Increase In Bacterial Population Research Articles

Impact of compost and biochar from agricultural waste on reducing cadmium concentration and mancozeb residue in soil

The negative impact of excessive exposure to agrochemicals in shallot cultivation causes environmental pollution and human health. Biochar has the potential to absorb agrochemical contamination. This research aimed to investigate the effect of providing compost and biochar from agricultural waste on land quality, reducing the concentration of heavy metal cadmium (Cd) and mancozeb pesticide residues in soil and products in shallot. The experiment was carried out in shallot fields in Ngurensiti Village, Pati Regency, Central Java Province. Four different treatments, including combinations of biochar and compost, were applied, along with conventional controls. Data were analyzed using the F test (ANOVA) and Tukey's test using the Minitab statistical program version 16.0. The research showed that using biochar made from sugarcane bagasse, rice husk, corncob, and compost helped more soil bacteria grow and lowered Cd and mancozeb concentrations. In addition, treatment with biochar from sugarcane bagasse waste showed a decrease in Cd and mancozeb concentrations and a more significant increase in bacterial populations compared to other treatments (rice husk biochar and corncob biochar). Although there was a slight increase in Cd concentration in shallot leaves post-treatment, Cd levels in shallot bulbs remained within safe limits. This study shows that using biochar and compost from agricultural waste effectively improves soil quality, reduces heavy metal pollution, and lowers pesticide levels to support sustainable agriculture and protect people's health.

Effects of prolonged application of peracetic acid-based disinfectant on recirculating aquaculture systems stocked with Atlantic salmon parr

The use of recirculating aquaculture systems (RAS) for Atlantic salmon (Salmo salar) production has become increasingly common. RAS water disinfection plays a crucial role on its biosecurity. Peracetic acid (PAA) is a promising disinfectant due to its powerful oxidative properties, broad antimicrobial spectrum, and rapid degradation into no harmful compounds. This study focused on assessing the consequences of prolonged application of a PAA-based disinfectant in a RAS stocked with salmon parr. The experiment included three treatment groups in triplicate: 0 mg/L PAA (control), 0.1 mg/L PAA, and 1 mg/L PAA, using nine-replicated RAS with a total of 360 fish (14.8 ± 2.3 g; N = 40/RAS). The study spanned 28 days, with samples collected on days 0, 14, and 28. The analyzed parameters were water quality, and fish parameters, including external welfare indicators, gill histology, total antioxidant capacity (TAC), reactive oxygen species/reactive nitrogen species (ROC/RNC), oxidative stress biomarkers related to DNA and protein, cellular DNA damage, and global gene expression. While water quality remained relatively stable, there was an increase in bacterial populations in the groups exposed to PAA, particularly 1 mg/L PAA. Fish weight did not differ between the control and PAA-exposed groups. TAC, ROC/RNC, and oxidative stress biomarkers exhibited similar trends. The study identified >400 differentially expressed genes (DEGs) in the skin, gill, and olfactory organ, with many of these DEGs associated with immune responses. Comparing the transcriptomic profiles of the three tissue organs revealed that the olfactory organ was the most reactive to PAA treatment. This study shows that calculated PAA concentrations of 0.1 mg/L and 1 mg/L in the pump-sump, contributed to an increase of bacteria whereas no detectable differences in health and welfare of salmon parr were found. These findings are promising for the implementation of PAA-based disinfectants in RAS stoked with Atlantic salmon parr.

Exploring the possible relationship between skin microbiome and brain cognitive functions: a pilot EEG study

