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Molecular crystals with water molecules in the crystal lattice (hydrates) can radically change properties if dehydrated. The two most practically relevant pathways of dehydration can be classified as either thermally-induced or solvent-induced. The solid form transformations occurring during these processes are taking place at the surface of the particles either in the solid–gas or solid–liquid interface. In this study, it is demonstrated how atomic force microscopy (AFM) can be used to measure topography, elastic modulus and work function to elucidate differences at the crystal surface depending on the dehydration pathway. These results are performed at a single particle level, so it would be important to link the findings to the bulk powder behaviour. To address this, static charging measurements for bulk powder samples were compared with the single crystal surface measurements. The thermally-induced anhydrate acquired more charge than the monohydrate at the bulk level which could be explained by the increase in work function and surface roughness at a single particle level. The change in sign for the solvent-induced anhydrate was also in agreement with the work function. This underpins the importance of also considering microscale properties, when characterizing nanoscale structures at the surface of particulate systems. [ABSTRACT FROM AUTHOR]

Surface charge density can be derived from atomic force microscopy (AFM) by using Derjaguin, Landau, Vervey and Overbeek (DLVO) theory. The sub-micrometer data allows observation of local differences in charge density and changes with time or solution composition, which has interesting applications in crystal growth and inhibition, bone formation and colloid behavior. To calibrate this type of AFM data and verify DLVO assumptions, it has to be correlated with an established technique. We successfully matched AFM derived surface charge densities with zeta potential measurements on a mica surface within one order of magnitude. A reproducible difference between surface charge of the mica substrate exposed to solutions cations with monovalent and divalent charge was also observed. The results provide confidence that the AFM method is valid for obtaining local surface charge information. [ABSTRACT FROM AUTHOR]

Calprotectin (S100A8/A9), a heterodimeric complex of calcium-binding proteins S100A8 and S100A9, is encoded by genes mapping to the chromosomal locus 1q21.3 of the epidermal differentiation complex. Whereas extracellular calprotectin shows proinflammatory and antimicrobial properties by signaling through RAGE and TLR4, intracytoplasmic S100A8/A9 appears to be important for cellular development, maintenance, and survival. S100A8/A9 is constitutively expressed in myeloid cells and the stratified mucosal epithelia lining the oropharyngeal and genitourinary mucosae. While upregulated in adenocarcinomas and other cancers, calprotectin mRNA and protein levels decline in head and neck squamous cell carcinoma (HNSCC). S100A8/A9 is also lost during head and neck preneoplasia (dysplasia). Calprotectin decrease does not correlate with the clinical stage (TNM) of HNSCC. When expressed in carcinoma cells, S100A8/A9 downregulates matrix metalloproteinase 2 expression and inhibits invasion and migration in vitro. S100A8/A9 regulates cell cycle progression and decelerates cancer cell proliferation by arresting at the G2/M checkpoint in a protein phosphatase 2α-dependent manner. In HNSCC, S100A8 and S100A9 coregulate with gene networks controlling cellular development and differentiation, cell-to-cell signaling, and cell morphology, while S100A8/A9 appears to downregulate expression of invasion- and tumorigenesis-associated genes. Indeed, tumor formation capacity is attenuated in S100A8/A9-expressing carcinoma cells in vivo. Hence, intracellular calprotectin appears to function as a tumor suppressor in head and neck carcinogenesis. When compared with S100A8/A9-low HNSCC based on analysis of TCGA, S100A8/A9-high HNSCC shows significant upregulation of apoptosis-related genes, including multiple caspases. Accordingly, S100A8/A9 facilitates DNA damage responses in HNSCC, promotes apoptotic cell death, and confers sensitivity to cisplatin and X-radiation in vitro. In the tumor milieu, loss of S100A8/A9 strongly associates with poor squamous differentiation and higher tumor grading, EGFR upregulation, increased DNA methylation, and, finally, poorer overall survival for patients with HNSCC. Hence, intracellular calprotectin shows a multifaceted protective role against the development of HNSCC. [ABSTRACT FROM AUTHOR]

