The presence of inhibitory RNA elements in the late 3'-untranslated region is a conserved property of human papillomaviruses

Here we have tested the inhibitory activity of the late untranslated region (UTR) of nine different human papillomavirus (HPV) types representing three different genera and six different species. These HPVs include both low-risk and high-risk types. We found that the late UTR of the various HPVs all displayed inhibitory activity, although they inhibited gene expression to various extent. The late UTR from the two distantly related HPV types 1 and 16, which are two different species that belong to different genera, each interacted with a 55 kDa protein. This protein cross-linked specifically to both HPV-1 and HPV-16 late UTR, although it bound more strongly to HPV-16 than to HPV-1, which correlated with the higher inhibitory activity of the HPV-16 late UTR. Mutagenesis experiments revealed that inactivation of two UGUUUGU motifs in the HPV-16 late UTR or two UAUUUAU motifs in the HPV-1 late UTR resulted in loss of binding of p55. In summary, these results demonstrate that the presence inhibitory elements encoding PuU(3-5)Pu-motifs in the HPV late UTR is a conserved property of different HPV types, species and genera, and suggest that these elements play an important role in the viral life cycle.     

Antigenicity of mouse interferons: two distinct molecular species common to interferons of various sources

Acid-stable mouse interferons produced by lymphocytes, macrophages, and leukemic cells were found to share common antigenicities with L cell interferon. By the use of two kinds of anti-L cell interferon globulins, anti-α and anti-β raised in rabbits against two molecular species of L cell interferon, “L-α” and “L-β,” it was ascertained that these interferons consist of two types (α- and β-type) antigenically distinct from each other as proved by neutralization tests for antiviral activity and by affinity chromatography on anti-interferon Sepharose columns. Relative proportions of the two types varied according to the cell source. These two antigenically distinct types of interferon also differed in their electrophoretic mobility and heat stability.     

Comparative study of the hemolytic activity of ortho- and paramyxoviruses

A comparative study of hemolytic activity of influenza type A, B, and C viruses, human parainfluenza type 3, and Sendai virus showed the pattern of pH-dependence and the nature of the curve to differ not only for different viruses under study but also for different erythrocyte species. Studies of virus-induced hemolysis of influenza C virus demonstrated that, depending on the erythrocyte species used, it had common properties both with influenza types A and B viruses and with paramyxoviruses.     

Characterization of antiviral activity of spotted souslik (Spermophilus suslicus) interferons

The antiviral activity of three types of spotted souslik interferons So IFN alpha, So IFN beta and So IFN gamma was studied. Fibroblasts of lungs (SL), kidneys (SK) of adult sousliks and skin fibroblasts of foetuses (SE) were equally sensitive to three types of souslik interferons. In contrast to So IFN beta and So IFN gamma, So IFN alpha, exhibited a high (100% of activity in homologous cells) cross species antiviral activity in mouse embryo fibroblasts (MEF) and a low (3% to 10% of the activity) in bovine embryo fibroblasts (BEF) and human embryo fibroblasts (HEF). The development kinetics of antiviral activity not only depended on the interferon type but also on the temperature of incubation. In comparison with So IFN gamma, So IFN alpha and So IFN beta activated earlier the maximal antiviral state. Low incubation temperature (26 degrees C) did not decrease but only delayed the antiviral activity of spotted souslik interferons. Mixed preparations of So IFN gamma with So IFN alpha or So IFN beta exhibited synergistic antiviral activity at physiological (37 degrees C) and low (26 degrees C) temperatures. The development of antiviral activity of So IFN beta as well that of Mu IFN alpha/beta was inhibited by plant lectins which reacted with the cell membrane compounds. All three types of souslik interferons were completely destroyed by trypsin and boiling at 100 degrees C for 1 min. and partially by SDS. Their sensitivity to shaking, beta-mercaptoethanol and mouse antisera against So IFN beta was different in relation to the interferon type.     

Genetic and phenotypic variations among F1 progenies of Arthroderma benhamiae.

