Transgenic rice plants that over-express the mannose-binding rice lectin have enhanced resistance to rice blast

Mannose-binding rice lectin (MRL), which is almost identical to the salt-induced protein SalT, binds to mannose and glucose residues. Expression of the MRL gene in response to infection with Magnaporthe oryzae, the rice blast fungus, was stronger in the incompatible interaction than in the compatible. Transgenic rice plants that constitutively over-expressed MRL strongly suppressed the growth of invasive hyphae of the fungus on leaf sheaths and the development of typical susceptible-type lesions on leaf blades, but did not affect penetration by the fungus in comparison with the wild-type. On a polycarbonate plate, purified recombinant MRL inhibited conidial attachment and appressorium formation but not conidial germination. These results suggest that MRL may play an essential role in disease resistance by suppressing development of M. oryzae in situ.     

An expanded palette of genetically encoded Ca²⁺ indicators

Engineered fluorescent protein (FP) chimeras that modulate their fluorescence in response to changes in calcium ion (Ca(2+)) concentration are powerful tools for visualizing intracellular signaling activity. However, despite a decade of availability, the palette of single FP-based Ca(2+) indicators has remained limited to a single green hue. We have expanded this palette by developing blue, improved green, and red intensiometric indicators, as well as an emission ratiometric indicator with an 11,000% ratio change. This series enables improved single-color Ca(2+) imaging in neurons and transgenic Caenorhabditis elegans. In HeLa cells, Ca(2+) was imaged in three subcellular compartments, and, in conjunction with a cyan FP-yellow FP-based indicator, Ca(2+) and adenosine 5'-triphosphate were simultaneously imaged. This palette of indicators paints the way to a colorful new era of Ca(2+) imaging.     

Increased nuclear NAD biosynthesis and SIRT1 activation prevent axonal degeneration

Axonal degeneration is an active program of self-destruction that is observed in many physiological and pathological settings. In Wallerian degeneration slow (wlds) mice, Wallerian degeneration in response to axonal injury is delayed because of a mutation that results in overexpression of a chimeric protein (Wlds) composed of the ubiquitin assembly protein Ufd2a and the nicotinamide adenine dinucleotide (NAD) biosynthetic enzyme Nmnat1. We demonstrate that increased Nmnat activity is responsible for the axon-sparing activity of the Wlds protein. Furthermore, we demonstrate that SIRT1, a mammalian ortholog of Sir2, is the downstream effector of increased Nmnat activity that leads to axonal protection. These findings suggest that novel therapeutic strategies directed at increasing the supply of NAD and/or Sir2 activation may be effective for treatment of diseases characterized by axonopathy and neurodegeneration.     

Identification of currently cultivated Porphyra species by PCR-RFLP analysis

ABSTRACT:   Porphyra yezoensis and P. tenera are the representative species of the marine crop Porphyra (nori) in Japan. Since the two species are extremely similar to each other in morphology, nori breeders have tentatively classified many strains of cultivated Porphyra into the two species without strict species identification. In order to facilitate rapid and reliable identification of the many strains of Porphyra currently cultivated in various Japanese regions, 24 conchocelis strains were examined by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis using the plastid RuBisCo spacer and the nuclear internal transcribed spacer regions. From the results, all the strains were identified as P. yezoensis f.  narawaensis , and P. tenera was not detected. Hence, it was confirmed that most of the Porphyra strains currently cultivated in Japan are P. yezoensis f.  narawaensis , and that intensive selective breeding has led to a reduced genetic diversity in the stock used for nori cultivation.     

The effect of isoprothiolane on the emergence of infection pegs from appressoria of Pyricularia oryzae

The effect of isoprothiolane^a (di-isopropyl 1,3-dithiolan-2-ylidenemalonate), a systemic fungicide used for rice blast control, on the infection process of Pyriculuria oryzae was studied by micromanipulation in a scanning electron microscope. Whether or not infection pegs emerged from the appressoria was examined by inverting each appressorium contact surface. Infection pegs were observed on more than 80% of the appressoria, 48 h after inoculation, on both untreated rice leaves and cellophane film. Isoprothiolane, approximately 10 μg ml^?1 in the ambient water of inoculated conidia, reduced the emergence of infection pegs on rice leaves and cellophane film by 96 and 100%, respectively.     

