Mink on the brink: comparing survey methods for detecting a critically endangered carnivore, the European mink Mustela lutreola

Monitoring rare and elusive species is critical in guiding appropriate conservation management measures. Mammalian carnivores are challenging to monitor directly, due to their generally nocturnal and solitary lifestyle, and relatively large home ranges. The European mink Mustela lutreola is a critically endangered, small, semi-aquatic carnivore and is one of the most threatened mammal species in Europe. In northern Spain, the European mink population is monitored regionally using different methods and approaches, making assessment of national population status difficult. There is an urgent need to 1) assess the efficacy of survey methods and 2) identify a standard monitoring methodology that can be deployed rapidly and inexpensively over large areas of the mink’s range. We deployed four methods—camera trapping, hair tubes, live trapping, and environmental DNA (eDNA) from water samples—to compare the probability of detecting European mink when present at 25 sampling sites within five 10 × 10 km2, and the economic cost and time required for each method. All four methods successfully detected European mink but the probability of detection varied by method. Camera trapping and hair tubes had the highest probability of detection; however, eDNA and live trapping detected mink in one 10 × 10 km2 where the latter two methods did not. For future European mink monitoring programs, we recommend a combination of at least two methods and suggest that camera traps or hair tubes are combined with live trapping or eDNA (depending on the scale and aims of the study), to gather critical information on distribution, occupancy and conservation status.

Social feasibility assessments in conservation translocations

Improving the effectiveness of conservation translocations could contribute to reversing global biodiversity loss. Although evaluations of ecological factors affecting translocation outcomes are commonplace, consideration of human social factors remains rare, hindering improvements to this conservation practice. We analysed 550 translocation case studies to explore the inclusion of social factors in project feasibility assessments. Reviewed projects often failed to assess social feasibility, and assessments, where attempted, tended to be narrow in scope. Consequently, challenges such as proactively addressing conflict often remained unaddressed. Insufficient knowledge sharing and prioritisation of ecological feasibility, to the detriment of social feasibility, remain barriers to effective planning. Successful outcomes of translocations are linked to early assessment of social feasibility and to the establishment of long-term commitments between people, places, and partners.

Dawn and dusk peaks of outer segment phagocytosis, and visual cycle function require Rab28

RAB28 is a farnesylated, ciliary G-protein. Patient variants in RAB28 are causative of autosomal recessive cone-rod dystrophy (CRD), an inherited human blindness. In rodent and zebrafish models, the absence of Rab28 results in diminished dawn, photoreceptor, outer segment phagocytosis (OSP). Here, we demonstrate that Rab28 is also required for dusk peaks of OSP, but not for basal OSP levels. This study further elucidated the molecular mechanisms by which Rab28 controls OSP and inherited blindness. Proteomic profiling identified factors whose expression in the eye or whose expression at dawn and dusk peaks of OSP is dysregulated by loss of Rab28. Notably, transgenic overexpression of Rab28, solely in zebrafish cones, rescues the OSP defect in rab28 KO fish, suggesting rab28 gene replacement in cone photoreceptors is sufficient to regulate Rab28-OSP. Rab28 loss also perturbs function of the visual cycle as retinoid levels of 11-cRAL, 11cRP, and atRP are significantly reduced in larval and adult rab28 KO retinae (p < .05). These data give further understanding on the molecular mechanisms of RAB28-associated CRD, highlighting roles of Rab28 in both peaks of OSP, in vitamin A metabolism and in retinoid recycling.

Genetic Deletion of Zebrafish Rab28 Causes Defective Outer Segment Shedding, but Not Retinal Degeneration

The photoreceptor outer segment is the canonical example of a modified and highly specialized cilium, with an expanded membrane surface area in the form of disks or lamellae for efficient light detection. Many ciliary proteins are essential for normal photoreceptor function and cilium dysfunction often results in retinal degeneration leading to impaired vision. Herein, we investigate the function and localization of the ciliary G-protein RAB28 in zebrafish cone photoreceptors. CRISPR-Cas9 generated rab28 mutant zebrafish display significantly reduced shed outer segment material/phagosomes in the RPE at 1 month post fertilization (mpf), but otherwise normal visual function up to 21 dpf and retinal structure up to 12 mpf. Cone photoreceptor-specific transgenic reporter lines show Rab28 localizes almost exclusively to outer segments, independently of GTP/GDP nucleotide binding. Co-immunoprecipitation analysis demonstrates tagged Rab28 interacts with components of the phototransduction cascade, including opsins, phosphodiesterase 6C and guanylate cyclase 2D. Our data shed light on RAB28 function in cones and provide a model for RAB28-associated cone-rod dystrophy.

