Co-expression of a prophage system and a plasmid system in Bacillus subtilis

A dual expression system for overexpressing two proteins by a single cell strain has been developed in Bacillus subtilis. This dual expression system combines the phi105MU331 prophage system and a plasmid system within a single cell. Protein expression by the prophage system is heat inducible, while that of the plasmid system is constitutive. Three candidate genes, BPN, BT, and amyE, all of Bacillus origin, were used as test models. Seven strains (BPN, BT, AMY, BS168K, MU331K, BPNK, and BTK) were constructed to investigate the influences of the prophage system and the plasmid system on each other, and to compare the efficiency of the individual expression systems with that of the dual expression system. Individually, the yield of the plasmid system is higher than that of the prophage system, which could be attributed to the constitutive nature of the expression of the plasmid system. Nonetheless, for the dual expression strains, the expression of two enzymes in a single fermentation run can reduce costs in facilities, manpower, and utilities. Fed-batch fermentation of BPNK strains confirmed the feasibility of applying this dual expression system in industrial-scale production.     

Quantification of genetically modified soybeans using a combination of a capillary-type real-time PCR system and a plasmid reference standard

Because the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved genetically modified varieties in many countries, there is a need for a rapid and useful method of GMO quantification in food samples. In this study, a rapid detection system was developed for Roundup Ready Soybean (RRS) quantification using a combination of a capillary-type real-time PCR system, a LightCycler real-time PCR system, and plasmid DNA as the reference standard. In addition, we showed for the first time that the plasmid and genomic DNA should be similar in the established detection system because the PCR efficiencies of using plasmid DNA and using genomic DNA were not significantly different. The conversion factor (Cf) to calculate RRS content (%) was further determined from the average value analyzed in three laboratories. The accuracy and reproducibility of this system for RRS quantification at a level of 5.0% were within a range from 4.46 to 5.07% for RRS content and within a range from 2.0% to 7.0% for the relative standard deviation (RSD) value, respectively. This system rapidly monitored the labeling system and had allowable levels of accuracy and precision.     

Selection of chemotherapy for patient treatment utilizing a radiometric versus a cloning system

From the 1950s to the 1970s, a number of in vitro systems that measured inhibition of glucose metabolism were used to predict the responsiveness of patients' tumors to chemotherapy. In vitro-in vivo correlations were excellent, with true positive predictions ranging from 68% to 96% and true negative predictions of 95% to 100%. The radiometric system is a new in vitro technique that measures the conversion of 14C-glucose to 14CO2. The system already has been utilized to screen prospective new antineoplastic agents for cytotoxicity. The present study was undertaken to determine if the radiometric system might be used to predict correctly the responsiveness of an individual patient's tumor to single-agent or combination-agent chemotherapy. Fifty-six tumor specimens were divided and tested for drug sensitivity in the radiometric system and a conventional human tumor clonning system. Overall, there was a significant correlation between in vitro and in vivo results for the conventional cloning system (P = 0.03). However, there was no significant relationship between in vitro and in vivo results for the radiometric system. The radiometric system consistently failed to predict the tumor's clinical sensitivity to single agents. A radiometric system is not useful in predicting the responsiveness of a patient's tumor to single agent chemotherapy and is not a replacement for the more biologically attractive human tumor cloning system.     

Development of a Computer-Simulation Model for a Plant-Nematode System

A computer-simulation model (MELSIM) of a Meloidogyne-grapevine system is developed. The objective is to attempt a holistic approach to the study of nematode population dynamics by using experimental data from controlled environmental conditions. A simulator with predictive ability would be useful in considering pest management alternatives and in teaching. Rates of flow and interaction between the components of the system are governed by environmental conditions. Equations for these rates are determined by fitting curves to data from controlled environment studies. Development of the model and trial simulations have revealed deficiencies in understanding of the system and identified areas where further research is necessary.     

Data from a Study of a Neuroallergic Family

Migraine and other types of headaches, serous meningites, encephalomyelites related to the employment of serums and vaccines, including Alazhuanin's hemorrhagic encephalitis, acute hemorrhagic encephalitis, parainfectious encephalites, nervous system damage of arthritic origin (primarily chorea minor), vascular diseases of the nervous system in periarteritis nodosa, cerebral thromboangiitis obliterans in Winiwarter-Buerger's disease, serous and toxic neurites and polyneurites, the Guillain-Barre syndrome, Landry's paralysis, polyneurites resulting from treatment with salvarsan and sulfonamides, certain cases of Meniere's syndrome, demyelinating diseases of the nervous system (multiple sclerosis, related acute and chronic disseminated encephalites, encephalitis periaxialis diffusa, and other forms of sclerous leuco encephalites and, finally, epilepsy (1-24) are diseases of the nervous system associated with immune pathology reactions to various antigens (foods, inhalational, medicamental, viral, bacterial and other foreign agents, and autoantigens).     

