Biomedical subjects

F G Oppenheim

Publications and source records attributed to F G Oppenheim.

At least 55 records · Page 3Linked to original sources

PubMed1998

Salivary secretions: narcolepsy and central nervous system stimulants.

In an ongoing attempt to develop a model to study the influence of various diseases and drugs on saliva, we studied persons with narcolepsy treated with central nervous system stimulants. The aim was to study the secretion of salivary proteins in narcolepsy in the presence and absence of central nervous system stimulants. For this purpose, two proteins synthesized in acinar cells, acidic proline-rich proteins (PRPs) and statherin, were selected. Persons with narcolepsy treated with central nervous system stimulants only were included, n = 12, ages 14 to 68, seven females. Citric-acid-stimulated parotid and submandibular/sublingual saliva samples were collected from these persons during medication, after a drug-free period of one week, at least two weeks after the drug had been re-introduced, and from a matched healthy control group. PRP and statherin concentrations were determined by means of reversed-phase and anion exchange chromatography, respectively. Both concentration and output of statherins and PRPs were increased in persons with narcolepsy receiving central nervous system stimulants compared with healthy control individuals. When the drug was withdrawn, salivary flow rates were not influenced. In contrast, withdrawal of the drug led to a significantly decreased secretion of PRPs and statherin. The reduced protein secretion may reflect decreased adrenergic activation in narcolepsy, to be reversed by treatment with central nervous system stimulants. It can be concluded that measurements of both salivary fluid and salivary proteins may be necessary for an overall evaluation of the effects of a given drug or disease on salivary secretion.

Adolescent↗

PubMed1997

Molecular characterization of a major high molecular weight mucin from human sublingual gland.

Human submandibular/sublingual gland secretions contain a multimeric high molecular weight mucin (MG1) and a monomeric low molecular weight mucin (MG2). MG2 is the product of the MUC7 gene, whereas the gene for MG1 has not been identified. Previously, we isolated a clone (pSM2-1) from a human sublingual gland cDNA expression library using an antibody against deglycosylated MG1 (Troxler et al., Biochem. Biophys. Res Commun., 217, 1112-1119, 1995). In order to identify the mucin gene from which pPM2-1 was derived, Northern blots of human submandibular and sublingual gland RNA were hybridized with a series of probes for tandem repeats found in the high molecular weight secreted mucins MUC2, MUC3, MUC4, MUC5AC, MUC5B, and MUC6. The only known mucin expressed at high levels in sublingual gland was MUC5B, and no known mucin was expressed at high levels in submandibular gland. A series of overlapping clones was obtained by rescreening the sublingual gland cDNA library and by reverse transcriptase-polymerase chain reaction. The resulting clones connected pSM2-1 to a series of MUC5B tandem repeats at the 3' end of the repeat domain and provided the complete nucleotide and deduced amino sequence of the carboxyl terminal region of MG1. This region is enriched with respect to cysteine (approximately 10 mol %) and contained a D domain and a carboxyl terminal domain that could be aligned with the corresponding domains in human intestinal MUC2, human tracheobronchial MUC5AC, and human von Willebrand factor. The limited expression of known mucin genes, together with the considerable mucin synthesizing capacity of submandibular gland, suggests that a novel (previously not described) mucin gene is expressed in this gland and constitutes a portion of MG1 in salivary secretions.

Amino Acid Sequence↗

PubMed1997

Inhibition of experimental gingivitis in beagle dogs with topical salivary histatins.

