Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300016
Z. Porfírio, Micheline P. Ribeiro, Cicero S. Estevam, R. Houly, A. Sant'Ana
Cyanobacteria (Microcystis aeruginosa), which produce powerful hepatotoxic cyclopeptides, were collected and submitted to the determination of toxicity through intraperitoneal injections made in 30 and 90 days-old Swiss albino mice. The liver and the spleen were histopathologically analyzed and the weight and vital signs development were monitored. Test of toxicity resulted in a LD50 of 154.28 mg.Kg-1. M. aeruginosa represented 95% of the analyzed biomass. The ratios between liver weight and body weight in the animal inoculated with a single dose were 6.0% and 7.2%, with multi doses 7.0% and 7.5% and in the control animals 4.0% and 5.0%, for adult and young animals, respectively. There was an accentuated increase in the volume and weight of the spleen, and the animals inoculated with a single dose showed a ratio between spleen weight and body weight of 0.67% and 0.37%, with multidoses 1.22% and 1.05% and the control animals the ratio was 0.12% and 0.15%, for adult and young animals, respectively. The young animals inoculated with single and multi doses had an increase of 150% and 407% in the spleen size while the adults increased, 607% and 845%, respectively, in relation to the control. The histopathological analysis showed strong differences in the structure of the hepatic parenchyme in control animals and in those exposed to the M. aeruginosa extract. The main alterations were the congestive aspect, including the sinusoid, and intrahepatic haemorrhagia. The histopathological analysis showed considerable increase in the number of multinuclear giant cells in the spleen of the animals intoxicated by M. aeruginosa.
{"title":"Hepatosplenomegaly caused by an extract of cyanobacterium Microcystis aeruginosa bloom collected in the Manguaba Lagoon, Alagoas - Brazil","authors":"Z. Porfírio, Micheline P. Ribeiro, Cicero S. Estevam, R. Houly, A. Sant'Ana","doi":"10.1590/S0001-37141999000300016","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300016","url":null,"abstract":"Cyanobacteria (Microcystis aeruginosa), which produce powerful hepatotoxic cyclopeptides, were collected and submitted to the determination of toxicity through intraperitoneal injections made in 30 and 90 days-old Swiss albino mice. The liver and the spleen were histopathologically analyzed and the weight and vital signs development were monitored. Test of toxicity resulted in a LD50 of 154.28 mg.Kg-1. M. aeruginosa represented 95% of the analyzed biomass. The ratios between liver weight and body weight in the animal inoculated with a single dose were 6.0% and 7.2%, with multi doses 7.0% and 7.5% and in the control animals 4.0% and 5.0%, for adult and young animals, respectively. There was an accentuated increase in the volume and weight of the spleen, and the animals inoculated with a single dose showed a ratio between spleen weight and body weight of 0.67% and 0.37%, with multidoses 1.22% and 1.05% and the control animals the ratio was 0.12% and 0.15%, for adult and young animals, respectively. The young animals inoculated with single and multi doses had an increase of 150% and 407% in the spleen size while the adults increased, 607% and 845%, respectively, in relation to the control. The histopathological analysis showed strong differences in the structure of the hepatic parenchyme in control animals and in those exposed to the M. aeruginosa extract. The main alterations were the congestive aspect, including the sinusoid, and intrahepatic haemorrhagia. The histopathological analysis showed considerable increase in the number of multinuclear giant cells in the spleen of the animals intoxicated by M. aeruginosa.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"23 1","pages":"278-285"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84816852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300010
Elizabeth Teixeira, M. B. Serafim, M. A. D. C. Höfling, Á. Yamada, A. Castro
Uma amostra (S32) de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitoes. Esta amostra foi capaz de aderir a celulas HeLa mostrando um indice de adesao (AI) de 25,15 ± 1,26 (media ± 1 erro padrao da media). Tratamento das celulas bacterianas com tripsina (0,25mg/ml) diminuiu 70%-80% e metaperiodato (10mg/ml) aboliu significantemente a adesao, sugerindo que a estrutura responsavel por esta adesao era provavelmente uma glicoproteina. O tratamento pelo calor das suspensoes bacterianas (100oC/5min) diminuiu o AI ao nivel dos controles negativos. Soro de coelho anti-S32 inibiu a aderencia a celulas HeLa ate a diluicao de 1:640, pelo menos. O teste da alca ligada de leitao recem nascido demonstrou que a amostra S32 era capaz de aderir as celulas epiteliais intestinais, conforme demonstrado pela coloracao de Gram de seccoes histologicas do intestino dos animais inoculados. O estudo em Microscopio Eletronico de Transmissao demonstrou que a amostra S32 de Cl. perfringens mostrava um material de natureza fibrilar frouxa, ao contrario da amostra Jab-1 (controle negativo) que demonstrava uma aparencia "nua ou lisa". A estabilizacao das celulas bacterianas com antissoro homologo (S32), seguida de coloracao com vermelho de rutenio, revelou de maneira mais nitida que longos materiais fibrilares, de aparencia frouxa, se estendendo para longe da celula bacteriana, ligando por vezes estas celulas entre si. A possibilidade desta estrutura ser uma adesina para esta amostra de Cl. perfringens tipo A, talvez desempenhando um papel na patogenia da enterite catarral de leitoes, depende de mais estudos.
