Modelling intraspecific resting egg shape variation in a freshwater fairy shrimp Tanymastix stagnalis (L., 1758) (Crustacea, Branchiopoda)

The shape of the resting eggs of a large branchiopod crustacean, the Anostraca Tanymastix stagnalis , is represented very accurately by analytical expressions. The occurrence of atypical shape of some T. stagnalis eggs may be viewed as a simple change of the analytical expression describing the usual egg shape. Their unusual shape may be explained by a higher embryo volume within an envelope of a given size. Biological implications are briefly discussed and hypothesized in an evolutionary point of view.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 55–60.     

Adult movements between populations in the specialist butterfly Proclossiana eunomia (Lepidoptera, Nymphalidae)

Abstract.

• 1 The structure of local populations of a monophagous butterfly, the bog fritillary Proclossiana eunomia, was studied in a complex of suitable habitat patches separated by spruce plantations or fertilized pasture.
• 2 An unexpected high level of adult movements between habitat patches was detected by a mark—release—recapture technique. Local populations were connected by adult movements across unsuitable habitats, leading to a meta-population structure.
• 3 This evidence of the metapopulation structure of a specialist butterfly challenges the supposed relationship between habitat specialization and closed, isolated populations.
• 4 Males and females of P.eunomia exhibited different spatial behaviours; females were more likely to emigrate and dispersed further than males. These differences in spatial behaviour are related to the mating system.

     

Isolation and characterization of tetranucleotide microsatellite markers in a mouth‐brooding haplochromine cichlid fish (Pseudocrenilabrus multicolor victoriae) from Uganda

Eight tetranucleotide microsatellite loci were isolated from the haplochromine cichlid fish, Pseudocrenilabrus multicolor victoriae, an important model species for studies in respiratory ecology, conservation, and evolution. We surveyed variation at these loci in 23 individuals from western Uganda, finding four to 19 alleles per locus and an average expected heterozygosity of 0.8575. These microsatellite loci will be used to examine gene flow and population structure in Ugandan P. m. victoriae.     

Topography of cholinergic neurons in the brain stem of the human fetus

Cholinacetyltransferase (ChAT) activity has been studied in 56 nuclei of the cerebral trunk in human fetuses at the age of 6-8 lunar months. Cytoplasmic and synaptic ChAT activity has been revealed and three types of neurons for cholinergic synaptic transmission has been distinguished. There are only cholinergic-noncholinoceptive neurons in five macrocellular nuclei of the cranial nerves. In 25 nuclei (paravicellular, reticular, pigmented, sensitive nuclei of the cranial nerves, nuclei of the funiculi posterior and some other switching centres) there are only noncholinergic-cholinoceptive neural cells. In 16 nuclei there are three, and in 8 nuclei--two types of cells. Either noncholinergic-cholinoceptive or cholinergic-noncholinoceptive cells predominate; there is no predominance of cholinergic-cholinoceptive neurons in any of the nuclei. Mapping on the position of the cholinergic synaptic transmission neurons in the cerebral trunk is composed.     

A novel mutation in the <Emphasis Type="Italic">AGXT</Emphasis> gene causing primary hyperoxaluria type I: genotype–phenotype correlation

Primary hyperoxaluria type I (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine : glyoxylate aminotransferase (AGT) which is deficient or mistargeted to mitochondria. PH1 shows considerable phenotypic and genotypic heterogeneity. The incidence and severity of PH1 varies in different geographic regions. DNA samples of the affected members from two unrelated Tunisian families were tested by amplifying and sequencing each of the AGXT exons and intron–exon junctions. We identified a novel frameshift mutation in the AGXT gene, the c.406_410dupACTGC resulting in a truncated protein (p.Gln137Hisfs*19). It is found in homozygous state in two nonconsanguineous unrelated families from Tunisia. These molecular findings provide genotype/phenotype correlations in the intrafamilial phenotypic and permit accurate carrier detection, and prenatal diagnosis. The novel p.Gln137Hisfs*19 mutation detected in our study extend the spectrum of known AGXT gene mutations in Tunisia.     