具有扩散的n-斑块单种群系统的全局稳定性

研究了具有扩散的ｎ－斑块多种环境下单种群非自治模型,在假定该模型所有系数连续有界的情况下,得到了系统全局稳定的充分条件。     

Dynamic stability of a human standing on a balance board

The neuromuscular system used to stabilize upright posture in humans is a nonlinear dynamical system with time delays. The analysis of this system is important for improving balance and for early diagnosis of neuromuscular disease. In this work, we study the dynamic coupling between the neuromuscular system and a balance board—an unstable platform often used to improve balance in young athletes, and older or neurologically impaired patients. Using a simple inverted pendulum model of human posture on a balance board, we describe a surprisingly broad range of divergent and oscillatory CoP/CoM responses associated with instabilities of the upright equilibrium. The analysis predicts that a variety of sudden changes in the stability of upright postural equilibrium occurs with slow continuous deterioration in balance board stiffness, neuromuscular gain, and time delay associated with the changes in proprioceptive/vestibular/visual-neuromuscular feedback. The analysis also provides deeper insight into changes in the control of posture that enable stable upright posture on otherwise unstable platforms.     

Experimental modeling of a novel magnetic confinement system: Galathea with a myxine in the shape of a convex polyhedron

A new type of magnetic confinement system—a Galathea with a myxine in the shape of a convex polyhedron—is proposed. The system was modeled experimentally by passing an RF current through the myxine. On the one hand, the myxine acts as an inductor whose electric field ionizes the gas and, on the other, it acts as an RF magnetic confinement system. A steady-state plasma produced and confined in this system is almost spherical in shape. The electron density and specific (per unit volume) glow intensity of the plasma produced are found to be higher than those in conventional helical inductors.     

Chaperone-assisted folding of a single-chain antibody in a reconstituted translation system

A protein-synthesizing system based on a minimal set of purified components was used to investigate the roles molecular chaperones play in the folding of newly synthesized polypeptides. After we ascertained that this system lacks intrinsic chaperones, the effect of adding chaperones in a co-translational or post-translational manner was directly evaluated. An aggregation-prone single-chain antibody was used as the model nascent chain. The participation of the trigger factor or the DnaK system during translation efficiently increased the level of functional protein that was generated. In addition, both systems also acted as chaperones after translation had been stopped. In contrast, the GroEL/ES system showed little or no co- or post-translational assistance in folding.     

Development of a direct digital-controlled fermentor using a microminicomputer hierarchical system

A computerized fermentation system was developed for use in a research environment. Major goals in the design and construction of the system were flexibility and versatility. Direct digital control is employed for all low-level and high-level control loops. A microminicomputer hierarchical configuration is used to implement this control structure. The microcomputer is also utilized to simplify the interface with the fermentor, both at the hardware and minicomputer software levels. This computerized fermentation system provides accurate data acquisition, excellent control, and flexibility in the fermentation operation.     

Sustainability of Nile tilapia net-cage culture in a reservoir in a semi-arid region

Among the tools used to measure sustainability in aquaculture, sets of indicators allow a holistic view of a system in its social, environmental, and economic dimensions. Approaches that align indicators with models such as the Drivers-Pressure-State-Impact-Response (DPSIR) framework can improve understanding of this sustainability. This study evaluated the sustainability of cage production systems for Nile tilapia in the Santa Cruz Reservoir, to determine whether a set of indicators used with the DPSIR conceptual model was effective to study the sustainability of the system. The 49 indicators used were calculated from information obtained from questionnaires and from monitoring the production system. Sustainability was also modeled and compared with hypothetical scenarios, with different fish stocking densities. The results indicated that the production system is economically feasible, generating profit and distributing income. However, the income generated benefits few people and is not fixed in the community. Environmentally speaking, the system is highly dependent on inputs, especially the nutrients nitrogen and phosphorus, and energy, as well as increasing sedimentation of nutrients in the reservoir. In the social dimension, the venture employs few workers. The modeling showed that the system is potentially sustainable, and that changes in stocking density decreased this sustainability. In summary, the system showed many sustainable features, whereas some others need to be modified to improve the general sustainability.     

Calculation of thermodynamic properties of species from binding of a ligand by a macromolecule

In the absence of experimental methods for determining concentrations of species in protein-ligand binding, it is not possible to determine the thermodynamic properties of species directly. However, this article on a simple reaction system shows that measurements of the average number of oxygen molecules bound at various T, pH and concentrations of molecular oxygen can be used to calculate thermodynamic properties of species. The simple system considered has some of the characteristics of the binding of oxygen by hemoglobin, but it has been simplified so that the method for obtaining thermodynamic information can be clarified. A table of standard thermodynamic properties of species is the most efficient way to store thermodynamic information on a reaction system. All the standard further transformed thermodynamic properties at specified T, pH and concentrations of molecular oxygen, all the standard transformed thermodynamic properties at specified T and pH, and all the standard thermodynamic properties of species at a specified temperature can be calculated. These calculations are based on the fact that the mathematical function for the standard further transformed Gibbs energy of the system contains all the thermodynamic information on the system. These properties are all interrelated by Maxwell equations.     

