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Jaguariúna, Brazil

News Article | April 15, 2016
Site: http://www.rdmag.com/rss-feeds/all/rss.xml/all

Nursing infants' gastrointestinal tracts are enriched with specific protective microbes. Mother's milk, itself, guides the development of neonates' gut microbiota, nourishing a very specific bacterial population that, in turn, provides nourishment and protects the child. Now a team from the University of California, Davis, has identified the compound in the milk that supplies this nourishment, and has shown that it can be obtained from cow's milk. This work could result in using cow's milk to provide that compound as a prebiotic for infants. The research is published ahead of print on April 15th in Applied and Environmental Microbiology, a journal of the American Society for Microbiology. In earlier research, these investigators, led by David A. Mills, PhD, had shown that glycoproteins from milk, which contain both protein, and molecules containing multiple sugars, called oligosaccharides, were the source of that nourishment. They also had found that the infant-associated subspecies of the bacterium, Bifidobacterium longum subsp. infantis (B. infantis), produced an enzyme that could cleave the oligosaccharides from the milk glycoproteins, and they had identified that enzyme. For the current study, Mills, who is Professor and Shields Endowed Chair in Dairy Food Science, and his collaborators posited that these oligosaccharides were the food source for B. infantis. They then showed that the enzyme could break down glycoproteins not only from mother's milk, but from cow's milk, releasing the oligosaccharides. "The released oligosaccharides turned out to be an incredible substrate for B. infantis' growth," said Mills. At the same time, Mills et al. showed that the oligosaccharides did not nourish adult-associated bifidobacteria. All that suggests that getting the bioactive oligosaccharides into infant formula could improve it, said Mills. But his emphasis is on the science, he said. "The amazing thing to me is how selective these released oligosaccharides are as a substrate for growth." Mills noted that B. infantis has many genes involved in breaking down glycoproteins in mother's milk in order to release the oligosaccharides. Mother's milk coevolved over millions of years with mammals, and with their beneficial gut microbiota that it helped to thrive. "It is the only food that co-evolved with humans to make us healthy," said Mills.


News Article | September 9, 2016
Site: http://www.chromatographytechniques.com/rss-feeds/all/rss.xml/all

Turns out bacteria may transfer to candy that has fallen on the floor no matter how fast you pick it up. Rutgers researchers have disproven the widely accepted notion that it's OK to scoop up food and eat it within a "safe" five-second window. Donald Schaffner, professor and extension specialist in food science, found that moisture, type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second. Their findings appear online in the American Society for Microbiology's journal, Applied and Environmental Microbiology. "The popular notion of the 'five-second rule' is that food dropped on the floor, but picked up quickly, is safe to eat because bacteria need time to transfer," Schaffner said, adding that while the pop culture "rule" has been featured by at least two TV programs, research in peer-reviewed journals is limited. "We decided to look into this because the practice is so widespread. The topic might appear 'light' but we wanted our results backed by solid science," said Schaffner, who conducted research with Robyn Miranda, a graduate student in his laboratory at the School of Environmental and Biological Sciences, Rutgers University-New Brunswick. The researchers tested four surfaces - stainless steel, ceramic tile, wood and carpet - and four different foods (watermelon, bread, bread and butter, and gummy candy). They also looked at four different contact times - less than one second, five, 30 and 300 seconds. They used two media - tryptic soy broth or peptone buffer - to grow Enterobacter aerogenes, a nonpathogenic "cousin" of Salmonella naturally occurring in the human digestive system. Transfer scenarios were evaluated for each surface type, food type, contact time and bacterial prep; surfaces were inoculated with bacteria and allowed to completely dry before food samples were dropped and left to remain for specified periods. All totaled 128 scenarios were replicated 20 times each, yielding 2,560 measurements. Post-transfer surface and food samples were analyzed for contamination. Not surprisingly, watermelon had the most contamination, gummy candy the least. "Transfer of bacteria from surfaces to food appears to be affected most by moisture," Schaffner said. "Bacteria don't have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food." Perhaps unexpectedly, carpet has very low transfer rates compared with those of tile and stainless steel, whereas transfer from wood is more variable. "The topography of the surface and food seem to play an important role in bacterial transfer," Schaffner said. So while the researchers demonstrate that the five-second rule is "real" in the sense that longer contact time results in more bacterial transfer, it also shows other factors, including the nature of the food and the surface it falls on, are of equal or greater importance. "The five-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food," Schaffner said. "Bacteria can contaminate instantaneously."


