Hymenolepis nana: Immunogenicity of a lumen phase of the direct cycle and failure of autoinfection in BALBc mice

When $\text{BALB}\text{c}$ mice were given $\text{BALB}\text{c}$ mouse-derived cysticercoids (cysts) of Hymenolepis nana, only $\text{1}\text{43}$ mice became autoinfected, whereas most ($\text{31}\text{38}$) of dd mice given the same infection became massively autoinfected with mature worms. When $\text{BALB}\text{c}$ mice initially given cysts were challenged with eggs on Day 7, just before the patency of the primary infection, there was normal development into cysts, but almost none of them developed into adult worms. Thus, the failure of autoinfection of H. nana in $\text{BALB}\text{c}$ mice was not a result of failure of eggs to differentiate into cysts in the intestinal tissue, but a result of failure of these cysts to develop into adult worms in the lumen. The reasons why autoinfection does occur in dd and other strains of mice and not in the $\text{BALB}\text{c}$ strain are discussed in terms of the difference in onset of the late response in these strains of mice, ie., the response that is acquired after egg inoculation, and is directed against the lumen phase of cyst challenges. It is strongly suggested that (1) the lumen phase which follows cyst inoculation is highly immunogenic, but clearly differs from tissue phase which follows egg inoculation, (2) the autoinfection which occurs in some strains of mice is therefore not a result of no or poor immunogenicity of the lumen phase but is due to a delay of onset of the late response with the result that a secondary generation may mature, and (3) in other strains of mice, including $\text{BALB}\text{c}$, which acquire the late response within 15 days of initial egg inoculation, autoinfection normally does not occur after cyst infections.     

An endodextranase inhibitor from batch cultures of Streptococcus,mutans

An inhibitor of $\text{Streptococcus}$,$\text{mutans}$ endodextranase was detected in proteins prepared from batch cultures of $\text{S.}$,$\text{mutans}$ strains representing serotypes $\text{a}$ through $\text{g}$. Affinity chromatography of strain 6715-49 proteins, which apparently were free of endodextranase activity, yielded an active endodextranase and, in a separate peak, the endodextranase inhibitor. The presence of the inhibitor in culture fluids accounts for the absence of endodextranase activity in batch-grown cultures of $\text{S.}$,$\text{mutans}$ known to produce this enzyme.     

Coliphage T7 receptors are present in Pseudomonasaeruginosa rough lipopolysaccharides

Lipopolysaccharides (LPS) isolated from various rough derivatives of $\text{Pseudomonas}\text{aeruginosa}$ strains were found to neutralize coliphage T7. Concentrations of 0.4 – 17 μg LPS/ml were sufficient for 50% inactivation of T7 within 1 hour. From the LPS analyses of the mutants, it is believed that T7 may be binding to the heptose region of $\text{P.}\text{aeruginosa}$ LPS, suggesting a similarity in structure between the heptose regions of $\text{P.}\text{aeruginosa}$ and $\text{Escherichia}\text{coli}$ LPS.     

A soybean lectin having 4-O-Methyl-D-Glucuronic acid specificity

Evidence is presented for the presence of a new lectin activity in soybean seeds [$\text{Glycine}\text{max}$ (L.) Merrill] that has specificity towards the 4-O-methyl-$\text{D}$-glucurono-$\text{L}$-rhamnan exopolysaccharide produced by certain strains of $\text{Rhizobium}\text{japonicum}$. Bacterial agglutination and precipitin reactions revealed the lectin activity in phosphate-buffered saline extracts of seeds of all cultivars tested, including the “lectinless” varieties. Reaction of such extracts with carbohydrate haptens demonstrated that the specificity of the binding was towards 4-$\text{O}$-methyl-$\text{D}$-glucuronic acid, $\text{D}$-glucuronic acid and their methyl glycosides.     

Dipetalonema viteae: Microfilariae production in various mouse strains and in nude mice

