Enhanced protection against infection with transmissible gastroenteritis virus in piglets by oral co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing swine interferon-α and interleukin-18

The enhanced effect of cytokine combinations has been assessed empirically, based on their immunobiological mechanisms. However, far less is known of the enhanced protection of practical cytokine combinations against viral infection in the livestock industry, due to cost and production issues associated with mass administration. This study demonstrates the enhanced protection of oral co-administration of swine interferon-α (swIFN-α) and interleukin-18 (swIL-18) against infection with transmissible gastroenteritis virus (TGEV) in piglets using attenuated Salmonella enterica serovar Typhimurium as carrier of cytokine proteins. A single oral co-administration of S. enterica serovar Typhimurium expressing swIFN-α and swIL-18 induced enhanced alleviation of the severity of diarrhea caused by TGEV infection, compared to piglets administered S. enterica serovar Typhimurium expressing swIFN-α or swIL-18 alone. This enhancement was further observed by the reduction of TGEV shedding and replication, and the expression of IFN-stimulated gene products in the intestinal tract. The results suggest that the combined administration of the swIFN-α and swIL-18 cytokines using attenuated S. enterica serovar Typhimurium as an oral carrier provides enhanced protection against intestinal tract infection with TGEV.     

Identification and evaluation of <Emphasis Type="Italic">Forsythia</Emphasis> germplasm using molecular markers

This study identifies Forsythia germplasm and evaluated the genetic relationships of F. ×intermedia hybrids, cultivars and their putative parental species. Leaf samples of F. ×intermedia cultivars and species, such as F. koreana and F. suspensa, were collected in the Netherlands, Korea, and USA. Total genomic DNA was extracted and evaluated by randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analyses. Dendrograms were constructed by using the neighbor-joining (NJ) clustering algorithm applying the interior branch (IB) test or analyzed by STRUCTURE. In the dendrogram generated by RAPD markers, two major clusters were observed. One cluster (CL-I) contained most of the F. ×intermedia cultivars, F. suspensa, and F. koreana. The other cluster (CL-II) included F. europaea, F. ovata, F. densiflora, F. mandshurica, F. japonica, F. viridissima, and cultivars derived from F. ovata. In the AFLP dendrogram, the placement of F. ×intermedia cultivars with F. suspensa was similar, forming cluster CL-A I. The RAPD and AFLP results clearly separated most F. ×intermedia cultivars from F. ovata derived cultivars. The full range of genetic diversity of F. suspensa and F. viridissima should be investigated to verify whether these two species are truly parental taxa for F. ×intermedia. Placement of F. viridissima, F. ovata, and F. japonica in different sub-clusters requires further investigation regarding genetic diversity in the species, and their close relationship with F. koreana, F. mandshurica, and F. saxatalis.     

Source of Boron in Curcuma for Burn Symptoms at Leaf Margins

This study was initiated to investigate the source of boron (B) accumulated in margins of old leaves of Curcuma ‘Chiangmai University Pride’ (‘CMU Pride’). Nutrient elements were analyzed from different parts of the rhizome before potting and from whole rhizomes at harvest, and different leaf locations of young and old leaves during forcing in coarse sand medium. Plants were fertilized with solutions lacking B during the forcing period. Leaf-margin burn symptoms in old leaves of ‘CMU Pride’ could result from the combination of high levels of B and low total N levels. High levels of manganese (Mn) may not be involved in leaf margin-burn symptoms. Boron accumulated in the outer region of the old leaves could result from following evaporation of gutatted water droplets containing dissolved B. High levels of B in the edge of the old leaves may not be transported from the rhizomes.     

A hybrid swarm population of Pinus densiflora × P. sylvestris inferred from sequence analysis of chloroplast DNA and morphological characters

To confirm a hybrid swarm population of Pinus densiflora × P. sylvestris in Jilin, China, we used needles and seeds from P. densiflora, P. sylvestris, and P. densiflora × P. sylvestris collected from natural stands or experimental stations to study whether shoot apex morphology of 4- year old seedlings can be correlated with the sequence of a chloroplast DNA simple sequence repeat marker (cpDNA SSRs). Total genomic DNA was extracted and subjected to sequence analysis of the pine cpDNA SSR marker Pt15169. Results show that morphological characters from 4-year old seedlings did not correlate with sequence variants of this marker. Marker haplotypes from all P. sylvestris trees had a CTAT element that was absent from all sampled P. densiflora trees. However, both haplotype classes involving this insertion/deletion element were found in a P. densiflora × P. sylvestris population and its seedling progeny. It was concluded that the P. densiflora × P. sylvestris accessions sampled from Jilin, China resulted from bi-directional crosses, as evidenced by both species’ cpDNA haplotypes within the hybrid swarm population.     

