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1.
Life Sci ; 212: 168-175, 2018 Nov 01.
Article in English | MEDLINE | ID: mdl-30292829

ABSTRACT

Liver cirrhosis is associated with a wide range of cardiovascular abnormalities including hyperdynamic circulation and cirrhotic cardiomyopathy. The pathogenic mechanisms of these cardiovascular changes are multifactorial and include vascular dysregulations. AIM: The present study tested the hypothesis that the systemic vascular hyporesponsiveness in thioacetamide (TAA)-induced liver injury model is dependent on nitric oxide (NO) and cyclooxygenase (COX) derivatives. MAIN METHODS: Wistar rats were treated with TAA for eight weeks to induce liver injury. KEY FINDINGS: The maximal contractile response in concentration-effect curves to phenylephrine was decreased in aorta from TAA-treated rats, but no differences were found in aorta without endothelium, suggesting an endothelium-dependent mechanism in decreased contractile response. There was no difference in the contractile response with and without L-NAME (N(ω)-nitro-l-arginine methyl ester) in rats with liver injury, showing that the TAA treatment impairs NO synthesis. Pre-incubation of the aorta with indomethacin, a COX-inhibitor, normalized the reduced contractile response to phenylephrine in arteries from TAA group. Also, COX-2 and iNOS (inducible nitric oxide syntase) protein expression was increased in aorta from TAA group compared to control group. Animals submitted to TAA treatment had a reduction in systolic blood pressure. Our findings demonstrated that liver injury induced by TAA caused a decrease in aortic contractile response by a COX-dependent mechanism but not by NO release. Also, it was demonstrated an inflammatory process in the aorta of TAA-treated rats by increased expression of COX-2 and iNOS. SIGNIFICANCE: Therefore, there is an essential contribution of COX-2 activation in extra-hepatic vascular dysfunction and inflammation present in cirrhosis induced by TAA.


Subject(s)
Aorta, Thoracic/pathology , Chemical and Drug Induced Liver Injury/physiopathology , Cyclooxygenase 2/metabolism , Endothelium, Vascular/pathology , Thioacetamide/toxicity , Vascular Diseases/etiology , Animals , Aorta, Thoracic/enzymology , Blood Pressure , Chemical and Drug Induced Liver Injury/etiology , Endothelium, Vascular/enzymology , Male , Nitric Oxide/metabolism , Rats , Rats, Wistar , Vascular Diseases/enzymology
2.
Arq. bras. med. vet. zootec. (Online) ; 69(6): 1398-1406, nov.-dez. 2017. ilus, tab
Article in Portuguese | LILACS, VETINDEX | ID: biblio-909825

ABSTRACT

A endometrose é uma alteração degenerativa das glândulas uterinas e do estroma circundante, caracterizada pelo arranjo periglandular de miofibroblastos e pela deposição de matriz extracelular (ECM). O presente trabalho objetivou avaliar a expressão de colágenos tipos I, III e IV e α-actina de músculo liso (α-SMA) nas endometroses equinas, procurando esclarecer a participação dos miofibroblastos na progressão desses processos. Foram utilizadas 24 biópsias uterinas com diagnóstico de endometrose, recebidas pelo Serviço de Patologia Veterinária e de Reprodução Animal da FMVZ, Unesp, Botucatu, SP. Cortes histológicos foram submetidos às técnicas histoquímicas de tricrômico de Masson, picrosirius red sob luz polarizada e ácido periódico de Schiff (PAS) e imuno-histoquímicas para os três tipos de colágeno citados e α-SMA. Ainda, traçou-se um paralelo entre a técnica de picrosirius red e a imunomarcação dos colágenos tipos I e III. A análise histológica revelou que as fibras de colágeno denso correspondem ao colágeno tipo I, predominantes nas endometroses inativa e inativa destrutiva. As fibras de colágeno frouxo correspondem ao colágeno tipo III, predominantes nas endometroses ativas e ativas destrutivas. Nesses mesmos processos, a membrana basal revelou espessamento, aparentemente não relacionado ao colágeno tipo IV, e uma maior imunomarcação de miofibroblastos periglandulares em relação às endometroses inativa e inativa destrutiva. Dessa forma, nota-se que os miofibroblastos estão relacionados ao aumento na deposição de colágeno tipo III nos ninhos fibróticos ativos.(AU)


