scholarly journals Rare phytomyxid infection on the alien seagrass Halophila stipulacea in the southeast Aegean Sea

2017 ◽  
pp. 433 ◽  
Author(s):  
MARTIN VOHNÍK ◽  
ONDŘEJ BOROVEC ◽  
ELIF ÖZGÜR ÖZBEK ◽  
EMINE ŞÜKRAN OKUDAN ASLAN
Keyword(s):  
Developmental Stages ◽  
Higher Plants ◽  
Marine Ecosystem ◽  
Aegean Sea ◽  
Life Cycles ◽  
Host Cells ◽  
Cymodocea Nodosa ◽  
Halophila Stipulacea ◽  
Halophila Ovalis ◽  
Marine Diversity

Phytomyxids (Phytomyxea) are obligate endosymbionts of many organisms such as algae, diatoms, oomycetes and higher plants including seagrasses. Despite their supposed significant roles in the marine ecosystem, our knowledge of their marine diversity and distribution as well as their life cycles is very limited. Here we describe anatomy and morphology of several developmental stages of a phytomyxid symbiosis recently discovered on the petioles of the alien seagrass Halophila stipulacea (Forssk.) Asch. at a locality in the southeast Aegean Sea. Its earliest whitish stages appeared already on the youngest leaves at the apex of the newly formed rhizomes. The infected host cells grew in volume being filled with plasmodia which resulted in the formation of characteristic macroscopic galls. The plasmodia eventually cleaved into spores and in the final stage recorded by us, the dark brown to black galls contained mature resting spores often occurring in duplexes and possessing thick verrucous outer walls. Based on its anatomo-morphological features the phytomyxid was assigned as Plasmodiophora cf. halophilae. Little is so far known about the origins and eco-physiological functioning of this rare symbiosis. However, seemingly similar infection patterns were reported in 1913 on Halophila ovalis (R. Br.) Hook. f. from Java and in 1995 on H. stipulacea from Sicily. Since H. stipulacea is of the Indo-Pacific origin and no phytomyxid infection was observed on the co-occurring autochthonous seagrass Cymodocea nodosa, we hypothesize that its phytomyxid might have co-migrated into the Mediterranean through the Suez Canal, potentially reaching as far as the southern Ionian Sea.

Basic Biology of Trypanosoma Cruzi

2020 ◽  
Vol 26 ◽  
Author(s):  
Aline Araujo Zuma ◽  
Emile dos Santos Barrias ◽  
Wanderley de Souza
Keyword(s):  
Trypanosoma Cruzi ◽  
Trypanosoma Brucei ◽  
Cell Biology ◽  
Structural Organization ◽  
Developmental Stages ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Cellular Organization ◽  
Basic Biology ◽  
Comparative Information

Abstract:: The present review addresses basic aspects of the biology of the pathogenic protozoa Trypanosoma cruzi and some comparative information with Trypanosoma brucei. Like eukaryotic cells, their cellular organization is similar to that of mammalian hosts. However, these parasites present structural particularities. That is why the following topics are emphasized in this paper: developmental stages of the life cycle in the vertebrate and invertebrate hosts; the cytoskeleton of the protozoa, especially the sub-pellicular microtubules; the flagellum and its attachment to the protozoan body through specialized junctions; the kinetoplast-mitochondrion complex, including its structural organization and DNA replication; the glycosome and its role in the metabolism of the cell; the acidocalcisome, describing its morphology, biochemistry, and functional role; the cytostome and the endocytic pathway; the organization of the endoplasmic reticulum and Golgi complex; the nucleus, describing its structural organization during interphase and division; and the process of interaction of the parasite with host cells. The unique characteristics of these structures also make them interesting chemotherapeutic targets. Therefore, further understanding of cell biology aspects contributes to the development of drugs for chemotherapy.

scholarly journals Lankesterella (Apicomplexa, Lankesterellidae) Blood Parasites of Passeriform Birds: Prevalence, Molecular and Morphological Characterization, with Notes on Sporozoite Persistence In Vivo and Development In Vitro

