Analysis of Slow Hyperpolarizing Potentials in Frog Taste Cells Induced by Glossopharyngeal Nerve Stimulation

Chemical Senses, 29,     

Employment of 16S rDNA gene sequencing techniques for improved identification of difficult-to-identify bacterial veterinary pathogens

To employ 16S rDNA PCR and automated sequencing techniques to identify a collection of bacterial veterinary pathogens from avian, equine, canine and ovine sources, that have proven difficult to identify, employing conventional cultural techniques. Universal or “broad-range” eubacterial PCR was performed on a collection of 46 difficult-to-identify bacterial isolates originating from clinical veterinary specimens. 16S rDNA PCR was performed using two sets of universal primers to successfully generate a composite amplicon of 1,068 bp, which was sequenced to obtain each isolate’s identity. Sequence analysis was able to identify all isolates examined with relative ease. Where the use of molecular identification methods is justified, such as in outbreak control or bioterrorism in animal health, employment of partial 16S rDNA PCR and sequencing employing universal or “broad-range” 16S rDNA, provides a valuable and reliable method of identification of such pathogens.     

Effect of surfactants on stability of Acinetobacter johnsonii S35 and Oligotropha carboxidovorans S23 coaggregates

The effect of anionic (sodium dodecyl sulphate or SDS) and cationic (cetyltrimethylammonium bromide or CTAB) surfactants on the stability of binary bacterial coaggregates comprising Acinetobacter johnsonii S35 and Oligotropha carboxidovorans S23 (both sewage sludge isolates) was studied and compared with that on the complex sewage sludge flocs. Both SDS and CTAB enhanced the bacterial coaggregation at their lower concentrations of 0.2 and 0.07 mg ml(-1), respectively. However, complete deflocculation of coaggregates was observed at 1 mg ml(-1) SDS and 0.3 mg l(-1) CTAB concentrations. Further, sewage sludge flocs did not deflocculate in the presence of CTAB, although a concentration-dependent deflocculation was observed in the presence of SDS. A. johnsonii S35 and O. carboxidovorans S23 cells were separately pretreated (prior to coaggregation) with the surfactants. In spite of the partial (complete) loss of viability during SDS (CTAB) pretreatment, washed cells still retained hydrophobic character and displayed significant coaggregation (aggregation index ranging from 84% to 97% in comparison to 96% in the case of non-treated cells), demonstrating reversibility of the surfactant induced deflocculation. Further, when exposed to lower concentration of surfactants (0.2 mg ml(-1) SDS), coaggregates were more resistant (76% viability) as compared to the individual partner (S35: 52%; S23: 39% viability). Since the coaggregates are stable and provide protection from surfactants at lower concentrations (those normally expected in the sewage treatment plants), their presence as well as a sustained role in the sewage sludge bioflocculation is evident.     

Pollination system and its significance on isolation and hybridization in JapaneseEpimedium (Berberidaceae)

Observations on native populations of JapaneseEpimedium have revealed that two types of effective pollinators can be recognized. One of the two types, which consists of small bees (mainlyAndrena spp. andLasioglossum spp.), is characterized by nondiscriminating behavior for collecting pollen and is commonly found inEpimedium. The other type, which comprises medium sizedTetralonia nipponensis and largerBombus diversus queens as main components, showed flower-dependent foraging fidelity associated with nectar-sucking behavior.T. nipponensis with a shorter proboscis pollinated flowers with a shorter spur ofE. trifoliatobinatum and of a part ofE. s sempervirens, while the queen ofB. diversus with a longer proboscis pollinated longer spurred flowers ofE. grandiflorum andE. sempervirens. In the populations of putative hybrid-derivatives which show gradational variations of spur length, bees of the pollencollecting type pollinated any flower non-discriminately while bees of the nectar-foraging type tended to visit the flowers with spur lengths corresponding to their proboscis length. These observations suggest that the pollen-collecting bees play an important role for gene flow among theEpimedium species, and the nectar-foraging bees reinforce the isolation between the species by their selective pollination. Reproductive isolation between species ofEpimedium is discussed in relation with some practical behavior, such as flying power, of the pollinators.     

Moulting of a deep-sea galatheid crab (Anomura, Galatheidae) at a depth of 3572 m

The moulting of the deep-sea galatheid crab, Mundopsissp. was observed using a seafloor observatory at a depth of 3572 m in Nankai Trough, western Japan. The duration of the ecdysis was 147 seconds. The crab rested on the substratum until ecdysis was complete. After ecdysis, it flicked and moved away from its exuviae. The newly moulted galatheid crab did not consume its cast exoskeleton.     

