Phytopythium chamaehyphon causing corm and root rot of uncultivated taro (Colocasia esculenta)

European Journal of Plant Pathology - Taro (Colocasia esculenta) is a food crop cultivated in tropical areas of the world. However, when uncultivated, taro is considered an invasive plant species...     

Study on dynamic needle thread tensions in a single needle lock stitch (SNLS) sewing machine. I. Effect of stitch length,check spring tension,fabric feed timing and needle thread in-take length

This paper, the first of a two-part series, aims to find the effect of stitch length, check spring tension, fabric feed timing and needle thread in-take length on tension peaks occurring on a spun polyester needle thread during a sewing cycle of a SNLS sewing machine. The pre-tensions on the bobbin and needle threads and sewing speed were kept constant. A PC interfaced measuring instrument was fabricated to measure dynamic sewing tension on needle thread above the needle bar. Four prominent tension peaks were detected. Longer stitch length causes higher tension peaks; and shorter length stitch requires higher pre-tension to obtain a balanced stitch. The check spring tension has no effect on tightening tension. Incorrect timing of feed dog can cause very high tightening tension. The change in the position of thread length guide alters the friction of needle thread at critical guides which determines the length of thread to be released through tensioner; release of longer length of thread results in lower tension peaks (1, 2 and 4) and vice versa.     

Interactions of nanobubbles with bovine serum albumin and papain films on gold surfaces

Nanobubbles formed on monocrystalline gold/water interface by means of the ethanol-to-water solvent exchange were exposed to the solutions of either bovine serum albumin or papain proteins. Both proteins do not change the position of nanobubbles in water, as observed by in situ tapping mode atomic force microscopy imaging before and after the introduction of the protein. The aqueous environment was subsequently replaced by ethanol. While all nanobubbles were found to dissolve in ethanol in the presence of bovine serum albumin, most of them survived when papain was employed. The protective ability of papain was ascribed to its resistance towards the protein denaturation in aqueous solutions of ethanol. The authors employed in situ atomic force nanolithography to investigate the nanomorphology of the papain/nanobubble assemblies in ethanol.     

Validation of the MAC technique in dogs and rabbits

Minimum alveolar concentrations (MAC) are determined using one of the different noxious stimuli (clamping, electrical stimulation, or surgical incision), based on a study conducted in the 1960s with three dogs. This study compares different noxious stimuli applied in a randomized order in dogs (n = 10) anesthetized with isoflurane (I) and halothane (H), and in rabbits (n = 10) anesthetized with I. Anesthesia was induced with the anesthetic in oxygen and maintained with mechanical ventilation. End‐tidal anesthetic (Fe ′A) and CO₂ (Pe ′CO₂) concentrations were monitored with a calibrated infrared gas analyzer. Pe ′CO₂ and body temperature were maintained within normal limits. Noxious stimuli included skin incision on the lateral chest (SI), clamping of the tail (TC), fore‐ (FC) and hindlimb paw (HC), and electrical current (50 V at 50 cycles second for 10 msecond pulses) applied to the fore‐ (FE) and hindlimb (HE), and oral mucosa (OE) (except rabbits). SI was applied first and only for the first two consecutive measurements using the up–down method for sequential sampling of quantal‐response data. After an initial equilibration period of at least 20 minutes at an Fe ′A of 1.4% (H) or 1.7% (I), the Fe ′A was decreased in the first animal to 0.85% of H (dog) or 1% of I (dog and rabbit) and maintained for at least 20 minutes before the noxious stimuli. If the animal responded or did not respond, the stimuli were then tested at an Fe ′A 0.1% higher or lower, respectively. The new Fe ′A was kept constant for at least 20 minutes and the noxious stimuli repeated until purposeful movement ceased or returned, respectively. MAC was defined as the Fe ′A mid‐way between the value permitting and preventing purposeful movement. Data were analyzed using an anova . MAC for I in dogs was 1.27 ± 0.047 (mean ± SEM) for TC, FC, and HC; 1.36 ± 0.035 for OE; 1.35 ± 0.040 for FE and HE; and 0.99 for SI. MAC for H in dogs was 0.97 ± 0.028 for TC; 0.96 ± 0.032 for FC and HC; 1.04 ± 0.033 for OE, FE, and HE; and 0.73 for SI. MAC for I in rabbits was 2.08 ± 0.021 for TC, FC, and HC; 2.04 ± 0.023 for FE and HE; and 0.90 for SI. MAC for SI was significantly lower than the other methods. In conclusion, electrical current and clamping resulted in similar MAC values.     

