Total Bacterial Numbers Research Articles

Bacillus subtilis KCCM 11965P를 이용한 붉은팥 발효물의 항산화 활성 및 이화학성분 분석

Health of human intestine has deteriorated due to excessive stress and western diet. In this study, Vigna angularis was fermented by Bacillus subtilis KCCM11965P in order to develop prebiotic resource for improving bowel movement. The contents of ash and crude protein were 3.35±0.04% and 21.1±0.19% respectively. Vigna angularis extract (1, 3, 5%) were incubated with 3% (v/v) Bacillus subtilis KCCM 11965P for 0, 24, 48, and 72 h. Total bacterial numbers showed that the combination of 3% powdered seeds and 72 h incubation time was optimum condition for this experiment. Total polyphenol content increased from 0.18±0.010 mg/mL in pre-incubation to 0.23±0.007 mg/mL in post-incubation with the condition mentioned above. DPPH radical scavenging activity also increased from 36.1±6.0% to 63.6±5.2%. Analysis of protease activity showed 2.69±0.003 unit/mL in combination of 5% powdered seeds and 72 h incubation time. Amylase activity increased from 1.0±0.1 unit/mL in pre-incubation to 26.0±0.2 unit/mL in post-incubation. The analysis of free amino acids after incubation with Bacillus subtilis KCCM 11965P showed that leucine increased from 5.22 mg/L to 67.59 mg/L and tyrosine, one of non-essential amino acid also increased 10.08 mg/L to 259.35 mg/L by incubation with 5% powdered seeds. Most of organic acid were reduced by incubation for 72 h. These results suggest that Vigna angularis could be utilized most as a prebiotic resources.

Interactive effects of temperature, organic carbon, and pipe material on microbiota composition and Legionella pneumophila in hot water plumbing systems

BackgroundSeveral biotic and abiotic factors have been reported to influence the proliferation of microbes, including Legionella pneumophila, in hot water premise plumbing systems, but their combined effects have not been systematically evaluated. Here, we utilize simulated household water heaters to examine the effects of stepwise increases in temperature (32–53 °C), pipe material (copper vs. cross-linked polyethylene (PEX)), and influent assimilable organic carbon (0–700 μg/L) on opportunistic pathogen gene copy numbers and the microbiota composition, as determined by quantitative polymerase chain reaction and 16S rRNA gene amplicon sequencing.ResultsTemperature had an overarching influence on both the microbiota composition and L. pneumophila numbers. L. pneumophila peaked at 41 °C in the presence of PEX (1.58 × 105 gene copies/mL). At 53 °C, L. pneumophila was not detected. Several operational taxonomic units (OTUs) persisted across all conditions, accounting for 50% of the microbiota composition from 32 to 49 °C and 20% at 53 °C. Pipe material most strongly influenced microbiota composition at lower temperatures, driven by five to six OTUs enriched with each material. Copper pipes supported less L. pneumophila than PEX pipes (mean 2.5 log10 lower) at temperatures ≤ 41 °C, but showed no difference in total bacterial numbers. Differences between pipe materials diminished with elevated temperature, probably resulting from decreased release of copper ions. At temperatures ≤ 45 °C, influent assimilable organic carbon correlated well with total bacterial numbers, but not with L. pneumophila numbers. At 53 °C, PEX pipes leached organic carbon, reducing the importance of dosed organic carbon. L. pneumophila numbers correlated with a Legionella OTU and a Methylophilus OTU identified by amplicon sequencing.ConclusionsTemperature was the most effective factor for the control of L. pneumophila, while microbiota composition shifted with each stepwise temperature increase. While copper pipe may also help shape the microbiota composition and limit L. pneumophila proliferation, its benefits might be constrained at higher temperatures. Influent assimilable organic carbon affected total bacterial numbers, but had minimal influence on opportunistic pathogen gene numbers or microbiota composition. These findings provide guidance among multiple control measures for the growth of opportunistic pathogens in hot water plumbing and insight into the mediating role of microbial ecological factors.

