Bacterial Activity Research Articles

Microbial ecology of nitrate-, selenate-, selenite-, and sulfate-reducing bacteria in a H2-driven bioprocess.

A hydrogen (H2)-based membrane biofilm reactor (H2-MBfR) can reduce electron acceptors nitrate (NO3-), selenate (SeO42-), selenite (HSeO3-), and sulfate (SO42-), which are in wastewaters from coal mining and combustion. This work presents a model to describe a H2-driven microbial community comprised of hydrogenotrophic and heterotrophic bacteria that respire NO3-, SeO42-, HSeO3-, and SO42-. The model provides mechanistic insights into the interactions between autotrophic and heterotrophic bacteria in a microbial community that is founded on H2-based autotrophy. Simulations were carried out for a range of relevant solids retention times (SRT; 0.1-20 days) and with adequate H2-delivery capacity to reduce all electron acceptors. Bacterial activity began at an ∼0.6-day SRT, when hydrogenotrophic denitrifiers began to accumulate. Selenate-reducing and selenite-reducing hydrogenotrophs became established next, at SRTs of ∼1.2 and 2 days, respectively. Full NO3-, SeO42-, and HSeO3- reductions were complete by an SRT of ∼5 days. SO42- reduction began at an SRT of ∼10 days and was complete by ∼15 days. The desired goal of reducing NO3-, SeO42-, and HSeO3-, but not SO42-, was achievable within an SRT window of 5-10 days. Autotrophic hydrogenotrophs dominated the active biomass, but nonactive solids were a major portion of the solids, especially for an SRT ≥ 5 days.

Identification of High-Risk Lower Extremity Wounds Using Point-of-Care Test for Bacterial Protease Activity; A Single-Centre, Single-Blinded, Prospective Study.

Clinician observation is the mainstay to determine if wound infection is present, and focuses on presence of erythema, purulence, and odour. However, non-visible bacterial protease activity can delay wound healing and lead to complications. In this study, a point-of-care test to detect the presence of bacterial protease activity (BPA, tested with Woundchek Bacterial Status test) was appraised. A total of 130 patients with lower extremity wounds were recruited in vascular and podiatry clinics, and across two time-points 182 BPA tests were conducted subsequent to initial (blinded) clinician's wound appraisal. Clinical opinion ('no infection', 'possible' or 'definite' infection) and BPA result (negative or positive test) had a moderate Kendall's tau-c rank correlation coefficient of 0.32 (P < 0.001). Binary logistic regression analysis and principal component analysis showed that infection determined by clinical opinion was significantly associated with abovementioned clinical signs and a positive BPA test. However, a positive BPA result was also significantly linked with wound severity, such as number of lesions, chronicity and size. Throughout a 12-week follow-up period, median ulcer size was larger for wounds positive for BPA test at baseline (P 0.001) and week-12 (P 0.036; both Mann-Whitney U-test) respectively. As a pilot initiative, clinical staff were allowed to act on the BPA result if they wished; in 11 out of 71 test-positive cases (15%) this happened and antimicrobial dressing was applied instead of planned standard dressing. These results show that protease-releasing bacteria may be active in ulcers that do not (yet) exhibit hallmark signs of infection, and are associated with delayed healing. Targeted point-of-care testing for bacterial protease activity may have the potential to identify and enable pro-active (antimicrobial) management of these high-risk wounds.

Gallium: a decisive "Trojan Horse" against microorganisms.

Controlling multidrug-resistant microorganisms (MRM) has a long history with the extensive and inappropriate use of antibiotics. At the cost of these drugs being scarce, new possibilities have to be explored to inhibit the growth of microorganisms. Thus, metallic compounds have shown to be promising as a viable alternative to contain pathogens resistant to conventional antimicrobials. Gallium (Ga3+) can be highlighted, which is an antimicrobial agent capable of disrupting the essential activities of microorganisms, such as metabolism, cellular respiration and DNA synthesis. It was observed that this occurs due to the similar properties between Ga3+ and iron (Fe3+), which is a fundamental ion for the correct functioning of bacterial activities. The mimetic effect performed by Ga3+ prevents iron transporters from distinguishing both ions and results in the substitution of Fe3+ for Ga3+ and in adverse metabolic disturbances in rapidly growing cells. This review focuses on analyzing the development of research involving Ga3+, elucidating the intracellular incorporation of the "Trojan Horse", summarizing the mechanism of interaction between gallium and iron and comparing the most recent and broad-spectrum studies using gallium-based compounds with antimicrobial scope.