The genotypes and phenotypes of 77 isolates derived from ascospores produced from two genetically different Arthroderma benhamiae were studied. Specifically, mitochondrial DNA (mtDNA) type, nuclear DNA (nDNA) type, mating type, colony texture, growth rate, urease activity, red pigmentation and hair perforation were examined. The nDNA types based on the restriction fragment length polymorphism (RFLP) in the internal transcribed spacer (ITS) region of ribosomal RNA (rRNA) genes and mating types were inherited from parents independently. mtDNA type was inherited from only one parent. All the phenotypes, except hair perforation and mating type, showed great variations. Those seemed not to be a conclusive factor for species identification. Additionally, these characteristics appeared in variable combinations suggesting that they are not interrelated. The intensity of red pigmentation varied even within a colony, implying that it is not a strain-specific characteristic. Hair perforation was observed in isolates of all but one atypical strain, and therefore could be one characteristic of this species.     

Binding of different ligands to IgM-Fc receptors of rat leucocytes.

The primary receptor ligand interaction between rat leucocyte membrane receptors for IgM and their ligands were examined. We found that the incubation time for optimal IgM binding is different on the two types of IgM-Fc receptor-bearing spleen cells and peritoneal macrophages. The investigation of cytophilic activity of polyclonal or monoclonal IgM proteins and their fragments from various species indicated the fine specificity of receptors. Finally, data are presented which suggest a multiple point co-operative binding between IgM-coated erythrocytes and IgM-Fc receptor-bearing cells.     

Quantitative analysis and partial characterization of cytotoxin production by Salmonella strains.

The pathogenesis of the wide-spectrum human disease caused by Salmonella species is poorly understood. Cytotoxin production by other enteric pathogens has been increasingly investigated recently, and data are accumulating regarding the role of cytotoxins in enteric infections and hemolytic uremic syndrome. We studied the cytotoxic activity of 131 Salmonella strains of the major serotypes, including 94 strains of Salmonella enteritidis, 12 strains of Salmonella typhi, and 25 strains of Salmonella choleraesuis. Cytotoxicity was quantitatively determined in sonic extracts by a [3H]thymidine-labeled HeLa cell assay. All Salmonella strains examined showed some degree of cytotoxic activity. The geometric means +/- standard deviations of the amounts of cytotoxin produced (50% cytotoxic dose per milligram of bacterial protein) were 27 +/- 2 for S. typhi, 65 +/- 2 for S. enteritidis, and 117 +/- 2 for S. choleraesuis. Analysis of variance showed that the differences in cytotoxin production by the three species were significant (P less than 0.001). No significant differences were found between stool isolates and invasive strains of the same species. Neutralization studies showed that the cytotoxins produced by all Salmonella strains were immunologically distinct from Shiga toxin and the closely related Shiga-like toxins produced by Escherichia coli. DNA hybridization studies with DNA probes for Shiga-like toxins of types I and II showed no hybridization. In each species the cytotoxin was heat labile and sensitive to trypsin treatment, which indicated that its active component was probably protein in nature. Upon ultrafiltration with Amicon membranes and gel filtration chromatography, cytotoxic activity was found in the molecular weight range of 56,000 to 78,000. Our findings indicate that salmonellae produce cytotoxin(s) that may play a role in the manifestations of the various species.     

Fine structural localization of glucose-6-phosphatase activity in the pancreatic islets of two amphibian species (Salamandra salamandra L. and Rana esculenta L.).

The ultrastructural distribution of glucose-6-phosphatase activity has been investigated in the salamander and frog pancreas. In the pancreas of salamander the enzyme was located in the A-cells, while in frog it occurred in all main types of islet cells B-, A-, and D-cells). As a rule, the reaction intensity was higher in the frog islet cells. No reaction was recorded in the exocrine pancreatic tissue of both species. The glucose-6-phosphatase activity was constantly detected in the lumen of rough endoplasmic reticulum and between the nuclear envelopes. Other enzyme localizations, observed especially in the A-cells of the salamander pancreas, were considered possible diffusion artifacts ro remnants of other phosphatase activity. The enzyme distribution in different types of islet cells, as well as its functional significance are discussed in relation to the findings of other authors.     