Aspergillus oryzae와 단백질 분해효소 첨가에 따른 콩알메주 된장의 이화학적 특성 변화

The purpose of this study was to investigate the physiochemical properties of Doenjang was fermented by added with fungi and protease. The moisture content and pH of Doenjang added with protease (WP) were lower than those of control w/o protease while the contents of titratable acidity, reducing sugar, and amino-type nitrogen in WP were higher than control. The α-amylase activities of Doenjang added with single and mixed Protease B were the highest at 4 weeks of fermentation period and protease activity of WP was about 4 times higher than that of control. The 4-9 kinds of free amino acids (proline, isoleucine, leucine, and phenylalanine etc.) in WP was increased in comparison with control. The DPPH radical scavenging activity and total polyphenol content were higher in WP than control. Total aerobic bacterial and fungal numbers were decreased depending on fermentation time regardless of addition of protease. In conclusion, the protease can be used as additives improving the quality and taste of fermented Doenjang.

Bacterial communities in ancient permafrost profiles of Svalbard, Arctic.

Permafrost soils are unique habitats in polar environment and are of great ecological relevance. The present study focuses on the characterization of bacterial communities from permafrost profiles of Svalbard, Arctic. Counts of culturable bacteria range from 1.50 × 103 to 2.22 × 105 CFU g-1 , total bacterial numbers range from 1.14 × 105 to 5.52 × 105 cells g-1 soil. Bacterial isolates are identified through 16S rRNA gene sequencing. Arthrobacter and Pseudomonas are the most dominant genera, and A. sulfonivorans, A. bergeri, P. mandelii, and P. jessenii as the dominant species. Other species belong to genera Acinetobacter, Bacillus, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Rhodococcus, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus. To the best of our knowledge, genera Acinetobacter, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus are the first northernmost records from Arctic permafrost. The present study fills the knowledge gap of culturable bacterial communities and their chronological characterization from permafrost soils of Ny-Ålesund (79°N), Arctic.

Moringa oleifera leaf meal as an environmental friendly protein source for ruminants: Biomethane and carbon dioxide production, and fermentation characteristics

Ruminal fermentation produces methane (CH4) and carbon dioxide (CO2) which contribute to global warming. Therefore, several enteric CH4 and CO2 mitigation strategies have been explored recently. In this trial the effect of replacing soybean meal, as the sole protein source in a control total mixed ration (TMR) with Moringa oleifera leaf meal (MLM) at different levels, on ruminal fermentation characteristics were studied. M. oleifera leaf meal replaced (g/100 g DM): 0 (TMR0, control), 10 (TMR10), 20 (TMR20), 30 (TMR30), 40 (TMR40), 50 (TMR50), 60 (TMR60), 70 (TMR70), 80 (TMR80), 90 (TMR90), and 100 (TMR100) of soybean meal in the rations. Rations were incubated for 48 h using rumen inoculums from goats and steers. Some interactions between inoculum × TMR were observed (P < 0.05) for gas production (GP) parameters, CH4 production, and fermentation profile. Moreover, most parameters determined responded differently between animal species. Rations containing MLM decreased the asymptotic GP (P < 0.01), while they increased (P < 0.01) the rate of GP and lag of GP with both inoculums. Decreased (P < 0.05) CH4 production and increased CO2 production (P < 0.05) were observed when MLM replaced soybean meal. Diets containing MLM decreased (P < 0.05) ruminal ammonia-N and total protozoal number, while increasing (P < 0.05) total bacterial number with both goat and steer inoculums. Replacing soybean meal with MLM increased (P < 0.05) fermentation pH, but decreased (P < 0.05) organic matter degradability (OMD) with goat inoculum. Conversely, a declined (P < 0.05) in SCFA concentrations, and enhanced (P < 0.05) OMD and DM degradability compared with the control diet was observed with diets containing MLM. It is concluded that replacing soybean meal in goat and steer diets negatively affected the nutritive value of diets but decreased CH4 production. From an environmental standpoint, the replacement of soybean meal with MLM is a potential sustainable strategy to reduce CH4 production from goats and steers, and thus mitigate greenhouse gas emissions. Goat inoculum was more efficient in reducing CH4 production than that of steers.

Plant-fed versus chemicals-fed rhizobacteria of Lucerne: Plant-only teabags culture media not only increase culturability of rhizobacteria but also recover a previously uncultured Lysobacter sp., Novosphingobium sp. and Pedobacter sp.