{"title":"Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis","authors":"Elizabeth Teixeira, M. B. Serafim, M. A. D. C. Höfling, Á. Yamada, A. Castro","doi":"10.1590/S0001-37141999000300010","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300010","url":null,"abstract":"Uma amostra (S32) de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitoes. Esta amostra foi capaz de aderir a celulas HeLa mostrando um indice de adesao (AI) de 25,15 ± 1,26 (media ± 1 erro padrao da media). Tratamento das celulas bacterianas com tripsina (0,25mg/ml) diminuiu 70%-80% e metaperiodato (10mg/ml) aboliu significantemente a adesao, sugerindo que a estrutura responsavel por esta adesao era provavelmente uma glicoproteina. O tratamento pelo calor das suspensoes bacterianas (100oC/5min) diminuiu o AI ao nivel dos controles negativos. Soro de coelho anti-S32 inibiu a aderencia a celulas HeLa ate a diluicao de 1:640, pelo menos. O teste da alca ligada de leitao recem nascido demonstrou que a amostra S32 era capaz de aderir as celulas epiteliais intestinais, conforme demonstrado pela coloracao de Gram de seccoes histologicas do intestino dos animais inoculados. O estudo em Microscopio Eletronico de Transmissao demonstrou que a amostra S32 de Cl. perfringens mostrava um material de natureza fibrilar frouxa, ao contrario da amostra Jab-1 (controle negativo) que demonstrava uma aparencia \"nua ou lisa\". A estabilizacao das celulas bacterianas com antissoro homologo (S32), seguida de coloracao com vermelho de rutenio, revelou de maneira mais nitida que longos materiais fibrilares, de aparencia frouxa, se estendendo para longe da celula bacteriana, ligando por vezes estas celulas entre si. A possibilidade desta estrutura ser uma adesina para esta amostra de Cl. perfringens tipo A, talvez desempenhando um papel na patogenia da enterite catarral de leitoes, depende de mais estudos.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"43 1","pages":"242-248"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73746264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300001
I. Beech, C. Gaylarde
Biocorrosion processes at metal surfaces are associated with microorganisms, or the products of their metabolic activities including enzymes, exopolymers, organic and inorganic acids, as well as volatile compounds such as ammonia or hydrogen sulfide. These can affect cathodic and/or anodic reactions, thus altering electrochemistry at the biofilm/metal interface. Various mechanisms of biocorrosion, reflecting the variety of physiological activities carried out by different types of microorganisms, are identified and recent insights into these mechanisms reviewed. Many modern investigations have centered on the microbially-influenced corrosion of ferrous and copper alloys and particular microorganisms of interest have been the sulfate-reducing bacteria and metal (especially manganese)-depositing bacteria. The importance of microbial consortia and the role of extracellular polymeric substances in biocorrosion are emphasized. The contribution to the study of biocorrosion of modern analytical techniques, such as atomic force microscopy, Auger electron, X-ray photoelectron and Mossbauer spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and microsensors, is discussed.
