Minimal Nutrient Research Articles

Estimation of Staphylococcus total viable count in different contamination states of central venous catheters in hemodialysis centers based on tunable diode laser wavelength‐modulation spectroscopy

AbstractThe surveillance and assessment of the total viable count (TVC) of Staphylococcus under different levels of catheter contamination are crucial for the prevention and evaluation of catheter‐related infections in hemodialysis (HD). This paper demonstrates the noninvasive and accurate measurement of the TVC of Staphylococcus using wavelength‐modulated tunable diode laser absorption spectroscopy (WMAS). The tunable distributed feedback laser with a central wavelength of 2004 nm was employed and the detection limit of 22.5 ppm for carbon dioxide (CO2) produced by Staphylococcus epidermidis was obtained. The growth of Staphylococcus under different medium concentrations was studied, and the results indicated a strong correlation between the growth rate and final TVC of S. epidermidis with the medium concentration. When the degree of catheter contamination was low, resulting in minimal residual nutrient concentration within the catheter, the bacterial growth rate and TVC were effectively suppressed. Therefore, it is proven that WMAS is a user‐friendly, noninvasive, and high signal‐to‐noise ratio technique for monitoring Staphylococcus, making it an effective tool for assessing Staphylococcus growth in HD catheter surveillance.

Assessment of Integrated Poultry Manure and Synthetic Fertilizer Effects on Maize (Zea mays) Growth and Soil Properties: A Study from Bayero University, Kano

The study investigated the effects of organic and inorganic nutrients on crop productivity and soil health, with a focus on maize growth and soil properties. It was conducted at Bayero University, Kano and comprised six treatments laid out in a Completely Randomized Design (CRD) with three replications. The treatments included poultry manure, synthetic fertilizers, and their combination. The research aimed to assess the impact of these treatments on maize growth and their residual effects on soil physical and chemical properties. Various plant growth parameters and soil properties were evaluated, and the data obtained were analyzed using Analysis of Variance (ANOVA) and Student-Newman-Keuls test (SNK). The results indicated that all treatments significantly influenced morphological parameters, including plant height, number of leaves, stem girth, and leaf area, compared to the control. Maize growth was notably higher with the application of integrated poultry and inorganic fertilizer or solely inorganic fertilizers. Additionally, soil organic carbon, total nitrogen, phosphorus, and potassium contents increased when poultry manure was applied alone or in combination with inorganic fertilizer. The application of poultry manure significantly raised soil pH, organic carbon content, total nitrogen, available phosphorus, exchangeable potassium, calcium, magnesium, and effective cation exchange capacity (ECEC) of the soil. Furthermore, the exchangeable acidity of the soil was reduced by the application of poultry manure alone. Soil texture was improved, soil bulk density decreased, and porosity increased due to the application of poultry manure. The study concluded that the combined application of poultry manure and inorganic fertilizer enhanced the growth of maize and could serve as a good soil management practice for tropical soils. It also suggested that integrating inorganic fertilizers with organic manures at optimum rates could improve crop productivity on a sustainable basis. The findings of this study may contribute to the development of sustainable nutrient management programs aimed at enhancing crop productivity with high efficiency and minimal nutrient loss in the future.

Effects of postharvest management on the nutrient content of potato (Solanum tuberosum) tubers during storage

An experiment was performed to assess the effect of two plant powders and six storage methods on the proximate composition of potato tubers stored under ambient conditions to find a simple technology for storing potato tubers with a minimal nutrient degradation to reduce postharvest losses by smallholder farmers. Two plant powders and six storage methods were used in the study, which was designed as a 3 x 6 factorial experiment laid out in a completely randomized design (CRD) and replicated three times. The application of neem leaf powder to potato tubers and storage in the pit significantly (P ≤ 0.05) maintained protein (5.65%), fat (0.91%), fiber (0.75%), ash (2.70%), dry matter (30.63%), moisture (69.34%), and carbohydrate (20.62%) contents. Similarly, the pit storage method has influenced the nutrient content significantly (P ≤ 0.05) and is the best method for retaining protein (5.74%), fiber (0.78%), ash (2.81%), and moisture (69.83%) contents of potato tubers during storage under ambient conditions, and there is no significant (P > 0.05) interaction effect between the plant powder and the storage method. The study has found that the neem leaf powder and the pit storage significantly preserved the nutrient content of potato tubers during the four weeks of storage, which helped minimize postharvest losses. Keywords: basket, carton, floor, ginger, jute bag, neem, pit, polypropylene bag

