Apoplastic redox metabolism: Synergistic phenolic oxidation and a novel oxidative burst

The plant apoplast is an important mediator of communication between the cell cytoplasm and its surroundings. Plant cell suspensions offer a convenient model system to gain insight into apoplastic physiology. Here, we describe a novel phenomenon that took place when two naturally occurring phenolics were added together to either soybean or tobacco cell suspensions. Acetosyringone (AS) and/or hydroxyacetophenone (HAP), phenolics found in the extracellular/apoplast of tobacco cells, were added to soybean or tobacco cell suspensions undergoing an oxidative burst. Individually, AS appeared to be utilized as a typical peroxidase substrate to scavenge hydrogen peroxide, while HAP was utilized at a much lower rate. However, when added together the rate of utilization of both phenolics increased and surprisingly resulted in the production of hydrogen peroxide. We have further characterized this novel phenomenon in suspension cells. This study demonstrates that certain phenolics in plants can cause co-oxidation which, as in animals, could alter the structure and bioactivity of surrounding phenolics.     

Spermatic and oxidative profile of domestic cat (Felis catus) epididymal sperm subjected to different cooling times (24, 48 and 72 hours)

Cooling stored epididymal samples for several days allows facilities to transport and process genetic material post‐mortem. Improvements to this practice allow the preservation of sperm from domestic cats, which are the ideal study model for wild felids. However, the modifications in spermatic features and the oxidative profile are not fully understood in cats. This information is necessary for the development of biotechniques, such as new extenders for cryopreservation. Therefore, the purpose of this study was to evaluate the spermatic and oxidative profile in samples from the epididymal cauda of domestic cats cooled at 5°C for 24, 48 and 72 hr. Spermatozoa were collected from the epididymis cauda. Evaluations consisted of computer‐assisted sperm analysis (CASA), plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, sperm DNA integrity (toluidine blue), mitochondrial activity (3′3 diaminobenzidine), activity of the antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), measurement of lipid peroxidation (TBARS) and protein oxidation. A decrease in sperm motility parameters was observed after 72 hr of cooling (i.e. total and progressive) with a higher percentage of minor (37.7 ± 6.3%) and total defects (53.4 ± 6.3%). Additionally, a decrease in high mitochondrial activity (Class I: 16.6 ± 2.2%) occurred after 72 hr. The decrease in motility rates after a long cooling time probably was caused by the increase in sperm abnormalities. A long cooling time causes cold shock and mitochondrial exhaustion, but there was no observed change with the oxidative stress condition. Therefore, cat epididymal sperm stored at 5°C appear to maintain a high quality for up to 48 hr of cooling time.     

A fast,low‐cost and efficient method for the diagnosis of sperm DNA fragmentation in several species

Sperm DNA fragmentation is a condition that interferes directly in the reproductive efficiency. Currently, there are several methods for assessing the sperm DNA integrity, such as Alkaline Comet, TUNEL and Sperm Chromatin Structure Assay. However, many of these techniques are laborious and require high‐precision equipment. Thus, the development of new techniques can optimize the evaluation of sperm DNA damage. Therefore, the aim of this study was to standardize the toluidine blue (TB) stain technique for the analysis of DNA fragmentation of dog, cat, bull, stallion and ram spermatozoa. For this purpose, we used six animals of each specie (n = 30), in reproductive age. Sperm was collected by different methods according to the particularities of each species, and such samples were divided into two aliquots: a sperm sample was kept at 5°C (considered as intact sperm DNA), and the remaining samples were submitted to the induction of DNA fragmentation by exposure to ultraviolet light for 4 hr. Samples were then mixed with the intact sample to obtain known and progressive proportions of sperm with fragmented DNA (0%, 25%, 50%, 75% and 100%). Semen smears were performed and subjected to staining with TB. Blue‐stained spermatozoa were considered to have DNA fragmentation. We observed high linear regression coefficients between the expected proportion of damaged DNA and the results of TB for dog, cat, ram, bull and stallion samples. In conclusion, TB stain was considered a fast and effective technique for the study of spermatozoa DNA in several species.     

Disposal and disease rates in 340 British dairy herds

Data derived from 340 dairy herds, mainly in southern England, between April 1998 and March 1999, showed that the average total culling rate was 22.1 per cent, with 5.6 per cent for infertility, 3.6 per cent for mastitis, 1.7 per cent for lameness, 2.0 per cent for poor milk yield, 3.7 per cent for age and 5.5 per cent for miscellaneous reasons which included death. The average annual rate of assisted calvings was 8.7 per cent, of injury 0.9 per cent, digestive disease 1.3 per cent ketosis 0.4 per cent, hypomagnesaemia 0.7 per cent, hypocalcaemia 5.3 per cent, mastitis 36.6 per cent, and lameness 23.7 per cent. There was a significant association (P<0.001) between higher rates of mastitis in cows housed in straw yards as opposed to cubicles and also between higher rates of lameness in cows housed in cubicles as opposed to yards (P<0.015). However, there were farms with low rates of mastitis in cows kept in straw yards and low rates of lameness in cows kept in cubicles. Larger herds tended to have more problems with lameness and higher bulk milk somatic cell counts (BMSCC). There was a positive association between BMSCC and mastitis rate.     

