scholarly journals Immobilization of active ammonia-oxidizing archaea in hydrogel beads

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Matthieu Landreau ◽  
HeeJun You ◽  
David A. Stahl ◽  
Mari K. H. Winkler
Keyword(s):  
Diffusion Coefficients ◽  
Ammonia Oxidation ◽  
Slow Growth ◽  
Poly Vinyl Alcohol ◽  
Lag Phase ◽  
Slow Growth Rate ◽  
Hydrogel Beads ◽  
Ammonia Oxidizing Archaea ◽  
Batch Systems ◽  
Over Time

AbstractAmmonia-oxidizing archaea (AOA) are major players in the nitrogen cycle but their cultivation represents a major challenge due to their slow growth rate and limited tendency to form biofilms. In this study, AOA was embedded in small (~2.5 mm) and large (~4.7 mm) poly(vinyl alcohol) (PVA)—sodium alginate (SA) hydrogel beads cross-linked with four agents (calcium, barium, light, or sulfate) to compare the differences in activity, the diffusivity of nitrogen species (NH4+, NO2−, and NO3−), and polymer leakage in batch systems over time. Sulfate-bound PVA-SA beads were the most stable, releasing the lowest amount of polymer without shrinking. Diffusion coefficients were found to be 2 to 3 times higher in hydrogels than in granules, with ammonium diffusivity being ca. 35% greater than nitrite and nitrate. Despite a longer lag phase in small beads, embedded AOA sustained a high per volume rate of ammonia oxidation compatible with applications in research and wastewater treatment.

scholarly journals An empirical model for the spread and reduction of the CoVid19 pandemic

2020 ◽  
Vol 38 (2) ◽  
Author(s):  
Joaquim Clara-Rahola
Keyword(s):  
Growth Rate ◽  
Infection Rate ◽  
Master Curve ◽  
Slow Growth ◽  
Initial Study ◽  
Infection Rates ◽  
Soft Or ◽  
Crossover Point ◽  
Slow Growth Rate ◽  
Over Time

This document depicts an empirical approach to the dynamics of diagnosed CoVid19 infections at outbreak scenarios. Here we study empirical daily diagnosed infections and by performing an initial study based on basic models of infection spreads, we find two distinct exponential regimes in which the CoVid19 displays an infection growth rate. Here, measures such as household lockdown are critical in order to lower the infection rate. As a result, a crossover point between fast and slow infection rates is found one week after lockdown, which is turn is the average CoVid19’s incubation period. After this crossover point, and following the slow growth rate, infections reach a maximum after which the infection rate starts to decrease. A possible peak can be found latter to this lockdown critical point, due to a number of households being infected by subjects already sick from the spread periods. However, such peak is a singularity as due to lockdown the diagnosed infections keep decreasing exponentially. Note that this profile, which we have denoted as Whuan Quality-Curve (Or Whuan Q-Curve) is characteristic to the evolution of CoVid19 in china as infected countries such as Spain or Italy still are at early stages of the Whuan Q-Curve. However, both countries display such profile up to date. Furthermore, our analysis and the proposal of the Q-Curve as a master curve to consider in each CoVid19 outbreak, allows a prediction of outbreak periods, i.e. free spread or lockdown periods, as well as diagnosed cases over time, provided that an initial data analysis is performed at the beginning of the outbreak. We also study the case of South Korea, where early measures where implemented against CoVid19. Finally, data indicates that a soft or hard lockdown result in the same outcome when fighting against CoVid19.

scholarly journals Soil ammonia-oxidizing archaea in a paddy field with different irrigation and fertilization managements

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Limin Wang ◽  
Dongfeng Huang
Keyword(s):  
Ammonia Oxidation ◽  
Chemical Properties ◽  
Paddy Soils ◽  
Soil Nitrification ◽  
Treated Soil ◽  
Ammonia Oxidizing Archaea ◽  
Rice Yields ◽  
Traditional Irrigation ◽  
Almost All ◽  
And Function

