Iridoid glucosides in fouquieriaceae

From three Fouquieria sp. 12 iridoid glucosides were isolated and identified. Eight of these were structurally related to galioside (monotropein methylester), while four were hydroxy substitution products of deoxyloganin. In three cases the glucoside occurred together with the corresponding 10-O-acetate.     

Untangling spider silk evolution with spidroin terminal domains

Background  

Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C)-terminal domains, though they offer limited character data. The few known spidroin amino (N)-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs) from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains.     

Biological effects of D2O administration to Coturnix japonica

Levels of 7.8, 18.5 and 26 mole % deuterium oxide were administered sequentially to $\text{Coturnix japonica}$ (Japanese quail) via the drinking water. The primary effect observed was on egg frequency, which decreased from a normal level of 0.89 for 7.8 mole % D₂O to a low of 0.38 during the administration of 26 mole % D₂O. Adverse symptoms, such as hyperexcitability, convulsions, skin ulcerations, comatosity, weight loss, or death, which have been associated with deuterium toxicity in other animals, were not observed in these experiments. The amount of deuterium deposited in the water of the egg was 6.9, 13.98, and 19.83 mole % when 7.8, 18.5 and 26 mole % deuterium respectively was administered. For each period, the deuterium content of egg water rapidly reached a maximum concentration after which the concentration decreased slightly. This dilution effect has not been noted previously in body fluids from other animals.     

Relationship between postabsorptive respiratory exchange ratio and plasma free fatty acid concentrations

The relationship between overnight postabsorptive (fasting) respiratory exchange ratio (RER) and plasma FFA concentrations was addressed using data from three separate protocols, each of which involved careful control of the antecedent diet. Protocol 1 examined the relationship between fasting RER and the previous daytime RER. In Protocol 2 fasting, RER and plasma palmitate concentrations were measured in 29 women and 31 men (body mass index <30 kg·m⁻²). Protocol 3 analyzed data from Nielsen et al. (Nielsen, S., Z. K. Guo, J. B. Albu, S. Klein, P. C. O''Brien, M. D. Jensen. 2003. Energy expenditure, sex and endogenous fuel availability in humans. J. Clin. Invest. 111: 981-988.) to understand how fasting RER and palmitate concentrations relate within individuals during four consecutive measurements. The results were as follows: 1) Fasting RER was correlated (r = 0.74, P < 0.001) with the previous day''s average RER, and less so with RER variability. 2) Fasting RER was correlated (r = −0.39, P = 0.007) with fasting plasma palmitate concentrations. 3) The pattern of the RER/palmitate relationship was similar within individuals and between individuals; a negative slope was observed significantly more often than a positive slope (χ² test; P < 0.001). Our findings suggest that, despite a fixed food quotient, the slight departures from energy equilibrium in a controlled General Clinical Research Center environment can effect plasma FFA concentrations. We suggest that including indirect calorimetry as part of FFA metabolism studies may aid in data interpretation.     

Losing the last feather: feather loss as an antipredator adaptation in birds

Birds often lose feathers during predation attempts, and thisability has evolved as a means of escape. Because predatorsare more likely to grab feathers on the rump and the back thanon the ventral side of an escaping bird, we predicted that theformer feathers would have evolved to be relatively looselyattached as an antipredator strategy in species that frequentlydie from predation. We estimated the force required to removefeathers from the rump, back, and breast by pulling featherswith a spring balance from a range of European bird speciesin an attempt to investigate ecological factors associated withease of feather loss during predation attempts. The force requiredto loosen a feather from the rump was less than that requiredto loosen a feather from back, which in turn was less than thatrequired to loosen a feather from the breast. The relative forceneeded to loosen rump feathers compared with feathers from theback and the breast was smaller for prey species preferred bythe most common predator of small passerine birds, the sparrowhawkAccipiter nisus. Likewise, the relative force was also smallerin species with a high frequency of complete tail loss amongfree-living birds, which we used as an index of the frequencyof failed predation attempts. The relative force required toremove feathers from the rump was smaller in species with ahigh frequency of fear screams, another measure of the relativeimportance of predation as a cause of death. Feather loss requiredparticularly little force among solitarily breeding bird speciesthat suffer the highest degree of predation. Antipredator defensein terms of force required to remove feathers from the rumpwas larger in species with a strong antiparasite defense interms of T-cell–mediated immune response. These findingsare consistent with the hypothesis that different defenses areantagonistic and that they are traded off against each other.     

Typing of Genetic Markers Involved in Stress Response by Fluorescent cDNA-Amplified Fragment Length Polymorphism Technique

Identification of genetic markers involved in stress response to physical factors or chemical substances in organisms is a challenging task. Typing of upregulated gene expression due to selective antibacterial pressure is a promising approach in the search of molecular mechanisms responsible for development of resistance. cDNA-Fluorescent Amplified Fragment Length Polymorphism (cDNA-FAFLP) strategy was developed and applied in the search of antimycotic drug resistance marker(s) in medically important fungi as an alternative method to microarray analysis. We compared differential gene expression of two sensitive Candida albicans reference strains (ATCC 10231 and ATCC 60133) and two of their paired resistant to fluconazole and itraconazole mutants. Resistant mutants Candida albicans FLC-R, resistant to fluconazole (MIC > 128 μg/ml) and Candida albicans ICZ-R, resistant to itraconazole (MIC > 4 μg/ml) were obtained in subcultures with gradual increase of the antifungal in the culture medium. cDNA-AFLP profile in both itraconazole resistant mutants showed specific spectrophotometric peaks with 5–6-fold RNA overexpression product of 500 bp length compared to the sensitive strains. Fluconazole mutants do not reveal RNA level changes under tested by us typing conditions. These results indicate that the cDNA-FAFLP strategy is a relatively rapid, simple, and reliable method for simultaneous typing of both constitutive and induced differences in expression of host genes providing insight into the biological processes involved in response to drugs in bacteria and fungi. Moreover, this methodology could be tested for typing of the genome response of any organism to physical or chemical stress factors.     

Physical and chemical variability in sugarcane fields infested with the red-striped soft scale insect,Pulvinaria Tenuivalvata (Newstead)

The red-striped soft scale insect Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae) started to infest sugarcane plants (Saccharum officinarum L.) in different districts in Egypt during the last decade. The percentage of infestation was recorded in El-Wakf area, Qena Governorate (Naghhamadi mill zone) Upper Egypt in some fields. There are three levels of infestation, low, intermediate and high. From these fields, samples were selected for physical and chemical studies. The results obtained show that the stalks of infested plants decreased in weight, the sugar content (glucose and sucrose) drastically reduced and as the percentage of infestation increased the percentage of glucose and sucrose content significantly decreased. The primary and secondary humidity and the cellulose content also increased in the healthy plants compared to the infested ones. All the physical character of the infested plants was significantly affected in comparison with the healthy ones.