Human microbiota mainly resides on the skin and in the gut. Human gut microbiota can produce a variety of short chain fatty acids (SCFAs) that affect many physiological functions and most importantly modulate brain functions through the bidirectional gut-brain axis. Similarly, skin microorganisms also have identical metabolites of SCFAs reported to be involved in maintaining skin homeostasis. However, it remains unclear whether these SCFAs produced by skin bacteria can affect brain cognitive functions. In this study, we hypothesize that the brain’s functional activities are associated with the skin bacterial population and examine the influence of local skin-bacterial growth on event-related potentials (ERPs) during an oddball task using EEG. Additionally, five machine learning (ML) methods were employed to discern the relationship between skin microbiota and cognitive functions. Twenty healthy subjects underwent three rounds of tests under different conditions—alcohol, glycerol, and water. Statistical tests confirmed a significant increase in bacterial population under water and glycerol conditions when compared to the alcohol condition. The metabolites of bacteria can turn phenol red from red–orange to yellow, confirming an increase in acidity. P3 amplitudes were significantly enhanced in response to only oddball stimulus at four channels (Fz, FCz, and Cz) and were observed after the removal of bacteria when compared with that under the water and glycerol manipulations. By using machine learning methods, we demonstrated that EEG features could be separated with a good accuracy (> 88%) after experimental manipulations. Our results suggest a relationship between skin microbiota and brain functions. We hope our findings motivate further study into the underlying mechanism. Ultimately, an understanding of the relationship between skin microbiota and brain functions can contribute to the treatment and intervention of diseases that link with this pathway.

Impact assessment of thiamethoxam on microbial and enzymatic activity in mango rhizosphere

Thiamethoxam is a globally used neonicotinoid insecticide in mango ecosystem which can cause hazardous impact on soil environment. The current study was carried out to assess the impact of 0.2 (T1/treament) and 2.0 g kg−1 (T2) concentrations of thiamethoxam on mango rhizospheric microbial community, enzyme activity along with its degradation. Indigenous microflora degraded thiamethoxam from 5.62 to 41.17 mg kg−1 at 0 day to 0.60 and 2.10 mg kg−1 in soil after 60 days of application of 0.2 and 2.0 g kg−1 doses, respectively. Thiamethoxam dissipated via pseudo first-order kinetics with t1/2 (half-life) values (23.00 and 14.00) days and K values (1.99–17.14) and (21.42–183.6) at T1 and T2, respectively. At bacterial count of 5.5 × 107 in soil, fluorescein diacetate (FDA) and dehydrogenase (DHA) showed that there was no change occurred in control soil after 60 days, while in thiamethoxam treated soil DHA was marginally increased from 0.164 to 0.168 µg g−1 and from 0.155 to 0.157 µg g−1 at lower and higher doses, respectively. While, FDA values were slightly decreased from 0.761 to 0.717 µg g−1 at T1 but no significant change was observed in T2. However, changes in fungal population were not significant but increase in bacterial population with the degradation of thiamethoxam was observed, which indicated the presence of thiamethoxam degrading beneficial bacteria in mango rhizosphere soil.

Organic and natural farming improve microbial diversity and dehydrogenase activity in clusterbean-tomato cropping sequence

ABSTRACT Organic (OF) and natural farming (NF) may help to overcome drawbacks of chemical farming. A field experiment was conducted to investigate the microbial diversity and dehydrogenase activity in clusterbean-tomato cropping sequence with different farming systems over 3 years. An increase in bacterial population in OF (73.6%) and NF (55.4%) over conventional farming practice (PoP) and 90.8% (OF) and 62.1% (NF) over farmers’ practice (FP) was recorded. Fungal population in OF and NF increased by 32.8% and 12%, respectively over PoP and 76.8% (OF) and 47% (NF) over FP. Increase in actinomycetes population of 34% (OF) and 18.1% (NF) over PoP and 60.9% (OF) and 41.8% (NF) over FP was observed. Phosphate solubilizing microorganisms (PSM) population increased to 62.8% (OF) and 33.4% (NF) over PoP and 103.1% (OF) and 66.4% (NF) over FP. Population of N-Fixers also found enhanced in OF (31.4%) and NF (9.7%) compared to PoP and FP (OF: 97.4% and NF: 58%). The higher dehydrogenase activity of 41.4% (OF) and 25.5% (NF) was recorded over PoP and OF (62%) and NF (43.8%) over FP. It can be concluded that OF and NF enhanced microbial diversities and dehydrogenase activity.