Ciliary Rab28 and the BBSome negatively regulate extracellular vesicle shedding

Cilia both receive and send information, the latter in the form of extracellular vesicles (EVs). EVs are nano-communication devices that influence cell, tissue, and organism behavior. Mechanisms driving ciliary EV biogenesis are almost entirely unknown. Here, we show that the ciliary G-protein Rab28, associated with human autosomal recessive cone-rod dystrophy, negatively regulates EV levels in the sensory organs of Caenorhabditis elegans in a cilia specific manner. Sequential targeting of lipidated Rab28 to periciliary and ciliary membranes is highly dependent on the BBSome and the prenyl-binding protein phosphodiesterase 6 subunit delta (PDE6D), respectively, and BBSome loss causes excessive and ectopic EV production. We also find that EV defective mutants display abnormalities in sensory compartment morphogenesis. Together, these findings reveal that Rab28 and the BBSome are key in vivo regulators of EV production at the periciliary membrane and suggest that EVs may mediate signaling between cilia and glia to shape sensory organ compartments. Our data also suggest that defects in the biogenesis of cilia-related EVs may contribute to human ciliopathies.

Membrane retrieval, recycling and release pathways that organise and sculpt the ciliary membrane

The microtubule-based cilium that extends from the surface of most eukaryotic cell types serves motility, sensory reception and cell-cell signaling functions, and is disrupted in wide-ranging ciliopathy disorders. The cilium is heavily reliant on dynamic and tuneable intracellular trafficking systems such as intraflagellar transport and Golgi-derived secretory pathways, which control the organelle's structure, function and molecular composition. More recently, endosomal retrieval and recycling, as well as extracellular vesicle (EV) release, pathways have been associated with ciliary membrane control. Here, we discuss the emerging role of these pathways in the control of ciliary membrane homeostasis. The new findings provide a deeper and more integrated understanding of how the ciliary membrane is organised.

Bait uptake by wild badgers and its implications for oral vaccination against tuberculosis

The deployment of baits containing vaccines or toxins has been used successfully in the management of wildlife populations, including for disease control. Optimisation of deployment strategies seeks to maximise uptake by the targeted population whilst ensuring cost-effectiveness. Tuberculosis (TB) caused by infection with Mycobacterium bovis affects a broad range of mammalian hosts across the globe, including cattle, wildlife and humans. The control of TB in cattle in the UK and Republic of Ireland is hampered by persistent infection in European badgers (Meles meles). The present study aimed to determine the best strategy for maximising uptake of an oral vaccine by wild badgers, using a surrogate novel bait deployed at 40 badger social groups. Baits contained a blood-borne biomarker (Iophenoxic Acid, IPA) in order to measure consumption in badgers subsequently cage trapped at targeted setts. Evidence for the consumption of bait was found in 83% (199/240) of captured badgers. The probability that badgers had consumed at least one bait (IPA >10 μg ml-1) was significantly higher following deployment in spring than in summer. Lower uptake amongst social groups where more badgers were captured, suggested competition for baits. The probability of bait consumption was significantly higher at groups where main and outlier setts were provided with baits than at those where outliers were present but not baited. Badgers captured 10-14 days post bait feeding had significantly higher levels of bait uptake compared to those caught 24-28 days later. Uptake rates did not vary significantly in relation to badger age and whether bait was placed above ground or down setts. This study suggests that high levels of bait uptake can be achieved in wild badger populations and identifies factors influencing the potential success of different deployment strategies. The implications for the development of an oral badger vaccine are discussed.

Distraction during Deployment: Marital Relationship Associations with Spillover for Deployed Army Soldiers

Military spouses often have concerns regarding the impact of their communication on soldiers during deployment. However, literature is mixed regarding how communication between soldiers and spouses may impact soldiers' self-reported work functioning during deployment, suggesting the need to evaluate moderating factors. In the current study, three relationship factors (marital satisfaction, conflictual communication, and proportion of conversation focused on problems) were tested as moderators of communication frequency and negative marriage-to-work spillover for soldiers. Whereas the three relationship factors were independently related to negative spillover, none significantly moderated the relationship between communication frequency and spillover. The overall pattern of results suggests that (a) lower marital satisfaction, a focus on problems during communication, and conflictual communication are each strongly linked to spillover for deployed soldiers, and (b) military couples may be self-restricting deployment communication frequency when experiencing less marital satisfaction and higher rates of negative communication. Implications for communication during deployment are discussed.

