nutrient competition
Recently Published Documents


TOTAL DOCUMENTS

84
(FIVE YEARS 21)

H-INDEX

26
(FIVE YEARS 3)

2022 ◽  
Author(s):  
Jiajun Wu ◽  
David P. Keller ◽  
Andreas Oschlies

Abstract. In this study we investigate open-ocean macroalgae mariculture and sinking (MOS) as ocean-based carbon dioxide removal (CDR) method. Embedding a macroalgae model into an Earth system model, we simulate macroalgae mariculture in the open-ocean surface layer followed by fast sinking of the carbon-rich macroalgal biomass to the deep seafloor (depth > 3,000 m). We also test the combination of MOS with artificial upwelling (AU), which fertilizes the macroalgae by pumping nutrient-rich deeper water to the surface. The simulations are done under RCP4.5 a moderate emission pathway. When deployed globally between years 2020 and 2100, the simulated CDR potential of MOS is 270 PgC, which is further boosted by AU to 447 PgC. More than half of MOS-sequestered carbon retains in the ocean after cessation at year 2100 until year 3000. The major side effect of MOS on pelagic ecosystems is the reduction of phytoplankton net primary production (PNPP) due to the nutrient competition and canopy shading by macroalgae. MOS shrinks the mid layer oxygen minimum zones (OMZs) by reducing the organic matter export to, and remineralization in, subsurface and intermediate waters, while it creates new OMZs on the seafloor by oxygen consumption from remineralization of sunken biomass. MOS also impacts the global carbon cycle, reduces the atmospheric and terrestrial carbon reservoir when enhancing the ocean carbon reservoir. MOS also enriches the dissolved inorganic carbon in the deep ocean. Effects are mostly reversible after cessation of MOS, though recovery is not complete by year 3000. In a sensitivity experiment without remineralization of sunk MOS biomass, the entire MOS-captured carbon is permanently stored in the ocean, but the lack of remineralized nutrients causes a long-term nutrient decline in the surface layers and thus reduces PNPP. Our results suggest that MOS has a considerable potential as an ocean-based CDR method. However, MOS has inherent side effects on marine ecosystems and biogeochemistry, which will require a careful evaluation beyond this first idealized modeling study.


Author(s):  
Israr Khan ◽  
Yanrui Bai ◽  
Lajia Zha ◽  
Naeem Ullah ◽  
Habib Ullah ◽  
...  

The mammalian gut microbial community, known as the gut microbiota, comprises trillions of bacteria, which co-evolved with the host and has an important role in a variety of host functions that include nutrient acquisition, metabolism, and immunity development, and more importantly, it plays a critical role in the protection of the host from enteric infections associated with exogenous pathogens or indigenous pathobiont outgrowth that may result from healthy gut microbial community disruption. Microbiota evolves complex mechanisms to restrain pathogen growth, which included nutrient competition, competitive metabolic interactions, niche exclusion, and induction of host immune response, which are collectively termed colonization resistance. On the other hand, pathogens have also developed counterstrategies to expand their population and enhance their virulence to cope with the gut microbiota colonization resistance and cause infection. This review summarizes the available literature on the complex relationship occurring between the intestinal microbiota and enteric pathogens, describing how the gut microbiota can mediate colonization resistance against bacterial enteric infections and how bacterial enteropathogens can overcome this resistance as well as how the understanding of this complex interaction can inform future therapies against infectious diseases.


Author(s):  
George PLEŞ ◽  
Felix SCHLAGINTWEIT ◽  
Iuliana LAZĂR ◽  
Ioan I. BUCUR ◽  
Emanoil SĂSĂRAN ◽  
...  

A rich poriferan assemblage was identified within the easternmost part of the Getic Carbonate Platform of Romania (Grădiștei Gorges). The excellent preservation state of most poriferans here led to the discovery of a new species (Neuropora gigantea Pleș & Schlagintweit, n. sp.) and to the identification of previously unknown diagnostic features in some species (Sarsteinia babai Schlagintweit & Gawlick, 2006 emend., Neuropora lusitanica Termier, 1985, Sphaeractinia steinmanni Canavari, 1893). Calciagglutispongia yabei Reitner, 1992, Sarsteinia babai and Sphaeractinia steinmanni are reported for the first time from the Upper Jurassic carbonates of the Getic Carbonate Platform. The sedimentary input fluctuations and the nutrient competition had an important role in understanding the morphological adaptations of the analysed species. The existing palaeoecological and palaeoenvironmental conditions generated different distribution patterns towards the reef profile and also preferential adaptations to a specific Tethyan domain. As opposed to the poriferan assemblages from the northern Tethyan shelves, these organisms formed sponge-coral-microencruster boundstones at the margins and fore-reefal zones of isolated carbonate platforms within the intra-Tethyan realm. The importance of calcified sponges in reef-zonation is highlighted by the establishment of a general zonation model. Three zones can be distinguished: 1) Cladocoropsis-Milleporidium zone (back-reef area); 2) Bauneia-Chaetetopsis-Parastromatopora zone (central reef area); and 3) Sphaeractinia/Ellipsactinia-Neuropora zone for the fore-reef area. In the absence of a true reef framework these calcified sponges developed typical morphologies, environmental adaptations and partnerships with other biotic groups which strongly influenced the carbonate production throughout the intra-Tethyan domain.