Assessment of N topdressing rate at panicle initiation stage with chlorophyll meter-based diagnosis in rice

This study was conducted to determine N topdressing rate at panicle initiation stage by using chlorophyll meter (SPAD-502)-based N nutritional diagnosis in rice plant for high quality production of the Chucheongbyeo variety. Field experiments were carried for 3 years from 2003 to 2005 in Gyeonggi, Hwaseong. To confirm the method of measuring the leaf color with SPAD-502, leaf position of rice plant and measuring point on the leaf were studied. And the proper period to examine the leaf color and growth characteristics of rice plants was suggested at panicle initiation stage, from the results of the correlation between SPAD value and both content of chlorophyll and nitrogen in rice leaves. The multiply value of plant height, number of tillers per m² and SPAD value could explain well the effect of nitrogen fertilization on the growth of rice plants, and was used to determine an equation for on-site determination of nitrogen fertilization rate for Chucheongbyeo variety at the panicle initiation stage. Nitrogen fertilization increased number of tillers and rice yields, and affected the increase in protein content in rice grain resulting in loss of quality, such as taste value, and decreased the percentages of both ripened and whole rice grains. Based on the response surface statistical methodology using the SAS program, the relationship equation among protein content of brown rice (PROT), plant growth value (plant height × number of tillers × SPAD value, PGV), and nitrogen fertilization rate at the panicle formation stage (NF) was developed. That is, PROT (%) = 7.379403 ? (5.27E-7) a ? 0.013291 b + (3.025355E-13) a ² + (3.222997E-8) ab + (6.781E-05) b ², where a means PGV and b is NF (%), and the equation’s coefficient of determination (R²) was 0.967. From this equation, to recommend the optimum N fertilization rate at panicle initiation stage easily to produce high quality rice of Chucheongbyeo variety, which contains the target protein content of brown rice.     

Low-temperature pyrolysis on jute fibers as a thermochemical modification method

Low-temperature pyrolysis up to 200, 250, 300 °C was conducted in order to remove non-cellulosic compounds without damaging the structure of the cellulose in jute fibers. The chemical, morphological, and mechanical aspects of prepared low-temperature pyrolyzed jute fibers were investigated by Fourier transform infrared (FTIR) spectroscopy, the wettability test in water/dichloromethane system, moisture content measurement, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and tensile test using universal testing machine (UTM). It was confirmed that hydrophilic compounds including absorbed water, low molecular weight compounds such as waxes, hemicellulose, and lignin were largely removed from the fibers. Increasing amounts of non-cellulosic compounds were removed as the maximum pyrolysis temperature was increased. The degree of hydrophilic nature of jute fibers were reduced by low-temperature pyrolysis and thus water absorptivity of pyrolyzed jute fibers was reduced as maximum pyrolysis temperature increased. Furthermore, XRD analysis and morphological studies by SEM indicated that the crystalline structure of native cellulose was rarely damaged after pyrolysis up to 300 °C. In case of mechanical properties, breaking tenacity and breaking strain of the fibers decreased with increasing maximum pyrolysis temperatures because flaws formed on the surface of pyrolyzed jute fibers acted as weak-links. In agreement with predictions made according to Weibull’s weakest-link theory, it was found that shortened pyrolyzed jute fibers could have higher breaking tenacities compared with raw jute fibers of the same length. In addition, the compatibility with hydrophobic matrix was investigated by the mechanical properties of polypropylene (PP) reinforced with jute fibers. Consequently, it was hypothesized that low-temperature pyrolysis could be used to process raw jute fibers for use as short fiber reinforcements in fiber-polymer systems or be a simple and effective pretreatment method for a wide range of further chemical treatments.     

Epidemiological cut-off values for disc diffusion data generated by standard test protocols from <Emphasis Type="Italic">Edwardsiella tarda</Emphasis> and <Emphasis Type="Italic">Vibrio harveyi</Emphasis>

The susceptibility of 52 isolates of Edwardsiella tarda and 54 isolates of Vibrio harveyi to 12 antibiotics was established using internationally standardised disc diffusion protocols. Normalised resistance interpretation was employed to generate statistically valid epidemiological cut-off values for these susceptibility data. For three of these 24 species/antibiotic data sets, there were insufficient fully sensitive strains to allow analysis and for an additional two there were sufficient fully susceptible isolates to allow only a provisional estimate to be made. The data sets for a further two species/antibiotic combinations were considered too diverse to allow the calculation of a valid cut-off value. Valid epidemiological cut-off values were, therefore, calculated for 17 species/antibiotic combinations. It is argued that these cut-off values will greatly facilitate the performance of studies designed to monitor the consequence of antibiotic use in aquaculture. They will also facilitate the prudent and rational choice of antibiotics to be applied therapeutically in commercial farming of aquatic animals.     

Interspecific variations in seed germination of Corylopsis

This study was initiated to investigate the differences in germination percentages and rates between Corylopsis coreana Uyeki and Corylopsis sinensis var. calvescens Rehder & E.H. Wilson following a warm stratification (WS) and cold stratification (CS), and to study the effect of different WS temperatures interacting with different durations of CS. Warm stratification at 10 °C, 15 °C, 20 °C, and 25 °C was given for 1 month (1 M 10 °C, 15 °C, 20 °C, and 25 °C WS) followed by 0 M, 1 M, 2 M, and 3 M of CS at 5 °C (0 M, 1 M, 2 M, 3 M CS) and seeds were germinated in an air conditioned greenhouse maintained at 18.5 °C/18 °C. On average, less than 1% of C. coreana seeds germinated when sown without any WS and CS or with 1 M 15 °C, 20 °C, and 25 °C WS without CS treatment. However, 26% C. coreana seeds germinated after 1 M 10 °C WS without any CS treatment. Germination was not affected by WS temperatures when followed by 2 M 5 °C CS. It is concluded that C. coreana exhibited low seed germination at 10 °C and that this temperature could be considered the upper limit of CS for C. coreana. Only 2 M CS was required for more than 90% seeds to germinate. However, C. sinensis var. calvescens required longer than 3 M CS for more than 29% seeds to germinate. This clearly shows that there is an interspecific variation in optimum dormancy-breaking requirements.