Chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women.

Common pharmacological treatments of mood disorders aim to modulate serotonergic neurotransmission and enhance serotonin levels in the brain. Brain serotonin levels are dependent on the availability of its food-derived precursor essential amino acid tryptophan (Trp). We tested the hypothesis that delivery of Trp via food may serve as an alternative treatment, and examined the effects of a Trp-rich, bioavailable dietary supplement from egg protein hydrolysate on cognitive and emotional functions, mood state, and sleep quality. In a randomised, placebo-controlled, parallel trial, fifty-nine mentally and physically healthy women aged 45-65 years received placebo (n 30) or the supplement (n 29) (both as 0.5 g twice per d) for 19 d. Emotional processing was significantly changed by supplementation, exhibiting a shift in bias away from negative stimuli. The results for the Affective Go/No-Go Task exhibited a slowing of responses to negative words, suggesting reduced attention to negative emotional stimuli. The results for the Facial Emotional Expression Rating Task also supported a shift away from attention to negative emotions and a bias towards happiness. An increase in arousal-like symptoms, labelled 'high energy', shorter reaction times and a slight benefit to sustained attention were observed in the treated subjects. Finally, when the supplement was taken 60-90 min before bedtime, a feeling of happiness before going to bed was consistently reported. In summary, daily consumption of a low-dose supplement containing bioavailable Trp may have beneficial effects on emotional and cognitive functions.

High genetic diversity and zoonotic potential of Staphylococcus aureus strains recovered from bovine intramammary infections in Colombians dairy herds.

Genotyping of Staphylococcus aureus isolated from mastitis has become a fundamental tool to understand its complex epidemiology and to evaluate spillover events. The aim of this study was to describe the frequency of genotypes of the S. aureus strains isolated from intramammary infections by spa typing technique, and to evaluate the association between genotypes and the ability to form biofilm under in vitro conditions. Sixty-six strains of S. aureus recovered from bovines intramammary infections on 56 dairy herds located in 14 municipalities of the department of Antioquia were characterized. The majority of strains (65/66) were isolated from milk samples collected from dairy cows with subclinical intramammary infections. Nineteen different spa types were found in this study, t521 (19.70%), t267 (15.15%), and t605 (12.12%) being the most frequent. The strains from the t605 spa type showed the highest biofilm production. The high frequency of spa types with zoonotic potential found in this study, identified cattle as an important reservoir of theses clones for people in close proximity, such as milkers and consumers of unpasteurized dairy products.

Aerosol-assisted CVD method for the synthesis of solid particles of t-YSZ-Fe3O4.

This work details the production of solid composite particles by the aerosol-assisted chemical vapor deposition method. With this method it is feasible to produce at low temperature (450 °C) the tetragonal phase of zirconium oxide stabilizing it with yttrium oxide (YSZ) and cubic iron oxide (Fe3O4) at the same time. The particles have a solid morphology in which both metal oxides coexist without mixing. The average size of the obtained particles is 329 ± 81 nm, moreover, each particle is formed by thousands of crystallites of size 2 ± 0.5 nm. The formation of solid structures is due to the amount of Zr and Y found in each particle. These particles can be applied as reinforcements of metallic structures. •A simple and low-cost method for producing composite particles to be applied as reinforcing agents for metal structures.•The particles are formed by two phases of tetragonal yttria-stabilized zirconia (t-YSZ) and cubic Fe3O4, which was synthesized following a one-step process via the aerosol-assisted chemical vapor deposition method (AACVD).•The tetragonal phase of ZrO2 is obtained at 450 °C stabilizing it with ∼3.8% of yttrium oxide.

Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls.

INTRODUCTION: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease. OBJECTIVE: To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU(rs227959 and rs11136000) in patients with MCI and healthy individuals. METHODOLOGY: We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics. RESULTS: We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend towards poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance. DISCUSSION: Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples.

Genotypic and phenotypic characterization of biofilm production by Staphylococcus aureus strains isolated from bovine intramammary infections in Colombian dairy farms.

