Internal Standard Addition System for Online Breath Analysis.

Breath analysis with secondary electrospray ionization (SESI) coupled to mass spectrometry (MS) is a sensitive method for breath metabolomics. To enable quantitative assessments using SESI-MS, a system was developed to introduce controlled amounts of gases into breath samples and carry out standard addition experiments. The system combines gas standard generation through controlled evaporation, humidification, breath dilution, and standard injection with the help of mass-flow controllers. The system can also dilute breath, which affects the signal of the detected components. This response can be used to filter out contaminating compounds in an untargeted metabolomics workflow. The system's quantitative capabilities have been shown through standard addition of pyridine and butyric acid into breath in real time. This system can improve the quality and robustness of breath data.

Association of the short-chain fatty acid levels and dietary quality with type 2 diabetes: a case-control study based on Henan Rural Cohort.

Evidence of the relationship between fecal short-chain fatty acids (SCFA) levels, dietary quality and type 2 diabetes mellitus (T2DM) in rural populations is limited. Here, we aimed to investigate the association between fecal SCFA levels and T2DM and the combined effects of dietar quality on T2DM in rural China. In total, 100 adults were included in the case-control study. Dietary quality was assessed by the Alternate Healthy Eating Index 2010 (AHEI-2010), and SCFA levels were analysed using the GC-MS system. Generalised linear regression was conducted to calculate the OR and 95 % CI to evaluate the effect of SCFA level and dietary quality on the risk of T2DM. Finally, an interaction was used to study the combined effect of SCFA levels and AHEI-2010 scores on T2DM. T2DM participants had lower levels of acetic and butyric acid. Generalised linear regression analysis revealed that the OR (95 % CI) of the highest acetic and butyric acid levels were 0·099 (0·022, 0·441) and 0·210 (0·057, 0·774), respectively, compared with the subjects with the lowest tertile of level. We also observed a significantly lower risk of T2DM with acetic acid levels > 1330·106 µg/g or butyric acid levels > 585·031 µg/g. Moreover, the risks of higher acetic and butyric acid levels of T2DM were 0·007 (95 % CI: 0·001, 0·148), 0·005 (95 % CI: 0·001, 0·120) compared with participants with lower AHEI-2010 scores (all P < 0·05). Acetate and butyrate levels may be important modifiable beneficial factors affecting T2DM in rural China. Improving dietary quality for body metabolism balance should be encouraged to promote good health.

[Relationship between short-chain fatty acids in the gingival crevicular fluid and periodontitis of stage â ¢ or â £].

OBJECTIVE: To analyze the concentration of formic acid, propionic acid and butyric acid in gingival crevicular fluid (GCF) of patients with stages Ⅲ and Ⅳ periodontitis, and their relationship with periodontitis. METHODS: The study enrolled 37 systemically healthy patients with periodontitis and 19 healthy controls who visited Department of Periodontology, Peking University School and Hospital of Stomatology from February 2008 to May 2011. Their GCFs were collected from the mesial-buccal site of one molar or incisor in each quadrant. Periodontal clinical parameters, including plaque index(PLI), probing depth(PD), bleeding index(BI), and attachment loss(AL). Concentrations of formic acid, propionic acid and butyric acid in the supernatant of the GCFs were analyzed by high-performance capillary electrophoresis (HPCE). The prediction ability of formic acid, propionic acid and butyric acid with the risk of periodontitis and the differences between grade B and grade C periodontitis were analyzed. RESULTS: In this study, 32 patients with stage Ⅲ and 5 patients with stage Ⅳ were enrolled, including 9 patients with grade B and 28 patients with grade C. Clinical periodontal variables in the patients with periodontitis were significantly higher than those in the control group (P<0.001). Formic acid was significantly lower in periodontitis than that in the control group [5.37 (3.39, 8.49) mmol/L vs. 12.29 (8.35, 16.57) mmol/L, P<0.001]. Propionic acid and butyric acid in periodontitis were significantly higher than those in the control group: Propionic acid, 10.23 (4.28, 14.90) mmol/L vs. 2.71 (0.00, 4.25) mmol/L, P < 0.001; butyric acid, 2.63 (0.47, 3.81) mmol/L vs. 0.00 (0.00, 0.24) mmol/L, P<0.001. There was no significant difference in formic acid, propionic acid and butyric acid concentrations between grade B and grade C periodontitis (P>0.05). Propionic acid and butyric acid in the deep pocket were significantly higher than in the shallow pocket, while the concentration of formic acid decreased with the increase of PD. Propionic acid (OR=1.51, 95%CI: 1.29-1.75) and butyric acid (OR=3.72, 95%CI: 1.93-7.17) were risk factors for periodontitis, while formic acid (OR=0.87, 95%CI: 0.81-0.93) might be a protective factor for periodontitis. Propionic acid (AUC=0.852, 95%CI: 0.805－0.900), butyric acid (AUC=0.889, 95%CI: 0.841－0.937), f (formic acid, AUC=0.844, 95%CI: 0.793－0.895) demonstrated a good predictive capacity for the risk of periodontitis. CONCLUSION: The concentration of formic acid decrease in the GCF of periodontitis patients, which is a protective factor for periodontitis, its reciprocal have good predictive capacity. However, propionic acid and butyric acid increase, which are risk factors for periodontitis and have good predictive capacity. The concentration of formic acid, propionic acid, and butyric acid vary with probing depth, but there is no significant difference between grade B and grade C periodontitis.

