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921.
Daniel F. Q. Smith Emma Camacho Raviraj Thakur Alexander J. Barron Yuemei Dong George Dimopoulos Nichole A. Broderick Arturo Casadevall 《PLoS biology》2021,19(5)
Melanin, a black-brown pigment found throughout all kingdoms of life, has diverse biological functions including UV protection, thermoregulation, oxidant scavenging, arthropod immunity, and microbial virulence. Given melanin’s broad roles in the biosphere, particularly in insect immune defenses, it is important to understand how exposure to ubiquitous environmental contaminants affects melanization. Glyphosate—the most widely used herbicide globally—inhibits melanin production, which could have wide-ranging implications in the health of many organisms, including insects. Here, we demonstrate that glyphosate has deleterious effects on insect health in 2 evolutionary distant species, Galleria mellonella (Lepidoptera: Pyralidae) and Anopheles gambiae (Diptera: Culicidae), suggesting a broad effect in insects. Glyphosate reduced survival of G. mellonella caterpillars following infection with the fungus Cryptococcus neoformans and decreased the size of melanized nodules formed in hemolymph, which normally help eliminate infection. Glyphosate also increased the burden of the malaria-causing parasite Plasmodium falciparum in A. gambiae mosquitoes, altered uninfected mosquito survival, and perturbed the microbial composition of adult mosquito midguts. Our results show that glyphosate’s mechanism of melanin inhibition involves antioxidant synergy and disruption of the reaction oxidation–reduction balance. Overall, these findings suggest that glyphosate’s environmental accumulation could render insects more susceptible to microbial pathogens due to melanin inhibition, immune impairment, and perturbations in microbiota composition, potentially contributing to declines in insect populations.Glyphosate, the most commonly used herbicide in the world, inhibits the production of melanin. Melanin is an important pigment and a key component of the insect immune system; this study shows that glyphosate weakens insects’ melanin-based immune system and makes them more vulnerable to infections, including with the human malaria parasite Plasmodium falciparum. 相似文献
922.
923.
Ana C. Certal Ana M. Sanchez Harri Kokko W. Broothaerts M. Margarida Oliveira José A. Feijó 《Sexual plant reproduction》1999,12(2):94-98
The molecular bases of self-incompatibility have been intensively studied in a restricted number of model species, but for
most families the expression and distribution of S-proteins is unknown. In this work, pistil cryosections from apple were
used for in situ detection of S-proteins. Two specific antibodies, one against the S3-protein and another against all apple
S-proteins were used. S-proteins were shown to be localised in the intercellular space of the transmitting tissue, both in
the stigma and style, which agrees with the proposed mechanism of action for S-RNases in gametophytic self-incompatibility.
Some intracellular labelling was also observed in all ovary sections, confined to one layer of the nucellus surrounding the
embryo sac, but this labelling was found to be non-S-allele-specific. Nevertheless, the signal in the ovary was tissue-specific, which may indicate that some component not encoded
by the S-locus but similar to S-proteins was detected. To the best of our knowledge this is the first report on the precise
distribution of S-RNases in a rosaceous species.
Received: 15 July 1998 / Revision accepted: 29 December 1998 相似文献
924.
Mediterranean ecosystems are inherently patchy, challenging habitat-use behavior. Certain mammalian carnivores take advantage of this patchiness by a strategy of habitat complementation/supplementation, which is invariant to the scale of analysis. To test if the same behavior is adopted by the stone marten, we used a combined data set of capture and radio-tracking data at three scales of analysis (1-m, 25-m, and 452-m radius plots). We used compositional analysis to test if there were sex-specific differences in foraging and resting habitat use of stone martens and if these patterns were affected by the presence of other mesocarnivores. Our results showed that stone martens are found both in rural and forested landscapes. Foraging and resting activities occurred far from roads in large and complex patches of cork oak woodlands, riparian vegetation, orchards, and pastureland. Use varied with the scale of analysis and the sex. At smaller scales, females use pastures for foraging and orchards for resting, whereas riparian vegetation and sparse cork oak forests influenced this use at larger scales. Males, on the other hand, were more consistent across scales, using riparian areas and dense cork oak woodlands for foraging and pastures for resting. Stone martens shared the same areas with other coexisting mesocarnivores. Stone martens use cork oak woodlands and complement/supplement this use with other land cover types. The consistent use of cork oak woodlands across scales emphasizes the importance of this land cover to the preservation of functional Mediterranean ecosystems in southern Portugal. 相似文献
925.