Endometriosis is a degenerative change of the uterine glands and surrounding stroma, characterized by periglandular arrangement of myofibroblasts and deposition of extracellular matrix (ECM). The aim of this study was to evaluate the expression of collagen type I, III and IV and α-smooth muscle actin (α-SMA) in equine endometriosis, and investigate the role of myofibroblasts in the progression of these processes. A parallel was made with histochemical techniques of Masson's trichrome, Picrosirius Red under polarized light and Periodic Acid-Schiff (PAS). Twenty four uterine biopsies received by the Veterinary Pathology Service and Animal Reproduction of FMVZ, UNESP, Botucatu, SP, were diagnosed with endometriosis. Histological analysis revealed that the orange dense collagen fibers correspond to type I collagen, being prevalent in inactive and inactive destructive endometriosis. The green loose collagen fibers correspond to type III collagen, and are predominant in active and active destructive endometriosis. In the same processes, a greater amount of periglandular myofibroblasts were observed in comparison to inactive and inactive destructive endometriosis. The presence of these cells in active processes are strongly related to an increased deposition of collagen type III in fibrotic nests. Regarding the basement membrane, the active destructive and active endometriosis shows thickening, apparently not related to an increase in expression of type IV collagen. The active destructive and inactive destructive endometriosis exhibited disruption areas in type IV collagen fibers. Thus, it is noted that the myofibroblasts are related to increased deposition of type III collagen in active fibrotic nests.(AU)


Subject(s)
Animals , Female , Actins/analysis , Collagen Type III/analysis , Collagen Type IV/analysis , Collagen Type I/analysis , Endometriosis/physiopathology , Horses , Myofibroblasts , Immunohistochemistry/veterinary
3.
Nat Prod Res ; 31(4): 460-464, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27309978

ABSTRACT

Essential oils (EOs) extracted from Lavandula luisieri and Cymbopogon citratus were tested for their antifungal activity against ten clinical isolates of dermatophytes isolated from cases of tinea pedis. Inhibition of conidial germination and antifungal drug/EO combination assay were tested on two ATCC reference strains of Trichophyton rubrum and Trichophyton mentagrophytes. EOs were characterised by high amount of oxygenated monoterpenes in their composition. Strong antifungal activity was observed for the majority of clinical strains, and fungicidal activity was demonstrated. Positive interaction between L. luisieri EO combined with terbinafine was observed against terbinafine-resistant strain (Tr ATCC MYA-4438). Significative reduction of the germination was observed above 100 µg mL-1. Both oils were safe to macrophage mammalian cells at tested concentration. This study describes the antifungal activity of L. luisieri and C. citratus EOs against dermatophytes, which could be useful in designing new formulations for topical treatments.


Subject(s)
Antifungal Agents/pharmacology , Arthrodermataceae/drug effects , Monoterpenes/pharmacology , Oils, Volatile/pharmacology , Microbial Sensitivity Tests , Oxygen , Trichophyton/drug effects
4.
Transplant Proc ; 46(6): 1839-41, 2014.
Article in English | MEDLINE | ID: mdl-25131049

ABSTRACT

Intestinal failure is a multifaceted condition that may require high-complexity treatment and a multidisciplinary program, including home parenteral nutrition therapy (HPNT) and intestinal transplantation. In this article, we profile a Brazilian single-center experience with 128 cases of HTPN followed for the last 30 years and appraise the referral for potential intestinal and multivisceral transplantation.


Subject(s)
Intestines/transplantation , Parenteral Nutrition, Home/methods , Postoperative Care/methods , Program Evaluation , Referral and Consultation , Adult , Brazil , Female , Humans , Male , Retrospective Studies
5.
Genet Mol Res ; 13(2): 3800-4, 2014 May 16.
Article in English | MEDLINE | ID: mdl-24938466

ABSTRACT

Manioc, Manihot esculenta, is economically important in many tropical and subtropical countries. The genetic variability of the species has not been fully explored, and new information may help expand its use. Molecular markers based on retrotransposons have good potential for analysis of genetic diversity given their abundance in the genome. Eight long terminal repeat retrotransposons were selected for the development of inter-retrotransposon-amplified polymorphism markers. To test these primers, we analyzed 32 varieties from Anori, 30 from Manicoré and 10 Mandiocabas from the Manioc Germplasm Bank at Embrapa Western Amazonia. The six informative primer pairs yielded 20- 60 polymorphic bands, averaging 92% polymorphism (51.7-98.4) and 0.37 heterozygosity (0.17 to 0.40), with a Shannon information index of 0.54 (0.26-0.59). These markers can be used to explore the genetic diversity of manioc.


