Total Number Of Bacteria Research Articles

Assessment of Different Sizes Silver Particles According to the Haplic Chernozem Biological Indicators

The ecotoxicity of Ag particles of different sizes was assessed by microbiological, biochemical and phytotoxic indicators of the upper layer (0-20 cm) of ordinary chernozem (Haplic Chernozem) in a laboratory model experiment. We studied the effect of nano- (10 and 100 nm) and microparticles (1000 nm) of Ag at concentrations of 1, 10 and 100 mg/kg on the biological parameters of ordinary chernozem 30 days after contamination: the activity of catalase, dehydrogenases, ferrireductase, urease, peroxidase, poliphenoloxidase, invertase, phosphatase, the total number of bacteria, the abundance of bacteria of the genus Azotobacter, the number of germinated seeds and the length of radish roots. It was found that the ecotoxicity of Ag particles depends on their size: in most cases, Ag particles 10 nm in size had a stronger ecotoxic effect on biological parameters than particles 100 and 1000 nm in size. There were no significant differences in the ecotoxicity of 100 and 1000 nm Ag particles. The difference in the effects of Ag particles of different sizes increased with increasing Ag concentration in the soil: the higher the Ag concentration in the soil (from 1 to 100 mg/kg), the more pronounced the difference in ecotoxicity between 10 nm Ag particles and 100 and 1000 nm Ag particles. Phytotoxic indicators are more sensitive to contamination by Ag nanoparticles at all concentrations studied (1, 10 and 100 mg/ kg); total number of bacteria, invertase and phosphatase activity – at 10 and 100 mg/kg; the abundance of bacteria of the genus Azotobacter and the activity of dehydrogenases – at 100 mg/kg. It is advisable to use these indicators in biodiagnostics of the ecotoxicity of Ag nanoparticles.

Influence of Coated Phycocyanin on Shelf Life of Infected Penaeus semisulcatus

ABSTRACTThe present study was undertaken to evaluate the antioxidant and antimicrobial activity of chitosan‐alginate‐coated phycocyanin (PC) extract from Spirulina sp. on Penaeus semisulcatus infected with Salmonella typhimurium stored at 4°C and 8°C for 21 days. Four groups of shrimp treatments—a control sample (without infection and PC), an infected sample without PC, a non‐infected sample + PC and an infected sample + PC—were used. The toxicity test revealed no toxicity of PC against Caenorhabditis elegans. The results of the pH, thiobarbituric acid, peroxide value (PV) and total volatile basic nitrogen showed that the lowest amounts of these factors were observed in the samples immersed in PC, whereas the highest values belonged to the samples infected with Salmonella. On the basis of the total number of bacteria in food (log 10⁷ CFU/g), the shelf life of shrimps treated with PC increased by 14 and 4 days at 4°C and 8°C, respectively, compared to the control. The diphenyl‐2‐picrylhydrazyl (DPPH) and ABTS results of the antioxidant activity indicated that the highest values were observed in the infected sample + PC after 21 days at 4°C and 8°C (82.65 ± 0.36 and 89.50 ± 0.43), respectively. The results of the colour assessment showed that the highest and lowest values belonged to the control sample (without infection and PC) and the non‐infected sample with PC, respectively. The results of sensory analysis showed that the samples enriched with PC had a higher overall acceptability than samples without PC. In conclusion, PC increased the shelf life of shrimp infected with Salmonella sp.

