Streptomyces leidnematis n. sp., growing on two species of nematodes of the cockroach
No abstract available.
Iowa, Michigan, North Dakota↗
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Histopathologic changes of a virus-like disease of sockeye salmon
Rucker et al., (1953) described a disease of sockeye salmon ( O ncorhynchus nerka ) of possible viral etiology. First seen in Washington in 1951 with relatively minor losses, the disease recurred in 1952 killing over two million fingerling salmon with a mortality rate of 91.5 percent (Watson, 1954). In 1953, the disease was present in every sockeye salmon hatchery in the state. Rucker, Watson and their associates have demonstrated that the disease is infectious, caused by a serially-transmissible and filterable agent, and specific for one species of fish. Watson et al., (1956) have described the hematology of infected salmon. The present paper deals with the histopathology of the disease.
Transactions of the American Microscopical Society↗
Polyvinyl alcohol-fixative-adhesive for small helminths and protozoa
No abstract available.
Transactions of the American Microscopical Society↗
Some oligochaetes from Lake Michigan
Twenty-six species of Tubificidae, 12 Naididae, and 1 Lumbriculidae were found in three regions of Lake Michigan- Green Bay, the southern end of the lake proper, and the harbor at Ludington, Michigan. One new naidid species is described. Methods of identification of some species are discussed and illustrated. The abundance of oligochaetes and distribution of certain species vary with depth and location. Data are presented on the effects of the environment on the distribution of certain species. The presence or absence of some species reflected the quality of the environment; some were prevalent in polluted waters whereas others were restricted or absent. Possible changes in composition and abundance of species are outlined if organic enrichment increases in Lake Michigan.
Illinois, Indiana, Michigan, Wisconsin↗
Verification of otolith identity used by fisheries scientists for aging channel catfish
Previously published studies of the age estimation of channel catfish Ictalurus punctatus based on otoliths have reported using the sagittae, whereas it is likely they were actually using the lapilli. This confusion may have resulted because in catfishes (ostariophyseans) the lapilli are the largest of the three otoliths, whereas in nonostariophysean fish the sagittae are the largest. Based on (1) scanning electron microscope microphotographs of channel catfish otoliths, (2) X-ray computed tomography scans of a channel catfish head, (3) descriptions of techniques used to removed otoliths from channel catfish reported in the literature, and (4) a sample of channel catfish otoliths received from fisheries biologists from around the country, it is clear that lapilli are most often used for channel catfish aging studies, not sagittae, as has been previously reported. Fisheries scientists who obtain otoliths from channel catfish can use the information in this paper to correctly identify otolith age.
Transactions of the American Fisheries Society↗
Columnaris as a disease of cold-water fishes
A natural outbreak of columnaris disease among wild adult and hatchery-reared fingerling salmon in the State of Washington is described. The disease is identified by the recovery of the causative organism, Bacillus columnaris Davis, which may be readily identified by its characteristic action in forming columns on the surfaces of infected material held in a water mount on a microscope slide. The gross lesions vary in appearance according to the particular organ affected but are formed, essentially, by the progressive necrosis and disintegration of the tissues. The tissues primarily affected are skin, body musculature, and the gills. Cultivation of the causative organism in tryptone solutions is recorded. Controlled, laboratory-induced infections indicate that among the cold-water fishes, columnaris disease is of little consequence to fingerlings at water temperatures below 55° F., but becomes highly pathogenic at temperatures in excess of 70° F. Between these temperature thresholds, the degree and severity of the infection is markedly influenced by factors adverse to the host. No effective control measures have been found.
Washington↗
Evaluation of four suture materials for surgical incision closure in Siberian sturgeon
The visual and microscopic tissue reactions to the absorbable monofilament Monocryl, absorbable monofilament triclosan-coated Monocryl-Plus, absorbable multifilament Vicryl, and nonabsorbable monofilament Prolene were evaluated for their use of surgical closure in Siberian Sturgeon Acipenser baerii . Postoperative assessments were conducted at 1, 2, 8, 12, and 26 and 55 weeks to visually evaluate the surgical incision for suture retention, incision healing, erythema, and swelling. Incisions were also assessed microscopically at 1, 2, and 8 weeks for necrosis, inflammation, hemorrhage, and fibroplasia. The results indicated that incisions closed with either Vicryl or Prolene suture materials were more likely to exhibit more erythema or incomplete healing compared with those closed with Monocryl or Monocryl-Plus. The surgical implantation of a transmitter in the coelomic cavity did not significantly affect the response variables among the four suture materials. Monocryl or Monocryl-Plus were equally effective and superior to other suture materials used for closing surgical incisions in Siberian Sturgeon or closely related species of sturgeon. Furthermore, Monocryl or Monocryl-Plus may decrease the risk of transmitter expulsion through the incision, as surgical wounds appear to heal faster and exhibit less erythema compared with those closed with Vicryl.
Transactions of the American Fisheries Society↗