Organization of the flagellar apparatus and associate cytoplasmic microtubules in the quadriflagellate alga Polytomella agilis.

The organization of microtubular systems in the quadriflagellate unicell Polytomella agilis has been reconstructed by electron microscopy of serial sections, and the overall arrangement confirmed by immunofluorescent staining using antiserum directed against chick brain tubulin. The basal bodies of the four flagella are shown to be linked in two pairs of short fibers. Light microscopy of swimming cells indicates that the flagella beat in two synchronous pairs, with each pair exhibiting a breast-stroke-like motion. Two structurally distinct flagellar rootlets, one consisting of four microtubules in a 3 over 1 pattern and the other of a striated fiber over two microtubules, terminate between adjacent basal bodies. These rootlets diverge from the basal body region and extend toward the cell posterior, passing just beneath the plasma membrane. Near the anterior part of the cell, all eight rootlets serve as attachment sites for large numbers of cytoplasmic microtubules which occur in a single row around the circumference of the cell and closely parallel the cell shape. It is suggested that the flagellar rootless may function in controlling the patterning and the direction of cytoplasmic microtubule assembly. The occurrence of similar rootlet structures in other flagellates is briefly reviewed.

Relative efficiency of succinylcholine, xylazine, and carfentanil/xylazine mixtures to immobilize free-ranging moose.

We compared the efficiency of succinylcholine chloride, xylazine hydrochloride and carfentanil/xylazine mixtures in immobilizing 364 free-ranging moose (Alces alces) between 1987 and 1997 in Québec (Canada). With succinylcholine chloride (0.070, 0.062, 0.051 mg/kg of estimated body weight for calves, juveniles and adults), 63% of the 252 immobilization attempts led to complete immobilization and marking, whereas 7% of the darted animals died of respiratory paralysis during handling. The moose took an average of 13 min to lay down after darting (down time). Injection of xylazine (3.67-4.22 mg/kg) permitted sedation (the animal laid down but got up again when approached) or complete immobilization in 78% of the 40 darted adult moose, the mean down time being 8.7 min. No mortality was noted with this drug but 58% of the marked animals were only sedated. The use of RX821002A (0.058 mg/kg) as an antagonist, permitted a mean recovery time of 2.8 min after intravenous injection. With the carfentanil/xylazine mixtures (0.0071 and 0.181 mg/kg), 96% of the immobilization trials (n = 72) led to complete (88%) or partial (8%) immobilization, but 6% of the moose died several days after capture. The mean down time was 6.6 min, and injection of naltrexone (0.709 mg/kg) antagonized the effect of the immobilizing agent within 3.7 min. The respiratory rate was higher (P < 0.05) among moose immobilized with xylazine (35/min) than among those immobilized with carfentanil/xylazine mixtures (19/min) but this variation could be related to a longer pursuit time (z = 3.60; P < 0.01) and higher stress levels during handling. Rectal temperature also was higher with xylazine but the difference was small (39.7 vs. 39.3, P = 0.03) and did not differ significantly between the sexes (P > 0.05). Considering loss of materials and helicopter flight time due to non-successful marking trials, carfentanil/xylazine mixtures were the least expensive ($333 Cdn/animal).

Prediction of body composition of live and post-mortem red foxes.

A series of measurements (lengths, circumferences, skinfolds, masses and resistance) was taken on 29 red foxes (Vulpes vulpes) of both sexes before and after their death during the autumns of 1994 and 1995. Body composition of each carcass was determined by chemical analysis of homogenized samples of viscera, carcass and skin. Eight multiple regression models were then developed to predict body water, fat, protein, and mineral mass using body measurements as independent variables taken on live or dead animals. All final models were highly significant (P < 0.0001) and included three or four explanatory variables. Adjusted coefficients of determination varied between 0.95 for water mass and 0.81 for mineral mass. The models cover a wide range of conditions as percent body fat in the 29 samples varied between 1.1 and 28.4%. Our models can serve for management or research purposes with live or dead red foxes as they are quick, inexpensive and nondestructive.

The chromosomes of the Canadian Beaver Castor canadensis.

A chromosome analysis of 24 Canadian beavers, Castor canadensis Kuhl (12 males and 12 females), captured in Laurentides Park, Qébec, has been performed from preparations of blood lymphocyte and skin cultures. The chromosome number was found to be 2n = 40. Measurements were made to determine relative lengths and arm ratios of chromosomes, which are metacentric or submetacentric. Results are in agreement with those already published regarding the chromosome number, but differ in the identification of the X chromosome, and in the morphology of the Y and some autosomes. C- ad G-banding techniques allowed the precise identification of individual chromosome pairs. A detailed idiogram of G-bands is presented.

Metastatic cholangiocellular carcinoma and renal adenocarcinoma in a golden eagle (Aquila chrysaetos).

A 33-year-old captive male golden eagle (Aquila chrysaetos) was presented for necropsy with a history of emaciation and depression. The liver was severely distorted by numerous, coalescent, poorly demarcated, white firm nodules. Upon microscopic examination, these masses were found to be infiltrative and were composed of anastomosing tubular structures lined by signet-ring cells piling up in a disorderly fashion. Ultrastructurally, neoplastic cells were characterized by abundant microvilli at their apical pole and by numerous junctional complexes on lateral cell membranes. Based on morphological criteria, this tumour was classified as a poorly differentiated cholangiocellular carcinoma. Metastases were found in kidneys, testes, lungs, air sacs, pericardium, pancreas, adrenals and meninges. Additionally, two (11 and 2 mm) beige nodules were found in the cranial portion of the left kidney. Histological examination revealed locally infiltrative compact masses composed of well-differentiated tubules lined by a tall columnar epithelium without microvilli. These tumours were diagnosed as renal tubular adenocarcinomas. This is believed to be the first case of two simultaneous malignancies reported in a bird of prey.