Nanoparticle-host interactions in natural systems

Ocean Viruses: On Their Abundance, Diversity, and Target Hosts

Quantitative Viral Ecology ◽

10.23943/princeton/9780691161549.003.0006 ◽

2016 ◽

Author(s):

Joshua S. Weitz

Keyword(s):

Functional Diversity ◽

Cross Infection ◽

Viral Diversity ◽

Virus Species ◽

Community Based ◽

Natural Systems ◽

Host Interactions ◽

Hierarchical Order ◽

Virus Like Particle ◽

Virus Abundance

This chapter introduces the theoretical and modeling approaches necessary to estimate (i) viral abundance, (ii) viral diversity, and (iii) virus–host interactions. Viruses are extremely abundant in the oceans, with estimates of virus-like particle densities ranging from approximately 104 to 108/ml. Virus abundance is estimated to be at its highest in coastal environments, during blooms, and in sediments. Viral diversity remains elusive. Those features of viral diversity that are estimable include Shannon and Simpson diversity, and should be utilized instead of attempting to estimate the total number of virus “species” in the community based on measurements of a small subsample. Viral diversity includes genotypic, genetic, and functional diversity. Individual viruses infect more than one host type, and individual hosts are infected by more than one virus. The cross-infection networks in natural systems include evidence of specialization, as measured by modularity, and hierarchical order, as measured by nestedness.

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Nanoparticle host interactions in natural systems

Nanoscopic approaches in Earth and planetary sciences ◽

10.1180/emu-notes.2010.emu8-8 ◽

2010 ◽

pp. 325-376 ◽

Cited By ~ 1

Author(s):

U. Becker ◽

M. Reich ◽

S. Biswas

Keyword(s):

Natural Systems ◽

Host Interactions

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The ecological consequences of a pandemic

Biology Letters ◽

10.1098/rsbl.2020.0641 ◽

2020 ◽

Vol 16 (11) ◽

pp. 20200641

Author(s):

Julia C. Buck ◽

Sara B. Weinstein

Keyword(s):

Infectious Disease ◽

Environmental Impacts ◽

Indirect Effects ◽

Human Behaviour ◽

Disease Avoidance ◽

Global Response ◽

Predator Prey ◽

Natural Systems ◽

Host Interactions ◽

Economic And Social Impacts

The COVID-19 pandemic has altered human behaviour in profound ways, prompting some to question whether the associated economic and social impacts might outweigh disease impacts. This fits into a burgeoning ecological paradigm suggesting that for both predator–prey and parasite–host interactions, non-consumptive effects (avoidance) can be orders of magnitude stronger than consumptive effects (sickness and death). Just as avoidance of predators and parasites imposes substantial costs on prey and hosts, altered behaviour to reduce the transmission of COVID-19 has impacted human fitness and wellbeing. But the effects of infectious disease avoidance do not stop there; non-consumptive effects of predators and parasites often trigger cascading indirect effects in natural systems. Similarly, shifts in human behaviour due to COVID-19 have triggered myriad indirect effects on species and the environment, which can be positive, negative or neutral. We urge researchers to recognize that the environmental impacts associated with lockdowns are indirect effects of the virus. In short, the global response to COVID-19 suggests that the non-consumptive effects of a pathogen, and resulting indirect effects, can be profound.

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Effect of Iron Limitation on the Ultrastructure of Agmenellum Quadruplicatum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098551 ◽

1981 ◽

Vol 39 ◽

pp. 410-411

Author(s):

L. P. Hardie ◽

D. L. Balkwill ◽

S. E. Stevens

Keyword(s):

Growth Medium ◽

Green Alga ◽

Natural Habitat ◽

Iron Limitation ◽

Natural Environments ◽

Blue Green Alga ◽

Marine Cyanobacterium ◽

Natural Systems ◽

Thin Sectioning ◽

Agmenellum Quadruplicatum

Agmenellum quadruplicatum is a unicellular, non-nitrogen-fixing, marine cyanobacterium (blue-green alga). The ultrastructure of this organism, when grown in the laboratory with all necessary nutrients, has been characterized thoroughly. In contrast, little is known of its ultrastructure in the specific nutrient-limiting conditions typical of its natural habitat. Iron is one of the nutrients likely to limit this organism in such natural environments. It is also of great importance metabolically, being required for both photosynthesis and assimilation of nitrate. The purpose of this study was to assess the effects (if any) of iron limitation on the ultrastructure of A. quadruplicatum. It was part of a broader endeavor to elucidate the ultrastructure of cyanobacteria in natural systemsActively growing cells were placed in a growth medium containing 1% of its usual iron. The cultures were then sampled periodically for 10 days and prepared for thin sectioning TEM to assess the effects of iron limitation.

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