Co-option of an extracellular protease for transcriptional control of nutrient degradation in the fungus Aspergillus nidulans

Nutrient acquisition is essential for all organisms. Fungi regulate their metabolism according to environmental nutrient availability through elaborate transcription regulatory programs. In filamentous fungi, a highly conserved GATA transcription factor AreA and its co-repressor NmrA govern expression of genes involved in extracellular breakdown, uptake, and metabolism of nitrogen nutrients. Here, we show that the Aspergillus nidulans PnmB protease is a moonlighting protein with extracellular and intracellular functions for nitrogen acquisition and metabolism. PnmB serves not only as a secreted protease to degrade extracellular nutrients, but also as an intracellular protease to control the turnover of the co-repressor NmrA, accelerating AreA transcriptional activation upon nitrogen starvation. PnmB expression is controlled by AreA, which activates a positive feedback regulatory loop. Hence, we uncover a regulatory mechanism in the well-established controls determining the response to nitrogen starvation, revealing functional evolution of a protease gene for transcriptional regulation and extracellular nutrient breakdown.

Consistency of thresholds for eutrophication assessments, examples and recommendations

International harmonisation of management goals for eutrophication processes in coastal waters, requiring reduction of discharges and depositions of nutrients and organic matter, needs coordinated assessments and measures. This is especially necessary in open areas, connected by currents and mixing processes with trans-boundary exchanges. Management goals, defined nationally as local thresholds for nutrients and chlorophyll-a, had been applied recently (2006–2014) within international eutrophication assessments in the North Sea (OSPAR) and Baltic Sea (HELCOM). Consistency of thresholds for nitrogen nutrients and chlorophyll-a concentrations is tested by mixing diagrams and correlations between nitrogen nutrients (total and inorganic nitrogen) and chlorophyll-a. Results indicate mean consistent relations, but single deviations as in the continental coastal water of the North Sea surpassed means by a factor up to 5 for chlorophyll-a in relation to inorganic nitrogen. Thresholds differed across national borders significantly. Correlations of thresholds and assed data reflect the degree of regional deviations by comparison. Consistency of regionally applied thresholds can be achieved stepwise, by application of regionally correlated means, by adaptation to mixing and parameter relations, and finally by relations of thresholds to natural background concentrations. By this, consistency of international assessments can be improved generally, allowing coordinated management of open coastal waters.

Enhanced Autophagic Activity Improved the Root Growth and Nitrogen Utilization Ability of Apple Plants under Nitrogen Starvation

Autophagy is a conserved degradation pathway for recycling damaged organelles and aberrant proteins, and its important roles in plant adaptation to nutrient starvation have been generally reported. Previous studies found that overexpression of autophagy-related (ATG) gene MdATG10 enhanced the autophagic activity in apple roots and promoted their salt tolerance. The MdATG10 expression was induced by nitrogen depletion condition in both leaves and roots of apple plants. This study aimed to investigate the differences in the growth and physiological status between wild type and MdATG10-overexpressing apple plants in response to nitrogen starvation. A hydroponic system containing different nitrogen levels was used. The study found that the reduction in growth and nitrogen concentrations in different tissues caused by nitrogen starvation was relieved by MdATG10 overexpression. Further studies demonstrated the increased root growth and the higher nitrogen absorption and assimilation ability of transgenic plants. These characteristics contributed to the increased uptake of limited nitrogen nutrients by transgenic plants, which also reduced the starvation damage to the chloroplasts. Therefore, the MdATG10-overexpressing apple plants could maintain higher photosynthetic ability and possess better growth under nitrogen starvation stress.

A Panax notoginseng Root Tip Meristem Biosensor and Its Sensing Kinetics for Five Important Nitrogen Nutrients