Variation of Aroma Components of Pasteurized Yogurt with Different Process Combination before and after Aging by DHS/GC-O-MS.

Pasteurized yogurt is a healthy yogurt that can be stored in ambient temperature conditions. Dynamic headspace sampling (DHS) combined with gas chromatography-olfactory mass spectrometry (GC-O-MS), sensory evaluation, electronic nose (E-nose), and partial least squares discriminant analysis (PLS-DA) were used to analyze the flavor changes of pasteurized yogurt with different process combinations before and after aging. The results of odor profiles showed that the sensory descriptors of fermented, sweet, and sour were greatly affected by different process combinations. The results of odor-active compounds and relative odor activity value (r-OAV) showed that the combination of the production process affected the overall odor profile of pasteurized yogurt, which was consistent with the sensory evaluation results. A total of 15 odor-active compounds of 38 volatile compounds were detected in pasteurized yogurt samples. r-OAV results revealed that hexanal, (E)-2-octenal, 2-heptanone, and butanoic acid may be important odor-active compounds responsible for off-odor in aged, pasteurized yogurt samples. PLS-DA and variable importance of projection (VIP) results showed that butanoic acid, hexanal, acetoin, decanoic acid, 1-pentanol, 1-nonanal, and hexanoic acid were differential compounds that distinguish pasteurized yogurt before and after aging.

[The study of the content of short-chain fatty acids in the intestine of people with lipid metabolism disorders].

Dyslipidemias are a risk factor for cardiovascular diseases, especially at a young age. It is known from modern sources that shortchain fatty acids (SCFA) synthesized in the intestine are actively involved in the genesis of dyslipidemia, the spectrum and ratio of which depends on the consumed food substrates. In particular, it has been found that food components such as dietary fiber can affect the lowering of blood lipids by affecting the intestinal microbiota. Therefore, dietary correction can be an important step in the prevention and treatment of dyslipidemia, and as a result, help reduce the risk of developing cardiovascular disease (CD). The aim of the research was to study the content of the main SCFAs (acetate, propionate, butyrate) in the feces of people with dyslipidemia, including taking into account the actual nutrition and consumption of the carbohydrate fraction of the diet (starch, mono- and disaccharides, dietary fiber) as precursors of SCFAs. Material and methods. 70 patients aged 18 to 45 years with dyslipidemia were selected as stool donors. All subjects were divided into 2 groups: the main group with the risk of CD (the risk was determined by the risk scale for CD) and the comparison group with established cardiovascular pathology (CVP). SCFAs in stool samples collected after natural defecation and subjected to immediate freezing at -70 °C were determined by gas chromatography. The diet was analyzed by the 24-hour food recall method. Results. The frequency of occurrence of the optimal ratio acetate - acetic acid : propionate - propionic acid : butyrate - butyric acid (60:20:20) in all groups was no more than 25%. At the same time, in persons at risk of CD, in the SCFA pool there was a pronounced decrease in the proportion of butyrate, which is characterized by cardioprotective properties, up to 15% (with an optimal proportion of 20%) compared with the levels for healthy people noted in the works of M.D. Ardatskaya et al. and A.A. Kurmangulov. And in persons with CVP, the levels of fecal acetate, which is a regulator of metabolic processes, namely lipogenesis, differed insignificantly compared with the values obtained in the studies of the above authors. In all examined individuals, the content of acetate in feces depended on the carbohydrate component of the diet, primarily on the total amount of carbohydrates consumed. And increasing the amount of dietary fiber intake contributed to the elevation of this SCFA. In individuals at risk of CD a significant correlation was found between the content of acetate and the atherogenic index (r=0,695). And in persons with CVP, there was a high negative correlation between the level of acetate in the feces and the amount of mono- and disaccharides in the diet (r=-0,934). Conclusion. In individuals with dyslipidemia and CVD risk factors, the results obtained in this study confirm the need for targeted correction of diets in order to increase the proportion of food substrates, which are potential precursors of butyrate.

