In the bio-based polymer industry, putrescine is in the spotlight for use as a material. We constructed strains of Escherichia coli to assess its putrescine production capabilities through the arginine decarboxylase pathway in batch fermentation. N-Acetylglutamate (ArgA) synthase is subjected to feedback inhibition by arginine. Therefore, the 19th amino acid residue, Tyr, of argA was substituted with Cys to desensitize the feedback inhibition of arginine, resulting in improved putrescine production. The inefficient initiation codon GTG of argA was substituted with the effective ATG codon, but its replacement did not affect putrescine production. The essential genes for the putrescine production pathway, speA and speB, were cloned into the same plasmid with argAATG Y19C to form an operon. These genes were introduced under different promoters; lacIp, lacIqp, lacIq1p, and T5p. Among these, the T5 promoter demonstrated the best putrescine production. In addition, disruption of the puuA gene encoding enzyme of the first step of putrescine degradation pathway increased the putrescine production. Of note, putrescine production was not affected by the disruption of patA, which encodes putrescine aminotransferase, the initial enzyme of another putrescine utilization pathway. We also report that the strain KT160, which has a genomic mutation of YifEQ100TAG, had the greatest putrescine production. At 48 h of batch fermentation, strain KT160 grown in terrific broth with 0.01 mM IPTG produced 19.8 mM of putrescine.
It is widely accepted that maternal separation (MS) induces stress in children and disrupts neural circuit formation during early brain development. Even though such disruption occurs transiently early in life, its influence persists after maturation, and could lead to various neurodevelopmental disorders. Our recent study revealed that repeated MS reduces the number of inhibitory neurons and synapses in the medial prefrontal cortex (mPFC) and causes mPFC-related social deficits after maturation. However, how MS impedes mPFC development during early brain development remains poorly understood. Here, we focused on brain-derived neurotrophic factor (BDNF) involved in the development of inhibitory neurons, and examined time-dependent BDNF expression in the mPFC during the pre-weaning period in male rats exposed to MS. Our results show that MS attenuates BDNF expression only around the end of the first postnatal week. Likewise, mRNA expression of activity-regulated cytoskeletonassociated protein (Arc), an immediate-early gene whose expression is partly regulated by BDNF, also decreased in the MS group along with the reduction in BDNF expression. On the contrary, mRNA expression of tropomyosinrelated kinase B (TrkB), which is a BDNF receptor, was scarcely altered, while its protein expression decreased in the MS group only during the weaning period. In addition, MS reduced mRNA levels of glutamic acid decarboxylase (GAD) 65, a GABA synthesizing enzyme, only during the weaning period. Our results suggest that repeated MS temporarily attenuates BDNF signaling in the mPFC during early brain development. BDNF plays a crucial role in the development of inhibitory neurons; therefore, transient attenuation of BDNF signaling may cause delays in GABAergic neuron development in the mPFC.
This paper explores situational factors and attitudes affecting sustainable electric kettle usage. We conducted a two-week long field study with five residents in Denmark who self-reported their electric kettle usage data, purpose of usage, and situations of usage, over the study period. A follow-up interview was also conducted after the field study to explore reasons behind the observed behaviors. Results show, the amount of excess water heated significantly varied by usage purpose as well as the time sensitivity of the usage purpose. There was no observable effect of the minimum fill level marker on the amount of excess water heated. Participants’ considerations for purchasing a specific kettle and their usage behaviors were not influenced by sustainability-related concerns. We identified four important factors that influenced the amount of excess water heated and participants’ decision to retain or dispose it. They included, (1) uncertainty in the need for hot water in the near future, (2) flexibility in the needed volume for a usage purpose, (3) forgetting to use heated water, and (4) concerns about limescale build up.
。また,ヒトで EYA1 が心奇形と関係してい Branchio-oto-renal (BOR) syndrome is a condition associated with branchiogenic anomalies, deafness, and renourinary anomalies as a symptomatic triad, and abnormality of the EYA1 is considered to be a causative factor. We encountered a 1-year-and-10-month-old girl with BOR syndrome complicated by cerebral cavernous malformation (CCM) exhibiting novel mutation of the EYA1. She was diagnosed with BOR syndrome as she showed bilateral cervical fistulas, bilateral deafness, and bilateral hydronephrosis/hydroureter at birth. Her mother had preauricular pits and deafness. The child suddenly developed afebrile tonic-clonic convulsion. MRI disclosed CCM in the right parietal lobe, and gene analysis demonstrated novel heteromutation in exon 13 of EYA1. We report this case since there is no published report of BOR syndrome accompanied by EYA1 mutation and complicated by CCM.
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