Schools and Indoor Air Quality: seasonal variation

Abstract Background Indoor Air Quality (IAQ) in schools is a public health concern, given the vulnerability of children as a demographic group and substantial amount of time that they spend in (highly occupied) classrooms. Conditions specific for school buildings, as well as location and outdoor air quality (OAQ), can adversely affect IAQ and children’s health. The aim of this study was to examine the seasonal variation in IAQ and the influence of OAQ herein in primary schools. Methods Sampling was carried out in summer and winter in 5 schools in central Poland. A culture-dependent method using impactors was applied to examine the total number of bacteria and fungi. Gas chromatography with flame ionization detector (quartz filters for sampling) was applied to determine concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), crucial for their health impact. Results In poorly ventilated classrooms bacteria levels exceeded that of fungi. Bacterial contamination decreased in efficiently ventilated rooms, and before/after the lessons. In summer fungi concentration in indoor air was higher than in winter and reached the level of fungi outdoors. PAHs concentrations (especially those with 4 and more rings, which are biologically active) and the mutagenicity and carcinogenicity equivalents were elevated in winter and related to changes in concentrations in outdoor air. Conclusions IAQ in schools depends on a season. Occupants in classrooms are the main source of bacteria, but the type and number of microorganisms also depend on ventilation conditions. PAHs characteristic of coal/wood combustion indicates that in the absence of internal emission sources, external sources most likely affect IAQ in schools in winter.

Evaluation of the Ability of Ameliorants to Influence the Biological Indicators and Hydrophobicity of Oil-Contaminated Haplic Chernozems

ABSTRACT The aim of the study was to assess the ameliorants effect on the biological parameters and Haplic Chernozems hydrophobicity. In model experiment conditions, Haplic Chernozem was polluted by oil and remediation with application of nitroammophos, Sodium humate, biochar, and Baikal EM-1 was simulated during to 30, 90, and 180 days. Indicators of soils activity – germination and intensity indicators of initial seed growth, the activity of catalase and dehydrogenases, the total number of bacteria, hydrophobicity were studied. On the 30 and 90th days after remediation, the most significant reliable decrease in oil regarding was promoted by 2 D biochar. After 180 days of dose 1 D and dose 2 D nitroammophos, as well as 1 D Baikal EM-1, the total petroleum hydrocarbon content was reduced significantly. Baikal EM-1 and biochar contributes to the greatest decrease in hydrophobicity at all periods of the experiment to a greater extent. On the 30th day, the introduction of nitroammophos, biochar, and 1 D Sodium humate contributed to an increase in the integral indicator of the biological state of oil-contaminated Haplic Chernozem, on the 90th day, the introduction of all doses of biochar led to an increase in the indicator, and on the 180th – all doses of Baikal EM-1, and 0.5 D Sodium humate. The research results may be used when choosing a method of soil restoration after oil pollution.

Microbiomes-Plant Interactions and K-Humate Application for Salinity Stress Mitigation and Yield Enhancement in Wheat and Faba Bean in Egypt’s Northeastern Delta

Salinity, resulting from climate change and excessive mineral fertilization, burdens farmers and negatively impacts soil and water ecosystems in the Northeastern Nile Delta. Organic and biological approaches are crucial for addressing these issues. This study examined the effects of individual and combined inoculations with cyanobacteria, yeast, and Arbuscular Mycorrhizal Fungi (AMF), with or without K-Humate and reducing Nitrogen, phosphorus and potassium (NPK) mineral fertilizers application rates to crop quality of wheat and faba bean. In preliminary laboratory experiments, the interactive effects of these microbiomes on plant antioxidant and soil enzyme production were examined under salinity stress. Results showed that co-inoculation, especially with K-Humate, yielded superior outcomes compared to individual inoculations. These findings were validated by a field trial conducted in saline-alkaline soil in the Northeastern Nile Delta region. All biological treatments 25% of recommended doses, and enhancing salinity tolerance, increasing yield, and improving enhanced rhizosphere microbial activity, including soil enzyme activity, AMF colonization, spore density, and the total numbers of bacteria, cyanobacteria, and yeast. These effects were further amplified by K-Humate and were more pronounced with combined inoculations than with individual ones, leading to improved soil fertility and significant increases in both crop quantity and quality compared to control treatments. The triple treatment, combining cyanobacteria, yeast, and mycorrhizae in the presence of K-Humate while reducing the mineral NPK rate by 75%, achieved superior increases in the productivity of wheat grains and faba bean seeds, reaching 54.72% and 128.92%, respectively, compared to the 100% NPK mineral control. This treatment also significantly improved crop quality, with notable increases in nitrogen, potassium, phosphorus, and protein percentages in wheat grains and faba bean seeds. Microbiomes-interaction increased potassium uptake over sodium, enhancing the plant’s potassium/sodium ratio and improving salt stress tolerance. This approach reduces reliance on costly mineral fertilizers, enabling bio-organic farming in marginal lands, optimizing resource utilization, and preserving natural resources.