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1451
Author(s):  
Carolina Romeiro Fernandes Chagas ◽  
Josef Harl ◽  
Vytautas Preikša ◽  
Dovilė Bukauskaitė ◽  
Mikas Ilgūnas ◽  
...  
Keyword(s):  
Morphological Characterization ◽  
Life Cycles ◽  
Diagnostic Methods ◽  
Host Cells ◽  
Blood Parasites ◽  
Serinus Canaria ◽  
Long Time ◽  
Development In Vitro

Recent studies confirmed that some Hepatozoon-like blood parasites (Apicomplexa) of birds are closely related to the amphibian parasite Lankesterella minima. Little is known about the biology of these pathogens in birds, including their distribution, life cycles, specificity, vectors, and molecular characterization. Using blood samples of 641 birds from 16 species, we (i) determined the prevalence and molecular diversity of Lankesterella parasites in naturally infected birds; (ii) investigated the development of Lankesterella kabeeni in laboratory-reared mosquitoes, Culex pipiens forma molestus and Aedes aegypti; and (iii) tested experimentally the susceptibility of domestic canaries, Serinus canaria, to this parasite. This study combined molecular and morphological diagnostic methods and determined 11% prevalence of Lankesterella parasites in Acrocephalidae birds; 16 Lankesterella lineages with a certain degree of host specificity and two new species (Lankesterella vacuolata n. sp. and Lankesterella macrovacuolata n. sp.) were found and characterized. Lankesterella kabeeni (formerly Hepatozoon kabeeni) was re-described. Serinus canaria were resistant after various experimental exposures. Lankesterella sporozoites rapidly escaped from host cells in vitro. Sporozoites persisted for a long time in infected mosquitoes (up to 42 days post exposure). Our study demonstrated a high diversity of Lankesterella parasites in birds, and showed that several avian Hepatozoon-like parasites, in fact, belong to Lankesterella genus.

Observing microscopic phases of lichen life cycles on transparent substrata placed in situ

2005 ◽  
Vol 37 (5) ◽  
pp. 373-382 ◽  
Author(s):  
William B. SANDERS
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Life Cycles ◽  
Potential Significance ◽  
Free Living ◽  
Lichen Community ◽  
One Year ◽  
The One ◽  
Observation Period

The utility of plastic cover slips as a substratum for in situ study of lichen developmental stages is further explored in a neotropical foliicolous lichen community and in a European temperate corticolous community. Twenty-one months after placement in the tropical forest, the cover slips bore foliicolous lichen thalli with several species producing characteristic ascocarps and ascospores, indicating the suitability of the substratum for completion of the life cycle of these lichens. On cover slips placed within the temperate corticolous community, lichen propagules anchored to the substratum with relatively short attachment hyphae but did not develop further within the one year observation period. Intimately intermixed microbial communities of short-celled, mainly pigmented fungi and chlorophyte algae developed upon the transparent substratum. Among the algae, Trebouxia cells, often in groups showing cell division and without associated lichenizing hyphae, were commonly observed. The potential significance of the free-living populations in the life cycle of Trebouxia and in those of Trebouxia-associated lichen fungi is discussed.

scholarly journals Suppression of influenza A virus replication in human lung epithelial cells by noncytotoxic concentrations bafilomycin A1

2015 ◽  
Vol 308 (3) ◽  
pp. L270-L286 ◽  
Author(s):  
Behzad Yeganeh ◽  
Saeid Ghavami ◽  
Andrea L. Kroeker ◽  
Thomas H. Mahood ◽  
Gerald L. Stelmack ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Host Cell ◽  
Influenza A Virus ◽  
Influenza A ◽  
Life Cycles ◽  
Host Cells ◽  
Nuclear Accumulation ◽  
Low Concentration ◽  
High Concentrations ◽  
The Impact

