Assortative Mating and Fertility in two Drosophila subobscura Strains with different Mitochondrial DNA Haplotypes

The mating pattern and female fertility on the two main mitochondrial DNA haplotypes (I and II) of Drosophila subobscura were studied, in an attempt to find possible differences between them in relation to sexual selection or isolation that could explain the populational dynamics and the co-existence of these two strains in nature. The mating pattern indicated an assortative mating in population cages, where couples of the same haplotype, mainly those of haplotype I, mated more often. However, the significations detected in laboratory conditions disappeared in wild populations, where random mating was the rule. The female fertility also showed differences in the laboratory compared to the wild, since couples with haplotype I males were more efficient in the laboratory populations. These results, together with others that we previously obtained, either point to selection acting directly on the mtDNA or to the presence of some kind of cytonuclear co-adaptation in these two haplotypes, although this must be modulated by other factors that change with the seasons and time. The end result could well be a balance of opposite forces acting on both haplotypes.     

Manifestations of resistance to Haemonchus contortus in sheep: Worm populations and abomasal changes in sheep superinfected with 1,000,000 larvae of H. contortus

The super-infecting dose produced a marked rise in gastric pH in all sheep from the 3rd day after administration of larvae. Expulsion of the existing population of adult worms may have begun on the 4th day but was still only completed in 3/6 sheep on the 5th day. The larvae caused extensive damage in the individual glands which they parasitised. Very few of the 10⁶ larvae survived for 27 days and only in 1/8 sheep had they developed beyond early 4th stage at 27 days. Extensive histological changes were seen in the fundic mucosa beginning as early as 2 days after the superinfection. While the pH change preceded expulsion of the adults and was consistent in its timing, the timing of the expulsion was irregular. This throws doubt on the hypothesis that the change in physico-chemical conditions produced by the superinfecting larvae is the only cause of the expulsion of the adult worms.     

Comparison of the Molecular Forms of the Kex2/Subtilisin-Like Serine Proteases SPC2, SPC3, and Furin in Neuroendocrine Secretory Vesicles Reveals Differences in Carboxyl-Terminus Truncation and Membrane Association

Abstract: The molecular forms and membrane association of SPC2, SPC3, and furin were investigated in neuroendocrine secretory vesicles from the anterior, intermediate, and neural lobes of bovine pituitary and bovine adrenal medulla. The major immunoreactive form of SPC2 was the full-length enzyme with a molecular mass of 64 kDa. The major immunoreactive form of SPC3 was truncated at the carboxyl terminus and had a molecular mass of 64 kDa. Full-length 86-kDa SPC3 with an intact carboxyl terminus was found only in bovine chromaffin granules. Immunoreactive furin was also detected in secretory vesicles. The molecular masses of 80 and 76 kDa were consistent with carboxyl-terminal truncation of furin to remove the transmembrane domain. All three enzymes were distributed between the soluble and membrane fractions of secretory vesicles although the degree of membrane association was tissue specific and, in the case of SPC3, dependent on the molecular form of the enzyme. Significant amounts of membrane-associated and soluble forms of SPC2, SPC3, and furin were found in pituitary secretory vesicles, whereas the majority of the immunoreactivity in chromaffin granules was membrane associated. More detailed analyses of chromaffin granule membranes revealed that 86-kDa SPC3 was more tightly associated with the membrane fraction than the carboxyl terminus-truncated 64-kDa form.     

Structural features of acetylated galactomannans from green Coffea arabica beans

Polysaccharides were extracted from green Coffea arabica beans with water (90 °C, 1 h). Galactomannans were isolated from the water extract using preparative anion-exchange chromatography. Almost all of the galactomannans eluted in two neutral populations, while almost all of the arabinogalactans bound to the column, indicating that these arabinogalactans contain charged groups. Analysis of the molecular weight distribution of the two neutral populations showed that they differ in their molecular weight. Further characterization of these neutral populations by NMR and by MALDI-TOF MS after enzymatic degradation with an endo-mannanase, showed the presence of acetyl groups linked to the galactomannans, a feature not previously described for this type of polysaccharides from coffee beans. It was found that the high molecular weight (ca. 2000 kDa) neutral fraction was highly substituted both with galactose residues and acetyl groups, while the low molecular weight (ca. 20 kDa) population was much less substituted. Based on these results it can be concluded that at least two distinctly different populations of galactomannans are present in green coffee beans. It was also shown that the degradation of the galactomannans from green coffee beans with an endo-mannanase from A. niger is hindered by the presence of acetyl groups.     