High-altitude exposure decreases bone mineral density and its relationship with gut microbiota: Results from the China multi-ethnic cohort (CMEC) study.

BACKGROUND: Geographic altitude is a potent environmental factor for human microbiota and bone mineral density. However, little evidence exists in population-based studies with altitude diversity ranges across more than 3000 m. This study assessed the associations between a wide range of altitudes and bone mineral density, as well as the potential mediating role of microbiota in this relationship. METHODS: A total of 99,556 participants from the China Multi-Ethnic Cohort (CMEC) study were enrolled. The altitude of each participant was extracted from global Shuttle Radar Topography Mission (SRTM) 4 data. Bone mineral density was measured by calcaneus quantitative ultrasound index (QUI). Stool samples were collected for 16S rRNA gene sequencing (n = 1384). The metabolites of gut microbiota, seven kinds of short-chain fatty acids (SCFAs), were detected by gas chromatography-mass spectrometry (GC-MS, n = 128). After screening, 73,974 participants were selected for the "altitude-QUI" analysis and they were placed into the low-altitude (LA) and high-altitude (HA) groups. Additionally, a subgroup (n = 1384) was further selected for the "altitude-microbiota-QUI" analysis. Multivariate linear regression models and mediation analyses were conducted among participants. RESULTS: A significant negative association between high-altitude and QUI was obtained (mean difference = -0.373 standard deviation [SD], 95% confidence interval [CI]: -0.389, -0.358, n = 73,974). The same negative association was also observed in the population with microbiota data (mean difference = -0.185 SD, 95%CI: -0.360, -0.010, n = 1384), and a significant mediating effect of Catenibacteriumon on the association between altitude and QUI (proportion mediated = 25.2%, P = 0.038) was also noticed. Additionally, the acetic acid, butyric acid, and total amount of seven SCFAs of the low-altitude group were significantly higher than that of the high-altitude group (P < 0.05). CONCLUSION: High-altitude exposure may decrease bone mineral density in adults, thus increasing the risk of osteoporosis. The modulation of gut microbiota may be a potential strategy for alleviating the decrease of bone mineral density.

Microbial community structure, co-occurrence network and fermentation characteristics of woody plant silage.

BACKGROUND: Feed shortage is a factor restricting animal production in the tropics, therefore how to use natural woody plant resources as animal feed is an important strategy. RESULTS: Under the dual stress of an anaerobic and acidic environment, the microbial response during the fermentation of paper mulberry (PM) silage was found to be sensitive. The Gram-negative bacteria and mould died, and the dominant microbial community rapidly shifted to Gram-positive bacteria, resulting in a large reduction in microbial diversity and abundance. Exogenous bran additives interfered with the stress effects of the woody silage environment. Wheat bran (WB) accelerated the response of microorganisms to the anaerobic stress, and lactic acid bacteria became the dominant microbial community, thereby enhancing the lactic acid fermentation of silage, affecting the metabolic pathways of microorganisms, and improving the flavour and quality of the silage. Addition of rice bran made Enterobacter and Clostridium species quickly respond to the stress of the silage environment and become the predominant bacterial groups. In particular, anaerobic and spore-forming Clostridium species showed a strong tolerance to the silage environment, leading to butyric acid fermentation and protein degradation of the silage, and reducing its fermentation quality. CONCLUSION: The PacBio single-molecule real-time (SMRT) sequencing technology accurately revealed the microbial co-occurrence network and fermentation mechanism of silage. Our results indicate that PM can be used in combination with WB to prepare high-quality silage for animal production. © 2021 Society of Chemical Industry.