{"title":"Recent advances in the study of biocorrosion: an overview","authors":"I. Beech, C. Gaylarde","doi":"10.1590/S0001-37141999000300001","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300001","url":null,"abstract":"Biocorrosion processes at metal surfaces are associated with microorganisms, or the products of their metabolic activities including enzymes, exopolymers, organic and inorganic acids, as well as volatile compounds such as ammonia or hydrogen sulfide. These can affect cathodic and/or anodic reactions, thus altering electrochemistry at the biofilm/metal interface. Various mechanisms of biocorrosion, reflecting the variety of physiological activities carried out by different types of microorganisms, are identified and recent insights into these mechanisms reviewed. Many modern investigations have centered on the microbially-influenced corrosion of ferrous and copper alloys and particular microorganisms of interest have been the sulfate-reducing bacteria and metal (especially manganese)-depositing bacteria. The importance of microbial consortia and the role of extracellular polymeric substances in biocorrosion are emphasized. The contribution to the study of biocorrosion of modern analytical techniques, such as atomic force microscopy, Auger electron, X-ray photoelectron and Mossbauer spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and microsensors, is discussed.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"70 4 1","pages":"117-190"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77181521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300013
K. Nampoothiri, Ashok Pandey
Investigations were carried out with the aim of producing L-glutamic acid from Brevibacterium sp. by utilizing a locally available starchy substrate, cassava (Manihot esculenta Crantz). Initial studies were carried out in shake flasks, which showed that even though the yield was high with 85-90 DE (Dextrose Equivalent value), the maximum conversion yield (~34%) was obtained by using only partially digested starch hydrolysate, i.e. 45-50 DE. Fermentations were carried out in batch mode in a 5 L fermenter, using suitably diluted cassava starch hydrolysate, using a 85-90 DE value hydrolysate. Media supplemented with nutrients resulted in an accumulation of 21 g/L glutamic acid with a fairly high (66.3%) conversation yield of glucose to glutamic acid (based on glucose consumed and on 81.74% theoretical conversion rate). The bioreactor conditions most conducive for maximum production were pH 7.5, temperature 30°C and an agitation of 180 rpm. When fermentation was conducted in fed-batch mode by keeping the residual reducing sugar concentration at 5% w/v, 25.0 g/L of glutamate was obtained after 40 h fermentation (16% more the batch mode). Chromatographic separation by ion-exchange resin was used for the recovery and purification of glutamic acid. It was further crystallized and separated by making use of its low solubility at the isoelectric point (pH 3.2).
{"title":"Fermentation and recovery of L-glutamic acid from cassava starch hydrolysate by ion-exchange resin column","authors":"K. Nampoothiri, Ashok Pandey","doi":"10.1590/S0001-37141999000300013","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300013","url":null,"abstract":"Investigations were carried out with the aim of producing L-glutamic acid from Brevibacterium sp. by utilizing a locally available starchy substrate, cassava (Manihot esculenta Crantz). Initial studies were carried out in shake flasks, which showed that even though the yield was high with 85-90 DE (Dextrose Equivalent value), the maximum conversion yield (~34%) was obtained by using only partially digested starch hydrolysate, i.e. 45-50 DE. Fermentations were carried out in batch mode in a 5 L fermenter, using suitably diluted cassava starch hydrolysate, using a 85-90 DE value hydrolysate. Media supplemented with nutrients resulted in an accumulation of 21 g/L glutamic acid with a fairly high (66.3%) conversation yield of glucose to glutamic acid (based on glucose consumed and on 81.74% theoretical conversion rate). The bioreactor conditions most conducive for maximum production were pH 7.5, temperature 30°C and an agitation of 180 rpm. When fermentation was conducted in fed-batch mode by keeping the residual reducing sugar concentration at 5% w/v, 25.0 g/L of glutamate was obtained after 40 h fermentation (16% more the batch mode). Chromatographic separation by ion-exchange resin was used for the recovery and purification of glutamic acid. It was further crystallized and separated by making use of its low solubility at the isoelectric point (pH 3.2).","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"11 1","pages":"258-264"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87805657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300012
G. A. Soares, H. Sato
The strain Saccharomyces cerevisiae Y500-4L, previously selected from the must of alcohol producing plants and showing high fermentative and killer capacities, was characterized according to the interactions between the yeasts and examined for curing and detection of dsRNA plasmids, which code for the killer character. The killer yeast S. cerevisiae Y500-4L showed considerable killer activity against the Fleischmann and Itaiquara commercial brands of yeast and also against the standard killer yeasts K2 (S. diastaticus NCYC 713), K4 (Candida glabrata NCYC 388) and K11 (Torulopsis glabrata ATCC 15126). However S. cerevisiae Y500-4L showed sensitivity to the killer toxin produced by the standard killer yeasts K8 (Hansenula anomala NCYC 435), K9 (Hansenula mrakii NCYC 500), K10 (Kluyveromyces drosophilarum NCYC 575) and K11 (Torulopsis glabrata ATCC 15126). No M-dsRNA plasmid was detected in the S. cerevisiae Y500-4L strain and these results suggest that the genetic basis for toxin production is encoded by chromosomal DNA. The strain S. cerevisiae Y500-4L was more resistant to the loss of the phenotype killer with cycloheximide and incubation at elevated temperatures (40oC) than the standard killer yeast S. cerevisiae K1.
