Consequences of injuries on survival and reproduction of common bottlenose dolphins (Tursiops truncatus) along the west coast of Florida

Accurate identification of human‐induced injuries that lead to death or interfere with reproduction is important for marine mammal management, as deaths exceeding established limits can lead to restrictions on fisheries or vessel operations. The fates of cetaceans last seen swimming with attached gear, particularly in pelagic fisheries, or with vessel strike lacerations, have been difficult to predict. Survival and reproduction data from long‐term research on resident common bottlenose dolphins near Sarasota, Florida were examined relative to consequences of fishing gear ingestion, line entanglements, vessel strikes, and amputations of unknown origins. Fishing hooks embedded in the throat, goosebeak, or esophagus, or line wrapped around the goosebeak, generally lead to death. Multiple, constrictive line wraps around fin insertions can lead to amputation, blood loss, impaired mobility, or infection. Dolphins with ingested gear or severe entanglements may swim away with the gear, but likely die later. Propeller injuries involving only soft tissue were often survivable. Some dolphins survived amputations of the distal ends of fins, and continued to reproduce. As a precautionary approach, dolphins with ingested gear or severe constrictive entanglements should be considered mortalities, but extrapolations of findings from coastal bottlenose dolphins to other cetaceans and different gear must be done with caution.     

The effects of formalin and isopropyl alcohol on length and weight measurements of Sarotherodon mossambicus Trewavas

Two groups of 30 Sarotherodon mossambicus were weighed and measured when alive, after 5 days in 10% formalin, and after 5, 10, 15, 20, 25, 30 and 65 days in 37.5% isopropyl alcohol. Fish from two size classes were preserved and all fish initially increased slightly in length and increased greatly in weight. The greatest increases in length and weight were noted after 5 days in formalin solution. After 65 days in isopropyl alcohol, the length of the preserved fish decreased to approach the live length while the weight of the fish stabilized at a higher than live weight value. This study is the first report of slight length increases or no shrinkage in preserved fish. Comments on the use of standard correction factors for lengthweight studies of preserved fish are provided.     

Neolithic urban primacy: The case against the invention of agriculture

It is proposed that sowing seed preceded agriculture by many millenia and that the invention of sowing is independent of the Neolithic Revolution. The advantages of using permanent seed stores as the source of seed grain is much more difficult to perceive and it is upon this accident that full-scale agriculture waited. Jacobs' (1969) model of cities before agriculture is the explanation of permanent seed bins for purely economic reasons. It is the role of bin permanence in switching the selective mechanism towards cultivars that explains the precipitous events c. 8000 B.C. Once cultivars are developed, true large-scale agriculture becomes an obvious advantage but not until the cultivars are there. Jacobs' model seeks to put hunters and traders into a positive loop that alone produces the city. This could not be so for there is not enough food at appropriate points in the model; but if casual sowing can be invoked as a long-standing precursor, then the extra forcing function allows the vital transition to genetic continuity in the harvested grain.     

Temporal expression of myogenic regulatory genes during activation,proliferation, and differentiation of rat skeletal muscle satellite cells

The satellite cell is responsible for growth and repair of postnatal skeletal muscle. We investigated the expression of the myogenic regulatory gene (MRG) family in these cells in the stages from quiescence to fusion. Using polymerase chain reaction amplification of reverse-transcribed RNA (RT-PCR) isolated from adult rat satellite cells, we demonstrated a temporal sequence of gene activation, which is distinct from that previously observed in embryonic somitic cells. No MRG expression was detected in predominantly quiescent cells. MyoD is activated by 12 h in cell culture, prior to the first evidence of proliferation. MRF4 and myf-5 appear by 48 h and may be associated with the first division cycle. Myogenin is not detectable until 72 h after satellite cell recovery from the muscle fiber, coincidental with the first evidence of differentiation. © 1994 wiley-Liss, Inc.     

Impact of the direct application of therapeutic agents to the terminal recta of experimentally colonized calves on Escherichia coli O157:H7 shedding

Enterohemorrhagic Escherichia coli O157:H7 is an important intestinal pathogen of humans with a main reservoir of domesticated ruminants, particularly cattle. It is anticipated that the risk of human infection can be reduced by controlling the organism within its reservoir hosts. Several options for the control of E. coli O157:H7 in cattle have been proposed, but none have been demonstrated to be successful in the field. Here we describe a novel experimental method, based on the terminal-rectum-restricted colonization described previously, to eliminate fecal carriage of E. coli O157:H7. In experimentally challenged calves, direct application to the rectal mucosa of either of two therapeutic agents, polymyxin B or chlorhexidine, greatly reduced bacterial shedding levels in the immediate posttreatment period. The most efficacious therapeutic agent, chlorhexidine, was compared in orally and rectally challenged calves. The treatment eliminated high-level shedding and reduced low-level shedding by killing bacteria at the terminal rectum. A rapid-detection system based on the ability to identify E. coli O157:H7 from swabs of the rectal mucosa was also assessed. This test was sufficiently sensitive to identify high-level bacterial carriage. Thus, a combination of the detection method and treatment regimens could be used in the field to eliminate high-level fecal excretion of E. coli O157:H7, so greatly reducing its prevalence within this host and the risk of human infection.