Histatins, histidine-rich proteins found within parotid and submandibular secretions, are a novel class of endogenous peptides with antimicrobial properties. This masked, randomized, placebo-controlled preclinical investigation examined the effect of 3 topical histatins on the development of plaque and gingivitis in beagle dogs. 16, female, 1-year-old beagles were brought to optimal gingival health by mechanical scaling and polishing followed by rigorous daily tooth brushing. At the conclusion of this pretreatment period, dogs were randomly divided into 4 groups for the application of test formulations, and were placed on a plaque-promoting diet. Test agents included 3 synthetic salivary histatins (histatin 5, P-113 and P-113D) which were incorporated in hydroxypropyl methylcellulose gel at a concentration of 0.125%, and a placebo, or negative control, which was the gel vehicle alone. Throughout the 10-week treatment period, test formulations (2.0 ml) were applied 2 x daily to all premolar teeth using a Monojet syringe. Plaque formation and gingival inflammation were assessed using the plaque (PI) and gingival (GI) indices on days 0, 7, 14, 21, 28, 42, 56 and 70. Furthermore, bleeding to probing was recorded as a percent of sites (%BOP) and according to the modified sulcus bleeding index (mSBI). Comparisons among groups and between group pairs (active versus placebo) were made with Kruskal-Wallis tests with the average of data over the interval, days 14-42, being the primary focus of the analysis. From baseline to day 7, all groups expressed similar indices. Thereafter, overall significant differences among the groups were noted at day 42 for PI, at days 21, 28, 42 and 70 for GI, and at days 14 and 28 for %BOP (p < 0.05). In particular, beagles treated with P-113 demonstrated significantly lower PI scores at day 42 (p < 0.05), significantly lower GI scores from days 21 through 42 (p < 0.05), and significantly lower %BOP scores at days 14 and 28 (p < 0.05) compared to beagles treated with placebo. Beagles treated with P-113D exhibited significantly lower GI at day 42 compared to the placebo (p < 0.05). For the primary analysis conducted over the midtreatment interval (days 14-42), significant differences were detected for all parameters except mSBI (p < 0.05). Accordingly, significantly lower PI scores were found for P-113, lower GI scores for P-113 and P-113D, and lower %BOP for P-113 and P-113D compared to placebo (p < 0.05). These data indicate that in the beagle model, salivary histatins, P-113 and P-113D, topically applied, can significantly reduce clinical signs of plaque formation and gingival inflammation.

Administration, Topical↗

PubMed1997

Human salivary mucin MG1 selectively forms heterotypic complexes with amylase, proline-rich proteins, statherin, and histatins.

Heterotypic complexes between the high-molecular-weight mucin MG1 and other salivary proteins in human submandibular/sublingual secretion (HSMSL) could have a significant impact on the biological properties of these proteins in oral fluids in both health and disease. We describe a mild procedure for isolation and purification of native MG1 by gel filtration chromatography on Sepharose CL-2B which does not involve dialysis, lyophilization, use of denaturing agents, or covalent modification. Western blots of native MG1 probed with antibodies against 8 different salivary proteins showed that complexing occurs between MG1 and salivary amylase, proline-rich proteins (PRPs), statherins, and histatins but not MG1, sIgA, secretory component, or cystatins. When native MG1 was placed in 4 M guanidine hydrochloride and chromatographed on Sepharose CL-4B, ELISA measurement of column fractions showed that amylase, PRPs, statherins, and histatins were released. Interestingly, gel filtration resolved the material which eluted into 4 or 5 distinct peaks, suggesting that the released entities were heterotypic complexes. From these studies, the occurrence of at least three different types of complexes between MG1 and other salivary proteins has been identified. Type 1 complexes are dissociated by SDS-PAGE and in 4 M guanidine hydrochloride. Type II complexes are not dissociated under these conditions. Type III complexes are dissociated during SDS-PAGE and by 4 M guanidine hydrochloride, but the released proteins appear to be complexes containing amylase, PRPs, statherins, and histatins. The possible functional role of heterotypic complexes between MG1 and other salivary proteins as a physiologic delivery system, a mechanism for protection against proteolysis, a repository for precursors of the acquired enamel pellicle, and a vehicle for modulation of the viscoelastic and rheological properties of saliva is discussed.

Amino Acids↗

PubMed1996

Transfer of a gene encoding the anticandidal protein histatin 3 to salivary glands.

