bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbonyl sulfide and carbon disulfide: Large‐scale distributions over the western Pacific and emissions from Asia during TRACE‐P
Authors: Blake Nicola J. , Streets David G. , Woo Jung‐Hun , Simpson Isobel J. , Green Jonathan , Meinardi Simone , Kita Kazuyuki , Atlas Elliot , Fuelberg Henry E. , Sachse Glen , Avery Melody A. , Vay Stephanie A. , Talbot Robert W. , Dibb Jack E. , Bandy Alan R. , Thornton Donald C. , Rowland F. Sherwood , Blake Donald R.
Published: June 2004

An extensive set of carbonyl sulfide (OCS) and carbon disulfide (CS2) observations were made as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE‐P) project, which took place in the early spring 2001. TRACE‐P sampling focused on the western Pacific region but in total included the geographic region 110°E to 290°E longitude, 5°N to 50°N latitude, and 0–12 km altitude. Substantial OCS and CS2 enhancements were observed for a great many air masses of Chinese and Japanese origin during TRACE‐P. Over the western Pacific, mean mixing ratios of long‐lived OCS and shorter‐lived CS2 showed a gradual decrease by about 10% and a factor of 5–10, respectively, from the surface to 8–10 km altitude, presumably because land‐based sources dominated their distribution during February through April 2001. The highest mean OCS and CS2 levels (580 and 20 pptv, respectively, based on 2.5° × 2.5° latitude bins) were observed below 2 km near the coast of Asia, at latitudes between 25°N and 35°N, where urban Asian outflow was strongest. Ratios of OCS versus CO for continental SE Asia were much lower compared to Chinese and Japanese signatures and were strongly associated with biomass burning/biofuel emissions. We present a new inventory of anthropogenic Asian emissions (including biomass burning) for OCS and CS2 and compare it to emission estimates based on regional relationships of OCS and CS2 to CO and CO2. The OCS and CS2 results for the two methods compare well for continental SE Asia and Japan plus Korea and also for Chinese CS2 emissions. However, it appears that the inventory underestimates Chinese emissions of OCS by about 30–100%. This difference may be related to the fact that we did not include natural sources such as wetland emissions in our inventory, although the contributions from such sources are believed to be at a seasonal low during the study period. Uncertainties in OCS emissions from Chinese coal burning, which are poorly characterized, likely contribute to the discrepancy.
Subauroral electric fields and magnetospheric convection during the April, 2002 geomagnetic storms
Authors: Anderson P. C.
Published: June 2004

We analyze the ionospheric electric fields during the geomagnetic storms of April, 2002 using data from the DMSP satellites. The subauroral potential drop (ΦSA) in the evening sector exceeded 60 kV at times and was often a substantial fraction of total cross‐polar‐cap potential drop (ΦPC). At storm commencement, the subauroral electric field penetration moved rapidly equatorward reaching the lowest magnetic latitude well before the end of the storms' main phases. ΦPC and ΦSA were correlated well with AE with no time delay. However, the correlations of ΦPC and ΦSA with Dst occurred with significant time delays, about an hour for ΦPC and longer for ΦSA. The largest values of ΦPC were seen near the end of the storm main phases while the largest values of ΦSA were seen well into the recovery phases. The results of this study have important implications on models attempting to describe the dynamics of the plasmasphere, the inner magnetosphere and the ring current.
Further Investigation of Linkage Disequilibrium SNPs and their Ability to Identify Associated Susceptibility Loci
Authors: North B. V. , Curtis D. , Martin E. R. , Lai E. H. , Roses A. D. , Sham P. C.
Published: June 2004

There is currently considerable interest in the use of single‐nucleotide polymorphisms (SNPs) to map disease susceptibility genes. The success of this method will depend on a number of factors including the strength of linkage disequilibrium (LD) between marker and disease loci. We used a data set of SNP genotypings in the region of the APOE disease susceptibility locus to investigate the likely usefulness of SNPs in case‐control studies. Using the estimated haplotype structure surrounding and including the APOE locus, and assuming a codominant disease model, we treated each SNP in turn as if it were a disease susceptibility locus and obtained, for each disease locus and markers, the expected likelihood ratio test (LRT) to assess disease association.We were particularly interested in the power to detect association with the susceptibility polymorphism itself, the power of nearby markers to detect association, and the ability to distinguish between the susceptibility polymorphism and marker loci also showing association. We found that the expected LRT depended critically on disease allele frequencies. For disease loci with a reasonably common allele we were usually able to detect association. However, for only a subset of markers in the close neighbourhood of the disease locus was association detectable. In these cases we were usually, but not always, able to distinguish the disease locus from nearby associated marker loci. For some disease loci, no other loci demonstrated detectable association with the disease phenotype. We conclude that one may need to use very dense SNP maps in order to avoid overlooking polymorphisms affecting susceptibility to a common phenotype.
Ancestral Founder Mutation of the Nude (FOXN1) Gene in Congenital Severe Combined Immunodeficiency Associated with Alopecia in Southern Italy Population
Authors: Adriani M. , Martinez‐Mir A. , Fusco F. , Busiello R. , Frank J. , Telese S. , Matrecano E. , Ursini M. V. , Christiano A. M. , Pignata C.
Published: June 2004