Trade-off between microbial ecophysiological features regulated by soil fertility governs plant residue decomposition

Soil fertility influences microbial-driven plant residue decomposition, thus further affecting soil organic carbon (C) formation. Both ecological and physiological features of microbial communities change with soil fertilities, however, the mechanism of how soil fertility influences microbial ecophysiological features (both the taxonomic and functional profiles) driving plant residue decomposition is unclear. Here, four series of microcosms were set up, inoculated with two distinct soils, each with low and high fertility levels as a result of contrasting long-term fertilization regimes, and incubated with 13C-labeled rice straw amendments. DNA stable-isotope probing (DNA-SIP) based amplicon sequencing and shotgun metagenomic sequencing were conducted. We found that both bacterial community composition (including the relative abundance, α- and β-diversities, and taxonomic composition) and carbohydrate metabolic efficiency were significantly changed under different soil fertilities. High fertile soils gave rise to greater increases in bacterial populations and straw decomposition than low fertile soils, yet DNA-SIP-based shotgun metagenomic sequencing showed that the bacterial average carbohydrate metabolic efficiency, characterized by the average carbohydrate-active enzyme (CAZyme) abundance within each bacterial phylum was significantly lower. Linear regressions between bacterial ribosomal RNA operon (rrn) copy number and bacterial carbohydrate metabolic efficiency under contrasting soil fertilities suggested that high fertile soils select for fast-but-inefficient bacteria to degrade rice straw while low fertile soils select for slow-but-efficient ones. Collectively, the data demonstrate a fundamental trade-off between the ecological and physiological attributes of straw-degrading microbial communities. The trade-off is regulated by soil fertility and in turn governs plant residue decomposition. This work provides novel insights for better understanding the ecological and physiological roles of microbes in organic matter decomposition and global terrestrial C cycling, especially in the context of crop straw degradation under contrasting soil fertilities.

Growth productivity as a determinant of the inoculum effect for bactericidal antibiotics.

Understanding the mechanisms by which populations of bacteria resist antibiotics has implications in evolution, microbial ecology, and public health. The inoculum effect (IE), where antibiotic efficacy declines as the density of a bacterial population increases, has been observed for multiple bacterial species and antibiotics. Several mechanisms to account for IE have been proposed, but most lack experimental evidence or cannot explain IE for multiple antibiotics. We show that growth productivity, the combined effect of growth and metabolism, can account for IE for multiple bactericidal antibiotics and bacterial species. Guided by flux balance analysis and whole-genome modeling, we show that the carbon source supplied in the growth medium determines growth productivity. If growth productivity is sufficiently high, IE is eliminated. Our results may lead to approaches to reduce IE in the clinic, help standardize the analysis of antibiotics, and further our understanding of how bacteria evolve resistance.

PD53-06 CHANGES IN MOUSE STOOL MICROBIOME WITH EXPOSURE TO BLADDER CARCINOGEN N-BUTYL-N-(4-HYDROXYBUYTL) NITROSAMINE (BBN): LONGITUDINAL ANALYSIS

You have accessJournal of UrologyCME1 May 2022PD53-06 CHANGES IN MOUSE STOOL MICROBIOME WITH EXPOSURE TO BLADDER CARCINOGEN N-BUTYL-N-(4-HYDROXYBUYTL) NITROSAMINE (BBN): LONGITUDINAL ANALYSIS Rashida Ginwala, Laura Bukavina, Alexander Kutikov, Ilaha Isali, Mohit Sindhani, Megan Prunty, and Philip Abbosh Rashida GinwalaRashida Ginwala More articles by this author , Laura BukavinaLaura Bukavina More articles by this author , Alexander KutikovAlexander Kutikov More articles by this author , Ilaha IsaliIlaha Isali More articles by this author , Mohit SindhaniMohit Sindhani More articles by this author , Megan PruntyMegan Prunty More articles by this author , and Philip AbboshPhilip Abbosh More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002630.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The tobacco BBN is a commonly used carcinogen to model bladder cancer in rodents. The effect of tobacco on the gut microbiome is not well characterized. We used the BBN model to measure its effects on the gut microbiome given the emerging impact on carcinogenesis and therapeutic response in many types of tumors. METHODS: Starting at 8-12 weeks of age, male (N=33) and female (N=22) C57BL/6 mice were administered 0.05% BBN in drinking water for 12 weeks then switched to regular water. Controls limited to water. Stool was collected pre-exposure, after 6 and 12 weeks of exposure, and at the time of tumor identification. DNA extracted from stool was subjected to 16S PCR amplification of the bacterial 16S rRNA. Hierarchical clustering (PCoA), Shannon diversity index was used to quantify and compare microbial diversity across samples and time. In addition bacterial log abundance was calculated. RESULTS: Distinct clustering difference were present as determined by principal coordinate analysis (PCoA) across sex(p=0.024), but not BBN (p=0.86). Across all the BBN samples, estimation of abundance revealed an relative increase in bacterial populations of Bacteroidales (53%), Lactobacillales (17.5%), Coriobacteriales (19.87%) in females, while male mice exhibited an increase in Erysipelotrichales (14.76%). Bacterial order log abundance demonstrated Clostridiales (log change -7.79, padj <0.004), Veeruccomicrobiales (log change -2.21, padj <0.005), Bacillales (log -17.60, padj=0.005) were detected at a lower prevalence in BBN stool samples as compared to controls in females only, while male mice exhibited no significant differences. CONCLUSIONS: Pronounced microbial changes occur within stool induced by BBN in the murine model, with microbiome of the female mice exhibiting more significant flunctuations, suggesting a difference in BBN effect and metabolism across sex. Source of Funding: n/a © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e911 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Rashida Ginwala More articles by this author Laura Bukavina More articles by this author Alexander Kutikov More articles by this author Ilaha Isali More articles by this author Mohit Sindhani More articles by this author Megan Prunty More articles by this author Philip Abbosh More articles by this author Expand All Advertisement PDF DownloadLoading ...

