Acute Heat Stress and Reduced Nutrient Intake Alter Intestinal Proteomic Profile and Gene Expression in Pigs

Heat stress and reduced feed intake negatively affect intestinal integrity and barrier function. Our objective was to compare ileum protein profiles of pigs subjected to 12 hours of HS, thermal neutral ad libitum feed intake, or pair-fed to heat stress feed intake under thermal neutral conditions (pair-fed thermal neutral). 2D-Differential In Gel Electrophoresis and gene expression were performed. Relative abundance of 281 and 138 spots differed due to heat stress, compared to thermal neutral and pair-fed thermal neutral pigs, respectively. However, only 20 proteins were different due to feed intake (thermal neutral versus pair-fed thermal neutral). Heat stress increased mRNA expression of heat shock proteins and protein abundance of heat shock proteins 27, 70, 90-α and β were also increased. Heat stress reduced ileum abundance of several metabolic enzymes, many of which are involved in the glycolytic or TCA pathways, indicating a change in metabolic priorities. Stress response enzymes peroxiredoxin-1 and peptidyl-prolyl cis-trans isomerase A were decreased in pair-fed thermal neutral and thermal neutral pigs compared to heat stress. Heat stress increased mRNA abundance markers of ileum hypoxia. Altogether, these data show that heat stress directly alters intestinal protein and mRNA profiles largely independent of reduced feed intake. These changes may be related to the reduced intestinal integrity associated with heat stress.     

Endometrial expression of selected transcripts involved in prostaglandin synthesis in cows with endometritis

Several cytokines and prostaglandins play an important role in preparing the endometrium for implantation and mediating pro-inflammatory events. The aim of the present study was to examine mRNA expression of interleukin 1α (IL-1α), interleukin receptor antagonist (IL-1-RN), cytosolic prostaglandin E synthase (cPGES), microsomal PGES (mPGES-1 and mPGES-2) and lipocalin-type PGDS (L-PGDS) in the bovine endometrium. Endometrial epithelium samples were collected ex vivo from cows with different status of health at day 21-27 postpartum on a dairy farm. Three groups (n = 9 animals each) were defined: (1) healthy cows with no signs of endometritis (control group), (2) cows with subclinical endometritis, and (3) cows with signs of clinical endometritis. Oestrous cycle-dependent mRNA expression pattern was investigated using bovine endometrial epithelial cells from healthy uteri collected at the abattoir. These uteri were classified into post-ovulatory, early-to-mid luteal, late luteal or pre-ovulatory phase (n = 8 animals for each cycle phase). After collecting endometrial epithelium using the cytobrush-method, mRNA analysis was performed by real-time RT-PCR. L-PGDS, IL-1α and IL-1-RN mRNA were expressed significantly higher (P < 0.05) in the endometrium of cows with subclinical or clinical endometritis compared with healthy cows. A twofold lower cPGES mRNA expression (P < 0.05) was detected in cows with subclinical endometritis compared to healthy cows. L-PGDS and IL-1-RN mRNA expression was increased (P < 0.05) after ovulation compared with the pre-ovulatory or luteal phase, respectively. These results support the hypothesis that a dys-regulated cytokine and/or prostaglandin profile in the uterus could be induced by subclinical endometritis or clinical endometritis.     

Infection with virulent and avirulent P. syringae strains differentially affects photosynthesis and sink metabolism in Arabidopsis leaves

Infection of plants with pathogens leads not only to the induction of defence reactions but also to changes in carbohydrate metabolism. In this study, the effects of infection by a virulent and an avirulent strain of P. syringae on spatio-temporal changes in photosynthesis were compared using chlorophyll fluorescence imaging. The maximum PSII quantum yield, effective PSII quantum yield and nonphotochemical quenching were decreased in Arabidopsis leaves infected with either strain. At the same time, the quantum yield of nonregulated energy dissipation was increased. These changes could be detected by chlorophyll fluorescence imaging before symptoms were visible by eye. The effects were restricted to the vicinity of the infection site and did not spread to uninfected areas of the leaf. Qualitatively similar changes in photosynthetic parameters were observed in both interactions. Major differences between the responses to both strains were evident in the onset and time course of changes. A decrease in photosynthesis was detectable already at 3 h only after challenge with the avirulent strain while after 48 h the rate of photosynthesis was lower with the virulent strain. In contrast to photosynthesis, the regulation of marker genes for source/sink relations and the activities of invertase isoenzymes showed qualitative differences between both interactions. Inoculation of the virulent but not the avirulent strain resulted in downregulation of photosynthetic genes and upregulation of vacuolar invertases. The activity of vacuolar invertases transiently increased upon infection with the virulent strain but decreased with the avirulent strain while extracellular invertase activity was downregulated in both interactions.     