Genetic alterations of the FOXN1 transcription factor, selectively expressed in thymic epithelia and skin, are responsible in both mice and humans for the Nude/SCID phenotype. The first described human FOXN1 mutation was a C792T transition in exon 5 resulting in the nonsense mutation R255X, and was detected in two probands originated from a small community in southern Italy. In this community, four additional children affected with congenital alopecia died in early childhood because of severe infections. In this study, we report on the screening for this mutation in 30% of the village population. This analysis led us to identify 55 heterozygous carriers (6.52%) of the R255X mutation out of 843 inhabitants screened. A genealogical study revealed that these subjects, belonging to 39 families, were linked in an extended 7‐generational pedigree comprising 483 individuals. Through the archival database a single ancestral couple, born at the beginning of the 19th century, was identified. To confirm the ancestral origin of the mutation we genotyped two microsatellite markers, D17S2187 and D17S1880, flanking the FOXN1 gene on chromosome 17. The three haplotypes identified, 3/R255X/3, 3/R255X/2 and 3/R255X/1, are consistent with a single ancestral origin for the mutation R255X.
Mitochondrial DNA and Y‐Chromosome Variation in the Caucasus
Authors: Nasidze I. , Ling E. Y. S. , Quinque D. , Dupanloup I. , Cordaux R. , Rychkov S. , Naumova O. , Zhukova O. , Sarraf‐Zadegan N. , Naderi G. A. , Asgary S. , Sardas S. , Farhud D. D. , Sarkisian T. , Asadov C. , Kerimov A. , Stoneking M.
Published: June 2004

We have analyzed mtDNA HVI sequences and Y chromosome haplogroups based on 11 binary markers in 371 individuals, from 11 populations in the Caucasus and the neighbouring countries of Turkey and Iran. Y chromosome haplogroup diversity in the Caucasus was almost as high as in Central Asia and the Near East, and significantly higher than in Europe. More than 27% of the variance in Y‐haplogroups can be attributed to differences between populations, whereas mtDNA showed much lower heterogeneity between populations (less then 5%), suggesting a strong influence of patrilocal social structure. Several groups from the highland region of the Caucasus exhibited low diversity and high differentiation for either or both genetic systems, reflecting enhanced genetic drift in these small, isolated populations. Overall, the Caucasus groups showed greater similarity with West Asian than with European groups for both genetic systems, although this similarity was much more pronounced for the Y chromosome than for mtDNA, suggesting that male‐mediated migrations from West Asia have influenced the genetic structure of Caucasus populations.
Mitochondrial DNA Heterogeneity in Tunisian Berbers
Authors: Fadhlaoui‐Zid K. , Plaza S. , Calafell F. , Ben Amor M. , Comas D. , Bennamar A. , Gaaied El
Published: June 2004

Berbers live in groups scattered across North Africa whose origins and genetic relationships with their neighbours are not well established. The first hypervariable segment of the mitochondrial DNA (mtDNA) control region was sequenced in a total of 155 individuals from three Tunisian Berber groups and compared to other North Africans. The mtDNA lineages found belong to a common set of mtDNA haplogroups already described in North Africa. Besides the autochthonous North African U6 haplogroup, a group of L3 lineages characterized by the transition at position 16041 seems to be restricted to North Africans, suggesting that an expansion of this group of lineages took place around 10500 years ago in North Africa, and spread to neighbouring populations. Principal components and the coordinate analyses show that some Berber groups (the Tuareg, the Mozabite, and the Chenini‐Douiret) are outliers within the North African genetic landscape. This outlier position is consistent with an isolation process followed by genetic drift in haplotype frequencies, and with the high heterogeneity displayed by Berbers compared to Arab samples as shown in the AMOVA. Despite this Berber heterogeneity, no significant differences were found between Berber and Arab samples, suggesting that the Arabization was mainly a cultural process rather than a demographic replacement.
The Genetic Basis for Sex Differences in Human Behaviour: Role of the Sex Chromosomes
Authors: Craig Ian W. , Harper Emma , Loat Caroline S.
Published: June 2004

The nature of the mechanisms underlying observed sex differences in human behaviour continues to be debated. This review concentrates on the thesis that genes on the sex chromosomes other than those directly controlling sex determination, and whose functions are, at least in part, independent from hormonal influences, play a significant role in determining gender differences in behaviour. To provide an adequate basis for examining this issue, the current understanding of the nature of sex determination, differences in behaviour and the influences of sex hormones are evaluated. The possible contribution to behavioural differences of those X‐linked genes which escape inactivation, or which may be subjected to imprinting, is discussed. The review concludes with a summary of the genetic basis for two sexually disparate types of behaviour.
Modification of the erythroid transcription factor GATA-1 by SUMO-1
Authors: Collavin Licio , Gostissa Monica , Avolio Fabio , Secco Paola , Ronchi Antonella , Santoro Claudio , Del Sal Giannino
Published: June 2004