The ability of Staphylococcus aureus to form biofilms is an important virulence factor because this has been associated with persistent bovine intramammary infections. Different mechanisms of biofilm formation have been described in S. aureus; however, the process has been found to be mainly driven by the ica and bap genes. The presence of the ica and bap genes, as well as the biofilm formation in vitro were evaluated in 229 S. aureus strains isolated from bovine milk collected from different regions of Department of Antioquia, Colombia. Three different genotypes grouped into three separate clusters were identified from in vitro assays. Genotype 1 (ica positive and bap negative) was the most prevalent (78.17%), followed by genotype 2 (ica and bap positive) (12.66%) and genotype 0 (ica and bap negative) (9.17%). Biofilm formation was observed in 81.26% of the strains from which 100% of genotype 2 isolates showed biofilm formation. The biofilms formed by genotype 2 isolates were also found to have the highest optical density (>2.4). These results showed that most of the S. aureus strains were capable of biofilm formation, suggesting the virulence potential particularly in bap-positive strains.

Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls. / Análisis de desempeños cognitivos y polimorfismos en SORL, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU y BIN1 en pacientes con trastorno neurocognitivo leve y en sujetos cognitivamente sanos.

INTRODUCTION: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease. OBJECTIVE: To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ɛ2, ɛ3, ɛ4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU (rs227959 and rs11136000) in patients with MCI and healthy individuals. METHODOLOGY: We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics. RESULTS: We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend toward poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance. DISCUSSION: Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples.

Riesgo de caídas en personas mayores: comparación de resultados pre y postaplicación de un programa de ejercicios multicomponentes basado en subsistemas de la estabilidad postural / Comparison of the risk of falls in older people before and after to application of a multicomponent exercise program based on subsystems of postural stability

Antecedentes y objetivo: Los programas de ejercicios de componentes múltiples han demostrado una adecuada efectividad en personas mayores. Sin embargo, no siempre muestran beneficios directos sobre la estabilidad y el riesgo de caídas. Esto implica la necesidad de aplicar estos programas de ejercicios con un fuerte componente de entrenamiento de la estabilidad postural. El objetivo fue comparar el riesgo de caídas antes y después de la aplicación de un programa de ejercicios de componentes múltiples basado en componentes específicos de estabilidad postural. Materiales y métodos: Mediante un estudio cuasi experimental, participaron 72 personas mayores de 60 años y más, las que fueron evaluadas basalmente con las siguientes pruebas clínicas: Five Times Sit to Stand(FTST); Estación unipodal (EUP); Timed Up and Go (TUG); Self-Selected Walking Speed (SSWS) y Falls Efficacy Scale (FES). Posteriormente se realizó una intervención de 12 sesiones de 45min/3 veces por semana, que consistió en un programa de ejercicios de componentes múltiples con 6 estaciones de ejercicios de acondicionamiento físico y estabilidad. Un mes después los voluntarios fueron evaluados nuevamente. Resultados: Se observaron mejoras significativas en las pruebas FTST (p<0,0001); EUP derecha (p=0,006), EUP izquierda (p=0,010) y TUG (p<0,0001). No hubo cambios significativos en las pruebas SSWS (p=0,938) y FES (0,767). Conclusiones: El entrenamiento de componentes múltiples basados en subsistemas de la estabilidad, postural podría estar asociado a una mejora significativa en el rendimiento de las pruebas de EUP, TUG y FTST, y con ello a una posible reducción del riesgo de caídas.

