Seasonal variations in bacterioplankton community structures in two small rivers in the Himi region of central Japan and their relationships with environmental factors.

The aim of this study was to improve our understanding of seasonal variations and the effects of physicochemical conditions on the bacterioplankton communities in two small rivers, the Moo and Nakayachi Rivers in the Himi region of central Japan. These rivers are inhabited by unionid freshwater mussels, which are used for oviposition by the endangered Itasenpara bitterling (Acheilognathus longipinnis). Water samples were collected every month between March 2011 and February 2012. Changes in bacterioplankton community structures were analysed using an approach that did not require cultivating the bacteria and involved PCR and denaturing gradient gel electrophoresis. The bacterioplankton community structures in the two rivers were similar in all seasons except winter. The bacterial sequences identified were dominated by typical freshwater Actinobacteria, Bacteroidetes, Cyanobacteria, α-Proteobacteria, and ß-Proteobacteria bacterioplankton. Many ß-Proteobacteria species were detected in all seasons, but Bacteroidetes species were dominant in the winter. The bacterioplankton community structures were affected by biochemical oxygen demand, chemical oxygen demand, chlorophyll-a concentration, water depth, and water temperature. These results provide a foundation for a more detailed understanding of the conditions that provide a suitable unionid habitat.

Vitreous and aqueous penetration of orally and topically administered moxifloxacin.

AIM: It was the aim of this study to compare the pharmacokinetics of moxifloxacin (MFLX) hydrochloride in rabbits after topical and oral administration. METHODS: Three 50-µl applications of MFLX (0.5%) topical ophthalmic solution were instilled into the cul-de-sac of New Zealand white rabbits at 15-min intervals. Aqueous and vitreous samples were collected and analyzed 30-240 min after the final instillation. Assays were performed using high-performance liquid chromatography. MFLX (16 mg/kg of body weight) was administered orally. Drug concentrations in aqueous, vitreous and serum samples, collected at 30-360 min after administration, were determined using high-performance liquid chromatography. RESULTS: After topical administration, the maximum concentrations of MFLX in the aqueous and vitreous samples were 10.2 ± 1.6 µg/ml (30 min; n = 6) and 0.10 ± 0.03 µg/ml (30 min; n = 6), respectively. After oral administration, the maximum concentrations in the aqueous, vitreous and serum samples were 0.9 ± 0.3 µg/ml (120 min; n = 6), 0.7 ± 0.2 µg/ml (240 min; n = 6) and 1.6 ± 0.9 µg/ml (120 min; n = 6), respectively. The percentages of serum MFLX concentration in the aqueous and vitreous samples after oral administration were 55.2 and 41.7%, respectively. CONCLUSIONS: The aqueous concentration of MFLX was about 10-fold higher after topical than after oral administration. However, intravitreal MFLX concentrations after oral administration were about 7-fold higher than those after topical administration. The MFLX concentrations in the aqueous humor following oral administration exceeded the minimum inhibitory concentration for 90% of the bacteria involved in ocular infection.

Cyclin-dependent kinase inhibitor p16 and p21 expression, and cell cycle change in human lens epithelial cell line SRA 01/04 following contact inhibition in normal culture.

PURPOSE: To describe the pattern of expression of the cyclin-dependent kinase inhibitors (CDKIs) p16, p21 and p27, and the cell cycle in SRA 01/04 cells relative to contact inhibition. METHODS: SRA 01/04 cells were grown to overconfluence under normal conditions. At various phases of the cell growth, cells were assayed by flow cytometry and Western blotting for the expression of CDKIs. RESULTS: Expression of p16 was detected from early logarithmic growth to stationary phases, during which the number of cells in G(0)/G(1) increased from 46 to 69%. Expression of p21 was detected only during the overgrowth phase, when 60% of the cells were in G(0)/G(1). Expression of p27 was not observed in SRA 01/04 cells. CONCLUSIONS: p16 expression was likely mediated by G(0)/G(1) arrest to induce contact inhibition in SRA 01/04. p21 expression may be related to withdrawal, and p27 deficiency may be related to the immortality of this cell line. It is possible for p16 to stop proliferation of lens epithelial cells like progressing posterior capsular opacification, by overexpression to mimic contact inhibition.

Computational model for calculating body-core temperature elevation in rabbits due to whole-body exposure at 2.45 GHz.

