Comparative study of normal, Crouzon, and Apert craniofacial morphology using finite element scaling analysis

Finite element scaling analysis is used to study differences in morphology between the craniofacial complex of normal individuals and those affected with the syndromes of Apert and Crouzon. Finite element scaling quantifies the differences in shape and size between forms without reference to any fixed, arbitrary registration point or orientation line and measures the amount of form change required to deform one object into another. Two-dimensional coordinates of landmarks digitized from annual sets of cephalometric radiographs were used in the analysis. A simple tabulation shows no difference in variances between the normal and pathological samples. A test of mean differences depicts the Apert and Crouzon morphologies as significantly different from normal. The Apert palate differs from normal in shape in the older age groups analyzed, and palatal size differences are most common at the posterior nasal spine. The Apert pituitary fossa and basi-occiput are significantly larger than normal. The Crouzon pituitary fossa is also larger than normal, but the difference is not always significant. The typical morphology of the Crouzon nose is due more to differences in shape than size. The Crouzon basi-occiput is significantly smaller than normal. An age association of the differences between the normal and pathological craniofacies was found in Apert syndrome but not in Crouzon syndrome. Apert syndrome is characterized by a more homogeneous pattern of craniofacial dysmorphology from 6 months to 18 years of age than Crouzon syndrome.     

Immunocytochemical localisation of prolactin and growth hormone in the perinatal sheep pituitary

Summary The peroxidase anti-peroxidase immunocytochemical staining technique has been used to identify prolactin and growth hormone cells in pituitaries from fetal and neonatal sheep. The size of the secretory granules in these cell types has been measured using the image analysing computer Quantimet 720. The area size distributions of the fetal prolactin and growth hormone granules were compared with those in the neonate and the adult. It appears that the gestational age of the fetus may influence the size range of prolactin secretory granules.     

Consequences of fission in the coral <Emphasis Type="Italic">Siderastrea siderea</Emphasis>: growth rates of small colonies and clonal input to population structure

Colony age and size can be poorly related in scleractinian corals if colonies undergo fission to form smaller independent patches of living tissue (i.e., ramets), but the implications of this life-history characteristic are unclear. This study explored the ecological consequences of the potential discrepancy between size and age for a massive scleractinian, first by testing the effect of colony origin on the growth of small colonies, and second by quantifying the contribution of ramets to population structure. Using Siderastrea siderea in St. John (US Virgin Islands) as an experimental system, the analyses demonstrated that the growth of small colonies derived from sexual reproduction was 2.5-fold greater than that of small ramets which were estimated to be ≈100 years older based on the age of the parent colonies from which they split. Although fission can generate discrete colonies, which in the case of the study reef accounted for 42% of all colonies, it may depress colony success and reef accretion through lowered colony growth rates.     

Holotestoid: a computational model for testing hypotheses about echinoid skeleton form and growth

Regular echinoid skeletons, or tests, comprise plate patterns and overall shapes that have proven challenging to analyse solely on the basis of any one approach or process. Herein, we present a computational model, Holotestoid, that emulates four macrostructural ontogenic processes involved in test growth (plate growth, plate addition, plate interaction, and plate gapping). We devise a geometric representation for analysing tests and describe how we use analogies (bubble interactions and close-packing) to emulate the processes. In the computational model, the emulated processes are used to determine the plate size and plate shape and combined to simulate a growth zone. We simulated growth zones for Arbacia punctulata and for Strongylocentrotus franciscanus by changing the value for one parameter, the ambulacral column angle. We quantitatively compared morphological features for simulated forms to those for real specimens to test the computational model. Additionally, we simulated growth zones for A. punctulata, S. franciscanus, Eucidaris thouarsii, and Mellita quinquiesperforata by changing three parameters, ambulacral column angle, peristome radius to apical system radius ratio, and apical system radius to column length ratio. Holotestoid can be used to explain morphological disparity among echinoid tests.     

