Plectosphaerella rot of lettuce, coriander, and chervil caused by Plectosphaerella pauciseptata

Rot diseases of hydroponically cultured leaf lettuce, coriander, and chervil were found in Chiba Prefecture, Japan. Stems and petioles of the three diseased plants became brown or black with a soft rot, and vascular parts of the stems became discolored. Seemingly similar fungi were isolated from the diseased plants. Pathogenicity of these fungal isolates to each plant was demonstrated by inoculation tests. The fungi were identified as Plectosphaerella pauciseptata based on morphological and cultural characters. This identification was supported by phylogenetic analysis with rDNA ITS1-5.8S-ITS2 regions. The diseases were named Plectosphaerella rot (Plectosphaerella huhai-byo in Japanese) of lettuce, coriander, and chervil.     

Plant regeneration by somatic embryogenesis from mature seeds of <Emphasis Type="Italic">Magnolia obovata</Emphasis>

We attempted to develop a method for the regeneration of plantlets from mature seeds of medically important Magnolia obovata via the induction of somatic embryogenesis in vitro. We initially cultured halves of mature seeds on either Murashige and Skoog (MS) medium or B₅ medium that contained 0, 1, 5 or 10 μM gibberellic acid (GA₃) for 1 month and then transferred the half-seeds to half-strength MS basal medium or B₅ basal medium for further culture in the absence of GA₃. Proembryogenic masses (PEMs) were observed 1 month after the transfer of the halved mature seeds to the medium without GA₃. The frequency of formation of PEMs was higher (28%) after initial culture in MS basal medium plus 1 μM GA₃ than in other tested media (0 or 4%). Somatic embryos that had been developed from PEMs were cultured on half-strength MS basal medium or B₅ basal medium for completion of maturation and then transferred to fresh aliquots of the same medium for initiation of germination. The frequency of germination, with the formation of normal primary leaves and roots, was above 80%. We transferred the somatic embryo-derived plantlets to soil for acclimatization and the plantlets continued to thrive.     

Root plasticity under fluctuating soil moisture stress exhibited by backcross inbred line of a rice variety,Nipponbare carrying introgressed segments from KDML105 and detection of the associated QTLs

In rainfed lowland rice ecosystem, rice plants are often exposed to alternating recurrences of waterlogging and drought due to erratic rainfall. Such soil moisture fluctuation (SMF) which is completely different from simple or progressive drought could be stressful for plant growth, thereby causing reduction in yield. Root plasticity is one of the key traits that play important roles for plant adaptation under such conditions. This study aimed to evaluate root plasticity expression and its functional roles in dry matter production and yield under SMF using Nipponbare, KDML 105 and three backcross inbred lines (BILs) and to identify QTL(s) associated with root traits in response to SMF at two growth stages using Nipponbare/KDML105 F₂ plants. A BIL, G3-3 showed higher shoot dry matter production and yield than Nipponbare due to its greater ability to maintain stomatal conductance concomitant with greater root system development caused by promoted production of nodal and lateral roots under SMF. QTLs were identified for total nodal root length, total lateral root length, total root length, number of nodal roots, and branching index under SMF at vegetative and reproductive stages. The QTLs detected at vegetative and reproductive stages were different. We discuss here that relationship between root system of G3-3 and the detected QTLs. Therefore, G3-3 and the identified QTLs could be useful genetic materials in breeding program for improving the adaptation of rice plants in target rainfed lowland areas.     

Development of a SYBR green real-time polymerase chain reaction assay for quantitative detection of Babesia gibsoni (Asian genotype) DNA.

A real-time fluorogenic polymerase chain reaction (PCR) assay based on SYBR green that allows for sensitive, reproducible, and accurate quantification of Babesia gibsoni (Asian genotype). DNA from peripheral blood of infected dogs was developed. Standard curves were created by plotting the input amount of a standard template, constructed with plasmid DNA containing 182 base pairs (bp) of the p18 gene, against threshold cycle numbers. The curves showed a wide dynamic range (1,000,000-fold input) and high correlation values (>0.99). The PCR amplification efficacy of the standard template was similar to that of intact genomic DNA obtained from peripheral blood with B. gibsoni infection. The detection limit of the assay was 9 parasites/microl of blood with B. gibsoni infection. The intra-assay and interassay coefficients of variation of the threshold cycles ranged from 0.70% to 1.89% and from 1.18% to 1.92%, respectively. This assay system was found to be reproducible and accurate for the quantification of parasite DNA in experimentally infected dogs and far more sensitive than traditional microscopic examination.     

Metagenomic profiles of the rumen microbiota during the transition period in low‐yield and high‐yield dairy cows

We investigated potential relationships between rumen microbiota and milk production in dairy cows during the transition period. Twelve dairy cows were divided into a low‐yield (LY) or high‐yield (HY) group based on their milk yield. Rumen samples were taken from dairy cows at 3 weeks before parturition, and at 4, 8, and 12 weeks after parturition. 16S rDNA‐based metagenomic analysis showed that diversities of rumen microbiota in both groups were similar and the number of operational taxonomic units (OTUs) was lower in the postpartum than prepartum period in both groups. The abundance of Bacteroidetes and ratio of Bacteroidetes:Firmicutes was higher in the HY than the LY group. OTUs assigned to Prevotella bryantii, Fibrobacter succinogenes, Ruminococcus albus, Butyrivibrio fibrisolvens, and Succinivibrio sp. were abundant in the HY group. These OTUs were significantly related to the propionate molar proportion of rumen fluids in the HY group. OTUs assigned to Lachnospiraceae, Bifidobacterium sp. and Saccharofermentans were dominant in the LY group. Predictive functional profiling revealed that abundance of gene families involved in amino acid and vitamin metabolism was higher in the HY than the LY group. These results suggest that the community structure and fermentation products of rumen microbiota could be associated with milk production of dairy cows.     

