Availability and plant uptake of nutrients following the application of paper pulp and lime to tropical acid soils

Availability and plant uptake of nutrients were evaluated in three tropical acid soils (Kandiudult) amended with paper pulp and lime under greenhouse conditions. Amendments were applied to attain target pH values of 5.5, 6.0, and 6.5. A control treatment (no paper pulp or lime added) was also included. Rye grass (Lolium perenne L.) as a test plant was grown for three successive cycles of 40 days each. Extractable nutrients and cumulative nutrient uptake were determined. The application of paper pulp or lime resulted in a significant increase in exchangeable Ca and K and a decrease in exchangeable Mg and extractable Fe, Mn, and Zn. Amendment of soils with paper pulp or lime increased plant uptake of Ca and Mg and decreased that of K, Mn, and Zn. Both amendments behaved similarly, but the effect of lime seemed generally greater than that of paper pulp. Paper pulp in tropical acid soils behaved as a liming agent rather than an organic amendment. Similar to lime, amendment of soils with paper pulp resulted in an increase in availability of Ca and Mg and in a decrease in availability of K, Mn, and Zn for plants. Soil extractions appeared to be appropriate for assessing the availability of Ca, Mn, and Zn. Soil pH and effective cation exchange capacity positively influenced the availability of Ca and negatively the availability of Mn and Zn. Thus, the precision of predicting nutrient availability in paper pulp amended tropical acid soils could be improved by including soil pH or effective cation exchange capacity in relevant regression equations.     

Susceptibility of chicks to infectious bursal disease (IBD) following vaccination of their parents with live IBD vaccine.

Vaccination of parent chickens with a commercial live infectious bursal disease (IBD) vaccine under field conditions at varying ages and by different routes resulted in variable susceptibility to the disease in their chicks. There was little correlation between the methods of vaccination and the levels of immunity in the chicks. There was some evidence that levels of transferred immunity decreased with the age of the parents. Of five flocks examined, the onset of susceptibility to IBD occurred at two days of age in two flocks and about one week of age in the other three. Four flocks were completely susceptible by the 27th day, the other at 31 days. Precipitins were demonstrated at day old in 100 per cent of chicks in three flocks and in 80 per cent in the other two. The precipitins had disappeared in all flocks by 17 days of age.     

Prevalence of parasite eggs and cysts in faeces from dairy cows in Colombia

Summary When 1, 711 bovine faecal samples from 113 farms in eight dairy areas of Colombia were examined for the presence of helminth eggsFasciola hepatica eggs were found in the faeces from 60% of the farms and samples from animals kept above 2,000 m. Strongyle eggs were found in faeces from 82% of the farms and in 18% of the samples.

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Resumen Se examinaron 1.711 muestras fecales provenientes de 113 fincas, localizadas en ocho zonas lecheras de Colombia. Se encontraron huevos deFasciola hapatica, en el 60% de fincas y muestras fecales de animales sobre los 2,000 m.s.n.m. Se encontraron tambien huevos de estrogilideos en heces del 82% de fincas y en el 18% de las muestras examinadas.

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Résumé La recherche d’oeufs d’helminthes sur 1711 échantillons de fécès provenant de 113 fermes de 8 districts laitiers de Colombie a permis de noter la présence d’oeufs deFasciola hepatica dans 60 p. 100 des fermes et échantillons originaires d’animaux vivant à plus de 2,000 m. Des oeufs de strongles ont été notés dans les fécès provenant de 82 p. 100 des fermes et 18 p. 100 des échantillons.

     

Promoter anchored amplified polymorphism based on random amplified polymorphic DNA (PAAP-RAPD) in cotton

Non-coding sequences account for a majority of the higher plant genome, some of which have important effects in gene regulation and plant development. In an effort to develop molecular marker systems to search for polymorphisms associated with high fiber yield and quality in cotton, we have developed a methodology that could specifically target the regulatory regions of the cotton genome. In this study we designed 10-nucleotide degenerate promoter primers based on conserved core promoter sequences and tested their applicability in PCR amplifications in combination with 10-mer random amplified polymorphic DNA (RAPD) primers. The amplified markers are called promoter anchored amplified polymorphism based on RAPD (PAAP-RAPD). Forty cotton genotypes with diverse genetic and geographical backgrounds were used to test the PAAP-RAPD system using polyacrylamide gel electrophoresis. Based on PAAP-RAPD markers amplified from 12 primer combinations, the 40 genotypes were classified into five distinctive groups: two Upland cotton (Gossypium hirsutum) groups from China, another two Upland cotton groups from the USA, and one group from American Pima cotton (G. barbadense). The groupings are in general consistent with their genetic and geographical origins. Thirty-six PAAP-RAPD and RAPD fragments were cloned and four of them were further subjected to sequence analysis. Signal scanning using software PLACE confirmed that they contained an array of cis-regulatory sequences in addition to the core promoter sequences. The results demonstrate the potential application of PAAP-RAPD as a new marker system specifically targeting regulatory regions of the plant genome.     

