Impact of cysteine proteinase inhibition in midgut fluid and oral secretion on fecundity and pollen consumption of western corn rootworm (Diabrotica virgifera virgifera)

Cysteine proteinases predominate in the midgut fluid (MF) and oral secretion (OS) of adult western corn rootworm (WCR) based on their mild acidic pH optima (pH 6.0), enhanced activities after treatment with thiol reducing agents, and inhibition by selective cysteine proteinase inhibitors (PIs). Four cysteine PIs including E-64, calpeptin, calpain inhibitor II, and leupeptin (also a serine PI) strongly inhibited azocaseinolytic activity in a dose-dependent manner in both the MF and OS. The most significant effect on adult female WCR of cysteine PI consumption with corn pollen was the reduction in fecundity, but female survival was not apparently affected. Mean fresh weights for all PI-fed females were also lower than control groups. All PI-fed groups [E-64, calpain inhibitor I (Cal I) and leupeptin] had a significantly lower daily egg production than respective corn pollen-fed controls. E-64 was more potent than leupeptin and Cal I on inhibiting fecundity, which correlates with their relative anti-proteinase potency in vitro. E-64, Cal I, and leupeptin at 1.5-2 nmol/beetle/day reduced fecundity down to 25-45% of control values. Reduced egg production by PI-fed beetles results from a combination of the direct inhibition of protein digestion and a post-ingestive negative feedback mechanism, which reduces food intake. The supplement of ten essential amino acids into the E-64-treated pollen enhanced up to 3.7-fold the number of eggs laid compared to the E-64-fed group without these amino acids, suggesting that egg production is dependent on the supply of essential amino acids from corn pollen proteolysis.     

Comparison of sample collection methods for the PCR detection of oral anaerobic pathogens

AIMS: To provide evidence that DNA-PCR diagnostics of oral pathogens based on standard sample collection by paper point insertion from the depth of the periodontal pocket can be replaced by a novel non-invasive collection method based on swab technique from the gingiva. METHODS AND RESULTS: In this study we compared the results from two collection methods performed in 35 patients with chronic adult periodontitis. Statistical analysis showed a highly significant association of diagnostic results between both collection techniques. CONCLUSIONS: The Pocket-out method represents a reliable alternative to the standard collection technique for PCR diagnosis of oral pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to its simplicity and non-invasiveness, the Pocket-out collection could be performed in any physician office, or even by the patient himself. With respect to the putative association between periodontal disease and various systemic illnesses, this method could be integrated with various screening programs of oral pathogens.     

Microstructural characteristics of thin biofilms through optical and scanning electron microscopy

The combination of a conventional optical microscope with a specially designed glass flow cell was used to visualize in situ biofilms formed on opaque thin biomaterials through a simple non-invasive way (optical microscopy of thin biofilms, OMTB). Comparisons of OMTB with scanning electron microscopy (SEM) images were made. Thin metallic dental biomaterials were used as substrata. They were immersed in a synthetic saliva and in a modified Mitis–Salivarius medium inoculated with a consortium of oral microorganisms. To study the effect of bacterial motility, Pseudomonas fluorescens cultures were also used. The processes which give rise to the formation of the biofilm were monitored through OMTB. Biofilm microstructures like pores, water channels, streamers and chains of Streptococci, attached to the surface or floating in the viscous interfacial environment, could be distinguished. Thickness and roughness of the biofilms formed on thin substrata could also be evaluated. Distortions introduced by pretreatments carried out to prepare biological materials for SEM observations could be detected by comparing OMTB and SEM images. SEM images (obtained at high magnification but ex situ, not in real time and with pretreatment of the samples) and OMTB images (obtained in situ, without pretreatments, in real time but at low magnification) in combination provided complementary information to study biofilm processes on thin substrata.     

Th2 polarization enhanced by oral administration of higher doses of antigen

Although oral administration of a soluble proteinantigen can induce various immune responses, theeffect of the dosage of oral antigen on thepredominance of Th2-type cytokine and antibodyresponses has not been well clarified yet. In thepresent study, we fed T cell receptor (TCR) transgenic(tg) mice various amounts of chicken ovalbumin (0.1,5, and 250 mg) and examined the resulting immuneresponses to this antigen. In these TCR tg mice, theresponses of antigen-specific T cells were greatlyamplified concomitantly with significantantigen-specific cytokine secretion. We found that ahigh dose (250 mg) of antigen significantlyupregulated the serum antigen-specific IgG1 and IgAantibody responses in mice later intraperitoneallyinjected with antigen plus adjuvant. The miceadministered the same oral dose but not immunizedshowed upregulation of Th2-type IL-4 and IL-5secretion and downregulation of Th1-type IL-2 andIFN-. This enhancement of Th2-type cytokineand antibody responses was more marked when largerdoses of antigen orally administered. These resultsdemonstrated that antigen feeding induces thedevelopment of T cells secreting Th2-type cytokines ina dose-dependent manner and that these T cells have ahelper function for the production of antibodies ofthe Th2-type isotypes. This experimental system shouldbe useful to screen foods and other substances thatcan modulate Th2-type responses relating to allergy.     

