THE IONIC ACTIVITY OF GELATIN

2.5 and 1.25 per cent gelatin have been titrated potentiometrically in the absence of salts and in the presence of two concentrations (0.0750 and 0.0375µ) of NaCl, MgCl₂, K₂SO₄, and MgSO₄. The data have been used to calculate values of ± S = v^z – (v – 1)^z, where v^z = v ² – (v ² – v) r_x/18. The maximum and minimum values of S with NaCl were used to calculate the mean distance (r_x) between like charges in gelatin. This is found to be 18 Å.u. or over (between acid or basic groups) which agrees with the probable value and the titration index dispersion. Thus the data with NaCl are shown to be normal and to obey the equation found to hold for simple weak electrolytes; namely, pK'' – pK = Sa See PDF for Equation where S is related to the valence and distance by the above equations. Using the NaCl data as a standard the deviations (ΔS) produced by the other salts are calculated and are found to agree quantitatively with the deviations calculated from equations derived for the simple weak electrolytes. This shows that in gelatin, as in the simple electrolytes, the deviations are related to the "apparent valences" (values which are a function of the true valence and the distance between the groups). The maximum "apparent valences" of gelatin are 2.4 for acid groups (in alkaline solution) and 1.8 for basic groups (in acid solution). These values correspond to the hypothetical condition of zero distance between the groups. They have no physical significance but have a practical utility first as mentioned above, and second in that they may be used in the unmodified Debye-Hückel equation to give the maximum effect of gelatin on the ionic strength. The true effect is probably even lower than these values would indicate. The data indicate that gelatin is a weak polyvalent ampholyte having distant groups and that the molecule has an arborescent structure with interstices permeated by molecules of the solvent and other solutes. The size and shape probably vary with the pH.     

Identification procedure in a model of single fibre action potential – Part II: Global approach and experimental results

The present paper describes a global procedure for estimating all the synthesis parameters that generate a single fibre action potential (SFAP) in the Dimitrov–Dimitrova (D–D) convolutional model. We call this inverse problem Identification Procedure, and it is presented in two parts, this paper being the second. The procedure incorporates the candidate pair (CP) method developed in Part I, which provides the values of radial distance r and fibre diameter d of the simulated SFAP that best matches a potential under study. The CP-method required prior knowledge of all the excitation parameters. However, since the Identification Procedure makes no assumption about the excitation, multiple combinations of the synthesis parameters result in very similar SFAPs whose shape is close the signal under study. Analysis of the possible combinations reveals that r and d can be modelled as two jointly Gaussian random variables. The interest of the Identification Procedure is that, for a certain SFAP, it provides estimates of r and d, along with estimates of different parameters that determine the IAP waveform. Moreover, the procedure is able to determine the degree of error that accompanies the estimation of r and d.     

aug-MIA-QSAR modeling of antimicrobial activities and design of multi-target anilide derivatives

The antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli, as well as the antifungal activity against Aspergillus niger of a series of anilide derivatives have been modeled using augmented multivariate image analysis applied to quantitative structure–activity relationship (aug-MIA-QSAR). This QSAR approach is based on 2D molecular shape, as well as atomic sizes and colors to encode chemical, physical and biological properties. Predictive models with r² from 0.65 to 0.83 were used to estimate the antimicrobial activities of novel anilide analogs, which were built from the combination of substructures of the most active antimicrobial compounds along the series. Given the synergistic effect of different substituents to provide new molecules, promising compounds were proposed, highlighting a considerable multi-antimicrobial activity.     

A graphical analysis of life history evolution in biennial plants

Graphical analysis was done on the lfie history evolution of biennials (or monocarpic perennials). The age of seed production (x), the probability of surviving to agex [l(x)], and the number of seeds produced at agex[b(x)] determine the ultimate rate of population increase (r). The ages whenr=max andr=0 define the optimal and critical age for seed production, respectively, which depend on the shape and combination of thel(x) andb(x) curves. The otpimal age of seed production appears only for the convex function of the natural logarithm of the net reproductive rate [R ₀(x)], while the critical age appears irrespective of the shape of theR ₀(x) curves. The effects of environmental change on the optimal and critical ages are, analyzed, with the conclusion that in an environment imposing higher mortality or lower fecundity, delayed reproduction is favored. Age- and size-dependent productions of seeds have different effects on the variation ofr in a changing environment.     

