Microbial Content Research Articles

Uji Total Mikroba, Kadar Air, dan pH Ikan Nila (Oreochromis niloticus) Dengan Perendaman Ekstrak Belimbing Wuluh (Averrhoa bilimbi L) Selama Penyimpanan Suhu Ruang

Tilapia fish are susceptible to the process of decay, within 2 hours after death the tilapia fish will experience a decline in physical quality. Starfruit extract contains active compounds, namely saponins, triterpenoids and several minerals which are antibacterial substances. This research aims to determine the effect of starfruit extract on the total microbial test, water content and pH of tilapia during room temperature storage. Data analysis used a Completely Randomized Design (CRD). Data were analyzed descriptively for total microbial testing using the Indonesian National Standard calculation method SNI 2332.3-2015 and SNI 01-2346-2006. The differences in treatment in this study were made by differences in the concentration of starfruit extract. The concentration of starfruit juice given was 0 gr (P1), 40 g (P2), 60 gr (P3), 80 gr (P4) and 100 gr (P5) with four repetitions. The samples were then stored at room temperature for 8 hours. Based on the research results, it can be seen that starfruit extract has an influence on the total microbial value, Based on the research results, it can be seen that starfruit extract has an influence on the total microbial value, pH value and water content value of tilapia fish. The number of bacterial colonies in the treatment with the highest amount of extract (100 grams) with the lowest total microbial value was 2.49 x 105 colonies/g. Also, the pH value and water content of all treatments given starfruit extract were still included in the standards for fresh fish.
 Keywords: Tilapia, Wuluh Starfruit, Total Microbes

Soil Microbial Community and Their Relationship with Soil Properties across Various Landscapes in the Mu Us Desert

Soil microorganisms play crucial roles in maintaining material circulation and energy flow in desert ecosystems. However, the structure and function of soil microorganisms in different forestlands are currently unclear, restricting the use of sand-fixing plants and the understanding of forest ecosystem functions. In this study, Artemisia ordosica, Caragana korshinskii, and Salix psammophila, three types of sand-fixing forests widely distributed in the Mu Us Sandy Land, were used to explore the effects of sand-fixing forests on soil physicochemical properties, soil enzyme activity, soil microbial biomass, microbial community structure, and inter-microbial species relationships. Soils of forestlands showed higher soil organic carbon (SOC), total phosphorus (TP), and total nitrogen (TN) contents than bare sandy land. The SOC in bare sandy soil was only 0.84 g kg−1, while it remained 1.55–3.46 g kg−1 in forestland soils. The TN in bare sandy land soil was 0.07 g kg−1, which was significantly lower than that in forestland soils (0.35–0.51 g kg−1). The TP in bare sandy soil was 0.18 g kg−1, significantly lower than that in forestland soils (0.46–0.69 g kg−1). Afforestation of bare sandy land improved soil microbial carbon and nitrogen contents and increased microbial enzyme activities of acid phosphatase and N-acetyl-β-D-glucosaminidase. Significant differences were observed between the three forestlands and bare sandy land in terms of soil microorganisms and community composition. With the establishment of a sand-fixing forest, the alpha diversity of soil bacteria significantly improved, whereas that of soil fungi remained stable. The bacterial community comprised 33 phyla, 106 classes, 273 orders, 453 families, and 842 genera. While five fungal phyla were detected by OTUs at a similarity of 97%, bacterial and fungal community structures were affected by the organic carbon content, sand particle content, soil pH, total nitrogen, and total phosphorus contents of soils. This study is helpful for vegetation construction and protection on sandy lands from the perspective of plant-microbe interactions.

Microbial traits dictate soil necromass accumulation coefficient: A global synthesis

AbstractAimThe accumulation of microbial necromass carbon has gained increasing attention due to its slow decomposition. However, it remains unclear what induces the accumulation of microbial necromass carbon via reiterated community turnover on large spatial scales. This study explores the characteristics of soil necromass carbon accumulation in terrestrial ecosystems.LocationGlobal.Time PeriodContemporary (1999–2022).Major Taxa StudiedSoil microorganisms.MethodsA dataset was compiled using 993 observations from 82 peer‐reviewed papers on the effects of coefficients of microbial necromass accumulation (hereafter NAC) in equilibrium. Linear mixed‐effect models and structural equation models were used to ascertain the controlling factors of the NAC.ResultsThe average NAC was higher in croplands (28.2) and forests (26.8) than in grasslands (21.1). Edaphic factors seemingly affected the NAC, which was lower in soils with high pH and clay content on a global scale. Biotic factors, particularly those related to living microorganism abundance and microbial biomass nitrogen content, were the pivotal drivers of NAC and accounted for approximately 43.6% of its geographic variability. More organic carbon was likely to be preserved in soil with a higher NAC, regardless of ecosystem type.ConclusionsNovel findings regarding the overriding controls for the living microorganism abundance and microbial biomass nitrogen that drive the NAC highlight an urgent need for viable strategies to manipulate microbial attributes for enhancing carbon sequestration.

