Days Of Incubation Research Articles

Influence of soil organic carbon fractions on the soil priming effect under different vegetation restoration modes

AbstractThe soil priming effect is a key mechanism influencing carbon (C) cycling processes between the forest soil organic carbon (SOC) pool and the atmosphere. Different vegetation restoration modes have different SOC pool compositions, and it is not clear whether such differences affect the soil priming effect. Therefore, we selected soil from six typical vegetation restoration modes Platycladus orientalis (PO), Pinus sylvestris (PS), Quercus acutissima (QA), shrub (SH) and wasteland (WL) in the soil and rocky mountainous areas of northern China and measured the soil properties, microbial communities, microbial necromass carbon (MNC), SOC fractions and the soil priming effect. The SOC content decreased in the order of PO (21.33 g kg−1), PS (22.00 g kg−1), QA (13.67 g kg−1), SH (13.33 g kg−1) and WL (10.33 g kg−1), and the trends of the mineral‐associated organic carbon (MAOC) and fungal necromass carbon (FNC) content were the same as those of the SOC content. The soil priming effect was greater in both forests and shrublands than in wastelands, with the greatest effect occurring in PO forests, where the soil priming effect reached 159.91 mg CO2‐C kg−1 soil after 30 days of incubation, which was 1.4 times greater than that in WL. The soil priming effect was mainly determined by the difference in MAOC content. In addition, the soil C/N ratio and bacterial community diversity also indirectly affected the soil priming effect by influencing the soil MNC and SOC fractions. Overall, afforestation increased the SOC content, fungal necromass contribution and mineral conservation, increasing the soil priming effect. This theoretical foundation supports the enhancement of SOC sequestration capacity by implementing various modes of vegetation restoration in the future.

Fabrication of GelMA - Agarose Based 3D Bioprinted Photocurable Hydrogel with In Vitro Cytocompatibility and Cells Mirroring Natural Keratocytes for Corneal Stromal Regeneration.

The complex anatomy of the cornea and the subsequent keratocyte-fibroblast transition have always made corneal stromal regeneration difficult. Recently, 3D printing has received considerable attentionin terms of fabrication of scaffoldswith precise dimension and pattern. In the current work, 3D printable polymer hydrogels made of GelMA/agarose are formulated and its rheological properties are evaluated. Despite the variation in agarose content, both the hydrogels exhibited G'>G'' modulus. A prototype for 3D stromal model is created using Solid Works software, mimicking the anatomy of an adult cornea. The fabrication of 3D-printed hydrogels is performed using pneumatic extrusion. The FTIR analysis speculated that the hydrogel is well crosslinked and established strong hydrogen bonding with each other, thus contributing to improved thermal and structural stability. The MTT analysis revealed a higher rate of cell proliferation on the hydrogels. The optical analysis carried out on the 14th day of incubation revealed that the hydrogels exhibit transparency matching with natural corneal stromal tissue. Specific protein marker expression confirmed the keratocyte phenotype and showed that the cells do not undergo terminal differentiation into stromal fibroblasts. The findings of this work point to the potential of GelMA/A hydrogels as a novel biomaterial for corneal stromal tissue engineering.

Comparison of Virulence and Quorum Sensing Gene Expression between Planktonic and Biofilm Cells of Legionella pneumophila

Abstract Legionella pneumophila is a waterborne bacterium that has a life cycle consisting of a transmissive phase in which free-living cells spread in the external environment, and a replicative phase with cells multiplying within biofilms. The transition from one phase to another is regulated by the bacterium’s quorum sensing system. As this system also regulates virulence, laboratory cultures of L. pneumophila were used to compare the different expressions of virulence and quorum sensing genes in planktonic and biofilm cells using RT-qPCR assays. The results showed a down regulation of the icmK gene in biofilm cells but only insignificant differences in the expression of 10 other genes associated with filamentation, conjugation, adherence and motility. The two quorum sensing genes examined, lpg1057 and lpg2731, differed in their expression profiles in planktonic and biofilm cells. While their expression in planktonic cells increased from day 10 until day 15 of incubation, their expression in biofilm cells steadily declined after 10 days of incubation. This decrease in quorum sensing gene expression was shown to be associated with a decrease in cell density in the biofilm, thus suggesting that the trigger for the transition from the replicative phase to the transmissive phase is likely to be nutrient depletion in the biofilm.

