Conductive and Kinetic Properties of Connexin45 Hemichannels Expressed in Transfected HeLa Cells

Human HeLa cells transfected with mouse connexin Cx45 were used to examine the conductive and kinetic properties of Cx45 hemichannels. The experiments were carried out on single cells using a voltage-clamp method. Lowering the [Ca²⁺]_o revealed an extra current. Its sensitivity to extracellular Ca²⁺ and gap junction channel blockers (18α-glycyrrhetinic acid, palmitoleic acid, heptanol), and its absence in non-transfected HeLa cells suggested that it is carried by Cx45 hemichannels. The conductive and kinetic properties of this current, I _hc, were determined adopting a biphasic pulse protocol. I _hc activated at positive V _m and deactivated partially at negative V _m. The analysis of the instantaneous I _hc yielded a linear function g _hc,inst = f(V _m) with a hint of a negative slope (g _hc,inst: instantaneous conductance). The analysis of the steady-state I _hc revealed a sigmoidal function g _hc,ss = f(V _m) best described with the Boltzmann equation: V _m,0 = −1.08 mV, g _hc,min = 0.08 (g _hc,ss: steady-state conductance; V _{m, 0}:V _m at which g _hc,ss is half-maximally activated; g _hc,min: minimal conductance; major charge carriers: K⁺ and Cl⁻). The g _hc was minimal at negative V _m and maximal at positive V _m. This suggests that Cx45 connexons integrated in gap junction channels are gating with negative voltage. I _hc deactivated exponentially with time, giving rise to single time constants, τ_d. The function τ_d = f(V _m) was exponential and increased with positive V _m (τ_d = 7.6 s at V _m = 0 mV). The activation of I _hc followed the sum of two exponentials giving rise to the time constants, τ_a1 and τ_a2. The function τ_a1 = f(V _m) and τ_a2 = f(V _m) were bell-shaped and yielded a maximum of ≅ 0.6 s at V _m ≅ −20 mV and ≅ 4.9 s at V _m ≅ 15 mV, respectively. Neither τ_a1 = f(V _m) nor τ_a2 = f(V _m) coincided with τ_d = f(V _m). These findings conflict with the notion that activation and deactivation follow a simple reversible reaction scheme governed by first-order voltage-dependent processes.     

Travelling wave phenomena in non-linear diffusion degenerate Nagumo equations

 In this paper we study the existence of one-dimensional travelling wave solutions u(x, t)=φ(x−ct) for the non-linear degenerate (at u=0) reaction-diffusion equation u _t =[D(u)u _x ] _x +g(u) where g is a generalisation of the Nagumo equation arising in nerve conduction theory, as well as describing the Allee effect. We use a dynamical systems approach to prove: 1. the global bifurcation of a heteroclinic cycle (two monotone stationary front solutions), for c=0, 2. The existence of a unique value c ^*>0 of c for which φ(x−c ^* t) is a travelling wave solution of sharp type and 3. A continuum of monotone and oscillatory fronts for c≠c ^*. We present some numerical simulations of the phase portrait in travelling wave coordinates and on the full partial differential equation. Received 15 December 1995; received in revised form 14 May 1996     

Growth characteristics of Uranoscopus scaber Linnaeus 1758, inhabiting the Iskenderun Bay (Northeastern Mediterranean)