The cDNA sequences of three tetrins, the structural proteins of the Tetrahymena oral filaments, show that they are novel cytoskeletal proteins

The oral filaments of the ciliate Tetrahymena consist of the tetrins, insoluble polypeptides with molecular masses of around 85 kD. We characterised the tetrins of T. thermophila by two-dimensional gels and derived a large number of peptide sequences by in gel digestion. Using RT-PCR techniques and RACE-PCR, the complete cDNA sequences of tetrins A, B and C were established. Although tetrins differ strikingly in protein sequence they show a common structural principle. A N-terminal domain of 60 to 100 residues contains most of the proline residues of the tetrins and is probably globular. It is followed by a long alpha-helical domain of 620 to 640 residues which either lacks prolines or in tetrin A contains a single proline residue. Although this long domain has coiled coil forming ability, the individual heptad repeats are not extensive. Tetrins are novel cytoskeletal proteins unique to ciliates. Since the three tetrin sequences account for all 900 amino acid residues obtained by microsequencing of peptides, an additional major tetrin seems excluded. A minor component D is related to tetrin B by peptide sequences. The isoelectric variants, particularly obvious for tetrin A, most likely reflect post-translational modifications. These could arise by phosphorylation of serines and threonines in the proline rich N-terminal domain.     

Tumour biology of a breast cancer at least partly reflects the biology of the tissue/epithelial cell of origin at the time of initiation - a hypothesis

A hypothesis is presented suggesting that initiation of breast epithelial cell freezes the cell at least partly according to the development/differention of cell at the time of initiation. Tumour biology will mimic the physiology of normal cell development at the time of initiation and this is preserved at least partly onwards. Also preferentially, tumours will develop from the cell type that is proliferating at the time of initiation. This may explain the overrepresentation of different types of histology in breast cancer in relation to age of the woman. The development of each tumour may follow at least partly a distinct pathway of evolution.     

Success of dental implants in elderly people--a literature review

Implant-supported dentures seem particularly appropriate for the predicament of being elderly and becoming edentulous. The aim of this article was to review the literature on success of dental implants in elderly people. The results of two studies suggested that the treatment with implants can be considered safe and predictable for older as well as for younger patients. Three studies found no increased implant failure-rate in patients with a compromised medical status. Four studies revealed high success-rates of dental implants among groups of elderly people. Within the limitations of this review of the literature it can be concluded that old age does not seem to represent a factor of major prognostic significance in treatment with dental implants.     

Effect of Heliothis subflexa herbivory on fruit abscission by Physalis species: the roles of mechanical damage and chemical factors

1. Insect oral secretions are important for the induction of a number of plant responses, but the relative role of mechanical damage in the induction of these responses is often not well understood. Damage from the frugivore Heliothis subflexa, a specialist on Physalis species, causes herbivore‐induced fruit abscission. In this field study, we examined the separate and combined effects of mechanical damage and H. subflexa oral secretions on Physalis fruit abscission. 2. To determine the relative role of mechanical and chemical factors, the following treatments were administered to fruit: (1) three levels of mechanical damage, (2) natural herbivore damage by control larvae and by larvae surgically treated to inhibit saliva secretion, and (3) injection of H.subflexa oral secretions and a water control. Abscission of mechanically damaged fruit with and without the addition of oral secretions was also compared. 3. Mechanical damage was sufficient to cause fruit abscission, and the addition of oral secretions to mechanically damaged fruit did not cause an increase in fruit abscission. Normal caterpillars and those treated to inhibit saliva secretion caused similar abscission rates. 4. Though most studies examining the effects of insect oral secretions on induced plant responses find these chemical stimuli to be important or essential, the results of the present study showed that oral secretions are not necessary for fruit abscission. Future work is needed to determine the relative importance of mechanical damage in herbivore‐induced plant responses in other systems.