First report of celery stunt anthracnose caused by <Emphasis Type="Italic">Colletotrichum simmondsii</Emphasis> in Japan

A new disease was found in Japan, on celery (Apium graveolens var. dulce) having severe chlorotic leaf spot, stunt, and dwarf with leaf curl. A spore suspension from the fungus isolated from affected plants induced identical symptoms 14 days after plants were sprayed. Identification and molecular characterization showed that the causal agent is Colletotrichum simmondsii. This report is the first of stunt anthracnose on celery caused by C. simmondsii. We propose the name “stunt anthracnose” for the new disease. Colletotrichum acutatum sensu lato, as reference pathogen of celery anthracnose, should be changed to C. fioriniae based on morphological and molecular characteristics.     

Fine structure and differentiation of the alimentary canal in captive-bred Japanese eel Anguilla japonica preleptocephali

ABSTRACT:   The fine structure of the alimentary canal in preleptocephali produced by artificially matured Japanese eel was examined. At 1 day posthatch (dph), the alimentary canal was found only above the dorsal side of the yolk mass, and the epithelium was composed of a single layer of epithelial cells. By 5 dph, the alimentary canal was divided into three segments based on the structure of the epithelial cells: foregut, midgut and hindgut, corresponding to the future esophagus, intestine and rectum, respectively. After 7 dph, the epithelium in the foregut was surrounded by a circular muscle layer, suggesting a role in the transportation of food materials. The epithelial cells of the midgut exhibited well-developed membranous structures, which are deduced to be invaginations of the cytoplasmic membrane. Pinocytotic invaginations and vacuoles were observed in the epithelial cells of the hindgut; this observation suggests that this region is involved in the uptake of food. Significant changes in morphological features of the epithelial cells in each segment were observed until 7 dph; however, these were not evident between 7 dph and 13 dph. Consequently, the differentiation of the alimentary canal was completed by 7 dph, and preleptocephalus had developed the ability to absorb food by 7 dph.     

家蚕脂肪体合成蛋白质变化的研究

应用双向电泳、同位素标记、放射自显影及计算机蛋白质电泳图谱分析技术研究了家蚕 5龄期和变态期脂肪体合成蛋白质的变化。结果表明 ,在 5龄中期脂肪体合成蛋白质的种类、分泌蛋白质的量、合成蛋白质的速度都达到最大值 ,合成脂肪体组织蛋白质在 5龄中期也快速增加 ,显示在 5龄中期脂肪体的蛋白质合成水平达到最大值 ,而熟蚕期后脂肪体合成蛋白质种类、分泌量及合成速度都下降 ,表明脂肪体蛋白质合成水平下降 ,在蛋白质合成水平上证明了家蚕脂肪体从幼虫期的合成、代谢等主要功能向变态期的贮藏功能转变。     

Macrolides and lincomycin susceptibility of Mycoplasma hyorhinis and variable mutation of domain II and V in 23S ribosomal RNA

A total of 151 strains of Mycoplasma hyorhinis isolated from porcine lung lesions (weaned pigs, n=71, and finishers, n=80) were investigated for their in vitro susceptibility to 10 antimicrobial agents. Thirty-one strains (28 from weaned pigs and 3 from finishers) showed resistance to 16-membered macrolide antibiotics and lincomycin. The prevalence of the 16-membered macrolide-resistant M. hyorhinis strain in weaned pigs from Japanese herds has approximately quadrupled in the past 10 years. Several of the 31 strains were examined for mutations in the 23S ribosomal RNA (rRNA). All field strains tested showed a transition of A to G at position 2059 of 23S rRNA-rendered Escherichia coli. On the other hand, individual tylosin- and lincomycin-resistant mutants of M. hyorhinis were selected in vitro from the susceptible type strain BTS7 by 3 to 9 serial passages in subinhibitory concentrations of each antibiotic. The 23S rRNA sequences of both tylosin and lincomycin-resistant mutants were compared with that of the radical BTS7 strain. The BTS7 mutant strain selected by tylosin showed the same transition as the field-isolated strains of A2059G. However, the transition selected in lincomycin showed mutations in domains II and V of 23S rRNA, G2597U, C2611U in domain V, and the addition of an adenine at the pentameric adenine loop in domain II. The strain selected by lincomycin showed an additional point mutation of A2062G selected by tylosin.     

