The biological activity of interferon alpha is influenced by two distinct regions in the protein

With the aim to assign differences in activity between murine interferon-alpha 1 and -alpha 4 to specific amino acids, we have constructed hybrid genes and analysed the antiviral properties of the corresponding hybrid proteins. The hybrid genes were constructed by means of homologous recombination between the alpha 1 and alpha 4 genes in Escherichia coli. Hybrids in which the N-terminal part is derived from alpha 1 show that two regions have a major effect on the activity: amino acid 10-20 and 55-67. When comparing hybrids with N-terminal alpha 4 sequences, transitions in activity are found in the same regions. Interestingly, the curves for the two sets of hybrids are exactly each others mirror image.     

Laying, development and hatching of eggs of the fish ectoparasite Argulus japonicus (Crustacea: Branchiura)

Egg laying of the fish-louse Argulus japonicus was observed and examined experimentally. The effect of temperature on development time and hatching yielded an inverse exponential function. Hatching started after 61–10 days in a temperature span of 15–35 °C. Eggs are laid in strings on hard substrata and covered by a gelatinous material. Females lay between 1–9 strings, 5–226 eggs per string, arranged in 1–6 rows. Four embryonic developmental stages were recognized and the mean hatching efficiency was 50% in the optimal temperature range of 20–30 °C. Hatching efficiency was not related to either the number of eggs in a string or the total number of eggs laid by any particular female. Argulus japonicus displays continuous egg-laying activity with a possibility of an overwintering mechanism which suggests a seasonality of a sort.     

Salt tolerance in Lycopersicon species. IV. Efficiency of marker-assisted selection for salt tolerance improvement

The usefulness of marker-assisted selection (MAS) to develop salt-tolerant breeding lines from a F₂ derived from L. esculentum x L. pimpinellifolium has been studied. Interval mapping methodology of quantitative trait locus (QTL) analysis was used to locate more precisely previously detected salt tolerance QTLs. A new QTL for total fruit weight under salinity (TW) near TG24 was detected. Most of the detected QTLs [3 for TW, 5 for fruit number, (FN) and 4 for fruit weight (FW)] had low R ² values, except the FW QTL in the TG180-TG48 interval, which explains 36.6% of the total variance. Dominant and overdominant effects were detected at the QTLs for TW, whereas gene effects at the QTLs for FJV and FW ranged from additive to partial dominance. Phenotypic selection of F₂ familes and marker-assisted selection of F₃ families were carried out. Yield under salinity decreased in the F₂ generation. F₃ means were similar to those of the F₁ as a consequence of phentoypic selection. The most important selection response for every trait was obtained from the F₃ to F₄ where MAS was applied. While F₃ variation was mainly due to the within-family component, in the F₄ the FN and FW between-family component was larger than the within-family one, indicating an efficient compartmentalization and fixation of QTLs into the F₄ families. Comparison of the yield of these families under control versus saline conditions showed that fruit weight is a key trait to success in tomato salt-tolerance improvement using wild Lycopersicon germplasm. The QTLs we have detected under salinity seem to be also working under control conditions, although the interaction family x treatment was significant for TW, thereby explaining the fact that the selected families responded differently to salinity.     

Synthesis,Biological Evaluation,and Molecular Modeling Studies of New 1,3,4-Thiadiazole Derivatives as Potent Antimicrobial Agents

In this work, the synthesis, characterization, and biological activities of a new series of 1,3,4-thiadiazole derivatives were investigated. The structures of final compounds were identified using ¹H-NMR, ¹³C-NMR, elemental analysis, and HRMS. All the new synthesized compounds were then screened for their antimicrobial activity against four types of pathogenic bacteria and one fungal strain, by application of the MIC assays, using Ampicilin, Gentamycin, Vancomycin, and Fluconazole as standards. Among the compounds, the MIC values of 4 and 8 μg/mL of the compounds 3f and 3g , respectively, are remarkable and indicate that these compounds are good candidates for antifungal activity. The docking experiments were used to identify the binding forms of produced ligands with sterol 14-demethylase to acquire insight into relevant proteins. The MD performed about 100 ns simulations to validate selected compounds’ theoretical studies. Finally, using density functional theory (DFT) to predict reactivity, the chemical characteristics and quantum factors of synthesized compounds were computed. These results were then correlated with the experimental data. Furthermore, computational estimation was performed to predict the ADME properties of the most active compound 3f .     

Factors affecting Citrus tree isozyme-gene expression

Ten enzymatic systems of Citrus species and cultivars have been evaluated for identification purposes and for genetic variability studies. The following factors that could affect their expression were studied: season of sampling, location, rootstock, position of the branch, infection, and age of the tree. Differences involving the presence-absence of the Cu/Zn SOD within the same tree were found. This difference is mainly related to the position of the leaf relative to the sunlight. No change was observed at any of the ten enzymatic systems assayed regarding the location, the rootstock, the growing condition, the season, or the infection with most virus and virus-like pathogens. Viroids induced noticeable changes on 6PG and PRXa zymograms in C. medica. A new peroxidase (not present in healthy plants) was detected that could be related to appearance of symptoms. This may induce errors when trees without sanitary control are characterized by this enzymatic system. On the other hand, it provides a new possibility for studying the plant response to the presence of viroids. An effect of age, from 3 months up to 12 years, was observed on citrange Troyer and mandarin Cleopatra PRX, MDH and 6PG patterns. An important change occurs around the first year, most likely related to the end of the seedling stage. This is followed by a long transition phase, the end of which (around 9 years later) coincides with a change in the PRX pattern. These age-related changes seem to involve post-translational modifications of pre-existing isozymes.     