The propionic acid and butyric acid in serum but not in feces are increased in patients with diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Short-chain fatty acids (SCFAs) alteration have been reported in irritable bowel syndrome (IBS), but the results are conflicting. Our study aims to explore the alteration of SCFAs in patients with diarrhea-predominant IBS (IBS-D) and their potential role in the occurrence and development of IBS. METHODS: We recruited patients with IBS-D defined by Rome IV criteria and age-and-gender matched healthy controls (HCs). A headspace solid-phase microextraction gas chromatography-mass spectrometric (HS-SPME-GC-MS) method was developed for the analysis of acetic, propionic and butyric acid in feces and serum. RESULTS: Compared with HCs, the levels of the serum propionate (2.957 ± 0.157 vs 2.843 ± 0.098 mmol/L, P = 0.012) and butyrate (2.798 ± 0.126 vs 2.697 ± 0.077 mmol/L, P = 0.012) were significantly higher in IBS-D group. No significant differences were found among two groups with regard to the concentration of fecal acetate (4.953 ± 1.065 vs 4.774 ± 1.465 mg/g, P = 0.679), propionate (6.342 ± 1.005 vs 6.282 ± 1.077 mg/g, P = 0.868) and butyrate (2.984 ± 0.512 vs 3.071 ± 0.447 mg/g, P = 0.607). CONCLUSIONS: Metabolites of gut microbiota, the propionic and butyric acid, are increased in patients with IBS-D in serum but not in feces. It suggests that propionic and butyric acid might be associated with the occurrence and development of IBS.

Identification and Field Testing of Volatile Components in the Sex Attractant Pheromone Blend of Female House Mice.

Recently, it was reported (i) that the sex pheromone blend of male house mice, Mus musculus, comprises not only volatile components (3,4-dehydro-exo-brevicomin; 2-sec-butyl-4,5-dihydrothiazole) but also a component of low volatility (the sex steroid testosterone), and (ii) that the sex steroids progesterone and estradiol are sex pheromone components of female house mice. Here we tested the hypothesis that the sex attractant pheromone blend of female mice, analogous to that of male mice, also comprises volatile pheromone components. Analyzing by GC-MS the head space volatiles of bedding soiled with urine and feces of laboratory-kept females and males revealed three candidate pheromone components (CPCs) that were adult female-specific: butyric acid, 2-methyl butyric acid and 4-heptanone. In a two-choice laboratory experiment, adult males spent significantly more time in the treatment chamber baited with both the synthetic steroids (progesterone, estradiol) and the synthetic CPCs than in the paired control chamber baited only with the synthetic steroids. In field experiments, trap boxes baited with both the CPCs and the steroids captured 6.7-times more adult males and 4.7-times more juvenile males than trap boxes baited with the steroids alone. Conversely, trap boxes baited with both the CPCs and the steroids captured 4.3-times more adult males and 2.7-fold fewer adult females than trap boxes baited with the CPCs alone. In combination, these data support the conclusion that butyric acid, 2-methyl butyric acid and 4-heptanone are part of the sex attractant pheromone of female house mice. With progesterone and estradiol being pheromone components of both female brown rats, Rattus norvegicus, and female house mice, these three volatile components could impart specificity to the sexual communication system of house mice, brown rats and possibly other rodent species.

On the Effect of Aqueous Ammonia Soaking Pre-Treatment on Continuous Anaerobic Digestion of Digested Swine Manure Fibers.