Subject(s)
Genetic Variation , Manihot/genetics , Polymorphism, Genetic , Retroelements/genetics , DNA, Plant , Genotype , Germ Cells , Microsatellite Repeats/genetics
6.
Nutr Hosp ; 26(4): 834-42, 2011.
Article in English | MEDLINE | ID: mdl-22470032

ABSTRACT

BACKGROUND: Parenteral nutrition (PN) is used to control the nutritional state after severe intestinal resections. Whenever possible, enteral nutrition (EN) is used to promote intestinal rehabilitation and reduce PN dependency. Our aim is to verify whether EN + oral intake (OI) in severe short bowel syndrome (SBS) surgical adult patients can maintain adequate nutritional status in the long term. METHODS: This longitudinal retrospective study included 10 patients followed for 7 post-operative years. Body mass index (BMI), percentage of involuntary loss of usual body weight (UWL), free fat mass (FFM), and fat mass (FM) composition assessed by bioelectric impedance, and laboratory tests were evaluated at 6, 12, 24, 36, 48, 60, 72, and 84 months after surgery. Energy and protein offered in HPN and at long term by HEN+ oral intake (OI), was evaluated at the same periods. The statistical model of generalized estimating equations with p < 0,05 was used. RESULTS: With long term EN + OI there was a progressive increase in the UWL, a decrease in BMI, FFM, and FM (p < 0,05). PN weaning was possible in eight patients. Infection due to central venous catheter (CVC) contamination was the most common complication (1.2 episodes CVC/patient/year). There was an increase in energy and protein intake supply provided by HEN+OI (p < 0.05). All patients survived for at least 2 years, seven for 5 years and six for 7 years of follow-up. CONCLUSIONS: In the long term SBS surgical adult patients fed with HEN+OI couldn't maintain adequate nutritional status with loss of FM and FFM.


Subject(s)
Nutrition Assessment , Parenteral Nutrition, Home/methods , Short Bowel Syndrome/therapy , Adolescent , Adult , Aged , Body Composition , Body Fat Distribution , Body Mass Index , Body Weight/physiology , Catheter-Related Infections/etiology , Electric Impedance , Female , Humans , Longitudinal Studies , Male , Middle Aged , Nutritional Status , Parenteral Nutrition, Home/adverse effects , Retrospective Studies , Short Bowel Syndrome/mortality , Short Bowel Syndrome/physiopathology , Survival , Treatment Outcome , Young Adult
7.
Acta Reumatol Port ; 34(1): 38-43, 2009.
Article in Portuguese | MEDLINE | ID: mdl-19449474

ABSTRACT

UNLABELLED: Trigger Point Disease is a complex clinical condition. Physicians are required to take a multidisciplinary and preventive approach towards the treatment of this disorder, in order to avoid the chronicity of symptoms. The aim of this review is to perform an update on this subject. MATERIALS AND METHODS: An extensive bibliographic review was carried out based on reference text books and published articles. A thorough search through PubMed using the keywords "trigger point", "myofascial pain", "temporomandibular system", and "tender points" was completed. The review was performed in English and the time limit was April 10th 2008. RESULTS: Trigger Point Disease is a disorder not completely clarified - its pathophysiology has been postulated throughout the years, however there is no conclusive theory. CONCLUSION: The articles and texts reviewed underline the need for an early diagnosis of this disease in order to treat its aetiology and avoid the chronicity of symptoms.


