Eye colour as a genetic marker for fertility and fecundity of Triatoma infestans (Klug, 1834) Hemiptera,Reduviidae, Triatominae

Eye colour of Triatoma infestans is controlled at a single autosomal locus, with black-eye as the dominant gene and red-eye as the recessive. Inheritance of these characters follows a classical Mendelian system, enabling eye colour to be used as a marker for studies of mating frequency. We found no significant differences in oviposition rates and egg hatching rates irrespective of parental phenotypes. Different mating schedules between red-eye and black-eye parents showed that eye colour did not affect mating competence. Females mated with a single male or with different males together or in succession produced similar numbers of fertile eggs, with the eye colour of the offspring reflecting exposure to the different males. We conclude that although a single mating can provide sufficient sperm for the whole reproductive life of the female, multiple matings can result in balanced assortative sperm usage from the spermatheca.     

Strong and symmetric halogen bonding in coordination compounds of carboxylic acid derivatives; the crystal structure of (3,6-dithiaoctanedioato-S,S′-(3,6-dithiaoctanedioic acid-S,S′)-copper(I) redetermined at 173 K

3,6-dithianoctanedioic acid forms a Cu(I) compound in which electrical neutrality is achieved by elaborate hydrogen bonding and sharing on protons. The title compund crystallizes in the monoclinic space group P2/n with Z = 2. Unit-cell parameters are a = 11.625(2), b = 7.664(1), c = 9.874(2) Å, β = 95.16°, D_m = 1.80(2), D_c = 1.83 g cm^?3. The structure was solved by means of standard direct methods and refined with full-matrix least-squares techniques to an R-value of 0.026 (R_w = 0.042). The Cu(I) ion is tetrahedrally coordinated by four thioether S-atoms (CuS = 2.29–2.33 Å). The molecules are linked by very strong hydrogen bonds between non-coordinating carboxylate groups in such a way that the average number of acidic hydrogens per molecule is three. One of these hydrogens lies on a twofold axis and forms a short symmetrical hydrogen bond, with a OO distance of 2.441(2) Å. Unusual features in the infrared spectrum of this compund can be interpreted on the basis of the observed crystal structure.     

Adaptation of BHK cells producing a recombinant protein to serum-free media and protein-free medium

In this work a recombinant BHK21 clone producing a fusion protein with potential application in tumour target therapy was adapted to five different serum-free media (SFM) and to a protein-free medium (PFM). Only the PFM did not require a gradual adaptation to cell growth in the absence of serum. All tested SFM required a gradual adaptation (up to 35 days). For the majority of the SFM tested, cell specific productivity was not affected by the decrease in serum concentration during adaptation; however, cell growth was significantly affected by the serum decrease. Both cell growth and productivity were increased when PFM SMIF6 was used instead of the control medium. Long term measurements (approximately 100 days) of cell specific productivity for PFM and the two best SFM showed that productivity was maintained. This indicates the media capability to be used in long term production processes.     

Occurrence of hydroxylated jasmonic acids in leaflets of Solanum demissum plants grown under long- and short-day conditions

Under short-day (SD) conditions both 11-OH-jasmonic acid (11-OH-JA) and a smaller quantity of 12-OH-JA occurred in leaflets of Solanum demissum Lindl. Plants which had formed tubers. This is the first time that 11-OH-JA has been detected as a native substance in higher plants. Under long-day (LD) conditions no tubers were formed and none of these compounds were detectable. A positive correlation was found between the occurrence of 11-OH-JA and 12-OH-JA in leaflets of S. demissum and tuber formation, but a causal relation has yet to be proved. The (-)-JA content in leaflets was not significantly different under short and long days. Mild stress applied to detached SD and LD leaflets caused a rapid accumulation of JA in these leaflets. Upon this treatment an increase in the levels of hydroxylated JAs was detected in SD leaflets only.
JA was a potent promotor of tuber formation in vitro in S. demissum explants. Lipoxygenase (LOX: EC 1.13.11.12) is involved in the biosynthesis of JA. Under SD conditions, application of salicylhydroxamic acid (SHAM), an inhibitor of LOX activity, to the roots did not prevent tuber formation in vivo. It is suggested that daylength controls the hydroxylation of JA. The enzyme(s), responsible for the hydroxylation of JA, would only be effective under SD conditions.     

The effect of cooling rate and of dimethyl sulfoxide concentration on the ultrastructure of neonatal rat heart cells after freezing and thawing

The ultrastructure of neonatal rat heart cells in suspension and in tissue culture after freezing at optimal, suboptimal, and supraoptimal cooling rates with 2.5, 5, 7.5, and 10% DMSO was investigated. The effect of DMSO treatment only on the structure of the cells was also studied. A comparison was made with the survival in culture.Without freezing, increasing DMSO concentrations caused an increase of morphological damage, correlating with a decrease of the survival in culture. With 2.5% DMSO there was no difference with untreated cells. At higher DMSO concentrations, the ultrastructural damage increased from spaces between cell membrane and cytoplasm at 5% DMSO to interrupted cell membranes, swollen or destroyed mitochondria, and nuclei with clumped chromatin at 10% DMSO.After freezing at optimal or nonoptimal cooling rates with 5 or 7.5% DMSO, the ultrastructure correlated well with the survival. After freezing with 2.5 or 10% DMSO at optimal or nonoptimal cooling rates, differences in survival were found, which were not reflected in the ultrastructure of the cell. After 8 days of culturing, cells which were frozen at all the different cooling rates and DMSO concentrations appeared to have a normal structure.     

