Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development

The cell lineages that form the transporting tissues (xylem and phloem) and the intervening pluripotent procambial tissue originate from stem cells near the root tip. We demonstrate that in Arabidopsis, cytokinin phytohormones negatively regulate protoxylem specification. AHP6, an inhibitory pseudophosphotransfer protein, counteracts cytokinin signaling, allowing protoxylem formation. Conversely, cytokinin signaling negatively regulates the spatial domain of AHP6 expression. Thus, by controlling the identity of cell lineages, the reciprocal interaction of cytokinin signaling and its spatially specific modulator regulates proliferation and differentiation of cell lineages during vascular development, demonstrating a previously unrecognized regulatory circuit underlying meristem organization.     

Systemic nematicidal activity of fluensulfone against the root-knot nematode Meloidogyne incognita on pepper

BACKGROUND: Fluensulfone, a new nematicide of the fluoroalkenyl group, has proved to be very effective in controlling root‐knot nematodes, Meloidogyne spp., by soil application. The systemic activity of this compound against M. incognita on peppers via soil drenching and foliar spray was evaluated. RESULTS: Root application of fluensulfone via soil drenching showed slight and no nematode control activity when applied 4 and 10 days, respectively, after inoculation. A single foliar spray of peppers with a fluensulfone solution at 3.0 g L^?1 prior to inoculation reduced the galling index by 80% and the number of nematode eggs by 73–82% of controls. The reduction in these parameters by fluensulfone was much higher than that obtained with oxamyl or fenamiphos at the same concentration. This activity was also observed when the plants were sprayed 21 days before inoculation. A series of experiments suggested that foliar spray with fluensulfone prior to inoculation reduces nematode invasion. However, foliar spray after inoculation did not inhibit nematode development inside roots. CONCLUSION: Fluensulfone showed relatively high nematode control activity when sprayed on the foliage before inoculation. Fluensulfone may be used as a foliar application, in addition to soil application, for root‐knot nematode control. Copyright © 2011 Society of Chemical Industry     

Phakopsora montana, another grapevine leaf rust pathogen in Japan

A new grapevine leaf rust (GLR) was found to be caused by Phakopsora montana. This new fungus naturally infects Crimson Glory vine (Vitis coignetiae), forming uredinia and telia on the leaves. Under experimental conditions, the fungus was pathogenic to table grape cultivars Delaware and Kyoho (V.?×?labruscana), Amur River grape (V. amurensis), and V. ficifolia, on which it produced urediniospores. Inoculation experiments proved that the pathogen alternates hosts, forming spermogonia and aecia on Meliosma tenuis. The new pathogen resembles P. meliosmae-myrianthae (=P. euvitis), a common GLR fungus; however, its spermogonial/aecial stage is restricted to M. tenuis, contrary to P. meliosmae-myrianthae with its spermogonial/aecial stage restricted to M. myriantha. Aeciospores of the new pathogen are evenly thin-walled, whereas the aeciospore wall is conspicuously thickened apically in P. meliosmae-myrianthae. Phakopsora montana is known to occur only on V. coignetiae in nature; however, table grape cultivars Delaware and Kyoho were not resistant to P. montana under experimental conditions. These results indicate that P. montana has caused a certain proportion of the GLR disease recorded in Japan with a possible mixed infection with P. meliosmae-myrianthae.     

Detection of carrot red leaf virus-RNA in carrot seeds by multiplex RT-nested PCR

A practical method to detect carrot red leaf virus (CtRLV)-RNA in carrot seeds using a multiplex RT-nested PCR was developed. Total RNA was extracted from carrot seeds by the guanidine thiocyanate method. RT-PCR was performed with a one step RT-PCR kit with CtRLV primers and carrot ubiquitin primers for the internal control, and the second PCR was performed with CtRLV nested primers. Ubiquitin were detected by the first PCR in all samples, while distinct CtRLV-RNA was detected by the 2nd PCR. CtRLV-RNA was detected from carrot seeds from three cultivars. The multiplex RT-nested PCR method was able to detect CtRLV-RNA from a single carrot seed.     

Nematicidal activity of the leaf powder and extracts of Myrtus communis against the root‐knot nematode Meloidogyne javanica

Nematicidal activity of the leaf powder, leaf extracts and formulated leaf extracts of Myrtus communis, an evergreen shrub that is widely distributed in Israel and other Mediterranean countries, was evaluated using the root‐knot nematode Meloidogyne javanica in in vitro and pot experiments. Leaf powder added to sand at 0·1% (w/w) reduced the number of juveniles recovered from the sand by more than 50%. Reduction in galling index and number of nematode eggs on tomato roots was also observed by incorporating the leaf powder at 0·1–0·4% (w/w) in the soil in pot experiments. Leaf powder extracts with methanol or ethanol showed the highest nematicidal activity among all extracts tested. Emulsifiable concentrates of leaf‐paste extract at a concentration as low as 0·005% (a.i., w/w) reduced the number of juveniles recovered from treated sand and the gall index of cucumber seedlings. The extract paste at 26 g m^?2 was also effective in reducing the gall index of tomato plants in field‐plot experiments. The leaf powder at 0·2% and the formulated leaf‐paste extract at 0·02% were also nematicidal to Tylenchulus semipenetrans and Ditylenchus dipsaci, but not to Pratylenchus penetrans or Steinernema feltiae. At least three nematicidal compounds were found in the leaf extract upon fractionation by thin‐layer chromatography. The results suggest that the leaf powder and paste extract of M. communis are potential nematicides against root‐knot nematodes.     