This study aimed to determine the age and some growth characteristics of Atlantic stargazer (Uranoscopus scaber) from Iskenderun Bay (Northeastern Mediterranean). For this purpose, a total of 150 Atlantic stargazer ranging in size from 9.1 to 28.0 cm in total length (weight: 11.7–345.7 g) were collected as by-catch from a commercial trawl fishing boat at a depth of 80–100 m between May 2015 and January 2016. The bottom trawl gear used was equipped with a 44 mm stretched mesh size net at the cod-end. The percentage of females and males were 46.7% and 53.3% respectively. The total length–weight relationships equation with coefficient of determination (R²) were found as W = 0.011*TL^3.131, R² = .9728, for all individuals, W = 0.015*TL^3.021, R² = .9512 for females and W = 0.0102*TL^3.136, R² = .9553 for males. By using the von Bertalanffy equation, the growth parameters of Atlantic stargazer were estimated to be L_∞ = 42.35 cm, k = 0.098, t₀ = −1.8474 for all individuals; L_∞ = 36.92 cm, k = 0.138, t₀ = −1.2693 for females and L_∞ = 38.77 cm, k = 0.1, t₀ = −2.334 for males. In this study, age reading was done by two independent readers and index of average percentage error (IAPE) was calculated as 6.1%. The highest condition factor value calculated as 1.81 in the age group 6 and the lowest condition factor value was calculated as 1.48 in the age group 1.     

Number of adult female mites Varroa jacobsoni Oud. on hive debris from honey bee colonies artificially infested to monitor mite population increase (Mesostigmata: Varroidae)

Six honey bee colonies hived in Langstroth nuclei were each artificially infested with 100 phoretic Varroa mites. Hive debris on bottom inserts was inspected every 3–4 days. The adult Varroa mites were compared with mounted specimens and catalogued into lightly pigmented and darkly pigmented females. After 4 months, an acaricide treatment was used to estimate the final mite population. Based on light and dark adult counts, we propose a balancing equation that follows the Varroa population increase at 7 day intervals and allows the calculation of experimental population growth rates. The calculated Varroa finite rate of increase is =1.021. Exponential and logistic growth models fitted to the balancing equation data gave R ²=0.986 and R ²=0.991, respectively. To develop a more precise model it would be necessary to follow the population growth beyond our experimental data.     

Length–weight relationship and parameters of growth for the checkered puffer Sphoeroides testudineus from a karstic tropical coastal lagoon: La Carbonera,Yucatan, Mexico

This study reports length–weight relationships and growth parameters for Sphoeorides testudineus from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. A total of 461 specimens were collected between April 2009 and March 2010. The length–weight relationship was W = 0.061Lt^2.98. Model parameters of the von Bertalanffy growth equation were: L_∞ = 29.50 cm, k = 0.77 year^?1 and t₀ = ?0.168 years.     

Light/Dark Cycle and Temperature-Their Impact on Phosphate-Limited Growth of Oscillatoria redekei VAN GOOR in Semicontinuous Culture

Phosphate-limited growth of Oscillatoria redekei in semicontinuous culture has been studied under conditions of continuous illumination at 20 °C as well as in a 12/12 hours light-dark cycle at temperatures between 5 °C and 20 °C. The subsistence quota (q₀) amounted to 0.052 μmol mm⁻³ under all conditions, when the phosphate quota was expressed on the basis of cell volume. The interaction between temperature and phosphate quota and its impact on growth rate are described by the following model: Parameter values are t_opt=24.5 °C, t_min=0.95 °C, μ_max =0.873 d⁻¹. The maximum phosphate quota was found to depend on temperature and to increase along with declining temperature.     

Length–weight relationship,parameters of growth and mortality for the hardhead halfbeak Chriodorus atherinoides Goode & Bean, 1882 (Beloniformes: Hemiramphidae) from Yucatan Peninsula,Mexico

This study reports length–weight relationships and growth parameters for Chriodorus atherinoides from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. A total of 667 specimens were collected between April 2009 and March 2010. The length‐weight relationship obtained was W = 0.0034Lt^3.22. This study presents the first estimation of the model parameters of the von Bertalanffy growth equation (L_∞ = 27.30 cm, k = 0.76 year^?1 and t₀ = ?0.178 years), the instantaneous total mortality (2.51 year^?1) and the maximum length record (26.0 cm total length), which is greater than previously recorded.     

