A model including photoperiod in degree days for estimating Hevea bud growth

 The aim of this study was to verify the applicability of a heat-sum model and an alternative model that included photoperiod to describe Hevea bud growth. Considering 19° C as the base temperature, approx. 172 degree days were required for bud growth up to leaf blade expansion. The applicability of the heat-sum model for Hevea bud growth was confirmed. The inclusion of day length as an exponential term in accumulated degree days resulted in the model fitting much better for the spring than for the winter conditions. Received: 21 May 1995 / Revised: 28 October 1996 / Accepted: 27 January 1997     

Evolutionary Phycology: Toward a Macroalgal Species Conceptual Framework

Species concepts formalize evolutionary and ecological processes, but often conflict with one another when considering the mechanisms that ultimately lead to species delimitation. Evolutionary biologists are, however, recognizing that the conceptualization of a species is separate and distinct from the delimitation of species. Indeed, if species are generally defined as separately evolving metapopulation lineages, then characteristics, such as reproductive isolation or monophyly, can be used as evidence of lineage separation and no longer conflict with the conceptualization of a species. However, little of this discussion has addressed the formalization of this evolutionary conceptual framework for macroalgal species. This may be due to the complexity and variation found in macroalgal life cycles. While macroalgal mating system variation and patterns of hybridization and introgression have been identified, complex algal life cycles generate unique eco-evolutionary consequences. Moreover, the discovery of frequent macroalgal cryptic speciation has not been accompanied by the study of the evolutionary ecology of those lineages, and, thus, an understanding of the mechanisms underlying such rampant speciation remain elusive. In this perspective, we aim to further the discussion and interest in species concepts and speciation processes in macroalgae. We propose a conceptual framework to enable phycological researchers and students alike to portray these processes in a manner consistent with dialogue at the forefront of evolutionary biology. We define a macroalgal species as an independently evolving metapopulation lineage, whereby we can test for reproductive isolation or the occupation of distinct adaptive zones, among other mechanisms, as secondary lines of supporting evidence.     

Mechanical response to methacholine and deep inspiration in supine men.

The effects of supine posture on airway responses to inhaled methacholine and deep inspiration (DI) were studied in seven male volunteers. On a control day, subjects were in a seated position during both methacholine inhalation and lung function measurements. On a second occasion, the whole procedure was repeated with the subjects lying supine for the entire duration of the study. On a third occasion, methacholine was inhaled from the seated position and measurements were taken in a supine position. Finally, on a fourth occasion, methacholine was inhaled from the supine position and measurements were taken in the seated position. Going from sitting to supine position, the functional residual capacity decreased by approximately 1 liter in all subjects. When lung function measurements (pulmonary resistance, dynamic elastance, residual volume, and maximal flows) were taken in supine position, the response to methacholine was greater than at control, and this was associated with a greater dyspnea and a faster recovery of dynamic elastance after DI. By contrast, when methacholine was inhaled in supine position but measurements were taken in sitting position, the response to methacholine was similar to control day. These findings document the potential of the decrease in the operational lung volumes in eliciting or sustaining airflow obstruction in nocturnal asthma. It is speculated that the exaggerated response to methacholine in the supine posture may variably contribute to airway smooth muscle adaptation to short length, airway wall edema, and faster airway renarrowing after a large inflation.     

Base temperature and heat units for leaf flushing emission and growth ofHevea brasiliensis Muell. Arg.

In this study we determined the base temperature and Heat units for leaf flushing initiation and growth of RRIM-600 and GT1Hevea clones. The minimum base temperature was found to be approximately 16° C for leaf flushing emission and 19° C for shoot growth in terms of height. Approximately 420 degree days at 16° C as base temperature is required for successive leaf flushing initiation. Linear equations with correlation coefficients above 0.95 allow an estimation of the height increase from the accumulated degree days, corrected or otherwise for photoperiod. The highest correlation coefficients demonstrated a positive effect of the photoperiod among the factors influencing the shoot growth.     

Direct Detection of Unnatural DNA Nucleotides dNaM and d5SICS using the MspA Nanopore

Malyshev et al. showed that the four-letter genetic code within a living organism could be expanded to include the unnatural DNA bases dNaM and d5SICS. However, verification and detection of these unnatural bases in DNA requires new sequencing techniques. Here we provide proof of concept detection of dNaM and d5SICS in DNA oligomers via nanopore sequencing using the nanopore MspA. We find that both phi29 DNA polymerase and Hel308 helicase are capable of controlling the motion of DNA containing dNaM and d5SICS through the pore and that single reads are sufficient to detect the presence and location of dNaM and d5SICS within single molecules.     

Three New Species of Curtara (Homoptera: Cicadellidae: Gyponinae) from Brazil

Three new species of the leafhopper genus Curtara DeLong & Freytag, 1972, C. mejdalanii spec. nov., C. maricaensis spec. nov., and C. restingalis spec. nov., are described from Rio de Janeiro State, Brazil. They belong to the Notanda group of the subgenus Curtara because of the presence of only two subapical processes in the aedeagal shaft. C. mejdalanii spec. nov. seems to be more closely related to C. rugara DeLong & Freytag, 1976 because of the shape of the subapical aedeagal processes but differs from it by the enlarged apical area of the aedeagus, the absence of ventral pre-apical saliency of style, the rounder apex of the subgenital plate, and the longer pygofer, with a fold accompanying the whole lateral margin. C. maricaensis spec. nov. and C. restingalis spec. nov. seem to be closely related to C. esona DeLong & Freytag, 1976, as suggested by the general shape of internal genital parts, but differ from it by the shape of the apex of basal processes of the aedeagus, the apex of subgenital plates and the absence of an outer fold on the ventral margin of the pygofer.