Adult female Dipetalonema viteae worms obtained from hamsters were introduced beneath the dorsal skin of $\text{Balb}\text{c}$, $\text{C}{}_{57}\text{Bl}\text{6}$, and $\text{C}{}_3\text{H}\text{He}$ mice. The microfilaraemia from the transplanted worms in $\text{Balb}\text{c}$ mice was higher and persisted longer than in $\text{C}{}_{57}\text{Bl}\text{6}$, and in $\text{C}{}_3\text{H}\text{He}$ mice was intermediate between these two strains. The transplanted adult worms were killed earlier in $\text{C}{}_{57}\text{Bl}\text{6}$ compared to $\text{Balb}\text{c}$ mice; adult worms were killed before the microfilariae were cleared from the circulation. D. viteae infective larvae did not reach maturity in mice but when female worms were implanted into mice which had been infected with third-stage infective larvae 6 or 19 days previously, microfilarial production was inhibited. Outbred as well as inbred nude mice infected with 10 or 20 infective larvae died by Day 15, whereas the normal littermate control mice that received the same number of infective larvae remained alive and healthy. There was no difference in the duration and level of microfilaraemia from implanted female worms in outbred nudes and their heterozygous littermate control mice. In contrast, microfilaraemia in inbred $\text{Balb}\text{c}$ Nu+ was similar to that of inbred $\text{Balb}\text{c}\text{Nu}\text{Nu}$ only until Day 45; thereafter the microfilaraemia declined to zero around Day 160 in the Nu+, at which time it was still high and persisted longer in the $\text{Balb}\text{c}\text{Nu}\text{Nu}$. Transplanted adults were viable in inbred $\text{Balb}\text{c}\text{Nu}\text{Nu}$ for a longer time than in $\text{Balb}\text{c}$ Nu+. When infected, amicrofilaraemic nudes, littermate controls, and three strains of mice were challenged, a very low level short-lasting microfilaraemia resulted.     

Trichinella spiralis: Genetics of worm expulsion in inbred and F1 mice infected with different worm doses

The nematode Trichinella spiralis is rejected from the intestine at a time that is characteristic for each inbred strain of mouse. Previous work (R. G. Bell et al. 1982a) had empirically identified strong, intermediate, and weak phenotypes (NFR, $\text{C}\text{H}\text{He}$, and $\text{C57}\text{10}$ mice, respectively) in mice infected with 400 muscle larvae. It is shown that this classification applies to another eight inbred strains: SWR, $\text{DBA}\text{2}$, $\text{DBA}\text{1}$, LP, $\text{Bub}\text{Bn}$—all intermediate, and $\text{NZB}\text{BIN}$, C57L, A, and Mus molossinus—all weak. This phenotypic classification consistently applies with infections of 400–800 muscle larvae. Below doses of 300 muscle larvae, the strain designation of phenotype does not consistently apply. By this it is meant that the relative rejection rate changes for certain strains so that eventually some strains that were strong (NFR) or intermediate (AKR) responders to 400 muscle larvae become weak responders to 50 muscle larvae. Other strains increase their relative rejection time (B10 · BR, B10 · Q) while many do not change (NFS, $\text{C}\text{3}\text{Heb}\text{Fe}$, $\text{DBA}\text{2}$, $\text{DBA}\text{1}$). The phenomenon is most apparent in inbred parental strains rather than in F₁ crosses, and it represents a phenotypic variation in rejection time that is dependent on dose. It is also demonstrated that time of rejection is directly proportional to dose in all inbred and F₁ mouse strains that we have examined. Analysis of F₁ crosses shows that most have the rejection time of the strongest responding parental line, suggesting simple genetic control of strong, intermediate, and weak responses. Two F₁ crosses invalidated this theory. The $\text{DBA}\text{1}\text{×}\text{C3}\text{H}\text{He}$ (intermediate × intermediate) showed a strong response. The additive effects of parental rejection phenotype indicated that these lines could not be genetically identical for intermediate responsiveness. Similarly, the NFR (strong) × B10 · BR (weak) F₁ showed intermediate rejection, indicating partial dominance of $\text{C}\text{57}\text{B}\text{1}\text{10}$ genes over the strong responder NFR strain. Neither the primary expulsion time phenotype, phenotypic variation to low doses, or the rejection characteristics of F₁ crosses could be ascribed to genes linked to the major histocompatibility complex.     

Schistosoma mansoni: Splenic lymphocyte responses of mice after initial exposure to highly irradiated cercariae

Inbred $\text{C}\text{57}\text{B}\text{1}\text{6}$ and CBA mice were immunized with ⁶⁰Co-irradiated (50 kR) Schistosoma mansoni cercariae. Based on the percentage reduction from controls in the numbers of adult parasites developing from a challenge cercarial exposure, the level of protection among immunized $\text{C}\text{57}\text{B}\text{1}\text{6}$ mice ranged from 56 to 74%, and among immunized CBA mice from 10 to 27%. In a longitudinal study, parallel in vitro comparisons of mitogen- and antigen-stimulated lymphocyte proliferative responses were performed with spleen cells from immunized and control mice of both strains. In contrast to decreased mitogen reactivity during a chronic, patent infection, immunization with irradiated cercariae resulted in no alteration in PHA and LPS responses in the reactivity of either strain. A vigorous antigen-specific reactivity was noted in the responses of immunized CBA mice. Additionally, a biphasic pattern of responsiveness characterized the CBA responses to antigens of cercarial, adult worm, or schistosomal egg origin. In comparison, there was a greatly diminished reactivity in immunized $\text{C}\text{57}\text{B}\text{1}\text{6}$ mice to the same antigens. Therefore, no obvious correlation existed in this model between the relative magnitude of antigen-specific responses between the two strains and the level of anti-schistosome immunity induced.     