Sequence interrelationships of the subunits of vicilin from pea seeds

Serological studies and comparison of N-terminal amino acid sequences with the amino acid sequence deduced from a cDNA clone have been used to establish the sequence relationships between the subunits of the pea seed storage protein, vicilin. Subunits smaller than M_r～50 000 (i.e., M_r 34 000, 30 000, 25 000, 18 000, 14 000, 13 000 and 12 000) show extensive homology with molecules within M_r～50 000 group. Both the sequencing and serological data confirm earlier evidence from studies on vicilin synthesisin vivo andin vitro which indicated that the vicilin subunits smaller than M_r～50 000 arose by endoproteolytic cleavage of parent molecules within the M_r～50 000 group. Cleavage in different M_r 50 000 parent molecules containing either one or both of two susceptible processing sites accounts for the formation of all the vicilin subunits smaller than M_r～50 000, with the possible exception of the M_r34 000 polypeptide. The position of these sites in the putative parents were defined by reference to a complete amino acid sequence deduced from the sequence of DNA complementary to mRNA for one member of the M_r～50 000 group.     

Similar clinical features among patients with severe adult growth hormone deficiency diagnosed with insulin tolerance test or arginine or glucagon stimulation tests

ObjectiveTo determine whether insulin tolerance tests (ITTs), arginine stimulation tests (ASTs), and glucagon stimulation tests (GST) identify patients who have similar clinical features of growth hormone (GH) deficiency when a diagnostic GH threshold of 3 μg/L is used.MethodsData were obtained from the KIMS database (Pfizer International Metabolic Database). Comparisons were made between patients who underwent ITT, AST, or GST for GH peak, body mass index, lipids, waist circumference, waist-to-hip ratio, and quality of life.ResultsA total of 5453 tests were available from 4867 patients registered in the database (ITT = 3111, AST To purchase reprints of this article, please visit: www.aace.com/reprints. Copyright © 2012 AACE = 1390, GST = 952). Significant (P < .001) intraindividual correlations were observed between the GH peaks for ITT vs AST (r = 0.655), ITT vs GST (r = 0.445), and AST vs GST (r = 0.632). GH peaks in response to all tests were negatively correlated to the number of additional pituitary hormone deficiencies and positively correlated to the insulinlike growth factor 1 standard deviation score. Body mass index had a negative influence on all 3 tests. Most clinical variables did not differ between the groups when comparing GH-deficient patients according to the diagnostic test used. The only exceptions that showed any difference were body mass index (slightly higher in the AST and GST groups), triglyceride levels (increased in the GST group), and insulinlike growth factor 1 (standard deviation score) (lower in the ITT and AST groups than in the GST group). Waist circumference was greater and quality of life was worse in the GST group than in the other groups.ConclusionsThe ITT, AST, and GST produce similar GH peaks, are influenced by similar clinical factors, and identify patients with similar features of GH deficiency at a diagnostic threshold of 3 μg/L. (Endocr Pract. 2012;18:325-334)     

Monitoring Prostate Tumor Growth in an Orthotopic Mouse Model Using Three-Dimensional Ultrasound Imaging Technique

Prostate cancer (CaP) is the most commonly diagnosed and the second leading cause of death from cancer in males in USA. Prostate orthotopic mouse model has been widely used to study human CaP in preclinical settings. Measurement of changes in tumor size obtained from noninvasive diagnostic images is a standard method for monitoring responses to anticancer modalities. This article reports for the first time the usage of a three-dimensional (3D) ultrasound system equipped with photoacoustic (PA) imaging in monitoring longitudinal prostate tumor growth in a PC-3 orthotopic NODSCID mouse model (n = 8). Two-dimensional and 3D modes of ultrasound show great ability in accurately depicting the size and shape of prostate tumors. PA function on two-dimensional and 3D images showed average oxygen saturation and average hemoglobin concentration of the tumor. Results showed a good fit in representative exponential tumor growth curves (n = 3; r² = 0.948, 0.955, and 0.953, respectively) and a good correlation of tumor volume measurements performed in vivo with autopsy (n = 8, r = 0.95, P < .001). The application of 3D ultrasound imaging proved to be a useful imaging modality in monitoring tumor growth in an orthotopic mouse model, with advantages such as high contrast, uncomplicated protocols, economical equipment, and nonharmfulness to animals. PA mode also enabled display of blood oxygenation surrounding the tumor and tumor vasculature and angiogenesis, making 3D ultrasound imaging an ideal tool for preclinical cancer research.     

