In situ observations of Akashiwo sanguinea (Dinophyceae) displaying life cycle stages during blooms in a subtropical estuary

Accurate prediction of life cycle of cyclone is very critical to the disaster management practices. Since the cyclones originate over the oceans where in situ observations are limited, we have to resort to the remote sensing techniques. Both optical and microwave sensors help studying the cyclones. While scatterometer provide wind vectors, altimeters can give only wind speed. In this paper we present how altimeter measurements can supplement the scatterometer observations in determining the radius of maximum winds (RMW). Sustained maximum winds, indicator for the intensity of the cyclone, are within the eye wall of a cyclone at a distance of RMW. This parameter is also useful in predicting right time of the storm surge. In this paper we used the wind speed estimations from AltiKa, an altimeter operating at Ka band.

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Microtubule polyglutamylation is important for regulating cytoskeletal architecture and motility in Trypanosoma brucei

Journal of Cell Science ◽

10.1242/jcs.248047 ◽

2020 ◽

Vol 133 (18) ◽

pp. jcs248047 ◽

Cited By ~ 2

Author(s):

Jana Jentzsch ◽

Adal Sabri ◽

Konstantin Speckner ◽

Gertrud Lallinger-Kube ◽

Matthias Weiss ◽

...

Keyword(s):

Cell Cycle ◽

Life Cycle ◽

Trypanosoma Brucei ◽

Dynamic Behaviour ◽

Cell Movement ◽

Post Translational Modifications ◽

Life Cycle Stages ◽

Associated Proteins ◽

Flagellar Axoneme

ABSTRACTThe shape of kinetoplastids, such as Trypanosoma brucei, is precisely defined during the stages of the life cycle and governed by a stable subpellicular microtubule cytoskeleton. During the cell cycle and transitions between life cycle stages, this stability has to transiently give way to a dynamic behaviour to enable cell division and morphological rearrangements. How these opposing requirements of the cytoskeleton are regulated is poorly understood. Two possible levels of regulation are activities of cytoskeleton-associated proteins and microtubule post-translational modifications (PTMs). Here, we investigate the functions of two putative tubulin polyglutamylases in T. brucei, TTLL6A and TTLL12B. Depletion of both proteins leads to a reduction in tubulin polyglutamylation in situ and is associated with disintegration of the posterior cell pole, loss of the microtubule plus-end-binding protein EB1 and alterations of microtubule dynamics. We also observe a reduced polyglutamylation of the flagellar axoneme. Quantitative motility analysis reveals that the PTM imbalance correlates with a transition from directional to diffusive cell movement. These data show that microtubule polyglutamylation has an important role in regulating cytoskeletal architecture and motility in the parasite T. brucei.This article has an associated First Person interview with the first author of the paper.

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Intron-containing β-tubulin transcripts in Cryptosporidium parvum cultured in vitro

Microbiology ◽

10.1099/mic.0.26897-0 ◽

2004 ◽

Vol 150 (5) ◽

pp. 1191-1195 ◽

Cited By ~ 11

Author(s):

Xiaomin Cai ◽

Cheryl A. Lancto ◽

Mitchell S. Abrahamsen ◽

Guan Zhu

Keyword(s):

Life Cycle ◽

Cryptosporidium Parvum ◽

Late Life ◽

Host Cells ◽

Intron Splicing ◽

Transcript Processing ◽

Life Cycle Stages ◽

Tubulin Mrna

The genome of Cryptosporidium parvum contains a relatively small number of introns, which includes the β-tubulin gene with only a single intron. Recently, it was observed that the intron was not removed from some of the β-tubulin transcripts in the late life cycle stages cultured in vitro. Although normally spliced β-tubulin mRNA was detected in all parasite intracellular stages by RT-PCR (e.g. HCT-8 or Caco-2 cells infected with C. parvum for 12–72 h), at 48–72 h post-infection unprocessed β-tubulin transcripts containing intact introns started to appear in parasite mRNA within infected host cells. The intron-containing transcripts could be detected by fluorescence in situ hybridization (FISH) using an intron-specific probe. The intron-containing β-tubulin transcripts appeared unique to the in vitro-cultured C. parvum, since they were not detected in parasite-infected calves at 72 h. As yet, it is unclear whether the late life cycle stages of C. parvum are partially deficient in intron-splicing or the intron-splicing processes have merely slowed, both of which would allow the detection of intron-containing transcripts. Another possible explanation is that the decay in transcript processing might simply be due to the onset of parasite death. Nonetheless, the appearance of intron-containing transcripts coincides with the arrest of C. parvum development in vitro. This unusual observation prompts speculation that the abnormal intron-splicing of β-tubulin transcripts may be one of the factors preventing complete development of this parasite in vitro. Furthermore, the presence of both processed and unprocessed introns in β-tubulin transcripts in vitro may provide a venue for studying overall mechanisms for intron-splicing in this parasite.

