Dietary l-arginine supplementation enhances the immune status in early-weaned piglets

This study was conducted to test the hypothesis that dietary L-arginine supplementation enhances immunity in early weaned piglets. Seventy piglets weaned at 7 days of age were assigned to five groups (14 pigs/group), representing supplementation of 0.0, 0.2, 0.4, 0.6, and 0.8% L-arginine to a milk-based formula. On Day 7 after initiation of treatment, spleen weight in piglets supplemented with 0.2 and 0.8% arginine was heavier and thymus size was larger in piglets supplemented with 0.6% arginine, whereas serum concentration of immunoglobulin (Ig) M was higher but that of IL-8 was lower in piglets supplemented with 0.6 and 0.8% arginine, compared with the control group. Dietary supplementation with 0.8% arginine increased the numbers of white blood cells and granulocytes, and gene expression of interleukin (IL)-8 in spleen. On Day 14, compared with control piglets, granulocyte numbers were greater but lymphocyte numbers were lower in piglets supplemented with 0.2 and 0.4% arginine, whereas splenic expression of IL-8 and tumor necrosis factor-alpha genes was increased in piglets supplemented with 0.8% arginine. Additionally, IgG and IgM concentrations in serum and growth performance were greater in piglets supplemented with 0.4-0.8% arginine, compared with unsupplemented piglets. Collectively, dietary supplementation with 0.4-0.8% L-arginine for 2 weeks enhances both cellular and humoral immunity in piglets by modulating the production of leukocytes, cytokines and antibodies. These results indicate that increasing L-arginine provision is beneficial for optimal immune responses in young pigs and also have important implications for designing the next generation of improved formula for human infants.     

Crotonionosides A-G: megastigmane glycosides from leaves of Croton cascarilloides Räuschel

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Crotoncascarilloides, collected in Okinawa, Japan, seven megastigmane glycosides, named crotonionosides A-G, were isolated together with three known megastigmane glucosides, dendranthemosides A and B, and citroside A. This structures were elucidated by a combination of spectroscopic analyses, HPLC analyses, and application of the modified Mosher’s method.     

Unexpectedly complex gradation of coral population structure in the Nansei Islands,Japan

To establish effective locations and sizes of potential protected areas for reef ecosystems, detailed information about source and sink relationships between populations is critical, especially in archipelagic regions. Therefore, we assessed population structure and genetic diversity of Acropora tenuis, one of the dominant stony coral species in the Pacific, using 13 microsatellite markers to investigate 298 colonies from 15 locations across the Nansei Islands in southwestern Japan. Genetic diversity was not significant among sampling locations, even in possibly peripheral locations. In addition, our results showed that there are at least two populations of A. tenuis in the study area. The level of genetic differentiation between these populations was relatively low, but significant between many pairs of sampling locations. Directions of gene flow, which were estimated using a coalescence‐based approach, suggest that gene flow not only occurs from south to north, but also from north to south in various locations. Consequently, the Yaeyama Islands and the Amami Islands are potential northern and southern sources of corals. On the other hand, the Miyako Islands and west central Okinawa Island are potential sink populations. The Kerama Islands and the vicinity of Taketomi Island are potential contact points of genetic subdivision of coral populations in the Nansei Islands. We found that genetic population structure of A. tenuis in the Nansei Islands is more complex than previously thought. These cryptic populations are very important for preserving genetic diversity and should be maintained.     

Apparent Involvement of a β1 Type Integrin in Coral Fertilization

Integrins are involved in a wide variety of cell adhesion processes, and have roles in gamete binding and fusion in mammals. Integrins have been also discovered in the scleractinian coral Acropora millepora (Cnidaria: Anthozoa). As a first step toward understanding the molecular basis of fertilization in corals, we examined the effect of polyclonal antisera raised against recombinant coral integrins on gamete interactions in A. millepora. Antiserum raised against integrin βcn1 dramatically decreased the binding of Acropora sperm to eggs and significantly decreased fertilization rates relative to preimmune serum and seawater controls. However, the antiserum against AmIntegrin α1 did not affect significantly either sperm–egg binding or fertilization. One possible explanation for this is that AmIntegrin α1 may preferentially mediate interactions with RGD-containing ligands, whereas mammalian α6 integrin (which is most directly implicated in gamete interactions) preferentially interacts with laminin-related ligands. Our results suggest that β1 type integrins are involved in the fertilization process in Acropora and that some functions of these molecules may have been conserved between corals and mammals. A. Iguchi and L. M. Márquez contributed equally to this work.     

