Iron metabolism

Extract

The introduction of chemical restraint into horse practice brought significant advantages in handling fearful and fractious animals as well as allowing the practitioner to carry out procedures which would normally arouse considerable resistance from the equine patient. Phenothiazine derivatives were widely used for these purposes prior to the introduction of xylazine hydrochloride, a drug which was synthesised in Germany in 1962 by Bayer, A. G., Leverkusen, tested underthe code name Bayer Va 1470 and marketed under the trade name Rompun. In view of the increasing use of xylazine in equine practice it seems worth-while to review the literature on the pharmacological action and clinical use of this agent in horses.     

Structural Changes of Starch Molecules in Barley Grains During Germination

The germination of barley grains is an important step in malt production for beer brewing. This study examines the changes in starch molecular structure in barley grains under optimal conditions for sprouting. Two barley varieties were tested: Schooner and Grimmett, which are low and moderate dormancy grains, with >90 and <5% of grains germinating within two days in sprouting conditions, respectively. The barley grains were germinated in humid conditions after being soaked in excess water for 24 h. The grain weight and starch content of Schooner decreased significantly (P < 0.05) with germination time, whereas those of Grimmett showed no significant changes (P > 0.05). The starch chain‐length distributions, analyzed from enzymatically debranched starch molecules with size‐exclusion chromatography, indicated that the shorter amylopectin branches of Schooner were degraded at a faster rate than its longer amylopectin branches, which was also confirmed by the decreasing degree of branching with germination time. The changes in starch molecular structure of Grimmett grains were less apparent. The results of this study showed that barley grains containing shorter starch chains can produce sugars more quickly, which indicates that starch structure can serve as one of the specifications when selecting barley grains for brewing.     

Root architectural traits and yield: exploring the relationship in barley breeding trials

Root system architecture is fundamental to resource capture and productivity of cereal crops. Understanding the genetics modulating root development will empower plant breeders to design cultivars with optimal root systems for the target environment. Here, we investigate the genetic association between seminal root traits and yield in elite barley (Hordeum vulgare L.) germplasm. A panel of 216 breeding lines from the Northern Region Barley Breeding program in Australia, genotyped with Diversity Arrays Technology markers, were characterised for seminal root angle and number. A high degree of phenotypic variation was evident in the population, ranging from 12.0° to 89.4° and 4.8 to 6.1 for root angle and number, respectively. A quantitative trait locus for root angle (qRA-5) was detected on chromosome 5H and co-located with the previously described RAQ2. The genetic relationship between seminal root traits and yield for the panel was investigated using root phenotypes and yield data from 20 field trials. Genetic correlations with yield ranged from ??0.21 to 0.36 for root angle and from ??0.20 to 0.25 for root number. The direction and magnitude of the correlations for both root traits varied across the environments, but overall root angle was deemed more strongly associated with yield. Here we provide insight into the root phenotypes of breeding lines and deliver a first look at the genetic relationship between root architectural traits and yield in barley breeding trials.     

Speed breeding for multiple disease resistance in barley

To respond faster to the changing climate, evolving pathogens and to feed a global population of 9–10 billion by 2050, plant breeders are exploring more efficient crop improvement strategies. In this study, we applied novel methodology for rapid trait introgression to the European two-rowed barley cultivar Scarlett. Scarlett is widely-grown in Argentina and is preferred for malting and brewing, yet lacks adequate disease resistance. We used four donor lines combining multiple disease resistance (i.e. leaf rust, net and spot forms of net blotch and spot blotch) in a modified backcross strategy, which incorporated both multi-trait phenotypic screens and the rapid generation advance technology ‘speed breeding’, to develop 87 BC₁F_3:4 Scarlett introgression lines (ILs) within two years. Phenotyping this set of lines in disease nurseries located in Australia and Uruguay revealed the ILs had high levels of multiple disease resistance. Preliminary yield testing of the 12 most promising ILs in Argentina identified three ILs that were significantly higher yielding than Scarlett at Balcarce, whereas all 12 ILs displayed yield equivalent to Scarlett at Tres Arroyos. We propose that this approach is useful to rapidly transfer genes for multiple target traits into adapted cereal cultivars or pyramiding desirable traits in elite breeding material.     

