bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood group and protein polymorphism gene frequencies for seven breeds of horses in the United States
Authors: Bowling Ann Trommershausen , Clark Robert S.
Published: August 2010

Gene frequencies at 20 blood group and protein polymorphism loci (A, C, D, K, P, Q, U, Al, Tf, Pi, Xk, Es, Gc, PGD, CA, Cat, PGM, AP, Hb and PHI) are given for seven horse breeds in the United States (Thoroughbred, Arabian, Standard bred, Morgan, Quarter Horse, Paso Fino and Peruvian Paso). These data are used to calculate that the battery of tests is at least 96% effective for recognizing incorrect paternity in these breeds. In addition to paternity testing, these tests can be applied to studies of breed relationships.
Prediction of the halothane (Hal) genotypes of pigs by deducing Hal, Phi, Po2, Pgd haplotypes of parents and offspring: results from a large‐scale practice in Swedish breeds
Authors: Gahne B. , Juneja R. K.
Published: August 2010

Results from a large‐scale study, comprising 75 different breeding herds, are reported on predicting the halothane (Hal) genotypes of individual pigs by making use of the known close linkage between Hal and three C blood marker loci (Phi, Po2, Pgd). The parents haplotypes (involving Hal and marker loci) were determined from the HAL phenotypes (halothane test results) and marker loci phenotypes of their offspring in the first one or two litters studied. In subsequent litters of the Hal‐marker loci haplotyped parents, the offspring's expected Hal genotypes could be predicted on the basis of the marker loci haplotypes inherited by them. By comparing the expected and observed HAL phenotypes of offspring in subsequent litters, the predicted Hal genotype was found to be correct in 90–95 % of the 4000 offspring (from Nn × Nn and Nn × nn matings) of Swedish Landrace and Yorkshire breeds studied.

The order of the three marker loci was confirmed as Phi‐Po2‐Pgd but the position of Hal with regards to Phi could not be resolved. The recombination frequencies between the most distant loci in this region, viz. Hal‐Pgd and Phi‐Pgd, were estimated to be 3–4.5 % and 4–6 %, respectively. The easy and rapid electrophoretic techniques described in the study to phenotype PHI, PO2, PGD, also allowed phe‐notyping of six other polymorphic protein systems on the same gels. Thus Hal genotyping and effective parentage control can be conducted simultaneously.
The position of the epistatic S locus in the halothane linkage group in pigs
Authors: Van Zeveren A. , Van de Weghe A. , Bouquet Y. , Varewyck H.
Published: August 2010

The linkage of the Phi, Pgd, Po2, S, H and halothane sensitivity loci was followed in a Belgian Landrace family, heterozygous for these systems over 6 generations. Recombination next to the S locus occurred mainly in pigs belonging to this particular family. From this investigation the position of the S locus is proved to be outwith the Phi‐Pgd region, next to Phi. Therefore the gene sequence S ‐ Phi ‐ Hal ‐H‐ Po2 ‐Pgd is proposed. Higher recombination rates were observed in the female parental line of the multiheterozygous family when compared to the male parental line. Additional data from animals, unrelated to this strain, confirm the evidence of close linkage of the S system to the nearest marker loci.
Relationships between blood groups, isozymes and halothane reaction in pigs from a selection experiment1
Authors: Grashorn M. , Müller Elisabeth
Published: August 2010

German Landrace pigs (n= 1500) were halothane‐tested and blood samples were taken for the determination of A‐O and H blood types as well as for the determination of PHI and 6‐PGD isozymes. The pigs originated from two generations (7th and 8th) of a selection experiment ‘selection for activity of NADPH‐generating enzymes in backfat of pigs’. The selection lines are E‐, E+ (selection for low and high enzyme activity), U‐ (selection for low ultrasonic backfat thickness) and K (control). Preliminary results show an average proportion of halothane‐susceptible animals of 49 %. The frequencies of halothane‐positive pigs amount to 60 %, 46 %, 70 % and 30 % in lines E‐, E+, U‐ and K, respectively. The investigation shows a non‐random combination of the marker genes caused by linkage disequilibrium, especially in line E‐. Recombination frequencies between the loci vary from 0 % to 18 %.
Meloxicam pharmacokinetics in renal impairment
Authors: Boulton‐Jones J. M. , Geddes C. G. , Heinzel G. , Türck D. , Nehmiz G. , Bevis P. J. R.
Published: August 2010

AimsThe aim of the present study was to determine how the pharmacokinetics of meloxicam are affected by kidney dysfunction and consequently to define the appropriate dose for the use of meloxicam in patients with mild or moderate renal impairment.

MethodsMeloxicam was administered to subjects with mild (creatinine clearance 41–60 ml min−1) to moderate (20–40 ml min−1) renal impairment compared with normal renal function (>60 ml min−1). Thirty‐eight subjects received meloxicam 15 mg once daily over 9 days. Meloxicam plasma concentrations were determined from blood samples taken during the study and pharmacokinetic parameters calculated according to noncompartmental methods.

ResultsSubjects with no or mild renal impairment showed sinular pharmacokinetic profiles (geometric mean AUCSS(%gCV) 55 (33%)vs55 (38%) μg ml−1h). Subjects with moderate renal impairment demonstrated lower total plasma meloxicam concentrations (AUCSS35 (50%) μg ml−1h, with corresponding higher plasma clearance (P= 0.013) compared with subjects with no renal impairment. However, this was combined with higher meloxicam free fractions in moderately impaired subjects such that free meloxicam concentrations were similar in all three groups. Meloxicam was well tolerated with few adverse events occurring and no difference in incidence observable between groups.

