A computer program for evaluating the hydrodynamic parameters of a macromolecule in solution for any given value of its axial dimensions

A FORTRAN IV algorithm is given for determining the hydrodynamic parameters of a macromolecule in solution for any specified value of the two axial ratios ($\text{a}\text{b}$, $\text{b}\text{c}$) of the equivalent triaxial ellipsoid model of semi-axes a ≥ b ≥ c for its gross conformation.     

Mechanism of inactivation of a Fasciola proteolytic enzyme by peptide aldehydes and alkylating agents

A proteolytic enzyme of the liver fluke Fasciola sp. was purified as described previously by ammonium sulfate fractionation, gel filtration on Sephadex G-200 column and l-phenylalanine-agarose chromatography. Leupeptin, a peptide aldehyde of microbial origin, competitively inhibited the enzyme activity with respect to the substrate $\text{α-N-}\text{benzoyl-}\text{l}\text{-argininamide}$; the apparent K_i value for leupeptin is 45 000-fold less than the apparent K_m for the substrate. Incubation of the enzyme with leupeptin resulted in time-dependent inactivation of the globinolytic activity, with an inactivation constant (K_inact) of 0.4 μM giving the half-maximum inactivation velocity, and with a minimum inactivation half-time (T) of 2.7 min at infinite concentration of this compound. The inactivated enzyme was not reactivated by extensive dialysis. These results imply that leupeptin yields an affinity labelling of an active site of the enzyme. The activity of the Fasciola proteolytic enzyme was also inactivated by other peptide aldehydes and alkylating agents and inactivation constants observed were 0.5 μM for chymostatin, 13 μM for antipain, 2 μM for $\text{p-}\text{toluenesulfonyl-}\text{l}\text{-lysine}$ chloromethyl ketone, 140 μM for $\text{p-}\text{toluenesulfonyl-}\text{l}\text{-phenylalanine}$ chloromethyl ketone and 40 μM for iodoacetate under the conditions used.     

The immune response of Lacertaviridis to Leishmaniaagamae

$\text{Lacerta}$$\text{viridis}$ produced relatively heat-stable, dithiothreitol-sensitive, non-precipitating antibodies with β₂-electrophoretic mobility following exposure to $\text{Leishmania}$$\text{agamae}$ promastigotes but no histopathological or clinical signs of infection were seen. Significant four-and two-fold increases in the mean lysozyme and protein levels respectively were found in immune sera. Immunoenzyme techniques proved the most sensitive for detection of parasite antigens in selected body organs and immunoglobulins in sera.     

Antispermatogenic activity of 1-p-Chlorobenzyl-1H-indazol-3-carboxylic acid (AF 1312/TS) in rats. II. A study of treatments of duration between 5 and 180 days.

1-p Chlorobenzyl-1H-indazol-3-carboxylic acid or $\text{AF 1312}\text{TS}$ was given to rats in the diet for periods of time ranging from 5–180 days. Body weight, weight and histology of the main internal organs, food consumption, serum levels of the drug and blood composition were determined. The most extensive experiment was performed in young rats treated up to 180 days with a diet containing 0.5% AF $\text{1312}\text{TS}$. A marked and constant reduction in the weight of the testes with inhibition of spermatogenesis was observed during the entire experiment. In rats treated for 20–80 days a reduction in the weight of the ventral prostate, seminal vesicles and levator ani was also observed with a histological picture of hyposecretion of the above-mentioned glands: These effects were no longer detected following a 180-day treatment. The influence of doses and age on the effects of $\text{AF 1312}\text{TS}$ was also studied on the basis of a 30-day treatment period. In young rats, effects on spermatogenesis were not separated from effects on the accessory sex organs even with the lowest doses; in mature rats, instead, the spermatogenic process was specifically inhibited even with the highest doses. AF $\text{1312}\text{TS}$ was without effects in female rats. The toxicological tests gave no evidence of systemic toxicity of the drug.     

