Flight in Ground Effect Dramatically Reduces Aerodynamic Costs in Bats

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CAEV Infection does not Affect Prevalence of Bacterial Mastitis in Goats

Like other lentiviruses, caprine arthritis-encephalitis virus (CAEV) causes persistent infection. The majority of CAEV-infected goats is clinically healthy. Signs of disease are associated with progressive inflammation in one or more organ or tissue systems such as joints, bursae, brain, spinal cord, lungs, and udder (Bulgin 1990, Dawson 1987). In most CAEV- infected females, the mammary gland, which is a target for the virus, is likely to be infected (Kennedy-Stoskopf et al. 1985, Lerondelle et al. 1989). The infection may cause increased somatic cell counts (Post et al. 1984, Nord & Adnoy to be published). The milk mostly appears normal and mastitis may not be suspected. Ryan et al. (1993) and Smith & Cutlip (1988) suggested that susceptibility to bacterial udder infection is enhanced in CAEV-infected goats, in particular with regard to infections due to non-haemolytic Staphylococci. In this study, the prevalence of bacterial udder infections in CAEV-antibody positive goats is compared with that in negative animals.     

Pancreatic cancer risk in relation to sex,lifestyle factors,and pre-diagnostic anthropometry in the Malmö Diet and Cancer Study

Background

Lifestyle factors may influence the risk of developing pancreatic cancer. Whereas cigarette smoking is an established risk factor, the effects of high alcohol intake and obesity are more uncertain. The aim of the present study was to examine the associations of pre-diagnostic anthropometry, alcohol consumption, and smoking habits with pancreatic cancer risk in a Swedish prospective, population-based cohort, with particular reference to potential sex differences.

Methods

The studied cohort consists of 28,098 participants, including all incident cases of pancreatic cancer, in the Malmö Diet and Cancer Study up until December 31, 2013 (n?=?163). Non-parametric and chi-squared tests were applied to compare the distribution of risk factors between cases and non-cases. Cox regression proportional hazards models were used to estimate the relationship between investigative factors and pancreatic cancer risk. Anthropometric factors included height, weight, body mass index (BMI), waist and hip circumference, waist-hip ratio (WHR), and body fat percentage.

Results

BMI was not a significant risk factor for pancreatic cancer, but a higher WHR was significantly associated with an increased risk in the entire cohort (hazard ratio (HR) 2.36, 95% confidence interval (CI) 1.28–4.35, p for trend?=?0.009). Regular smoking was a significant risk factor among both women (HR 2.62, 95% CI 1.61–4.27) and men (HR 3.57, 95% CI 1.70–7.47), whereas occasional smoking was a significant risk factor only in women (HR 3.29, 95% CI 1.50–7.19). Passive smoking at work for >20 years was significantly associated with an increased risk in the entire cohort (HR 1.73, 95% CI 1.15–2.58) and in women selectively (HR 2.01, 95% CI 1.21–3.31). Alcohol consumption was not a significant risk factor. A significant interaction was found between female sex and age (p?=?0.045), but no other factor, in relation to pancreatic cancer risk.

Conclusions

WHR was the only pre-diagnostic anthropometric factor associated with pancreatic cancer risk, with no sex-related differences. Regular smoking was confirmed as a significant risk factor in both sexes, whereas occasional and passive smoking were significant risk factors only in women. Despite the lack of a significant interaction between smoking and sex in relation with pancreatic cancer risk, potential sex differences should be considered in future epidemiological studies.

     

Mind the wind: microclimate effects on incubation effort of an arctic seabird

The energetic costs of reproduction in birds strongly depend on the climate experienced during incubation. Climate change and increasing frequency of extreme weather events may severely affect these costs, especially for species incubating in extreme environments. In this 3‐year study, we used an experimental approach to investigate the effects of microclimate and nest shelter on the incubation effort of female common eiders (Somateria mollissima) in a wild Arctic population. We added artificial shelters to a random selection of nesting females, and compared incubation effort, measured as body mass loss during incubation, between females with and without shelter. Nonsheltered females had a higher incubation effort than females with artificial shelters. In nonsheltered females, higher wind speeds increased the incubation effort, while artificially sheltered females experienced no effect of wind. Although increasing ambient temperatures tended to decrease incubation effort, this effect was negligible in the absence of wind. Humidity had no marked effect on incubation effort. This study clearly displays the direct effect of a climatic variable on an important aspect of avian life‐history. By showing that increasing wind speed counteracts the energetic benefits of a rising ambient temperature, we were able to demonstrate that a climatic variable other than temperature may also affect wild populations and need to be taken into account when predicting the effects of climate change.     

A urinary pentasaccharide in bovine mannosidosis.

Abnormally high amounts of low molecular weight mannose-rich carbohydrate material were found in the urine of an Angus calf with mannosidosis. At least five oligosaccharide fractions were detected by paper chromatography. The most abundant compound was purified by gel chromatography, zone electrophoresis, and two consecutive preparative paper chromatographic steps. The yield was 10 mg/liter of urine. From structural studies including nuclear magnetic resonance spectroscopy, optical rotation, sugar analysis, methylation analysis, and partial enzymatic degradation the following structure was deduced: alpha-D-Manp-(1 leads to 6)-beta-D-Manp-(1 leads to 4)-beta-D-GlcNAcp-(1 leads to 4)-beta-D-GlcNAcp-(1 leads to 4)-D-GlcNAc. This oligosaccharide is distinct from all the oligosaccharides previously described which are excreted by patients with mannosidosis.     

