Comparison of the stability of glutathione and related synthetic tetrapeptides by HPLC and capillary electrophoresis.

Glutathione and related peptides are interesting targets as protectors of biological systems against an oxidative injury. Two novel glutathione analogues, UPF1 and UPF15, have been designed and synthesised. As a result of different reactions taking place, the thiol-containing compounds oxidise to disulfides. In this study, the stability of UPF1, UPF15 and glutathione in various solutions was investigated by using HPLC and CE. The results showed that UPF1 and UPF15 are powerful hydroxyl radical scavengers and their dimerisation process velocity is higher than that of glutathione.     

A new species of “sangre de drago” (Croton section Cyclostigma, Euphorbiaceae) from coastal Ecuador

Croton churutensis is described as a new species ofCroton sectionCyclostigma endemic to lowland deciduous forests in coastal Ecuador. Its red latex is used locally in Guayas Province to treat wounds, stomach ulcers, and some skin conditions caused by fungal infections. The new species differs from its closest apparent relative,Croton hibiscifolius, in its arching-pendent inflorescences, short-pedicellate female flowers with quadrifid stigmas, more numerous stamens, laciniate stipules, and lower elevation habitat.     

Buccal swab: A tissue sampling method for refinement of experimental procedures involving rainbow trout

Buccal swabbing is a minimally invasive method to obtain DNA and biological material from humans and animals, including fish. Reports on buccal swabbing in fish are few and only for a limited number of species. Rainbow trout (Oncorhynchus mykiss) is an important animal model and because the yield of DNA may vary among and within different species in individuals of different sizes, it was selected as useful to optimize the buccal DNA collection in this species. Different storage methods were evaluated, aimed at DNA preservation by limiting DNA degradation and bacterial growth, using commonly available and inexpensive reagents. DNA quality was also tested by amplification of a single‐copy nuclear gene and a mitochondrial gene. The results suggest that ethanol is the best storage choice for buccal swab sampling in fish genetic studies, as well as suitable for small‐bodied rainbow trout.     

Bone morphogenetic proteins 4 and 2/7 induce osteogenic differentiation of mouse skin derived fibroblast and dermal papilla cells

Heterotopic ossification is a pathological condition in which bone forms outside the skeletal system. It can also occur in skin, which is the case in some genetic disorders. In addition to precursor cells and the appropriate tissue environment, heterotopic ossification requires inductive signals such as bone morphogenetic proteins (BMP). BMPs are growth and differentiation factors that have the ability to induce cartilage and bone formation in ectopic sites. The objective of this study is to explore the effect of the BMP-4 homodimer and BMP-2/7 heterodimer on the osteogenic differentiation of primary mouse skin fibroblasts and hair follicle dermal papilla (DP) cells. Osteogenic differentiation was induced by osteogenic induction medium (OS) containing 10 nM dexamethasone. The effect of BMP-4 and BMP-2/7 was studied using alkaline phosphatase (ALP) and calcium assays after 1.5, 3 and 5 weeks of differentiation. Fibroblasts and DP cells were able to differentiate into osteoblast-like matrix mineralizing cells. The first visible sign of differentiation was the change of morphology from rounded to more spindle-shaped cells. BMP-4 and BMP-2/7 exposure elevated ALP activity and calcium production significantly more than OS alone. The osteogenic response to BMP-4 and BMP-2/7 was similar in fibroblasts, whereas, in DP cells, BMP-2/7 was more potent than BMP-4. OS alone could not induce osteogenic differentiation in DP cells. Clear and consistent results show that dermal fibroblasts and stem cells from the dermal papilla were capable of osteogenic differentiation. The BMP-2/7 heterodimer was significantly more effective on hair follicular dermal stem cell differentiation.     

Penetration of membrane-containing double-stranded-DNA bacteriophage PM2 into Pseudoalteromonas hosts

The icosahedral bacteriophage PM2 has a circular double-stranded DNA (dsDNA) genome and an internal lipid membrane. It is the only representative of the Corticoviridae family. How the circular supercoiled genome residing inside the viral membrane is translocated into the gram-negative marine Pseudoalteromonas host has been an intriguing question. Here we demonstrate that after binding of the virus to an abundant cell surface receptor, the protein coat is most probably dissociated. During the infection process, the host cell outer membrane becomes transiently permeable to lipophilic gramicidin D molecules proposing fusion with the viral membrane. One of the components of the internal viral lipid core particle is the integral membrane protein P7, with muralytic activity that apparently aids the process of peptidoglycan penetration. Entry of the virion also causes a limited depolarization of the cytoplasmic membrane. These phenomena differ considerably from those observed in the entry process of bacteriophage PRD1, a dsDNA virus, which uses its internal membrane to make a cell envelope-penetrating tubular structure.     

IgG from patients with liver diseases inhibit mitochondrial respiration in permeabilized oxidative muscle cells: Impaired function of intracellular energetic units?