Background and objective: Multicomponent Exercise Programs have shown adequate effectiveness in older people. However, they do not always show direct benefits on balance and risk of falls. This implies the need to apply these exercise programs with a strong a strong postural stability training component. The objective was to compare the risk of falls before and after the application of an Multicomponent Exercise Program based on specific components of postural stability. Material and methods: Through a quasi-experimental research, 72 people aged 60 years and over participated, who were evaluated based on the following clinical tests: Five Times Sit to Stand (FTST); Unipedal Stance Test (UST); Timed Up and Go (TUG); Self-Selected Walking Speed (SSWS) and Falls Efficacy Scale (FES). Subsequently, an intervention of 12 45-minute sessions was carried out three times per week, which consisted of a Multicomponent Exercise Program with 6 specific stations of physical conditioning and stability exercises. A month later the volunteers were evaluated again. Results: Significant improvements were observed in the FTST tests (P<.0001); Right EUP (P=.006), Left EUP (P=.010) and TUG (P<.0001). There were no significant changes in the SSWS tests (P=.938), and FES (.767). Conclusions: The multicomponent training plan based on postural stability subsystems could be associated with the best significant performance in the EUP, TUG and FTST tests, and with it to a possible reduction of the risk of falls.

Clinical significance of the ABCB1 and ABCG2 gene expression levels in acute lymphoblastic leukemia.

OBJECTIVES: Acute lymphoblastic leukemia (ALL) is a clonal disease that accounts for 20% of acute leukemias in adults. A high percentage of adult patients (ranging from 70 to 80%) reach complete remission; however, the 5-year survival rate is only 20-40%. One of the main obstacles to treatment success is the drug resistance of leukemic cells. Therefore, our research group analyzed the ABCB1 and ABCG2 gene expression levels in 61 patients diagnosed with ALL and assessed whether the levels affected the clinical parameters and 40-month survival rate. METHODS: The ABCB1 and ABCG2 gene expression levels were analyzed using real-time polymerase chain reaction in 61 patients diagnosed with ALL and 99 healthy donors as controls. The association between ABCB1 and ABCG2 gene expression levels and clinical variables was determined using the Chi-square test and Fisher's exact test. Overall survival (OS) was determined using the Kaplan-Meier method. RESULTS: The results showed high ABCB1 and ABCG2 gene levels, which were 4.5 and 2.3 times the levels of healthy donors, respectively. A total of 52% of the study patients expressed high ABCB1 levels and were significantly associated with the high-risk patient group and a decreased 40-month survival rate of 78%. Only 49% of the patients expressed high ABCG2 gene levels. No association was found between the clinical parameters and the ABCG2 gene expression levels. CONCLUSIONS: Early detection of ABCB1 gene expression levels could be important for the diagnosis and monitoring of ALL patients.

Análisis de desempeños cognitivos y polimorfismos en SORL, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU y BIN1 en pacientes con trastorno neurocognitivo leve y en sujetos cognitivamente sanos / Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls

Introducción: Los polimorfismos de riesgo para el desarrollo de enfermedad de Alzheimer (se han estudiado en pacientes con demencia, pero aún no se han explorado en trastorno neurocognitivo leve (TNL) en nuestra población, ni se han considerado en relación con variables cognitivas, las cuales pueden ser biomarcadores predictivos de enfermedad.ObjetivoEvaluar los desempeños cognitivos y los polimorfismos en los genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE(isoformas ɛ2, ɛ3, ɛ4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN(rs744373), CLU (rs227959 y rs11136000) en pacientes con TNL y en sujetos sanos.MetodologíaEstudio descriptivo, exploratorio y transversal, en una cohorte prospectiva de participantes seleccionados mediante muestreo no probabilístico, evaluados por neurología, neuropsicología y genética, y clasificados como cognitivamente sanos y pacientes con TNL, según criterios. La cognición se evaluó por medio de la batería Neuronorma y se analizó en relación con las variantes polimórficas por medio de medidas de tendencia, intervalos de confianza y estadísticos no paramétricos.ResultadosSe identificaron diferencias en los desempeños en tareas de lenguaje y memoria en relación con las variantes de BIN1, CLU y CR1, junto con tendencias en las variantes de PICALM, GWArs, SORL y PVRL2, mientras que en APOE y TOMM40 no se encontraron tendencias.DiscusiónLas tendencias en los desempeños cognitivos en relación con variantes polimórficas podrían indicar que, en ausencia de demencia, los mecanismos que regulan estos genes podrían tener un efecto sobre la cognición; sin embargo, esta aproximación tiene un carácter exploratorio y sus resultados permiten generar hipótesis que requieren ser exploradas en muestras de mayor tamaño. (AU)