Mucosal candidiasis, the most common opportunistic fungal infection in human immunodeficiency virus (HIV)-infected patients, is an early sign of clinically overt acquired immunodeficiency syndrome (AIDS) and an important cause of morbidity, particularly in HIV-infected children. The appearance of azole-resistant strains of Candida albicans had made clinical management of candidiasis increasingly difficult. We propose a novel approach to the management of candidal infections that involves the use of naturally occurring antifungal proteins, such as the histatins. Histatins are a family of small proteins that are secreted in human saliva. We have constructed recombinant adenovirus vectors that contain the histatin 3 cDNA. These vectors are capable of directing the expression of histatin 3 in the saliva of rats at up to 1,045 micrograms/ml, well above the levels found in normal human saliva. The adenovirus-directed histatin demonstrated a 90% candidacidal effect in the timed-kill assay against both fluconazole-susceptible and fluconazole-resistant strains of C. albicans and inhibited germination by 45% in the same strains. These studies suggest that a gene transfer approach to overexpress naturally occurring antifungal proteins may be useful in the management of mucosal candidiasis.

Adenoviridae↗

PubMed1996

Candidacidal activity of human salivary histatin recombinant variants produced by site-directed mutagenesis.

Histatin 5 (Hst5) is a 24-amino acid (aa) member of the Hst family that is found in human salivary secretions and exhibits candidacidal activity. Hst5 contains a 13-aa region that alone is capable of killing fungal pathogens and is referred to as the functional domain. To investigate the role of specific aa located within the functional domain, the pRSET bacterial expression system was used to produce recombinant Hst5 (re-Hst5) and several re-variants that were generated by site-directed mutagenesis. The vector pRSETC expresses genes of interest as fusion proteins attached to the carboxy end of an N-terminal His6 tag that binds to nickel (Ni2+). The re-variants were generated using the polymerase chain reaction (PCR) and had Gly substituted for either the His, Glu or Lys/Arg within the functional domain. PCR products that encoded either the wild-type or variant forms of re-Hst5 were inserted into pRSETC and produced as fusion proteins which were affinity purified from cell lysates by Ni(2+)-Sepharose chromatography. Fusion proteins were digested with CNBr and re-Hsts were purified by reversed-phase high performance liquid chromatography (RP-HPLC). Re-Hsts were tested in bioassays to measure the ability to kill both Candida albicans (C. albicans) blastoconidia and spheroplasts which were generated by removal of the cell wall. In both assays, re-Hst5 displayed dose-dependent candidacidal activity that was nearly identical to that of native Hst5 purified from human salivary secretions. Re-Hst5 variants with either Glu or Lys/Arg substitutions demonstrated significantly lower candidacidal activity in both assays, while the variant with His mutated showed essentially no activity at physiological concentrations. These results indicate that acidic and basic aa within the functional domain contribute to candidacidal activity and that the His are essential for candidacidal activity. Additionally, since C. albicans spheroplasts were also susceptible to Hsts, the cell wall is not an essential component in the Hst mechanism of candidacidal action.

Amino Acid Sequence↗

PubMed1996

Temporal and compositional characteristics of salivary protein adsorption to hydroxyapatite.

Salivary proteins bind to enamel surfaces and hydroxyapatite in a highly selective manner. Numerous studies have identified these proteins as primarily proline-rich proteins, cystatins, statherin, and histatins. Previously, the hydroxyapatite-binding potential of these proteins had been characterized in systems consisting of singly purified protein and adsorbent. The purpose of this study was to investigate the adsorption of each protein in the presence of complete salivary secretion. Proteins, shown to adsorb to hydroxyapatite, were purified, biotinylated, and added back to the remaining proteins to form a series of reconstituted secretions. The adsorption of each biotinylated protein in the reconstituted secretion to hydroxyapatite was then measured as a function of time. Results indicated that three different adsorption patterns occur. A simple hyperbolic pattern is characteristic of amylase, glycosylated proline-rich protein (PRG), and cystatin. A faster adsorption process is observed for PRP-3, PRP-4, PIF-f, and statherin. A more complex pattern, exhibiting a rapid phase followed by a slower phase, is characteristic of PRP-1, PRP-2, PIF-s, and histatins. These results suggest that there are different adsorption processes involved in the binding of salivary proteins to hydroxyapatite. Two possible mechanisms are direct adsorption of protein to hydroxyapatite and indirect adsorption of protein by interacting with other proteins already bound to hydroxyapatite.