The effect of IgG purified from the sera of healthy persons and patients with primary biliary cirrhosis (PBC) and chronic hepatitis (CH) on ADP dependent respiration (oxidative phosphorylation) in skinned muscle fibers from rat oxidative muscles (heart and M. soleus) and glycolytic skeletal muscle (M. gastrocnemius) was studied. The results show that IgG from three different sources inhibited the rate of respiration by 13, 44 and 42%, respectively, these effects being equally expressed in both types of oxidative muscles, whereas no inhibition was observed in glycolytic muscle. The following washout of unbound IgG did not abolish the inhibition of respiration suggesting that the specific interaction of IgG with antigens had taken place. Laser confocal analysis revealed binding of IgG predominantly to the sarcomeric structures such as Z-disk and M-lines in the cardiomyocytes. The staining of IgG within Z-disks and intermitochondrial space coincided throughout the muscle cells so that transversally serial spaces, each containing mitochondria and adjacent sarcomere, became clearly visible. When the IgG from a CH patient was incubated with the skinned myocardial fibers of the desmin knockout mice, its binding to Z-disks and the sarcomeric area was found to be similar to that in normal cardiac muscle. However, the transversal staining pattern was disintegrated, because of the slippage of the myofibrils in relation to each other and accumulation of mitochondria between them. These observations support the recent hypothesis that in oxidative muscles the mitochondria and adjacent sarcomeres form complexes, termed as the intracellular energetic units, ICEUs. Moreover, they indicate that human autoantibodies can be useful tools for localizing the proteins responsible for formation of ICEUs and modulation of their function. Thus, it appears that the proteins associated with the Z-disks and M-lines may participate in formation of ICEUs and that binding of IgG to these proteins decreases the access of exogenous adenine nucleotides to mitochondria, which manifests as decreased rate of ADP-dependent respiration.     

Patterns of vertical cyst distribution and survival in 100-year-old sediment archives of three spring dinoflagellate species from the Northern Baltic Sea

The history of expansion of bloom-forming cold water dinoflagellates in the Northern Baltic Sea was studied using 100-year-old sediment archives of their resting cysts. Vertical cyst distributions of Biecheleria baltica and Apocalathium malmogiense, two dinoflagellates indistinguishable by light microscopy and not recognized as distinct species in monitoring, and chain-forming Peridiniella catenata were analysed in Pb²¹⁰ and Cs¹³⁷ dated layers of a sediment core from deep, hypoxic accumulation bottoms of the Gulf of Finland. Cyst profiles showed that B. baltica and A. malmogiense were already present in the Baltic spring phytoplankton community at the beginning of the 20th century. This confirms that B. baltica, which was only recognized in the late 1980s, is a native species in the area. A drastic increase in B. baltica cyst concentrations in the 1930s to 1960s coincided with the acceleration of anthropogenic eutrophication. Large cyst deposits accumulated over several decades in the sediment which, by the 1980s, amounted to the seed stock necessary to inoculate dominant blooms. In the cyst records A. malmogiense always contributed a minor fraction of the two species. P. catenata had a relatively short cyst record in Gulf of Finland sediments despite demonstrated long-term presence in the plankton, which emphasizes that cyst-based historic surveys are not suitable for all cyst-forming dinoflagellates. This was corroborated by correspondence analyses of long-term plankton and cyst records which validated the trends from the sediment archive for B. baltica and A. malmogiense, but failed to do so for P. catenata. Germination experiments with 100-year-old cysts revealed a remarkable long-term survival capacity of A. malmogiense, making this species a suitable model for resurrection studies testing adaptation in heavily impacted systems such as the Baltic Sea.     

Tawny owl prey remains indicate differences in the dynamics of coastal and inland vole populations in southern Finland

Some studies suggest that mild winters decrease overwinter survival of small mammals or coincide with decreased cyclicity in vole numbers, whereas other studies suggest non-significant or positive relationships between mild winter conditions and vole population dynamics. We expect for the number of voles to be higher in the rich and low-lying habitats of the coastal areas than in the less fertile areas inland. We assume that this geographical difference in vole abundances is diminished by mild winters especially in low-lying habitats. We examine these relationships by generalized linear mixed models using prey remains of breeding tawny owls Strix aluco as a proxy for the abundance of voles. The higher number of small voles in the coastal area than in the inland area suggest that vole populations were denser in the coastal area. Vole populations of both areas were affected by winter weather conditions particularly in March, but these relationships differed between areas. The mild ends of winter with frequent fluctuations of the ambient temperature around the freezing point (“frost seesaw”) constrained significantly the coastal vole populations, while deep snow cover, in general after hard winters, was followed by significantly lowered number of voles only in the inland populations. Our results suggest that coastal vole populations are more vulnerable to mild winters than inland ones. We also show that tawny owl prey remains can be used in a meaningful way to study vole population dynamics.