Genetic mapping of QTLs affecting tree growth and architecture in Populus: implication for ideotype breeding

 A segregated F₂ progeny derived from two highly divergent poplar species, Populus trichocarpa and P. deltoides, was used to evaluate the genetic basis of canopy structure and function in a clonally replicated plantation. The QTLs of large effect on growth, branch, and leaf traits were identified using the Populus linkage map constructed by 343 molecular markers. Stem height and harvest index appeared to be under the control of few QTLs with major effects, whereas variation in stem basal area, volume, and dry weight might be due to many more QTLs. Branch and leaf traits on sylleptics tended to include more QTLs with major effects than those on proleptics. In the environment where the pedigree was tested, sylleptics were very frequent in the P. trichocarpa parent but rare in the P. deltoides parent. For sylleptic traits for which two or more QTLs were identified, however, increases in the trait values were conditioned not only by the P. trichocarpa alleles, but also by the P. deltoides alleles. Similar findings were found for traits on proleptics that were differently expressed between the two parents. For both sylleptic and proleptic branch types, dominance (ranging from partial to over) was observed. The QTLs on specific linkage groups were found to be responsible for relationships between stem growth and its developmental components. Similar QTL clustering was also observed for morphological or developmental integration in poplar, i.e., traits with similar developmental origins are more strongly correlated with one another than traits with different developmental origins. The implications of these molecular genetic results for ideotype breeding of poplars are discussed. Received: 15 July 1997/Accepted: 19 August 1997     

Testing differences in relative growth rate: A method avoiding curve fitting and pairing

A method is discussed to test differences in relative growth rates. This method is based on an analysis of variance, with In-transformed plant weight as dependent variable. A significant Group × Time interaction indicates differences in relative growth rates between groups. The advantages over the "classical" and "functional" growth analyses are: (1) No pairing procedure is required. (2) More than two groups may be evaluated in one analysis. (3) No decision is required about the polynomial used to fit the data. (4) By partitioning the interaction effect using orthogonal polynomials insight is gained into the nature of differences in relative growth rate. (5) By concentrating attention on the lower order terms of the polynomials, the influence of extraneous variation on conclusions may be minimized.     

Plant growth analysis: towards a synthesis of the classical and the functional approach

A method of calculating relative growth rates (RGR) and net assimilation rates is presented. The method is based on the fitting of a polynomial through the relative growth rate values calculated by the 'classical' approach rather than through the In-transformed plant weights as in the 'functional' method. Additional ways of reducing the harvest-to-harvest variation characteristic of the classical approach are discussed. The main advantages of the present approach over the functional one are: (1) The degree of the polynomial can be increased (within certain limits) without inducing spurious fluctuations in RGR. Thus, quite complex trends in RGR can be described. (2) There is little interference between RGR values in different parts of the experiment. The main advantages over the classical approach are: (1) The erratic fluctuations in RGR are dampened. (2) As frequent small harvests are allowed, the workload at each harvest can be diminished and a more reliable impression of ontogenetic drift in RGR can be obtained. (3) RGR is described by a continuous function, thus facilitating further calculations and compilations.     

Factors affecting the reproductive success of the crab spider Misumenoides formosipes: the covariance between juvenile and adult traits

Summary To examine the importance of covariance between stages in traits related to foraging, we quantified the relationships between reproductive success and sizerelated variability in weight gain in juvenile and adult instars of the crab spider Misumenoides formosipes (Araneae: Thomisidae). Prereproductive weight and fecundity are both highly correlated with carapace width, a linear measure of size which does not change within an instar. In field populations, adult females with larger carapaces gain more weight and are more likely to reproduce than females with smaller carapaces. The growth rate of spiders fed ad libitum in the laboratory is unrelated to size, suggesting that size-related differences in the field are due to variation in prey-capture success. Adult females with a carapace width less than 3.4 mm comprised 22% of the population, but were never found to reproduce. Of the individuals that did reproduce, a 17% increase in carapace width resulted in a 100% increase in fecundity. Juvenile stages must be examined to understand adult foraging and reproductive success, because the net weight gained by juvenile instars determines adult size. The final weight gained by spiders in the antepenultimate and penultimate instars explained nearly all the variation in carapace width in the penultimate and adult instars, respectively. We found that constraints on foraging in late juvenile stages are different from the adult stage. Penultimate foraging behavior differs from that of adults, because of constraints on foraging in the period preceding ecdysis. Additionally, in both late juvenile instars, carapace width had little or no effect on the final weight gained within the instar suggesting that factors that affect foraging are different between the juvenile and adult stages. These analyses stress the fact that to fully understand the effects of foraging on reproductive success, we must examine stage-specific constraints throughout an organism's life history.     

