Novel Identification Methods Including a Species-Specific PCR for Hazardous Bacillus Species

Fifteen strains of Bacillus spp. (three B. cereus strains, one B. subtilis, B. macerans, B. pumilus, and B. mycoides strains, and eight unknown isolates from the food-industry) were identified on species level with three designed pairs of primers for B. cereus, B. licheniformis, and B. subtilis. Primers designed for B. licheniformis (BlichF and BlichR) and B. subtilis (BsubF and BsubR) allowed specific species identification, whereas the designed pair of primers for B. cereus (BcerF2 and BcerR2) showed specificity for B. cereus sensu lato, because both B. cereus strains and B. mycoides gave positive reaction. Bacilli identification was also carried out with routine API method with unsatisfactory results. The (GTG) 5-PCR method was used for strain characterization, enabling bacilli classification into separate clusters according to their taxonomic designations

Inhibition of Clostridium Tyrobutyricum in cheese-slurry

Effects of muramidase, potassium nitrate, the mesophilic starter culture, nisin, the nisin-producing Lactococcus strain and two Lactobacillus strains with anticlostridial activity on survival and growth of the gas-producing Clostridium tyrobutyricum in a model cheese-slurry system were compared.Control cheese-slurry sample and samples with anticlostridial substances or cultures were inoculated with C. tyrobutyricum and stored at 8±1 °C in a cheese ripening cellar for 2 months. During this period spores of gas-producing clostridia were determined by the MPN method, and the presence of inoculated strains after storage was confirmed by PCR.Within the first 2 weeks potassium nitrate, muramidase and nisin had the strongest anticlostridial activity but then their effect decreased. On the other hand, effect of added cultures was observed during both months of storage. The most effective were the nisin-producing Lactococcus strain and the aroma-producing mesophilic culture — they caused a decrease in clostridial spores of about 1.5 to 2 decimal orders in comparison with the control sample at the same storage period

Голос Верхней Туры. 2014. № 02

The objective of this study was to evaluate the effect of heterosis on the lactation curve components of Girolando cattle obtained by fitting different mathematical models. Data consisted of 258,891 test day milk yield records of the first lactation from 37,965 cows of Minas Gerais State (Brazil) between 1998 and 2014. Those cows were from the Holstein breed (H), Gyr breed (G) and six genetic cross-breedings of Holstein Gyr, (1/4H, 3/4G (1/4H); 3/8H, 5/8G (3/8H); 1/2H, 1/ 2G (1/2H), 5/8H, 3/8G (5/8H); 3/4H, 1/4G (3/4H); 7/8H, 1/8G (7/8H)), which is officially named as Girolando breed in Brazil. The Wood’s linear model (WDlin), Wood’s non-linear model (WDnlin), Wilmink’s model (WL) and Ali and Schaeffer’s model (ASH) were used for estimating the peak milk yield (PY), time to peak yield (PT), 305-day milk yield (TMY) and four different persistency measures (P, P2:1, P3:1 and P3:2). Regardless of the fitted model, the highest estimates of PY and TMY were for the H group. The heterosis effect was significant (p < .001) for TMY and all components of the lactation curve, except for P2:1. Girolando cattle presented a heterosis effect of 12.30% and 13.03% for PY and TMY, respectively. The magnitude of heterosis effect was larger for PT (24.18%), whereas the different persistency measures presented the smallest magnitude of heterosis values. The producers may use the different genetic groups to benefit from the heterosis mainly for the time to peak, peak yield and 305-day milk yield

Filling the gaps in gene banks: Collecting, characterizing, and phenotyping wild banana relatives of Papua New Guinea.

International audienceSince natural habitats are disappearing fast, there is an urgent need to collect, characterize, and phenotype banana (Musa spp.) crop wild relatives to identify unique genotypes with specific traits that fill the gaps in our gene banks. We report on a collection mission in Papua New Guinea carried out in 2019. Seed containing bunches were collected from Musa peekelii ssp. angustigemma (N.W.Simmonds) Argent (3), M. schizocarpa N. W. Simmonds (4), M. balbisiana Colla (3), M. acuminata ssp. banksii (F. Muell.) Simmonds (14), M. boman Argent (3), M. ingens Simmonds (2), M. maclayi ssp. maclayi F.Muell. ex Mikl.-Maclay (1), and M. lolodensis Cheesman (1). This material, together with the seeds collected during a previous mission in 2017, form the basis for the development of a wild banana seed bank. For characterization and phenotyping, we focused on the most ubiquitous indigenous species of Papua New Guinea: M. acuminata ssp. banksii, the ancestor of most edible bananas. We calculated that the median genomic dissimilarity of the M. acuminata ssp. banksii accessions was 4% and that they differed at least 5% from accessions present in the International Transit Centre, the world's largest banana gene bank. High-throughput phenotyping revealed drought avoidance strategies with significant differences in root/shoot ratio, soil water content sensitivity, and response towards vapor pressure deficit (VPD). We deliver a proof of principle that the wild diversity is not yet fully covered in the gene banks and that wild M. acuminata ssp. banksii populations contain individuals with unique traits, useful for drought tolerance breeding programs

Sources of resistance to Pseudocercospora fijiensis

Black Sigatoka, caused by Pseudocercospora fijiensis, is one of the most devastating diseases of banana. In commercial banana‐growing systems, black Sigatoka is primarily managed by fungicides. This mode of disease management is not feasible for resource‐limited smallholder farmers. Therefore, bananas resistant to P. fijiensis provide a practical solution for managing the disease, especially under smallholder farming systems. Most banana and plantain hybrids with resistance to P. fijiensis were developed using few sources of resistance, which include Calcutta 4 and Pisang Lilin. To broaden the pool of resistance sources to P. fijiensis, 95 banana accessions were evaluated under field conditions in Sendusu, Uganda. Eleven accessions were resistant to P. fijiensis. Black Sigatoka symptoms did not progress past Stage 2 (narrow brown streaks) in the diploid accessions Pahang (AA), Pisang KRA (AA), Malaccensis 0074 (AA), Long Tavoy (AA), M.A. Truncata (AA), Tani (BB), and Balbisiana (BB), a response similar to the resistant control Calcutta 4. These accessions are potential sources of P. fijiensis resistance and banana breeding programmes can use them to broaden the genetic base for resistance to P. fijiensis