High prevalence of cerebral venous sinus thrombosis (CVST) as presentation of cystathionine beta-synthase deficiency in childhood: Molecular and clinical findings of Turkish probands

Classical homocystinuria is the most commonly inherited disorder of sulfur metabolism, caused by the genetic alterations in human cystathionine beta-synthase (CBS) gene. In this study, we present comprehensive clinical findings and the genetic basis of homocystinuria in a cohort of Turkish patients. Excluding some CBS mutations, detailed genotype–phenotype correlation for different CBS mutations has not been established in literature. We aimed to make clinical subgroups according to main clinical symptoms and discussed these data together with mutational analysis results from our patients. Totally, 16 different mutations were identified; twelve of which had already been reported, and four are novel (p.N93Y, p.L251P, p.D281V and c.829−2A>T). The probands were classified into three major groups according to the clinical symptoms caused by these mutations. A psychomotor delay was the most common diagnostic symptom (n = 12, 46.2% neurological presentation), followed by thromboembolic events (n = 6, 23.1% vascular presentation) and lens ectopia, myopia or marfanoid features (n = 5, 19.2% connective tissue presentation). Pyridoxine responsiveness was 7.7%; however, with partial responsive probands, the ratio was 53.9%.     

Statistical estimators of frontal sinus cross section ontogeny from very noisy data

Cross-sectional areas of human frontal sinuses in the occipitofrontal projection are a good surrogate for frontal sinus volumes. This study looks at these areas in a dataset of some 200 children and 100 adults of both sexes. As measured by planimetry of roentgenograms, the areas are extremely variable ("noisy" in a statistical sense). In fact, they appear to be distributed log-normally with quite high variance. The mean of the distribution is evidently a function of age and the variances differ by sex. After logarithmic transformation, the data are adequately fitted by one sigmoid curve for each sex. Our discussion highlights implications of this finding for the biological aspects of frontal sinuses and methodological issues in ontogenetic analysis of data so noisy.     

Lack of definition of mathematical terms in ecology: The case of the sigmoid class of functions in macro‐ecology

Defining mathematical terms and objects is a constant issue in ecology; often definitions are absent, erroneous, or imprecise. Through a bibliographic prospection, we show that this problem appears in macro‐ecology (biogeography and community ecology) where the lack of definition for the sigmoid class of functions results in difficulties of interpretation and communication. In order to solve this problem and to help harmonize papers that use sigmoid functions in ecology, herein we propose a comprehensive definition of these mathematical objects. In addition, to facilitate their use, we classified the functions often used in the ecological literature, specifying the constraints on the parameters for the function to be defined and the curve shape to be sigmoidal. Finally, we interpreted the different properties of the functions induced by the definition through ecological hypotheses in order to support and explain the interest of such functions in ecology and more precisely in biogeography.     

Modelling cacao pod growth: implications for disease control

Cacao trees are affected by diseases that attack either their vegetative parts, their fruits or both. In cacao pod diseases, several factors are involved in disease susceptibility, such as the fruiting cycle, fruit size, age, position on the tree and cacao genotype. To gain a clearer understanding of how these characteristics influence cacao pod diseases, four models describing pod growth in several cacao genotypes were evaluated. Three models used to estimate pod volume or surface area were also compared. Observed pod growth was of a sigmoid form and fitted best to the Richards model, well to the Logistic and Beta growth models, and least to the Gompertz model. Pod volume and probably pod surface area were best estimated using a prolate spheroid model. Pod growth models can help improve pod disease management and thereby cacao production. They can help to predict yield, as well as provide information for the timing and frequency of control operations. Information on pod size, surface area and susceptibility will help to improve dose transfer and spray deposit studies intended to optimise control efficiency.     

Why do rotifer populations present a typical sigmoid growth curve?

To determine the underlying processes to population growth in the rotifer Brachionus plicatilis, we conducted an experiment using 1.5 ml cultures for 70 days. All individuals were transferred daily to culture media containing algae, and the number of individuals, clutch sizes and number of deaths were counted. The population dynamics showed a typical sigmoid curve. The population density increased exponentially from 10 to 682 individuals during the first 7 days (exponential growth phase), and gradually up to about 1500 individuals during the next 30 days (post-exponential growth phase). The population density then remained at a constant level with small fluctuations during the rest of the experimental period (stationary phase). Mortalities appeared from the post-exponential growth phase and were almost constant at about 2% throughout the experimental period. The clutch size decreased from 5 to 1 during the first 5 days, and afterwards females laid only one egg each. The proportion of non-reproductive females increased from 30% (exponential growth phase) to 80% (post-exponential growth phase) to 90% (stationary phase). These results suggest that the exponential growth phase resulted from the imbalance between a high birth rate and a low death rate, while the stationary phase was maintained by the compensation between low birth and death rates.     

Silica accumulation in long-lived leaves of Sasa veitchii (Carrière) Rehder (Poaceae-Bambusoideae)

Silica accumulation in long-lived leaves of Sasa veitchii was investigated using the molybdenum blue method. In general, silica accumulation was rapid during spring and summer, and slow during winter. The leaves continuously accumulate silica throughout their life. The significance of these observations is discussed in relation to two hypotheses for silica accumulation in plants: (1) that silica accumulation is a result of water consumption by the plant: and (2) that silica is actively accumulated to protect the plant. The results of the present study support the former hypothesis.     

Strategic exploitation of fluctuating asymmetry in male Endler's guppy courtship displays is modulated by social environment

Lateral asymmetry in signalling traits enables males to strategically exploit their best side. In many animals, both body colouration and fluctuating asymmetry are signals of male attractiveness. We demonstrated experimentally that even sexually naïve male Poecilia wingei were able to identify their most attractive side (i.e. that with a higher proportion of carotenoid pigmentation) and use it preferentially during courtship. Notably, males retained their strategic signalling in a male‐biased social environment, whereas they ceased to signal strategically in a female‐biased environment. The degree of asymmetry in colouration did not affect overall courtship activity. Strategic lateralization in courtship displays was strongest and most repeatable in the male‐biased social environment where males competed with rivals for matings. Individual asymmetry in colouration changed considerably over a period of 3 months. This suggests that colouration is a dynamic feature during adulthood and that males are capable of tracking and strategically exploiting their lateral asymmetry in accordance with their social environment.     

Tackling the taxonomic impediment: a global assessment for ant‐nest beetle diversity (Coleoptera: Carabidae: Paussini)

We evaluated the completeness and historical trends of the taxonomic knowledge of the myrmecophilous ground beetle tribe Paussini (Coleoptera, Carabidae, Paussinae). Species accumulation curves were modelled using a logistic function. Similar analyses were conducted for genera and subgenera. Although not all biogeographical regions have been equally explored, accumulation curves reached a plateau in all cases. Our models predict that about 96% of the world fauna has been already described. However, the asymptotes calculated for the Australian and Oriental species should be interpreted as false plateaus because of the lack of recent research. Similarly, patterns of genera accumulation indicate that a plateau has been reached. As a result of continued debate on the use and validity of Paussini subgenera, the accumulation curves of subgenera showed stepped patterns, with no evidence of plateaus. Thus, although relatively few species are expected to be described in the future, the species accumulation curves indicate that the taxonomic inventory is not yet complete. Differences in accumulation patterns among biogeographical regions can be used to highlight the areas where more species are expected, and hence where taxonomical efforts should be concentrated. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 330–339.