17 research outputs found

    Blackcaps fruit consumption

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    fruit consumption among blackcaps in 5 water treatments: 1. ad libitum MAMT fruits, but only for five hours each day + saline solution of 0.6 ml NaCl 0.9% subcutaneous injection. 2. simultaneous provisioning of fruits and water for 5 hours. 3. A group provided with drinking water for five hours, and after a one-hour break, provided with MAMT fruits for five hours 4 .A group provided with MAMT fruits for five hours, and after a one-hour break, provided with drinking water for five hours. 5. A water restricted group that was provided with MAMT fruits for five hours (n = 2)

    The Effects of Nutrient Dynamics on Root Patch Choice

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    Plants have been recognized to be capable of allocating more roots to rich patches in the soil. We tested the hypothesis that in addition to their sensitivity to absolute differences in nutrient availability, plants are also responsive to temporal changes in nutrient availability. Different roots of the same Pisum sativum plants were subjected to variable homogeneous and heterogeneous temporally – dynamic and static nutrient regimes. When given a choice, plants not only developed greater root biomasses in richer patches; they discriminately allocated more resources to roots that developed in patches with increasing nutrient levels, even when their other roots developed in richer patches. These results suggest that plants are able to perceive and respond to dynamic environmental changes. This ability might enable plants to increase their performance by responding to both current and anticipated resource availabilities in their immediate proximity

    Egg production

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    Each row represents eggs laid by a group of fleas fed simultaneously on the same host

    Data from: Use it or lose it: reproductive implications of ecological specialization in a haematophagous ectoparasite

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    Using experimentally induced disruptive selection, we tested two hypotheses regarding the evolution of specialization in parasites. The ‘trade-off’ hypothesis suggests that adaptation to a specific host may come at the expense of a reduced performance when exploiting another host. The alternative ‘relaxed selection’ hypothesis suggests that the ability to exploit a given host would deteriorate when becoming obsolete. Three replicate populations of a flea Xenopsylla ramesis were maintained on each of two rodent hosts, Meriones crassus and Dipodillus dasyurus, for nine generations. Fleas maintained on a specific host species for a few generations substantially decreased their reproductive performance when transferred to an alternative host species, whereas they generally did not increase their performance on their maintenance host. The results support the ‘relaxed selection’ hypothesis of the evolution of ecological specialization in haematophagous ectoparasites, while suggesting that trade-offs are unlikely drivers of specialization. Further work is needed to study the extent by which the observed specializations are based on epigenetic or genetic modifications

    Pupation success

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    Each row represents a clutch of eggs laid at the same day by a group of females fed on the same host individua

    Emergence success

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    Each row represents a group of papae from the same clutch of eggs laid at the same day by a group of females fed on the same host individua

    Homozygous GLUL deletion is embryonically viable and leads to glutamine synthetase deficiency

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    Glutamine synthetase (GS) is the enzyme responsible for the biosynthesis of glutamine, providing the only source of endogenous glutamine necessary for several critical metabolic and developmental pathways. GS deficiency, caused by pathogenic variants in the glutamate-ammonia ligase (GLUL) gene, is a rare autosomal recessive inborn error of metabolism characterized by systemic glutamine deficiency, persistent moderate hyperammonemia, and clinically devastating seizures and multi-organ failure shortly after birth. The four cases reported thus far were caused by homozygous GLUL missense variants. We report a case of GS deficiency caused by homozygous GLUL gene deletion, diagnosed prenatally and likely representing the most severe end of the spectrum. We expand the known phenotype of this rare condition with novel dysmorphic, radiographic and neuropathologic features identified on post-mortem examination. The biallelic deletion identified in this case also included the RNASEL gene and was associated with immune dysfunction in the fetus. This case demonstrates that total absence of the GLUL gene in humans is viable beyond the embryonic period, despite the early embryonic lethality found in GLUL animal models
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