Geothermal Flora and AgNPs Synergy: A Study on the Efficacy of Lantana camara and Acrostichum aureum-Infused Hand Sanitizers

Hand hygiene is an important factor that needs to be observed in controlling the spread of diseases transmitted through hand-to-hand contact. Synthesis of silver nanoparticles from tembelekan (Lantana camara) and paku laut (Acrostichum aureum) using the green synthesis method has good antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria. Therefore, a preparation formulation was made, namely hand sanitizer, which is still rarely used. Formulations that have successfully entered the evaluation stage include organoleptic tests, homogeneity tests, spreadability tests, adhesion tests, viscosity tests, pH tests, accelerated stability tests, and irritation tests. Antibacterial activity was evaluated against bacteria Staphylococcus aureus and Escherichia coli. The hand sanitizer is formulated to contain 5% tembelekan AgNPs (F1); paku laut AgNPs 5% (F2); and a combination of 2.5% paku laut AgNPs and 2.5% tembelekan AgNPs. The resulting hand sanitizer has good organoleptic characteristics, except for the color of the preparation, which changed during the accelerated stability test. Test results for pH, adhesion, spreadability, viscosity, and homogeneity of hand sanitizer meet the requirements of a good test. Irritation tests on ten volunteers showed no irritation reaction. Antibacterial tests show that hand sanitizer has bacterial antibacterial activity with an average ± standard deviation of the inhibition zone Staphylococcus aureus is 6.605±0.459(F1); 6.665±0.615(F2); 6.380±0.282(F3) dan Escherichia coli namely 6.575 ± 0.219 (F1); 6.860 ± 0.155 (F2); 6.810 ± 0.056 (F3). Making hand sanitizer AgNPs-based ingredients from plants can be used as hand sanitizer, but stabilizers are required to prevent color changes during storage.

Insights into the functional mechanism of the non-specific lipid transfer protein nsLTP in Kalanchoe fedtschenkoi (Lavender scallops)

Plant non-specific lipid transfer protein (nsLTP) is able to bind and transport lipids and essential oils, as well as engage in various physiological processes, including defense against phytopathogens. Kalanchoe fedtschenkoi (Lavender Scallops) is an attractive and versatile succulent. To investigate the functional mechanism of Kalanchoe fedtschenkoi nsLTP (Ka-nsLTP), we expressed, purified and successfully obtained monomeric Ka-nsLTP. Mutational experiments revealed that the C6A variant retained the same activity as the wild-type (WT) Ka-nsLTP. Ka-nsLTP showed weak antiphytopathogenic bacterial activity, but inhibited fungal growth. Ka-nsLTP possessed a hydrophobic cavity effectively binding lauric acid. Our results offer novel molecular insights into the functional mechanism of nsLTP, which broadens our knowledge of the biological function of nsLTP in crops and provides a useful locus for genetic improvement of plants.

Biodegradation Behaviour of the Composite Consisting of Polypropylene and Bauhinia Vahlii Fiber

AbstractThe current study focuses on the degradation rate of polypropylene (PP) and Bauhinia Vahlii (BV) fibers under soil burial and natural weathering conditions for 360 days. The BV‐PP composite was produced with varying BV fiber compositions (0, 10, 20, and 30 wt.%) and 3 % MAPP (Maleic Anhydride Grafted Polypropylene). In addition, MAPP is employed as a coupling agent to improve fiber‐matrix compatibility and promote degradation. The XRD examination shows that a 10 % BV‐PP composite has a crystallinity index of 52.05 %, which is higher than that of neat PP. The rate of biodegradability was investigated using weight loss and tensile properties. The largest degradation was seen in natural weathering conditions with 30 % composite showing the maximum weight loss of 3.8 % and loss in tensile strength and modulus of 16.76 % and 5.11 %, respectively. Simultaneously, no weight loss or drop in tensile characteristics was found in the case of neat PP over 360 days. The SEM images of soil burial show material deterioration, which may be aided by bacterial and fungal activity, whereas natural weathering conditions show a large crack, rougher fracture surface, and cavities, which are attributed to thermal stresses, changes in moisture content, and ultraviolet radiation, thereby promoting the degradation process.

