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101.
Our previous investigation of the naturally occurring indolecompounds in barley and tomato shoots suggested that the biosynthesisof indol-3yl-acetic acid (IAA) from tryptophan might proceedvia either the indol-3yl-pyruvic acid or tryptamine pathwaysin both species. The results further indicated that the indol-3yl-lacticacid pathway for IAA formation might also be operative in tomato.In the present study, tryptophan-3-14C and tryptamine-2-14Cwere fed to excised shoots of both barley and tomato, and indol-3yl-lacticacid-3-14C was also fed to shoots of tomato. All three compoundswere found to give rise to radioactive IAA with little dilutionin specific activity. Feeding tryptophan-3-14C also resultedin the labelling of indol-3yl-pyruvic acid, indol-3yl-acetaldehyde,and tryptamine, which were isolated and chemically identifiedfrom both species, and radioactive indol-3yl-lactic acid andtryptophol were also produced in tomato. Indol-3yl-acetaldehydewas found to be labelled in both species after administrationof tryptamine-2-14C, while the principal metabolite of indol-3yl-lacticacid-3-14C was radioactive tryptophan. These findings, alongwith the results from a quantitative study of the radioactivemetabolites, indicate that both the indol-3yl-pyruvic acid andtryptamine pathways can operate in both species, while the formationof IAA from indol-3yl-lactic acid in tomato probably occursindirectly, via tryptophan. These conclusions were supportedby the demonstration of the enzymes, L-tryptophan transaminase,L-trypto-phan decarboxylase, and indol-3yl-acetaldehyde dehydrogenasein cell-free extracts of both tissues, and of indol-3yl-pyruvicacid decarboxylase in the tomato extract. No indol-3yl-lacticacid decarboxylase activity was observed in the extracts fromeither tissue. 相似文献
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M. S. SANTOS E. C. GONALVES M. S. R. BARBOSA A. SILVA M. P. C. SCHNEIDER 《Molecular ecology resources》2006,6(2):307-309
Here we presented 10 polymorphic microsatellite loci obtained from scarlet ibis through an enriched genomic library. The analysis of 45 individuals from three Brazilian natural populations showed allelic diversity ranged from three to 17 alleles, observed heterozygosity ranged from 0.03 to 0.92, and expected heterozygosity ranged from 0.06 to 0.92. These highly variable microsatellite loci can provide means for assessing overall genetic variation in its remnant natural populations, which may help the development of effective conservation programs. 相似文献
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SCOTT A. SCHNEIDER JAN H. GILIOMEE JOHN W. DOOLEY BENJAMIN B. NORMARK 《Systematic Entomology》2013,38(4):805-817
The association between African armoured scale insects (Hemiptera: Coccoidea: Diaspididae) and ants belonging to Melissotarsus Emery (Hymenoptera: Formicidae: Myrmicinae) is the only trophobiosis known in which ants do not receive honeydew or nectar in exchange for protection and other services. Food reward for the ants in this mutualism remains unknown, despite repeated suggestions that diaspidids are consumed by the associated ants, thus serving as ‘domestic cattle’. We describe new observations on interactions between Melissotarsus emeryi Santschi and the diaspidid Morganella conspicua (Brain) from South Africa. Worker ants exhibited previously undescribed tending behaviours, most notably a ‘squeezing and licking’ performed on an adult female diaspidid and ‘culling’, in which a worker removed an adult female armoured scale from the host plant. These could represent the gathering of secretory products and the cultivation of an individual for consumption, respectively. An ant exclusion study over 12 days of isolation showed that adult female diaspidids and second‐instar nymphs secreted no wax or exudates that attending ants would ordinarily collect. Workers of M. emeryi did not defend their nest against invading colonies of Crematogaster and other unidentified ants: we hypothesize that the primary mode of defence is maintenance of isolation within galleries. We describe three new ant‐associated diaspidid species: Affirmaspis cederbergensis Schneider sp.n. from South Africa, Diaspis doumtsopi Schneider sp.n. from Cameroon, and Melissoaspis incola Schneider sp.n. from Madagascar. Melissoaspis formicaria (Ben‐Dov) comb.n. is transferred from Morganella (Brain). Diagnostic characteristics for Melissoaspis Ben‐Dov are revised, and additional taxonomic information defining this genus allows ease of identification. An updated identification key to the species of ant‐associated diaspidids is provided. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:632C1122-954A-4DE6-B946-8E6AB6A4D27F . 相似文献
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MARGUERITE A. XENOPOULOS CHRISTOF SCHNEIDER DAELYN A. WOOLNOUGH 《Global Change Biology》2011,17(4):1720-1732
The role of climate‐related disturbances on complex host–affiliate relationships remains understudied, largely because affiliate species vary in host use and are often differentially susceptible to disturbance relative to their hosts. Here we report the first set of host–affiliate species–discharge relationships (SDR) in freshwater and examine how anticipated shifts in water availability (flow) will impact coextirpations. We used SDR for freshwater mussels and fish across 11 regions (over 350 rivers) in the continental United States that we coupled to future water availability (2070) to model mussel and fish coextirpations. We also used river‐specific host–affiliate matrices (presence–absence) to evaluate how host‐specificity (mean number of hosts used by an affiliate) and host‐overlap (extent to which affiliates share hosts) relate to extirpation vulnerability. We found that the strength and predictability of SDR models vary geographically and that mussels were more susceptible to flow alterations than fish. These patterns of extirpations were strongest in the southeast where: (1) flow reductions are expected to be greatest; (2) more species are lost per unit flow; (3) and more mussels are expected to be lost per unit of fish. We also found that overall mussel losses associated with reduction in habitat (water availability) were greater than those associated with loss of fish hosts which we assumed to be a function of host redundancy. These findings highlight the utility of SDR as a tool for conservation efforts but they also demonstrate the potential severity of reductions in mussel and fish richness as consequence of climate change and water use. Mussels provide key ecosystem services but face multiple pronged attacks from reductions in flow, habitat, and fish hosts. These losses in biodiversity and ecosystem functions can translate into major effects on food webs and nutrient recycling. 相似文献
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