Subcellular trafficking within host cells plays a critical role in viral life cycles, including influenza A virus (IAV). Thus targeting relevant subcellular compartments holds promise for effective intervention to control the impact of influenza infection. Bafilomycin A1(Baf-A1), when used at relative high concentrations (≥10 nM), inhibits vacuolar ATPase (V-ATPase) and reduces endosome acidification and lysosome number, thus inhibiting IAV replication but promoting host cell cytotoxicity. We tested the hypothesis that much lower doses of Baf-A1also have anti-IAV activity, but without toxic effects. Thus we assessed the antiviral activity of Baf-A1at different concentrations (0.1–100 nM) in human alveolar epithelial cells (A549) infected with IAV strain A/PR/8/34 virus (H1N1). Infected and mock-infected cells pre- and cotreated with Baf-A1were harvested 0–24 h postinfection and analyzed by immunoblotting, immunofluorescence, and confocal and electron microscopy. We found that Baf-A1had disparate concentration-dependent effects on subcellular organelles and suppressed affected IAV replication. At concentrations ≥10 nM Baf-A1inhibited acid lysosome formation, which resulted in greatly reduced IAV replication and release. Notably, at a very low concentration of 0.1 nM that is insufficient to reduce lysosome number, Baf-A1retained the capacity to significantly impair IAV nuclear accumulation as well as IAV replication and release. In contrast to the effects of high concentrations of Baf-A1, very low concentrations did not exhibit cytotoxic effects or induce apoptotic cell death, based on morphological and FACS analyses. In conclusion, our results reveal that low-concentration Baf-A1is an effective inhibitor of IAV replication, without impacting host cell viability.

scholarly journals Ontogenetic disparity in early planktic foraminifers

2020 ◽  
Vol 39 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Sophie Kendall ◽  
Felix Gradstein ◽  
Christopher Jones ◽  
Oliver T. Lord ◽  
Daniela N. Schmidt
Keyword(s):  
Surface Area ◽  
Unit Volume ◽  
Developmental Stages ◽  
High Surface ◽  
High Surface Area ◽  
Morphological Plasticity ◽  
Life Cycles ◽  
Ct Scanner ◽  
Metabolic Demand ◽  
Planktic Foraminifera

Abstract. Changes in morphology during ontogeny can have profound impacts on the physiology and biology of a species. Studies of ontogenetic disparity through time are rare because of the lack of preservation of developmental stages in the fossil record. As they grow by incremental chamber accretion and retain evidence of growth in their shell, planktic foraminifera are an ideal group for the study ontogenetic disparity through the evolution of a higher taxon. Here, we quantify different developmental stages in Jurassic foraminifers and infer the evolutionary implications of the shape of these earliest representatives of the group. Using a Zeiss Xradia micro-CT scanner, the development of Globuligerina bathoniana and Globuligerina oxfordiana from the Bathonian sediments of Gnaszyn, Poland, and Globuligerina balakhmatovae and Globuligerina tojeiraensis from the Kimmeridgian Tojeira Formation of Portugal was reconstructed. Disparity is low through the early evolution of planktic foraminifers. The number of chambers and range in surface area per unit volume are lower than in modern specimens. We interpret this morphology as an indication of opportunistic behaviour. The low morphological plasticity during the juvenile stage suggests that strong constraints on the juveniles, described in the modern ocean, were already acting on Jurassic specimens. The high surface area per unit volume in these developmental stages points towards the need to satisfy a higher metabolic demand than in the adult specimens. We are interpreting the lower chamber numbers as indicative of short life cycles and potentially rapid reproduction, both of which may have allowed these species to exploit the nutrient-rich waters of the Jurassic Tethys Ocean.

scholarly journals Poseidon: A marine environmental monitoring, forecasting and information system for the Greek seas

2000 ◽  
Vol 1 (1) ◽  
pp. 71 ◽  
Author(s):  
T.H. SOUKISSIAN ◽  
G. CHRONIS
Keyword(s):  
Marine Ecosystem ◽  
Coastal Zone Management ◽  
Aegean Sea ◽  
Sea Transport ◽  
Marine Research ◽  
Zone Management ◽  
Operational Oceanography ◽  
Monitoring And Forecasting ◽  
Forecasting System ◽  
Marine Environmental