Drug-susceptibility and isolation of a plasmid in Haemophilus (Actinobacillus) pleuropneumoniae

We isolated 56 Haemophilus (Actinobacillus) pleuropneumoniae strains from the pneumonic porcine lung tissues and tested them for antimicrobial susceptibility. Two drug-resistant strains were obtained. One, named KH-265, was resistant to streptomycin (SM) and sulfonamide (SA), and the other, named KH-195, was resistant to tetracycline (TC). The minimum inhibitory concentrations (MICs) of drugs for resistant strains were 100 micrograms/mliters for SM, 3200 micrograms/mliters for SA, and 12.5 micrograms/mliters for TC. KH-265 possessed a 8.3Kb nonconjugative plasmid, pMS260, encoding SM and SA resistance, which was transformable to E. coli strains. pMS260 belonged to none of 14 incompatibility groups including Inc. P and Inc. Q, so far tested. It was mobilizable to various causative strains for respiratory infections, Pseudomonas aeruginosa, Bordetella bronchiseptica, Pasteurella multocida and Haemophilus pleuropneumoniae, by RP4 (Inc. P) plasmid.     

Waterlogging and Hypoxia have Permanent Effects on Wheat Root Growth and Respiration

Waterlogging causes long‐lasting damage to wheat (Triticum aestivum). Root growth and respiration were investigated after heading in waterlogged, pot‐grown, wheat plants and also in hydroponically grown, wheat seedlings exposed to a hypoxic treatment. In the pot experiment, plants were subjected to 8 days of waterlogging after heading. This period of waterlogging resulted in reduced shoot and root growth through to maturity. The root CO₂ emission rates of previously waterlogged and well‐drained plants were about 220 and 140 nmol g^?1 per s, respectively, with the rate differences persisting from 10 days after anthesis through to maturity. In the hydroponic experiments, seedlings (Feekes stage 2.0) were exposed to root‐zone, hypoxic treatment for 10–19 days. The roots showed 27 % higher CO₂ emission rates and 37 % higher O₂ consumption rates, compared with untreated roots. In whole root systems, the high respiration rates found during hypoxic treatment disappeared during recovery under aerated conditions as a result of the appearance of newly initiated roots. However, measurements of the respiration of the previously hypoxic roots showed abnormally high respiration rates. In roots exposed to hypoxic treatment, total sugar concentrations were 3.6‐times higher than in untreated roots indicating that this elevation of sugar may be responsible for the continued high respiration rate. This study shows that roots exposed to waterlogging or to hypoxic treatments do not increase their weights and thus recover from the metabolic disturbances resulting from these treatments.     

Cutaneous hybrid cyst in a sprague-dawley rat

This report describes a spontaneous hybrid cyst in a Sprague-Dawley (SD) rat. A 52-week-old, male SD rat had a cutaneous cyst on the left mystacial pad. Histologically, the cyst wall showed infundibular differentiation with keratohyalin granules in the granular layer and matrical differentiation comprising basaloid epithelial cells with trichohyalin granules. The cyst cavity was filled with lamellar, flaky keratin and aggregates of shadow cells. Immunohistochemically, the infundibular-type epithelium was positive for cytokeratin (CK) AE1/AE3, CK KL1 and CK14 but negative for CK15, whereas the matrical-type epithelium was negative for all four CK isoforms examined. These immunohistochemical properties of the infundibular- and matrical-type epithelia were similar to those of the infundibulum and inferior segment of normal hair follicles, respectively. Based on these findings, the cyst was diagnosed as a hybrid cyst, comprising more than one type of cyst arising from various parts of the pilosebaceous unit.