Subject(s)
Myofascial Pain Syndromes , Humans , Myofascial Pain Syndromes/diagnosis , Myofascial Pain Syndromes/etiology , Myofascial Pain Syndromes/therapy , Patient Care Team
8.
Nutr Hosp ; 24(1): 32-9, 2009.
Article in English | MEDLINE | ID: mdl-19266110

ABSTRACT

UNLABELLED: Weight loss and resolution of comorbidities is well established after modern bariatric procedures, however chronology of glyco-lipidic biochemical response is still debated. OBJECTIVE: Aiming to analyze this variable as well as its correlation with food amount and composition, a prospective study was designed. METHODOLOGY: Eighty consecutive patients undergoing Roux-en-Y gastric bypass were investigated every three months until one year after surgery. Females only were accepted and variables included general and nutritional course as well as glucose and lipid measurements. Energy intake was documented including percentage of macronutrients in the diet. RESULTS: Surgery was successful with about 71% excess body weight loss at the end of the first year. Mean energy intake on the 4 postoperative quarters was respectively 519.6 +/- 306.6, 836.0 +/- 407.9, 702.1 +/- 313.1 and 868.8 +/- 342.8 kcal/day (mean +/- SD). Fat intake was initially low but reached 34.1 +/- 7.9% of total calories at final measurement. Blood glucose and lipid fractions tended to be borderline or abnormal preoperatively, and favorably changed by 12 months. Consumption of glucose-and lipid-lowering medication significantly diminished, but each of these was still necessary in 6.3% of the group. Correlation between body mass index and also calorie intake versus glucose and lipid measurements was highly significant (P = 0.000). CONCLUSIONS: 1) Energy intake after operation was very low; 2) Weight loss proceeded rapidly and correlated with meal pattern; 3) Improvement of glucose and lipid tests was adequate but took several quarters to normalize; 4) Decreased requirements for glucose- and lipid-lowering medication was significant but not absolute; 4) Fat percentage of total calories exceeded 30% at the end of the observation period, despite recommendations to the contrary.


Subject(s)
Blood Glucose/analysis , Gastric Bypass , Lipids/blood , Obesity, Morbid/blood , Obesity, Morbid/surgery , Adult , Female , Humans , Prospective Studies
9.
Int J Gynecol Cancer ; 16(3): 1283-8, 2006.
Article in English | MEDLINE | ID: mdl-16803518

ABSTRACT

This study was undertaken to evaluate the telomerase activity both in the tumor and in the vaginal margins of radical hysterectomy in patients with squamous cell carcinoma (SCC) of the cervix. Thirty-three patients with SCC of the cervix (study group) and 13 patients with uterine myoma (control group) were prospectively studied. Tissue samples were taken from the tumor or cervix, anterior vaginal margin (AVM), and posterior vaginal margin (PVM). The specimens were analyzed by histopathology, by a telomerase PCR-TRAP-ELISA kit, and by polymerase chain reaction using human papillomavirus (HPV) DNA. The telomerase activity was significantly higher in the tumor than in the benign cervix (P < 0.001). There was no difference in telomerase activity in the AVM and PVM in patients with cervical carcinoma compared to the control group. Telomerase activity was associated with the presence of histologic malignancy in the PVM of patients submitted to radical hysterectomy (P= 0.03). This association was not observed with the presence of HPV in AVM or PVM in the study group. Telomerase activity is a marker of histologic malignancy in patients with SCC of the cervix. There was no association between the telomerase activity and the presence of HPV in vaginal margins of patients submitted to radical hysterectomy.


Subject(s)
Carcinoma, Squamous Cell/enzymology , Hysterectomy , Neoplasm, Residual/diagnosis , Papillomaviridae/isolation & purification , Telomerase/metabolism , Uterine Cervical Neoplasms/surgery , Vagina/enzymology , Vaginal Neoplasms/enzymology , Vaginal Neoplasms/secondary , Adult , Aged , Biomarkers, Tumor/analysis , Carcinoma, Squamous Cell/surgery , Carcinoma, Squamous Cell/virology , DNA Probes, HPV , Female , Humans , Middle Aged , Polymerase Chain Reaction/methods , Vagina/pathology , Vagina/virology , Vaginal Neoplasms/virology
10.
Food Chem Toxicol ; 44(6): 877-84, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16442687