Comparative Analysis of Microbial Consortiums and Nanoparticles for Rehabilitating Petroleum Waste Contaminated Soils.

Nano-bioremediation application is an ecologically and environmentally friendly technique to overcome the catastrophic situation in soil because of petroleum waste contamination. We evaluated the efficiency of oil-degrading bacterial consortium and silver nanoparticles (AgNPs) with or without fertilizer to remediate soils collected from petroleum waste contaminated oil fields. Physicochemical characteristics of control soil and petroleum contaminated soils were assessed. Four oil-degrading strains, namely Bacillus pumilus (KY010576), Exiguobacteriaum aurantiacum (KY010578), Lysinibacillus fusiformis (KY010586), and Pseudomonas putida (KX580766), were selected based on their in vitrohydrocarbon-degrading efficiency. In a lab experiment, contaminated soils were treated alone and with combined amendments of the bacterial consortium, AgNPs, and fertilizers (ammonium nitrate and diammonium phosphate). We detected the degradation rate of total petroleum hydrocarbons (TPHs) of the soil samples with GC-FID at different intervals of the incubation period (0, 5, 20, 60, 240 days). The bacterial population (CFU/g) was also monitored during the entire period of incubation. The results showed that 70% more TPH was degraded with a consortium with their sole application in 20 days of incubation. There was a positive correlation between TPH degradation and the 100-fold increase in bacterial population in contaminated soils. This study revealed that bacterial consortiums alone showed the maximum increase in the degradation of TPHs at 20 days. The application of nanoparticles and fertilizer has non-significant effects on the consortium degradation potential. Moreover, fertilizer alone or in combination with AgNPs and consortium slows the rate of degradation of TPHs over a short period. Still, it subsequently accelerates the rate of degradation of TPHs, and a negligible amount remains at the end of the incubation period.

The Intertrophic Relationship between Algae and Bacteria from the Activated Microalgae Granules

Activated microalgae granules, as a technology at its initial steps, require sustained efforts for a better understanding of the intertrophic relationship between algae and bacteria. The activated algae granules samples from extensive lab-scale sequencing batch reactor experiments were selected for a total DNA extraction and analysis. A relative quantitative analysis of bacterial genes involved in nitrification, denitrification, phosphorus accumulation as well as genes belonging to microalgae was performed by real-time PCR / qPCR. Microscopic investigations of activated microalgae granule showed a gradual decrease of microalgae concentration, together with an increase in bacterial populations inside the granule.

Seed-born Burkholderia glumae Infects Rice Seedling and Maintains Bacterial Population during Vegetative and Reproductive Growth Stage.