Testing of a palatable bait and compatible vaccine carrier for the oral vaccination of European badgers (Meles meles) against tuberculosis

The oral vaccination of wild badgers (Meles meles) with live Bacillus Calmette-Guérin (BCG) is one of the tools being considered for the control of bovine tuberculosis (caused by Mycobacterium bovis) in the UK. The design of a product for oral vaccination requires that numerous, and often competing, conditions are met. These include the need for a highly palatable, but physically stable bait that will meet regulatory requirements, and one which is also compatible with the vaccine formulation; in this case live BCG. In collaboration with two commercial bait companies we have developed a highly attractive and palatable bait recipe designed specifically for European badgers (Meles meles) that meets these requirements. The palatability of different batches of bait was evaluated against a standardised palatable control bait using captive badgers. The physical properties of the bait are described e.g. firmness and colour. The microbial load in the bait was assessed against European and US Pharmacopoeias. The bait was combined with an edible vaccine carrier made of hydrogenated peanut oil in which BCG vaccine was stable during bait manufacture and cold storage, demonstrating <0.5 log₁₀ reduction in titre after 117weeks' storage at -20°C. BCG stability in bait was also evaluated at +4°C and under simulated environmental conditions (20°C, 98% Relative Humidity; RH). Finally, iophenoxic acid biomarkers were utilised as a surrogate for the BCG vaccine, to test variants of the vaccine-bait design for their ability to deliver biomarker to the gastrointestinal tract of individual animals. These data provide the first detailed description of a bait-vaccine delivery system developed specifically for the oral vaccination of badgers against Mycobacterium bovis using live BCG.

Behaviour of European badgers and non-target species towards candidate baits for oral delivery of a tuberculosis vaccine

In the UK and the Republic of Ireland, the European badger (Meles meles) is a maintenance host for Mycobacterium bovis, and may transmit the infection to cattle causing bovine tuberculosis (TB). Vaccination of badgers using an injectable Bacillus Calmette-Guerin (BCG) vaccine is undertaken in some areas of the UK with the intention of interrupting this transmission, and vaccination research is underway in Ireland. An oral badger TB vaccine is also under development. We investigated the behaviour of badgers and non-target wildlife species towards three candidate baits being considered for delivering BCG to badgers orally. Bait preference was investigated by recording removal rates of baits and through the use of video surveillance at 16 badger setts. We found high variation in rates of bait removal by badgers among setts but no significant differences in removal rates among bait types or in preference behaviour from video footage. Variation in bait removal among setts correlated with the number of nights on which badgers were seen at the sett, with most baits being removed where badgers were seen on >50% of nights during the ten-day study period. Relatively few baits were removed at setts with low levels of recorded badger activity. Monitoring badger activity prior to bait deployment may therefore be useful in increasing bait uptake and vaccine coverage. Bait removal by badgers increased over the ten-day study period, suggesting initial neophobic behaviour at some setts and that a period of 'pre-feeding' may be required prior to vaccine deployment. Our results indicate that all three candidate baits are attractive to badgers. Removal of baits by non-target wildlife species was generally low, but varied among bait types, with smaller baits in packaging less likely to be removed. Enclosing baits in packaging is likely to deter non-target species, although in some cases non-target species did remove up to 13% of packaged baits.

Peer Counseling or Peer Support—There is a Difference

The purpose of this study was to conduct a comprehensive evaluation of a peer helping program in a high school setting. Opinions were obtained from students, staff, peer support members, their parents, and their “clients.” A large sample was obtained for the general student survey (204 students, or 73% of the student population). The results validated the basic assumptions on which peer helping programs are founded, namely, that students most often seek out other students for help with problems and that students are thought to be capable of providing help for their peers. The results indicate that although students have confidence in one another for helping, few students said they would seek help with a problem from a peer counselor. It is thought that existing peer counseling programs are perhaps too small to adequately represent all peer groups within the school and that attempts should be made to expand membership in the program in order to reach more students. It was also indicated that students have greater confidence in a peer's ability for helping with school and relationship problems, whereas less confidence was shown for dealing with problems of a more serious nature such as suicide, death, and pregnancy. This point emphasizes the difference between peer counseling and “professional” counseling programs. It is proposed that for peer helping programs to grow the distinction between support and counseling become clear in the minds of those running the program and that alternate methods for program selection and training need to be explored.