Instream distributions and feeding habits of two species of sleeper, <Emphasis Type="Italic">Eleotris acanthopoma</Emphasis> and <Emphasis Type="Italic">Eleotris fusca</Emphasis>, in the Teima River,Okinawa Island

The instream distributions and feeding habits of two species of sleeper, Eleotris acanthopoma and E. fusca, were studied in the Teima River on Okinawa Island, southern Japan. Both adult fishes inhabited the river, but their distribution patterns were found to be different. The distribution of E. acanthopoma was from the tidally influenced area to the lower part of the freshwater area, whereas E. fusca was distributed almost entirely in the freshwater area. They were found to coexist at the upper limit of the tidally influenced area and the lower part of the freshwater area. Their feeding habits were clearly different, although both species were carnivorous. Eleotris acanthopoma fed mainly on crabs in the tidally influenced area and on aquatic snails in the freshwater area, where they coexist with E. fusca. In contrast, E. fusca fed mainly on shrimps in the freshwater area. Their coexistence may result from the difference in their feeding habits.     

Reduction of vitamin K concentration by salivary Bifidobacterium strains and their possible nutritional competition with Porphyromonas gingivalis

AIMS: To assess the possibility that bifidobacteria compete with Porphyromonas gingivalis for their mutual growth factor vitamin K. This study also examined whether salivary Bifidobacterium species decrease vitamin K concentration in the growth medium. METHODS AND RESULTS: Sixty-five strains of Bifidobacterium were obtained from 20 of 24 periodontally healthy subjects. Bifidobacterium dentium was most frequently detected in the saliva of subjects, followed by Bifidobacterium adolescentis, Bifidobacterium longum, and Bifidobacterium urinalis. The growth of most Bifidobacterium isolates, except that of B. urinalis, was stimulated by vitamin K. Moreover, the isolates were capable of decreasing vitamin K after incubation, which suggests that bifidobacteria compete with P. gingivalis for vitamin K. In a co-culture, a representative strain -B. adolescentis S2-1 - inhibited the growth of P. gingivalis if it was inoculated in the medium before P. gingivalis. CONCLUSIONS: B. adolescentis S2-1 decreased vitamin K concentration and inhibited the growth of P. gingivalis by possibly competing for the growth factor. SIGNIFICANCE AND IMPACT OF THE STUDY: Salivary bifidobacteria may possess the potential to suppress the growth of P. gingivalis by reducing the growth factor(s) in the environment.     

Preface

Sleep and Biological Rhythms -     

Participation of caspase-3-like protease in oxidation-induced impairment of erythrocyte membrane properties

Erythrocytes are very susceptible to oxidative stress, having a high content of intracellular oxygen and hemoglobin. In the present study, exposure to oxidative stress resulted in a significant impairment of erythrocyte membrane functions, such as deformability and anion exchange. Band 3 protein, also known as anion exchanger-1, plays an important role in these two functions. We show that oxidative stress activated caspase-3 inside the erythrocytes, which resulted in band 3 protein cleavage. Interestingly, inhibition of the caspase-3 with its specific inhibitor not only suppressed the digestion of band 3 protein, but also blunted the functional damage to erythrocytes, such as deformability and anion exchange, without changing the level of peroxidation of membrane lipids. These results provide experimental evidence that activation of caspase-3 plays an important role in the oxidative stress-induced impairment of membrane functions of erythrocytes.     

Cryopreservation of rat MSCs by use of a programmed freezer with magnetic field

Mesenchymal stem cells (MSCs) can be used for the regeneration of various tissues and cryopreservation of MSCs is so important for regenerative medicine. The purpose of this study was to evaluate the influences of cryopreservation on MSCs by use of a programmed freezer with a magnetic field (CAS freezer). MSCs were isolated from bone marrow of rat femora. The cells were frozen by a CAS freezer with 10% dimethyl sulfoxide (Me2SO) and cryopreserved for 7 days at a temperature of −150 °C. Immediately after thawing, the number of survived cells was counted. The cell proliferation also examined after 48 h culture. Next, MSCs were frozen by two different freezers; CAS freezer and a conventional programmed freezer without magnetic field. Then, osteogenic and adipogenic differentiations of cryopreserved cells were examined. As a result, survival and proliferation rates of MSCs were significantly higher in CAS freezer than in the non-magnetic freezer. Alizarin positive reaction, large amount of calcium quantification, and greater alkaline phosphatase activity were shown in both the non-cryopreserved and CAS groups after osteogenic differentiation. Moreover, Oil Red O staining positive reaction and high amount of PPARγ and FABP4 mRNAs were shown in both the non-cryopreserved and CAS groups after adipogenic differentiation. From these findings, it is shown that a CAS freezer can maintain high survival and proliferation rates of MSCs and maintain both adipogenic and osteogenic differentiation abilities. It is thus concluded that CAS freezer is available for cryopreservation of MSCs, which can be applied to various tissue regeneration.