scholarly journals Differences in acid-base regulation of haploid and diploid life-cycle stages of Coccolithus braarudii and their consequences for the sensitivity towards ocean acidification

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Dorothee Kottmeier ◽  
Abdesslam Chrachri ◽  
Gerald Langer ◽  
Glen Wheeler ◽  
Colin Brownlee
Keyword(s):  
Life Cycle ◽  
Ocean Acidification ◽  
Environmental Conditions ◽  
Life Cycle Stage ◽  
Acid Base ◽  
Proton Channels ◽  
Voltage Gated ◽  
Life Cycle Stages ◽  
H Channels ◽  
Scanning Electron

Coccolithophores are calcifying microalgae that carry characteristic calcite platelets (coccoliths) on their surfaces. Most coccolithophore species exhibit diploid and haploid life cycle stages, each adjusted to different environmental conditions. The diploid life cycle stage of the coccolithophore C. braarudii is heavily calcifying with calcification rates that exceed the rates of photosynthesis. Haploid life-cycle stages are often weakly calcifying, generating significantly less H+ from the intracellular calcification reaction. We show how these different cellular “H+ burdens” require substantially different physiological molecular strategies to regulate intracellular pH under changing environmental conditions. Voltage-gated H+ channels (Hv) have been shown to play a role in the release of H+ in the diploid life cycle previously (Taylor et al. 2011). Combining scanning electron microscopy, electrophysiology, gene expression approaches and physiological measurements, we here show a direct link between the function of proton channels and coccolith formation of the diploid but not the haploid life-cycle stage. Our data also indicate how the different mechanisms for acid-base regulation of the diploid and haploid life-cycle stages may result in different sensitivities towards ocean acidification.

scholarly journals The Open Innovation Model of Coaching Interaction in Organisations for Sustainable Performance within the Life Cycle

2018 ◽  
Vol 10 (10) ◽  
pp. 3516 ◽  
Author(s):  
Angelina Roša (Rosha) ◽  
Natalja Lace
Keyword(s):  
Life Cycle ◽  
Open Innovation ◽  
Growth And Development ◽  
Driving Forces ◽  
Life Cycle Stage ◽  
Sustainable Growth ◽  
Business World ◽  
Sustainable Performance ◽  
Life Cycle Stages ◽  
Innovation Model

Organizations need innovation to be competitive and sustainable on their marketplace. Sustainable performance is an important precondition for growth and development. In spite of a body of literature, non-financial factors of sustainable performance remain an open issue. Coaching has gained considerable attention in the business world for its impact on sustainable performance. The current research investigates the use of coaching interaction to facilitate organizational sustainable growth and development in the context of Miller and Friesen’s five stage life-cycle model. The expert opinion survey is chosen as a central method of research. The questionnaire is developed on the literature review that is focused on the drivers for sustainable development throughout the life cycle, and the features of coaching that accelerate these driving forces. Fifteen experts took part in the survey conducted from November 2017 to January 2018. The results are estimated by considering the competence coefficient for each expert. The findings led to creation of an open innovation model, which displays relationships between the appropriate coaching forms and types and the organizational life cycle stages. The developed model enables choosing the optimal way of coaching delivery at any life cycle stage. This model is particularly valuable for the coaching support programs.

Is there a decision to make, boss? From understanding SME growth to managing employees' learning preferences

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Steven Tam ◽  
David E. Gray
Keyword(s):  
Life Cycle ◽  
High Growth ◽  
Life Cycle Stage ◽  
Learning Preferences ◽  
Best Interests ◽  
Structured Interviews ◽  
Managerial Decision ◽  
Content Type ◽  
Learning Practices ◽  
Life Cycle Stages

PurposeThis study examines employees' learning preferences in small and medium-sized enterprises (SMEs) at different life-cycle stages.Design/methodology/approachThe study has two phases. Phase I classified a sample of 30 Hong Kong SMEs into three different life-cycle stages (inception, high growth or maturity). Phase II then explored/compared their employees' learning practices in terms of importance using a mixed-method design through an online learning questionnaire followed by face-to-face semi-structured interviews.FindingsBased on a list of 32 learning practices common to SME workplaces, the study identified how SME employees perceive the importance of a learning practice. The top 5 and the bottom 5 learning practices in SMEs across life-cycle stages are presented to promote best interests for SME executives.Research limitations/implicationsWhile SME learning is highly varied, this study sheds light on some traceable context about it as an SME grows. Similar studies with additional SMEs, including SMEs in other locations, are encouraged to strengthen the findings.Practical implicationsThe findings help SME executives understand what learning practices are most important (or least important) for their employees, given the life-cycle stage of the firm. Aligning a business with employees' learning preferences in a timely fashion is a managerial decision to be made for driving organizational effectiveness.Originality/valueIt is among the first studies connecting employee learning in SMEs and organizational life cycle to address a critical but missing inquiry.

