Vegetarianism,female gender and increasing age,but not <Emphasis Type="Italic">CNDP1</Emphasis> genotype,are associated with reduced muscle carnosine levels in humans

Carnosine is found in high concentrations in skeletal muscles, where it is involved in several physiological functions. The muscle carnosine content measured within a population can vary by a factor 4. The aim of this study was to further characterize suggested determinants of the muscle carnosine content (diet, gender and age) and to identify new determinants (plasma carnosinase activity and testosterone). We investigated a group of 149 healthy subjects, which consisted of 94 men (12 vegetarians) and 55 women. Muscle carnosine was quantified in M. soleus, gastrocnemius and tibialis anterior using magnetic resonance proton spectroscopy and blood samples were collected to determine CNDP1 genotype, plasma carnosinase activity and testosterone concentrations. Compared to women, men have 36, 28 and 82% higher carnosine concentrations in M. soleus, gastrocnemius and tibialis anterior muscle, respectively, whereas circulating testosterone concentrations were unrelated to muscle carnosine levels in healthy men. The carnosine content of the M. soleus is negatively related to the subjects’ age. Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores. In contrast, there is no difference in muscle carnosine content between omnivores with a high or low ingestion of β-alanine. Muscle carnosine levels are not related to the polymorphism of the CNDP1 gene or to the enzymatic activity of the plasma carnosinase. In conclusion, neither CNDP1 genotype nor the normal variation in circulating testosterone levels affects the muscular carnosine content, whereas vegetarianism, female gender and increasing age are the factors associated with reduced muscle carnosine stores.     

Surface adhesion of fusion proteins containing the hydrophobins HFBI and HFBII from Trichoderma reesei

Hydrophobins are surface-active proteins produced by filamentous fungi, where they seem to be ubiquitous. They have a variety of roles in fungal physiology related to surface phenomena, such as adhesion, formation of surface layers, and lowering of surface tension. Hydrophobins can be divided into two classes based on the hydropathy profile of their primary sequence. We have studied the adhesion behavior of two Trichoderma reesei class II hydrophobins, HFBI and HFBII, as isolated proteins and as fusion proteins. Both hydrophobins were produced as C-terminal fusions to the core of the hydrolytic enzyme endoglucanase I from the same organism. It was shown that as a fusion partner, HFBI causes the fusion protein to efficiently immobilize to hydrophobic surfaces, such as silanized glass and Teflon. The properties of the surface-bound protein were analyzed by the enzymatic activity of the endoglucanase domain, by surface plasmon resonance (Biacore), and by a quartz crystal microbalance. We found that the HFBI fusion forms a tightly bound, rigid surface layer on a hydrophobic support. The HFBI domain also causes the fusion protein to polymerize in solution, possibly to a decamer. Although isolated HFBII binds efficiently to surfaces, it does not cause immobilization as a fusion partner, nor does it cause polymerization of the fusion protein in solution. The findings give new information on how hydrophobins function and how they can be used to immobilize fusion proteins.     

Fe(II) Oxidation Is an Innate Capability of Nitrate-Reducing Bacteria That Involves Abiotic and Biotic Reactions

Phylogenetically diverse species of bacteria can catalyze the oxidation of ferrous iron [Fe(II)] coupled to nitrate (NO₃⁻) reduction, often referred to as nitrate-dependent iron oxidation (NDFO). Very little is known about the biochemistry of NDFO, and though growth benefits have been observed, mineral encrustations and nitrite accumulation likely limit growth. Acidovorax ebreus, like other species in the Acidovorax genus, is proficient at catalyzing NDFO. Our results suggest that the induction of specific Fe(II) oxidoreductase proteins is not required for NDFO. No upregulated periplasmic or outer membrane redox-active proteins, like those involved in Fe(II) oxidation by acidophilic iron oxidizers or anaerobic photoferrotrophs, were observed in proteomic experiments. We demonstrate that while “abiotic” extracellular reactions between Fe(II) and biogenic NO₂⁻/NO can be involved in NDFO, intracellular reactions between Fe(II) and periplasmic components are essential to initiate extensive NDFO. We present evidence that an organic cosubstrate inhibits NDFO, likely by keeping periplasmic enzymes in their reduced state, stimulating metal efflux pumping, or both, and that growth during NDFO relies on the capacity of a nitrate-reducing bacterium to overcome the toxicity of Fe(II) and reactive nitrogen species. On the basis of our data and evidence in the literature, we postulate that all respiratory nitrate-reducing bacteria are innately capable of catalyzing NDFO. Our findings have implications for a mechanistic understanding of NDFO, the biogeochemical controls on anaerobic Fe(II) oxidation, and the production of NO₂⁻, NO, and N₂O in the environment.     