The activity of transcription factors is tightly modulated by posttranslational modifications affecting stability, localization, and protein–protein interactions. Conjugation to SUMO is a reversible posttranslational modification that has been shown to regulate important transcription factors involved in cell proliferation, differentiation, and tumor suppression. Here, we demonstrate that the erythroid transcription factor GATA-1 is sumoylated
in vitro
and
in vivo
and map the single lysine residue involved in SUMO-1 attachment. We show that the nuclear RING finger protein PIASy promotes sumoylation of GATA-1 and dramatically represses its transcriptional activity. We present evidence that a nonsumoylatable GATA-1 mutant is indistinguishable from the WT protein in its ability to transactivate a reporter gene in mammalian cells and in its ability to trigger endogenous globin expression in
Xenopus
explants. These observations open interesting questions about the biological role of this posttranslational modification of GATA-1.
CD4 on CD8+T cells directly enhances effector function and is a target for HIV infection
Authors: Kitchen Scott G. , Jones Nicole R. , LaForge Stuart , Whitmire Jason K. , Vu Bien-Aimee , Galic Zoran , Brooks David G. , Brown Stephen J. , Kitchen Christina M. R. , Zack Jerome A.
Published: June 2004

Costimulation of purified CD8+T lymphocytes inducesde novoexpression of CD4, suggesting a previously unrecognized function for this molecule in the immune response. Here, we report that the CD4 molecule plays a direct role in CD8+T cell function by modulating expression of IFN-γ and Fas ligand, two important CD8+T cell effector molecules. CD4 expression also allows infection of CD8 cells by HIV, which results in down-regulation of the CD4 molecule and impairs the induction of IFN-γ, Fas ligand, and the cytotoxic responses of activated CD8+T cells. Thus, the CD4 molecule plays a direct role in CD8 T cell function, and infection of these cells by HIV provides an additional reservoir for the virus and also may contribute to the immunodeficiency seen in HIV disease.
Hydrogen peroxide mediates plant root cell response to nutrient deprivation
Authors: Shin Ryoung , Schachtman Daniel P.
Published: June 2004

Potassium (K
+
) is an essential nutrient required by plants in large quantities, but changes in soil concentrations may limit K
+
acquisition by roots. It is not known how plant root cells sense or signal the changes that occur after the onset of K
+
deficiency. Changes in the kinetics of Rb
+
uptake in
Arabidopsis
roots occur within 6 h after K
+
deprivation. Reactive oxygen species (ROS) and ethylene increased when the plants were deprived of K
+
. ROS accumulated in a discrete region of roots that has been shown to be active in K
+
uptake and translocation. Suppression of an NADPH oxidase in
Arabidopsis
(
rhd2
), which is involved in ROS production, prevented the up-regulation of genes that are normally induced by K
+
deficiency, but the induction of high-affinity K
+
transport activity was unchanged. Application of H
2
O
2
restored the expression of genes induced by K
+
deficiency in
rhd2
and was also sufficient to induce high-affinity K
+
transport activity in roots grown under K
+
-sufficient conditions. ROS production is an early root response to K
+
deficiency that modulates gene expression and physiological changes in the kinetics of K
+
uptake.
Bardet–Biedl syndrome type 4 (BBS4)-null mice implicate Bbs4 in flagella formation but not global cilia assembly
Authors: Mykytyn Kirk , Mullins Robert F. , Andrews Michael , Chiang Annie P. , Swiderski Ruth E. , Yang Baoli , Braun Terry , Casavant Thomas , Stone Edwin M. , Sheffield Val C.
Published: June 2004

The functions of the proteins encoded by the Bardet–Biedl syndrome (BBS) genes are unknown. Mutations in these genes lead to the pleiotropic human disorder BBS, which is characterized by obesity, retinopathy, polydactyly, renal and cardiac malformations, learning disabilities, and hypogenitalism. Secondary features include diabetes mellitus and hypertension. Recently, it has been suggested that the BBS phenotypes are the result of a lack of cilia formation or function. In this study, we show that mice lacking the Bbs4 protein have major components of the human phenotype, including obesity and retinal degeneration. We show that Bbs4-null mice develop both motile and primary cilia, demonstrating that Bbs4 is not required for global cilia formation. Interestingly, male Bbs4-null mice do not form spermatozoa flagella, and BBS4 retinopathy involves apoptotic death of photoreceptors, the primary ciliated cells of the retina. These mutation data demonstrate a connection between the function of a BBS protein and cilia. To further evaluate an association between cilia and BBS, we performed homology comparisons of BBS proteins in model organisms and find that BBS proteins are specifically conserved in ciliated organisms.
Inhibition of influenza virus production in virus-infected mice by RNA interference
Authors: Ge Qing , Filip Lily , Bai Ailin , Nguyen Tam , Eisen Herman N. , Chen Jianzhu
Published: June 2004

Influenza A virus infection is a major source of morbidity and mortality worldwide. Because the effectiveness of existing vaccines and antiviral drugs is limited, development of new treatment modalities is needed. Here, we show that short interfering RNAs (siRNAs) specific for conserved regions of influenza virus genes can prevent and treat influenza virus infection in mice. Virus production in lungs of infected mice is reduced by siRNAs given either before or after initiating virus infection, by using slow i.v. administration of small volumes containing siRNAs in complexes with a polycation carrier. Similar effects also are observed when mice are given DNA vectors i.v. or intranasally, from which siRNA precursors can be transcribed. Development of delivery systems that may be compatible with human use demonstrates the potential utility of siRNAs for prophylaxis and therapy of influenza virus infections in humans.
Changing concentrations of CO, CH
4
, C
5
H
8
, CH
3
Br, CH
3
I, and dimethyl sulfide during the Southern Ocean Iron Enrichment Experiments
Authors: Wingenter Oliver W. , Haase Karl B. , Strutton Peter , Friederich Gernot , Meinardi Simone , Blake Donald R. , Rowland F. Sherwood
Published: June 2004