(1) Background: The continuously increasing demand for renewable energy sources renders anaerobic digestion as one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most biogas plants. Their economical profitable operation, however, relies on increasing the methane yield from the solid fraction of manure, which is not so easily degradable. The solid fraction after anaerobic digestion, the so-called digested fibers, consists mainly of hardly biodegradable material and comes at a lower mass per unit volume of manure compared to the solid fraction before anaerobic digestion. Therefore, investigation on how to increase the biodegradability of digested fibers is very relevant. So far, Aqueous Ammonia Soaking (AAS), has been successfully applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester to enhance their methane productivity in batch experiments. (2) Methods: In the present study, continuous experiments at a mesophilic (38 °C) CSTR-type anaerobic digester fed with swine manure first and a mixture of manure with AAS-treated digested fibers in the sequel, were performed. Anaerobic Digestion Model 1 (ADM1) previously fitted on manure fed digester was used in order to assess the effect of the addition of AAS-pre-treated digested manure fibers on the kinetics of anaerobic digestion process. (3) Results and Conclusions: The methane yield of AAS-treated digested fibers under continuous operation was 49-68% higher than that calculated in batch experiments in the past. It was found that AAS treatment had a profound effect mainly on the disintegration/hydrolysis rate of particulate carbohydrates. Comparison of the data obtained in the present study with the data obtained with AAS-pre-treated raw manure fibers in the past revealed that hydrolysis kinetics after AAS pre-treatment were similar for both types of biomasses.

Gut Microbiota Dysbiosis in Children with Relapsing Idiopathic Nephrotic Syndrome.

BACKGROUND: While the etiology of idiopathic nephrotic syndrome (idiopathic nephrotic syndrome [INS]; characterized by repeated relapses and comorbid allergic conditions) remains unknown, recent evidence suggests that dysfunction in regulatory T cells (Tregs) plays an important role in the development of INS as well as allergic diseases. We hypothesized that dysbiosis involving decreased butyric acid-producing gut microbiota leads to defective induction and differentiation of peripherally induced Tregs, resulting in INS relapse. METHODS: Study subjects were 12 children with INS, 8 classified as relapsing (R group; median age: 3.0 years) and 4 as non-relapsing (NR group; median age: 4.3 years), and 11 healthy children (HC group; median age: 5.1 years) serving as normal controls. Measurement of microbiota was performed using 16S ribosomal RNA metagenomic analysis, and fecal butyric acid was measured using high performance liquid chromatography. Flow-cytometric analysis of Tregs and CD4-positive (CD4+) cells in peripheral blood was also performed. RESULTS: Metagenomic analysis of gut microbiota using feces showed that the proportion of butyric acid-producing bacteria was significantly lower in R (median 6.36%) than HC (median 18.84%; p = 0.0013), but no different between NR (median 16.71%) and HC (p = 0.29). Fecal organic acid analysis revealed significantly lower butyric acid quantities in R than HC (medians: 0.48 vs. 0.99 mg/g, p = 0.042). Circulating Tregs as a proportion of CD4+ cells were decreased in 75% of R and NR. CONCLUSION: Pediatric relapsing INS patients show gut microbiota dysbiosis, characterized by a decreased proportion of butyric acid-producing bacteria and lower fecal butyric acid quantities, concomitant with reduced circulatory Tregs.

Microbiological and chemical profiles of elephant grass inoculated with and without Lactobacillus plantarum and Pediococcus acidilactici.

The study was conducted to evaluate the microbiological and chemical profiles of elephant grass inoculated with and without different wild strains of lactic acid bacteria. Silage was prepared of four treatments and one control with three replicates as control (EKC, adding 2 ml/kg sterilizing water), Lactobacillus plantarum (USA commercial bacteria) (EKP), Lactobacillus plantarum (EKA), Pediococcus acidilactici (EKB), and Pediococcus acidilactici (SKD) isolated from King grass. Silage were prepared using polyethylene terephthalate bottles, and incubated at room temperature for different ensiling days. The pH and acetic acid (AA) were significantly (P < 0.05) reduced and lactic acid (LA), butyric acid (BA), and ethanol were significantly increased (P < 0.05) at 3, 5, 7, and 14 days in treatment groups as compared to control. Water-soluble carbohydrate (WSC) and NH3-N concentration was not affected at days 3, 5, and 7, but significantly (P < 0.05) reduced at 14 days in treatment groups as compared to control. The LA, BA, and ethanol were significantly (P < 0.05) increased and AA, WSC NH3-N, and yeast were significantly (P < 0.05) decreased at 30 days of ensiling in treatment groups as compared to control. It is recommended that the inoculation of LAB could improve the fermentation quality of elephant grass silage and further effort is needed to evaluate these effects on silage produced on farm scale and on animal production performance.

