Higher Growth Efficiency Research Articles

Stable cytoactivity of piscine satellite cells in rice bran-gelatin hydrogel scaffold of cultured meat

In order to achieve high cell adhesion and growth efficiency on scaffolds for cultured meat, animal materials, especially gelatin, are necessary though the disadvantages of weak mechanical properties and poor stability of their hydrogel scaffolds are present during cell cultivation. Here, we use rice bran as a kind of filling and supporting materials to develop a composite scaffold with gelatin for fish cell cultivation, where rice bran is also inexpensive from high yield fibrous agricultural by-product. The rice bran (with a proportion of 1, 3, 5, 7, 10 to 3 of gelatin) could evenly distributed in the three-dimensional network composed of gelatin hydrogel. It contributed to delaying swelling and degradation rates, fixing water and improving elastic modulus. It is important that rice bran-gelatin hydrogel scaffolds (especially the hydrogel with 70 % rice bran, db) promoted piscine satellite cells (PSCs) proliferation effectively compared to the pure gelatin hydrogel, and the former could also support the differentiation of PSCs. Overall, this work showed a positive promotion to explore new source of scaffold materials like agricultural by-product for reducing the cost of cell cultured meat production.

Mostly solidified hardground at the top of the crystal pile in the Bushveld magma chamber

Mafic layered intrusions show abundant evidence for the formation through the progressive inwards growth of a mushy solidification layer, with a central body of nearly crystal-free resident melt. The thickness and permeability of the mushy layer play a vital role in operation of several petrogenetic processes but remain poorly constrained in layered intrusions. To address this issue, we have re-examined the cumulate sequence in the Upper and Critical Zones of the Bushveld Complex. Although some observations (e.g., soft-sediment deformation) are indicative of cumulate rocks being mushy and having experienced interstitial melt percolation (e.g., metasomatic anorthosites), other field and textural evidence suggest the contrary. Some of the clearest evidence comes from sections through chromitite and magnetitite layers as well as through the Merensky Reef, layers that were deposited on the eroded rocks of the temporary chamber floor. Below the erosional surface, the layered rocks (1) were tilted and truncated without losing their internal coherence, (2) have knife-sharp contacts with the overlying rocks, (3) show minimal evidence of penetration by downward-percolating melt, (4) reveal sharp truncation of individual crystals, particularly beheading of pyroxene oikocrysts and intersecting of polysynthetic twinning in plagioclase, and (5) show resumed growth on the truncated crystals into the overlying rocks. These observations indicate that the cumulates of the inward-growing chamber floor were almost entirely solid at the time of the erosion and deposition of these layers. To reconcile these two sets of contrasting observations, we propose that only a few metres of the uppermost portion of the cumulate pile of the Upper and Critical Zones of Bushveld magma chamber were mushy, with other underlying rocks being almost totally solidified. The mushy layer tends to be thin and locally even non-existent (e.g., in magnetitite layers) due to high efficiency of primary adcumulus growth at the crystal-liquid interface of the temporary chamber floor. The solid chamber floor results from thermochemical erosion of the entire mushy layer by magmas replenishing the evolving chamber. The study implies that such petrogenetic processes as the hydrodynamic sorting of crystals and reactive porous flow may only operate within this very thin mushy portion of the cumulate pile and cannot therefore be responsible for any large-scale petrological features (e.g., platinum reefs, massive chromitites, stratiform anorthosite layers) of the Bushveld Complex.

Pulse feeding and pulse growth: a highly adaptive strategy of heterotrophic dinoflagellates Oxyrrhis marina