Umbel Browning and Stem Necrosis: a New Disease of Fennel in Bulgaria

A new fungal disease on fennel has been observed with increasing frequency in Bulgaria. The main symptoms were expressed as umbel browning and stem necrosis. Umbels could be destroyed completely and produced no fruits. Stem necrosis observed in the second and subsequent years of cultivation caused death of many twigs or whole plants. Pycnidia containing alpha and beta conidia developed on diseased umbels, twigs and stems. Perithecia with mature ascospores were found in vivo on the overwintered plant parts, and in vitro mainly on malt yeast extract agar and oatmeal agar. Diaporthe angelicae (anamorph Phomopsis foeniculi) was established as the causal agent. Isolates showed great variability in colony colour, linear growth, quantity of pycnidia and ability to produce teleomorph in vitro. Isolates obtained from fennel were able to infect other species belonging to the Apiaceae family, making the disease a potential threat for them, too.     

Food consumption and growth of Atlantic salmon Salmo salar parr in sub-Arctic rivers: empirical support for food limitation and competition

The quantitative food consumption and somatic growth of Atlantic salmon Salmo salar parr were compared between three sub-Arctic rivers in northern Norway and Finland, addressing the potential occurrence of resource limitation and interspecific competition. In one of the rivers, previous resource partitioning studies have suggested severe dietary competition between juvenile S. salar and a dense population of alpine bullheads Cottus poecilopus . It was hypothesized that S. salar parr in this river would have restricted food consumption and growth rates compared to the S. salar populations in the other two rivers where interspecific competition was less likely to occur. The feeding and growth performance differed significantly between the S. salar populations. The lowest food acquisition and growth rates were in the S. salar parr population living in sympatry with C. poecilopus , confirming a restricted food supply for the S. salar parr and providing empirical support for the presence of resource limitation and interspecific food competition in this river system. The study reveals that S. salar parr in sub-Arctic rivers may experience food limitations resulting in diminished growth rates.     

Prey diversity as a driver of resource partitioning between river‐dwelling fish species

Although food resource partitioning among sympatric species has often been explored in riverine systems, the potential influence of prey diversity on resource partitioning is little known. Using empirical data, we modeled food resource partitioning (assessed as dietary overlap) of coexisting juvenile Atlantic salmon (Salmo salar) and alpine bullhead (Cottus poecilopus). Explanatory variables incorporated into the model were fish abundance, benthic prey diversity and abundance, and several dietary metrics to give a total of seventeen potential explanatory variables. First, a forward stepwise procedure based on the Akaike information criterion was used to select explanatory variables with significant effects on food resource partitioning. Then, linear mixed‐effect models were constructed using the selected explanatory variables and with sampling site as a random factor. Food resource partitioning between salmon and bullhead increased significantly with increasing prey diversity, and the variation in food resource partitioning was best described by the model that included prey diversity as the only explanatory variable. This study provides empirical support for the notion that prey diversity is a key driver of resource partitioning among competing species.     

Fast and accurate determination of sites along the FUT2 in vitro transcript that are accessible to antisense oligonucleotides by application of secondary structure predictions and RNase H in combination with MALDI-TOF mass spectrometry

Alteration of gene expression by use of antisense oligonucleotides has considerable potential for therapeutic purposes and scientific studies. Although applied for almost 25 years, this technique is still associated with difficulties in finding antisense-effective regions along the target mRNA. This is mainly due to strong secondary structures preventing binding of antisense oligonucleotides and RNase H, playing a major role in antisense-mediated degradation of the mRNA. These difficulties make empirical testing of a large number of sequences complementary to various sites in the target mRNA a very lengthy and troublesome procedure. To overcome this problem, more recent strategies to find efficient antisense sites are based on secondary structure prediction and RNase H-dependent mechanisms. We were the first who directly combined these two strategies; antisense oligonucleotides complementary to predicted unpaired target mRNA regions were designed and hybridized to the corresponding RNAs. Incubation with RNase H led to cleavage of the RNA at the respective hybridization sites. Analysis of the RNA fragments by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, which has not been used in this context before, allowed exact determination of the cleavage site. Thus the technique described here is very promising when searching for effective antisense sites.