Histological health indices : linking complex pollutant exposure with tissue alteration in sand flathead Platycephalus bassensis

Port Phillip Bay, Victoria, is a pollutant-impacted environment that is extensively fished both professionally and recreationally. Consumption of contaminated fish represents a potential threat to human health, and fish exposed to environmental contaminants may themselves be affected in a similar fashion. This study describes a fish health index based on histological alterations identified in multiple organs of the sand flathead Platycephalus bassensis. Alterations were evident in tissues from all individuals assessed, with common pathologies observed in the gills, skin, kidney, liver and spleen. Alterations commonly present included necrosis, melanomacrophage centres, inflammation and multiple alterations of the gill epithelium (e.g. hyperplasia and hypertrophy). Fish health, calculated using severity of histological alterations, differed significantly across Port Phillip Bay, with heavily industrialized regions of Altona and St. Helens showing greatest alteration prevalence across multiple organs. This study indicates that the health of P.bassensis from Altona, St. Helens, and Mornington to a lesser extent, are currently compromised, potentially due to complex pollutant exposures which require further investigation

Uneasily along the sand

Uneasily Along the Sand evokes the state of mind of the great Mallee poet John Shaw Neilson during a period of hospitalization for nervous exhaustion around 1900. To his bed come the voices and apparitions of all those people whom he might have met but who in life eluded him. It is a ghost community of jesters, singers and seers, who parade in harlequin costumes and recall the poet to the vanishing spirit of the Mallee forest. In particular, a Wotjobaluk man by the name of ‘Jowley’ haunts him, a man found by white people as a child abandoned in a hollow log - abandoned, lost, stolen? The sound installation ‘Mac’ (that forms part of Uneasily and which will receive its first national broadcast to coincide with Mildura Palimpsest #8) evokes their strange meeting and a kind of reconciliation of peoples and cultures with environments that remains elusive. The hospital, where Neilson heard strange voices and saw strange visions, is evoked in a video work based on a set of ‘actions’ performed in Mildura’s Old Base Hospital, and sound recordings made in Pyrenees House, Ararat (a replica of the Swan Hill Hospital where Neilson was confined). The hospital solarium is transformed into a strangely distorted Mallee paddock, of sand, barbed wire and mattresses that leak like hour glasses. Caught in the fence lines of this dream world are scraps of a woman’s dress, bed sheets inscribed with charcoaled graffiti and footprints alluding to the ‘unevennesses’ of a life. Uneasily Along the sand is inspired by Paul Carter’s recent book, ‘Ground Truthing: explorations in a creative region’. The installation of Uneasily in Mildura coincides with Opening, another work inspired by ‘Ground Truthing’ that Carter and Dirk de Bruyn have created for the big screen at Federation Square, Melbourne.

The role of lipogenesis in the development of obesity and diabetes in Israeli sand rats (Psammomys obesus)

Obesity and diabetes in Israeli sand rats, Psammomys obesus, occur with the sequential transition of animals from normal insulin sensitivity to impaired insulin sensitivity, accompanied by increased adiposity, prior to insulin resistance and obesity, in a manner similar to susceptible human populations. The current study was designed to examine the role of de novo lipid synthesis in the development of excessive weight gain in P. obesus. Sand rats were classified at 12 wk of age into three groups: A, normoglycemic normoinsulinemic; B, normoglycemic hyperinsulinemic; C, hyperglycemic hyperinsulinemic, based on glucose and insulin responses in fed sand rats. Body weight, liver weight, white adipose tissue (WAT) mass and food intake were significantly elevated in Group C compared to Group A (P < 0.05). Lipogenic rate was measured by the amount of 3H incorporated into subscapular brown adipose tissue (BAT), epidiymal WAT and liver per hour, from sand rats with and without access to food. No difference in lipogenic rate was found between the groups in BAT, indicating that this tissue is of minor importance in whole body lipogenesis in P. obesus. In the WAT there was a greater lipogenic rate with the development of obesity and hyperinsulinemia (Group B vs. Group A) but no difference in the liver. However, the onset of hyperglycemia (Group C) further stimulated WAT lipogenesis and initiated increased hepatic lipogenesis, both of which contributed to the pre-existing obesity. This study suggests that elevated lipogenesis is not the primary cause of obesity in P. obesus, as lipogenic rate only markedly increases after obesity is already present in hyperglycemic animals.

The importance of sand albedo for the thermal conditions on sea turtle nesting beaches

At Ascension Island and Cyprus, major nesting areas for green turtles (Chelonia mydas) in the Atlantic and Mediterranean, respectively, visual inspection shows some beaches are light in colour while others are darker. We objectively measured the albedo of the sand on different beaches, i.e. the percentage of the incident solar radiation that was reflected from the sand surface. At sites where albedo was recorded, we also measured the temperature of the sand at nest depths. At both rookeries, the sand temperature was markedly higher on darker beaches due to greater absorption of the incident solar radiation over the diurnal cycle. Temperature loggers buried at nest depths revealed seasonal changes in temperature on both islands, but showed that the lowest temperatures found on the darker beaches rarely dropped below the highest temperatures on the lighter beaches. Sea turtles exhibit temperature-dependent sex determination. Since sand albedo is a major avenue for the production of a range of incubation temperatures on both islands, it will also have profound implications for hatchling sex ratios. In comparison with both Ascension Island and Cyprus, for samples collected from sea turtle rookeries around the world there was an even greater range in sand albedo values. This suggests that sand albedo, a factor that has previously received little consideration, will have profound implications for nest temperatures, and hence hatchling sex ratios, for other populations and species.

Thermal conductivity of sand and its effect on the temperature of Loggerhead Sea Turtle (Caretta Caretta) nests

The conductivity of sand at a depth of 30–50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0·611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0·694. The sand was highly variable in its grain structure. The dominant variability (80·6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (> 1 mm) and small (< 500 μm) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84·1% of the variation in conductivity. Moisture content of the sand (always < 5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

Rapid development of non-alcoholic steatohepatitis in Psammomys obesus (Israeli Sand Rat)

Background and AimsA major impediment to establishing new treatments for non-alcoholic steatohepatitis is the lack of suitable animal models that accurately mimic the biochemical and metabolic characteristics of the disease. The aim of this study was to explore a unique polygenic animal model of metabolic disease as a model of non-alcoholic steatohepatitis by determining the effects of 2% dietary cholesterol supplementation on metabolic and liver endpoints in Psammomys obesus (Israeli sand rat).MethodsP. obesus were provided ad libitum access to either a standard rodent diet (20% kcal/fat) or a standard rodent diet supplemented with 2% cholesterol (w/w) for 4 weeks. Histological sections of liver from animals on both diets were examined for key features of non-alcoholic steatohepatitis. The expression levels of key genes involved in hepatic lipid metabolism were measured by real-time PCR.ResultsP. obesus fed a cholesterol-supplemented diet exhibited profound hepatomegaly and steatosis, and higher plasma transaminase levels. Histological analysis identified extensive steatosis, inflammation, hepatocyte injury and fibrosis. Hepatic gene expression profiling revealed decreased expression of genes involved in delivery and uptake of lipids, and fatty acid and triglyceride synthesis, and increased expression of genes involved in very low density lipoprotein cholesterol synthesis, triglyceride and cholesterol export.ConclusionsP. obesus rapidly develop non-alcoholic steatohepatitis when fed a cholesterol-supplemented diet that appears to be histologically and mechanistically similar to patients.

In hot pursuit : fluctuating mating system and sexual selection in sand lizards

A changing climate is expected to have profound effects on many aspects of ectotherm biology. We report on a decade-long study of free-ranging sand lizards (Lacerta agilis), exposed to an increasing mean mating season temperature and with known operational sex ratios. We assessed year-to-year variation in sexual selection on body size and postcopulatory sperm competition and cryptic female choice. Higher temperature was not linked to strength of sexual selection on body mass, but operational sex ratio (more males) did increase the strength of sexual selection on body size. Elevated temperature increased mating rate and number of sires per clutch with positive effects on offspring fitness. In years when the “quality” of a female's partners was more variable (in standard errors of a male sexual ornament), clutches showed less multiple paternity. This agrees with prior laboratory trials in which females exercised stronger cryptic female choice when male quality varied more. An increased number of sires contributing to within-clutch paternity decreased the risk of having malformed offspring. Ultimately, such variation may contribute to highly dynamic and shifting selection mosaics in the wild, with potential implications for the evolutionary ecology of mating systems and population responses to rapidly changing environmental conditions.

Babes in the sand and flying predators : touristic corruption, exoticism and neocolonialism in Chandani Lokugé’s 'Turtle Nest'

In Chandani Lokugé’s Turtle Nest the Sri Lankan beach is a savage environment, a dystopia, where local children are molested by Western paedophile tourists. This essay examines representations of child vulnerability, exoticism, neocolonialism and envy in the novel. It reads these issues in the context of postcolonial tourism in Sri Lanka and elsewhere. It establishes connections between the commodification of children in Lokugé’s story and the real-world progress of exoticist tourism.