The expected extinction time of a population within a system of interacting biological populations

The quasi-stationary distribution of a population within a system of interacting populations is approximated by a stochastic logistic process. The parameters of this process can be expressed in the parameters of the full system. Using the diffusion approximation, an expression for the expected extinction time is derived from this logistic process. Since the expected extinction time is expressed in the parameters of the full system, the effect of these parameters on the extinction risk can be easily evaluated, which may be of use for studies in ecology, conservation biology and epidemiology. The outcome is compared with simulation results for the case of a prey-predator system.     

Integration of a barcode reader with a commercial flow cytometer.

This report describes the application and installation of a barcode reader on a standard EPICS Elite flow cytometer. The barcode reader system eliminates keyboard entry of sample information on the cytometer. The system automates the transfer of sample information already present in our laboratory database to the cytometer at run time. The system uses a standard "off-the-shelf" bar code wand with a personal computer keyboard interface and requires no additional software at run time. No typing of sample information is required by the operator at any stage of normal sample operation at the cytometer. All operations are automatically coded into the cytometry software using the macro functions of the software. Tubes are inserted into the tube reader and sample information is transferred automatically into the cytometer. We have found that the system allows rapid and continuous operation of routine clinical and research samples. This automated data entry also reduces the possibility of data input errors.     

Characteristics and detection principles of a new enzyme label producing a long-term chemiluminescent signal

A new enzyme label system is described which is superior to all existing chemiluminescence labels used in immunoassays. The system consists of the enzyme xanthine oxidase with hypoxanthine as substrate. The signal reagent contains perborate, an Fe–EDTA complex and luminol. The enzyme preparation and the signal reagent are very stable upon storage. The main features of the system are a long duration of the chemiluminescent signal (half-life time of 30 hours) and a very low limit of detection (about 3 amol). Possibilities and implications for the use of various measuring system are discussed.     

一类生化系统的稳定性

本文研究一类生化系统的极限环的存在性与唯一性;分析了系统轨线的全局结构,指出了系统在无穷远点处的轨线存在奇异方向;解释了极限环消失的原因．     

On a stochastic model of a molecular genetic system capable of differentiation and reproduction of the initial state

A model of the system, consisting of a cyclic 3-operonic subsystem, related to a 2-operonic trigger by direct and feedback connections, is built. The operons of this system are functionally connected by repressers. The basic postulates are: a) the repressers are stable; b) during cell division each molecule of represser and respective mRNA has equal probability to find itself in any daughter cell. Computer simulation demonstrates that after few cell divisions, analogues of somatic cell, maintaining the system for some successive divisions, and of generative cells, where by the system returns to the initial state, appear. A scheme of molecular genetic control system, producing a lot of different cell types in course of successive cell divisions, is proposed.     

From a homeostatic to a homeodynamic self

Life as an autonomous homeostatic system is discussed. A mechanism that drives a homeostatic state to an autonomous self-moving state is examined with two computational cell models. The mechanism is met with Ashby's ultrastability, where random parameter searching is activated when a system breaks a viability constraint. Such a random search process is replaced by the membrane shape in the first model and by chaotic population dynamics in the second model. Emergence of sensors, motors and the recursive coupling between them is shown to be a natural outcome of an autonomous homeostatic system.     

四环素诱导组织特异性表达系统的构建

如果获得一种可以特异调控基因表达的系统。对于研究某一基因在各个不同发育时期的功能会有很大的帮助。为了控制外源基因在特定的时间和组织内在转基因植物中表达。将四环素诱导元件和花药绒毡层特异表达启动子TA29结合。构建了一个新的系统。通过基因枪将该系统转入烟煤草（Nicotiana tabacumL.cv.Wisconsin38)组织,GUS瞬时表达结果表明,四环素诱导前,没有任何烟草组织染上蓝色,表明该系统不表达;而四环素诱导仅30min后,花药就染上明显蓝色,而且集中在花药绒毡层,其对照子房在四环素诱导前和诱导后均未染蓝色。这些结果表明。该系统既是四环素诱导又是花药绒毡层特异表达的。     

Functional organization of a photoperiodic brain system

The neurofunctional system, which receives a photoperiod, is a photoperiodic brain system. As a part of chronoperiodic system of organism it is involved in perception and transfer of information about the main external Zeitgeber to the peripheral tissues. Such role of photoperiodic system allows it not only synchronize the chronorhythms of different somatic and visceral functions, but also realize the coordination and the modulation of adaptation mechanisms to the stressors influence. The present review is focused on the ways of conduction of photoperiodic information, role of suprachiasmatic nuclei of hypothalamus in endogenous oscillation of chronorhythms and pineal gland as a neuroendocrinal transducer; and also on characteristics of circadian and circannual parts of photoperiodic system. Special attention is given to vegetative part of photoperiodic system and melatonin--"the hormone of dark". It is supposed that adenosine, one of the humoral elements of photoperiodic system, is involved in transfer of duration of the light part of photoperiod. Due to presented data we have come to the conclusion that septohippocampal system is one of the center for saving photoperiodic information.