In an effort to axenically culture the previously uncultivable populations of the rhizobacteria of Lucerne (Medicago sativa L.), we propose plant-only teabags culture media to mimic the nutritional matrix available in the rhizosphere. Here, we show that culture media prepared from Lucerne powder teabags substantially increased the cultivability of Lucerne rhizobacteria compared with a standard nutrient agar, where we found that the cultivable populations significantly increased by up to 60% of the total bacterial numbers as estimated by Quantitative Real-time Polymerase Chain Reaction (qRT-PCR). Cluster analysis of 16S rDNA Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) of cultivable Colony-Forming Units (CFUs) revealed a more distinct composition and separation of bacterial populations recovered on the plant-only teabags culture media than those developed on a standard nutrient agar. Further, the new plant medium gave preference to the micro-symbiont Sinorhizobium meliloti, and succeeded in isolating a number of not-yet-cultured bacteria, most closely matched to Novosphingobium sp., Lysobacter sp. and Pedobacter sp. The present study may encourage other researchers to consider moving from the well-established standard culture media to the challenging new plant-only culture media. Such a move may reveal previously hidden members of rhizobacteria, and help to further explore their potential environmental impacts.

A novel plant-based-sea water culture media for in vitro cultivation and in situ recovery of the halophyte microbiome

The plant-based-sea water culture medium is introduced to in vitro cultivation and in situ recovery of the microbiome of halophytes. The ice plant (Mesembryanthemum crystallinum) was used, in the form of juice and/or dehydrated plant powder packed in teabags, to supplement the natural sea water. The resulting culture medium enjoys the combinations of plant materials as rich source of nutrients and sea water exercising the required salt stress. As such without any supplements, the culture medium was sufficient and efficient to support very good in vitro growth of halotolerant bacteria. It was also capable to recover their in situ culturable populations in the phyllosphere, ecto-rhizosphere and endo-rhizosphere of halophytes prevailing in Lake Mariout, Egypt. When related to the total bacterial numbers measured for Suaeda pruinosa roots by quantitative-PCR, the proposed culture medium increased culturability (15.3–19.5%) compared to the conventional chemically-synthetic culture medium supplemented with (11.2%) or without (3.8%) NaCl. Based on 16S rRNA gene sequencing, representative isolates of halotolerant bacteria prevailed on such culture medium were closely related to Bacillus spp., Halomonas spp., and Kocuria spp. Seed germination tests on 25–50% sea water agar indicated positive interaction of such bacterial isolates with the germination and seedlings’ growth of barley seeds.

Bacteria primarily metabolize at the active layer/permafrost border in the peat core from a permafrost region in western Siberia

The microbial activity in the soils of the permafrost-affected zones is assumed to be one of the major factors that modify the organic carbon and nitrogen cycle under current climate change. In contrast to the extensive research centered on bacterial abundance, diversity, and metabolic activity in permanently and seasonally frozen mineral soils from high latitudes, frozen peat (organic) environments remain poorly characterized in terms of the physiological diversity and metabolic potential of bacteria. The evolution of soil heterotroph microbial number and metabolic activity across the “seasonally thawed (active)—permanently frozen layer” boundary was studied on 100-cm-thick cores from frozen peat mounds located in the discontinuous permafrost zone in western Siberia. There was a systematic decrease of metabolic activity in the upper 40 cm of the peat core from the surface layers of the mosses and lichens towards the beginning of the frozen horizon, followed by an abrupt increase in bacterial metabolism exactly at the border between the thawed layer and the permafrost table. The aerobic viable cell count and total bacterial number from the active layer were similar to those from the permafrost peat layer. The highest metabolic activity was observed at the beginning of the frozen peat layer and might correspond to the highest availability of amino substrates, which were depleted in the active layer but preserved in the deeper frozen horizons. The enhanced microbial activity at the frozen peat-active layer boundary in western Siberia may persist for another 50–100 years based on the current rate of increase in active layer thickness.