Introduction: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease.ObjectiveTo evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ɛ2, ɛ3, ɛ4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU (rs227959 and rs11136000) in patients with MCI and healthy individuals.MethodologyWe performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics.ResultsWe found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend toward poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance.DiscussionDifferences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples. (AU)

Synthesis and antitumor evaluations of symmetrically and unsymmetrically substituted 1,4-bis[(aminoalkyl)amino]anthracene-9,10-diones and 1,4-bis[(aminoalkyl)amino]-5,8-dihydroxyanthracene-9,10-diones.

The ipso bis displacements of fluoride from 1,4-difluoroanthracene-9,10-dione (3) and 1,4-difluoro-5,8-dihydroxyanthracene-9,10-dione (4) by excess of a diamine (or a monoamine) in pyridine at room temperature lead to the symmetrically substituted 1,4-bis-substituted analogues 5 and 6, respectively. The ipso monodisplacements of fluoride from 3 and 4 can be accomplished by treatment with less than 1 molar equiv of a diamine (or a monoamine) to yield 7 and 8, respectively. Treatment of 7 or 8 with a different diamine leads to the unsymmetrically substituted 1,4-bis[(aminoalkyl)amino]anthracene-9,10-diones 9 and 10, respectively. Many of the synthetic unsymmetrical analogues have been evaluated for their antitumor activity against L1210 in vitro and in vivo. Cross resistance of analogue 10a with mitoxantrone (2) and doxorubicin was evaluated against MDR lines in vitro against human colon carcinoma LOVO and its subline resistant to DOXO (LOVO/DOXO). Potential mechanisms for the observed cytotoxicity are presented and discussed.

Natural defenses against Candida colonization breakdown in the oral cavities of the elderly.

Candida colonization of the oral cavity increases in the elderly. A major predisposing condition is denture use, which also increases in the elderly. To test whether the increase in colonization is age-related in a fashion independent of denture use, we analyzed the frequency (incidence) of carriage, the intensity of carriage, the multiplicity of species, and the genetic relatedness of strains in the oral cavities of 93 test subjects separated into the three age groups: 60 to 69 yr, 70 to 79 yr, and > or = 80 yr. Each age group was further subdivided into subjects with and without dentures, and into males and females. The results demonstrate that the frequency of carriage, the intensity of carriage, and multispecies carriage all increase as a function of age and differ according to gender, in both cases independent of denture use, suggesting that the natural suppression of yeast carriage in the oral cavity breaks down in the elderly. In addition, it is demonstrated that Candida glabrata colonizes the oral cavities of elderly individuals without dentures only after 80 yr of age, suggesting that there are age-related compromising conditions other than denture use in this most elderly age group.

Diagnostic and therapeutic potential of poly(benzyl L-glutamate).

Poly(benzyl L-glutamate) (PBLG) microcapsules, prepared by a solvent evaporation technique for intravenous injection, are evaluated for their potential use in diagnostic computed tomographic enhancement of liver images. The smaller microcapsules, < 3 microns, loaded with a radiopaque contrast material, ethyl iopanoate (IOPAE), produced prolonged opacification of the liver when delivered intravenously. In vivo tissue distribution studies of PBLG-131I-IOPAE (5 microCi/rat, iv) showed that liver had the highest uptake (percent of injected dose/g of tissue) among other organs 24 h postinjection. An in vitro estrogen receptor assay in pig uteri indicated that PBLG conjugated with estrone did not interfere with estrogen receptor affinity, suggesting the estrogen therapy potential of PBLG-estrone.

Resistance of Rowett athymic (nude) rats to casein-induced amyloidosis.

