Populations Of Bacteria Research Articles

Populasi Bakteri Penambat N2 Atmosfer pada Tanah Sawah yang Diberikan Herbisida dengan Berbagai Kandungan Bahan Aktif

Supporting the increase in agricultural production today cannot be separated from the use of herbicides in land preparation activities. Most of the herbicides applied to plants will eventually fall to the ground, then undergo changes and in a certain time will be absorbed by the clay fraction and organic matter in the soil, which is generally known as herbicide residue. Toxic herbicide residues in the soil can kill soil microbes, which are not actually the target (non-target microorganisms) so that they interfere with the activity of soil microorganisms which in turn can affect the nutrient cycle in the soil.This research was conducted with the aim of knowing the effect of giving herbicides with various types of active ingredients in paddy fields on the viability of N-fixing bacteria and their relationship to soil chemical properties.The research and analysis was carried out from November 2021 to January 2022. The method used in this study was the Completely Randomized Design (CRD) environmental design method with a single factor treatment design, namely the type of herbicide active ingredient. Based on the results of research that has been carried out, it is known that the herbicide Glyphosate can increase the population of atmospheric N2-fixing bacteria in the soil, while the herbicide Paraquat and Methyl Metsulfuron can suppress the population growth of atmospheric N2-fixing bacteria

Sourdough starter culture microbiomes influence physical and chemical properties of wheat bread.

Sourdough fermentation is an ancient leavening method that uses wild yeasts to produce carbon dioxide, contributing to bread rise, and bacteria which produce organic acids. Sourdough starter cultures are known to be diverse in terms of the microorganisms they comprise and while specific genera and species of microorganisms have been identified from starters and associated with specific attributes, overarching relationships between sourdough starter culture microbiomes and bread quality are not well understood. The objective of this study was to characterize differences in the physical and chemical properties of breads produced with sourdough starter cultures with unique microbiomes. Sourdough starter cultures (n=20) of known microbial populations were used to produce wheat-based dough and bread, which were analyzed for chemical and physical properties then compared to their microbial populations in order to identify relationships between microbial profiles and dough/bread qualities. All samples were also compared to bread produced only with Saccharomyces cerevisiae (baker's yeast). Significant differences among pH, titratable acidity, loaf volume, crumb firmness, crust color, free amino acids, and organic acids were observed when comparing sourdough breads to the yeast-only control (p≤0.05). Furthermore, bacterial diversity of sourdough starter cultures was correlated with lactic acid and free amino acid in the dough and loaf volume and crumb firmness of baked breads. No significant correlations were found between fungal diversity and measured outcomes. These data demonstrate the importance of considering sourdough starter microbiomes as an ingredient in baked goods and they contribute to quality and safety outcomes in bread production. PRACTICAL APPLICATION: Sourdough starter cultures have diverse and dynamic populations of bacteria and yeasts, which contribute to the production of bread products. These populations can influence the physical and chemical properties of sourdough fermentation and final breads. Understanding of the relationship between sourdough starter microbiomes and bread quality parameters can lead to targeted development of sourdough bread products with specific physical and chemical properties.

Multiple Functions of Microbes to Improve Food and Soil Nutrition in Support of Environment Management to Maintain Global Agricultural Practices

Plant-microbe interactions are interesting phenomena Soil microbial biomass is considered the living part of the soil organic matter, which acts as an agent of transformation of organic matter and is a source of available nutrients. Activities of soil microbes can change the soil environment rapidly and influence the rate of nutrient cycling. Soil microbes also play a significant role in the formation of macro aggregates. The potential of soil microorganisms has been recognized widely for the improvement of soil quality, soil formation, aggregation, and revegetation. Soil microbes are involved in various ecosystem processes, such as litter decomposition, phosphate solubilization, nitrogen fixation, oxidation of various inorganic components of soil or mineralization of inorganic components, and mycorrhizal symbiosis. Implications of plants and their symbionts like mycorrhizal fungi, nitrogen-fixing bacteria, and free-living rhizosphere populations of bacteria promote plant establishment and growth. Therefore, active soil microbial biomass is an essential component for long-term soil fertility. The application of microbial technology which we can refer to as green technology has become an integral element of forestry as well as agriculture and has substantially contributed to forest and agricultural productivity and ensuring the ecosystem’s sustainability. This article reviews some of the important aspects of microbial applications in agriculture and forestry and discusses different facets of microbial functions, their interaction with plants and soil, and their role in the sustainability of natural resources, forests, and agroecosystems.

