VBA-AMF: A VBA Program Based on the Magnified Intersections Method for Quantitative Recording of Root Colonization by Arbuscular Mycorrhizal Fungi
INDIAN JOURNAL OF MICROBIOLOGY
Authors: Hu, Wentao; Pan, Lan; Chen, Hui; Tang, Ming
The extent of mycorrhizal fungi colonization is an important factor for determining the function of mycorrhizal fungi in fungi-host interaction, and quantifying the extent of mycorrhizal fungi colonization is a fundamental and essential task for researchers engaged in mycorrhizal studies. Intersect methods, such as the gridline intersect and magnified intersections methods, are accurate and objective, and are widely used to assess the colonization status of arbuscular mycorrhizal (AM) fungus. However, no convenient procedures or add-ins for Excel spreadsheets have been developed to simplify these methods. Here, we propose a procedure using the Visual Basic for Application (VBA) program in Excel that is based on the magnified intersections method, which we refer to as VBA-AMF (arbuscular mycorrhizal fungi). Time-saving and convenience are the two most prominent advantages of the VBA-AMF procedure, as it enables researchers to compute the colonization rate of AM fungi in roots, and consequently the extent of root colonization by AM fungi. VBA-AMF can also be modified to measure the status of other fungal colonizations in plant roots following the same strategy.
Synaptic Transmission from Somatostatin-expressing Interneurons to Excitatory Neurons Mediated by alpha 5-subunit-containing GABA(A) Receptors in the Developing Visual Cortex
Authors: Cao, Jun-Wei; Guan, Wuqiang; Yu, Yong-Chun; Fu, Yinghui
Dendrite-targeting somatostatin-expressing interneurons (SST-INs) powerfully control signal integration and synaptic plasticity in pyramidal dendrites during cortical development. We previously showed that synaptic transmission from SST-INs to pyramidal cells (PCs) (SST-IN -> PC) in the mouse visual cortex suddenly declined at around the second postnatal week. However, it is unclear what specific postsynaptic mechanisms underlie this developmental change. Using multiple whole-cell patch-clamp recordings, we found that application of an alpha 5-GABA(A) receptor-selective inverse agonist, alpha5IA, significantly weakened SST-IN -> PC unitary inhibitory postsynaptic currents (uIPSCs) in layer 2/3 of the mouse visual cortex, but had no effect on uIPSCs from SST-INs to other types of interneurons. The extent of alpha5IA-induced reduction of SST-IN -> PC synaptic transmission was significantly larger at postnatal days 11-13 (P11-13) than P14-17. Moreover, alpha 5-subunit-containing GABA(A) receptors (alpha 5-GABA(A)Rs)-mediated uIPSCs had slow rise and decay kinetics. Apart from pharmacological test, we observed that SST-IN -> PC synapses did indeed contain alpha 5-GABAARs by immunogold labeling for electron microscopy. More importantly, coinciding with the weakening of SST-IN -> PC synaptic transmission, the number of alpha 5-GABA(A)R particles in SST-IN -> PC synapses significantly decreased at around the second postnatal week. Together, these data indicate that alpha 5-GABA(A)Rs are involved in synaptic transmission from SST-INs to PCs in the neocortex, and are significantly diminished around the second postnatal week. (C) 2020 IBRO. Published by Elsevier Ltd. All rights reserved.