On the use of chiral compounds for probing the DNA handedness: Z to B conversion in poly(dGm5dC) upon binding of Fe(phen)3(2+) and Ru(phen)3(2+)

In order to examine whether chiral metal complexes can be used to discriminate between right- and left-handed DNA conformational states we have studied the enantioselective interactions of Fe(phen)3(2+) and Ru(phen)3(2+) (phen = 1,10-phenanthroline) with poly(dGm5dC) under B- and Z-form conditions. With the inversion-labile Fe(phen)3(2+), enantioselectivity leads to shifts in the diastereomeric binding equilibria. This effect, known as the "Pfeiffer effect" (1-4), is monitored as slowly emerging circular dichroism of the solution, corresponding to a net excess of the favoured enantiomer. With Ru(phen)3(2+), which is stable to intramolecular inversion, the difference in DNA-binding strengths of the enantiomers results in an excess of the less favoured enantiomer in the bulk solution. This excess is detected in the dialysate of the DNA/metal complex solution. With both complexes we find that the delta-enantiomer is favoured when the polynucleotide adopts the B-form, as previously shown, but also when it initially adopts the Z-form conformational state. This observation, together with evidence from UV-circular dichroism and binding data, indicates that the binding of these metal complexes induces a Z- to B-form transition in Z-form poly(dGm5dC). Consequently, neither of the studied chiral DNA-binders can easily be used to discriminate the DNA handedness.     

Binding geometries of benzo[a]pyrene diol epoxide isomers covalently bound to DNA. Orientational distribution

Flow linear dichroism (LD) of different benzo[a]pyrene diol epoxide (BPDE) isomers covalently bound to calf thymus DNA or poly(dG-dC) provides information about binding geometry and DNA perturbation. With anti-BPDE the apparent angle between the long axis (z) of the pyrene chromophore and the DNA helix axis is approximately 30 degrees as evidenced from the LD of z-polarized absorption bands in the pyrenyl chromophore at 252 and 346 nm. The corresponding angle for the in-plane short axis (y) is determined to be approximately 70 degrees from a y-polarized band at 275 nm. The binding of (+)-anti-BPDE to DNA is found to cause a considerable reduction of the DNA orientation. This is ascribed to a decreased persistence length of DNA, owing either to increased flexibility ("flexible joints") or to permanent kinks at the points of binding. The reduced linear dichroism (LDr), i.e., the ratio between LD and isotropic absorbance, of the long-wavelength absorption band system of BPDE bound to DNA exhibits a wavelength dependence that indicates a relatively wide orientational distribution of the z axis of pyrene. Fluorescence data support the conclusion of a heterogeneous distribution, and a very low polarization anisotropy indicates a mobility between the different orientational states, which is rapid compared to the fluorescence lifetime (nanosecond time scale). Attempts are made to simulate the observed LDr features of the (+)-anti-BPDE-poly(dG-dC) complex using different distribution models on the assumption that the angular dependence of the spectral perturbation is due to dispersive interactions with DNA bases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of proteolysis of the extending parts of the high-molecular-weight microtubule-associated proteins on interactions between microtubules

Digestion of assembled microtubules with agarose-bound trypsin was performed to obtain microtubules which lack the extending projections, the non-tubulin-binding part of the high-molecular-weight microtubule-associated proteins. The assembly kinetics and the minimum protein concentration for assembly were the same for these trypsinated microtubules as for normal, untreated microtubules. Furthermore, the digested microtubules gave rise to the same change in turbidity per polymer mass as that found for normal microtubules. However, electron microscopy of pelleted microtubules revealed a closer packing after trypsin treatment. A substantially lower increase in specific viscosity was found upon assembly. At concentrations of above approx. 1.5 mg/ml, the viscosity of trypsin-treated microtubules was almost independent of the protein concentration, in contrast to the turbidity, which still increased. Both microtubules and the trypsin-digested microtubules were easily oriented by shear, although the flow linear dichroism signal for the microtubules after trypsin treatment was only half of that found for perfectly oriented normal microtubules. At higher shear force gradients, digested microtubules aggregated side by side as shown by electron microscopy. This was not found for normal microtubules. Even although the extending parts of the high-molecular-weight proteins are not needed for assembly, they were found to play an important role in microtubule orientation and interactions between microtubules, probably by acting as spacers between microtubules.     

High mutagenic activity formed in pan-broiled pork

Lean pork was pan-broiled at various temperatures between 100 and 290 degrees C. Cooking was performed in an open frying pan common for domestic use in Sweden. No fat was added. Cooking procedures are clearly defined in order to facilitate inter-laboratory comparisons. The crust was extracted with organic solvents of varying polarity. The mutagenic activity was assayed with Ames' Salmonella mutagenicity test. Large amounts of mutagenic activity were detected in samples pan-broiled at 200-290 degrees C. The mutagenic activity recovered was about 10 times higher than that reported by previous investigators to be found during cooking of meat under similar conditions. This discrepancy could be due to differences in the composition of Swedish pork as compared to the meat samples used by other investigators or to different methodology in cooking and extraction procedures.