A highly conserved nuclear gene for low-level phylogenetics: elongation factor-1 alpha recovers morphology-based tree for heliothine moths

Molecular systematists need increased access to nuclear genes. Highly conserved, low copy number protein-encoding nuclear genes have attractive features for phylogenetic inference but have heretofore been applied mostly to very ancient divergences. By virtue of their synonymous substitutions, such genes should contain a wealth of information about lower-level taxonomic relationships as well, with the advantage that amino acid conservatism makes both alignment and primer definition straightforward. We tested this postulate for the elongation factor-1 alpha (EF-1 alpha) gene in the noctuid moth subfamily Heliothinae, which has probably diversified since the middle Tertiary. We sequenced 1,240 bp in 18 taxa representing heliothine groupings strongly supported by previous morphological and allozyme studies. The single most parsimonious gene tree and the neighbor-joining tree for all nucleotides show almost complete concordance with the morphological tree. Homoplasy and pairwise divergence levels are low, transition/transversion ratios are high, and phylogenetic information is spread evenly across gene regions. The EF-1 alpha gene and presumably other highly conserved genes hold much promise for phylogenetics of Tertiary age eukaryote groups.      

Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Effect of Nutrients on Growth Rate and Carbohydrate Storage in Oxytropis sericea: A Test of the Carbon Accumulation Hypothesis

The pool of storage carbohydrates in plants may be formed in competition with allocation to growth ("true reserves") or, where growth is inhibited by external factors, with no cost to growth ("accumulated reserves"). The latter hypothesis was addressed using Oxytropis sericea, a perennial herb from the Rocky Mountains. To generate variation in growth rate, greenhouse-cultivated plants were assigned to low or high nutrient levels in 2 yr. Age of plants was also varied either by conducting consecutive harvests (1996) or using plants of different initial age (1997). In both years, plants from the high-nutrient group attained larger vegetative biomass than plants in the low-nutrient group and also displayed an overall lower carbon allocation to storage, consistent with the accumulation hypothesis.     

Redundancy of stomatal control for the circadian photosynthetic rhythm in Kalanchoë daigremontiana Hamet et Perrier

In continuous light, the Crassulacean acid metabolism plant Kalanchoe daigremontiana Hamet et Perrier has a circadian rhythm of gas exchange with peaks occurring during the subjective night. The rhythm of gas exchange is coupled to a weak, reverse phased rhythm of quantum yield of photosystem II (Phi (PSII)). To test if the rhythm of Phi (PSII) persists in the absence of stomatal control, leaves were coated with a thin layer of translucent silicone grease which prevented CO2 and H2O exchange. In spite of this treatment, the rhythm of Phi (PSII) occurred with close to normal phase timing and with a much larger amplitude than in uncoated leaves. The mechanism underlying the Phi (PSII) rhythm in coated leaves can be explained by a circadian activity of phosphoenolpyruvate carboxylase (PEPC). At peaks of PEPC activity, the small amount of CO2 contained in the coated leaf could have become depleted, preventing the carboxylase activity of Rubisco and causing decreases in electron transport rates (observed as deep troughs of Phi (PSII) at 23-h in LL and at ca. 24-h intervals afterwards). Peaks of Phi (PSII) would be caused by a downregulation of PEPC leading to improved supply of CO2 to Rubisco. Substrate limitation of photochemistry at 23 h (trough of Phi (PSII)) was also suggested by the weak response of ETR in coated leaves to stepwise light enhancement. These results show that photosynthetic rhythmicity in K. daigremontiana is independent of stomatal regulation and may originate in the mesophyll.     

Carbohydrate storage and use in an alpine population of the perennial herb, Oxytropis sericea

I tested hypotheses for ecological roles of storage carbohydrates in perennating organs (roots and branches) of alpine Oxytropis sericea, a leguminous herb. In naturally growing plants, total nonstructural carbohydrates achieved their maximal concentration in the fall, declined during winter, and reached minimal levels immediately after growth initiation in the spring. Experimental manipulation of carbon sink-source relations through shading of leaves of reproductive plants revealed that the normally unused portion of these carbohydrates is largely available for withdrawal. In another experiment, plants subjected to carbohydrate depletion through shading suffered decreased leaf growth after winter dormancy and had a lower probability of flowering and decreased inflorescence biomass. The dependence of reproductive growth on stored carbohydrates, however, was limited to its initial stages, because accumulation of storage carbohydrates occurred simultaneously with inflorescence expansion, flowering, and fruiting. Moreover, the whole-plant photosynthetic rate, estimated from gas exchange measurements also peaked at the time of inflorescence growth. To address whether stored reserves allow compensatory regrowth following defoliation, plants were subjected to experimental removal of leaves and inflorescences. Defoliated O. sericea partly regrew the lost leaves but withdrawal of stored carbohydrates was limited. Similarly, in a second defoliation experiment where infructescences were left intact, the plants used little stored carbohydrate and only partly compensated for fruit growth. However, carbohydrate accumulation was negatively affected by defoliation. While the ecological importance of stored nonstructural carbohydrates cannot be attributed to any function in isolation, winter respiration, leaf regrowth after winter, and early reproductive growth in O. sericea all depend to a significant extent on stored reserves. Maintaining a large storage pool may protect these functions in years when carbon status is less favorable than during this study. Received: 13 May 1998 / Accepted: 24 November 1998     

A Two One-Sided Parametric Tolerance Interval Test for Control of Delivered Dose Uniformity—Part 2—Effect of Changing Parameters

This article examines the effects of changing parameters in the test which was proposed by the FDA at the October 2005 Advisory Committee meeting for confirming delivered dose uniformity in orally inhaled and nasal drug products. This article is an extension of the characterization study presented in an accompanying article (Part 1). The goal of this study is to understand how parameters of the test affect the test performance. The effects of changing test parameters such as target interval, maximum allowable proportion in the tail area, and sample size are examined. The results show that changing the maximum allowable tail area and/or the target interval have the largest impact on the test outcomes, i.e., probability of acceptance for a given batch mean and standard deviation. The presented information may provide potential users of the test with a set of tools for optimizing the test characteristics for a particular product.     