Structure-activity study of herbicidal N-chloroacetyl-N-phenylglycine esters

N-Chloroacetyl-N-phenylglycine esters were shown to exert various degrees of growth inhibiting activity against young shoots of annual grasses. The activity against the rice plant and barnyard-grass was determined for 58 derivatives where either the aromatic substituent or ester moiety was modified. The structure-activity relationships were analyzed using physicochemical parameters of the molecule such as log P, σ, and E_s, and regression analysis. By comparing the correlations derived for the rice plant and barnyard-grass, the selectivity in herbicidal activity is discussed.     

Ontogenetic changes in water-use efficiency (δC) and leaf traits differ among tree species growing in a semiarid region of the Loess Plateau,China

On the Loess Plateau, China, several planted tree species such as Populus hopeinsis and Robinia pseudoacacia suffer occasional diebacks in the top shoots, reducing growth rates after maturation. However, this does not usually occur in other species, e.g., Ulmus pumila and Zizyphus jujuba. We compared stable carbon isotope ratios (δ¹³C) as indicators of leaf water-use efficiency (WUE), leaf mass per unit area (LMA), and leaf area- and mass-based nitrogen content (N_area and N_mass) by tree height (1, 5, and 10 m) in P. hopeinsis, R. pseudoacacia, U. pumila, and Z. jujuba. In P. hopeinsis and R. pseudoacacia, leaf δ¹³C and N_area were significantly lower in 10-m trees than in 1-m saplings, indicating that leaf WUE and photosynthetic rates of both species decreased with tree height. In contrast, δ¹³C in Z. jujuba varied little with tree height. The δ¹³C of 10-m-tall U. pumila trees was significantly higher than that of 1-m plants, demonstrating an increase in WUE with tree height. Decreasing WUE, leaf N_area, and N_mass with height increases in P. hopeinsis and R. pseudoacacia may be related to water and nutrient limitations for these species in semiarid regions. In contrast, stable or increasing δ¹³C with tree height in U. pumila and Z. jujuba may account (to some extent) for successful production of these species under identical environmental conditions. Diameter growth rate also decreased with maturity in P. hopeinsis and R. pseudoacacia, but increased or was stable for U. pumila and Z. jujuba. The differences in leaf WUE and LMA among species with tree maturity may be related to species’ growth patterns and susceptibility to drought stress, and are likely to be important new criteria for plantation species selection on the Loess Plateau.     

Analysis of plasmids encoding the histidine decarboxylase gene in Tetragenococcus muriaticus isolated from Japanese fermented seafoods

In order to analyze the genes related to histamine production in halophilic lactic acid bacteria, 16 strains of histamine-producing bacteria were isolated from three fermented seafoods produced in the Hokuriku region of Japan. Phenotypic and 16S rRNA gene sequence analyses identified all of the strains as those of Tetragenococcus muriaticus. Pyruvoyl-dependent histidine decarboxylase gene (hdcA) was determined from all strains using the PCR method with an hdcA-specific detection primer set. Genetic analyses (Southern blot and restriction fragment length polymorphism analysis) of hdcA and genes related to histamine production (the hdc cluster) confirmed that all of the strains harbored 21–23 kbp plasmids encoding a single copy of hdcA. The four representative strains were selected based on isolation source and genetic analysis, and subsequently full sequences of plasmids harbored in these strains were determined. hdc cluster sequences from the plasmids showed very high similarity (>99 %) to known hdc clusters of T. halophilus, Lactobacillus hilgardii 0006, and other lactic acid bacteria. The structures of the plasmids, the replication region, the hdc cluster, and the plasmid maintenance system were conserved between the plasmids present in new isolates and the T. halophilus strains. These results indicate that plasmids encoding hdcA are widely distributed among T. halophilus and T. muriaticus and function in both species.     

Structural analysis of monocyte activation constituents in cultured mycelia of Cordyceps sinensis

It has been reported that mycelia of the Cordyceps sinensis (CS) can function as an immunostimulant. However, the active constituents of the mycelia are not well known. In this study, we investigated which components of the mycelia of CS induce monocyte activation and then structurally analyzed the active components.     

Beneficial effect of hyperbaric oxygen therapy on the follicular survival in the mouse ovary after transplantation

A large proportion of follicles are lost during the initial ischemia that occurs after transplantation of ovarian tissues. Thus, the effect of hyperbaric oxygen therapy (HBO) on the follicular loss of ovarian tissues after transplantation was examined in mice. Ovarian slices from ICR mice were transplanted under the kidney capsule in ovariectomized ICR. Hyperbaric oxygen with 100% oxygen was initiated for 30 min at 2.5 atmospheres absolute immediately after transplantation, and this treatment was repeated at 48-h intervals for 2 weeks. The number of follicles was dramatically reduced at 2 weeks post transplantation. However, HBO was significantly effective in enhancing the survival of transplanted ovarian follicles. The survival rates of primordial and primary follicles in ovarian tissues of mice with HBO were significantly higher than those without HBO. These results indicate HBO can be effectively used for the enhancement of survival of transplanted ovarian tissues.