Characterization of bacterial-type phosphoenolpyruvate carboxylase expressed in male gametophyte of higher plants

<p>Abstract</p> <p>Background</p> <p>Phospho<it>enol</it>pyruvate carboxylase (PEPC) is a critical enzyme catalyzing the β-carboxylation of phospho<it>enol</it>pyruvate (PEP) to oxaloacetate, a tricarboxylic acid (TCA) cycle intermediate. PEPC typically exists as a Class-1 PEPC homotetramer composed of plant-type PEPC (PTPC) polypeptides, and two of the subunits were reported to be monoubiquitinated in germinating castor oil seeds. By the large-scale purification of ubiquitin (Ub)-related proteins from lily anther, two types of PEPCs, bacterial-type PEPC (BTPC) and plant-type PEPC (PTPC), were identified in our study as candidate Ub-related proteins. Until now, there has been no information about the properties of the PEPCs expressed in male reproductive tissues of higher plants.</p> <p>Results</p> <p>Expression analyses showed that lily BTPC (LlBTPC) and <it>Arabidopsis </it>BTPC (AtBTPC) were significantly expressed in pollen. The fusion protein AtBTPC-Venus localized in the cytoplasm of the vegetative cell (VC). Both LlBTPC and AtBTPC expression initiated after the last mitosis before pollen germination. Lily PTPC (LlPTPC) and monoubiquitinated LlPTPC (Ub-LlPTPC) remained at constant levels during pollen development. In late bicellular pollen of lily, LlBTPC forms a hetero-octameric Class-2 PEPC complex with LlPTPC to express PEPC activity.</p> <p>Conclusion</p> <p>Our results suggest that an LlBTPC:Ub-LlPTPC:LlPTPC complex is formed in the VC cytoplasm during late pollen development. Both LlBTPC and AtBTPC expression patterns are similar to the patterns of the appearance of storage organelles during pollen development in lily and <it>Arabidopsis</it>, respectively. Therefore, BTPC is thought to accelerate the metabolic flow for the synthesis of storage substances during pollen maturation. Our study provides the first characterization of BTPC in pollen, the male gametophyte of higher plants.</p

Characteristic expression of twelve rice PR1 family genes in response to pathogen infection, wounding, and defense-related signal compounds (121/180)

Pathogenesis-related (PR) proteins have been used as markers of plant defense responses, and are classified into 17 families. However, precise information on the majority members in specific PR families is still limited. We were interested in the individual characteristics of rice PR1 family genes, and selected 12 putatively active genes using rice genome databases for expressed genes. All were upregulated upon compatible and/or incompatible rice-blast fungus interactions; three were upregulated in the early infection period and four in the late infection period. Upon compatible rice–bacterial blight interaction, four genes were upregulated, six were not affected, and one was downregulated. These results are in striking contrast to those among 22 ArabidopsisPR1 genes where only one gene was pathogen-inducible. The responses of individual genes to salicylic acid, jasmonic acid, and ethylene induced defense signaling pathways in rice are likely to be different from those in dicot plants. Transcript levels in healthy leaves, roots, and flowers varied according to each gene. Analysis of the partially overlapping expression patterns of rice PR1 genes in healthy tissues and in response to pathogens and other stresses would be useful to understand their possible functions and for use as characteristic markers for defense-related studies in rice

Evolutionary adaptation of visual pigments in geckos for their photic environment

家の守り神「ヤモリ」が夜でも色を見分けられるのはなぜ --ヤモリが持つ特殊な色覚能力の分子メカニズムを解明--. 京都大学プレスリリース. 2021-10-04.Vertebrates generally have a single type of rod for scotopic vision and multiple types of cones for photopic vision. Noteworthily, nocturnal geckos transmuted ancestral photoreceptor cells into rods containing not rhodopsin but cone pigments, and, subsequently, diurnal geckos retransmuted these rods into cones containing cone pigments. High sensitivity of scotopic vision is underlain by the rod’s low background noise, which originated from a much lower spontaneous activation rate of rhodopsin than of cone pigments. Here, we revealed that nocturnal gecko cone pigments decreased their spontaneous activation rates to mimic rhodopsin, whereas diurnal gecko cone pigments recovered high rates similar to those of typical cone pigments. We also identified amino acid residues responsible for the alterations of the spontaneous activation rates. Therefore, we concluded that the switch between diurnality and nocturnality in geckos required not only morphological transmutation of photoreceptors but also adjustment of the spontaneous activation rates of visual pigments

