scholarly journals Microbiota Dynamics and Diversity at Different Stages of Industrial Processing of Cocoa Beans into Cocoa Powder

2012 ◽  
Vol 78 (8) ◽  
pp. 2904-2913 ◽  
Author(s):  
Lídia J. R. Lima ◽  
Vera van der Velpen ◽  
Judith Wolkers-Rooijackers ◽  
Henri J. Kamphuis ◽  
Marcel H. Zwietering ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Rrna Gene ◽  
Cocoa Beans ◽  
Community Size ◽  
Cocoa Powder ◽  
Content Type ◽  
Industrial Processing ◽  
Microbiological Methods ◽  
Gradient Gel Electrophoresis ◽  
The Impact

ABSTRACTWe sampled a cocoa powder production line to investigate the impact of processing on the microbial community size and diversity at different stages. Classical microbiological methods were combined with 16S rRNA gene PCR-denaturing gradient gel electrophoresis, coupled with clone library construction, to analyze the samples. Aerobic thermoresistant spores (ThrS) (100°C; 10 min) were also isolated and characterized (identity, genetic diversity, and spore heat resistance), in view of their relevance to the quality of downstream heat-treated cocoa-flavored drinks. In the nibs (broken, shelled cocoa beans), average levels of total aerobic microorganisms (TAM) (4.4 to 5.6 log CFU/g) and aerobic total spores (TS) (80°C; 10 min; 4.3 to 5.5 log CFU/g) were significantly reduced (P< 0.05) as a result of alkalizing, while fungi (4.2 to 4.4 log CFU/g) andEnterobacteriaceae(1.7 to 2.8 log CFU/g) were inactivated to levels below the detection limit, remaining undetectable throughout processing. Roasting further decreased the levels of TAM and TS, but they increased slightly during subsequent processing. Molecular characterization of bacterial communities based on enriched cocoa samples revealed a predominance of members of theBacillaceae,Pseudomonadaceae, andEnterococcaceae. Eleven species of ThrS were found, butBacillus licheniformisand theBacillus subtiliscomplex were prominent and revealed great genetic heterogeneity. We concluded that the microbiota of cocoa powder resulted from microorganisms that could have been initially present in the nibs, as well as microorganisms that originated during processing.B. subtiliscomplex members, particularlyB. subtilissubsp.subtilis, formed the most heat-resistant spores. Their occurrence in cocoa powder needs to be considered to ensure the stability of derived products, such as ultrahigh-temperature-treated chocolate drinks.

scholarly journals Molecular Analysis of Surfactant-Driven Microbial Population Shifts in Hydrocarbon-Contaminated Soil

2000 ◽  
Vol 66 (7) ◽  
pp. 2959-2964 ◽  
Author(s):  
Gregory M. Colores ◽  
Richard E. Macur ◽  
David M. Ward ◽  
William P. Inskeep
Keyword(s):  
Gel Electrophoresis ◽  
Microbial Population ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Populations ◽  
Alcohol Ethoxylate ◽  
Rrna Gene ◽  
Mineralization Kinetics ◽  
Gradient Gel Electrophoresis ◽  
The Impact ◽  
Parallel Cultivation

ABSTRACT We analyzed the impact of surfactant addition on hydrocarbon mineralization kinetics and the associated population shifts of hydrocarbon-degrading microorganisms in soil. A mixture of radiolabeled hexadecane and phenanthrene was added to batch soil vessels. Witconol SN70 (a nonionic, alcohol ethoxylate) was added in concentrations that bracketed the critical micelle concentration (CMC) in soil (CMC′) (determined to be 13 mg g−1). Addition of the surfactant at a concentration below the CMC′ (2 mg g−1) did not affect the mineralization rates of either hydrocarbon. However, when surfactant was added at a concentration approaching the CMC′ (10 mg g−1), hexadecane mineralization was delayed and phenanthrene mineralization was completely inhibited. Addition of surfactant at concentrations above the CMC′ (40 mg g−1) completely inhibited mineralization of both phenanthrene and hexadecane. Denaturing gradient gel electrophoresis of 16S rRNA gene segments showed that hydrocarbon amendment stimulatedRhodococcus and Nocardia populations that were displaced by Pseudomonas and Alcaligenespopulations at elevated surfactant levels. Parallel cultivation studies revealed that the Rhodococcus population can utilize hexadecane and that the Pseudomonas andAlcaligenes populations can utilize both Witconol SN70 and hexadecane for growth. The results suggest that surfactant applications necessary to achieve the CMC alter the microbial populations responsible for hydrocarbon mineralization.