Supplementation with Lactobacillus paracasei or Pediococcus pentosaceus does not prevent diarrhoea in neonatal pigs infected with Escherichia coli F18.

Infectious diarrhoea is a worldwide problem in newborns. Optimal bacterial colonisation may enhance gut maturation and protect against pathogenic bacteria after birth. We hypothesised that lactic acid bacteria (LAB) administration prevents pathogen-induced diarrhoea in formula-fed newborns. Newborn caesarean-delivered, colostrum-deprived term piglets on parenteral nutrition for the first 15 h, were used as models for sensitive newborn infants. A commercially available probiotic strain, Lactobacillus paracasei F19 (LAP, 2·6×108 colony-forming units (CFU)/kg per d) and a novel LAB isolate, Pediococcus pentosaceus (PEP, 1·3×1010 CFU/kg per d), were administered for 5 d with or without inoculation of the porcine pathogen, Escherichia coli F18 (F18, 1010 CFU/d). This resulted in six treatment groups: Controls (n 9), LAP (n 10), PEP (n 10), F18 (n 10), F18-LAP (n 10) and F18-PEP (n 10). The pathogen challenge increased diarrhoea and density of F18 in the intestinal mucosa (P<0·05). LAB supplementation further increased the diarrhoea score, relative to F18 alone (P<0·01). Intestinal structure and permeability were similar among groups, whereas brush border enzymes were affected in variable intestinal regions with decreased activities in most cases after F18 and LAB inoculation. Bacterial density in colon mucosa increased after F18 inoculation (P<0·05) but was unaffected by LAB supplementation. In colon contents, acetic and butyric acids were increased by PEP (P<0·05). The LAB used in this study failed to reduce E. coli-induced diarrhoea in sensitive newborn pigs. In vulnerable newborns there may be a delicate balance among bacterial composition and load, diet and the host. Caution may be required when administering LAB to compromised newborns suffering from enteric infections.

Identification of bacteria using volatile organic compounds.

The rapid diagnosis of respiratory infections has always been an important goal for medical professionals, because rapid and accurate diagnosis leads to proper and timely treatment, and consequently, reduces the costs of incorrect and long-term treatments, and antibiotic resistance. The present study was conducted with the aim of detecting volatile organic compounds (VOCs) in three bacteria: Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae. Headspace of the studied bacteria, after separately culturing in two types of liquid medium in three different time-periods, was extracted by solid phase microextraction and analysed by gas chromatography mass spectrometry The analysis results of the VOCs produced by the studied bacteria indicate that some VOCs are common and some are unique in each bacterium. 1-penten-3-ol, levomenthol, and 2-octyl-1-ol for P. aeruginosa, cyclohexene, 4-ethenyl, and cis-Dihydro-α-terpinyl acetate for A. baumannii and 1,3-butadiene, butyraldehyde, longifolene, octyl acetate, tridecanol, dodecenal, (E)-2-hexyl ester, butanoic acid, and 5,5-dodecadinyl-1 12-diol for K. pneumoniae were identified as unique VOCs for each bacterium. Finally, it can be said that an accurate and rapid bacterial detection method can be achieved by using a tool that can detect bacterial VOCs. However, more studies are needed to design a tool for which all aspects have been assessed, so that it can give us a more complete pattern for the use of these compounds as biomarkers.

Probiotic supplementation effects on milk fatty acid profile in ewes.

We hypothesised that probiotic feeding would alter the fatty acid (FA) profile of sheep's milk. Sixteen lactating ewes, kept under the same feeding and management practices, were randomly allocated to receive either a control diet or the same diet supplemented with a commercial multi-strain bacterial probiotic. Milk fat FA contents were monitored fortnightly for eight consecutive weeks from 14 d after lambing. Probiotic supplementation increased the contents of butyric and caproic acids in milk fat and had no negative effects on other relevant FA from the human's health point of view (i.e., no differences in branched chain, vaccenic, rumenic and n-3 FA were observed). Under the conditions assayed in the present work, the contents of milk FA originated from rumen microbial metabolism were scantly altered, which suggests that the rumen conversion pathways of FA were not substantially modified by the probiotics.

Characteristics of lactic acid bacteria isolates and their effect on the fermentation quality of Napier grass silage at three high temperatures.

