scholarly journals Analysis of Encystment, Excystment, and Cyst Structure in Freshwater Eutardigrade Thulinius ruffoi (Tardigrada, Isohypsibioidea: Doryphoribiidae)

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 62 ◽  
Author(s):  
Kamil Janelt ◽  
Izabela Poprawa
Keyword(s):  
Phenotypic Plasticity ◽  
Cyst Wall ◽  
Environmental Conditions ◽  
Morphological Changes ◽  
Adaptive Strategy ◽  
Cyst Formation ◽  
Feeding Apparatus ◽  
Active Life ◽  
Molting Process ◽  
Pharyngeal Apparatus

Encystment in tardigrades is relatively poorly understood. It is seen as an adaptive strategy evolved to withstand unfavorable environmental conditions. This process is an example of the epigenetic, phenotypic plasticity which is closely linked to the molting process. Thulinius ruffoi is a freshwater eutardigrade and a representative of one of the biggest eutardigrade orders. This species is able to form cysts. The ovoid-shaped cysts of this species are known from nature, but cysts may also be obtained under laboratory conditions. During encystment, the animals undergo profound morphological changes that result in cyst formation. The animals surround their bodies with cuticles that isolate them from the environment. These cuticles form a cuticular capsule (cyst wall) which is composed of three cuticles. Each cuticle is morphologically distinct. The cuticles that form the cuticular capsule are increasingly simplified. During encystment, only one, unmodified and possibly functional buccal-pharyngeal apparatus was found to be formed. Apart from the feeding apparatus, the encysted specimens also possess a set of claws, and their body is covered with its own cuticle. As a consequence, the encysted animals are fully adapted to the active life after leaving the cyst capsule.

scholarly journals Transcriptome and metabolome analyses of cold and darkness-induced pellicle cysts of Scrippsiella trochoidea

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xin Guo ◽  
Zhaohui Wang ◽  
Lei Liu ◽  
Yang Li
Keyword(s):  
Signal Transduction ◽  
Sexual Reproduction ◽  
Harmful Algal Bloom ◽  
Transcriptional Response ◽  
Tca Cycle ◽  
Adaptive Strategy ◽  
Cyst Formation ◽  
Metabolite Profile ◽  
Scrippsiella Trochoidea ◽  
Regulatory Processes

Abstract Background Dinoflagellates are a group of unicellular organisms that are a major component of aquatic eukaryotes and important contributors to marine primary production. Nevertheless, many dinoflagellates are considered harmful algal bloom (HAB) species due to their detrimental environmental and human health impacts. Cyst formation is widely perceived as an adaptive strategy of cyst-forming dinoflagellates in response to adverse environmental conditions. Dinoflagellate cysts play critical roles in bloom dynamics. However, our insight into the underlying molecular basis of encystment is still limited. To investigate the molecular processes regulating encystment in dinoflagellates, transcriptome and metabolome investigations were performed on cold and darkness-induced pellicle cysts of Scrippsiella trochoidea. Results No significant transcriptional response was observed at 2 h; however, massive transcriptome and metabolome reprogramming occurred at 5 h and in pellicle cysts. The gene-to-metabolite network demonstrated that the initial transformation from vegetative cells into pellicle cysts was highly energy demanding through the activation of catabolism, including glycolysis, β-oxidation, TCA cycle and oxidative phosphorylation, to cope with cold-darkness-induced stress. However, after transformation into pellicle cysts, the metabolism was greatly reduced, and various sugars, polyunsaturated fatty acids and amino acids accumulated to prolong survival. The identification of 56 differentially expressed genes (DEGs) related to signal transduction indicated that S. trochoidea received a cold-darkness signal that activated multiple signal transduction pathways, leading to encystment. The elevated expression of genes encoding enzymes involved in ROS stress suggested that pellicle cysts respond to increased oxidative stress. Several cell cycle-related genes were repressed. Intriguingly, 11 DEGs associated with sexual reproduction suggested that pellicle cysts (or some portion thereof) may be a product of sexual reproduction. Conclusions This study provides the first transcriptome and metabolome analyses conducted during the encystment of S. trochoidea, an event that requires complex regulatory mechanisms and impacts on population dynamics. The results reveal comprehensive molecular regulatory processes underlying life cycle regulation in dinoflagellates involving signal transduction, gene expression and metabolite profile, which will improve our ability to understand and monitor dinoflagellate blooms.