Organic amendments perform better than inorganic amendments in reducing the absorption and accumulation of cadmium in lettuce.

The main purpose of applying organic or inorganic amendments is to guarantee crop safe production in heavy metal contaminated soil. However, previous studies showed that the effects of organic or inorganic composite amendments on the cadmium (Cd) concentration of lettuce (Lactuca sativa var. ramosa Hort) were inconsistent. Accordingly, a sixty-day pot experiment was carried out to examine the impacts of the inorganic materials (lime, L and zeolite, Z), organic materials (biochar, B and compost, C), and their combination on the immobilization of Cd in soil and its uptake by lettuce. The objective was to identify the most suitable soil amendment combination that promotes safe lettuce production. The results revealed that the combined application of BC, LZC, and LBC significantly increased the plant height by 11.09-28.04% and fresh weight by 183.47-207.67%. This improvement can be attributed to enhanced soil quality, such as increased dissolved organic carbon (DOC) by 70.19-80.42%, soil respiration (SR) by 29.04-38.46%, and soil microbial carbon content (SMC) by 36.94-46.63%. Compared to inorganic fertilizers and their combination with organic amendments, organic amendments had a significant impact on reducing shoot Cd concentration by 33.93%-56.55%, while increasing the activity of catalase by 138.87-186.86%. And soil available Cd measured by diffusive gradients in thin-films (DGT-Cd) decreased 24.73-88.13% in all treatments. Correlation analysis showed that plant Cd concentration was significantly correlated with soil pH, SR, cation exchange capacity (CEC), DOC and SMC. These results demonstrated that organic amendments, especially the combination of biochar and compost, have greater potential than inorganic amendments and inorganic-organic combinations for realizing safe production of lettuce and improving soil quality in the Cd moderately contaminated acid farmland.

Thirst for Knowledge: Exploring Dubai's Water Quality through a Public Health Lens

The current study aimed to evaluate the biochemical quality of both bottled water and tap water in the Emirate of Dubai. A total of sixty samples were collected (6 Brand x 10 samples each), while an additional 10 samples were taken from the tap water source. The analysis results were then compared to international standards established by IBWA, FDA, USEPA, WHO, and Abu Dhabi's specific standards. The objective was to identify any potential risks or hazards to public health arising from chemical or biological contaminants in the water. The study assessed various parameters, including total alkalinity, total hardness, and heavy metals, all of which were found to fall within international limits. Microbial content was also analyzed and compared to various standards. The results of this analysis demonstrated that the water's composition met the international norms for safe drinking water. To investigate the impact of different sodium concentrations on blood tonicity, a qualitative microscopic assessment was employed. The results revealed that sodium concentrations exceeding 3mg/L rendered the cells hypertonic. Any further increase in sodium concentration beyond this level directly correlated with increased cell hypertonicity. However, further research is required to delve into other critical aspects of water consumption in the UAE, such as public attitudes toward water and the influence of water pricing on residents' purchasing choices. Public awareness campaigns are essential to rectify misconceptions about both tap water quantity and bottled water quality.

The provenance of microorganisms adapted to extreme salinity, extreme temperature, and toxic metals within the Montney shale formation.