Effects of Dietary Guanidinoacetic Acid on the Performance, Rumen Fermentation, Metabolism, and Meat of Confined Steers.

With the increase in population, it is increasingly necessary to produce food more efficiently. This has expanded the market for additives, which are products that directly (nutritional effect) or indirectly (effect on animal health) favor productivity. Guanidinoacetic acid (GAA) is a natural precursor of creatine. It acts as an energy reserve in skeletal muscle. In addition to being a compound with more significant bioavailability, it is more thermally stable and less expensive than creatine. Therefore, this study aimed to determine whether adding GAA to the cattle diet would alter the meat's composition and fatty acid profile. We used 24 Holstein cattle males (409 ± 5.6 kg), approximately 15 months old, and separated them into four homogeneous groups, one being the control group and three groups with various dosages of GAA in the diets (3.3; 6.6, and 9.9 g/animal/day), for an experimental period of 60 days. Blood, rumen fluid, and animal weighing were performed at three points (days 1, 30, and 60), and daily feed consumption was measured. Steers fed with GAA (9.9 g/d) showed a 16.9% increase in average daily gain (ADG) compared to the control group. These same animals (T-9.9 group) fed with GAA showed a 20% increase in fed efficiency compared to the control group. Lower leukocyte, lymphocyte, and granulocyte counts and lower cholesterol levels were observed in animals that consumed 6.6 g and 9.9 g/d GAA compared to the control group. Animals from the T-6.6 and T-9.9 groups showed 30% and 27.6% reduced bacterial activity in the rumen compared to the control group, respectively. Steers from the T-6.6 and T-9.9 groups fed with GAA showed a 20% and 37% increase in short-chain fatty acids (SCFAs) compared to the control group, respectively. A higher concentration of acetic, propionic, and butyric acids in the ruminal fluid of cattle T-9.9 group was observed at day 60. The two highest doses of GAA showed lower fat levels in the meat, just as the cattle that received 9.9 g/d showed higher levels of total polyunsaturated fatty acids. Complementary data results draw attention to the dose of 9.9 g/d GAA in cattle diets, as anti-inflammatory action can be seen and combined with a higher concentration of SCFAs, consequently increases weight gain. We concluded that consuming this GAA increases the concentration of some unsaturated fatty acids (omegas) in the meat, which adds quality to the product for the consumer.

Enhanced retention of hydrophobic pesticides in subsurface soils using organic amendments

The rapid global population growth since the early 2000s has significantly increased the demand for agricultural products, leading to widespread pesticide use, particularly organophosphorus pesticides (OPPs). This extensive application poses severe environmental risks by contaminating air, soil, and water resources. To protect groundwater quality, it is crucial to understand the transport and fate of these pesticides in soil and sediment. This study investigates the effects of hydrochars and biochars derived from sugar beet shreds (SBS) and Miscanthus×giganteus (MIS) on the retardation and biodegradation of OPPs in alluvial Danube sandy soil. The research is novel in its approach, isolating native OPP-degrading bacteria from natural alluvial sandy soil, inoculating them onto chars, and reapplying these bioaugmented chars to the same soil to enhance biodegradation and reduce pesticide leaching. The amendment of chars with immobilized Bacillus megaterium BD5 significantly increased bacterial abundance and activity. Metabarcoding of the 16S rRNA gene revealed a dominance of Proteobacteria (48.0–84.8 %) and Firmicutes (8.3–35.6 %). Transport modeling showed retardation coefficients (Rd) for OPPs ranging from 10 to 350, with biodegradation rates varying between 0.05 % and 75 %, indicating a positive correlation between retardation and biodegradation. The detection of biodegradation byproducts, including derivatives of phosphin, pyridine, and pyrazole, in the column leachate confirmed that biodegradation had occurred. Additionally, principal component analysis (PCA) revealed positive correlations among retardation, biodegradation, specific surface area (SSA), aldehyde/ketone groups, and bacterial count. These findings demonstrate the potential of biochar and hydrochar amendments to enhance OPP immobilization in contaminated soils, thereby reducing their leaching into groundwater. This study offers a comprehensive approach to the remediation of pesticide-contaminated soils, advancing both our fundamental understanding and the practical applications of environmental remediation techniques.