Higher biodegradation rate of atrazine by Paenarthrobacter sp. KN0901 with P-doped hydrochar: The important role of biofilm regulated by autoinducer-2 regulated quorum sensing during the degradation process

The presence of atrazine residue in runoff from agricultural areas poses a significant risk to the ecosystem. This study aimed to develop microorganism-material systems using the atrazine-degrading strain Paenarthrobacter sp. KN0901 and P-doped hydrochar to effectively remove atrazine residues from aquatic environments. The atrazine degradation rate increased by 22.6 % with the addition of P-doped hydrochar after three days of incubation at 15 °C. Autoinducer-2 activity increased from 100 % to 116.7 % with P-doped hydrochar addition, indicating improved quorum sensing compared to free microorganisms. The extracellular polymeric substance content was significantly higher in the PHC groups compared to the blank groups, suggesting enhanced biofilm formation. Quorum sensing was inhibited by the use of nitazoxanide and sodium nitroprusside, leading to decreased atrazine degradation. In contrast, the presence of glucose and S-adenosyl methionine enhanced the rate of atrazine degradation due to elevated quorum sensing. These results suggested that P-doped hydrochar enhanced strain KN0901′s ability to assemble, increasing quorum sensing and accelerating atrazine degradation. Additionally, P-doped hydrochar promoted atrazine degradation by strain KN0901 under various conditions by enhancing quorum sensing. This work offers a new perspective on developing and using bioremediation techniques to remediate atrazine-contaminated environments under diverse conditions.

Enhancing infection control in dialysis at a resource limited public healthcare institute: A cross-sectional study on microbiological quality assessment of dialysis water and dialysate

PurposeTo evaluate the microbiological quality of dialysis water and dialysate samples from hemodialysis units at a tertiary care government hospital and to assess the use of culture, endotoxin and periodicity of testing these assays to guide the actions of monitoring the quality of hemodialysis fluids, implement preventive and corrective actions, and improve the safety and outcomes of the dialysis process. MethodsA cross-sectional study was conducted at a 250-bedded super-specialty government hospital with a 24/7 hemodialysis unit equipped with 40 dialysis machines. Dialysis water and dialysate samples were collected monthly and analysed for microbial contamination and endotoxin levels as per AAMI guidelines. Bacterial cultures were done using Reasoner's Agar plates, and endotoxin analysis was performed using gel clot assay. Interpretation of results was based on predefined thresholds. ResultsAmong the 740 samples processed for microbial culture 19.6 % and 80.4% were unacceptable and acceptable respectively.Among the acceptable samples 10.5 % were at action level. At the end of 2 days of incubation, 15.2%dialysis water samples and 5.1%dialysate samples had unacceptable levels of bacterial colonies and at 5days additional 10.6 % dialysis water samples and 7.7%dialysate samples were unacceptable. 21.5 % of the samples tested for endotoxin had unacceptable levels. ConclusionsRegular monitoring of water quality in government healthcare hemodialysis units is crucial for quality of care, timely preventive and corrective actions for mitigating adverse outcomes. Processing cultures for 5–7 days is essential for detecting all contaminated specimens. While there might be a link between endotoxin levels and bacterial contamination, both endotoxin testing and bacterial culture independently are vital for evaluating water quality in dialysis settings. A comprehensive approach integrating various testing methods is necessary to uphold patient safety and enable necessary improvements.