Benefits of isochoric freezing for carrot juice preservation.

Isochoric freezing (IF) at -5°C/77 and -10°C/100MPa was used to preserve carrot juice for 12 weeks. The juice qualities were compared to those using heat treatment (HT) at 95°C for 15s followed by cold storage at 4°C. The native population of total aerobic bacteria, yeasts, and molds in isochoric frozen juice remained below the detection limit for 12 weeks. In comparison, microbes started to grow in heat-treated juices after 3 weeks of refrigeration. The color of isochoric frozen juice appeared more deep orange than the fresh juice due to an increase in carotenoid extractability. IF was not effective in reducing the activities of peroxidase, polyphenol oxidase, and pectin methyl esterase compared with HT. However, the isochoric samples showed higher carotenoid content, polyphenol content, and antioxidant capacity compared to the fresh and heat-treated juices. PRACTICAL APPLICATION: Isochoric freezing was used to produce carrot juice with extended shelf life. Isochoric freezing could be a beneficial alternative to conventional heat treatment for carrot juice processing as the applied pressures reached total inactivation levels of spoilage microorganisms. Moreover, the low processing temperatures better retained desirable compounds and quality attributes of fresh juice throughout its shelf life.

Polyamide Electrospun Nanofibers Functionalized with Silica and Titanium Dioxide Nanoparticles for Efficient Dye Removal

In this work, novel multifunctional electrospun nanofibrous membranes made of polyamide (PA6) and loaded with silica (SiO2) and/or titanium dioxide (TiO2) nanoparticles were fabricated. SiO2 NPs were first prepared and then characterized by TEM, FE-SEM, and FTIR, and by using XRD techniques, confirming the formation of cristobalite tetragonal crystals with high purity. Different nanofibrous mats, loaded with SiO2 NPs, TiO2 NPs, or both SiO2 and TiO2 NPs, were investigated. Morphological studies indicated that SiO2 and TiO2 nanoparticles tend to be arranged along the fiber surface, also promoting the formation of anatase nanorods when they are mixed into the nanofibers. In this last scenario, mechanical tests have demonstrated that the presence of SiO2 contributed to balancing the mechanical response of fibers that are negatively affected by the presence of TiO2 NPs—as confirmed by tensile tests. More interestingly, the presence of SiO2 did not negatively affect the antibacterial response against different bacteria populations (i.e., Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Bacillus subtilis, and Candida albicans), which is mainly ascribable to the presence of TiO2 particles. Accordingly, the TiO2- and TiO2/SiO2-loaded fibers showed higher methylene blue (MB) absorption values—i.e., 26 mg/g and 27 mg/g—respectively, compared to the SiO2-loaded fibers (23 mg/g), with kinetics in good agreement with the second-order kinetic model. The obtained findings pave the way for the formation of novel antibacterial membranes with a promising use in water purification.

Regulation of Gut Microbiota by Herbal Medicines.