Introduction Shale oil reservoirs are hypothesized to be sterile due to the extremely high temperature, pressure and salinity within these formations (Evans et al. 2018). High concentrations of toxic metals also pose challenges that demand specific microbial adaptions (Boyd and Barkay 2012, White and Gadd 1998, Ben Fekih et al. 2018). While some microorganisms are introduced into and are selected for within shale formations during hydraulic fracturing, the possibility that certain microorganisms are pre-existing inhabitants of these formations is less clear. Here, we followed the microbial diversity of input and output fluids injected into a Montney formation shale reservoir to assess the distribution and transport of microbial populations during hydraulic fracturing. Enrichment cultures distinguished various metabolisms in the microbial populations found in different sample types, and adaptations allowing them to colonize such niches. Material and methods Fracturing fluid, drilling muds (3302 m, 3350 m and 3400 m depths), shale cuttings (rinsed from the drillings muds), shale core plugs and produced water samples (12-month period) were sampled from a Montney shale oil reservoir. Microbial community compositions were analyzed by amplicon sequencing. Metal content was analyzed by inductively coupled plasma-mass spectrophotometry. High salinity enrichments at 90°C of the drilling muds or rinsed shale samples were set up in triplicate and amended with glucose and guar gum (a mannose/galactose-based polymer used during hydraulic fracturing). Sugars were measured through spectrophotometric assays. Metagenomic analyses were performed to assess microbial gene content. Results/Discussion Provenance of microorganisms from the Montney shale formation Provenance of microorganisms from the Montney shale formation Input fluids (fracturing fluid, drilling muds) were revealed to be the likely source of most of the microbial diversity. However, some microorganisms were only detected in the subsurface samples. ASVs affiliated with Aurantimonas, Caminicella, BRH-c8a (Family Desulfallas) and Geotoga exhibited occurrence patterns consistent with being derived from subsurface shale formations. Geotoga has only ever been reported from oil reservoirs (Semenova et al. 2020). Analysis of produced water revealed ASVs from these groups increasing in abundance during hydraulic fracturing operations, suggesting selective pressure from oil reservoir conditions (e.g., toxic metal presence, input of saline water, temperature and pressure fluctuations). Incubations set up from drilling muds showed a preference for glucose while incubations of the rinsed shale cuttings showed a microbial preference for guar gum (i.e., mannose production; Fig. 0), reinforcing the presence of different populations being derived from surface and subsurface samples. Adaptations for life in Montney shale Adaptations for life in Montney shale When considering adaptations of microorganisms for environmental conditions found in oil reservoirs, it is relevant to note the presence of toxic metals such as arsenic, cadmium and mercury. Levels of all three metals were found to vary over time within the 28-day shale microbial enrichments and 12-month produced water time course analyses (Suppl. material 1). Metagenomics revealed various genes for the internalization and metabolism of all three metals within the shale microbiome (i.e., arsenate reductases, arsenite transporters, metallothioneins, mercuric reductases). In conclusion, the results of this study suggest that shale reservoirs thus might not be sterile environments, and host microorganisms are able to contend with major perturbations.

Biochar-based organic amendments on soil health, nutrient status and quality of potato (Solanum tuberosum)

Cultivation of quality potatoes ensures a good earning compared to low quality, especially in terms of tuber weight and starch content. Therefore, an experiment was laid out to find out the impact of an organic amendment based on the combinations of biochar, vermicompost, poultry manure, and bone meal for the enrichment of soil health and quality of potato crops at the research farm of Lovely Professional University, Punjab. The parameters of pH, EC, organic carbon, soil microbial biomass, nitrogen, phosphorus, potassium, labile carbon, and particulate organic carbon (POC) were used to understand the soil health improvement, while starch content and grading systems ranging from A to C were used for the quality of the potato. Among the treatments, most of the parameters were recorded as statistically significant at p>0.05. The highest improvement in terms of pH, EC, organic carbon, soil microbial biomass, nitrogen content, labile carbon, and particulate organic carbon (POC) was recorded in T3 (7.58, 0.39 dSm-1, 0.53 %, 333.3 µg g-1, 198.3 kg ha-1, 3.71 and 7.0 g kg-1 of soil) compared to T0 (7.38, 0.32 dSm-1, 0.44 %, 325.33 µg g-1, 171.5 kg ha-1, 2.33 and 3.0 g kg-1 g kg-1), while the phosphorus and potassium contents were estimated highest in T2 (17.4 and 255 kg ha-1). The quality parameters like starch content and grading quality of potato tubers were also influenced positively and estimated significantly highest in T3 (53.60 % and 153.7 q ha-1 of A grade potato). This study has shown the potential to improve the quality of potato tuber by providing a desirable soil environment to coordinate with potato plants.

