Reactivation of broccoli peroxidases: structural changes of partially denatured isoenzymes

Structural changes involved in the reactivation of peroxidases (PODs) from broccoli and horseradish (HRP) following heat denaturation were investigated by using circular dichroism and absorption spectroscopy. Cooling heat-treated enzymes resulted in rapid refolding of the secondary structure into an inactive structural species, similar in conformation to the native enzyme. Reassociation of heme to the refolded peroxidase, as well as molecular rearrangement of the structure around the heme, occurs during incubation at approximately 25 degrees C and results in the return of biological activity. The secondary structure of neutral broccoli POD (N) is relatively heat labile, resulting in a rapid loss of activity, but the level of reactivation is high because the structure at the heme pocket is relatively stable. Acidic broccoli POD and HRP are more heat stable than N, but have a low degree of reactivation. Loss of activity is due primarily to alteration of the structure at the heme pocket. Effects of bovine serum albumin and pH on reactivation of PODs are also discussed. Keywords: Peroxidase; reactivation; horseradish; broccoli; circular dichroism; absorption spectroscopy.     

Impacting Librarianship and Veterinary Medicine: History of the Veterinary Medical Libraries Section of the Medical Library Association from 1974 to 2014

This article discusses the Veterinary Medical Libraries Section (VMLS) of the Medical Library Association (MLA), its impacts on both librarianship and veterinary medicine during its 40-year history, how it achieved those impacts, relationships, selected projects, and organizational changes through the years. A listing of publications about veterinary librarianship and VMLS products is available on the VMLS website (Veterinary Medical Libraries Section, 2014).     

Mantle discontinuity structure beneath the southern east pacific rise from P-to-S converted phases

Receiver functions derived from teleseismic body waves recorded by ocean-bottom seismometers on the southern East Pacific Rise reveal shear waves converted from compressional waves at the mantle discontinuities near 410- and 660-kilometer depth. The thickness of the mantle transition zone between the two discontinuities is normal relative to the global average and indicates that upwelling beneath the southern East Pacific Rise is not associated with an excess temperature in the mantle transition zone.     

Comparison of 3,5,3′-triiodo-L-thyronine and L-thyroxine absorption from the intestinal lumen of the fasted rainbow trout,Oncorhynchus mykiss

The absorptions of 3,5,3-triiodo-L-thyronine (T₃) and L-thyroxine (T₄) from the intestinal lumen of the rainbow trout were compared in vivo. Tracer doses of [¹²⁵I]T₄ (⁺T₄) or [¹²⁵I]T₃ (^*T₃) were injected through an anal cannula into the duodenum of trout fasted for 3 days at 12°C, and radioactivity was measured in blood and tissues at 4–48 h. ^*T₃ was removed more extensively than ^*T₄ from the intestinal lumen and more radioactivity was absorbed into the blood and tissues of u+T₃-injected trout than ^*T₄-injected trout. HPLC analysis showed that a high proportion of the radioactivity in the plasma, liver, kidney and intestinal lumen of ^*T₃-injected trout remained as the parent ^*T₃. However, in ^*T₄-injected trout most plasma radioactivity was in the form of ¹²⁵I^–, and by 24 h a high proportion of luminal radioactivity was ¹²⁵I^–. By 48 h, over 4% of the injected ^*T₃ and 1% of the injected ^*T₄ dose resided in the gall bladder, primarily as derivatives of ^*T₃ or ^*T₄. We conclude that T₃ is absorbed more effectively than T₄ from the intestinal lumen of fasted trout, indicating the potential for an enterohepatic T₃ cycle.     

Methionine-containing proteins in twoPhaseolus vulgaris cultivars with different methionine bioavailabilities

The full utilization of legumes as human food is limited by a deficiency of sulfur amino acids, low protein digestibility, low methionine bioavailability and the presence of anti-nutritional factors. A new cultivar ofPhaseolus vulgaris (Carioca 80) has 56.8% available methionine, compared with 29.3% availability in the parent cultivar Carioca. The total methionine content, denaturing gel electrophoretic patterns of methionine-containing proteins, and the percentage of phaseolins (the major storage proteins in Phaseolus) relative to the total protein are similar in the two cultivars. Although the digestibility of the two cultivars is similar, the increased biological value of Carioca 80 may indicate that there are differences in overall bean composition that affect protein hydrolysis and utilization. We suggest the tentative explanation that this is due to differences in the distribution of methionine in the methionine-containing proteins of the two cultivars.     