The innate and adaptive immune systems are both crucial to oral disease mechanisms and their impact on systemic health status. Greater understanding of these interrelationships will yield opportunities to identify new therapeutic targets to modulate disease processes and/or increase host resistance to infectious or inflammatory insult. The topics addressed reflect the latest advances in our knowledge of the role of innate and adaptive immune systems and inflammatory mechanisms in infectious diseases affecting the oral cavity, including periodontitis and candidiasis. In addition, several potential links with systemic inflammatory conditions, such as cardiovascular disease, are explored. The findings elucidate some of the defense mechanisms utilized by host tissues, including the role of IL-17 in providing immunity to oral candidiasis, the antimicrobial defense of mucosal epithelial cells, and the pro-resolution effects of the natural inflammatory regulators, proresolvins and lipoxins. They also describe the role of immune cells in mediating pathologic bone resorption in periodontal disease. These insights highlight the potential for therapeutic benefit of immunomodulatory interventions that bolster or modulate host defense mechanisms in both oral and systemic disease. Among the promising new therapeutic approaches discussed here are epithelial cell gene therapy, passive immunization against immune cell targets, and the use of proresolvin agents. [ABSTRACT FROM AUTHOR]

The majority of HIV infections are initiated at mucosal sites. The oral mucosal tissue has been shown to be a potential route of entry in humans and primates. Whereas HIV RNA, proviral DNA, and infected cells are detected in the oral mucosa and saliva of infected individuals, it appears that the oral mucosa is not permissive for efficient HIV replication and therefore may differ in susceptibility to infection when compared to other mucosal sites. Since there is no definitive information regarding the fate of the HIV virion in mucosal epithelium, there is a pressing need to understand what occurs when the virus is in contact with this tissue, what mechanisms are in play to determine the outcome, and to what degree the mechanisms and outcomes differ between mucosal sites. Workshop 1B tackled 5 important questions to define current knowledge about epithelial cell-derived innate immune agents, commensal and endogenous pathogens, and epithelial cells and cells of the adaptive immune system and how they contribute to dissemination or resistance to HIV infection. Discovering factors that explain the differential susceptibility and resistance to HIV infection in mucosal sites will allow for the identification and development of novel protective strategies. [ABSTRACT FROM PUBLISHER]

The oral epithelium is the site of first exposure of HIV-1 to host tissues during oral sex with an infected partner or through breast-feeding by an infected mother. Although the oral epithelium is distinguishable by its apparent resistance, the mucosal surfaces represent a primary target of HIV-1. After oral exposure and swallowing, infection is detected prominently in the gastrointestinal tract, which becomes depleted of CD4+ T-cells. The oral cavity and palatine tonsils appear to resist infection and transfer to susceptible lymphoid cells in the lamina propria by local anti-HIV-1 mechanisms. In some cases, expression of these anti-viral mechanisms increases after exposure to HIV-1. During primary exposure and before seroconversion, based on limited in vitro and primate data, a window of opportunity for capture of HIV- 1 by the oral epithelium may exist. After seroconversion, the risk of infectious HIV-1 appearing in saliva is negligible. This report considers evidence that oral epithelium has the potential both to enable and to resist infection by HIV-1. [ABSTRACT FROM AUTHOR]

To show that an adsorbing biofilm carrier (GAC) can be advantageous for atrazine bioremediation over a non-adsorbing carrier, fluidized bed (FB) reactors were operated under atrazine limiting concentrations using Pseudomonas sp. strain ADP as the atrazine degrading bacteria. The following interrelated subjects were investigated: 1) atrazine adsorption to GAC under conditions of atrazine partial penetration in the biofilm, 2) differences in atrazine degradation rates and 3) stability of atrazine biodegradation under non-sterile anoxic conditions in the GAC reactor versus a reactor with a nonadsorbing biofilm carrier. Results from batch adsorption tests together with modeling best described the biofilm as patchy in nature with covered and non-biofilm covered areas. Under conditions of atrazine partial penetration in the biofilm, atrazine adsorption occurs in the non-covered areas and is consequently desorbed at the base of the biofilm substantially increasing the active biofilm surface area. The double flux of atrazine to the biofilm in the GAC reactor results in lower effluent atrazine concentrations as compared to a FB reactor with a non-adsorbing carrier. Moreover, under non-sterile denitrification conditions, atrazine degradation stability was found to be much higher (several months) using GAC as a biofilm carrier while non-adsorbing carrier reactors showed sharp deterioration within 30 days due to contamination of non-atrazine degrading bacteria. [ABSTRACT FROM AUTHOR]