Preserving host health and homeostasis is largely dependent on the human gut microbiome, a varied and ever-changing population of bacteria living in the gastrointestinal tract. This article aims to explore the multifaceted functions of the gut microbiome and shed light on the evolving field of research investigating the impact of herbal medicines on both the composition and functionality of the gut microbiome. Through a comprehensive overview, we aim to provide insights into the intricate relationship between herbal remedies and the gut microbiome, fostering a better understanding of their potential implications for human health.The gut microbiota is composed of trillions of microorganisms, predominantly bacteria, but also viruses, fungi, and archaea. It functions as a complex ecosystem that interacts with the host in various ways. It aids in nutrient metabolism, modulates the immune system, provides protection against pathogens, and influences host physiology. Moreover, it has been linked to a range of health outcomes, including digestion, metabolic health, and even mental well-being. Recent research has shed light on the potential of herbal medicines to modulate the gut microbiome. Herbal medicines, derived from plants and often used in traditional medicine systems, contain a diverse array of phytochemicals, which can directly or indirectly impact gut microbial composition. These phytochemicals can either act as prebiotics, promoting the growth of beneficial bacteria, or possess antimicrobial properties, targeting harmful pathogens. Several studies have demonstrated the effects of specific herbal medicines on the gut microbiome. For example, extracts from herbs have been shown to enhance the abundance of beneficial bacteria, such as Bifidobacterium and Lactobacillus, while reducing potentially harmful microbes. Moreover, herbal medicines have exhibited promising antimicrobial effects against certain pathogenic bacteria. The modulation of the gut microbiome by herbal medicines has potential therapeutic implications. Research suggests herbal interventions could be harnessed to alleviate gastrointestinal disorders, support immune function, and even impact metabolic health. However, it is important to note that individual responses to herbal treatments can vary due to genetics, diet, and baseline microbiome composition. In conclusion, the gut microbiome is a critical player in maintaining human health, and its modulation by herbal medicines is a burgeoning area of research. Understanding the complex interactions between herbal compounds and gut microbiota will pave the way for innovative approaches to personalized healthcare and the development of herbal-based therapeutics aimed at promoting gut health and overall well-being.

Dynamics of microbial populations in the composting process of marine organic waste

It is estimated that marine waste consist of 60% organic material. Therefore, waste must be handled using a composting process. The main determining factor in the composting process is the microorganisms associated with the C/N ratio. Therefore, this research was conducted to observe the dynamics of microbial populations during the decomposition of marine organic waste. The research method for calculating microbial populations (bacteria and fungi) is the dilution method using a colony counter with the Pour Platedilution technique (CFU/g). The results showed that the microbial population, both fungi and bacteria, fluctuated from week 1 to 10 of the composting process. This is related to the temperature during the composting process and the C/N ratio. The highest population of bacteria and fungi was found in the sixth week of composting at 300 x 107 CFU/g where the process entered the thermophilic phase with a C/N of 55.

Tripartite Introductions of PGPR, Humic Acid, and N-Fertilizer Improve the Growth and Yield of Sweet Potato Under Glasshouse Conditions

This study was undertaken to investigate the effects of plant growth-promoting rhizobacteria (PGPR) with humic acid (HA) as amendments on the morphological and physiological growth characteristics and yield of Sepang Oren sweet potato (Ipomoea batatas[L.] Lam). The experiment was conducted under glasshouse conditions at the Faculty of Agriculture, Universiti Putra Malaysia, for 110 days. Two factors were used in this experiment: The first factor was PGPR-HA inoculations (UPMB10, UPMRB9, and mixed strains) and non-inoculation-HA, and the second factor was the Nitrogen fertilizer levels (50, 75, and 100%). The treatments were replicated three times and arranged factorially in a randomized complete block design. The results showed that inoculations with PGPRs-HA (UPMRB9 and UPMB10 strains) positively affect the plant growth significantly (SPAD measurements, number of leaves, vine length, root length, leaf area index, root dry weight, shoot dry weight, and root: shoot ratio) of sweet potato upon addition of 50% and 75% of N-fertilizer, respectively. The nutrient content of soil and plant leaf significantly increased by 12-15% and 14-18%, respectively, compared to the uninoculated, when applied with the same inoculation. After 30 days, the population of soil bacteria increased, reaching a value of 8.65 log10 CFU/g soil. The use of PGPR-HA inoculations with N-fertilization resulted in a considerable rise in the majority of plant and soil parameters compared to the treatments without PGPR inoculation. Therefore, PGPR supplemented with humic acid (HA) may be considered a viable and sustainable strategy for enhancing sweet potatoes' morphological and physiological attributes. This technique can result in increased crop productivity and serve as a substitute for nitrogen-based fertilizers.

