Influence of environmental temperature on the physiological, endocrine, and immune responses in livestock exposed to a provocative immune challenge

Although livestock experience many stressors throughout their life, one of the most commonly experienced, and most difficult to control, is stress caused by fluctuations in environmental temperatures that extend beyond the thermoneutral (TN) zone for an animal. In swine, cold stress has long been recognized as a main cause of neonatal morbidity and mortality. A possible explanation for this increased morbidity and mortality may be related to their inability to generate a febrile response. Previously, we reported that the acute phase immune response, including the generation of fever, after exposure to lipopolysaccharide (LPS; Escherichia coli O111: B4; Sigma-Aldrich, St Louis, MO, USA) is substantially altered in neonatal pigs maintained in a cold environment (ie, 18°C). Neonatal pigs that were maintained in a cold environment and administered LPS experienced a period of hypothermia coupled with altered endocrine and proinflammatory cytokine responses that could prove detrimental. In cattle, we previously reported differences in the acute phase immune response of two diverse breeds of Bos taurus cattle (Angus and Romosinuano) when maintained under TN conditions and exposed to LPS. More recently we have reported that differences in the stress and immune responses of Angus and Romosinuano heifers varies, depending on whether the cattle were housed at either TN or heat stress air temperatures. Our data clearly show that even intermittent periods of heat stress similar to that experienced in production environments can have significant effects on the stress and innate immune responses of cattle. Understanding the effect of thermal stress on livestock is critical to developing and implementing alternative management practices to improve their overall health and well-being.     

Accumulation and perchlorate exposure potential of lettuce produced in the Lower Colorado River region

The Colorado River is contaminated with perchlorate concentrations of 1.5-8 microg/L, an anion linked to thyroid dysfunction. Over 90% of the lettuce (Lactuca sativa L.) consumed during the winter months in the United States is produced in the Lower Colorado River region. Studies were conducted in this region to survey the potential for lettuce perchlorate accumulation and estimate potential human exposure to perchlorate from lettuce. Total uptake of perchlorate in the above-ground plant of iceberg lettuce was approximately 5 g/ha. Exposure estimates ranged from 0.45 to 1.8 microg/day depending on lettuce types and trimming. For all lettuce types, hypothetical exposures were less than 4% of the reference dose recommended by the National Academy of Sciences. Results show the relative iodide uptake inhibition potential because of lettuce nitrate was 2 orders of magnitude greater than that associated with the corresponding trace levels of perchlorate. These data support the conclusion that potential perchlorate exposures from lettuce irrigated with Colorado River water are negligible relative to acute or long-term harmful amounts.     

Ciliates in a waste stabilization pond system in Mexico

A protozoological survey was performed on a waste-stabilization pond to isolate, identify, and determine the incidence of ciliates present in these waters. The correlation between the species found and the physicochemical parameters was investigated. One hundred and eighty samples were analyzed from February 1983 to February 1984. Free-living ciliates isolated include:Carchesium polypinum Linnaeus,Vorticella microstoma Ehrenberg,Vorticella convallaria Linnaeus,Didinium balbiani Fabré-Domergue,Amphileptus claparedei Stein,Spathidium spathula Müller,Litonotus fasciola Ehrenberg,Paramecium caudatum Müller,Paramecium aurelia Ehrenberg,Tetrahymena vorax Kidder,Tetrahymena pyriformis Ehrenberg,Cyclidium glaucoma Müller,Aspidisca costata Ehrenberg, andStylonychia putrina Stokes. The performance of the pond was predominantly anaerobic. The temperature, total alkalinity, and nitrate concentration were the most variable parameters in the system studied.     

Faster residue decomposition of brittle stem rice mutant due to finer breakage during threshing

In intensive tropical rice (Oryza sativa L.) cropping systems with short fallows, it would be advantageous that rice straw decompose fast enough to facilitate land preparation and planting of the subsequent crop. The straw of a brittle stem rice mutant of IR68 was tested for more rapid decomposition compared with non-brittle IR68 straw. The hypothesis was that the brittle mutant straw would break into smaller pieces during threshing, and that both the smaller piece size and the differences in biochemical straw composition would enable more rapid decomposition. Brittle straw broke into smaller pieces than non-brittle straw during a replicated trial of three threshing methods: hand threshing, pedal threshing, and axial-flow machine threshing. In a litter bag study to determine the effect of straw piece size on decomposition rate of each straw type over 10 weeks, smaller straw pieces decomposed faster than larger pieces as indicated by changes in amount of straw and its C/N ratio over time (P < 0.05), but there was no significant difference between straw types at the same size. It was concluded that the finer breakage of brittle straw during field operations is likely to be more important than the biochemical differences in overall residue decomposition rate.     

Direct analysis of pesticide residues in olive oil by on-line reversed phase liquid chromatography-gas chromatography using an automated through oven transfer adsorption desorption (TOTAD) interface

A fully automated on-line reversed phase liquid chromatography-gas chromatography system is described. The system uses a prototype of the automated through oven transfer adsorption desorption interface. The system is demonstrated by presenting a new rapid method for the determination of pesticide residue in olive oil, which is injected directly with no sample pretreatment step other than filtration. Methanol:water is used as the eluent in the LC preseparation step, while the LC fraction containing the pesticide is automatically transferred to the gas chromatograph. Detection limits of pesticides varied from 0.18 to 0.44 mg/L when a flame ionization detector was used. As an example, relative standard deviation and linear calibration are presented for terbutryne.     