Effects of Habitat Light Intensity on Mammalian Eye Shape

Many aspects of mammalian visual anatomy vary with activity pattern, reflecting the divergent selective pressures imposed by low light and high light visual environments. However, ambient light intensity can also differ substantially between and within habitats due to differences in foliage density. We explored the effects of interhabitat and intrahabitat variation in light intensity on mammalian visual anatomy. Data on relative cornea size, activity pattern, and habitat type were collected from the literature for 209 terrestrial mammal species. In general, mammalian relative cornea size significantly varied by habitat type. In within‐order and across‐mammal analyses, diurnal and cathemeral mammals from forested habitats exhibited relatively larger corneas than species from more open habitats, reflecting an adaptation to increase visual sensitivity in forest species. However, in all analyses, we found no habitat‐type effect in nocturnal species, suggesting that nocturnal mammals may experience selection to maximize visual sensitivity across all habitats. We also examined whether vertical strata usage affected relative cornea size in anthropoid primates. In most analyses, species occupying lower levels of forests and woodlands did not exhibit relatively larger corneas than species utilizing higher levels. Thus, unlike differences in intensity between habitat types, differences in light intensity between vertical forest strata do not appear to exert a strong selective pressure on visual morphology. These results suggest that terrestrial mammal visual systems reflect specializations for habitat variation in light intensity, and that habitat type as well as activity pattern have influenced mammalian visual evolution. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus

Cotton rats (Sigmodon hispidus) were maintained from birth in constant LD 14:10 photoperiods and temperatures. Wheel running was diurnal for 6 of 13 juvenile rats and nocturnal for most others. Most diurnal rats eventually added nocturnal activity components. In constant darkness the activity rhythms of adult rats free-ran with a period of 23.2 +/- 0.3 h; in constant illumination the period was 24.7 +/- 0.1 h, in conformation to Aschoff's rule for nocturnal rodents. Some previously nocturnal adult rats eventually adopted stable diurnal activity cycles and other were successively nocturnal, diurnal for 6 mo, and then nocturnal again while maintained in the LD 14:10 photoperiod. The existence of multiple activity types, as well as the spontaneous inversions from nocturnal to diurnal status substantiate and extend field observations of this species. Seasonal inversions from nocturnal to diurnal activity, previously attributed to fluctuating environmental conditions, may also be subject to regulation by endogenous processes. It is suggested that spontaneous phase reversals in activity reflect changes in entrainment of circadian pacemakers by the light-dark cycle or altered relations between such pacemakers and the overt activity rhythm.     

Negative correlation between phospholipase and esterase activity produced by Fusarium isolates

Fusarium species have emerged as one of the more outstanding groups of clinically important filamentous fungi, causing localized and life-threatening invasive infections with high morbidity and mortality. The ability to produce different types of hydrolytic enzymes is thought to be an important virulence mechanism of fungal pathogens and could be associated with the environment of the microorganism. Here, we have measured the production of two distinct lipolytic enzymes, phospholipase and esterase, by sixteen Fusarium isolates recovered from the hospital environment, immunocompromised patients'' blood cultures, foot interdigital space scrapings from immunocompromised patients, and foot interdigital space scrapings from immunocompetent patients (4 isolates each). Fourteen of these 16 isolates were identified as Fusarium solani species complex (FSSC) and two were identified as F. oxysporum species complex (FOSC). Some relevant genus characteristics were visualized by light and electron microscopy such as curved and multicelled macroconidia with 3 or 4 septa, microconidia, phialides, and abundant chlamydospores. All Fusarium isolates were able to produce esterase and phospholipase under the experimental conditions. However, a negative correlation was observed between these two enzymes, indicating that a Fusarium isolate with high phospholipase activity has low esterase activity and vice versa. In addition, Fusarium isolated from clinical material produced more phospholipases, while environmental strains produced more esterases. These observations may be correlated with the different types of substrates that these fungi need to degrade during their nutrition processes.     

Stress affects salivary alpha-Amylase activity in bonobos

Salivary alpha-Amylase (sAA) is a starch digesting enzyme. In addition to its function in the context of nutrition, sAA has also turned out to be useful for monitoring sympathetic nervous system activity. Recent studies on humans have found a relationship between intra-individual changes in sAA activity and physical and psychological stress. In studies on primates and other vertebrates, non-invasive monitoring of short-term stress responses is usually based on measurements of cortisol levels, which are indicative of hypothalamic-pituitary-adrenal activity. The few studies that have used both cortisol levels and sAA activity indicate that these two markers may respond differently and independently to different types of stress such that variation in the degree of the activation of different stress response systems might reflect alternative coping mechanisms or individual traits. Here, we present the first data on intra- and inter-individual variation of sAA activity in captive bonobos and compare the results with information from other ape species and humans. Our results indicate that sAA activity in the bonobo samples was significantly lower than in the human samples but within the range of other great ape species. In addition, sAA activity was significantly higher in samples collected at times when subjects had been exposed to stressors (judged by changes in behavioral patterns and cortisol levels) than in samples collected at other times. Our results indicate that bonobos possess functioning sAA and, as in other species, sAA activity is influenced by autonomic nervous system activity. Monitoring sAA activity could therefore be a useful tool for evaluating stress in bonobos.     