Oceanic iron (Fe) fertilization experiments have advanced the understanding of how Fe regulates biological productivity and air–sea carbon dioxide (CO
2
) exchange. However, little is known about the production and consumption of halocarbons and other gases as a result of Fe addition. Besides metabolizing inorganic carbon, marine microorganisms produce and consume many other trace gases. Several of these gases, which individually impact global climate, stratospheric ozone concentration, or local photochemistry, have not been previously quantified during an Fe-enrichment experiment. We describe results for selected dissolved trace gases including methane (CH
4
), isoprene (C
5
H
8
), methyl bromide (CH
3
Br), dimethyl sulfide, and oxygen (O
2
), which increased subsequent to Fe fertilization, and the associated decreases in concentrations of carbon monoxide (CO), methyl iodide (CH
3
I), and CO
2
observed during the Southern Ocean Iron Enrichment Experiments.
DNA axial rotation and the merge of oppositely supercoiled DNA domains in
Escherichia coli
: Effects of DNA bends
Authors: Stupina Vera A. , Wang James C.
Published: June 2004

We have examined the issue whether axial rotation of an intracellular DNA segment several thousand base pairs in length is associated with a large friction barrier against the merge of oppositely supercoiled DNA domains. The induction of a site-specific recombinase was used to form intracellular DNA rings bearing different numbers of transcription units, and it was found that DNA rings with a single
tetA
gene and no other transcription units does not become excessively negatively supercoiled in
Escherichia coli
cells lacking DNA topoisomerase I. Thus, whereas oppositely supercoiled domains are generated in a
tetA
-bearing DNA ring through anchoring of the tetA transcripts to cell membrane, these domains appear to readily merge by means of axial rotation of the DNA segment connecting them. The diffusional merge of these oppositely supercoiled domains is not significantly affected by the presence of bent sequences in the intervening DNA segment. Examination of the effects of adding more transcription units to the
tetA
-bearing ring suggests, however, that DNA bends stabilized by bound protein molecules may significantly impede this process inside
E. coli
, as suggested by previous
in vitro
studies [Leng, F. & McMacken, R. (2002)
Proc. Natl. Acad. Sci. USA
99, 9139–9144].
The linker-loop region ofEscherichia colichaperone Hsp31 functions as a gate that modulates high-affinity substrate binding at elevated temperatures
Authors: Sastry M. S. R. , Quigley Paulene M. , Hol Wim G. J. , Baneyx François
Published: June 2004

Precise control of substrate binding and release is essential for molecular chaperones to exert their protective function in times of stress. The mechanisms used are diverse and have been difficult to unravel.Escherichia coliheat-shock protein 31 (Hsp31) is a recent addition to the known complement of eubacterial chaperones. Crystallographic studies have revealed the presence of a hydrophobic bowl at the Hsp31 dimer interface and shown that the linker region connecting the two structural domains within each subunit is disordered. Together with a neighboring flexible loop, the linker caps a hydrophobic area adjacent to the bowl. Using a collection of Hsp31 mutants, we show that although both bowl and linker-loop-shielded residues participate in substrate binding, the latter are critical for protein capture at high temperature. Linker immobilization via an artificial disulfide bridge abolishes chaperone activity at elevated temperatures by precluding exposure of the underlying hydrophobic domain. We conclude that Hsp31 uses its linker-loop region as a thermally activated gate to control nonnative protein annealing to a high-affinity substrate-binding site. This simple yet efficient strategy to capture partially folded proteins under heat-shock conditions may be shared by other folding modulators.
SV40 T antigen interacts with Nbs1 to disrupt DNA replication control
Authors: Wu Xiaohua , Avni Dror , Chiba Takuya , Yan Feng , Zhao Qiping , Lin Yafang , Heng Henry , Livingston David
Published: June 2004

Nijmegen breakage syndrome (NBS) is characterized by radiation hypersensitivity, chromosomal instability, and predisposition to cancer. Nbs1, the NBS protein, forms a tight complex with Mre11 and Rad50, and these interactions contribute to proper double-strand break repair. The simian virus 40 (SV40) oncoprotein, large T antigen (T), also interacts with Nbs1, and T-containing cells experience chromosomal hyperreplication in a manner dependent on T/Nbs1 complex formation. A substantial fraction of NBS-deficient fibroblasts reinitiate DNA replication in discrete regions, and wild-type Nbs1 corrects this defect. Similarly, synthesis of an N-terminal Nbs1 fragment induced DNA rereplication and tetraploidy, in NBS-deficient but not NBS-proficient cells. Moreover, SV40 origin-containing DNA hyperreplicated in T-containing NBS-deficient cells by comparison with T-containing, Nbs1-reconstituted derivatives. Thus, Nbs1 suppresses rereplication of cellular DNA and SV40 origin-containing replicons, and T targets Nbs1, thereby enhancing the yield of new SV40 genomes during viral DNA replication.
Mismatch repair-dependent G2 checkpoint induced by low doses of SN1 type methylating agents requires the ATR kinase
Authors: Stojic Lovorka , Mojas Nina , Cejka Petr , di Pietro Massimiliano , Ferrari Stefano , Marra Giancarlo , Jiricny Josef
Published: June 2004