Survival of the probiotic strain Lacticaseibacillus paracasei subsp. paracasei F19 in high-hopped beers

This study aims to enhance understanding of probiotic lactic acid bacteria (LAB) survival in high-hopped beer formulations and their interactions with different yeasts and highlights the fermentation processes, microbial metabolism, and production of distinctive beer flavors. For this, this research used Lacticaseibacillus paracasei F19 (F19), Saccharomycodes ludwigii, and Saccharomyces cerevisiae strains US-05 (US-05) and Kveik (Kveik) for brewing. Bacterial and yeast cultures were prepared, fermented in wort, and analyzed in different hop concentrations (International Bitterness Units − IBU 0, 20, 40). Methods included physicochemical analysis, yeast and bacterial counts, RT-qPCR for gene expression, statistical analysis, and sensory evaluation by sommeliers following BJCP guidelines. Physicochemical analysis showed efficient fermentation across all hop concentrations (IBU 0, 20, 40), with decreasing SG and pH over time due to lactic acid bacteria and yeast metabolism. Higher hop levels (IBU 20 and 40) resulted in less acidic beer, indicating hop interference with bacterial activity. Yeast populations remained stable regardless of hop content, with Saccharomyces cerevisiae and Saccharomycodes ludwigii performing well. Probiotic strain F19 exhibited robust viability in all formulations. Sensory analysis favored higher hop content beers, suggesting consumer acceptance and potential health benefits of probiotic, high-hop beers. Higher hop content hindered sour beer production as only hop-free beers reached low pH levels. Probiotic strain F19 remained viable under high IBU formulations (20 and 40), with these being preferred by sommeliers using BJCP methodology. All yeast strains supported F19 survival. Further studies are needed on gastrointestinal resistance and clinical benefits.

Formulasi Sabun Cair Berbahan Baku Virgin Coconut Oil VCO dengan Penambahan Ekstrak Daun Pepaya Carica Papaya L. untuk Peningkatan Aktivitas Anti Bakteri Staphylococcus Epidermidis ATCC 12238

Acne is a chronic inflammatory disease caused by Staphylococcus epidermidis. Papaya leaves (Carica papaya L.) contain antibacterial substances, namely alkaloids carpaine, flavonoids, tocophenols. Of this study was to determine the physical quality of liquid soap, increasing antibacterial activity. Papaya leaves were extracted with 96% ethanol solvent, then evaporated with a water bath. Antibacterial activity test using the disc diffusion method in concentrations of 5%, 15% and 25% and liquid soap will be made F0 0%, F1 5%, F2 10%, and F3 25% against Staphylococcus epidermidis ATCC 12238. Amoxicillin tab as a positive control and distilled water as a negative control. Bacterial activity appears a clear zone around the disc paper. And see the physical quality test according to the requirements. The results of the bacterial test data are made in table form, and analyzed using the SPSS method Formula with the addition of papaya leaf extract can be made and according to the physical quality conditions of liquid soap. The results of the 25% concentration extract test are an inhibition zone of 20.8 mm, the highest liquid soap formula is an inhibition zone of 23.8 mm in inhibiting the growth of Staphylococcus epidermidis ATCC 12238. Liquid soap preparations and papaya leaf extract have antibacterial activity against Staphylococcus epidermidis ATCC 12238 bacteria and according to the physical quality requirements of liquid soap.

Miniaturized device to measure urease activity in the soil interstitial fluid using wenner method

This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method. It is developed in the context of biocementation as soil improvement technique, which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity, replacing the use of other binder materials such as cement or resins, and therefore reducing carbon footprint. The microdevice was used to measure urease activity in the soil interstitial fluid, to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry. Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions. The device is basically a squared reservoir printed in polypropylene using a 3D printing machine, incorporating stainless steel electrodes in its base. The electrical resistivity was computed adopting Wenner method, by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied. Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies. The measurements were adjusted during the calibration of the microdevice, done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe. For the bacterial activity measurements, the bacterial and urea solutions were added to a uniform-graded size quarzitic sand (average diameter 0.3 mm) placed inside the microdevice and covering completely the electrodes. Bacterial activity was not affected by the presence of the sand, which confirms that this treatment is effective for this type of soils.