Vaccination against tuberculosis in badgers and cattle: an overview of the challenges, developments and current research priorities in Great Britain

Bovine tuberculosis (TB) is a significant threat to the cattle industry in England and Wales. It is widely acknowledged that a combination of measures targeting both cattle and wildlife will be required to eradicate bovine TB or reduce its prevalence until European official freedom status is achieved. Vaccination of cattle and/or badgers could contribute to bovine TB control in Great Britain, although there are significant gaps in our knowledge regarding the impact that vaccination would actually have on bovine TB incidence. Laboratory studies have demonstrated that vaccination with BCG can reduce the progression and severity of TB in both badgers and cattle. This is encouraging in terms of the prospect of a sustained vaccination programme achieving reductions in disease prevalence; however, developing vaccines for tackling the problem of bovine TB is challenging, time-consuming and resource-intensive, as this review article sets out to explain.

Denning behaviour of the European badger (Meles meles) correlates with bovine tuberculosis infection status

Heterogeneities in behaviours of individuals may underpin important processes in evolutionary biology and ecology, including the spread of disease. Modelling approaches can sometimes fail to predict disease spread, which may partly be due to the number of unknown sources of variation in host behaviour. The European badger is a wildlife reservoir for bovine tuberculosis (bTB) in Britain and Ireland, and individual behaviour has been demonstrated to be an important factor in the spread of bTB among badgers and to cattle. Radio-telemetry devices were deployed on 40 badgers from eight groups to investigate patterns of den (sett) use in a high-density population, where each group had one or two main and three to eight outlier setts in their territory. Badgers were located at their setts for 28 days per season for 1 year to investigate how patterns differed between individuals. Denning behaviour may have a strong influence on contact patterns and the transmission of disease. We found significant heterogeneity, influenced by season, sex and age. Also, when controlling for these, bTB infection status interacting with season was highly correlated with sett use. Test-positive badgers spent more time away from their main sett than those that tested negative. We speculate that wider-ranging behaviour of test-positive animals may result in them contacting sources of infection more frequently and/or that their behaviour may be influenced by their disease status. Measures to control infectious diseases might be improved by targeting functional groups, specific areas or times of year that may contribute disproportionately to disease spread.

BCG vaccination reduces risk of tuberculosis infection in vaccinated badgers and unvaccinated badger cubs

Wildlife is a global source of endemic and emerging infectious diseases. The control of tuberculosis (TB) in cattle in Britain and Ireland is hindered by persistent infection in wild badgers (Meles meles). Vaccination with Bacillus Calmette-Guérin (BCG) has been shown to reduce the severity and progression of experimentally induced TB in captive badgers. Analysis of data from a four-year clinical field study, conducted at the social group level, suggested a similar, direct protective effect of BCG in a wild badger population. Here we present new evidence from the same study identifying both a direct beneficial effect of vaccination in individual badgers and an indirect protective effect in unvaccinated cubs. We show that intramuscular injection of BCG reduced by 76% (Odds ratio = 0.24, 95% confidence interval (CI) 0.11-0.52) the risk of free-living vaccinated individuals testing positive to a diagnostic test combination to detect progressive infection. A more sensitive panel of tests for the detection of infection per se identified a reduction of 54% (Odds ratio = 0.46, 95% CI 0.26-0.88) in the risk of a positive result following vaccination. In addition, we show the risk of unvaccinated badger cubs, but not adults, testing positive to an even more sensitive panel of diagnostic tests decreased significantly as the proportion of vaccinated individuals in their social group increased (Odds ratio = 0.08, 95% CI 0.01-0.76; P = 0.03). When more than a third of their social group had been vaccinated, the risk to unvaccinated cubs was reduced by 79% (Odds ratio = 0.21, 95% CI 0.05-0.81; P = 0.02).