Porcine arterivirus attachment to the macrophage-specific receptor sialoadhesin is dependent on the sialic acid-binding activity of the N-terminal immunoglobulin domain of sialoadhesin

The sialic acid-binding lectin sialoadhesin (Sn) is a macrophage-restricted receptor for porcine reproductive and respiratory syndrome virus (PRRSV). To investigate the importance of pSn sialic acid-binding activity for PRRSV infection, an R₁₁₆-to-E mutation was introduced in the predicted sialic acid-binding domain of pSn, resulting in a mutant, pSn^RE, that could not bind sialic acids. PSn, but not pSn^RE, allowed PRRSV binding and internalization. These data show that the sialic acid-binding activity of pSn is essential for PRRSV attachment to pSn and thus identifies the variable, N-terminal domain of Sn as a PRRSV binding domain.     

Sunless skin tanning with dihydroxyacetone delays broad-spectrum ultraviolet photocarcinogenesis in hairless mice

Sunless tanning with dihydroxyacetone (DHA) is not considered to be a sunscreen although it does absorb parts of the ultraviolet (UV) spectrum. We investigated the protection with topical application of DHA against solar UV-induced skin carcinogenesis in lightly pigmented hairless hr/hr C3H/Tif mice. Broad-spectrum UV radiation, simulating the UV part of the solar spectrum was obtained from one Philips TL12 and five Bellarium-S SA-1-12 tubes. Three groups of mice were UV-exposed four times a week to a dose-equivalent of four times the standard erythema dose (SED), without or with application of 5 or 20% DHA only twice a week. Similarly, three groups of mice were treated with DHA and irradiated with a high UV dose (8 SED), simulating a skin burn. Two groups (controls) were not irradiated, but either left untreated or treated with 20% DHA alone. The UV-induced skin pigmentation by melanogenesis could easily be distinguished from DHA-induced browning and was measured by a non-invasive, semi-quantitative method. Application of 20% DHA reduced by 63% the pigmentation produced by 4 SED, however, only by 28% the pigmentation produced by 8 SED. Furthermore, topical application of 20% DHA significantly delayed the time to appearance of the first tumor ≥1 mm (P=0.0012) and the time to appearance of the third tumor (P=2×10⁻⁶) in mice irradiated with 4 SED. However, 20% DHA did not delay tumor development in mice irradiated with 8 SED. Application of 5% DHA did not influence pigmentation or photocarcinogenesis.In conclusion, this is the first study to show that the superficial skin coloring generated by frequent topical application of DHA in high concentrations may delay skin cancer development in hairless mice irradiated with moderate UV doses.     

High-resolution histographical mapping of glucose concentrations in developing cotyledons of Vicia faba in relation to mitotic activity and storage processes: glucose as a possible developmental trigger

Previous studies provided evidence that the carbohydrate status triggers developmental processes in the growing cotyledons of Vicia faba . We describe here the high-resolution mapping of glucose concentrations in tissue sections of developing faba bean cotyledons by quantitative bioluminescence and single-photon imaging. Patterns of local glucose distributions are compared with tissue cell type, mitotic index and the distribution pattern of starch. During cotyledon differentiation, gradients in the glucose concentration emerge which are related to the particular cell type. Higher concentrations are found in non-differentiated premature regions of the cotyledon whereas mature starch-accumulating regions contain particularly low concentrations of glucose. In addition, glucose concentration is correlated to mitotic activity. The glucose distribution pattern is therefore related to the developmental gradient. Our data provide for the first time evidence for steep glucose gradients across developing plant embryos and favour the idea that sugar gradients may have morphogenic functions in developing cotyledons.     

Die Hypokotylfarbe als Markierungsfaktor von Genomstufen der Zuckerrübe

Zusammenfassung In zunehmendem Maße werden anisoploideBeta-Rübensorten angebaut, deren zytologische Kontrolle zwecks Feststellung der Genomstufenprozentanteile recht arbeitszeitaufwendig ist. Übereinstimmend mit polnischen Autoren wurde festgestellt, daß die Hypokotylfarbe ein geeigneter Markierungsfaktor für die einzelnen Genomstufen darstellt. Kreuzt man tetraploide Pflanzen, die ein grünes Hypokotyl besitzen, mit diploiden Pflanzen, die ein rosa Hypokotyl aufweisen, so erhält man von dem tetraploiden Partner tetraploide grüne und triploide hellbraune, von dem diploiden Partner diploide rosa und triploide hellbraune Nachkommenschaften. Die in bezug auf die Hypokotylfarbe heterozygoten Pflanzen kann man demnach von den homozygot grünen und homozygot rosa Individuen unterscheiden. Die Kreuzung diploid grünxtetraploid rosa ist für diese Zwecke nicht brauchbar, da sich die triploiden Heterozygoten mit einem grünen und zwei rosa Allelen in der Hypokotylfarbe nicht deutlich von den homozygoten rosa Pflanzen abheben. Auf die Bedeutung dieser Markierungsmöglichkeit für bestimmte Forschungsprobleme, die Züchtung und die Saatgutkontrolle wird hingewiesen.