Actual aspects of quality raw materials in the production of beverage technology

The relevance of the topic lies in the task of providing the beverage industry with high quality feedstock. In the brewing industry there is the problem of water quality. To solve this problem is possible by implementation of modern achievements of science and technology ( ultrasonic water treatment in the stage production of malt in the process of soaking and germination of malting barley.In this regard, we have justified the use of targeted ultrasonic treatment of water at the stage of malt production in the process of soaking and germinating barley intended for obtaining a beverage such as beer. As a result of our studies, we have established a positive effect of ultrasound on water quality when certain conditions are created. Such conditions are the parameters of ultrasound exposure: power and processing exposure. We have revealed regularities associated with the mechanism of ultrasound action on water quality; The optimal valuesof the parameters of ultrasonic action are determined, which allow obtaining a given level of quality of water due to the achievement of certain values of such parameters as rigidity, pH and total microbial number. The positive influence of ultrasonic treatment on the quality and properties of water under certain conditions; the regularities and the effective parameters of this impact. We used ultrasonic device (UZTA O OM 4/22). Water treatment at a frequency of 22 kHz, a power of 180-240 W, 3-5 minutes exposure achieves positive effects on quality metrics such as: rigidity, which is reduced by 14-22% of the initial value; pH, which decreases to 0.28-0.35 units; total bacterial number, which is reduced by 6-7 times.

Detection of Microbial Substitution in the Oral Cavity of Patients Undergoing Hematopoietic Stem Cell Transplantation with Vitek MSTM, a MALDI-TOF Mass Spectrometry System

IntroductionApproximately 70%-90% patients receiving hematopoietic stem-cell transplantation (HSCT) have oral mucositis (OM). HSCT-induced OM is a major complication of preparative regimens. The oral cavity of healthy individuals harbor several bacterial species. For example, the cheek and tongue harbor a number of Streptococcus species, while the predominant genera in the saliva are Prevotella, Streptococcus, and Veillonella. The resident flora are considered to be deeply linked with OM because they prevent colonization by exogenous organisms having pathogenic potential for local and systemic infections. However, the precise bacterial substitution occurring in HSCT patients with OM remains unclear. Here, we prospectively examined oral bacterial flora changes using VITEK MSTM (SYSMEX bioMérieux Co., Ltd., Tokyo, Japan)-an automated mass spectrometry (MS) microbial-identification system using matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) technology. It can detect about 650 bacterial and 105 fungal species. We aimed to determine whether oral microbial in HSCT can be detected by VITEK MSTM.Patient and MethodsThis prospective study included 16 patients (10 males, 6 females; median age 52 years) who underwent HSCT for hematological malignancies (auto-PBSCT = 3 patients, allo-PBSCT = 3 patients, CBT = 10 patients; preparative regimen: MAC = 11 patients, RIC = 2 patients, auto = 3 patients) in our hospital between December 2015 and July 2016. All were treated in reverse isolation in a laminar airflow-equipped room and received drugs to prevent bacterial, fungal, and herpes virus infection. We used VITEK MS for analyzing oral bacterial flora. OM was diagnosed according to NCICTCAE v4.0 and WHO scale, and oral health was assessed using the Revised Oral Assessment Guide (ROAG). Microbial samples were obtained using swabs from bilateral buccal mucosa, palate, and tongue. Samples were then incubated at 37‹C for 72-96 hours both aerobically and anaerobically. Finally, VITEK MS was used to identify bacterial species in samples. We evaluated the patients before initiating preparative regimen (1st), day −1 before HSCT (2nd), 7 days after HSCT (3rd), 14 days after HSCT (4th), and 30 days after HSCT (5th).ResultsThe percentage of patients with high-grade OM (CTCAE Grade 2-5, and WHO Grade 1-4) increased in days 7-14 and decreased at day 30 (Table). Total bacterial species numbers gradually decreased from days -1 through to 30. Many Streptococcus sp could be detected at the 1st or 2nd time point, but these speciesgradually decreased and were replaced with coagulase-negative staphylococci (CNS; Staphylococcus epidermidis in 10 patients, S. haemolyticus in 5 patients, S. lentus in 3 patients, andS. warneri in 3 patients). Before HSCT, Prevotella sp and Veillonella sp in the oral flora were detected in 10 and 9 patients, respectively. However, by 14 days after HSCT, Prevotella sp and Veillonella sp were isolated less often than other points. Candida sp was detected only after the preparative regimen.Discussion and ConclusionThis is the first prospective study to demonstrate microbial substitution in oral bacterial spices in HSCT patients using VITEK MS. VITEK MS allowed for the reliable identification of clinically relevant bacteria. We found that the oral bacterial species changed from Streptococcus sp, Prevotella sp, or Veillonella sp to CNS or Candida sp after HSCT. Our results suggest that oral microbial substitution possibly underlies high-grade OM after HSCT. We also suspect that microbial substitution is partly modified by antibiotics, considering that all study patients were treated with antimicrobial agents (including beta-lactam antibiotics). Indeed, the presence of many beta-lactam sensitive Streptococcus sp decreased, whereas that of beta-lactam resistant strains (CNS and Candida sp)increased. Finally, this study involved a small and heterogeneous patient population with varying characteristics. Therefore, our results require confirmation in a larger number of patients over a longer period. [Display omitted] DisclosuresHironaka:MEXT Supported Program for the Strategic Research Foundation at Private Universities: Research Funding.

