Time-dependent effects of perfluorinated compounds on viability in cerebellar granule neurons: Dependence on carbon chain length and functional group attached

AbstractAmong the plethora of catalytic methods developed for hydrocarbofunctionalization of olefins to date, reactions that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond to afford branched products are scarce. Here, we show that a Ni-based catalyst in conjunction with a stoichiometric reducing agent promote Markovnikov-selective hydroalkylation of unactivated alkenes tethered to a recyclable 8-aminoquinaldine directing auxiliary. These mild reductive processes employ readily available primary and secondary haloalkanes as both the hydride and alkyl donor. Reactions of alkenyl amides with ≥ five-carbon chain length regioselectively afforded β-alkylated products through remote hydroalkylation, underscoring the fidelity of the catalytic process and the directing group’s capability in stabilizing five-membered nickelacycle intermediates. The operationally simple protocol exhibits exceptional functional group tolerance and is amenable to the synthesis of bioactive molecules as well as regioconvergent transformations.

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Molecular Features of Odorants Systematically Influence Slow Temporal Responses Across Clusters of Coordinated Antennal Lobe Units in the Moth Manduca sexta

Journal of Neurophysiology ◽

10.1152/jn.01132.2003 ◽

2004 ◽

Vol 92 (1) ◽

pp. 236-254 ◽

Cited By ~ 30

Author(s):

Kevin C. Daly ◽

Geraldine A. Wright ◽

Brian H. Smith

Keyword(s):

Chain Length ◽

Manduca Sexta ◽

Antennal Lobe ◽

Functional Group ◽

Carbon Chain ◽

Stimulus Generalization ◽

Carbon Chain Length ◽

Molecular Features ◽

Behavioral Studies ◽

Cross Correlation Analysis

Behavioral studies of olfactory discrimination and stimulus generalization in many species indicate that the molecular features of monomolecular odorants are important for odor discrimination. Here we evaluate how features, such as carbon chain length and functional group, are represented in the first level of synaptic processing. We recorded antennal lobe ensemble responses in the moth Manduca sexta to repeated 100-ms pulses of monomolecular alcohols and ketones. Most units exhibited a significant change in spike rate in response to most odorants that outlasted the duration of the stimulus. Peristimulus data were then sampled over 780 ms for each pulse of all odorants. Factor analysis was used to assess whether there were groups of units with common response patterns. We found that factors identified and represented activity for clusters of units with common temporal response characteristics. These temporally patterned responses typically spanned 780 ms and were often dependent on carbon chain length and functional group. Furthermore, cross-correlation analysis frequently indicated significant coincident spiking even during spontaneous activity. However, this synchrony occurred mainly between units recorded on the same tetrode. In a final analysis, the Euclidean distance between odor responses was calculated for each pair of odorants using factors as dimensions. The distance between responses for any two odorants was maximized by ∼240 ms. This time course corresponded to the brief sequence of coordinated bursts across the recorded population. The distance during this period was also a function of systematic differences in molecular features. Results of this Euclidian analysis thus directly correlate to previous behavioral studies of stimulus generalization in M. sexta.

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Alkyl Halides as Both Hydride and Alkyl Sources in Catalytic Regioselective Reductive Olefin Hydroalkylation

10.26434/chemrxiv.12675368.v1 ◽

2020 ◽

Author(s):

Xianxiao Chen ◽

Weidong Rao ◽

Tao Yang ◽

Ming Joo Koh

Keyword(s):

Chain Length ◽

Functional Group ◽

Carbon Chain ◽

Reducing Agent ◽

Alkyl Halides ◽

Bioactive Molecules ◽

Catalytic Process ◽

Carbon Chain Length ◽

Simple Protocol

Among the plethora of catalytic methods developed for hydrocarbofunctionalization of olefins to date, reactions that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond to afford branched products are scarce. Here, we show that a Ni-based catalyst in conjunction with a stoichiometric reducing agent promote Markovnikov-selective hydroalkylation of unactivated alkenes tethered to a recyclable 8-aminoquinaldine directing auxiliary. These mild reductive processes employ readily available primary and secondary haloalkanes as both the hydride and alkyl donor, obviating the need for additional hydrosilane, acidic or basic additives. Reactions of alkenyl amides with ≥five-carbon chain length regioselectively afforded β-alkylated products through remote hydroalkylation, underscoring the fidelity of the catalytic process and the directing group's capability in stabilizing five-membered nickelacycle intermediates. The operationally simple protocol exhibits exceptional functional group tolerance and is amenable to the synthesis of bioactive molecules as well as regioconvergent transformations.