Adsorption↗

PubMed1995

Molecular cloning of a novel high molecular weight mucin (MG1) from human sublingual gland.

A human sublingual gland cDNA library was screened with a polyclonal antiserum against deglycosylated MG1 and a positive clone, pSM2-1, was isolated which codes for 196 amino acids in the carboxyl-terminal region of this mucin. This region is cysteine-rich and contains a C2-like domain upstream of the extreme carboxyl-terminal domain in which the arrangement of cysteines is nearly identical to that in human von Willebrand factor, human intestinal mucin MUC2, human tracheobronchial mucin MUC5 and porcine and bovine submaxillary gland mucins. Northern analyses with pSM2-1 showed MG1 transcripts are abundant in sublingual gland and barely detectable in submandibular gland. This study provides the first primary sequence data on human salivary mucin MG1 and the significance of the results is discussed with respect to the biosynthesis and differential expression of MG1 in human salivary glands.

Amino Acid Sequence↗

PubMed1995

Recombinant histatins: functional domain duplication enhances candidacidal activity.

Histatin 3 (Hst3) is a 32-amino-acid (aa) His-rich protein with antimicrobial activity found in human salivary secretions. To explore further the structure/function relationship of Hst, we utilized a bacterial system for the efficient production of recombinant Hst3 (re-Hst3) and Hst variants. Previously, we demonstrated that the middle portion of Hst3 (aa 13-24) contains the functional domain responsible for killing Candida albicans. Using PCR and splice overlap extension, a Hst variant (re-Hst3rep) was made in which the functional domain was repeated in tandem. Using the pRSET bacterial expression system, re-Hst3 and the variant re-Hst3rep were produced as chimeric fusions and were isolated from bacterial sonicates by affinity chromatography. Affinity purified fusion proteins were digested with CNBr and re-Hst were separated from their fusion partners by reverse-phase high-performance liquid chromatography. The activity of re-Hst3 and re-Hst3rep was compared to that of native Hst3 from human salivary secretions in the C. albicans killing assay. The LD50 values for candidacidal activity of native Hst3, re-Hst3 and re-Hst3rep were 7.2, 6.8 and 4.1 nmol/ml, respectively. At lower concentrations re-Hst3rep was five times more active than native Hst3 or re-Hst3 and at even lower concentrations re-Hst3rep exhibited significant candidacidal activity while native Hst3 and re-Hst3 were inactive. These results demonstrate an expression system for production of biologically active functional Hst and Hst variants and shows that repetition of the functional domain of Hst3 enhances candidacidal activity.

Amino Acid Sequence↗

PubMed1995

Functional comparison of native and recombinant human salivary histatin 1.