Research ethics consultation : an attempt and 5-year experience in a Japanese University Hospital

Objective: Research ethics consultation is an advisory activity that differs from ethics committees, and its role is not yet widely known in Japan. Research ethics consultations were started in 2012 by members of the Clinical Trial Center of Tokushima University Hospital, a support section for clinical trials. We analyzed the research ethics consultation records from Tokushima University Hospital during the 5-year period of 2012–2016 to examine the Japanese context of research ethics consultation. Results: During the study period, 125 research ethics consultations were carried out, 115 (91%) before starting studies. All but one request were from investigators at Tokushima University. The main issue was compatibility with guidance and regulations (n = 74, 67.2%), such as ethical handling of human biological specimens and information utilized in research; only 6 (4.8%) requests involved research ethics issues that investigators face in their research. Therefore, it is necessary to expand the consultation function, with a nationwide system of consultant education and data sharing. Moreover, standardization of consultation should be considered

Pure Red Cell Aplasia Induced by Atezolizumab in a Patient with Small-Cell Lung Cancer Successfully Treated with Steroid Therapy: A Case Report

Introduction: Combination therapy of atezolizumab and chemotherapy has become the standard treatment for small-cell lung cancer. Immune-related adverse events (irAEs) can occur during immune checkpoint inhibitor administration. A few reports exist on pure red cell aplasia (PRCA) as an irAE after atezolizumab treatment. PRCA is characterized by normocytic-normochromic anemia, a marked decrease in reticulocytes, and a decrease in bone marrow erythroblasts. Here, we report a case of atezolizumab-induced PRCA. Case Presentation: A 69-year-old male patient was brought to the emergency department with the chief complaint of seizures. Multiple metastatic brain tumors and a mass suspected to be the primary lesion in the right hilar region were observed. After a brain biopsy, he was diagnosed with small-cell lung cancer (cT1cN0M1c stage IVB). He received four courses of carboplatin, etoposide, and atezolizumab in combination with whole-brain irradiation, which led to a partial response. After six courses of atezolizumab maintenance therapy, severe anemia (hemoglobin, 3.4 g/dL) was observed. PRCA induced by atezolizumab was diagnosed using a bone marrow biopsy performed during red blood cell transfusion. Treatment was started with prednisolone 25 mg/day (0.5 mg/kg/day). Anemia improved, and the dose was gradually reduced to 5 mg/day. Conclusion: Reports of PRCA as an irAE are rare but important; hence, we reported this case

Monoamines Inhibit GABAergic Neurons in Ventrolateral Preoptic Area That Make Direct Synaptic Connections to Hypothalamic Arousal Neurons

The hypothalamus plays an important role in the regulation of sleep/wakefulness states. While the ventrolateral preoptic nucleus (VLPO) plays a critical role in the initiation and maintenance of sleep, the lateral posterior part of the hypothalamus contains neuronal populations implicated in maintenance of arousal, including orexin-producing neurons (orexin neurons) in the lateral hypothalamic area (LHA) and histaminergic neurons in the tuberomammillary nucleus (TMN). During a search for neurons that make direct synaptic contact with histidine decarboxylase-positive (HDC+), histaminergic neurons (HDC neurons) in the TMN and orexin neurons in the LHA of male mice, we found that these arousal-related neurons are heavily innervated by GABAergic neurons in the preoptic area including the VLPO. We further characterized GABAergic neurons electrophysiologically in the VLPO (GABAVLPO neurons) that make direct synaptic contact with these hypothalamic arousal-related neurons. These neurons (GABAVLPO→HDC or GABAVLPO→orexin neurons) were both potently inhibited by noradrenaline and serotonin, showing typical electrophysiological characteristics of sleep-promoting neurons in the VLPO. This work provides direct evidence of monosynaptic connectivity between GABAVLPO neurons and hypothalamic arousal neurons and identifies the effects of monoamines on these neuronal pathways

Isolation and identification of ubiquitin-related proteins from Arabidopsis seedlings