The specificity of the combining site of the lectin from Vicia villosa seeds which reacts with cytotoxic T-lymphoblasts

The combining site of purified Vicia villosa lectin was studied by quantitative precipitin and precipitin inhibition assays. The lectin, which specifically hemagglutinated blood group A erythrocytes nevertheless precipitated to different extents with blood group A₁, A₂, H, B and precursor I substances from saliva and ovarian cysts, and with different blood group substances of the same specificity indicating an interaction of the lectin with a non-blood group determinant site. The agglutinating and precipitating activities of the lectin were not strongly affected by EDTA or bivalent cations. Precipitates of Vicia villosa lectin with certain blood group glycoproteins showed unusually high solubilities as compared to other lectin glycoprotein and antigen-antibody precipitates. Inhibition assays with various monosaccharides, glycosides and oligosaccharides indicate that the Vicia villosa lectin is specific for terminal, non-reducing, α-linked dGalNAc. Of the monosaceharides tested, methyl αdGalNAc, p-NO₂-phenyl αdGalNAc and dGalNAc were best. They were about 100 times better inhibitors than the corresponding dGal compounds. The most potent inhibitor was methyl αdGalNAc which was 10 times more active than dGalNAc and 18 times more potent than the β-anomer. Among disaccharides tested, dGalNAcαl → 3dGal was most active, about as potent as methyl αdGalNAc, twice as active as dGalNAcαl → 6dGal and 8 times more potent than $\text{d}\text{GalNAc}\text{αl → 6}\text{d}\text{GalNAc}$, indicating the importance of a subterminal $\text{α}\text{l}\text{→ 3-}\text{linked}\text{d}\text{Gal}$ in the binding. $\text{d}\text{GalNAc}\text{α}\text{l}\text{→ 3}\text{d}\text{Gal}\text{β}\text{l}\text{→ 3}\text{d}\text{GlcNAc}$ was 7 times less active and the blood group A determinant

was less than $\text{1}\text{40}$ as active as $\text{d}\text{GalNAc}\text{α}\text{l}\text{→ 3}\text{d}\text{Gal}$. These findings indicate that the combining site of the Vicia villosa lectin is at least as large as the disaccharide $\text{d}\text{GalNAc}\text{α}\text{l}\text{→ 3}\text{d}\text{Gal}$ and that the αl → 3 linkage is important in the binding. The unique nature of this site is consistent with its high specificity for a glycoprotein on cytotoxic T-lymphocytes.     

Positive and negative regulation by the cII and cIII gene products of bacteriophage λ

Previous experiments have indicated that the cII and cIII gene products of bacteriophage λ serve to establish repression in an infected cell through a bifunctional regulatory activity: an activation of synthesis of cI protein (the maintenance repressor) and an inhibition of production of late lytic proteins. We have investigated further the relationship between the two regulatory activities of $\text{c}\text{II}\text{c}\text{III}$ by measurements of genetic and environmental influences on synthesis of endolysin and cI protein. A cy^? mutation which exhibits a cis dominant defect in positive regulation of the cI gene also is defective in negative regulation of endolysin. These data are consistent with a mechanism in which the cII and cIII proteins act at a single site in the y-region of λ DNA to provide for both positive and negative regulation. Multiplicity of infection exerts a strong influence on endolysin production, dependent on active cII and cIII genes; higher multiplicity favors repression. However, positive regulation of the cI gene is not substantially more effective at higher multiplicity. Thus there exists a capacity for discoordinate expression of the two regulatory activities of $\text{c}\text{II}\text{c}\text{III}$.     

The kinetics and thermodynamics of lysis of young and old sheep red blood cells

The kinetics of heat-induced lysis of a population of sheep red blood cells over the temperature range 42°–56°C are shown to be similar in form to the survivorship curves of multicellular organisms and are describable by the power law function, $\text{?(}\text{1}\text{N}\text{)(}\text{d}\text{N}\text{d}\text{t}\text{) = At(}{}^{\mathrm{n?1}}$. The A parameter of the power law function is examined in this model system in an attempt to show its relationship to molecular events. Arrhenius-type plots of the A parameter are different for old populations of red blood cells compared to young populations. The plot for the old cells shows a high energy transition at 50°C. For the young ceils an activation enthalpy of 132 kcal/mole is obtained with no transition occurring at 50°C. The parameter $\text{1}\text{τ}$, defined as $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>n</mtext>}}$ is more directly related to the molecular basis of the temperature dependence of the lysis kinetics. The Arrhenius plots of $\text{1}\text{τ}$ give activation enthalpies of 42.8 and 40.4 kcal/mole for young and old cells, respectively, and activation entropies of 57.6 and 50.3 cal/mole per degree. These activation enthalpies and activation entropies appear to be in accord with a compensation law for these qualities for protein denaturation, and support the suggestion that protein denaturation is the rate-limiting step in the lysis of sheep red blood cells.     