Evaluating the Impact of Ultrasonic Irrigation on Bacterial Levels and Activity Following Chemomechanical Procedures

IntroductionThis single-arm interventional trial aimed to investigate the efficacy of ultrasonic irrigation as a supplementary disinfection approach after chemomechanical procedures (CMP) using molecular techniques based on ribosomal RNA (rRNA) and rRNA genes (referred to as DNA). MethodsSamples were collected from 35 single-rooted teeth with radiographic evidence of apical periodontitis. Samples were taken after gaining root canal access (S1), (S2), and ultrasonic irrigation (S3). DNA-targeted quantitative polymerase chain reaction using universal primers was used to estimate total bacterial levels, while rRNA-targeted quantitative polymerase chain reaction was used to assess bacterial activity. Ratios between rRNA and DNA levels were calculated to search for active bacteria in the samples (rRNA/DNA ≥ 1). Wilcoxon matched-pairs signed-rank test was used to compare the differences in DNA levels between samples and DNA and rRNA levels within samples (P < .05). ResultsDNA-based methods revealed a significant decrease in bacterial levels from S1 to S2 and S2 to S3 (both P < .05). Notably, 11 out of 35 (31.4%) root canals did not harbor bacterial DNA after CMP, whereas ultrasonic activation increased DNA-negative samples to 17 (48.6%). However, all DNA-positive samples were also positive for rRNA, with significantly higher rRNA than DNA levels (P < .05), indicating bacterial activity at the sampling time. ConclusionsUltrasonic irrigation improved the disinfection of root canals after CMP by reducing bacterial levels. However, persisting bacteria remained active in the root canals after CMP and ultrasonic irrigation.

New Arene and/or Heteroarene‐Linked 1,3,4‐Oxadiazoles: Synthesis of Potential Methicillin‐Resistant Staphylococcus aureus and Vancomycin‐Resistant Enterococcus Inhibitors

AbstractBacterial infections, particularly those associated with methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococcus (VRE), threaten public health and economies, with rising antibiotic resistance resulting in more deaths yearly. In this study, we investigated the bacterial inhibitory activity of some new 1,3,4‐oxadiazoles prepared, in good yields, using a two‐step tandem protocol. Therefore, the appropriate N‐benzoylhydrazones were prepared first, then, without isolation, underwent oxidative‐cyclization in the presence of chloramine trihydrate. More 4‐acyloxyphenyl‐linked 1,3,4‐oxadiazoles were prepared by the pyridine‐mediated acylation of 2‐(4‐hydroxyphenyl)‐1,3,4‐oxadiazoles with the appropriate acyl chlorides. Some new products demonstrated good activity, particularly against S. aureus and Enterococcus faecalis strains. The 4‐(5‐(furan‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl)phenyl acetate showed comparable antibacterial activity to ciprofloxacin, with MIC/MBC values up to 3.6/7.2 µM against the previous strains. Moreover, it demonstrated good inhibitory activity against different MRSA and VRE strains when compared to linezolid. It had MIC/MBC values of 7.2/14.4 and 14.4/57.8 µM against MRSA and VRE strains, respectively.

Two marine sulfur-reducing bacteria co-culture is essential for productive infection by a T4-like Escherichia coli-infecting phage

The control of microbiologically influenced corrosion (MIC) challenges the oil exploration sector. The MIC results from electrochemical reactions facilitated by microorganisms such as sulfate-reducing bacteria (SRB), which adhere to the surface of the ducts forming biofilms. SRB uses sulfate as the final electron acceptor, resulting in hydrogen sulfide as the final product, a highly reactive corrosive, and toxic compound. Due to the high diversity of the SRB group, this study evaluated the effect of an Escherichia coli phage, with biofilm degrading enzymes, in preventing biofilm formation by microbial consortium P48SEP and reducing H2S production in a complex SRB community. Three phage concentrations were evaluated (104, 108 and 1012 UFP/ml). High and medium phage concentrations prevented biofilm development, as evidenced by scanning electron microscopy, chemical analysis, and cell counts. In addition, the virus altered the expression pattern of some bacterial genes and the relative abundance of proteins related to biofilm formation and cell stress response. Using a complex culture formed mainly by SRB, it was possible to observe the bacterial growth, H2S, and metabolic activity reduction after the phage was added. This study shows for the first time the ability of an E. coli-infecting phage to prevent the biofilm formation of an SRB consortium and infect and replicate at high concentrations on the non-specific host. This new finding turns the use of non-specific phages a promising alternative for the control of biocorrosion in oil and gas installations, on the other side, alert to the use of large concentration of phages and the influence on bacterial groups with geological importance, opening a research field in phage biology.