{"title":"Killer toxin of Saccharomyces cerevisiae Y500-4L active against Fleischmann and Itaiquara commercial brands of yeast","authors":"G. A. Soares, H. Sato","doi":"10.1590/S0001-37141999000300012","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300012","url":null,"abstract":"The strain Saccharomyces cerevisiae Y500-4L, previously selected from the must of alcohol producing plants and showing high fermentative and killer capacities, was characterized according to the interactions between the yeasts and examined for curing and detection of dsRNA plasmids, which code for the killer character. The killer yeast S. cerevisiae Y500-4L showed considerable killer activity against the Fleischmann and Itaiquara commercial brands of yeast and also against the standard killer yeasts K2 (S. diastaticus NCYC 713), K4 (Candida glabrata NCYC 388) and K11 (Torulopsis glabrata ATCC 15126). However S. cerevisiae Y500-4L showed sensitivity to the killer toxin produced by the standard killer yeasts K8 (Hansenula anomala NCYC 435), K9 (Hansenula mrakii NCYC 500), K10 (Kluyveromyces drosophilarum NCYC 575) and K11 (Torulopsis glabrata ATCC 15126). No M-dsRNA plasmid was detected in the S. cerevisiae Y500-4L strain and these results suggest that the genetic basis for toxin production is encoded by chromosomal DNA. The strain S. cerevisiae Y500-4L was more resistant to the loss of the phenotype killer with cycloheximide and incubation at elevated temperatures (40oC) than the standard killer yeast S. cerevisiae K1.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"29 1","pages":"253-257"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81000650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300002
S. P. Assis, R. Mariano, S. Michereff, Gil Silva, Elizabeth A. A. Maranhão
Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage cv. Midori were pulverized simultaneously with suspensions of antagonists and pathogen. After 10 days, plants were evaluated through percentage of foliar area with lesions. Percentage of disease severity reduction (DSR%) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79% of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T1=4 d before; T2=simultaneously; T3=4 d after; T4=4 d before + simultaneously; T5=4 d after + simultaneously; T6=4 d before + 4 d after; T7=4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71%), LR42 (67%), LR35 (69%) and LR19 (68%) in the treatments T7, T4, T5 and T6, which significantly differed from the others. The same yeast antagonists were also tested for black rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61%, and there was no significant difference among cultivars.
