Konno K

References (4)

Title : Glyoxal fixation: An approach to solve immunohistochemical problem in neuroscience research - Konno_2023_Sci.Adv_9_eadf7084
Author(s) : Konno K , Yamasaki M , Miyazaki T , Watanabe M
Ref : Sci Adv , 9 :eadf7084 , 2023
Abstract : The gold-standard fixative for immunohistochemistry is 4% formaldehyde; however, it limits antibody access to target molecules that are buried within specialized neuronal components, such as ionotropic receptors at the postsynapse and voltage-gated ion channels at the axon initial segment, often requiring additional antigen-exposing techniques to detect their authentic signals. To solve this problem, we used glyoxal, a two-carbon atom di-aldehyde. We found that glyoxal fixation greatly improved antibody penetration and immunoreactivity, uncovering signals for buried molecules by conventional immunohistochemical procedures at light and electron microscopic levels. It also enhanced immunosignals of most other molecules, which are known to be detectable in formaldehyde-fixed sections. Furthermore, we unearthed several specific primary antibodies that were once judged to be unusable in formaldehyde-fixed tissues, allowing us to successfully localize so far controversial synaptic adhesion molecule Neuroligin 1. Thus, glyoxal is a highly effective fixative for immunostaining, and a side-by-side comparison of glyoxal and formaldehyde fixation is recommended for routine immunostaining in neuroscience research.
ESTHER : Konno_2023_Sci.Adv_9_eadf7084
PubMedSearch : Konno_2023_Sci.Adv_9_eadf7084
PubMedID: 37450597

Title : Comprehensive Analysis and Biological Characterization of Venom Components from Solitary Scoliid Wasp Campsomeriella annulata annulata - Alberto-Silva_2021_Toxins.(Basel)_13_
Author(s) : Alberto-Silva C , Vieira Portaro FC , Kodama RT , Pantaleao HQ , Inagaki H , Nihei KI , Konno K
Ref : Toxins (Basel) , 13 : , 2021
Abstract : Venoms of solitary wasps are utilized for prey capture (insects and spiders), paralyzing them with a stinger injection to be offered as food for their larvae. Thus, the identification and characterization of the components of solitary wasp venoms can have biotechnological application. In the present study, the venom components profile of a solitary scoliid wasp, Campsomeriella annulata annulata, was investigated through a comprehensive analysis using LC-MS and -MS/MS. Online mass fingerprinting revealed that the venom extract contains 138 components, and MS/MS analysis identified 44 complete sequences of the peptide components. The peptides are broadly divided into two classes: bradykinin-related peptides, and linear alpha-helical peptides. Among the components of the first class, the two main peptides, alpha-campsomerin (PRLRRLTGLSPLR) and beta-campsomerin (PRLRRLTGLSPLRAP), had their biological activities evaluated. Both peptides had no effects on metallopeptidases [human neprilysin (NEP) and angiotensin-converting enzyme (ACE)] and acetylcholinesterase (AChE), and had no cytotoxic effects. Studies with PC12 neuronal cells showed that only alpha-campsomerin was able to enhance cell viability, while beta-campsomerin had no effect. It is noteworthy that the only difference between the primary structures from these peptides is the presence of the AP extension at the C-terminus of beta-campsomerin, compared to alpha-campsomerin. Among the linear alpha-helical peptides, annulatin (ISEALKSIIVG-NH(2)) was evaluated for its biological activities. Annulatin showed histamine releasing activity from mast cells and low hemolytic activity, but no antimicrobial activities against all microbes tested were observed. Thus, in addition to providing unprecedented information on the whole components, the three peptides selected for the study suggest that molecules present in solitary scoliid wasp venoms may have interesting biological activities.
ESTHER : Alberto-Silva_2021_Toxins.(Basel)_13_
PubMedSearch : Alberto-Silva_2021_Toxins.(Basel)_13_
PubMedID: 34941722

