Chlorophyll ‘a’ fluorescence Induction kinetics of Ipomoea pes-caprae Sweet, under salinity stress

The present investigation was made to the effect of exogenous addition of different concentrations of NaCl (100 – 500mM) and NaCl:CaCl2 (100mM + 1mM to 300mM + 3mM) on growth and photochemical activities of Ipomoea pes-caprae. The upper limit of NaCl and NaCl:CaCl2 salinity for the survival of this seedlings at 500mM NaCl and 300mM + 3mM NaCl:CaCl2 and the favourable growth was observed at 200mM NaCl and 100mM + 1mM NaCl:CaCl2 respectively. Beyond these concentrations the growth rate was declined sharply. The polarographic measurements with isolated mesophyll cell showed enhanced activities of PSI (DCPIPH2àMV), PSII (H2OàDCPIP) and whole chain electron transport (H2OàMV) upto optimum salinity level of both treatments. At higher salinities, all the photochemical activities reduced drastically. Fast and slow cholorphyll ‘a’ fluorescence transients were recorded using intake leaves obtained from control and saline treated plants. Various levels of slow chl ‘a’ fluorescence induction kinetics    (P, P-S, M, T) showed an increasing activity at 200mM NaCl and 100mM + 1mM NaCl:CaCl2 and thereafter its gradually declined. P/T was directly measured as photosystem II activities. The similar trend was followed to fast chlorophyll ‘a’ fluorescence at different levels such as Fo, Fv, Fm and the ratio Fv/Fm significantly enhanced the rate of photosynthetic activities upto optimal level of both salinity

Opposing Cholinergic and Serotonergic Modulation of Layer 6 in Prefrontal Cortex

Prefrontal cortex is a hub for attention processing and receives abundant innervation from cholinergic and serotonergic afferents. A growing body of evidence suggests that acetylcholine (ACh) and serotonin (5-HT) have opposing influences on tasks requiring attention, but the underlying neurophysiology of their opposition is unclear. One candidate target population is medial prefrontal layer 6 pyramidal neurons, which provide feedback modulation of the thalamus, as well as feed-forward excitation of cortical interneurons. Here, we assess the response of these neurons to ACh and 5-HT using whole cell recordings in acute brain slices from mouse cortex. With application of exogenous agonists, we show that individual layer 6 pyramidal neurons are bidirectionally-modulated, with ACh and 5-HT exerting opposite effects on excitability across a number of concentrations. Next, we tested the responses of layer 6 pyramidal neurons to optogenetic release of endogenous ACh or 5-HT. These experiments were performed in brain slices from transgenic mice expressing channelrhodopsin in either ChAT-expressing cholinergic neurons or Pet1-expressing serotonergic neurons. Light-evoked endogenous neuromodulation recapitulated the effects of exogenous neurotransmitters, showing opposing modulation of layer 6 pyramidal neurons by ACh and 5-HT. Lastly, the addition of 5-HT to either endogenous or exogenous ACh significantly suppressed the excitation of pyramidal neurons in prefrontal layer 6. Taken together, this work suggests that the major corticothalamic layer of prefrontal cortex is a substrate for opposing modulatory influences on neuronal activity that could have implications for regulation of attention

Crystal Structure And Hirshfeld Surface Analysis Of 1-[(1-Butyl-1H-1,2,3-Triazol-4-Yl)Meth­Yl]-3-Methyl­Quinoxalin-2(1H)-One

The title compound is built up from a planar quinoxalinone ring system linked through a methyl­ene bridge to a 1,2,3-triazole ring, which is inclined by 67.09 (4)° to the quinoxalinone ring plane., The title compound, C16H19N5O, is built up from a planar quinoxalinone ring system linked through a methyl­ene bridge to a 1,2,3-triazole ring, which in turn carries an n-butyl substituent. The triazole ring is inclined by 67.09 (4)° to the quinoxalinone ring plane. In the crystal, the mol­ecules form oblique stacks along the a-axis direction through inter­molecular C—HTrz⋯NTrz (Trz = triazole) hydrogen bonds, and offset π-stacking inter­actions between quinoxalinone rings [centroid–centroid distance = 3.9107 (9) Å] and π–π inter­actions, which are associated pairwise by inversion-related C—HDhydqn⋯π(ring) (Dhydqn = di­hydro­quinoxaline) inter­actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (52.7%), H⋯N/N⋯H (18.9%) and H⋯C/C⋯H (17.0%) inter­actions.PubMedScopu