A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis

Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.     

Annual dynamics of marine birnavirus (MABV) in cultured Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> and sea water

ABSTRACT:   Seasonal changes in the infection state of marine birnavirus (MABV) in Japanese flounder Paralichthys olivaceus and in rearing sea water are described. Sea water and 10–11 healthy fish were sampled monthly from April 2002 to February 2003. The MABV genome was detected throughout the year in > 80% of the fish examined at each sampling. The virus was isolated from the liver, kidney, and spleen, but not from the brain. The detection rate in each organ increased from April to October, and then decreased. Detection of virus antigen by the indirect fluorescent antibody technique also showed that the virus was present from spring to autumn (June–September) in the liver, kidney, and spleen, but not the brain. Sequence analysis of the MABV genome at the VP2–NS region revealed two specific mutations compared to the standard yellowtail strain (Y-6). It is suggested that the infection state of MABV in Japanese flounder changes to a latent or persistent infection after autumn. MABV was detected in sea water between September and February, suggesting that virus particles in the environment are relatively higher during cool seasons.     

DNA methylation profile: a composer-, conductor-, and player-orchestrated Mammalian genome consisting of genes and transposable genetic elements

Epigenetic systems play crucial roles in the differentiation of a mammalian fertilized egg into hundreds of cell types exhibiting distinct phenotypes, using a set of DNA molecules comprising about 3 billion nucleotides. Genome-wide analyses of epigenetic marks have revealed the remarkably well-established and well-maintained structure of the epigenome, consisting of DNA methylation and histone modifications that vary their state in a tissue type- and developmental stage-specific manner at numerous genomic loci. DNA methylation profiles comprising numerous tissue-dependent and differentially methylated regions (T-DMRs), found at such loci, are unique to every type of cell and tissue, and illuminate molecular networks that represent their phenotypes. T-DMRs are located in not only genic but also nongenic regions-including transposable genetic elements, such as short interspersed transposable element. Epigenetic studies indicate that the molecules that perform these modifications directly, such as DNA methyltransferases and eukaryotic histone methyltransferases, or indirectly, such as CpG-binding protein and noncoding RNAs-and combinations of these-contribute to the DNA methylation profile. It remains to be addressed how these molecules precisely find their target genomic loci.     

Naringenin and hesperetin induce growth arrest, apoptosis, and cytoplasmic fat deposit in human preadipocytes

Citrus flavonoids are reported to be promising bioactive compounds against hyperlipidemia and lipid biosynthesis. However, the mechanism of the lipid lowering effect by flavonoids remains unknown. The present study examines the effect of some flavanones on the adipocytic conversion of the human preadipocyte cell line, AML-I. Among four structure-related flavanones including naringenin, naringenin-7-rhamnoglucoside (naringin), hesperetin, and hesperetin-7-rhamnoglucoside (hesperidin), the aglycones such as naringenin and hesperetin exhibited the growth arrest of AML-I cells. When the cells were examined by Annexin V-FITC staining method, it was noticed that growth arrest was induced by apoptotic cell death. In the study of apoptosis-related protein in the naringenin-treated cells, anti-apoptotic proteins such as p-Akt, NF-kappaB, and Bcl-2 were decreased, and pro-apoptotic protein Bad was accumulated by Western blot analysis. Interestingly, exposure of AML-I cells to naringenin or hesperetin during short-term cultures increased cytoplasmic lipid droplets by Sudan Black B staining. Furthermore, expression of fatty acid synthase (FAS) and peroxisome proliferator activated receptor (PPAR)-gamma was enhanced in naringenin-treated cells. These data suggest that apoptosis by flavanones does not inhibit the adipocytic conversion of AML-I preadipocytes. The result also indicates that adipocyte may not be a direct target for the lipid-lowering activity of the flavanones.     