Efficiency-enhancing methods for predicting nitrogen mineralization characteristics in paddy soils using soil properties and rapid soil extraction

Soil mineralized nitrogen (N) is a vital component of soil N supply capacity and an important N source for rice growth. Unveiling N mineralization (Nm) process characteristics and developing a simple and effective approach to evaluate soil Nm are imperative to guide N fertilizer application and enhance its efficiency in various paddy soils with different physicochemical properties. Soil properties are important driving factors contributing to soil Nm differences and must be considered to achieve effective N management. Nevertheless, discrepancies in Nm capacity and other key influencing factors remain uncertain. To address this knowledge gap, this study collected 52 paddy soil samples from Taihu Lake Basin, south China, which possesses vastly different physicochemical properties. The samples were subjected to a submerged anaerobic incubation experiment at a constant temperature to obtain the soil Nm characteristics. In addition to other analyses, reaction kinetics models were employed to compare characteristic differences between Nm potential (Nmp) and short-term accumulated mineralized N (Amn) processes in relation to soil physicochemical properties. Based on these relationships, simplified Nmp prediction methods for paddy soils were established. The results revealed that the Nmp values in pH < 6.50, pH range from 6.50 to 7.50, and pH > 7.50 were 145.18 mg kg-1, 88.64 mg kg-1 and 21.03 mg kg-1, respectively. Significantly, after comparing different incubation days, short-term Amn at 14 days showed a good correlation (P < 0.01) with Nmp (R2 = 0.94), indicating that the prevailing short-term incubation experiment is an acceptable marker for Nmp. Moreover, Nmp correlated well with the ultraviolet absorbance obtained at 260 nm using NaHCO3 extraction (Na260), streamlining the Nmp estimation method further. The incorporating easily obtainable soil properties, including pH, total nitrogen (TN), and the ratio of total organic carbon to TN (C/N) alongside Na260 for Nmp evaluation allowed the multiple regression model, Nmp = 58.62 × TN - 23.18 × pH + 13.08 × C/N +86.96 × Na260, to achieve high predictive accuracy (R2 = 0.95). The reliability of this prediction was further validated with published data in paddy soil from the same region and the other rice regions, demonstrating the regional applicability and prospects of this model. This study underscored the roles of soil properties in Nm characteristics and mechanisms and established a site-specific prediction model based on rapid extraction and edaphic properties from the paddy soil, paving the way for developing rapid, precise Nm prediction models.

Specialization of Alcanivorax species in colonizing diverse plastics.

Recently, there has been increased attention to hydrocarbonoclastic bacteria in the plastisphere. One particular genus, Alcanivorax, is reported in the biodegradation of several polymers in the literature. In this study, we further explored the role of Alcanivorax in the early colonization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), nylon 6/69, and a novel plastic B4PF01. Starting from enrichments of a one-year experiment with a maximum relative abundance of 58.8% of Alcanivorax, two parallel experiments were set up. One experiment followed growth and activity during the first 21 days of plastic incubations, and the other followed the same parameters on the different material fractions of the plastics, such as leachables and pure polymer. For all plastic types, the highest microbial growth was associated with the total plastics compared to the other material fractions. A relative abundance of 62.7% of Alcanivorax in the nylon 6/69-enriched community was observed. This, combined with data on activity, suggests that nylon 6/69 is potentially degraded by this genus. Two isolates were obtained, closely related to A. borkumensis SK2 and Alcanivorax sp. DG881. The activity and growth of the isolates as axenic cultures resemble their abundance in the community. In conclusion, this study contributes to the knowledge of the role of Alcanivorax in plastic-enriched communities.