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Light-Dependent Transcriptional Regulation of Genes of Biogeochemical Interest in the Diploid and Haploid Life Cycle Stages of Emiliania huxleyi

Applied and Environmental Microbiology ◽

10.1128/aem.02737-08 ◽

2009 ◽

Vol 75 (10) ◽

pp. 3366-3369 ◽

Cited By ~ 15

Author(s):

Sophie Richier ◽

Marie-Emmanuelle Kerros ◽

Colomban de Vargas ◽

Liti Haramaty ◽

Paul G. Falkowski ◽

...

Keyword(s):

Transcriptional Regulation ◽

Life Cycle ◽

Emiliania Huxleyi ◽

Life Stages ◽

Dark Cycle ◽

Expression Of Genes ◽

Life Cycle Stages

ABSTRACT The expression of genes of biogeochemical interest in calcifying and noncalcifying life stages of the coccolithophore Emiliania huxleyi was investigated. Transcripts potentially involved in calcification were tested through a light-dark cycle. These transcripts were more abundant in calcifying cells and were upregulated in the light. Their application as potential candidates for in situ biogeochemical proxies is also suggested.

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An Investigation of the Goshen County, Wyoming, Tornadic Supercell of 5 June 2009 Using EnKF Assimilation of Mobile Mesonet and Radar Observations Collected during VORTEX2. Part II: Mesocyclone-Scale Processes Affecting Tornado Formation, Maintenance, and Decay

Monthly Weather Review ◽

10.1175/mwr-d-15-0411.1 ◽

2016 ◽

Vol 144 (9) ◽

pp. 3441-3463 ◽

Cited By ~ 12

Author(s):

James Marquis ◽

Yvette Richardson ◽

Paul Markowski ◽

Joshua Wurman ◽

Karen Kosiba ◽

...

Keyword(s):

Life Cycle ◽

Ensemble Kalman Filter ◽

Vertical Structure ◽

Spatial Scales ◽

Near Surface ◽

Low Level ◽

Structure Changes ◽

In Situ Observations ◽

Negatively Buoyant

Storm-scale and mesocyclone-scale processes occurring contemporaneously with a tornado in the Goshen County, Wyoming, supercell observed on 5 June 2009 during the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) are examined using ensemble analyses produced by assimilating mobile radar and in situ observations into a high-resolution convection-resolving model. This paper focuses on understanding the evolution of the vertical structure of the storm, the outflow buoyancy, and processes affecting the vertical vorticity and circulation within the mesocyclone that correspond to changes in observed tornado intensity. Tornadogenesis occurs when the low-level mesocyclone is least negatively buoyant relative to the environment, possesses its largest circulation, and is collocated with the largest azimuthally averaged convergence during the analysis period. The average buoyancy, circulation, and convergence within the near-surface mesocyclone (on spatial scales resolved by the model) all decrease as the tornado intensifies and matures. The tornado and its parent low-level mesocyclone both dissipate surrounded by a weakening rear-flank downdraft. The decreasing buoyancy of parcels within the low-level mesocyclone may partly be responsible for the weakening of the updraft surrounding the tornado and decoupling of the mid- and low-level circulation. Although the supply of horizontal vorticity generated in the forward flank of the storm increases throughout the life cycle of the tornado, it is presumably less easily tilted and stretched on the mesocyclone-scale during tornado maturity owing to the disruption of the low-level updraft/downdraft structure. Changes in radar-measured tornado intensity lag those of ensemble Kalman filter (EnKF) mesocyclone vorticity and circulation.

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Harmful Algal Bloom-Forming Organism Responds to Nutrient Stress Distinctly From Model Phytoplankton

10.1101/2021.02.08.430350 ◽

2021 ◽

Author(s):

Craig McLean ◽

Sheean T. Haley ◽

Gretchen J. Swarr ◽

Melissa C. Kido Soule ◽

Sonya T. Dyhrman ◽

...

Keyword(s):

Algal Bloom ◽

Phytoplankton Bloom ◽

Harmful Algal Bloom ◽

Resource Limitation ◽

Metabolic Responses ◽

List Type ◽

P Availability ◽

Trade Offs ◽

Dynamics Models

SummaryResources such as nitrogen (N) and phosphorus (P) play an important role in primary production and constraining phytoplankton bloom dynamics. Models to predict bloom dynamics require mechanistic knowledge of algal metabolic shifts in response to resource limitation. For well-studied model phytoplankton like diatoms, this information is plentiful. However, for less-studied groups such as the raphidophytes, there remain significant gaps in understanding metabolic changes associated with nutrient limitation.Using a novel combination of metabolomics and transcriptomics, we examined how the harmful algal bloom-forming raphidophyte Heterosigma akashiwo shifts its metabolism under N- and P-stress. We chose H. akashiwo because of its ubiquity within estuarine environments worldwide, where bloom dynamics are influenced by N and P availability.Our results show that each stress phenotype is distinct in both the allocation of carbon and the recycling of macromolecules. Further, we identified biomarkers of N- and P-stress that may be applied in situ to help modelers and stakeholders manage, predict, and prevent future blooms.These findings provide a mechanistic foundation to model the metabolic traits and trade-offs associated with N- and P-stress in H. akashiwo, and evaluate the extent to which these metabolic responses can be inferred in other phytoplankton groups.

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