scholarly journals Identification of an antiretroviral small molecule that appears to be a host-targeting inhibitor of HIV-1 assembly.

2020 ◽  
Author(s):  
Jonathan C. Reed ◽  
Dennis Solas ◽  
Anatoliy Kitaygorodskyy ◽  
Beverly Freeman ◽  
Dylan T. B. Ressler ◽  
...  
Keyword(s):  
Life Cycle ◽  
Virus Production ◽  
Life Cycle Stage ◽  
Multidrug Resistant ◽  
Capsid Assembly ◽  
Resistance Mutations ◽  
Life Cycle Stages ◽  
Human T Cell ◽  
Gag Assembly ◽  
Hiv 1

Given the projected increase in multidrug resistant HIV-1, there is an urgent need for development of antiretrovirals that act on virus life-cycle stages not targeted by drugs currently in use. Host-targeting compounds are of particular interest because they can offer a high barrier to resistance. Here we report identification of two related small molecules that inhibit HIV-1 late events, an HIV-1 life cycle stage for which potent and specific inhibitors are lacking. This chemotype was discovered using cell-free protein synthesis and assembly systems that recapitulate intracellular host-catalyzed viral capsid assembly pathways. These compounds inhibit replication of HIV-1 in human T cell lines and PBMCs and are effective against a primary isolate. They reduce virus production, likely by inhibiting a post-translational step in HIV-1 Gag assembly. Notably, the compound colocalizes with HIV-1 Gag in situ; however, unexpectedly, selection experiments failed to identify compound-specific resistance mutations in gag or pol, even though known resistance mutations developed upon parallel nelfinavir selection. Thus, we hypothesized that instead of binding to Gag directly, these compounds localize to assembly intermediates, the intracellular multiprotein complexes containing Gag and host factors that form during immature HIV-1 capsid assembly. Indeed, imaging of infected cells shows compound colocalized with two host enzymes found in assembly intermediates, ABCE1 and DDX6, but not two host proteins found in other complexes. While the exact target and mechanism of action of this chemotype remain to be determined, these findings suggest that these compounds represent first-in-class, host-targeting inhibitors of intracellular events in HIV-1 assembly. IMPORTANCE The success of antiretroviral treatment for HIV-1 is at risk of being undermined by the growing problem of drug resistance. Thus, there is a need to identify antiretrovirals that act on viral life cycle stages not targeted by drugs in use, such as the events of HIV-1 Gag assembly. To address this gap, we developed a compound screen that recapitulates the intracellular events of HIV-1 assembly, including viral-host interactions that promote assembly. This effort led to identification of a new chemotype that inhibits HIV-1 replication at nanomolar concentrations, likely by acting on assembly. This compound colocalized with Gag and two host enzymes that facilitate capsid assembly. However, resistance selection did not result in compound-specific mutations in gag, suggesting that the chemotype does not directly target Gag. We hypothesize that this chemotype represents a first-in-class inhibitor of virus production that acts by targeting a viral-host complex important for HIV-1 Gag assembly.

Surface Characteristics of Observed Cold Pools

2008 ◽  
Vol 136 (12) ◽  
pp. 4839-4849 ◽  
Author(s):  
Nicholas A. Engerer ◽  
David J. Stensrud ◽  
Michael C. Coniglio
Keyword(s):  
Life Cycle ◽  
Potential Temperature ◽  
Surface Characteristics ◽  
Life Cycle Stage ◽  
Cold Pool ◽  
Convective System ◽  
Cold Pools ◽  
Equivalent Potential ◽  
Life Cycle Stages ◽  
The Mean

