Plasma and liver concentrations of aP-tocopherol in weaner sheep after vitamin E supplementation

Changes in the plasma and liver concentrations of alpha-tocopherol in sheep kept in an animal house, grazed on pasture, grazed on pasture and fed an oat/lupin grain supplement, or grazed on toxic lupin stubble were monitored following no, oral or intramuscular administration of alpha-tocopherol. It was concluded that intramuscular administration was most effective because it caused longer periods of elevated plasma alpha-tocopherol concentrations in most situations investigated and consistently higher concentrations of alpha-tocopherol in the liver, compared to oral administration. The dose rates of alpha-tocopherol given, the vehicle for alpha-tocopherol in the injectable preparation, the different diets consumed and the concurrent occurrence of lupinosis all influenced the results. In spite of this a significant positive correlation existed between the terminal liver and plasma alpha-tocopherol concentrations.     

The prevalence of Dirofilaria immitis in dogs in Sydney

Four hundred and four dogs from 9 pounds in Sydney were examined for circulating microfilariae and antigens of Dirofilaria immitis. One hundred of these were also examined post mortem for adult heartworms. The prevalence of infection in the 404 dogs as shown by serology was 11.4%, and 5.9% had circulating microfilariae of D immitis. Adult heartworms were present in 15 of 100 dogs. Dipetalonema reconditum microfilariae were present in 3.7% of dogs. Dirofilariosis is still a common and important parasite of dogs in the Sydney region and chemoprophylaxis is recommended.     

Vaginal isolation of beta‐haemolytic Streptococcus from bitches with and without neonatal deaths in the litters

The aim of the study was to identify beta‐haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty‐one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta‐haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex^®) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta‐haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post‐partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.     

Effect of calpastatin on degradation of myofibrillar proteins by mu-calpain under postmortem conditions.

To improve our understanding of the regulation of mu-calpain activity in situ during postmortem storage of muscle, the effect of different calpastatin levels on proteolysis of myofibrillar proteins by mu-calpain in a system closely mimicking postmortem conditions was studied. Increasing the amount of calpastatin in the incubations limited both the rate and extent of proteolysis of myofibrillar proteins and autolysis of mu-calpain. Excess calpastatin (i.e., a mu-calpain:calpastatin ratio of 1:4) did not inhibit proteolysis completely. Western blot analysis revealed that proteolysis of myofibrillar proteins virtually ceased after 7 d of incubation, despite the presence of partly autolyzed, therefore seemingly active, mu-calpain. A series of incubations of autolyzed mu-calpain revealed that the autolyzed form of this enzyme is unstable at an ionic strength observed in postmortem muscle. The possible significance of these results in terms of the regulation of mu-calpain activity in postmortem muscle is discussed.     

Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores

Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500 degrees C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35 degrees to 80 degrees C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140 degrees C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.     

Particulate metmyoglobin reducing activity and its relationship with meat color

There is controversy about the effect of storage time on metmyoglobin (MetMb) reducing activity in the sarcoplasmic fraction of meat and the role of this reducing activity in maintaining the color of red meat. The presence of metmyoglobin reducing activity in the myofibrillar fraction of muscle extracts was investigated as a possible reason for this controversy. NADH-dependent MetMb reducing activity was found in the particulate fraction of meat following sedimentation of a meat homogenate at 35 000g. There was 5.8 times more MetMb reducing activity in the particulate fraction compared with that of the sarcoplasmic (supernatant) fraction. The presence of metmyoglobin reducing activity in the myofibrils (MMRA), defined as the activity in the sediment after centrifugation of a meat homogenate at 2 000g, was confirmed. The myofibrillar fraction contained 63% of the total MetMb reducing activity available in the meat. The relationship between muscle MetMb reducing activities and meat color parameters was investigated in a beef patties system. The particulate MetMb reducing activity (PMRA) in beef patties was found to be a good indicator of the total metmyoglobin reducing activity in meat and was positively correlated with the color parameters of the patties, suggesting that PMRA may be associated with red meat color of meat patties.     

Acute Toxicity and Anesthetic Effects of Clove Oil in Penaeus semisulcatus under Various Water Quality Conditions

Acute toxicity and anesthetic effects of clove oil were studied in P. semisulcatus (1.8–2.1 g body weight). The EC₅₀ 1-h (the concentration effective for 50% of test animals), LC₅₀ 1-h (the concentration lethal to 50% of test animals after 1 h) and LC₅₀ 24-h (the concentration lethal to 50% of test animals after 24 h) were calculated at concentrations of 25, 130 and 30 mg/l, respectively, at 30°C, salinity 40 ppt, pH 8.6 and dissolved oxygen >6 mg/l. Generally, with increasing concentrations of clove oil, the times required for sedation and anesthesia decreased, while the recovery times increased. At concentrations 50, 100, 150 and 200 mg/l under temperature of 30°C and salinity of 40 ppt, the times required for sedation were 6 ± 0.2, 2.5 ± 0.3, 2 ± 0.08 and 0.5 ± 0.08 min, while times required for complete recovery were calculated to be 4.5 ± 0.3, 5.5 ± 0.17, 6.5 ± 0.25 and 11 ± 0.38 min, respectively. Also, the times required for deep anesthesia were 20 ± 1, 5 ± 0.5, 3 ± 0.4 and 2.2 ± 0.5 min in the above concentrations, while the times required for complete recovery were 10 ± 1, 11 ± 1.5, 14 ± 2.2 and 16 ± 3 min, respectively. Furthermore, considering the times to sedation, deep anesthesia and recovery at different temperatures of 20°C, 25°C, 30°C and 35°C and salinities of 25, 30, 35, 40 and 48 ppt; the combinations of salinity plus temperature and clove oil concentration plus salinity had the greatest and the least effects.     

Micro-calpain is essential for postmortem proteolysis of muscle proteins

The objective of this investigation was to test the hypothesis that -calpain is largely responsible for postmortem proteolysis of muscle proteins. To accomplish this objective, we compared proteolysis of known muscle proteins in muscles of wild type and micro-calpain knockout mice during postmortem storage. Knockout mice (n = 6) were killed along with control mice (n = 6). Hind limbs were removed and stored at 4 degrees C. Muscles were dissected at 0, 1, and 3d postmortem and subsequently analyzed for degradation of nebulin, dystrophin, metavinculin, vinculin, desmin, and troponin T. In a separate experiment, hind limb muscles from knockout (n = 4) and control mice (n = 4) were analyzed at 0, 1, and 3 d postmortem using casein zymography to confirm that mu-calpain activity was knocked out in muscle and to determine whether or not m-calpain is activated in murine postmortem muscle. Cumulatively, the results of the first experiment indicated that postmortem proteolysis was largely inhibited in micro-calpain knockout mice. The results of the second experiment established the absence of micro-calpain in the muscle tissue of knockout mice and confirmed the results of an earlier study that m-calpain is active in postmortem murine muscle. The results of the current study show that even in a species in which m-calpain is activated to some extent postmortem, micro-calpain is largely responsible for postmortem proteolysis. This observation excludes a major role for any of the other members of the calpain family or any other proteolytic system in postmortem proteolysis of muscle proteins. Therefore, understanding the regulation of micro-calpain in postmortem muscle should be the focus of further research on postmortem proteolysis and tenderization of meat.