In Vitro Assessment of Marine Bacillus for Use as Livestock Probiotics

Six antimicrobial-producing seaweed-derived Bacillus strains were evaluated in vitro as animal probiotics, in comparison to two Bacillus from an EU-authorized animal probiotic product. Antimicrobial activity was demonstrated on solid media against porcine Salmonella and E. coli. The marine isolates were most active against the latter, had better activity than the commercial probiotics and Bacillus pumilus WIT 588 also reduced E. coli counts in broth. All of the marine Bacillus tolerated physiological concentrations of bile, with some as tolerant as one of the probiotics. Spore counts for all isolates remained almost constant during incubation in simulated gastric and ileum juices. All of the marine Bacillus grew anaerobically and the spores of all except one isolate germinated under anaerobic conditions. All were sensitive to a panel of antibiotics and none harbored Bacillus enterotoxin genes but all, except B. pumilus WIT 588, showed some degree of β-hemolysis. However, trypan blue dye exclusion and xCELLigence assays demonstrated a lack of toxicity in comparison to two pathogens; in fact, the commercial probiotics appeared more cytotoxic than the majority of the marine Bacillus. Overall, some of the marine-derived Bacillus, in particular B. pumilus WIT 588, demonstrate potential for use as livestock probiotics.     

Gene expression signatures in neutrophils exposed to glucocorticoids: a new paradigm to help explain "neutrophil dysfunction" in parturient dairy cows

Neutrophils are the first line of immunity against most pathogens that infect cattle. These normally short-lived white blood cells develop from myeloid-lineage cells in bone marrow. Upon maturation, bone marrow neutrophils are released into the circulation where they marginate on inflamed blood vessel endothelial cells and migrate through them into the area of infection. Once migrated, neutrophils do not reenter the circulation, but rather, perform their bactericidal functions and die by apoptosis in the tissue. The cytokine and hormonal milieu of the blood and extracellular tissue fluid can influence neutrophil development and immunity-related activities, but the molecular basis of these phenotypic changes and physiological benefits or drawbacks of them are poorly understood. In the current paper, we review new gene expression information that resulted from two of our functional genomics studies designed to evaluate effects of glucocorticoid hormones on bovine neutrophils. This work provides one model to describe complex changes that occur in neutrophils as the cells respond to glucocorticoids, which might act to alter the cells' functional priorities and tip the delicate balance between health and disease during stress, including at parturition. A bovine immunobiology microarray and real time RT-PCR were used to study blood neutrophils collected during the natural surge of endogenous glucocorticoid (cortisol) in parturient dairy cows and bone marrow neutrophils collected from glucocorticoid (dexamethasone)-treated dairy steers. The gene expression signatures we observed led us to perform additional phenotyping of the neutrophils and correlation analyses, which together painted a picture suggesting that glucocorticoids have key roles in modulating neutrophil development, life span, and tissue defense functions during parturition and hormone therapy. Based on these observations, we postulate that glucocorticoids orchestrate adaptive changes in the entire neutrophil system that support increased cell numbers and longevity in blood and heightened remodeling activity in tissues, while at the same time decreasing some important antimicrobial defense activities of the cells. Thus, our functional genomics studies have enabled us to elucidate multiple consequences of neutrophil exposure to glucocorticoids, highlighting a probable role for this interaction in the induction of parturition and partly explaining why some parturient dairy cows may experience heightened incidence and severity of inflammatory diseases like mastitis.     

Pendular nystagmus in dairy cattle

In a survey of 2,932 mature dairy cattle performed over a 1-month period, we found 15 with rapid oscillation in 1 or both eyes. Nystagmus had been present since shortly after birth in 2 animals, and the age at onset was unknown in the others. The nystagmus was not associated with any other physical or neurologic problem. Pendular nystagmus apparently is benign and should not be mistaken for a sign of serious neurologic disease.