scholarly journals Efficacy of Rifaximin Vaginal Tablets in Treatment of Bacterial Vaginosis: a Molecular Characterization of the Vaginal Microbiota

2012 ◽  
Vol 56 (8) ◽  
pp. 4062-4070 ◽  
Author(s):  
Federica Cruciani ◽  
Patrizia Brigidi ◽  
Fiorella Calanni ◽  
Vittoria Lauro ◽  
Raffaella Tacchi ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Vaginal Microbiota ◽  
Controlled Study ◽  
Double Blind ◽  
Content Type ◽  
Sexually Transmitted ◽  
Gradient Gel Electrophoresis ◽  
Adverse Pregnancy ◽  
The Impact

ABSTRACTBacterial vaginosis (BV) is a common vaginal disorder characterized by an alteration of the vaginal bacterial morphotypes, associated with sexually transmitted infections and adverse pregnancy outcomes. The purpose of the present study was to evaluate the impact of different doses of rifaximin vaginal tablets (100 mg/day for 5 days, 25 mg/day for 5 days, and 100 mg/day for 2 days) on the vaginal microbiota of 102 European patients with BV enrolled in a multicenter, double-blind, randomized, placebo-controlled study. An integrated molecular approach based on quantitative PCR (qPCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) was used to investigate the effects of vaginal tablets containing the antibiotic. An increase in members of the genusLactobacillusand a decrease in the BV-related bacterial groups after the antibiotic treatment were demonstrated by qPCR. PCR-DGGE profiles confirmed the capability of rifaximin to modulate the composition of the vaginal microbial communities and to reduce their complexity. This molecular analysis supported the clinical observation that rifaximin at 25 mg/day for 5 days represents an effective treatment to be used in future pivotal studies for the treatment of BV.

scholarly journals Microbial Ecology Dynamics during Rye and Wheat Sourdough Preparation

2013 ◽  
Vol 79 (24) ◽  
pp. 7827-7836 ◽  
Author(s):  
Danilo Ercolini ◽  
Erica Pontonio ◽  
Francesca De Filippis ◽  
Fabio Minervini ◽  
Antonietta La Storia ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbial Ecology ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Diversity Indices ◽  
Rrna Gene ◽  
Content Type ◽  
Gradient Gel Electrophoresis ◽  
Plate Counts ◽  
Relative Abundances

ABSTRACTThe bacterial ecology during rye and wheat sourdough preparation was described by 16S rRNA gene pyrosequencing. Viable plate counts of presumptive lactic acid bacteria, the ratio between lactic acid bacteria and yeasts, the rate of acidification, a permutation analysis based on biochemical and microbial features, the number of operational taxonomic units (OTUs), and diversity indices all together demonstrated the maturity of the sourdoughs during 5 to 7 days of propagation. Flours were mainly contaminated by metabolically active genera (Acinetobacter,Pantoea,Pseudomonas,Comamonas,Enterobacter,Erwinia, andSphingomonas) belonging to the phylumProteobacteriaorBacteroidetes(genusChryseobacterium). Their relative abundances varied with the flour. Soon after 1 day of propagation, this population was almost completely inhibited except for theEnterobacteriaceae. Although members of the phylumFirmicuteswere present at very low or intermediate relative abundances in the flours, they became dominant soon after 1 day of propagation. Lactic acid bacteria were almost exclusively representative of theFirmicutesby this time.Weissellaspp. were already dominant in rye flour and stably persisted, though they were later flanked by theLactobacillus sakeigroup. There was a succession of species during 10 days of propagation of wheat sourdoughs. The fluctuation between dominating and subdominating populations ofL. sakeigroup,Leuconostocspp.,Weissellaspp., andLactococcus lactiswas demonstrated. Other subdominant species such asLactobacillus plantarumwere detectable throughout propagation. As shown by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis,Saccharomyces cerevisiaedominated throughout the sourdough propagation. Notwithstanding variations due to environmental and technology determinants, the results of this study represent a clear example of how the microbial ecology evolves during sourdough preparation.

scholarly journals Bacterial Chitinolytic Communities Respond to Chitin and pH Alteration in Soil

