Regression tree analysis of the relationship between the concentrations of antimicrobial components and the microbiota of normal milk from dairy cows

The purpose of this study was to determine the concentrations of antimicrobial components (immunoglobulin A (IgA), lactoferrin (LF), lingual antimicrobial peptide (LAP), and S100A7) in normal milk and their relation to host factors (Age, somatic cell count (SCC), days in milk, richness, and alpha diversity of the milk microbiota) in dairy cows using multivariate regression tree analyses, and to clarify how the milk microbiota is related to the obtained results. Thirty normal milk samples were collected from a commercial dairy farm in June 2020. The thresholds that predicted the concentration of each antimicrobial component in milk were obtained by regression tree analysis, and the beta-diversity of the milk microbiota composition between groups divided according to each threshold was compared by an analysis of similarities test. The IgA and LF concentrations were mainly predicted by the SCC (177,500 and 70,000 cells/ml, respectively), and the LAP and S100A7 concentrations were predicted by Age (29.667 and 40.3 months, respectively). No relationship was observed between the concentration of IgA, LAP, or S100A7 and the milk microbiota composition between the groups divided by the threshold for prediction, but the milk microbiota composition was significantly different between the groups divided by the threshold for predicting the LF concentration. Our results indicated that the LF concentration in normal milk may be associated with the milk microbiota composition.     

Conduciveness of different soilless growing media to <Emphasis Type="Italic">Pythium</Emphasis> root and crown rot of cucumber under near-commercial conditions

Substrates made from rockwool, coir dust, pumice and perlite were compared for conduciveness to Pythium root and crown rot in cucumber under near-commercial conditions. Rockwool slabs of 7 cm height were more conducive to the Pythium disease than coir dust slabs, pumice or perlite under these conditions. Temperature, oxygen concentration and water content were determined in the substrates to explain differences in conduciveness between the inorganic substrates rockwool, pumice and perlite by differences in the physical conditions. Temperature and oxygen concentration could not explain the differences but the higher disease level on rockwool was associated with a much higher water content of this substrate as compared to coir dust, pumice and perlite. Increasing the height of the substrate from 7 to 14 cm greatly decreased the percentage of diseased plants due to the Pythium disease on rockwool but had no effect on the level of disease on perlite when the substrate had been infested 4 cm below the planting hole. This difference in response in substrate height between rockwool and perlite could be explained by a much larger decrease in water content with substrate height in the rockwool than in the perlite substrate. Temperature in the substrates were above 30 °C for more than 6 h on sunny days in June and reached maximum values of 35 °C or more. These temperatures are highly favourable for the pathogen P. aphanidermatum but will have adverse effects on most biocontrol strains.     

Pathogenesis of reproductive failure induced by Trypanosoma vivax in experimentally infected pregnant ewes

The present study was aimed at investigating the effect of experimental infection by Trypanosoma vivax in different stages of pregnancy, determining the pathogenesis of reproductive failure, and confirming transplacental transmission. We used 12 pregnant ewes distributed into four experimental groups: G1, was formed by three ewes infected with T. vivax in the first third of pregnancy (30 days); G2 comprised three infected ewes in the final third of pregnancy (100 days); G3 and G4 were composed of three non-infected ewes with the same gestational period, respectively. Each ewe of G1 and G2 was inoculated with 1.25 × 10⁵ tripomastigotes. Clinical examination, determination of parasitemia, serum biochemistry (albumin, total protein, glucose, cholesterol, and urea), packed cell volume (PCV), serum progesterone, and pathological examination were performed. Placenta, amniotic fluid, blood and tissues from the fetuses and stillbirths were submitted to PCR. Two ewes of G1 (Ewe 1 and 3) presented severe infection and died in the 34^th and 35^th days post-infection (dpi), respectively; but both fetuses were recovered during necropsy. In G2, Ewe 5 aborted two fetuses on the 130^th day (30 dpi) of pregnancy; and Ewe 6 aborted one fetus in the 140^th day (40 dpi) of gestation. Ewes 2 and 4 delivered two weak lambs that died five days after birth. Factors possibly involved with the reproductive failure included high parasitemia, fever, low PCV, body score, serum glucose, total protein, cholesterol, and progesterone. Hepatitis, pericarditis, and encephalitis were observed in the aborted fetuses. The presence of T. vivax DNA in the placenta, amniotic fluid, blood, and tissues from the fetuses confirms the transplacental transmission of the parasite. Histological lesion in the fetuses and placenta also suggest the involvement of the parasite in the etiopathogenesis of reproductive failure in ewes.     

An outbreak of Newcastle disease in free-living pheasants (Phasianus colchicus).