Improving carbon management through maximizing hydrolysis and fermentation at water resource recovery facilities

Wastewater treatment plants are transitioning from a sole focus on treatment objectives to integrated resource recovery and upcycling. Effective carbon management is critical for upcycling within a water resource recovery facility (WRRF) to produce energy or other usable products, which involves carbon diversion at primary treatment and waste activated sludge (WAS) from biological treatment processes. Many WRRFs are also driven to meet stringent effluent nutrient discharge targets while minimizing energy usage and chemical addition. Nutrient removal systems still rely on biodegradable organic carbon to support denitrification and enhanced biological phosphorus removal (EBPR). Biological nutrient removal not only requires sufficient organic substrate, but also the right type of bioavailable carbon for optimal utilization. The main objective of this pilot fermentation testing was to evaluate the most effective utilization of the range of organic-carbon rich feedstocks within a WRRF. Preliminary results suggest that a 50–50 blend of primary sludge (PS) and return activated sludge (RAS) fermentation leads to highest volatile fatty acid (VFA) yield. PS fermentation resulted in the minimum nutrients release per unit of volatile suspended solids (VSS), which makes it a best suited for biological nutrients removal WRRFs with stringent nitrogen (N) and phosphorus (P) limits. The volatile fatty acids fractions produced from different combinations of RAS and PS can impact the most suitable end use for each sludge type fermentation. PS resulted into higher levels of propionate, which are ideal for selecting phosphate accumulating organisms (PAO) over glycogen-accumulating organisms (GAO). On the other hand, for denitrification, acetate is the preferred substrate, which was most abundant with RAS only fermentation. Our research outcomes will be of value to utilities aiming to integrate the stringent effluent nutrient (N and P) discharge targets with energy and resource recovery.

PSI-6 Growth performance of weaned pigs fed an activated zinc oxide to replace pharmacological content of dietary zinc oxide

Abstract The objective of this study was to determine the effect of replacing feed-grade zinc oxide (ZnO) with decreased contents of an activated zinc oxide (aZnO) on growth performance of weaned pigs. A total of 720 pigs (Landrace × Yorkshire × Duroc; TOPICS, Richfield, MN) with an initial body weight (BW) of 5.88 ± 0.97 kg were distributed into 60 pens with 12 pigs per pen following a randomized complete block design. After weaning at 18 d of age, pigs were fed one of five diets differing in ZnO source and Zn content during a 3-phase feeding program for 42 d (Table 1). Experimental diets were formulated to meet minimum nutrient requirements. Mortality was monitored daily and analyzed using survival analysis. Performance data were analyzed by multiple linear regression, with BW gain as dependent variable and Zn source (ZnO, aZnO) and Zn content as the independent variables for each phase. Linear regression analysis used diet A as baseline (150 ppm ZnO). In addition, groups receiving diet E and B, both supplemented with the same ZnO level during phase-1, were compared using a t-test. A linear relationship was observed between BW gain and dietary Zn content (P < 0.001) and Zn source (P = 0.026). A slope ratio between the two Zn sources indicated that pigs provided with aZnO had a 72% greater growth rate compared with ZnO. In addition, during Phase 1, when both diets B and E offered similar Zn concentrations (1,200 ppm) as ZnO and aZnO, pigs fed aZnO outperformed ZnO-fed pigs by 490 g (P < 0.001). The mortality was 7.6% less (P = 0.009) for diet C than diet A. No differences were detected among pigs fed the test diets in Phases 1, 2 and 3 for other variables. In conclusion, results show the potential of aZnO as a suitable replacement for ZnO, but also underscore the effect of dietary Zn content on pig performance and mortality. The aZnO source is a suitable replacement for ZnO, enhancing growth performance in weaned pigs and demonstrating potential for reducing overall Zn usage, thereby mitigating the environmental impact of swine production.

Phenotypic and genomic characterization of Methanothermobacter wolfeii strain BSEL, a CO2-capturing archaeon with minimal nutrient requirements.