Long lasting degradation of all alkanes in soil by Pseudomonas activated after Fenton pre-oxidation

This study investigated the function and mechanism of Fenton pre-oxidation on the long lasting degradation of all alkanes in soil contaminated by petroleum. The findings demonstrated that the biological removal amount of all alkanes in the respiratory regulation group reached 4083.46 mg/kg, which was twice that of the non-regulation group, and the removal amount gradually increased in the four stages of bioremediation. In addition, the removal amount of all alkanes in the non-regulated group did not change much and showed a downward trend, indicating that long lasting degradation of all alkanes could be achieved by the respiratory regulation group, and the biodegradation cycle was saved by 251 days compared with the non-regulated group. Furthermore, the total number of bacteria in the respiratory regulation group (6.73 log CFU/g) was significantly higher than that in the non-regulation group (2.25 log CFU/g). Pseudomonas became the dominant genus in the respiratory regulation group with an average relative abundance of 32.17 %. In the respiratory regulation group, a large amount of ammonia nitrogen (1703.62 mg/kg) was consumed during the degradation process, which stimulated the tricarboxylic acid cycle respiratory metabolism process of Pseudomonas and accelerated the hydrocarbon conversion. This may be the reason why the long lasting degradation of all alkanes in soil could be achieved by the respiratory regulation group.

Investigation of the structure and chemical composition of sediments of irrigators of the tower cooling tower

RELEVANCE. The relevance of this study lies in the need to preserve their design cooling efficiency during the operation of cooling towers, as well as to prevent a decrease in the mechanical strength of sprinklers as a result of the formation of deposits that contribute to the deterioration of heat exchange conditions and strength characteristics of structural elements.OBJECT. Increasing the efficiency of heat transfer in the cooling processes of circulating water when using tower cooling towers at thermal power plants.METHODS. To achieve these goals, comprehensive studies of samples of circulating water and sediments formed on the sprinklers of tower cooling towers were carried out using classical methods of physico-chemical and elemental analyses, as well as sediment studies using X-ray diffraction analysis and electron microscopy.RESULTS. The relationship between the parameters of cooling water and the nature of sedimentsformed on the sprinklers, in particular the proportion of crystalline and non-organic ones, has been tracked. A method of highly effective pretreatment of source water with biodegradable biocidal reagents was considered in detail, since the existing disinfection method does not prevent the development of colonies of microorganisms on cooling tower sprinklers. The effectiveness of the use of the biodegradable THPS reagent, which is relatively safe for the environment in comparison with oxidizing biocides and classic bromine-based preparations, was studied in laboratory conditions. Laboratory studies were conducted in accordance with the interstate standard and included the determination of the total number of microorganisms and common colimorphic bacteria. Studies have shown that THPS treatment allows for the complete presence of microorganisms in cooling water samples. Biocidal treatment was carried out with reduced concentrations of the reagent (up to 30 mg/l) in a wide pH range (from 6.5 to 9.0 units). Experiments have shown high efficacy of the drug in a wide pH range even when it is dosed in small doses and a decrease in the effectiveness of this biocide when using increased concentrations of cationic flocculants used at the stage of pretreatment of river water.

Characterization Studies on the sugC Gene of Streptococcus suis Serotype 2 in Adhesion, Invasion, and Virulence in Mice.