2021 ◽  
Author(s):  
Iraes Rabbers ◽  
Willi Gottstein ◽  
Adam Feist ◽  
Bas Teusink ◽  
Frank Bruggeman ◽  
...  

Overflow metabolism is ubiquitous in nature, and it is often considered inefficient because it leads to a relatively low biomass yield per consumed carbon. This metabolic strategy has been described as advantageous because it supports high growth rates during nutrient competition. Here we experimentally evolved bacteria without nutrient competition by repeatedly growing and mixing millions of parallel batch cultures of E. coli. Each culture originated from a water-in-oil emulsion droplet seeded with a single cell. Unexpectedly we found that overflow metabolism (acetate production) did not change. Instead the numerical cell yield during the consumption of the accumulated acetate increased as a consequence of a reduction in cell size. Our experiments and a mathematical model show that fast growth and overflow metabolism followed by the consumption of the overflow metabolite, leads to a higher numerical cell yield and therefore a higher fitness compared to full respiration of the substrate. This provides an evolutionary scenario where overflow metabolism can be favourable even in the absence of nutrient competition.


Author(s):  
Filis Morina ◽  
Ana Mijovilovich ◽  
Igor Koloniuk ◽  
Aleš Pěnčík ◽  
Jiří Grúz ◽  
...  

Abstract To reveal the role of zinc in plant-pathogen interactions, soybean seedlings were grown hydroponically with a range of Zn concentrations, 0.06 (deficient, Zn0), 0.4 (optimal growth), 1.5, 4, 12 and 38 μM (toxic), and were subsequently inoculated with Phomopsis longicolla via the roots. P. longicolla is a hemi-biotroph fungus causing significant soybean yield loss worldwide. In vivo analyses of metal tissue-distribution by micro-X-ray fluorescence showed local Zn mobilization in the root maturation zone in all treatments 14 days post infection. Decreased root and pod biomass, and photosynthetic performance in infected Zn0.4 plants were accompanied by root Zn, jasmonoyl-L-isoleucine (JA-Ile), jasmonic acid, and cell wall-bound syringic acid (cwSyA) accumulation. In the Zn1.5 treatment, 7-fold higher root Zn concentration, JA-Ile, cwSyA, cell wall-bound vanilic acid and leaf jasmonates contributed to maintaining of photosynthesis and pod biomass under infection. Host-pathogen nutrient competition and phenolics accumulation could limit the infection in Zn-deficient plants. The low infection rate in Zn4-treated roots correlated with salicylic and 4-hydroxybenzoic acid, and cell wall-bound p-coumaric acid accumulation. Zn toxicity promoted pathogen invasion and depleted cell wall-bound phenolics. The results show that manipulation of Zn availability may improve soybean resistance to P. longicolla by stimulating phenolics biosynthesis and stress-inducible phytohormones.


Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1163
Author(s):  
Junen Wu ◽  
Huanhuan Zeng ◽  
Fan Zhao ◽  
Chunfeng Chen ◽  
Xiaojin Jiang ◽  
...  

Controversial competition theories may confuse the current understanding of belowground plant competition and thus result in incorrect diagnoses and mitigation strategies for nutrient competition. As such, the management of nutrient competition is a major challenge in the application and development of rubber agroforestry systems (AFSs). To explore the effects of plant competition on the nutrient status of rubber AFSs, this study measured the carbon, nitrogen, and phosphorus concentrations of the litter and soil and in plant leaves, stems, and roots from five rubber plantations (i.e., rubber monocultures and rubber mixed with cocoa, coffee, tea, and Flemingia macrophylla (Willd.) Merr., 1910)). The relative competition intensity indexes were calculated to evaluate the competition intensity of each mixed-species system, and Bayesian networks were established to investigate the linkage effects of interspecific competition for nutrients. This study demonstrated that rubber trees had weak competition with cocoa trees, moderate competition with F. macrophylla and tea trees, and intense competition with coffee trees. With the increase in competition intensity, the negative effects of interspecific competition on soil gradually offset the improvement in soil nutrients achieved with intercropping. Nitrogen and phosphorous translocation from the stems to the roots was enhanced by competition. However, enhanced nutrient allocation to roots may have led to insufficient nitrogen and phosphorous supplies in plant leaves. The quality of the litter therefore decreased because the nutrient status of fallen leaves determines the initial litter conditions. Such consequences may reduce the release of nutrients from the litter to the soil and thus increase soil nutrient depletion. This study revealed that competition effects were most obvious for the root nutrient status, followed by the stem and leaf nutrient statuses. Moreover, this study further demonstrated that the nutrient concentration of plant roots can better indicate the intensity of nutrient competition than the nutrient concentration of other plant organs.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zeyang Yu ◽  
Zhiying Wang ◽  
Yuzhou Zhang ◽  
Yucheng Wang ◽  
Zhihua Liu