Performance of proximity loggers in recording intra- and inter-species interactions: a laboratory and field-based validation study

Knowledge of the way in which animals interact through social networks can help to address questions surrounding the ecological and evolutionary consequences of social organisation, and to understand and manage the spread of infectious diseases. Automated proximity loggers are increasingly being used to record interactions between animals, but the accuracy and reliability of the collected data remain largely un-assessed. Here we use laboratory and observational field data to assess the performance of these devices fitted to a herd of 32 beef cattle (Bos taurus) and nine groups of badgers (Meles meles, n  = 77) living in the surrounding woods. The distances at which loggers detected each other were found to decrease over time, potentially related to diminishing battery power that may be a function of temperature. Loggers were highly accurate in recording the identification of contacted conspecifics, but less reliable at determining contact duration. There was a tendency for extended interactions to be recorded as a series of shorter contacts. We show how data can be manipulated to correct this discrepancy and accurately reflect observed interaction patterns by combining records between any two loggers that occur within a 1 to 2 minute amalgamation window, and then removing any remaining 1 second records. We make universally applicable recommendations for the effective use of proximity loggers, to improve the validity of data arising from future studies.

Culling-induced social perturbation in Eurasian badgers Meles meles and the management of TB in cattle: an analysis of a critical problem in applied ecology

The Eurasian badger (Meles meles) is implicated in the transmission of bovine tuberculosis (TB) to cattle in the UK and Republic of Ireland. Badger culling has been employed for the control of TB in cattle in both countries, with varying results. Social perturbation of badger populations following culling has been proposed as an explanation for the failure of culling to consistently demonstrate significant reductions in cattle TB. Field studies indicate that culling badgers may result in increased immigration into culled areas, disruption of territoriality, increased ranging and mixing between social groups. Our analysis shows that some measures of sociality may remain significantly disrupted for up to 8 years after culling. This may have epidemiological consequences because previous research has shown that even in a relatively undisturbed badger population, movements between groups are associated with increases in the incidence of Mycobacterium bovis infection. This is consistent with the results from a large-scale field trial, which demonstrated decreased benefits of culling at the edges of culled areas, and an increase in herd breakdown rates in neighbouring cattle.

Study of lithium absorption by users of spas treated with lithium ion

This study examines the possible dermal absorption of lithium ion into the blood serum of spa/hot tub bathers. Fifty-three participants (28 males and 25 females) spent 20 minutes per day, 4 days per week for 2 consecutive weeks in one of two assigned spas. The participants were randomly assigned to one of the two spas after matching based on sex, age, and use of oral contraceptives. The test spa contained 40 +/- 5 ppm lithium ion, while the control spa contained no additional lithium ion above the background levels of approximately 0.02 ppm. The exposure in the spa treated with lithium ion (from lithium chloride) simulated the maximum exposure that would be expected in a spa sanitized with lithium hypochlorite. The two spas were maintained at 101 +/- 2 degrees F. Serum lithium ion levels before and after spa use were determined using graphite-furnace atomic absorption spectroscopy with a minimum detectable level of lithium ion in serum of 2 micrograms l-1 (ppb). There was no statistically significant difference in serum lithium levels between the control and treatment group at any stage. We conclude that dermal exposure to lithium ion (as would be present after treatment of a spa with lithium hypochlorite) did not result in a detectable increase in the serum lithium ion level.

Effect of derivatives of chrysophanol, a new type of potential antitumor agents of anthraquinone family, on growth and cell cycle of L1210 leukemic cells

The new C-methyl modified derivatives of the anthraquinones chrysophanol and emodin, recently synthesized by us, are potentially bifunctional agents having the ability to intercalate to nucleic acids and also having alkylating properties. Two of these compounds, namely 3-(N,N-bis(2-chloroethyl)-amino)methyl-1,8-dihydroxy-9,10-anthraquinone (Compound 31.662) and its 1,8-di-O-methylated analog (Compound 31.655) have been presently tested on murine leukemic L1210 cells in vitro with respect to their cell cycle specificity. During the initial 24 h of treatment the cytostatic effects of the drugs predominated, manifesting as suppression of cell progression through S (especially through the early portion of S phase) and G2. After 24 h, the cytotoxic effects became apparent, and there was also the appearance of cells with doubled DNA content suggestive of either endoreduplication or impairment of cytokinesis; these cells at higher ploidy level were progressing through S and G2. The observed effects were time- and dose-dependent, occurring at 0.1-0.4 micrograms/ml concentration of 31.662 and 2.0-10.0 micrograms/ml of its methylated analog, either during continuous- or after a 4-h pulse-treatment. Modulation of the cell cycle by the studied drugs is similar to that generally caused by intercalators as well as alkylating agents. However, because no positive evidence of intercalation of the studied drugs to nucleic acids was found, it is possible that alkylation of DNA or other cell constituents may be the primary lesion(s) leading to perturbation of the cell cycle.