The sugC gene of Streptococcus suis (S. suis) is a coding gene for the ATP-binding transporter-associated protein with strong pathogenicity. In order to reveal the effect of the sugC gene on the virulence of S. suis serotype 2, a wild-type strain of TJS75, isolated from fattening pigs' brain tissue samples, was used as a parent strain, and a knockout sugC gene (ΔsugC) and complementary strain (CΔsugC) were successfully constructed via homologous recombination technology. The biological characteristics of TJS75, ΔsugC and CΔsugC were compared and analyzed through growth curves, biochemical characteristics, hemolysis characteristics, cell infection tests and pathogenicity tests on BALB/c mice. The results of the growth characteristic experiments in vitro showed that the plateau stage growth period of ΔsugC was delayed compared to the TJS75 strain, but there was no difference in the total number of bacteria. The biochemical characteristics and hemolysis ability of ΔsugC in sheep blood had no difference compared with TJS75, but its adhesion and invasion abilities in PK-15 cells were decreased. Knockout of the sugC gene had no impact on the expression levels of adhesion-related genes in TJS75 in real-time PCR analysis. In addition, the LD50 of ΔsugC in BALB/c mice was 1.47 × 108 CFU, seven times higher than that of TJS75 (LD50 = 2.15 × 107 CFU). These results illustrate that the deletion of sugC reduced the virulence of TJS75 to BALB/c mice, but its role in the adhesion and invasion of PK-15 cells in this strain needs to be further explored. In summary, this study provides evidence that the sugC gene is a virulence-related gene in the S. suis serotype 2 strain and plays a crucial role in the adhesion and invasion of S. suis. This study lays a foundation for the further exploration of the potential virulence factors and pathogenesis of S. suis.

Study the effect of lactoperoxidase activation in combination with heat treatment or nisin on the microbiological quality of raw milk

The aim of the current study was to improve the microbiological quality of raw cow milk by activating the lactoperoxidase system using either nisin or heat treatment. A central composite experimental design with three factors was used to evaluate the effect of thiocyanate (SCN), hydrogen peroxide (H202) and nisin on the microbiological quality of raw milk. The experimental response was measured in terms of the logarithmic reduction in total microbial, total coliforms count, yeasts and molds. Our results indicate that the combination of both treatments was highly effective in destroying various microorganisms. In fact, the optimal values of each parameter (SCN, H202 and nisin) for a 6log, 5log and 4log reductions of the initial number of total aerobic mesophilic bacteria, coliforms, yeasts and molds were around 7 mg/L of SCN, 15 mg/L of H202 and 50 IU/mL of nisin, obtained after 72 h of incubation at 25 °C. Concerning the LPS activation at moderate temperature, our data suggest that this combination was very effective in destroying different microorganisms. Certainly, the total destruction of coliforms, yeasts and molds was noted after 96 h incubation at 25 °C after LPS activation for 4 h and 6 h followed by heat treatment (63 °C for 30 min). These results highlight a synergistic effect between the LPS activation and nisin or heat treatment in preserving microbiological quality of raw milk for 72 h or 96 h at 25 °C, respectively. Such treatments could be implemented by the dairy industry to enhance the quality of fresh milk and consequently of dairy products.

Microbiological Quality of Sheep's Milk from The Area of Vlasic - Travnik as An Ingredient of Travnik Cheese

The aim of the research is to assess the microbiological correctness and quality of sheep's milk, which is primarily used as a raw material for the production of Travnik - Vlasic cheese, and originates from the Vlasic - Travnik area, with an emphasis on assessing its compliance with the requirements of the current legislation for raw milk. In general, Travnik - Vlasic cheese is produced, according to the original technology, from unpasteurized milk, and therefore the purity of the raw material is extremely important. The samples were collected during the first months of lactation, March and April 2023, from 8 primary producers from the Vlasic - Travnik area, and were analyzed for the total number of bacteria and all samples meet the criteria of the regulations.

Honeydew Honey as a Reservoir of Bacteria with Antibacterial and Probiotic Properties.