ConclusionsOn the basis of these results there is no necessity for a dosage adjustment when administering meloxicam to patients with mild to moderate renal impairment.
Modulation of CYP2EI activity by isoniazid in rapid and slow N‐acetylators
Authors: O'Shea Diarmuid , Kim Richard B. , Wilkinson Grant R.
Published: August 2010

AimsAn investigation was undertaken to compare the effects of isoniazid pretreatment on the CYP2El ‐mediated 6‐hydroxylation of chlorzoxazone in healthy subjects of known N‐acetylator phenotype.

MethodsCYP2E1 activity was estimated based on the 6‐hydroxylation of chlorzoxazone following single dose (250 mg) oral administration to seven slow and eight rapid N‐acetylators who were in good health. Separate studies were performed prior to and 14 days after the subjects received 300 mg isoniazid dady. Additional investigations were undertaken 2 and 16 days after discontinuing treatment with the antitubercular agent.

ResultsConcomitant administration of chlorzoxazone with the final dose of isoniazid resulted in reduced metabolism in both phenotypes; however, the extent of inhibition of 6‐hydroxylation was greater in the slow N‐acetylators—about 80% vs60%. Two days after stopping isoniazid administration, chlorzoxazone's pharmacokinetic parameters had returned to their baseline values and remained constant for a further 14 days in the rapid acetylators. In contrast, chlorzoxazone's 6‐hydroxylation in slow acetylators was increased by about 60% compared with baseline at 2 days after dicontinuing isoniazid but had returned to its initial value 14 days later.ConclusionsThe interphenotypic difference in the time‐dependent interactions of isoniazid with CYP2E1 probably reflect a higher drug exposure in slow acetylators. Inhibition of CYP2E1 activity occurs in both N‐acetylator phenotypes but is less extensive in fast acetylators, during the time that effective levels of isoniazid are present in the body. Increased CYP2E1 activity reflective of enzyme induction, on the other hand, is only observable following isoniazid's elimination and is more extensive in slow than rapid acetylators. Even then, however, such induction is relatively modest and of short duration.
Therapeutic drug monitoring of cytotoxic drugs
Authors: Lennard L.
Published: August 2010

Therapeutic drug monitoring is not routinely used for cytotoxic agents. There are several reasons, but one major drawback is the lack of established therapeutic concentration ranges. Combination chemotherapy makes the establishment of therapeutic ranges for individual drugs difficult, the concentration‐effect relationship for a single drug may not be the same as when that drug is used in a drug combination. Pharmacokinetic optimization protocols for many classes of cytotoxic compounds exist in specialized centres, and some of these protocols are now part of large multicentre trials. Nonetheless, methotrexate is the only agent which is routinely monitored in most treatment centres. An additional factor, especially in antimetabolite therapy, is the existence of pharmacogenetic enzymes which play a major role in drug metabolism. Monitoring of therapy could include assay of phenotypic enzyme activities or genotype in addition to, or instead, the more traditional measurement of parent drug or drug metabolites. The cytotoxic activities of mercaptopurine and fluorouracil are regulated by thiopurine methyltransferase (TPMT) and dihydropyrimidine dehydrogenase (DPD), respectively. Lack of TPMT functional activity produces life‐threatening mercaptopurine myelotoxicity. Very low DPD activity reduces fluorouracil breakdown producing severe cytotoxicity. These pharmacogenetic enzymes can influence the bioavailability, pharmacokinetics, toxicity and efficacy of their substrate drugs.
Semi‐mechanistic pharmacokinetic/pharmacodynamic modelling of the antimalarial effect of artemisinin
Authors: Gordi Toufigh , Xie Rujia , Jusko William J.
Published: August 2010

Purpose

To characterize artemisinin pharmacokinetics (PK) and its antimalarial activity in vivo.

Methods

Artemisinin salivary concentration and parasite count data were obtained from Vietnamese malaria patients receiving two different dosage regimens. PK data were analysed using a previously developed semiphysiological model incorporating autoinduction of eliminating enzymes. A pharmacodynamic (PD) model reflecting different stages of the parasite life‐cycle was developed and fitted to the data. The model included visible and invisible compartments as well as sensitive, insensitive, and injured parasite stages. Salivary artemisinin concentrations functioned as the driving force for the observed decrease in the number of parasites.

Results

Large interindividual variability was observed in both PK and PD data. The PK model described reasonably well the observed decrease in salivary concentrations after repeated drug administration. The preinduction hepatic extraction ratio of artemisinin was estimated to be 0.87 with a volume of distribution of 27 L. Artemisinin half‐life averaged 0.7 h. Incorporation of a saturable hepatic elimination affecting the first‐pass extraction as well as a higher intrinsic clearance in female patients resulted in the best fit of the model to the data. The PD model described the decrease in the number of parasites during the course of treatment well. The longest mean transit time of parasites from sensitive, visible to invisible to insensitive visible stages was found to be 34.5 h through one life‐cycle. The half‐life of injured parasites was 2.7 h.