Thermal stability of nucleosomes studied in situ by flow cytometry: effect of ionic strength and n-butyrate

Heating of cells permeabilized with ethanol and resuspended in aqueous media increases accessibility of DNA to intercalating dyes such as acridine orange (AO). The curves, representing increase in binding of AO as a function of rise in temperature, indicate that the transitions are cooperative. The transitions are sensitive to ionic strength and occur at lower temperatures when cells are suspended in media of increasing ionic strength. Extraction of histones raises accessibility of DNA to intercalators at room temperature, and heating has little effect on additional binding. The results are interpreted as indicating thermal destruction of nucleosomal structure in nuclear chromatin; dissociation of DNA from core histones results in its increasing ability to intercalate AO, most likely due to increased topological freedom to undergo unwinding and elongation following binding of the intercalator. Preincubation of cells with n-butyrate, known to induce histone hyperacetylation, lowers the heat stability of nucleosomes by about 5 degrees C. On the other hand, no differences are observed between chromatin of mitotic vs interphase cells tested over a wide range of ionic strengths (0.1-0.7 N NaCl). The method appears to be useful as a probe of chromatin structure at the nucleosomal level.

Cytostatic and cytotoxic effects of Pannon (P-30 Protein), a novel anticancer agent

P-30 Protein is a novel protein, of molecular weight approximately 15 KD, obtained from the extract of a vertebrate tissue showing in vivo antitumour activity. Cytostatic and cytotoxic effects of this product in its purified form (P-30 Protein) or in partially purified extracts (Pannon) were studied in vitro on human leukaemic HL-60, human submaxillary carcinoma A-253, human colon adenocarcinoma Colo 320 CM and murine erythroleukaemia (Friend leukaemia) cell lines. Of these cells, HL-60, A-253 and Colo 320 CM were sensitive and Friend leukaemia resistant to this agent. The effects were time- and concentration-dependent. During the initial 24-48 h of treatment, a slowdown in cell proliferation was apparent but cell death was not extensive. After 24-48 h, there was a reduction in the proportion of cells in S phase of the cell cycle and the cells became preferentially arrested in G1 phase. The G1 cells showed high heterogeneity with respect to RNA content and some cells were characterized by very low RNA content. Progressive cell death occurred in cultures maintained with Pannon for up to 7 d in proportion to its concentration. Reductions of 50 and 90% in clonogenicity of A-253 cells were observed during their growth in the presence of 0.13 and 1.5 micrograms/ml of this protein, respectively. Exponentially growing cells were more sensitive to Pannon compared with cells from confluent cultures. Colonies of A-253 cells growing in the presence of Pannon were much smaller in size compared with control colonies, indicating that the rate of proliferation of clonogens is reduced by this agent. It appears that P-30 Protein induces cytostatic effects via modulation of cell transition to quiescence or differentiation. The mechanism of its cytotoxic activity is unclear.

Photosensitizing effects of the tricyclic heteroaromatic cationic dyes pyronin Y and toluidine blue O (tolonium chloride)

Pyronin Y [3,6-bis(dimethylamino)xanthylium chloride; PY] and toluidine blue O [tolonium chloride; 3-amino-7-(dimethylamino)-2-methyl phenothiazin-5-ium chloride; TB] are cationic dyes commonly used in cytochemistry that have affinity to nucleic acids, predominantly to RNA. In live cells these dyes accumulate in mitochondria and sensitize the cells to light. The photosensitizing effects of PY and TB were compared with those of another mitochondrial cationic dye, rhodamine 123, and a noncationic dye, merocyanine 540, which binds to the cell membrane. Ninety % reduction of clonogenicity of human epidermoid carcinoma (A-253) cells pretreated with 3.3 microM PY, 0.67 microM TB, 13 microM rhodamine 123, or 18 microM merocyanine 540 was achieved by cell exposure to 0.7, 1.0, 1.2, or 1.5 J/cm2 doses of white light, respectively. The above concentrations of PY, TB, or merocyanine 540 represent the maximal ones at which the effect of each of these dyes alone, in the dark, in reducing cell clonogenicity was less than 12%. Exposure of A-253 cells to light at doses reducing clonogenicity by 50% caused a transient (24 h) arrest of the surviving cell population in the G1 phase of the cell cycle. In contrast to A-253 cells, Chinese hamster ovary cells were highly resistant to the photosensitizing effects of each of the four dyes. Also, the normal human lung fibroblasts (WI-38) were highly resistant to photosensitization by PY, whereas the simian virus 40-transformed WI-38 cells and another carcinoma line (OV-3) were sensitive. The data suggest that PY and TB, like other mitochondrial dyes, may have a selective antitumor photosensitizing activity.

