A mitogenomic approach to the taxonomy of pollocks: <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> and <Emphasis Type="Italic">T. finnmarchica</Emphasis> represent one single species

Background  

The walleye pollock (Theragra chalcogramma) and Norwegian pollock (T. finnmarchica) are confined to the North Pacific and North Atlantic Oceans, respectively, and considered as distinct species within the family Gadidae. We have determined the complete mtDNA nucleotide sequence of two specimens of Norwegian pollock and compared the sequences to that of 10 specimens of walleye pollock representing stocks from the Sea of Japan and the Bering Sea, 2 specimens of Atlantic cod (Gadus morhua), and 2 specimens of haddock (Melanogrammus aeglefinus).     

Identification and comparative analysis of <Emphasis Type="Italic">Brassica juncea</Emphasis> pathogenesis-related genes in response to hormonal,biotic and abiotic stresses

Pathogenesis-related proteins (PRs) are the antimicrobial proteins which are commonly used as signatures of defense signaling pathways and systemic acquired resistance. However, in Brassica juncea most of the PR proteins have not been fully characterized and remains largely enigmatic. In this study, full-length cDNA sequences of SA (PR1, PR2, PR5) and JA (PR3, PR12 and PR13) marker genes were isolated from B. juncea and were named as BjPR proteins. BjPR proteins showed maximum identity with known PR proteins of Brassica species. Further, expression profiling of BjPR genes were investigated after hormonal, biotic and abiotic stresses. Pre-treatment with SA and JA stimulators downregulates each other signature genes suggesting an antagonistic relationship between SA and JA in B. juncea. After abscisic acid (ABA) treatment, SA signatures were downregulated while as JA signature genes were upregulated. During Erysiphe cruciferarum infection, SA- and JA-dependent BjPR genes showed distinct expression pattern both locally and systemically, thus suggesting the activation of SA- and JA-dependent signaling pathways. Further, expression of SA marker genes decreases while as JA-responsive genes increases during drought stress. Interestingly, both SA and JA signature genes were induced after salt stress. We also found that BjPR genes displayed ABA-independent gene expression pattern during abiotic stresses thus providing the evidence of SA/JA cross talk. Further, in silico analysis of the upstream regions (1.5 kb) of both SA and JA marker genes showed important cis-regulatory elements related to biotic, abiotic and hormonal stresses.     

Aboveground mammal and invertebrate exclusions cause consistent changes in soil food webs of two subalpine grassland types,but mechanisms are system‐specific

Ungulates, smaller mammals, and invertebrates can each affect soil biota through their influence on vegetation and soil characteristics. However, direct and indirect effects of the aboveground biota on soil food webs remain to be unraveled. We assessed effects of progressively excluding aboveground large‐, medium‐ and small‐sized mammals as well as invertebrates on soil nematode diversity and feeding type abundances in two subalpine grassland types: short‐ and tall‐grass vegetation. We explored pathways that link exclusions of aboveground biota to nematode feeding type abundances via changes in plants, soil environment, soil microbial biomass, and soil nutrients. In both vegetation types, exclusions caused a similar shift toward higher abundance of all nematode feeding types, except plant feeders, lower Shannon diversity, and lower evenness. These effects were strongest when small mammals, or both small mammals and invertebrates were excluded in addition to excluding larger mammals. Exclusions resulted in a changed abiotic soil environment that only affected nematodes in the short‐grass vegetation. In each vegetation type, exclusion effects on nematode abundances were mediated by different drivers related to plant quantity and quality. In the short‐grass vegetation, not all exclusion effects on omni–carnivorous nematodes were mediated by the abundance of lower trophic level nematodes, suggesting that omni–carnivores also depended on other prey than nematodes. We conclude that small aboveground herbivores have major impacts on the soil food web of subalpine short‐ and tall‐grass ecosystems. Excluding aboveground animals caused similar shifts in soil nematode assemblages in both subalpine vegetation types, however, mechanisms turned out to be system‐specific.     

Interactions of temperature and photoperiod in the control of flowering of latitudinal and altitudinal populations of wild strawberry (Fragaria vesca)

Floral induction and development requirements of a range of latitudinal and altitudinal Norwegian populations of the wild strawberry Fragaria vesca L. have been studied in controlled environments. Rooted runner plants were exposed to a range of photoperiods and temperatures for 5 weeks for floral induction and then transferred to long day (LD) at 20°C for flower development. A pronounced interaction of temperature and photoperiod was shown in the control of flowering. At 9°C, flowers were initiated in both short day (SD) and LD conditions, at 15 and 18°C in SD only, whereas no initiation took place at 21°C regardless of daylength conditions. The critical photoperiod for SD floral induction was about 16 h and 14 h at 15 and 18°C, respectively, the induction being incomplete at 18°C. The optimal condition for floral induction was SD at 15°C. A minimum of 4 weeks of exposure to such optimal conditions was required. Although the populations varied significantly in their flowering performance, no clinal relationship was present between latitude of origin and critical photoperiod. Flower development of SD-induced plants was only marginally advanced by LD conditions, while inflorescence elongation and runnering were strongly enhanced by LD at this stage. The main shift in these responses took place at photoperiods between 16 and 17 h. Unlike all other populations studied, a high-latitude population from 70°N ('Alta') had an obligatory vernalization requirement. Although flowering and fruiting in its native Subarctic environment and after overwintering in the field in south Norway, this population did not flower in the laboratory in the absence of vernalization, even with 10 or 15 weeks of exposure to SD at 9°C. Flowering performance in the field likewise indicated a vernalization requirement of this high-latitude population.     