Safety in numbers? Shoaling behaviour of the Amazonian red-bellied piranha

Red-bellied piranha (Pygocentrus nattereri) shoals have a fearsome reputation. However, the variety and abundance of piranha predators in the flooded forests of the Amazon in which they live indicate that an important reason for shoal formation may be predator defence. Experiments using wild-caught piranhas supported the hypothesis that individual perception of risk, as revealed by elevated ventilatory frequency (opercular rate), is greater in small shoals. Moreover, exposure to a simulated predator attack by a model cormorant demonstrated that resting opercular rates are regained more quickly by piranhas in shoals of eight than they are in shoals of two. Together, these results show that shoaling has a cover-seeking function in this species.     

Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis

Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a flat beta-barrel structure with surface-exposed aromatic rings, whereas the 3D structure of Gr-EXPB1-D2 was remarkably similar to plant expansins. Gr-EXPB1 shows highest sequence similarity to two extracellular proteins from saprophytic soil-inhabiting Actinobacteria, and includes a bacterial type II carbohydrate-binding module. These results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.     

Benzopyrans from Curvularia sp., an endophytic fungus associated with Ocotea corymbosa (Lauraceae)

An isolate of Curvularia sp. was obtained from the leaves of Ocotea corymbosa, a native plant of the Brazilian Cerrado. The ethyl acetate extract from culture of this fungus afforded two benzopyran derivatives: (2'S)-2-(propan-2'-ol)-5-hydroxy-benzopyran-4-one (2) and 2,3-dihydro-2-methyl-benzopyran-4,5-diol (4); and two known benzopyrans: 2-methyl-5-methoxy-benzopyran-4-one (1) and (2R)-2,3-dihydro-2-methyl-5-methoxy-benzopyran-4-one (3). The structures of 2 and 4 were established on the basis of comprehensive spectroscopic analysis, mainly using 1D and 2D NMR experiments. The benzopyrans 1 and 2 showed weak in vitro antifungal activity against Cladosporium sphaerospermum and C. cladosporioides. Analyses of the biological activities were also carried out on HeLa (human cervix tumor) and CHO (Chinese hamster ovary) cells, aiming to evaluate their potential effects on mammalian cell line proliferation. Results from both cell lines indicated that compound 2 was able to induce cell proliferation: 70% on HeLa cells and 25% on CHO cells.     

Drosophila CLASP is required for the incorporation of microtubule subunits into fluxing kinetochore fibres

The motion of a chromosome during mitosis is mediated by a bundle of microtubules, termed a kinetochore fibre (K-fibre), which connects the kinetochore of the chromosome to a spindle pole. Once formed, mature K-fibres maintain a steady state length because the continuous addition of microtubule subunits onto microtubule plus ends at the kinetochore is balanced by their removal at their minus ends within the pole. This condition is known as 'microtubule poleward flux'. Chromosome motion and changes in position are then driven by changes in K-fibre length, which in turn are controlled by changes in the rates at which microtubule subunits are added at the kinetochore and/or removed from the pole. A key to understanding the role of flux in mitosis is to identify the molecular factors that drive it. Here we use Drosophila melanogaster S2 cells expressing alpha-tubulin tagged with green fluorescent protein, RNA interference, laser microsurgery and photobleaching to show that the kinetochore protein MAST/Orbit - the single CLASP orthologue in Drosophila - is an essential component for microtubule subunit incorporation into fluxing K-fibres.     

TEMPONE reduces renal dysfunction and injury mediated by oxidative stress of the rat kidney

Here we investigate the effects of the stable, water-soluble nitroxyl radical, TEMPONE, on renal dysfunction and injury caused by ischemia/reperfusion (I/R) of the rat kidney in vivo. TEMPONE significantly improved both glomerular and tubular function (serum urea, creatinine, creatinine clearance, and fractional excretion of Na(+)) in a dose-dependent manner and significantly attenuated the reperfusion-injury associated with I/R (urinary N-acetyl-beta-D-glucosaminidase, aspartate aminotransferase, assessment of renal histology). TEMPONE also markedly reduced the immunohistochemical evidence of the formation of nitrotyrosine and poly(ADP-ribose), indicating reduction of nitrosative and oxidative stress, respectively. The latter was reflected in vitro, where TEMPONE significantly reduced cellular injury of primary cultures of rat renal proximal tubular (PT) cells caused by hydrogen peroxide in a dose-dependent manner. Importantly, in contrast to its in vivo metabolite TEMPOL (which also provided protective effects against renal I/R and oxidative stress of PT cells), TEMPONE reduced renal dysfunction and injury without causing a significant reduction in blood pressure upon administration. These results suggest, for the first time, that TEMPONE can reduce the renal dysfunction and injury caused by I/R and the injury caused to PT cells by oxidative stress without producing the adverse cardiovascular effects observed when using other nitroxyl radicals.