The scope of this work is twofold: i) to discuss and analyze some principles, issues and problems related to the development and advancement of Operational Oceanography in Greece and ii) to present a real-time monitoring and forecasting system for the Aegean Sea, which is currently under implementation. Operational Oceanography in Greece has become a necessity today, since it can provide aid to find solutions on problems related to societal, economic, environmental and scientific issues. Most of the Greek coastal regions are under pressure, susceptible to damages due to the increasing tendency of the population to move from the inland to the coast, marine environmental pollution, competitive development of the coastal market sector, etc. Moreover, the complex geomorphology of the coastal areas and the interdependence between natural processes and human activities causes significant alterations in this delicate environment. A rational treatment of these problems can be based on integrated coastal zone management (ICZM). An absolutely necessary means for establishing ICZM is the operation of marine moni- toring systems. Such a system ("POSEIDON system") is under implementation by the National Centre for Marine Research. POSEIDON is a comprehensive marine monitoring and forecasting system, that aims to improve environmental surveillance and facilitate sea transport, rescue and safety of life at sea, fishing and aquaculture, protection of the marine ecosystem, etc. POSEIDON is expected to enhance considerably the capabilities to manage, protect and develop the marine resources of the Greek Seas and to promote Greek Operational Oceanography.

scholarly journals Feeding and ecomorphology of three clupeoids in the N Aegean Sea

2013 ◽  
Vol 15 (1) ◽  
pp. 9 ◽  
Author(s):  
P. K. KARACHLE ◽  
K. I. STERGIOU
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Aegean Sea ◽  
Life Cycles ◽  
Mouth Area ◽  
Morphological Features ◽  
Sardina Pilchardus ◽  
Intestine Length ◽  
Sardinella Aurita ◽  
The Individual

The present study examines the feeding habits of anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and round sardinella (Sardinella aurita). The results are combined with previously published information on feeding-related morphological features (i.e. mouth area, intestine length and tail area) in order to explore morphological affinities between species and the effect of ecomorphology on their co-existence. These species were mainly zooplanktivorous and no dietary differences were found with sex and season. Anchovy preyed mainly on Crustacea larvae, whereas sardine and round sardinella on Copepoda. In the majority of cases (>90%), the individual fractional trophic level of all species ranged between 3.0 and 3.5, classifying them as omnivores with preference to animals. The feeding-related morphological features differed between anchovy and the two other species, whereas only intestine length differed between sardine and round sardinella. The fact that round sardinella’s diet and morphology show a greater resemblance to those of sardine, further support the hypothesis that is a particulate feeder as sardine. Hence the three species tend to exploit the same food resources differently throughout the year. Thus, they make best use of the environment and its resources, in order to avoid competition and achieve optimum feeding conditions throughout their life cycles

scholarly journals ORF4 of the Temperate Archaeal Virus SNJ1 Governs the Lysis-Lysogeny Switch and Superinfection Immunity

2020 ◽  
Vol 94 (16) ◽  
Author(s):  
Beibei Chen ◽  
Zhao Chen ◽  
Yuchen Wang ◽  
Han Gong ◽  
Linshan Sima ◽  
...  
Keyword(s):  
Life Cycle ◽  
Bioinformatic Analysis ◽  
Model System ◽  
Life Cycles ◽  
Host Cells ◽  
Biological Functions ◽  
Mechanistic Studies ◽  
Cultivation Conditions ◽  
Archaeal Virus ◽  
Archaeal Viruses

ABSTRACT Recent environmental and metagenomic studies have considerably increased the repertoire of archaeal viruses and suggested that they play important roles in nutrient cycling in the biosphere. However, very little is known about how they regulate their life cycles and interact with their hosts. Here, we report that the life cycle of the temperate haloarchaeal virus SNJ1 is controlled by the product ORF4, a small protein belonging to the antitoxin MazE superfamily. We show that ORF4 controls the lysis-lysogeny switch of SNJ1 and mediates superinfection immunity by repression of genomic DNA replication of the superinfecting viruses. Bioinformatic analysis shows that ORF4 is highly conserved in two SNJ1-like proviruses, suggesting that the mechanisms for lysis-lysogeny switch and superinfection immunity are conserved in this group of viruses. As the lysis-lysogeny switch and superinfection immunity of archaeal viruses have been poorly studied, we suggest that SNJ1 could serve as a model system to study these processes. IMPORTANCE Archaeal viruses are important parts of the virosphere. Understanding how they regulate their life cycles and interact with host cells provide crucial insights into their biological functions and the evolutionary histories of viruses. However, mechanistic studies of the life cycle of archaeal viruses are scarce due to a lack of genetic tools and demanding cultivation conditions. Here, we discover that the temperate haloarchaeal virus SNJ1, which infects Natrinema sp. strain J7, employs a lysis-lysogeny switch and establishes superinfection immunity like bacteriophages. We show that its ORF4 is critical for both processes and acts as a repressor of the replication of SNJ1. These results establish ORF4 as a master regulator of SNJ1 life cycle and provides novel insights on the regulation of life cycles by temperate archaeal viruses and on their interactions with host cells.