Antispermatogenic activity of 1-p-chlorobenzyl-1H-indazol-3-carboxylic acid (AF 1312/TS) in rats. I. Trials of single and short-term administrations with study of pharmacologic and toxicologic effects.

A new antispermtogenic agent is described. Following single or short-term administrations, 1-p-chlorobenzyl-1H-indazol-3-carboxylic acid, or $\text{AF 1312}\text{TS}$, produced in rats a long-lasting inhibition of the spermatogenic process. In adult rats the secondary sex organs were not affected, while in young rats some weight decrease of the prostate, seminal vesicles and levator ani was observed. The interstitial tissue of the testes as well as thymus, adrenals and hypophysis were not affected. $\text{AF 1312}\text{TS}$ proved to be devoid of the most common pharmacological activities.     

Studies of immunogenicity of Westphal lipopolysaccharides from Pasteurella multocida in mice.

The immunogenicity of Westphal lipopolysaccharides (LPS) from 2 strains of Pasteurella multocida was tested in mice. When lipopolysaccharide from P. multocida strain P-1234 (bovine source) was inoculated into CF1 or $\text{C}\text{3}\text{H}\text{HeJ}$ mice, less than 20 per cent of the mice survived homologous challenge infection 4 weeks later. However, 90 per cent, or more, of the CF1 or $\text{C}\text{3}\text{H}\text{HeJ}$ mice survived homologous challenge infection after immunization with formolized P-1234 bacteria. Sera from the CF1 mice, but not $\text{C3H}\text{HeJ}$ mice, formed precipitin lines against P-1234 LPS in an agar gel diffusion test.Hyperimmune sera from rabbits inoculated with formolized P-1234 bacteria passively protected more than 80 per cent of the CF1 mice against challenge infection; however, sera from rabbits inoculated with P-1234 LPS or LPS adsorbed to sheep red blood cells protected less than 20 per cent of the challenged mice.Absorption of rabbit anti-whole cell sera with LPS slightly reduced the capacity of serum to passively protect mice against challenge exposure.     

Inhibition of neuraminidase activity by derivatives of 2-deoxy-2,3-dehydro-N-acetylneuraminic acid

Eighteen derivatives of 2-deoxy-2,3-dehydro-N-acetylneuraminic acid were assayed for inhibitory activity against neuraminidases from viral and bacterial sources. Twelve of these compounds were active against neuraminidases of Vibrio cholerae, influenza $\text{A}\text{Mel}\text{,}\text{B}\text{Lee}$, and Newcastle disease virus, causing 50% enzyme inhibition in concentrations ranging from 10^?3M to 10^?6M. The most active of them and the most potent neuraminidase inhibitor described so far is 2-deoxy-2,3-dehydro-N-trifluoroacetylneuraminic acid. This compound has an inhibitor constant (K_i) of 7,9 × 10^?7, M for influenza $\text{A}\text{Mel}$ virus neuraminidase whereas the K_m of the virus enzyme for the substrate is 1000 times weaker (K_m = 6, 9 × 10^?4M). The mechanism of inhibition is competitive, and enzyme inhibition is independent of enzyme concentration. 2-Deoxy-2,3-dehydro-N-trifluoroacetylneuraminic acid inhibits hemagglutination by NDV and SV5 but does not inhibit agglutination of red cells by Sendai virus or influenza A and B viruses.     

Ribonucleic acid of barley yellow dwarf virus

Virions of the isolates of barley yellow dwarf virus transmitted by Macrosiphum avenae (MAV) and by Rhopalosiphum padi (RPV) contain a single component of single-stranded RNA of molecular weight 2.0 × 10⁶, estimated by sedimentation and gel electrophoretic mobility of formalinized RNA. The untreated ribonucleic acid of the RPV isolate appears to have a slightly more compact configuration than that of the MAV isolate, as shown by a slightly faster sedimentation coefficient (33.8 S vs 32.6 S) and a slightly faster migration rate in polyacrylamide gel electrophoresis. Virions of the MAV isolate had a $\text{280}\text{260}$ absorbance ratio of 0.52 and a $\text{230}\text{260}$ ratio of 0.82, whereas corresponding figures for RPV virions were 0.54 and 0.91. Both virions apparently have a high content of RNA.     