Conclusions

The proposed semimechanistic PK/PD model successfully described the time course of both salivary artemisinin concentrations after repeated dosing and the number of parasites in patients treated with the drug.
Detection of prognostically relevant genetic abnormalities in childhood B‐cell precursor acute lymphoblastic leukaemia: recommendations from the Biology and Diagnosis Committee of the International Berlin‐Frankfürt‐Münster study group
Authors: Harrison Christine J. , Haas Oskar , Harbott Jochen , Biondi Andrea , Stanulla Martin , Trka Jan , Izraeli Shai
Published: August 2010

Treatment of childhood acute lymphoblastic leukaemia (ALL) has improved considerably in recent years. A contributing factor has been the improved stratification for treatment according to a number of factors, including genetic determinants of outcome. Here we review the current diagnostic criteria of genetic abnormalities in precursor B‐ALL (BCP‐ALL), including the relevant technical approaches and the application of the most appropriate methods for the detection of each abnormality. The abnormalities with the most significant impact for treatment and management of BCP‐ALL are t(9;22)(q34;q11)/BCR‐ABL1, t(4;11)(q21;q23)/MLL‐AFF1 and near‐haploidy/low hypodiploidy for high risk stratification and, to a lesser extent, t(12;21)(p13;q22)/ETV6‐RUNX1 and high hyperdiploidy for good risk management. Apart from the numerical abnormalities, these can be routinely tested for by reverse transcription polymerase chain reaction, providing a basic yet informative screen. However, cytogenetics, particularly fluorescence in situ hybridization may provide reliable alternative detection methods dependent upon the preferred technical approach within each protocol.
MicroRNA‐21 expression in neonatal blood associated with antenatal immunoglobulin E production and development of allergic rhinitis
Authors: Chen R.‐F. , Huang H.‐C. , Ou C.‐Y. , Hsu T.‐Y. , Chuang H. , Chang J.‐C. , Wang L. , Kuo H.‐C. , Yang K. D.
Published: August 2010

Background
The prevalence of allergic diseases has increased in the past decades. It is unknown whether expression of certain microRNAs (miRNAs) in neonatal leucocytes is correlated to IgE production and/or allergic diseases.

Objective
This study investigated the association of miRNA expression in neonatal leucocytes with cord blood IgE (CBIgE) elevation and development of allergic disease.

Methods
We screened for the expression of a panel of 157 miRNAs in mononuclear leucocytes from human umbilical cord blood (CB) samples with elevated CBIgE and tracked the association of down‐regulated miRNA expression to the miRNA‐targeted gene expression and to children with allergic rhinitis (AR).

Results
Among the initial screen of 10 CB samples with elevated CBIgE, expression of eight of the 157 miRNAs was low. Of these eight down‐expressed miRNAs, three remained down‐regulation in a validation with other 20 CB samples, and two of the three miRNAs, miR‐21 and miR‐126, were significantly lower in monocytes from AR children. Further analysis of mRNA expression of the miR‐21‐targeted genes identified that TGFBR2 expression on monocytes was significantly up‐regulated in CB with elevated CBIgE, and in AR patients. Transfection of miR‐21 precursor into monocytes from patients with AR increased miR‐21 expression and decreased TGFBR2 expression.

Conclusion
This study demonstrated the first in the literature that lower miR‐21 expression in CB and increased TGFBR2 expression is associated with antenatal IgE production and development of AR.

Cite this as: R.‐F. Chen, H.‐C. Huang, C.‐Y. Ou, T.‐Y. Hsu, H. Chuang, J.‐C. Chang, L. Wang, H.‐C. Kuo and K. D. Yang, Clinical & Experimental Allergy, 2010 (40) 1482–1490.
Cytokine receptors: structure and signal transduction
Authors: FOXWELL B M J , BARRETT K , FELDMANN M
Published: August 2010

In the past 2–3 years, a number of cytokine receptors have been partly characterized and the cDNA for the ligand binding chains cloned. This has revealed that cytokine receptors are complex. Many are known to be multichain receptors (e.g. IL-2) and since their mechanism of signal transduction is not obvious, it is likely that other proteins yet to be defined take part in the signalling process. The cloning of the receptor ligand binding chain has revealed that (unlike cytokines), there are major families of receptors. Some are members of the Ig supergene family (e.g. IL-1 receptor), others are members of the nerve growth factor receptor family (e.g. TNF), but the majority are members of the haematopoietic growth factor family (e.g. IL-3, GM-CSF). Yet other cytokine receptors do not belong to a family, e.g. IFN-γ.
Soluble apoptosis molecules in primary biliary cirrhosis: analysis and commitment of the Fas and tumour necrosis factor-related apoptosis-inducing ligand systems in comparison with chronic hepatitis C
Authors: Pelli N , Floreani A , Torre F , Delfino A , Baragiotta A , Contini P , Basso M , Picciotto A
Published: August 2010

Apoptosis in the liver is generated mainly by the Fas system. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has been proposed recently as a new apoptotic inducer. In the liver environment hepatocytes and biliary epithelial cells express TRAIL receptors which are up-regulated by increased levels of bile acids and during viral hepatitis. As for FasL, a soluble form of TRAIL has been described. To explore the commitment and level of activation of these two apoptotic systems in patients affected by primary biliary cirrhosis (PBC) or chronic hepatitis C (CH-C), a comparative study was drawn. Thirty patients with PBC on ursodeoxycholic acid have been enrolled. This group was compared with 30 patients with CH-C and with 20 healthy subjects. Soluble Fas ligand (sFasL) and soluble TRAIL (sTRAIL) levels were evaluated by double determinant immune assay and enzyme-linked immunosorbent assay (ELISA), respectively. Soluble FasL molecules were higher in PBC compared to CH-C (P = 0·009). Soluble FasL was not detected in controls. Soluble TRAIL was significantly higher in CH-C patients compared to PBC (P = 0·0001). Soluble TRAIL levels were higher in PBC and in CH-C than in controls (P = 0·015 and P < 0·001, respectively). No correlation between sFasL and sTRAIL, stage of disease, liver histology in each disease and cytolysis was present. Our data show different levels of commitment of TRAIL and Fas apoptosis-inducing systems in CH-C and PBC. Thus a different prominent role of TRAIL and Fas systems in the pathogenesis of these two conditions can be speculated: the former by inducing the death of infected hepatocytes, the latter by mediating the disappearance of bile duct.
The role of T helper 17 (Th17) and regulatory T cells (Treg) in human organ transplantation and autoimmune disease
Authors: Afzali B , Lombardi G , Lechler R I , Lord G M
Published: August 2010