Lactic acid bacteria administration from Jember tempeh (Indonesia) as a probiotic candidate in intestinal physiology and histology of mice strain Balb-C

Abstract. Azizah SN, Rosida, Hidayah AN, Dwijayanti AR. 2023. Lactic acid bacteria administration from Jember tempeh (Indonesia) as a probiotic candidate in intestinal physiology and histology of mice strain Balb-C. Biodiversitas 24: 6969-6978. The lactic acid bacteria of tempeh have been studied for their potential as a probiotic with highly beneficial effects on health. This study aimed to investigate the potential of lactic acid bacteria from Jember tempeh on white mice's intestinal physiology and histology. The highest population of lactic acid bacteria isolated from three Jember tempeh types with GYP solid media was found in the Kaliwates tempeh (TK) at 2.74 × 108 cells/ml. According to the purification and lactic acid activity, the LAB isolates, encoded as TA.1, TB.1, TK.1, TK.2, and TK.4 are all probiotic candidates. All isolates obtained the optimum growth time at the 15th hour in TA.1 and TB.1 isolates, the 6th hour in TK.1 and TK.2 isolates, and the 8th hour in TK.4 isolate. The administration of LAB probiotics from Jember tempeh on the weight gain of mice presents a sig value of 0.38>0.05, which means an insignificant effect on the weight gain among the group. The solid feces condition of mice was also similar within groups. The administration of LAB probiotics on the intestinal histology of mice presents a sig value of 0.028<0.05, which means a significant effect within groups, showing a similar condition between the consortium administration group and the normal group. Groups TA.1, TB.1, TK.1, TK.4 and control (Lactobacillus acidophillus) had the same intestinal histology, namely partial necrosis. The administration of LAB probiotics from Jember tempeh can also reduce the population of Salmonella and Escherichia coli bacteria more effectively than without the probiotics. Thus, a good treatment group used as a probiotic candidate is a consortium.

Solid state fermentation characteristic of rice straw using herbivore s cecum microbes

This study was aimed at identifying highly capable lignolytic microbes from nature for use in Solid State Fermentation (SSF) of rice straw. The SSF silage was prepared in laboratory scale, as the following treatments: uninoculated (control), Lactobacillus plantarum FCC 123 (LP), fiber-degrading fungi (Aspergillus sp.) from horse cecum (FF), and fiber-degrading bacteria (Enterococcus casseliflavus) from buffalo cecum (FB). Incubation was carried out for a month at room temperature. The observed parameters were: organic acids, water-soluble carbohydrate (WSC), microorganism and nutrient composition. Rice straw SSF that was inoculated with LP showed the highest quality of fermentation, indicated by significant highest lactic acid bacteria (LAB) population, and has the lowest of poor bacteria indicators (coliform, aerobic bacteria, and bacilli). The LP treatment also has the highest LAB content and lowest WSC. Among treatments, FB treatment seems to have given a similar result with LP followed by FF. While the chemical composition seems unaffected by treatments. Compared with the fresh material, all fermentation with and without inoculants has reduced neutral detergent fiber (NDF) and increased acid detergent fiber (ADF), but there were no differences among all treatments. Inoculation of both LP and FB could improve rice straw SSF silage quality, but this system could not improve fiber degradation as well as in liquid state fermentation (LSF). Keywords: Microorganism, Organic acid, Silage, Straw, Water soluble carbohydrate

The principal component analysis of key and significant features of the safety and nutritional value of Mahyaveh sauce.