Microbial secondary metabolite induction of abnormal appressoria formation mediates control of rice blast disease caused by Magnaporthe oryzae

Okinawa, the only subtropical area in Japan with numerous island ecosystems, is expected to have diverse microbial resources. Recently, we reported the construction of a culture filtrate library with microbes originally isolated from soils in Okinawa, including the Yaeyama Archipelago, and validated its phylogenetic diversity. In the present study, we investigated the inhibitory effect of the cell extract (CE) from microbial isolate 3–45 against Magnaporthe oryzae in rice (Oryza sativa). Abnormal appressorium formation by M. oryzae was induced in the presence of the CE from isolate 3–45. Additionally, melanization of appressoria was inhibited in the presence of CE from isolate 3–45. Sequence analysis of the 16S rDNA region of isolate 3–45 indicated that it shared similarities with Streptomyces erythrochromogenes. When rice leaves were inoculated with M. oryzae in the presence of CE from isolate 3–45, blast lesion formation was inhibited compared to leaves treated with M. oryzae in the absence of CE from isolate 3–45. In addition, M. oryzae infective activity was significantly inhibited in rice leaf sheaths treated with CE from isolate 3–45. Furthermore, abnormal appressorium formation was observed in the presence of heat‐treated CE from isolate 3–45. These results suggest that CE from isolate 3–45 can protect rice from blast disease caused by M. oryzae. Further studies are required to identify the active compounds present in 3–45‐CE and to clarify its mechanism of inhibition in full detail. The present study on isolate 3–45 might contribute to the development of a new fungicide for controlling rice blast disease caused by M. oryzae.     

Application of Pseudomurein Endoisopeptidase to Fluorescence In Situ Hybridization of Methanogens within the Family Methanobacteriaceae

In situ detection of methanogens within the family Methanobacteriaceae is sometimes known to be unsuccessful due to the difficulty in permeability of oligonucleotide probes. Pseudomurein endoisopeptidase (Pei), a lytic enzyme that specifically acts on their cell walls, was applied prior to 16S rRNA-targeting fluorescence in situ hybridization (FISH). For this purpose, pure cultured methanogens within this family, Methanobacterium bryantii, Methanobrevibacter ruminantium, Methanosphaera stadtmanae, and Methanothermobacter thermautotrophicus together with a Methanothermobacter thermautotrophicus-containing syntrophic acetate-oxidizing coculture, endosymbiotic Methanobrevibacter methanogens within an anaerobic ciliate, and an upflow anaerobic sludge blanket (UASB) granule were examined. Even without the Pei treatment, Methanobacterium bryantii and Methanothermobacter thermautotrophicus cells are relatively well hybridized with oligonucleotide probes. However, almost none of the cells of Methanobrevibacter ruminantium, Methanosphaera stadtmanae, cocultured Methanothermobacter thermautotrophicus, and the endosymbiotic methanogens and the cells within UASB granule were hybridized. Pei treatment was able to increase the probe hybridization ratio in every specimen, particularly in the specimen that had shown little hybridization. Interestingly, the hybridizing signal intensity of Methanothermobacter thermautotrophicus cells in coculture with an acetate-oxidizing H₂-producing syntroph was significantly improved by Pei pretreatment, whereas the probe was well hybridized with the cells of pure culture of the same strain. We found that the difference is attributed to the differences in cell wall thicknesses between the two culture conditions. These results indicate that Pei treatment is effective for FISH analysis of methanogens that show impermeability to the probe.     

Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin.

Tritanopia is an autosomal dominant genetic disorder of human vision characterize by a selective deficiency of blue spectral sensitivity. The defect is manifested within the retina and could be caused by a deficiency in function or numbers (or both) of blue-sensitive cone photoreceptors. We have used PCR, denaturing gradient gel electrophoresis, and DNA sequencing of amplified exons to detect in four of nine unrelated tritanopic subjects two different point mutations in the gene encoding the blue-sensitive opsin, each leading to an amino acid substitution. Segregation analysis within pedigrees and hybridization of oligonucleotides specific for each allele to DNA samples from control subjects support the hypothesis that these mutations cause tritanopia. These results complete the genetic evidence for the trichromatic theory of human color vision.     

Unexpected diversity of cnidarian integrins: expression during coral gastrulation

Background  

Adhesion mediated through the integrin family of cell surface receptors is central to early development throughout the Metazoa, playing key roles in cell-extra cellular matrix adhesion and modulation of cadherin activity during the convergence and extension movements of gastrulation. It has been suggested that Caenorhabditis elegans, which has a single β and two α integrins, might reflect the ancestral integrin complement. Investigation of the integrin repertoire of anthozoan cnidarians such as the coral Acropora millepora is required to test this hypothesis and may provide insights into the original roles of these molecules.