Abstract The TabZIP15 gene encoding a 396 amino acid (aa) polypeptide in the fungus Trichoderma asperellum ACCC30536 was cloned and characterised. The protein includes a basic region motif (NR-x2-QR-x2-R) and has a pillar-like structure. The 25 basic region/leucine zipper transcription factors (TFs) identified in the T. asperellum genome were divided into YAP (14 TFs), ATF2 (5), GCN4 (2), Zip1 (2), BRLZ (1) and u1 (1) subfamilies based on conserved domains. T. asperellum was cultured in minimal media (MM) control, C-Hungry and N-Hungry medium (to simulate nutrient competition and interaction with pathogens, respectively), and differential expression analysis showed that 14 TabZIP genes (including TabZIP15) were significantly altered under both conditions; TabZIP23 responded strongly to N-Hungry media and TabZIP24 responded strongly to C-Hungry media. However, only YAP genes TabZIP15, TabZIP12 and TabZIP2 were significantly upregulated under both conditions, and expression levels of TabZIP15 were highest. T. asperellum was also cultured in the presence of five fungal pathogenic toxins, and RT-qPCR results showed that TabZIP15 was significantly upregulated in four of the five toxin stress conditions (MM + Rhizoctonia solani, MM + Fusarium oxysporum, MM + Alternaria alternata and MM + Cytospora chrysosperma).


2020 ◽  
Vol 21 (16) ◽  
pp. 5845
Author(s):  
Augusto Bleve ◽  
Barbara Durante ◽  
Antonio Sica ◽  
Francesca Maria Consonni

Cancer progression generates a chronic inflammatory state that dramatically influences hematopoiesis, originating different subsets of immune cells that can exert pro- or anti-tumor roles. Commitment towards one of these opposing phenotypes is driven by inflammatory and metabolic stimuli derived from the tumor-microenvironment (TME). Current immunotherapy protocols are based on the reprogramming of both specific and innate immune responses, in order to boost the intrinsic anti-tumoral activity of both compartments. Growing pre-clinical and clinical evidence highlights the key role of metabolism as a major influence on both immune and clinical responses of cancer patients. Indeed, nutrient competition (i.e., amino acids, glucose, fatty acids) between proliferating cancer cells and immune cells, together with inflammatory mediators, drastically affect the functionality of innate and adaptive immune cells, as well as their functional cross-talk. This review discusses new advances on the complex interplay between cancer-related inflammation, myeloid cell differentiation and lipid metabolism, highlighting the therapeutic potential of metabolic interventions as modulators of anticancer immune responses and catalysts of anticancer immunotherapy.


Metabolites ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 249
Author(s):  
Teresa W. -M. Fan ◽  
Richard M. Higashi ◽  
Yelena Chernayavskaya ◽  
Andrew N. Lane

The tumor microenvironment (TME) comprises complex interactions of multiple cell types that determines cell behavior and metabolism such as nutrient competition and immune suppression. We discuss the various types of heterogeneity that exist in solid tumors, and the complications this invokes for studies of TME. As human subjects and in vivo model systems are complex and difficult to manipulate, simpler 3D model systems that are compatible with flexible experimental control are necessary for studying metabolic regulation in TME. Stable Isotope Resolved Metabolomics (SIRM) is a valuable tool for tracing metabolic networks in complex systems, but at present does not directly address heterogeneous metabolism at the individual cell level. We compare the advantages and disadvantages of different model systems for SIRM experiments, with a focus on lung cancer cells, their interactions with macrophages and T cells, and their response to modulators in the immune microenvironment. We describe the experimental set up, illustrate results from 3D cultures and co-cultures of lung cancer cells with human macrophages, and outline strategies to address the heterogeneous TME.


Sign in / Sign up

Export Citation Format

Share Document