Phenotypic and Evolutionary Consequences of Social Behaviours: Interactions among Individuals Affect Direct Genetic Effects

Traditional quantitative genetics assumes that an individual''s phenotype is determined by both genetic and environmental factors. For many animals, part of the environment is social and provided by parents and other interacting partners. When expression of genes in social partners affects trait expression in a focal individual, indirect genetic effects occur. In this study, we explore the effects of indirect genetic effects on the magnitude and range of phenotypic values in a focal individual in a multi-member model analyzing three possible classes of interactions between individuals. We show that social interactions may not only cause indirect genetic effects but can also modify direct genetic effects. Furthermore, we demonstrate that both direct and indirect genetic effects substantially alter the range of phenotypic values, particularly when a focal trait can influence its own expression via interactions with traits in other individuals. We derive a function predicting the relative importance of direct versus indirect genetic effects. Our model reveals that both direct and indirect genetic effects can depend to a large extent on both group size and interaction strength, altering group mean phenotype and variance. This may lead to scenarios where between group variation is much higher than within group variation despite similar underlying genetic properties, potentially affecting the level of selection. Our analysis highlights key properties of indirect genetic effects with important consequences for trait evolution, the level of selection and potentially speciation.     

The Prognostic Value of Tumor-Infiltrating lymphocytes in Stage II Colon Cancer. A Nationwide Population-Based Study

BACKGROUND: Additional prognostic markers are needed for better treatment stratification of stage II colon cancer (CC). We investigated the prognostic value of tumor-infiltrating lymphocytes (TILs) in a true population-based cohort of patients with stage II CC. MATERIAL AND METHODS: A total of 573 patients were included. Tumor blocks representing the deepest invasive part of the primary tumor were used for analysis. CD3+ and CD8+ TILs at the invasive front were evaluated by immunohistochemistry on whole tumor sections. The invasive area was manually outlined, and Visiopharm Integrator System software was used for quantification. Data were dichotomized for comparison with clinical data. The prognostic value was investigated in Cox proportional-hazard models for recurrence-free survival (RFS) and overall survival (OS). RESULTS: Low CD3+ or CD8+ TILs were significantly associated with poor RFS and OS (P?=?.0021 and P?≤?.0009, respectively, log-rank test). In multiple Cox regression analysis, low CD3+ and CD8+ TILs were associated with reduced RFS with hazard ratio (HR)?=?1.386 (95% CI 1.039-1.850), P?=?.026, and HR?=?1.394 (95% CI 1.029-1.890), P?=?.032, respectively, independent of age, T-stage, localization, perforation, and microsatellite instability (MSI). In the subgroups of patients with low CD3+ or CD8+ TILs, there was no difference in survival between patients with MSI and microsatellite-stable tumors, (P?=?.821 and P?=?.907, respectively). CONCLUSION: Low CD3+ and CD8+ TILs in the invasive area are both related to inferior prognosis of stage II CC, and we recommend either of these parameters to be considered as additional high-risk factor.     

Cleavage of chitinous elicitors from the ectomycorrhizal fungus Hebeloma crustuliniforme by host chitinases prevents induction of K+ and Cl− release, extracellular alkalinization and H2O2 synthesis of Picea abies cells

Rapid reactions comprising efflux of K⁺ and Cl⁻, phosphorylation of a 63-kDa protein (pp63), extracellular alkalinization and synthesis of H₂O₂ are equally induced in cells of Picea abies (L.) Karst. by chitotetraose, colloidal chitin and cell wall elicitors from the ectomycorrhizal fungus Hebeloma crustuliniforme (Bull. ex Fries.) Quél. an ectomycorrhizal partner of spruce. Cleavage of fungal cell wall elicitors and of artificial chitin elicitors to monomeric and dimeric fragments by apoplasmic spruce chitinases (36-kDa class I chitinase, pI 8.0, and 28-kDa chitinase, pI 8.7; EC 3.2.1.14) equally prevented induction of these rapid reactions. Also, N-acetylglucosamine oligomers and elicitors from the fungal cell walls showed a similar dependence of their activity on the degree of polymerisation. From these results it is suggested that, during ectomycorrhiza formation, only some of the chitin-derived elicitors reach their receptors at the plant plasma membrane, initiating reactions of the hypersensitive response in the host cells. The remaining fungal elicitors will be degraded to varying extents by wall-localized chitinases of the host root, reducing the defence reactions of the plant and allowing symbiotic interactions of both organisms. Received: 6 January 1997 / Accepted: 14 March 1997     

Die Isolierung und quantitative Bestimmung der Carotinoide und Chlorophylle von Blättern,Algen und isolierten Chloroplasten mit Hilfe dünnschichtchromatographischer Methoden