Rice world production is affected due to the growing impact of diseases such as bacterial panicle blight, produced by Burkholderia glumae. The pathogen-induced symptoms include seedling rot, grain rot and leaf-sheath browning in rice plants. It is currently recognized the entrance of this pathogen to the plant, from infected seeds and from environmental sources of the microorganism. However, it is still not fully elucidated the dynamics and permanence of the pathogen in the plant, from its entry until the development of disease symptoms in seedlings or panicles. In this work it was evaluated the infection of B. glumae rice plants, starting from inoculated seeds and substrates, and its subsequent monitoring after infection. Various organs of the plant during the vegetative stage and until the beginning of the reproductive stage, were evaluated. In both inoculation models, the bacteria was maintained in the plant as an endophyte between 1 × 101 and 1 × 105 cfu of B. glumae.g−1 of plant throughout the vegetative stage. An increase of bacterial population towards initiation of the panicle was observed, and in the maturity of the grain, an endophyte population was identified in the flag leaf at 1 × 106 cfu of B. glumae.g−1 fresh weight of rice plant, conducting towards the symptoms of bacterial panicle blight. The results found, suggest that B. glumae in rice plants developed from infected seeds or from the substrate, can colonize seedlings, establishing and maintaining a bacterial population over time, using rice plants as habitat to survive endophyticly until formation of bacterial panicle blight symptoms.

Size and stability of suspended aggregates in municipal effluents containing montmorillonite, bacteria and fulvic acid

Utilizing treated wastewater (TWW) for irrigation results in biological and chemical deposits. TWW components such as bacteria and suspend minerals interact under different environmental conditions, forming aggregates varying in size and stability that may adversely affect water flow in drippers. Our aim in this study was to characterize aggregates’ size and stability in suspensions of bacteria and clay particles, under different conditions prevailing in TWW. Flocculation value tests, thermal analysis, microscopy and particle size distribution were used to measure bacterial–clays interaction in suspension. Our results showed suspension stability increase with an increase in bacterial population. Dissolved organic carbon (DOC) produced by bacteria or added as fulvic acid was found to be the most important parameter involved in determining aggregate size and stability under similar environmental condition. The presence of these components most commonly resulted in higher stability of the suspension, mainly smaller particles in suspension. A novel measurement aimed to determine size and stability parameters for suspended particles has been established and was found to be useful in predicting suspended compound interactions.

16S rRNA Next Generation Sequencing Analysis Shows Bacteria in Alzheimer's Post-Mortem Brain.

The neurological deterioration associated with Alzheimer’s disease (AD), involving accumulation of amyloid-beta peptides and neurofibrillary tangles, is associated with evident neuroinflammation. This is now seen to be a significant contributor to pathology. Recently the tenet of the privileged status of the brain, regarding microbial compromise, has been questioned, particularly in terms of neurodegenerative diseases. It is now being considered that microbiological incursion into the central nervous system could be either an initiator or significant contributor to these. This is a novel study using 16S ribosomal gene-specific Next generation sequencing (NGS) of extracted brain tissue. A comparison was made of the bacterial species content of both frozen and formaldehyde fixed sections of a small cohort of Alzheimer-affected cases with those of cognitively unimpaired (normal). Our findings suggest an increase in bacterial populations in Alzheimer brain tissue compared with normal.

Glyphosate, 1,1’- dimethyl-4,4’-bipyridinium dichloride and Atrazine induces changes in Soil organic carbon, bacterial and fungal communities in a tropical alfisol

The increasing use of agrochemicals for weed control has raised concerns about their ecotoxicological effects on soil micro-biota communities and soil functions which serve as indicators of soil quality. Thus, this study was conducted to evaluate the effects of continuous field applied herbicides glyphosate, paraquat, atrazine and their combined forms over a period of five years on soil organic carbon, bacterial and fungal population in Akure, Ondo State Nigeria. Soil samples from farmer’s field which have been exposed to continuous herbicide application were collected and analysed for physio-chemical properties, organic carbon, total bacterial and fungal population. Simultaneously, soil samples designated as control were collected from adjacent fields with no history of herbicide application and analysed. Results showed a significant (P=0.05) 86% and 128% increase in bacterial population from glyphosate and atrazine treated fields respectively and 42% decrease in paraquat and Glyphosate + paraquat fields when compared with the untreated field. A significant 35% decrease in fungal population was observed in fields applied with atrazine and a further 10% decrease in fungal populations in all herbicide treated fields irrespective of herbicide type and combinations when compared with the untreated field. These changes also correlates with the abundance of beneficial microbes such as Pseudomonas aeruginosa, Pseudomonas fluorescens, Proteus mirabilis, Aspergillus flavius with a probable influence on plant growth promotion and potentials for biodegradation of persistent herbicides. SOC, SOM and pH was significantly (P=0.05) increased in atrazine and atrazine + paraquat treated fields when compared with the untreated fields and other herbicide treatments.