Endogenous murine leukemia virus-encoded proteins in radiation leukemias of BALB/c mice

To explore the role of endogenous retroviruses in radiation-induced leukemogenesis in the mouse, we have examined virus-encoded proteins in nine BALB/c leukemias by pulse-chase labeling procedures and serological typing with monospecific and monoclonal antibodies. The major gag precursor protein, Pr65^gag, was observed in all cases, but only three leukemias expressed detectable amounts of the glycosylated gag species, gP95^gag, or its precursor, Pr75^gag. No evidence was found for synthesis of gag-host fusion proteins. None of the leukemias released infectious xenotropic or dualtropic virus, but all nine expressed at least one env protein with xenotropic properties. In two instances a monoclonal antibody, $\text{35}\text{56}$, which is specific for the MuLV G_IX antigen, displayed a distinctive reactivity with this class of env protein, although this antibody is unreactive with replicating xenotropic viruses. An ecotropic/xenotropic recombinant env protein with the same $\text{35}\text{56}$ phenotype was observed in a leukemia induced by a strongly leukemogenic virus isolated from a BALB/c radiation leukemia.     

Ischemia-induced canine myocardial lysosome labilization: The role of endogenous prostaglandins and cyclic nucleotides

We tested the hypothesis that alterations in myocardial prostaglandin levels were associated with ischemia-induced lysosome labilization. To test this hypothesis, endogenous prostaglandin synthesis was restricted by administering indomethacin (INDO). After a thoracotomy in dogs, INDO (5 mg/kg) or vehicle was infused iv and 15 min later myocardial ischemia was induced by occlusion of the left anterior descending (LAD) coronary artery and the results compared to sham-operated animals. Myocardial tissue samples were biopsied 3 hr post-LAD ligation, homogenized, and the lysosome fraction subjected to a mild hypo-osmotic shock. The lysosomes from ischemic tissue were more labile compared to lysosomes from nonischemic tissue and this was associated with a decrease in myocardial $\text{cAMP}\text{cGMP}$ in ischemic tissue. Myocardial $\text{cAMP}\text{cGMP}$ correlated positively with myocardial lysosome stability (P < 0.05) and tissue prostaglandin E and A concentrations correlated negatively with myocardial cAMP (P < 0.05). In an in vitro liver lysosome system, INDO had no effect on enzyme release. These data suggest that ischemia-induced lysosome labilization via an increased prostaglandin release causes a lowered $\text{cAMP}\text{cGMP}$.     

Thyroid and thymus morphology in rats following sudden DRL reinforcement schedule changes

The possibility that sudden and maintained changes in an operant reinforcement schedule could induce discernable alterations in tissue morphology was explored. Numbers of thyroid follicles, thyroid (perifollicular) mast cells and thymus mast cells were counted from rats that had been adjusted to 80% free-feed weight and either shifted and maintained upon a DRL 12 sec schedule for 1 to 7 days after two weeks of DRL 6 sec training (DRL $\text{6}\text{12}$ sec group) or maintained on the DRL 6 sec condition (DRL 6 sec controls). Except for a marginal (p=0.06) decrease in thyroid mast cell numbers for the DRL $\text{6}\text{12}$ sec group, relative to the DRL 6 sec controls, these usually responsive morphological measures did not demonstrate statistically significant alterations.     

Antispermatogenic activity of 1-p. chlorobenzyl-1H indazol-3-carboxylic acid (AF 1312/TS) in rats. III. A light and electron microscopic study after single oral doses.

The modifications of the seminiferous epithelium at short time intervals after the administration of a single dose of 1-p. chlorobenzyl-1H-indazol-3-carboxylic acid, AF $\text{1312}\text{TS}$, have been sequentially studied in prepuberal and adult rats. $\text{AF 1312}\text{TS}$ is a new chemical compound with a selective antispermatogenic activity. Alterations of the seminiferous epithelium are observable within 24 hours after drug administration. The germ cells affected are primary and secondary spermatocytes and spermatids at various stages of their differentiation. Numerous nuclear and cytoplasmic aspects of the damage are illustrated. Early cytoplasmic and nuclear alterations are also observable in the Sertoli cells. The lesions of the germinal epithelium increase gradually and 5 days after the treatment numerous tubules show a conspicuous reduction of the germ cell number. Spermatogonia do not display cytologic alterations. The possibility is discussed that the Sertoli cells play a key role in the antispermatogenic action of $\text{AF 1312}\text{TS}$.     

