Understory plant diversity is related to higher variability of vegetative mobility of coexisting species

Theoretical studies claim that if co-occurring species have very different mobilities this will result in greater small-scale species richness, but empirical evidence is still lacking. We measured horizontal vegetative mobility (VM) of 48 herbaceous understory species and estimated small-scale species richness in early and late successional boreonemoral herb-rich coniferous forests in central Estonia. VM of erosulate growth forms was significantly higher than that of hemi-rosette and rosette growth forms. Erosulate species exhibited higher mobility in young stands, but their relative and total cover was considerably higher in old stands. Local plant richness (in 1 × 1 m plots) correlated positively with the variability of VM of species in a plot—larger differences in VM resulted in a higher number of coexisting species. Our results thus suggest that species differences in VM can contribute to small-scale coexistence by providing different ways to colonise empty space. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Diagnostic pitfalls in the evaluation of fine needle aspiration cytology of the thyroid: correlation with histopathology in 260 cases

Objectives:  Fine needle aspiration cytology (FNAC) of the thyroid is a non-invasive, cost-effective screening procedure that is valuable for distinguishing neoplastic lesions from non-neoplastic nodules. The aim of this study was to determine the diagnostic accuracy of FNACs performed at our institution by correlating FNAC results with histopathological diagnoses.
Methods:  Two hundred and seventy-one aspiration cytology specimens followed by thyroidectomy were included in the study, and the results of 260 adequate FNACs were compared with their histological diagnoses.
Results:  The sensitivity and specificity of thyroid FNAC for detecting neoplasia were 92.6% and 91.6%, respectively. There were 15 (5.7%) false positives and six (2.3%) false negatives.
Conclusions:  The results showed that follicular cells that exhibit some of the features of papillary carcinoma could be observed in a cytology slide of Hashimoto's thyroiditis, leading to a diagnostic pitfall. In addition, cellularity and overlapping cytological criteria in hyperplasia might lead to a false diagnosis.     

Reproductive investment is connected to innate immunity in a long-lived animal

Life-history theory predicts that organisms optimize their resource allocation strategy to maximize lifetime reproductive success. Individuals can flexibly reallocate resources depending on their life-history stage, and environmental and physiological factors, which lead to variable life-history strategies even within species. Physiological trade-offs between immunity and reproduction are particularly relevant for long-lived species that need to balance current reproduction against future survival and reproduction, but their underlying mechanisms are poorly understood. A major unresolved issue is whether the first-line innate immune function is suppressed by reproductive investment. In this paper, we tested if reproductive investment is associated with the suppression of innate immunity, and how this potential trade-off is resolved depending on physiological state and residual reproductive value. We used long-lived capital-breeding female eiders (Somateria mollissima) as a model. We showed that the innate immune response, measured by plasma bacteria-killing capacity (BKC), was negatively associated with increasing reproductive investment, i.e., with increasing clutch size and advancing incubation stage. Females in a better physiological state, as indexed by low heterophil-to-lymphocyte (H/L) ratios, showed higher BKC during early incubation, but this capacity decreased as incubation progressed, whereas females in poorer state showed low BKC capacity throughout incubation. Although plasma BKC generally declined with increasing H/L ratios, this decrease was most pronounced in young females. Our results demonstrate that reproductive investment can suppress constitutive first-line immune defence in a long-lived bird, but the degree of immunosuppression depends on physiological state and age.     

Assessing the use of genomic DNA as a predictor of the maximum absorbance wavelength of avian SWS1 opsin visual pigments

Recently, in vitro mutation studies have made it possible to predict the wavelengths of maximum absorbance (λ_max) of avian UV/violet sensitive visual pigments (SWS1) from the identity of a few key amino acid residues in the opsin gene. Given that the absorbance spectrum of a cone’s visual pigment and of its pigmented oil droplet can be predicted from just the λ_max, it may become possible to predict the entire spectral sensitivity of a bird using genetic samples from live birds or museum specimens. However, whilst this concept is attractive, it must be validated to assess the reliability of the predictions of λ_max from opsin amino acid sequences. In this paper, we have obtained partial sequences covering three of the known spectral tuning sites in the SWS1 opsin and predicted λ_max of all bird species for which the spectral absorbance has been measured using microspectrophotometry. Our results validate the use of molecular data from genomic DNA to predict the gross differences in λ_max between the violet- and ultraviolet-sensitive subtypes of SWS1 opsin. Additionally, we demonstrate that a bird, the bobolink Dolichonyx oryzivorus L., can have more than one SWS1 visual pigment in its retina.     

Antioxidant and antimicrobial actions of the clubmoss <Emphasis Type="Italic">Lycopodium clavatum</Emphasis> L.

Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS) and identified lycopodine as the major alkaloid.     

Partial Opsin Sequences Suggest UV-Sensitive Vision is Widespread in Caudata

Ultraviolet (UV) vision exists in several animal groups. Intuitively, one would expect this trait to be favoured in species living in bright environments, where UV light is the most present. However, UV sensitivity, as deduced from sequences of UV photoreceptors and/or ocular media transmittance, is also present in nocturnal species, raising questions about the selective pressure maintaining this perceptual ability. Amphibians are among the most nocturnal vertebrates but their visual ecology remains poorly understood relative to other groups. Perhaps because many of these species breed in environments that filter out a large part of UV radiation, physiological and behavioural studies of UV sensitivity in this group are scarce. We investigated the extent of UV vision in Caudata, the order of amphibians with the most nocturnal habits. We could recover sequences of the UV sensitive SWS1 opsin in 40 out of 58 species, belonging to 6 families. In all of these species, the evidence suggests the presence of functional SWS1 opsins under purifying selection, potentially allowing UV vision. Interestingly, most species whose opsin genes failed to amplify exhibited particular ecological features that could drive the loss of UV vision. This likely wide distribution of functional UV photoreceptors in Caudata sheds a new light on the visual ecology of amphibians and questions the function of UV vision in nocturnal animal species.     

Seed macro and micro morphology of the selected <Emphasis Type="Italic">Nigella</Emphasis> (Ranunculaceae) taxa from Turkey and their systematic significance

Macro and micromorphological properties of intact and mature seeds of 12 taxa (species and varieties) belonging to Nigella L. (Ranunculaceae) was investigated using light and scanning electron microscopy. Material studied covers 11 species of 15 Turkish Nigella. Studied taxa were divided into two types. Type I has ovate to orbicular seeds that includes four species. Type II has triquedrous seeds and includes seven species. Type II was subdivided into two. Type IIa has triquedrous to subpyramidal seeds (five species) and Type IIb has triquedrous to subglobose seeds (two species). Further segregation was performed micromorphologically and an identification key of studied Nigella taxa was given. Studied Nigella taxa have a diverse macro and micromorphological characters that utilize to separate them from each other to assess the systematics of Nigella.     

Acaricidal effects of <Emphasis Type="Italic">Corymbia citriodora</Emphasis> oil containing <Emphasis Type="Italic">para</Emphasis>-menthane-3,8-diol against nymphs of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> (Acari: Ixodidae)

The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results obtained by methods A, C and E, the LC₅₀ range was 0.035–0.037 mg PMD/cm² and the LC₉₅ range was 0.095–0.097 mg PMD/cm² at 4 h of exposure; the LT₅₀ range was 2.1–2.8 h and the LT₉₅ range was 3.9–4.2 h at 0.1 mg PMD/cm². To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm²) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic to nymphs of I. ricinus and may be useful for tick control.     

Habitat-specific clutch size and cost of incubation in eiders reconsidered

The energetic incubation constraint hypothesis (EICH) for clutch size states that birds breeding in poor habitat may free up resources for future reproduction by laying a smaller clutch. The eider (Somateria mollissima) is considered a candidate for supporting this hypothesis. Clutch size is smaller in exposed nests, presumably because of faster heat loss and higher incubation cost, and, hence, smaller optimal clutch size. However, an alternative explanation is partial predation: the first egg(s) are left unattended and vulnerable to predation, which may disproportionately affect exposed nests, so clutch size may be underestimated. We experimentally investigated whether predation on first-laid eggs in eiders depends on nest cover. We then re-evaluated how nesting habitat affects clutch size and incubation costs based on long-term data, accounting for confounding effects between habitat and individual quality. We also experimentally assessed adult survival costs of nesting in sheltered nests. The risk of egg predation in experimental nests decreased with cover. Confounding between individual and habitat quality is unlikely, as clutch size was also smaller in open nests within individuals, and early and late breeders had similar nest cover characteristics. A trade-off between clutch and female safety may explain nest cover variation, as the risk of female capture by us, mimicking predation on adults, increased with nest cover. Nest habitat had no effect on female hatching weight or weight loss, while lower temperature during incubation had an unanticipated positive relationship with hatching weight. There were no indications of elevated costs of incubating larger clutches, while clutch size and colony size were positively correlated, a pattern not predicted by the ‘energetic incubation constraint’ hypothesis. Differential partial clutch predation thus offers the more parsimonious explanation for clutch size variation among habitats in eiders, highlighting the need for caution when analysing fecundity and associated life-history parameters when habitat-specific rates of clutch predation occur.