Zusammenfassung Es werden dünnschichtchromatographische Methoden zur schnellen quantitativen Bestimmung der Chlorophylle und Carotinoide angegeben. Als Beispiel für verschiedenes pflanzliches Ausgangsmaterial wird die Extraktion der Farbstoffe aus Algen, Blättern oder Chloroplasten genauer beschrieben.Aus diesen Extrakten erfolgt die Auftrennung der Carotinoide nach einem adsorptionschromatographischen Verfahren; die Dünnschicht ist hierbei aus anorganischen Adsorbentien (CaCO₃, MgO, Ca(OH)₂) zusammengesetzt. Die Basizität der Schicht wird durch Zugabe von KOH weiter verstärkt; dadurch gelingt es, die Chlorophylle am Auftragungsort zurückzuhalten, so daß die sonst auftretenden störenden Überlagerungen von Chlorophyllen und Xanthophyllen im Chromatogramm einwandfrei vermieden werden können. Mit dieser Methode lassen sich auch, solche Carotinoide separieren, welche sich nur in der Lage einer Doppelbindung unterscheiden, wie z. B. - und -Carotin oder Lutein und Zeaxanthin. In einem einzigen Chromatogramm ist deshalb die Trennung aller wesentlichen Carotinoide möglich, aus einem Chlorella-Extrakt z. B. (mit fallendem R_f-Wert): -Carotin, Lutein-5,6-Epoxyd (Spuren), Violaxanthin, Lutein, Antheraxanthin, Neoxanthin Neo A, Neoxanthin und Zeaxanthin. Ferner wird das chromatographische Verhalten der nicht allgemein vorkommenden Carotinoide -Carotin, -Carotin, Lycopin und Rhodoxanthin beschrieben.Die Chlorophylle a und b werden aus dem Gesamtextrakt auf einer zweiten Dünnschicht nach einem verteilungschromatographischen Verfahren getrennt; diese Schicht besteht aus Kieselgel, dem Ascorbinsäure als Oxidationsschutz beigemischt wird. Eine Apparatur zur gleichmäßigen, strichförmigen Auftragung definierter Extraktmengen und Vorrichtungen zur schnellen quantitativen Eluierung der Farbstoffe aus dem Adsorbens werden beschrieben.Die für die Berechnung der Farbstoffmengen noch fehlenden spezifischen Extinktionskoeffizienten E _{1 cm} ^{1 %} für Antheraxanthin in Äthanol und -Carotin in Chloroform wurden ermittelt.

---

Extraction and quantitative determination of carotenoids and chlorophylls of leaves, algae and isolated chloroplasts with the aid of thin-layer chromatography

Summary Methods for a rapid quantitative determination of chlorophylls and carotenoids are decribed.The extraction of pigments was carried out with different kinds of plant material, such as algae, leaves and chloroplasts. The separation of the carotenoids from these extracts was succeeded by an adsorptionchromatographic process in which the thin-layer consists of anorganic adsorbents (CaCO₃, MgO, Ca(OH)₂). The basicity of the layer is further increased by the addition of KOH; thereby the chlorophylls are retained at the starting line and the overlapping of chlorophylls and xanthophylls on the chromatogram can be avoided.With this method even those carotenoids can be separated which differ only in the position of a double bond, as for instance - and -carotene, and lutein and zeaxanthin. Thus the separation of all the principal carotenoids on a single chromatogram is possible, for example from a Chlorella extract (in order of decreasing R_f-value): -carotene, -carotene, lutein-5,6-epoxide (traces), violaxathin, lutein, antheraxanthin, neoxanthin neo A, neoxanthin and zeaxanthin. Furthermore the chromatographic behaviour of the carotenoids -carotene, -carotene, lycopene and rhodoxanthin, which are found only rarely, is described.The chlorophylls a and b are separated by a partition chromatographic process on the second thin-layer; this layer consists of silica gel mixed with ascorbic acid as an antioxidant. An apparatus for an equal spreading of defined quantities of the extract on the starting line and new methods for a rapid quantitative elution of the pigments from the adsorbent are described.The specific extinction coefficients E _{1 cm} ^{1 %} for antheraxanthin in ethanol and for -carotene in chloroform, which were needed for the calculation of the pigment quantity were determined.

     

Vibrational signals of African stingless bees

Insectes Sociaux - Many bee species produce thoracic vibrations in various contexts. Among the social stingless bees (Meliponini) pulsed thoracic vibrations are used to communicate with nestmates....     

Hepatocyte transplantation (HTx) corrects selected neurometabolic abnormalities in murine intermediate maple syrup urine disease (iMSUD)

Skvorak et al. [1] demonstrated the therapeutic efficacy of HTx in a murine model of iMSUD, confirming significant metabolic improvement and survival. To determine the effect of HTx on extrahepatic organs, we examined the metabolic effects of HTx in brain from iMSUD animals. Amino acid analysis revealed that HTx corrected increased ornithine, partially corrected depleted glutamine, and revealed a trend toward alloisoleucine correction. For amino acid and monoamine neurotransmitters, decreased GABA was partially corrected with HTx, while the l-histidine dipeptide of GABA, homocarnosine, was decreased in iMSUD mice and hypercorrected following HTx. Elevated branched-chain amino acids (BCAA; leucine, isoleucine, and valine) in MSUD can deplete brain tyrosine and tryptophan (the precursors of monoamine neurotransmitters, dopamine (DA) and serotonin (5-hydroxytryptamine; 5-HT)) through competition via the large neutral amino acid transporter. HTx corrected decreased DA levels and the DA metabolite, 3-methoxytyramine, and partially corrected the DA intermediate 3,4-dihydroxyphenylacetate (DOPAC) and 5-HT levels, despite normal tyrosine and tryptophan levels in iMSUD mouse brain. We further observed enhanced intracellular turnover of both DA and 5-HT in iMSUD mouse brain, both of which partially corrected with HTx. Our results suggest new pathomechanisms of neurotransmitter metabolism in this disorder and support the therapeutic relevance of HTx in iMSUD mice, while providing proof-of-principle that HTx has corrective potential in extrahepatic organs.