The isolation of Atlantic cod, Gadus morhua (Gadiformes), populations in Northern Meromictic lakes—A recurrent arctic phenomenon

Although it has previously been considered to be a rare phenomenon, this paper provides evidence of eight occurrences of Atlantic cod in northern coastal saline lakes in Arctic Canada, Greenland, Norway, and Russia. Historic and current habitat features that are necessary for Atlantic cod to colonize and persist in Arctic meromictic lakes are discussed. Data analyses confirm that the persistence of Atlantic cod in Arctic lakes is a recurrent phenomenon, and these populations represent an important component of intraspecific biodiversity. Published in Russian in Voprosy Ikhtiologii, 2008, Vol. 48, No. 2, pp. 179–190. The text was submitted by the authors in English.     

The abundance and patterns of the egg and larval spatial distribution of Eastern Baltic cod Gadus morhua callarias (Gadidae) in 1931–1996

According to ichthyoplankton surveys of AtlantNIRO and published sources, the data on abundance of eggs and larvae of eastern Baltic cod Gadus morhua callarias at different spawning grounds of the Baltic Sea in 1931–1938, 1949–1956, and 1991–1996 are considered. We show that a similar type of spatial distribution of eggs and larvae of cod with localization of the greatest amount of its early ontogenetic stages in the Bornholm Basin in the southwest of the sea was observed in the 1930s and 1990s. The extension of the area of distribution was accompanied by an increase in the numbers of eggs and larvae of cod in all areas of the sea, and its decline was followed by a decrease in numbers, in the first turn, at northeastern spawning grounds in the Gotland Basin. The period of high numbers of eggs in 1949–1956 coincided with the century maximum of salinity of the near-bottom water layer.     

The occurrence of some metazoan parasites of Atlantic cod, Gadus morhua L., in relation to age and sex of the host in Balsfjord (70°N), North Norway

Age and sex differences in the occurrence of some metazoan parasites were investigated in 243 cod (Gadus morhua L.) from Balsfjord, a subarctic fjord in northern Norway. Thirteen species of parasite were studied, comprising seven nematodes, three parasitic copepods, one acanthocephalan, one cestode and one digenean. The nematode Anisakis simplex showed significant increases in both prevalence and mean abundance with host age, while the digenean Hemiurus levinseni showed a significant increase in mean abundance with age. The increases probably result from a long parasite life-span for A. simplex and changes in the feeding pattern of cod with age for H. levinseni. Prevalence of the nematode Contracaecum sp. and mean abundance of the acanthocephalan Echinorhynchus gadi were significantly higher in male than in female cod, whereas mean abundance of H. levinseni was significantly higher in female cod. These results suggest that there may be differences in feeding behaviour between male and female cod in Balsfjord. Accepted: 14 November 1999     

Genetic and morphological variation in Echinorhynchus gadi Zoega in Müller, 1776 (Acanthocephala: Echinorhynchidae) from Atlantic cod Gadus morhua L

Previous studies have shown considerable variability in morphological features and the existence of genetically distinct sibling species in the acanthocephalan Echinorhynchus gadi Zoega in Müller, 1776. The aim of the present study was to follow up and extend those earlier studies by using a combination of DNA analysis and morphometrics to investigate differences between samples of E. gadi from Atlantic cod Gadus morhua L. caught at five fishing grounds in the Baltic Sea and three in different parts of the North Atlantic. Twelve morphological features were measured in 431 specimens of E. gadi, 99 individuals were studied by polymerase chain reaction-restriction fragment length polymorphosm (PCR-RFLP), and selected PCR products were sequenced. The molecular analyses showed the nucleotide sequences of E. gadi rDNA from cod caught at all the sampling sites to be identical. The comparative morphological study, in contrast, revealed significant differences between samples of E. gadi from different sampling sites and showed the separation of E. gadi into two groups corresponding approximately to the systematic classification of cod into the two subspecies, Atlantic G. morhua morhua and Baltic G. morhua callarias. The E. gadi infrapopulation size had a significant effect on some of the morphological features. The results are discussed in relation to cod population biology, the hydrography of the study area and the history of the Baltic Sea formation.     