2012 ◽  
Vol 79 (1) ◽  
pp. 263-272 ◽  
Author(s):  
Anna M. Kielak ◽  
Mariana Silvia Cretoiu ◽  
Alexander V. Semenov ◽  
Søren J. Sørensen ◽  
Jan Dirk van Elsas
Keyword(s):  
16S Rrna ◽  
Bacterial Communities ◽  
Plant Pathogens ◽  
Structural Changes ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Acid Soil ◽  
Rrna Gene ◽  
Content Type ◽  
Soil Suppressiveness ◽  
Gradient Gel Electrophoresis

ABSTRACTChitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA andchiAgenes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity ofchiAgene types in soil is enormous and (i) that differentchiAgene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one ofActinobacteriain the immediate response to the added chitin (based on 16S rRNA gene abundance andchiAgene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.

scholarly journals Changes in Bacterial Diversity Associated with Epithelial Tissue in the Beef Cow Rumen during the Transition to a High-Grain Diet

2011 ◽  
Vol 77 (16) ◽  
pp. 5770-5781 ◽  
Author(s):  
Yanhong Chen ◽  
Gregory B. Penner ◽  
Meiju Li ◽  
Masahito Oba ◽  
Le Luo Guan
Keyword(s):  
Bacterial Diversity ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pcr Analysis ◽  
Control Group ◽  
Epithelial Tissue ◽  
Rrna Gene ◽  
Content Type ◽  
Beef Cow ◽  
Dietary Transition ◽  
Gradient Gel Electrophoresis

ABSTRACTOur understanding of the ruminal epithelial tissue-associated bacterial (defined as epimural bacteria in this study) community is limited. In this study, we aimed to determine whether diet influences the diversity of the epimural bacterial community in the bovine rumen. Twenty-four beef heifers were randomly assigned to either a rapid grain adaptation (RGA) treatment (n= 18) in which the heifers were allowed to adapt from a diet containing 97% hay to a diet containing 8% hay over 29 days or to the control group (n= 6), which was fed 97% hay. Rumen papillae were collected when the heifers were fed 97%, 25%, and 8% hay diets. PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR analysis were used to characterize rumen epimural bacterial diversity and to estimate the total epimural bacterial population (copy numbers of the 16S rRNA gene). The epimural bacterial diversity from RGA heifers changed (P= 0.01) in response to the rapid dietary transition, whereas it was not affected in control heifers. A total of 88 PCR-DGGE bands were detected, and 44 were identified from phyla includingFirmicutes,Bacteroidetes, andProteobacteria. The bacteriaTreponemasp.,Ruminobactersp., andLachnospiraceaesp. were detected only when heifers were fed 25% and 8% hay diets, suggesting the presence of these bacteria is the result of adaptation to the high-grain diets. In addition, the total estimated population of rumen epimural bacteria was positively correlated with molar proportions of acetate, isobutyrate, and isovalerate, suggesting that they may play a role in volatile fatty acid metabolism in the rumen.

scholarly journals Evaluation of a Parchment Document, the 13th Century Incorporation Charter for the City of Krakow, Poland, for Microbial Hazards

2016 ◽  
Vol 82 (9) ◽  
pp. 2620-2631 ◽  
Author(s):  
Tomasz Lech
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Genetic Identification ◽  
13Th Century ◽  
Content Type ◽  
Microbiological Methods ◽  
Gradient Gel Electrophoresis ◽  
Identification Of Bacteria ◽  
Bacteria And Fungi ◽  
The City ◽  
Destructive Potential

ABSTRACTThe literature of environmental microbiology broadly discusses issues associated with microbial hazards in archives, but these publications are mainly devoted to paper documents. There are few articles on historical parchment documents, which used to be very important for the development of literature and the art of writing. These studies present a broad spectrum of methods for the assessment of biodeterioration hazards of the parchment document in question. They are based on both conventional microbiological methods and advanced techniques of molecular biology. Here, a qualitative analysis was conducted, based on genetic identification of bacteria and fungi present on the document as well as denaturing gradient gel electrophoresis profiling and examining the destructive potential of isolated microbes. Moreover, the study involved a quantitative and qualitative microbiological assessment of the indoor air in the room where the parchment was kept. The microbes with the highest destructive potential that were isolated from the investigated item wereBacillus cereusandAcinetobacter lwoffiibacteria andPenicillium chrysogenum,Chaetomium globosum, andTrichoderma longibrachiatumfungi. The presence of theB. cereusstrain was particularly interesting since, under appropriate conditions, it leads to complete parchment degradation within several days.

scholarly journals Biodiversity in Oscypek, a Traditional Polish Cheese, Determined by Culture-Dependent and -Independent Approaches