20th-century industrial black carbon emissions altered Arctic climate forcing

Black carbon (BC) from biomass and fossil fuel combustion alters chemical and physical properties of the atmosphere and snow albedo, yet little is known about its emission or deposition histories. Measurements of BC, vanillic acid, and non-sea-salt sulfur in ice cores indicate that sources and concentrations of BC in Greenland precipitation varied greatly since 1788 as a result of boreal forest fires and industrial activities. Beginning about 1850, industrial emissions resulted in a sevenfold increase in ice-core BC concentrations, with most change occurring in winter. BC concentrations after about 1951 were lower but increasing. At its maximum from 1906 to 1910, estimated surface climate forcing in early summer from BC in Arctic snow was about 3 watts per square meter, which is eight times the typical preindustrial forcing value.     

Evaluation of reproductive traits in Bos taurus and Bos indicus crossbred heifers: effects of postweaning energy manipulation

Reproductive traits were evaluated in Bos taurus and Bos indicus crossbred heifers that were fed different diets during the postweaning period. The study was designed in a 2 x 2 x 2 factorial arrangement of treatments. Angus x Hereford (AH; n = 148) and Brahman x Hereford (BH; n = 148) heifers were sorted after weaning by body weight into light (LW) and heavy (HW) weight blocks. Heifers in each weight block were assigned to diets calculated to reach a target weight of 55% (LE) or 65% (HE) of their projected mature weights by the start of the breeding season. Puberty was determined after a 160-d observation period and characterized by the following criteria: 1) behavioral estrus, 2) presence of a palpable corpus luteum (d 6 to 10; estrus = d 0), and 3) rise in serum progesterone above 1 ng/ml (d 6 to 10). A higher (P = .01) proportion of AH heifers than of BH heifers reached puberty by the breeding season (93% vs 67%). Interactions of breed x weight block and energy level x weight block also contributed to this difference. Weight at puberty was heavier (P = .001) among HE than among LE heifers and greater for heifers in HW than for those in LW blocks (P = .02). Differences in prebreeding weight, body condition, average daily gain, hip height, and pelvic area were influenced selectively by breed, energy level, or weight block. Pregnancy rates were higher (P = .01) among AH than among BH heifers. Incidence and severity of dystocia was influenced by the breed x energy level interaction (P = .01). Brahman x Hereford heifers had less (P = .01) dystocia than AH heifers, HE heifers had less (P less than .02) dystocia than LE heifers, and HE-AH heifers had less (P less than .01) dystocia than LE-AH contemporaries. Subsequent duration of the postpartum interval to estrus was shorter (P = .002) among AH than among BH females. Pregnancy rates at the end of the 2nd yr were higher (P = .02) among LW than among HW females and weights were heavier (P = .001) at weaning among calves weaned from BH dams.     

Biofilm bacteria: formation and comparative susceptibility to antibiotics

The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of microcolonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms.     

Fibroblast growth factor-10 maintains the survival and promotes the growth of cultured goat preantral follicles

The aim of the present study was to investigate the effects of fibroblast growth factor-10 (FGF-10) on the survival, activation (transition from primordial to primary follicles), and growth of goat preantral follicles cultured in vitro. Pieces of ovarian cortex were cultured for 1 and 7 d in the absence or presence of FGF-10 (0, 1, 10, 50, 100, and 200 ng/mL). Noncultured and cultured tissues were processed and analyzed by histology, transmission electron microscopy, and viability testing. Results showed that after 7 d, a greater percentage (79.9%) of morphologically normal follicles (containing an oocyte with regular shape and uniform cytoplasm, and organized layers of granulosa cells without a pyknotic nucleus) was observed when cultured with 50 ng/mL of FGF-10 when compared with other concentrations of FGF-10 (0 ng/mL, 67.3%; 1 ng/mL, 68.2%; 10 ng/mL, 63.3%; 100 ng/mL, 64.4%; 200 ng/mL, 52.7%). Ultrastructural analyses and viability testing using fluorescent markers confirmed the follicular integrity of FGF-10 (50 ng/mL)-treated fragments after 7 d of culture. After 7 d, all FGF-10 concentrations reduced the percentage of primordial follicles and increased the percentage of developing follicles. In the presence of 50 ng/mL of FGF-10, follicles increased in diameter after 7 d of culture when compared with other concentrations tested. In conclusion, this study demonstrates that FGF-10 maintains the morphological integrity of goat preantral follicles and stimulates the growth of activated follicles in culture. The culture conditions identified here contribute to the understanding of the factors involved in goat early follicular development.