scholarly journals The Impact of Different Environmental Conditions during Vegetative Propagation on Growth, Survival, and Biochemical Characteristics in Populus Hybrids in Clonal Field Trial

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 892
Author(s):  
Valda Gudynaitė-Franckevičienė ◽  
Alfas Pliūra
Keyword(s):  
Climate Change ◽  
Phenotypic Plasticity ◽  
Environmental Conditions ◽  
Vegetative Propagation ◽  
Genotypic Variation ◽  
Hybrid Poplar ◽  
Field Trials ◽  
Biochemical Traits ◽  
Suburban Areas ◽  
Growing Conditions

To have a cleaner environment, good well-being, and improve the health of citizens it is necessary to expand green urban and suburban areas using productive and adapted material of tree species. The quality of urban greenery, resistance to negative climate change factors and pollution, as well as efficiency of short-rotation forestry in suburban areas, depends primarily on the selection of hybrids and clones, suitable for the local environmental conditions. We postulate that ecogenetic response, phenotypic plasticity, and genotypic variation of hybrid poplars (Populus L.) grown in plantations are affected not only by the peculiarities of hybrids and clones, but also by environmental conditions of their vegetative propagation. The aim of the present study was to estimate growth and biochemical responses, the phenotypic plasticity, genotypic variation of adaptive traits, and genetically regulated adaptability of Populus hybrids in field trials which may be predisposed by the simulated contrasting temperature conditions at their vegetative propagation phase. The research was performed with the 20 cultivars and experimental clones of one intraspecific cross and four different interspecific hybrids of poplars propagated under six contrasting temperature regimes in phytotron. The results suggest that certain environmental conditions during vegetative propagation not only have a short-term effect on tree viability and growth, but also can help to adapt to climate change conditions and grow successfully in the long-term. It was found that tree growth and biochemical traits (the chlorophyll A and B, pigments content and the chlorophyll A/B ratio) of hybrid poplar clones grown in field trials, as well as their traits’ genetic parameters, were affected by the rooting-growing conditions during vegetative propagation phase. Hybrids P. balsamifera × P. trichocarpa, and P. trichocarpa × P. trichocarpa have shown the most substantial changes of biochemical traits across vegetative propagation treatments in field trial. Rooting-growing conditions during vegetative propagation had also an impact on coefficients of genotypic variation and heritability in hybrid poplar clones when grown in field trials.

scholarly journals Phenotypic plasticity at fine-grained spatial scales: the scorched mussel Perumytilus purpuratus growing on Patagonian rocky salt-marshes

2020 ◽  
Vol 84 (4) ◽  
pp. 393-401
Author(s):  
Yamila Gonzalez Giorgis ◽  
María Cruz Sueiro ◽  
Federico Márquez
Keyword(s):  
Phenotypic Plasticity ◽  
Environmental Conditions ◽  
Range Expansion ◽  
Salt Marshes ◽  
Spatial Scales ◽  
Shell Shape ◽  
Patch Type ◽  
Fine Grained ◽  
Perumytilus Purpuratus ◽  
Ecological Range

Understanding phenotypic plasticity of species at different spatial scales is vital in the current context of an increasing pace of environmental changes. Through this knowledge, it is possible to predict their potential to adapt and/or evolve in face of new environmental conditions such as climate change, and/or to understand their ecological range expansion. In Patagonian rocky salt-marshes, one of the most abundant invertebrate species is the scorched mussel Perumytilus purpuratus. In this system, this mussel can be found inhabiting both vegetated and non-vegetated patches, which differ in critical environmental conditions. We performed a field study evaluating whether mussels growing in vegetated patches differ in shell shape from those growing in adjacent non-vegetated patches. We sampled individuals from both patch types and assessed their shell shape and size using geometric morphometrics. The results showed that mussels from vegetated patches had shells that were more dorsoventrally expanded, anterodorsally restricted and globose in shape than those from non-vegetated patches, which showed the opposite traits resulting in a more elongated shell. The differences found could be driven by the different conditions of temperature, desiccation rate, wave action and population density to which mussels are exposed in each patch type. These results revealed the striking phenotypic plasticity of shell form of this native species at a fine-grained scale, which could be one of the explanations for its success in its ecological range expansion.