Long‐Term Effects of Arable and Tree Cropping Systems on Soil Organic Carbon and Nitrogen Dynamics in a Tropical Agroecological Transition Zone

ABSTRACTContinuous cropping can affect soil carbon and nitrogen stocks and litter decomposition, but research on smallholder farms in Africa is limited. This study, conducted from 2020 to 2023 in Ghana's forest‐savanna transition zone, examined four cropping systems: continuous maize monocrop (M), maize rotated with legumes (ML), young cashew intercropped with maize or legumes (YCM/L), and mature cashew (MC). The objective was to assess the long‐term impact of the cropping systems on soil organic carbon (SOC), nitrogen (N) stocks, and soil organic matter (SOM) decomposition rates using the tea bag protocol. Results showed significant variability in SOC and N stocks across the systems. At a 0–15 cm depth, SOC in the MC and M systems was 160% and 149% higher than in the YCM/L system. At 15–30 cm, SOC in the M and MC systems was 86% and 132% higher than in YCM/L. Soil nitrogen stocks followed a similar trend, with MC and M systems showing 94%–199% higher values than YCM/L at both depths. SOM decomposition rates for green and rooibos tea in the MC and ML systems were statistically similar after 90 days of incubation (p &gt; 0.05). This study, the first to use the tea bag protocol in Ghanaian soils, revealed that mature cashew and sustainable practices, such as adding maize stover, can enhance SOC and N stocks in highly weathered tropical soils. These findings underscore the potential for specific cropping systems to improve soil health on smallholder farms.

Effect of Humic Acids Extracted From Different Organic Sources and Inoculation of Bacillus Subtilis or Aspergillus Niger in Alkaline Phosphatase Activity in Calcareous Soil

Humic acids have received a large attention of researching and development as amendments for poor fertility conditions and deteriorating physical properties, since the process of extracting is an easy common process to implement, as well as dilution of these acids with water enables to be used at economically acceptable levels over large areas. It is necessary to notice that the properties of these acids depending on the organic source and the concentration added to the soil.A laboratory experiment was conducted at the department of soil Sciences and water resources, collage of Agriculture ,University of Basrah ,Iraq to demonstrate the effect of humic acids extracted from different sources and inoculation with Bacillus subtilis or Aspergillus niger on alkaline phosphatase activity in calcareous soil calcareous, southern Iraq. Humic acids extracted from wheat straw, alfalfa leaves, goat manure, and poultry manure which composted previously . Humic acid levels were 0, 25 and 50 L ha-1 .The soil also inoculated with Bacillus subtilis or Aspergillus niger, then samples were incubated at 28±2°C. After 7 or 30 days of incubation the activity of alkaline phosphatase was estimated . Enzyme phosphatase activity was increased in soils treated with humic acid as compared to control with highest activity at Poultry manure (391.54 µg p-nitrophenol gm-1 soil.1h-1).The results also indicated that increasing the level of humic acid significantly increased enzyme activity. For soil treated with Bacillus subtilis and Aspergillus niger , phosphatase activity increased-as compared to control with a higher activity at Bacilluas subtilis (373.1 µg p-nitrophenol gm-1 soil.1h-1).

Sustained co-release of ciprofloxacin and dexamethasone in rabbit maxillary sinus using polyvinyl alcohol-based hydrogel microparticle

Topical delivery to paranasal sinuses through sustained-release stents is one of the new horizons in treating chronic rhinosinusitis (CRS). This study aims to introduce and evaluate sustained co-release of encapsulated ciprofloxacin (CIP) and dexamethasone (DEX) in polyvinyl alcohol-based carriers within the maxillary sinus of rabbit animals. DEX and CIP were loaded in a tyramine-substituted polyvinyl alcohol microparticle (PVATyr MP). The mechanical stability, degradability, and sustained-release patterns of both drugs as well as cellular cytocompatibility were assessed in vitro. The PVATyr MPs were then injected into the maxillary sinus of rabbits and they were monitored weekly for 21 days. Nasal endoscopy, MRI imaging, and tissue microscopy were used to follow the changes and compared them with the control condition. Also, the concentrations of drugs were evaluated in the maxillary sinus and blood samples over the study period. Produced PVA-based MPs possessed a relatively narrow particle size distribution (CV 7.7%) with proper physical stability until 30 days of incubation. The uniform-sized PVATyr MPs and their surrounding hydrogel showed sustained-release profiles for DEX and CIP for up to 32 days in vitro. The injected drugs-loaded hydrogel showed complete clearance from the maxillary sinus of rabbits within 28 days. The concentrations of DEX and CIP in mucosal remained within the therapeutic window when measured on days 7, 14, and 21, which were well above the plasma concentrations without any pathological changes in endoscopy, MRI imaging, and histological examinations. DEX/CIP loaded PVATyr MPs provided an effective, controlled, and safe sustained-drug delivery in both in vitro and in vivo analyses at therapeutic concentrations with minimal systemic absorption, suggesting a promising treatment approach for CRS.Graphical