Effects of microbial fertilizer and irrigation amount on growth, physiology and water use efficiency of tomato in greenhouse

A pot experiment was conducted to investigate the effect of microbial fertilizer and irrigation regime on growth, physiology, water use efficiency (WUE) of tomato plants and soil nutrients. Microbial fertilizers: bacillus subtilis fertilizer (B.s.), bacillus polymyxa fertilizer (B.p.) and combined bacillus species (B.c.) were used as microbial fertilizers in the study, and plants treated without bacillus fertilizer were taken as control (CK). Three irrigation levels were set, i.e., full irrigation (I1) which plants were irrigated to 95 % field capacity (θf), and two deficit irrigations which were 2/3 I1 (I2) and 1/3 I1 (I3), respectively. The result showed that microbial fertilizers enhanced leaf photosynthesis rate (An), transpiration rate (Tr), relative chlorophyll content (CHL), nitrogen index balance (NBI) and leaf water potential (Ψl) in addition to increased plant root length, root surface area, root volume; and promoted plant water consumption, dry matter (DM) and plant water use efficiency (WUE). The content of nitrogen in leaf ([N]leaf), nitrogen use efficiency (NUE), the mineral nitrogen and soil microbial nitrogen content (MBN) were significantly improved by microbial fertilizer. Compared to CK, B.s., B.p. and B.c. increased An by 17.96 %, 11.77 % and 6.83 %, respectively. B.s. fertilizer significantly increased MBN and root length by 21.99 % and 55.08 % than CK. Deficit irrigations decreased An, Tr, stomatal conductance (gs), and improved intrinsic water use efficiency (WUEi) and instantaneous water use efficiency (WUEinst). Deficit irrigation depressed leaf area, Ψl, CHL, NBI, root length, root surface area and root volume, hereby declined plant water consumption, and optimized plant WUE. In this study, microbial fertilizers mitigated negative effects of deficit irrigation on photosynthesis and DM and improved WUE. Compare to CK and other microbial fertilizers, B.s fertilizer treated plants possessed enhanced plant water status, higher leaf gas exchange rates, more developed root system, higher plant nitrogen accumulation and NUE. Hereby, the B.s. fertilizer is an optimal strategy to mitigate water stress in tomato plants and promoted plants growth.

Study on the physiochemical and microbial content of drinking water in and around Al-Nasiriyah province

Objective: To identify microbial contents of water by physical and chemical analysesin different regions in a Middle East country.Methods: The prospective, cross-sectional study was conducted in and around Al-Nassirya province ofIraq from March to July 2021, and comprised drinking water samples taken from water stations in citycentre as well as Al-Dawaya, Al-Shatrah and Al-Nasr districts in the outskirts. Analysis included estimationof turbidity, temperatures, potential of hydrogen, total hardness, and estimation of chlorine, calcium andsodium measured in The-Qar university laboratories, Data was analysed using SPSS version 17. T-test wasused to compare the mean values. A p-value of Less than or Equal to 0.05 was considered significant.Results: Of the 10 water samples 1(10%) was collected from the city centre, 4(40%) from Al-Dawaya district,2(20%) from Shatra district and 3(30%) from Al-Nasr district. Significant differences were found in thesamples collected from city centre compared to those from the countryside (p<0.29). Turbidity was less(1.7) in samples from the city centre compared to the three countryside water stations. High levels ofchlorine (26), concentration of calcium (199) and sodium (479) were moderately high in samples fromAl-Nasiriya city. Microbial growth was detected in samples from Al-Nasr and Al-Dawaya districts whereEscherichia coli, staphylococcus aureus and cryptosporidiumparrum were detected in some water stations.Conclusion: Countryside water stations showed changes in standard physiochemical normal values andcontamination of drinking water with microorganisms.Keywords: Chlorine, Cryptosporidium parvum, Staphylococcus aureus, Cryptosporidiosis,Cryptosporidium, Escherichia coli, Sodium.

Microbiological assessment of the state of urban soils of the oil and gas region on the example of the territory of Kogalym

In the course of this work, the total numbers of heterotrophic microorganisms and the numbers of microbes participating in the nitrogen cycle (ammonifying, denitrifying, nitrifying and nitrogen-fixing ones) in urban and natural (background) soils of Kogalym were estimated. A relation between the obtained results with geochemical indicators was revealed. Our microbiological analysis showed the predominance of nitrogen-fixing microorganisms in urban soils (5.0×104 – 2.0×106 CFU/g of soil), which were on average 44 less than in natural soils. In the last ones the average number of denitrifying microorganisms was 7.0×104 CFU/g of soil, exceeding 1.3 times their number in urban soils. Based on the information obtained, microbial contents in the soils of Kogalym were established as a row: nitrogen fixators > ammonifiers > heterotrophs > denitrifiers; in background samples: denitrifiers > ammonifiers > heterotrophs > nitrogen fixators. According to the data of ecological and geochemical analysis, an excess of the MPC of mobile forms of heavy metals, such as Cu, Ni and Zn, was revealed in the Eastern Industrial zone of the city. A significant inverse correlation was revealed between the number of denitrifying microorganisms in the Kogalym soil microbiocenoses and the content of mobile Ni and Cu forms, which points to a possible negative effect of these metals on the development of denitrifiers. The minimum number of ammonifying, denitrifying and nitrogen-fixing microorganisms was found in the Eastern Industrial zone, especially in the soil samples that were taken near the railway. On the whole, the absence of noticeable differences in the microorganisms` content of the studied groups in urban and natural soils indicates a low level of soil pollution in Kogalym. The obtained results represent the basis for subsequent ecological monitoring of the soils in the city and adjacent oil-producing areas, forecasting the environmental consequences of anthropogenic activities in these territories.