The objective of present research is to evaluate the changes in the chemical, microbial, and biogenic amines in Persian fish sauce (Mahyaveh) during 40 days of fermentation. In the current survey, the parameters of salt percentage, pH, total nitrogen concentration, amino nitrogen concentration, Brix, color features, cadaverine, and histamine concentration were measured in the fish sauce. The amino nitrogen content, total protein, Brix, and salt were increased along with the progression of fermentation process. The microbial population of Mahyaveh sauce demonstrated that lactic acid bacteria (LAB), total bacterial count, and Enterobacteriaceae decreased during fermentation. The population of lactic acid bacteria and the total count of bacteria were around one logarithmic cycle lower in the presence of 10% salt than under low salt conditions. Histamine and cadaverine concentrations increased to 43.49 and 42.76 mg/kg during the fermentation period, respectively. As a result, the population density of histamine-producing bacteria rose from 3.00 log CFU/mL at the beginning to 4.58 log CFU/mL at the end of process. The population density of cadaverine-producing bacteria was 3.43 and 5.24 log CFU/mL on the 20th and 40th days of fermentation, respectively. Sensory evaluation results indicated that our sample of fish sauce had an overall acceptability score of 5.1 (good). On the other hand, Principal Component Analysis (PCA) demonstrated a positive correlation between the most of chemical parameters and the fermentation period. The concentration of cadaverine and histamine has a positive association with the pH and type of bacteria producing the biogenic amines.

Electromagnetic fields effects on microbial growth in cocoa fermentation: A controlled experimental approach using established growth models

Understanding the effects of electromagnetic fields is crucial in the fermentation of cocoa beans, since through precise control of fermentation conditions the sensory and nutritional properties of cocoa beans could be improved. This study aimed to evaluate the effect of oscillating magnetic fields (OMF) on the kinetic growth of the core microbial communities of the Collections Castro Naranjal (CCN 51) cocoa bean. The data was obtained by three different models: Gompertz, Baranyi, and Logistic. The cocoa beans were subjected to different OMF strengths ranging from 0 mT to 80 mT for 1 h using the Helmholtz coil electromagnetic device. The viable microbial populations of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast (Y) were quantified using the colony-forming unit (CFU) counting method. The logistic model appropriately described the growth of LAB and Y under magnetic field exposure. Whereas the Baranyi model was suitable for describing AAB growth. The microbial populations in cocoa beans exposed to magnetic fields showed lower (maximum specific growth rate (μmax), values than untreated controls, with AAB exhibiting the highest average growth rate value at 5 mT and Y having the lowest average maximum growth rate value at 80 mT. The lower maximum specific growth rates and longer lag phases when exposed to magnetic fields compared to controls demonstrate the influence of magnetic fields on microbial growth kinetics.

VesiX cetylpyridinium chloride is rapidly bactericidal and reduces uropathogenic Escherichia coli bladder epithelial cell invasion in vitro.

When urinary tract infections (UTIs), which affect over 50% of women, become resistant to available antibiotic therapies dangerous complications like kidney infection and lethal sepsis can occur. New therapeutic paradigms are needed to expand our arsenal against these difficult to manage infections. Our study investigates VesiX, a Cetylpyridinium chloride (CPC)-based therapeutic, as a candidate broad-spectrum antimicrobial agent for use in bladder instillation therapy for antibiotic-resistant UTI. CPC is a cationic surfactant that is FDA-approved for use in mouthwashes and is used as a food additive but has not been extensively evaluated as a UTI therapeutic. Our study is the first to investigate its rapid bactericidal kinetics against diverse uropathogenic bacterial species isolated from postmenopausal women with recurrent UTI and host cytotoxicity. We also report that together with the FDA-approved bladder-instillation agent gentamicin, VesiX was able to significantly reduce intracellular populations of uropathogenic bacteria in cultured bladder epithelial cells.

