Optimal Light Regime for the Cultivation of Transgenic Laminaria japonica Gametophytes in a Bubble-column Bioreactor

Fluctuating light intensity had a more significant impact on growth of gametophytes of transgenic Laminaria japonica in a 2500 ml bubble-column bioreactor than constant light intensity. A fluctuating light intensity between 10 and 110 μE m⁻² s⁻¹, with a photoperiod of 14 h:10 h light:dark, was the best regime for growth giving 1430 mg biomass l⁻¹.     

Variation in karyotypes of Dugesia japonica japonica (Turbellaria) from Ôsaka Prefecture,Central Japan

An analysis of the karyotypes of Dugesia japonica japonica Ichikawa et Kawakatsu, 1964, from 30 localities of seven river systems in Ôsaka Prefecture, Central Japan, revealed a total of 26 karyotypes of which 12 are new-found varieties. More than two karyotypes were found in many localities. The mixoaneuploidic triploid karyotype showed the widest distribution (21 localities), orthoploidic diploid karyotype and orthoploidic mixoploid of diploid and triploid karyotype were next (13 localities, respectively), and other karyotypes (triploidic aneuploid, orthoploidic triploid and mixoploid of triploid & tetraploid) were also found. Some correlation of karyotype with elevation was also detected.     

Genetic dissection of top three leaf traits in rice using progenies from a japonica × indica cross

The size of the top three leaves of rice plants is strongly associated with yield; thus, it is important to consider quantitative traits representing leaf size(e.g.,length and width) when breeding novel rice varieties.It is challenging to measure such traits on a large scale in the field, and little is known about the genetic factors that determine the size of the top three leaves. In the present study, a population of recombinant inbred lines(RILs) and reciprocal single chromosomal segment substitution lines(SSSLs) derived from the progeny of a japonica Asominori ? indica IR24 cross were grown under four diverse environmental conditions. Six morphological traits associated with leaf size were measured,namely length and width of the flag, second and third leaves. In the RIL population, 49 QTLs were identified that clustered in 30 genomic region. Twenty-three of these QTLs were confirmed in the SSSL population. A comparison with previously reported genes/QTLs revealed eight novel genomic regions that contained uncharacterized ORFs associated with leaf size. The QTLs identified in this study can be used for markerassisted breeding and for fine mapping of novel genetic elements controlling leaf size in rice.     

Molecular phylogeny reveals the presence of cryptic speciation within Erysiphe japonica (≡ Typhulochaeta japonica), a powdery mildew on Quercus spp.

Molecular phylogenetic analyses based on 28S, ITS and IGS rDNA sequences indicate that Erysiphe japonica (≡ Typhulochaeta japonica) consists of two different genetic groups, one group on Quercus aliena, Q. robur and Q. serrata, and another group on Q. crispula var. crispula and Q. crispula var. horikawae. As morphological difference between the two groups are not yet marked distinctly, we suppose that the process of speciation has not yet been finished and propose a new variety, E. japonica var. crispulae, for the latter group based on the difference in host range and the distinct genetic segregation. Quercus robur (pedunculate oak) is a new host of E. japonica.     

Genetic Mapping of Laminaria japonica and L. Iongissima Using Amplified Fragment Length Polymorphism Markers in a ＂Two-Way Pseudo- Testcross＂ Strategy

With a ＂two-way pseudo-testcross＂ mapping strategy, we applied the amplified fragment length polymorphism （AFLP） markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F1 cross family （Laminaria iongissima Aresch. × L. Japonica Miyabe） with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1：1 ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3：1 Mendelian segregation ratio. Among the loci with 1：1 segregating ratios, 79 loci were ordered in 14 linkage groups （648.6 cM） of the paternal map, and 72 loci were ordered in 14 linkage groups （601.9 cM） of the maternal map. The average density of loci was approximately 1 per 8 cM. To Investigate the homologies between two parental maps, we used 58 loci segregated 3：1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.     

Immunolocalization of estrogen receptor α in Neomysis japonica oocytes and follicle cells during ovarian development

Estrogen induces oocytes development and vitellogenesis in crustacean by interacting with estrogen receptor (ER) subtypes. In the present study, we detect for the first time the ERα in oocytes and follicle cells and hepatopancreas cells of mysis by immunohistochemistry using a specific ERα antibody. ERα was mainly localized in the nuclei of oocytes and follicle cells, while mainly detected in nuclei of oogonia (OG), previtellogenic oocyte (PR) and endogenous vitellogenic oocyte (EN) at previtellogenic and early vitellogenic stage (I-early III). Follicle cells in all stages of ovary (all vitellogenic stages) showed strong ERα positive reaction, and they were able to gradually move to oocytes during the development of oocytes. In addition, ERα was also localized in the nuclei and cytoplasm of four hepatopancreas cells (including E-, R-, F- and B-cell) in all ovary stages. These findings suggest, for the first time to our knowledge, that there could be a close link between oogenesis, follicle cells, hepatopancreas cells and endocrine regulation, and estrogens might be involved in the regulation of oocytes at early ovarian stage in mysis.     