Distribution and Significance of Fecal Indicator Organisms in the Upper Chesapeake Bay

Total viable aerobic, heterotrophic bacteria, total coliforms, fecal coliforms, and fecal streptococci were enumerated in samples collected at five stations located in the Upper Chesapeake Bay, December 1973 through December 1974. Significant levels of pollution indicator organisms were detected at all of the stations sampled. Highest counts were observed in samples collected at the confluence of the Susquehanna River and the Chesapeake Bay. The indicator organisms examined were observed to be quantitatively distributed independently of temperature and salinity. Counts were not found to be correlated with concentration of suspended sediment. However, significant proportions of both the total viable bacteria (53%) and fecal indicator organisms (>80%) were directly associated with suspended sediments. Correlation coefficients (r) for the indicator organisms examined in this study ranged from r = 0.80 to r = 0.99 for bottom water and suspended sediment, respectively. Prolonged survival of fecal streptococci in most of the sediment samples was observed, with concomitant reduction of the correlation coefficient from r = 0.99, fecal streptococci to total coliforms in water, to r = 0.01, fecal streptococci to fecal coliforms in sediments. The results of this study compared favorably with fecal coliforms: fecal streptococci ratios for the various sample types. Characterization of organisms beyond the confirmed most-probable-number procedure provided good correlation between bacterial indicator groups.     

Quantum-chemical and empirical calculations on Phospholipids VIII. The electrostatic potential from isolated molecules up to layer systems

Using 1-6-12 empirical functions with a solvent-averaged electrostatic contribution $\text{q}{}_{\mathrm{I}}\text{q}{}_{\mathrm{j}}\text{ε(r}{}_{\mathrm{Ij}}\text{)}\text{× r}{}_{\mathrm{Ij}}$ and electrostatic potentials from CNDO-type wavefunctions, the development of specific interactions of ions visualized by the molecular electrostatic potential of PO₄-group containing molecules was studied. Going from single molecules to monolayers made up of 37 head groups of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) for quantum-chemical calculations, or of 23 head groups for empirical calculations we found decreasing potential minima. Only the inclusion of the screening effect of water, simulated by a distance dependent dielectric constant, ε(r), gives an explanation of stereospecific interactions of model membranes with ions. This finding can be compared with results of simulation calculations on water structure above a PE head group layer.     

Anti-Tumoral Effect of the Mitochondrial Target Domain of Noxa Delivered by an Engineered Salmonella typhimurium

Bacterial cancer therapy relies on the fact that several bacterial species are capable of targeting tumor tissue and that bacteria can be genetically engineered to selectively deliver therapeutic proteins of interest to the targeted tumors. However, the challenge of bacterial cancer therapy is the release of the therapeutic proteins from the bacteria and entry of the proteins into tumor cells. This study employed an attenuated Salmonella typhimurium to selectively deliver the mitochondrial targeting domain of Noxa (MTD) as a potential therapeutic cargo protein, and examined its anti-cancer effect. To release MTD from the bacteria, a novel bacterial lysis system of phage origin was deployed. To facilitate the entry of MTD into the tumor cells, the MTD was fused to DS4.3, a novel cell-penetrating peptide (CPP) derived from a voltage-gated potassium channel (K_v2.1). The gene encoding DS4.3-MTD and the phage lysis genes were placed under the control of P_BAD, a promoter activated by L-arabinose. We demonstrated that DS4.3-MTD chimeric molecules expressed by the Salmonellae were anti-tumoral in cultured tumor cells and in mice with CT26 colon carcinoma.     