Topical issues of therapy for patients with ulcerative colitis

Ulcerative colitis is an autoimmune disease characterized by ulcerative destructive processes in the mucous membrane of the colon. Despite advances in the pharmaceutical industry, its prevalence in the world is increasing every year. The etiology of UC is currently unknown to the end. According to modern concepts, ulcerative colitis is considered as a multifactorial disease, in the pathogenesis of which genetic determinism, disorders of the intestinal microbiota with a decrease in populations of anaerobic bacteria in combination with the trigger action of environmental factors are discussed. With high probability, the leading pathogenetic mechanisms of the disease are associated with the polarization of the Th2-type immune response, which is characterized by the synthesis of IL-4, IL-5, IL-9 and IL-13, which is regulated by STAT-5 and Gata-3. During the development of the disease, Th17, a type of immune response, is also involved in the immunopathological process, but with the participation of transcription factors STAT-3 and ROR-yt and the synthesis of IL-17, IL-2, IL-6, IL-26 and IL-22, as well as chemokine CCL20. Diet and lifestyle are part of the global guidelines for the treatment of patients with ulcerative colitis. Derivatives of 5-aminosalicylic acid are used as basic therapy preparations: combined preparations and preparations of pure 5-aminosalicylic acid. Nevertheless, the administration of systemic glucocorticosteroids is indicated to control the activity of the disease. However, as our practice shows, they are effective, but only at the first attack and subsequent 2-3 relapses of the disease, followed by a high incidence of hormone resistance. To date, there are modern medicines with a different mechanism of action, allowing achieving stable remission and improving the quality of life of patients. Among them, JAK -tofacitinib inhibitors are of particular interest in the treatment of ulcerative colitis. This is the first oral drug capable of inducing and maintaining steroidal remission. The choice of a particular drug is determined by the experience of use, cost and national recommendations.

Effect of Chitosan on Increasing Beneficial Soil Microflora and Disease Suppression in Turmeric Plants in Humid Tropics of Kerala, India

The present study assessed the population of nitrogen fixers and phosphate solubilizers in the rhizosphere, and suppression of leaf blotch disease caused by Taphrina maculans (Order: Taphrinales, Family: Taphrinaceae) in turmeric plants in response to chitosan application. Leaf blotch disease caused by Taphrina maculans has recorded upto 37.60 % to 52.90 % yield loss in turmeric. Hence, control measures have to be adopted. Chitosan is a biopolymer derived from chitin, which could evoke defense responses in plants. The treatments for this study included, foliar spray of chitosan 2 g L-1 at monthly intervals (F1), foliar spray of chitosan 4 g L-1 at bimonthly intervals (F2), soil drenching of chitosan 2 g L-1 at monthly interval (S1) and soil drenching of chitosan 4 g L-1 at bimonthly interval (S2). The untreated plants served as the control. The population of beneficial soil microbes were assessed and soil application of chitosan was observed to have better effect over foliar application with respect to the population of nitrogen fixing bacteria. More population of nitrogen fixing bacteria was recorded in the soil where chitosan 4 g L-1 was applied as soil drenching at bimonthly interval (S2). The population of phosphate solubilizers were significantly higher over the control in all the chitosan treatments irrespective of the mode of application. However, the higher population of phosphate solubilizers were observed, when chitosan 2 g L-1 was given as foliar spray at monthly intervals (F1). The chitosan treated plants were also observed to have significantly lower incidence of leaf blotch disease compared to control plants. The use of chitosan as a plant biostimulant protects the plant from soil borne pathogens and increases the population of beneficial soil microflora, which have a role in improving the nutrient uptake by plants thereby enhancing the plant growth and yield.

Model Simulation of Continuous Time Markov Chain Susceptible Infected Recovered-Bacterial Population for Cholera Disease

<p>Epidemic is an outbreak of an infectious disease rapidly in a population at a certain place and time. Epidemic models are used to explains the spread pattern of disease. The continuous time Markov chain susceptible infected recovered-bacterial population in the aquatic reservoir (CTMC SIR-B) model is a stochastic model, which considers the effect of bacterial population. The human population are classified into 3 groups. There are susceptible, infected, and recovered groups. Then, there are bacterial population which can infectious the cholera disease to human. CTMC SIR-B model considers treatment and water sanitation parameters. The spread of cholera disease can be modeled as CTMC SIR-B. Cholera is an acute intestinal infectious disease caused by the bacterium Vibrio cholerae. Cholera can be transmitted through the human digestive system. The symptoms of cholera disease are diarrhea, vomiting, and dehydration. The dehydration if not handled properly, may cause death. The aims of this research are to build and simulate the CTMC SIR-B model for cholera disease. The result of the model simulation shows that there is no significant difference between various values of treatment and water sanitation parameters. The pattern of the cholera disease spread describes that the transmission of cholera can occur from human to human even though there is no population of bacteria in the aquatic reservoir.</p><p><em></em><strong><em>Keywords</em></strong><strong><em>: </em></strong><em>cholera</em><em>; ctmc sir-b;</em><em> epidemic model</em><em>;</em><em> stochastic.</em></p><p> </p>

Biogas Slurry Significantly Improved Degraded Farmland Soil Quality and Promoted Capsicum spp. Production.