AbstractBecause ammonia-oxidizing archaea (AOA) are ubiquitous and highly abundant in almost all terrestrial soils, they play an important role in soil nitrification. However, the changes in the structure and function of AOA communities and their edaphic drivers in paddy soils under different fertilization and irrigation regimes remain unclear. In this study, we investigated AOA abundance, diversity and activity in acid paddy soils by a field experiment. Results indicated that the highest potential ammonia oxidation (PAO) (0.011 μg NO 2 -  –N g-1 d.w.day-1) was found in T2 (optimal irrigation and fertilization)—treated soils, whereas the lowest PAO (0.004 μg NO 2 -  –N g-1 d.w.day-1) in T0 (traditional irrigation)- treated soils. Compared with the T0—treated soil, the T2 treatment significantly (P < 0.05) increased AOA abundances. Furthermore, the abundance of AOA was significantly (P < 0.01) positively correlated with pH, soil organic carbon (SOC), and PAO. Meanwhile, pH and SOC content were significantly (P < 0.05) higher in the T2—treated soil than those in the T1 (traditional irrigation and fertilization)- treated soil. In addition, these two edaphic factors further influenced the AOA community composition. The AOA phylum Crenarchaeota was mainly found in the T2—treated soils. Phylogenetic analysis revealed that most of the identified OTUs of AOA were mainly affiliated with Crenarchaeota. Furthermore, the T2 treatment had higher rice yield than the T0 and T1 treatments. Together, our findings confirm that T2 might ameliorate soil chemical properties, regulate the AOA community structure, increase the AOA abundance, enhance PAO and consequently maintain rice yields in the present study.

Time-Energy Budgets During Reproduction and the Evolution of Single Parenting in the Superb Lyrebird

1986 ◽  
Vol 34 (3) ◽  
pp. 351 ◽  
Author(s):  
A Lill
Keyword(s):  
Growth Rate ◽  
Brood Size ◽  
Slow Growth ◽  
Bird Species ◽  
Egg Laying ◽  
Energy Budgets ◽  
Brood Care ◽  
Single Parenting ◽  
Slow Growth Rate ◽  
Small Brood

Estimated expenditures on brood-care by unassisted female superb lyrebirds, obtained through time-energy budgeting, were compared with published values for other bird species. With the exception of nestbuilding, estimated daily expenditures were relatively low, due mainly to the small brood size and low level of parental attentiveness. It is suggested that the traits which reduce daily brood-care expenditures, particularly the small brood size and extremely slow growth rate, may have evolved as adaptations which enabled deserted females operating close to maximal capacity to cope with single-parenting. Male parental involvement could probably increase the growth rate of the young, but not brood size; moreover, egg- laying was sufficiently asynchronous to afford multiple mating opportunities to parentally emancipated males. However, the slow growth rate of the young results in relatively large overall brood-care expenditures for females. Investments by males of up to 50% of daylight hours and 45% of BMR on singing at the height of the mating season were comparable with those of partially emancipated, polygynous males of other species. They probably reflect the high level of competition to control good display areas and to advertise status and quality to widely spaced females.

scholarly journals Effect of physiological age of stem and IBA treatment on rooting of branch cuttings of Taxus baccata L.

1970 ◽  
pp. 01-07
Author(s):  
Saumitro Das ◽  
L.K. Jha
Keyword(s):  
Growth Rate ◽  
Large Scale ◽  
Slow Growth ◽  
Physiological Age ◽  
Taxus Baccata ◽  
Practical Solution ◽  
Slow Growth Rate ◽  
Rooting Response ◽  
Himalayan Yew ◽  
Rooting Capacity