Organization of the Rudimentary Wing Locus in DROSOPHILA MELANOGASTER. I. the Isolation and Partial Characterization of Mutants Induced with Ethyl Methanesulfonate, Icr-170 and X Rays

New rudimentary (r) mutants have been isolated following mutagenesis with ethyl methanesulfonate (r^LE), ICR–170 (r^LI) and X rays (r^LX). From wing phenotype measurements on homoallelic females, it has been shown that the r^LE mutant series includes several leaky alleles, as well as alleles that produce moderate and strong r phenotypes. All of the tested r^LI alleles yielded strong r phenotypes in homoallelic females, whereas the r^LX series was found to include both moderate and strong alleles. Based on allele complementation for the wing phenotype, it was found that all three mutant series include both complementing and noncomplementing alleles, but the relative frequencies of these two types of alleles differ considerably among the three series. Complementing alleles comprise most of the r^LE mutant series (19 of 25) and almost one-half of the r^LX series (five of 12), while only one of 16 r^LI mutants is a complementing allele. Data from enzyme assays of mutants mostly support the direct correlation of genetic complementation units with the activities of the first three enzymes in the de novo pyrimidine biosynthetic pathway. All of these findings are discussed in light of evidence that these three enzymes are contained within a trienzyme complex in animals. We conclude that the available genetic evidence supports the contention that the trienzyme complex is encoded by a single mRNA.     

Steering by echolocation: a paradigm of ecological acoustics

1. Flights of three big brown bats (Eptesicus fuscus) landing on a hand and catching a suspended mealworm were video analysed.
2. Results were consistent with the bats using the same basic control procedure in the quite different approach tasks — namely keeping τ(r) = k _rand τ(a)τ(r) = k _αr. Here r is the current distance to the destination; α is the angle between the current direction of the destination and the goal direction of final approach (β _min); τ(r) = r/r, $\tau (\alpha ) = \alpha /\dot \alpha $ ; and k _r, k _αr are constants.
3. The bats were each quite consistent on a particular task (hand or mealworm) in the values they used for the control parameters k _r, k _αrand β _min. However, different values were used in the two tasks, which reflected the different behaviour required at the destination. Flights to hand required twisting and landing upside down and approach angle β _min was closer to vertical and k _rwas smaller and corresponded to decelerating nearly to a stop. In contrast, the mealworms were caught in mid flight and approach angle β _min was shallower and speed of approach was about constant.
4. τ(r) might be registered acoustically by τ(echo-delay) or by τ(echo-intensity). τ(α) might be registered by the bat's directional hearing and gravity sense.
5. The bats learned the tasks easily, suggesting that the control procedure they used in the experiments was part and parcel of the natural skills they had developed in the wild.

     

Intrinsic Birefringence of Multiple-Coiled DNA, Theory and Applications

The intrinsic birefringence of multiple-coiled DNA is computed in terms of an equally dense array of parallel DNA molecules. The birefringence for n times-coiled DNA molecules is given by [Formula: see text] where β_o = 0, β_i = tan^-1 (p_i/2πr_i), p_i = period of the i^th helix coil and r_i = radius of i^th helix coil. The formula is applied to two cases of helically coiled DNA in biological material and found to agree quantitatively with experimental results.     

A rapid quantitative method for the determination of thebaine in Papaver bracteatum

A rapid method enabling a quantitative analysis of thebaine in capsules and latex of Papaver bracteatum has been devised, based on a TLC technique. This method was compared to the commonly used GLC procedure, and highly significant correlation coefficient (r = 0.90) and linear regression were found between the two methods. Values for concentrations to the nearest ±0.25% of the standard spots can be reached by this simple and rapid thebaine determination.     

Erythrocyte lipid composition and sodium transport in human liver disease

In patients with liver disease there are usually increases in erythrocyte cholesterol and phosphatidylcholine concentrations. This increase in membrane lipid changes the shape of the erythrocyte and “spur” or “target” cells may be present. Sodium fluxes were measured in erythrocytes from 17 patients with a variety of liver diseases and from 17 normal subjects and the values related to the lipid content of the membrane. Ouabain-insensitive and ouabain-sensitive effluxes were lower in patients than in normal subjects and the reduction in ouabain-insensitive efflux was more marked. Sodium influx was also significantly lower in erythrocytes from patients than controls. Ouabain-sensitive and ouabain-insensitive effluxes and sodium influx did not correlate with the cholesterol content of erythrocytes from patients. Significant negative correlations were noted between ouabain-insensitive sodium efflux (r = ?0.63, P < 0.01), sodium influx (r = ?0.61, P < 0.01) and intracellular sodium concentration (r = ?0.66, P < 0.01) and the cholesterol : phospholipid molar ratio of the cell but there was no significant correlation between this ratio and the ouabain-sensitive sodium efflux (r = 0.41, P > 0.05). These results support the hypothesis that an altered lipid composition may affect the permeability of the erythrocyte membrane in patients with liver disease.     