A new variant of Methanothermobacter wolfeii was isolated from an anaerobic digester using enrichment cultivation in anaerobic conditions. The new isolate was taxonomically identified via 16S rRNA gene sequencing and tagged as M. wolfeii BSEL. The whole genome of the new variant was sequenced and de novo assembled. Genomic variations between the BSEL strain and the type strain were discovered, suggesting evolutionary adaptations of the BSEL strain that conferred advantages while growing under a low concentration of nutrients. M. wolfeii BSEL displayed the highest specific growth rate ever reported for the wolfeii species (0.27 ± 0.03 h-1) using carbon dioxide (CO2) as unique carbon source and hydrogen (H2) as electron donor. M. wolfeii BSEL grew at this rate in an environment with ammonium (NH4+) as sole nitrogen source. The minerals content required to cultivate the BSEL strain was relatively low and resembled the ionic background of tap water without mineral supplements. Optimum growth rate for the new isolate was observed at 64°C and pH 8.3. In this work, it was shown that wastewater from a wastewater treatment facility can be used as a low-cost alternative medium to cultivate M. wolfeii BSEL. Continuous gas fermentation fed with a synthetic biogas mimic along with H2 in a bubble column bioreactor using M. wolfeii BSEL as biocatalyst resulted in a CO2 conversion efficiency of 97% and a final methane (CH4) titer of 98.5%v, demonstrating the ability of the new strain for upgrading biogas to renewable natural gas.IMPORTANCEAs a methanogenic archaeon, Methanothermobacter wolfeii uses CO2 as electron acceptor, producing CH4 as final product. The metabolism of M. wolfeii can be harnessed to capture CO2 from industrial emissions, besides producing a drop-in renewable biofuel to substitute fossil natural gas. If used as biocatalyst in new-generation CO2 sequestration processes, M. wolfeii has the potential to accelerate the decarbonization of the energy generation sector, which is the biggest contributor of CO2 emissions worldwide. Nonetheless, the development of CO2 sequestration archaeal-based biotechnology is still limited by an uncertainty in the requirements to cultivate methanogenic archaea and the unknown longevity of archaeal cultures. In this study, we report the adaptation, isolation, and phenotypic characterization of a novel variant of M. wolfeii, which is capable of maximum growth with minimal nutrients input. Our findings demonstrate the potential of this variant for the production of renewable natural gas, paving the way for the development of more efficient and sustainable CO2 sequestration processes.

Lettuce evapotranspiration and crop coefficients using eddy covariance and remote sensing observations

AbstractLettuce (Lactuca sativa L.) is a high-value crop for irrigation districts in the low deserts of the USA Southwest. To ensure maximal crop quality, negligible soil salinity stress, minimal nutrient loss and reduced pathogen susceptibility, lettuce irrigation must meet, but not exceed, crop water use requirements. However, lettuce crop water use information is outdated in this region: prior studies were conducted at least four decades ago (1960–1980) and do not represent current varieties, management practices, and climate. To address this shortcoming, 12 commercial sites in Yuma, Arizona, USA were evaluated between 2016 and 2020 to update lettuce water use requirements and crop coefficients. The study measured crop evapotranspiration (ETc) using eddy covariance observations at eight iceberg and four romaine sites, where planting dates varied throughout the fall. Observed ETc and remote sensing data were used to model the daily soil water balance and derive crop coefficients: single (Kc), basal (Kcb), and soil evaporation (Ke). The analysis was supported by lettuce crop height estimates and fractional vegetative cover (fc) via remote sensing. Days to maturity averaged 75 ± 15 and 89 ± 12 days for romaine and iceberg, respectively, where season lengths increased as planting dates progressed from early fall to late winter. Average planting date for romaine sites was about 20 days earlier than average iceberg sites. When growing intervals are cast in heat units, dependence on crop type and time of planting was reduced. Average cumulative growing-degree-day and enhanced-degree-day metrics were 1133 ± 87 and 754 ± 48 °C-days, respectively. Seasonal lettuce ETc averaged 278 ± 24 mm. Cumulative irrigation applied, plus precipitation, averaged 355 ± 88 mm. Lettuce Kc for sites varied from 0.90 ± 0.13 to 1.19 ± 0.11 and Kcb from 0.20 ± 0.05 to 1.01 ± 0.11 for the initial and mid-season growth stages, respectively. These updates will help growers improve their irrigation efficiency for lettuce and provide important documentation needed by water managers.