Title : Specific Neuroligin3-alphaNeurexin1 signaling regulates GABAergic synaptic function in mouse hippocampus - Uchigashima_2020_Elife_9_
Author(s) : Uchigashima M , Konno K , Demchak E , Cheung A , Watanabe T , Keener DG , Abe M , Le T , Sakimura K , Sasaoka T , Uemura T , Imamura Kawasawa Y , Watanabe M , Futai K
Ref : Elife , 9 : , 2020
Abstract : Synapse formation and regulation require signaling interactions between pre- and postsynaptic proteins, notably cell adhesion molecules (CAMs). It has been proposed that the functions of neuroligins (Nlgns), postsynaptic CAMs, rely on the formation of trans-synaptic complexes with neurexins (Nrxns), presynaptic CAMs. Nlgn3 is a unique Nlgn isoform that localizes at both excitatory and inhibitory synapses. However, Nlgn3 function mediated via Nrxn interactions is unknown. Here we demonstrate that Nlgn3 localizes at postsynaptic sites apposing vesicular glutamate transporter 3-expressing (VGT3+) inhibitory terminals and regulates VGT3+ inhibitory interneuron-mediated synaptic transmission in mouse organotypic slice cultures. Gene expression analysis of interneurons revealed that the alphaNrxn1+AS4 splice isoform is highly expressed in VGT3+ interneurons as compared with other interneurons. Most importantly, postsynaptic Nlgn3 requires presynaptic alphaNrxn1+AS4 expressed in VGT3+ interneurons to regulate inhibitory synaptic transmission. Our results indicate that specific Nlgn-Nrxn signaling generates distinct functional properties at synapses.
ESTHER : Uchigashima_2020_Elife_9_
PubMedSearch : Uchigashima_2020_Elife_9_
PubMedID: 33355091

Title : Allosteric inhibition of nicotinic acetylcholine receptors of vertebrates and insects by philanthotoxin - Rozental_1989_J.Pharmacol.Exp.Ther_249_123
Author(s) : Rozental R , Scoble GT , Albuquerque EX , Idriss M , Sherby S , Sattelle DB , Nakanishi K , Konno K , Eldefrawi AT , Eldefrawi ME
Ref : Journal of Pharmacology & Experimental Therapeutics , 249 :123 , 1989
Abstract : The effects of pure philanthotoxin (PhTX), a component of the venom of the wasp Philanthus triangulum, were studied on nicotinic acetylcholine receptors (nAChRs) of vertebrates and insects so as to compare their sensitivities and the mechanism of action of PhTX. Electrophysiological techniques were used on frog muscles and cockroach thoracic ganglia and biochemical techniques were applied to membranes from Torpedo electric organ and honeybee brain. PhTX (1-20 microM) inhibited reversibly the indirectly elicited muscle twitch and reduced the endplate current peak amplitude and its decay time constant in a concentration-dependent manner. In patch clamp studies, PhTX (1-5 microM) when combined with acetylcholine, induced a concentration-dependent decrease in frequency of channel openings and in channel open and burst times. The cockroach fast coxal depressor neuron was inhibited by PhTX in a time- and voltage-dependent manner. The initial rate of binding of [3H]perhydrohistrionicotoxin to Torpedo nAChR in the presence of carbamylcholine was inhibited competitively by PhTX. Binding of alpha-[125I] bungarotoxin to electric organ and honeybee brain membranes was inhibited by PhTX. Binding of [3H]acetylcholine to the electric organ receptor was potentiated by low concentrations of PhTX but inhibited by high concentrations. PhTX, therefore, inhibits both vertebrate and insect nAChRs, which may be important molecular targets for its toxicity. It is suggested that PhTX at high concentration may have some competitive action on nAChR, but it acts mainly as a blocker of the ion channel of the nAChR in its open conformation.
ESTHER : Rozental_1989_J.Pharmacol.Exp.Ther_249_123
PubMedSearch : Rozental_1989_J.Pharmacol.Exp.Ther_249_123
PubMedID: 2468760