The natural population of Taxus baccata L. (Himalayan Yew) throughout the Indian Himalayan Region is greatly reduced due to its extensive and reckless exploitation for “Taxol” an anticancer drug. The effects of overexploitation are exacerbated by the species poor regeneration process, slow growth rate and prolonged seed dormancy. Therefore vegetative propagation by branch cuttings seems to be only practical solution for its large scale multiplication. A study was conducted on six candidate trees (CTs) to examine the effect genotype, physiological age of stem, IBA treatment on rooting of Taxus baccata cuttings. Results revealed that rooting behaviour of cuttings was significantly affected by all the factors under study. Among the six CTs studied, CT 2 (from BSI, Shillong) had given the highest rooting response (46.28%). The juvenile cuttings have the higher rooting capacity; however the callusing was more prominent in mature cutting. The influence of IBA treatment was also significant for rooting where 1000 was most effective for stimulating rooting juvenile cuttings and 2000 ppm in mature cuttings.

scholarly journals The mitochondrial AAA protease FTSH3 regulates Complex I abundance by promoting its disassembly

2021 ◽  
Author(s):  
Aneta Ivanova ◽  
Abi S Ghifari ◽  
Oliver Berkowitz ◽  
James Whelan ◽  
Monika W Murcha
Keyword(s):  
Complex I ◽  
Nadh Dehydrogenase ◽  
Slow Growth ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Forward Genetic Screen ◽  
Slow Growth Rate ◽  
Partial Restoration ◽  
Screen Approach

Abstract ATP is generated in mitochondria by oxidative phosphorylation. Complex I (NADH:ubiquinone oxidoreductase or NADH dehydrogenase) is the first multisubunit protein complex of this pathway, oxidising NADH and transferring electrons to the ubiquinone pool. Typically Complex I mutants display a slow growth rate compared to wild-type plants. Here, using a forward genetic screen approach for restored growth of a Complex I mutant, we have identified the mitochondrial ATP dependent metalloprotease, Filamentous Temperature Sensitive H 3 (FTSH3), as a factor that is required for the disassembly of Complex I. An ethyl methanesulfonate-induced mutation in FTSH3, named rmb1 (restoration of mitochondrial biogenesis 1), restored Complex I abundance and plant growth. Complementation could be achieved with FTSH3 lacking proteolytic activity, suggesting the unfoldase function of FTSH3 has a role in Complex I disassembly. The introduction of the rmb1 to an additional, independent, and extensively characterised Complex I mutant, ndufs4, resulted in similar increases to Complex I abundance and a partial restoration of growth. These results show that disassembly or degradation of Complex I plays a role in determining its steady-state abundance and thus turnover may vary under different conditions.

Ustilago bullata. [Descriptions of Fungi and Bacteria].

1981 ◽  
Author(s):  
J. E. M. Mordue
Keyword(s):  
Geographical Distribution ◽  
Latent Infection ◽  
Slow Growth ◽  
Poor Survival ◽  
Head Smut ◽  
Slow Growth Rate ◽  
North And South America ◽  
North And South ◽  
Leaf Distortion ◽  
Infection Hypha

Abstract A description is provided for Ustilago bullata. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Agropyron, Bromus, Brachypodium, Elymus, Festuca, Hordeum, Sitanion. DISEASE: Causes head smut of grasses particularly species of Bromus and Agropyron. Sori develop at the base of spikelets and usually involve the ovary but glumes are usually unaffected, phyllody of floral parts also occurs. Latent infection with very reduced sori production can also occur. Infected seedlings show stunting and poor survival, older plants show slow growth rate and leaf distortion has been observed (56, 265). GEOGRAPHICAL DISTRIBUTION: Europe, North and South America, W. Asia (USSR, Poland, Iraq), India, Kenya, Australia, New Zealand. TRANSMISSION: Teliospores are released from the inflorescence sori to contaminate soil and seed. Teliospores have remained viable (in artificial storage) for 12 years. Germination results in the production of a metabasidium and sporidia, plasmogamy then produces a dikaryotic infection hypha. Seedlings and older shoots become infected, the former producing completely infected plants, but the latter producing separately diseased tillers (see Falloon, 1979).