Stabilizing Exposure of Conserved Epitopes by Structure Guided Insertion of Disulfide Bond in HIV-1 Envelope Glycoprotein

Entry of HIV-1 into target cells requires binding of the viral envelope glycoprotein (Env) to cellular receptors and subsequent conformational changes that culminates in fusion of viral and target cell membranes. Recent structural information has revealed that these conformational transitions are regulated by three conserved but potentially flexible layers stacked between the receptor-binding domain (gp120) and the fusion arm (gp41) of Env. We hypothesized that artificial insertion of a covalent bond will ‘snap’ Env into a conformation that is less mobile and stably expose conserved sites. Therefore, we analyzed the interface between these gp120 layers (layers 1, 2 and 3) and identified residues that may form disulfide bonds when substituted with cysteines. We subsequently probed the structures of the resultant mutant gp120 proteins by assaying their binding to a variety of ligands using Surface Plasmon Resonance (SPR) assay. We found that a single disulfide bond strategically inserted between the highly conserved layers 1 and 2 (C65-C115) is able to ‘lock’ gp120 in a CD4 receptor bound conformation (in the absence of CD4), as indicated by the lower dissociation constant (Kd) for the CD4-induced (CD4i) epitope binding 17b antibody. When disulfide-stabilized monomeric (gp120) and trimeric (gp140) Envs were used to immunize rabbits, they were found to elicit a higher proportion of antibodies directed against both CD4i and CD4 binding site epitopes than the wild-type proteins. These results demonstrate that structure-guided stabilization of inter-layer interactions within HIV-1 Env can be used to expose conserved epitopes and potentially overcome the sequence diversity of these molecules.     

Novel c.2216T > C (p.I739T) Mutation in Exon 13 and c.1481T > A (p.L494X) Mutation in Exon 8 of MUT Gene in a Female with Methylmalonic Acidemia

We report herein a 1.5-year-old girl with methylmalonic acidemia (MMA) in whom two missense mutations were found: a novel I739T mutation located in exon 13 and the L494X mutation in exon 8. The results of organic acid test showed a pronounced increase in methylmalonate excretion with increased methylcitrate and 3-OH-propionate excretion, leading to a diagnosis of MMA, and Vitamin B12 administration was started. Analysis of the mut gene confirmed a T-to-A substitution at nucleotide position 1481 in exon 8 and a T-to-C substitution at nucleotide position 2216 in exon 13, leading to the amino acid isoleucine at position 739 being changed to threonine, resulting in c.2216T > C (p.I739T). The patient has now been on high-dose oral administration of Vitamin B12 and carnitine therapy (900 mg of levocarnitine chloride) for 5 years without experiencing further attacks, and her cognitive and motor development is normal. Further tests on residual enzyme activity, as well as experience with more cases, may shed light on the relationship between gene mutations and phenotypes in MMA.     

The effect of a daytime 60-min nap opportunity on postural control in highly active individuals

Although napping is commonly used as a strategy to improve numerous physical and cognitive performances, the efficacy of this strategy for improving postural balance has not yet been elucidated. Thus, the aim of this study was to conduct a comprehensive examination of the effect of a 60 min nap opportunity (N60) on different components of postural control. Ten highly active individuals (age = 27 ± 3.5 y, height = 1.75 ± 0.52 m, weight = 66.02 ± 8.63 kg) performed, in a randomized order, two afternoon test sessions following no nap (NN) and N60. Postural balance was assessed using the sensory organisation test (SOT), the unilateral stance test (UST), and the limits of Stability Test performed on NeuroCom^® Smart Balance Master. The subjective rating of sleepiness before and after the nap conditions was also assessed. Compared to NN, N60 improved the composite balance score (p < 0.05, ES = 0.75, Δ = 5.3%) and the average and maximum percentage balance in the most challenging postural conditions of the SOT (p < 0.05 for SOT-4 and 5 and p < 0.0005 for SOT-6; ES range between 0.58 and 1.1). This enhanced postural balance in N60 was accompanied with improved visual (p < 0.05; ES = 0.93; Δ = 8.9%) and vestibular (p < 0.05; ES = 0.81; Δ = 10.5%) ratios and a reduced level of sleepiness perception (p < 0.001, ES = 0.87). However, no significant differences were found in any of the UST and LOS components’ scores (p > 0.05). Overall, a 60 min post lunch nap opportunity may be viable for improving static balance, although further work, involving larger samples and more complex motor activities, is warranted.