scholarly journals Condensed Tannins Affect Bacterial and Fungal Microbiomes and Mycotoxin Production during Ensiling and upon Aerobic Exposure

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Kai Peng ◽  
Long Jin ◽  
Yan D. Niu ◽  
Qianqian Huang ◽  
Tim A. McAllister ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Microbial Communities ◽  
Bacterial Diversity ◽  
Fungal Diversity ◽  
Condensed Tannins ◽  
Total Volatile ◽  
Content Type ◽  
Mycotoxin Production ◽  
Aerobic Stability

ABSTRACTPurple prairie clover (PPC;Dalea purpureaVent.) containing 84.5 g/kg dry matter (DM) of condensed tannin (CT) was ensiled without (control) or with polyethylene glycol (PEG) for 76 days, followed by 14 days of aerobic exposure. Changes in fermentation characteristics were determined, and the composition of bacterial and fungal communities were assessed using metagenomic sequencing. The addition of polyethylene glycol (PEG) that deactivated CT at ensiling increased (P< 0.05 to ∼0.001) soluble N, nonprotein N, lactic acid, total volatile fatty acids, ammonia N, deoxynivalenol (DON), and ochratoxin A (OTA) but decreased (P< 0.001) pH and water-soluble carbohydrates. The concentrations of DON and OTA increased (P< 0.001) for both silages, with the extent of increase being greater for control than for PEG-treated silage during aerobic exposure. The PEG-treated silage exhibited higher (P< 0.01 to ∼0.001) copy numbers of total bacteria,Lactobacillus, yeasts, and fungi than the control. The addition of PEG decreased (P< 0.01) bacterial diversity during both ensiling and aerobic exposure, whereas it increased (P< 0.05) fungal diversity during aerobic exposure. The addition of PEG at ensiling increased (P< 0.05) the abundances ofLactobacillusandPediococcusspecies but decreased (P< 0.01) the abundances ofLactococcusandLeuconostocspecies. Filamentous fungi were found in the microbiome at ensiling and after aerobic exposure, whereasBacillusspp. were the dominate bacteria after aerobic exposure. In conclusion, CT decreased protein degradation and improved the aerobic stability of silage. These desirable outcomes likely reflect the ability of PPC CT to inhibit those microorganisms involved in lowering silage quality and in the production of mycotoxins.IMPORTANCEThe present study reports the effects of condensed tannins on the complex microbial communities involved in ensiling and aerobic exposure of purple prairie clover. This study documents the ability of condensed tannins to lower mycotoxin production and the associated microbiome. Taxonomic bacterial community profiles were dominated byLactobacillalesafter fermentation, with a notable increase inBacillusspp. as a result of aerobic exposure. It is interesting to observe that condensed tannins decreased bacterial diversity during both ensiling and aerobic exposure but increased fungal diversity during aerobic exposure only. The present study indicates that the effects of condensed tannins on microbial communities lead to reduced lactic acid and total volatile fatty acid production, proteolysis, and mycotoxin concentration in the terminal silage and improved aerobic stability. Condensed tannins could be used as an additive to control unfavorable microbial development and maybe enhanced feed safety.

scholarly journals Microbial Communities, Metabolites, Fermentation Quality and Aerobic Stability of Whole-Plant Corn Silage Collected from Family Farms in Desert Steppe of North China

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 784
Author(s):  
Chao Wang ◽  
Lin Sun ◽  
Haiwen Xu ◽  
Na Na ◽  
Guomei Yin ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Diversity ◽  
Fungal Diversity ◽  
North China ◽  
Bacterial Species ◽  
Fungal Species ◽  
Family Farms ◽  
Aerobic Stability ◽  
Whole Plant ◽  
Lactobacillus Kefiri