Unpredictable environments,nuptial gifts and the evolution of sexual size dimorphism in insects: an experiment

Many insects have a mating system where males transfer nutrients to females at mating, which are often referred to as ''nuptial gifts''. Among butterflies, some of the characteristic features of these species are polyandry (females mate multiple times), and relatively large male ejaculates. When males produce part of the resources used for offspring, the value of body size might then increase for males and decrease for females. The male/female size ratio is also observed to increase when the degree of polyandry and gift size increase. Butterfly species where gift-giving occurs are generally more variable in body size, suggesting that food quality/quantity fluctuates during juvenile stages. This will cause some males to have much to provide and some females to be in great need, and could be conducive to the evolution of a gift-giving mating system. In such a system, growing male and female juveniles should react differently to food shortage. Females should react by maturing at a smaller size since their own lack of reproductive resources can partly be compensated for by male contributions. Males have to pay the full cost of decreased reproduction if they mature at a small size, making it more important for males to keep on growing, even when growth is costly. An earlier experiment with the polyandrous and gift-giving butterfly, Pieris napi, supported this prediction. The pattern is expected to be absent or reversed for species with small nuptial gifts, where females do not benefit from mating repeatedly, and will thus be dependent on acquiring resources for reproduction on their own. To test this prediction, we report here on an experiment with the speckled wood butterfly, Pararge aegeria. We find that growth response correlates with mating system in the two above species, and we conclude that differences in environmental conditions between species may act as an important factor in the evolution of the mating system and sexual size dimorphism.     

The lichen cushion: A functional perspective of color and size of a dominant growth form on glacier forelands

Mat-forming lichens dominating high-latitudinal habitats vary in color and geometry. Widespread species are light greenish yellow (usnic acid) and reflect solar radiation, whereas melanic species absorbing most solar wavelengths are spatially more restricted. Color thereby influences lichens’ energy budget and thus their hydration and photosynthetically active periods. By using well-defined cushions from early successional stages on glacier forelands – three melanic^(m) and three usnic^(u) mat-forming lichens with hair-like branches (Alectoria ochroleuca^(u), Gowardia nigricans^(m)), hollow terete branches (Cladonia uncialis^(u), Cetraria muricata^(m)), and flat branches (Flavocetraria nivalis^(u), Cetraria islandica^(m)) – we quantified hydration traits and analyzed how color and cushion size affect water loss rate (WLR) and duration of active periods. Main findings: 1) WLR declined with cushion size and was highest in melanic lichens. 2) Active periods were longer for usnic than for melanic lichens and increased with size in all groups. 3) Size, color, and taxon nested in color significantly influenced WLR and duration of active periods in linear mixed models. 4) Hair lichen cushions had shorter active periods than growth forms with terete or flat branches due to their more open canopy architecture and lower water holding capacity (WHC). 5) WHC measured for isolated branches highly underestimated WHC for intact cushions.     

Age and growth studies of chondrichthyan fishes: the need for consistency in terminology, verification, validation, and growth function fitting

Validated age and growth estimates are important for constructing age-structured population dynamic models of chondrichthyan fishes, especially those which are exploited. We review age and growth studies of chondrichthyan fishes, using 28 recent studies to identify areas where improvements can be made in describing the characteristics of ageing structures (both traditional and novel) utilized to estimate ages of sharks, rays, and chimaeras. The topics identified that need consistency include the: (1) terminology used to describe growth features; (2) methods used to both verify and validate age estimates from chondrichthyan calcified structures, especially edge and marginal increment analyses; and (3) the functions used to produce and describe growth parameters, stressing the incorporation of size at birth (L ₀) and multiple functions to characterize growth characteristics, age at maturity and longevity.     

