Dissecting polyunsaturated fatty acid synthases for product profile control

Polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) are essential fatty acids for humans and are ingested from fish oils. Because of increasing demand, however, fermentative processes using microalgae, yeasts, and fungi have been developed to produce DHA, EPA, and ARA, respectively. PUFAs are biosynthesized by either desaturases/elongases from oleic acid or PUFA synthases from acetyl units. PUFA synthases are composed of three to four subunits and each create a specific PUFA without undesirable byproducts even though the multiple catalytic domains in each huge subunit are very similar. In this study, we carefully dissected these PUFA synthases by in vivo and in vitro experiments and elucidated how the enzymes control PUFA profiles (Figure 1) 1). Moreover, for the first time, we converted a practical microalgal DHA synthase into an EPA synthase based on the obtained results 2). Please click Additional Files below to see the full abstract

Transarterial embolization for convexity dural arteriovenous fistula

Background: Convexity dural arteriovenous fistulae (dAVF) usually reflux into cortical veins without involving the venous sinuses. Although direct drainage ligation is curative, transarterial embolization (TAE) may be an alternative treatment. Case Description: Between September 2018 and January 2021, we encountered four patients with convexity dAVFs. They were three males and one female; their age ranged from 36 to 73 years. The initial symptom was headache (n = 1) or seizure (n = 2); one patient was asymptomatic. In all patients, the feeders were external carotid arteries with drainage into the cortical veins; in two patients, there was pial arterial supply from the middle cerebral artery. All patients were successfully treated by TAE alone using either Onyx or N-butyl cyanoacrylate embolization. Two patients required two sessions. All dAVFs were completely occluded and follow-up MRI or angiograms confirmed no recurrence. Conclusion: Our small series suggests that TAE with a liquid embolic material is an appropriate first-line treatment in patients with convexity dAVFs with or without pial arterial supply

Functional Analyses of MMPs for Aragonite Crystal Formation in the Ligament of Pinctada fucata

The mollusk class, Bivalvia, plays an important role in the formation of calcium carbonate in the ocean. The bivalve hinge ligament is a hard but pliant tissue that resists the stress placed on the hinge during opening and closing. The ligament comprises a fine microstructure of fibrous aragonite crystals surrounded by a dense organic matrix. The matrix consists of organic fibers that are aligned with the fibrous aragonite crystals. Previous studies identified a tissue inhibitor of metalloproteinase (Pf-TIMP: Pinctada fucata-Tissue Inhibitor of Metalloproteinase) in the organic fibers of P. fucata ligaments. This enzyme exhibited strong inhibition of matrix metalloproteinase (MMP) activity in vitro, suggesting that MMPs also play a role in formation of the organic fibers of the ligament. Using transcriptome data, we identified MMP genes from the mantle isthmus, which is a soft tissue attached to the ligament. To investigate the function of MMP genes in vivo, we performed RNA interference experiments. The expression of MMP14973 and MMP07860 genes was inhibited after injection of each dsRNA. Cumulative injection of MMP07860 dsRNA induced aggregated aragonite fiber orientation, whereas the injection of MMP14973 showed minor effects. When the decalcified ligament was incubated in a solution saturated with calcium carbonate, aragonite fibers aligned along the surface. When the decalcified ligament was treated with recombinant human (hr) MMP-13, the precipitation of calcium carbonate was inhibited. To investigate general MMP functions in calcium carbonate crystallization in detail, we precipitated aragonite crystals in collagen gels treated with or without recombinant human (hr) MMP-1. Treatment with hrMMP-1 increased the interaction between collagen gels and calcium carbonate. These results imply that Pinctada fucata (Pf)-MMPs degrade extracellular matrices in the ligament to produce the fine organic fibers that regulate the orientation of fibrous aragonite crystals

Individual Radiation Exposure Dose Due to Support Activities at Safe Shelters in Fukushima Prefecture

Immediately after the accidents in the nuclear power stations in Fukushima on March 11, the Japanese Government ordered the evacuation of the residents within a 20-km radius from the station on March 12, and asked various institutions to monitor the contamination levels of the residents. Hirosaki University, which is located 355 km north of Fukushima City, decided to send support staff to Fukushima. This report summarizes the results of the exposure of 13 individual teams from March 15 to June 20. The support teams surveyed more than 5,000 people during this period. Almost all subjects had external contamination levels of less than 13 kcpm on Geiger-Müller (GM) survey meter, which is categorized as “no contamination level.” The 1st team showed the highest external exposure dose, but the 4th team onward showed no significant change. Subsequently, the internal radiation exposure was measured using a whole body counter that indicated undetectable levels in all staff members. Although the measured external radiation exposure dose cannot have serious biological effects on the health of an individual, a follow-up study of the residents in Fukushima and other regions where the radioactive material has spread will be required for a long time

Role of the Carboxy-Terminal Region of the GluRε2 Subunit in Synaptic Localization of the NMDA Receptor Channel

AbstractThe synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain. We generated mutant mice carrying the carboxy-terminal truncated GluRε2 subunit of the NMDA receptor channel. The mutant mice died neonatally and failed to form barrelette structures in the brainstem. The mutation greatly decreased the NMDA receptor–mediated component of hippocampal excitatory postsynaptic potentials and punctate immunofluorescent labelings of GluRε2 protein in the neuropil regions, while GluRε2 protein expression was comparable. Immunostaining of cultured cerebral neurons showed the reduced punctate staining of the truncated GluRε2 protein at synapses. These results suggest that the carboxy-terminal region of the GluRε2 subunit is important for efficient clustering and synaptic localization of the NMDA receptor channel

Localized Brain Activation Related to the Strength of Auditory Learning in a Parrot

Parrots and songbirds learn their vocalizations from a conspecific tutor, much like human infants acquire spoken language. Parrots can learn human words and it has been suggested that they can use them to communicate with humans. The caudomedial pallium in the parrot brain is homologous with that of songbirds, and analogous to the human auditory association cortex, involved in speech processing. Here we investigated neuronal activation, measured as expression of the protein product of the immediate early gene ZENK, in relation to auditory learning in the budgerigar (Melopsittacus undulatus), a parrot. Budgerigar males successfully learned to discriminate two Japanese words spoken by another male conspecific. Re-exposure to the two discriminanda led to increased neuronal activation in the caudomedial pallium, but not in the hippocampus, compared to untrained birds that were exposed to the same words, or were not exposed to words. Neuronal activation in the caudomedial pallium of the experimental birds was correlated significantly and positively with the percentage of correct responses in the discrimination task. These results suggest that in a parrot, the caudomedial pallium is involved in auditory learning. Thus, in parrots, songbirds and humans, analogous brain regions may contain the neural substrate for auditory learning and memory