Uncommitted (naive) murine CD4+ T helper cells (Thp) can be induced to differentiate towards T helper 1 (Th1), Th2, Th17 and regulatory (Treg) phenotypes according to the local cytokine milieu. This can be demonstrated most readily both in vitro and in vivo in murine CD4+ T cells. The presence of interleukin (IL)-12 [signalling through signal transduction and activator of transcription (STAT)-4] skews towards Th1, IL-4 (signalling through STAT-6) towards Th2, transforming growth factor (TGF)-β towards Treg and IL-6 and TGF-β towards Th17. The committed cells are characterized by expression of specific transcription factors, T-bet for Th1, GATA-3 for Th2, forkhead box P3 (FoxP3) for Tregs and RORγt for Th17 cells. Recently, it has been demonstrated that the skewing of murine Thp towards Th17 and Treg is mutually exclusive. Although human Thp can also be skewed towards Th1 and Th2 phenotypes there is as yet no direct evidence for the existence of discrete Th17 cells in humans nor of mutually antagonistic development of Th17 cells and Tregs. There is considerable evidence, however, both in humans and in mice for the importance of interferon (IFN)-γ and IL-17 in the development and progression of inflammatory and autoimmune diseases (AD). Unexpectedly, some models of autoimmunity thought traditionally to be solely Th1-dependent have been demonstrated subsequently to have a non-redundant requirement for Th17 cells, notably experimental allergic encephalomyelitis and collagen-induced arthritis. In contrast, Tregs have anti-inflammatory properties and can cause quiescence of autoimmune diseases and prolongation of transplant function. As a result, it can be proposed that skewing of responses towards Th17 or Th1 and away from Treg may be responsible for the development and/or progression of AD or acute transplant rejection in humans. Blocking critical cytokines in vivo, notably IL-6, may result in a shift from a Th17 towards a regulatory phenotype and induce quiescence of AD or prevent transplant rejection. In this paper we review Th17/IL-17 and Treg biology and expand on this hypothesis.
Reduced apoptosis and increased inflammatory cytokines in granulomas caused by tuberculous compared to non-tuberculous mycobacteria: role of MPT64 antigen in apoptosis and immune response
Authors: Mustafa T , Wiker H G , Mørkve O , Sviland L
Published: August 2010

Inhibition of apoptosis of infected macrophages by pathogenic mycobacteria is suggested to be an important virulence mechanism, but little is known about the mycobacterial proteins involved in the inhibition of apoptosis. In this study we investigated differences in apoptosis and immune response and their correlation with the expression of Mycobacterium tuberculosis complex-specific secretory protein MPT64 in lesions caused by tuberculous or non-tuberculous mycobacteria by analysing the in situ expression of apoptosis-related proteins (FasL, Fas, Bax, Bcl-2), apoptotic cells, inflammatory cytokines [tumour necrosis factor (TNF)-α, interleukin (IL)-10, transforming growth factor (TGF)-β, interferon (IFN)-γ] and MPT64 antigen. The discrimination of mycobacteria was made by nested polymerase chain reaction (PCR) amplification of IS6110, which is specific for M. tuberculosis complex organisms. Forty-seven cases of lymphadenitis with necrotic granulomas were evaluated. With nested PCR, 30/47 cases were positive for M. tuberculosis. MPT64 antigen was detected specifically in the PCR-positive cases. Granulomas caused by tuberculous mycobacteria had fewer apoptotic cells, higher numbers of cells expressing TNF-α and TGF-β and less extensive necrosis than granulomas caused by non-tuberculous mycobacteria. There was a significant negative correlation between apoptotic cells and the number of cells expressing MPT64 antigens, suggesting a role for MPT64 protein in the inhibition of apoptosis. Granulomas with higher amounts of MPT64 also showed a greater number of cells expressing TGF-β than those with lower amounts of MPT64. In conclusion, this study supports the hypothesis that inhibition of apoptosis is a virulence mechanism for tuberculous mycobacteria. Correlation of MPT64 antigen with expression of macrophage deactivating cytokines and reduced apoptosis suggests its role in pathogenesis and bacillary persistence.
The use of liquid chromatography in the study of cadmium speciation in soil solutions from polluted soils
Authors: TILLS ALISON R. , ALLOWAY B. J.
Published: August 2010

Chromatographic methods were used in an attempt to identify the various species of cadmium in soil solution. Exclusion and reverse‐phase chromatography using HPLC showed that cadmium existed in the form of low‐molecular weight, highly polar species. Ion‐exchange chromatography was used to divide soil solution cadmium into cationic, anionic and neutral species. Cadmium was found to be mainly in the form of inorganic cationic species, including the free ionic form, Cd2+, and some as neutral species, possibly organic as well as inorganic, especially in soils of higher pH. Anionic species were relatively unimportant. These results showed general agreement with those of other authors using computer models to predict cadmium speciation in soil solution.
Soil solution aluminium activity related to theoretical A1 mineral solubilities in four Australian soils
Authors: HELYAR K. R. , CONYERS M. K. , MUNNS D. N.
Published: August 2010

