Facial Skin Coloration Affects Perceived Health of Human Faces

Numerous researchers have examined the effects of skin condition, including texture and color, on the perception of health, age, and attractiveness in human faces. They have focused on facial color distribution, homogeneity of pigmentation, or skin quality. We here investigate the role of overall skin color in determining perceptions of health from faces by allowing participants to manipulate the skin portions of color-calibrated Caucasian face photographs along CIELab color axes. To enhance healthy appearance, participants increased skin redness (a*), providing additional support for previous findings that skin blood color enhances the healthy appearance of faces. Participants also increased skin yellowness (b*) and lightness (L*), suggesting a role for high carotenoid and low melanin coloration in the healthy appearance of faces. The color preferences described here resemble the red and yellow color cues to health displayed by many species of nonhuman animals.     

Negative effects of agrocin 84-encoding Agrobacterium plasmids on symbiotic properties of Rhizobium meliloti

Two plasmids, pAgK84::Tn5-Mob from Agrobacterium radiobacter carrying genes for the production of agrocin 84, and RP4-4 from E. coli were inserted either separately or together into a strain of Rhizobium meliloti. Each of these plasmid-containing R. meliloti transconjugants was less effective than the wild type strain in their ability to fix nitrogen in Medicago tornata. The pAgK84::Tn5-Mob-containing transconjugant was significantly less effective than that containing RP4-4. The transconjugant strains were inferior to the wild type strain in their ability to nodulate seedlings and to compete for nodulation.     

Subcellular localization of the APOBEC3 proteins during mitosis and implications for genomic DNA deamination

Humans have seven APOBEC3 DNA cytosine deaminases. The activity of these enzymes allows them to restrict a variety of retroviruses and retrotransposons, but may also cause pro-mutagenic genomic uracil lesions. During interphase the APOBEC3 proteins have different subcellular localizations: cell-wide, cytoplasmic or nuclear. This implies that only a subset of APOBEC3s have contact with nuclear DNA. However, during mitosis, the nuclear envelope breaks down and cytoplasmic proteins may enter what was formerly a privileged zone. To address the hypothesis that all APOBEC3 proteins have access to genomic DNA, we analyzed the localization of the APOBEC3 proteins during mitosis. We show that APOBEC3A, APOBEC3C and APOBEC3H are excluded from condensed chromosomes, but become cell-wide during telophase. However, APOBEC3B, APOBEC3D, APOBEC3F and APOBEC3G are excluded from chromatin throughout mitosis. After mitosis, APOBEC3B becomes nuclear, and APOBEC3D, APOBEC3F and APOBEC3G become cytoplasmic. Both structural motifs as well as size may be factors in regulating chromatin exclusion. Deaminase activity was not dependent on cell cycle phase. We also analyzed APOBEC3-induced cell cycle perturbations as a measure of each enzyme’s capacity to inflict genomic DNA damage. AID, APOBEC3A and APOBEC3B altered the cell cycle profile, and, unexpectedly, APOBEC3D also caused changes. We conclude that several APOBEC3 family members have access to the nuclear compartment and can impede the cell cycle, most likely through DNA deamination and the ensuing DNA damage response. Such genomic damage may contribute to carcinogenesis, as demonstrated by AID in B cell cancers and, recently, APOBEC3B in breast cancers.     

Enhancing the egg's natural defence against bacterial penetration by increasing cuticle deposition

The cuticle is a proteinaceous layer covering the avian egg and is believed to form a defence to microorganism ingress. In birds that lay eggs in challenging environments, the cuticle is thicker, suggesting evolutionary pressure; however, in poultry, selection pressure for this trait has been removed because of artificial incubation. This study aimed to quantify cuticle deposition and to estimate its genetic parameters and its role on trans‐shell penetration of bacteria. Additionally, cuticle proteins were characterised to establish whether alleles for these genes explained variation in deposition. A novel and reliable quantification was achieved using the difference in reflectance of the egg at 650 nm before and after staining with a specific dye. The heritability of this novel measurement was moderate (0.27), and bacteria penetration was dependent on the natural variation in cuticle deposition. Eggs with the best cuticle were never penetrated by bacteria (P < 0.001). The cuticle proteome consisted of six major proteins. A significant association was found between alleles of one of these protein genes, ovocleidin‐116 (MEPE), and cuticle deposition (P = 0.015) and also between alleles of estrogen receptor 1 (ESR1) gene and cuticle deposition (P = 0.008). With the heritability observed, genetic selection should be possible to increase cuticle deposition in commercial poultry, so reducing trans‐generational transmission of microorganisms and reversing the lack of selection pressure for this trait during recent domestication.     

Molecular characterization of four Haemophilus influenzae serotype a strains isolated from patients in Quebec, Canada

Four epidemiologically unrelated Haemophilus influenzae serotype a (Hia) strains from patients in Quebec, Canada, were characterized and found to represent 3 distinct groups. One isolate, found to be biotype I and sequence type (ST)-62 by multilocus sequence typing, was shown to possess the copper- and zinc-containing superoxide dismutase gene, sodC, and was suspected to belong to clonal division II. The other 3 isolates were classified as clonal division I based on the absence of the sodC gene. Among the 3 sodC-negative Hia strains, 2 were biotype II and had related STs (ST-23 and ST-403) and highly similar DNA fingerprints, similar to a group of previously described Hia isolates causing invasive disease in Manitoba, Canada. The remaining sodC-negative strain belonged to biotype I and ST-4 and shared no common allele with ST-23, ST-403, or ST-62. This isolate also possessed the IS1016-bexA partial deletion, which is often associated with increased virulence. Despite the small number of isolates used in this study, our finding of 3 distinct groups shows the existence of a potential genetic diversity not previously described for Hia. Whether this genetic diversity is related to the severity and epidemiology of Hia disease requires further studies.     

Mutation of a conserved asparagine in the I-like domain promotes constitutively active integrins alphaLbeta2 and alphaIIbbeta3

The leukocyte beta2 integrins are heterodimeric adhesion receptors required for a functional immune system. Many leukocyte adhesion deficiency-1 (LAD-1) mutations disrupt the expression and function of beta2 integrins. Herein, we further characterized the LAD-1 mutation N329S in the beta2 inserted (I)-like domain. This mutation converted alphaLbeta2 from a resting into a high affinity conformer because alphaLbeta2N329S transfectants adhered avidly to ligand intercellular adhesion molecule (ICAM)-3 in the absence of additional activating agent. An extended open conformation is adopted by alphaLbeta2N329S because of its reactivity with the beta2 activation reporter monoclonal antibodies MEM148 and KIM127. A corresponding mutation in beta3 generated constitutively active alphaIIbbeta3 that adhered to fibrinogen. This Asn is conserved in all human beta subunits, and it resides before the last helix of the I-like domain, which is known to be important in activation signal propagation. By mutagenesis studies and review of existing integrin structures, we conjectured that this conserved Asn may have a primary role in shaping the I-like domain by stabilizing the conformation of the alpha7 helix and the beta6-alpha7 loop in the I-like domain.