The significance of chelae in the agonistic behaviour of the white‐clawed crayfish,a Ustropotamobius pallipes

As in other benthic decapods, crayfish have chelae that are important for intra‐specific agonistic encounters. In Austropotamobius pallipes, scars and mutilations are present mostly on the chelae, these being the main targets of agonistic contacts. Because males participate in more aggressive interactions than females do and compete with other males for acquiring females in escalating contests, selection for large chelae should be stronger in males. Thus, in A. pallipes (i) chelae are longer, wider and higher in males than in females; (ii) chelar size in males increases allometrically with cephalothorax length; (iii) male specimens are more often deprived of at least one cheliped and (iv) large males have the highest frequency of scars. Males with one regenerated cheliped, when opposed to a competitor with both large chelipeds, display the same motivation to fight, but perform less chelae threat displays than normal crayfish and immediately get a lower hierarchical rank. In these contests, Resource Holding Potential (= chelar size) is highly different between the crayfish and the information of this asymmetry is correctly transferred between the two opponents.     

Assessment of the diets of cod Gadus morhua and whiting Merlangius merlangus juveniles in a frontal region close to the Norwegian Trench: co‐existence or competition?

Over 200 pelagic juvenile cod Gadus morhua and whiting Merlangius merlangus were sampled in spring 2001 at stations inside and outside a frontal region close to the Norwegian Trench, and their stomach contents analysed in the context of zooplankton samples taken at the same time and same locations. Merlangius merlangus juveniles appeared to feed on a diverse zooplankton community, whereas G. morhua juveniles appeared to preferentially select Pseudocalanus elongatus, even though these prey items were not the dominant component of the prey community. The results suggest that during the pelagic juvenile stage, M. merlangus and G. morhua are direct competitors for zooplanktonic prey. In addition, because M. merlangus are more opportunistic, they may be more tolerant to changes in the species composition of the prey community, and therefore out‐compete G. morhua juveniles at times of low preferred prey abundance or under changing environmental conditions.     

The evolution of infertility: does hatching rate in birds coevolve with female polyandry?

Natural levels of infertility in many taxa are often remarkably high, amounting to a considerable fitness cost which one expects to be minimized by natural selection. Several mechanisms have been proposed as potential causes of infertility, including inbreeding depression, genetic incompatibilities and selfish genetic elements. Infertility may also be an inherent result of conflict over fertilization between the sexes in polyandrous species, either because too many sperm enter the egg or because of over‐efficient barriers to such polyspermic fertilizations. We generated phylogenetic independent contrasts to examine the variation in hatching success for a maximum of 58 species of birds in relation to two measures of female polyandry. Hatching success varied enormously across species (range: 61–100%), with a mean of 12% of eggs failing to hatch, but was not related to either the rate of extrapair paternity or to relative testes size. Thus, the causes of this significant fitness cost remains unclear and merits further examination by evolutionary biologists.     

1H, 13C and 15N resonance assignments and second structure information of Gad m 1: a β-parvalbumin allergen from Atlantic cod (Gadus morhua)

Gad m 1 is the major allergen from Atlantic cod. It belongs to β-parvalbumin protein family and is characterized by the presence of two calcium-binding sites so called EF-hand motifs. β-Parvalbumins such as Gad m 1 are the most important fish allergens and their high cross-reactivity is the cause of the observed polysensitization to various fish species in allergic patients. Despite extensive efforts, the complete elucidation of β-parvalbumin-IgE complexes has not been achieved yet. Allergen structural studies are essential for the development of novel immunotherapy strategies, including vaccination with hypoallergenic derivatives and chimeric molecules. Here, we report for the first time the NMR study of a β-parvalbumin: Gad m 1. This report includes: ¹H, ¹³C and ¹⁵N resonance assignments of Gad m 1 as well as the second structure information based on the ¹³C chemical shifts.     