Is there a pilot in a pseudopod?

The concept of pilot pseudopodia is reconsidered 30 years after its inauguration (Gerisch, G., Hülser, D., Malchow, D., Wick, U., 1975. Cell communication by periodic cyclic-AMP pulses. Phil. Trans. R. Soc. Lond. B 272, 181-192). The original hypothesis stated that protruding pseudopodia serve as dynamic sensory organelles that aid a cell in perceiving variations of chemoattractant concentration and, consequently, in navigation during chemotaxis. This influential idea is reevaluated in the light of recent findings about the mechanisms governing chemotactic cell motility, morphology and dynamics of pseudopodia, and about molecular constituents and regulators of pseudopod extension and retraction. It is proposed that stimulation by a chemoattractant modulates speed of pseudopod protrusion and thereby increases cell elongation. Elongation further enhances chemotactic sensitivity of the cell to shallow chemoattractant gradients, reinforces cell polarization, and finally leads to suppression of lateral pseudopodia and continuation of cell migration in the gradient direction.     

What's in a name?

The names of organisms have major impacts on the geopolitical world. The current state of flux in the taxonomy of the genera Cryptosporidium and Giardia illustrates the effects that names can have on environmental and governmental policy. Taxonomy remains a vital science that is very much alive in the application of modern methods for describing morphologically cryptic species.     

What's in a centromere?

The complete sequence of rice centromere 8 reveals a small amount of centromere-specific satellite sequence in blocks interrupted by retrotransposons and other repetitive DNA, in an arrangement that is strikingly similar in overall size and content to other centromeres of multicellular eukaryotes.     

Production Ecology of the Non-indigenous Seagrass, Dwarf Eelgrass (Zostera japonica Ascher. & Graeb.), in a Pacific Northwest Estuary, USA

The non-indigenous seagrass Zostera japonica Ascher. & Graeb. (dwarf eelgrass) was first identified in central Oregon (USA) estuaries about 30 years ago. The autecology of this species is poorly described at the southern end of its non-native range although several process oriented studies have been conducted. I examined the production ecology of Z. japonica in the Yaquina Bay estuary. Strong seasonal patterns in light and temperature appeared to control the seasonal variations in biomass and growth. Above- and below-ground biomass ranged between 40–100 and 70–170 gdw m⁻² respectively and seasonal changes in the root:shoot ratio were controlled by above-ground biomass dynamics. Shoot density ranged between 4000 and 11 000 shts m⁻². Areal leaf growth ranged between 0.1 and 1.7 gdw m⁻² d⁻¹ and annual production was about 314 ± 60 gdw m⁻² y⁻¹ (mean ± SD). Nutrients were not limiting in this system as a result of coastal upwelling and watershed inputs. The Z. japonica population studied in Oregon exhibited different patterns of persistence, phenology and flowering intensity relative to other populations along its native and non-native range. These differences suggest that management policies developed for one site may not be appropriate for other sites. The data presented here greatly expands our knowledge base on Z. japonica and provides insight to the processes controlling the dynamics and spread of this non-indigenous seagrass. An erratum to this article is available at .     

苔藓Bazzania japonica挥发油的化学成分研究

采用水蒸气蒸馏法提取苔藓Bazzania japonica的挥发油,用毛细管色谱法对挥发油进行了分析,采用归一化法确定各组分的相对含量,并用GC-MS联用技术对分离的化学成分进行鉴定。经计算机检索并结合文献调研,共鉴定出38个化合物,占挥发油总量的83％,其中含2个单萜、31个倍半萜（其中11个为含氧倍半萜）和4个二萜（其中1个为含氧二萜）,主要成分为4-epi-11-nor—aristola-1（10）,11-diene（10．5％）,4-epi-11-nor-aristo-la-1,9,11-triene（6．5％）,β-caryophyllene（8．0％）,β—barbatene（7．2％）,globulol（8．8％）,aristol-1（10）-en-12-ol（9．1％）,和tridensenone（8．7％）.