Pulse feeding and growth of the Black Sea strain of dinof lagellates Oxyrrhis marina (Dujardin, 1841) (OXY–IBSS), equivalent spherical diameter (ESD) (23.5 ± 3.1 mm) have been studied under experimental conditions simulating phytoplankton blooms. Microalgae Phaeodactylum tricornutum (P, ESD 3.4 ±0.3 mm), Isochrysis galbana (I, ESD 3.7 ± 0.4 mm), Tetraselmis suecica (T, ESD 6.1 ± 0.9 mm), and Rhodomonas salina (R, 7.4 ± 0.7 µm) were used as food objects in a one-component and three-component suspensions. Microalgae concentrations (~106 cells/mL for T and R; up to ~4 × 106 cells/mL for P and I) were chosen to ensure their equal total carbon biomass ~0.02 mg C/mL in the food mixtures at the beginning of the experiment. Under ad libitum conditions, the maximum clearance rates of the OXY–IBSS reached 0.1–0.5 mL ind./day, and the grazing rate of microalgae was 34–44 cells/(ind h) for P and I, and 2–11 cells/(ind. h) for R and T, respectively. The grazing rate of microalgae in carbon units was significantly higher when feeding on I (3.9 ng C/(ind. day)) and significantly less when fed with a mixture of microalgae TRP (1.5 ng C/(ind. day)). Maximum abundance of OXY–IBSS, achieved within 3 or 4 days (by the time the microalgae concentration decreased below threshold), varied from 19 × 103 ind./mL (P) to 43 × 103 ind./mL (I). In the absence of food, dinof lagellates O. marina turned to cannibalism, and within 4 days the oscillating f luctuations (within 50%) in their number took place. Although the specific population growth rate (m, day-1) of OXY–IBSS was higher when feeding on small cells (~2 days–1 on I), the gross growth efficiency (GGE) of OXY–IBSS was significantly higher when fed on large (T and R) microalgae (26–29% vs. 14–15%). At lower daily rations (DRs) when fed with the mixture TRP, the GGE of OXY–IBSS was significantly higher (41%) when compared to other nutritional conditions. The feeding strategy of opportunistic predator O. marina on diverse (in terms of size and chemotaxonomic characteristics) mixtures of prey lay in a f lexible choice between high specific population growth rate, or high gross growth efficiency, that obviously gives the populations of this species the advantages over other protists under conditions of the pulsed phytoplankton blooms.

Synergistic bioconversion of organic waste by black soldier fly (Hermetia illucens) larvae and thermophilic cellulose-degrading bacteria.

This study examines the optimum conversion of Wuzhishan pig manure by Black Soldier Fly Larvae (BSFL) at various phases of development, as well as the impact of gut microbiota on conversion efficiency. In terms of conversion efficiency, BSFL outperformed the growing pig stage (GP) group, with significantly higher survival rates (96.75%), fresh weight (0.23 g), and larval conversion rate (19.96%) compared to the other groups. Notably, the GP group showed significant dry matter reductions (43.27%) and improved feed conversion rates (2.17). Nutritional composition varied, with the GP group having a lower organic carbon content. High throughput 16S rRNA sequencing revealed unique profiles, with the GP group exhibiting an excess of Lactobacillus and Clostridium. Promising cellulose-degrading bacteria in pig manure and BSFL intestines, including Bacillus cereus and Bacillus subtilis, showed superior cellulose degradation capabilities. The synergy of these thermophilic bacteria with BSFL greatly increased conversion efficiency. The BSFL1-10 group demonstrated high growth and conversion efficiency under specific conditions, with remarkable larval moisture content (71.11%), residual moisture content (63.20%), and waste reduction rate (42.28%). This study sheds light on the optimal stages for BSFL conversion of pig manure, gut microbiota dynamics, promising thermophilic cellulose-degrading bacteria, and the significant enhancement of efficiency through synergistic interactions. These findings hold great potential for sustainable waste management and efficient biomass conversion, contributing to environmental preservation and resource recovery.

High efficiency of boron doping and fast growth realized with a novel gas inlet structure in diamond microwave plasma chemical vapor deposition system

High efficiency of boron doping and fast growth realized with a novel gas inlet structure in diamond microwave plasma chemical vapor deposition system

Modulation effects of different dissolved nitrogen compositions on the phytoplankton community structure based on combined field experiments and the NbPD model in Jiaozhou Bay

The dissolved nitrogen (DN) regime in Jiaozhou Bay (JB) has shifted recently, and the phytoplankton community structure showed decreased diatom and increased dinoflagellate concentrations. This study combined field microcosm experiments, the Nutrients–bi-Phytoplankton–Detritus (NbPD) biogeochemical model, and statistical analysis, and obtained some results. The growth/death of dominant phytoplankton populations were comprehensively determined by the processes of nutrient uptake, excretion and decomposition of phytoplankton in JB. Kinetic parameters indicated that Skeletonema costatum preferentially absorbed NH4-N and NO3-N, while Protoperidinium pellucidum preferentially absorbed domestic-derived dissolved organic nitrogen. Moreover, S. costatum, as R-strategists, needed a faster uptake rate and slower excretion rate to achieve high growth efficiency but with faster decomposition, while P. pellucidum, as K-strategists, could maintain stability with a more active metabolism. Overall, this study discussed the key factors modulating the diatom dinoflagellate community structure changes in JB, providing a scientific basis for ecosystem-based management.