Effects of Metribuzin on Soil Microbiome and Weed Management Under Varying Planting Practices and Potato Seed Dormancy

AbstractWeed infestation in potato field has become a major concern to smallholder farmers and environment, requiring sustainable intervention. This study aimed to determine (i) whether metribuzin application rate (0, 0.5, 1 (standard), 1.5, and 2 kg ai ha−1) has effects on soil microbes and soil nutrients in the short term using potted soil and (ii) the influence of potato seed dormancy (short; Shangi variety and long; Unica variety) and planting technique (surface, ridge, or furrow planting) on the efficacy of weed management practice (metribuzin (480 g L−1) herbicide and hoeing) in the field. Bacterial colony counts were recorded upon isolation from the potted soil. Soil nutrients were also analysed before and after metribuzin treatment. Data on crop growth (height and stem count), weed abundance, yield, costs, and revenues were recorded from a field experiment. Morphologically distinct bacterial strains were tested for Gram reaction and response to carbon utilization using analytical profile index kits (API 50 CH and 20 NE). In total, nine distinct bacterial strains were isolated and all were Gram positive, with variation in response to carbon substrates. Concentration of 2.0 kg a.i ha−1 significantly (p ≤ 0.05) reduced bacterial count in the first day, followed by an increase in the subsequent incubation days, while 1.0 and 1.5 kg a.i ha−1 concentrations had the highest colony development index and species richness. Significant effects of metribuzin on soil pH, total N, and total organic C in the short term were revealed. Notably, weedy plots had the highest Shannon weed index. Weeds reduced stem count and height growth by 57% and 62% respectively. Plots with Shangi had 9.8% lower weed count than those with Unica and hence higher yield was recorded from the former. While surface planting had the lowest weed control efficacy, crop growth attributes, and yield, furrow and ridge planting were not significantly different. Weed abundance and crop growth attributes in metribuzin and hand-hoed plots did not differ significantly, yet hoeing resulted in 5.30 t ha−1 above that obtained from plots managed using metribuzin. Higher dry matter and tuber yield were observed from hoed plots with Shangi planted in furrow or ridge. Use of metribuzin resulted in higher net benefit ratio and marginal rate of return than hand hoeing. The results reveal that use of metribuzin early and later in the potato growing phase can minimize weed infestation, but the efficacy depends on planting method and seed dormancy.

Unravelling of cellulolytic fungal consortium from humus soil for efficient lignocellulosic waste degradation

Cellulose is a complex polysaccharide composed of β 1, 4 glycosidic linkages and these linkages are broken down by a complex enzyme system called cellulase. Cellulase is an enzyme complex associated with β 1, 4 endoglucanase, β 1, 4 exoglucanase, and β glucosidase. The fungal strains were isolated from decomposed humus soil and screened for the best cellulolytic activity. Thirty-two isolates were screened among these; three were selected based on their morphological characters and hydrolytic capacity, viz, Cladosporium oxysporum N5, Aspergillus sigurros N6, and Cladosporium cladosporioides N12. Among these fungi, Cladosporium oxysporum N5 shows potential hydrolytic activity and was selected for optimization studies and evaluation of their cellulolytic capability. Cellulolytic strain Cladosporium oxysporum N5 produced maximum amount of cellulase enzyme at 5 days of incubation at 30 ℃ and pH 7, viz, β 1, 4 endoglucanase (167.83± U/ml), β 1, 4 exoglucanase (29.04± U/ml), and β glucosidase (34.07± U/ml). SEM coupled Energy dispersive X-ray and FTIR spectroscopy methods revealed the cellulose degradation efficiency of fungal cellulase by microscopic, elemental percentage, and functional group, respectively. An affordable and eco-friendly fungal-based cellulase that will boost industrially important commodity production such as food, beverages, pharmaceuticals, fertilisers, and biofuels.