Histatin 1 is a histidine-rich phosphoprotein present in human parotid saliva that possesses candidacidal activity and functions in mineralization by adsorbing to hydroxyapatite. The objective of the present study was to develop a system for recombinant production of histatin 1 and to examine the role of phosphorylation in the functional activities of this molecule. Native histatin 1 (containing a phosphoserine at residue 2) was purified from parotid saliva, whereas a bacterial expression system was used to produce a recombinant form of histatin 1 (re-Hst1) that lacked phosphorylated serine. Histatin 1 cDNA was inserted into the vector pGEX-3X, which expresses foreign genes as soluble fusion proteins attached to the carboxyl-terminus of glutathione S-transferase (GST). The GST/re-Hst1 fusion protein was isolated from cell lysates by affinity chromatography on glutathione (GSH)-Sepharose and digested with cyanogen bromide to separate re-Hst1 from the GST fusion partner. The digest was subjected to reversed-phase high-performance liquid chromatography on a C18 column, and re-Hst1 was eluted as a well-defined peak. The yield of re-Hst1 was 4 mg/L of bacterial culture. Amino-terminal sequencing and amino acid analysis confirmed the final product as re-Hst1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that native histatin 1 and re-Hst1 had the same apparent molecular weights, while cationic PAGE showed that re-Hst1 was more basic. Phosphate analysis indicated 1 mol phosphate/mol of native histatin 1, while re-Hst1 lacked any detectable phosphate. Re-Hst1 demonstrated candidacidal activity comparable to that of native histatin 1, but displayed substantially lower binding to hydroxyapatite. These results show that phosphorylation of histatin 1 at residue 2 contributes significantly to its ability to bind to hydroxyapatite.

Antifungal Agents↗

PubMed1994

Antisense RNA to the first N-glycosylation gene, ALG7, inhibits protein N-glycosylation and secretion by Xenopus oocytes.

N-Glycosylation has been shown to affect the rate of glycoprotein transport through the secretory pathway. In order to identify the critical components in the N-glycosylation pathway that directly influence protein secretion, we have studied the effects of downregulation of the first gene in the dolichol pathway, ALG7, on the synthesis, glycosylation and secretion of native and heterologous proteins by Xenopus laevis oocytes. Our strategy involved the use of ALG7 antisense RNA (asRNA) to lower the effective abundance of the ALG7 protein in oocytes. The results showed that there was an inverse dose-response relationship between ALG7 asRNA and the amount of glycosylated and secreted proteins. These effects were also observed for heterologously expressed rat parotid amylase. Since ALG7 asRNA did not inhibit overall protein synthesis, we conclude that downregulation of ALG7 expression directly lowered protein export.

Amylases↗

PubMed1994

Physiological regulation of the secretion of histatins and statherins in human parotid saliva.

The small salivary phosphoproteins, histatins and statherins, have important functions in the oral cavity in terms of antimicrobial actions and regulation of calcium phosphate homeostasis. Neither the effects of various physiological stimuli on their secretion nor the nature of the efferent receptor involved in the stimulus-secretion coupling has been determined previously. These aspects are important for improved understanding of the secretory control of salivary proteins and may have implications regarding the effects of specific medications on salivary constituents and oral health. The effects of graded mechanical (chewing on short and long silicone tubings) and gustatory stimulation (0.5, 1.5, and 5.0% citric acid) on the secretion of histatins and statherins were studied in the presence and absence of adrenolytic agents (n = 10). In this model, secretory rates of both proteins increased with increases in flow rate, with 5.0% citric acid representing a particularly potent stimulus. Histatin and statherin secretory rates were significantly reduced by the beta 1-adrenolytic agent (histatins to 58 to 72% and statherins to 11 to 29% of that in corresponding control experiments), but not by the alpha 1-adrenolytic agent. Since the beta 1-adrenergic receptors played an important role in the stimulus-secretion coupling of these proteins, protective salivary functions in the oral cavity may be compromised during beta 1-adrenolytic treatment.

Adult↗

PubMed1993

Structural features of salivary function.