The effect of Lupinus albus seeds on digestibility, performance and gastrointestinal tract indices in pigs

The effect of soya bean meal (SBM) substitution in the diet with white lupine (WL) seeds on performances and some parameters of the digestive tract of pigs were studied. The digestibility experiment was performed on 30 pigs using difference method combined with marker method, where one group was offered basal diet and in diet of experimental groups 25% of the basal diet was substituted with SBM or WL meal. The growth experiment was conducted on 48 pigs of approximately 20kg body weight. The animals from the control group were fed with diet containing SBM, whereas in the experimental groups 50% or 100% of SBM was substituted with WL seeds. At the end of the experiment, eight pigs from each group were euthanized, and digesta and tissues were sampled. The apparent total tract digestibility of crude protein and dry matter was higher (p<0.05), but crude fibre and ether extract were lower (p<0.05) in the WL seeds than in SBM. Substituting 50% of SBM in the control diet with WL seeds did not affect significantly pig performance. Total substitution of SBM with WL seeds impacted negatively pigs growth and feed intake (p<0.05), but it did not affect the length of villi and crypt depth. It also significantly increased ileum digesta viscosity and ammonia concentration in the ileum and caecum digesta. In the ileal digesta of animals offered WL seeds, an increased (p<0.05) total bacterial and Enterobacteriaceae numbers were found, whereas reduced number of yeast and mould was found in the caecal digesta. The substitution of 50% SBM with WL seeds in the growing pig diet did not affect pigs' results, but the total substitution significantly decreased the performance of pigs and affected intestinal ecology.

Influence of raw milk quality on processed dairy products: How do raw milk quality test results relate to product quality and yield?

This article provides an overview of the influence of raw milk quality on the quality of processed dairy products and offers a perspective on the merits of investing in quality. Dairy farmers are frequently offered monetary premium incentives to provide high-quality milk to processors. These incentives are most often based on raw milk somatic cell and bacteria count levels well below the regulatory public health-based limits. Justification for these incentive payments can be based on improved processed product quality and manufacturing efficiencies that provide the processor with a return on their investment for high-quality raw milk. In some cases, this return on investment is difficult to measure. Raw milks with high levels of somatic cells and bacteria are associated with increased enzyme activity that can result in product defects. Use of raw milk with somatic cell counts >100,000cells/mL has been shown to reduce cheese yields, and higher levels, generally >400,000 cells/mL, have been associated with textural and flavor defects in cheese and other products. Although most research indicates that fairly high total bacteria counts (>1,000,000 cfu/mL) in raw milk are needed to cause defects in most processed dairy products, receiving high-quality milk from the farm allows some flexibility for handling raw milk, which can increase efficiencies and reduce the risk of raw milk reaching bacterial levels of concern. Monitoring total bacterial numbers in regard to raw milk quality is imperative, but determining levels of specific types of bacteria present has gained increasing importance. For example, spores of certain spore-forming bacteria present in raw milk at very low levels (e.g., <1/mL) can survive pasteurization and grow in milk and cheese products to levels that result in defects. With the exception of meeting product specifications often required for milk powders, testing for specific spore-forming groups is currently not used in quality incentive programs in the United States but is used in other countries (e.g., the Netherlands).