Optimal Dietary Protein/Energy Ratio and Phosphorus Level on Water Quality and Output for a Hybrid Grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀) Recirculating Aquaculture System

In a recirculating aquaculture system (RAS), feed is critical to the growth of fish and is the main source of nutrient pollutants in aquaculture water. An eight-week feeding trial was conducted to investigate the role of feed on the growth efficiency of hybrid grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀) and water quality in a RAS. Five commercial feeds with different respective dietary protein/energy (P/E) ratios and available phosphorus levels were selected (LNLP, 31.97 g/MJ, 0.96%; LNMP, 32.11 g/MJ, 1.54%; MNLP, 36.26 g/MJ, 0.98%; MNMP, 36.53 g/MJ, 1.58%; and HNP, 41.54 g/MJ, 1.97%). The results showed that HNP had the highest growth efficiency and MNLP provided the best economic benefit. The trend in water quality within 6 h after feeding was similar among the five groups. The relative concentrations of ammonia nitrogen, total nitrogen, active phosphate, and total phosphorus reached a maximum 2 h after feeding, and the relative concentration of nitrite reached a maximum 1 h after feeding. The high P/E ratio feed increased the concentrations of total ammonia nitrogen and nitrite nitrogen. The total ammonia nitrogen concentration in HNP was much higher than those in the other treatments. The dietary P/E ratio had no significant effect on total nitrogen concentration. High dietary phosphorus levels increased the total phosphorus concentration in the water, but no significant effect on the active phosphate concentration was observed. Considering the growth efficiency, economic benefit, and water quality, it can be concluded that MNLP is the most suitable feed for RAS breeding hybrid grouper. The results of this study supplement the gap on the effects of feed on RAS water quality and provide data support for the sustainable development of RAS industry.

Bioaugmentation performance for moving bed biofilm reactor (MBBR) treating mariculture wastewater by an isolated novel halophilic heterotrophic nitrification aerobic denitrification (HNAD) strain (Zobellella B307)

Moving bed biofilm reactor (MBBR) demonstrates weak nitrogen removal for mariculture wastewater treatment under high salinity environment. An isolated novel halophilic heterotrophic nitrification aerobic denitrification (HNAD) strain (Zobellella B307) was applied in MBBR process to enhance nitrogen removal. Results showed that strain Zobellella B307 could remove 90.9% ammonia nitrogen (NH4+-N) and 97.1% nitrate nitrogen (NO3−-N) after 10 h cultivation, and strong resistance to salinity variation (high growth and nitrogen removal efficiency with salinity of 65‰) was observed. Besides, the chemical oxygen demand (COD), NH4+-N and NO3−-N removal reached 95.6%, 94.4% and 85.7% with the strain added into MBBR process. In addition, microbial community structure analysis reflected that the strain Zobellella B307 successfully proliferated (the relative abundance increased to 2.33%). The HNAD bacteria abundance increased and dominated during the nitrogen removal process with the strain inoculation. A microbial functional analysis revealed that the main dominant functional categories (carbohydrate metabolism and amino acid metabolism) increased with the bioaugmentation of strain Zobellella B307, thus improving the nitrogen removal.

Effect of Seed Pretreatment Methods on Germination and Early Seedling Growth of Senna spectabilis

The objectives of the study were to evaluate the effect of pretreatment methods on germination of Senna spectabilis seed and determine the effect of pretreatment methods on height and root collar diameter growth of Senna spectabilis seedlings. The experimental treatments involved were control; seeds soaked in cold water for 12 h, 24 h, and 48 h; seeds soaked in hot water and allowed to cool for 12 h, 24 h, and 48 h; and nicked seeds using secateurs. The experiment was arranged in a completely randomized design (CRD) with four replications. The data variables assessed were seedling height, root collar diameter, and survival rate. Data were subjected to one-way ANOVA using Minitab software. Results showed that there were significant differences p ≤ 0. 05 among treatment means on germination, seedling height, and root collar diameter, while the survival rate was not statistically significant p ≥ 0.05 . Nicked seeds and those soaked in hot water and allowed to cool for 12 h had an outstanding performance in terms of germination and seedling growth. It is, therefore, recommended that farmers should be encouraged to use nicked and hot water soaked for 12 h seed in order to achieve high germination and growth efficiencies in their homestead gardens.