Whole-plant corn silages on family farms were sampled in Erdos (S1), Baotou (S2), Ulanqab (S3), and Hohhot (S4) in North China, after 300 d of ensiling. The microbial communities, metabolites, and aerobic stability were assessed. Lactobacillusbuchneri, Acinetobacter johnsonii, and unclassified Novosphingobium were present at greater abundances than others in S2 with greater bacterial diversity and metabolites. Lactobacillus buchneri, Lactobacillus parafarraginis, Lactobacillus kefiri, and unclassified Lactobacillus accounted for 84.5%, and 88.2%, and 98.3% of bacteria in S1, S3, and S4, respectively. The aerobic stability and fungal diversity were greater in S1 and S4 with greater abundances of unclassified Kazachstania, Kazachstania bulderi, Candida xylopsoci, unclassified Cladosporium, Rhizopus microspores, and Candida glabrata than other fungi. The abundances of unclassified Kazachstania in S2 and K. bulderi in S3 were 96.2% and 93.6%, respectively. The main bacterial species in S2 were L. buchneri, A. johnsonii, and unclassified Novosphingobium; Lactobacillus sp. dominated bacterial communities in S1, S3, and S4. The main fungal species in S1 and S4 were unclassified Kazachstania, K. bulderi, C. xylopsoci, unclassified Cladosporium, R. microspores, and C. glabrata; Kazachstania sp. dominated fungal communities in S2 and S3. The high bacterial diversity aided the accumulation of metabolites, and the broad fungal diversity improved the aerobic stability.

scholarly journals Metabolism of propane-1:2-diol infused into the rumen of sheep

1972 ◽  
Vol 27 (3) ◽  
pp. 553-560 ◽  
Author(s):  
J. L. Clapperton ◽  
J. W. Czerkawski
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Energy Metabolism ◽  
Heat Production ◽  
Volatile Fatty Acids ◽  
Carbon Dioxide Production ◽  
Total Volatile

1. Propane-1:2-diol (loog/d) was infused through a cannula into the rumen of sheep receiving a ration of hay and dried grass. The concentration of volatile fatty acids, propanediol, lactic acid and of added polyethylene glycol, and the pH of the rumen contents were measured. The energy metabolism of the sheep was also determined.2. Most of the propanediol disappeared from the rumen within 4 h of its infusion. The infusion of propanediol resulted in a 10% decrease in the concentration of total volatile acids; the concentration of acetic acid decreased by about 30%, that of propionic acid increased by up to 60% and there was no change in the concentration of butyric acid.3. The methane production of the sheep decreased by about 9% after the infusion of propanediol and there were increases in the oxgyen consumption, carbon dioxide production and heat production of the animals; each of these increases was equivalent to about 40% of the theoretical value for the complete metabolism of 100 g propanediol.4. It is concluded that, when propanediol is introduced into the rumen, a proportion is metabolized in the rumen and a large proportion is absorbed directly. Our thanks are due to Dr J. H. Moore for helpful discussions, to Mr D. R. Paterson, Mr J. R. McDill and Mr C. E. Park for looking after the animals and to Miss K. M. Graham, Miss A. T. McKay and Mrs C. E. Ramage for performing the analyses.

scholarly journals Oxygen-Inducible Conversion of Lactate to Acetate in Heterofermentative Lactobacillus brevis ATCC 367

2017 ◽  
Vol 83 (21) ◽  
Author(s):  
Tingting Guo ◽  
Li Zhang ◽  
Yongping Xin ◽  
ZhenShang Xu ◽  
Huiying He ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Brevis ◽  
Transcriptional Analysis ◽  
Wild Type ◽  
Content Type ◽  
Aerobic Stability ◽  
In The Wild ◽  
Acetate Accumulation ◽  
Yeasts And Molds ◽  
The Impact

