Genetic structure of native ant supercolonies varies in space and time

Ant supercolonies are the largest cooperative units known in nature. They consist of networks of interconnected nests with hundreds of reproductive queens, where individuals move freely between nests, cooperate across nest boundaries and show little aggression towards non‐nestmates. The combination of high queen numbers and free mixing of workers, queens and brood between nests results in extremely low nestmate relatedness. In such low‐relatedness societies, cooperative worker behaviour appears maladaptive because it may aid random individuals instead of relatives. Here, we provide a comprehensive picture of genetic substructure in supercolonies of the native wood ant Formica aquilonia using traditional population genetic as well as network analysis methods. Specifically, we test for spatial and temporal variation in genetic structure of different classes of individuals within supercolonies and analyse the role of worker movement in determining supercolony genetic networks. We find that relatedness within supercolonies is low but positive when viewed on a population level, which may be due to limited dispersal of individuals and/or ecological factors such as nest site limitation and competition against conspecifics. Genetic structure of supercolonies varied with both sample class and sampling time point, which indicates that mobility of individuals varies according to both caste and season and suggests that generalizing has to be carried out with caution in studies of supercolonial species. Overall, our analysis provides novel evidence that native wood ant supercolonies exhibit fine‐scale genetic substructure, which may explain the maintenance of cooperation in these low‐relatedness societies.     

Response of the lichen-eating moth <Emphasis Type="Italic">Cleorodes lichenaria</Emphasis> larvae to varying amounts of usnic acid in the lichens

Lichens are characterized by a great variety of secondary metabolites. The function of these substances remains partly unknown. In this study, we propose that some of these metabolites may expel insect herbivores. To test this hypothesis, we reared larvae of the lichenivorous moth Cleorodes lichenaria on three selected lichens, Cladonia arbuscula subsp. mitis, Usnea hirta, and Usnea dasypoga. In experimental setup, the secondary metabolite usnic acid was removed from the lichens with acetone prior to feeding, whereas a control was left untreated. On all three lichens, removal of usnic acid from the lichens using acetone significantly prolonged survival of larvae and increased their viability. Larvae reared on control lichens contained significantly more usnic acid than those reared on treated lichens, both in their biomass and their faeces. These results support the hypothesis that usnic acid serves as a repellent against insect feeding, besides its well established functions of UV protection and antimicrobial properties.     

Association of Angiopoietin-2 and Ki-67 Expression with Vascular Density and Sunitinib Response in Metastatic Renal Cell Carcinoma

The Angiopoietin-2 (Ang2, Angpt2) growth factor is a context-dependent antagonist/agonist ligand of the endothelial Tie2 receptor tyrosine kinase and known to promote tumour angiogenesis and metastasis. Angiopoietin antagonists have been tested in clinical cancer trials in combination with VEGF-based anti-angiogenic therapy, including sunitinib, which is widely used as a first-line therapy for metastatic renal cell carcinoma (mRCC). However, little is known about Ang2 protein expression in human tumours and the correlation of tumour Ang2 expression with tumour vascularization, tumour cell proliferation and response to anti-angiogenic therapies. Here, we evaluated, using immunohistochemistry, the expression of Ang2, CD31 and the cell proliferation marker Ki-67 in the primary kidney cancer from 136 mRCC patients, who received first-line sunitinib after nephrectomy. Ang2 protein expression was restrained to RCC tumour vessels, and correlated with tumour vascularization and response to sunitinib. High pre-therapeutic Ang2 expression, and more strongly, combined high expression of both Ang2 and CD31, were associated with a high clinical benefit rate (CBR). Low cancer Ki-67 expression, but not Ang2 or CD31 expression, was associated with favourable progression-free (PFS) and overall survival (OS) as compared to patients with high Ki-67 expression (PFS 6.5 vs. 10.6 months, P = 0.009; OS, 15.7 vs. 28.5 months, P = 0.015). In summary, in this study to investigate endothelial Ang2 in mRCC patients treated with first-line sunitinib, high cancer Ang2 expression was associated with the CBR, but not PFS or OS, whereas low Ki-67 expression was significantly associated with long PFS and OS.     