Four soils were treated with HNO3, CaCO3and K2SO4to enable observation of the response of the soil solution composition and the solution A1 ion activity (Al3+) to the treatments and to time. The clay fraction of three of the soils was dominated by illite, kaolinite and quartz. The fourth was minated by kaolinite and iron oxides. The initial pH in 0.01 M CaCl2varied between 4.0 and 5.0 and the organic carbon content from 0.7 to 1.1%. The soil solutions from soils dominated by kaolinite, illite and quartz were generally supersaturated with respect to quartz and well ordered kaolinite, and unsaturated with respect to illite. The soil solutions from the soil dominated by kaolin and iron oxide were generally unsaturated with respect to quartz but still saturated with respect to ell crystallized kaolin. Within mineral groups such as Al2SiO5compounds, A12Si2O5(OH)4(kaolinite group), and Al(OH)3(A1 oxide) minerals, the more soluble forms became less supersaturated or unsaturated with time for many treatments.

Lime treatment usually increased the ion activity product of AI(OH)3in all soils, and of minerals with the composition, Al2SiO5, in the illite/kaolinite soils. Acid treatment reduced the apparent solubility of Al(OH)3, and the A1 silicates in the Al2SiO5, and Al2, Si2, O5,(OH)4, mineral groups on all soils. These results are interpreted to indicate that lime treatment led to the formation of trace quantities of more soluble A1 minerals that subsequently controlled (Al3+), whereas acid treatment dissolved trace quantities of such minerals leaving less soluble minerals to control (Al3+). The results suggest that, in mineral soils such as these, (Al3+) is under the control of inorganic dissolution and precipitation processes. These processes conform to expectations given the free energy of various inorganic aluminium compounds. Furthermore the sequence of dissolution and formation processes appears to be governed by the Gay‐Lussac—Ostwald step rule.
In situ characterization of hydraulic conductivities of individual soil profile layers during infiltration over long time periods
Authors: Carrick S. , Almond P. , Buchan G. , Smith N.
Published: August 2010

Several studies have raised serious doubts about the suitability of small cores for measuring water‐movement attributes, due to their potential to provide unrealistic representation of macropore connectivity and abundance. This study explored the potential of lysimeter‐scale experiments to calculate the hydraulic conductivity, K(ψm), of undisturbed soil layers in a matric potential (ψm) range between 0 and −4 kPa. Four large lysimeters were collected from a Dystric Cambisol. For each lysimeter a tension infiltrometer supplied infiltrating water under suctions of 0, 0.5, 1 and 1.5 kPa. Soil water dynamics were measured in situ using arrays of tensiometers, at depths corresponding with layer boundaries. The results show clearly that infiltration and drainage rates are intimately linked to temporal ψm dynamics, which themselves are determined by preferential flow and soil‐layer interactions. A quasi‐steady state was identified as when infiltration matched drainage, and ψm measurements showed each layer had a stable hydraulic gradient, which then allowed in situ determination of the K(ψm) relationship of individual soil layers. For this soil K(ψm) is distinctly different for each soil layer, and these differences are consistent among the four lysimeters. A consistent feature is that all layers have a distinct change in the slope of the K(ψm) relationship, in the ψm range of −0.5 to −1.5 kPa, highlighting a dual‐porosity character. The whole‐column infiltration behaviour was strongly linked to the K(ψm) relationship of the surface layer (0–2 cm depth), and therefore hydraulic characterization of this layer should be a critical component of a soil survey.
Lobster larval transport in the southern Gulf of St. Lawrence
Authors: CHASSÉ JOËL , MILLER ROBERT J.
Published: August 2010

A bio‐physical semi‐Langrangian model was developed to follow the drift and abundance of lobster larvae from hatching to settlement as post‐larvae. The geographic domain encompasses Northumberland Strait and the areas surrounding Prince Edward Island in the southern Gulf of St. Lawrence. The model was run for ten larval seasons, 1983–87 and 1997–2001, representing two periods of egg production. The model was forced with tides, winds, heat fluxes, and marine and freshwater fluxes at open boundaries. Biological inputs were location, date, and density of larvae at hatching, development rates, a time window and a minimum bottom temperature required for successful settlement, and two scenarios of daily mortality. Net drift was west to east but stronger on the north than the south side of Prince Edward Island. The hatch was greater in the second 5‐yr period, but the spatial patterns of settlement were similar. For both mortality scenarios, the same five of the 24 larval source areas were important in providing settlers. Horizontal shear of larval distribution indicates fishing communities were dependent on the hatch from fishing grounds of multiple upstream communities. Variation in daily and annual post‐larval settlement was greatest north of Prince Edward Island. From the 24 source areas there was an eightfold range in the fraction of larvae surviving to settlement, with advection into deep water an important cause of mortality. Four to five possible fishery management areas were identified using multidimensional scaling to group sink areas having shared source areas. We hypothesize leaky discontinuity in connectivity between these groups.
Distribution and drift pathways of Greenland halibut (Reinhardtius hippoglossoides) during early life stages in the eastern Bering Sea and Aleutian Islands
Authors: SOHN D. , CIANNELLI L. , DUFFY‐ANDERSON J. T.
Published: August 2010