BACKGROUND: The poor fermentation quality of silage is an important issue for silage production during the high temperatures of summer. Pediococcus acidilactici GG13 (GG13) and Lactobacillus rhamnosus GG26 (GG26) isolated from Italian ryegrass (Lolium multiflorum Lam.) silage were characterised by morphological and physiological tests and 16S rRNA sequencing analysis, and their effects, along with those of a commercial lactic acid bacteria (LAB) inoculant (CB), on the fermentation quality of facultative halophyte Napier grass (Pennisetum purpureum Schumach) ensiled at 30 °C, 40 °C and 50 °C were studied, respectively. RESULT: The strains GG13 and GG26 grew well at 50 °C and pH 3.5, and were tolerant to 6.5% NaCl. After ensiling for 50 days, the strains GG13 and GG26 and the CB decreased (P < 0.001) the pH and acetic acid and ammonia-N contents and increased (P < 0.001) the lactic acid contents at 30 °C, and decreased (P < 0.001) the ammonia-N contents at 40 °C in Napier grass. CB did not affect the fermentation quality at 50 °C, whereas both isolated strains improved the fermentation quality of Napier grass silage as indicated by the lower (P < 0.001) pH, butyric acid and ammonia-N contents and higher (P < 0.001) lactic acid contents. The strain GG13 is better than GG26 with regard to improvement in fermentation quality of Napier grass silage. CONCLUSIONS: The results of this study suggested that strain GG13 is a good LAB inoculant for producing well-fermented silages during the high temperatures of summer times. © 2016 Society of Chemical Industry.

Variation in floral characters, particularly floral scent, in sapromyophilous Stemona species.

Flowers or inflorescences often deploy various signals, including visual, olfactory, and gustatory cues, that can be detected by their pollinators. In many plants, these cues and their functions are poorly understood. Deciphering the interactions between floral cues and pollinators is crucial for analyzing the reproductive success of flowering plants. In this study, we examined the composition of the fetid floral scents produced by several Stemona species, including nine S. tuberosa populations from across China, using dynamic headspace adsorption, gas chromatography, and mass spectrometry techniques. We compared variations in floral phenotype, including floral longevity, nectar rewards, pollinator behavior, and flower length and color among the Stemona species. Of the 54 scent compounds identified, the major compounds include fetid dimethyl disulfide, dimethyl trisulfide, 1-pyrroline, butyric acid, p-cresol, isoamyl alcohol, and indole. We detected striking differentiation in floral scent at both the species and population level, and even within a population of plants with different colored flowers. Floral characteristics related to sapromyophily and deceptive pollination, including flower color mimicking livor mortis and a lack of nectar, were found in five Stemona species, indicating that Stemona is a typical sapromyophilous taxon. Species of this monocot genus might employ evolutionary tactics to exploit saprophilous flies for pollination.

Isolation and molecular identification of lactic acid bacteria from King grass and their application to improve the fermentation quality of sweet Sorghum.

The aim of the present study was isolation and molecular identification of lactic acid bacteria from King grass and their application to improve the fermentation quality of sweet Sorghum. Seventy-six strains of LAB were isolated; five strains were selected for Physiological and morphological tests and 16S rRNA sequencing. All five strains grew at different pH 3.5-8.0, different temperature 35, 40, 45, 50 °C and different NaCl concentrations 3, 6.5, 9.5%. Strains HDASK were identified Lactobacillus plantarum and SK3907, SK2A32, SK3A42 and ASKDD Pediococcus acidilactici. Three isolated strains and one commercial strain were added to sweet sorghum. Silage was prepared of four treatments and one control with three replicates as control (SKC, adding 2 ml/kg sterilizing water), L. plantarum commercial bacteria (SKP), L. plantarum (HDASK) isolated from King grass (SKA), P. acidilactici (SK3907) isolated from King grass (SKB) and P. acidilactici (ASKDD) isolated from King grass (SKD). All silage were prepared using polyethylene terephthalate bottles, and incubated at room temperature for different ensiling days. The level of pH, acetic acid, NH3-N, water soluble carbohydrate and butyric acid was significantly (P < 0.05) decreased. Lactic acid, ethanol and propionic acid (PA) was significantly (P < 0.05) increased in treatments compared to control. The dry matter, propionic acid neutral detergent fiber, acid detergent fiber did not significantly (P < 0.05) differ among the treatments but the values were increased and decreased. The number of yeast, mold and LAB were significantly (P < 0.05). It is suggested that the supplementation of LAB could enhanced the fermentation quality of sweet Sorghum silage.