ABSTRACT Lactobacillus brevis is an obligatory heterofermentative lactic acid bacterium that produces high levels of acetate, which improve the aerobic stability of silages against deterioration caused by yeasts and molds. However, the mechanism involved in acetate accumulation has yet to be elucidated. Here, experimental evidence indicated that aerobiosis resulted in the conversion of lactate to acetate after glucose exhaustion in L. brevis ATCC 367 (GenBank accession number NC_008497 ). To elucidate the conversion pathway, in silico analysis showed that lactate was first converted to pyruvate by the reverse catalytic reaction of lactate dehydrogenase (LDH); subsequently, pyruvate conversion to acetate might be mediated by pyruvate dehydrogenase (PDH) or pyruvate oxidase (POX). Transcriptional analysis indicated that the pdh and pox genes of L. brevis ATCC 367 were upregulated 37.92- and 18.32-fold, respectively, by oxygen and glucose exhaustion, corresponding to 5.32- and 2.35-fold increases in the respective enzyme activities. Compared with the wild-type strain, the transcription and enzymatic activity of PDH remained stable in the Δpox mutant, while those of POX increased significantly in the Δpdh mutant. More lactate but less acetate was produced in the Δpdh mutant than in the wild-type and Δpox mutant strains, and more H2O2 (a product of the POX pathway) was produced in the Δpdh mutant. We speculated that the high levels of aerobic acetate accumulation in L. brevis ATCC 367 originated mainly from the reuse of lactate to produce pyruvate, which was further converted to acetate by the predominant and secondary functions of PDH and POX, respectively. IMPORTANCE PDH and POX are two possible key enzymes involved in aerobic acetate accumulation in lactic acid bacteria (LAB). It is currently thought that POX plays the major role in aerobic growth in homofermentative LAB and some heterofermentative LAB, while the impact of PDH remains unclear. In this study, we reported that both PDH and POX worked in the aerobic conversion of lactate to acetate in L. brevis ATCC 367, in dominant and secondary roles, respectively. Our findings will further develop the theory of aerobic metabolism by LAB.

scholarly journals Succession of Microbial Communities of Corn Silage Inoculated with Heterofermentative Lactic Acid Bacteria from Ensiling to Aerobic Exposure

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 258
Author(s):  
Hao Guan ◽  
Qifan Ran ◽  
Haiping Li ◽  
Xinquan Zhang
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbial Communities ◽  
Single Molecule ◽  
Corn Silage ◽  
Water Control ◽  
Silage Fermentation ◽  
Aerobic Stability ◽  
Whole Plant

To further explore the effects of heterofermentative lactic acid bacteria (LAB) on silage fermentation and aerobic stability, whole-plant corn at around the 1/2 milk-line stage was freshly chopped and ensiled in laboratory silos with deionized water (control), Lactobacillus buchneri (LB), or L. rhamnosus (LR). Each treatment was prepared in triplicate for 3, 14, and 60 d of fermentation, followed by 3 and 7 days of aerobic exposure. The dynamic changes in microbial community were studied by single molecule real-time (SMRT) sequencing. The results showed that the two LAB inoculants altered the microbial communities in different ways. Succession from L. plantarum to L. buchneri and L. rhamnosus was observed in LB- and LR-treated silage, respectively. Both silages improved aerobic stability (82 and 78 h vs. 44 h) by occupying the microbial niche to produce higher levels of acetic acid at terminal fermentation. Because Acetobacter fabarum dominated in the silages after aerobic exposure, beta diversity dramatically decreased. In this study, a. fabarum was reported for the first time in silage and was related to aerobic spoilage. The two heterofermentative LAB produced acetic acid and improved the aerobic stability of the corn silage by occupying the microbial niche at terminal fermentation. Inoculated L. rhamnosus had a greater pH for a longer period of time after opening and less DM loss at day 7.

Effect of Polyethylene Glycol in Nanocellulose/PLA Composites

2019 ◽  
Vol 821 ◽  
pp. 89-95
Author(s):  
Wanasorn Somphol ◽  
Thipjak Na Lampang ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Modulus ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Mediated Oxidation

Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.

scholarly journals Dual sensor measurement shows that temperature outperforms pH as an early sign of aerobic deterioration in maize silage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guilin Shan ◽  
Wolfgang Buescher ◽  
Christian Maack ◽  
André Lipski ◽  
Ismail-Hakki Acir ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Aerobic Metabolism ◽  
Maize Silage ◽  
Aerobic Stability ◽  
Dual Sensor ◽  
Ruminant Diets ◽  
Incubation Temperatures ◽  
Biological Additive ◽  
Real Time Information ◽  
First Time