Abstract Cold pools are a key element in the organization of precipitating convective systems, yet knowledge of their typical surface characteristics is largely anecdotal. To help to alleviate this situation, cold pools from 39 mesoscale convective system (MCS) events are sampled using Oklahoma Mesonet surface observations. In total, 1389 time series of surface observations are used to determine typical rises in surface pressure and decreases in temperature, potential temperature, and equivalent potential temperature associated with the cold pool, and the maximum wind speeds in the cold pool. The data are separated into one of four convective system life cycle stages: first storms, MCS initiation, mature MCS, and MCS dissipation. Results indicate that the mean surface pressure rises associated with cold pools increase from 3.2 hPa for the first storms’ life cycle stage to 4.5 hPa for the mature MCS stage before dropping to 3.3 hPa for the dissipation stage. In contrast, the mean temperature (potential temperature) deficits associated with cold pools decrease from 9.5 (9.8) to 5.4 K (5.6 K) from the first storms to the dissipation stage, with a decrease of approximately 1 K associated with each advance in the life cycle stage. However, the daytime and early evening observations show mean temperature deficits over 11 K. A comparison of these observed cold pool characteristics with results from idealized numerical simulations of MCSs suggests that observed cold pools likely are stronger than those found in model simulations, particularly when ice processes are neglected in the microphysics parameterization. The mean deficits in equivalent potential temperature also decrease with the MCS life cycle stage, starting at 21.6 K for first storms and dropping to 13.9 K for dissipation. Mean wind gusts are above 15 m s−1 for all life cycle stages. These results should help numerical modelers to determine whether the cold pools in high-resolution models are in reasonable agreement with the observed characteristics found herein. Thunderstorm simulations and forecasts with thin model layers near the surface are also needed to obtain better representations of cold pool surface characteristics that can be compared with observations.

scholarly journals The genetic covariance between life cycle stages separated by metamorphosis

2014 ◽  
Vol 281 (1788) ◽  
pp. 20141091 ◽  
Author(s):  
J. David Aguirre ◽  
Mark W. Blows ◽  
Dustin J. Marshall
Keyword(s):  
Life Cycle ◽  
Life Cycle Stage ◽  
Evolutionary Change ◽  
Phenotypic Evolution ◽  
Genetic Associations ◽  
Embryo Viability ◽  
Genetic Covariance ◽  
Life Cycle Stages ◽  
Target Matrix ◽  
Before And After

Metamorphosis is common in animals, yet the genetic associations between life cycle stages are poorly understood. Given the radical changes that occur at metamorphosis, selection may differ before and after metamorphosis, and the extent that genetic associations between pre- and post-metamorphic traits constrain evolutionary change is a subject of considerable interest. In some instances, metamorphosis may allow the genetic decoupling of life cycle stages, whereas in others, metamorphosis could allow complementary responses to selection across the life cycle. Using a diallel breeding design, we measured viability at four ontogenetic stages (embryo, larval, juvenile and adult viability), in the ascidian Ciona intestinalis and examined the orientation of additive genetic variation with respect to the metamorphic boundary. We found support for one eigenvector of G ( g obs max ), which contrasted larval viability against embryo viability and juvenile viability. Target matrix rotation confirmed that while g obs max shows genetic associations can extend beyond metamorphosis, there is still considerable scope for decoupled phenotypic evolution. Therefore, although genetic associations across metamorphosis could limit that range of phenotypes that are attainable, traits on either side of the metamorphic boundary are capable of some independent evolutionary change in response to the divergent conditions encountered during each life cycle stage.

Developmental aspects of uridine addition within mitochondrial transcripts of Trypanosoma brucei

1988 ◽  
Vol 8 (3) ◽  
pp. 1259-1265
Author(s):  
J E Feagin ◽  
K Stuart
Keyword(s):  
Life Cycle ◽  
Cytochrome Oxidase ◽  
Trypanosoma Brucei ◽  
Cytochrome B ◽  
Respiratory System ◽  
Life Cycle Stage ◽  
Stage Specificity ◽  
Life Cycle Stages ◽  
Mitochondrial Transcripts ◽  
Cytochrome Oxidase Ii

