Patterns of Early Gut Colonization Shape Future Immune Responses of the Host

The most important trigger for immune system development is the exposure to microbial components immediately after birth. Moreover, targeted manipulation of the microbiota can be used to change host susceptibility to immune-mediated diseases. Our aim was to analyze how differences in early gut colonization patterns change the composition of the resident microbiota and future immune system reactivity. Germ-free (GF) mice were either inoculated by single oral gavage of caecal content or let colonized by co-housing with specific pathogen-free (SPF) mice at different time points in the postnatal period. The microbiota composition was analyzed by denaturing gradient gel electrophoresis for 16S rRNA gene followed by principal component analysis. Furthermore, immune functions and cytokine concentrations were analyzed using flow cytometry, ELISA or multiplex bead assay. We found that a single oral inoculation of GF mice at three weeks of age permanently changed the gut microbiota composition, which was not possible to achieve at one week of age. Interestingly, the ex-GF mice inoculated at three weeks of age were also the only mice with an increased pro-inflammatory immune response. In contrast, the composition of the gut microbiota of ex-GF mice that were co-housed with SPF mice at different time points was similar to the gut microbiota in the barrier maintained SPF mice. The existence of a short GF postnatal period permanently changed levels of systemic regulatory T cells, NK and NKT cells, and cytokine production. In conclusion, a time window exists that enables the artificial colonization of GF mice by a single oral dose of caecal content, which may modify the future immune phenotype of the host. Moreover, delayed microbial colonization of the gut causes permanent changes in the immune system

Interactions of DNA with a new Platinum(IV) Azide Dipyridine complex activated by UVA and visible light : relationship to toxicity in tumor cells

The Pt IV diazido complex trans,trans,trans-[Pt(N 3) 2(OH) 2(pyridine) 2] (1) is unreactive in the dark but is cytotoxic when photoactivated by UVA and visible light. We have shown that 1 when photoactivated accumulates in tumor cells and binds strongly to nuclear DNA under conditions in which it is toxic to tumor cells. The nature of the DNA adducts, including conformational alterations, induced by photoactivated 1 are distinctly different from those produced in DNA by conventional cisplatin or transplatin. In addition, the observation that major DNA adducts of photoactivated 1 are able to efficiently stall RNA polymerase II more efficiently than cisplatin suggests that transcription inhibition may contribute to the cytotoxicity levels observed for photoactivated 1. Hence, DNA adducts of 1 could trigger a number of downstream cellular effects different from those triggered in cancer cells by DNA adducts of cisplatin. This might lead to the therapeutic effects that could radically improve chemotherapy by platinum complexes. The findings of the present work help to explain the different cytotoxic effects of photoactivated 1 and conventional cisplatin and thereby provide new insights into mechanisms associated with the antitumor effects of platinum complexes photoactivated by UVA and visible light. © 2012 American Chemical Society

NMR of 57Fe, 69Ga and 71Ga in Ga substituted magnetite

We report the NMR spectra of gallium substituted magnetite measured at temps. 4.2, 77 and 273 K. A single crystal of Fe3-xGaxO4, x = 0.05 has been prepd. by a floating zone technique. The Ga-lines found in the NMR spectrum above Verwey temp. Tv .apprx. 117 K indicate a preference of Ga substitution into the tetrahedral A-sites. The well-resolved structure of Ga-lines has been identified and assigned to both Ga isotopes below TV. A weak quadrupolar interaction contributes only to the line broadening. [on SciFinder (R)

57Fe NMR study of manganese ferrites

Magnetic properties of the manganese ferrites Mnx Fe3 - x O4 are markedly influenced by the valence states of Mn and Fe ions and by their distribution between the octahedral and tetrahedral sublattices. Hyperfine methods are capable of providing useful information on these characteristics, which is difficult to obtain otherwise. In the present contribution the Mnx Fe3 - x O4 (0.52 <x <1.80) cubic single crystals are studied by means of 57Fe nuclear magnetic resonance (NMR) at the liquid helium temperature. High quality samples and sensitive NMR equipment allowed to detect several well resolved 57Fe NMR spectral lines in the frequency range of 67-74 MHz in zero external magnetic field. In order to find out the location of iron nuclei from which the lines originate we applied external magnetic fields up to 1 T. This approach allows assignment of two spectral lines to iron nuclei in octahedral sublattice and one spectral line to irons in tetrahedral sublattice

Nuclear magnetic resonance of 57Fe in Al-, Ga- and Ti-substituted magnetite above Verwey temperature

Magnetite single crystals with Al, Ga and Ti substitutions were measured by means of 57Fe NMR (NMR) technique. Satellite structure of NMR spectra well above the Verwey temp. was detected and analyzed to obtain information on the distribution of substituting cations on iron sublattices. It was confirmed that Al and Ti enter iron octahedral B-sites. Ga strongly prefers tetrahedral A-sites, nevertheless a low presence of Ga cations in B-sites was detected. [on SciFinder (R)

Age structure and growth of Bufo verrucosissimus (Amphibia, Anura, Bufonidae) in the Caucasian State Nature Biosphere Reserve (Russia) at the end of the XX century

Bufo verrucosissimus is an endangered species in the Russian Federation. One of the largest protected areas where B. verrucosissimus is preserved is the Caucasian State Nature Biosphere Reserve. The paper presents data on age structure and growth of B. verrucosissimus collected in the Caucasian State Nature Biosphere Reserve in 1987–1990 and stored in the collection of Sochi National Park. The age of 16 females and 51 males was determined using the method of skeletochronology. The age of adult females was 6–10 years (on average 7.9 years), and males 2–9 years (on average 5.8 years). Females were statistically significantly superior to males in average age. In terms of body length, significant differences between males and females where noted in groups of seven- and ten-year-old animals. The body length of studied animals (60.8–116.4 mm for females and 61.2–86.3 mm for males) corresponds to the size of adult toads from other localities in the North Caucasus. Females grow evenly throughout their lives, while the growth of males slows down significantly after reaching puberty. Males were able to reach the maximum body length faster than females (the growth coefficient was 0.722 for males and 0.163 for females). According to the von Bertalanffy equation, the maximum possible body length was 130.9 mm for females and 74.6 mm for males