Radioimmunoassay for quantitative determination of morphine in capsules of Papaver somniferum

A radioimmunoassay (RIA) procedure for the determination of pmol quantitites of morphine in capsule samples of Papaver somniferum was developed. An antiserum developed against a conjugate of morphine-3-hemisuccinate-BSA was relatively specific for morphine and possessed moderated cross-reactivity with codeine and mild cross-reactivity with thebaine, but none with narceine, papaverine, or noscapine. The standard curve was linear over a range of 0.01–0.20 ng. This assay allows for the rapid, sensitive and precise determination of morphine in unpurified aqueous extracts of capsule samples. The amounts of morphine in the aqueous extracts determined by radioimmunoassay were validated by high performance liquid chromatography (HPLC). The two methods show a high correlation coefficient (r = 0.98) with no significant difference in determinations of morphine content by RIA and HPLC.     

Biomass estimation on the basis of yeast cultivation model with morphophysiological parameters

An approach of biomass estimation of yeast fed-batch cultivation is proposed. It is based on the model that takes into account the information about the morphophysiological parameters: size, coefficients of shape and skewness of optical density of yeast cells. Procedure for parameter identification of the model, r ₁-rate of transformation of active cells into weakened cells, r ₂-rate of transformation of weakened cells into dead cells, r ₃-rate of transformation of weakened cells into active cells, r ₄-rate by which the buds of the budding cells grow and transform after their separation into active cells and r ₅-rate of transformation of active cells into budding cells, is described. The procedure is performed in MATLAB environment.     

A simple, rapid, and sensitive procedure for the estimation of RNA in erythroid cells on fritted glass filters

A simple, rapid, and sensitive procedure using fritted glass filters for the determination of RNA from erythroid cells is described. The RNA values obtained in determinations with this method are in good correlation to those from a conventional method (r = 0.981). Compared with the latter, the time requirements for the RNA estimation are reduced to less than 50%. The standard deviation from the mean in several estimations of different amounts of RNA in rabbit blood was about 10%.     

Reduced Ovarian Glyoxalase-I Activity by Dietary Glycotoxins and Androgen Excess: A Causative Link to Polycystic Ovarian Syndrome

Glyoxalase detoxification system composed of glyoxalase (GLO)-I and GLO-II is ubiquitously expressed and implicated in the protection against cellular damage because of cytotoxic metabolites such as advanced glycation end products (AGEs). Recently, ovarian tissue has emerged as a new target of excessive AGE deposition and has been associated with either a high AGE diet in experimental animals or hyperandrogenic disorders such as polycystic ovarian syndrome (PCOS) in humans. This study was designed to investigate the impact of dietary AGEs and androgens in rat ovarian GLO-I activity of normal nonandrogenized (NAN, group A, n = 18) and androgenized prepubertal (AN) rats (group B, n = 29). Both groups were further randomly assigned, either to a high-AGE (HA) or low-AGE (LA) diet for 3 months. The activity of ovarian GLO-I was significantly reduced in normal NAN animals fed an HA diet compared with an LA diet (p = 0.006). Furthermore, GLO-I activity was markedly reduced in AN animals compared with NAN (p ≤ 0.001) when fed with the corresponding diet type. In addition, ovarian GLO-I activity was positively correlated with the body weight gain (r_s = 0.533, p < 0.001), estradiol (r_s = 0.326, p = 0.033) and progesterone levels (r_s = 0.500, p < 0.001). A negative correlation was observed between GLO-I activity and AGE expression in the ovarian granulosa cell layer of all groups with marginal statistical significance (r_s = −0.263, p = 0.07). The present data demonstrate that ovarian GLO-I activity may be regulated by dietary composition and androgen levels. Modification of ovarian GLO-I activity, observed for the first time in this androgenized prepubertal rat model, may present a contributing factor to the reproductive dysfunction characterizing PCOS.