ABSTRACT

Ginger (Zingiber officinale Roscoe) has been proposed as a promising candidate for cancer prevention. Its modifying potential on the process of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) was investigated in male Wistar rats using the aberrant crypt foci (ACF) assay. Five groups were studied: Groups 1-3 were given four s.c. injections of DMH (40 mg/kg b.w.) twice a week, during two weeks, whereas Groups 4 and 5 received similar injections of EDTA solution (DMH vehicle). After DMH-initiation, the animals were fed a ginger extract mixed in the basal diet at 0.5% (Group 2) and 1.0% (Groups 3 and 4) for 10 weeks. All rats were killed after 12 weeks and the colons were analyzed for ACF formation and crypt multiplicity. The rates of cell proliferation and apoptosis were also evaluated in epithelial colonic crypt cells. Dietary consumption of ginger at both dose levels did not induce any toxicity in the rats, but ginger meal at 1% decreased significantly serum cholesterol levels (p<0.038). Treatment with ginger did not suppress ACF formation or the number of crypts per ACF in the DMH-treated group. Dietary ginger did not significantly change the proliferative or apoptosis indexes of the colonic crypt cells induced by DMH. Thus, the present results did not confirm a chemopreventive activity of ginger on colon carcinogenesis as analyzed by the ACF bioassay and by the growth kinetics of the colonic mucosa.


Subject(s)
Colonic Neoplasms/prevention & control , Plant Extracts/administration & dosage , Zingiber officinale/chemistry , 1,2-Dimethylhydrazine , Animals , Apoptosis/drug effects , Carcinogens , Cell Division/drug effects , Colon/pathology , Colonic Neoplasms/chemically induced , Colonic Neoplasms/pathology , Diet , Immunohistochemistry , Intestinal Mucosa/pathology , Male , Rats , Rats, Wistar
11.
Nutr Hosp ; 20(5): 320-5, 2005.
Article in English | MEDLINE | ID: mdl-16229399

ABSTRACT

Malnutrition is commonly associated with head and neck cancer, due especially to anorexia, which is aggravated by radiotherapy. The objective of this study was to evaluate modifications to nutritional ingestion following three types of nutritional intervention. Sixty-four male out-patients (62.1 +/- 1.5 years) were divided into three groups: oral group, (n=32) that received an adapted oral diet; feeding tube group, (n=16) under home enteral nutrition via a nasoenteral feeding tube (6x/day); and supplement group, (n=16) with oral diet associated to oral alimentary supplement between meals (3x/day). The groups were homogeneous and counseled to maintain a caloric ingestion of 40 kcal/kg. The diet for the oral group was adapted to the age and to the side effects of radiotherapyThe nutritional state of the three groups was evaluated for the caloric-proteic ingestion, anthropometric indicators (body weight, body mass index, triceps skinfold thickness, midarm muscle area), laboratorial indicators (total proteins, albumin, hematocrit, hemoglobin and total lymphocytes count), The results showed that all of the groups presented an increase in the ingestion of calories and proteins (p < 0.001). The nutritional therapy support for patients with head and neck cancer under radiotherapy, whether exclusive oral diet, enteral through a feeding tube, or with alimentary supplement associated to an oral diet achieved a significant increase in the total caloric ingestion. It is recommended that programs be implemented-to improve the ingestion of foods among these patients.


Subject(s)
Enteral Nutrition , Head and Neck Neoplasms/therapy , Nutrition Therapy , Administration, Oral , Body Mass Index , Data Interpretation, Statistical , Diet , Dietary Proteins/administration & dosage , Energy Intake , Head and Neck Neoplasms/radiotherapy , Humans , Male , Middle Aged , Nutritional Status , Prospective Studies , Radiotherapy/adverse effects , Radiotherapy Dosage
12.
Int J Food Microbiol ; 100(1-3): 125-30, 2005 Apr 15.
Article in English | MEDLINE | ID: mdl-15854698