Comparison of Antimicrobial Activity of Injectable Platelet-Rich Fibrin (i-PRF) and Leukocyte and Platelet-Rich Fibrin (l-PRF) Against Oral Microbes: An In Vitro Study.

Aim Injectable platelet-rich fibrin (i-PRF) and leukocyte and platelet-rich fibrin (l-PRF) are both blood-derived products used in regenerative medicine and dentistry. They contain platelets, growth factors, and leukocytes, which can have antimicrobial properties to some extent, but their primary purpose is tissue regeneration and wound healing. i-PRF and l-PRF may have some indirect antimicrobial properties due to their composition and ability to enhance tissue healing and immune responses, and they are primarily used in dentistry for their regenerative and wound healing capabilities rather than as standalone antimicrobial agents. This study aims to compare the anti-microbial activity of i-PRF and l-PRF against oral microbes. Methodology This study included 30 patients who were selected using G*Power software version 3.1 (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany) calculation with the population size. The plaque samples were collected from the subjects using area-specific Gracey curettes used for scaling and root planing to remove plaque and calculus from the teeth and root surfaces. The collected plaque samples were transferred to a tube containing 5 ml of saline (sterile saltwater). The purpose of using saline is to preserve the microbial content of the plaque sample without altering the microbial composition. To obtain a uniform solution, the samples in the saline-containing tube were vortexed for 5 minutes. After vertexing, a small amount of the suspension (0.1 ml) was taken for further analysis. The 0.1 ml suspension was used to plate blood agar using the streak method. A loop or needle is used to streak the sample back and forth across the surface of the agar, leading to the dilution and separation of the bacteria. Results Results state that i-PRF has a maximum zone of inhibition (2.19±0.47 mm) when compared with metronidazole (0.14±0.09 mm). It can be stated that platelet concentrates demonstrate better antimicrobial activity due to their higher oxygen metabolites which help in the aggregation and internalization of microorganisms, which enhances the clearance of pathogens from the bloodstream. Paired t-test has been used for the comparison between the two groups, and the p-value is >0.05 stating that the difference is statistically significant. Conclusion The present study states that i-PRF demonstrated better antimicrobial efficacy as compared to l-PRF. Hence, i-PRF helps in reducing microbial load at the periodontally infected sites when compared with l-PRF.

Use of the Azoll plant (Azolla pinnata) in Broiler Diets and its effect on the Microbial Content of the Intestine and Carcass Characteristics

أجريت هذه الدراسة في حقل الدواجن التابع لقسم الانتاج الحيواني -كلية الزراعة والغابات - جامعة الموصل، استخدمت افراخ فروج لحم غير المجنسة بعمرٍ يوم واحد (Ross 308) ومن اليوم الاول لاستلام الافراخ وزعت عشوائيا على معاملات الدراسة والتي تمثلت بإضافة ثلاثة نسب مختلفة من الازولا المجففة نوع بيناتا( Pinnata.A ) الى العليقة وبواقع ثلاثة مكررات/معاملة وكما يلي:- T1 (control ): عليقة قياسية خالية من الازولا T2: عليقة قياسية +4.5 % ازولا T3: عليقة قياسية9.0+ % ازولا T4: عليقة قياسية+13.5 % ازولا كانت نتائج التحليل الإحصائي: انخفاض في اعداد السالمونيلا والايكولاي ونسبة الرقبة ودهن البطن مع زيادة معنوية في اعداد اللاكتوباسلس ونسبة الافخاذ والظهر وطول الامعاء والاعورين عند اضافة الازولا بنسبة (9.0،13.5)% مقارنة بالسيطرة وعدم وجود فروق معنوية في وزن الذبيحة المجهزة ونسبة التصافي والاحشاء المأكولة بين المعاملات وكان الهدف من الدراسة هو اضافة الازولا المجففة باحلال جزء من بروتين العليقة كوسيلة ادارية تغذوية متبعة لاستخدام مصدر بروتيني متاح محلياً.