We describe the spatial distribution and dispersal pathways of Greenland halibut (Reinhardtius hippoglossoides) early life stages based on historical field data from the eastern Bering Sea and adjacent water along the eastern Aleutian Islands. Our results indicate that Greenland halibut from preflexion larvae to newly settled juveniles have a long pelagic duration and are subject to extended drift pathways. Hatching may occur in deep water, below 530 m, and larvae rise in the water column as they grow. Flexion/postflexion larvae are mostly found around the Pribilof Islands over the middle shelf (50–100‐m isobaths) in July, and settling occurs during late summer on the middle shelf near St. Matthew Island. However, given that age‐1 individuals were primarily found on the outer shelf, it appears that Greenland halibut actively move to deeper water with age (or size). The mechanisms of slope–shelf connectivity in preflexion larvae may be related to the Bering Slope Current in the vicinity of both Bering and Pribilof Canyons. This study shows that Greenland halibut early life stages have extensive horizontal ontogenetic migrations in the Bering Sea, and utilize a range of geographic areas over the basin and slope along the Aleutian Islands and in the eastern Bering Sea. Based on these results, it is hypothesized that settlement success and recruitment of Greenland halibut may be influenced by variability in currents and flows of the Bering Sea slope and shelf during their transport.
Thermal habitat of striped bass (Morone saxatilis) in coastal waters of northern Massachusetts, USA, during summer
Authors: NELSON GARY A. , ARMSTRONG MICHAEL P. , STRITZEL‐THOMSON JENNIFER , FRIEDLAND KEVIN D.
Published: August 2010

Striped bass, Morone saxatilis, were captured and released with temperature‐measuring data storage tags in Salem Sound, Massachusetts, to collect data on their thermal preferences in coastal and marine waters and to identify environmental factors that may influence temperatures experienced during their summer residence. Striped bass recaptured during summer of 2006 (21 of 151 releases) experienced a wide range of temperatures (6.5–28.0°C) while at‐large for 1–53 days. Overall mean temperature and standard deviation selected by striped bass recaptured in Salem Sound during the longest commonly‐shared duration of time (3–12 July) were 17.8 and 3.57°C, respectively. Comparison of temperature data between fish and 13 vertical arrays in Salem Sound revealed that striped bass experienced higher and more variable temperatures, and that daily changes in temperature actually experienced were unrelated to daily changes in surrounding ambient temperature. Regular cyclical changes in temperature of all striped bass and vertical arrays were identified as influences of the local tide, which contributed about a 2°C change in temperature, on average, over the complete cycle. Most striped bass appeared to limit their activities to depths shallower than the lower limit of the thermocline, above which temperatures generally exceed 9.0°C in Salem Sound. Therefore, it is likely that the vertical distribution of striped bass is restricted by the low temperatures below this depth. An implication of this finding is that the spatial distribution of striped bass may be defined coarsely by knowledge of the distribution of temperature in coastal areas.
Seasonal spawning and wind‐regulated retention‐dispersal of early life stage Atlantic cod (Gadus morhua) in a Newfoundland fjord
Authors: KNICKLE D. CRAIG , ROSE GEORGE A.
Published: August 2010

Sequential ichthyoplankton surveys were used to determine the spatial and temporal distribution of eggs and larvae over coastal spawning grounds of Atlantic cod (Gadus morhua) in Smith Sound, Trinity Bay, Newfoundland, during the spring and summer of 2006 and 2007. Egg densities showed similar patterns for both years with two peaks in abundance in spring (March–April) and late summer (late July). A clear progression of development stages (1–4) was observed in spring and summer in 2006 and summer in 2007, suggesting retention of eggs within the Sound during these periods. Modelled predictions of vertical egg distributions indicated eggs were broadly distributed near the surface during spring (March–April), but were concentrated below the pycnocline (>10 m) within the inner portions of the Sound during the summer months (July–August). Back‐calculated peaks in spawning based on water temperatures were estimated at 11 and 4 April for 2006 and 2007, respectfully, with late season peaks centred on 21–24 July for both years. Environmental data indicated cooler water temperatures and periods of high wind stress in spring, and warmer, calmer periods late summer, consistent with higher retention and faster development times on the spawning grounds later in the season. We conclude that spring and summer spawning events result in different distributions of early life stages and may lead to different distributions of juvenile and adult fish.
Diets and food consumption rates of pelagic fish in Lake Malawi, Africa
Authors: ALLISON E.H. , IRVINE K. , THOMPSON A.B. , NGATUNGA B.P.
Published: August 2010

Studies of diel feeding periodicity, rates of food consumption and diet composition of pelagic fish were undertaken to resolve the dispute regarding the existence of a vacant niche for a pelagic zooplanktivore in Lake Malawi.

Six species of zooplanktivore were abundant in the offshore pelagic zone, these were:Diplotaxodon limnothrissa, D.‘bigeye’,Rhamphochromis longicepsandCopadichromis quadrimaculatus(all haplochromine cichlids),Synodontis njassae(Mochokidae) andEngraulicypris sardella(Cyprinidae). The main piscivores were cichlids of the genusRhamphochromis.

All cichlids were daytime feeders; some showed peaks in feeding activity at dawn and dusk that were related to vertical migration patterns of their prey.Synodontis njassaewas able to feed throughout the day, but fed most actively at night.

Food consumption: biomass ratios (Q/Byr‐1) calculated from diel stomach contents data were 5.87–7.13 forD. limnothrissa, 12.79 forD.‘bigeye’, 4.20–24.7 forR. longicepsand 6.45 forS. njassae.AnnualQ/Bratios for other species, which ranged from 4.74 to 9.28, were obtained from an empirical model relating food consumption to fish morphology. Published estimates were used forE. sardellaandOpsaridium microcephalum(Cyprinidae). An estimate of total prey consumption by the pelagic fish population was obtained fromQ/Bratios and fish biomass estimates from acoustic surveys covering the entire offshore pelagic zone of the lake (24 000 km2).