2012 ◽  
Vol 78 (6) ◽  
pp. 1890-1898 ◽  
Author(s):  
Ángel Alegría ◽  
Pawel Szczesny ◽  
Baltasar Mayo ◽  
Jacek Bardowski ◽  
Magdalena Kowalczyk
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Starter Cultures ◽  
Rrna Gene ◽  
Content Type ◽  
Protected Designation Of Origin ◽  
Culture Independent ◽  
Gradient Gel Electrophoresis ◽  
Microbial Groups ◽  
The Tatra Mountains ◽  
Culture Dependent

ABSTRACTOscypek is a traditional Polish scalded-smoked cheese, with a protected-designation-of-origin (PDO) status, manufactured from raw sheep's milk without starter cultures in the Tatra Mountains region of Poland. This study was undertaken in order to gain insight into the microbiota that develops and evolves during the manufacture and ripening stages of Oscypek. To this end, we made use of both culturing and the culture-independent methods of PCR followed by denaturing gradient gel electrophoresis (PCR-DGGE) and pyrosequencing of 16S rRNA gene amplicons. The culture-dependent technique and PCR-DGGE fingerprinting detected the predominant microorganisms in traditional Oscypek, whereas the next-generation sequencing technique (454 pyrosequencing) revealed greater bacterial diversity. Besides members of the most abundant bacterial genera in dairy products, e.g.,Lactococcus,Lactobacillus,Leuconostoc,Streptococcus, andEnterococcus, identified by all three methods, other, subdominant bacteria belonging to the familiesBifidobacteriaceaeandMoraxellaceae(mostlyEnhydrobacter), as well as various minor bacteria, were identified by pyrosequencing. The presence of bifidobacterial sequences in a cheese system is reported for the first time. In addition to bacteria, a great diversity of yeast species was demonstrated in Oscypek by the PCR-DGGE method. Culturing methods enabled the determination of a number of viable microorganisms from different microbial groups and their isolation for potential future applications in specific cheese starter cultures.

scholarly journals Culture-Independent Analysis of Bacterial Fuel Contamination Provides Insight into the Level of Concordance with the Standard Industry Practice of Aerobic Cultivation

2011 ◽  
Vol 77 (13) ◽  
pp. 4527-4538 ◽  
Author(s):  
Judith White ◽  
Jack Gilbert ◽  
Graham Hill ◽  
Edward Hill ◽  
Susan M. Huse ◽  
...  
Keyword(s):  
16S Rrna ◽  
Denaturing Gradient Gel Electrophoresis ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Content Type ◽  
Aerobic Culture ◽  
Aerobic Cultivation ◽  
Culture Independent ◽  
Gradient Gel Electrophoresis ◽  
Industry Practice

ABSTRACTBacterial diversity in contaminated fuels has not been systematically investigated using cultivation-independent methods. The fuel industry relies on phenotypic cultivation-based contaminant identification, which may lack accuracy and neglect difficult-to-culture taxa. By the use of industry practice aerobic cultivation, 16S rRNA gene sequencing, and strain genotyping, a collection of 152 unique contaminant isolates from 54 fuel samples was assembled, and a dominance ofPseudomonas(21%),Burkholderia(7%), andBacillus(7%) was demonstrated. Denaturing gradient gel electrophoresis (DGGE) of 15 samples revealedProteobacteriaandFirmicutesto be the most abundant phyla. When 16S rRNA V6 gene pyrosequencing of four selected fuel samples (indicated by “JW”) was performed,Betaproteobacteria(42.8%) andGammaproteobacteria(30.6%) formed the largest proportion of reads; the most abundant genera wereMarinobacter(15.4%; JW57),Achromobacter(41.6%; JW63),Burkholderia(80.7%; JW76), andHalomonas(66.2%; JW78), all of which were also observed by DGGE. However, theClostridia(38.5%) andDeltaproteobacteria(11.1%) identified by pyrosequencing in sample JW57 were not observed by DGGE or aerobic culture. Genotyping revealed three instances where identical strains were found: (i) aPseudomonassp. strain recovered from 2 different diesel fuel tanks at a single industrial site; (ii) aMangroveibactersp. strain isolated from 3 biodiesel tanks at a single refinery site; and (iii) aBurkholderiavietnamiensisstrain present in two unrelated automotive diesel samples. Overall, aerobic cultivation of fuel contaminants recovered isolates broadly representative of the phyla and classes present but lacked accuracy by overrepresenting members of certain groups such asPseudomonas.

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