Consumers’ safety of some selected ready to eat and street vended foods in Wudil, Kano state as determined by microbial content

Because of their cost, affordability, availability and simplicity to prepare, ready-to-eat foods are highly consumed in all over Nigeria, therefore critical to Nigerians’ health. This research aimed at ascertaining the consumers’ safety in terms of microbial load in ready-to-eat sell on the street Awara (Steamed Cowpea Beans Slurry) and Moin-moin (Bean pie) sold in three different vending locations retailed to the students of Aliko Dangote University of Science and Technology Wudil, Kano state Nigeria. Total of 24 samples consisting of equal quantity of Awara (Bean pie) and Moin-moin (Steamed Cowpea Bean Slurry) were collected from three different location in Wudil town and analyzed for total aerobic bacteria, fungi and Staphyococcus count. Seven different species of microorganism of health concern were identified to include Micrococcus spp, Staphylococcus aureous, Bacillus spp., Klebsiella spp., Mucor, Rhizophus stoonifer and Aspergillus flavus. The total mean of the aerobic bacteria, fungi and Staphylococcus count across all the location in all the samples were found to be withing the tolerable range with the standard set by the International Commission for Microbial Specification for Foods (ICMSF) and Food and Environmental Hygiene Standard (FEHD) as well as the South Wales Food Authority Standards for ready-to-eat foods. Higher microbial counts were founds on Moin-moin sample and this may be attributed to its high moisture content which is found to range from 64.2 to 70.0 %. The comparison of this research finding with international standard justified the safety of consumers and concludes the acceptability of these foods as safe to eat even though the presence of microorganisms such as Aspergilus spp. has been found to pose serious public health issue such as aflatoxin intoxication

Quantitative investigation of the bacterial content of periodontal abscess samples by real-time PCR

ObjectivesPeriodontal abscesses, which are part of the acute periodontal disease group characterized by the destruction of periodontal tissue with deep periodontal pockets, bleeding on probing, suppuration, and localized pus accumulation, cause rapid destruction of tooth-supporting tissues. This study aimed to evaluate the microbial content of periodontal abscesses by specific and culture-independent qPCR. MethodsThis study was conducted on 30 volunteers diagnosed with periodontal abscesses and presenting with complaints of localized pain, swelling, and tenderness in the gingiva. Genomic DNA was isolated from the samples taken. Escherichia coli bacteria were used for the standard curve created to calculate the prevalence of target bacteria in the total bacterial load. 16S rRNA Universal primers were used to assess the total bacterial load and prevalence. Bacterial counts were analyzed with Spearman's rank correlation coefficients (ρ) matrix. ResultsFrom the analysis of Real-Time PCR, Porphyromonas gingivalis (30, 100%), Prevotella intermedia (30, 100%), and Fusobacterium nucleatum (30, 100%) were detected in all samples. Campylobacter rectus (29, 96.6%), Porphyromonas endodontalis (29, 96.6%), Tannerella forsythia (28, 93.3%), Filifactor alocis (28, 93.3%), and Actinomyces naeslundii (28, 93.3%) were also frequently detected. ConclusionsPeriodontal abscesses were found to be polymicrobial, and not only periodontal pathogens appeared to be associated with the development of periodontal abscesses. The presence, prevalence, and number of Porphyromonas endodontalis and Propionibacterium acnes in the contents of periodontal abscesses were determined for the first time in our study. Further studies are needed to better understand the roles of bacteria in periodontal disease, including abscesses.

Increasing plant species diversity enhances microbial necromass carbon content but does not alter its contribution to soil organic carbon pool in a subtropical forest