Effects of Microplastics and Organic Fertilizer Regulation on Soil Dissolved Organic Matter Evolution.

Microplastics are pollutants of global concern nowadays. However, the effects of microplastics addition to soil as a carbon source and the combined effects of microplastics and organic fertilizer on soil-dissolved organic matter (DOM) evolution are still unclear. This study focused on the evolution of DOM in soil with the addition of microplastics and investigated the variations in the content and composition of DOM in unfertilized and fertilized soil with different particle sizes of microplastics. It was observed that the TOC concentration of the soil DOM in the treatment with organic fertilizer and microplastics increased more (129.97-161.43 mg kg-1) than that in the treatment with microplastics alone (117.17-131.87 mg kg-1) and was higher than that in the original soil (95.65 mg kg-1). According to the humic acid relative abundance in DOM after 40 days of incubation, the humic acid relative abundance in DOM of the soil samples with microplastics and organic fertilizers addition was found to be higher than that in those with microplastic addition alone, reaching more than 80% in a short time. In conclusion, the TOC concentration of the soil DOM increased with the addition of microplastics, and the increase was more pronounced when organic fertilizers and microplastics were added together. Moreover, the soil humification increased to a higher level in the short term with the combined addition of microplastics and organic fertilizers, which was maintained during the long-term incubation process.

Harnessing Bacillus safensis as biofertilizer for sustainable drought alleviation in Brassica juncea L

Carrier-based biofertilizers, which involve the introduction of plant growth-promoting bacteria into agricultural industry waste materials, are gaining increasing attention due to their profoundly positive impacts on soil health. In current study, various carriers, including dry leaves, sugarcane husk (SCH), rice husk (RH), and a combination/Mixture (MIX) of all three, were employed to support the bacterial strain, Bacillus safensis (SCAL1). This strain was utilized as a bioinoculant in the production of carrier-based biofertilizers. This particular strain was sourced from the Environmental and Microbial Botany Lab at Quaid-i-Azam University in Islamabad. Bacillus safensis strain exhibited notable improvements, evident in a high rate of longevity and larger colony-forming units within the carriers, as confirmed by measurements taken after 21 days of incubation. The drought stress was induced using polyethylene glycol solutions with concentrations of 15% and 25% administrated 6 and 15 days after germination, respectively. Four distinct biofertilizer types were formulated in the study: DL + SCAL1, RH + SCAL1, SCH + SCAL1, and MIX + SCAL1. When applied to Brassica juncea L. plants, all of these biofertilizers demonstrated the ability to mitigate drought stress and enhance the quality of Brassica juncea L. The immobilization onto SCAL1 by using SCH showed the best result compared to the liquid inoculum as carrier materials improve stability and shelf life. Furthermore, our results affirmed that carrier-based biofertilizers improved biochemical and physiological attributes of plants during drought conditions, highlighting their importance as a valuable resource for mitigating drought stress in Brassica juncea L. The findings revealed that carrier-based biofertilizers are an excellent source of diverse phytohormones, which are pivotal in alleviating drought stress.

Fate of As(V) and Cr(VI) adsorbed on goethite in a mangrove‐microcosm experiment

AbstractMangroves provide fundamental ecosystem services; however, the growing impact of human activities has resulted in increased pollution pressure, such as chemical contaminants. The redox processes are major biogeochemical players in the fate of contaminants. We investigate the effects of the redox environment on As(V) and Cr(VI) adsorbed on goethite (i.e., Fe(III)‐oxide) over 40 days of incubation in columns containing mangrove soil subjected to seawater saturation cycles. Our spectroscopic data highlighted a less Fe(III)‐ordered arrangement on goethite over time; As(V) is strongly bound to goethite, which delayed until 20 days its remobilization and reduction to As(III). After 40 days, the goethite held ∼50% of the initial As, but it was 15% as As(III). On the other hand, Cr(VI) was desorbed almost completely in less than 10 days, and the residual Cr ions bound to goethite were almost totally converted to Cr(III). Our study stresses the importance of individual time‐dependence in evaluating chemical speciation changes among potential toxic elements in wetland systems, such as mangroves and artificial wetlands designed to water treatment or soil remediation.