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Alkyl Halides as Both Hydride and Alkyl Sources in Catalytic Regioselective Reductive Olefin Hydroalkylation

10.26434/chemrxiv.12675368 ◽

2020 ◽

Author(s):

Xianxiao Chen ◽

Weidong Rao ◽

Tao Yang ◽

Ming Joo Koh

Keyword(s):

Chain Length ◽

Functional Group ◽

Carbon Chain ◽

Reducing Agent ◽

Alkyl Halides ◽

Bioactive Molecules ◽

Catalytic Process ◽

Carbon Chain Length ◽

Simple Protocol

Among the plethora of catalytic methods developed for hydrocarbofunctionalization of olefins to date, reactions that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond to afford branched products are scarce. Here, we show that a Ni-based catalyst in conjunction with a stoichiometric reducing agent promote Markovnikov-selective hydroalkylation of unactivated alkenes tethered to a recyclable 8-aminoquinaldine directing auxiliary. These mild reductive processes employ readily available primary and secondary haloalkanes as both the hydride and alkyl donor, obviating the need for additional hydrosilane, acidic or basic additives. Reactions of alkenyl amides with ≥five-carbon chain length regioselectively afforded β-alkylated products through remote hydroalkylation, underscoring the fidelity of the catalytic process and the directing group's capability in stabilizing five-membered nickelacycle intermediates. The operationally simple protocol exhibits exceptional functional group tolerance and is amenable to the synthesis of bioactive molecules as well as regioconvergent transformations.

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Effect of chemical structure on the sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances (PFASs)

Environmental Science Water Research & Technology ◽

10.1039/c6ew00150e ◽

2016 ◽

Vol 2 (6) ◽

pp. 975-983 ◽

Cited By ~ 20

Author(s):

Nerea Abad Fernandez ◽

Lucia Rodriguez-Freire ◽

Manish Keswani ◽

Reyes Sierra-Alvarez

Keyword(s):

Chain Length ◽

Chemical Structure ◽

Functional Group ◽

Carbon Chain ◽

Carbon Chain Length ◽

Polyfluoroalkyl Substances ◽

Perfluoroalkyl And Polyfluoroalkyl Substances

The study provides insights into the effect of carbon chain length, functional group substitutions and chemical structure on sonochemical degradation of perfluoroalkyl and polyfluoroalkyl substances.

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Alkyl Halides as Both Hydride and Alkyl Sources in Catalytic Regioselective Reductive Olefin Hydroalkylation

10.26434/chemrxiv.12675368.v2 ◽

2020 ◽

Author(s):

Xianxiao Chen ◽

Weidong Rao ◽

Tao Yang ◽

Ming Joo Koh

Keyword(s):

Chain Length ◽

Functional Group ◽

Carbon Chain ◽

Reducing Agent ◽

Alkyl Halides ◽

Bioactive Molecules ◽

Catalytic Process ◽

Carbon Chain Length ◽

Simple Protocol

Among the plethora of catalytic methods developed for hydrocarbofunctionalization of olefins to date, reactions that regioselectively install a functionalized alkyl unit at the 2-position of a terminal unactivated C=C bond to afford branched products are scarce. Here, we show that a Ni-based catalyst in conjunction with a stoichiometric reducing agent promote Markovnikov-selective hydroalkylation of unactivated alkenes tethered to a recyclable 8-aminoquinaldine directing auxiliary. These mild reductive processes employ readily available primary and secondary haloalkanes as both the hydride and alkyl donor, obviating the need for additional hydrosilane, acidic or basic additives. Reactions of alkenyl amides with ≥five-carbon chain length regioselectively afforded β-alkylated products through remote hydroalkylation, underscoring the fidelity of the catalytic process and the directing group's capability in stabilizing five-membered nickelacycle intermediates. The operationally simple protocol exhibits exceptional functional group tolerance and is amenable to the synthesis of bioactive molecules as well as regioconvergent transformations.

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Reactive Oxygen Species Evoked by Potassium Deprivation and Staurosporine Inactivate Akt and Induce the Expression of TXNIP in Cerebellar Granule Neurons

Oxidative Medicine and Cellular Longevity ◽

10.1155/2017/8930406 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 5

Author(s):

Marco Antonio Zaragoza-Campillo ◽

Julio Morán

Keyword(s):

Reactive Oxygen Species ◽

Neuronal Apoptosis ◽

Reactive Oxygen ◽

Time Dependent ◽

Akt Pathway ◽

Cerebellar Granule Neurons ◽

Dependent Manner ◽

Granule Neurons ◽

Oxygen Species ◽

Cerebellar Granule

The reactive oxygen species (ROS) play a critical role in neuronal apoptosis; however, the mechanisms are not well understood. It has been shown that thioredoxin-interacting protein (TXNIP) overexpression renders cells more susceptible to oxidative stress and promotes apoptosis and that the activation of PI3K/Akt pathway leads to a downregulation of TXNIP. Here, we evaluated the role of ROS in the regulation of Akt activity and the subsequent regulation of the TXNIP expression in a model of apoptotic death of cerebellar granule neurons (CGN). We observed that two apoptotic conditions that generate ROS at short times led to an increase in the expression of TXNIP in a time-dependent manner; antioxidants significantly reduced this expression. Also,H2O2caused an increase in TXNIP expression. Moreover, apoptotic conditions induced inactivation of Akt in a time-dependent manner similar to TXNIP expression andH2O2treatment led to Akt inactivation. Besides, the pharmacological inhibition of Akt increases TXNIP expression and induces CGN cell death. Together, these results suggest that ROS promote neuronal apoptosis through the Akt-TXNIP signaling pathway, supporting the idea that the PI3K/Akt pathway regulates the TXNIP expression. This study highlights the potential importance of this mechanism in neuronal death.

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