Calculation Model of Regional Economic Growth Efficiency by Intelligently Optimized Interunit Layout.

With the development of the economy, especially since the reform and opening up, the actual conditions that China's economic development faces have also changed, and the development goals have also been adjusted accordingly. However, since the reform and opening up, China's economy has still largely relied on the extended reproduction of the extension type. It basically develops along a high-input, low-efficiency path. The effectiveness of regional economic development has always been one of the most important debates in economics, and it has attracted great attention in different countries and regions around the world. So far, people have conducted a lot of theoretical and practical research on the effectiveness of regional development and put forward many practical countermeasures. However, it has achieved little in practice, and the original form of high growth and low efficiency has not been effectively reversed. In this paper, economic development is divided into two parts. The first part consists of the impact of changes in the quantity of factors of production on economic growth and the impact of the efficiency of economic growth on the entire economy. The second part consists of the annual average efficiency of economic growth. The average annual contribution of various production factors to economic growth and the economic growth efficiency of changes in the allocation of capital industries were 6.21%, 5.02%, 4.05%, 3.9%, and 3.3%, respectively in the past five years.

Fishmeal Dietary Replacement Up to 50%: A Comparative Study of Two Insect Meals for Rainbow Trout (Oncorhynchus mykiss).

Simple SummaryThe reduction of dependence on fishmeal as a main protein source for aquafeeds remains a big problem in reaching sustainable aquaculture. Several alternatives to this ingredient are being tested and developed, insects being one of the most promising. The present study included two different insect species (black soldier fly, Hermetia illucens, and yellow mealworm, Tenebrio molitor) in the formulation of diets for rainbow trout (Oncorhynchus mykiss) against one typical fishmeal-based diet. Different parameters related to both the efficiency of these diets and their physiological repercussions were analysed. Yellow mealworm proved to be the best alternative for the growth and nutrition of rainbow trout, possibly due to some changes described in protein utilization and intestine histology, while other parameters revealed the possible usage of insect meals as functional ingredients due to their repercussions on preventing tissue damage.The demand of optimal protein for human consumption is growing. The Food and Agriculture Organization (FAO) has highlighted aquaculture as one of the most promising alternatives for this protein supply gap due to the high efficiency of fish growth. However, aquaculture has been facing its own sustainability problem, because its high demand for protein has been traditionally satisfied with the use of fishmeal (FM) as the main source. Some of the most promising and sustainable protein substitutes for FM come from insects. The present manuscript provides insight into an experiment carried out on rainbow trout (Oncorhynchus mykiss) with a 50% replacement of FM with different larvae insect meals: Hermetia illucens (HI), and Tenebrio molitor (TM). TM showed better results for growth, protein utilization and more active digestive function, supported by intestinal histological changes. Liver histology and intermediary metabolism did not show relevant changes between insect meals, while other parameters such as antioxidant enzyme activities and tissue damage indicators showed the potential of insect meals as functional ingredients.

The carbon and nitrogen budget of Desmophyllum dianthus-a voracious cold-water coral thriving in an acidified Patagonian fjord.