Plants absorb nitrogen mainly through their roots. Nitrogen sensing is required for the absorption and transport of different nitrogen nutrients. In this study, we constructed biosensors with immobilized Panax notoginseng root tip meristems based on a three-electrode system and successfully determined the kinetics of the interactions between the P. notoginseng root tip meristems and five important nitrogen nutrients, namely, urea, sodium nitrate, sodium glutamate, disodium inosinate, and disodium guanylate. We discovered that the biosensor’s sensing kinetics was similar to the enzyme–substrate kinetics, and the receptor–ligand interconnected allosteric interaction constant Ka (mol/L), analogous to the Michaelis constant, was calculated. The result showed that the root tip meristems of two- to four-year-old P. notoginseng plants had a higher capacity to sense inorganic nitrogen nutrients (sodium nitrate and urea) than the three organic nitrogen nutrients. The ability of the plants to sense inorganic nitrogen nutrients decreased with an increase in plant age. The sensing sensitivity of four-year-old P. notoginseng plants to disodium inosinate and disodium guanylate was 100- to 10,000-fold lower than that of the two- and three-year-old plants. Additionally, the capability to sense sodium glutamate decreased initially and then increased with an increase in plant age. The biosensors reached an ultra-sensitive level ( 1 × 10 − 22 mol/L) in sensing the five nitrogen nutrients and exhibited advantages such as good stability and reproducibility, low cost, a simple structure, and a rapid response, providing a new approach for quantitative determination of the capability of plants to sense different nitrogen nutrients.

EFEK IRADIASI SINAR GAMMA PADA TANAMAN KACANG PENUTUP TANAH (Mucuna bracteata L.)

Legume cover crop (Mucuna bracteata L.) is a creeper which is currently often used to increase soil fertility in plantation areas. This plant is a leguminous plant that can fix nitrogen nutrients in the soil. One of the M.bracteata plant breeding programs to increase diversity is mutation using gamma ray radiation. The research objective was to determine the level of radiosensitivity of legume cover crop using gamma ray irradiation. The research was conducted at PAIR BATAN using a Gamma Chamber 4000A irradiator and in agricultural experiment, Labuhanbatu University. The plant material used was M.bracteata seeds with irradiation doses of 0, 200, 250, 300, 350 and 400 Gy. This study uses a curve fit analysis program to calculate the LD50 value (Lethal dose 50). The results showed that the plant radiosensitivity by calculating the LD50 value of M.bracteata at the age of 2 Weeks After Planting) was 348.737 Gy. The higher the radiation dose given, the lower the percentage of growth. Key words: diversity; leguminous; lethal dosage; mutation; gamma rays

ISOLASI DAN IDENTIFIKASI BAKTERI PENAMBAT NITROGEN UNTUK PEMBUATAN BIOFERTILIZER

Nitrogen is a macro nutrient needed by plants. Generally, people use inorganic fertilizers to fulfill nitrogen nutrients in plants. The problem then is, the continuous use of synthetic nitrogen fertilizers has a direct negative impact on the soil and a derivative impact on human health. The use of microorganisms, in this case bacteria, to provide nitrogen to plants can be done by isolating it and making it a biological fertilizer agent. Nitrogen fixing bacteria was isolated on the land of the oil palm plantation of PT Astra Agro Lestari. The isolated nitrogen-fixing bacteria were then tested quantitatively for their ability to fix nitrogen. The bacteria with the highest nitrogen fixing ability were then identified by sequencing their DNA nucleotide bases so that the bacterial strains were identified. The result is that there are 13 bacteria that are able to fix nitrogen with the codes J1, J3, Q5, L1, L11, J31, D1, M6, M5, R1, P2, J4 and C7. The quantitative test shows that bacteria with code D1 are the best at fixing nitrogen in the form of NH4, namely 0.27 ppm. The results of D1 bacterial DNA nucleotide base sequencing showed that the putitive Bacillus aerius strain 24K with identical values ​​and query cover reach

Transcriptional and Metabolic Response of Wine-Related Lactiplantibacillus plantarum to Different Conditions of Aeration and Nitrogen Availability

Lactic acid bacteria (LAB) perform the process of malolactic fermentation (MLF) in wine. Availability of oxygen and nitrogen nutrients could influence LAB growth, malolactic activity, and other metabolic pathways, impacting the subsequent wine quality. The impact of these two factors has received limited investigation within LAB, especially on a transcriptome level. The aim of this study was to evaluate metabolic changes in the strain Lactiplantibacillus plantarum IWBT B063, growing in synthetic grape juice medium (GJM) under different oxygen exposure conditions, and with low availability of nitrogen-based nutrients. Next-generation sequencing was used to analyze expression across the transcriptome (RNA-seq), in combination with conventional microbiological and chemical analysis. L. plantarum consumed the malic acid present in all the conditions evaluated, with a slight delay and impaired growth for nitrogen limitation and for anaerobiosis. Comparison of L. plantarum transcriptome during growth in GJM with and without O2 revealed differential expression of 148 functionally annotated genes, which were mostly involved in carbohydrate metabolism, genetic information processing, and signaling and cellular processes. In particular, genes with a protective role against oxidative stress and genes related to amino acid metabolism were differentially expressed. This study confirms the suitability of L. plantarum IWBT B063 to carry out MLF in different environmental conditions due to its potential adaption to the stress conditions tested and provides a better understanding of the genetic background of an industrially relevant strain.