从白菜叶面中分离得到20株酵母菌，对其对油菜黄单胞菌的拮抗活性进行了评价。露营者，在野外。白菜属植物。与拮抗剂和病原菌混悬液同时粉碎。10 d后，通过叶损面积百分比对植株进行评价。还计算了疾病严重程度降低百分比(DSR%)。酵母菌分离株LR32、LR42和LR19的DSR分别为72%、75%和79%。这些拮抗剂在7个不同的应用时期进行了与病原体接种相关的试验(T1=4 d;同时T2 =;T3=4 d后;T4=4 d +同时;T5=4 d +同时;T6=4 d前+ 4 d后;T7=4天前+同时+ 4天后)。T7、T4、T5和T6处理中，LR42(71%)、LR42(67%)、LR35(69%)和LR19(68%)的dsr最高，与其他处理差异有统计学意义。同样的酵母拮抗剂也用不同的白菜品种(Fuyutoyo、Master-325、Matsukaze、Midori、Sekai I和Red Winner)进行了防治黑腐病的试验。dsr为58% ~ 61%，品种间差异不显著。
{"title":"ANTAGONISM OF YEASTS TO XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS ON CABBAGE PHYLLOPLANE IN FIELD","authors":"S. P. Assis, R. Mariano, S. Michereff, Gil Silva, Elizabeth A. A. Maranhão","doi":"10.1590/S0001-37141999000300002","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300002","url":null,"abstract":"Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage cv. Midori were pulverized simultaneously with suspensions of antagonists and pathogen. After 10 days, plants were evaluated through percentage of foliar area with lesions. Percentage of disease severity reduction (DSR%) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79% of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T1=4 d before; T2=simultaneously; T3=4 d after; T4=4 d before + simultaneously; T5=4 d after + simultaneously; T6=4 d before + 4 d after; T7=4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71%), LR42 (67%), LR35 (69%) and LR19 (68%) in the treatments T7, T4, T5 and T6, which significantly differed from the others. The same yeast antagonists were also tested for black rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61%, and there was no significant difference among cultivars.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"46 1","pages":"191-195"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87889223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300003
R. Fusconi, M. J. Godinho
The microbial populations of groundwaters were analyzed in a region under the influence of a landfill (piezometer L12) in the town of Sao Carlos, Sao Paulo, Brazil, and in an area not influenced by the landfill (piezometer L5). Heterotrophic bacteria were counted by spread plate method and the number of protozoa was estimated by the most probable number method. There was a larger number of organisms in well L12, with a mean value of 15.76 x 104 CFU/ml for bacteria and 9.7 MPN/ml for protozoa, whereas the mean values for piezometer L5 were 2.88 x 104 CFU/ml for bacteria and 3.4 MPN/ml for protozoa. The greater abundance detected in piezometer L12 may be related to the influence of the leachate through the landfill on the microbial populations, also demonstrated by deoxygenation and by the high conductivity values (3530 µS/cm) compared to piezometer L5 (2.47 mg/L dissolved oxygen and 42 µS/cm conductivity). The most commonly detected protozoa were amoebae and flagellates. The density of flagellate protozoa determined under microaerophilic conditions was 10 times higher than that determined under aerobic conditions.
{"title":"Bacteria and protozoa populations in groundwater in landfill area in São Carlos, SP","authors":"R. Fusconi, M. J. Godinho","doi":"10.1590/S0001-37141999000300003","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300003","url":null,"abstract":"The microbial populations of groundwaters were analyzed in a region under the influence of a landfill (piezometer L12) in the town of Sao Carlos, Sao Paulo, Brazil, and in an area not influenced by the landfill (piezometer L5). Heterotrophic bacteria were counted by spread plate method and the number of protozoa was estimated by the most probable number method. There was a larger number of organisms in well L12, with a mean value of 15.76 x 104 CFU/ml for bacteria and 9.7 MPN/ml for protozoa, whereas the mean values for piezometer L5 were 2.88 x 104 CFU/ml for bacteria and 3.4 MPN/ml for protozoa. The greater abundance detected in piezometer L12 may be related to the influence of the leachate through the landfill on the microbial populations, also demonstrated by deoxygenation and by the high conductivity values (3530 µS/cm) compared to piezometer L5 (2.47 mg/L dissolved oxygen and 42 µS/cm conductivity). The most commonly detected protozoa were amoebae and flagellates. The density of flagellate protozoa determined under microaerophilic conditions was 10 times higher than that determined under aerobic conditions.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"9 1","pages":"196-202"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87230111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300015
S. Saad, B. Franco
Escherichia coli O157:H7 e um patogeno de origem alimentar de importância crescente, tendo sido envolvido em diversos surtos ameacadores, a maioria deles associada ao consumo de produtos carneos. Neste estudo foi avaliada a influencia de algumas bacterias da microbiota natural da carne crua sobre E. coli O157:H7 em amostras de carne bovina moida armazenadas em refrigeracao e a temperatura ambiente. As amostras foram inoculadas com diferentes niveis de E. coli O157:H7 (101, 103 e 106 UFC/g) e de E. coli nao patogenica, Pseudomonas putida ou Leuconostoc sp. A multiplicacao do patogeno foi monitorada atraves de metodologia convencional e atraves de metodo rapido do tipo ELISA. E. coli nao patogenica, Pseudomonas putida e Leuconostoc sp. nao exerceram influencia sobre a multiplicacao de E. coli O157:H7 em carne moida, tanto em refrigeracao como a temperatura ambiente. Assim sendo, a baixa ocorrencia de E. coli O157:H7 em carne crua nao pode ser atribuida a efeitos antagonicos de bacterias de sua microbiota natural.