Concentrations of cartilage oligomeric matrix protein in dogs with naturally developing and experimentally induced arthropathy

OBJECTIVE: To assay concentrations of cartilage oligomeric matrix protein (COMP) in canine sera and synovial fluid (SF), to compare COMP concentrations in clinically normal dogs and dogs with joint disease, and to analyze changes in COMP concentrations in dogs with experimentally induced acute synovitis. ANIMALS: 69 control dogs without joint disease, 23 dogs with naturally occurring aseptic arthropathy, and 6 dogs with experimentally induced synovitis. PROCEDURE: Serum (n = 69) and SF (36) were obtained from control dogs. Samples of serum (n = 23) and SF (13) were obtained from dogs with naturally occurring aseptic arthropathy with or without radiographic features of osteoarthritis (OA). Serum and SF were obtained before and 1, 2, 3, and 7 days after induction of synovitis. The COMP concentrations were determined by use of an inhibition ELISA that had canine cartilage COMP and monoclonal antibody against human COMP. RESULTS: Concentrations of COMP in serum and SF of control dogs were 31.3+/-15.3 and 298.7+/-124.7 microg/ml, respectively. In naturally occurring OA, COMP concentrations in serum (44.9+/-177 microg/ml) and SF (401.7+/-74.3 microg/ml) were significantly higher than corresponding concentrations in control dogs. The COMP concentration in SF peaked 24 and 48 hours after induction of synovitis, whereas concentration in serum peaked on day 3. CONCLUSIONS AND CLINICAL RELEVANCE: These results supported the hypothesis that COMP concentration in serum and SF of dogs may be altered after cartilage degradation or synovitis. Measurement of COMP concentrations can be useful when differentiating arthropathies in dogs.     

Comparison of the cardiovascular effects of intracellular cyclic adenosine 3',5'-monophosphate (cAMP)-modulating agents in isoflurane-anesthetized cats

The inotropic, chronotropic, and vasodilatory effects of five commonly used cyclic adenosine 3',5'-monophosphate (cAMP)-modulating agents were evaluated. Hemodynamic functions were measured continuously in isoflurane-anesthetized cats during infusion of the following: dobutamine (DOB; 2.5, 5 and 10 microg/kg/min; n=8), dopamine (DOP; 1.25, 2.5, 5 and 10 microg/kg/min; n=5), milrinone (MIL; 2.5, 5 and 10 microg/kg/min; n=8), 6-(3-dimethyl-aminopropionyl) forskolin hydrochloride (COL; 0.2, 0.4, 0.8, and 1.6 microg/kg/min; n=7), and bucladesine sodium (BUC; 10, 20, and 40 microg/kg/min; n=9). At the highest infusion rate, DOB and DOP produced the greatest positive inotropic (increase in left ventricular (LV) dP/dt = 89 +/- 4% and 75 +/- 6%, respectively) and chronotropic (increase in heart rate (HR) = 42 +/- 4% and 22 +/- 6%, respectively) effects. MIL and COL produced similar albeit less pronounced positive inotropic (increase in LV dP/dt = 18 +/- 3% and 22 +/- 6%, respectively) and chronotropic (increase in HR = 13 +/- 4% and 21 +/- 4%, respectively) effects. Both also had significant vasodilatory effects (decrease in peripheral resistance (PR) = -30 +/- 2% and -35 +/- 7%, respectively). In contrast, BUC produced only vasodilatation (decrease in PR = -33 +/- 6%). Hence, MIL, COL, and BUC had significant vasodilatory effects and less-pronounced inotropic effects than the catecholamines DOB and DOP. The vasodilatory effects of non-catecholamine drugs for treatment of congestive heart failure should translate into beneficial decreases in both pre-load and after-load. In contrast, the strong inotropic effects of DOB and DOP should be beneficial in the treatment of acute heart failure and anesthetic crisis.     

Characterization of the 16S-23S rRNA intergenic spacer regions among strains of the Fusobacterium necrophorum cluster

The 16S-23S rRNA intergenic spacer regions (ISRs) of Fusobacterium necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme were characterized. Products of two sizes, about 360 bp (small) and 530 bp (large), were generated by PCR amplification from the 16S-23S rRNA ISR of all the strains tested. The large and small 16S-23S rRNA ISRs of F. necrophorum exhibited a level of sequence similarity of 93.9% to 99.7% and 94.2% to 98.6% homologies within the species, respectively. Only the large spacer regions in these bacteria contained one or two tRNA genes. F. necrophorum subsp. necrophorum contains the isoleucine and alanine tRNA gene, whereas F. necrophorum subsp. funduliforme contains the isoleucine tRNA gene.     

Serum leptin levels during the periparturient period in cows

Serum leptin concentrations were measured in antenatal and postnatal cows housed at two different locations. The mean serum leptin concentration was 9.2 +/- 0.6 ng/m l (n=22) in one group, and was slightly lower in the other (7.4 +/- 0.4 ng/ml, n=54), probably because of the different nutritional conditions between the two groups. There was no consistent variation in relation to the menstrual cycle and the periparturient period in both groups. Moreover, serum leptin concentrations during the periparturient period were independent of the number of delivery and the incidence of mastitis and milk fever. These results are quite different from those in rodents and human, suggesting the different regulatory mechanism of circulating leptin concentration in cows.