Stomatal density in Pinus sylvestris as an indicator of temperature rather than CO2: Evidence from a pan-European transect

The commonly observed negative relationship between stomatal density (SD) and atmospheric CO₂ has led to SD being proposed as an indicator of atmospheric CO₂ concentration. The use of SD as a proxy for CO₂, however, has been hampered by an insufficient understanding of the intraspecific variation of this trait. We hypothesized that SD in Pinus sylvestris, a widely distributed conifer, varies geographically and that this variation is determined by major climatic variables. By sampling needles from naturally growing trees along a latitudinal range of 32.25°, equivalent to 13.7°C gradient of mean annual temperature (MAT) across Europe, we found that SD decreased from the warmest southern sites to the coldest sites in the north at a rate of 4 stomata per mm² for each 1°C, with MAT explaining 44% of the variation. Additionally, samples from a provenance trial exhibited a positive relationship between SD and the MAT of the original localities, suggesting that high SD is an adaptation to warm temperature. Our study revealed one of the strongest intraspecific relationships between SD and climate in any woody species, supporting the utility of SD as a temperature, rather than direct CO₂, proxy. In addition, our results predict the response of SD to climate warming.     

Anatomical acclimation of mature leaves to increased irradiance in sycamore maple (Acer pseudoplatanus L.)

Photosynthesis Research - Trees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological...     

Product quality research institute evaluation of cascade impactor profiles of pharmaceutical aerosols, part 3: Final report on a statistical procedure for determining equivalence

The purpose of this article is to report final results of the evaluation of a chi-square ratio test proposed by the US Food and Drug Administration (FDA) for demonstrating equivalence of aerodynamic particle size distribution (APSD) profiles of nasal and orally inhaled drug products. A working group of the Product Quality Research Institute previously published results demonstrating some limitations of the proposed test. In an effort to overcome the test's limited discrimination, the group proposed a supplemental test, a population bioequivalence (PBE) test for impactor-sized mass (ISM). In this final report the group compares the chi-square ratio test to the ISM-PBE test and to the combination of both tests. The basis for comparison is a set of 55 realistic scenarios of cascade impactor data, which were evaluated for equivalence by the statistical tests and independently by the group members. In many instances, the combined application of these 2 tests appeared to increase the discriminating ability of the statistical procedure compared with the chi-square ratio test alone. In certain situations the chi-square ratio test alone was sufficient to determine equivalence of APSD profiles, while in other situations neither of the tests alone nor their combination was adequate. This report describes all of these scenarios and results. In the end, the group did not recommend a statistical test for APSD profile equivalence. The group did not investigate other in vitro tests, in vivo issues, or other statistical tests for APSD profile comparisons. The studied tests are not intended for routine quality control of APSD.     

Evidence for contractile protein translocation in macrophage spreading, phagocytosis, and phagolysosome formation

Macrophage pseudopodia that surround objects during phagocytosis contain a meshwork of actin filaments and exclude organelles. Between these pseudopodia at the base of developing phagosomes, the organelle exclusion ceases, and lysosomes enter the cell periphery to fuse with the phagosomes. Macrophages also extend hyaline pseudopodia on the surface of nylon wool fibers and secrete lysosomal enzymes into the extracellular medium instead of into phagosomes. To analyze biochemically these concurrent alterations in cytoplasmic architecture, we allowed rabbit lung macrophages to spread on nylon wool fibers and then subjected the adherent cells to shear. This procedure caused the selective release of β-glucoronidase into the extracellular medium and yielded two fractions, cell bodies and isolated pseudopod blebs resembling podosomes, which are plasma-lemma-bounded sacs of cortical cytoplasm. Cytoplasmic extracts of the cell bodies eluted from nylon fibers contained two-thirds less actin-binding protein and myosin, and approximately 20 percent less actin and two-thirds of the other two proteins were accounted for in podosomes. The alterations in protein composition correlated with assays of myosin-associated EDTA-activated adenosine triphosphatase activity, and with a diminution in the capacity of extracts of nylon wool fiber-treated cell bodies to gel, a property dependent on the interaction between actin-binding protein and F-actin. However, the capacity of the remaining actin in cell bodies to polymerize did not change. We propose that actin-binding protein and myosin are concentrated in the cell cortex and particularly in pseudopodia where prominent gelation and syneresis of actin occur. Actin in the regions from which actin-binding protein and myosin are displaced disaggregates without depolymerizing, permitting lysosomes to gain access to the plasmalemma. Translocation of contractile proteins could therefore account for the concomitant differences in organelle exclusion that characterize phagocytosis.