scholarly journals Comparative analysis of bacterial community composition in bulk tank raw milk by culture-dependent and culture-independent methods using the viability dye propidium monoazide

2014 ◽  
Vol 97 (11) ◽  
pp. 6761-6776 ◽  
Author(s):  
Mareike Weber ◽  
Janina Geißert ◽  
Myriam Kruse ◽  
André Lipski
Keyword(s):  
Comparative Analysis ◽  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
Raw Milk ◽  
Propidium Monoazide ◽  
Culture Independent ◽  
Bulk Tank ◽  
Culture Dependent

Effects of benthic macrofauna bioturbation on the bacterial community composition in lake sediments

2014 ◽  
Vol 60 (8) ◽  
pp. 517-524 ◽  
Author(s):  
Jin Zeng ◽  
Da-Yong Zhao ◽  
Peng Liu ◽  
Zhong-Bo Yu ◽  
Rui Huang ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Lake Taihu ◽  
Bacterial Community Composition ◽  
Chemical Properties ◽  
Eutrophic Lake ◽  
Benthic Macrofauna ◽  
Chironomidae Larvae ◽  
Culture Independent ◽  
Tubificid Worms

Benthic macrofauna are considered to be an important part of the lacustrine ecosystem, and bioturbation may greatly affect the biogeochemical processes and microbial activities in sediments. In the present study, the bacterial community composition in sediments inhabited by 3 different types of benthic macrofauna (Corbicula fluminea, Chironomidae larvae, and tubificid worms) in the shallow and eutrophic Lake Taihu was studied to investigate the different effects of bioturbation on the composition of these communities. Microcosms were constructed, and culture-independent methods, including terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis, were performed to evaluate the bacterial communities. Analysis of similarities (ANOSIM) and multidimensional scaling (MDS) analysis of T-RFLP patterns demonstrated that differences in the bacterial community composition between the control and the macrofauna-inhabited sediments were not as great as expected, although the chemical properties of the sediments changed remarkably. Nevertheless, the dominant bacterial group in each type of macrofauna-inhabited sediment was different. Acidobacteria, Betaproteobacteria, and Deltaproteobacteria were the dominant bacterial groups in sediments inhabited by C. fluminea, tubificid worms, and Chironomidae larvae, respectively. The data obtained in this study are helpful for understanding the effects of bioturbation in a shallow, eutrophic lake.

scholarly journals Geographic and Environmental Sources of Variation in Lake Bacterial Community Composition

2005 ◽  
Vol 71 (1) ◽  
pp. 227-239 ◽  
Author(s):  
Anthony C. Yannarell ◽  
Eric W. Triplett
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
Secchi Depth ◽  
Detection Threshold ◽  
Intergenic Spacer ◽  
Water Clarity ◽  
Culture Independent ◽  
Bacterial Assemblages ◽  
Landscape Level

ABSTRACT This study used a genetic fingerprinting technique (automated ribosomal intergenic spacer analysis [ARISA]) to characterize microbial communities from a culture-independent perspective and to identify those environmental factors that influence the diversity of bacterial assemblages in Wisconsin lakes. The relationships between bacterial community composition and 11 environmental variables for a suite of 30 lakes from northern and southern Wisconsin were explored by canonical correspondence analysis (CCA). In addition, the study assessed the influences of ARISA fragment detection threshold (sensitivity) and the quantitative, semiquantitative, and binary (presence-absence) use of ARISA data. It was determined that the sensitivity of ARISA was influential only when presence-absence-transformed data were used. The outcomes of analyses depended somewhat on the data transformation applied to ARISA data, but there were some features common to all of the CCA models. These commonalities indicated that differences in bacterial communities were best explained by regional (i.e., northern versus southern Wisconsin lakes) and landscape level (i.e., seepage lakes versus drainage lakes) factors. ARISA profiles from May samples were consistently different from those collected in other months. In addition, communities varied along gradients of pH and water clarity (Secchi depth) both within and among regions. The results demonstrate that environmental, temporal, regional, and landscape level features interact to determine the makeup of bacterial assemblages in northern temperate lakes.

scholarly journals Incorporation of Multi-Strain Probiotic Preparation in a Traditional Brazilian Cheese: Effects on Microbiological Safety and Bacterial Community

2019 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Moysés Estevão de S. F. Pehrson ◽  
Viviane Lívia C. Souza ◽  
Ismael M. Mancilha
Keyword(s):  
Bacterial Community ◽  
Consumer Preference ◽  
Raw Milk ◽  
Microbiological Safety ◽  
Off Flavors ◽  
Culture Independent ◽  
Probiotic Preparation ◽  
Raw Milk Cheese ◽  
Sensory Profiles ◽  
Culture Dependent

Consumer preference for raw milk cheeses has increased in the past few years. This occurred partly due to their more diverse, enjoyable characteristics, but also due to claims that certain members of the autochthonous microbiota of milk can be beneficial to human health. These microorganisms can inhibit the growth of undesirable microorganisms and may also be used to establish a biogeographic identity for these products. The aim of this study was to assess the effect of a multi-strain probiotic preparation on the microbiological safety and composition of bacterial community of a traditional Brazilian raw milk cheese by means of culture dependent and methods and pyrosequencing. Probiotic enriched cheeses presented an average of 50% less sequence reads belonging to Enterobacteriaceae than control cheeses. Total and thermotolerant coliforms cell viability decreased throughout ripening in two seasons (summer and autumn), while in the winter the presence of these microorganisms was negligible since the beginning of ripening. Results obtained through culture dependent method did not correlate with culture independent method, which pointed to a relatively constant number of Enterobacteriaceae reads during ripening. Viable cells of coagulase positive Staphylococcus aureus stayed within legal limits in both groups of cheeses since the first day and decreased to zero at the 15th day in probiotic enriched cheeses. Salmonella sp. and Listeria sp. were absent in both control and probiotic groups. Our results support that enriching raw milk cheeses with probiotic bacteria or other bioprotective bacteria may help mitigate off flavors produced by Enterobacteriaceae and result in safer products by inhibiting the growth of these microorganisms, while maintaining the microbial diversity that may be beneficial to sensory profiles and health-promoting characteristics. We also showed that this traditional cheese, if made under right the conditions, can meet legal parameters in much less than 60 days of ripening.

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