News Article
Site: http://phys.org/biology-news/

Fish produce a lot of ammonia, which is a waste product from their protein metabolism. Ammonia also pollutes the water in which they live, and in excessive concentrations can even be deadly. "We humans excrete excess ammonia in our urine, through urea. Fish do so through their gills," explains microbiologist Huub Op den Camp. "In Nijmegen we specialise in identifying and propagating ammonia-eating bacteria such as anammox." The gills were therefore a logical first place to start looking for nitrogen cycle bacteria in fish. The research indeed showed that the gills of both zebrafish and carp are filled with micro-organisms. To identify these micro-organisms, microbiologists used a variety of microscopic techniques and isotope measurements, in addition to DNA finger printing. "Preparing gills for experiments was challenging, it was much different than what we are accustomed to," says Mike Jetten. "The cartilage in the branchial arch makes it extremely difficult to slice thin sections for microscopic study." But the microbiologists ultimately succeeded: Figure 1 shows electron microscope images of the bacteria in the gill tissue. Ultimately the biologists removed the gills from the fish for further study. Even then, they still produced nitrogen gas, which means that the bacteria remained active. The biologists also wanted to determine exactly how much ammonia the bacteria eat. To do this, they had to determine the nitrogen balance in aquariums. This was a difficult task due to the continuous water exchange and biofilters, which also remove some ammonia. In intermittently fed fish, it turned out that 31% of the feed ends up in the water as ammonia. In continuously fed fish this was only 18%; much of the ammonia had been converted to nitrogen gas, which escaped harmlessly from the water. The discovery of a new type of symbiosis does not happen very often. "At some point during evolution, fish accepted these bacteria, which turned out to be a successful strategy," says Op den Camp. "The question is now whether the bacteria are also present in species other than zebrafish and carp. We suspect that this symbiosis is common in freshwater fish, but that remains to be confirmed." This study also provides a lesson for aquaculture. "Feeding leads to a peak in the ammonia production. For the symbiosis between fish and bacteria, it is better if the ammonia production is more constant. It is therefore better to feed often with small amounts than with large amounts once or twice a day. The bacteria – and therefore the fish – benefit from this feeding tactic. Nearly all organisms benefit from constancy." Explore further: Unexpected interaction between ocean currents and bacteria More information: Maartje A.H.J. van Kessel et al. Branchial nitrogen cycle symbionts can remove ammonia in fish gills, Environmental Microbiology Reports (2016). DOI: 10.1111/1758-2229.12407