Rowett athymic (nude) rats (n = 18) were injected subcutaneously (36 to 86 injections) or intraperitoneally (10 to 56 injections) with 10% casein solution to attempt to induce amyloidosis. Neither the injected nor the control rats had gross or microscopic evidence of amyloid deposition. Serum beta- and gamma-globulin concentrations were significantly higher in the injected rats than in the control rats. There were no significant changes in blood urea nitrogen or serum alanine aminotransferase values of the experimental groups compared to the control groups. The relationship of amyloidosis to deficient cell-mediated immunity and the use of the nude rat for the study of the pathogenesis of amyloidosis are discussed.

Enhanced bactericidal activity of Arm and Hammer Dental Care.

PURPOSE: To compare and contrast antibacterial activities of a baking soda-containing dentifrice, Arm and Hammer Dental Care (AHDC) with two fluoride dentifrices without baking soda (Crest and Colgate). MATERIALS AND METHODS: A biphasic approach was taken, utilizing newly-developed laboratory model systems to: (1) assess the activity of brief exposure to dentifrices on single and mixed cultures; and (2) determine the effect of multiple, short-term exposure of sucrose-colonized Streptococcus mutans to simulate cumulative activity against cariogenic plaque. RESULTS: The short-term exposure assays revealed that S. mutans was significantly more susceptible to AHDC than either Crest of Colgate (P<0.05). Moreover, exposure of mixed suspensions of bacteria by AHDC resulted in complete killing of Actinomyces viscosus and significantly greater decreases in S. mutans (P<0.05). This enhanced bactericidal effect was not due to an alkaline pH as pH-adjusted AHDC solutions exhibited similar activity. The comprehensive in vitro plaque studies showed that exposure of colonized S. mutans to AHDC resulted in significantly greater decreases in numbers of viable cells than Crest (P<0.05). Under the conditions employed, the baking soda-containing AHDC exhibited greater antibacterial efficacy overall than the standard Crest or Colgate pastes. These studies suggest that the use of AHDC may provide additional clinical benefit as a result of the enhanced bactericidal activity.

Effects of acute treatment with a tryptophan-rich protein hydrolysate on plasma amino acids, mood and emotional functioning in older women.

RATIONALE: Effective functioning of the neurotransmitter serotonin is important for optimal cognitive and emotional function. Dietary supplements able to increase availability to the brain of the precursor amino acid, tryptophan (TRP), and thereby enhance serotonin synthesis, can have measurable impact on these psychological processes. OBJECTIVES: This study involves a randomised controlled trial of a TRP-rich egg-white protein hydrolysate (DSM Nutritional Products Ltd., Switzerland) on plasma amino acids, cognition, mood and emotional processing in older women. METHODS: Following a baseline test day without treatment, 60 healthy women aged 45-65 years received drinks containing either 2 or 4 g of TRP-rich protein hydrolysate product or 3.11 g casein hydrolysate as a control. One hour later, they undertook a 2-h battery of cognitive and emotional tests. RESULTS: The TRP-rich protein hydrolysate produced the expected dose-dependent increase in the ratio of plasma TRP to competing large neutral amino acids. TRP-rich protein hydrolysate (2 g only) prevented both the decline in wellbeing and increase in fatigue seen over the test session in the control group. This treatment dose resulted in a significant shift in emotional processing towards positive words and reduced negative bias in assessing negative facial expressions. Effects on cognition were small and not statistically reliable and are not reported here. However, there was no evidence for any adverse effects. CONCLUSIONS: Consumption of a low dose of TRP-rich protein hydrolysate may have beneficial effects on emotional function that could promote feelings of wellbeing, possibly conferring resistance to deterioration in mood in healthy subjects or depressive episodes.

Clinical and pathological characteristics of polymethylmethacrylate and hyaluronic acid in the rat tongue.