AbstractHigh quality silage containing abundant lactic acid is a critical component of ruminant diets in many parts of the world. Silage deterioration, a result of aerobic metabolism (including utilization of lactic acid) during storage and feed-out, reduces the nutritional quality of the silage, and its acceptance by animals. In this study, we introduce a novel non-disruptive dual-sensor method that provides near real-time information on silage aerobic stability, and demonstrates for the first time that in situ silage temperature (Tsi) and pH are both associated with preservation of lactic acid. Aerobic deterioration was evaluated using two sources of maize silage, one treated with a biological additive, at incubation temperatures of 23 and 33 °C. Results showed a time delay between the rise of Tsi and that of pH following aerobic exposure at both incubation temperatures. A 11 to 25% loss of lactic acid occurred when Tsi reached 2 °C above ambient. In contrast, by the time the silage pH had exceeded its initial value by 0.5 units, over 60% of the lactic acid had been metabolized. Although pH is often used as a primary indicator of aerobic deterioration of maize silage, it is clear that Tsi was a more sensitive early indicator. However, the extent of the pH increase was an effective indicator of advanced spoilage and loss of lactic acid due to aerobic metabolism for maize silage.

Lubricant compatibility of FKM seals in synthetic oils

2019 ◽  
Vol 72 (5) ◽  
pp. 557-565
Author(s):  
Dilek Bulut ◽  
Tatjana Krups ◽  
Gerhard Poll ◽  
Ulrich Giese
Keyword(s):  
Polyethylene Glycol ◽  
Design Methodology ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Standard Test ◽  
New Method ◽  
Static Tests ◽  
Content Type ◽  
Lip Seals ◽  
First Results

Purpose Elastomer seals are used in many applications. They are exposed to lubricants and additives at elevated temperatures, as well as mechanical stresses. They can only provide good sealing function when they have resistance to those factors. There are many elastomer-lubricant compatibility tests based on DIN ISO 1817 in industry. However, they are insufficient and costly. Correlations between the tests and the applications are inadequate. The purpose of this study is investigating lubricant compatibility of fluoroelastomers (FKM) seals in polyethylene-glycol (PG)- and polyalphaolefin (PAO)- based synthetic oils and developing a methodology to predict seal service life. Design/methodology/approach A new compatibility test which is more sufficient in terms of time and cost was developed and compared with a standard test, currently used in industry. Compatibility of FKM radial lip seals with PG- and PAO-based synthetic oils with different additives was investigated chemically and dynamically. Failure mechanisms were examined. Findings The new method and the Freudenberg Flender Test FB 73 11 008 showed similar results concerning damages and similar tendencies regarding wear. The additive imidazole derivative was the most critical. Static tests give indications of possible chemically active additives, but alone they are insufficient to simulate the dynamic applications. Originality/value The paper describes a new method to investigate elastomer-lubricant compatibility and gives first results with a variety of lubricants.

scholarly journals Cervicovaginal Microbiome Composition Is Associated with Metabolic Profiles in Healthy Pregnancy

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Andrew Oliver ◽  
Brandon LaMere ◽  
Claudia Weihe ◽  
Stephen Wandro ◽  
Karen L. Lindsay ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reproductive Health ◽  
Microbial Communities ◽  
Carbon Sources ◽  
Amplicon Sequencing ◽  
Vaginal Microbiome ◽  
Content Type ◽  
Healthy Women ◽  
Healthy Pregnancy ◽  
Tof Ms