This study reports on the effects of pretreated biogas slurry on degraded farm soil properties, microflora and the production of Capsicum spp. The responses of soil properties, microorganisms and Capsicum spp. production to biogas slurry pretreated soil were determined. The biogas slurry pretreatment of degraded soil increases the total nitrogen (0.15-0.32 g/kg), total phosphorus (0.13-0.75 g/kg), available phosphorus (102.62-190.68 mg/kg), available potassium (78.94-140.31 mg/kg), organic carbon content (0.67-3.32 g/kg) and pH value of the soil, while the population, diversity and distribution of soil bacteria and fungi were significantly affected. Interestingly, soil ammonium nitrogen, soil pH and soil nitrate nitrogen were highly correlated with the population of bacteria and fungi present in the pretreated soil. The soil with biogas slurry pretreatment of 495 m3/hm2 favored the seedling survival rate, flowering rate and fruit-bearing rate of Capsicum spp. and significantly reduced the rate of rigid seedlings. In this study, the application of 495 m3/hm2 biogas slurry to pretreat degraded soil has achieved the multiple goals of biogas slurry valorization, soil biofertilization and preventing and controlling plant diseases caused by soil-borne pathogenic microorganisms. These findings are of significant importance for the safe and environmentally friendly application of biogas slurry for soil pretreatment.

Abstract B015: Toxin-producing bacterial therapy limits tumor growth in autochthonous mouse models of pancreatic ductal adenocarcinoma

Abstract Treating pancreatic ductal adenocarcinoma (PDAC) with systemic chemotherapeutic drugs has remained a challenge, due in part to the hypovascularized and poorly perfused nature of PDAC tumors, impeding the accumulation of systemically delivered drugs. Several clinical trials aimed at improving drug delivery in PDAC, through targeting of ECM components (HALO-301) or stromal angiogenic signaling (IPI-926-03) have unfortunately not been effective. However, the features that have interfered with systemic therapy in PDAC are potential advantages for the use of bacterial therapies, as bacteria can actively migrate through tissues, thrive in hypoxic microenvironments, and benefit from local immune suppression. Recent developments in the field of synthetic biology have made it possible to engineer complex logic circuits into bacteria, enabling the production of anticancer therapies directly within the tumor parenchyma. Furthermore, live bacteria, once colonized within the tumor niche, are capable of providing a stable source of anticancer compounds directly, rather than relying on repeated systemic doses. We have therefore worked to develop novel bacterial strains and demonstrate preclinical efficacy of a novel strain of therapeutic bacteria for targeting PDAC. We began by testing a range of bacteria-produced toxins and identified the pore-forming protein theta toxin as having the greatest effect in both 2D cell culture and PDAC explant (tissue slice) models. We then engineered a non-toxic probiotic bacteria, E. coli Nissle 1917, to produce either theta toxin or GFP. To assess preclinical efficacy, we performed intratumoral injections of live GFP- and theta-expressing bacteria into the “KPC” genetically engineered mouse model (Kras LSL.G12D/+; Tp53 LSL.R172H/+; PdxCre tg/+). While GFP-producing bacteria did not induce a change in tumor growth kinetics, treatment with theta toxin-producing bacteria demonstrated prolonged stabilization of tumor growth, increasing the median survival to 34 days compared to ~12 days for vehicle- or gemcitabine-treated controls and 18.5 days for GFP-producing bacteria without additional therapy. Strikingly, while there was minimal spread of bacteria to non-tumor tissues, we observed translocation of the bacteria to macro- and micro- metastatic lesions and distant papillomas following injection of the primary pancreatic tumor, indicating a mechanism for targeting both known and unknown metastases following local administration. Histological analyses demonstrated that diffuse populations of bacteria co-localized with regions of cell death, but that bacterial presence and evidence of increased cell death was not observed in healthy tissues, such as the lung, liver, intestine, and diaphragm. Additionally, bacterial treatment, independent of the payload, led to a modest influx of anti-tumor immune populations, suggesting potential synergy with immunotherapies. Together these data demonstrate potent preclinical activity of cytotoxic bacterial therapy as a novel strategy to circumvent the challenges of systemic treatment of PDAC. Citation Format: Amanda R. Decker-Farrell, Stephen A. Sastra, Tetsuhiro Harimoto, Marie C. Hasselluhn, Fangda Li, Rosa Vincent, Carmine F. Palermo, Edward R. Ballister, Tal Danino, Kenneth P. Olive. Toxin-producing bacterial therapy limits tumor growth in autochthonous mouse models of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B015.