Influence of Drip Fertigation and Foliar Spray of Boron on Yield and Nutrient Uptake by Cucumber cv. Himangi

The effect of fertigation and foliar application of boron on yield, uptake of nutrients and nutrient use efficiency by cucumber Cv. Himangi was studied during two consecutive years 2018-19 and 2019-20. An experiment was carried out in open field conditions with five fertigation levels viz., 100 % RDF through soil, 120 %, 100 %, 80 % and 60 % RDF through fertigation in ten equal splits at 10 days interval along with three levels of foliar application of boron viz. 0.0, 0.1, and 0.2 per cent concentration at 30, 45 and 60 DAS to determine suitable fertigation and foliar spray of boron dose for cucumber cultivation. The experiment was consisting of fifteen treatment combinations of recommended doses of water soluble fertilizers, comprising of five levels of fertigation. The results indicated that, yield, nutrient uptake and nutrient use efficiency of nitrogen, phosphorus and potassium under study were significantly influenced by various fertigation and boron levels. On the basis of pooled data, it was observed that, among various treatment combinations, minimum male : female sex ratio (1:4), maximum average weight of fruit (239.88 g), yield per vine ( 2.44 kg), yield ( 228.37 q/ha), uptake of nitrogen by shoot, ( 13.03 kg/ha), ( 81.62 kg/ha) by fruit and (94.01 kg/ha) by whole cucumber vine, maximum uptake of phosphorus by shoot (3.62 kg/ha), (21.52 kg/ha) by fruit and ( 25.13 kg/ha) by whole cucumber vine and the maximum uptake of potassium by shoot ( 14.05 kg/ha), by fruit (101.45 kg/ha) and ( 115.20 kg/ha) by whole cucumber vine, B:C ratio (2.99) and minimum (27.73, 25.71 and 17.2, 16.85 and 55.28, 50.28 %, respectively) nutrient use efficiency of NPK were recorded with the application of 120 % RDF through fertigation due to nutrient losses through leaching, devolatilization. While, maximum (36.70, 34.70 and 25.38, 21.90 and 65.81, 63.43 respectively) nutrient use efficiency of NPK was recorded with the application of 60 % RDF through fertigation. The maximum (22.59, 20.61 and 6.99, 7.70 and 27.30, 30.47 %, respectively) nutrient use efficiency with foliar application of boron at concentration of 0.2 per cent and minimum (3.60, 3.44 and 0.56, 0.52 and 3.72, 4.05 %, respectively) nutrient use efficiency with foliar application of boron at concentration of 0.1 per cent.

Spatial and temporal pattern of zooplankton assemblage in response to Limnological factors of river, Yamuna

Zooplankton plays a key role in maintaining aquatic ecosystem quality and is closely related with the community structure. During the present investigation, the zooplankton samples were collected from the three different sampling stations of River Yamuna for a period of one year from April 2012 to March 2013. The physico-chemical parameters of water such as temperature, transparency, velocity, turbidity, conductivity, pH, total alkalinity, total hardness, calcium, magnesium, dissolved oxygen, biological oxygen demand, phosphate and nitrate. The temperature ranged from 17.0±2.59 oC to 18.58±2.90oC and pH showed slightly alkaline nature. Sampling station, I registered a maximum dissolved oxygen concentration of 11.41±0.775 mg/l and minimum nutrient concentration. A total of 29 genera of zooplankton belonged to four different taxonomic groups were identified. Among these 10 genera belonged to protozoa, 11 genera belonged to rotifera, 6 genera belonged to copepod and 2 genera belonged to ostracoda. The zooplankton density was highest at sampling site I with maximum number of individuals belonging to all the four group. Rotifera formed the dominant group followed protozoa, copepoda and ostracoda. Daphnia, Asplanchna and Paramecium was reported with highest number of individuals during the entire study period. The total zooplanktonic richness generally indicated favorable environmental conditions and these were characterized by tolerant of widely fluctuating environmental conditions. Pearson correlation coefficient and Shannon- Weiner diversity index (H’) was calculated.

A modified animal-free serum technique for efficient isolation and proliferation of mesenchymal stem cells from Hoffa fat pad.