Adverse effects on the oral mucosa after the use of dermal fillers have been increasingly reported due to their increased use for facial aesthetics. The objective of this study was to evaluate the clinical and histologic effects of two types of product, 10% polymethylmethacrylate and 20mg/ml hyaluronic acid, locally and at long distance, examining initial and late reactions. Each substance was randomly and separately injected in rats' tongues (polymethylmethacrylate, n = 16; hyaluronic acid, n = 18). They were compared with the control group (n = 16) at 3 observation times (7, 60 and 90 days) for clinical analysis, intensity of local inflammatory response (haematoxylin and eosin staining), amount of newly formed blood vessels and macrophages (immunohistochemical assays), density of collagen fibres (picrosirius staining) and systemic migration of the product to the liver and kidney (haematoxylin and eosin staining). The results showed inflammation triggered by the injection of the material, suggesting that both substances cause responses in local tissue, although there was biocompatibility with hyaluronic acid. This research highlights the importance of experimental studies on this subject, since adverse reactions have been observed routinely in dental practice.

Differences in adhesion of Candida albicans 3153A cells exhibiting switch phenotypes to buccal epithelium and stratum corneum.

Cells of the laboratory strain 3153A of Candida albicans can be stimulated to undergo high-frequency phenotypic switching by a low dose of UV. We have compared the adhesive properties of cells exhibiting the basic original smooth (o-smooth) phenotype and three switch phenotypes (star, irregular wrinkle, and revertant smooth) to buccal epithelium and stratum corneum. The generalized hierarchy of adhesion is as follows: o-smooth > irregular wrinkle > revertant smooth > star. This is the inverse of the hierarchy of the proportions of elongate hyphae formed by these phenotypes in culture. These results suggest that the differences in adhesion between o-smooth and the three switch phenotypes of strain 3153A reflect, at least in part, the level of interference due to the formation of elongate hyphae, which tend to cause clumping in suspension. No major differences in the levels of adhesion of cells of the different phenotypes between buccal epithelium and stratum corneum were observed. Results which demonstrate that buccal epithelium induces germination (hypha formation) by conditioning the medium are also presented.

Developmental and molecular biology of switching in Candida albicans.

Candida albicans and related species switch frequently and reversibly between a number of general phenotypes usually discriminated by colony morphology and in some cases by cellular morphology. Switching has been demonstrated to affect a number of physiologic and architectural characteristics of single cells including most of the putative virulence factors of C.albicans. In the past few years, we have cloned several genes regulated by switching in the white-opaque transition of C.albicans strain WO-1. Two of the genes, PEP1 and Op4, are transcribed only in the opaque phase, and one of the genes, Wh11, is transcribed only in the white phase. These coordinately regulated genes are unlinked in the genome and do not undergo sequence reorganization in switching. With the identification of a cis-acting regulatory sequence in the five-prime flanking sequence of Wh11, we now believe that phase-specific genes are regulated by transacting factors and that these factors may be coded for or under the direct regulation of a single master regulatory gene at which site the basic switch event occurs.

Development and characterization of complex DNA fingerprinting probes for the infectious yeast Candida dubliniensis.

Using a strategy to clone large genomic sequences containing repetitive elements from the infectious yeast Candida dubliniensis, the three unrelated sequences Cd1, Cd24, and Cd25, with respective molecular sizes of 15,500, 10,000, and 16,000 bp, were cloned and analyzed for their efficacy as DNA fingerprinting probes. Each generated a complex Southern blot hybridization pattern with endonuclease-digested genomic DNA. Cd1 generated an extremely variable pattern that contained all of the bands of the pattern generated by the repeat element RPS of Candida albicans. We demonstrated that Cd1 does not contain RPS but does contain a repeat element associated with RPS throughout the C. dubliniensis genome. The Cd1 pattern was the least stable over time both in vitro and in vivo and for that reason proved most effective in assessing microevolution. Cd24, which did not exhibit microevolution in vitro, was highly variable in vivo, suggesting in vivo-dependent microevolution. Cd25 was deemed the best probe for broad epidemiological studies, since it was the most stable over time, was the only truly C. dubliniensis-specific probe of the three, generated the most complex pattern, was distributed throughout all C. dubliniensis chromosomes, and separated a worldwide collection of 57 C. dubliniensis isolates into two distinct groups. The presence of a species-specific repetitive element in Cd25 adds weight to the already substantial evidence that C. dubliniensis represents a bona fide species.