Effects of Bacillus subtilis on the immune parameters, intestinal morphology and mucin gene expression in broilers exposed to Salmonella enterica challenge

The objective of this study was to evaluate the effect of the probiotic Bacillus subtilis supplementation on bacterial population, morphometry and mucin gene expression of intestine, and on immune response in Salmonella challenged broilers. Treatments were: 1) negative control (no probiotic- no challenging); 2) probiotic treated (no challenging); 3) positive control (no probiotic-salmonella challenging), and 4) Salmonella challenged chicks fed probiotic. Salmonella infection resulted in significant decrease in the relative weight of thymus. In challenged birds, dietary addition of probiotic increased (P<0.0.5) the relative weights of bursa and thymus. Population of lactic acid bacteria was significantly higher in probiotic treated groups as compared to negative control or challenged chickens. Challenged chickens had the lowest count of goblet cells and those received probiotic had the highest goblet cells count. The expression of mucin 2 gene was higher in group received dietary probiotic as compared with other treatments. Difference for gene expression was not found in challenged chickens and the negative control (P>0.05). In conclusion, the dietary inclusion of Bacillus subtilis could alleviate the negative effects of Salmonella infection on intestinal cells and bacterial population and could improve the growth and development of immune organs and function in infected broilers.

Short- to Medium-Term Corrosion of Mild Steel in Highly Calcareous Seawaters: Effects of Calcium Carbonate Concentration, Coupon Orientation, and Nutrient Addition

Mild steels exposed to marine immersion conditions in which carbonate solubilities are exceeded, leading to deposition of calcareous material, have been shown to exhibit much-reduced corrosion rates compared with corrosion under conditions in which there is no exceedance of solubility limits and therefore no calcareous deposition. However, the differences in corrosion including the potential effect of microbiologically influenced corrosion (MIC) in these conditions have not been examined systematically in the literature. The study reported herein involves short- to medium-term marine immersion exposures (up to 18 month) of mild steel coupons in natural seawater (control) and in environments using the same seawater source dosed with (1) CaCO3, acting as an inorganic particulate suspension representative of that encountered in seawater with elevated calcareous content; and (2) a nitrate salt, acting as an industrial pollutant and bacterial nutrient source. The results show the extent to which the deposition of particulate CaCO3 from suspension in seawater onto and into the rusts reduces the rate of corrosion of mild steel; a rate that was found to be dependent on the coupon orientation within the seawater. Coupons that were permanently buried beneath a cap of settled CaCO3 particles exhibited a 70% reduction in corrosion rate compared with the representative control coupons. The results also show that for these exposure durations and conditions, while iron-related bacteria and sulfate-reducing bacteria populations were identified in high concentrations (respectively ∼1 × 106 cfu/g and ∼1 × 102 to 4 × 106 cfu/g, depending on coupon orientation) within the rust products themselves after 18 month of exposure, there was no clear evidence of MIC. These findings indicate that short and medium-term (nonaccelerated) studies of MIC for mild steel are insufficient or even misleading for the prediction of long-term corrosion rates in these environments.