Enhanced uptake of soil Pb and Zn by Indian mustard and winter wheat following combined soil application of elemental sulphur and EDTA

Enhancement of Pb and Zn uptake by Indian mustard (Brassica juncea (L.) Czern.) and winter wheat (Triticum aestivumL.) grown for 50 days in pots of contaminated soil was studied with application of elemental sulphur (S) and EDTA. Sulphur was added to the soil at 5 rates (0–160 mmol kg^?1) before planting, and EDTA was added in solution at 4 rates (0–8 mmol kg^?1) after 40 days of plant growth. Additional pots were established with the same rates of S and EDTA but without plants to monitor soil pH and CaCl₂-extractable heavy metals. The highest application rate of S acidified the soil from pH 7.1 to 6.0. Soil extractable Pb and Zn and shoot uptake of Pb and Zn increased as soil pH decreased. Both S and EDTA increased soil extractable Pb and Zn and shoot Pb and Zn uptake. EDTA was more effective than S in increasing soil extractable Pb and Zn, and the two amendments combined had a synergistic effect, raising extractable Pb to ¿1000 and Zn to ¿6 times their concentrations in unamended control soil. Wheat had higher shoot yields than Indian mustard and increasing application rates of both S and EDTA reduced the shoot dry matter yields of both plant species to as low as about half those of unamended controls. However, Indian mustard hyperaccumulated Pb in all EDTA treatments tested except the treatment with no S applied, and the maximum shoot Pb concentration was 7100 mg kg^?1 under the highest application rates of S and EDTA combined. Wheat showed similar trends, but hyperaccumulation (1095 mg kg^?1) occurred only at the highest rates of S and EDTA combined. Similar trends in shoot Zn were found, but with lower concentrations than Pb and far below hyperaccumulation, with maxima of 777 and 480 mg kg^?1 in Indian mustard and wheat. Despite their lower yields, Indian mustard shoots extracted more Pb and Zn from the soil (up to 4.1 and 0.45 mg pot^?1) than did winter wheat (up to 0.72 and 0.28 mg pot^?1), indicating that the effects of S and EDTA on shoot metal concentration were more important than yield effects in determining rates of metal removal over the growth period of 50 days. Phytoextraction of Pb from this highly contaminated soil would require the growth of Indian mustard for nearly 100 years and is therefore impractical.     

Impaired Visual Integration in Children with Traumatic Brain Injury: An Observational Study

Background

Axonal injury after traumatic brain injury (TBI) may cause impaired sensory integration. We aim to determine the effects of childhood TBI on visual integration in relation to general neurocognitive functioning.

Methods

We compared children aged 6–13 diagnosed with TBI (n = 103; M = 1.7 years post-injury) to children with traumatic control (TC) injury (n = 44). Three TBI severity groups were distinguished: mild TBI without risk factors for complicated TBI (mild^RF- TBI, n = 22), mild TBI with ≥1 risk factor (mild^RF+ TBI, n = 46) or moderate/severe TBI (n = 35). An experimental paradigm measured speed and accuracy of goal-directed behavior depending on: (1) visual identification; (2) visual localization; or (3) both, measuring visual integration. Group-differences on reaction time (RT) or accuracy were tracked down to task strategy, visual processing efficiency and extra-decisional processes (e.g. response execution) using diffusion model analysis. General neurocognitive functioning was measured by a Wechsler Intelligence Scale short form.

Results

The TBI group had poorer accuracy of visual identification and visual integration than the TC group (Ps ≤ .03; ds ≤ -0.40). Analyses differentiating TBI severity revealed that visual identification accuracy was impaired in the moderate/severe TBI group (P = .05, d = -0.50) and that visual integration accuracy was impaired in the mild^RF+ TBI group and moderate/severe TBI group (Ps < .02, ds ≤ -0.56). Diffusion model analyses tracked impaired visual integration accuracy down to lower visual integration efficiency in the mild^RF+ TBI group and moderate/severe TBI group (Ps < .001, ds ≤ -0.73). Importantly, intelligence impairments observed in the TBI group (P = .009, d = -0.48) were statistically explained by visual integration efficiency (P = .002).

Conclusions

Children with mild^RF+ TBI or moderate/severe TBI have impaired visual integration efficiency, which may contribute to poorer general neurocognitive functioning.     

Effects of castration and home cage residency on aggressive behavior in rats

The effects of castration of both resident and intruder rats on territorial aggressive behavior were studied. The results suggest that residence in a home cage is more important than gonadal status in determining the outcome of an aggressive encounter. Resident rats were more likely to be dominant especially if they were intact. Intact residents directed less aggressive behavior toward castrated intruders than toward intact intruders. Intruder rats generally showed low levels of aggressive behavior and were only dominant when the resident had been castrated. Thus, the aggressive behavior of a male rat depends upon both his gonadal status and that of his opponent.