We focus on this study in designing an alternative technique for obtaining mesenchymal stem cells (MSCs) from residual tissue, Hoffa fat, in arthroscopic procedures. Two males and two females were included, and underwent knee arthroscopy; a sample of infrapatellar adipose tissue was obtained with basket forceps. The primary culture was made using the explant method and the culture media: DMEM-high glucose, supplemented with 10% of inactivated human allogeneic serum. All the cellular cultures remained under culture conditions for three weeks, after that by flow cytometry the cells were characterized by MSCs antibody panel: CD105, CD73 and CD90. Subsequently, in the first pass, the MSCs were cultured in commercial human chondrogenic, osteogenic and adipogenic mediums, respectively. After primary culture, we obtained on average 95,600.00 ± 7,233.26 cells/cm2, and the duplication time of MSCs isolate from Hoffa fat pad was established in 39 hours. By flow cytometry, we found that surface markers percentage for expanded MSCs (CD105, CD73, CD90) in primary culture significantly increased and its morphology was fibroblastic-like. After differentiation culture which was made in the first pass, by immunofluorescence, we obtained positive cell markers for three lineages of differentiation, adipocytes: LPL protein, osteocytes: RUNX2, Osteopontin, chondrocytes: SOX9, Aggrecan and COL2A1. We managed to isolate a significant number of MSCs from this source using an easy method to implement and minimal nutrient supplementation, with high potential for differentiation to mature mesenchymal tissues and potential use in basic experimental, preclinical and even clinical research.

Unlocking the potential of Chlamydomonas sp. for sustainable nutrient removal from POME: A biokinetic investigation

This study aimed to assess the capability of Chlamydomonas sp., for the treatment of palm oil mill effluent (POME), with a particular focus on nutrient removal efficacy. Batch cultivation experiments were conducted using Chlamydomonas sp. in bold basal medium (BBM) with varying POME concentrations. Biokinetic coefficients for nutrient removal were determined using the Michaelis-Menten equation. Over 16 days, Chlamydomonas sp. efficiently removed 100 % of ammonium (NH4+) and nitrate (NO3−), 66–89 % of phosphate (PO43−), and 16.7–33.2 % of chemical oxygen demand (COD). Experimental results and biokinetic coefficients highlighted the superior removal of NH4+ and PO43− by Chlamydomonas sp. in POME. For NH4+, the determined coefficients were k = 3.7161 mg NH4+ mg−1 DCW d−1, Km = 217.97 mg L−1, YN = 17.64 mg DCW mg−1 NH4+. For PO43−, the coefficients were k = 2.5413 mg PO43− mg−1 DCW d−1, Km = 131.53 mg L−1, YP = 12.91 mg DCW mg−1 PO43−. Chlamydomonas sp. biomass performed exceptionally well under low NH4+ and PO43− concentrations, requiring minimal nutrient input compared to COD and NO3−. In conclusion, Chlamydomonas sp. shows promise as an efficient and sustainable option for nutrient removal from POME and other wastewater sources, particularly those containing high levels of nitrogen and phosphate.

Local staples, and global solutions: optimizing the effect of traditional fermentation on heavy metals and mineral nutrients

PurposeThis study aims to examine the effect of traditional fermentation on gari’s total heavy metal and mineral nutrient content.Design/methodology/approachThis study used a quantitative approach, descriptive-analytical design to baseline the risk of heavy metals and experimental design to assess the effect of traditional fermentation. Data were analyzed using descriptives, univariate and multivariate analysis.FindingsAlthough gari is rich in mineral nutrients (total calcium 3.9 ± 0.1 g/kg, copper 5.5 ± 0.02 mg/kg, iron 97.1 ± 5.8 mg/kg, potassium 9.1 ± 0.29 g/kg and zinc 3.4 ± 0.11 mg/kg), the significant levels of heavy metals (total arsenic 1.2 ± 0.01, cadmium 2.5 ± 0.04, lead 1.7 ± 0.01, mercury 2.8 ± 0.01 and tin 1.7 ± 0.02 mg/kg) present are a cause for concern. The results further suggested that traditional fermentation has reductive effects on some heavy metals and stabilizing or concentrating effects on mineral nutrients.Research limitations/implicationsThis paper provides evidence that traditional fermentation may have exploitable differential effects on heavy metal contaminants and mineral nutrients that should be further explored.Practical implicationsThise study reports fermentation implications for mitigating food with high heavy metal contaminants with minimal nutrient loss.Originality/valueThis study fulfills an identified need to optimize traditional fermentation to ensure food safety and nutrient security.