In situ factors affecting stability of the DNA helix in interphase nuclei and metaphase chromosomes

The data from earlier cytochemical studies, in which the metachromatic fluorochrome acridine orange (AO) was used to differentially stain single vs double-stranded DNA, suggested that DNA in situ in intact metaphase chromosomes or in condensed chromatin of G0 cells is more sensitive to denaturation, induced by heat or acid, than DNA in decondensed chromatin of interphase nuclei. Present studies show that, indeed, DNA in permeabilized metaphase cells, in contrast to cells in interphase, when exposed to buffers of low pH (1.5-2.8) becomes digestible with the single-strand-specific S1 or mung bean nucleases. A variety of extraction procedures and enzymatic treatments provided evidence that the presence of histones, HMG proteins, and S-S bonds in chromatin, as well as phosphorylation or poly(ADP)ribosylation of chromatin proteins, can be excluded as a factor responsible for the differential sensitivity of metaphase vs interphase DNA to denaturation. Cell treatment with NaCl at a concentration of 1.2 N and above abolished the difference between interphase and mitotic cells, rendering DNA in mitotic cells less sensitive to denaturation; such treatment also resulted in decondensation of chromatin visible by microscopy. The present data indicate that structural proteins extractable with greater than or equal to 1.2 N NaCl may be involved in anchoring DNA to the nuclear matrix or chromosome scaffold and may be responsible for maintaining a high degree of chromatin compaction in situ, such as that observed in metaphase chromosomes or in G0 cells. Following dissociation of histones, the high spatial density of the charged DNA polymer may induce topological strain on the double helix, thus decreasing its local stability; this can be detected by metachromatic staining of DNA with AO or digestion with single-strand-specific nucleases.

Effect of recombinant tumor necrosis factor on HL-60 cells: cell-cycle specificity and synergism with actinomycin D

The tumor necrosis factor (TNF) exhibits a multitude of activities depending on the type of target cells. We characterized the cytostatic and cytotoxic effects of recombinant TNF, alone and in combination with actinomycin D (AMD), on the human leukemic cell line HL-60. Because HL-60 cells, when triggered to monocytic differentiation by phorbol esters, are known to produce and secrete TNF, their sensitivity to the factor could indicate an autocrine function of TNF in this cell system. Indeed, HL-60 cells were affected by TNF; their doubling time was increased by about 50% and progression through the cell cycle was perturbed. Initially, (up to 8 h) TNF induced a temporary arrest in G2 while later (24-48 h) it delayed progression through the G1 phase. Also, a transient increase in RNA content peaking at 6-8 h was apparent. The cytotoxicity of TNF alone was low. Thus, TNF may be involved in the regulation of the cell cycle of HL-60 cells during early stages of their differentiation. The cytotoxicity of TNF was markedly potentiated in the presence of AMD; the effect was AMD but not TNF concentration-dependent. Whereas at 20 and 50 ng/ml of AMD alone nonviable cells did not exceed 20% during the first 24 h of treatment, their proportion increased to 80 and 90%, respectively, in the presence of TNF. The most sensitive were cells in the S phase of the cell cycle. The observed synergistic effect of TNF and AMD does not appear to be caused by the action of TNF increasing the permeability of the cell membrane to AMD. The results indicate that HL-60 cells, ordinarily resistant to the cytotoxic action of TNF, can be rendered sensitive by treatment with AMD. This implies that a combination of TNF and AMD may be considered in oncology for treatment of tumors otherwise nonresponding to TNF alone.

