The toxic effects of rubber contaminants on microbial food webs and zooplankton of two lakes of different trophic status

Rubber is commonly used in recreational equipment and devicesforsampling in lakes, but there have been few studies of theeffectsof rubber on planktonic organisms. We investigated the toxiceffects of rubber on the microbial food webs of a mesotrophiclakeand a eutrophic lake. Lake water was collected by pumping via,(i) a polyvinylchloride hose and, (ii) a rubber hose. Samplesoflake water collected by each method were incubated insitu in4.25 l enclosures for four days. The lake water was sampledbeforeand after incubation to determine the concentrations ofinorganicnutrients, chlorophyll a, microorganisms (bacteria,picophytoplankton, flagellates, ciliates) and zooplankton.In the mesotrophic lake, momentary exposure (ten seconds) oflakewater to the rubber hose significantly lowered theconcentrationsof chlorophyll a, bacteria, picophytoplankton and somespecies of zooplankton (Boeckella hamata, Bosmina,androtifers), relative to those in water exposed to the plastichose;flagellates, ciliates and Ceriodaphnia dubia were notsignificantly affected. In the eutrophic lake, the effects oftherubber hose on components of the microbial food web were muchlesssevere, and were consistent with the lake's high levels ofdissolved organic carbon (DOC), which is known to chelatetoxicmetals in water.     

A novel fluorescence ratiometric method confirms the low solvent viscosity of the cytoplasm.

Two homologous indocyanine dyes, Cy3.18 and Cy5.18, can be used as a ratio pair for fluorometric determination of solvent viscosity. Succinimidyl ester derivatives of these dyes can be attached to inert carrier macromolecules, such as Ficoll 70, for measurement of intracellular or intravesicular solvent viscosity. When the viscosity of the solvent was varied by various methods, the fluorescence intensity ratio (Cy3/Cy5) in a mixture of Cy3.18-Ficoll 70 (Cy3F70) and Cy5.18-Ficoll 70 (Cy5F70) in solution was found to be solely a function of solvent viscosity and was insensitive to other solvent parameters such as dielectric constant, temperature, and the ability of the solvent to form hydrogen bonds. Most important, it was insensitive to the presence of large macromolecules, such as proteins, which increase the shear viscosity but have little effect on solvent viscosity. Following microinjection into the cytoplasm of living tissue culture cells, no binding of Cy3F70 or Cy5F70 to intracellular components was detected by fluorescence recovery after photobleaching. Fluorescence intensity ratio imaging of Cy3F70 and Cy5F70 in non-motile interphase CV1 and PtK1 cells showed that the solvent viscosity of cytoplasm was not significantly different from water and showed no spatial variation.     

Induction and suppression of immunoglobulin synthesis in cultures of human lymphocytes: effects of pokeweed mitogen and Staphylococcus aureus Cowan I

The synthesis and secretion of immunoglobulins by human peripheral blood mononuclear cells in cultures stimulated with pokeweed mitogen or Staphylococcus aureus Cowan I were evaluated by enumeration of cells containing cytoplasmic immunoglobulins and cells actively secreting immunoglobulins, and by quantitation of immunoglobulins released into culture supernatants. The two mitogens caused comparable stimulation of immunoglobulin production; however, in contrast to pokeweed mitogen, S. aureus was active in cultures depleted of T lymphocytes, and its stimulatory effects were resistant to the influence of suppressor T cells generated by co-stimulation with concanavalin A or by preincubation without mitogenic stimulus. These results indicate distinct pathways of induction and suppression of immunoglobulin synthesis for these two polyclonal B cell activators, and suggest that stimulation by S. aureus is less thymus dependent than that induced by pokeweed mitogen.     

Prenatal determination of obesity, tumor susceptibility, and coat color pattern in viable yellow (Avy/a) mice. The yellow mouse syndrome