Diplotaxodon limnothrissa, R. longicepsandC. quadrimaculatushad a broad range of diets, with the ability to switch from crustacean zooplankton to larvae and pupae ofChaoborus edulis(Diptera) or larval and juvenileE. sardella. Diplotaxodon‘bigeye’ andS. njassaefed almost exclusively on fourth‐instar larvae and pupae ofC. edulis. Engraulicypris sardellafed mainly on crustacean zooplankton. The main prey of the large piscivorousRhamphochromisspecies wereDiplotaxodonspp. andE. sardella.

The fish community consumed only 3% of estimated crustacean zooplankton production directly. Predation pressure was intense (> 80% of estimated production consumed by predators) on late instars of the zooplanktivorousC. edulislarvae and onE. sardellalarvae.Rhamphochomisspp. consumed 22–43% of estimated production of the zooplankton‐eating fishes.

Although many members of the fish community do not feed directly on crustacean zooplankton, so that the food‐chain supporting fish production involves an extra trophic level, it is considered that the endemic fish community is well adapted to feeding on the low‐density prey in the pelagic zone, and that there is no vacant feeding niche.
Interannual variability in phytoplankton biomass and species composition in a subtropical reservoir
Authors: HARRIS GRAHAM P. , BAXTER GRAHAM
Published: August 2010

The interannual variability of the dominant phytoplankton populations is described in a subtropical reservoir in Queensland using weekly data for a 16‐year period between 1978 and 1994. North Pine Dam, Brisbane, is in an area characterized by strong interannual variability in rainfall. This variability is linked to El Nino Southern Oscillation (ENSO) events. Between 1978 and 1994 periods of drought (during strong ENSO events) were interspersed by periods of flooding rains. Rainfall on the catchment and temperature and oxygen within the dam showed strong 40‐day periodicities which also varied in strength interannually in response to ENSO events. Similar patterns of fluctuations in the 40‐day periodicity have been found elsewhere in SE Australia. Seasonal cycles of stratification in the dam were a function of both hydrographic and hydrological events. Intermittent rain storms caused partial turnovers and large outflows. As much as 90% of the dam volume was exchanged in a single flood event.

The dominant phytoplankton species were similar to those frequently found in tropical and subtropical lakes and reservoirs. The phytoplankton community switched between cyanobacterial blooms (Cylindrospermopsis, Microcystis) during drought and falling water levels and diatom blooms (Aulacoseira) in response to inflows and seasonal turnovers. There appeared to be a subtle interaction between inflows, water column stability, the periodic overturns and the occurrence of the dominant species. All the dominant species showed long periods (2–4 years) of exponential increase or decrease superimposed on top of the seasonal fluctuations in abundance. These patterns of abundance led to marked interannual variability in the phytoplankton biomass. Climate variability had a major impact on the seasonal and interannual changes of the dominant phytoplankton species.

Phytoplankton biomass tended to be depressed for about 3 months after individual storm events but the data also displayed long‐term lag effects (2–4 years) which destroyed any significant correlation between water residence time and biomass. Summer maxima of biomass dominated by cyanobacteria disappeared between 1985 and 1990 and were replaced by smaller winter peaks. The data presented here are not capable of unequivocally identifying the precise reason for these longer‐term effects. Because of the implications for water quality management in subtropical and tropical reservoirs they warrant further study.
The influence of stream invertebrate composition at neighbouring sites on local assemblage composition
Authors: SANDERSON R. A. , EYRE M. D. , RUSHTON S. P.
Published: August 2010

1. The composition of freshwater invertebrate assemblages at a location is determined by a range of physico‐chemical and biotic factors in the local environment, as well as larger‐scale spatial factors such as sources of recruits. We assessed the relative importance of the species composition of local neighbourhoods and proximal environmental factors on the composition of invertebrate assemblages.

2. Macroinvertebrate assemblages were sampled at 188 running‐water sites in the catchment of the River Rede, north‐east England. A total of 176 species were recorded.

3. Environmental data, in the form of 13 biotic and abiotic measurements that described stream physical structure, aquatic vegetation and water characteristics, were recorded for each site. Detrended correspondence analysis was then used to simplify nine of these stream environmental variables to create an index of stream structure.

4. The species composition of the invertebrate assemblages was related to the environmental variables, using an information theoretic approach. The impact of the species composition of neighbouring sites on each site was determined using Moran's I and autoregressive modelling techniques.

5. Species composition was primarily associated with water pH and stream structure. The importance of the species composition of neighbouring sites in determining local species assemblages differed markedly between taxa. The autoregressive component was low for Coleoptera, intermediate for Trichoptera and Plecoptera, and high for Ephemeroptera.

6. We hypothesise that the observed differences in the autoregressive component amongst these orders reflects variation in their dispersal abilities from neighbouring sites.
Release rates and potential fates of nitrogen and phosphorus from sediments in a eutrophic reservoir
Authors: NOWLIN WESTON H. , EVARTS JENNIFER L. , VANNI MICHAEL J.
Published: August 2010

1. Nutrients released from lake sediments can influence water column nutrient concentrations and planktonic productivity. We examined sediment nutrient release [soluble reactive phosphorus (SRP) and ammonia (NH)] at two sites in a eutrophic reservoir (Acton Lake, OH, U.S.A.) that differed in physical mixing conditions (a thermally stratified and an unstratified site).