SN1-type alkylating agents represent an important class of chemotherapeutics, but the molecular mechanisms underlying their cytotoxicity are unknown. Thus, although these substances modify predominantly purine nitrogen atoms, their toxicity appears to result from the processing of O6-methylguanine (6MeG)-containing mispairs by the mismatch repair (MMR) system, because cells with defective MMR are highly resistant to killing by these agents. In an attempt to understand the role of the MMR system in the molecular transactions underlying the toxicity of alkylating agents, we studied the response of human MMR-proficient and MMR-deficient cells to low concentrations of the prototypic methylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). We now show that MNNG treatment induced a cell cycle arrest that was absolutely dependent on functional MMR. Unusually, the cells arrested only in the second G2 phase after treatment. Downstream targets of both ATM (Ataxia telangiectasia mutated) and ATR (ATM and Rad3-related) kinases were modified, but only the ablation of ATR, or the inhibition of CHK1, attenuated the arrest. The checkpoint activation was accompanied by the formation of nuclear foci containing the signaling and repair proteins ATR, the S*/T*Q substrate, γ-H2AX, and replication protein A (RPA). The persistence of these foci implied that they may represent sites of irreparable damage.
It's not what you know, it's who you know
Authors: Broadbridge Adelina
Published: June 2004

Utilising a biographical methodological research methodology, this paper examines the career development of men and women managers within the retail environment. The findings utilising this research methodology revealed the relative importance of self promotion and other informal policies as opportunities or threats to individuals’ career development. This article explores how such informal processes manifest themselves in the career development of managers and reveals how men are more likely than women, albeit unconsciously, to report such informal processes as helping in their career development. The paper demonstrates how a biographical story telling approach can uncover rich qualitative data that would not otherwise be revealed by adopting a more quantitative methodological approach.
A decision tree approach for integrating small business assistance schemes
Authors: Temtime Zelealem T. , Chinyoka S.V. , Shunda J.P.W.
Published: June 2004

There is a general consensus among public policy makers, academics and researchers that entrepreneurship is a vital route to economic advancement for both developed and developing economies. As a result, a host of small business assistance programs are conducted by public, private and nonprofit organizations. Although the need for integrating these programs has always been a high priority on the national agenda for public policy and research in entrepreneurship, their implementation particularly in developing economies is characterized by fragmentation and lack of coordination. Small business assistance will be meaningful if they are designed in a holistic and systematic way and implemented with a view to achieve long term sustainable development. This paper offers a conceptual framework for designing an integrated model of small business assistance. The paper identifies the major characteristics of small firms and potential small business assistance programs, and presents a decision tree model that matches the characteristics of firms with appropriate assistance program(s). A case study of small business assistance programs in the Republic of Botswana was conducted to provide an empirical evidence of the need for an integrated design or model. Finally, conclusions, discussions and the implications of the model for policy makers, practitioners and further research are presented.
Analysis of the perceived degree of success of reform efforts: reform agents’ perceptions
Authors: Monavvarian Abbas
Published: June 2004

In this article, the perceptions of reform agents regarding the degree of success of different aspects of the reform program during the period of the Iranian second five‐year plan (1995‐2000), by using a questionnaire, is analyzed. To supplement the findings of the questionnaire, the responses of the subjects of the interviews are subject to content analysis. Comparison of the findings of the adopted survey instruments is used to achieve to a conclusion on the extent of success of the reform program. Although the overall results indicate that the reform program was not perceived as having been as successful as expected, however, a minority of the interviewees (25 percent) argued that the program was successful at a reasonable level. Lack of participation of key groups in design and implementation of the program, inconsistency between the reform objectives and the missions of line organizations, diversity of reform agencies, and lack of enthusiasm and commitment of middle and top level managers were among the perceived barriers to success of reform program.
Life‐history variation among local populations of Atlantic cod from the Norwegian Skagerrak coast
Authors: Olsen E. M. , Knutsen H. , Gjøsæter J. , Jorde P. E. , Knutsen J. A. , Stenseth N. C.
Published: June 2004

Small‐scale spatial variation in life history was found among genetically distinct local populations of Atlantic cod Gadus morhua from the Norwegian Skagerrak coast. Among populations, age at 50% maturity varied from 2·6 to 3·8 years, total (LT) length at 50% maturity from 35 to 60 cm, annual survival from 33 to 64%, mean LT at age 4 years from 43 to 63 cm, and mean backcalculated LT at age 1 year from 8 to 12 cm.
The biology of the bigeye grenadier at South Georgia
Authors: Morley S. A. , Mulvey T. , Dickson J. , Belchier M.
Published: June 2004