Changes in skull components of the squirrel monkey evoked by growth and nutrition: an experimental study

Twenty weanling 6-month-old male squirrel monkeys were allotted to the following treatments: 1) first control animals were killed at weaning; 2) second control animals were killed when 24 months old; and 3) malnourished animals were fed on a low-protein diet and killed at age 24 months. Lateral and vertical teleradiographies were taken. Growth of the neurocranial and splanchnocranial components were measured by volumetric (size estimators) and morphometric (shape estimators) indices. All facial components grew. The neurocranial components showed a heterogeneous behavior: The anteroneural component remained stable, and the increase of the midneural component was compensated by a decrease in the posteroneural component. Malnutrition affected the growths of 1) the craniofacial complex, 2) the splanchnocranium, and 3) the respiratory and midneural components. Growth influenced skull shape through 1) increases of the splanchnocranium and the midneural component relative to the neurocranium; 2) decreases of the masticatory and optic components relative to the splanchnocranium, and 3) decreases of the anteroneural and posteroneural components relative to the neurocranium. Malnutrition influenced skull shape through the relationship between the anteroneural component and the neurocranium. These results confirmed the existence of functional interrelationships among the cranial components. A new approach to craniological studies is suggested.     

The utilization of lightflecks for growth in four Australian rain-forest species

1. The ability of rain-forest plants to utilize sunflecks for growth was investigated using the following species: Alocasia macrorrhiza, Diploglottis diphyllostegia, Micromelum minutum and Omalanthus novo-guinensis.
2. Growth analysis and gas-exchange measurements were used to assess performance of the four species when exposed to either constant or fluctuating light.
3. Final biomass (g dry wt) in D. diphyllostegia and M. minutum grown under the lightfleck regime (total daily PFD = 7·02 mol m^–2 day^–1) was significantly greater than in the same species grown under constant low PFD (total daily PFD = 4·86 mol m^–2 day^–1). In contrast, final biomass in lightfleck O. novo-guinensis and A. macrorrhiza was significantly reduced in comparison with the same species grown under constant low PFD.
4. When grown under either constant or fluctuating light but with the same total daily PFD, A. macrorrhiza and O. novo-guinensis had significantly lower final biomass in fluctuating light as compared to constant light. Final biomass in D. diphyllostegia was not significantly different in either regime, while M. minutum had significantly higher final biomass in the fluctuating light regime.
5. Responses of the four species to fluctuating or constant light appeared to be the result of physiological rather than morphological acclimation as net assimilation rate was more closely correlated with relative growth rate than was leaf area ratio.     

The first study of human growth: Christian Friedrich Jampert

The circumstances surrounding the first study of human growth, published in 1754, are described. Jampert, who made this study, died young and his work was not recognised, indeed remained completely unknown between 1778 and 1981. The content of the work is briefly described.     

A method for the study of fungal growth inhibition by plant proteins

A bioassay is described for the study of inhibitory activity of plant proteins on fungal growth. Fungal spores were germinated in liquid growth medium and pipetted into wells of a microtitre plate. Fungal growth was followed spectrophotometrically. The bioassay was tested using crude protein extracts from plant tissues known to have high activities of chitinase and beta-1,3-glucanase, and with purified enzymes. Crude protein preparations and combinations of the purified enzymes produced a temporary reduction of growth but no permanent growth inhibition.     

Growth of food-borne pathogenic bacteria in oil-in-water emulsions: I—Methods for investigating the form of growth

Methods are presented for investigating the site and form of growth of bacteria in model oil-in-water emulsions and in dairy cream. Following growth of the bacteria, the continuous aqueous phase is gelled using agarose and the oil phase removed using a mixture of chloroform and methanol. Using this method, the authors have found that Listeria monocytogenes, Salmonella typhimurium and Yersinia enterocolitica grow in the form of colonies in concentrated oil-in-water emulsions. Colonies of L. monocytogenes and Y. enterocolitica also form in artificially-inoculated fresh and tinned dairy cream. If information about the precise site of growth is not required, the authors have discovered that intact colonies can be liberated from the model emulsions by dissolving away the oil phase with chloroform: methanol.