Systematic framework to select the sustainable best design for an automated fertiliser blending system

The innovative device to automatically irrigate nutrients and water to the plants without affecting the environment has become increasingly important in sustainable agriculture and food production. This research aims to propose a prototype for a control-based Automated Fertiliser Blending System by investigating a comprehensive conceptual design framework and specific requirements from the market survey in designing the new device. The House of Quality, Morphological Chart, and Pugh tools were adopted to select the best conceptual design among the available design options. The approach of product design selection is based on ranking in engineering characteristics to generate design options. The benchmark design in this study is a timer system with two stock tanks. Conceptual Design 4 was selected as the advanced conceptual design because this system uses a Programmable Logic Controller to control the blending process of fertiliser solutions precisely with minimal nutrient loss and water runoff. A design prototype was developed for Design 4 using SolidWorks by considering all selection parameters of chosen criteria that were analysed based on the HOQ and Pugh methods. Conclusively, the proposed design of the Automated Fertilizer Blending System can provide technological innovation in designing this device. This will assist in coordinating better product development for potential product commercialization toward achieving sustainable and precise agriculture.

Effect of Agro-industrial Residue Composition on the Production of Endo-1, 4-β-Xylanase by Bacillus pumilus

Background: Bacillus pumilus grows on different substrates and produces Endo-1, 4-β-xylanase (EXase) which degrades the hemicellulose and produces xylooligosaccharides. EXase found applications in paper, pulp and in food industries. The objective of this study is to investigate the compositional effect of lignocellulosic biomass as substrate for the production of EXase by Bacillus pumilus. Methods: The EXase production depends on the composition of substrate (agro-industrial residue), Bacillus pumilus, media composition and performance of fermentation method. Thus, we have evaluated the effect of composition on the production of EXase. The higher content of hemicellulose of substrate indulges EXase production. Moreover, ICP-MS, FTIR spectroscopy, XRD and SEM analyses confirmed that significant alternation of substrate structure by Bacillus pumilus due to the EXase actions. Result: Based on the results of the hydrolytic enzyme activation and characterization studies suggested that Bacillus pumilus produced EXase highest for sugarcane bagasse 1190 U/mg by degrading the sugarcane bagasse as a low-cost carbon sources and effective media composition (Minimal Salt Yeast Extract Nutrient Medium) for nitrogen source, also with the presence of metal ions such as Cu++, Fe++, Mn++ for increased the production of EXase.

Coproduction of single cell protein and lipid from lignocellulose derived carbohydrates and inorganic ammonia salt with soluble ammonia recycling

Co-production of single cell protein (SCP) and lipid from lignocellulose-derived carbohydrates and inorganic ammonia offers a promising alternative for poultry or aquaculture feeds. An engineered oleaginous yeast Trichosporon cutaneum MP11 showed great potential for producing SCP and lipid from wheat straw and ammonia sulfate with minimum nutrient input. Trichosporon cutaneum MP11 showed stronger SCP and lipid fermentability using dry acid pretreated and biodetoxified wheat straw than using pure sugars. The residual ammonium sulfate in fermentation broth was recycled up to five times, resulting in ∼70% of nitrogen fixation into SCP. The overall yield of SCP and lipid from lignocellulose-derived sugars was 0.15 g/g and 0.11 g/g, respectively. This translates to the production of one ton of SCP (0.56 ton) and lipid (0.44 ton) from 6.6 tons of wheat straw, or one ton of SCP and lipid containing yeast cells (dry) from 4.8 tons of wheat straw.

Determination of minimal nutrient requirements for Tenebrio molitor growth and body composition

Determination of minimal nutrient requirements for Tenebrio molitor growth and body composition

Clostridioides difficile minimal nutrient requirements for flagellar motility.