Effect of titanium (IV) application on some enzymatic activities in several developing stages of red pepper plants

The effect of two titanium (IV) compounds, titanium ascorbate and titanium chloride, on some enzymatic activities, such as catalase, peroxidase, lipoxygenase and nitrate reductase in seeds, embryos, and seedlings and adult plants of red pepper (Capsicum annuum L.), was studied. A stimulatory effect of titanium was observed for every iron‐depending enzyme studied at all developing stages as well as for nitrate reductase but only for whole plants. This occurs because Ti⁺³/Ti⁺⁴ catalizes the activity of iron and enhances iron‐dependent enzymes.     

Effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function in anesthetized neonatal foals with induced hypotension

OBJECTIVE: To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. ANIMALS: 6 foals that were 1 to 5 days of age. PROCEDURES: 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, and baseline cardiorespiratory variables were recorded. Vasoactive drugs were administered at the low infusion rate for 15 minutes, and cardiorespiratory variables were recorded. Drugs were then administered at the high infusion rate for 15 minutes, and cardiorespiratory variables were recorded a third time. Gastric mucosal perfusion was measured by tonometry at the same time points. RESULTS: Dobutamine and norepinephrine administration improved cardiac index. Vascular resistance was increased by norepinephrine and vasopressin administration but decreased by dobutamine at the high infusion rate. Blood pressure was increased by all treatments but was significantly higher during the high infusion rate of norepinephrine. Oxygen delivery was significantly increased by norepinephrine and dobutamine administration; O2 consumption decreased with dobutamine. The O2 extraction ratio was decreased following norepinephrine and dobutamine treatments. The gastric to arterial CO2 gap was significantly increased during administration of vasopressin at the high infusion rate. CONCLUSION AND CLINICAL RELEVANCE: Norepinephrine and dobutamine are better alternatives than vasopressin for restoring cardiovascular function and maintaining splanchnic circulation during isoflurane-induced hypotension in neonatal foals.     

Pulmonary vascular reactivity of the newborn pony foal

Adult ponies develop pulmonary hypertension at altitude (Bisgard, Orr and Will 1975), but the neonatal response to acute hypoxaemia is unknown. Seven foals aged five days were instrumented with a systemic and a Swan-Ganz pulmonary artery catheter while anesthetised and intubated. Cardiac index, pulmonary (PAP) and systemic (SAP) vascular pressures were measured as the foals breathed gas mixtures with FI02 of 8 to 94 per cent. Because foramen ovale or ductus arteriosus shunts might have altered thermodilution cardiac index measurements in the stressed foals, the ratio, PAP/SAP was calculated to define relative circulatory reactivity. Three foals, two of which were full siblings, had very marked elevation of PAP/SAP from 0.6 to 1.41 at low inspired oxygen tensions. Four different foals attained maximal PAP/SAP of only 0.2 to 0.92 at similarly low oxygen tensions (P less than 0.0001). Thus, pulmonary vascular reactivity to ventilatory hypoxaemia varied greatly in pony foals of the same age. The exaggerated reactivity in related foals suggested that, as in cattle, a genetic predisposition to develop reactive pulmonary hypertension under hypoxaemic stress may exist.     

Evaluation of the stability of Ostertagia ostertagi ELISA microtitre plates over time using cow milk samples

The objective of this study was to assess the stability of ELISA plates prepared with one of three blocking agents and used with one of two conjugates at various time intervals after preparation of the plates. Two of the blocking agents used were commercially available: one termed stabilgaurd (stab) and one manufactured by SVANOVA Biotek AB Inc. (svan). The third blocking agent used was bovine serum albumin (bsa). A polyclonal rabbit anti-bovine IgG (poly) and an anti-bovine IgG monoclonal (mono) conjugate were used. Eighteen composite individual cow milk samples collected late in lactation (200-400 days in milk) were used in this study. An indirect microtitre plate ELISA that used the Ostertagia ostertagi antigen was used to quantify antibodies against the parasite, present in the milk samples. Each of six blocking agent/conjugate combinations (called systems) were used to test 18 milk sub-samples at 1, 4 and 24 weeks after blocking the plates. Plates blocked with stab and svan were kept at room temperature and an additional set were incubated at 37 degrees C so as to mimic long term storage (about 1 year) and tested only once at 4 weeks. Those blocked with bsa were frozen at -20 degrees C. Concordance correlation coefficients (CCC) and reproducibility were used to assess the agreement between test results conducted on the same milk sample at the various test-times using a particular system. Generally, there was good agreement between tests conducted at different times for all systems. However, the svan-mono and bsa-poly systems had the best agreement with overall CCC values of 96% and 93%, respectively. The svan-poly system had the lowest CCC of 75%. The CCC and reproducibility ranked the systems in a similar way. The high CCC between tests done using plates kept at room temperature and ones incubated at 37 degrees C, suggested that plates would be stable up to a year after blocking. The storage of plates blocked with svan and stab agents under room temperature, makes them more convenient to use and transport relative to bsa-blocked plates that have to be frozen.     

Identification of Volatiles of the Dinoflagellate Prorocentrum cordatum

The dinoflagellate Prorocentrum cordatum, often called P. minimum, is a potentially toxic alga found in algal blooms. Volatile compounds released by the alga might carry important information, e.g., on its physiological state, and may act as chemical messengers. We report here the identification of volatile organic compounds emitted by two strains, xenic P. cordatum CCMP 1529 and axenic P. cordatum CCMP 1329. The volatiles released during culture were identified despite their low production rates, using sensitive methods such as open-system-stripping analysis (OSSA) on Tenax TA desorption tubes, thermodesorption, cryofocusing and GC/MS-analysis. The analyses revealed 16 compounds released from the xenic strain and 52 compounds from the axenic strain. The majority of compounds were apocarotenoids, aromatic compounds and small oxylipins, but new natural products such as 3,7-dimethyl-4-octanolide were also identified and synthesized. The large difference of compound composition between xenic and axenic algae will be discussed.