Evaluation of physiochemical and in-vitro characteristics of Ixora Coccinea mediated Co3O4 nanoparticles for photocatalytic degradation of toxic textile dye effluents

Discharging colored wastewater from the textile industry into water bodies disrupts the natural ecosystem and reduces the productivity of aquatic life. It is challenging to degrade complex dye molecules, including pathogens and bacteria. This research article deals with the photocatalytic activity of cobalt oxide nanoparticles mediated Ixora coccinea plant extract for industry effluent treatment applications. The green synthesized nanoparticles were found to have high crystallinity and purity, cubic crystal structure, and spherical morphology with 21.5 nm crystallite size. Further, the biological properties, such as antibacterial, antioxidant, and bacterial growth inhibition activity, were evaluated. With 88 % and 83 % bacterial growth inhibition, the antibacterial activity showed a maximum bacterial zone inhibition of 31 ± 0.4 mm for positive and 29 ± 0.3 mm for harmful bacterial strains. Then, the level of scavenging free radicals measured about 93.87 %. The photocatalytic activity was evaluated against the textile dyes under direct sunlight irradiation. The maximum dye degradation was achieved for Alizarin red (85.2 %), Crystal violet (90.7 %), Reactive black (94.5 %), and Rhodamine B (96.4 %) dyes at the end of 90 min of irradiation. Moreover, this research paper introduces a method for creating cobalt nanoparticles using natural and sustainable approaches. These nanoparticles have potential in several fields, such as medicine, catalysis, and water remediation.

Development of calcium phosphate cement composed of silica-modified hydroxyapatite, cerium oxide, and silica as an osteoporotic bone filler

Calcium phosphate cement (CPC), composed of silica-modified hydroxyapatite (HA-SiO2), cerium oxide (CeO2), and silica (SiO2), was developed as an osteoporosis bone filler. The effect of CeO2 and SiO2 content on the CPC's properties, such as crystal parameters, surface properties, antibacterial activity, and toxicity properties, were studied. HA-SiO2 was prepared using the sol-gel method, while CeO2 was prepared using the precipitation method. HA in HA-SiO2 has crystal properties similar to pure HA. Synthesized CeO2 contains Ce3+ and Ce4+ ions with Ce3+/Ce4+ = 0.34. Computational calculation predicted that the CeO2 (111) surface and glycine molecule interaction was categorized as chemisorption. Moreover, CeO2 has antibacterial activity toward Escherichia coli and Staphylococcus aureus. Combining HA-SiO2 and CeO2 did not change the adsorption-desorption isotherm curve type, but slightly decreased the surface area, total pore volume, and average pore. Increasing the percentage of CeO2 and adding 10 % SiO2 (w/w) affected the particle's size and CeO2 distribution. However, CPC lost antibacterial activity toward Staphylococcus aureus but adding 10 % SiO2 (w/w) increases the bacterial activity toward Escherichia coli close to that of pure CeO2. The MTT assay using pre-osteoblast MC3T3E1 cells showed that the CPC has IC50 = 4227 μg/ml or is nontoxic.

Integration of batch assays and microbial community analysis for partial nitritation and anammox process monitoring

This study investigates the feasibility of using batch assays combined with microbial community analysis to control the partial nitritation/anammox (PN/A) process. A Moving Bed Sequencing Batch Biofilm Reactor (MBSBBR) was operated over 130 days with varying ammonia influent concentrations. The highest anammox activity (22.4 mg N/gVSS∙h) was observed at an influent concentration of 200 mg N-NH4/L, correlating with high total inorganic nitrogen (TIN) removal efficiency. However, increasing the ammonia influent concentration to 340 mg N/L led to decreased anammox and nitrifying bacteria activities and reduced TIN removal efficiency. Sequencing revealed Candidatus Brocadia as the predominant genus, with its abundance correlating with TIN removal performance. High correlation coefficients (above 0.76) among batch tests highlighted the interdependence of key bacterial activities in the PN/A, emphasizing the need for a balanced microbial community for effective nitrogen removal. Batch assays provided immediate data on metabolic activities, while sequencing offered comprehensive insights into microbial community structure. Integrating these methods allowed for a holistic understanding of the microbial dynamics and their impact on process stability. This approach enhances the accuracy of wastewater treatment monitoring, aiding in the development of effective management strategies for optimizing PN/A processes.