Inhibitory effects of extracellular products from oral bacteria on human fibroblasts and stimulated lymphocytes.

Extracellular products of 12 strains of Streptococcus mutans and 5 additional species of oral bacteria were analyzed for their ability to inhibit proliferation of fibroblastoid cells (HeLa and AV3) and blast transformation of human peripheral blood lymphocytes obtained from normal individuals. Products from S. mutans strains AHT and BHT, Streptococcus intermedius, and Actinomyces viscosus inhibited [3H]thymidine uptake by fibroblastoid cells and phytohemagglutinin-stimulated lymphocytes. Products from S. mutans E49, Streptococcus salivarius, and Actinomyces naeslundii inhibited blast transformation of human lymphocytes but did not significantly inhibit the growth of fibroblastoid cells. Preparations from S. intermedius gave the greatest inhibitory activity against both target cell types; initial characterization of this preparation suggested a single factor active in both assays, in that the heat lability and Sephadex G-200 elution profile were similar for the inhibitory activity seen with the two cell types. The molecular weight of the inhibitor, estimated by gel filtration on Sephadex G-200 and Ultragel AcA34, was approximately 160,000. The results strongly suggest that oral bacteria produce heat-labile substances that interfere with fibroblast proliferation and alter the lymphocytic immunological response.     

Identification of RTX toxin target cell specificity domains by use of hybrid genes.

The Escherichia coli hemolysin (HlyA) and Pasteurella haemolytica leukotoxin (LktA) are cytolytic toxins encoded by genes belonging to the recently described RTX gene family. These cytotoxins are, respectively, 1,023 and 953 amino acids in length and are encoded by genes within identically organized operons. They share 45% amino acid sequence identities but differ in their target cell specificities. In vitro-derived recombinant hybrid genes between hlyA and lktA were constructed by using restriction endonuclease sites created by oligonucleotide site-directed mutagenesis. The cytolytic activity of hybrid proteins was investigated using as targets sheep erythrocytes and two cultured cell lines from different species (BL3, bovine leukemia-derived B lymphocytes; and Raji, human B-cell lymphoma cells). HlyA is cytolytic to all three cell types. LktA lyses only BL3 cells. Among the hybrid proteins displaying cytolytic activity, the striking finding is that the hemolytic activity of several LktA-HlyA hybrids was independent of any cytolytic activity against either cultured cell species. The hemolytic activity was associated with the HlyA region between amino acids 564 and 739. Structures that are critical for HlyA cytolytic activity against BL3 or Raji cells were destroyed when LktA-HlyA and HlyA-LktA hybrids were made, respectively, at amino acid positions 564 and 739 of HlyA. In contrast to HlyA, which lysed the two different cultured cell lines with equal efficiency, Lkt-HlyA hybrids possessing the amino-terminal 169 residues of LktA lysed BL3 cells more efficiently than Raji cells. This suggests that a significant but not exclusive element of the LktA ruminant cell specificity resides in the amino-terminal one-fifth of the protein. A molecular model of the functional domains of HlyA and LktA is presented.     

The use of sodium pentobarbital for the study of immobility-related (type 2) hippocampal theta

A series of experiments investigated the effects of sodium pentobarbital on the dentate electroencephalographic (EEG) activity of rats and rabbits implanted with tungsten microelectrodes. Type 1 (movement-related) theta was abolished in both species and Type 2 (immobility-related) theta was abolished in the rat but remained intact and readily elicitable by sensory stimulation in the rabbit, following anaesthetic doses of pentobarbital. It was proposed that sodium pentobarbital may be useful for the investigation of mechanisms underlying the two types of theta and that the effect of pentobarbital provides further evidence for species differences in the way the hippocampal formation produces Type 2 theta.     

