Phenotypic Characteristics of Xanthomonas campestris pv. campestris from Nepal

Twenty strains of Xanthomonas campestris pv. campestris (Xcc) were isolated from two major crucifer-growing valleys, Chitwan and Kathmandu in Nepal and characterized by biochemical and pathogenicity tests. Strains were homogeneous in bacteriological characteristics. The ability of a strain to induce high or low disease severity index (DSI) on three host plants, broccoli, cabbage, and cauliflower, was interpreted as virulence. Strains that were associated with high or low virulence were significantly different (P>0.05). No relationship between virulence and biochemical characteristics was observed.     

Targeted identification of association between cotton fiber quality traits and microsatellite markers

Primitive and exotic accessions of cotton are potential sources of favorable alleles for genetic improvement, enriching diversity in the genetically constricted gene pool of elite cultivars. Three exotic accessions of cotton (MDN101, MDN063 and MDN257), collected from different parts of Central America and converted to day-neutral flowering; and four elite cultivars (PD94042, DES56, PMHS200 and Acala Maxxa) representing the US cotton gene pool were used as parents to create experimental populations. The corresponding F₂ and F_2:3 progenies of these populations were grown in two successive years (i.e., some in 2011–2012, some in 2012–2013) and phenotypes were scored in both F₂ and F_2:3 progenies in all 3 years (2011–2012–2013). These populations were screened with 113 polymorphic microsatellite markers selected from “hotspots” for fiber quality quantitative trait loci in the cotton genome and single marker analyses were performed to identify significant associations of the markers with six fiber quality traits. A total of 134 nominal marker-trait associations were identified, among which 15 were significant after Bonferroni correction for multiple comparisons. In 67 of 134 nominal associations and 4 of 15 significant associations, the exotic parents contributed favorable alleles to multiple backgrounds and for multiple traits, in addition to the traits for which they were selected. These results indicate that utilization of exotic and wild accessions of cotton is useful in introducing favorable alleles into the cultivated cotton gene pool for genetic improvement.     

Bioactive benzoxazinoids in rye bread are absorbed and metabolized in pigs

Recently, bioactive benzoxazinoids were discovered in cereal grains and bakery products. In this study, we studied the uptake, distribution, and metabolism of these secondary metabolites using a pig model. Twelve benzoxazinoid compounds and their 4 transformation products were quantified in the pigs' diets and biofluids using high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry. The 2-β-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DIBOA-glc) was the most dominant benzoxazinoid (232 nmol/g DM) seconded by the double-hexose derivative of DIBOA (provisionally characterized here as DIBOA-glc-hex) in the rye-based diet. DIBOA-glc (derived from the diet and intestinal deglycosylation of DIBOA-glc-hex) was apparently reduced to 2-β-D-glucopyranosyloxy-1,4-benzoxazin-3-one (HBOA-glc), the most dominant benzoxazinoid in the blood (829 nmol/L). The benzoxazinoid compounds were excreted in the urine, with HBOA-glc (18 μmol/L) as a major metabolite. In this study, we determined for the first time the bioavailability of dietary benzoxazinoids that have high digestibility, distribution, and metabolism in mammals. These findings could be a milestone for the exploitation of healthful and pharmacological properties of benzoxazinoids.     

Substrates Influence Stimulatory Effect of Mevalonic Acid on Carotenoid Production in Red Yeasts

Stimulation of carotenogenesis in carotenoid producing red yeasts, algae, or bacteria for enhanced carotenoid production has been achieved by mevalonic acid addition. Recently, carotenoid‐enriched feed was produced by Phaffia rhodozyma fermentation of inexpensive animal feeds. Because mevalonate improves carotenoid yield in P. rhodozyma in synthetic medium, this study tested whether a similar enhancement was possible in biobased substrates. Four concentrations, 0, 0.02, 0.04, and 0.1% of mevalonate as a precursor of P. rhodozyma production of astaxanthin and β‐carotene were evaluated in five substrates: defatted rice bran, full fat rice bran, wheat bran, corn whole stillage, and synthetic media. Additionally, four concentrations, 0, 0.05, 0.1, and 0.5% of apple pomace and tomato pomace were also evaluated as precursors of carotenogenesis in P. rhodozyma fermentation of corn whole stillage and rice bran. Mevalonic acid, tomato pomace, and apple pomace enhanced carotenoid yields in all substrates in that order. However, the optimal concentration of precursor and the percent increase of carotenoid yield in each substrate were variable, potentially indicating substrate influence on carotenoid stimulation. Among animal feed substrates, mevalonic acid in corn whole stillage resulted in the best astaxanthin yield of 220 μg/g and β‐carotene of 904 μg/g. Tomato pomace resulted in 29% astaxanthin and β‐carotene enhancement in corn whole stillage, and apple pomace increased β‐carotene production by 26% in whole stillage. The use of expensive mevalonate is offset by the inexpensive process of producing carotenoid‐enriched DDGS. Optimization of tomato or apple pomace addition may further enhance the carotenoid yields.     