Embryonic oxygen consumption and growth of Laysan and black-footed albatross

1982 ◽  
Vol 242 (1) ◽  
pp. R121-R128 ◽  
Author(s):  
T. N. Pettit ◽  
G. S. Grant ◽  
G. C. Whittow ◽  
H. Rahn ◽  
C. V. Paganelli
Keyword(s):  
Oxygen Consumption ◽  
Slow Growth ◽  
Egg Mass ◽  
Low Oxygen ◽  
O2 Uptake ◽  
Prolonged Incubation ◽  
Slow Growth Rate ◽  
Air Space ◽  
Embryonic Metabolism ◽  
Pulmonary Respiration

The constraints placed on diffusive gas exchange by the eggshell and the adaptive features of embryonic respiration and metabolism in large Laysan and black-footed albatross eggs (300 g) during prolonged incubation (65 days) were examined in naturally incubated eggs on Sand Island, Midway, in the Northwestern Hawaiian Islands. A low eggshell gas conductance and slow growth rate were associated with a relatively low oxygen consumption (MO2) throughout incubation. Just prior to internal pipping (IP) of the inner shell membrane and penetration of the air space, the MO2 (pre-IP MO2) was approximately 1,250 ml O2 (STPD).day-1 for both species, resulting in air cell O2 and CO2 tensions of 106 and 40 Torr, respectively. During the 4- to 5-day pipping-to-hatching interval, O2 uptake increases rapidly as pulmonary respiration is initiated. Hatchling O2 consumption averaged 3,700 ml O2 (STPD).day-1 or about three times the pre-IP MO2. Data support the hypothesis that embryonic metabolism among Procellariiformes is related to the extent to which the incubation period deviates from the expected value based on initial egg mass.

scholarly journals Measurements of nitrite production in and around the primary nitrite maximum in the central California Current

2013 ◽  
Vol 10 (11) ◽  
pp. 7395-7410 ◽  
Author(s):  
A. E. Santoro ◽  
C. M. Sakamoto ◽  
J. M. Smith ◽  
J. N. Plant ◽  
A. L. Gehman ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
California Current ◽  
Euphotic Zone ◽  
Ammonia Oxidizing Bacteria ◽  
Central California ◽  
Oxidation Rates ◽  
Ammonia Oxidizing Archaea ◽  
Nitrite Production ◽  
Nh3 Oxidation

Abstract. Nitrite (NO2−) is a substrate for both oxidative and reductive microbial metabolism. NO2− accumulates at the base of the euphotic zone in oxygenated, stratified open-ocean water columns, forming a feature known as the primary nitrite maximum (PNM). Potential pathways of NO2− production include the oxidation of ammonia (NH3) by ammonia-oxidizing bacteria and archaea as well as assimilatory nitrate (NO3−) reduction by phytoplankton and heterotrophic bacteria. Measurements of NH3 oxidation and NO3− reduction to NO2− were conducted at two stations in the central California Current in the eastern North Pacific to determine the relative contributions of these processes to NO2− production in the PNM. Sensitive (< 10 nmol L−1), precise measurements of [NH4+] and [NO2−] indicated a persistent NH4+ maximum overlying the PNM at every station, with concentrations as high as 1.5 μmol L−1. Within and just below the PNM, NH3 oxidation was the dominant NO2− producing process, with rates of NH3 oxidation to NO2− of up to 31 nmol L−1 d−1, coinciding with high abundances of ammonia-oxidizing archaea. Though little NO2− production from NO3− was detected, potentially nitrate-reducing phytoplankton (photosynthetic picoeukaryotes, Synechococcus, and Prochlorococcus) were present at the depth of the PNM. Rates of NO2− production from NO3− were highest within the upper mixed layer (4.6 nmol L−1 d−1) but were either below detection limits or 10 times lower than NH3 oxidation rates around the PNM. One-dimensional modeling of water column NO2− production agreed with production determined from 15N bottle incubations within the PNM, but a modeled net biological sink for NO2− just below the PNM was not captured in the incubations. Residence time estimates of NO2− within the PNM ranged from 18 to 470 days at the mesotrophic station and was 40 days at the oligotrophic station. Our results suggest the PNM is a dynamic, rather than relict, feature with a source term dominated by ammonia oxidation.

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