Saliva plays an important role in the maintenance of oral health by exhibiting multiple host defense functions. These include homeostatic processes, lubrication, antimicrobial activity, and the control of demineralization/remineralization of teeth. Biochemical studies of saliva and salivary secretions established that specific salivary proteins are responsible for these defense functions. Because some of these salivary proteins have been characterized extensively, including their primary structures, it has become feasible to explore their structure/function relationships. Acidic proline-rich proteins (PRPs), for example, exhibit high affinity to hydroxyapatite, inhibit crystal growth of calcium phosphate salts from solutions supersaturated with respect to hydroxyapatite, bind calcium ions, and interact with several oral bacteria on adsorption to hydroxyapatite. Statherins, histatins, and cystatins also exhibit affinities to mineral surfaces, inhibit calcium phosphate precipitation, and play a role in maintaining the integrity of teeth. Furthermore, histatins exhibit both antibacterial and antifungal activities. Approaches to identifying the functional domains of these salivary proteins include functional assays of enzymatically digested proteins and peptides, synthetic peptides and peptide analogues, and chemically modified proteins as well as biophysical studies of native proteins or peptides. Such studies have demonstrated that the fungicidal activities of histatins reside in the middle portion of the polypeptide chain, whereas the hydroxyapatite binding domains of PRPs and statherin reside in the phosphorylated amino-terminal regions. Identification of functional domains is vital in understanding the mechanisms of action and this information can be exploited in the development of therapeutic agents.

Amino Acid Sequence↗

PubMed1992

Adsorption of human salivary proteins to hydroxyapatite: a comparison between whole saliva and glandular salivary secretions.

The protein compositions of in vitro pellicles formed from whole saliva and parotid and submandibular secretions were determined by use of synthetic hydroxyapatite as a model for dental enamel. The adsorbed and unadsorbed protein fractions were analyzed by amino acid analysis and both anionic and cationic discontinuous polyacrylamide gel electrophoresis. For further characterization of the in vitro pellicle, the adsorbed fractions were subjected to gel filtration on Sephadex G-100 and reversed-phase chromatography on C18 columns. Amylase, acidic and glycosylated proline-rich proteins, statherins, and histatins were identified in the parotid-derived pellicle. Detailed analysis of the statherin-containing fractions resulted in the observation of several statherin-like proteins. The use of cationic gel electrophoresis allowed for the identification of histatin 3 and histatin 5, which have not been previously detected in pellicle formed in vitro. The protein composition of submandibular-derived pellicle was similar to that of parotid-derived pellicle except for the presence of cystatins and the absence of glycosylated proline-rich proteins. In contrast, in vitro pellicle derived from whole saliva exhibited a vastly different composition, consisting primarily of amylase, acidic proline-rich proteins, cystatins, and proteolytically-derived peptides. The results indicate that acidic phosphoproteins as well as neutral and basic histatins from pure secretions selectively adsorb to hydroxyapatite, whereas in whole saliva some of these proteins are proteolytically degraded, dramatically changing its adsorption pattern.

Adsorption↗

PubMed1991

Salivary cystatin SA-III, a potential precursor of the acquired enamel pellicle, is phosphorylated at both its amino- and carboxyl-terminal regions.

Cystatin SA-III was purified from human submandibular/sublingual glandular secretions by adsorption to hydroxyapatite, gel filtration chromatography, and reversed-phase HPLC. The amino acid sequence of its amino-terminus was deduced by sequential Edman degradation and found to be identical to the first 10 residues of cystatin HSP-12. The purified protein was digested with endoproteinase Asp-N and the digestion products were subjected to fast atom bombardment mass spectroscopy. m/z values corresponding to 12 peptides were aligned to the sequence of cystatin S preceded by the eight-residue amino-terminal peptide detected in HSP-12. This process resulted in the assignment of peptides corresponding with 118 out of the 121 amino acid residues predicted from the nucleotide sequence for cystatin SA-III. In order to align several peptides, it was necessary to substitute four residues of phosphoserine for four residues of serine. Fast atom bombardment mass spectrometry and additional Edman degradation procedures localized the phosphate moieties to Ser-3, Ser-99, Ser-112, and Ser-116. This is the first report of the structure of cystatin SA-III deduced by amino acid sequencing techniques and indicates the sites of phosphoserine within the molecule. Based on these assignments, cystatin SA-III is unique among salivary proteins in that it possesses phosphate groups at its amino-terminus as well as its carboxyl-terminus.