News Article
Site: http://www.rdmag.com/rss-feeds/all/rss.xml/all

​Biogas is an important energy source that plays a central role in the energy revolution. Unlike wind or solar energy, biogas can be produced around the clock. Could it soon perhaps even be produced to meet demand? A team of international scientists, including microbiologists from the Helmholtz Centre for Environmental Research (UFZ), scientists from Aarhus University and process engineers from the Deutsches Biomasseforschungszentrum (DBFZ), have been studying the feasibility of this kind of flexible biogas production. Among their findings, for example, is the discovery that biogas production can be controlled by altering the frequency at which the reactors are fed. If the intervals are longer, more biogas is produced, according to the researchers' paper in the Applied and Environmental Microbiology journal. Biogas production has long been a valuable technology, as the constant feed of organic raw materials such as energy crops, manure, sewage sludge, catch crops and plant residues helps produce energy around the clock. The ability to produce energy at a constant rate is a clear advantage over other renewable energy sources such as wind or solar energy, which depend on the wind or sun for production. As a result of this ability, Germany currently has around 8,000 biogas plants installed, with a total electricity output of approximately 4,500 megawatts. Around seven percent of the electricity generated in Germany now comes from biomass. It is hoped that even more electricity will be produced from this source in the future. Scientists from the UFZ, the University of Aarhus (Denmark) and the DBFZ succeeded in increasing the production of methane, the most valuable component of biogas, by up to 14 percent under laboratory conditions when the scientists added the substrate to the fermentation tank at intervals of between one and two days compared to the conventional interval of every two hours feeding. The results were astonishing: "Feeding the reactor less often results in greater energy yield", said Marcell Nikolausz, PhD, UFZ researcher at the Department of Environmental Microbiology and corresponding author of the study. The researchers fed two 15-litre reactors with distiller's dried grains with solubles (DDGS) under identical conditions for a total period of almost four months. DDGS is a by-product of bioethanol production using starchy grains. The researchers fed one reactor with DDGS every two hours. The other reactor was fed with the entire quantity once per day, in one experiment, and once every other day in a second experiment. The results were surprising. If the full quantity of biomass was fed into the fermentation tank just once a day, 14 percent more methane and 16 percent more total biogas is produced. If the tank was fed every two days, methane yield increased by 13 percent and biogas yield increased by 18 percent. One explanation for this could be that the greater variations in environmental conditions, particularly the fluctuating substrate concentration, increased the diversity of the microbial community, leading to more functional groups of bacteria. "This gives the micro-organisms more ways to degrade the substrate more efficiently", said microbiologist Nikolausz. He explained that this accelerates production and provides the micro-organisms with better conditions in which to process the biomass more efficiently, especially the components that are difficult to degrade. This flexible feeding management approach has no negative effect on the stability of the biogas production process. The researchers proved this by using T-RFLP profiles of the micro-organisms. This method can be used to verify the genetic fingerprint of the community of bacteria and methanogenic archaea that convert the organic material to biogas in the reactor. In case of the bacteria that convert the complex components of the biomass, such as cellulose, starch, lipids and proteins, into carbon dioxide, hydrogen and acetic acids, in several stages, the composition of these bacterial communities varies in the different feeding regimes. This is because the concentrations of ammonium nitrogen and hydrogen vary, as does the pH value. "The environment in the reactor is more dynamic when it is fed daily or every other day. This creates more functional niches, benefiting certain hydrolysing and acid-producing bacteria", said Nikolausz. In contrast, the community of methanogenic archaea, which in the final stage produce methane, water and carbon dioxide, remained stable. Regardless of how often the reactor was fed with biomass, the Methanosarcina genus, with a relative proportion of up to 83 percent of all methanogens, was consistently dominant followed by the genus Methanobacterium, which constituted up to 31 percent of all methanogens. "Both genera appear to adapt well to the changing conditions", Nikolausz explained. Research into flexible biogas production by employing feeding management is still in its infancy. The UFZ researchers plan to delve deeper into the results of the study. According to Nikolausz, the research results now need to be confirmed by trials in larger reactors. The use of other substrates is also an interesting subject. "We are keen to see whether we can also confirm that higher quantities of methane are produced when corn silage or sugar beets are used," said Nikolausz.


News Article | September 12, 2016
Site: http://www.cemag.us/rss-feeds/all/rss.xml/all

Turns out bacteria may transfer to candy that has fallen on the floor no matter how fast you pick it up. Rutgers University researchers have disproven the widely accepted notion that it’s okay to scoop up food and eat it within a “safe” five-second window. Donald Schaffner, professor and extension specialist in food science, found that moisture, type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second. Their findings appear online in the American Society for Microbiology’s journal, Applied and Environmental Microbiology. “The popular notion of the ‘five-second rule’ is that food dropped on the floor, but picked up quickly, is safe to eat because bacteria need time to transfer,” Schaffner says, adding that while the pop culture “rule” has been featured by at least two TV programs, research in peer-reviewed journals is limited. “We decided to look into this because the practice is so widespread. The topic might appear ‘light’ but we wanted our results backed by solid science,” says Schaffner, who conducted research with Robyn Miranda, a graduate student in his laboratory at the School of Environmental and Biological Sciences, Rutgers University-New Brunswick. The researchers tested four surfaces — stainless steel, ceramic tile, wood, and carpet — and four different foods (watermelon, bread, bread and butter, and gummy candy). They also looked at four different contact times — less than one second, five, 30, and 300 seconds. They used two media — tryptic soy broth or peptone buffer — to grow Enterobacter aerogenes, a nonpathogenic “cousin” of Salmonella naturally occurring in the human digestive system. Transfer scenarios were evaluated for each surface type, food type, contact time, and bacterial prep; surfaces were inoculated with bacteria and allowed to completely dry before food samples were dropped and left to remain for specified periods. All totaled 128 scenarios were replicated 20 times each, yielding 2,560 measurements. Post-transfer surface and food samples were analyzed for contamination. Not surprisingly, watermelon had the most contamination, gummy candy the least. “Transfer of bacteria from surfaces to food appears to be affected most by moisture,” Schaffner says. “Bacteria don’t have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food.” Perhaps unexpectedly, carpet has very low transfer rates compared with those of tile and stainless steel, whereas transfer from wood is more variable. “The topography of the surface and food seem to play an important role in bacterial transfer,” Schaffner says. So while the researchers demonstrate that the five-second rule is “real” in the sense that longer contact time results in more bacterial transfer, it also shows other factors, including the nature of the food and the surface it falls on, are of equal or greater importance. “The five-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food,” Schaffner says. “Bacteria can contaminate instantaneously.”

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