In the North Patagonian fjord region, the cold-water coral (CWC) Desmophyllum dianthus occurs in high densities, in spite of low pH and aragonite saturation. If and how these conditions affect the energy demand of the corals is so far unknown. In a laboratory experiment, we investigated the carbon and nitrogen (C, N) budget of D. dianthus from Comau Fjord under three feeding scenarios: (1) live fjord zooplankton (100–2,300 µm), (2) live fjord zooplankton plus krill (>7 mm), and (3) four-day food deprivation. In closed incubations, C and N budgets were derived from the difference between C and N uptake during feeding and subsequent C and N loss through respiration, ammonium excretion, release of particulate organic carbon and nitrogen (POC, PON). Additional feeding with krill significantly increased coral respiration (35%), excretion (131%), and POC release (67%) compared to feeding on zooplankton only. Nevertheless, the higher C and N losses were overcompensated by the threefold higher C and N uptake, indicating a high assimilation and growth efficiency for the krill plus zooplankton diet. In contrast, short food deprivation caused a substantial reduction in respiration (59%), excretion (54%), release of POC (73%) and PON (87%) compared to feeding on zooplankton, suggesting a high potential to acclimatize to food scarcity (e.g., in winter). Notwithstanding, unfed corals ‘lost’ 2% of their tissue-C and 1.2% of their tissue-N per day in terms of metabolism and released particulate organic matter (likely mucus). To balance the C (N) losses, each D. dianthus polyp has to consume around 700 (400) zooplankters per day. The capture of a single, large krill individual, however, provides enough C and N to compensate daily C and N losses and grow tissue reserves, suggesting that krill plays an important nutritional role for the fjord corals. Efficient krill and zooplankton capture, as well as dietary and metabolic flexibility, may enable D. dianthus to thrive under adverse environmental conditions in its fjord habitat; however, it is not known how combined anthropogenic warming, acidification and eutrophication jeopardize the energy balance of this important habitat-building species.

The effectiveness of protein additives based on the wastes of poultry slaughter in diets for broilers

The effectiveness of protein additives based on the wastes of poultry slaughter in diets for broilers (cross Smena-9, 35 birds per treatment, 1-38 days of age) was studied as compared to the traditional diets with fishmeal as an animal protein source. Control treatment 1 was fed diets with fishmeal (FM); in diets for treatments 2 and 3 FM was substituted by fermented feed additive (FFA) and hydrolyzed feed additive (HFA), respectively, produced by the processing of slaughter wastes (feathers, intestines, and blood). The resulting levels of crude protein were similar in all treatments. It was found that the highest growth efficiency was in treatment 2: live bodyweight at 38 days of age was higher by 6.5% in compare to control (p<0.01), average daily weight gain higher by 3.6 g/bird/day; higher digestibility of protein from FFA resulted in feed conversion ratio lower by 1.9% in compare to control. Dressing percentage in this treatment was higher by 0.8% in compare to control, percentage of high-grade carcasses higher by 5.7%; as a result the European production efficiency index (377 points) was higher by 29 points in compare to control.

Exploring spatiotemporal variation characteristics of China's industrial carbon emissions on the basis of multi-source data.

Spatiotemporal variations of industrial carbon emissions (IE) must be scientifically understood, which will be helpful to formulate reasonable emission reduction strategies. Given that spatial distribution of IE is irrelevant to space agents commonly used (such as population and nighttime light), estimation and spatialization methods for total carbon dioxide (CO2) emissions are not entirely suitable for IE. Therefore, this paper used greenhouse gases observing satellite level 4A product to estimate IE at the city level and used industrial land density to obtain the distribution of IE within the administrative districts. Sectoral emission inventories of 182 cities and a mosaic Asian anthropogenic emission inventory named MIX were used to verify the results. Then, spatiotemporal variation characteristics of China's IE were analyzed from multiple levels. Results showed that (1) the mean relative error of estimation results was 56.11%, among which 62 cities had relative error of less than 30%. Gridded IE in this paper had high consistency with MIX. (2) Cities with high IE experienced rapid growth from 2009 to 2012, followed by slower growth from 2012 to 2017. (3) Centroid of significant cold and hot spots moved to the southeast and northwest, respectively. Most cities with high annual IE growth had relatively low emission efficiency, mainly located in Inner Mongolia and Xinjiang. Aggregation of medium and high IE grids may represent high emission efficiency. Significant differences still exist between cities in IE, and sustainable development strategies should be formulated according to local conditions. Regions with high annual growth or low emission efficiency are the key to achieving IE reduction targets in future.