Effects of Thermal Manipulation During the Second Half of Incubation on Embryo Physiology, Hatching Parameters, and Quality of Broiler Chickens in Tropical Climate of Togo

Chickens are sensitive to environmental challenges caused by temperature. The current study aimed to determine the effects of heat manipulation during embryonic development on the physiological responses of Goliath chickens. A total of 2000 hatching eggs from 48-week-old breeders were weighed, numbered, and randomly distributed equally into 4 incubators. Each incubator received 500 eggs (4 replicates of 125 eggs each). Eggs in two of the incubators were rotated hourly at a 45° angle and maintained at 37.8°C and 60% relative humidity (T0 groups). Between embryonic days (ED) 10 and 18 of incubation, the eggs from the other two incubators were heated to 38.5°C for 6 hours per day (T1 groups). The eggs were reweighed and candled, and viable eggs were moved to the hatching baskets at ED 18 of incubation. Hatching eggs were examined individually for hatching events every three hours during the final three days of incubation. On day 21, blood samples were collected from 12 chicks per group for hormonal and biochemical analyses. The evaluated blood parameters included Triiodothyronine (T3), T4 (thyroxine), cortisol, uric acid, lactate dehydrogenase, and total protein. At hatch, chicks were weighed and their quality (survival after hatching and performance standards) was evaluated. Data were collected on embryonic development, hatching window, hatching events, biochemical parameters, and hormonal concentrations. Results indicated that hatchability, chick’s weight, Tri-iodothyronine, and corticosterone were higher in the T1 group, compared to the control group. At hatch on day 21, the pipping muscle of chicks in the treated group (T1) was significantly heavier than that of the control group, while the embryonic mortality rate was significantly higher in the T0 group. In conclusion, applying heat treatment for 6 hours at 38.5°C from ED10-ED18 of embryogenesis increased significantly the hatching rate, the pipping muscle, and the chick’s weight in this study. Keywords: Embryonic development, Physiology, Slow-growing broiler, Thermal manipulation, Tropical climate

Molecular phylogenetic characterization of L-asparaginase-producing endophytic fungi inhabiting Prunus africana and Periploca linearifolia: Effect of incubation time and pH on enzyme production

The therapeutic use of L-asparaginase derived from bacterial sources has been constrained by various challenges, including toxicity and repression. This has prompted the exploration of alternative sources, particularly eukaryotic microorganisms like fungi, to enhance the safety and effectiveness of the L-asparaginase enzyme. This study aims to investigate the fungal endophytes inhabiting Periploca linearifolia and Prunus africana as a potential source of novel L-asparaginase. Additionally, the study seeks to examine the impact of incubation time and pH on L-asparaginase production. Standard surface sterilization techniques were used for isolation of endophytic fungi. Based on the research findings, 24 % of the fungal endophytes demonstrated a positive reaction for L-ASNase activity and were identified as Colletotrichum sydowii, Fusarium sporotrichioides, Fusarium solani, Cercospora canescens, Penicillium crustosum, Penicillium pancosmium, Phoma sp, Penicillium ubiquetum, septoria sp and Penicillium commune. A significant variation in the production of L-asparaginase based on the time of incubation and pH was observed. Most endophytic fungal isolates exhibit optimal enzyme activity on the 6th day of incubation. However, both Septoria sp and Colletotrichum sydowii recorded the highest L-asparaginase activity on the 9th day of incubation. Fusarium solani demonstrated peak activity of 12.4 ± 1.12 UI/mL on the 12th day of incubation. The optimal pH for L-asparaginase production by fungal endophytes was found to be between 5 and 6. The fungal endophytes isolated from medicinal plants have the potential to serve as sources of novel L-asparaginase. Furthermore, it is evident that fungal endophytes display considerable variation in L-asparaginase production, influenced by the duration of incubation and pH conditions.