Life Satisfaction and Morbidity among Postmenopausal Women

Objective

To investigate associations between morbidity and global life satisfaction in postmenopausal women taking into account type and number of diseases.

Materials and Methods

A total of 11,084 women (age range 57–66 years) from a population-based cohort of Finnish women (OSTPRE Study) responded to a postal enquiry in 1999. Life satisfaction was measured with a 4-item scale. Self-reported diseases diagnosed by a physician and categorized according to ICD-10 main classes were used as a measure of morbidity. Enquiry data on health and lifestyle were used as covariates in the multivariate logistic models.

Results

Morbidity was strongly associated with life dissatisfaction. Every additional disease increased the risk of life dissatisfaction by 21.1% (p < .001). The risk of dissatisfaction was strongest among women with mental disorders (OR = 5.26; 95%CI 3.84–7.20) and neurological disorders (OR = 3.62; 95%CI 2.60–5.02) compared to the healthy (each p < .001). Smoking, physical inactivity and marital status were also associated with life dissatisfaction (each p < .001) but their introduction to the multivariate model did not attenuate the pattern of associations.

Conclusions

Morbidity and life dissatisfaction have a disease-specific and dose-dependent relationship. Even if women with mental and neurological disorders have the highest risk for life dissatisfaction, monitoring life satisfaction among aging women regardless of disorders should be undertaken in order to intervene the joint adverse effects of poor health and poor well-being.     

Dormancy release in Pinus sylvestris L. and Picea abies (L.) Karst. seedlings: effects of intermittent warm periods during chilling

Summary Experiments designed to test three simulation models were used to study the effects of intermittent warm periods during the chilling period on dormancy release in 2-year-old seedlings of Pinus sylvestris L. and Picea abies (L.) Karst. The effect of the intermittent period varied according to its timing. Compared with corresponding continuous chilling treatments, the intermittent periods (1) after 1–3 weeks of chilling increased the proportion of the seedlings for which dormancy was subsequently released, and (2) after 4–7 weeks of chilling substantially diminished this proportion. The intermittent periods did not affect the time required for growth initiation in forcing conditions. These results support a simulation model with a strict end-point for the rest period. On the basis of the experimental results, division of the dormant period into three sub-periods is proposed.     

The ability of isolated myocardial cells of the rat to contract at temperatures near freezing point

1. 1.|Single spontaneously-beating myocardial cells were prepared by enzymatic isolation from rat heart ventricles. Using a TV camera and videotape recorder, beating parameters were characterized with respect to temperature.

2. 2.|The cells obtained showed two types of contractions: (a) action-potential-coupled, fast contractions, which could be triggered electrically but sometimes also occurred spontaneously; and (b) a phasic type of contraction which occurs spontaneously as a slowly (25–200 μm s⁻¹) proceedings wave through the cell and is not coupled to the action potential.

3. 3.|Both the spontaneous phasic and electrically-triggered fast contractions continued down to about 0°C, where the cells went into an irreversible contracture, but recovered if the temperature was raised before the contracture occurred.

4. 4.|In physically-contracting cells, the beat rate and the velocity of the contraction wave were temperature dependent showing a linear relationship on an Arrhenius plot; apparent activation energies were 31 and 54 kJ mol⁻¹, respectively.

5. 5.|When fast contractions were triggered by electric field stimulation, the threshold of cells was reduced as temperature rose. The rheobase values showed that cell excitability decreased more steeply when the temperature fell below 20°C. This change could not be seen in the values of chronaxie, which showed a linear relationship on the Arrhenius plot within the whole temperature range used (6–35°C).

6. 6.|It is concluded that the lower temperature limit is not the same for all structural levels of the rat heart. Myocardial cells are able to contract still at the freezing point while mechanisms initiating the heart beat require higher temperatures to be functional.

