Vertical distribution of Microcystis population in the regulated Nakdong River, Korea

The vertical distribution of a bloom-forming Microcystis population was studied based on the relevant limnological parameters obtained from the lower Nakdong River (Mulgum) during the summer of 1994. Over three months (late June to late September), a high abundance of Microcystis population (mean ± SD, 2.9 ± 8.4 × 10⁵ cells ml⁻¹, n = 40) and algal biomass (mean ± SD, chlorophyll a, 131 ± 346 μg l⁻¹, n = 31) was persistent throughout the entire water column (0–5 m, n = 11). The vertical distribution of carbon content was uneven, with a high concentration near the surface zone (mean ± SD, total, 7.9 ± 7.8; Microcystis, 5.2 ± 8.3 μg C ml⁻¹, n = 15). Incorporating limnological and meteorological factors, a diel study of the vertical distribution of Microcystis showed that the chlorophyll a concentration was highest near the surface zone on a calm night (wind velocity, <2 m s⁻¹, 2300–700) but was evenly distributed on a windy day (>4 m s⁻¹, 1100–1900). Among many possible factors, wind velocity may have played an important role in controlling the vertical distribution of Microcystis in the lower Nakdong River. Received: July 12, 1999 / Accepted: November 15, 1999     

Effect of dietary Platycodon grandiflorum on the improvement of insulin resistance in obese Zucker rats

The effect of dietary Platycodon grandiflorum on the improvement of insulin resistance and lipid profile was investigated in lean (Fa/-) and obese (fa/fa) Zucker rats, a model for noninsulin dependent diabetes mellitus. Dietary Platycodon grandiflorum feeding for 4 weeks resulted in a significant decrease in the concentration of plasma triglyceride in both lean and obese Zucker rats. Furthermore, dietary Platycodon grandiflorum markedly decreased both plasma cholesterol and fasting plasma insulin levels, and significantly decreased the postprandial glucose level at 30 min during oral glucose tolerance test in obese Zucker rats. Although there was no statistical significance, the crude glucose transporter 4 protein level of obese rats fed Platycodon grandiflorum tended to increase when compared with that of obese control rats. Therefore, the present results suggested that dietary Platycodon grandiflorum may be useful in prevention and improvement of metabolic disorders characterized by hyperinsulinemia states such as noninsulin dependent diabetes mellitus, syndrome X, and coronary artery disease.     

The distribution and requirements of microtubules and microfilaments in bovine oocytes during in vitro maturation

Microtubules and microfilaments are major cytoskeletal components and important modulators for chromosomal movement and cellular division in mammalian oocytes. In this study we observed microtubule and microfilament organisation in bovine oocytes by laser scanning confocal microscopy, and determined requirements of their assembly during in vitro maturation. After germinal vesicle breakdown, small microtubular asters were observed near the condensed chromatin. The asters appeared to elongate and encompass condensed chromatin particles. At the metaphase stage, microtubules were observed in the second meiotic spindle at the metaphase stage. The meiotic spindle was a symmetrical, barrel-shaped structure containing anastral broad poles, located peripherally and radially oriented. Treatment with nocodazole did not inhibit germinal vesicle breakdown. However, progression to metaphase failed to occur in oocytes treated with nocodazole. In contrast, microfilaments were observed as a relatively thick uniform area around the cell cortex and overlying chromatin following germinal vesicle breakdown. Treatment with cytochalasin B inhibited microfilament polymerisation but did not prevent either germinal vesicle breakdown or metaphase formation. However, movement of chromatin to the proper position was inhibited in oocytes treated with cytochalasin B. These results suggest that both microtubules and microfilaments are closely associated with reconstruction and proper positioning of chromatin during meiotic maturation in bovine oocytes.     

A case of chronic cerebral paragonimiasis westermani

We report a chronic cerebral paragonimiasis from a 41-year-old Korean man who complains a headache and weakness of left motor neuron components. Magnetic resonance images of the brain revealed conglomerates of multiple ring-like enhancements in temporo-occipital and frontal lobes of the right hemisphere. An intradermal test for paragonimiasis westermani was positive. The patient was born near an endemic area of paragonimiasis and used to eat boiled or grilled freshwater crayfish in his childhood. Nodules in the brain were resected through craniotomies. The eggs of P. westermani were identified pathologically and parasitologically in the calcified necrotic lesions. Examinations on sputum and fecal specimens for the eggs of P. westermani were shown to be negative and a chest radiograph was normal. It is presumed that the brain lesions were formed by P. westermani approximately 30 years ago.     

Development of polymorphic microsatellite markers for the Trichoglossus haematodus and cross-species amplification in Trichoglossus moluccanus

Molecular Biology Reports - Trichoglossus haematodus is the most popular parrots globally and one of the most bred species in Korea's zoos. However, despite its popularity, there are limited...     

New records of two deep-sea eels collected from the Western Pacific Ocean based on COI and 16S rRNA genes

Background

Two deep-sea eels collected from the Western Pacific Ocean are described in this study. Based on their morphological characteristics, the two deep-sea eel specimens were assumed to belong to the cusk-eel family Ophidiidae and the cutthroat eel family Synaphobranchidae.

Methods and results

To accurately identify the species of the deep-sea eel specimens, we sequenced the mitochondrial genes (cytochrome c oxidase subunit I [COI] and 16S ribosomal RNA [16S rRNA]). Through molecular phylogenetic analysis based on mtDNA COI and 16S rRNA gene sequences, these species clustered with the genera Bassozetus and Synaphobranchus, suggesting that the deep-sea eel specimens collected are two species from the genera Bassozetus and Synaphobranchus in the Western Pacific Ocean, respectively.

Conclusions

This is the first study to report new records of the genera Bassozetus and Synaphobranchus from the Western Pacific Ocean based on COI and 16S rRNA genes

     

<Emphasis Type="Italic">In vitro</Emphasis> anti-inflammatory efficacies of liposomal suspensions of acetylsalicylic acid

Egg phosphatidylcholine (EPC) liposome containing acetylsalicylic acid (ASA) (EPC/ASA liposome) was prepared by a film hydration and sonication method, and the effect of liposome on the in vitro anti-inflammatory efficacy and the in vitro skin permeation of ASA was investigated. The mean diameter of EPC liposome and EPC/ASA liposome was about 271 and 175 nm, respectively. Both of liposomes were multi-lamellar vesicles on transmission electron microscopy photos. The in vitro viability of cell (Raw264.7) treated with EPC/ASA liposome suspension was significantly lower than the viability of cell treated with ASA solution. The amount of nitrite and prostaglandin E2 produced by cell treated with EPC/ASA liposome suspension was significantly lower than the amount produced by cells treated with ASA solution, indicating EPC liposome boosted the anti-inflammatory efficacy of ASA. The amount of ASA permeated through hairless mouse skin was inappreciable for 24 h when ASA solution was applied, whereas the permeation amount markedly increased to about 185 μg/cm² for 24 h when EPC/ASA liposome suspension was applied. EPC liposome also enhanced the permeation into stratum corneum and epidermis/dermis.