Phenotypic plasticity of the montane vole (Microtus montanus) in unpredictable environments

1992 ◽  
Vol 70 (11) ◽  
pp. 2121-2124 ◽  
Author(s):  
Norman C. Negus ◽  
Patricia J. Berger ◽  
Aelita J. Pinter
Keyword(s):  
Phenotypic Plasticity ◽  
Breeding Season ◽  
Growth Rates ◽  
Adaptive Strategy ◽  
Severe Drought ◽  
Microtus Montanus ◽  
Age Cohort ◽  
Montane Meadow ◽  
Study Sites ◽  
Breeding Seasons

From 1987 to 1989, the cohort dynamics of Microtus montanus populations were studied at two montane meadow sites approximately 160 km apart, in northwestern Wyoming. The 1987 and 1988 breeding seasons differed markedly from each other. In 1987, melt off occurred in April, and the first cohort was born in May (cohort 1). The entire breeding season was favorable owing to frequent rainfall throughout the summer. Cohort 1 animals grew rapidly and females began breeding at 4–5 weeks of age. Likewise, cohort 2 (June) animals exhibited rapid growth and females were breeding at 7–8 weeks of age. Cohort 3 (July and August) animals grew more slowly and most entered the winter as prepubertal animals of subadult size. At the end of the summer, cohort 3 animals represented >70% of the voles recruited during the breeding season. In 1988, following melt off in late April, precipitation was below normal and the situation intensified to severe drought through the summer. The growth rates of cohort 1 and 2 animals were significantly lower than 1987 growth rates, and very few females attained sexual maturity. At the end of the summer, cohort 3 animals represented <25% of the total recruitment at both study sites. Such apparent phenotypic plasticity of growth and maturation appears to be an evolved adaptive strategy that is responsive to several environmental cues. Both study sites, although widely separated, exhibited virtually identical patterns throughout the study.

scholarly journals DNA topoisomerase IIIβ promotes cyst generation by inducing cyst wall protein gene expression in Giardia lamblia

Open Biology ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 190228
Author(s):  
Chin-Hung Sun ◽  
Shih-Che Weng ◽  
Jui-Hsuan Wu ◽  
Szu-Yu Tung ◽  
Li-Hsin Su ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cyst Wall ◽  
Giardia Lamblia ◽  
Drug Targets ◽  
Cyst Formation ◽  
Dna Topoisomerase ◽  
Catalytic Core ◽  
Mutant Proteins ◽  
Cleavage Activity

Giardia lamblia causes waterborne diarrhoea by transmission of infective cysts. Three cyst wall proteins are highly expressed in a concerted manner during encystation of trophozoites into cysts. However, their gene regulatory mechanism is still largely unknown. DNA topoisomerases control topological homeostasis of genomic DNA during replication, transcription and chromosome segregation. They are involved in a variety of cellular processes including cell cycle, cell proliferation and differentiation, so they may be valuable drug targets. Giardia lamblia possesses a type IA DNA topoisomerase (TOP3β) with similarity to the mammalian topoisomerase IIIβ. We found that TOP3β was upregulated during encystation and it possessed DNA-binding and cleavage activity. TOP3β can bind to the cwp promoters in vivo using norfloxacin-mediated topoisomerase immunoprecipitation assays. We also found TOP3β can interact with MYB2, a transcription factor involved in the coordinate expression of cwp1-3 genes during encystation. Interestingly, overexpression of TOP3β increased expression of cwp1 - 3 and myb2 genes and cyst formation. Microarray analysis confirmed upregulation of cwp1-3 and myb2 genes by TOP3β. Mutation of the catalytically important Tyr residue, deletion of C-terminal zinc ribbon domain or further deletion of partial catalytic core domain reduced the levels of cleavage activity, cwp1-3 and myb2 gene expression, and cyst formation. Interestingly, some of these mutant proteins were mis-localized to cytoplasm. Using a CRISPR/Cas9 system for targeted disruption of top3β gene, we found a significant decrease in cwp1-3 and myb2 gene expression and cyst number. Our results suggest that TOP3β may be functionally conserved, and involved in inducing Giardia cyst formation.

scholarly journals Pre-akinete formation in Zygnema sp. from polar habitats is associated with metabolite re-arrangement