Increasing plant species diversity benefits soil organic carbon (SOC) accumulation in forest ecosystems, but how microbial necromass contributes to SOC accumulation in response to plant species diversity and the underlying mechanisms have not been well explored. In the present study, 45 plots covering a natural gradient of plant species diversity as indexed by Shannon's diversity index from 0.15 to 3.57 were selected in a typical subtropical forest with calcareous soil. Soil microbial necromass C including fungal necromass C and bacterial necromass C was estimated using amino sugars, with multiple soil biotic and abiotic variables being determined to explore the mechanisms underlying the effects of plant species diversity on microbial necromass C. Total microbial necromass C contents ranged from 4.28 to 85.7 g kg−1 soil with an average of 36.3 ± 17.6 g kg−1 soil, and accounted for 54.2% ± 22.2% of the SOC pool across the 45 plots. Fungal necromass C had a greater contribution to SOC than bacterial necromass C. Increasing plant species diversity was significantly and positively correlated with microbial necromass C content, but was not significantly related to the contribution of microbial necromass C to the SOC pool. Though increasing plant species diversity enhanced microbial biomass via stimulating C use efficiency and substrate availability, microbial biomass was not significantly linked to microbial necromass C accumulation. Instead, increasing plant species diversity benefited microbial necromass C accumulation via enhancing the mineral protection due to its positive effect on soil exchangeable calcium. Due to the proportionate increase of microbial necromass C and SOC, and the unaltered soil C:N ratio and C:N imbalance between soil organic matter and microbial biomass, the contribution of microbial necromass C to the SOC pool was not affected by plant species diversity. Our study highlights the key role of mineral protection in soil microbial necromass C accumulation, and provides a microbe-dependent linkage between plant species diversity and SOC accumulation.

Spatial Heterogeneity of Total and Labile Soil Organic Carbon Pools in Poplar Agroforestry Systems

Agroforestry systems are considered effective methods of carbon sequestration. In these systems, most of the carbon is stored in the soil, and the pattern of tree planting can influence the spatial distribution of organic matter input into the soil. However, limited information is available about the extent of this influence. In this study, the horizontal and vertical distributions of soil organic carbon (SOC) and labile fractions were investigated in four planting systems: a pure poplar (Populus deltoides cv. “35”) planting system, a wide-row (14 m spacing) poplar and wheat (Triticum aestivum L.) agroforestry system, a narrow-row (7 m spacing) poplar and wheat agroforestry system, and a pure wheat field. The results showed that although the poplar system had the highest vegetation biomass (147.50 t ha−1), the agroforestry systems overall had higher SOC contents than the pure poplar system and wheat fields. Especially in the wide-row agroforestry system, the SOC, readily oxidizable carbon, and dissolved organic carbon contents were, respectively, 25.3%, 42.4%, and 99.3% higher than those of the pure poplar system and 60.3%, 148.7%, and 6.3% higher than those of the wheat field in a 1 m soil profile, and it also had the highest fine root biomass. However, the microbial biomass carbon content was highest in the pure poplar system. The SOC of the three poplar planting systems was spatially heterogeneous, with the highest values occurring at 1.5 m in the narrow-row systems and within the tree rows in the wide-row system, similar to the distribution of fine root biomass. Additionally, we found that the larger the diameter at the breast height of the trees, the greater their positive effect on SOC at greater distances.

Elevated CO2 reduced antimony toxicity in wheat plants by improving photosynthesis, soil microbial content, minerals, and redox status.

Antimony (Sb), a common rare heavy metal, is naturally present in soils at low concentrations. However, it is increasingly used in industrial applications, which in turn, leads to an increased release into the environment, exerting a detrimental impact on plant growth. Thus, it is important to study Sb effects on plants under the current and future CO2 (eCO2). To this end, high Sb concentrations (1500 mg/kg soil) effects under ambient (420 ppm) and eCO2 (710 ppm) on wheat growth, physiology (photosynthesis reactions) and biochemistry (minerals contents, redox state), were studied and soil microbial were evaluated. Our results showed that Sb uptake significantly decreased wheat growth by 42%. This reduction could be explained by the inhibition in photosynthesis rate, Rubisco activity, and photosynthetic pigments (Cha and Chb), by 35%, 44%, and 51%, respectively. Sb significantly reduced total bacterial and fungal count and increased phenolic and organic acids levels in the soil to decrease Sb uptake. Moreover, it induced oxidative markers, as indicated by the increased levels of H2O2 and MDA (1.96 and 2.8-fold compared to the control condition, respectively). To reduce this damage, antioxidant capacity (TAC), CAT, POX, and SOD enzymes activity were increased by 1.61, 2.2, 2.87, and 1.86-fold, respectively. In contrast, eCO2 mitigated growth inhibition in Sb-treated wheat. eCO2 and Sb coapplication mitigated the Sb harmful effect on growth by reducing Sb uptake and improving photosynthesis and Rubisco enzyme activity by 0.58, 1.57, and 1.4-fold compared to the corresponding Sb treatments, respectively. To reduce Sb uptake and improve mineral availability for plants, a high accumulation of phenolics level and organic acids in the soil was observed. eCO2 reduces Sb-induced oxidative damage by improving redox status. In conclusion, our study has provided valuable insights into the physiological and biochemical bases underlie the Sb-stress mitigating of eCO2 conditions. Furthermore, this is important step to define strategies to prevent its adverse effects of Sb on plants in the future.