The effects of two non‐steroidal anti‐inflammatory drugs on the mobility of laying hens with keel bone fractures

ObjectiveInvestigate the effects of administration of meloxicam and carprofen on the mobility of hens with and without keel fractures.Study designWithin each of two experiments a ‘blinded’ randomised cross over design whereby birds received either the test drug (carprofen or meloxicam) or saline.AnimalsTwo groups of Lohman Brown hens with and without keel bone fractures.MethodsThe first group (n = 63) was treated with carprofen 25 mg kg⁻¹ and saline subcutaneously, twice. The second group (n = 40) was treated with meloxicam (5 mg kg⁻¹) and saline subcutaneously. The latency of birds to fly down from perches 50, 100 and 150 cm above the ground was measured after each treatment. Data from experiment 1 and 2 were analysed separately; the effects of drug treatment compared with saline on landing time for birds with and without keel bone fractures were evaluated using MLwiN.ResultsIn both experiments latency to fly down from perches was longer in hens with keel fractures and there was a significant interaction between perch height and fracture status. For carprofen, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took (mean ± SD) 2.5 ± 2.9, 6.8 ± 9.7 and 11.5 ± 13.2 seconds respectively to fly down compared with 1.3 ± 0.5, 2.3 ± 1.2 and 4.2 ± 3.1 seconds for birds without fractures. For meloxicam, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took 2.9 ± 2.5, 49.8 ± 85.4 and 100.3 ± 123.6 seconds respectively compared with 0.7 ± 0.5, 2.5 ± 7.1 and 3.0 ± 4.6 seconds to fly down for birds without fractures. There was no significant effect of carprofen or meloxicam treatment.Conclusion and clinical relevanceThese data provide further confirmation that keel fractures reduce the willingness of birds to move from perches.     

Disposal and disease rates in British dairy herds between April 1998 and March 2002

Data derived over four years from 434 dairy herds in 1998/99 to 244 in 2001/02 revealed average disposal rates of 22.6 per cent per year, half of which were for poor fertility, mastitis and lameness. The quartile of herds with the lowest disposal rates sold an average of 11.5 per cent annually and the quartile with the highest rates sold 35.5 per cent. Average annual disease rates over the four years were as follows: for assisted calving 7.8 per cent, for digestive disease 1.2 per cent, for ketosis 0.5 per cent, for hypomagnesaemia 0.5 per cent, for hypocalcaemia 5.0 per cent and for injuries 0.8 per cent. The incidence of mastitis increased from 36.0 to 43.3 per cent of cows per year. The incidence of lameness decreased from 23.3 per cent in 1998/99 to 20.7 per cent in 2000/01 but increased to 21.9 per cent in 2001/02. Data received from the same 219 farms during the first three years showed no effective differences from the full set of data for each of the three years. The lowest annual incidences of mastitis and lameness on individual farms were below 7 per cent and 2.5 per cent, respectively. In general, housing cows in cubicles was associated with a greater risk of lameness, and housing them in straw yards with a greater risk of mastitis. However, some of the lowest rates of lameness were recorded in cubicle-housed cows and some of the lowest rates of mastitis were recorded in cows housed in yards. Larger herds were not associated, in general, with higher rates of mastitis.     

Effects of N‐acetyl‐cysteine and N‐acetyl‐cysteine‐amide Supplementation on In Vitro Matured Porcine Oocytes

This study was conducted to evaluate the effects of different concentrations of the antioxidant N‐acetyl‐cysteine (NAC) supplemented to the maturation medium on porcine embryo development. Concentrations of NAC and its synthetic derivative, NAC‐amide (NACA) were evaluated for effects on nuclear maturation, fertilization success and embryo development. Concentrations of NAC (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 5.0 mm ) were supplemented to maturing oocytes, and embryo development was analysed at 48 and 144 h post‐fertilization. There were no differences among cleavage rates for any of the treatment groups. Blastocyst formation for 1.5 mm NAC (56.5 ± 9.2%) was higher (p < 0.05) than all other supplementations. There were no differences in nuclear maturation or fertilization or in cleavage rates when comparing 1.5 mm NAC and 1.5 mm NACA supplementation to the control. Blastocyst formation for 1.5 mm NAC (44.4 ± 4.7%) and 1.5 mm NACA (46.2 ± 3.4%) supplementation were higher (p < 0.05) than the control (32.1 ± 6.2%) oocytes. These results indicate that supplementing 1.5 mm of NAC or NACA to the oocyte maturation medium increased the percentage of viable embryos reaching the blastocyst stage of development.