Estimating Arundo donax shoot biomass

We developed an equation for estimating Arundo donax shoot dry weight from shoot length. The equation, shoot dry weight (g) = 14.254 (standard error = ±0.275) × shoot height² (m), was as effective at explaining a high proportion of total variation in shoot dry weight (R² = 0.90) as more complicated equations containing additional morphometric parameters. Tested against two independent datasets, the equation provided accurate estimates of dry weight for shoots ranging from 0.3 to 7.06 m height (dataset 1, P < 0.0001, R² = 0.87, N = 29; dataset 2, P < 0.0001, R² = 0.82, N = 192). The equation provides aboveground biomass estimates from stem counts and heights more rapidly than harvest methods.     

Effects of different capture techniques on the physiological condition of bonefish Albula vulpes evaluated using field diagnostic tools

A study was conducted on bonefish Albula vulpes in The Bahamas to assess the utility of portable physiological diagnostic tools (i‐STAT analyser with E3+ ion and haematology cartridge, ACCU‐CHEK glucose meter and Lactate Pro lactate meter) for field physiology applications in remote locations. Physiological values derived from portable diagnostic tools were significantly related to values obtained from standard laboratory techniques [glucose (r²= 0·96), packed cell volume (PCV; r²= 0·33), Na⁺ (r²= 0·28), K⁺ (r²= 0·71) and Cl^? (r²= 0·15)]. Actual values (i.e. intercepts), however, tended to deviate slightly between the two techniques. Nonetheless, these tools showed promise for documenting relative differences among fishes experimentally exposed to treatments inducing different levels of ‘stress’. These tools were then used to characterize the effects of different capture techniques on the stress response of A. vulpes. Albula vulpes captured in seines and then temporarily held in pens were physiologically sampled between 1 and 45 min postcapture to evaluate postcapture stress dynamics. Blood glucose and lactate as well as PCV and haemoglobin (Hb) increased rapidly after capture but stabilized at maximal values by c. 20 min postcapture. When angled, larger A. vulpes took longer to exhaust and land than did smaller individuals. In addition, there was a positive relationship between the magnitude of increase in lactate and the duration of the angling event, implying that anglers can reduce stress by minimizing the duration of the fight. Fish sampled before and after a simulated angling treatment displayed clear increases in blood lactate, K⁺, PCV and Hb, providing some of the first data on how individual A. vulpes respond to angling stress. In summary, this study revealed that techniques are now available for conducting field physiological studies on A. vulpes and possibly other species in remote locales, and that haematological and biochemical indicators of physiological disturbance vary with the intensity of the angling event.     

Die Häufigkeit des Merkmales Lp(x) in der Berliner Bevölkerung

Zusammenfassung Mit einem absorbierten Pferdeimmunserum konnte ein neuer Lp-faktor — als Lp^x bezeichnet — nachgewiesen werden. Es wird an 1404 Serumproben klinisch gesunder Blutspender aus dem Raum Berlin die Genfrequenz für Lp^x ermittelt (positive Reaktion in 20,2%, errechnete Häufigkeit des steuernden Gens Lp ^x =0,1067).Mit dem Original-Anti-Lp (a) von Berg wurden bei 135 Humanseren der Lp (a)-Typermittelt: in 34,81% wurde eine positive Reaktion beobachtet (errechnete Häufigkeit des Gens Lp ^A =0,1926).

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A new Lp trait, Lp^x, was found using an anti-human immune serum from horse. The frequency in 1404 donors from the Berlin area was calculated. The frequency of the phenotype is 20,2%, the gene frequency 0,1067. Testing 135 sera with the original anti-Lp^a discovered by Berg we found 34,81% positive (gene frequency Lp^A=0,1926).