The purpose of this study was to isolate, identify, and evaluate the antibacterial and probiotic potential of bacteria from honeydew honey collected in Poland. Isolates (189 colonies from 10 honey samples) were evaluated for their antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Yersinia enterocolitica, and then identified by MALDI-TOF-MS. The isolates with the greatest antimicrobial properties were screened for their probiotic potential. The total number of bacteria isolated from honey did not exceed the value of 2.5 × 102 CFU/mL. The Bacillus pumilus/altitudinis, B. licheniformis, and Bacillus cereus groups were the dominant identified bacteria. Almost 16% of the isolates expressed antibacterial potential against three pathogenic bacteria, over 20% against two, while almost 34% of the isolates did not inhibit any. The survival rate of the isolates under gastrointestinal tract conditions was higher after 4 h of exposure to bile salts (>60% survival rate for 66.66% of the isolates), while at pH 2.0, it was lower (>50% survival rate for 44% of the isolates). The most resistant isolate B. pumilus/altitudinis survived at a rate of 77% at low pH and 108% with bile salts. These results confirmed that honeydew honey is a promising reservoir of bacteria that produces metabolites with antimicrobial and probiotic potential.

Investigation of microbiological quality of indoor air in university campus due to students returning after COVID-19 restriction

Abstract COVID-19 has opened the world’s eyes to microbiological indoor air quality, which is essential to know the disease’s behaviour and spread. COVID-19 has caused several campuses to restrict campus activities to minimize the virus’s transmission among students. As students return to campus, microbiological indoor air quality can deteriorate. Therefore, understanding related to this matter needs to be improved. This study aims to give a glimpse to investigate the impact of a student returning to microbiological indoor air quality and determine the main contributing factors influencing it. This study measured two microbial air pollutants, total bacteria, and fungi, in a different indoor environment at the Sumatra Institute of Technology in Lampung, Indonesia. Simultaneously, the main factor, (the number of occupants/students) and several environmental factors that could potentially influence microbial air pollutants such as room temperature, relative humidity, light intensity, ventilation area, and the direction of wind movement were also measured. Compared to measurements taken during the pandemic, the intensified number of averaged total bacteria and total fungi reached 248% and 63%, respectively. The total bacteria measured at the sampling locations were higher than the total fungi of 799.27 CFU/m3 compared to 552.99 CFU/m3. The number of bacteria also exceeds the Indonesian Bacteria Indoor Air Quality parameters standard. Based on the regression linier analysis, different significant variables influence each parameter. In general, the return of students after COVID-19 restrictions has significantly affected indoor microbiological air quality. In addition, the environmental factors that affect the parameters of bacteria and fungi are different, so further attention shall be addressed by the campus.

Bactericidal effect of ultrasound on glutinous rice during soaking and its influence on physicochemical properties of starch and quality characteristics of sweet dumplings

The soaking process of glutinous rice allows the growth and reproduction of microorganisms, which can easily cause food safety problems. In this work, the effects of different ultrasonic powers (150 W, 300 W, 450 W, and 600 W) on the bactericidal effect of glutinous rice, the physicochemical properties of starch and the quality characteristics of sweet dumplings were studied. Compared with soaking for 0 and 2 h, sonication of glutinous rice after soaking for 4 h was more effective at reducing the number of microorganisms in soaked glutinous rice, and the bactericidal effect increased with increasing ultrasound intensity. After 30 min, the total number of bacteria decreased by 2.04 log CFU/g. Moreover, ultrasonic treatment destroys the grain structure of glutinous rice starch, resulting in the formation of dents and cracks on the starch surface, increasing the amylose content, improving its expansion, reducing its short-range order and relative crystallinity, and altering its gelatinization characteristics. In addition, ultrasonic treatment increased the soup transparency of sweet dumplings from 51.8 % to 63.95 %, reducing their hardness, chewiness and adhesiveness. In summary, ultrasonic treatment can not only effectively kill microorganisms in soaked glutinous rice but also improve the quality of glutinous rice dumplings by changing the physicochemical properties of glutinous rice starch. The results of this study provide theoretical support for the application of ultrasonic technology in glutinous rice food production.