In the current international guidelines and standards with regard to human exposure to electromagnetic waves, the basic restriction is defined in terms of the whole-body average-specific absorption rate. The rationale for the guidelines is that the characteristic pattern of thermoregulatory response is observed for the whole-body average SAR above a certain level. However, the relationship between energy absorption and temperature elevation was not well quantified. In this study, we improved our thermal computation model for rabbits, which was developed for localized exposure on eye, in order to investigate the body-core temperature elevation due to whole-body exposure at 2.45 GHz. The effect of anesthesia on the body-core temperature elevation was also discussed in comparison with measured results. For the whole-body average SAR of 3.0 W kg(-1), the body-core temperature in rabbits elevates with time, without becoming saturated. The administration of anesthesia suppressed body-core temperature elevation, which is attributed to the reduced basal metabolic rate.

Distribution of oil-degrading bacteria in coastal seawater, Toyama Bay, Japan.

Oil-degrading bacteria are considered to play an important role in the biodegradation of spilled or released oil in the sea. The distribution of indigenous oil-degrading bacteria in the coastal seawater of Toyama Bay, Japan, was examined. Surface seawater samples with or without oil film in fishing port were analyzed by denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified V3 region of bacterial 16S rDNA. Sequence analysis revealed that several DGGE bands clearly detected only in samples with oil film corresponded to Cyanobacteria. Moreover, we cultured surface seawater samples with oil film in two different liquid culture media, a marine broth and an NSW medium; each culture contained 0.5% (w/v) C-heavy oil. Emulsification of the oil was observed at day 6 in the marine broth and day 9 in the NSW medium. Time-dependent changes of bacterial communities in those culture media were analyzed by DGGE. Interestingly, we found that Alcanivorax sp. became one of the dominant bacteria in each culture medium when emulsification of the oil began. Alcanivorax sp. is one of the well-known oil-degrading bacteria in seawater and is associated with the production of biosurfactants. These results suggest that Cyanobacteria and Alcanivorax play important roles in the bioremediation of oil-contaminated areas in Toyama Bay.

[Intraocular penetration of cefotiam hydrochloride, a kind of cephalosporin after filtration surgery in rabbit eyes].

PURPOSE: In this study, we measured the cefotiam dihydrochloride (CTM) concentration in ocular tissue after filtration surgery in rabbit eyes. METHODS: CTM (20 mg/kg body weight) was administered intravenously 30 min before filtration surgery which was performed by double flap procedure on the right eyes of white rabbits. The aqueous humor and serum were extracted at 10 min after surgery and at 30 min, 60 min, and 120 min. Drug concentration in all of the specimens was measured by high performance liquid chromatography (HP-LC). RESULT: The CTM concentrations of aqueous humor in the nonoperated eyes were 0.44 +/- 0.16(mean +/- standard deviation) microg/ml (n = 4) (40 min after intravenous dosage), 0.36 +/- 0.17microg/ml (n = 4) (60 min after intravenous dosage), 0.38 +/- 0.34, microg/ml(n = 3) (90min after intravenous dosage) and 0.27 +/- 0.10 microg/ml (n = 5) (150 min after intravenous dosage). In contrast, CTM concentration in the aqueous humor of the operated eyes was 2.4 +/- 0.95 microg/ml (n = 4) at 10 min after surgery (40 min after intravenous dosage), 2.11 +/- 1.10 microg/ml (n = 4) at 30 min after surgery (60 min after intravenous dosage), 1.18 +/- 0.78 microg/ml (n = 4) at 60 min after surgery (90 min after intravenous dosage) and 0.47 +/- 0.1 microg/ml (n = 5) at 120 min after surgery (150 min after intravenous dosage). The intraocular penetration of CTM at 10 min and at 120 min after filtration surgery was significantly higher in comparison with the drug concentration in the nonoperated eyes (p < 0.05). CONCLUSION: The intraocular penetration of CTM after filtration surgery was much higher in comparison with the drug concentration in the nonoperated eyes. These results may be useful to predict the intraocular penetration of CTM in human eyes after filtration surgery.

A cold-adapted and organic solvent-tolerant lipase from a psychrotrophic bacterium Pseudomonas sp. strain YY31: identification, cloning, and characterization.