The epidemiology of an outbreak of Newcastle disease in a population of approximately 12,000 free-living pheasants (Phasianus colchicus) on the island of Faen? in Denmark in 1996 is described. The mortality during the epizootic was 56%. The spread of the disease between 7 groups of pheasants could be demonstrated over an observation period of 3 weeks. A total of 70 avian paramyxovirus serotype 1 (APMV-1) isolates was made from the flock. The intra cerebral pathogenicity indices of the 4 isolates tested were in the range 1.78-1.88. By means of immunoperoxidase monolayer assay with murine monoclonal antibodies and sequence analysis of an RT-PCR amplified segment of the F0 viral protein it was found, that the virus belonged to the highly virulent C1 antigenic group and that the amino acid sequence at the F0 cleavage site corresponded with the sequences of virulent APMV-1 strains. Based on the epidemiological circumstances it is believed that the virus was transmitted to the pheasants by feral birds.     

Cloning of two Atlantic salmon growth hormone receptor isoforms and <Emphasis Type="Italic">in vitro</Emphasis> ligand-binding response

Two isoforms of the full-length cDNA of the growth hormone receptor (GHR) of the Atlantic salmon (Salmo salar; ss) were cloned by a PCR approach using RACE. Respectively, the cDNA sequences of ssGHR isoforms 1 and 2 are 2654 and 2608 nucleotides long, with 1782 and 1773 nucleotide ORFs. The resulting coded proteins are 594 and 590 aa long, with 19 and 20 aa signal peptides. The two isoforms share 86% protein and 87% cDNA sequence similarity. Isoform 1 is most similar to other salmonid GHR isoforms 1 while isoform 2 is most similar to salmonid GHR isoforms 2 (93–95%). Similarity with other teleost species was lower (37–44%). The bioactivity of the cloned ssGHR was tested by transfecting the ssGHR isoform 1 cDNA into CHO-K1 hamster cells, incubating with recombinant salmon GH (sGH) or native ovine prolactin (oPRL), and measuring cell proliferation by the MTT assay. The ssGHR-transfected cells significantly increased proliferation when stimulated by sGH at all concentrations. oPRL stimulated ssGHR-transfected cells at higher concentrations due to receptor cross reaction. ssGHR isoforms 1 and 2 contain a single transmembrane domain and the typical conserved motifs found in other teleost GHRs, including four paired cysteine residues and five potential N-glycosylation sites in the extracellular domain, Box I and Box II, as well as seven potential tyrosine phosphorylation sites in the intracellular domain. However, in salmonids, these motifs differ from those of other teleosts, and could be responsible for differentiated hormone binding, signal transduction and response.     

Low-Molecular-Weight Fucoidan Induces Endothelial Cell Migration via the PI3K/AKT Pathway and Modulates the Transcription of Genes Involved in Angiogenesis

Low-molecular-weight fucoidan (LMWF) is a sulfated polysaccharide extracted from brown seaweed that presents antithrombotic and pro-angiogenic properties. However, its mechanism of action is not well-characterized. Here, we studied the effects of LMWF on cell signaling and whole genome expression in human umbilical vein endothelial cells and endothelial colony forming cells. We observed that LMWF and vascular endothelial growth factor had synergistic effects on cell signaling, and more interestingly that LMWF by itself, in the absence of other growth factors, was able to trigger the activation of the PI3K/AKT pathway, which plays a crucial role in angiogenesis and vasculogenesis. We also observed that the effects of LMWF on cell migration were PI3K/AKT-dependent and that LMWF modulated the expression of genes involved at different levels of the neovessel formation process, such as cell migration and cytoskeleton organization, cell mobilization and homing. This provides a better understanding of LMWF’s mechanism of action and confirms that it could be an interesting therapeutic approach for vascular repair.     

Chemical structure and thermal properties of lignin modified with polyethylene glycol during steam explosion

Thermoplastic processing of lignin is restricted by its high glass transition temperature (T _g). In this study, lignin was modified with polyethylene glycol (PEG) during steam explosion to improve its thermoplastic properties, and the effects of steam explosion and PEG on the chemical structure and thermal properties of lignin were investigated. Structure characterization using Fourier transform infrared spectroscopy showed that hydroxyl and ether functional groups increased and the activity of lignin was improved by steam explosion. In addition, steam explosion treatment was more effective than heat treatment for promoting the reaction of PEG with lignin. Solid-state ¹³C NMR revealed that PEG was grafted onto lignin. The T _g of raw lignin was 164.1 °C; after steam explosion, lignin exhibited more than one T _gs. The T _g of lignin was reduced when the steam explosion temperature increased and decreased further, to around 60 °C, when PEG was used to modify lignin. Therefore, this work provides an effective approach to reducing the high T _g of lignin.