Calving date and its variability as a potential trait in the breeding objective to account for reproductive seasonality in alpacas

The low fertility and offspring survival indicators in alpacas can be partially due to their particularity seasonal reproduction that reduces the opportunities of the females to become pregnant within a season, with the survival of the offspring concerned by the availability of food and exposure to diseases that depends on the calving date. Optimizing the date of delivery and reducing its variability are shown as eligible criteria that could be used as selection criteria within the genetic improvement programmes in alpacas, the calving date being a much more appropriate trait to measure and optimize fertility unlike of age at first calving and the calving interval, this due to the reproductive seasonality in camelids. For this study, 6,533 birth date records were taken between 2001 and 2018 of Peruvian alpacas, to estimate the genetic parameters. Models assuming heterogeneity in the residuals were fitted besides classical homogeneous models to address, not only the possibility of forwarding or delaying the calving date, but also the trend to have parturitions in similar dates. The heritability and repeatability ranged from 0.07 to 0.20 for a homogeneity model and from 0.08 to 0.23 for a heterogeneity model, and suggest the possibility of advancing or delaying the calving date. It should be taken into account that the gestation length of camelids makes it difficult to adapt many reproductive traits, and trying to centre the calving date could delay it. It was concluded the feasibility to genetically select the calving date, also in the production of camels and dromedaries, which have the same reproductive characteristics as alpacas. This selection can be combined with other traits. The heterogeneity model was shown to provide a better fit.     

Investigations on the prevalence and potential pathogenicity of intestinal trichomonads in pigs using in situ hybridization

In pigs, three different trichomonad species (Tritrichomonas foetus, Tetratrichomonas buttreyi and Tritrichomonas rotunda) have been described as commensals in the large intestine. The aim of this study was to gain further knowledge on the prevalence and pathogenicity of trichomonads in pigs by using a morphology-based approach. Chromogenic in situ hybridization (ISH) is a technique which allows direct localization of the protozoa in the intestinal tissue and correlation of the infection with pathologic changes. In the present study paraffin-wax embedded colon and ileum samples of 192 pigs were analyzed with this method. Using a probe specific for all known members of the order Trichomonadida (OT) 100 of the 192 pigs were tested positive. Thereof, about 10% showed moderate to high-grade parasitic load with trichomonads invading the lamina propria. Partial 18S ribosomal RNA gene sequencing of six of those animals showed a 100% sequence identity with T. foetus sequences. The majority of these animals were also tested positive for other enteropathogenic agents, such as Brachyspira sp., Lawsonia intracellularis, Escherichia coli, and porcine circovirus type 2. All OT-positive samples were further examined with another probe complementary to all known Tritrichomonas species sequences including T. foetus, T. augusta, T. mobilensis and T. nonconforma resulting in only 48 positives. These results suggest that T. foetus may not only be considered as an intestinal commensal but rather a facultative pathogen of pigs with a tendency for tissue invasion in the presence of other agents. Furthermore, the existence of other - yet to be identified - trichomonad species in the colon of pigs was shown.     

Compositional changes in 'Bartlett' pear ( Pyrus communis L.) cell wall polysaccharides as affected by sunlight conditions

Preharvest conditions can have a great impact on fruit quality attributes and postharvest responses. Firmness is an important quality attribute in pear, and excessive softening increases susceptibility to bruising and decay, thus limiting fruit postharvest life. Textural characteristics of fruits are determined at least in part by cell wall structure and disassembly. Few studies have analyzed the influence of fruit preharvest environment in softening, cell wall composition, and degradation. In the current work 'Bartlett' pears grown either facing the sun (S) or in the shade (H) were harvested and stored for 13 days at 20 °C. An evaluation of fruit soluble solids, acidity, color, starch degradation, firmness, cell wall yield, pectin and matrix glycan solubilization, depolymerization, and monosaccharide composition was carried out. Sun-exposed pears showed more advanced color development and similar levels of starch degradation, sugars, and acids than shaded fruit. Sunlight-grown pears were at harvest firmer than shade-grown pears. Both fruit groups softened during storage at 20 °C, but even after ripening, sun-exposed pears remained firmer. Sunlight exposure did not have a great impact on pectin molecular weight. Instead, at harvest a higher proportion of water-solubilized uronic acids and alkali-solubilized neutral sugars and a larger mean molecular size of tightly bound glycans was found in sun-exposed pears. During ripening cell wall catabolism took place in both sun- and shade-grown pears, but pectin solubilization was clearly delayed in sun-exposed fruit. This was associated with decreased removal of RG I-arabinan side chains rather than with reduced depolymerization.     

Quantitative mass spectrometry identifies insulin signaling targets in C. elegans

DAF-2, an insulin receptor-like protein, regulates metabolism, development, and aging in Caenorhabditis elegans. In a quantitative proteomic study, we identified 86 proteins that were more or less abundant in long-lived daf-2 mutant worms than in wild-type worms. Genetic studies on a subset of these proteins indicated that they act in one or more processes regulated by DAF-2, including entry into the dauer developmental stage and aging. In particular, we discovered a compensatory mechanism activated in response to reduced DAF-2 signaling, which involves the protein phosphatase calcineurin.     

Inversions and gene order shuffling in Anopheles gambiae and A. funestus

In tropical Africa, Anopheles funestus is one of the three most important malaria vectors. We physically mapped 157 A. funestus complementary DNAs (cDNAs) to the polytene chromosomes of this species. Sequences of the cDNAs were mapped in silico to the A. gambiae genome as part of a comparative genomic study of synteny, gene order, and sequence conservation between A. funestus and A. gambiae. These species are in the same subgenus and diverged about as recently as humans and chimpanzees. Despite nearly perfect preservation of synteny, we found substantial shuffling of gene order along corresponding chromosome arms. Since the divergence of these species, at least 70 chromosomal inversions have been fixed, the highest rate of rearrangement of any eukaryote studied to date. The high incidence of paracentric inversions and limited colinearity suggests that locating genes in one anopheline species based on gene order in another may be limited to closely related taxa.     

Soil organic matter and sorption capacity under different soil management practices in a productive vineyard

The effect of soil organic matter (SOM) on sorptive parameters under different soil management practices in Rendzic Leptosol was studied. In 2006, an experiment of different management practices in a productive vineyard was established in the locality of Nitra-Dra?ovce (Slovakia). The following treatments were established: (1) control (grass without fertilization), (2) T (tillage), (3) T + FYM (tillage + farmyard manure), (4) G + NPK3 (grass + 3rd intensity of fertilization for vineyards), (5) G + NPK1 (grass + 1st intensity of fertilization for vineyards). Soil samples were collected every month during the year 2010. Obtained results showed increased hydrolytic acidity (by 23%), sum of basic cations (by 37%) and decreased total cation exchange capacity (CEC) (by 36%) with higher doses of fertilization in comparison to control. Application of farmyard manure had a positive effect on the increase in the SOM cation sorption capacity. Positive correlations between pH and sum of basic cations (SBC) (r = 0.493, p ≤ 0.001), CEC (r = 0.498, p ≤ 0.001) and cation sorption capacity of SOM (r = 0.391, p ≤ 0.01) were observed. Higher values of labile carbon:potentially mineralizable nitrogen (C_L:N_pot) ratio corresponded with lesser CEC, SBC and base saturation values in the soil. With increased humus quality (higher values of humic acid:fulvic acid (C_HA:C_FA) ratio), cation sorption capacity of SOM significantly increased (r = 0.329, p ≤ 0.01). The results of this study proved that the application of farmyard manure had a positive effect on the increase of SOM sorption capacity, but higher doses of mineral fertilizers added to soil had a negative effect.