The biology of the bigeye grenadierMacrourus holotrachyscaught as by‐catch in the Patagonian toothfishDissostichus eleginoideslongline fishery conducted around South Georgia was investigated to improve data available for fisheries management. Age estimates suggest thatM. holotrachysis a moderately slow growing species (K = 0·10), reaching ages of >30 years and attaining total lengths (LT) >80 cm (L∞ = 33). The size at which 50% of females had started to mature (Lint50) forM. holotrachyswas 21 cm pre‐anal length (LPA) and occurred atc. 9 years old. Estimates of natural mortality and Pauly's growth performance index were found to be low (M = 0·09 and Φ = 2·82 respectively). Gonad maturity stage was described from macroscopic and histological investigation. Mature ovaries had oocytes at all developmental stages with between 22 and 55% likely to be spawned each year. Absolute fecundity ranged from 22 000 to 260 000 eggs and was positively correlated with both pre‐anal length and mass. A highly skewed sex ratio of 32 : 1, females : males, was found for specimens caught by longlines but not for a small sample of shallower trawl‐caught specimens. It is suggested that females are far more susceptible to longline capture than males.Macrourus holotrachysis a bentho‐pelagic predator and scavenger that feeds on a wide range of fishes and invertebrates. The fish are long lived, slow‐growing species typical of deep‐water grenadiers; fisheries management strategies should reflect their probable susceptibility to overfishing.
Ultrastructural observations of euspermatozoa and paraspermatozoa in a copulatory cottoid fish Blepsias cirrhosus
Authors: Hayakawa Y. , Munehara H.
Published: June 2004

Euspermatozoa and paraspermatozoa of a copulatory (internal insemination with external sperm transfer) cottoid fish Blepsias cirrhosus were observed ultrastructurally. Euspermatozoa of B. cirrhosus consisted of an acrosome‐less, thin, disk‐like sperm head (1·6‐2·0 μm in length and 1·3‐1·6 μm in width), a long middle piece, and a long flagellum (c. 30 μm). Aberrant spermatids, which were rich in cytoplasm and possessed two nuclei, occurred in testicular lobules. They were also observed in semen and were round (5·0‐5·3 μm in diameter) and biflagellate, suggesting that they are released along with euspermatozoa at ejaculation. The nuclei of aberrant spermatids developed into masses of highly electron‐dense globules. Judging from their form, nuclear condition, and connection with normal spermatids by intercellular bridges during spermiogenesis, aberrant spermatids of B. cirrhosus are considered hyperpyrenic paraspermatozoa formed by incomplete cytokinesis at the second meiotic division.
Structural and ultrastructural comparison of photophores of two species of deep‐sea fishes: Argyropelecus hemigymnus and Maurolicus muelleri
Authors: Cavallaro M. , Mammola C. L. , Verdiglione R.
Published: June 2004

The structure of the photophores (luminous organs) of two species of deep‐sea fishes from the Strait of Messina, Argyropelecus hemigymnus and Maurolicus muelleri, was examined. Although significant structural differences were identified between species, especially in photophore organization and distribution, ultrastructural comparisons indicated a marked similarity between them. The photocytes exhibited numerous secretory granules, of different electron density, embedded in an extremely developed rough endoplasmic reticulum. Numerous mitochondria were observed among the secretory granules. The lens appeared to be composed of tightly contiguous polyhedral cells. The reflector was made up of cells rich in guanine crystals embedded in an amorphous matrix and appeared to be surrounded by a layer of connective tissue full of melanocytes. Ventrally, every photophore was delimited by a thick cellular layer called the ‘gelatinous layer’ with dioptric properties. The results confirm that even though A. hemigymnus and M. muelleri differ widely phylogenetically, they exhibit adaptive convergence, involving similar morphology and physiology in these luminous structures.
Short‐term freshwater exposure benefits sea lice‐infected Atlantic salmon
Authors: Wagner G. N. , Mckinley R. S. , Bjørn P. A. , Finstad B.
Published: June 2004

Atlantic salmon Salmo salar were infected with sea lice Lepeophtheirus salmonis(0·08 ± 0·007 sea lice g−1) over a period of 4 h. Both infected and non‐infected fish were swim tested in sea water (SW) and fresh water (FW). The ventral aorta of each fish was fitted with a Doppler cuff in order to measure cardiac output, stroke volume and heart rate during swim testing. Blood samples were taken at rest and after exercise. Critical swimming speed of infected fish in SW (2·14 ± 0·08 body lengths, bl s−1) was significantly lower (P < 0·05) than infected fish switched to FW (2·81 ± 0·08 bl s−1) and non‐infected fish in SW (2·42 ± 0·04 bl s−1) and FW (2·61 ± 0·08 bl s−1). Cardiac and blood results indicated infected fish exposed to FW did experience stress, but relief from osmotic and ionic distress probably reduces energy expenditure, allowing the increase in performance. As the performance of sea lice‐infected fish improved upon transfer to FW, it is likely that heavily infected salmonids do return to FW to restore compromised osmotic and ionic balance, and remove sea lice in the process.
Age effects on diel activity patterns of juvenile Atlantic salmon: parr are more nocturnal than young‐of‐the‐year
Authors: Imre I. , Boisclair D.
Published: June 2004

In the summer Atlantic salmonSalmo salarparr were predominantly active at night, while young‐of‐the‐year were equally active during day and at night. These findings are consistent with the prediction that larger animals should be less willing to risk predation for a certain increase in size than smaller animals.
Rhythmic pattern of growth and nutrient retention in response to feeding time in the rainbow trout
Authors: Bolliet V. , Jarry M. , Boujard T.
Published: June 2004