The reticulocyte cell membrane was investigated for the role that it plays in cellular protein synthesis. It was found that a strong inhibition in protein synthesis occurred when a membranal extract was added to a cell-free protein-synthesizingsystem. The membranal extract was obtained by disrupting and then solubilizing cell membranes with the non-ionic detergent Triton X-100. The inhibition in protein synthesis could neither be attributed to an RNAse-type action nor to a reduction in the energy level of the system. Preliminary results show that the principal site of action occurs at the elongation or/and termination stages of protein synthesis. Initial purification of the inhibitory component was achieved. [ABSTRACT FROM AUTHOR]

Valinomycin was tritiated by exchange and its biological activity found to be similar to that of nonlabeled drug. [H]-valinomycin binds to red blood cell membranes following a biphasic pattern. High concentrations of the drug lead to an irreversible binding while low concentrations lead to a completely reversible binding. Maximum binding was obtained at acidic pH (pH 4.2) and physiological temperature (37°C). We demonstrate that valinomycin binds strongly to the lipidic phase of the membrane. When binding to erythrocytes and reticulocytes was compared, it was found that the mature red blood cells had less binding capacity than the reticulocytes. [ABSTRACT FROM AUTHOR]

Using [H]-Valinomycin we show here that two types of sites can be described for this cyclic depsipeptide. A first type is sensitive to low concentration of trypsin while the other, more internal, is uncovered by the use of the protease. Of these two kinds of sites, the more external one seems more concerned with the effect that Valinomycin has on protein synthesis in rabbit reticulocytes. However, when a high concentration of Valinomycin is used, all the sites can be occupied even those which can be revealed only by tripsinization. In this case, even prolonged trypsin action does not result in release of the protein synthesis inhibitory action of Valinomycin. It is concluded that hydrophobic sites are occupied by Valinomycin only after the cell surfae has been saturated by hydrophylic bonds with the antibiotic. [ABSTRACT FROM AUTHOR]

Infective endocarditis is characterized by the formation of septic masses of platelets on the surfaces of heart valves and is most commonly caused by viridans streptococci. Streptococcal virulence in endocarditis involves factors that promote infectivity and pathogenicity. Adhesins and exopolysaccharide (glycocalyx) contribute to infectivity. Although many factors may contribute to pathogenicity, the platelet aggregation-associated protein (PAAP) of Streptococcus sanguis contributes directly to the development of experimental endocarditis. PAAP is synthesized as a rhamnose-rich glycoprotein of 115 kDa and contains a collagen-like platelet-interactive domain, pro-gly-glu-gln-gly-pro-lys. Expressed on the cell wall of platelet aggregation-inducing strains (Agg+) of S. sanguis, PAAP apparently interacts with a signal-transducing receptor complex on platelets, which includes a novel 175-kDa α2-integrin-associated protein and a 65-kDa collagen-binding component. From available data, the role of PAAP in the pathogenesis of experimental endocarditis may be explained by a proposed mechanistic model. On injured heart valves, PAAP first enhances platelet accumulation into a fibrin-enmeshed thrombus (vegetation), within which S. sanguis colonizes. Colonizing bacteria must resist platelet microbicidal protein (PMPR). The aggregation of platelets on the heart valve may be potentiated by an ectoATPase expressed on the surface of the S. sanguis and platelet a-adrenoreceptors that respond to endogenous catecholamines. The expression of PAAP may be modified during infection. Collagen is exposed on damaged heart valves; fever (heat shock) occurs during endocarditis. In response to heat shock or collagen in vitro, PAAP expression is altered. After colonization, streptococcal exotoxin(s) may cause fever. Proteases and other enzymes from streptococci and host sources may directly destroy the heart valves. When PAAP is unexpressed or neutralized with specific antibodies, experimental endocarditis runs a milder course and vegetations are smaller. The data suggest strongly, therefore, that the role of PAAP may overlap the colonization function of putative adhesins such as FimA or SsaB. Finally, PAAP also contributes to the development of the characteristic septic mural thrombus (vegetation) of infective endocarditis and the signs of valvular pathology. [ABSTRACT FROM AUTHOR]