2. Sediment nutrient release rates were estimated with three methods: sediment core incubations, seasonal in situ hypolimnetic accumulation and a published regression model that predicted sediment phosphorous (P) release rate from sediment P concentration. All three methods were applied to the deeper stratified site in the reservoir; however, we used only sediment core incubations to estimate SRP and NH release rates at the shallow unstratified site because of the lack of thermal stratification. We also compared the total P concentration (TPS) of sediments and the concentration of P in various sediment fractions at both sites.

3. Anoxic sediments at the stratified site released SRP at rates more than an order of magnitude greater than oxic sediments at the shallow unstratified site. However, P accumulated in the hypolimnion at much lower rates than predicted by sediment core incubations. In contrast, NH was released at similar rates at both sites and accumulated in the hypolimnion at close to the expected rate, indicating that P was ‘lost’ from the hypolimnion through biogeochemical pathways for P, such as precipitation with inorganic material or biological uptake and sedimentation.

4. TPS was significantly greater at the deeper stratified site and organically bound P accounted for >50% of TPS at both sites.

5. We examined the magnitude of SRP fluxes into the study reservoir in 1996 by comparing the mean summer daily SRP fluxes from anaerobic sediments, aerobic sediments, stream inflows and gizzard shad excretion. While the SRP release from anaerobic sediments was high, we hypothesise that little of this SRP gained access to the epilimnion in mid‐summer. SRP flux to the reservoir from aerobic sediments was less than from gizzard shad excretion and streams. Large interannual variability in thermocline stability, gizzard shad biomass and stream discharge volumes, will affect SRP loading rates from different sources in different years. Therefore, construction of P budgets for different years should account for interannual variation in these parameters.
Diversity in the influence of temperature on the growth rates of freshwater algae, and its ecological relevance
Authors: BUTTERWICK C. , HEANEY S. I. , TALLING J. F.
Published: August 2010

1. Growth rates of seven species of planktonic algae were determined in culture over a range of temperature from 2 to 35 °C. Additional observations on growth and viability were made for 13 species in the temperature range 20–35 °C.

2. There was a wide range of growth rates between species at their optimal temperatures, from 1.7 divisions day−1 (Asterionella formosa) to 0.3 divisions day−1 (Ceratium furcoides).

3. There were considerable differences between species for growth at low and high temperature. Certain algae, including the diatom A. formosa and the flagellates Cryptomonas marssonii, Dinobryon divergens and Eudorina unicocca var. unicocca, had growth rates of 0.4 divisions day−1 or more at 5 °C. The cyanophyte Tychonema (formerly Oscillatoria) bourrellyi, the xanthophyte Tribonema sp., the desmid Staurastrum cingulum and the large dinoflagellate C. furcoides grew poorly or not at all at this temperature. All 21 species tested could grow at 25 °C, but many – including most of the diatoms, some cyanophytes, and all the flagellates – failed to grow persistently at 30 °C. Only Aphanizomenon flos‐aquae survived with moderate increase at 35 °C, a lethal temperature for the other species.

4. The applicability was considered of proposed quantitative formulations of the rate‐temperature relationship. Simple exponential relationships applied only to very limited lower ranges of temperature. The relationship proposed by Bĕlehrádek was a better fit over a wider temperature range, but still excluded rate‐decline at high temperature.

5. The interspecific differences found are of potential significance for restrictions in natural distributions associated with season, altitude (especially above 500 m) and latitude.
Responses of a beaded Arctic stream to short‐term N and P fertilisation
Authors: BENSTEAD JONATHAN P. , DEEGAN LINDA A. , PETERSON BRUCE J. , HURYN ALEXANDER D. , BOWDEN WILLIAM B. , SUBERKROPP KELLER , BUZBY KAREN M. , GREEN ADRIAN C. , VACCA JAY A.
Published: August 2010

1. Oligotrophic Arctic streams are likely to be sensitive to changes in hydrology and nutrient inputs predicted to occur as a consequence of future climate and land use change. To investigate the potential consequences of nutrient enrichment for low‐order Arctic streams, we added ammonium‐N and phosphorous to a second‐order beaded, tundra stream on Alaska's north slope. We measured responses in nutrient chemistry, chlorophyll a standing crop, and in the breakdown and macroinvertebrate colonisation of leaf litter over a 38‐day summer period.

2. During the addition, nutrient concentrations immediately downstream of the dripper averaged 6.4 μm ammonium‐N and 0.45 μm soluble reactive P. Concentrations upstream of the dripper averaged 0.54 μm ammonium‐N and 0.03 μm soluble reactive P. Uptake of both nutrients was rapid. Concentrations were reduced on average to 28% (ammonium‐N) and 15% (inorganic P) of maximum values within 1500 m. Standing crops of chlorophyll a on standardised samplers were significantly higher by the end of the experiment. Breakdown rates of senescent willow (Salix sp.) and sedge (Carex sp.) litter and associated fungal biomass were also significantly increased by nutrient addition.

3. Fertilisation resulted in four‐ to sevenfold higher macroinvertebrate abundance and two‐ to fourfold higher macroinvertebrate biomass in litter bags, as well as an increase in late‐summer body mass of larval Nemoura stoneflies.

4. Our results are consistent with those of similar studies of larger streams in the high‐Arctic region. Based on our short‐term experiment, increased inputs of nutrients into these ecosystems, whether caused by climate change or more local disturbance, are likely to have profound ecological consequences. Longer‐term effects of enrichment, and their interaction with other components of future change in climate or land use, are more difficult to assess.