Regulation of Antibiotic Resistance Genes on Agricultural Land Is Dependent on Both Choice of Organic Amendment and Prevalence of Predatory Bacteria.

Antibiotic resistance genes (ARGs) are widespread in the environment, and soils, specifically, are hotspots for microorganisms with inherent antibiotic resistance. Manure and sludge used as fertilizers in agricultural production have been shown to contain vast amounts of ARGs, and due to continued applications, ARGs accumulate in agricultural soils. Some soils, however, harbor a resilience capacity that could depend on specific soil properties, as well as the presence of predatory bacteria that are able to hydrolyse living bacteria, including bacteria of clinical importance. The objectives of this study were to (i) investigate if the antibiotic resistance profile of the soil microbiota could be differently affected by the addition of cow manure, chicken manure, and sludge, and (ii) investigate if the amendments had an effect on the presence of predatory bacteria. The three organic amendments were mixed separately with a field soil, divided into pots, and incubated in a greenhouse for 28 days. Droplet digital PCR (ddPCR) was used to quantify three ARGs, two predatory bacteria, and total number of bacteria. In this study, we demonstrated that the choice of organic amendment significantly affected the antibiotic resistance profile of soil, and promoted the growth of predatory bacteria, while the total number of bacteria was unaffected.

Effects of Dioscorea opposita mucilage addition on the physicochemical properties, texture, and stability of set-type yogurt

Dioscorea opposita mucilage (DOM), a polysaccharide-protein polymer with antioxidant activity, can be served as a natural ingredient in nutritional yogurts. The effects of DOM addition at different concentrations (2%, 4%, 6%, 8%, 10% and 12% w/w) on the total number of lactic acid bacteria, pH, titratable acidity, syneresis, viscosity, texture, color and sensory evaluations of full-fat yogurts and skimmed yogurts during 21 days storage at 4 °C were investigated. The results suggested that DOM could improve the growth of LAB, strengthen the network and gelation of yogurt, and thicken the dispersion, which led to the significant decrease in pH and cohesiveness, and drastic increase in the syneresis, firmness and adhesiveness. Additionally, sensory evaluation revealed that the overall liking scores of full-fat yogurts (8.1–8.7) were higher than those of skimmed yogurts (7.9–8.3), which exhibited strong correlations with firmness and viscosity of set-type yogurts. Although DOM addition affected the sensory undesirably, such as creaminess, the thickness and overall liking were improved, especially for the skimmed yogurts. In summary, 8% w/w DOM could effectively improve the texture, quality and stability of set-type yogurts. This study provides new applications in functional dairy products and promotes the value of the by-products of D. opposita.

The Effect Of Casgot Property On The Biological Properties Of Soil In Which Cucumbers Are Planted

Soil biological properties are various aspects related to the life of microorganisms and macroorganisms in the soil and biological activities. This study aims to understand how soil organisms and their biological activities contribute to soil fertility and plant health. This study used a purposive sampling method and was analyzed using descriptive analysis. Soil biological properties, including the total number of bacteria and fungi, were observed to assess the effect of Black Soldier Fly larvae (kasgot) fertilizer application. The results showed that treatment variations had a significant effect on the population of fungi and bacteria in the rhizosphere. The highest value of the fungal population was recorded in the M1 treatment without the first treatment, while the lowest value was in the M1 treatment with the first treatment, indicating that the type and frequency of treatment can drastically affect fungal growth. For the bacterial population, the M3 treatment in the first application showed the highest effectiveness, while the M2 treatment in the second application showed the lowest results, highlighting the importance of the dose and application stage in increasing the bacterial population. Overall, this study emphasizes the importance of selecting the right treatment to optimize the soil microbial population in agricultural practices.