2020 ◽  
Vol 71 (11) ◽  
pp. 3314-3322 ◽  
Author(s):  
Erwann Arc ◽  
Martina Pichrtová ◽  
Ilse Kranner ◽  
Andreas Holzinger
Keyword(s):  
Environmental Conditions ◽  
Morphological Changes ◽  
Tca Cycle ◽  
Survival Strategies ◽  
Polar Regions ◽  
Akinete Formation ◽  
Metabolite Profiles ◽  
Dividing Cells ◽  
Storage Products ◽  
Chloroplast Morphology

Abstract In streptophytic green algae in the genus Zygnema, pre-akinete formation is considered a key survival strategy under extreme environmental conditions in alpine and polar regions. The transition from young, dividing cells to pre-akinetes is associated with morphological changes and the accumulation of storage products. Understanding the underlying metabolic changes could provide insights into survival strategies in polar habitats. Here, GC-MS-based metabolite profiling was used to study the metabolic signature associated with pre-akinete formation in Zygnema sp. from polar regions under laboratory conditions, induced by water and nutrient depletion, or collected in the field. Light microscopy and TEM revealed drastic changes in chloroplast morphology and ultrastructure, degradation of starch grains, and accumulation of lipid bodies in pre-akinetes. Accordingly, the metabolite profiles upon pre-akinete formation reflected a gradual shift in metabolic activity. Compared with young cells, pre-akinetes showed an overall reduction in primary metabolites such as amino acids and intermediates of the tricarboxylic acid (TCA) cycle, consistent with a lower metabolic turnover, while they accumulated lipids and oligosaccharides. Overall, the transition to the pre-akinete stage involves re-allocation of photosynthetically fixed energy into storage instead of growth, supporting survival of extreme environmental conditions.

Phenotypic plasticity of yield and related traits in rainfed durum wheat

2013 ◽  
Vol 152 (6) ◽  
pp. 873-884 ◽  
Author(s):  
R. MOHAMMADI
Keyword(s):  
Phenotypic Plasticity ◽  
Durum Wheat ◽  
Environmental Conditions ◽  
Linear Models ◽  
Agronomic Traits ◽  
Grain Weight ◽  
High Yield ◽  
Yield Improvement ◽  
Modern Cultivar ◽  
Breeding Lines

SUMMARYRainfall and temperature are unpredictable in Mediterranean environments, which results in inconsistent environmental conditions for crop growth and a critical source of uncertainty for farmers and growers. The objectives of the present study were to: (i) quantify and compare the plasticity of durum breeding lines, a modern cultivar and landraces on the basis of yield and agronomic traits and (ii) study associations between plasticity of yield and plasticity of agronomic and phenological traits. Plasticity was quantified using linear models for 11 durum breeding lines, one modern cultivar and two landraces grown in 21 diversified environments. The results showed that the effects due to environment, genotype and genotype×environment (G×E) interaction were significant, which indicates the existence of differences among genotypes for plasticity. Yield ranged from 1939 to 2419 kg/ha across environments and the range of plasticity was 0·66–1·13. The breeding lines and the modern cultivar had higher grain yields compared with the landraces at the same level of plasticity. The landraces with below-average plasticity in yield were characterized as tall in stature and late in heading and maturity, whereas the breeding lines and modern cultivar with above-average plasticity in yield were early in heading and maturity, semi-dwarf and high-yielding, which indicates the success in breeding the materials for unpredictable environmental conditions. In conclusion, yield plasticity was associated with yield improvement and high yield plasticity tends to associate with earliness, shorter plants and low grain weight.

scholarly journals Annual reversible plasticity of feeding structures: cyclical changes of jaw allometry in a sea urchin

2014 ◽  
Vol 281 (1779) ◽  
pp. 20132284 ◽  
Author(s):  
Thomas A. Ebert ◽  
José Carlos Hernández ◽  
Sabrina Clemente
Keyword(s):  
Sea Urchin ◽  
Pacific Coast ◽  
Morphological Changes ◽  
Linear Trend ◽  
Strongylocentrotus Purpuratus ◽  
Environmental Stressors ◽  
Feeding Apparatus ◽  
The North ◽  
Plastic Responses ◽  
Multiple Episodes