Amino Acid Sequence↗

PubMed1991

Multiple forms of statherin in human salivary secretions.

Sequential chromatography of hydroxyapatite-adsorbed salivary proteins from submandibular/sublingual secretions on Sephadex G-50 and reversed-phase HPLC resulted in the purification of statherin and several statherin variants. Amino acid analysis, Edman degradation and carboxypeptidase digestion of the obtained protein fractions led to the determination of the complete primary structures of statherin SV1, statherin SV2, and statherin SV3. SV1 is identical to statherin but lacks the carboxyl-terminal phenylalanine residue. SV2, lacking residues 6-15, is otherwise identical to statherin. SV3 is identical to SV2 but lacks the carboxyl-terminal phenylalanine. These results provide the first evidence for multiple forms of statherin which are probably derived both by post-translational modification and alternative splicing of the statherin gene.

Adsorption↗

PubMed1991

Anticandidal activity of major human salivary histatins.

We have previously shown that histatins 1, 3, and 5 are homologous, histidine-rich proteins present in human parotid and submandibular secretions which contain 38, 32, and 24 amino acids, respectively. Interest in these proteins stems from the fact that histatins exhibit candidacidal and candidastatic activities. The goal of the present investigation was a detailed functional characterization of these anticandidal activities of histatins at the levels of killing of blastoconidia, killing of germinated cells, and inhibition of germination by using three bioassays. Candidacidal activities were evaluated at several ionic strengths, in the presence of different mono- and divalent ions, and at multiple pH values. In addition, the susceptibility of Candida albicans in different growth phases to histatins was investigated. While all three major human histatins demonstrated candidacidal activities, they differed in their abilities to kill blastoconidia and germinated cells, with histatin 5 being the most active, histatin 3 showing moderate activity, and histatin 1 exhibiting the lowest level of activity. For the inhibition of germination, however, histatin 3 exhibited more activity than either histatin 1 or histatin 5. The candidacidal activity of histatins was inversely proportional to both the ionic strength and the divalent cation concentration in the medium. Stepwise reduction of the pH of the assay medium enhanced the candidacidal activities of histatins 1 and 3, while the activity of histatin 5 was pH independent over the range of pHs 4 to 8. C. albicans in log-phase growth was more susceptible to histatins 1 and 3 than cells in stationary phase. Cells in either growth phase were still more vulnerable to histatin 5 than to histatins 1 and 3. The results obtained establish the functional relationship of the major histatins with respect to both their fungicidal and fungistatic activities and provide insights into their activities under ionic and pH conditions likely to be encountered in vivo in the oral cavity. Moreover, the data point towards possible mechanisms responsible for the anticandidal activities of histatins.

Amino Acid Sequence↗

PubMed1991

Biosynthesis and secretion of rat salivary proteins by Xenopus laevis oocytes.

Xenopus laevis oocytes injected with poly (A+) RNA isolated from rat parotid and submandibular glands synthesize and secrete salivary proteins. Amylase was identified in the media of cultured oocytes injected with rat parotid mRNA by size and immunoprecipitation with anti-human amylase serum. Secretion of the salivary proteins was detectable in the medium eight h following the parotid mRNA injection and continued in a time-dependent fashion for up to 96 h. In contrast to rat parotid slices in culture, which demonstrate a regulated pathway of secretion highly responsive to the secretagogue isoproterenol, secretion of salivary proteins by oocytes did not respond to the stimulation by isoproterenol. Though parotid mRNA is presumed to contain the templates encoding the regulated pathway of secretion, reconstitution of this pathway of secretion in oocytes was not observed in our experiments. Since Xenopus laevis oocytes secrete constitutively significant amounts of proteins when injected with salivary gland mRNA, they are a useful biological system for the analysis of secretion, processing, and function of salivary proteins.

Animals↗