Anuran life history plasticity: Variable practice in determining the end-point of larval development

2010 ◽  
Vol 31 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Patrick Thomas Walsh
Keyword(s):  
Life History ◽  
Developmental Stages ◽  
Life Cycles ◽  
Developmental Phase ◽  
Larval Phase ◽  
End Point ◽  
Anuran Amphibians ◽  
Individual Fitness ◽  
Metamorphic Climax ◽  
Size At Metamorphosis

AbstractPlasticity in the timing of life history events and their impact on individual fitness, particularly the timing of and size at metamorphosis in animals with complex life cycles such as anuran amphibians, has long been of interest to ecologists. For different studies on life history plasticity to be comparable, there must be clearly defined and commonly agreed transition points, but it is unclear how consistently this is being performed in studies using anuran amphibians. In a review of 157 published studies, I found considerable variation in defining the end point of the larval phase. While a slight majority used the emergence of the forelimbs as the conclusion of the larval phase, some used a period within the developmental phase of metamorphic climax and others used the resorption of the tail. Studies included in this review, that assessed the same life history variable at two different developmental stages, reported some differences in results depending on which developmental stage was used. Recent evidence also shows that metamorphic climax is itself a period which can vary with environmental conditions, but, even in studies that included part or all of metamorphic climax in the larval phase, the treatment of individuals during metamorphic climax was not reported. Therefore, I argue that life history studies on anuran amphibians should distinguish the following phases: larval, metamorphic climax, juvenile, adult; that the end of the larval phase is best defined in ecological studies by forelimb emergence and that conditions under which individuals undergo metamorphic climax should be fully described.

scholarly journals Population Dynamics of the ‘Golden Tides’ Seaweed, Sargassum horneri, on the Southwestern Coast of Korea: The Extent and Formation of Golden Tides

2020 ◽  
Vol 12 (7) ◽  
pp. 2903 ◽  
Author(s):  
Sun Kyeong Choi ◽  
Hyun-Ju Oh ◽  
Suk-Hyun Yun ◽  
Hyuk Je Lee ◽  
Kyounghoon Lee ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Marine Ecosystem ◽  
Life Cycles ◽  
Sargassum Horneri ◽  
Gene Markers ◽  
Average Biomass ◽  
Environmental Difference ◽  
Few Data ◽  
Specific Growth Rates

Since 2015, troublesome masses of floating Sargassum horneri have been introduced via ocean currents and winds to the southwestern coastline of Korea, including Jeju Island. These massive mats have caused considerable damage to the aquaculture industry, tourism, and the marine ecosystem. Most previous studies of S. horneri have focused on cultivation, the development of gene markers, and photosynthetic activity, but few data on population dynamics are available. We investigated the population dynamics of native S. horneri off the southwestern coast of Korea with the aim of predicting the formation of golden tides. Populations at two sites had obligate annual life cycles. Thalli were recruited during the period September–November, grew during the period December–April, and senesced by July. This pattern reflected seasonal trends in water temperature. Specific growth rates and heights of the thalli at Munseom were significantly higher than those at Jindo. The greatest environmental difference between the two sites is probably the degree of exposure to wave action. Mortality density (thalli lost per unit area) in the Munseom population was highest during the period December–January (i.e., 2–3 months after recruitment) and in March. Most thalli in the Jindo population died off in July when water temperatures increased. The maximum average biomass of S. horneri thalli detaching from the substrata reached 1.6 kg fresh weight m–2 during January and March. Thus, large-scale drifting mats were formed by S. horneri detachment from the substrata. Despite the differences in space and environment between China and Korea, our findings will enable quantitative assessments of the overall floating Sargassum biomass in the East China and Yellow Seas.

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