Pork quality attributes associated with bilateral carcass variation

The objective of this study was to identify bilateral differences in pork carcass quality as influenced by single leg shackling and suspension of electrically stunned pigs. Fifty-six Genepacker x EB market barrows (118 kg) were rendered unconscious and insensible to pain via electrical stimulation. Pigs were then shackled and suspended by the right hind leg before exsanguination and remained suspended until scalding. Initial (45-min) pH values of the LM at the 10th to 11th rib interface were different (P = 0.016); shackled side loins possessed a greater i.m. pH than those loins associated with the free side of the carcass (6.26 vs. 6.10). At 24 h postmortem, loins from the shackled side had lower (P < 0.001) L* values than loins from the free side in both the sirloin (53.08 vs. 57.61) and blade (54.61 vs. 57.09) regions. Additionally, b* values were greater (P < 0.001) for loins from the shackled side than loins from the free side in the center (13.81 vs. 13.01) and blade (14.72 vs. 13.68) regions, and in the blade region, a* values were greater (P < 0.001) in the LM from the shackled side than loins from the free side (7.37 vs. 6.26). Moreover, LM chops of loins from the shackled side that were aged 21 d were rated less (P < 0.05) tough (2.74 vs. 3.95) and more (P < 0.05) juicy (4.24 vs. 3.19) than chops from the free-hanging side. However, these differences were not evident after 41 d aging. From the results of this study, it can be concluded that bilateral differences exist within the LM of a pork carcass and that these differences are likely associated with the single-leg shackling and suspension of electrically stunned pigs.     

Pathogenic and genetic diversity of Xanthomonas translucens pv. undulosa in North Dakota

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, has become more prevalent recently in North Dakota and neighboring states. From five locations in North Dakota, 226 strains of X. translucens pv. undulosa were collected and evaluated for pathogenicity and then selected strains were inoculated on a set of 12 wheat cultivars and other cereal hosts. The genetic diversity of all strains was determined using repetitive sequence-based polymerase chain reaction (rep-PCR) and insertion sequence-based (IS)-PCR. Bacterial strains were pathogenic on wheat and barley but symptom severity was greatest on wheat. Strains varied greatly in aggressiveness, and wheat cultivars also showed differential responses to several strains. The 16S ribosomal DNA sequences of the strains were identical, and distinct from those of the other Xanthomonas pathovars. Combined rep-PCR and IS-PCR data produced 213 haplotypes. Similar haplotypes were detected in more than one location. Although diversity was greatest (≈92%) among individuals within a location, statistically significant (P ≤ 0.001 or 0.05) genetic differentiation among locations was estimated, indicating geographic differentiation between pathogen populations. The results of this study provide information on the pathogen diversity in North Dakota, which will be useful to better identify and characterize resistant germplasm.     

Fiber reduction and lipid enrichment in carotenoid-enriched distillers dried grain with solubles produced by secondary fermentation of Phaffia rhodozyma and Sporobolomyces roseus

Carotenoid-enriched distillers dried grain with solubles (DDGS) developed as a value-added animal feed to provide carotenoids from mono and mixed culture (Mx) fermentation of red yeasts Phaffia rhodozyma (PR) and Sporobolomyces roseus (SR) were evaluated for their nutritional composition and compared to the control (C) DDGS. Apart from providing carotenoids, all three fermentation treatments reduced fiber with best reduction of 77% in PR, enhanced crude fat with highest of 81% in Mx, and reduced protein, amino acids and nitrogen by 50% in PR. DDGS fiber reduction by 77% was achieved by P. rhodozyma in the absence of any pretreatment. Qualitative and quantitative differences in fatty acid profiles were seen among the treatments. Vaccenic acid, a monounsaturated fatty acid produced in SR and Mx fermentation, was absent in C and PR. All these nutritional modifications are highly desirable in different DDGS-based animal feeds and can be explored to obtain tailor-made feeds/feed blends for specific animal diets.     