Effect of long-term liquid dairy manure application on activity and structure of bacteria and archaea in no-till soils depends on plant in development.

This study aimed to evaluate the impact of long-term liquid dairy manure (LDM) application on the activity and structure of soil bacterial and archaea communities in two cropping seasons over 1year of a no-till crop rotation system. The experiment was run in a sandy clay loam texture Oxisol, in Brazil, including LDM doses of 60, 120, and 180 m3ha-1year-1, installed in 2005. Soil sampling was conducted during spring 2018 and autumn 2019 at 0-10-cm depth. Microbial biomass carbon and nitrogen, 16S rRNA gene sequencing, microbial respiration and quotient were performed. Over the 14-year period, LDM application increased soil microbial community activity. Analysis of 16S rRNA gene sequencing revealed dominance by Proteobacteria, Acidobacteria, and Actinobacteria phyla (67% in spring and 70% in autumn). Genera Pirulla and Nitrososphaera showed enrichment at LDM doses of 120 and 180 m3ha-1year-1 doses, respectively. During spring, following black oat cropping, shifts in the relative abundance of Bacteroidetes, Proteobacteria, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Chloroflexi, Actinobacteria, and AD3 phyla were observed due to LDM application, correlating with soil chemical indicators such as pH, K, Ca, Mn, and Zn. Our findings indicate that plant development strongly influences microbial community composition, potentially outweighing the impact of LDM. Our findings indicate that the application of liquid dairy manure alters the soil bacterial activity and community; however, this effect depends on the developing plant.

Nanoplasmonic Rapid Antimicrobial-Resistance Point-of-Care Identification Device: RAPIDx.

The emergence of antibiotic resistance has become a global health crisis, and everyone must arm themselves with wisdom to effectively combat the "silent tsunami" of infections that are no longer treatable with antibiotics. However, the overuse or inappropriate use of unnecessary antibiotics is still routine for administering them due to the unavailability of rapid, precise, and point-of-care assays. Here, a rapid antimicrobial-resistance point-of-care identification device (RAPIDx) is reported for the accurate and simultaneous identification of bacterial species (genotype) and target enzyme activity (phenotype). First, a contamination-free active target enzyme is extracted via the photothermal lysis of preconcentrated bacteria cells on a nanoplasmonic functional layer on-chip. Second, the rapid, precise identification of pathogens is achieved by the photonic rolling circle amplification of DNA on a chip. Third, the simultaneous identification of bacterial species (genotype) and target enzyme activity (phenotype) is demonstrated within a sample-to-answer 45min operation via the RAPIDx. It is believed that the RAPIDx will be a valuable method for solving the bottleneck of employing on-chip nanotechnology for antibiotic-resistant bioassay and other infectious diseases.

In vitro antimicrobial and antibiofilm activity of phage cocktail against Mammaliicoccus sciuri, a causative agent of bovine mastitis.

In this research paper the in vitro antimicrobial and antibiofilm activity of phage cocktail against the coagulase negative Mammaliicoccus sciuri was investigated. Three M. sciuri isolates obtained from clinical bovine mastitis samples were characterized and identified by 16S rRNA gene sequencing. Bacteriophages with lytic activity against M. sciuri isolates were isolated from dairy farm effluents. Two typical phages were isolated using standard enrichment and plaque assay techniques, purified by polyethylene glycol precipitation, and morphologically characterized based on shape and size using transmission electron microscopy. This was followed by determination of host range using spot tests and stability to varying temperature, pH and UV treatment. The phage cocktail suppressed bacterial activity within 30 min of exposure. Crystal violet assay showed that the tested phages and their cocktail significantly reduced the biofilm biomass of all three M. sciuri strains compared to the untreated control in vitro within 24 h with a single dosing. Transmission electron micrography of the purified phage particle revealed an icosahedral head and a rigid contractile tail, characteristic of the class Caudoviricetes. The findings open new avenues in phage-based antimicrobial approaches for controlling contagious and teat skin opportunistic bacteria causing bovine mastitis.