The effects of O2 on net photosynthesis at low temperature (5°C)

Abstract. It has been shown that atmospheric O₂ can either depress or stimulate the rate of apparent photosynthesis of white mustard depending on the environmental conditions: CO₂ concentration, light intensity and temperature. Stimulation by O₂ was observed only under high photon fluence rate and at high CO₂ concentrations. The critical CO₂ concentration below which O₂ was inhibiting and above which it was stimulating was dependent on the temperature of the assay: for plants grown at 12°C the critical CO₂ concentration was 13.35 mmol at 5° C and 21.92 mmol at 10° C. Stimulation by O₂ depended also on the growth temperature: for measurements at 26.31 mmol m^?3 CO₂, O₂ was stimulating at temperatures less than 12°C for plants grown at 12°C and less than 19°C for plants grown at 27°C. The efficiency of the O₂-dependent stimulation of net photosynthesis was maximum at 9.21 mol m^?3 O₂ at 26.31 mmol m^?3 CO₂. Oxygen-stimulation of net photosynthesis was detected in Nicotiana tabacum L. var Samsun, Lycopersicum esculentum L. and Chenopodium album L. At 5°C and under high photon fluence rate, O₂ increased the carboxylation capacity of the photosynthetic apparatus of mustard and decreased its affinity for CO₂. The O₂ inhibition of the net CO₂ uptake observed at low CO₂ concentrations was the result of a decrease in the affinity for carbon dioxide. The nature of the mechanism which causes the stimulation of photosynthesis is discussed.     

A comparative evaluation of methods of radiologic diagnosis in determining the functional status of the right ventricular myocardium in tetralogy of Fallot

In order to study the informative value of two-dimensional echocardiography (EchoCG) in the assessment of right ventricular function in Fallot's tetrad the results of echocardiography were compared with those of angiocardiography. A total of 40 patients aged 2 to 13 with the cyanotic form of the defect were investigated. Functional indices were calculated using Simpson's rule. The highest correlation in comparing echo- and angiocardiography results was obtained for the end-diastolic volume (r = 0.94), a slightly lower one--for the end-systolic volume (r = 0.92). The mean value of the right ventricular ejection fraction (EF) by the results of echocardiography was 0.62 +/- 0.05 +/- 0.08, by the results of angiocardiography--0.62 +/- 0.05 +/- 0.09. The correlation coefficient characterizing the proximity of EF values, obtained by the above methods, was 0.89. The greatest divergences in the results were noted in the calculation of the minute volume. It can be accounted for by the patients' different state at the time of invasive and non-invasive investigation. A high informative value and accuracy of two-dimensional echocardiography was proved in the assessment of right ventricular function in Fallot's tetrad.     

Importance of signaling via the IFN-α/β receptor on host cells for the realization of the therapeutic benefits of cyclophosphamide for mice bearing a large MOPC-315 tumor

Here we show that low-dose cyclophosphamide (CY), that depends for its therapeutic effectiveness on the immunopotentiating activity of the drug for T cell-mediated tumor-eradicating immunity, is curative for ~80% of wild-type (WT) mice bearing a large s.c. MOPC-315 tumor, but only for ~10% of IFN-α/βR^−/− mice bearing a large s.c. MOPC-315 tumor. Histopathological examination of the s.c. tumors of such mice on day 4 after the chemotherapy revealed that the low dose of CY led to accumulation of T lymphocytes in both the WT and the IFN-α/βR^−/− mice. However, in the CY treated tumor bearing WT mice the T lymphocytes were present throughout the tumor mass and in direct contact with tumor cells, but in the CY treated tumor bearing IFN-α/βR^−/− mice most of the T lymphocytes remained in blood vessels. In addition to being important for CY-induced transendothelial migration of T lymphocytes into the tumor mass, we show here that signaling via the IFN-α/βR is also important for CY-induced control of metastatic tumor progression in the spleen and liver of the tumor bearing mice. Finally, CY cured tumor bearing WT mice were resistant to a subsequent challenge with MOPC-315 tumor cells, but the few CY cured tumor bearing IFN-α/βR^−/− mice were not. Thus, signaling via the IFN-α/βR on host cells in MOPC-315 tumor bearers is important for CY-induced: (a) transendothelial migration of T lymphocytes into the tumor mass and the eradication of the primary tumor, (b) control of metastatic tumor progression, and (c) resistance to a subsequent tumor challenge. This work was supported by Research Grant 03-19 from the American Cancer Society-Illinois Division.     

NO-Ergic transmission and NO as a volume transmitter. Effect of NO on mechanisms of synaptic plasticity and epileptogenesis

Nitric oxide (NO) is a universal intercellular messenger and the only molecule known so far, which satisfies all requirements of the volume (extrasynaptic) neurotransmitter. The effect of NO on target cells is so read in the four-dimensional coordinate system by combining both the spatial and the temporal components of the nervous activity. In this review, the authors, based on literature data and own studies, present a detailed analysis of properties of NO as a volume neurotransmitter at formation of phenomena of synaptic plasticity in norm and pathology. An evaluation is given of cytotoxic and neuroprotective effects of NO under conditions of the brain tissue ischemia and phenomena of hyperexcitability in foci of epileptiform activity. It is emphasized that the long-term potentiation and long-term depression, phenomena of physiological plasticity, can be transformed into pathological plasticity at disturbances of equilibrium between neuroprotective and neurotoxic effects of NO.