Identification and characterization of a new methylated amino acid in ribosomal protein L33 of Escherichiacoli

Methylated amino acids from ribosomal protein L33 of various $\text{Escherichia}\text{coli}$ strains (Q13, B and MRE600) were analyzed. It was found that while protein L33 from $\text{E.}\text{coli}$ Q13 contains two methylated neutral amino acids (peaks I and II), only one methylated neutral amino acid (peak I) was found in protein L33 derived from both $\text{E.}\text{coli}$ strains B and MRE600. The methylated amino acid present in peak I was identified as N-monomethylalanine by ion-exchange column chromatography, high-voltage paper electrophoresis and descending paper chromatography using different solvent systems. This marks the first time that N-monomethylalanine was found in any ribosomal protein.     

Trypanosoma vivax: Courses of infection with three stabilates in inbred mouse strains

The courses of infection in inbred mouse strains were compared following infection with three Stabilates of high, intermediate, and low virulence of Trypanosoma vivax stock Zaria Y486. Mouse strains could only be shown to differ in their resistance to T. vivax infections as judged by the height of the initial parasitemia and survival times when a trypanosome population of low or intermediate virulence was used. A T. vivax population of high virulence was uniformly lethal. Comparison of lytic antibody titers between groups of resistant ($\text{C}\text{57}\text{B}\text{1}\text{6}$) and susceptible ($\text{Balb}\text{c}$) mice did not show any significant differences in titers of the surviving mice but the mice in either group which did not control the initial parasitemia had lower lytic antibody titers than those which did. A significantly larger number of $\text{Balb}\text{c}$ mice failed to control the initial infection as compared to the $\text{C}\text{57}\text{B}\text{1}\text{6}$. Treatment with cyclophosphamide did not ablate differences in susceptibility between the two strains. The use of congenic mice showed that these differences in susceptibility were not related to differences in the major histocompatibility complex between these strains.     

Possible origin and function of the parasporal crystals in Bacillusthuringiensis

Acrystalliferous strains of $\text{Bacillus}\text{thuringiensis}$ subsp. $\text{kurstaki}$ were isolated at a high frequency following heat treatment of spores. Spores of these strains lacked a 130,000 dalton glycoprotein, the major component common to both parasporal crystals and coats and were nontoxic to tobacco hornworm larvae. Moreover, the deficiency of this glycoprotein resulted in lysozyme sensitivity of the spores of some mutants and the presence of new spore coat proteins in others. All nontoxic acrystalliferous mutants lacked the complete array of at least six plasmids present in the wild type, implying a relationship between presence of plasmid(s) and toxicity. The unique capacity of this species to alter the surface coating of spores which appears to be related to crystal formation may provide flexibility for germination and growth in diverse soil environments.     

Hymenolepis microstoma: Mouse strain differences in resistance to a challenge infection

Antibody responses and host resistance to the tapeworm, Hymenolepis microstoma, were investigated using $\text{AKR}\text{J}$ and $\text{C}\text{3}\text{HeB}\text{FeJ}$ strains of mice. AKR mice were significantly more resistant than controls to a secondary infection following exposure to a 3-, 21-, or 40-day primary infection. During a primary infection, intestinal anti-worm antibody responses measured by an enzyme-linked immunosorbent assay were elevated in the more resistant AKR strain, whereas serum antibody titers did not differ between the two strains. However, during a secondary infection, serum IgA titers were higher in AKR mice than C3H mice. Suppression of the serum IgA anti-worm response by oral administration of lipopolysaccharide also suppressed resistance to a secondary infection. Intraperitoneal immunization with worm antigen resulted in a minor degree of protection in AKR mice. This protection was associated with increased intestinal antibody titers compared to mice not demonstrating protection. These results suggest that the protective responses observed in AKR mice relative to C3H mice reflect differences in mucosal antibody responses to H. microstoma.     

