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- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Li, Zhao-Tian, et al.
(author)
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Selective resource allocation may promote a sex ratio in pollinator fig wasps more beneficial for the host tree
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6:1
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Journal article (peer-reviewed)abstract
- Mutualisms play a key role in most ecosystems, yet the mechanisms that prevent overexploitation of the mutualistic relationship are still poorly understood. In the mutualism between fig trees and their pollinating wasps both partners depend on each other. Fig trees benefit from female wasps that disperse their pollen, whereas wasps frequently benefit from a higher ratio of male offspring. Here we use manipulative field experiments to address whether host trees (Ficus racemosa) can influence the offspring sex ratio of the pollinator wasp. We controlled wasp matings; virgin wasps can lay only male eggs. We found that virgin foundress wasps had fewer offspring than mated foundresses. This was not caused by virgin wasps having a shorter lifespan, or laying fewer eggs. Instead, male wasp larvae were more likely to die during development. Additionally, male eggs were deposited in flowers of equal style length to those of female eggs, yet emerged from galls with shorter pedicels than those of female wasps. We suggest that male larvae are either allocated less resources by the tree, or are less able to attract resources, during development. If the tree orchestrates this difference it would promote a more female-biased wasp brood, thus increasing the tree’s fitness.
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| 3. |
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| 4. |
- Miao, Bai-Ge, et al.
(author)
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Active pollination in a functionally dioecious Ficus species : An interplay between pollinator behaviour and floral morphology
- 2023
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In: Flora. - : Elsevier. - 0367-2530 .- 1618-0585. ; 302
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Journal article (peer-reviewed)abstract
- Active pollination has evolved four times in brood site pollination mutualisms. When pollination is active, the pollinator's behaviour specifically evolves to ensure flower fertilisation. In functionally dioecious Ficus species, the male figs host pollinating wasp larvae, while wasps cannot breed in the female figs because the styles are longer than the wasp ovipositor. Here we investigate the dioecious Ficus hispida. We show that in male figs, every time the wasp has laid an egg into a pistillate flower, it removes one pollen grain from its pollen pockets and places it on the hypopygium. When the wasp inserts its ovipositor into the next flower, the pollen grain is deposited deep within the style. Each ovipositor insertion results in flower pollination and insect oviposition. Because of systematic pollination of the flowers into which the eggs are laid, the wasp larvae benefit from feeding on fertilised endosperm while no seed are produced. In female figs, after probing a flower, the wasp presents pollination behaviour only every five visits. However, if it does occur, this behaviour lasts longer than in male figs and results in the deposition of on average 10 pollen grains on the hypopygium. The exposed sticky papillae on the stigmatic surface collect pollen from the hypopygium and pollen tubes may grow to neighbouring stigmas, ensuring secondary dispersal and efficient ovule fertilisation. Overall, our study demonstrates that the floral morphology of male figs facilitates precise pollen deposition, beneficial for the wasp progeny, while the floral morphology of female figs compensates for wasp pollination behaviour that is not selected in those figs. We conclude that the morphology of the arena in which interactions with its pollinator are played out is the result of selection on the plant to maximize its male and female fitness. Incidentally, this morphology stabilises the mutualistic interaction.
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| 5. |
- Zhang, Ting, et al.
(author)
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The evolution of parasitism from mutualism in wasps pollinating the fig, Ficus microcarpa, in Yunnan Province, China
- 2021
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 118:32
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Journal article (peer-reviewed)abstract
- Theory identifies factors that can undermine the evolutionary stability of mutualisms. However, theory's relevance to mutualism stability in nature is controversial. Detailed comparative studies of parasitic species that are embedded within otherwise mutualistic taxa (e.g., fig pollinator wasps) can identify factors that potentially promote or undermine mutualism stability. We describe results from behavioral, morphological, phylogenetic, and experimental studies of two functionally distinct, but closely related, Eupristina wasp species associated with the monoecious host fig, Ficus microcarpa, in Yunnan Province, China. One (Eupristina verticillata) is a competent pollinator exhibiting morphologies and behaviors consistent with observed seed production. The other (Eupristina sp.) lacks these traits, and dramatically reduces both female and male reproductive success of its host. Furthermore, observations and experiments indicate that individuals of this parasitic species exhibit greater relative fitness than the pollinators, in both indirect competition (individual wasps in separate fig inflorescences) and direct competition (wasps of both species within the same fig). Moreover, phylogenetic analyses suggest that these two Eupristina species are sister taxa. By the strictest definition, the nonpollinating species represents a "cheater" that has descended from a beneficial pollinating mutualist. In sharp contrast to all 15 existing studies of actively pollinated figs and their wasps, the local F. microcarpa exhibit no evidence for host sanctions that effectively reduce the relative fitness of wasps that do not pollinate. We suggest that the lack of sanctions in the local hosts promotes the loss of specialized morphologies and behaviors crucial for pollination and, thereby, the evolution of cheating.
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