The significance of abrupt transitions in Lineweaver–Burk plots with particular reference to glutamate dehydrogenase. Negative and positive co-operativity in catalytic rate constants

1. Lineweaver-Burk plots for glutamate dehydrogenase, glucose 6-phosphate dehydrogenase and several other enzymes show one or more abrupt transitions between apparently linear sections. These transitions correspond to abrupt increases in the apparent K(m) and V(max.) with increasing concentration of the varied substrate. 2. The generalized reciprocal initial-rate equation for a multi-site enzyme requires several restrictions to be put on it in order to generate such plots. These mathematical conditions are explored. 3. It is shown that the effective omission of a term in the denominator of the reciprocal initial-rate equation represents a minimal requirement for generation of abrupt transitions. This corresponds in physical terms to negative co-operativity followed by positive co-operativity affecting the catalytic rate constant for the reaction. 4. Previous models for glutamate dehydrogenase cannot adequately account for the results. On the other hand, the model based on both negative and positive co-operativity gives a good fit to the experimental points. 5. The conclusions are discussed in relation to current knowledge of the structure and mechanism of glutamate dehydrogenase.     

Heart rate and gill ventilation in ovigerous and non‐ovigerous edible crabs,Cancer pagurus: The effects of disturbance,substrate and starvation

This study compared the cardiac and ventilatory behaviour of disturbed and settled (48 h recovery) ovigerous Cancer pagurus with the behaviour of non‐ovigerous crabs. It also examined the effects of starvation and a sand substrate on ovigerous females. Ovigerous crabs had significantly lower heart rates than non‐ovigerous crabs. This implies that they have a reduced metabolic rate, confirmed by an earlier study which described lower rates of oxygen uptake in ovigerous crabs. Scaphognathite beat frequency was unaffected by either the presence of eggs, starvation or a sand substrate, but the amplitude of ventilatory pressure changes was higher in settled ovigerous females, implying greater force. The duration of periods of reversed ventilation was also substantially extended in ovigerous crabs, and disturbance caused a ten‐fold increase in the frequency of these reversals, resulting in ventilation being carried out in a predominantly reversed direction. It is suggested that these respiratory adaptations serve to ventilate the egg mass. Disturbance also led to a greater elevation of heart rate in ovigerous crabs, indicating that they are more prone to handling stress. Fed ovigerous crabs spent a higher percentage of time ventilating unilaterally; this response was lost following starvation. Starved ovigerous crabs had the lowest mean heart rate, highest mean ventilatory pressures and, when disturbed above a sand substrate, they showed the highest frequency of reversals of ventilation, possibly in association with their efforts to bury their abdomen bearing the egg mass.     

Effects of temperature on oxygen consumption and heart rate in the semi‐terrestrial crab,Ocypode sa ratan (Forskål)

The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, semi‐terrestrial crab, Ocypode saratan. The Q₁₀ values for both oxygen consumption and heart rate were often <2 and were relatively constant over a wide range of temperature. This suggests that O. saratan is well adapted for life in a high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field. The rates of oxygen consumption of immersed crabs were significantly lower than those of crabs maintained in air at the same temperature.     

Defining difference,forging unity: The co‐construction of race,ethnicity and nation in Belize

This article examines competing nationalist projects which compete to constitute a Belizean nation: pluralist nationalism constructs the nation as ethnically diverse; synthetic nationalism attempts to submerge ethnic or racial difference into a shared national identity; hegemonic nationalism works to attach preferentially a single racial identity to the nation and exclude other identities. Within these projects, the homogenizing processes which construct national sameness are integrally related to the individualizing processes which constitute subnational difference: both national sameness and subnational differences are constituted in terms of race, ethnicity, or a conflation of the two. The article explores how the essentialization of racial, ethnic and national identities facilitates their assimilation of one another.     

