The northern corn leaf blight resistance gene Ht1 encodes an nucleotide-binding,leucine-rich repeat immune receptor

Northern corn leaf blight, caused by the fungal pathogen Exserohilum turcicum, is a major disease of maize. The first major locus conferring resistance to E. turcicum race 0, Ht1, was identified over 50 years ago, but the underlying gene has remained unknown. We employed a map-based cloning strategy to identify the Ht1 causal gene, which was found to be a coiled-coil nucleotide-binding, leucine-rich repeat (NLR) gene, which we named PH4GP-Ht1. Transgenic testing confirmed that introducing the native PH4GP-Ht1 sequence to a susceptible maize variety resulted in resistance to E. turcicum race 0. A survey of the maize nested association mapping genomes revealed that susceptible Ht1 alleles had very low to no expression of the gene. Overexpression of the susceptible B73 allele, however, did not result in resistant plants, indicating that sequence variations may underlie the difference between resistant and susceptible phenotypes. Modelling of the PH4GP-Ht1 protein indicated that it has structural homology to the Arabidopsis NLR resistance gene ZAR1, and probably forms a similar homopentamer structure following activation. RNA sequencing data from an infection time course revealed that 1 week after inoculation there was a threefold reduction in fungal biomass in the PH4GP-Ht1 transgenic plants compared to wild-type plants. Furthermore, PH4GP-Ht1 transgenics had significantly more inoculation-responsive differentially expressed genes than wild-type plants, with enrichment seen in genes associated with both defence and photosynthesis. These results demonstrate that the NLR PH4GP-Ht1 is the causal gene underlying Ht1, which represents a different mode of action compared to the previously reported wall-associated kinase northern corn leaf blight resistance gene Htn1/Ht2/Ht3.     

A study of prostaglandin F2α as the luteolysin in swine: III effects of estradiol valerate on prostaglandin F, progestins, estrone and estradiol concentrations in the utero-ovarian vein of nonpregnant gilts

Polyvinyl catheters were placed into the right and left utero-ovarian veins and saphenous vein and artery of three control (C) and four estradiol valerate (EV) treated gilts on Day 9 after onset of estrus. The EV treated gilts received 5mg EV/day on Days 11 through 15 after onset of estrus. On Days 12 through 17 utero-ovarian vein blood samples were collected at 15 min intervals from 0700 to 1000 hr and 1900 to 2200 hr and single samples were taken at 1100 and 2300 hr. Peripheral blood samples (saphenous vein or artery) were taken at 0700, 1100, 1900 and 2300 hr from Day 12 until the control gilts returned to estrus or until Day 25 for EV treated gilts and used to measure plasma steroid hormone concentrations. Utero-ovarian vein prostaglandin F (PGF) concentrations (ng/ml, n=1,177) were measured by RIA. Status (control EV treated gilts) by day interactions were detected (P=.10). Curvilinear day trends were detected for plasma PGF concentrations in control (P<.01) but not EV treated gilts. PGF concentrations ( ) for control and EV treated gilts were 1.20 ± 2.08 and .26 ± .84 ng/ml, respectively. PGF peaks (concentrations greater than + 2 S.D.) occured with greater frequency in control gilts (X² = 4.87; P<.05). The interestrus interval ( ) for control and treated gilts was 19.0 ± .6 and 146.5 ± 74.8 days, respectively. Data indicate that estradiol valerate may exert its luteotrophic effect by preventing PGF release from the uterus.     

Quantitating and engineering the ion specificity of an EF-hand-like Ca2+ binding.

The Escherichia coli D-galactose and D-glucose receptor, an aqueous periplasmic receptor that triggers sugar sensing and transport, possesses a single Ca2+ binding site similar in structure and specificity to the EF-hand class of sites found in eukaryotic Ca2+ signaling proteins including calmodulin and its homologues. A universal feature of these sites is the use of a pentagonal bipyramidal array of seven oxygens to coordinate bound Ca2+. Here we investigate the mechanisms used by this coordinating array to control ion specificity. To vary the cavity size and charge of the array, we have replaced axial glutamine 142 in the prokaryotic site with asparagine, glutamate, and aspartate. The ion selectivities of the resulting engineered sites have been quantitated by measuring dissociation constants for a series of spherical metal ions, differing in increments of radius and charge, from groups Ia, IIa, and IIIa and the lanthanides. Dramatic specificity changes are observed: sites containing an engineered smaller side chain (Asn or Asp) bind the largest cations up to 50-fold more tightly than the native site; and sites containing an engineered negative side chain (Glu or Asp) exhibit preferences for trivalent over divalent cations up to 1900-fold higher than the native site. The results indicate that the cavity size and negative charge of the coordination array play key roles in selective Ca2+ binding and that the array can be engineered to preferentially bind other cations.     