ABSTRACT Microbes and their metabolic products influence early-life immune and microbiome development, yet remain understudied during pregnancy. Vaginal microbial communities are typically dominated by one or a few well-adapted microbes which are able to survive in a narrow pH range and are adapted to live on host-derived carbon sources, likely sourced from glycogen and mucin present in the vaginal environment. We characterized the cervicovaginal microbiomes of 16 healthy women throughout the three trimesters of pregnancy. Additionally, we analyzed saliva and urine metabolomes using gas chromatography-time of flight mass spectrometry (GC-TOF MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) lipidomics approaches for samples from mothers and their infants through the first year of life. Amplicon sequencing revealed most women had either a simple community with one highly abundant species of Lactobacillus or a more diverse community characterized by a high abundance of Gardnerella, as has also been previously described in several independent cohorts. Integrating GC-TOF MS and lipidomics data with amplicon sequencing, we found metabolites that distinctly associate with particular communities. For example, cervicovaginal microbial communities dominated by Lactobacillus crispatus have high mannitol levels, which is unexpected given the characterization of L. crispatus as a homofermentative Lactobacillus species. It may be that fluctuations in which Lactobacillus dominate a particular vaginal microbiome are dictated by the availability of host sugars, such as fructose, which is the most likely substrate being converted to mannitol. Overall, using a multi-“omic” approach, we begin to address the genetic and molecular means by which a particular vaginal microbiome becomes vulnerable to large changes in composition. IMPORTANCE Humans have a unique vaginal microbiome compared to other mammals, characterized by low diversity and often dominated by Lactobacillus spp. Dramatic shifts in vaginal microbial communities sometimes contribute to the presence of a polymicrobial overgrowth condition called bacterial vaginosis (BV). However, many healthy women lacking BV symptoms have vaginal microbiomes dominated by microbes associated with BV, resulting in debate about the definition of a healthy vaginal microbiome. Despite substantial evidence that the reproductive health of a woman depends on the vaginal microbiota, future therapies that may improve reproductive health outcomes are stalled due to limited understanding surrounding the ecology of the vaginal microbiome. Here, we use sequencing and metabolomic techniques to show novel associations between vaginal microbes and metabolites during healthy pregnancy. We speculate these associations underlie microbiome dynamics and may contribute to a better understanding of transitions between alternative vaginal microbiome compositions.

scholarly journals An Evolutionary Link between Natural Transformation and CRISPR Adaptive Immunity

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Peter Jorth ◽  
Marvin Whiteley
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Bacterial Diversity ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Comparative Genomic ◽  
Content Type ◽  
Immune Systems ◽  
Adaptive Immune ◽  
Adaptive Immune Systems

ABSTRACTNatural transformation by competent bacteria is a primary means of horizontal gene transfer; however, evidence that competence drives bacterial diversity and evolution has remained elusive. To test this theory, we used a retrospective comparative genomic approach to analyze the evolutionary history ofAggregatibacter actinomycetemcomitans, a bacterial species with both competent and noncompetent sister strains. Through comparative genomic analyses, we reveal that competence is evolutionarily linked to genomic diversity and speciation. Competence loss occurs frequently during evolution and is followed by the loss of clustered regularly interspaced short palindromic repeats (CRISPRs), bacterial adaptive immune systems that protect against parasitic DNA. Relative to noncompetent strains, competent bacteria have larger genomes containing multiple rearrangements. In contrast, noncompetent bacterial genomes are extremely stable but paradoxically susceptible to infective DNA elements, which contribute to noncompetent strain genetic diversity. Moreover, incomplete noncompetent strain CRISPR immune systems are enriched for self-targeting elements, which suggests that the CRISPRs have been co-opted for bacterial gene regulation, similar to eukaryotic microRNAs derived from the antiviral RNA interference pathway.IMPORTANCEThe human microbiome is rich with thousands of diverse bacterial species. One mechanism driving this diversity is horizontal gene transfer by natural transformation, whereby naturally competent bacteria take up environmental DNA and incorporate new genes into their genomes. Competence is theorized to accelerate evolution; however, attempts to test this theory have proved difficult. Through genetic analyses of the human periodontal pathogenAggregatibacter actinomycetemcomitans, we have discovered an evolutionary connection between competence systems promoting gene acquisition and CRISPRs (clustered regularly interspaced short palindromic repeats), adaptive immune systems that protect bacteria against genetic parasites. We show that competentA. actinomycetemcomitansstrains have numerous redundant CRISPR immune systems, while noncompetent bacteria have lost their CRISPR immune systems because of inactivating mutations. Together, the evolutionary data linking the evolution of competence and CRISPRs reveals unique mechanisms promoting genetic heterogeneity and the rise of new bacterial species, providing insight into complex mechanisms underlying bacterial diversity in the human body.

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