Prevalence of gastrointestinal symptoms in patients with influenza,clinical significance,and pathophysiology of human influenza viruses in faecal samples: what do we know?

This review provides for the first time an assessment of the current understanding about the occurrence and the clinical significance of gastrointestinal (GI) symptoms in influenza patients, and their correlation with the presence of human influenza viruses in stools of patients with confirmed influenza virus infection. Studies exploring how human influenza viruses spread to the patient’s GI tract after a primary respiratory infection have been summarized. We conducted a systematic search of published peer-reviewed literature up to June 2015 with regard to the above-mentioned aspects, focusing on human influenza viruses (A(H1N1), A(H1N1)pdm09, A(H3N2), and B). Forty-four studies were included in this systematic review and meta-analysis. The pooled prevalence of any digestive symptoms ranged from 30.9 % (95 % CI, 9.8 to 57.5; I ²?=?97.5 %) for A(H1N1)pdm09 to 2.8 % (95 % CI, 0.6 to 6.5; I ²?=?75.4 %) for A(H1N1). The pooled prevalence of influenza viruses in stool was 20.6 % (95 % CI, 8.9 to 35.5; I ²?=?96.8 %), but their correlation with GI symptoms has rarely been explored. The presence of viral RNA in stools because of haematogenous dissemination to organs via infected lymphocytes is likely, but the potential to cause direct intestinal infection and faecal–oral transmission warrants further investigation. This review highlights the gaps in our knowledge, and the high degree of uncertainty about the prevalence and significance of GI symptoms in patients with influenza and their correlation with viral RNA positivity in stool because of the high level of heterogeneity among studies.     

The significant increase of FcγRIIIA (CD16), a sensitive marker, in patients with coronary heart disease

Our previous studies suggest that Fc receptor III A of immunoglobulin G (FcγRIIIA, also named CD16) is closely correlated to coronary heart disease (CHD). However, whether or not deregulated FcγRIIIA expression is involved in the development of CHD remains largely unclear. Herein, we investigated the FcγRIIIA mRNA expression in the leukocytes, the serum protein level of soluble CD16 (sCD16) and membrane CD16 on monocytes from 100 diagnosed CHD patients and 40 healthy individuals. Our results demonstrated that there was a significant increase of FcγRIIIA at the mRNA level in leukocytes, and at the protein level for both sCD16 in sera and membrane CD16 on monocytes from CHD patients compared to the healthy control. Similarly to the soluble CD14 (sCD14), the level of macrophage colony stimulating factor (M-CSF) in sera was also higher in CHD patients than that in the control individuals. Furthermore, the levels of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1), in sera and the mean fluorescent intensity of intercellular adhesion molecule 1 (ICAM-1, CD54) on CD14(+) CD16(+) monocytes were increased in CHD patients. Overall, these data demonstrated that FcγRIIIA (CD16) is involved in the pathogenesis of CHD by activating monocytes and stimulating inflammation. The significant increase of CD14(+) CD16(+) monocytes in CHD patients therefore suggested that the increase of the FcγRIIIA level might be a sensitive marker for the CHD diagnosis.     

Reaction of thiyl radicals with alcohols,ethers and polyunsaturated fatty acids: A possible role of thiyl free radicals in thiol mutagenesis?