The mitochondrial respiratory system is absent in slender bloodstream forms of Trypanosoma brucei, incomplete in stumpy bloodstream forms, and complete in procyclic (insect) forms. The steady-state abundance of transcripts of some mitochondrially encoded components of the respiratory system correlates with its differential expression in different life cycle stages. Recently, it was reported that uridines which are not encoded in the genome are added to cytochrome b and cytochrome oxidase II transcripts. We now report that the (U)+ transcripts of both genes are found in procyclic forms and to some degree in stumpy forms but are absent in slender forms. The uridine additions to cytochrome oxidase II correct a frameshift in the gene and presumably allow production of a full-length protein, whereas those added to cytochrome b create an in-frame AUG which extends the N terminus of the predicted protein by 20 amino acids. The stage specificity of uridine additions to these transcripts thus reflects the life cycle stage during which the protein products would be used. Transcripts of MURF2, a gene of unknown function, have additional uridines in both slender and procyclic forms which create two in-frame AUGs. MURF2 transcripts additionally differ from the DNA sequence in ways which cannot be explained by uridine addition alone, implying that other processes alter these transcripts.

Family life cycle and preferences for a mega-sporting event package: The case of the 2018 PyeongChang Winter Olympic Games

2020 ◽  
pp. 135481662090778
Author(s):  
Hyesun Kim ◽  
Jooa Baek ◽  
Yeongbae Choe
Keyword(s):  
Life Cycle ◽  
Family Life ◽  
Life Cycle Stage ◽  
Family Life Cycle ◽  
Sporting Events ◽  
Safety Issues ◽  
Travel Costs ◽  
Sporting Event ◽  
Life Cycle Stages ◽  
Winter Olympic Games

Mega-sporting events often contribute to both financial and nonfinancial aspects of a destination. Nonetheless, several problematic issues (e.g. risk/safety issues, high travel costs, and online broadcasting) require a hosting destination focusing more on marketing and promotion strategies to boost event attendance. As such, this study aims to understand the optimal bundling package strategy for a mega-sporting event by investigating the effect of customers’ life cycle stage on their preferences in purchasing an event-related package. Several event package features used in this study are important determinants of mega-sporting event participation. More important, respondents in different family life cycle stages showed different levels of sensitivity to each package attribute, thereby constructing different preferences. The result of this study would be useful information for designing more attractive mega-sporting event packages and/or target marketing strategies focusing on different life stages.

Brachylaima cribbi(Digenea: Brachylaimidae): scanning electron microscopical observations of the life-cycle stages

2002 ◽  
Vol 76 (3) ◽  
pp. 207-215 ◽  
Author(s):  
A.R. Butcher ◽  
J.K. Brealey ◽  
D.I. Grove ◽  
R.B. Dymock
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Life Cycle ◽  
Adult Worm ◽  
Genital Pore ◽  
Land Snails ◽  
Intermediate Hosts ◽  
Mature Adult ◽  
Life Cycle Stages ◽  
Scanning Electron

AbstractBrachylaima cribbiis a recently described species of terrestrial trematode that infects mammals and birds with helicid land snails as its first and second intermediate hosts. The adult worm is 2.5–6.0 mm long by 0.5–0.8 mm wide being a long slender cylindrical worm with oral and ventral suckers in the anterior quarter and genital pore in the posterior quarter. Scanning electron microscopy shows that there is a dense covering of tegumental spines at the anterior end which diminishes towards the posterior extremities of the worm. Development of spines was observed in juvenile and mature adult worms. In young worms 1–3 weeks post infection (wpi) spines appear as buds with a serrated edge each having 1–4 spikes per spine. As the worm ages the spines broaden and by 5 wpi the number of spikes per spine increases to an average of 8.1. The serial development of oral sucker papillae in the cercaria, metacercaria and adult worm was observed with the finding of an elongated papilla with a bifurcated tip on the cercaria becoming a shorter and thicker elongated papilla with a large central stoma on the metacercaria. In the adult worm, this papilla becomes dome-shaped with a small central stoma. For some of these papillae a cilium could be seen extended from the central stoma. Other life-cycle stages illustrated were the hatched egg with an extruded egg membrane minus an operculum and a portion of the branched sporocyst dissected from the digestive gland of the land snailTheba pisanashowing a terminal birth pore. Scanning electron microscopy morphological features of the adult worm observed for the first time in aBrachylaimawere the unarmed cirrus extended from the genital pore with released sperm present and the Laurer's canal opening visible in tegumental folds on the dorsal surface approximately 300 μm posterior to the genital pore.

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