A Single Sea Lamprey Attack Causes Acute Anemia and Mortality in Lake Sturgeon

Abstract

The effects of sea lamprey Petromyzon marinus parasitism on hematological variables have not been quantified for lake sturgeon Acipenser fulvescens. Our study objectives were to (1) assess changes in lake sturgeon hematology immediately after a single sea lamprey attack and after a 2-week recovery period and (2) assess changes in the histological condition of major hematopoietic organs. Lake sturgeon from four size-groups (470–570, 570–650, 650–760, and 950–1,500 mm fork length) were individually subjected to a sea lamprey attack in a series of 55 experimental trials. Survival of lake sturgeon after a single sea lamprey attack was size dependent, with fish in smaller size-groups exhibiting higher direct and indirect mortality than individuals in larger size-classes. The most sensitive blood chemistry variable was hematocrit: each 1% decline in hematocrit resulted in a 5.1% increase in mortality risk. Other important variables were plasma protein level, with a 10-g/dL decline resulting in a 4.2% increase in mortality risk; and hemoglobin, with a 1-g/dL decline resulting in a 2.9% increase in mortality risk. Most of the surviving lake sturgeon were unable to restore hemoglobin, hematocrit, and plasma protein to pre-attack levels by the end of the 2-week recovery period. We developed an index of histological spleen condition, which indicated that short-duration (<5-d) sea lamprey attachments depleted red blood cell reserves faster than longer-duration attacks. Our study results indicate that sea lamprey parasitism has the potential to induce acute anemia in lake sturgeon and that nonlethal attacks on smaller (<760-mm) fish can have serious physiological implications.

Received August 3, 2011; accepted February 2, 2012.     

Managing anthelmintic resistance: Modelling strategic use of a new anthelmintic class to slow the development of resistance to existing classes

AIM: To test the hypothesis that a single strategic treatment with a new class of anthelmintic could slow the development of resistance to existing classes of anthelmintic.

METHODS: An existing model was used to simulate nematode parasite dynamics and the development of anthelmintic resistance. Variations on a five-drench preventive programme of treatments for lambs, in which either zero, the first, third or fifth treatment was substituted with a different class of drug, were compared for the time to reach treatment failure (defined as efficacy <95%). The sensitivity to variations in the death rate of adult worms, that varied from 1 to 5%, and the dominance of resistance genes were also assessed.

RESULTS: Replacing one of the five treatments with a different class of anthelmintic almost always slowed the development of resistance, and was never worse than using the same drug for all treatments. Further, there were large differences in the relative time to treatment failure depending on which treatment was substituted. Changing the first treatment always had the least benefit, whereas changing the fifth treatment always had the greatest. This pattern was independent of the daily death rate of adult worms, and was not influenced by the dominance of resistance under treatment.

CONCLUSIONS: The results indicated that strategic substitution of a single treatment with a new class of anthelmintic, at the end of a series of preventive treatments to lambs using an existing class, could slow the further development of resistance to the latter. This strategic use of a new anthelmintic class has the potential to greatly extend the life of existing anthelmintics if these are still effective.     

Some anaemias of farm livestock

Extract

Anaemia is a reduction below normal in the concentration of circulating haemoglobin. In some anaemias, particularly in iron deficiency, the red cell count may be normal. Many diseases of farm livestock are characterised by anaemia as their main clinical sign, while other diseases, although accompanied by anaemia, may have more prominent clinical indicators. An aemia is rarely a primary disorder.     

The refractometric determination of the total protein concentration in some animal plasmas

Abstract

Extract

Refractometry has been used for serum or plasma total, protein determination since the beginning of this century and while at times the value and accuracy of the technique has been open to question (see Lines and Raine, 1970a Babul, J. and Stellwagen, E. 1969. Measurement of protein concentration with interference optics. Analyt. Biochem., 28: 216–221. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar],b Barry, K. G., McLaurin, A. W. and Parnell, B. L. 1960. A practical temperature-compensated hand refractometer (the TS-meter). Its clinical use and application in estimation of total serum proteins. J. lab. din. Med., 55: 803–808.  [Google Scholar]), many studies have shown close agreement between refractometric determination of serum total protein and estimation by such techniques as the Biuret method and the Kjeldahl nitrogen determination (Lines and Raine, 1970b Drickman, A. and McKeon, F. A. 1962. Determination of total serum protein by means of the refractive index of serum. Am. f. clin. Path., 38: 392–396.  [Google Scholar]; Barry et al., 1960 Harboe, M. 1959. A method for determination of haemoglobin in plasma by near-ultraviolet spec-trophotometry. Scand, J. clin. lab. Invest., 11: 66–70. [Taylor &; Francis Online] , [Google Scholar]; Drickman and McKeon, 1962 Henry, R. J. 1974. Clinical Chemistry, 177–177. New York, Evanston and London: Harper &; Row. John Weatherhill, Tokyo [Google Scholar]).     

Spawning movements of humpback whitefish in interior Alaska rivers

This study was conducted to describe the spawning movements and identify spawning areas for humpback whitefish Coregonus pidschian in the Minto Flats–Chatanika River complex, Alaska, during 2008 and 2009. Radio transmitters were surgically implanted in humpback whitefish in 2008 (N = 60) and 2009 (N = 100), and fish positions were determined through a combination of boat and aerial surveys and fixed receiving stations. Two spawning areas were identified: one in the Chatanika River downstream of the Elliot Highway Bridge and the other in the Tanana River near Fairbanks. Humpback whitefish dispersed from the wetland complex of Minto Flats in June, moved upstream through late August, arrived at the spawning areas in early September and began moving downstream in early October. In 2009, spatially segregated movements were observed when approximately 40% of the radio‐tagged humpback whitefish moved to the Tanana River, suggesting that humpback whitefish in Minto Flats are comprised of mixed spawning stocks. These study results provide a complete account of humpback whitefish movements and their associated spawning habitats, which will allow for better‐informed management strategies.     

Sensitivity of Mycosphaerella fijiensis, Causal Agent of Black Sigatoka of Banana, to Propiconazole

ABSTRACT One hundred monoascosporic isolates of Mycosphaerella fijiensis were collected in February and November 1994 from each of two banana (Musa spp.) plantations in Costa Rica. Locations at San Pablo and Coopecariari had been sprayed with propiconazole for the past 7 years to control black Sigatoka. One hundred monoascosporic isolates from a third location, San Carlos, with no history of fungicide use, also were tested for sensitivity to propiconazole. Fifty percent effective concentration (EC(50)) values were calculated for individual isolates by regressing the relative inhibition of colony growth against the natural logarithm of the fungicide concentration. In the February sample, the mean EC(50) values for San Pablo and Coopecariari populations were 0.06 and 0.05 mug a.i. ml(-1), respectively, which were not statistically different (P = 0.05). The mean EC(50) value of the population at San Carlos was 0.008 mug a.i. ml(-1), which was significantly lower (P = 0.001) than the mean EC(50) values obtained at San Pablo and Coopecariari. Frequency distributions of EC(50) values of isolates from the three populations collected in February showed that 80% of isolates from San Pablo and Coopecariari had EC(50) values greater than the highest EC(50) value from San Carlos, indicating a significant shift in reduced sensitivity to propiconazole. Isolates collected in November 1994, after eight treatments of propiconazole at San Pablo and Coopecariari, showed a significant increase in mean EC(50) values compared with the means observed in February. The high proportion of isolates with reduced sensitivity to propiconazole may account for the unsatisfactory control of black Sigatoka between 1992 and 1993 in the two banana plantations at San Pablo and Coopecariari.     

Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum

Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia.