Distinct impact of arbuscular mycorrhizal isolates on tomato plant tolerance to drought combined with chronic and acute heat stress.

Arbuscular mycorrhizal (AM) fungi could mitigate individual drought and heat stress in host plants. However, there are still major gaps in our understanding of AM symbiosis response to the combined stresses. Here, we compared seven AM fungi, Rhizophagus irregularis, Funneliformis mosseae, Funneliformis geosporum, Funneliformis verruculosum, Funneliformis coronatum, Septoglomus deserticola, Septoglomus constrictum, distributed to many world regions in terms of their impacts on tomato endurance to combined drought and chronic heat as well as combined drought and heat shock. A multidisciplinary approach including morphometric, ecophysiological, biochemical, targeted metabolic (by ultrahigh-performance LC-MS), and molecular analyses was applied. The variation among AM fungi isolates in the enhancement in leaf water potential, stomatal conductance, photosynthetic activity, and maximal PSII photochemical efficiency, proline accumulation, antioxidant enzymes (POD, SOD, CAT), and lowered ROS markers (H2O2, MDA) in host plants under combined stresses were observed. S. constrictum inoculation could better enhanced the host plant physiology and biochemical parameters, while F. geosporum colonization less positively influenced the host plants than other treatments under both combined stresses. F. mosseae- and S. constrictum-associated plants showed the common AM-induced modifications and AM species-specific alterations in phytohormones (ABA, SA, JA, IAA), aquaporin (SlSIP1-2; SlTIP2-3; SlNIP2-1; SlPIP2-1) and abiotic stress-responsive genes (SlAREB1, SlLEA, SlHSP70, SlHSP90) in host plants under combined stresses. Altogether, mycorrhizal mitigation of the negative impacts of drought + prolonged heat and drought + acute heat, with the variation among different AM fungi isolates, depending on the specific combined stress and stress duration.

Alternative to ZnO to establish balanced intestinal microbiota for weaning piglets.

A wide range of phytobiotic feed additives are available on the market claiming to have beneficial effects on the growth of the host animal and to promote the development of a balanced microflora. The present study investigated the effects of the phytobiotic-prebiotic mixture of curcumin, wheat germ, and chicory on the growth performance and on the intestinal microflora composition of weaning piglets. Post weaning diarrhea causes significant losses for the producers, most commonly it is prevented by feeding high doses of zinc oxide (ZnO). The effect of a phytobiotic-prebiotic feed additive (1 kg T-1) was compared to a positive control (3.1 kg T-1 ZnO) and to a negative control (no feed supplement) in an in vivo animal trial. There was no significant difference in the final body weight and average daily gain of the trial and positive control groups, and both groups showed significantly (P<0.05) better results than the negative control. The feed conversion ratio of the phytobiotic-prebiotic supplemented group was significantly improved (P<0.05) compared to both controls. Both phytobiotic-prebiotic mixture and ZnO were able to significantly reduce (P<0.05) the amount of coliforms after weaning, even though ZnO reduced the amount of coliforms more efficiently than the trial feed additive, it also reduced the amount of potentially beneficial bacteria. Metagenomic data also corroborated the above conclusion. In the trial and positive control groups, the relative abundance of Enterobacteriaceae decreased by 85 and 88% between 3 weeks and 6 weeks of age, while in the negative control group a slight increase occurred. Lactobacillaceae were more abundant in the trial group (29.98%) than in the positive (8.67%) or in the negative (22.45%) control groups at 6 weeks of age. In summary, this study demonstrated that a phytobiotic-prebiotic feed additive may be a real alternative to ZnO for the prevention of post weaning diarrhea and promote the development of a balanced gut system.

How arbuscular mycorrhizal fungi influence the defense system of sunflower during different abiotic stresses.

The association between terrestrial plants and arbuscular mycorrhizal (AM) fungi is one of the most common and widespread mutualistic plant-fungi interaction. AM fungi are of beneficial effects on the water and nutrient uptake of plants and increase plant defense mechanisms to alleviate different stresses. The aim of this study was to determine the level of polyphenol oxidase (PPO), guaiacol peroxidase (POX) and glutathione S-transferase (GST) enzyme activities and to track the expression of glutathione S-transferase (GST) gene in plant-arbuscular mycorrhizal system under temperature- and mechanical stress conditions. Our results suggest that induced tolerance of mycorrhizal sunflower to high temperature may be attributed to the induction of GST, POX and PPO enzyme activities as well as to the elevated expression of GST. However, the degree of tolerance of the plant is significantly influenced by the age which is probably justified by the energy considerations.

CDX2 protein expression compared to alcian blue staining in the evaluation of esophageal intestinal metaplasia.

AIM: To compare the sensitivity and specificity of CDX2 and alcian blue (AB) pH 2.5 staining in identifying esophageal intestinal metaplasia. METHODS: One hundred and ninty-nine biopsies from 186 patients were retrospectively reviewed and categorized as Barrett's esophagus (BE) (n = 108); non-Barrett's esophagus (NBE) (n = 48); columnar blue cells (CB) and esophageal glands (EG) (n = 43). The biopsies were stained with AB and immunostained for CDX2 using a mouse monoclonal antibody from Biogenex (clone CDX2-88) and the Ventana Discovery X automated immunostainer. The positive and negative predictive value of each group was used to determine the predictive power of CDX2 and AB in diagnosing intestinal metaplasia. RESULTS: All of the 108 BE biopsies (100%) were positive for AB and 102 of them (94.4%) were positive for CDX2. The six BE patients (5.6%) who failed to stain with CDX2 were found to have lost the focus of intestinal metaplasia upon deeper sectioning for immunostaining. Both AB and CDX2 were negative in 43 out of 48 (89.6%) NBE cases. Five NBE patients (10.4%) were falsely positive for AB due to the presence of EG and CB in these biopsies. These cases were all CDX2 negative. In addition, 5 AB negative NBE were found to be CDX2 positive. Based on these results the CDX2 immunostain had similar sensitivity but higher specificity (100% vs about 91%) than AB in detecting intestinal type metaplasia in these samples. Our data shows that CDX2 has a better PPV in detecting intestinal metaplasia as compared to AB (95.6% vs 71.5%, respectively). CONCLUSION: CDX2 has a better positive predictive value than AB in detecting intestinal metaplasia. CDX2 may be useful when challenged by gastro-esophageal biopsies containing mimikers of BE.

Quantification of subfamily I.2.C catechol 2,3-dioxygenase mRNA transcripts in groundwater samples of an oxygen-limited BTEX-contaminated site.

Low dissolved oxygen concentration of subsurface environments is a limiting factor for microbial aromatic hydrocarbon degradation, and to date, there are only a limited number of available reports on functional genes and microbes that take part in the degradation of aromatic hydrocarbons under hypoxic conditions. Recent discoveries shed light on the prevalence of subfamily I.2.C catechol 2,3-dioxygenases in petroleum hydrocarbon contaminated hypoxic groundwaters, and their considerable environmental importance was suggested. Here, we report on a Hungarian aromatic hydrocarbon (methyl-substituted benzene derivatives, mostly xylenes) contaminated site where we investigated this presumption. Groundwater samples were taken from the center and the edge of the contaminant plume and beyond the plume. mRNA transcripts of subfamily I.2.C catechol 2,3-dioxygenases were detected in considerable amounts in the contaminated samples by qPCR analysis, while activity of subfamily I.2.A, which includes the largest group of extradiol dioxygenases described by culture-dependent studies and thought to be widely distributed in BTEX-contaminated environments, was not observed. Bacterial community structure analyses showed the predominance of genus Rhodoferax related species in the contaminated samples.