Genetic characterisation and analysis of infectious bronchitis virus isolated from Brazilian flocks between 2010 and 2015

1. Infectious bronchitis virus (IBV) variants in Brazil were isolated during 2010–2015 for epidemiological and molecular analysis to characterise the different variants and perform a bioinformatic analysis to compare with sequences of variants collected over the previous 40 years.

2. Of the 453 samples examined, 61.4% were positive for IBV and 75.9% of these were considered to have the BR-I genotype and were detected in birds of all ages distributed in all five Brazilian regions.

3. The ratio of non-synonymous substitutions per non-synonymous site (dN) to synonymous substitutions per synonymous site (dS), i.e. dN/dS, revealed a predominance of codons with non-synonymous substitutions in the first third of the S1 gene and a dN/dS ratio of 0.67. Additionally, prediction of N-glycosylation sites showed that most of the BR-I variants (from 2003 to early 2014) had an extra site at amino acid position 20, whereas the newest variants lacked this extra site.

4. These results suggest that Brazilian IBV variants probably underwent drastic mutations at various points between 1983 and 2003 and that the selection processes became silent after achieving a sufficiently effective antigenic structure for invasion and replication in their hosts. Brazilian IBV genotype BR-I is currently the predominant genotype circulating in Brazil and South America.     

Immunological characterization of Mycoplasma hyopneumoniae recombinant proteins

Mycoplasma hyopneumoniae, the primary pathogen of enzootic pneumonia, is highly prevalent worldwide and causes major economic losses to the pig industry. Commercial vaccines are widely used in the control of this disease, however, they provide only partial protection. The aim of this study was to evaluate 34 recombinant proteins of M. hyopneumoniae expressed in Escherichia coli. Antigenic and immunogenic properties of these proteins were analyzed. For this, the proteins were tested against hyperimmune and convalescent pig sera through ELISA and Western blot. Immunogenicity of the recombinant proteins was evaluated in BALB/c mice following intramuscular inoculation. Most antigens were able to induce a strong immune response and sera from inoculated mice were able to recognize native proteins by cell ELISA and Western blot. Several recombinant proteins were specifically recognized by convalescent pig sera, indicating they are expressed during infection. These data may help to develop more efficacious vaccines against M. hyopneumoniae.     

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Fish and piscivorous bird eggs collected in 2003 from Lake Maggiore (Italy), were analysed for PCB and DDT contamination. Lake Maggiore has been severely polluted by DDT through production of the pesticide within its catchment. Although agricultural application of DDT was banned in Italy in the 1978, industrial production continued until 1996, with enough contamination of water and soil for serious bioaccumulation in the lake biota. PCB and DDT concentrations in a whitefish (Coregonus macrophthalmus Nusslin 1882) were seen to be dependent on season and fish age, but not on sex. The average increase of the lipid-normalised concentration of DDTs and PCBs was two-fold across season and also across age, resulting in an overall increase of four fold. The seasonal variation was related to the eco-physiological cycle of the fish and to the contamination dynamic of the lake, while the effect of the fish age was explained on the base of biomagnification-related mechanisms. A fugacity model was applied to predict the age-dependent bioaccumulation potential of PCBs, whose concentrations were rather stable in recent years in the lake. Predicted values for compounds with negligible biotransformation were in good agreement with experimental data (calculated vs. experimental mean difference of 14%), and a relationship between the increase of experimental age-dependent concentration and K _ow was observed. The good correspondence between the predicted and the measured values for most PCB congeners confirmed the general inability of fishes to biotransform these compounds. On the contrary, the importance of biotransformation processes was recognised in birds; eggs of a fish eating bird (Podiceps cristatus) from the same area selectively bioaccumulated p,p′-DDE. For PCBs, congener 149 appears to be completely metabolized by the bird species, and congeners 95, 101, 132, 151 and 174 were reduced as well. The role of the meta–para free position on at least one phenyl ring of PCB congeners in biotransformation processes was confirmed.     

Attack and defense movements involved in the interaction of <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis> and <Emphasis Type="Italic">Helicoverpa zea</Emphasis> (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J. E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are among the main pests of maize. Both species exhibit cannibalistic behavior and quite often share the same feeding guild in maize (maize ears), which can result in several interspecific and intraspecific interactions. Paired interaction scenarios of intraspecific and interspecific larvae were assessed in arenas in the presence and absence of food to characterize movements resulting from interactions of these insects. There was a difference in the frequency of behavioral movements in all the interactions, except for S. frugiperda in the presence of food. Head touching and recoiling were the predominant movements in most of the interaction scenarios. Spodoptera frugiperda exhibited a predominance of defensive movements when competing against H. zea in the same instars. Cannibalism and predation occurred frequently in interactions involving 6th instar of H. zea against opponents in 4th instar. Larvae of H. zea show a higher aggressive movement than S. frugiperda. The larvae of S. frugiperda take advantage during the interactions, although they present more defensive movements compared to H. zea. This study provides relevant information regarding the interaction of these species and intraguild interaction, which might influence the population dynamics and the competitive displacement of pest species that share the same ecological niche.     

Genetic improvement of processing tomatoes: A 20 years perspective

Over the past 20 years replicated field trials have been conducted on processing tomato varieties by the California Tomato Research Institute and the Israeli Ministry of Agriculture with the objective of identifying superior varieties. Because common check varieties were included in consecutive years, environmental effects could be factored out allowing an estimate of the genetic improvement due to breeding. The results indicate an average genetic gain for yield of 1.54%/yr for California and of 0.4%/yr for Israel. No significant genetic gain in brix was found for California, whereas for Israel, the data indicate an average increase of 0.53%/yr. For the derived trait brix × yield, the overall genetic gain ranged from 0.9%/yr in Israel to 1.5%/yr in California. A significant genetic gain of 1.15%/yr was determined for fruit color in California for the period 1977–87 and of 2.73%/yr for Israel during the years 1985–1995. The improvement in yield is partially due to the increase in the proportion of hybrids in the trials starting from the mid 1980's. The implications of the results for future tomato breeding are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

An Aboriginal Australian genome reveals separate human dispersals into Asia

We present an Aboriginal Australian genomic sequence obtained from a 100-year-old lock of hair donated by an Aboriginal man from southern Western Australia in the early 20th century. We detect no evidence of European admixture and estimate contamination levels to be below 0.5%. We show that Aboriginal Australians are descendants of an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago. This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago. We also find evidence of gene flow between populations of the two dispersal waves prior to the divergence of Native Americans from modern Asian ancestors. Our findings support the hypothesis that present-day Aboriginal Australians descend from the earliest humans to occupy Australia, likely representing one of the oldest continuous populations outside Africa.