Renal myxozoanosis in weedy sea dragons, Phyllopteryx taeniolatus (Lacepède), caused by Sinuolinea phyllopteryxa n. sp.

Renal myxozoanosis was diagnosed histologically in 11 captive, wild caught, adult weedy (common) sea dragons, Phyllopteryx taeniolatus, from three separate public aquaria in the United States. Myxozoan spores were visible in wet mounts of kidney tissue and were associated with renal tubular dilatation and tubular epithelial cell hypertrophy. Light and electron microscopy revealed spore morphology consistent with the genus Sinuolinea. Spores were spheroidal, slightly dorso-ventrally compressed, length (L) 17.1 x width (W) 16.4 x thickness (T) 15.6 microm, with two shell valves joined at a distinct, sinuous sutural ridge, and had two nearly spherical polar capsules, L 5.5 x W 5.0 microm, with five to seven turns of the polar filament. There were no extra-valvular ridges or protrusions. DNA sequencing required the design of three new primers that yielded 1740 bp of 18S ribosomal DNA sequence. The parasite was determined to be novel based on morphological and molecular data, and was given the name Sinuolinea phyllopteryxa after its vertebrate host.     

Serum levels of reproductive steroid hormones in captive sand tiger sharks, <Emphasis Type="Italic">Carcharias</Emphasis><Emphasis Type="Italic">taurus</Emphasis> (Rafinesque), and comments on their relation to sexual conflicts

Levels of reproductively-related steroids were determined in captive male sand tiger sharks, Carcharias taurus, maintained at two institutions: SeaWorld Adventure Park Orlando and the National Aquarium in Baltimore. Sexual conflicts were absent at the former, but were documented at the latter. Serum titers of 17β-estradiol, progesterone, testosterone, and 5α-dihydrotestosterone were determined via radioimmunoassay in adult male sharks from 1988 to 2000. Sampling overlap between the two institutions occurred for 3 months of the year, but steroid concentrations were compared only for April due to the occurrence of sexual conflicts in the sharks at the National Aquarium in Baltimore in that month. For April, testosterone and dihydrotestosterone were significantly higher in the SeaWorld males, and progesterone was significantly higher in the National Aquarium in Baltimore males, while estradiol was not significantly different. Steroid levels were also determined from serial samples taken monthly over 17 months from three male sharks and one female shark at the National Aquarium in Baltimore in 2001–2002 and were compared with corresponding observed sexual conflicts. The steroid levels obtained showed distinct annual hormonal cycles in the male sharks and corroborated a biennial cycle for the single serially-sampled female shark. Furthermore, the steroid levels for individual males correlated with sexual conflicts as well as their position within the male dominance hierarchy. As this species is depleted in some regions globally, insight into the steroid profile of mature sand tiger sharks is important for a greater understanding of the relationship between their reproductive physiology and behavior, and may aid in captive management and reproduction. L. E. L. Rasmussen—Deceased.     

Promotion of pistillate flowering inCucurbita by 2-chloroethylphosphonic acid

Summary All accessions tested of four cultivated species ofCucurbita responded to seedling treatment with 250 ppm 2-chloroethylphosphonic acid by developing only pistillate flowers for an extended period. This growth regulator is a promising means of facilitating hybrid seed production of squash. A similar treatment did not induce flowering of wild species ofCucurbita that were vegetative under the environmental conditions of the experiment.Approved by the Director of the New York State Agricultural Experiment Station for publication as Journal Paper No. 1737.     

Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia

ObjectiveTo determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia.Study designExperimental study.AnimalsSeven healthy warmblood horses, aged 3–11 years, weighing 470–565 kg.MethodsMeasurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg⁻¹ minute⁻¹) over ten minutes followed by norepinephrine (0.1 mg kg⁻¹ IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg⁻¹ IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHgResultsA total of 245 paired measurements of systolic (SAP), mean (MAP) and diastolic (DAP) pressures were obtained. The HDO device underestimated blood pressure at hypertensive and normotensive levels and overestimated blood pressure at hypotensive levels. Best agreement was obtained for SAP and MAP within normotensive limits. At normotension, bias ± standard deviation for SAP, MAP and DAP were 0.1 ± 19.4 mmHg, 0.5 ± 14.0, 4.7 ± 15.6, respectively. At high pressure levels bias and SD were 26.1 ± 37.3 (SAP), 4.2 ± 19.4 (MAP), 1.5 ± 16.8 (DAP) and at low pressures -20.0 ± 20.9 (SAP), -11.4 ± 19.6 (MAP), -4.7 ± 20.1 (DAP), with HDO measurements at a MAP <50 mmHg often failing.Conclusion and clinical relevanceGood agreement with invasive arterial blood pressures was obtained with HDO at normotensive levels in horses. At high and low pressure ranges HDO was unreliable. Therefore, if haemodynamic instability is expected, invasive measurement remains preferable.