Possibility of Concentrating Milk Enriched with Lemongrass (Cymbopogon) as a Preservative using Ultrafiltration Technology

Background: This study aimed at the possibility of concentrating milk in the laboratory using ultra-filtration technology instead of the traditional evaporation method that is still used in Iraq. Methods: Therefore, 5 litres of raw, cow milk were taken from a reliable source and two different concentrations of lemongrass were added as a preservative to observe the changes occurring during concentration, chemically and microbial. The best conditions were found to concentrate the milk 2.7 once and improve it over many days with the addition of lemongrass extract as a preservative. A material with a flat membrane polyethyle-solphen with a measurement of 10 kdalton (Snyder USA) was selected. Throughout the duration of the more than three-hour experiment, the measurements were taken. Two sets of data were examined: in the first set, the flow rate was varied between 0.15 and 0.25 L/min while the trans membrane pressure (TMP) was kept constant at 2 bar. The value of 0.15 L/min was determined to be the ideal flux. In the second group, the trans membrane pressure was varied between 0.5 and 1,2 bar while the flow rate was kept constant at 0.15 L/min. At TMP 2 bar, the ideal flux value was discovered at 35°C, the permeate flux was around 5-7 L/m2.hr. Result: It was found the change of the total solid and protein were excellent percentages with time of filtration. The total number of bacteria at both concentrations decreased significantly (p less than 0.05) in the biological test results.

Nano-Bioremediation of Arsenic and Its Effect on the Biological Activity and Growth of Maize Plants Grown in Highly Arsenic-Contaminated Soil.

Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg-1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants.

Rhizosphere Bacteria Help to Compensate for Pesticide-Induced Stress in Plants.

Although exogenous chemicals frequently exhibit a biphasic response in regulating plant growth, characterized by low-dose stimulation and high-dose inhibition, the underlying mechanisms remain elusive. This study demonstrates, for the first time, the compensatory function of rhizosphere microbiota in assisting plants to withstand pesticide stress. It was observed that pak choi plants, in response to foliar-spraying imidacloprid at both low and high doses, could increase the total number of rhizosphere bacteria and enrich numerous beneficial bacteria. These bacteria have capabilities for promoting plant growth and degrading the pesticide, such as Nocardioides, Brevundimonas, and Sphingomonas. The beneficial bacterial communities were recruited by stressed plants through increasing the release of primary metabolites in root exudates, such as amino acids, fatty acids, and lysophosphatidylcholines. At low doses of pesticide application, the microbial compensatory effect overcame pesticide stress, leading to plant growth promotion. However, with high doses of pesticide application, the microbial compensatory effect was insufficient to counteract pesticide stress, resulting in plant growth inhibition. These findings pave the way for designing improved pesticide application strategies and contribute to a better understanding of how rhizosphere microbiota can be used as an eco-friendly approach to mitigate chemical-induced stress in crops.

Quality of cow’s milk as a raw material in the dairy industry from the Pelagonian region in North Macedonia

This scientific work provides a comparison and analysis of the quality and hygiene requirements of raw cow’s milk obtained from individual producers of large and small farms in three regions of Pelagonia in accordance with the Rulebook on requirements for quality, safety and hygiene of milk. The examinations include analysis of the parameters of the chemical composition, determination of the number of somatic cells and total number of bacteria from milk samples taken throughout the year from small and large farms. The best results (p<0.05) for the protein content are observed in the milk coming from small and large farms from the Southern part of the Pelagonia region, compared to the Northern part of the Pelagonia region and Prilep region. The amount of dry fat-free matter in the milk from small farms in all three regions did not show a statistically significant difference (p<0.05). The results for the lactose content of milk from all three examined regions are within the limits of the Rulebook for raw milk. A significant difference (p<0.01) was found for the content of somatic cells in small farms. It is noteworthy that small farms deviate significantly from the safety and hygiene requirements outlined in the Rulebook, primarily due to the hygiene practices concerning dairy cows. The results obtained will be valuable for the dairy industry, as they will identify weaknesses among domestic producers. Professional services will implement measures and activities to help farmers meet EU standards in milk production. Additionally, these findings will provide a significant basis for establishing strategies in this agricultural sector.