Effects of clutch size and egg-laying order on the breeding success in the Little Tern Sterna albifrons on the Nakdong Estuary, Republic of Korea

Survivorship of Little Tern Sterna albifrons eggs and chicks was followed on an islet in the Nakdong Estuary, Republic of Korea, in 1995 and 1996. Mean egg size and incubation period were significantly different between the 2 years. The maximum clutch size was three eggs, and the second egg in the clutch often hatched earlier than the first, while most of the third eggs hatched last. In 1996, when the fate of 249 eggs from 106 nests was followed for 40 days, hatching success, fledging success and breeding success were 77%, 40% and 31%, respectively. High mortality occurred in the early chick stage, mostly because of rain and predation by Weasels Mustela sibirica. The breeding success per egg was 14% in one-egg clutches, 28% in two-egg clutches and 34% in three-egg clutches. This difference was mainly attributed to the lower hatching success in the smaller clutches. In three-egg clutches, the third egg showed significantly lower breeding success than siblings. The main foods of the Little Tern were Tridentiger obscurus, Engraulis japonicus, Hyporhamphus intermedius, Acanthogobius flavimanus (all fish), Palaemon sp. and Crangon affinis (shrimps). The feeding frequency was, apparently, not affected by time of day and age of chicks but was probably influenced by weather conditions. Newly hatched chicks failed to eat 25% of the prey brought to them, although this decreased with the age of the chicks.     

Labile ecotypes accompany rapid cladogenesis in an adaptive radiation of Mandarina (Bradybaenidae) land snails

The endemic land snail genus Mandarina of the oceanic Bonin Islands shows exceptionally diverse morphological and ecological traits. Previous studies have already provided evidence that speciation on different islands of the three main archipelagos was such that similar ecotypes evolved independently in different lineages and islands. Here we present data to show that the same species can have different ecotypes. As most of the characters involved are inherited, then variation between ecotypes must represent genetic differences between populations. We then show that the radiation on the Bonin Islands is derived from a single colonization event, and use a mitochondrial phylogeny to provide evidence for a burst of cladogenesis soon after colonization. As divergent selection has previously been implicated in causing differences between Mandarina species, and theory predicts that most of the speciation should have taken place early in their history, then the study adds to the evidence for an adaptive radiation by ecological speciation in Mandarina . However, while the diversity of ecotypes present at each site is dependent on the regime of natural selection and competition, geography still must have an important role.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 269–282.     

Expression of Tyrosinase Gene in Transgenic Albino Mice: The Heritable Patterned Coat Colors

To elucidate the regulatory mechanism for tyrosinase gene expression in vivo, we microinjected a mouse tyrosinase minigene, mg-Qrs-J, into the fertilized eggs of BALB/c albino mice. As a result, we obtained six pigmented founder mice that exhibited non-standard coat color variations as well as the wild-type phenotype. These founder mice were subsequently crossed with BALB/c albino mice to establish the transgenic lines. As a consequence, two primary lines and five sublines have been obtained from four of the six founder mice. We found that not only uniformly pigmented phenotypes but also patterned phenotypes were inherited by their descendants. The possible underlying mechanism of the patterned phenotypes is discussed.     

Activities and distribution of methanogenic and methane‐oxidizing microbes in marine sediments from the Cascadia Margin