Detailed comparison of bacterial communities during seasonal sludge bulking in a municipal wastewater treatment plant

In this study, pyrosequencing combined with clone library analysis, qPCR, and fluorescent in situ hybridization (FISH) were performed to identify detailed changes of bacterial and filamentous bacterial communities in activated sludge (AS) in 3 types of typical AS samples: sludge bulking (B-AS), excessive bulking (EB-AS), and non-bulking (N-AS). Sludge bulking resulted in a decrease in total bacterial numbers from (6.4 ± 0.18) × 108 gene copies/mL in N-AS to (2.4 ± 0.22) × 108 in EB-AS and a decrease in bacterial diversity from 2757 OTUs in N-AS to 2217 OTUs in EB-AS. With the occurrence of sludge bulking, Actinobacteria and Firmicutes increased sharply, whereas Proteobacteria, which was the predominant phylum in N-AS, decreased markedly. In addition, Nitrospirae, a major lineage of the nitrite-oxidizing bacteria, had quite a low abundance in EB-AS (0.15%), while it was relatively high in N-AS (1.17%). On the other hand, filamentous bacteria accounted for 28.77% and 5.72% of total sequences in EB-AS and N-AS, respectively. More interestingly, 11 types of filamentous bacteria were always present in 3 types of typical AS samples from different stages of sludge bulking, and most of them enriched in EB-AS compared to N-AS. It is noteworthy that, in addition to the frequently reported filamentous bacteria such as Candidatus M. parvicella and Tetrasphaera, novel filamentous species of Trichococcus might exist in this bulking WWTP. Our results reveal that sludge bulking are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the bulking phenomenon in AS.

Increased Gut Redox and Depletion of Anaerobic and Methanogenic Prokaryotes in Severe Acute Malnutrition.

Severe acute malnutrition (SAM) is associated with inadequate diet, low levels of plasma antioxidants and gut microbiota alterations. The link between gut redox and microbial alterations, however, remains unexplored. By sequencing the gut microbiomes of 79 children of varying nutritional status from three centers in Senegal and Niger, we found a dramatic depletion of obligate anaerobes in malnutrition. This was confirmed in an individual patient data meta-analysis including 107 cases and 77 controls from 5 different African and Asian countries. Specifically, several species of the Bacteroidaceae, Eubacteriaceae, Lachnospiraceae and Ruminococceae families were consistently depleted while Enterococcus faecalis, Escherichia coli and Staphylococcus aureus were consistently enriched. Further analyses on our samples revealed increased fecal redox potential, decreased total bacterial number and dramatic Methanobrevibacter smithii depletion. Indeed, M. smithii was detected in more than half of the controls but in none of the cases. No causality was demonstrated but, based on our results, we propose a unifying theory linking microbiota specificity, lacking anaerobes and archaea, to low antioxidant nutrients, and lower food conversion.

Resistant starch (RS) fermentation is prevented by low potency antibiotics (AB) neomycin and ampicillin

In a previous study we reduced bacterial genera that ferment RS with AB treatment then stopped AB prior to feeding RS. Subsequent fermentation of RS was good even without a transplant of microbiota from other rats fed RS and prior reduced bacterial genera increased (EB14). We now report use of the same AB (neomycin 0.5 g/L and ampicillin 1g/L in drinking water) at the same time as feeding RS. Sprague Dawley rats were assigned into one of four groups and fed ad libitum for four weeks. The groups included: 1. positive control (high RS, low fat diet [LF], no AB), 2. negative control (no RS, LF, no AB); 3. LF, high RS, AB; and 4. high fat (HF), high RS, AB. We measured effects of fermentation: pH of cecal contents, empty cecum weight (ECW), short‐chain fatty acids (SCFA), glucagon‐like peptide 1 (GLP‐1), RS in cecal contents, four bacterial genera known to be involved in fermentation of RS and total bacterial numbers. HF group 4 was included to see if AB might improve fermentation of RS compared to no AB because Cani et al. (2008) had reported that AB reduced endotoxemia in diet‐induced obesity. AB reduced Lactobacillus spp. and Bifidobacterium spp., but not Bacteroides spp. or total bacteria. Empty cecum weights of groups given AB and positive control were greater than the negative control. RS increased acetate and butyrate as well as decreased pH of cecal contents and increased empty cecum weights; AB treatment in both LF and HF prevented these effects (p&lt;0.05). AB also had double the amount of GLP‐1 in serum and double the amount of RS in cecal contents compared to positive control, and negative control had minimal amounts of both GLP‐1 and RS. Thus, it appears that half of the RS was not fermented in the positive control and AB eliminated fermentation of RS when given at the same time as feeding of RS. However, increased ECW and GLP‐1 are a concern for future use of AB for reduction of fermentation of RS for mechanistic studies.Support or Funding InformationFunding: Ingredion Incorporated and LSU AgCenter.