Summary Possible reactions of thiyl free radicals in biological environment are reviewed. In particular hydrogen transfer processes from model C–H compounds like alcohols and ethers as well as from polyunsaturated fatty acids to thiyl radicals are described to proceed with reasonably high rate constants (10₃ – 10⁴ and 10⁶ – 10⁷ M^–1 s^–1, respectively). Thiyl radicals have thus to be considered as potentially hazardous species especially with respect to DNA damage and lipid peroxidation.Paper given at the workshop Molecular Radiation Biology. German Section of the DNA Repair Network, München-Neuherberg, 21.–23.3.1990     

Immune Derangements in Patients with Myelofibrosis: The Role of Treg,Th17, and sIL2Rα

Myelofibrosis (MF), including primary myelofibrosis, post-essential thrombocythemia MF, and post-polycythemia vera MF, has been reported to be associated with autoimmune phenomena. IMiDs have been reported to be effective in some patients with MF, presumably for their immune-modulator effects. We therefore sought to elucidate the immune derangements in patients with MF. We found no differences in T regulatory cells (Treg) and T helper 17 (Th17) cells in MF patients and normal healthy controls. However, we found significantly elevated soluble interleukin 2 alpha (sIL2Rα) in MF patients compared to those with other myeloproliferative neoplasm diseases and normal healthy controls. Our studies with MF patients further revealed that Treg cells were the predominant cells producing sIL2Rα. sIL2Rα and IL2 complex induced the formation of Treg cells but not the formation of Th1 or Th17 cells. sIL2Rα induced CD8⁺ T cell proliferation in the presence of Treg cells. Monocytes or neutrophils had no effect on the production of sIL2Rα by Treg cells. Furthermore, we found plasma sIL2Rα levels were correlated to the auto-immune serology in MPN patients and ruxolitinib significantly inhibits the sIL2Rα production by the Treg cells in MF patients which may explain the effects of ruxolitinib on the relief of constitutional symptoms. All these findings suggest that sIL2Rα likely plays a significant role in autoimmune phenomena seen in patients with MF. Further studies of immune derangement may elucidate the mechanism of IMiD, and exploration of immune modulators may prove to be important for treating myelofibrosis.     

Ritual Efflorescences in a Sri Lankan Muslim community: The interplay of local,national and pan‐Islamic identities

This article examines the interplay of local, national, and international historical and contemporary processes as manifested in a Sri Lankan Muslim village festival. The author shows that the festival is a product of the historical isolation of the village and its attempt to establish a distinct Muslim social identity. In contemporary Sri Lanka a separate Muslim identity is no longer in doubt and the festival has become a focal event for competing and, potentially, mutually exclusive social identities as exemplified by Sufism, Sri Lankan nationalism, and pan‐Islamic fundamentalism.     

Improvement of Speech Function in Patients with Aphasia: The Right Hemisphere,an Enemy or a Friend?

The purpose of our research is to investigate interhemispheric language functional reorganization in patients with gliomas of the left hemisphere using functional magnetic resonance tomography (fMRI) in comparison with the dynamics of speech disorders. A total of 20 patients with a glioma in the left hemisphere underwent fMRI examination and Luria’s neuropsychological testing. The age of patients varied from 26 to 67 years; the mean age was 40 years (median, interquartile range; 13 women and 7 men). The glioma was located in the frontal lobe (12 patients) 34.50–49.75 years; or in the temporal lobe (8 patients). All patients underwent both fMRI scanning and neuropsychological testing on the same day before the surgery and then 3–10 days and 3, 5–7, 12 months after tumor surgery. The handedness was determined by using self-assessment and the Annett Hand Preference Questionnaire. Almost all the subjects were right-handed, and one was ambidexter. On the basis of the analysis of fMRI data in dynamics, all subjects were divided into two groups: (1) patients with no signs of activation of the right hemisphere homologues of Broca’s and Wernicke’s areas (even in 4 patients with severe aphasia) during the follow-up period (at least one year), and (2) patients with signs of activation in the right-sided Broca’s and Wernicke’s areas, which were found in at least several tests (16 patients; 3 of them had normal speech function during the whole follow-up period). We conclude that the lack of consistency between the presence/absence of aphasia and the activation of homologous speech areas in the right hemisphere in fMRI results from individual differences in the involvement of the right hemisphere in speech processes. Thus, we should be very cautious about the hypothesis of reciprocal relationships of the hemispheres in speech function and the use of this hypothesis in speech rehabilitation.