We investigated methane production and oxidation and the depth distribution and phylogenetic affiliation of a functional gene for methanogenesis, methyl coenzyme M reductase subunit A (mcrA), at two sites of the Integrated Ocean Drilling Program Expedition 311. These sites, U1327 and U1329, are respectively inside and outside the area of gas hydrate distribution on the Cascadia Margin. Radiotracer experiments using ¹⁴C‐labelled substrates indicated high potential methane production rates in hydrate‐bearing sediments [128–223 m below seafloor (mbsf)] at U1327 and in sediments between 70 and 140 mbsf at U1329. Tracer‐free experiments indicated high cumulative methane production in sediments within and below the gas hydrate layer at U1327 and in sediments below 70 mbsf at U1329. Stable tracer experiments using ¹³C‐labelled methane showed high potential methane oxidation rates in near‐surface sediments and in sediments deeper than 100 mbsf at both sites. Results of polymerase chain reaction amplification of mcrA in DNA were mostly consistent with methane production: relatively strong mcrA amplification was detected in the gas hydrate‐bearing sediments at U1327, whereas at U1329, it was mainly detected in sediments from around the bottom‐simulating reflector (126 mbsf). Phylogenetic analysis of mcrA separated it into four phylotype clusters: two clusters of methanogens, Methanosarcinales and Methanobacteriales, and two clusters of anaerobic methanotrophic archaea, ANME‐I and ANME‐II groups, supporting the activity measurement results. These results reveal that in situ methanogenesis in deep sediments probably contributes to gas hydrate formation and are inconsistent with the geochemical model that microbial methane currently being generated in shallow sediments migrates downward and contributes to the hydrate formation. At Site U1327, gas hydrates occurred in turbidite sediments, which were absent at Site U1329, suggesting that a geological setting suitable for a gas hydrate reservoir is more important for the accumulation of gas hydrate than microbiological properties.     

Estimating the beginning day of Japanese cedar pollen release under global climate change

This study examined the effects of snowfall on the beginning day of Cryptomeria japonica pollen release and predicted it under global climate change. We used a statistical method in order to investigate when the pollen release would start and how much sooner it would be, by using data on predicted meteorological conditions under global warming in Yamagata City, Japan. Estimation accuracy was improved by multiple regression by using the mean air temperature from January to February and snowfall depth in February. Adding snowfall depth yielded more accurate estimates of the beginning day of pollen release than using air temperature alone. It is possible that the effects of heat insulation and cooling by snow delay the flowering day. Under the predicted global climate change, we expect the beginning day of pollen release to become earlier in Yamagata City. The date would be 8 February in approximately 100 years, compared with 20 February at the earliest now. Eighty years from now the date could be earlier than any date recorded so far.     

Molecular phylogenetic analysis of Podostemaceae: implications for taxonomy of major groups

The river‐weed family Podostemaceae (c. 300 species in c. 54 genera) shows a number of morphological innovations to be adapted to its unusual aquatic habitat, and its unique or rare bauplan features have been reflected in the traditional (i.e. non‐molecular) classification recognizing numerous monotypic or oligospecific genera. The infrasubfamilial relationships of many genera remained unclear. The present study used molecular phylogenetic analysis of matK sequences for 657 samples (c. 132 species/c. 43 genera). The family was traditionally divided into three subfamilies (Podostemoideae, Tristichoideae and Weddellinoideae). American Podostemoideae were shown to be polyphyletic and divided into four clades, i.e. Ceratolacis, Diamantina, Podostemum and all other genera. Among the podostemoid clades, Diamantina was the first branching clade and a clade comprising Mourera and the Apinagia subclade was then sister to the remainder of the New World and Old World Podostemoideae with low statistic supports. The Old World Podostemoideae comprised four monophyletic clades, i.e. two African clades, one Madagascan clade and one Asian clade, although the relationships among these clades and American Ceratolacis and Podostemum were poorly resolved. African Podostemoideae were polyphyletic, with Saxicolella pro parte being weakly supported as sister to the remaining Old World Podostemoideae plus Ceratolacis and Podostemum. In contrast to the American and African clades, monophyly of four Asian subclades was well supported. Plants of Tristicha (Tristichoideae) and of Weddellina (Weddellinoideae), which are currently treated as monospecific, had great matK differentiation equivalent to at least interspecific variation. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 461–492.     