Androstenedione, dehydroepiandrosterone and testosterone in ovarian vein plasma and androstenedione in peripheral arterial plasma during the bovine oestrous cycle

Catheters were placed in the carotid artery via a facial artery (n = 12) and in the ovarian vein (n = 12), and, in conjunction, electromagnetic flow meters were placed around the ovarian artery (n = 6) in cyclic beef cows. Androstenedione was quantitatively the highest and dehydroepiandrosterone the lowest of the ovarian androgens measured. Ovarian androgens were correlated positively with each other (P less than 0.05) but not with ovarian blood flow or day of the cycle. There was a trend for spikes of androgen release (ovarian vein concentration x ovarian blood flow) from the ovary to be greatest during the period of decreasing progesterone and CL regression. However, only with testosterone were spikes of release different (Days--13 to--9 less than Days -8 to -4; P less than 0.05; Day 0 = oestrus). The dynamic changes in ovarian androgens noted in this study were compatible with the concept of continuous follicular development and atresia throughout the oestrous cycle.     

Evaluation of GABA Production and Probiotic Activities of Enterococcus faecium BS5

Probiotics and Antimicrobial Proteins - Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of...     

An NO Donor Approach to Neuroprotective and Procognitive Estrogen Therapy Overcomes Loss of NO Synthase Function and Potentially Thrombotic Risk

Selective estrogen receptor modulators (SERMs) are effective therapeutics that preserve favorable actions of estrogens on bone and act as antiestrogens in breast tissue, decreasing the risk of vertebral fractures and breast cancer, but their potential in neuroprotective and procognitive therapy is limited by: 1) an increased lifetime risk of thrombotic events; and 2) an attenuated response to estrogens with age, sometimes linked to endothelial nitric oxide synthase (eNOS) dysfunction. Herein, three 3^rd generation SERMs with similar high affinity for estrogen receptors (ERα, ERβ) were studied: desmethylarzoxifene (DMA), FDMA, and a novel NO-donating SERM (NO-DMA). Neuroprotection was studied in primary rat neurons exposed to oxygen glucose deprivation; reversal of cholinergic cognitive deficit was studied in mice in a behavioral model of memory; long term potentiation (LTP), underlying cognition, was measured in hippocampal slices from older 3×Tg Alzheimer''s transgenic mice; vasodilation was measured in rat aortic strips; and anticoagulant activity was compared. Pharmacologic blockade of GPR30 and NOS; denudation of endothelium; measurement of NO; and genetic knockout of eNOS were used to probe mechanism. Comparison of the three chemical probes indicates key roles for GPR30 and eNOS in mediating therapeutic activity. Procognitive, vasodilator and anticoagulant activities of DMA were found to be eNOS dependent, while neuroprotection and restoration of LTP were both shown to be dependent upon GPR30, a G-protein coupled receptor mediating estrogenic function. Finally, the observation that an NO-SERM shows enhanced vasodilation and anticoagulant activity, while retaining the positive attributes of SERMs even in the presence of NOS dysfunction, indicates a potential therapeutic approach without the increased risk of thrombotic events.     

A Novel Anti-Inflammatory and Pro-Resolving Role for Resolvin D1 in Acute Cigarette Smoke-Induced Lung Inflammation

Introduction

Cigarette smoke is a profound pro-inflammatory stimulus that contributes to acute lung injuries and to chronic lung disease including COPD (emphysema and chronic bronchitis). Until recently, it was assumed that resolution of inflammation was a passive process that occurred once the inflammatory stimulus was removed. It is now recognized that resolution of inflammation is a bioactive process, mediated by specialized lipid mediators, and that normal homeostasis is maintained by a balance between pro-inflammatory and pro-resolving pathways. These novel small lipid mediators, including the resolvins, protectins and maresins, are bioactive products mainly derived from dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFA). We hypothesize that resolvin D1 (RvD1) has potent anti-inflammatory and pro-resolving effects in a model of cigarette smoke-induced lung inflammation.

Methods

Primary human lung fibroblasts, small airway epithelial cells and blood monocytes were treated with IL-1β or cigarette smoke extract in combination with RvD1 in vitro, production of pro-inflammatory mediators was measured. Mice were exposed to dilute mainstream cigarette smoke and treated with RvD1 either concurrently with smoke or after smoking cessation. The effects on lung inflammation and lung macrophage populations were assessed.

Results

RvD1 suppressed production of pro-inflammatory mediators by primary human cells in a dose-dependent manner. Treatment of mice with RvD1 concurrently with cigarette smoke exposure significantly reduced neutrophilic lung inflammation and production of pro-inflammatory cytokines, while upregulating the anti-inflammatory cytokine IL-10. RvD1 promoted differentiation of alternatively activated (M2) macrophages and neutrophil efferocytosis. RvD1 also accelerated the resolution of lung inflammation when given after the final smoke exposure.

Conclusions

RvD1 has potent anti-inflammatory and pro-resolving effects in cells and mice exposed to cigarette smoke. Resolvins have strong potential as a novel therapeutic approach to resolve lung injury caused by smoke and pulmonary toxicants.