Bacterial community structure and variation in a full-scale seawater desalination plant for drinking water production

Microbial processes inevitably play a role in membrane-based desalination plants, mainly recognized as membrane biofouling. We assessed the bacterial community structure and diversity during different treatment steps in a full-scale seawater desalination plant producing 40,000 m3/d of drinking water. Water samples were taken over the full treatment train consisting of chlorination, spruce media and cartridge filters, de-chlorination, first and second pass reverse osmosis (RO) membranes and final chlorine dosage for drinking water distribution. The water samples were analyzed for water quality parameters (total bacterial cell number, total organic carbon, conductivity, pH, etc.) and microbial community composition by 16S rRNA gene pyrosequencing. The planktonic microbial community was dominated by Proteobacteria (48.6%) followed by Bacteroidetes (15%), Firmicutes (9.3%) and Cyanobacteria (4.9%). During the pretreatment step, the spruce media filter did not impact the bacterial community composition dominated by Proteobacteria. In contrast, the RO and final chlorination treatment steps reduced the Proteobacterial relative abundance in the produced water where Firmicutes constituted the most dominant bacterial group. Shannon and Chao1 diversity indices showed that bacterial species richness and diversity decreased during the seawater desalination process. The two-stage RO filtration strongly reduced the water conductivity (>99%), TOC concentration (98.5%) and total bacterial cell number (>99%), albeit some bacterial DNA was found in the water after RO filtration. About 0.25% of the total bacterial operational taxonomic units (OTUs) were present in all stages of the desalination plant: the seawater, the RO permeates and the chlorinated drinking water, suggesting that these bacterial strains can survive in different environments such as high/low salt concentration and with/without residual disinfectant. These bacterial strains were not caused by contamination during water sample filtration or from DNA extraction protocols. Control measurements for sample contamination are important for clean water studies.

Impact of environmental factors on bacterial communities in floodplain lakes differed by hydrological connectivity

We analysed total bacterial number and mean volume of cells at three sites in each of ten floodplain lakes in the Middle Basin of the Biebrza River, North-Eastern Poland to test bacterioplankton communities change according to the distance to the river. The composition of the bacterial communities was determined by fluorescent in situ hybridization method. Total number of bacteria in the lakes ranged from 4.0 to 7.48 cells × 10 6 mL −1 with dominance by Actinobacteria, the contribution of which was positively correlated with water level. Old river channels (side-arms) featured Alpha- and Gammaproteobacteria. The community of Betaproteobacteria was limited by concentration of dissolved organic carbon. Archaea, in spite of a minor role (<3.65% of DAPI-4′,6-diamidino-2-phenylindole) in the communities, showed a positive relation to floodplain lake isolation. Multivariate analysis demonstrated that bacterioplankton in riverine lakes was similar to that in rivers, while lakes with limited water exchange showed a similarity to fertile lakes. Water level and nutrients were among the factors determining bacterial community structure.