Comparative microbial functions in the plant root zone were studied by evaluating rhizosphere-derived Pseudomonas and Arthrobacter growth in chemostat culture and responses to root-exudate-related nutrients after varied starvation periods. These organisms were chosen to represent zymogenous and autochthonous microbes, respectively. In chemostat culture, the Pseudomonas isolate showed increased energy charge and decreased populations with higher growth rates, whereas the Arthrobacter had lower energy charge and cell population values which did not change appreciably with growth rate. The responses of these two types of organisms also differed with starvation. The Pseudomonas lost its ability to respire efficiently in the presence of several known root exudate components, whereas the Arthrobacter isolate, in comparison, maintained a lower but more consistent ability to utilize these nutrients with increased starvation. The Arthrobacter also showed increased utilization of several substrates after starvation, suggesting its potential ability to function under restricted nutrient availability conditions. These results suggest that Pseudomonas-type organisms in the rhizosphere may best function in periods of more intense exudate release, whereas organisms of the Arthrobacter- type may be more efficient at nutrient utilization during periods of lesser nutrient flux. Based on these data the rhizosphere-derived Pseudomonas isolate was considered to be an appropriate bacterium to use in more complex rhizosphere microcosm experiments where nutrient flux dynamics would be emphasized. [ABSTRACT FROM AUTHOR]

Certain strains of viridans streptococci bind platelets, which release ATP from dense granules and then aggregate. By hydrolyzing the released ATP to the platelet agonist, ADP, cell wall-associated ATPase activity of Streptococcus sanguis may amplify the aggregation of platelets. To identify and characterize this ecto-ATPase activity, whole cells were incubated with [14C]-ATP. The cell-free nucleotides were separated by thin-layer chromatography and quantified by liquid scintillation counting. Whole-cell activity showed temperature and pH optima in the physiological range. To isolate a soluble fraction with ATPase activity from the cell wall, whole cells were digested under osmotically stable conditions to produce protoplasts. Protoplasts and cells were separated from soluble cell wall materials by centrifugation. ATPase activity in cell fractions was identified by zymograms of native 8% polycrylamide gels after electrophoresis. The ecto-ATPase preparation, membrane and cytoplasmic ATPase in lysed protoplasts showed different zymograms and sensitivity to inhibition by DCCD, ouabain vanadate, azide and NEM. In electron micrographs of ultrathin sections of cells of S. sanguis, ATPase activity was localized to the cell wall. Since the pattern of localization to the wall changed with the phase of growth, the ecto-ATPase of S. sanguis may be associated with the development and maintenance of the cell wall. [ABSTRACT FROM AUTHOR]

A familial study of 13 Ashkenasy Jewish patients suffering from torsion dystonia (TD) of various origin, was carried out using clinical observation and determination of serum dopamine-beta-hydroxylase (DBH) activity. None of the following criteria: Jewish origin, dominant trait, slow progression and axial topography are specific for an elevated serum DBH activity. A significantly high serum DBH activity was found in TD patients and their relatives compared with controls, particularly in the childhood onset group. Intravenous injection of 20 mg Metoclopramide (MP) did not change serum DBH activity in 12 patients and 17 relatives. In one patient with symptomatic dystonia and two of her maternal relatives (from different fathers) serum DBH activity increased after i.v. injection of MP. In these three cases the serum DBH activity doubled and tripled. It is suggested that the MP induced elevation of serum DBH activity in relatives of TD patients indicates a genetic disposition. [ABSTRACT FROM AUTHOR]

During maturation of reticulocytes their ribosomes become less active for protein synthesis. Testing the stimulation effect of KCl ribosomal wash (KCl factors) extracted from ribosomes from cells oK different ages isolated by "density distribution of cells" technique, we show that active KCl factors are present on ribosomes from young cells and not on ribosomes from old cells. We demonstrate that the KCl factors can form polysomes from monosomes. The level of action of these factors is investigated and the possibility that they act as initiation factors is examined. [ABSTRACT FROM AUTHOR]

Purified IgM and IgG anti-Salmonella typhimurium 'O' antibodies were isolated at various intervals during the primary and secondary immune responses. Using agglutination, complement-dependent bactericidal effect and passive inhibition of antibody formation assays, the specific activities of IgM antibodies were found to be higher than IgG antibodies isolated at the same interval. As the immune response developed, a progressive increase in the specific secondary biological activities of both immunoglobulins was detected. In selected experiments, antibodies of a single immunoglobulin class were further fractionated into populations of molecules of different activity. An indirect assay of 'avidity' indicated that there was a direct relationship between this measure of antigen-antibody interaction and the secondary biological properties of these immunoglobulins. [ABSTRACT FROM AUTHOR]