Effect of in ovo feeding with a multi-strain probiotic containing effective microorganisms and Zn-Gly chelate on the fatty acid profile, lipid profile, and malondialdehyde level in the serum and tissues of newly-hatched chickens

Modern poultry production strives to ensure the safety of food products by constantly improving the health parameters of birds. Multi-strain probiotics containing effective microorganisms and microelements, especially zinc in chelated form, currently play an important role in poultry feeding. We hypothesized that supplementation of chicken embryos with a multi-strain probiotic and glycine-zinc chelate may influence lipid metabolism in the serum and tissues of newly hatched chicks, leading to an increase in the body's antioxidant capacity. Therefore, the aim of the study was to assess the lipid profile, fatty acid profile and malondialdehyde (MDA) concentration in the serum and tissues of newly hatched chickens supplemented in ovo with a multi-strain probiotic and zinc glycine chelate. The experiment was conducted on 1,500 fertilized hatching eggs obtained from 36-week-old commercial broilers (Ross x Ross 308). A multi-strain probiotic and zinc glycine chelate (Zn-Gly) were administered on the 17th day of incubation. Samples of peripheral blood and tissues of the liver, small intestine (ileum), pectoral muscle, thigh muscle and yolk sac, collected on the day of hatch and at 7 days post-hatch, were used to analyse biochemical parameters and determine the malondialdehyde level and fatty acid profile. The results indicate that in ovo supplementation with a multi-strain probiotic and Zn-Gly chelate on the 17th day of incubation affects fat metabolism. Simultaneous administration of a multi-strain probiotic and Zn-Gly chelate did not increase the concentration of polyunsaturated fatty acids (PUFAs) in the muscles. In birds treated with Zn-Gly chelate, the PUFA concentration was increased in the muscle tissue in the period up to 7 days post-hatch, i.e. during the development of the chicks. Moreover, the analysis of the results confirmed that in ovo supplementation with a multi-strain probiotic and Zn-Gly chelate stimulates the synthesis of saturated fatty acids (SFAs), mainly stearic, palmitic and myristic acids, and improves the ratio of PUFAs to SFAs. The multi-strain probiotic and Zn-Gly chelate administered in ovo did not cause excessive MDA synthesis in the tissues, suggesting that these preparations reduce oxidative stress in the developing embryo and newly hatched chick.

The effect of low-temperature plasma pretreatment on the biodegradability of polyethylene films

ABSTRACT With the increasing focus on environmental friendliness and sustainable development, extensive research has been conducted on the biodegradation of plastics. The non-hydrolyzable, highly hydrophobic, and high-molecular-weight properties of polyethylene (PE) pose challenges for cell interaction and biodegradation of PE substrates. To overcome these obstacles, PE films were treated with low-temperature plasma before biodegradation. The morphology, surface chemistry, molecular weight, and weight loss of PE films after plasma treatment and biodegradation were studied. The plasma treatment decreased the surface water contact angle, formed C–O and C = O groups, and decreased the molecular weight of PE films. With the increased pretreatment time, the biodegradation efficiency rose to 2.6% from 0.63% after 20 days of incubation. The mechanism was proposed that the surface oxygen-containing groups formed by plasma treatment can facilitate the bio-accessibility and be further decomposed and utilised by the microbes. This study provided an effective and rapid pretreatment strategy for improving biodegradation of PE.

Effect of Temperature, Relative Humidity, and Incubation Time on the Mycotoxin Production by Fusarium spp. Responsible for Dry Rot in Potato Tubers.

Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3-10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (aw; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and aw enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 106 ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 aw. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety.