bluuebunny/crossref_metadata_2025 huggingface dataset:
Valproate synergizes with purine nucleoside analogues to induce apoptosis of B‐chronic lymphocytic leukaemia cells
Authors: Bouzar Amel Baya , Boxus Mathieu , Defoiche Julien , Berchem Guy , Macallan Derek , Pettengell Ruth , Willis Fenella , Burny Arsène , Lagneaux Laurence , Bron Dominique , Chatelain Bernard , Chatelain Christian , Willems Luc
Published: November 2008

Resistance to chemotherapy and drug toxicity are two major concerns of chronic lymphocytic leukaemia (B‐CLL) treatment by purine nucleoside analogues (PNA, i.e. fludarabine and cladribine). We hypothesized that targeting epigenetic changes might address these issues and evaluated the effect of the histone deacetylase inhibitor valproate (VPA) at a clinically relevant concentration. VPA acted in a highly synergistic/additive manner with fludarabine and cladribine to induce apoptosis of B‐CLL cells. Importantly, VPA also restored sensitivity to fludarabine in B cells from poor prognosis CLL patients who became resistant to chemotherapy. Mechanism of apoptosis induced by VPA alone or combined with fludarabine or to cladribine was caspase‐dependent and involved the extrinsic pathway. VPA, but neither fludarabine nor cladribine, enhanced the production of reactive oxygen species (ROS) and inhibition of ROS withN‐acetylcysteine decreases apoptosis of CLL cells. VPA stimulates hyperphosphorylation of p42/p44 ERK, cytochromecrelease and overexpression of Bax and Fas. Together, our data indicate that VPA may ameliorate the outcome of PNA‐based therapeutic protocols and provide a potential alternative treatment in both the relapsed and front‐line resistant patients and in patients with high risk features.
Factors influencing the yield of brown trout,Salmo truttam.lacustrisL., in northern Finnish lakes
Authors: VEHANEN T.
Published: November 2008

AbstractLake‐to‐lake variation in brown trout,Salmo truttam.lacustrisL., yield from stocking was examined in 34 lakes in northern Finland. The trout were mainly stocked as 2–3‐year‐old fish. Catch statistics were compiled with information on water quality, water level fluctuations, fishing effort and lake geomorphology. Absolute brown trout yields (kgha‐1) increased with increasing stocking rate, but there was an indication of non‐linearity at higher stocking densities. Relative yields (kg per thousand trout released) were highest at low stocking rates. Stepwise multiple regression analysis was used to determine the best predictive model for lake‐to‐lake variability in brown trout yields. Seventeen measured regressands were used initially, and then replaced with scores obtained in a principal component analysis of highly correlated water quality variables and species‐specific fish yields. Three major determinants of brown trout yields in these lakes were found in both analyses: fish community, stocking rate and fishing effort. Brown trout yields from stocking were higher in lakes with proportionally high yields of vendace or vendace and whitefish and proportionally low yields of pike.
Recaptures and resource use of native and non‐native brown trout, Salmo trutta L., released in a Norwegian lake
Authors: L'ABÉE‐LUND J.H , LANGELAND A.
Published: November 2008

Abstract Rate of recapture (gill netting), habitat use, and diet of three strains of stocked brown trout, Salmo trutta L., were compared with resident brown trout in a Norwegian lake. The strains originated from an alpine lake, from a boreal lake, and from the native brown trout population in the lake. Overall recapture rate was 5–8% for all strains. The low recapture rate could be due to the relatively small size at stocking; mean fish length varied between 13.1 and 14.5 cm with strain and stocking method. Two years after release, the frequency of the different strains decreased from about 12% in the first year to stabilize at about 1%. The alpine strain showed the highest overall recapture rate, whereas the native strain was recaptured at an intermediate rate. The overall recapture rate of scatter‐planted brown trout was higher than that of spot‐planted brown trout. Immediately after being stocked, introduced fish ate less and had a less‐varied diet than resident trout; however, stocked fish adopted a natural diet within the first summer. The distribution of trout between the pelagic and the upper epibenthic habitat was similar for both the resident and the stocked brown trout. Results indicate that the habitat use of stocked brown trout is adaptive and becomes similar to that of indigenous fish.
Long‐term changes in the sea‐age at maturity and seasonal time of return of salmon,Salmo salarL., to Scottish rivers
Authors: SUMMERS D.W.
Published: November 2008

AbstractUsing catch data, changes in salmon,Salmo salarL., sea‐age and seasonal return time were compared between several Scottish east coast rivers over the last 150–200 years. Parallel long‐term trends were found, suggesting common influences affecting salmon at sea. Long‐term associations with marine environmental factors were investigated by literature review and comparisons with an index of Icelandic sea‐ice abundance. Apparent associations were shown to exist since about 1900, although the cause was not demonstrated. However, over a longer timescale, the same associations were not apparent. Unique gradual marine changes since 1900 may have resulted in perceptible associations with salmon data which may otherwise be imperceptible when short‐term marine environmental variability is greater than long‐term variability. Marine factors must affect salmon, but the complexity of the marine environment and controls on age at maturity and time of return mean that a retrospective analysis cannot be expected to identify the causal factors.
Depredation of commercial and recreational fisheries in a Danish fjord by cormorants, Phalacrocorax carbo sinensis, Shaw
Authors: DIEPERINK C.
Published: November 2008

Abstract The conflict between the cormorant, Phalacrocorax carbo sinensis Shaw, and commercial and recreational fisheries was investigated in the foraging area of a cormorant colony of 5000 breeding pairs in Horsens Fjord, Denmark. Depredation of commercial pound nets was studied by stocking a large net pen with hatchery‐reared rainbow trout, Oncorhynchus mykiss (Walbaum). When avian predation was precluded with a cover net, background mortality was around 15% day‐1. When the cover net was removed, mortality increased to 98% day‐1. Direct observation revealed that a flock of cormorants emptied the pound net in about 30 min, consuming 110 fish weighing a total of approximately 50 kg. The cormorants were able to catch trout weighing more than 1 kg, i.e. almost 50% of their own body weight. The impact of the cormorant colony on recreational fishing in the area was studied by stocking Carlin‐tagged sea trout, Salmo trutta L., smolts into the two rivers that drain into the fjord. The cormorant colony lies between the river outlets and the open sea. Tag recovery from a 3‐year programme was only about 2%, compared with about 10% for smolts stocked in areas of low cormorant density.
A simple model for predicting ecological impacts of introduced aquatic organisms: a case study of common carp, Cyprinus carpio L., in the Sepik‐Ramu River Basin, Papua New Guinea
Authors: COATES D. , ULAIWI W.K.
Published: November 2008

Abstract Practical models for predicting the impacts of introduced biota are urgently required to assess the benefits and risks of introductions. The simple method described predicts the ecological consequences of an introduction through potential competition between species based on elementary niche classifications. The model's predictions are tested against field data for common carp, Cyprinus carpio L., which escaped from fish farms during a study of the feasibility of fish stock enhancement in a large river basin. Recorded effects of carp are based on pre‐ and post‐carp gillnet catches, observations of local villagers, socio‐economic censuses and other sources of data. The predicted ecological interactions of common carp are in broad agreement with those recorded. The method can assist pre‐introduction assessments and is particularly useful where limited data exist. In this particular study, common carp have contributed significantly to an improved capture fishery by fortuitous accident; production from aquaculture was negligible. High niche overlap between carp and certain resident fish species is predicted and this may be of more consequence in highland than lowland regions. Organisms introduced/transferred for aquaculture should be assessed within a much wider forum. The intended impacts of an introduction/ transfer, which in the case study were entirely erroneous, is an area in need of considerable attention.
Historical changes in age structure of Atlantic salmon, Salmo salar L., in the River Eo, northern Spain
Authors: BRANA F. , GARRIDO R. , NICIEZA A.G.
Published: November 2008

Abstract Variations in the age structure and number of Atlantic salmon, Salmo salar L., running into the River Eo in northern Spain were assessed from catch records of sport fisheries for the period 1949 to 1991. The analysis focused on two periods (1951–1960 and 1981–1991) for which more complete data on fish number, size and age were available. Over the whole period, no evidence for a decline in the total salmon run was found, but the last few years revealed significant changes in both the number and age structure of salmon caught. The catches were mainly composed of multi‐sea‐winter salmon, and this did not change from the 1950s to the 1980s as the proportion of grilse remained unchanged. However, since 1980, there was a marked decline in both the proportion of 3‐sea‐winter salmon (versus 2‐sea‐winter fish) and the frequency of previous spawners among the multi‐sea‐winter salmon. These changes were probably linked because most of the previous spawners re‐entered the river as 3‐sea‐winter or older salmon. River age of salmon caught in the 1950s was low and constant (about 90% of the catch had smolted at one year) but the mean age of smolting increased in the 1980s.
Predation of Atlantic salmon, Salmo salar L., smolts and parr by red‐breasted mergansers, Mergus serrator L., on two Scottish rivers
Authors: FELTHAM M.J.
Published: November 2008

Abstract Current models estimating the impact of red‐breasted mergansers, Mergus serrator L., on salmon, Salmo salar L., fisheries in Scotland fail to take account of any annual variation in the proportion of the diet that is smolts. During the 1987–1990 smolt runs, the annual variation in the diet of mergansers was estimated from the stomach contents of birds shot on two Scottish rivers. The proportion of salmon in the diet was greatest early in the smolt run (76–91% by weight), and contained proportionately more smolts than later in the run, when coarse fish were more prominent. There was little annual variation in the proportion of the diet that was juvenile salmon. However, the proportion of these fish that were smolts, was twice as great in some years than in others and this appeared to be independent of estimated annual smolt production in the rivers.
Distribution and feeding of juvenile Pacific salmon in freshwater tidal creeks of the lower Fraser River, British Columbia
Authors: LEVINGS C.D. , BOYLE D.E. , WHITEHOUSE T.R.
Published: November 2008

Abstract This study examined juvenile salmonid use of a freshwater tidal creek system draining a wetland on the floodplain of the lower Fraser River, British Columbia, Canada. Chum, Oncorhynchus keta (Walbaum), chinook, O. tshawytscha (Walbaum), and sockeye, O. nerka (Walbaum), salmon fry were abundant in the tidal creeks in spring. The fry were found in non‐natal habitat up to 1.5 km from the main channel of the river. The salmon fry ate dipteran adults, larvae and pupae, cyclopoid and harpacticoid copepods, and Collembola. Mysids Neomysis mercedis Holmes (Walbaum), and amphipods, Crangonyx richmondensis occidentalis (Hubricht and Harrison), were also consumed. The upper reaches of an undisturbed creek were the winter rearing habitat for presmolt coho salmon, O. kisutch (Walbaum), where this species ate dipteran pupae and larvae as well as a freshwater isopod, Asellus communis Say (Walbaum).
Factors affecting the fishing power of sardine fishing vessels and implications for the management of the fisheries on Lake Kariba, Zimbabwe
Authors: CHIFAMBA P. C.
Published: November 2008

Abstract The factors important in determining fishing power in the Lake Kariba sardine, Limnothrissa miodon (Boulenger, 1906), fishery were identified using data from the major fishing area of the lake, the Kariba basin, for the periods 1980–1982 and 1988–1990. Comparisons were carried out using fishing power calculated from the mean catch of some standard vessels. Three methods were used for identification of the important attributes. Analysis of variance (ANOVA) was carried out for each component to compare the mean fishing power at all levels within each variable. Multiple regression analysis was used to build predictive models and to determine the factors which best predict fishing power. Factor analysis was used to ordinate vessel types and examine any vessel groupings related to fishing power. Factor analysis showed that vessel and net size were the most important variables. Vessels without engines for propulsion, of low value and without radios had less fishing power than the other vessels in the fleet. Vessels from the same company had similar fishing power, suggesting that some unmeasured variable such as quality of management linked to the fishing companies had a significant effect on catch. The factors which were important in determining catch were length of vessel, depth of the net, presence and absence of echo sounder, mobility, the type of light, number and wattage of the underwater lights in the 1988–1990 fishing period. Vessel length and net category were most important in the period 1980–1982. The models accounted for between 37.6 (1981) and 61.2% (1988) of the variation in fishing power. During the development of the fishery, there has been a change from purse seine to lift nets, and increases in the use of echo sounders, engines for the propulsion of vessels and radios, all of which could have increased effective fishing effort.
Seasonal habitat use by brook trout, Salvelinus fontinalis (Mitchill), in a second‐order stream
Authors: JOHNSON J.H. , DROPKIN D.S.
Published: November 2008

Abstract Seasonal habitat use by over‐yearling and under‐yearling brook trout, Salvelinus fontinalis (Mitchill), was examined in a second‐order stream in north‐central Pennsylvania, USA. The habitat occupied by brook trout and available habitat were determined in a 0.5‐km stream reach during the spring, summer and autumn of 1989 and the spring and summer of 1990. Cover, depth, substrate and velocity were quantified from over 2000 observations of individual brook trout. Habitat used by under‐yearling brook trout was more uniform between seasons and years than that used by over‐yearling brook trout. Over‐yearling brook trout occupied areas with more cover and greater depth than did under‐yearling brook trout, suggesting ontogenetic shifts in these variables. Differences for velocity and substrate were not as great as those for cover and depth. The selection of areas with low water velocities governed trout habitat use in spring, whereas cover and depth were the most important habitat variables in summer and autumn. Principal component analysis showed that available habitat and trout habitat centroids diverged most in spring, indicating that habitat selection by brook trout may be greatest at this time.
A comparison of electric fishing and gillnetting to examine the effects of anthropogenic disturbance on riverine fish communities
Authors: GROWNS I.O. , POLLARD D.A. , HARRIS J.H.
Published: November 2008

Abstract Quantitative electric fishing and multiple mesh‐size gillnetting of fish communities in the Hawkesbury‐Nepean River system, near Sydney, were carried out upstream of, within and well below each of three major points of treated sewage effluent discharge. Approximately half of the fish sampled were caught by electric fishing, comprising 515 individuals in 3 h of electric fishing (172 fish per hour). The remaining 439 fish were caught in 72 h of gillnetting (six fish per hour). In total, 16 fish species were collected by electric fishing and only seven species by the gill nets. Differences were found in the total abundances and numbers of species collected by each method in relation to points of treated sewage effluent discharge, but neither community variable showed consistent differences between the areas above, within and well below points of treated sewage effluent discharge in all three river regions. However, classification and ordination of electric fishing catch data produced distinct fish community groups in relation to sewage discharge, while similar analyses of the gillnetting data failed to reveal such differences in community structure. It was suggested that the increased sampling efficiency of electric fishing, both in terms of the number of fish sampled per unit effort and number of species collected, allowed for significant increases in the power of univariate and multivariate analysis methods in detecting such environmental disturbances in large rivers.
Freshwater reconditioning and ranching of Atlantic salmon, Salmo salar L., kelts: growth and reproductive performance
Authors: MOFFETT I.J.J. , KENNEDY G.J.A. , CROZIER W.W.
Published: November 2008

Abstract Artificial reconditioning of Atlantic salmon in fresh water over two successive years produced kelt survival rates of 28% and 55% in years one and two, respectively. Eye damage and failure to identify non‐feeders were important factors contributing to high mortalities. Average fecundities of kelts reconditioned for the first (1220 ova kg‐1) and second (1093 ova kg‐1) year were lower than obtained for virgin control fish (1590 and 1728 ova kg‐1 respectively). Average survival to swim‐up for progeny of first‐year (64.5%) and second‐year (71.4%) reconditioned fish were similar to survival of virgin control fish progeny (72.3% and 68.9% respectively).

Ranched kelts showed better growth parameters than for freshwater reconditioning but had lower average fecundities (1310 ova kg‐1 compared with 1820 ova kg‐1) and lower average progeny survival to swim‐up (60.8% compared with 88.6%) than their control group.
Fishes and the environmental status of South African estuaries
Authors: WHITFIELD A. K.
Published: November 2008

Abstract More than 100 fish species are associated with southern African estuaries, many of which are caught by recreational anglers and/or commercial fishermen. Mismanagement of either a catchment or an estuary invariably leads to an impoverished system which is of little value to fishes or people. By taking this cause‐and‐effect scenario to its logical conclusion, it should be possible to assess the ‘state’ of an estuary by monitoring the biological ‘health’ of the aquatic community. Fishes are a dominant and highly visible component of the estuarine fauna and, by virtue of their key positions in the aquatic food web, can reflect either natural or anthropogenic alterations to the environment. In addition, their mobility enables them to respond rapidly to both deteriorating and improving estuarine conditions. Such attributes may assist scientists and managers in being better able both to assess the magnitude of detrimental impacts, and to monitor the ecosystem response to ameliorative actions. This paper attempts to show that an understanding of the biology and ecology of fishes associated with estuaries can lead to the identification of threats to the environment and result in improved management of these systems. The use of fish communities as an indicator of estuarine health is also examined, and ways of incorporating biological and ecological data into decision‐support systems are discussed. The adoption of a set of environmental quality objectives for South African estuaries, together with a system of appropriate environmental quality standards, is recommended.
Potential effects of global warming on northern European freshwater fish and fisheries
Authors: LEHTONEN H.
Published: November 2008

Abstract Global warming is expected to result in considerable changes in northern European freshwater fish populations, fisheries and aquaculture. Shifts towards cyprinid and percid dominance in fish assemblages are expected, together with a decrease and collapse of salmonid and other coldwater fish populations. Most of the evident changes will occur in shallow lakes, where no thermal stratification occurs. The potential ranges of some fish species will shift northwards but pronounced changes will occur in the relative abundance of individual fish species. Total fish production will increase but because of changed composition of fish communities the commercial and recreational value of catches will decrease. Salmonid aquaculture productivity will increase provided that fish farmers adapt to new circumstances and cold, oxygenated water is available in larger quantities during summer.
The performance of sea trout, Salmo trutta L., stocks from the Burrishoole system western Ireland, 1970–1994.
Authors: POOLE W. R. , WHELAN K. F. , DILLANE M. G. , COOKE D. J. , MATTHEWS M.
Published: November 2008

Abstract Since 1975, with partial recoveries in 1979 and 1984–1986, the numbers of finnock and adult sea trout, Salmo trutta L., in the Burrishoole system, western Ireland, have declined. The population decreased sharply from 1987, and collapsed in 1989 and 1990. Finnock were virtually absent in 1989 and one‐year maidens equally so in 1990. Sea trout smolt recruitments from 1992 to 1994 were the lowest recorded since 1970. The modal fork length of finnock decreased from 28 cm in 1987 to 26 cm in 1990. Up until 1989, the percentage return of smolts, as finnock, ranged from 11.4 to 32.4%. In 1989 a minimum was reached at 1.5%, with values of 10.0, 3.7, 7.4 and 9.9% from 1990 to 1994. Marine survival of smolts, to total first return to fresh water, historically ranged from 19 to 66%. Survival dropped to 1.8% in 1989. Observed changes in the structure of the sea trout population and the collapse in marine survival suggest that the current west of Ireland sea trout problem is based in the marine habitat.
Evaluation of a portable electrode array for a resistivity fish counter
Authors: SMITH I.P. , JOHNSTONE A.D.F. , DUNKLEY D.A.
Published: November 2008

Abstract This study aimed to develop and test an electrode array for a resistivity fish counter that could be easily installed in a small river without a weir. An electrode array consisting of three steel cables laid in parallel across the stream channel and connected to a microprocessor‐based counter was tested in an Atlantic salmon, Salmo salar L., spawning tributary. The accuracy of the counter was assessed by observing fish movements with closed‐circuit television. Most salmon moving upstream were registered correctly (90% overall). Detection of downstream movement was less reliable (60% overall), as a consequence of downstream swimming behaviour. The accuracy of the downstream count was improved by tensioning the cable electrodes, but remained lower than that of the upstream count. Since salmon swam repeatedly up‐ and downstream, this discrepancy resulted in an overestimate of the net upstream count. The accuracy of the downstream count needs to be improved before a bed‐mounted electrode array could be used for routine salmon counting.
Post‐stocking dispersal of European grayling, Thymallus thymallus (L.), in a semi‐natural experimental stream
Authors: CARLSTEIN M. , ERIKSSON L.‐O.
Published: November 2008

Abstract Artificially hatched and reared juvenile European grayling, Thymallus thymallus (L.), from three natural populations were released into an experimental stream. Two of the populations were from lakes and the third population was from a river. Post‐stocking dispersal was studied by recapturing fish in traps and by electric fishing after each of the stocking exercises. On all three occasions the first fish to be recaptured were caught in a trap about 400 m downstream from the release site, within 5–12 min of release. Proportions of stocked grayling juveniles recaptured by electric fishing in the fast‐flowing section of the experimental stream (the rapids) were 9.9%, 46.7% and 16.6% after the first, second and third stocking, respectively. No significant population‐specific difference was found between fish caught in the downstream trap and fish recaptured in the rapids. The uppermost part of the rapids (stretch 1) and the catch in the upstream trap was dominated by fish of riverine origin. Post‐stocking migration was influenced by sex but not by body size. Females showed a greater propensity to stay in the rapids compared with males. Implications of the results for stocking grayling in natural streams and regulated rivers are discussed.
On the age and growth of bogue, Boops boops (L.), from the Portuguese coast
Authors: GORDO L.S.
Published: November 2008

Abstract Between 1984 and 1990, a total of 4892 bogues, Boops boops (L.) were caught in Peniche and 4352 in Algarve, with the total length varying from 6 to 40 cm. Age determination was carried out using direct reading and back‐calculation on the otoliths. Von Bertalanffy growth equations, based on mean lengths per age group, were established for both samples and using both methods. Applying the Hotelling T2 test to the growth parameters of those equations, it was concluded that there were no significant differences between them. This conclusion allowed the validation of the two methods employed, and the combination of the data from Peniche and Algarve into one single age‐length key from which a growth equation for the Portuguese coast was calculated and described as: Lt = 45.918 {1‐exp [‐0.124 (t + 2.628)]}.
The status of the recently introduced fish Leucaspius delineatus (Cyprinidae) in Great Britain
Authors: FARR‐COX F. , LEONARD S. , WHEELER A.
Published: November 2008

Abstract The fish Leucaspius delineatus (Heckel) (Cyprinidae) has been introduced to southern England as a result of importation as an ornamental fish. It is now established at several waters (lakes, canals, and lowland rivers) in Hampshire and Somerset. It appears to be well adapted to spread beyond these centres as a result of its small size at sexual maturity and reproductive biology. A preliminary assessment of its diet and fecundity, and notes on its breeding habits are given.
Differences in the time of river entry of Atlantic salmon, Salmo salar L., spawning in different parts of the River North Esk
Authors: SUMMERS D. W.
Published: November 2008

Abstract Spawning adult Atlantic salmon, Salmo salar L., were sampled in five tributaries of the River North Esk, Scotland, during the winters 1989/90 and 1990/91. The fish furthest upriver had higher sea‐ and smolt‐ages and the one‐sea‐winter fish were smaller and more coloured than those spawning further downstream. These differences indicate that the uppermost tributaries are populated by fish which enter the river early in the year and the lowest tributaries by fish entering late in the year. Exactly why such a structure exists is not clear, but it is suggested that these differences may be adaptive and that selection effects may continually be modifying these populations.
A preliminary appraisal of the contribution of recreational fishing to the fisheries sector in north‐west Trinidad
Authors: MIKE A. , COWX I. G.
Published: November 2008

Abstract An assessment of the recreational fishery in north‐west Trinidad was made by questioning participants about the principal fishing methods used, location of activities, catches, effort and cost of fishing. Surface handline methods (live baiting [à la vive] and trolling) and rod and line (banking) were the most common methods used and were pursued mainly in the summer months (April to August). Total fish landings from the fishery were estimated at 1000 t year‐1, equivalent to about 10% of commercial catches for Trinidad. The principal species caught were kingfish, Scomberomorus cavalla (Cuv.), carite, Scomberomorus brasiliensis (Cuv.), cavalli, Caranx hippos (L.), snappers, Lutjanus spp., and groupers, Epinephelus spp. Many of the fishermen sold their catch to offset the costs of the fishing trip and thus competed with commercial fishermen. Recommendations for monitoring and possibly regulating the fishery through a licensing scheme are made.
Changes in the fish and fisheries ecology of a large man‐made lake in Tanzania, 1965–94
Authors: BAILEY R. G.
Published: November 2008

Abstract Nyumba ya Mungu Reservoir in northern Tanzania has a maximum surface area of 180 km2, an average depth of 6 m, and contains moderately saline, fertile water. The postimpoundment decade, 1965–74, was characterised by a spectacular rise and fall of a tilapiabased fishery. Since then a gill‐net fishery catching large numbers of large, periphyton‐grazing tilapias has given way to a mainly beach‐seine fishery producing large numbers of small, phytoplankton‐feeding Oreochromis esculentus (Graham). Yields remain higher than preimpoundment predictions but the size at maturity of all tilapia species has fallen and few larger than 15 cm TL are caught. These changes, and others in the fish community trophic structure, are chiefly explained by changes in the littoral environment and fishing pressures. Nyumba ya Mungu provides a case history of developments in the tilapia fishery of a man‐made river lake conducted on an essentially laissez‐faire basis.
Impact of sediment and nutrient inputs on growth and survival of tadpoles of the Western Toad
Authors: WOOD SYLVIA L. R. , RICHARDSON JOHN S.
Published: November 2008

1. Sediment and nutrient loading in freshwater systems are leading causes of aquatic habitat degradation globally. We investigated the impacts of fine‐sediment and nutrient additions on the growth and survival of western toad (Bufo boreas) tadpoles and emergent metamorphs in mesocosm and exclosure experiments.

2. Mesocosm tanks received weekly pulses of fine sediments to create initial concentrations of 0, 130 and 260 mg L−1 of suspended sediment and either bi‐weekly additions of nutrients (N = 160 μg L−1, P = 10 μg L−1) or no additions in a factorial design. Within mesocosms, tadpole exclosures allowed for quantification of tadpole grazing pressure on periphyton biomass, chlorophyll‐a and sediment deposition.

3. Tadpoles receiving sediment additions experienced slower growth rates and reduced survival to metamorphosis, although no effects of treatment were detected on size at metamorphosis or time to metamorphosis. Nutrient additions also lowered survival, but had no impact on other measured parameters of tadpole fitness. Dissections and gut content analysis revealed that tadpoles ingested sediment in large quantities altering the proportion of the organic content of ingested food.

4. Together these results suggest that although sediment was readily consumed by tadpoles, its presence in the larval environment had an overall negative effect on tadpole growth and survival, although not as severe as predicted.
Reorganization of a large marine ecosystem due to atmospheric and anthropogenic pressure: a discontinuous regime shift in the Central Baltic Sea
Authors: MÖLLMANN CHRISTIAN , DIEKMANN RABEA , MÜLLER‐KARULIS BÄRBEL , KORNILOVS GEORGS , PLIKSHS MARIS , AXE PHILIP
Published: November 2008

Marine ecosystems such as the Baltic Sea are currently under strong atmospheric and anthropogenic pressure. Besides natural and human‐induced changes in climate, major anthropogenic drivers such as overfishing and anthropogenic eutrophication are significantly affecting ecosystem structure and function. Recently, studies demonstrated the existence of alternative stable states in various terrestrial and aquatic ecosystems. These so‐called ecosystem regime shifts have been explained mainly as a result of multiple causes, e.g. climatic regime shifts, overexploitation or a combination of both. The occurrence of ecosystem regime shifts has important management implications, as they can cause significant losses of ecological and economic resources. Because of hysteresis in ecosystem responses, restoring regimes considered as favourable may require drastic and expensive management actions. Also the Baltic Sea, the largest brackish water body in the world ocean, and its ecosystems are strongly affected by atmospheric and anthropogenic drivers. Here, we present results of an analysis of the state and development of the Central Baltic Sea ecosystem integrating hydroclimatic, nutrient, phyto‐ and zooplankton as well as fisheries data. Our analyses of 52 biotic and abiotic variables using multivariate statistics demonstrated a major reorganization of the ecosystem and identified two stable states between 1974 and 2005, separated by a transition period in 1988–1993. We show the change in Baltic ecosystem structure to have the characteristics of a discontinuous regime shift, initiated by climate‐induced changes in the abiotic environment and stabilized by fisheries‐induced feedback loops in the food web. Our results indicate the importance of maintaining the resilience of an ecosystem to atmospherically induced environmental change by reducing the anthropogenic impact.
Litter decomposition in grasslands of Central North America (US Great Plains)
Authors: BONTTI ELIANA E. , DECANT JOSEPH P. , MUNSON SETH M. , GATHANY MARK A. , PRZESZLOWSKA AGNIESZKA , HADDIX MICHELLE L. , OWENS STEPHANIE , BURKE INGRID C. , PARTON WILLIAM J. , HARMON MARK E.
Published: November 2008

One of the major concerns about global warming is the potential for an increase in decomposition and soil respiration rates, increasing CO2 emissions and creating a positive feedback between global warming and soil respiration. This is particularly important in ecosystems with large belowground biomass, such as grasslands where over 90% of the carbon is allocated belowground. A better understanding of the relative influence of climate and litter quality on litter decomposition is needed to predict these changes accurately in grasslands. The Long‐Term Intersite Decomposition Experiment Team (LIDET) dataset was used to evaluate the influence of climatic variables (temperature, precipitation, actual evapotranspiration, and climate decomposition index), and litter quality (lignin content, carbon : nitrogen, and lignin : nitrogen ratios) on leaf and root decomposition in the US Great Plains. Wooden dowels were used to provide a homogeneous litter quality to evaluate the relative importance of above and belowground environments on decomposition. Contrary to expectations, temperature did not explain variation in root and leaf decomposition, whereas precipitation partially explained variation in root decomposition. Percent lignin was the best predictor of leaf and root decomposition. It also explained most variation in root decomposition in models which combined litter quality and climatic variables. Despite the lack of relationship between temperature and root decomposition, temperature could indirectly affect root decomposition through decreased litter quality and increased water deficits. These results suggest that carbon flux from root decomposition in grasslands would increase, as result of increasing temperature, only if precipitation is not limiting. However, where precipitation is limiting, increased temperature would decrease root decomposition, thus likely increasing carbon storage in grasslands. Under homogeneous litter quality, belowground decomposition was faster than aboveground and was best predicted by mean annual precipitation, which also suggests that the high moisture in soil accelerates decomposition belowground.
Seasonal variation in enzyme activities and temperature sensitivities in Arctic tundra soils
Authors: WALLENSTEIN MATTHEW D. , MCMAHON SHAWNA K. , SCHIMEL JOSHUA P.
Published: November 2008

Arctic soils contain large amounts of organic matter due to very slow rates of detritus decomposition. The first step in decomposition results from the activity of extracellular enzymes produced by soil microbes. We hypothesized that potential enzyme activities are low relative to the large stocks of organic matter in Arctic tundra soils, and that enzyme activity is low at in situ temperatures. We measured the potential activity of six hydrolytic enzymes at 4 and 20 °C on four sampling dates in tussock, intertussock, shrub organic, and shrub mineral soils at Toolik Lake, Alaska. Potential activities of N‐acetyl glucosaminidase, β‐glucosidase, and peptidase tended to be greatest at the end of winter, suggesting that microbes produced enzymes while soils were frozen. In general, enzyme activities did not increase during the Arctic summer, suggesting that enzyme production is N‐limited during the period when temperatures would otherwise drive higher enzyme activity in situ. We also detected seasonal variations in the temperature sensitivity (Q10) of soil enzymes. In general, soil enzyme pools were more sensitive to temperature at the end of the winter than during the summer. We modeled potential in situβ‐glucosidase activities for tussock and shrub organic soils based on measured enzyme activities, temperature sensitivities, and daily soil temperature data. Modeled in situ enzyme activity in tussock soils increased briefly during the spring, then declined through the summer. In shrub soils, modeled enzyme activities increased through the spring thaw into early August, and then declined through the late summer and into winter. Overall, temperature is the strongest factor driving low in situ enzyme activities in the Arctic. However, enzyme activity was low during the summer, possibly due to N‐limitation of enzyme production, which would constrain enzyme activity during the brief period when temperatures would otherwise drive higher rates of decomposition.
Climate change effects on physiology and population processes of hosts and vectors that influence the spread of hemipteran‐borne plant viruses
Authors: CANTO TOMÁS , ARANDA MIGUEL A. , FERERES ALBERTO
Published: November 2008

Plant virus diseases constitute one of the limiting factors to the productivity of agriculture. Changes in host plants and insect vector populations that might result from climate change (their geographical distribution range, their densities, migration potential and phenology) could affect the spread of plant viruses. At the individual level, alterations in plant physiological processes that are relevant to their molecular interactions with viruses, like changes in metabolism, leaf temperature, and their effects on some processes, like the temperature‐sensitive antiviral resistance based in RNA silencing, can also influence the ability of individual plants to control viral infections. In order to assess the impact that climate change may have on the incidence and spread of hemipteran‐borne plant viruses, its potential effects on virus/plant interactions and hemipteran insect vectors, as well as other operating processes, which could exacerbate or mitigate them, are identified and analyzed in this review.
Vascular invasion in breast cancer; an overview of recent prognostic developments and molecular pathophysiological mechanisms
Authors: Mohammed R A A , Ellis I O , Lee A H S , Martin S G
Published: November 2008

Vascular invasion (VI) is an essential step in breast cancer metastasis and the main cause of morbidity and mortality from the disease. Detection of VI in the primary tumour is a marker of metastatic potential. The prognostic value of VI in breast cancer has been known for more than four decades, but its application in clinical practice is still fraught with difficulties due to the limited number of studies conducted on large numbers of well‐characterized patients with long‐term follow‐up. Detection of VI in the primary tumour is currently assessed using sections stained with haematoxylin and eosin, which has some disadvantages. A number of vascular markers have been used to improve detection of VI; however, their sensitivity and specificity, as endothelial markers, vary considerably. In this review we describe the evolution of the prognostic importance of VI and the recent pathomolecular mechanisms that contribute to the ability of breast cancers to invade through vessels, in addition to the types, locations and methods of detection of vascular invasion.
Genome‐wide analysis of genes related to ovary activation in worker honey bees
Authors: Thompson G. J. , Kucharski R. , Maleszka R. , Oldroyd B. P.
Published: November 2008

A defining characteristic of eusocial animals is their division of labour into reproductive and nonreproductive specialists. Here, we used a microarray study to identify genes associated with functional sterility in the worker honey bee Apis mellifera. We contrasted gene expression in workers from a functionally sterile wild‐type strain with that in a mutant (anarchist) strain selected for high rates of ovary activation. We identified a small set of genes from the brain (n = 7) and from the abdomen (n = 5) that are correlated in their expression with early stages of ovary activation. Sterile wild‐type workers up‐regulated two unknown genes and a homologue of Drosophila CG6004. By contrast, reproductive anarchist workers up‐regulated genes for the yolk protein vitellogenin, venom peptides and a member of the AdoHycase superfamily, among others. The differentially expressed genes identified are likely to be involved in early differentiation into sterile and reproductive worker phenotypes and may therefore form part of the gene networks associated with the regulation of honey bee worker sterility. Our study may have lacked sufficient power to detect all but a minority of biologically relevant changes taking place; however, the differential expression of vitellogenin and a putative AdoHycase suggests that our screen has captured core reproductive genes and that ovary activation may involve an epigenetic mechanism.
Isolation and functional characterization of two independently‐evolved fatty acid Δ12‐desaturase genes from insects
Authors: Zhou X.‐R. , Horne I. , Damcevski K. , Haritos V. , Green A. , Singh S.
Published: November 2008