Investigating emergent macrophytes establishment rate and propagation towards constructed wetlands efficacy optimization

Constructed wetlands have become a widely used tool for reducing nutrient loading from agriculture drainage water running to aquatic ecosystems. To ensure a high nutrient removal efficiency, it is often suggested to use macrophytes to retain or remove nutrients via uptake and through the denitrifying biofilm. In Europe, Phragmites australis and Typha spp are the most commonly used aquatic plants in constructed wetlands (CWs) with free surface flow, and these species often form monocultures in the wetlands. In order to achieve a more diverse vegetation, there is a need to introduce more plant species. Creating a mass production of plant material reduces both handling time and the risk of depleting and disturbing vegetation in natural habitats such as streams or lakes. However, a successful and continuous production of such material during growing seasons requires knowledge of the selected species' establishment and propagation. We examined the relative growth rate (RGR) of six emergent macrophyte species collected from streams and small lakes located in Mid Jutland (Denmark), in seasonal experiments from March to October in order to determine the most efficient time period for their propagation. We found that all species had highest RGR in June, and that several species showed high growth efficiency from April to August. The results showed that it is possible to have a full production of emergent macrophytes throughout the growing season, and therefore, we suggest to propagate plants for use in constructed wetlands in order to enhance biodiversity and ecosystem functioning.

Organic Matter Composition at Ocean Station Papa Affects Its Bioavailability, Bacterioplankton Growth Efficiency and the Responding Taxa.

The bioavailability of organic matter (OM) to marine heterotrophic bacterioplankton is determined by both the chemical composition of OM and the microbial community composition. In the current study, changes in OM bioavailability were identified at Ocean Station Papa as part of the 2018 Export Processes in the Ocean from Remote Sensing (EXPORTS) field study. Removal rates of carbon (C) in controlled experiments were significantly correlated with the initial composition of total hydrolyzable amino acids, and C removal rates were high when the amino acid degradation index suggested a more labile composition. Carbon remineralization rates averaged 0.19 ± 0.08 μmol C L−1 d−1 over 6–10 days while bacterial growth efficiencies averaged 31 ± 7%. Amino acid composition and tandem mass spectrometry analysis of compound classes also revealed transformations to a more degraded OM composition during experiments. There was a log2-fold increase in the relative abundances of 16S rDNA-resolved bacterioplankton taxa in most experiments by members of the Methylophilaceae family (OM43 genus) and KI89A order. Additionally, when OM was more bioavailable, relative abundances increased by at least threefold for the classes Bacteroidetes (Flavobacteriaceae NS2b genus), Alphaproteobacteria (Rhodobacteraceae Sulfitobacter genus), and Gammaproteobacteria (Alteromonadales and Ectothiorhodospiraceae orders). Our data suggest that a diverse group of bacterioplankton was responsible for removing organic carbon and altering the OM composition to a more degraded state. Elevated community diversity, as inferred from the Shannon-Wiener H index, may have contributed to relatively high growth efficiencies by the bacterioplankton. The data presented here shed light on the interconnections between OM bioavailability and key bacterioplankton taxa for the degradation of marine OM.

Microbial Processing of Jellyfish Detritus in the Ocean.

When jellyfish blooms decay, sinking jellyfish detrital organic matter (jelly-OM), rich in proteins and characterized by a low C:N ratio, becomes a significant source of OM for marine microorganisms. Yet, the key players and the process of microbial jelly-OM degradation and the consequences for marine ecosystems remain unclear. We simulated the scenario potentially experienced by the coastal pelagic microbiome after the decay of a bloom of the cosmopolitan Aurelia aurita s.l. We show that about half of the jelly-OM is instantly available as dissolved organic matter and thus, exclusively and readily accessible to microbes. During a typical decay of an A. aurita bloom in the northern Adriatic Sea about 100 mg of jelly-OM L–1 becomes available, about 44 μmol L–1 as dissolved organic carbon (DOC), 13 μmol L–1 as total dissolved nitrogen, 11 μmol L–1 of total hydrolyzable dissolved amino acids (THDAA) and 0.6 μmol L–1 PO43–. The labile jelly-OM was degraded within 1.5 days (>98% of proteins, ∼70% of THDAA, 97% of dissolved free amino acids and the entire jelly-DOC pool) by a consortium of Pseudoalteromonas, Alteromonas, and Vibrio. These bacteria accounted for >90% of all metabolically active jelly-OM degraders, exhibiting high bacterial growth efficiencies. This implies that a major fraction of the detrital jelly-OM is rapidly incorporated into biomass by opportunistic bacteria. Microbial processing of jelly-OM resulted in the accumulation of tryptophan, dissolved combined amino acids and inorganic nutrients, with possible implications for biogeochemical cycles.

