evaluation-fertilization-state-tracing-sperm-nuclear-morphology

Evaluation of Fertilization State by Tracing Sperm Nuclear Morphology in <em>Arabidopsis</em> Double Fertilization

Flowering plants have a unique sexual reproduction system called &#8216;double fertilization&#39;,&#160;in which each of the sperm cells precisely fuses ...

chiba university

Non-motor symptoms (e.g., depression, anxiety, and cognitive deficits) in patients with Parkinson disease (PD) precede the onset of the motor symptoms. Although these symptoms do not respond to pharmacological dopamine replacement therapy, their precise pathological mechanisms are currently unclear. The present study was undertaken to examine whether the unilateral 6-hydroxydopamine (6-OHDA) lesion to the substantia nigra pars compacta (SNc), which represents a model of long-term dopaminergic neurotoxicity, could affect cell proliferation in the adult rat brain. Furthermore, we examined the effects of the selective serotonin reuptake inhibitor (SSRI) fluoxetine and the selective noradrenaline reuptake inhibitor maprotiline on the reduction in cell proliferation in the subgranular zone (SGZ) by the unilateral 6-OHDA lesion.

Destruction of dopaminergic neurons in the midbrain by 6-hydroxydopamine decreases hippocampal cell proliferation in rats: reversal by fluoxetine.

Accumulating evidence suggests that dysfunction in the glutamatergic system may underlie the pathophysiology of autism. The anterior cingulate cortex (ACC) has been implicated in autism as well as in glutamatergic neurotransmission. We hypothesized that alterations in the glutamate-glutamine cycle in the ACC might play a role in the pathophysiology of autism.

Enzymes in the glutamate-glutamine cycle in the anterior cingulate cortex in postmortem brain of subjects with autism.

KEY MESSAGE : hap2-1 pollen tube ovule targeting. Upon pollination, a pollen grain germinates to produce a pollen tube, which grows through the style to deliver two immobile sperm cells to the female gametophyte. Double fertilization is completed after the pollen tube enters an ovule. GENERATIVE CELL SPECIFIC 1 (GCS1)/HAPLESS 2 (HAP2) contributes to the fusion of gametes at fertilization and has been suggested to affect pollen tube guidance. However, there is controversy over the role of GCS1/HAP2 in pollen tube guidance because of conflicting results from different studies. To characterize the effects of the gcs1/hap2 mutation on pollen tube behavior, we analyzed the Arabidopsis thaliana hap2-1/HAP2 mutant, which carries a gcs1/hap2 mutation in the quartet background. The quartet mutant produces tetrads consisting of four pollen grains that remain adherent after the pollen mother cell has completed meiosis. Thus, a hap2-1/HAP2 tetrad contains hap2-1 and HAP2 pollen grains in a 2:2 ratio. Moreover, the hap2-1 locus is linked to the β-glucuronidase (GUS) gene. An excess pollination experiment with hap2-1/HAP2 tetrads revealed that the hap2-1 pollen tube targets ovules normally. Additionally, the results of restricted pollination and aniline blue staining indicated that there are no significant differences between the ovule-targeting frequencies of pollen tubes from hap2-1/HAP2 and HAP2/HAP2 tetrads.

Loss of GCS1/HAP2 does not affect the ovule-targeting behavior of pollen tubes.

All flowering plants exhibit a unique type of sexual reproduction called 'double fertilization' in which each pollen tube-delivered sperm cell fuses with an egg and a central cell. Proteins that localize to the plasma membrane of gametes regulate one-to-one gamete pairing and fusion between male and female gametes for successful double fertilization. Here, we have identified a membrane protein from  generative cells using proteomic analysis and have found that the protein is an ortholog of  DUF679 DOMAIN MEMBRANE PROTEIN 9 (DMP9)/DUO1-ACTIVATED UNKNOWN 2 (DAU2). The flowering plant DMP9 proteins analyzed in this study were predicted to have four transmembrane domains and be specifically expressed in both generative and sperm cells. Knockdown of  resulted in aborted seeds due to single fertilization of the central cell. Detailed imaging of -knockdown sperm cells during  and semi- double fertilization revealed that DMP9 is involved in gamete interaction that leads to correct double fertilization.

Article	Year
Destruction of dopaminergic neurons in the midbrain by 6-hydroxydopamine decreases hippocampal cell proliferation in rats: reversal by fluoxetine. PloS one\| PubMed ID: 20174647	2010
Enzymes in the glutamate-glutamine cycle in the anterior cingulate cortex in postmortem brain of subjects with autism. Molecular autism\| PubMed ID: 23531457	2013
Loss of GCS1/HAP2 does not affect the ovule-targeting behavior of pollen tubes. Plant reproduction\| PubMed ID: 28791484	2017
The male gamete membrane protein DMP9/DAU2 is required for double fertilization in flowering plants. Development (Cambridge, England)\| PubMed ID: 30487178	2018

Taro Takahashi

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