As many gastro-intestinal pathogens, the majority of Clostridioides difficile strains express flagella together with a complete chemotaxis system. The resulting swimming motility is likely contributing to the colonization success of this important pathogen. In contrast to the well investigated general energy metabolism of C. difficile, little is known about the metabolic requirements for maintaining the ion motive force across the membrane, which in turn powers the flagellar motor. We studied here systematically the effect of various amino acids and carbohydrates on the swimming velocity of C. difficile using video microscopy in conjunction with a software based quantification of the swimming speed. Removal of individual amino acids from the medium identified proline and cysteine as the most important amino acids that power swimming motility. Glycine, which is as proline one of the few amino acids that are reduced in Stickland reactions, was not critical for swimming motility. This suggests that the ion motive force that powers the flagellar motor, is critically depending on proline reduction. A maximal and stable swimming motility was achieved with only four compounds, including the amino acids proline, cysteine and isoleucine together with a single, but interchangeable carbohydrate source such as glucose, succinate, mannose, ribose, pyruvate, trehalose, or ethanolamine. We expect that the identified "minimal motility medium" will be useful in future investigations on the flagellar motility and chemotactic behavior in C. difficile, particularly for the unambiguous identification of chemoattractants.

Cultivating the Mediterranean Wild Edible Species Cichorium spinosum L. in Aquaponics: Functional and Growth Responses to Minimal Nutrient Supplementation

Aquaponics is a plant and fish co-cultivation system with high sustainability, yet sub-optimal concentrations of Fe and K often compromise crop yields. We cultivated the Mediterranean wild edible Cichorium spinosum L. (Greek name: stamnagathi) in an aquaponics setup following a minimal supplementation approach that focused on Fe and K. Stamnagathi and tilapia fish were co-cultivated under (i) solely Fe, (ii) Fe+K input and (iii) no-input Control treatments. We aimed to evaluate the feasibility of aquaponics for stamnagathi cultivation, identify the system’s bottlenecks, and propose optimization measures. Several plant’s growth and functional parameters were monitored throughout the 35-day experimental period, notably instantaneous gas exchange and photosynthetic capacity via light response curves, state and efficiency of the photosynthetic machinery, pigment content, and yield and morphometric assessments. Fish growth characteristics and survival rates remained unaffected. Fe deficiency was crucial in shaping the responses of Control stamnagathi, which showed inferior performance in terms of photochemistry, chlorophylls content, light use efficiency and, subsequently, photosynthetic activity. Fe and Fe+K-treated plants exhibited similarly high performance in all studied parameters and achieved 4.5- and 4-fold increased yields, respectively, compared to Control. The results demonstrate that aquaponics is an advantageous cropping system for stamnagathi and solely Fe supplementation is adequate to promote excellent performance and yield of this oligotrophic species.

Spinach Responds to Minimal Nutrient Supplementation in Aquaponics by Up-Regulating Light Use Efficiency, Photochemistry, and Carboxylation

Aquaponics is a promising cultivation technique for combined production of crops and fish, on the condition of tackling certain nutrients deficiencies. The aim of the present study was to examine the limitations imposed by the system on spinach (Spinacia oleracea) growth and functional performance and to identify the minimum nutrient supplementation for their optimization. Spinach was co-cultivated with red tilapia under three treatments; iron (Fe) and iron with potassium (Fe+K) enrichment was compared with the no-external input control. During a 45-day experiment, the photosynthetic performance, photosynthetic machinery efficiency, total chlorophylls content, and leaf reflectance were monitored, along with leaf nutritional state, antioxidant activity, and growth responses of fish and crops. Control plants showed symptoms of Fe deficiency, extensive chlorosis, stunted growth, and functional impairment already from day 10. The latter consisted of a coordinated down-regulation of photochemistry, carboxylation, and light-use efficiency. Fe-treated plants exhibited similar growth and functional performance with Fe+K-treated plants but outperformed them in chlorophyll content, photosynthetic rates, and photochemical efficiency, mainly due to higher quantum yield of electron transport. Fish growth remained unaffected. Fe-deficiency was identified as the major bottleneck for spinach cultivation in closed-loop aquaponics, and our results demonstrate that only Fe supplementation may sufficiently improve spinach function and yield.

Determining the harvest frequency to maintain grassland productivity and minimum nutrient removal from soil

Determining the harvest frequency to maintain grassland productivity and minimum nutrient removal from soil