Isolation of a human erythrocyte-adapted substrain of Babesia rodhaini and analysis of the merozoite surface protein gene sequences

Babesia rodhaini is a rodent hemoparasite closely related to B. microti, the major causative agent of human babesiosis. We tested the infectivity of B. rodhaini for human erythrocytes by using the SCID mouse model in which the circulating erythrocytes were replaced with those of humans. Initially, parasites grew very poorly in the mouse model, but a variant capable of propagating in human erythrocytes emerged after an adaptation period of three weeks. In an attempt to identify parasite proteins involved in the alteration of host cell preference, an expression cDNA library of B. rodhaini was constructed and screened with immune mouse sera. Although we were able to obtain three merozoite surface protein (MSP) genes, sequences of these genes from both the parental strain and human erythrocyte-adapted substrain were identical. Our results suggest that B. rodhaini has potential ability to infect human erythrocytes, but development of this ability may not be brought about by an amino acid change in MSPs.     

Migration of primordial germ cells isolated from embryonic blood into the gonads after transfer to stage X blastoderms and detection of germline chimaerism by PCR

1. The present study was carried out to determine whether primordial germ cells isolated from embryonic blood can enter the bloodstream and successfully migrate to the germinal ridges of recipient embryos after transfer to stage X blastoderms, and also whether they can differentiate into blood cells, as is suggested in mice. 2. Primordial germ cells were transfected in vitro by lipofection and then transferred to stage X blastoderms. The introduced GFP gene was efficiently expressed in the gonads of 6-d incubated embryos. 3. Freshly collected primordial germ cells were transferred to stage X blastoderms. The fate of the transferred primordial germ cells was traced by detecting the single nucleotide polymorphism in the D-loop region of the mitochondrial DNA in White Leghorn and Barred Plymouth Rock chickens used in this study. The transferred donor primordial germ cell-derived cells were detected in the gonads, but not in the blood cells, of 17-d incubated embryos by PCR. 4. This procedure for primordial germ cell manipulation could provide a novel method of producing germline chimaeric chickens. 5. In conclusion, our findings indicate that primordial germ cells isolated from embryonic blood can migrate to the germinal ridges of recipient embryos after being transferred to stage X blastoderms. Although these transferred primordial germ cells differentiated into germ cells, no differentiation into blood cells was observed.     

Use of image analysis to estimate anthocyanin and UV-excited fluorescent phenolic compound levels in strawberry fruit

Strawberry is rich in anthocyanins, which are responsible for the red color, and contains several colorless phenolic compounds. Among the colorless phenolic compounds, some, such as hydroxycinammic acid derivatives, emit blue-green fluorescence when excited with ultraviolet (UV) light. Here, we investigated the effectiveness of image analyses for estimating the levels of anthocyanins and UV-excited fluorescent phenolic compounds in fruit. The fruit skin and cut surface of 12 cultivars were photographed under visible and UV light conditions; colors were evaluated based on the color components of images. The levels of anthocyanins and UV-excited fluorescent compounds in each fruit were also evaluated by spectrophotometric and high performance liquid chromatography (HPLC) analyses, respectively and relationships between these levels and the image data were investigated. Red depth of the fruits differed greatly among the cultivars and anthocyanin content was well estimated based on the color values of the cut surface images. Strong UV-excited fluorescence was observed on the cut surfaces of several cultivars, and the grayscale values of the UV-excited fluorescence images were markedly correlated with the levels of those fluorescent compounds as evaluated by HPLC analysis. These results indicate that image analyses can select promising genotypes rich in anthocyanins and fluorescent phenolic compounds.     