ABSTRACT

Zygosaccharomyces bailii, a spoilage yeast, capable of metabolic activity in food environments with low pH, low a(w) and in the presence of weak acid preservatives was chosen for a study on the effect of benzoic acid on growth parameters. In batch cultures, under controlled pH, this food preservative inhibited growth, decreasing the specific growth rate (mu) and the yield coefficient (Y(S)) on glucose. Data obtained at pH 3.5, 4.0 and 4.5 showed that this inhibition was exclusively promoted by the undissociated form of the acid since the effect was independent of pH when the concentration of the acid was expressed in this form. Moreover, the relationship between the values for mu and Y(S), provided evidence that the specific consumption rate of glucose (q(S)) was not affected by benzoic acid, indicating that the inhibition of growth should be completely explained by a decrease of Y(S). The outcome of parallel experiments performed in continuous culture was that the decrease of Y(S) was due to an increase of the maintenance coefficient (m), defined as the fraction of q(S) diverted from growth to cope with stress, represented in this case by the presence of the preservative. Based on these results a model was built, assuming that m increased hyperbolically with the concentration of benzoic acid, from zero in the absence of the acid up to q(S) when growth was completely inhibited. The concentration of the acid, for which m=q(S)/2, is a constant (K(W)), and represents a measure of the tolerance for a preservative, in this case benzoic acid. The simple equation mu/mu(0)=1+W/K(W) predicts the value of mu for a concentration (W) of the preservative, requiring the knowledge of two parameters: the specific growth rate in the absence of the preservative (mu(0)) and K(W). The equation fitted very well the data of the effect of benzoic acid on the specific growth rate of Z. bailii, having K(W)=0.96 mM benzoic acid. The model was also validated with other spoilage yeasts grown in the presence of benzoic acid in microtiter plates in an automated spectrophotometer. The values obtained for K(W) under these conditions confirm Z. bailii as the most tolerant (K(W)=2.1 mM) followed by Pichia sp. (K(W)=0.78 mM), Saccharomyces cerevisiae (K(W)=0.53 mM) and Debaryomyces hansenii (K(W)=0.11 mM).


Subject(s)
Antifungal Agents/pharmacology , Benzoic Acid/pharmacology , Food Preservation/methods , Food Preservatives/pharmacology , Zygosaccharomyces/growth & development , Glucose/metabolism , Hydrogen-Ion Concentration , Mathematics , Models, Biological , Pichia/drug effects , Pichia/growth & development , Predictive Value of Tests , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/growth & development , Saccharomycetales/drug effects , Saccharomycetales/growth & development , Water/metabolism , Zygosaccharomyces/drug effects
13.
J Appl Microbiol ; 95(2): 364-71, 2003.
Article in English | MEDLINE | ID: mdl-12859770

ABSTRACT

AIMS: To investigate the conditions that promote the expression of cyanide-resistant respiration (CRR) in the spoilage yeasts Pichia membranifaciens and Debaryomyces hansenii. METHODS AND RESULTS: CRR was detected by sensitivity of oxygen consumption to salicylhydroxamic acid. It was absent in both yeasts in the early exponential phase, but was triggered by several stress situations. Starvation under aerobic conditions, decreasing pH or incubation of the culture in a narrow temperature range below the maximum temperature for growth promoted the emergence of CRR in both yeasts. In D. hansenii, CRR was also induced by 1.5-2 mol l(-1) NaCl. Although the presence of H2O2 and menadione induced CRR, radical scavengers had no effect on the emergence of CRR. Also, the level of reactive oxygen species did not vary with the CRR activity. CONCLUSIONS: Under aerobic conditions, a respiratory pathway alternative to the cytochrome chain is triggered by stress conditions in P. membranifaciens and D. hansenii. SIGNIFICANCE AND IMPACT OF THE STUDY: The relationship between stress situations and CRR must be taken into account in studies on the performance of spoilage yeasts in the food processing environments where several forms of stress are common.


Subject(s)
Food Microbiology , Oxygen Consumption/physiology , Potassium Cyanide/pharmacology , Yeasts/physiology , Antimycin A/pharmacology , Electron Transport/drug effects , Fermentation , Food Handling , Humans , Hydrogen-Ion Concentration , Mitochondrial Proteins , Oxidative Stress/physiology , Oxidoreductases/physiology , Oxygen Consumption/drug effects , Pichia/drug effects , Pichia/physiology , Plant Proteins , Temperature , Yeasts/drug effects
14.
FEMS Yeast Res ; 2(2): 93-102, 2002 May.
Article in English | MEDLINE | ID: mdl-12702297