Electron microscope heteroduplex study of sequence relations of T2, T4, and T6 bacteriophage DNAs

The regions of sequence homology and nonhomology between the DNA molecules of bacteriophages T2, T4, and T6 have been mapped by the electron microscope heteroduplex method. The heteroduplexes show characteristic reproducible patterns of substitution and deletion loops. The heteroduplex maps have been oriented with respect to the T4 genetic map by observing the positions of several T4 rII deletion loops and a lysozyme deletion loop relative to the heteroduplex patterns. All heteroduplexes show more than 85% homology. Some of the loop patterns in $\text{T}\text{2}\text{T}\text{4}$ heteroduplexes are similar to those in $\text{T}\text{4}\text{T}\text{6}$.We find that the rII, the lysozyme and ac genes, the D region, and gene 52 are homologous in T2, T4, and T6. Genes 43 and 47 are probably homologous between T2 and T4. The region of greatest homology is that bearing the late genes. The host range region, which comprises a part of gene 37 and all of gene 38, is heterologous in T2, T4, and T6. The remainder of gene 37 is partially homologous in the $\text{T}\text{2}\text{T}\text{4}$ heteroduplex (Beckendorf et al. 1972), but it is heterologous in $\text{T}\text{4}\text{T}\text{6}$ and in $\text{T}\text{2}\text{T}\text{6}$. Some of the tRNA genes are homologous, and some are not. The internal protein genes in general seem to be nonhomologous.Most of the regions of homology and nonhomology are gene size or larger. There is no evidence for many partially homologous sequences. This is the expected situation for phages which undergo genetic recombination.The molecular lengths of the T-even DNA's are the same within experimental error; the ratio of this molecular length to that of λ DNA is 3.63 ± 0.06, corresponding to a molecular length of 170 kilobase pairs (kb). This suggests that the molecular weight of the nonglucosylated T-even DNAs, carrying hydroxymethylcytosine, is 112 ± 4 × 10⁶ daltons.Circular duplexes with single-stranded tails are observed by denaturation and renaturation of any one of the T-even DNAs because of its circular permutation and terminal repetition. The observed lengths of the circular duplexes indicate that the genome sizes are 166 ± 2 kb (T4), 164 ± 2 kb (T6), and 160 ± 2 kb (T2). Thus, T2 has a smaller genome than T4 and T6. The mean lengths of the terminal repetitions are 3.3 ± 1 kb (T4 and T6) and 9 ± 2 kb (T2). These differences in length of the terminal repetitions are consistent with the observed differences in genome size. The variability in length of the terminal repetition in any one phage is consistent with the interpretation that there is a variability of about 1% of the full molecular length in the amount of DNA packaged by the head-full mechanism.     

Tryptophan-induced stimulation of hepatic ornithine decarboxylase activity in the rat

The effect of a single tube feeding of l-tryptophan on hepatic ornithine decarboxylase (ODC) activity in rats was investigated. The levels of ODC activity in the livers of control and experimental rats were assayed in vitro by measuring the release of ¹⁴CO₂ from DL-[1-¹⁴C]ornithine. Single tube feedings of varying levels of l-tryptophan ($\text{2.5–30 mg}\text{100 g}$ body wt) to overnight-fasted rats 1 hr before sacrifice exhibited increases in the hepatic ODC activities. l-Tryptophan ($\text{30 mg}\text{100 g}$ body wt) tube fed to overnight-fasted rats $\text{1}\text{6}$ to 12 hr before sacrifice induced hepatic ODC activities which were significantly elevated beginning at 1 hr and peaking at 2 hr (6.5-fold increase over controls). In vitro [¹⁴C]leucine incorporation into protein using hepatic microsomes of tryptophan-treated rats was significantly increased at 1 hr in comparison with that of controls. The tryptophan-induced stimulation of hepatic ODC activity was not affected by prior adrenalectomy but was abolished by pretreatment with cycloheximide. These studies demonstrate that a single feeding of l-tryptophan can significantly enhance in the rat the activity of ODC, a key enzyme in the biosynthesis of polyamines.     

Glucose preferences in wild and domestic guinea pigs

Male wild (Cavia aperea) and domestic (C. porcellus) guinea pigs were tested in two-bottle choice tests for preferences between glucose solutions of different concentrations and de-ionized water. Wild males showed significant preferences for concentrations between 0.025 and 0.4 M glucose while domestic males preferred only the 0.2 M glucose solution to de-ionized water. C. aperea males also consumed significantly greater volumes of liquid per kg body $\text{wt.}{}^{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}$ during the glucose tests than did the C. porcellus males. These comparative results contrast sharply with those obtained by other authors with wild and domestic Norway rats.