetic biology is an elegant consequence of amalgamation of various branches of science. It is speculated that the resulting synthetic organisms can successfully provide solutions for the problems where natural biological systems have failed. These artificially synthesized organisms can be tutored to meet diverse applications such as production of various biodrugs and creation of tailor-made metabolic pathways. Evidently, this revolutionary technology has the potential to transform human life directly and indirectly. The article provides an insight into the tremendous commercialization ability of synthetic biology in various sectors (bioenergy, medicine, and so on) as demonstrated by various initiatives, collaborative projects with huge investments. It is noteworthy that synthetic biology tools and organisms can be used for saving, creating ‘or’ destroying life; hence the study further deals with the socio-ethical implications of this rapidly advancing field of biology and also assesses the challenging role of intellectual property regime in commercialization of synthetic biology.

The Relative Biological Effectiveness of 180-Kevp and 22.5-Mevp X-Rays Determined from the Dose-Survival Curve of Saccharomyces cerevisiae

The use of supervoltage X-rays for deep therapy has stimulated interest in the relative biological effectiveness (RBE) of such radiation compared to that conventionally employed (200 to 400 kevp). For betatron X-rays of about 20to 31Mev peak energy, reported RBE values have ranged from 0.4 to 1.0 (1-7); for betatron electron beams of about 3 to 6 Mev, from 0.4 to 1.45 (8). Although this range of values may be due to differences inherent in the nature of biological systems, it may also stem, at least in part, from the limited precision of the methods employed and from differences in the basic concepts underlying the dosimetry, e.g., air (roentgens), tissue dose, and absorbed dose (rads). We have defined the RBE of supervoltage X-rays as the ratio of absorbed dose of standard X-rays (180 kevp) to that of supervoltage X-rays (22.5 Mevp) when both produce the same biological effect. In the present experiments, employing the X-ray beams of the 180-kvp machine and the 22.5-Mev betatron at the SloanKettering Institute, the biological effect was measured in terms of the dose-survival curve of a microorganism. The technical problems involved in the determination