ABSTRACT

The PKC1 gene in the yeast Saccharomyces cerevisiae encodes protein kinase C that is known to control a mitogen-activated protein (MAP) kinase cascade consisting of Bck1, Mkk1 and Mkk2, and Mpk1. This cascade affects the cell wall integrity but the phenotype of Pkc1 mutants suggests additional targets which have not yet been identified. We show that a pkc1Delta mutant, as opposed to mutants in the MAP kinase cascade, displays two major defects in the control of carbon metabolism. It shows a delay in the initiation of fermentation upon addition of glucose and a defect in derepression of SUC2 gene after exhaustion of glucose from the medium. After addition of glucose the production of both ethanol and glycerol started very slowly. The V(max) of glucose transport dropped considerably and Northern blot analysis showed that induction of the HXT1, HXT2 and HXT4 genes was strongly reduced. Growth of the pkc1Delta mutant was absent on glycerol and poor on galactose and raffinose. Oxygen uptake was barely present. Derepression of invertase activity and SUC2 transcription upon transfer of cells from glucose to raffinose was deficient in the pkc1Delta mutant as opposed to the wild-type. Our results suggest an involvement of Pkc1p in the control of carbon metabolism which is not shared by the downstream MAP kinase cascade.


Subject(s)
Glucose/metabolism , Glycoside Hydrolases/genetics , Protein Kinase C/physiology , Saccharomyces cerevisiae/enzymology , Transcription Factors/biosynthesis , Basic Helix-Loop-Helix Transcription Factors , Blotting, Northern , Gene Expression Regulation, Fungal , Mutation , Protein Kinase C/genetics , Repressor Proteins/metabolism , Saccharomyces cerevisiae/genetics , Signal Transduction/physiology , Transcription Factors/genetics , Transcription, Genetic , beta-Fructofuranosidase
15.
J Bacteriol ; 183(10): 3251-5, 2001 May.
Article in English | MEDLINE | ID: mdl-11325955

ABSTRACT

Two genes encoding Na(+)-ATPases from Debaryomyces hansenii were cloned and sequenced. The genes, designated ENA1 from D. hansenii (DhENA1) and DhENA2, exhibited high homology with the corresponding genes from Schwanniomyces occidentalis. DhENA1 was expressed in the presence of high Na(+) concentrations, while the expression of DhENA2 also required high pH. A mutant of Saccharomyces cerevisiae lacking the Na(+) efflux systems and sensitive to Na(+), when transformed with DhENA1 or DhENA2, recovered Na(+) tolerance and also the ability to extrude Na(+).


Subject(s)
Adenosine Triphosphatases/metabolism , Cation Transport Proteins , Cloning, Molecular , Saccharomyces cerevisiae Proteins , Saccharomycetales/genetics , Sodium Chloride/metabolism , Sodium-Potassium-Exchanging ATPase/metabolism , Adenosine Triphosphatases/genetics , Hydrogen-Ion Concentration , Molecular Sequence Data , Saccharomycetales/growth & development , Saccharomycetales/metabolism , Sodium-Potassium-Exchanging ATPase/genetics
16.
FEMS Microbiol Lett ; 190(1): 93-7, 2000 Sep 01.
Article in English | MEDLINE | ID: mdl-10981696

ABSTRACT

In Pichia membranifaciens, cyanide-resistant respiration (CRR) sensitive to salicylhydroxamic acid emerged after forced aeration of starved cells for 4 h. Surveying a large number of species by this simple methodology, we found that CRR is very frequent among yeasts. Remarkably, considering our results together with previous data in the literature, CRR was present in 24 out of 28 non-fermentative or Crabtree-negative yeasts and absent in 10 out of 12 Crabtree-positive yeasts. We submit that, as alternatives to cytochromic respiration, yeasts developed two strategies: either aerobic fermentation in Crabtree-positive yeasts or CRR in non-fermentative or Crabtree-negative yeasts.


Subject(s)
Oxygen Consumption/drug effects , Pichia/drug effects , Pichia/metabolism , Potassium Cyanide/pharmacology , Aerobiosis , Drug Resistance, Microbial , Fermentation , Pichia/growth & development , Salicylamides/pharmacology , Yeasts/metabolism
17.
Int J Food Microbiol ; 56(2-3): 191-7, 2000 Jun 01.
Article in English | MEDLINE | ID: mdl-10857545