Food web structure of the fungivorous insect community on bracket fungi in a Bornean tropical rain forest

1. If fungivorous insect diversity is maintained by host specialisation on particular fungi, it should be higher in the tropics than in temperate or boreal regions owing to high macrofungus species diversity. 2. To reveal the community and food web structure of fungivorous insects on bracket fungi, fungivorous insects were collected from 427 fruiting bodies belonging to 22 genera throughout the development and deterioration process in a 3‐ha plot of lowland dipterocarp tropical rain forest on Borneo Island. 3. Eight hundred and twenty‐nine individuals of 82 coleopteran species in 13 families from 111 fruiting bodies of 15 fungal genera were collected. Tenebrionidae and Staphylinidae were most common. Fifty‐three and 19 insect species were observed on Ganoderma and Phellinus, respectively. The numbers of insect species and individuals on a particular fungal genus were positively correlated with the abundance of that fungal genus. 4. Quantitative food web analysis revealed a high degree of specialisation at the whole‐community level. At least 65% of insect individuals were observed on Ganoderma at every stage of development and deterioration. Diverse insects coexist on one dominant fungal genus, Ganoderma, in contrast to our hypothesis. 5. The high abundance of Ganoderma fruiting bodies, which lack obvious defences against insect feeding, probably influences the bracket fungus–insect food web in this tropical rainforest.     

Detection of Mouse Tyrosinase With a Monoclonal Antibody MAT-1 Against Human Tyrosinase

In this study we explored the possible application of MAT-1, which has been established as a monoclonal antibody against human tyrosinase, for detection of mouse tyrosinase. The MAT-1 reacted with B16 mouse melanoma cells, but not with tyrosinase-negative NIH-3T3 mouse fibroblasts. In western blot analysis of the large granule fraction (LGF) of B16 cells, MAT-1 detected a single protein of 80 kDa, whose size was close to that of human tyrosinase detected with MAT-1 in extracts of human melanocytes. Furthermore, the 80 kDa band that was detected with MAT-1 in the LGF of B16 cells was also detected by DOPA reaction. In order to confirm that the protein detected with MAT-1 is tyrosinase, a transient expression assay was carried out. When mouse tyrosinase or mouse tyrosinase-related protein 1, which shares high homology with human tyrosinase, was transiently expressed in tyrosinase-negative K1735 mouse melanoma cells by cDNA transfection, MAT-1 reacted only with the cells expressing mouse tyrosinase. These results indicate that MAT-1 specifically reacts with mouse tyrosinase.     

Quantitative Analysis of Striped Coat-Color Patterns in Large White→Duroc Chimeric Pigs With Special Reference to the Genetic Control Mechanisms of the Dominant Black-Eyed White Phenotype

Coat colors of four chimeric pigs produced by the microinjection of dissociated blastomeres of (Landrace × Large White) blastocysts to the blastocyst cavity of (Duroc × Duroc) blastocysts (Kashiwazaki et al., 1992) exhibited characteristic horizontal stripe-patterns. We carried out quantitative analysis of those patterns in order to derive information concerning the genetic regulatory mechanisms of the dominant black-eyed white phenotypes in the pig. In the four chimeras, the theoretical mean widths of the single-clone stripe calculated from the estimated widths of minimal recognizable stripe (MRS) (Tachi, 1988) were 2.1 ± 0.1, 2.23 ± 0.15,1.89 ± 0.06, and 1.93 ± 0.28 cm respectively. The estimated number of single-clone stripes in the thoracico-lumbar region of those animals were 42.3, 40.7, 46.3, 44.2, and about twice the mean number of vertebrae in the same region (Duroc, 20 or 21; Large White, 21 or 22). Furthermore, the mean length of thoracico-lumbar vertebrate in two of the chimeric pigs, as measured on X-ray radiographs, was approximately twice the mean single-clone stripe width. It was concluded that the stripe-patterns of the chimeric pigs probably represented the dermatome patterns of epidermis; and in the pig, a single somite was likely to be derived from the clones of two primordial cells, as originally proposed by Gearhart & Mintz (1972) in the mouse. It was suggested, furthermore, that in the Large White→Duroc chimeric pigs, melanocytes that migrated into the region of skin formed by a Large White dermatome could not survive, thus creating a clearly demarcated white stripe. Possible involvement of KL or c-kit in the dominant black-eyed white phenotype of the pig is discussed.