Maturity-onset obesity and elevated circulating insulin levels are characteristic of some, but not all, mice bearing the viable yellow mutation (Avy) at the agouti locus. The expression of the Avy/a genotype in individual mice, which become obese and which remain lean is determined during prenatal development by as yet unidentified conditions in the dam's reproductive tract. One Avy/a phenotype is identified by a mottled yellow coat and characterized by adult obesity, elevated circulating insulin levels, and impaired glucose tolerance. These mice are notably more susceptible to hyperplasia and neoplasia. The alternative Avy/ a phenotype has a pseudoagouti coat, remains lean, is normoinsulinemic and normoglycemic, and in numerous other characteristics resembles congeneic lean black (a/a) littermates. Obese mottled yellow and lean pseudoagouti Avy/a mice differ in capacity to support the growth of ascites cells, in the growth response to castration, and in hepatic glutathione S-transferase activity, erythrocyte fragility, immune function, and susceptibility to Plasmodium yoelii pathogenesis. Our working hypothesis is that the constellation of characteristics, except coat color pattern, which differentiate the obese yellow mice from their lean littermates, is largely a consequence of the elevated circulating insulin levels that induce increased lipogenesis and decreased lipolysis, increased DNA and protein synthesis, increased mitosis in sensitive tissues, and increased proliferation of transformed cells.     

Misdiagnosis and delayed diagnosis in traumatic intracranial haematoma.

Out of 51 patients with traumatic intracranial haematoma admitted to a teaching hospital 11 (22%) died undiagnosed, and out of 307 such patients transferred to the West of Scotland Regional Neurosurgical Centre 111 (36%) had been deteriorating for more than 12 hours in another hospital. In two-thirds of these cases the delay was due to an erroneous diagnosis, either of cerebrovascular accident or of alcoholic intoxication.     

Studies on Papanicolaou Staining. III. Quantitative Investigations of Orangeophilia and Cyanophilia

This paper provides data derived from the visible light absorbance spectra of Papanicolaou stained epithelial cells from the uterine cervix. Twenty-four types of spectra have been considered, namely, those derived from orangeophilic and cyanophilic nuclei and cytoplasms of superficial, intermediate, parabasal and dysplastic cells, and cells of carcinoma in situ and invasive carcinoma. Wavelengths of maximum absorbance and peak absorbances are tabulated. The proportions of bound orange G, eosin Y, aluminum-hematein and light green SF yellowish have been calculated. For the majority of cell types, dyebinding differences between orangeophilic and corresponding cyanophilic substrates were statistically significant. CIE coordinates were calculated from absorbance spectra; again differences between orangeophilic and cyanophilic cells were statistically significant in most cases. Although the designation of cells as orangeophilic or cyanophilic is made on the basis of cytoplasmic coloration, the nucleus is also usually orangeophilic or cyanophilic. These nuclear differences are real and not due to the effects of over- and underlying cytoplasm.     

Alarm responses are maintained during captive rearing in chicks of endangered kaki

The maintenance of species-specific behavioural repertoires and traditions is an important but often implicit goal of conservation efforts. When captive rearing is used as a conservation practice, it becomes critical to address its possible implications for the social and behavioural traits of developing individuals. In particular, animals must retain or acquire many of their behavioural abilities to increase the likelihood of survival upon release into the wild. This study investigated the behavioural development of critically endangered kaki (black stilt: Himantopus novaezelandiae ) chicks reared without live adult conspecifics. The captive rearing programme included playbacks of adult kaki alarm calls during cleaning and handling of precocial chicks housed as groups. We used videotaped observations and playback experiments to address the following questions: do kaki chicks respond differentially to (1) familiar versus unfamiliar adult kaki alarm calls and (2) conspecific alarm versus heterospecific control vocalizations. Adult-naïve kaki chicks exhibited a varied behavioural repertoire over their early development. In multivariate analyses, when age was statistically controlled, chicks showed responses to familiar and unfamiliar alarm calls that were similar in magnitude. In contrast, following conspecific alarm calls chicks had longer average latencies to resume pre-playback activities than following heterospecific vocalizations. Although the generality of these conclusions is limited by experimental constraints stemming from working with an endangered species, the findings suggest that current management techniques produce captive-reared kaki for release into the wild that possess many of the behavioural and auditory recognition skills that are required for survival.     

Donor life stage influences juvenile American eel Anguilla rostrata attraction to conspecific chemical cues

The present study investigated the potential role of conspecific chemical cues in inland juvenile American eel Anguilla rostrata migrations by assessing glass eel and 1 year old elver affinities to elver washings, and elver affinity to adult yellow eel washings. In two‐choice maze assays, glass eels were attracted to elver washings, but elvers were neither attracted to nor repulsed by multiple concentrations of elver washings or to yellow eel washings. These results suggest that A. rostrata responses to chemical cues may be life‐stage dependent and that glass eels moving inland may use the odour of the previous year class as information to guide migration. The role of chemical cues and olfaction in eel migrations warrants further investigation as a potential restoration tool.