{"title":"Influence of raw meat natural background flora on growth of Escherichia coli O157: H7 in ground beef","authors":"S. Saad, B. Franco","doi":"10.1590/S0001-37141999000300015","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300015","url":null,"abstract":"Escherichia coli O157:H7 e um patogeno de origem alimentar de importância crescente, tendo sido envolvido em diversos surtos ameacadores, a maioria deles associada ao consumo de produtos carneos. Neste estudo foi avaliada a influencia de algumas bacterias da microbiota natural da carne crua sobre E. coli O157:H7 em amostras de carne bovina moida armazenadas em refrigeracao e a temperatura ambiente. As amostras foram inoculadas com diferentes niveis de E. coli O157:H7 (101, 103 e 106 UFC/g) e de E. coli nao patogenica, Pseudomonas putida ou Leuconostoc sp. A multiplicacao do patogeno foi monitorada atraves de metodologia convencional e atraves de metodo rapido do tipo ELISA. E. coli nao patogenica, Pseudomonas putida e Leuconostoc sp. nao exerceram influencia sobre a multiplicacao de E. coli O157:H7 em carne moida, tanto em refrigeracao como a temperatura ambiente. Assim sendo, a baixa ocorrencia de E. coli O157:H7 em carne crua nao pode ser atribuida a efeitos antagonicos de bacterias de sua microbiota natural.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"68 1","pages":"272-277"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79118315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300006
T. Lima, B. Grisi, M. Bonato
In this investigation, a sugarcane agroecosystem at a coastal tableland, in the northeast of Brazil, was screened to obtain bacteria strains able to synthesize poly-b-hydroxyalkanoates (PHA), using sucrose as the main carbon source. The potential to synthesize PHA was tested qualitatively by Sudan Black staining of colonies growing in different carbon sources: sucrose, glucose, fructose, propionate and cellulose. In a typical sugarcane crop management system, the plantation is burned before harvesting and vinasse, a byproduct of alcohol production, is used in a fertirrigation system causing, probably, selective pressures on the microbiota of natural environments. Eightytwo bacteria strains, belonging to 16 different genera and 35 different species, were isolated. The data showed that 11 strains (ca 13%), nine of which belonging to the genus Pseudomonas, presented a strong Sudan Black staining in several carbon sources tested and, simultaneously, showed multiple resistance to antibiotics. Resistance to antibiotics is an advantageous feature for the biotechnological production of PHAs. The total number of isolates with multiple resistance to antibiotics was 73, and 38% of them belong to the genus Pseudomonas. Among the isolates, ca 86% and 43% grew in the presence of 10-100 U/ml of penicillin and/or 100-300 mg/ml of virginiamycin, respectively. These antibiotics are utilized in the alcohol distillery we investigated. The results suggest that some agroecosystem environments could be considered as habitats where bacteria are submitted to nutritional unbalanced conditions, resulting in strains with potential ability to produce PHAs, and also, to an increase in the microbial diversity.