Targeted curation of the gut microbial gene content modulating human cardiovascular disease.

One of the most-cited examples of the gut microbiome modulating human disease is the microbial metabolism of quaternary amines from protein-rich foods. By-products of this microbial processing promote atherosclerotic heart disease, a leading cause of human mortality globally. Our research addresses current knowledge gaps in our understanding of this microbial metabolism by holistically inventorying the microorganisms and expressed genes catalyzing critical atherosclerosis-promoting and -ameliorating reactions in the human gut. This led to the creation of an open-access resource, the Methylated Amine Gene Inventory of Catabolism database, the first systematic inventory of gut methylated amine metabolism. More importantly, using this resource we deliver here, we show for the first time that these gut microbial genes can predict human disease, paving the way for microbiota-inspired diagnostics and interventions.

Antimicrobial Effects and Antioxidant Activity of Myrtus communis L. Essential Oil in Beef Stored under Different Packaging Conditions.

The aim of this study was to assess the antimicrobial effects of myrtle (Myrtus communis L.) essential oil (EO) on pathogenic (E. coli O157:H7 NCTC 12900; Listeria monocytogenes ATCC BAA-679) and spoilage microbiota in beef and determine its minimum inhibitory concentration (MIC) and antioxidant activity. The behavior of LAB, Enterobacteriaceae, Pseudomonas spp., and fungi, as well as total mesophilic (TM) and total psychotropic (TP) counts, in beef samples, was analyzed during storage at 2 and 8 °C in two different packaging systems (aerobiosis and vacuum). Leaves of myrtle were dried, its EO was extracted by hydrodistillation using a Clevenger-type apparatus, and the chemical composition was determined using chromatographical techniques. The major compounds obtained were myrtenyl acetate (15.5%), β-linalool (12.3%), 1,8-cineole (eucalyptol; 9.9%), geranyl acetate (7.4%), limonene (6.2%), α-pinene (4.4%), linalyl o-aminobenzoate (5.8%), α-terpineol (2.7%), and myrtenol (1.2%). Myrtle EO presented a MIC of 25 µL/mL for E. coli O157:H7 NCTC 12900, E. coli, Listeria monocytogenes ATCC BAA-679, Enterobacteriaceae, and E. coli O157:H7 ATCC 35150 and 50µL/mL for Pseudomonas spp. The samples packed in aerobiosis had higher counts of deteriorative microorganisms than samples packed under vacuum, and samples with myrtle EO presented the lowest microbial contents, indicating good antimicrobial activity in beef samples. Myrtle EO is a viable natural alternative to eliminate or reduce the pathogenic and deteriorative microorganisms of meat, preventing their growth and enhancing meat safety.

Diagnostic performance of metagenomic next-generation sequencing and conventional microbial culture for spinal infection: a retrospective comparative study.

The study evaluated the diagnostic performance of metagenomic next-generation sequencing (mNGS) as a diagnostic test for biopsy samples from patients with suspected spinal infection (SI) and compared the diagnostic performance of mNGS with that of microbial culture. All patients diagnosed with clinical suspicion of SI were enrolled, and data were collected through a retrospective chart review of patient records. Biopsy specimens obtained from each patient were tested via mNGS and microbial culture. Samples were enriched for microbial DNA using the universal DNA extraction kit, whole-genome amplified, and sequenced using MGISEQ-200 instrument. After Low-quality reads removed, the remaining sequences for microbial content were analyzed and aligned using SNAP and kraken2 tools. A total of 39 patients (19 men and 20 women) were deemed suitable for enrollment. The detection rate for pathogens of mNGS was 71.8% (28/39), which was significantly higher than that of microbial culture (23.1%, p = 0.016). Mycobacterium tuberculosis complex was the most frequently isolated. Using pathologic test as the standard reference for SI, thirty-one cases were classified as infected, and eight cases were considered aseptic. The sensitivity and specificity values for detecting pathogens with mNGS were 87.1% and 87.5%, while these rates were 25.8% and 87.5% with conventional culture. mNGS was able to detect 88.9% (8/9) of pathogens identified by conventional culture, with a genus-level sensitivity of 100% (8/8) and a species-level sensitivity of 87.5% (7/8). The present work suggests that mNGS might be superior to microbial culture for detecting SI pathogens.