Antibacterial activity of four root canal sealers against Enterococcus Faecalis at 1st, 3rd, 5th, and 7th day duration: A In vitro study

Background: Root filling plays an important role in control of reinfection by entombing the residual organisms through antimicrobial activity of endodontic sealers. Several endodontic sealers have also been found to have antibacterial properties, depending on their chemical contents. Aim: Aim of the present study was to assess the antibacterial activity of 4 endodontic sealers i.e AH Plus (Group 1), Sealapex (Group 2), Roekoseal (Group 3) and ZOE (Group 4) against E. faecalis at 1hr, 1st, 3rd, 5th and 7th day duration. Materials and Methods: Antimicrobial activities of four root canal sealers were evaluated against E. faecalis at various time intervals by direct contact test. Freshly mixed sealers were placed in 96-well microtitre plates. Plates were placed for incubation at 37°C and thereafter placed in microplate reader wherein optical density in each well was measured at 630 nm. Readings were taken at regular intervals. i.e after 1 hr (fresh specimen), then on 1st, 3rd, 5th and 7th day. Statistical Analysis: Data was collected by recording optical density, considering the fact that as, bacterial population increases, absorbance reading, i.e. Optical Density (O.D.) given by spectrophotometer increases. Data were recorded, then plotted and statistically analyzed using 2 way -ANOVA (Analysis of Variance) and Newman-Keuls Post hoc procedure. Result: Intragroup comparison in various groups showed greatest antibacterial effect at 1 hr, followed by a decrease in the effectiveness at 1st day, 3rd day, 5thday, 7th day. In intergroup comparison, GROUP 2 (Sealapex) showed least inhibition of bacterial growth at 1 hr interval followed by further decrease at different studied intervals. Conclusion: It was concluded that Antibacterial activity of tested endodontic sealers on E. faecalis in an ascending order was as follows: Sealapex, Roekoseal, AH Plus and Zinc Oxide Eugenol sealer.

Structure–prebiotic properties relationship for α-D-glucan from Leuconostoc citreum SK24.002

Effects of non-chemical modification on structure and fermentability of α-D-glucan from Leuconostoc citreum SK24.002 were investigated. It was found that the apparent viscosity, molecular weight and percentage of α-1,6 linkage of α-D-glucan decreased after endodextranase or ultrasonic treatment. During in vitro fermentation, a strong increase in bacterial population was observed and the largest changes took place during the first 12 h of incubation. A decreased pH was also observed and gas production after 48 h fermentation increased at the following sequence: enzymatic treated α-D-glucan < ultrasonic treated α-D-glucan < α-D-glucan. The fermentation of modified sample resulted in a consistent generation of SCFA, particularly in the 12–48 h part of incubation. The concentrations of propionic acid and butyric acid at 48 h of fermentation were 60.4 and 19.1 mM for enzymatic treated α-D-glucan, respectively, higher than ultrasonic treated α-D-glucan or α-D-glucan. This showed that enzymatic hydrolysis could be a promising degradation method for the production of potential prebiotics.

Elucidating molecular structure and prebiotics properties of bioengineered α-D-glucan from Leuconostoc citreum SK24.002

The objective of this work was to produce the bioengineered α-D-glucan from Leuconostoc citreum SK24.002 and study its molecular structure and prebiotics properties. The connectivities and substitutions of α-D-glucan were measured using 2D NMR and the chain structure of the repeating unit was deduced. During in vitro fecal fermentation, a strong increase in bacterial population was observed and the largest changes took place during the first 24 h of incubation. A decrease pH (approximately 2.0) was also observed for the fermentation from 0 h to 48 h compared to the blank (pH 6.8–6.6). Total short-chain fatty acid (SCFA) increased during batch fecal fermentation in the presence of α-D-glucan and it reached the maximum level of 30.01 mM after 48 h of fermentation. The lowest gas production and highest butyric acid production at 48 h of incubation was recorded with α-D-glucan as compared with dextran or pullulan. Moreover, human fecal microbiota on α-D-glucan produced more butyric acid between 24 and 48 h than other test carbohydrates. These results suggest that α-D-glucan would be a good candidate slowly fermentable fiber and may have a positive effect for the gut microbiota homeostasis.