A novel cold-adapted lipase (designated as LipYY31) was obtained from a psychrotrophic Pseudomonas sp. YY31. The strain YY31 was gram-negative, rod shaped, motile by means of one polar flagellum, and exhibited chemotaxis toward oil droplets under a microscope. The strain displayed remarkable degradation of edible oil and fat even at 5 °C. The LipYY31 DNA fragment contains an open reading frame of 1,410 bp which encoded a protein of 470 amino acids with an estimated molecular mass of 49,584 Da. LipYY31 showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 25-30 °C, and it retained 20-40 % of its activity at 0-5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by Cd(2+), Zn(2+), EDTA and was highly dependent on Ca(2+). Tricaprin and p-nitrophenyl caprate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipYY31 also had high activity towards natural substrates including edible vegetable oils and animal fat. Furthermore, LipYY31 was very active and stable in the presence of several detergents and organic solvents. In particular, the lipase exhibited high stability against organic solvents such as methanol, ethanol, and isopropanol.

Characterization of a new cold-adapted lipase from Pseudomonas sp. TK-3.

A psychrotrophic Pseudomonas sp. TK-3 was isolated from dirty and cool stream water in Toyama, Japan from which we cloned and characterized the bacterial lipase LipTK-3. The sequenced DNA fragment contains an open reading frame of 1,428 bp that encoded a protein of 476 amino acids with an estimated molecular mass of 50,132 Da. The lipase showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 20-25 °C, lower than in most other subfamily Ι.3 lipases. The lipase exhibited about 30 % of maximal activity at 5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by EDTA and was highly dependent on Ca(2+). Tricaprylin and p-nitrophenyl caprylate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipTK-3 also showed high activity towards natural substrates including edible vegetable oils and animal fats. Furthermore, LipTK-3 was very active and stable in the presence of several detergents, metal ions, and organic solvents. This cold-adapted lipase may prove useful for future applications.

Acute dosimetry and estimation of threshold-inducing behavioral signs of thermal stress in rabbits at 2.45-GHz microwave exposure.

In the current international guidelines and standards for human exposure to microwaves (MWs), the basic restriction is determined by the whole-body average specific absorption rate (SAR). The basis for the guidelines is the adverse effect such as work stoppage in animals for whole-body average SARs above a certain level. Although it is known that absorbed MW energy causes the behavioral sign of thermal stress, the relationship of whole-body average SAR with temperature/temperature elevation has not been sufficiently investigated. In the present study, we performed experiments on rabbits exposed to 2.45-GHz MWs. A total of 24 measurements were conducted for power densities from approximately 100 to 1000 W/m(2). Our computational code for electromagnetic-thermal dosimetry was used to set the exposure time duration and incident power density. Our experimental results suggest that a core temperature elevation of 1 degrees C is an estimate of the threshold-inducing complex behavioral signs of MW-induced thermal stress in rabbits for different whole-body average SARs and exposure time durations. The whole-body average SAR required for MW-induced behavioral sign in rabbits was estimated as approximately 1.3 W/kg for 2.45-GHz MWs.

Acute ocular injuries caused by 60-Ghz millimeter-wave exposure.

The goal of this study was to examine the clinical course of 60-GHz millimeter-wave induced damages to the rabbit eye and to report experimental conditions that allow reproducible induction of these injuries. The eyes of pigmented rabbits (total number was 40) were irradiated with 60-GHz millimeter-waves using either a horn antenna or one of two lens antennas (6 and 9 mm diameter; phi6, phi9) Morphological changes were assessed by slit-lamp microscopy. Additional assessments included corneal fluorescein staining, iris fluorescein angiography, and lens epithelium light microscopy. Under the standardized eye-antenna positioning, the three antennas caused varying damages to the eyelids or eyeglobes. The most reproducible injuries without concurrent eyelid edema and corneal desiccation were achieved using the phi6 lens antenna: irradiation for 6 min led to an elevation of the corneal surface temperature (reaching 54.2 +/- 0.9 degrees C) plus corneal edema and epithelial cell loss. Furthermore, mitotic cells appeared in the pupillary area of the lens epithelium. Anterior uveitis also occurred resulting in acute miosis (from 6.6 +/- 1.4 to 2.2 +/- 1.4 mm), an increase in flares (from 6.7 +/- 0.9 to 334.3 +/- 130.8 photons per second), and iris vasodilation or vessel leakage. These findings indicate that the three types of millimeter-wave antennas can cause thermal injuries of varying types and levels. The thermal effects induced by millimeter-waves can apparently penetrate below the surface of the eye.