{"title":"Bacteria isolated from a sugarcane agroecosystem: their potential production of polyhydroxyalcanoates and resistance to antibiotics","authors":"T. Lima, B. Grisi, M. Bonato","doi":"10.1590/S0001-37141999000300006","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300006","url":null,"abstract":"In this investigation, a sugarcane agroecosystem at a coastal tableland, in the northeast of Brazil, was screened to obtain bacteria strains able to synthesize poly-b-hydroxyalkanoates (PHA), using sucrose as the main carbon source. The potential to synthesize PHA was tested qualitatively by Sudan Black staining of colonies growing in different carbon sources: sucrose, glucose, fructose, propionate and cellulose. In a typical sugarcane crop management system, the plantation is burned before harvesting and vinasse, a byproduct of alcohol production, is used in a fertirrigation system causing, probably, selective pressures on the microbiota of natural environments. Eightytwo bacteria strains, belonging to 16 different genera and 35 different species, were isolated. The data showed that 11 strains (ca 13%), nine of which belonging to the genus Pseudomonas, presented a strong Sudan Black staining in several carbon sources tested and, simultaneously, showed multiple resistance to antibiotics. Resistance to antibiotics is an advantageous feature for the biotechnological production of PHAs. The total number of isolates with multiple resistance to antibiotics was 73, and 38% of them belong to the genus Pseudomonas. Among the isolates, ca 86% and 43% grew in the presence of 10-100 U/ml of penicillin and/or 100-300 mg/ml of virginiamycin, respectively. These antibiotics are utilized in the alcohol distillery we investigated. The results suggest that some agroecosystem environments could be considered as habitats where bacteria are submitted to nutritional unbalanced conditions, resulting in strains with potential ability to produce PHAs, and also, to an increase in the microbial diversity.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"6 1","pages":"214-224"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79343822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-07-01DOI: 10.1590/S0001-37141999000300008
F. Bicca, L. Fleck, M. Ayub
There is world wide concern about the liberation of hydrocarbons in the environment, both from industrial activities and from accidental spills of oil and oilrelated compounds. Biosurfactants, which are natural emulsifiers of hydrocarbons, are produced by some bacteria, fungi and yeast. They are polymers, totally or partially extracellular, with an amphipathyc structure, which allows them to form micelles that accumulate at the interface between liquids of different polarities such as water and oil. This process is based upon the ability of biosurfactants to reduce surface tension, blocking the formation of hydrogen bridges and certain hydrophilic and hydrophobic interactions. The ability of biosurfactant production by five strains of Rhodococcus isolated from oil prospecting sites was evaluated. Surface tension measurement and emulsifying index were used to quantify biosurfactant production. The influence of environmental conditions was also investigated - pH, temperature, medium composition, and type of carbon source - on cell growth and biosurfactant production. Strain AC 239 was shown to be a potential producer, attaining 63% of emulsifying index for a Diesel-water binary system. It could be used, either directly on oil spills in contained environments, or for the biotechnological production of biosurfactant.
{"title":"Production of biosurfactant by hydrocarbon degrading Rhodococcus ruber and Rhodococcus erythropolis","authors":"F. Bicca, L. Fleck, M. Ayub","doi":"10.1590/S0001-37141999000300008","DOIUrl":"https://doi.org/10.1590/S0001-37141999000300008","url":null,"abstract":"There is world wide concern about the liberation of hydrocarbons in the environment, both from industrial activities and from accidental spills of oil and oilrelated compounds. Biosurfactants, which are natural emulsifiers of hydrocarbons, are produced by some bacteria, fungi and yeast. They are polymers, totally or partially extracellular, with an amphipathyc structure, which allows them to form micelles that accumulate at the interface between liquids of different polarities such as water and oil. This process is based upon the ability of biosurfactants to reduce surface tension, blocking the formation of hydrogen bridges and certain hydrophilic and hydrophobic interactions. The ability of biosurfactant production by five strains of Rhodococcus isolated from oil prospecting sites was evaluated. Surface tension measurement and emulsifying index were used to quantify biosurfactant production. The influence of environmental conditions was also investigated - pH, temperature, medium composition, and type of carbon source - on cell growth and biosurfactant production. Strain AC 239 was shown to be a potential producer, attaining 63% of emulsifying index for a Diesel-water binary system. It could be used, either directly on oil spills in contained environments, or for the biotechnological production of biosurfactant.","PeriodicalId":21211,"journal":{"name":"Revista De Microbiologia","volume":"201 1","pages":"231-236"},"PeriodicalIF":0.0,"publicationDate":"1999-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77683854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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