Habitat use by two extremophile,highly endemic,and critically endangered fish species (Gambusia eurystoma and Poecilia sulphuraria; Poeciliidae)

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Characterization of Salmonella enterica serovar Typhimurium strains of veterinary origin by molecular typing methods

Twenty-eight strains of Salmonella enterica serovar Typhimurium were characterized by three PCR-based methods. Ten strains harbored type I integrons and two different integron profiles were detected. Typing by amplified fragment length polymorphism (AFLP) resulted in observation of 10 profiles that differed by one to six bands. Salmonella strains were screened for presence of phage genes using a PCR-phage typing; five genes from P22 phage and genes encoding putative virulence factors from phages Gifsy-1, Gifsy-2 and Fels-1 were selected for testing. This set of genes was sufficient for dividing the strains into eight different PCR-phage profiles. Similar grouping of strains was observed in case of all the employed DNA techniques and they corresponded well with the phage type and antimicrobial resistance of the strains. The highest discriminating power was achieved with use of the AFLP, yet the detection of integrons and PCR-phage typing also proved to be valuable in typing the S. Typhimurium strains.     

First report of Lasiodiplodia theobromae and Fusarium proliferatum causing teak die back in Costa Rica

Teak plantation productivity and economic value have risen significantly since 2000; however, teak dieback syndrome in commercial plantations is becoming worse every year. We isolated, characterized and identified the causal agents of teak dieback, based on morphological characteristics in culture and DNA sequencing. The pathogenicity of Lasiodiplodia theobromae and Fusarium proliferatum (separate and together) was confirmed in inoculations of teak elite genotypes, fulfilling Koch's postulates. To our knowledge, this is the first report of L. theobromae and F. proliferatumcausing teak dieback syndrome in Costa Rica.     

Screenhouse performance of VAM-inoculated seedlings of Leucaena leucocephala (Lam.) De wit. in a phosphorus-deficient and aluminum sulfate-treated medium

The effect of 3 species of vesicular-arbuscular mycorrhizal (VAM) fungi on the growth of Leucaena leucocephala (Lam.) De Wit. in a phosphorus-deficient and aluminumsulfate (AIS)-treated medium was investigated in a screenhouse experiment. Plant height, root length, nodulation, phosphorus uptake and nitrogen fixation were used as indices of plant performance.While there were significant differences among mycorrhizal plants with respect to these indices, they outperformed their non-mycorrhizal counterparts in all respects except in nitrogen content. Of the 3 mycorrhizal species studied, Glomus etunicatum (Becker and Gerd) was the most efficient, followed by Glomus fasciculatum (Thaxter) Gerd and Trappe, and finally, Gigaspora margarita (Becker and Hall). Both aluminumsulfate and mycorrhizal treatments increased shoot dry weight.     

Conifer expansion reduces the competitive ability and herbivore defense of aspen by modifying light environment and soil chemistry

Disturbance patterns strongly influence plant community structure. What remains less clear, particularly at a mechanistic level, is how changes in disturbance cycles alter successional outcomes in plant communities. There is evidence that fire suppression is resulting in longer fire return intervals in subalpine forests and that these lengthened intervals increase competitive interactions between aspen and conifer species. We conducted a field and greenhouse study to compare photosynthesis, growth and defense responses of quaking aspen and subalpine fir regeneration under light reductions and shifts in soil chemistry that occur as conifers increase in dominance. The studies demonstrated that aspen regeneration was substantially more sensitive to light and soil resource limitations than that of subalpine fir. For aspen, light reductions and/or shifts in soil chemistry limited height growth, biomass gain, photosynthesis and the production of defense compounds (phenolic glycosides and condensed tannins). Biomass gain and phenolic glycoside concentrations were co-limited by light reduction and changes in soil chemistry. In contrast, subalpine fir seedlings tended to be more tolerant of low light conditions and showed no sensitivity to changes in soil chemistry. Unlike aspen, subalpine fir increased its root to shoot ratio on conifer soils, which may partially explain its maintenance of growth and defense. The results suggest that increasing dominance of conifers in subalpine forests alters light conditions and soil chemistry in a way that places greater physiological and growth constraints on aspen than subalpine fir, with a likely outcome being more successful recruitment of conifers and losses in aspen cover.