     

The complete rate equation,including the explicit dependence on Na+ ions,for the influx of α-aminoisobutyric acid into mouse brain slices

Summary The rate equation, including dependence on Na⁺-ion concentration for the influx of -aminoisobutyric acid into mouse brain slices incubated in isotonic glucose medium at 37°C, isv=0.402S/{1.02(1+788/[Na⁺]²)+S}+0.0477S, wherev=influx in mol/min, g final wet wt of slices; [Na⁺]=concentration of Na⁺ ions in medium, inmm; andS=concentration of -aminoisobutyric acid in medium, inmm. This equation shows two kinetically independent, parallel pathways of concentrative uptake: one, saturable and dependent on Na⁺; the other, unsaturable and independent of Na⁺. Influx is independent of ionic strength, Cl^– ionper se, and a moderate increase in tonicity. The binding of substrate to the saturable carrier depends on the Na⁺ concentration; the maximum capacity of this carrier does not. For transport, 2 Na⁺ ions must interact with each saturable transport site. This does not imply coupling between the flux of Na⁺ and the flux of -aminoisobutyric acid.     

Production of propionic acid by microbiological way. Part 1. Influence of the initial sugars and product concentrations

The best yields and productivities of 0.38 g · g^?1 and 0.35 g · l^?1 h^?1, respectively, for the propionic acid production in a batchsystem using sugar-cane final molasses as carbon source were obtained when an initial TRS concentration of 50 g · l^?1 was used. It was obvious that this process is severely inhibited by the acids produced and the most drastic effect (μ = 0) was at a TVA concentration near to 250 mmol · l^?1, independently of the initial TRS concentration employed. A generalizated equation of noncompetitive inhibition was adjusted: and kinetic inhibition constants for each initial TRS concentration studied were estimated.     

A generalized model of a resource-population system

Summary A system of nonlinear differential equations describing a resource-population system is analyzed in terms of the existence and characteristics of its equilibrium states.It is proved that, under the condition that k< (necessary condition for the population being able to grow under optimal conditions), it is a necessary and sufficient condition for the system to have a steady state that the resource input rate to the system be constant.When the resource input rate is a constant different from zero, the system has only one equilibrium point, at M ⁰=/⁰/k, A ⁰=–(/⁰/k)ln(1–k/), and this equilibrium point is always stable. In other words, the system population-resource will always reach the steady state, either monotonically (node) or by damped oscillations (focus), from any arbitrary initial condition in the positive quadrant.When the resource input rate is equal to zero, the system has an infinite number of equilibrium points at M ₀=0, A ₀=constant. All these equilibrium points are unstable in the sense that any slight increase in M will move the system away from the equilibrium states, except for the point M ₀=0, A ₀=0, which is the only stable equilibrium point, to which the system will tend. This stable equilibrium point corresponds to the condition of complete annihilation of both resource and population.Finally, it is proved that the system does not have limit cycles in the positive quadrant and is therefore incapable of self-oscillations.This work was partially supported by a Ford Foundation fellowship and various Cornell University fellowships.     

A New Functional Equation Analogous to CAUCHT-PEXIDER Functional Equation and its Application

The CAUCHY-PEXIDER functional equation H (x±y)=F(x) G(y) is generalized to the form H ((x^c±y^c)^1/c) = F(x) G(y), c≠0, assuming the function H(x) possesses a measurable majorant on a set of positive measure. The result is used to obtain a characterization of WEIBULL distribution. This functional equation is generalized to functions of vector variables.     

Life‐history traits of Aphanius danfordii (Boulenger, 1890) (Pisces: Cyprinodontidae), endemic to Kızılırmak Basin (Turkey)

The life‐history traits of Aphanius danfordii in Hirfanl? Reservoir were studied on the basis of 2252 specimens caught between April 2008 and April 2009. Maximum age was determined as five years for both sexes. The overall sex ratio of males to females was 1 : 1.21; however, this ratio varied by age and season. Mean total length at age data derived from scale readings were used to estimate growth. The von Bertalanffy growth parameters were: L_∞ = 126.63 mm, K = ?0.09, t₀ = 2.35 for females; and L_∞ = 61.2 mm, K = ?0.19, t₀ = 2.76 for males. The gonadosomatic index (GSI) values indicated spawning to be from May to September. Absolute fecundity varied from a minimum of 143 eggs for age one to a maximum of 698 eggs for age five. Relationships between fecundity–length and fecundity–weight were described by the equations: F = 0.0002 TL^3.3222 and F = 36.032 W^1.0053, respectively. The equation of the relation between absolute fecundity and age was F = 25.372 t^1.2343.     