ABSTRACT

The effect of Na+ and K+ on growth and thermal death of Debaryomyces hansenii and Saccharomyces cerevisiae were compared under stress conditions as those commonly found in food environments. At the supraoptimal temperature of 34 degrees C both cations at concentrations of 0.5 M stimulated growth of D. hansenii, while K+ had no effect and Na+ inhibited growth of S. cerevisiae. At 8 degrees C, close to the minimum temperature for growth in both species, both cations inhibited both yeasts, this effect being more pronounced with Na+ in S. cerevisiae. At extreme pH values (7.8 and 3.5) both cations at concentrations of 0.25 M stimulated D. hansenii while Na+ inhibited S. cerevisiae. K+ inhibited this yeast at pH 3.5. Thermal inactivation rates, measured at 38 degrees C in D. hansenii and at 48 degrees C in S. cerevisiae, decreased in the presence of both cations. This protective effect could be observed in a wider range of concentrations in D. hansenii. These results call the attention to the fact that not all yeasts have the same behaviour on what concerns synergy or antagonism of salt together with other stress factors and should be taken into consideration in the establishment of food preservation procedures.


Subject(s)
Potassium/pharmacology , Saccharomycetales/drug effects , Sodium/pharmacology , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/growth & development , Saccharomycetales/growth & development , Sorbitol/pharmacology , Temperature
18.
FEMS Microbiol Lett ; 184(1): 69-72, 2000 Mar 01.
Article in English | MEDLINE | ID: mdl-10689168

ABSTRACT

In batch cultures of a respiratory deficient mutant of Saccharomyces cerevisiae the maximum specific growth rate and the yield coefficient decreased, but the specific glucose consumption rate increased, in the presence of acetic acid. The ATP yield decreased from approximately 14 to 4 g biomass (mol ATP)(-1) when the concentration of acetic acid increased from 0 to 170 mM. Intracellular acidification was much weaker than previously reported for non-adapted cells. A linear relation was obtained between the ATP specific production rate and the uptake rate of acetic acid, suggesting that about 1 mol ATP is consumed per mol of acetic acid diffusing into the cells.


Subject(s)
Acetic Acid/pharmacology , Energy Metabolism/drug effects , Saccharomyces cerevisiae/drug effects , Cell Division/drug effects , Dose-Response Relationship, Drug , Ethanol/metabolism , Glucose/metabolism , Glycerol/metabolism , Hydrogen-Ion Concentration , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism
20.
Appl Environ Microbiol ; 63(10): 4005-9, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9327565

ABSTRACT

The effects of KCl, NaCl, and LiCl on the growth of Debaryomyces hansenii, usually considered a halotolerant yeast, and Saccharomyces cerevisiae were compared. KCl and NaCl had similar effects on D. hansenii, indicating that NaCl created only osmotic stress, while LiCl had a specific inhibitory effect, although relatively weaker than in S. cerevisiae. In media with low K+, Na+ was able to substitute for K+, restoring the specific growth rate and the final biomass of the culture. The intracellular concentration of Na+ reached values up to 800 mM, suggesting that metabolism is not affected by rather high concentrations of salt. The ability of D. hansenii to extrude Na+ and Li+ was similar to that described for S. cerevisiae, suggesting that this mechanism is not responsible for the increased halotolerance. Also, the kinetic parameters of Rb+ uptake in D. hansenii (Vmax, 4.2 nmol mg [dry weight]-1 min-1; K(m), 7.4 mM) indicate that the transport system was not more efficient than in S. cerevisiae. Sodium (50 mM) activated the transport of Rb+ by increasing the affinity for the substrate in D. hansenii, while the effect was opposite in S. cerevisiae. Lithium inhibited Rb+ uptake in D. hansenii. We propose that the metabolism of D. hansenii is less sensitive to intracellular Na+ than is that of S. cerevisiae, that Na+ substitutes for K+ when K+ is scarce, and that the transport of K+ is favored by the presence of Na+. In low K+ environments, D. hansenii behaved as a halophilic yeast.


Subject(s)
Saccharomycetales/drug effects , Saccharomycetales/physiology , Salts/pharmacology , Cations, Monovalent/pharmacology , Ion Transport/drug effects , Kinetics , Lithium Chloride/pharmacology , Osmotic Pressure , Potassium Chloride/pharmacology , Rubidium/pharmacokinetics , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/physiology , Saccharomycetales/growth & development , Sodium Chloride/pharmacology , Species Specificity
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