Radioactive puromycin formation as an assay for the proportion of active ribosomes in mammalian cells: Correlation with polysome profiles under different physiological conditions

We have established optimal conditions for the $\text{in vitro}$ formation of peptidyl-{³H} puromycin by mammalian ribosomes. The growth conditions of cultured Ehrlich acites tumor cells were manipulated to produce changes in the polysome profiles. The correlation between polysome content and peptidyl-{³H} puromycin formation was linear and excellent when different cell densities were compared. The percentage of ribosomes actively engaged in protein synthesis, calculated from the number of ³H-peptide bonds formed, was similar in rapidly growing Ehrlich cells (47%) and in young rat gastrocnemius muscle (44%). Starvation resulted in a 50% reduction in the number of puromycin-reactive ribosomes in rat gastrocnemius.     

The effect of beta-naphthoflavone on rabbit liver protein synthesis, and on the induction of cytochrome P-450 LM4 mRNA

A single injection of β-naphthoflavone dispersed in corn oil causes significant changes in rabbit liver polysome and polysomal poly(A+)mRNA driven $\text{in vitro}$ protein synthesis. The changes occur between 6–18 hr and 30–36 hr after the injection. Our data indicate that the first effect is due to the β-naphthoflavone and the second effect is due to the oil vehicle. $\text{In vitro}$ translation of rabbit liver polysomes obtained from treated rabbits followed by specific immunoprecipition and gel electrophoresis, showed that maximal levels of translatable cytochrome P-450 LM₄ occurred 18–24 hr after β-naphthoflavone treatment.     

Leucine biosynthesis: effect of branched-chain amino acids and threonine on a-isopropylmalate synthase activity from aerobic and anaerobic microorganisms

$\text{a-}\text{Isopropylmalate}$ synthase activity was demonstrated in the Sephadex G 25 gel filtrated crude extracts of one yeast and 43 bacterial strains belonging to 14 families. The enzyme was inhibited by leucine from all strains Bacteroides fragilis, Clostridia and several phototropic bacteria. The enzyme was inhibited by leucine from all strains investigated. In crude extracts of 17 species (8 genera) the leucine-mediated inhibition could be relieved by the addition of valine or isoleucine , but not by the addition of threonine or alanine. The enzymes from 11 species (7 genera) were inhibited by 1 mM valine and isoleucine, whereas the enzyme activity from 5 bacteria (4genera) were not so affected. These results suggest that valine and isoleucine are specifically involved in the regulation of leucine biosynthesis in several bacteria. The affect of valine and isoleucine on the IPM-synthase activity from mycobacteria and Corynebacterium autotrophicum lends support to the reclassification of Mycobacterium flavum 301 to C. autotrophicum. The antagonism between 5′,5′,5′-trifluoroleucine and amino acids and $\text{a-}\text{ketoisovalerate}$ was $\text{a-}\text{isopropylmalate}$ synthase in the presence or abssence of leucine and the reversal of the 5′,5′,5′-trifluoroleucine-mediated growth inhibition by these amino acids.     

Expression of subregion and haplotype preference for H-2Kk restricted cytotoxic T-cell responses in vivo and at the level of the precursor frequencies

Several strains of mice bearing the H-2K^k allele were found to generate in vivo strong CTL responses against TNP-haptenated syngeneic cells, while several other strains of mice were found to generate comparably weak or no responses. C3H × DBA/2)F1 mice (H-2^k × H-2^d) and A/J mice with the recombinant haplotype $\text{H-2}{}^{\mathrm{<mtext>k</mtext><mtext>d</mtext>}}$ generated CTL responses in vivo that were completely restricted toward the H-2^k haplotype or the K end of the $\text{H-2}{}^{\mathrm{<mtext>k</mtext><mtext>d</mtext>}}$ haplotype, respectively. The CTL activity of C3H × DBA/2)F1 and A/J mice against haptenated H-2^k targets was found to be more than 25-fold higher than the CTL activity on H-2^d targets. The CTL responses in vitro under macroculture conditions showed, on the other hand, only a 3- to 6-fold higher cytotoxic activity against the haptenated H-2^k targets as compared with haptenated allogeneic or H-2^d targets; and limiting dilution experiments in microcultures revealed that the CTL precursor frequencies were only 2- to 3-fold smaller for TNP-haptenated H-2^d or haptenated allogeneic targets than for haptenated H-2^k target cells. This indicated that sufficient numbers of H-2^d-restricted and allorestricted CTL precursors were actually present in these strains, but did not develop detectable cytotoxic activity in vivo. The exceptional property of the H-2^k haplotype is, therefore, only partly determined by a difference in the CTL precursor frequencies, and to the larger extent determined at the level of the activation of the CTL response.     

Repair of deaminated cytosine residues of DNA: biological significance of the absence of uracil from DNA.