Falling Victim to Wasps in the Air: A Fate Driven by Prey Flight Morphology?

In prey-predator systems where the interacting individuals are both fliers, the flight performance of both participants heavily influences the probability of success of the predator (the prey is captured) and of the prey (the predator is avoided). While the flight morphology (an estimate of flight performance) of predatory wasps has rarely been addressed as a factor that may contribute to explain prey use, how the flight morphology of potential prey influences the output of predator-prey encounters has not been studied. Here, we hypothesized that flight morphology associated with flight ability (flight muscle mass to body mass ratio (FMR) and body mass to wing area ratio (wing loading, WL)) of Diptera affect their probability of being captured by specialized Diptera-hunting wasps (Bembix merceti and B. zonata), predicting a better manoeuvrability and acceleration capacity achieved by higher FMR and lower WL, and flight speed achieved by higher WL. In addition, wasp species with better flight morphology should be less limited by an advantageous Diptera flight morphology. Overall, the abundance of dipterans in the environment explained an important part of the observed variance in prey capture rate. However, it was not the only factor shaping prey capture. First, higher prey abundance was associated with greater capture rate for one species (B. merceti), although not for the other one. Second, the interaction observed between the environmental dipteran availability and dipteran WL for B. zonata suggests that greater dipteran WL (this probably meaning high cruising speed) decreased the probability of being captured, as long as fly abundance was high in the environment. Third, greater dipteran FMR (which likely means high manoeuvrability and acceleration capacity) helped to reduce predation by B. merceti if, again, dipterans were abundant in the environment. Wasp WL only varied with body mass but not between species, thereby hardly accounting for inter-specific differences in the wasps’ predatory patterns. However, the greater FMR of B. zonata, which implies better flight performance and greater load-lifting capacity, may explain why the capture rate in the two wasp species is affected by different factor interactions. In conclusion, although prey availability remains the primary factor shaping prey use, prey flight morphology seems to gain an additional role under conditions of abundant prey, when wasps can avoid flies with better flight ability.     

Nematodes from the squeaker fishes Synodontis nigromaculatus and S. vanderwaali from the Okavango River, Botswana, including three new species

Five nematode species were recorded from the stomach and rectum of the spotted squeaker Synodontis nigromaculatus Boulenger or the finetooth squeaker S. vanderwaali Skelton & White (Mochokidae, Siluriformes) from the Okavango River, Botswana: Falcaustra similis n. sp. (Kathlaniidae), Labeonema africanum n. sp. (Cosmocercidae), Synodontisia okavangoensis n. sp. (Pharyngodonidae), Procamallanus ( Procamallanus ) laeviconchus (Wedl, 1861) (Camallanidae) and Spinitectus sp. (Cystidicolidae) (only a single female). F. similis (type-host Synodontis nigromaculatus ) differs from the similar species F. straeleni Campana-Rouget, 1961 mainly by the number and disposition of the male caudal papillae and the structure of the mouth; L. africanum (type-host S. nigromaculatus ) differs from its congeners in having distinctly longer spicules (105-120 microm), a relatively shorter gubernaculum (30-36 microm) and in the number and arrangement of the male caudal papillae; Synodontisia okavangoensis (type-host Synodontis nigromaculatus ) is characterised principally by crescent-shaped cephalic papillae, length (87 microm) and shape of the spicule as well as large eggs (0.156-0.180x69-102 microm). Synodontisia moraveci Anderson & Lim, 1996 is transferred to a newly established genus, Royandersonia n. g., (as its type-species) as R. moraveci (Anderson & Lim, 1996) n. comb. Some taxonomic problems concerning Procamallanus ( P .) laeviconchus are discussed. All species were studied by scanning electron microscopy for the first time.     

Cluster structure of anaerobic aggregates of an expanded granular sludge bed reactor

The metabolic properties and ultrastructure of mesophilic aggregates from a full-scale expanded granular sludge bed reactor treating brewery wastewater are described. The aggregates had a very high methanogenic activity on acetate (17.19 mmol of CH(4)/g of volatile suspended solids [VSS].day or 1.1 g of CH(4) chemical oxygen demand/g of VSS.day). Fluorescent in situ hybridization using 16S rRNA probes of crushed granules showed that 70 and 30% of the cells belonged to the archaebacterial and eubacterial domains, respectively. The spherical aggregates were black but contained numerous whitish spots on their surfaces. Cross-sectioning these aggregates revealed that the white spots appeared to be white clusters embedded in a black matrix. The white clusters were found to develop simultaneously with the increase in diameter. Energy-dispersed X-ray analysis and back-scattered electron microscopy showed that the whitish clusters contained mainly organic matter and no inorganic calcium precipitates. The white clusters had a higher density than the black matrix, as evidenced by the denser cell arrangement observed by high-magnification electron microscopy and the significantly higher effective diffusion coefficient determined by nuclear magnetic resonance imaging. High-magnification electron microscopy indicated a segregation of acetate-utilizing methanogens (Methanosaeta spp.) in the white clusters from syntrophic species and hydrogenotrophic methanogens (Methanobacterium-like and Methanospirillum-like organisms) in the black matrix. A number of physical and microbial ecology reasons for the observed structure are proposed, including the advantage of segregation for high-rate degradation of syntrophic substrates.