Improving the synthetic efficiency of single-wall carbon nanotube forests using a gas-analysis-designed mixed carbon feedstock

A high efficiency, mixed gas carbon feedstock was designed by gas analysis of ethylene-based single-wall carbon nanotube (SWCNT) chemical vapor deposition. Gas analysis identified acetylene and 1,3-butadiene as the primary contributors to CNT growth based on the observed correlation between the decrease in respective concentrations and the CNT growth rate. In addition, a semi-empirical chemical kinetics growth model was developed which further verified that the experimentally observed decrease of acetylene and 1,3-butadiene were due to their contribution to the synthesis reaction. Using these results, we designed a mixed carbon feedstock of acetylene and 1,3-butadiene at a ratio of 2:5 which efficiently grew high purity and selectivity SWCNTs at a high growth efficiency, four-times that of pure ethylene and two-times that of pure acetylene. The combination of acetylene and 1,3-butadiene proved synergetic due to the inherent differences in reactivity and hydrogen content through “carbon scavenging” by the hydrogen byproducts. As a result, unlike single-source carbon feedstocks, the total carbon feedstock concentration could be increased, which resulted in increasing yields without saturating the catalysts. Our results demonstrate the complementary roles of carbon feedstocks in developing high efficiency synthesis, which is important for the advancement of the synthesis of long and clean CNTs.

Adaptive trade-offs in fish energetics and physiology: insights from adaptive differentiation among juvenile salmonids

Juveniles of different salmonid species often co-exist along environmental gradients, making them a useful model for identifying dominant trade-off axes and their stability within a biological hierarchy (e.g., from individuals to populations to species). In this perspective, we use multivariate trade-offs among juvenile coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss) as a case study to explore broader-scale patterns of trait association. Multivariate ordination identified a dominant trade-off axis between high growth, consumption, and growth efficiency versus high aerobic scope and active metabolism among individual juvenile rainbow trout and three ecologically divergent rainbow trout populations. This pattern suggests a dominant trade-off between growth and active metabolism among individuals and populations, facilitated by simple developmental controls on increased energy intake (larger digestive tract, potentially more risky foraging behavior). In contrast, the adaptive trade-off differentiating species appears to have shifted to maximizing growth and consumption (rainbow trout) versus maximizing growth efficiency (coho), based on evolved differences in foraging strategy and digestive physiology. The generality of these patterns remains uncertain, but trade-offs related to growth efficiency may be an underappreciated dimension of adaptive differentiation in fishes, and their relationship to digestive strategy and active metabolism warrants further investigation.

Differential Gene Expression and Allele Frequency Changes Favour Adaptation of a Heterogeneous Yeast Population to Nitrogen-Limited Fermentations.

Alcoholic fermentation is fundamentally an adaptation process, in which the yeast Saccharomyces cerevisiae outperforms its competitors and takes over the fermentation process itself. Although wine yeast strains appear to be adapted to the stressful conditions of alcoholic fermentation, nitrogen limitations in grape must cause stuck or slow fermentations, generating significant economic losses for the wine industry. One way to discover the genetic bases that promote yeast adaptation to nitrogen-deficient environments are selection experiments, where a yeast population undergoes selection under conditions of nitrogen restriction for a number of generations, to then identify by sequencing the molecular characteristics that promote this adaptation. In this work, we carried out selection experiments in bioreactors imitating wine fermentation under nitrogen-limited fermentation conditions (SM60), using the heterogeneous SGRP-4X yeast population, to then sequence the transcriptome and the genome of the population at different time points of the selection process. The transcriptomic results showed an overexpression of genes from the NA strain (North American/YPS128), a wild, non-domesticated isolate. In addition, genome sequencing and allele frequency results allowed several QTLs to be mapped for adaptation to nitrogen-limited fermentation. Finally, we validated the ECM38 allele of NA strain as responsible for higher growth efficiency under nitrogen-limited conditions. Taken together, our results revealed a complex pattern of molecular signatures favouring adaptation of the yeast population to nitrogen-limited fermentations, including differential gene expression, allele frequency changes and loss of the mitochondrial genome. Finally, the results suggest that wild alleles from a non-domesticated isolate (NA) may have a relevant role in the adaptation to the assayed fermentation conditions, with the consequent potential of these alleles for the genetic improvement of wine yeast strains.