Demythologizing environmentalism

Conclusion In the early 1950s Grant McConnell, Jr., called for a political adjudication of our environmental and political visions. He pointed out the arbitrary nature of Gifford Pinchot's noble-sounding formula (The greatest good for the greatest number over the longest time), noting that such a determination depended on whom you asked. No technocrat can determine the greatest good on the basis of some secret expertise or privileged knowledge. We need to resolve our disparate visions of the uses of nature and human beings politically, without recourse to privileged knowledge.But does such a political adjudication imply the unimpeded domination of the will of the majority? Not necessarily, because there is no overall majority for a total bundle of policies and programs — these must be horse-traded and haggled over on the basis of shifting coalitions. Yet, can it not be argued that even so, some very deeply held values of minorities will be trounced and trampled? It would be dishonest not to admit to such a danger. What we must do is try to define and develop a workable conception of baseline human rights that will be inviolable by the will of temporary majorities, and this itself is a tenuous political process which we have only just embarked on in recent times.The danger of Valentin Rasputins, Vernadskii cultists, and Deep Ecologists everywhere is that they are arguing from privileged knowledge. We know what is really best for you, what will cure you, they assert. They alone know the distinction between natural harmony and disorder, social health and corruption, pollution and purity, alienation and unity. They do not recognize the social construction of their ethical beliefs and political visions; they absolutize their individual truths. They may be right, but what if they are not...?It is therefore all the more important for those of us who wish to preserve a maximum of biotic and human diversity for our-selves and for future humans (and nonhumans) to be explicit about the moral and political agendas we embrace. The soundest way for us to prevail is to persuade our neighbors on this planet that our visions have something of value for them, too. We must keep in mind the fact that in a world where there exists more than one fanaticism, peaceful coexistence is in principle impossible.And if fanaticisms, including ecological ones, are the products of the fear or the fact of material, cultural, or spiritual dispossession, then we must work harder to make a world in which each of us and our interests are treated with equal respect. We cannot get there through the tainted means of absolutizing individual truths.Aldo Leopold, in his testament Sand County Almanac, as much as called for a new myth, for us to think like a mountain.⁵⁷ He called for a new myth because he believed that humans were dangerous (to ourselves, first of all, and to the planet), and that inculcating a myth was the only way to effect a deep behavioral change on a massive enough scale to save the situation.⁵⁸ It is my belief that myths are often more dangerous than the situations they seek to remedy. We need to cultivate a taste of de-mythologizing, of making our lives more self-aware. We need to become aware of our needs and our value preferences and to take responsibility for them as individual preferences. Then we will be in a good position indeed to respect and compromise with the preferences of our neighbors all around this planet, just as we would have them respect and compromise with ours. *** DIRECT SUPPORT *** A8402064 00005 *** DIRECT SUPPORT *** A8402064 00006 *** DIRECT SUPPORT *** A8402064 00007     

Parameter Estimation for the Bateman Function via Moments of the Empirical Curve

The parameters of the function f(t)=c(e^?at-e^?bt) are related in a simple way to the moments ^∞ tⁿf(t)^dt(n=0, 1, 2). Using empirical values of f, the moments can be estimated by numerical integration. Therefrom estimates of the parameters are obtained by elementary algebra.     