Quantitative proteomics reveals the antifungal effect of canthin-6-one isolated from Ailanthus altissima against Fusarium oxysporum f. sp. cucumerinum in vitro

Canthin-6-one, one of the main alkaloid compounds extracted from Ailanthus altissima, has recently attracted increasing interest for its antifungal activity. To evaluate the potential of canthin-6-one in controlling plant fungal diseases, we investigated the antifungal activity of canthin-6-one isolated from A. altissima against Fusarium oxysporum f. sp. cucumerinum (Foc) in vitro. The mycelial growth rate and micro-broth dilution were used to test antifungal activity. Furthermore, label-free quantitative proteomics and parallel reaction monitoring (PRM) techniques were applied to analyze the antifungal mechanism. It was found that canthin-6-one significantly inhibited the growth of Foc, and had higher inhibitory action than chlorothalonil at the same concentration. Proteomic analysis showed that the expression of 203 proteins altered significantly after canthin-6-one treatment. These differentially expressed proteins were mainly involved in amino acid biosynthesis and nitrogen metabolism pathways. These results suggest that canthin-6-one significantly interferes with the metabolism of amino acids. Therefore, it affects nitrogen nutrients and disturbs the normal physiological processes of fungi, and ultimately leads to the death of pathogens. This study provides a natural plant antifungal agent and a new perspective for the study of antifungal mechanisms.

Effects of Shade and Biochar Application on the Quercetin Content of Longevity Spinach in Inceptisol

Traditional medicines have been used in both developed and developing countries for a long time, one of which is longevity spinach (Gynura procumbens). Its plants are one type of plant that is used by the community to treat various diseases with their flavonoid content. This plant produces various flavonoids, such as quercetin, which can be optimized by providing shade and increasing nitrogen nutrients by giving biochar and fertilizing. This study aimed to determine the effects of biochar, shade, and fertilizer on the growth and quercetin content of Gynura procumbens plants. This research was arranged in a randomized complete block design (RCBD) with two factors. The first factor was the administration of biochar at four doses, consisting of B0 (without biochar), B10 (biochar 10 tons/ha), B15 (biochar 15 tons/ha), and B20 (biochar 20 tons/ha). Meanwhile, the second factor was the intensity of the shade with three levels of treatment, namely, I0 (without shade), I50 (50%), and I70 (70%). The results showed that the addition of 15 ton/ha of biochar with 70% shade increased the quercetin content by 0.51%.

Águas Inseguras? Monitoramento da qualidade da água estocada em cisternas no semiárido paraibano

<p><span class="fontstyle0">Cisterns are alternatives that guarantee access to water in a decentralized manner. They have low environment impact and are economically viable in Brazilian semiarid. This study aimed to assess water quality stored in cisterns in a rural settlement in Cubati - semiarid of Paraíba. PH, electrical conductivity, total dissolved solids, salinity, color, turbidity, nitrogen nutrients and thermotolerant coliforms were monitored during the rainy (April and June / 2018) and dry (December / 2018) periods. The water stored in the cisterns comes from different sources between the hydrological periods, coming primarily from rainwater harvesting in the rainy season and from the supply of water trucks during the dry period. The waters, from all analyzed sources, did not present potable characteristics, presenting high values for color parameters (49.6 to 196.5 uC), turbidity (6.9 to 83.9 NTU), nitrate (2.2 10.2 mg / L), total coliforms and Escherichia coli. Thus, despite the storage of water in cisterns as a potential source of access to water for communities in the semiarid region, there is an evident need for treatment before its consumption, with rainwater harvesting being the most suitable source for more noble purposes such as drinking or cooking.</span> <br /><br /></p>