Three‐dimensional CT examination of the forefoot and hindfoot of the hippopotamus and tapir during a semiaquatic walking

Semiaquatic walking has resulted in the evolution of functional and morphological changes in various hoofed mammals, such as hippopotamus and Brazilian tapir. The biomechanics of skilful walking in wetlands or at the bottom of a waterbody involve the medio‐lateral opening and closing of the feet to effectively support and stabilize the body on soft ground and to reduce the water resistance during recovery stroke, respectively. We demonstrate that the opening and closing of the feet in hippopotamus and Brazilian tapir are mediated by the adduction and abduction of the most medial and lateral phalanges from the CT examination. The axial toes, metacarpals and metatarsals do not contribute to changes in the width and shape of the feet, unlike the medial and lateral toes. We suggest that this semiaquatic walking motion is derived from the original terrestrial mode of locomotion, in contrast to the highly functional swimming motion using webs or fins in morphologically modified feet and tail. From the present data we demonstrate that semiaquatic locomotion evolved due to the acquisition of adductor–abductor mobility in the phalanges of the most medial and lateral digits, as shown in hippopotamus and Brazilian tapir.     

Characteristics and Functional Properties of Ovary from Squid Loligo Formosana

The characteristics and functional properties of the ovary from Loligo formosana were studied. Moisture (72.07 ± 0.24%) was dominant, followed by protein (18.64 ± 0.51%) and carbohydrate (7.44 ± 0.2%). Ash (1.39 ± 0.03%) and lipids (0.46 ± 0.5%) were found as the minor constituents. Albumin (79.02 ± 0.79%) was the major protein of the squid ovary, followed by glutelin-1 (8.31 ± 0.62%) and globulin (6.68 ± 0.08%). Nevertheless, prolamin and glutelin-2 constituted approximately 1% of the total proteins. Based on the electrophoretic studies, albumin had the largest band intensity. The squid ovary was rich in non-essential amino acids (52.26%) and high in hydrophobic amino acids (48.03%). It was also rich in polyunsaturated fatty acid (PUFA, 43.76 ± 0.84%), followed by saturated fatty acid (SFA, 39.36 ± 0.12%) and monounsaturated fatty acid (MUFA, 12.94 ± 0.55%). Ovary lipids had a high amount of docosahexaenoic acid (C22:6) (28.59%). At pH 3, the squid ovary powder (SOP) had the maximum solubility (96.39%), whereas the lowest solubility (38.33%) was observed at pH 9. The foaming capacity and stability of SOP were increased with increasing concentration up to 8% (p < 0.05). The globulin fraction showed the higher foaming capacity, as compared to albumin and glutelin-1 fractions. The squid ovary had good nutritional value and possessed excellent foaming properties. Therefore, the squid ovary could serve as a novel food additive or ingredient.     

Vitamin contents of eggs that produce larvae showing a high survival rate in the Japanese eel Anguilla japonica

This paper describes the relationship between the egg vitamin concentrations and the egg quality in the Japanese eel Anguilla japonica . No notable relation was found between any vitamin and the fertilization rate. Hatching and survival rates of larvae, however, significantly increased with an elevated level of egg vitamin C (VC). In contrast to VC, the relation between vitamins E (VE) and A (VA) concentrations and survival rate showed a clear peak, with a reduced survival rate at both higher and lower vitamin concentrations. The ratio of VE to lipid or highly unsaturated fatty acid (HUFA) in eggs positively correlated with hatching and survival rates of larvae. High-quality (HQ) eggs were determined as eggs that produced larvae having a survival rate higher than 80% at 8 days post hatch, and low-quality (LQ) eggs were determined as eggs that did not hatch. The level of VC of HQ was significantly higher than LQ. The results of this study suggest that HQ eggs, which produce larvae having a high survival rate, must have high levels of VC and VE/HUFA ratio and contain optimum levels of VA and VE in Japanese eel.