Correlation between antibodies to Cowdria ruminantium (Rickettsiales) in cattle and the distribution of Amblyomma vector ticks in Zimbabwe

Cowdriosis, caused by Cowdria ruminantium, is transmitted by Amblyomma ticks, which are widely distributed in Zimbabwe. To assess the distribution of this disease in Zimbabwe, cattle either exposed to Amblyomma ticks or maintained in areas free from these ticks were tested for antibodies to Cowdria. A total of 324 sera were tested using competitive ELISA and the indirect fluorescent antibody test (IFAT). At diptanks in Amblyomma-infested areas 52% (n=95) and 26% (n=47) of sera were positive by cELISA and IFAT, respectively. At diptanks in Amblyomma-free areas 11% (n=125) and 10% (n=134) of sera were positive by cELISA and IFAT, respectively. The results were significantly different between Amblyomma-infested and tick-free areas (²=24.73, P0.005 for IFAT and ²=57.53, P0.005 for cELISA). High background readings in field sera, possibly due to cross-reactive antibodies to Ehrlichia spp., complicated the determination of a realistic cut-off point, especially in cELISA. On the basis of the distribution of Amblyomma ticks, currently a large part of Zimbabwe can be considered endemic for the disease.     

An in vitro approach to study chromosomal DNA damage

In this study a simple electrophoresis approach has been proposed for assessing DNA damage per chromosome in vitro. Novel procedures of gel casting, sample loading, electrophoresis and quantification of damage have been suggested. Sets of Saccharomyces cerevisiae chromosomes subjected to DNA damage by Bleomycin, Co⁶⁰--radiation alone and in combination with Hoechst were studied in detail. Statistical analyses showed that damage induced by Bleomycin bore linear positive correlation with %GA (r=0.97) and %GT (r=0.61) contents of chromosomes. Samples pre-treated with Hoechst showed much less damage by Co⁶⁰--irradiation as compared to samples not treated with Hoechst but exposed to Co⁶⁰--irradiation. The `protective effect of Hoechst' bore linear positive correlation (r=0.8) with %TAT content of chromosomes.     

Antibody dynamics of 2009 influenza A (H1N1) virus in infected patients and vaccinated people in China

Background

To evaluate the risk of the recurrence and the efficiency of the vaccination, we followed-up antibody responses in patients with the 2009 pandemic H1N1 influenza and persons who received the pandemic H1N1 vaccine in Guangzhou China.

Methods

We collected serum samples from 129 patients and 86 vaccinated persons at day 0, 15, 30, 180 after the disease onset or the vaccination, respectively. Antibody titers in these serum samples were determined by haemagglutination inhibition (HI) assay using a local isolated virus strain A/Guangdong Liwan/SWL1538/2009(H1N1).

Results

HI antibody positive rate of the patients increased significantly from 0% to 60% at day 15 (χ² = 78, P<0.001) and 100% at day 30 (χ² = 23, P<0.001), but decreased significantly to 52% at day 180 (χ² = 38, P<0.001), while that of vaccinated subjects increased from 0% to 78% at day 15 (χ² = 110, P<0.001) and 81% at day 30 (χ² = 0.32, P = 0.57), but decreased significantly to 34% at day 180 (χ² = 39, P<0.001). Geometric mean titers (GMT) of HI antibodies in positive samples from the patients did not change significantly between day 15 and day 30 (T = 0.92, P = 0.36), but it decreased significantly from 80 at day 30 to 52 at day 180 (T = 4.5, P<0.001). GMT of vaccinated persons increased significantly from 100 at day 15 to 193 at day 30 (T = 4.5, P<0.001), but deceased significantly to 74 at day 180 (T = 5.1, P<0.001). Compared to the patients, the vaccinated subjects showed lower seroconversion rate (χ² = 11, P<0.001; χ² = 5.9, P = 0.015), but higher GMT (T = 6.0, P<0.001; T = 3.6, P = 0.001) at day 30 and day 180, respectively.

Conclusion

Vaccination of 2009 influenza A (H1N1) was effective. However, about half or more recovered patients and vaccinated persons might have lost sufficient immunity against the recurrence of the viral infection after half a year. Vaccination or re-vaccination may be necessary for prevention of the recurrence.