Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation-based approach.

The free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size-exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC + PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254 nm (SUVA(254) ), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH + THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH + THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high-sensitivity cultivation-based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters.

Effective isolation of bacterioplankton genus Polynucleobacter from freshwater environments grown on photochemically degraded dissolved organic matter.

Effective isolation of freshwater bacterioplankton belonging to genus Polynucleobacter from a shallow eutrophic lake and its tributary was achieved by size-selective filtration with a 0.7-mum pore filter and cultivation on R2A agar medium. Partial 16S rRNA gene analysis showed that over 80% of all the strains were highly similar to the Polynucleobacter cluster. Essential medium components for effective cultivation are pyruvate, yeast extract and peptone, whereas soluble starch and glucose are not necessary. Isolate KF001 (affiliated with Polynucleobacter subcluster D) has a strict requirement for organic acids as carbon sources, and we hypothesize that the Polynucleobacter cluster of bacteria could utilize compounds formed via photochemically dissolved organic matter (DOM) degradation for growth. Because organic acids form from solar radiation of DOM in aquatic environments, carbon sources that are typical products of DOM photochemical degradation were added to the medium. These compounds were readily utilized by KF001 in this study. Finally, we observed the stimulation of strain KF001 activity by photochemical degradation of natural lake water. Our findings suggest a carbon flow of DOM photoproducts to Polynucleobacter in the freshwater microbial loop.

[Epidemiological survey of pneumococcus serotypes in pediatric patients with acute suppurative otitis media].

To determine the distribution of Streptococcus pneumoniae serotypes isolated from patients under 6 years of age with acute suppurative otitis media, to calculate the serotype coverage of 7-valent pneumococcal conjugate vaccine, and to clarify trends in PCG-resistant Streptococcus pneumoniae, we conducted a one-year prospective study from April 2005 to March 2006 at 10 medical institutions in Hokkaido, Miyagi, Chiba, Tokyo, Kanagawa, and Mie, Japan. Specimens collected by tympanotomy or myringotomy numbered 856, and 691 strains were isolated from 599 specimens. Of these, 219 isolates (31.7%) were identified as Streptococcus pneumoniae and 201 met study requirements. The most common serotype was 19F (52 isolates, 25.9%), followed by 6B (30 isolates, 14.9%) and 23F (24 isolates, 11.9%). Seven-valent vaccine serotype coverage was 62.7%. The percentage of PSSP was 40.3%, PISP 42.8%, and PRSP 16.9%, resistant strains (PISP and PRSP) combined accounted for 59.7%. Seven-valent vaccine serotype coverage for PISP was 80.2% and PRSP 82.4%. PBP gene mutation was observed in 175 isolates (87.1%), including 70 of gPISP (34.8%) and 105 of gPRSP (52.2%). Gene mutation induced by macrolides was found in 176 isolates (87.6%).

The topical penta-peptide Gly-Pro-Ile-Gly-Ser increases the proportion of thick hair in Japanese men with androgenetic alopecia.

BACKGROUND: A penta-peptide, Gly-Pro-Ile-Gly-Ser (GPIGS), promotes proliferation of mouse hair keratinocytes and accelerates hair growth in mice. AIM OF THIS STUDY: This study focused on the ability of the peptide to promote human hair growth. METHODS: We used a human hair keratinocyte proliferation assay and organ cultures of human hair follicle as in vitro systems. The lotions with and without the penta-peptide were administered to 22 Japanese men with androgenetic alopecia (AGA) for 4 months in a double-blind and randomized clinical study. RESULTS: The penta-peptide significantly stimulated the proliferation of human hair keratinocytes at a concentration of 2.3 µm (P < 0.01), and 5.0 µm of this peptide had a marked effect on hair shaft elongation in the organ culture (P < 0.05). The change in the proportion of thick hair (≥60 µm) compared to baseline in patients that received the peptide was significantly higher than in the placebo (P = 0.006). The change in the proportion of vellus hair (<40 µm) was also significantly lower in the peptide group than in the placebo (P = 0.029). The penta-peptide also significantly improved the appearance of baldness (P = 0.020) when blinded reviewers graded photographs of the participants according to a standardized baldness scale. No adverse dermatological effects due to treatment were noted during this clinical study. CONCLUSIONS: This penta-peptide promotes proliferation of human hair keratinocytes and hair shaft elongation of human hair follicles, in vitro. This peptide increases thick hair ratio in vivo, and this compound is useful for the improvement of AGA.