The effect of six different feeding times was tested on feed intake, growth performance, proximate body composition and nutrient retention in the rainbow trout Oncorhynchus mykiss. Using a non‐linear regression model, a significant rhythmic pattern over a 24 h period was observed for feed gain ratio and nutrient retention responses to feeding time. Specific growth rate and protein growth rate responses were also rhythmic but the trends were not significant. There was no clear effect of feeding time on feed intake and proximate body composition. The study suggested that feed intake, at least under the experimental conditions encountered, was synchronized to feeding time while some physiological rhythms involved in nutrient metabolism were probably synchronized to photoperiod.
Otolith‐based analysis of survival and size‐selective mortality of stocked 0+ year pike related to time of stocking
Authors: Grønkjær P. , Skov C. , Berg S.
Published: June 2004

The effect of time of stocking on the extent and source of mortality in 0+ year pike Esox lucius was investigated in a lake (20 ha) and a drainable pond (0·5 ha) using pike with alizarin marked otoliths. The results indicated that pike stocked late relative to the recruitment of native 0+ year pike fell victim to cannibalism from these larger individuals. This resulted in very low survival through the first growing season (<2%). Pike stocked early in the season exhibited significantly higher survival (>12%). Analyses of the size distribution of the alizarin marks from these fish revealed that the largest 0+ year pike exhibited by a factor of 3·3, higher survival than the average 0+ year pike in the lake. In order for large 0+ year pike to exhibit such high relative fitness a minimum of 69·7% of the original population must suffer size dependent mortality. In the pond the survival of the largest pike was by a factor of 4·2 higher than the average pike, and the corresponding size dependent mortality was 76·4%. The substantial size‐dependent mortality was most probably due to intra‐cohort cannibalism or habitat segregation between large and small 0+ year pike that exposes the small pike to predatory fishes in the open lake. Cannibalism exerts a major influence on the survival of 0+ year pike post‐stocking although the magnitude and origin differ in relation to stocking time.
Sperm traits in relation to male quality in colonial spawning bluegill
Authors: Casselman S. J. , Montgomerie R.
Published: June 2004

Sperm traits (morphology, motility and concentration within ejaculates) and various correlates of male quality (age, body condition, spawning location and timing) were studied in bluegill Lepomis macrochirus, breeding in both the interior and periphery of six colonies in Lake Opinicon, Ontario, Canada. Sperm traits varied significantly more among than within males suggesting that some aspect of male phenotype might influence sperm morphology and behaviour. No measures of male body condition or size were correlated with any sperm or ejaculate traits, when controlling statistically for confounding variables. Sperm swimming speed increased significantly with male age and varied significantly among spawning bouts (controlling for sperm tail length) suggesting that some unknown aspects of male quality might influence the fertilization capacity of spermatozoa. Sperm concentration in ejaculates was significantly higher in males nesting in the interior rather than the periphery of a colony suggesting that those males might also have higher fertilization capacity correlated with their superior dominance status or the lower risk of sperm competition. Thus, older males nesting in the interior of a colony during the first spawning bout of the season are expected to be the best sperm competitors in this population, but the physiological reasons for this increased fertilization capacity remain unknown.
Fish density and size alter Pacific halibut feeding: implications for stock assessment
Authors: Stoner A. W. , Ottmar M. L.
Published: June 2004

Laboratory experiments were conducted with Pacific halibut Hippoglossus stenolepis to test the hypothesis that responsiveness to food cues is density‐ and size‐ dependent. Tanks holding one, two and four fish were video‐taped continuously before and after introduction of an olfactory cue and whole baits (squid). Pre‐cue indices of activity did not vary with fish density. After olfactory stimulation, per capita activity was directly related to density, with no significant increase in activity by single fish. Numbers of baits located, attacked and consumed were directly related to fish density, and average times to first attack varied from 12 s in groups of four fish to >15 min in single fish. The latency period between location and attack decreased significantly with fish density. When large (43–55 cm, total length, LT) and small (31–38 cm LT) Pacific halibut were tested together in pairs and groups of four fish, small individuals located baits first in 61% of the trials. Large fish, however, consumed all of the baits (except one) in trials where both large and small fish responded. Social facilitation in Pacific halibut feeding will result in a non‐linear relationship between catch per unit effort and population density, and the size composition of fish captured may be influenced by interference competition.
Adult anopheline ecology and malaria transmission in irrigated areas of South Punjab, Pakistan
Authors: Herrel N. , Amerasinghe F. P. , Ensink J. , Mukhtar M. , Van Der Hoek W. , Konradsen F.
Published: June 2004