Paleolimnological reflections of fiber-plant retting in the sediment of a small clear-water lake

Likolampi is a small groundwater kettle-hole lake in Ilomantsi, Eastern Finland. At 11 m water depth the uppermost 51 cm of sediment contains about 390 varves. A thin layer of chrysophyte statospores is the main structural unit in these; in some varves it is followed by a layer of cf. Drepanocladus fluitans moss spores. Below the laminated sequence, two layers of moss detritus (110–87 cm, 81–51 cm) alternate with greyish brown fine detritus. Pollen analysis reveals that the start of the deposition of varved sediment coincides with the beginning of intensive fiber plant retting with large quantities of Cannabis/Humulus -type pollen and even regular occurrence of the insect-pollinated Linum usitatissimum. The cf. Drepanocladus spores are almost absent during the retting period (c. 1590–1900 by the varves), but very common before and after it. Drepanocladus fluitans is capable of assimilating dissolved CO₂ in water, so it thrives at low pH and is typical for oligotrophic clear-water lakes. We conclude that the stratigraphy of Drepanocladus fragments and spores is a true negative indicator of cultural influence in Likolampi.     

Prostacyclin,thromboxane and prostaglandin F2αin suction blister fluid of human skin: Effect of systemic aspirin and local glucocorticosteroid treatment

Changes in prostaglandin (PG) metabolism are known to be involved in various skin diseases. To elucidate the behavior of hree vasoactive PGs in human skin, namely prostacyclin (PG1₂), thromboxane A₂ (TxA₂) and PGF_2α, their stable metabolites, 6-keto-PGF_1α. TxB₂, and 13, 14 dihydro-15-keto PGF_2α (MPGF_2α), respectively, were measured by radioimmunoassays in suction blister fluids of 29 healthy male subjects. Nine of them were treated with acetylsalicylic acid (0.5 g × 4/day for one day beforehand), eight with local glucocorticoid (clobetasol-17-propionate, Dermovat^R Cream, twice a day for seven days) and 12 served as controls. All three PGs were detected in blister fluid. In controls the mean (±SD) concentration of 6-keto-PGF_1α was 1160 ± 470 pg/ml (n=12) that of TxB₂ 1590 ± 610 pg/ml (n=12) and that of MPGF_2α 1800 ± 710 pg/ml (n=12), levels which are higher than the respective concentrations in human plasma. The preceding aspirin treatment decreased the 6-keto-PGF_1α levels by 40 % (P<0.005), the TxB₂ levels by 80 % (P<0.001) and MPGF_2α levels by 35 % (P<0.05), whereas the preceding local glucocorticoid caused no changes in these PG levels. The results show that 1) PG1₂, TxA₂, and PGF_2α are locally released in the suction blister fluid of healthy human skin, 2) systemic treatment with a PG synthesis inhibiting drug, acetysalicylic acid, reduces this release, and 3) locally applied clobetasol-17-propionate does not affect the levels of prostaglandins and thromboxane as measured by our methods.     

Electron microscopy of the paracervical (Frankenhäuser) ganglion of the adult rat

Summary The ultrastructure of the paracervical (Frankenhäuser) ganglion in the rat was studied after immersion or perfusion fixation with glutaraldehyde followed by post-osmification. This ganglion is located at the uterovaginal junction in the vicinity of arteria uterina and contains three neuronal cell types. (1) Principal neurons have a fine structure mainly similar to the ganglion cells of other autonomic ganglia. (2) Small granule-containing cells occur in clusters often close to fenestrated capillaries. They are divided into two subgroups according to the size of their cytoplasmic granules; those containing only small granulated vesicles of 800 to 1400 Å in diameter and those having also large granulated vesicles of 2000 to 3000 Å in diameter. (3) Vacuolated nerve cells are large cells that resemble the principal neurons in their cytoplasmic components, except that they contain one to ten vacuoles with corpuscles of different size and shape. The possible physiological significance of the small, granule-containing cells in the uterine function is discussed.