Defence-related enzymatic response in cabbage to Xanthomonas campestris pv. campestris

Black rot of cabbage caused by Xanthomonas campestris pv. campestris is one of the most important diseases of crucifers worldwide. Expression of defence-related enzymes in cabbage in response to X. campestris pv. campestris was investigated in the current experiment. Among the defence-related enzymes (phynylalanine ammonia lyase, peroxidase, polyphenol oxidase, superoxide dismutase [SOD] and chitinase) and quantity of phenolic compounds studied in the present investigation, phenylalanine ammonia lyase (PAL), the key enzyme in the phenylpropanoid pathway was the first enzyme suppressed at three days after inoculation in X. campestris pv. campestris-cabbage system. Correlation analysis indicated that PAL and phenolic compounds are the two most important compounds determining the susceptibility of cabbage to X. campestris pv. campestris. Induction of peroxidase isoform-1 (Rf value: 0.059) and SOD isoform-1 (Rf value: 0.179) three days after pathogen inoculation implicated the role of these isozymes in susceptible cabbage – X. campestris pv. campestris interaction. This study demonstrates the susceptibility of cabbage to X. campestris pv. campestris is a result of declination of PAL and phenolic contents at biochemical level as a manifestation of increase in bacterial population at the cellular level within the host tissues.

Effect of pesticides application on peanut (Arachis hypogaea L.) associated phosphate solubilizing soil bacteria

In the peanut-growing area of Córdoba, Argentina, herbicides and fungicides utilization is a common practice. This study analyses the effect of pesticides applied at recommended rates on the number and diversity of phosphate solubilizing soil bacteria from this area and the frequency of pyrroquinoline quinone genes (pqq). Pesticide soil treatment did not affect the abundance of culturable phosphate solubilizing bacteria but increased their genetic diversity and altered the frequency of pqqE and pqqC genes. The presence of the pqqE and pqqC genes was observed in a high percentage of isolated Gram-negative phosphate solubilizing bacteria. The analysis of the diversity of 16S rDNA and pqqE genes of soil DNA samples indicated a higher diversity in pesticides treated soil samples compared to control soil samples. Results obtained indicated that pesticides application increases diversity of soil bacterial community and therefore phosphate solubilizing soil bacterial population probably as a result of an increase of bacterial populations that use pesticides applied as carbon and energy source. Analysis of pqq genes frequency and diversity suggested that they would be potential molecular marker of Gram-negative phosphate solubilizing soil bacteria.

Active biodegradable sodium caseinate films manufactured by blown-film extrusion: Effect of thermo-mechanical processing parameters and formulation on lysozyme stability

Sodium caseinate-based edible/biodegradable films containing lysozyme were prepared directly by extrusion processes to obtain antimicrobial films. Thermoplastic pellets containing 1% (w/w) lysozyme were blown by an industrial-like blown-film-extruder to obtain thermoplastic thin films. Lysozyme stability depended mainly on processing temperature and glycerol content. A correct choice of these parameters allowed obtaining pellets and films with 40.8±0.5% and 26.4±0.6% lysozyme residual activity, respectively. Whatever the storage temperature (−20°C or room temperature), lysozyme activity of pellets remained constant for at least 5 weeks of storage. Antimicrobial activity against Micrococcus luteus was assayed in Tryptone Soya Broth (TSB): no bacterial growth was observed for 25h at 37°C in the presence of 0.05g.L−1 pellets, while a 2.4 log increase of bacterial population was observed in the presence of control pellets without lysozyme. Traditional properties of films such as their water sorption and mechanical properties were also investigated and proved that addition of lysozyme at a 1% concentration did not affect these properties as well as their ultimate aerobic biodegradability. The application potential of such edible antimicrobial films is discussed in relation with these properties.