Effect of 2-hydroxy-4-methylthio-butanoic acid on ruminal fermentation, bacterial distribution, digestibility, and performance of lactating dairy cows.

The objective of this experiment was to test the effect of a Met analog, 2-hydroxy-4-methylthio-butanoic acid (HMTBa), on ruminal fermentation and microbial protein synthesis, nutrient digestibility, urinary N losses, and performance of dairy cows. Eight multiparous lactating Holstein dairy cows were assigned to 4 levels of HMTBa [0 (control), 0.05, 0.10, and 0.15% (dry matter basis)] in a replicated 4×4 Latin square trial. Experimental periods were 28 d, including 21 d for adaptation. Ruminal ammonia and microbial N were labeled through a 6-d intraruminal infusion of (15)NH4Cl, and microbial protein synthesis in the rumen was estimated using the reticular sampling technique. Treatment had no effect on dry matter intake (28.4 to 29.8kg/d), milk yield (44.1 to 45.3kg/d), feed efficiency, and milk composition. Total-tract apparent digestibility of nutrients was generally not affected by treatment, except digestibility of crude protein and starch decreased quadratically with HMTBa supplementation. Fecal, but not urinary, and total excreta N losses were increased quadratically by HMTBa. Ruminal pH, ammonia concentration, protozoal counts, and the major volatile fatty acids were not affected by treatment. Microbial N outflow from the rumen was linearly increased by HMTBa. 2-Hydroxy-4-methylthio-butanoic acid linearly increased the proportion of Fecalibacterium and quadratically decreased the proportion of Eubacterium in ruminal contents. Of the individual bacterial species, HMTBa increased or tended to increase Prevotella loescheii and Prevotella oralis. 2-Hydroxy-4-methylthio-butanoic acid linearly increased the concentration (and yield) of 15:0 in milk fat. In the conditions of this crossover experiment, HMTBa had no effect on feed intake and performance of dairy cows, decreased dietary crude protein digestibility, and increased microbial N outflow from the rumen.

Response of chronic gingivitis to hygiene therapy and experimental gingivitis. Clinical, microbiological and metabonomic changes.

PURPOSE: To compare the clinical, microbiological and metabonomic profiles of subjects with high and low levels of chronic gingival bleeding during a controlled oral hygiene regimen intervention including sequential phases of rigorous therapeutic oral hygiene followed by experimental gingivitis (EG). METHODS: Two cohorts of qualified study subjects with differences in gingival bleeding on probing levels at their baseline clinical examination were entered into the study. These two cohorts were followed through three separate study phases including a 1-week baseline phase, a 2-week phase of rigorous oral hygiene including dental prophylaxis, and a 3-week EG phase of no oral hygiene to encourage relapse of gingivitis. The 58 subjects were assessed during each phase of the study for clinical presentation of gingivitis and concurrently had plaque sampled for real-time polymerase chain reaction (RTPCR) microbiological characterization and salivary lavage samples for 'systems biology' metabonomics assessment by 1H-NMR. RESULTS: Subjects presenting with different levels of gingival bleeding on probing when they entered the study responded differently to rigorous oral hygiene and EG. Specifically, the high bleeding cohort responded sluggishly to rigorous oral hygiene and exhibited markedly greater relapse to gingivitis during EG. RTPCR analysis showed changes in bacterial populations that were associated with study phases, particularly the increases in putative periodontal pathogens during EG. However, the microbiological profiles of high- and low-susceptibility gingival bleeding patients were largely similar. Metabonomic analysis likewise revealed significant changes in metabolite composition during study phases associated with differences in plaque toxicity, especially the short chain carboxylic acids propionate and n-butyrate, which tracked clinical changes in gingivitis severity. Systems analysis of metabonomic changes suggested differences between cohorts, although analysis to date has not elucidated whether these differences are causative (population predictive) or simply diagnostic of clinical status within populations.