Abstract.  Surface irrigation in the Punjab province of Pakistan has been carried out on a large scale since the development of the Indus Basin Irrigation System in the late 19th century. The objective of our study was to understand how the population dynamics of adult anopheline mosquitoes (Diptera: Culicidae) could be related to malaria transmission in rural areas with intensive irrigation and a history of malaria epidemics. In this paper we present our observations from three villages located along an irrigation canal in South Punjab. The study was carried out from 1 April 1999 to 31 March 2000. Mosquitoes were collected from bedrooms using the pyrethroid spraycatch method and from vegetation and animal sheds using backpack aspirators. Overall, Anopheles subpictus Grassi sensu lato predominated (55.6%), followed by An. stephensi Liston s.l. (41.4%), An. culicifacies Giles s.l. (2.0%), An. pulcherrimus Theobald (1.0%) and An. peditaeniatus Leicester (0.1%). Most mosquitoes (98.8%) were collected from indoor resting‐sites whereas collections from potential resting‐sites outdoors accounted for only 1.2% of total anopheline densities, confirming the endophilic behaviour of anophelines in Pakistan. Anopheles stephensi, An. culicifacies and An. subpictus populations peaked in August, September and October, respectively. High temperatures and low rainfall negatively affected seasonal abundance in our area. There were interesting differences in anopheline fauna between villages, with An. culicifacies occurring almost exclusively in the village at the head of the irrigation canal, where waterlogged and irrigated fields prevailed. Monthly house‐to‐house fever surveys showed that malaria transmission remained low with an overall slide positivity rate of 2.4% and all cases were due to infection with Plasmodium vivax. The most plausible explanation for low transmission in our study area seems to be the low density of Pakistan's primary malaria vector, An. culicifacies. The role of other species such as An. stephensi is not clear. Our observations indicate that, in South Punjab, irrigation‐related sites support the breeding of anopheline mosquitoes, including the vectors of malaria. As our study was carried out during a year with exceptionally hot and dry climatic conditions, densities and longevity of mosquitoes would probably be higher in other years and could result in more significant malaria transmission than we observed. To assess the overall importance of irrigation‐related sites in the epidemiology of malaria in the Punjab, more studies are needed to compare irrigated and non‐irrigated areas.
Feeding and survival of the malaria vector Anopheles gambiae on plants growing in Kenya
Authors: Impoinvil D. E. , Kongere J. O. , Foster W. A. , Njiru B. N. , Killeen G. F. , Githure J. I. , Beier J. C. , Hassanali A. , Knols B. G. J.
Published: June 2004

Abstract.  The propensity of the malaria vector mosquito Anopheles gambiae Giles (Diptera: Culicidae) to ingest sugars from various plants, and subsequent survival rates, were assessed with laboratory‐reared males and females offered eight species of plants commonly cultivated and/or growing wild in western Kenya. In cages (no‐choice bioassay), mosquitoes given the opportunity to feed on castorbean (Ricinus communis L.) had the longest survival times (mean and median survival time of 6.99 ± 0.23 and 5.67 ± 0.17 days, respectively), comparable to mosquitoes given 6% glucose (mean and median survival time of 8.70 ± 0.23 and 6.67 ± 0.33 days, respectively). Survival rates of An. gambiae were low on the other plants, comparable to mosquitoes given only water. Three plants: sweet potato (Ipomoea batatas L.), wild sage (Lantana camara L.) and castorbean provided levels of sugar ingestion by both sexes of An. gambiae detectable using the cold anthrone method, showing a positive correlation between median survival and sugar consumption (Spearman rank correlation coefficient = 0.905, P < 0.0001). Equal numbers of males and females were released in an enclosed semi‐field screenhouse system containing a range of local plants, but no host for blood, and allowed to feed ad libitum: 6.7 ± 0.5% (11/64) of those recaptured were found to contain detectable fructose (all females). Common plants are clearly a viable source of nutrition for adult female An. gambiae, as well as males, and may constitute and important resource for this important malaria vector.
Acaricidal activity of aqueous extracts of camomile flowers, Matricaria chamomilla, against the mite Psoroptes cuniculi
Authors: Macchioni F. , Perrucci S. , Cecchi F. , Cioni P. L. , Morelli I. , Pampiglione S.
Published: June 2004

Abstract.  Arcaricidal properties of decoctions, infusions and macerates of dried flower heads of camomile, Matricaria chamomilla L. (Asterales: Asteraceae) were tested in vitro against the mite Psoroptes cuniculi Delafond (Parasitiformes: Psoroptidae). This mite species is responsible for otoacariasis in domestic animals. Mites were exposed to the extracts for 24, 48 or 72 h. All the extracts tested showed highly significant acaricidal activity when compared with controls. Among them, a decoction of 10% was the only formulation which gave 100% activity at all the three observations times.
Horseflies of Jordan
Authors: Al‐Talafha H. , Amr Z. S. , Baker M. Abu , Bader A. Katbeh
Published: June 2004

Abstract.  The horsefly (Diptera: Tabanidae) fauna of Jordan consists of 21 species belonging to seven genera. The present study adds 17 new records to this little‐known group of haematophagous insects. Most of the new records were collected from several localities within the Jordan Valley. These new records are Chrysops flavipes Meigen, Atylotus farinosus (Szilády), Dasyrhamphis umbrinus (Meigen), Haematopota coronata Austen, Hybomitra decora (Loew), Hybomitra mendica (Villeneuve), Tabanus accensus Austen, T. albifacies Loew, T. bifarius Loew, T. darimonti Leclercq, T. laetetinctus Becker, T. leleani Austen, T. pallidipes Austen, T. regularis Jaennicke, T. rupinae Austen, T. sufis Jaennicke and Therioplectes tunicatus (Szilády). Tabanus albifacies and T. sufis were the most common species collected by hand nets (19.85% and 17.73%, respectively) and D. umbrinus, Haematopota minuscula Austen, and Haematopota coronata were the least common species (0.12% for each). Zoogeographical analysis of the recorded species showed that 12 species are of Mediterranean origin, four are of Afrotropical origin, two of European origin and at least three species can be considered as endemic to the Middle East.