Ana Margarida Capelo Sónia Silva Gina Brito Conceição Santos 《Plant Cell, Tissue and Organ Culture》2010,103(2):237-242
We describe a protocol for somatic embryogenesis (SE) induction from an adult wild olive tree (Olea
europaea ssp. europaea var. sylvestris. The protocol used confirms for the first time that there is no need to use juvenile or rejuvenated material for SE induction.
For SE induction, petiole and leaf (proximal, intermediary and distal zones) explants were grown on Murashige and Skoog (MS)
or Olive Medium (OM) media with different combinations of plant growth regulators (PGR): α- naphthaleneacetic acid (NAA),
Zeatin (Zea), indole-3-butyric acid (IBA), 2-isopentyl adenine (2iP), thidiazuron (TDZ) and 6-benzylaminopurine (BAP). All
media had 30 g/l sucrose and 7 g/l agar, and the pH was adjusted to 5.8. Cultures were incubated in the dark and, after 3 months,
they were transferred to MS medium without PGR for expression. Petiole explants gave the highest callus production, while
for SE induction and expression distal blade leaf and petiole explants gave the highest rates. The best medium for SE induction
was MS with 12.25 μM IBA plus 4.56 μM Zea. Histological analyses confirmed the individuality of globular somatic embryos.
This is the first report of SE expression in explants without rejuvenation in Olea genus, and opens perspectives for using this strategy in SE protocols both for this wild genotype and for commercial genotypes. 相似文献
926.
William F Paolo Jr Ekaterina Dadachova Piyali Mandal Arturo Casadevall Paul J Szaniszlo Joshua D Nosanchuk 《BMC microbiology》2006,6(1):55-16
Background
Wangiella dermatitidis is a human pathogenic fungus that is an etiologic agent of phaeohyphomycosis. W. dermatitidis produces a black pigment that has been identified as a dihydroxynaphthalene melanin and the production of this pigment is associated with its virulence. Cell wall pigmentation in W. dermatitidis depends on the WdPKS1 gene, which encodes a polyketide synthase required for generating the key precursor for dihydroxynaphthalene melanin biosynthesis. 相似文献927.
Pedro Beja Luís Gordinho Luís Reino Filipa Loureiro Margarida Santos-Reis Rui Borralho 《European Journal of Wildlife Research》2009,55(3):227-238
The interaction between hunting interests and legally protected predators is often a contentious conservation problem, requiring
detailed understanding of predator responses to game management. This issue was addressed in southern Portugal in a treatment-control
natural experiment, whereby the abundances of small game, corvids, birds of prey and carnivores were compared in 12 game estates
(>500 ha) and 12 matching areas with similar sizes and land uses but no game management. European rabbits (Oryctolagus cuniculus), Iberian hares (Lepus granatensis) and, less so, red-legged partridges (Alectoris rufa) were far more numerous in game estates than elsewhere. Among legally controlled species, there were less Eurasian jays (Garrulus glandarius) but more red foxes (Vulpes vulpes) in game estates, though the latter were primary targets of predator culling. Fox abundance within game estates varied inversely
with an index of management intensity (density of small game feeding sites) and increased along with hare abundance. As for
protected species, only common kestrels (Falco tinnunculus) and genets (Genetta genetta) were fewer in game estates. The abundance of raptors within game estates varied inversely with gamekeeper density, whereas
that of common buzzards (Buteo buteo) increased along with rabbit abundance. Overall, there was little evidence that game management reduced local predator abundances,
except in the most intensively managed estates. Game estates provided concentrations of prey that was scarce elsewhere, which
may have favoured increased abundances of some predators. Further investigations are needed to find out whether high prey
densities may attract predators to game estates with increased mortality risk, which may thus become population sinks for
protected species. 相似文献
928.
929.
930.
Margarida A. Ferreira A.Correia Alves M.Áurea Cruz Costa M.Isabel Paul 《Phytochemistry》1977,16(1):117-120
The naphthoquinone dimers natalenone, 8′-hydroxydiospyrin and euclanone and the trimers galpinone and a compound with MW 562 were isolated from E. natalensis roots. Natalenone is a dehydrodimer of 7-methyl- juglone with the two moieties linked by two CC bonds to give a fused tetracyclic structure, one ring bearing a methylene bridge. Galpinone is a 7-methyljuglone linear trimer, the three units probably being linked C-8-C-6′and C-3′-C-3″. Euclanone is a new dimer of 7-methyljuglone and methylnaphthazarin, isomeric with 8′-hydroxydiospyrin. 相似文献