Antimicrobial activity of two South African honeys produced from indigenous <Emphasis Type="Italic">Leucospermum cordifolium</Emphasis> and <Emphasis Type="Italic">Erica</Emphasis> species on selected micro-organisms

Background  

Honey has been shown to have wound healing properties which can be ascribed to its antimicrobial activity. The antimicrobial activity can be effective against a broad spectrum of bacterial species especially those of medical importance. It has also been shown that there is considerable variation in the antimicrobial potency of different types of honey, which is impossible to predict. With this in mind we tested the antimicrobial activity of honeys produced from plants grown in South Africa for their antibacterial properties on selected standard strains of oral micro-organisms.     

Metabolic characteristics of fibre types in human skeletal muscle.

Muscle biopsy samples were obtained from healthy subjects in order to evaluate quantitative differences in single fibres of substrate (glycogen and triglyceride) and ion concentrations (Na+ and K+) as well as enzyme activity levels (succinate-dehydrogenase, SDH; phosphofructokinase, PFK; 3-hydroxyacyl-CoA-dehydrogenase, HAD; myosin ATPase) between human skeletal muscle fibre types. After freeze drying of the muscle specimen fragments of single fibres were dissected out and stained for myofibrillar-ATPase with preincubations at pH's of 10.3, 4.6, 4.35. Type I ("red") and II A,B, and C ("white") fibres could then be identified. Glycogen content was the same in different fibres, whereas triglyceride content was highest in Type I fibres (2-3 X Type II). No significant differences were observed for Na+ and K+ between fibre types. The activity for the enzymes studied were quite different in the fibre types (SDH and HAD, Type I is approximately 1.5 X Type II; PFK Type I is approximately 0.5 X Type II, Myosin ATPase Type I is approxiamtely 0.4 X Type II). The subgroups of Type II fibres were distinguished by differences in both SDH and PFK activities (SDH, Type II C is greater than A is greater than B; PFK, Type II B is greater than A is approximately C). It is concluded that contractile and metabolic characteristics of human skeletal fibres are very similar to many other species. One difference, however, appears to be than no Type II fibres have an oxidative potential higher than Type I fibres.     

Production and properties of haemolysins from clinical isolates of the Proteeae

A collection of 198 clinical isolates of strains belonging to the tribe Proteeae was examined for haemolytic activity on blood agar and in Brain Heart Infusion Broth. The strains were of diverse bacteriocin and O-antigenic types and from a wide variety of sources. They included representatives of all species of Morganella, Proteus and Providencia. Approximately half of the M. morgani strains were haemolytic on blood agar. This activity was not associated with any particular bacteriocin type. The haemolysin was also produced during exponential growth in broth and was thermolabile and calcium dependent. All P. mirabilis strains and some P. vulgaris strains were non-haemolytic on blood agar. However, most strains of the Proteus spp., irrespective of their bacteriocin and antigenic type, produced, over a short period during exponential growth in broth, a heat-stable, cell-associated calcium-independent haemolysin. A smaller proportion of P. vulgaris and P. penneri strains produced, in addition, a thermolabile, calcium-dependent haemolysin which was associated with the formation of large haemolytic zones on blood agar. The relationship of these haemolysins to Escherichia coli haemolysin and their possible role in virulence is discussed. Haemolysin production was not found in any of the 74 strains of four species of Providencia.     

Receptive fields and trigger features of ganglion cells in the visual streak of the rabbit's retina

1. A survey of the properties of retinal ganglion cells in the central part of the rabbit retina has been carried out.2. The five types of unit previously encountered in the peripheral retina were also found in the central region. Their receptive fields were smaller, and tended to be oval-shaped with the long axis horizontal.3. In addition, three new types were discovered: orientation-selective cells, local-edge-detectors, uniformity-detectors.4. Orientation-selective cells were sensitive to either vertically or horizontally extended targets. Analysis suggested they were modified concentric units with an incomplete antagonistic surround.5. Local-edge-detectors responded to the appearance or movement of a contrasting border within the receptive field. They were inhibited by similar stimulation of the region surrounding the receptive field. Detailed attention was given to the demonstration of edge-detection.6. Uniformity detectors had a relatively high level of ongoing activity in the absence of stimulation. All forms of stimulation (lights flashed on or off, movement of darker or lighter targets) produced a diminution or cessation of ongoing activity.7. The results are compared with behaviour described in other species.