The majority of proteins in eukaryotic cells are modified according to highly regulated mechanisms to fulfill specific functions and to achieve localization, stability, and transport. Protein ubiquitination is one of the major post-translational modifications occurring in eukaryotic cells. To obtain the proteomic dataset related to the ubiquitin (Ub)-dependent regulatory system in Arabidopsis, affinity purification with an anti-Ub antibody under native condition was performed. Using MS/MS analysis, 196 distinct proteins represented by 251 distinct genes were identified. The identified proteins were involved in metabolism (23.0%), stress response (21.4%), translation (16.8%), transport (6.7%), cell morphology (3.6%), and signal transduction (1.5%), in addition to proteolysis (16.8%) to which proteasome subunits (14.3%) is included. On the basis of potential ubiquitination-targeting signal motifs, in-gel mobilities, and previous reports, 78 of the identified proteins were classified as ubiquitinated proteins and the rest were speculated to be associated proteins of ubiquitinated proteins. The degradation of three proteins predicted to be ubiquitinated proteins was inhibited by a proteasome inhibitor, suggesting that the proteins were regulated by Ub/proteasome-dependent proteolysis

Nephrotoxicity with VCM and Nephrotoxins

There is a growing concern about the relationship between vancomycin-associated nephrotoxicity (VAN) and concomitant use of nephrotoxins. We examined this relationship by combined retrospective analyses of two real-world databases. Initially, the FDA Adverse Event Reporting System (FAERS) was analyzed for the effects of concomitant use of one or more nephrotoxins on VAN and the types of combinations of nephrotoxins that exacerbate VAN. Next, electronic medical records (EMRs) of patients who received vancomycin (VCM) at Tokushima University Hospital between January 2006 and March 2019 were examined to confirm the FAERS analysis. An elevated reporting odds ratio (ROR) was observed with increases in the number of nephrotoxins administered (VCM + one nephrotoxin, adjusted ROR (95% confidence interval [CI]) 1.67 [1.51–1.85]; VCM + ≥ 2 nephrotoxins, adjusted ROR [95% CI] 1.54 [1.37–1.73]) in FAERS. EMRs analysis showed that the number of nephrotoxins was associated with higher incidences of VAN [odds ratio: 1.99; 95% CI: 1.42–2.78]. Overall, concomitant use of nephrotoxins was associated with an increased incidence of VAN, especially when at least one of those nephrotoxins was a renal hypoperfusion medication (furosemide, non-steroidal anti-inflammatory drugs, and vasopressors). The concomitant use of multiple nephrotoxins, especially including renal hypoperfusion medication, should be avoided to prevent VAN

Concomitant Use of Multiple Nephrotoxins including Renal Hypoperfusion Medications Causes Vancomycin-Associated Nephrotoxicity: Combined Retrospective Analyses of Two Real-World Databases

There is a growing concern about the relationship between vancomycin-associated nephrotoxicity (VAN) and concomitant use of nephrotoxins. We examined this relationship by combined retrospective analyses of two real-world databases. Initially, the FDA Adverse Event Reporting System (FAERS) was analyzed for the effects of concomitant use of one or more nephrotoxins on VAN and the types of combinations of nephrotoxins that exacerbate VAN. Next, electronic medical records (EMRs) of patients who received vancomycin (VCM) at Tokushima University Hospital between January 2006 and March 2019 were examined to confirm the FAERS analysis. An elevated reporting odds ratio (ROR) was observed with increases in the number of nephrotoxins administered (VCM + one nephrotoxin, adjusted ROR (95% confidence interval [CI]) 1.67 [1.51-1.85]; VCM + ≥2 nephrotoxins, adjusted ROR [95% CI] 1.54 [1.37-1.73]) in FAERS. EMRs analysis showed that the number of nephrotoxins was associated with higher incidences of VAN [odds ratio: 1.99; 95% CI: 1.42-2.78]. Overall, concomitant use of nephrotoxins was associated with an increased incidence of VAN, especially when at least one of those nephrotoxins was a renal hypoperfusion medication (furosemide, non-steroidal anti-inflammatory drugs, and vasopressors). The concomitant use of multiple nephrotoxins, especially including renal hypoperfusion medication, should be avoided to prevent VAN