Uracil-DNA glycosylase of $\text{Bacillus}\text{subtilis}$ is involved in repair of deaminated cytosine residues of DNA. Survivals of SPO2 phage after treatment with bisulfite and weak alkali are considerably higher in wild type strains than in $\text{urg}$ mutants, which are deficient in the enzyme activity, whereas survivals of bisulfite/alkali-treated PBS1 phage in the two types of cells are essentially the same. The spontaneous mutation frequency of a $\text{urg}$ mutant is three fold higher than is that of a wild type strain.     

Energy-dependence of nitrate reductase induction in Candidautilis

The requirement of a suitable energy source during the induced synthesis of nitrate reductase in $\text{Candida}\text{utilis}$ was investigated. The levels of nitrate reductase induced were shown to be energy-dependent, and to vary in response to the type of carbon source provided. Glycerol, fructose, ethanol, glucose, and sucrose served as efficient energy sources. Growth rate of the yeast and the induced level of nitrate reductase were dependent on the ratio of carbon to nitrogen in the induction medium, and ratio of 2 being optimal. Induction of nitrate reductase was inhibited by uncouplers, 2,4-dinitrophenol (DNP), dicumarol and carbonyl cyanide $\text{p}$-trifluoromethoxy phenyl hydrazone (CCCP), and by cyanide and azide, indicating an absolute energy-dependency. The facilitation of induction of a high level of nitrate reductase by exogenously added ATP as sole source of energy confirmed the obligate requirement of ATP for the synthesis of nitrate reductase in $\text{Candida}$$\text{utilis}$.     

Two temporal phases for the control of histone gene activity in cleaving sea urchin embryos (S. purpuratus)

This report presents an analysis of histone gene expression in the cleaving embryo of the sea urchin, Strongylocentrotus purpuratus, with emphasis on whether the regulatory site(s) in the pathway of gene expression change as development proceeds. The analysis focuses on the equation, $\text{dP1}\text{dt}\text{= M·f·n·}\text{A}\text{t}$, where $\text{dP1}\text{dt}$ = the absolute rate of histone synthesis; M = the mole quantity of histone messenger RNA; f = the fraction of histone mRNA in polysomes; n = the polysome size; and $\text{A}\text{t}$ = the rate of elongation of nascent histone polypeptide chains. The embryo solves this rate equation differently at different times. Measurements were made (at 15°C) of absolute rates of histone synthesis ($\text{dP1}\text{dt}$). The rate of histone synthesis increases at least 48-fold during the first 6 hr after fertilization from less than 0.5 to 24 pg embryo^?1 hr^?1; in the period from 6 to 12 hr, this rate rises to 182 pg embryo^?1 hr^?1, an additional 7.7-fold rise, resulting in an overall increase of 370-fold between the 1-cell and 200-cell stage. The fraction of newly synthesized (zygotic) histone messenger RNA that partitions into polysomes (f^zygotic) has also been measured during the first 12 hr of development. This fraction increases from 0.2 in the 2-hr embryo to 0.8 in the 6-hr embryo (16-cell stage), increasing slowly thereafter to near unity by 12 hr. The size of histone-synthesizing polysomes (n) does not change substantially over the 12-hr interval, remaining constant at a weighted mean of 5 ribosomes per polysome (range 3 to 7). Utilizing the data on f^zygotic and $\text{dP1}\text{dt}$, the rate of elongation of nascent histone polypeptide chains ($\text{A}\text{t}$) during the first 6 hr of development was estimated; $\text{A}\text{t}$ remains constant at 1.11 codons per second. This calculated value is in fair agreement with a direct measurement of histone peptide elongation rate in the 12-hr embryo. It is proposed that histone gene expression in cleaving sea urchin embryos be divided into two phases, distinguished on the basis of their pivotal translational parameters: Phase I (0–6 hr), during which f is rate determining, and Phase II (6 hr on), during which M is the rate-determining parameter.     

Accelerated net efflux of 3-O-[14C]methylglucose in isolated fat cells

(1) A flow-tube apparatus suited for measurement of rapid efflux of sugars from adipocytes is described. (2) Due to heterogeneity of fat cell populations, a conventional analysis of the time-course of net efflux of $\text{3-O-}\text{methylglucose}$ based on the integrated rate equation can produce gross errors in estimates of kinetic parameters. (3) The half-saturation constant and maximum transport capacity for $\text{3-O-}\text{methylglucose}$ transport were found to be about 3-fold higher for net efflux than for equilibrium exchange flux, both in insulin-stimulated and non-stimulated adipocytes. This suggests asymmetric kinetic parameters for $\text{3-O-}\text{methylglucose}$ transport.