Cytostatic and cytotoxic properties of pyronin Y: relation to mitochondrial localization of the dye and its interaction with RNA

Pyronin Y (PY) is an intercalating cationic dye that shows specificity towards RNA. In viable cells this dye also accumulates in mitochondria. The cytostatic and cytotoxic effects of PY on L1210 and Chinese hamster ovary cells were studied in relation to its intracellular localization and compared with the affinity of PY to bind to double-stranded DNA and RNA and its propensity to condense single-stranded DNA and RNA. Antitumor properties of PY were tested on L1210 leukemia and Sarcoma 180 ascites in mice. At a concentration of 1.7 to 3.3 microM, PY was localized almost exclusively in mitochondria of cultured cells, similar to another mitochondrial probe, rhodamine 123. At that concentration PY was not toxic but suppressed cell growth, arresting cells in G1. At a concentration of 6.7 to 33.0 microM, PY was also localized in nucleoli and uniformly in cytoplasm, bound to the RNase-sensitive material therein. At that high concentration PY induced cell arrest in G2 and S and was cytotoxic. The dye exhibited a propensity to bind and condense (precipitate) single-stranded nucleic acids, and condensation could be measured by the appearance of light-scattering products. Among a variety of natural and synthetic nucleic acids the most sensitive were the RNA polymer, polyriboadenylate, and the copolymer, polyriboadenylate and polyriboguanylate, which underwent condensation at a PY concentration of 6.6 to 10.0 microM. Natural and synthetic DNA polymers were resistant to condensation. The data suggest that the cytostatic (G2 and S arrest) and cytotoxic (inability to exclude trypan blue, loss of clonogenicity) effects of PY seen at 6.7 to 33.0 microM concentration may be a consequence of the dye binding to RNA. PY may intercalate to double-stranded RNA and/or cause the specific condensation of single-stranded RNA; the polyadenylated sections of mRNA appear to be the most sensitive cellular targets to undergo condensation. PY showed antitumor properties extending survival of L1210 leukemic mice by 50% and slowing growth of Sarcoma 180 ascites tumor. The possibility that certain antitumor drugs, generally believed to act via intercalation to DNA, may exert chemotherapeutic effects via their interactions with RNA is discussed.

Interim report on the structures at Howe, Stromness, Orkney

Summary

Excavations at Howe revealed a complex series of settlements which spanned the whole of the Iron Age period and were preceded by two phases of Neolithic activity. A probable stalled cairn was succeeded by a Maes Howe type chambered tomb which was later followed by enclosed settlements of which only scant remains survived. These settlements were replaced by a roundhouse with earth-house, built into the ruins of the chambered tomb. The roundhouse was surrounded by a contemporary defended settlement. Rebuilding led to the development of a broch structure and village. Partial collapse of tower brought about changes in the settlement, andalthougk some houses were maintained as domestic structures, others were rebuilt as iron-working sheds. The construction of smaller buildings and a later Iron Age or Pictish extended farmstead into rubble collapse accompanied a decline in the size of the settlement. The abandonment of the farmstead marked the end of Howe as a settlement site.

Ganglioside profiles of metastases and of metastasizing and nonmetastasizing rat primary mammary carcinomas

The possible relationship between ganglioside levels and ganglioside profiles in malignant tumors and the formation of metastasis was investigated by the analysis of gangliosides in metastasizing SMT-2A and nonmetastasizing MT-W9a mammary carcinomas as well as in metastases formed from SMT-2A tumors. The extracted lipid of SMT-2A tumors contained 3.3-fold more lipid-bound sialic acid than did that of MT-W9a tumors. THe differences were also substantial in the ganglioside profiles in these 2 tumors. Plasma membranes isolated from SMT-2A tumors also contained 1.8-fold more lipid-bound sialic acid than did plasma membranes from MT-W9a tumors. Ganglioside profiles in two types of SMT-2A secondary tumors were investigated. The lipid-bound sialic acid content was 1.5-fold higher in tumor nodules in the lung and 1.9-fold higher in axillary lymph node tumors than it was in primary SMT-2A tumors. The ganglioside pattern in these 2 secondary tumors generally reflected that found in SMT-2A: high levels of gangliosides containing three or four sialic acid molecules. The lung nodule retained its specificity with respect to lipid-bound sialic acid content and ganglioside pattern after the lung nodule was sequentially transplanted three times to the site of the original SMT-2A tumor growth.