We report the first isolation and characterization of insect fatty acid Δ12‐desaturase genes, AdD12Des from house cricket (Acheta domesticus) and TcD12Des from the red flour beetle (Tribolium castaneum), responsible for the production of linoleic acid from oleic acid. Sequence analysis shows the cricket and flour beetle Δ12‐desaturase genes have evolved independently from all previously known Δ12‐desaturases and are much more closely related to the archetypal stearoyl‐Coenzyme A‐acting desaturase from rat than to the phospholipid‐acting Δ12‐desaturases widely reported in plants. Phylogenetic and functional analysis indicates the cricket AdD12Des gene may have evolved from an ancestral Δ9‐desaturase. By contrast, the beetle Δ12‐desaturase is distantly related to the cricket genes and beetle Δ9‐desaturases suggesting evolution by an independent route. Linoleic acid has key physiological roles in insects and this is the first report of genes capable of producing this essential fatty acid in higher animals.
Chikungunya‐Wolbachiainterplay inAedes albopictus
Authors: Tortosa P. , Courtiol A. , Moutailler S. , Failloux A.‐B. , Weill M.
Published: November 2008

A severe Chikungunya (CHIK) outbreak recently hit several countries of the Indian Ocean. On La Réunion Island,Aedes albopictuswas incriminated as the major vector. This mosquito species is naturally co‐infected with two distinct strains of the endosymbiontWolbachia, namelywAlbA andwAlbB, which are increasingly attracting interest as potential tools for vector control. A PCR quantitative assay was developed to investigateWolbachia/mosquito host interactions. We show thatWolbachiadensities are slightly decreased in CHIK virus (CHIKV)‐infected females. We measured the impact of CHIKV replication on a lysogenic virus: WO bacteriophage. Our data indicate that WO is sheltered bywAlbB, likely at a single copy per bacteria, and that CHIKV replication is not a physiological stress triggering WO entrance into the lytic cycle.
Fluorescence microscopy and flow cytometry in measuring activated caspases in human spermatozoa
Authors: Brugnon F. , Ouchchane L. , Verheyen G. , Communal Y. , Van der Elst J. , Tournaye H. , Janny L. , Grizard G.
Published: November 2008

Staining of spermatozoa with the fluorescein‐Val‐Ala‐Asp‐fluoromethylketone has already been performed on ejaculated sperm samples, using fluorescence microscopy (FM) or flow cytometry (FCM) in order to score activated caspases. This assay may help in assessing apoptosis and its role in male fertility. The present study compares the above two techniques in order to adopt the most accurate method for detection in human frozen‐thawed testicular, epididymal and ejaculated spermatozoa. The analyses were carried out on frozen/thawed testicular (n = 14), epididymal (n = 8) and ejaculated (n = 10) sperm samples. Activated caspases were detected in living spermatozoa using fluorescein‐labelled inhibitors of poly‐caspases (FLICA). For the measurements by FM, the same‐observer and different‐observer reliability were assessed in testicular and epididymal sperm samples. The inter‐method (FM and FCM) reliability was assessed both in epididymal and ejaculated sperm samples. The reliability was evaluated by intraclass correlation coefficient (ICC) and the differences between paired measurements from the same sample were tested by Wilcoxon test for matched pairs. For the same‐observer and the different‐observer data, the ICC were 0.980 and 0.986. In testicular suspensions, the presence of different types of germinal and somatic cells hampers the differentiation of stained spermatozoa by FCM. For the inter‐method reliability, the ICC was 0.903. A lower proportion of the viable spermatozoa stained with FLICA was observed by using FM (−6.60 ± 7.38 %, mean ± SD; p = 0.003) compared with FCM. To measure the proportion of spermatozoa with activated caspases by this test, FM is a highly accurate and reliable method whatever the sperm origin (ejaculate, epididymis, and testis). FCM cannot be used for testicular samples but seems to be more appropriate for analysis of epididymal and ejaculated sperm samples. The systematic lower proportion by FM in measuring the proportion of stained viable spermatozoa with FLICA involves that only the data measured by the same method (FM or FCM) may be compared.
E‐communication among mothers of infants and toddlers in a community‐based cohort: a content analysis
Authors: Hall Wendy , Irvine Valerie
Published: November 2008

Title.  E‐communication among mothers of infants and toddlers in a community‐based cohort: a content analysis.

Background.  Early psychosocial support for families is regarded as inadequate. Employed women with young children can feel isolated from other families. Most parent e‐mail lists are in a read‐only format, with parents receiving informative e‐mails from a corporation or a commercially motivated initiative. In an increasingly virtual age, it is important to examine parents’ use of online support groups initiated by parents.

Method.  We used a qualitative descriptive design to conduct an inductive content analysis of archived threads of e‐mail from 40 middle class Canadian mothers involved in a grass‐roots online support cohort that shared birth year and geographical community. Two hundred and ninety‐two pages of single‐spaced mother‐based communication that occurred from June 2004 to May 2005 were analysed.

Findings.  Mothers used cohort‐based electronic communication to build a local community, request and provide emotional support, share information and facilitate learning, and provide validation for the ‘normalcy’ of other women’s mothering experiences. They shared stories and feelings, expressed sympathy, offered accolades, expressed appreciation for shared experiences, conveyed gratitude for support, and shared beliefs and expectations. Mothers anticipated childrearing difficulties shared strategies, exchanged advice, confirmed others’ strategies and shared information.

Conclusion.  Women in particular geographical areas can use asynchronous mail systems to share information with and obtain support from other mothers. Cohort‐based electronic communication could be particularly important in rural areas where travel is restricted for women and access to professional support is limited.