Estimating Symbiont Abundances and Gill Surface Areas in Specimens of the Hydrothermal Vent Mussel Bathymodiolus puteoserpentis Maintained in Pressure Vessels

The hydrothermal vent mussel Bathymodiolus puteoserpentis hosts gill-associated sulfur- and methane-oxidizing bacteria which sustain host nutrition and allow it to reach high densities at various sites along the northern Mid-Atlantic Ridge. Previous studies have demonstrated that in similar dual symbioses, relative abundances of each bacterial type could change following variations in symbiont substrate availabilities. In this study, pressurized recovery and incubations in pressure vessels were used to test whether B. puteoserpentis symbionts displayed similar behavior in the presence of symbiont substrates. The relative abundances of both types of symbionts were analyzed using fluorescence in situ hybridization (FISH) and group-specific gene copy numbers were assessed using qPCR. Specimens sampled using isobaric and non-isobaric recovery contained similar relative proportions (in surface coverage) of sulfur- and methane-oxidizing bacteria indicating that recovery type did not have impact on measured relative areas. Similarly, pressurized incubations with different substrates did lead to significant differences in the relative surface coverage of the two types of bacteria, although slight variations were measured with qPCR, suggesting changes in relative abundances of gene copy numbers but not in relative areas covered. Total gill surface areas and total bacterial numbers in specimens were estimated for the first time. Symbiont bearing-mussels display exchange surfaces about 20-fold higher than those found in similar-sized coastal mussels, and mean bacterial numbers of 2.5*1012 per specimen were estimated. This emphasizes that symbiotic mussels are a major reservoir of bacteria in vent ecosystems.

전자선 처리에 따른 마른 김(Porphyra tenera)의 미생물 저감화 효과와 저항성 세균의 동정

This study investigated the effect of electron beam (EB) treatment on the microbial reduction of dried laver (Porphyra tenera) and identified EB-resistant bacteria from the treated dried laver. After EB treatments of 4 kGy and 7 kGy, the numbers of total bacteria and EB-resistant bacteria were measured using tryptic soy agar and mannitol salt agar, respectively. The morphological and biochemical characteristics of each isolated EB-resistant bacteria were investigated and these bacteria were identified. Compared to the control (1.5±0.2)×106 CFU/g, the total bacterial number was significantly decreased to (5.4±0.5)×104 CFU/g and (1.1±0.6)×104 CFU/g after EB treatments of 4 kGy and 7 kGy, respectively. With a higher EB dosage, the number of red colonies was almost same, whereas the number of yellow colonies was significantly decreased to (3.3±1.2)×103 CFU/g and 0 CFU/g for 4 kGy and 7 kGy, respectively. All red and yellow colonies were gram-positive cocci, catalase-positive, and resistant to 3% and 5% NaCl media. From the 16S rDNA sequence analysis, yellow and red colonies were identified as either Micrococcus flavus or M. luteus, with 99% similarity for the yellow colonies, and Deinococcus proteolyticus and D. piscis, with 99% and 97% similarity for the red colonies, respectively.

The Use of Germinants to Potentiate the Sensitivity of Bacillus anthracis Spores to Peracetic Acid.

Elimination of Bacillus anthracis spores from the environment is a difficult and costly process due in part to the toxicity of current sporicidal agents. For this reason we investigated the ability of the spore germinants L-alanine (100 mM) and inosine (5 mM) to reduce the concentration of peracetic acid (PAA) required to inactivate B. anthracis spores. While L-alanine significantly enhanced (p = 0.0085) the bactericidal activity of 500 ppm PAA the same was not true for inosine suggesting some form of negative interaction. In contrast the germinant combination proved most effective at 100 ppm PAA (p = 0.0009). To determine if we could achieve similar results in soil we treated soil collected from the burial site of an anthrax infected animal which had been supplemented with spores of the Sterne strain of B. anthracis to increase the level of contamination to 104 spores/g. Treatment with germinants followed 1 h later by 5000 ppm PAA eliminated all of the spores. In contrast direct treatment of the animal burial site using this approach delivered using a back pack sprayer had no detectable effect on the level of B. anthracis contamination or on total culturable bacterial numbers over the course of the experiment. It did trigger a significant, but temporary, reduction (p < 0.0001) in the total spore count suggesting that germination had been triggered under real world conditions. In conclusion, we have shown that the application of germinants increase the sensitivity of bacterial spores to PAA. While the results of the single field trial were inconclusive, the study highlighted the potential of this approach and the challenges faced when attempting to perform real world studies on B. anthracis spores contaminated sites.