Effect of Cadmium and Iron on Rice (Oryza Sativa L.) Plant in Chelator-Buffered Nutrient Solution

ABSTRACT

To better understand the mechanisms responsible for differences in uptake and distribution of cadmium (Cd), nutrient-solution experiments were conducted with different varieties of rice (Oryza sativa), ‘Khitish’ and ‘CNRH3’. The plants were grown in a complete nutrient solution with different levels of pCd (-log free Cd⁺² activity) and pFe [-log free iron (Fe⁺²) activity]. The required concentrations of chelating agent and metals were determined using a computerized chemical equilibrium model such as Geochem-PC. Experimental treatments included a combination of four pCd activity levels (0, 7.9, 8.2, and 8.5) applied as Cd (NO₃)₂ 4H₂O, and two pFe activity levels (17.0 and 17.8) applied as FeCl₃. The application of both Cd and Fe in solution culture significantly affected plant growth, yield, and Cd accumulation in plant tissue. In general, yield of rice was decreased by an increase in amount of solution Cd; however, yield response varied among the cultivars. At the 7.9 pCd level, yields of rice cultivars ‘Khitish’ and ‘CNRH3’ were reduced to 69% and 65%, respectively, compared with control plants. Root Cd concentrations ranged from 2.6 mg kg^?1 (control plants) to 505.7 mg kg^?1 and were directly related to solution Cd concentrations. In rice plants, Cd toxicity symptoms resembled Fe chlorosis. Differential tolerance of varieties to phytotoxicity was not readily visible, but a significant interaction of substrate Cd and variety was obtained from dry-matter yields. Significant interactions indicated that response of tissue Cd concentration, plant Cd uptake, and translocation of Cd to the aerial parts were dependent on variety as well as substrate Cd. Uptake of Cd by roots was significantly higher than by shoots. Higher Cd uptake by rice plants decreased the uptake of other beneficial metals.

The effect of Cd and Fe on the rate of phytometallophore release was also studied in the nutrient solution. Among the rice genotypes, ‘Khitish’ was the most sensitive to Cd toxicity. In both genotypes, with the onset of visual Cd-toxicity symptoms, the release of phytometallophore (PM) was enhanced. Among the rice varieties, ‘Khitish’ had the highest rate of PM release. Treatments with the metal ions studied produced a decrease in chlorophyll and enzyme activity. A decrease in concentrations of chlorophyll pigments in the third leaf was observed due to the highest activity level of Cd (pCd 7.9). Activities of enzymes such as peroxidase (POD) and superoxide dismutase (SOD) are altered by toxic amounts of Cd. Changes in enzyme activities occurred at the lowest activity of Cd (pCd 8.5) in solution. Peroxidase activity increased in the third leaf. Results showed that in contrast with growth parameters, the measurements of enzyme activities may be included as early biomarkers in a plant bioassay to assess the phytotoxicity of Cd-contaminated solution on rice plants. Evidence that Cd uptake and translocation are genetically controlled warrants the selection of varieties that assimilate the least Cd and that translocate the least metal to the plant part to be used for human and animal consumption.     

Potential for nitrate reduction in wheat (triticum aestivum L.)

Following the prevalent agronomic practice of applying N fertilizer in two splits at optimum levels recommended for maximum yield viz. 120 kg N ha, to two wheat (Triticum aestlvum L.) cultivars, which differ in in vivo nitrate reductase (NR) activity, it was observed that the activity is high in the first formed leaf blades and declines in the successively formed ones. Enhancement in the activity subsequent to incubation of excised leaf blades in NO₃ ^‐ suggests that the substrate (NO^‐ ₃) is limiting and that the leaf blades, particularly the upper ones, have the potential to reduce additional amounts of NO₃ ^‐. High NR cultivar has greater potential than the low NR cultivar. The studies suggest that it may be possible to increase the NO₃ ^‐ moles reduced and thus enhance the reduced N content in case the nitrogen is available at later stages of growth.     

Epidemiological Investigation of Brackish Water Culture Systems in West Bengal,India

An epidemiological investigation was done in brackish water culture systems in three coastal districts of West Bengal. A total of 198 farms were randomly surveyed with a structured questionnaire. The data showed that there was a significant difference in outbreak of white spot disease (WSD) (p < 0.01), shell-associated problems (p < 0.01), and gill-associated problems (p < 0.05) among the culture systems. Among all systems, stunted and uneven growth and white fecal disease (only in shrimp monoculture) were the dominant emerging disorders. WSD remained the most prevalent disease. Some farms tested (polymerase chain reaction [PCR]) positive for WSD, but the animals were apparently healthy. Chlorination, use of PCR screening, application of immunostimulants, and strict bio-security measures play major roles in containing disease outbreaks.