Paragonimus westermani metacercariae in two freshwater crab species in Kagoshima Prefecture,Japan, as a possible source of infection in wild boars and sika deer

Paragonimiasis is a particular foodborne parasitic disease that is endemic to southern Kyushu, including Kagoshima Prefecture, Japan. We previously detected Paragonimus westermani triploid larvae in meat samples obtained from wild boars and sika deer hunted in Akune City, Kagoshima Prefecture. These mammals act as paratenic hosts and their meat is a source of human paragonimiasis. Paratenic host mammals and humans become infected with the lung fluke, P. westermani, following consumption of second intermediate hosts, freshwater crab species, namely, Geothelphusa dehaani or Sawagani in Japanese, and Eriocheir japonica or Mokuzugani in Japanese. Therefore, this study aimed to investigate the current infection status of P. westermani in freshwater crabs in Akune City. We collected freshwater crabs from 15 locations and found that the prevalence of P. westermani metacercariae was 1.6% for Sawagani (15 of 941 examined) and 22.1% for Mokuzugani (21 of 95 examined). Based on the morphological characterization of metacercariae and molecular analyses of the internal transcribed spacer 2 region and mitochondrial 16S rRNA gene region using PCR-restriction fragment length polymorphism and sequencing, all metacercariae were identified as the triploid form of P. westermani. These results indicate that Sawagani and Mokuzugani serve as second intermediate hosts to maintain the life cycle of triploid P. westermani. Further, infection in crabs potentially leads to subsequent P. westermani infections in wild mammals, including wild boars and sika deer, both of which are considered important types of game meat in Japan.     

Stereoselective syntheses of all stereoisomers of lariciresinol and their plant growth inhibitory activities

All stereoisomers of lariciresinol were synthesized to examine the effect of stereochemistry on plant growth. Configuration of benzylic 7-positions was constructed through S(N)1 or S(N)2 intramolecular etherification. 8- and 8'-position configurations were established from the starting material except for all cis stereoisomers, the 8-position configurations of which were achieved by employing stereoselective hydroboration. (-)-Lariciresinol and its 7S,8S,8'R stereoisomer inhibited the root growth of Italian ryegrass to 51-55% relative to the negative control, whereas other stereoisomers had less effect. These results demonstrate that the stereochemistry of lignans is one of the important factors influencing their inhibitory activity.     

Accumulation and localization of cesium in edible mushroom (Pleurotus ostreatus) mycelia

The characteristics of Cs accumulation and localization in edible mushrooms were examined using the mycelia of Pleurotus ostreatus-Y1. Scanning electron microscope images revealed the existence of white spots, and energy dispersive X-ray microanalyzer analysis indicated the presence of larger amounts of Cs and P in these spots in mycelia cultured on medium containing 25 mM CsCl. The (137)Cs activities in the mycelia were approximately 4-6 times higher than those in water used for (137)Cs elution. Higher Cs concentrations in the sediment fraction including vacuolar pellets were obtained compared to the upper fractions. It was observed that yellowish spots caused by the fluorescence of 4',6-diamidino-2-phenylindole (DAPI)-stained polyphosphate were localized in the mycelia. The higher fluorescence intensity of the yellowish-grained spots was measured in comparison with other regions in the mycelium. These results suggested that Cs in the mycelia was trapped by polyphosphate in vacuoles or other organelles.     

Differential kinetic activities of glycerol kinase among African trypanosome species: phylogenetic and therapeutic implications

African trypanosome species are causative agents for sleeping sickness in humans and nagana disease in cattle. Trypanosoma brucei can generate ATP via a reverse reaction with glycerol kinase (GK) when alternative oxidase (AOX) is inhibited; thus, GK is considered to be a crucial target for chemotherapy combined with AOX. However, the energy metabolism systems of African trypanosome species other than T. brucei are poorly understood. Thus, GK genes were surveyed from genome databases and cloned by PCR from T. vivax and T. congolense. Then, recombinant GK proteins (rGK) of T. vivax, T. congolense and T. brucei were expressed and purified. Kinetic analysis of these rGK proteins revealed that the K(m) values of T. congolense rGK for ADP and G-3-P substrates were lower than those of T. vivax and T. brucei. The expression level of GK molecules was highest in T. congolense cells and lowest in T. vivax cells. Based on these results, effective combination dosages of ascofuranone, a specific inhibitor of AOX, and glycerol, an inhibitor of the GK reverse reaction, were determined by using in vitro-cultured trypanosome cells.     

A History of the International Conference of Animal Health Information Specialists (ICAHIS) and its Partnership in One Health

This article chronicles the International Conference of Animal Health Information Specialists’ (ICAHIS) beginning in 1992 to the present and describes other groups and conferences formed from the international animal health information conference idea. Throughout its history, ICAHIS has been a forum for colleagues worldwide to discuss, share, and promote animal health information access. This article is a brief history of ICAHIS's origins and the movement it fostered. The 7th ICAHIS, the first in the United States, will occur in Boston, May 3–8, 2013. Previous conferences were held on three continents: Europe, Africa, and Australia.