A wide variety of organisms show morphologically plastic responses to environmental stressors but in general these changes are not reversible. Though less common, reversible morphological structures are shown by a range of species in response to changes in predators, competitors or food. Theoretical analysis indicates that reversible plasticity increases fitness if organisms are long-lived relative to the frequency of changes in the stressor and morphological changes are rapid. Many sea urchin species show differences in the sizes of jaws (demi-pyramids) of the feeding apparatus, Aristotle's lantern, relative to overall body size, and these differences have been correlated with available food. The question addressed here is whether reversible changes of relative jaw size occur in the field as available food changes with season. Monthly samples of the North American Pacific coast sea urchin Strongylocentrotus purpuratus were collected from Gregory Point on the Oregon (USA) coast and showed an annual cycle of relative jaw size together with a linear trend from 2007 to 2009. Strongylocentrotus purpuratus is a long-lived species and under field conditions individuals experience multiple episodes of changes in food resources both seasonally and from year to year. Their rapid and reversible jaw plasticity fits well with theoretical expectations.

scholarly journals Predation selects for smaller eye size in a vertebrate: effects of environmental conditions and sex

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182625 ◽  
Author(s):  
Richard Svanbäck ◽  
Frank Johansson
Keyword(s):  
Visual Acuity ◽  
Phenotypic Plasticity ◽  
Experimental Evidence ◽  
Predation Risk ◽  
Environmental Conditions ◽  
Retinal Image ◽  
The Other ◽  
Eye Size ◽  
Fish Predators ◽  
Resource Levels

Increased eye size in animals results in a larger retinal image and thus improves visual acuity. Thus, larger eyes should aid both in finding food as well as detecting predators. On the other hand, eyes are usually very conspicuous and several studies have suggested that eye size is associated with predation risk. However, experimental evidence is scant. In this study, we address how predation affects variation in eye size by performing two experiments using Eurasian perch juveniles as prey and either larger perch or pike as predators. First, we used large outdoor tanks to compare selection due to predators on relative eye size in open and artificial vegetated habitats. Second, we studied the effects of both predation risk and resource levels on phenotypic plasticity in relative eye size in indoor aquaria experiments. In the first experiment, we found that habitat altered selection due to predators, since predators selected for smaller eye size in a non-vegetated habitat, but not in a vegetated habitat. In the plasticity experiment, we found that fish predators induced smaller eye size in males, but not in females, while resource levels had no effect on eye size plasticity. Our experiments provide evidence that predation risk could be one of the driving factors behind variation in eye size within species.

scholarly journals Morpho-anatomical features of underground systems in six Asteraceae species from the Brazilian Cerrado

2011 ◽  
Vol 83 (3) ◽  
pp. 981-992 ◽  
Author(s):  
Beatriz Appezzato-da-Glória ◽  
Graziela Cury
Keyword(s):  
Environmental Conditions ◽  
Lateral Roots ◽  
Adaptive Strategy ◽  
Herbaceous Species ◽  
Bud Bank ◽  
Brazilian Cerrado ◽  
Neotropical Savanna ◽  
Anatomical Features ◽  
Paulo State ◽  
Vegetation Regeneration

In the Brazilian Cerrado (neotropical savanna), the development of bud-bearing underground systems as adaptive structures to fire and dry periods can comprise an important source of buds for this ecosystem, as already demonstrated in the Brazilian Campos grasslands and North American prairies. Asteraceae species from both woody and herbaceous strata have subterranean organs that accumulate carbohydrates, reinforcing the adaptive strategy of these plants to different environmental conditions. This study aims to analyse the morpho-anatomy of underground systems of six species of Asteraceae (Mikania cordifolia L.f. Willd., Mikania sessilifolia DC, Trixis nobilis (Vell.) Katinas, Pterocaulon alopecuroides (Lam.) DC., Vernonia elegans Gardner and Vernonia megapotamica Spreng.), to describe these structures and to verify the occurrence and origin of shoot buds, and to analyse the presence of reserve substances. Individuals sampled in Cerrado areas in São Paulo State showed thick underground bud-bearing organs, with adventitious or lateral roots and presence of fructans. Xylopodium was found in all studied species, except for Trixis nobilis, which had stem tuber. The presence of fructans as reserve, and the capacity of structures in the formation of buds indicate the potential of herbaceous species of Asteraceae in forming a viable bud bank for vegetation regeneration in the Brazilian Cerrado.

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