Hematology, plasma chemistry, and bacteriology of wild Tundra Swans (Cygnus columbianus) in Alaska

Blood and cloacal swabs were collected from 100 (66 female, 34 male) wild Tundra Swans (Cygnus columbianus) molting in northwestern Alaska, USA, 25-28 July 2008, to establish hematologic and serum chemistry reference values and to isolate enteric Salmonella spp. and Escherichia coli O157:H7. Plasma biochemistry and hematology values did not vary significantly by sex or age. Tundra swans had high levels of creatine kinase, lactate dehydrogenase, amylase, and alkaline phosphatase compared with some other avian species (values were up to 7 times greater), possibly indicating capture myopathy. However, concentrations were much lower (up to 8 times lower) than in other waterfowl exposed to similar or more intensive capture methods. White blood cell count and hematocrit values were similar to other waterfowl species, and enteric Salmonella spp. and E. coli O157:H7 were not present among birds sampled. Our data provide the first biochemical, hematologic, and bacteriologic reference values for wild Tundra Swans.     

Effects of UV-B radiation on the structural and physiological diversity of bacterioneuston and bacterioplankton

The effects of UV radiation (UVR) on estuarine bacterioneuston and bacterioplankton were assessed in microcosm experiments. Bacterial abundance and DNA synthesis were more affected in bacterioplankton. Protein synthesis was more inhibited in bacterioneuston. Community analysis indicated that UVR has the potential to select resistant bacteria (e.g., Gammaproteobacteria), particularly abundant in bacterioneuston.     

Use of statistical tools in the study of the conditions of predation of Duddingtonia flagrans versus Panagrellus sp

The objective of the present work was to study the conditions of predation of Duddingtonia flagrans conidia versus Panagrellus sp using response surface methodology. Conidia of D. flagrans (AC001) isolate were transferred into water-agar (WA) culture media at different pHs and different concentrations defined according to Central Composite Design (CCD). Five different concentrations of D. flagrans conidia: (1292, 500, 1000, 1500 and 1707) were used. For 2%WA media were used the following pHs were used: 6.29, 6.5, 7.0, 7.5 and 7.71. The response of the design corresponded to the number of larvae (transformed to square root scale) observed at the end of the experiment (10 days). At the tenth day, the non predated larvae were recovered in the Petri dishes. The results showed that 2%WA media at pH 7.0 contributed to improve the predatory activity of conidia of D. flagrans, and therefore this tool may be used in future studies under laboratory and natural conditions.     

Testing Germination of Species for Hydroseeding Degraded Mediterranean Areas

The germination performance of native species and their suitability for a rapid erosion control are uncertain. Together with their relatively low commercial availability and high costs, these are still strong reasons preventing their common use in hydroseeding for restoration of Mediterranean degraded slopes, despite the increasing number of studies recommending it. In this study, 14 non‐native (commercial) and native herb and woody species were tested. Their germination performance was evaluated under laboratory (Petri dishes) and greenhouse conditions (seeds sown in target substrate). The results obtained were compared with the seedling densities in a Mediterranean quarry slope hydroseeded with the same species. In the laboratory, commercial species had a better germination performance than most native species, but this trend was not maintained in the greenhouse. Greenhouse tests were extended beyond spring and showed that many native species germinated better, or exclusively in autumn. Germination performance and success decreased, from laboratory to greenhouse and field conditions, for many species, but not for all. Relative to field performance, the predictive value of laboratory and greenhouse tests was poor, yet sowing on the target substrate under greenhouse conditions may be a better approach for certain native species. The main drawbacks revealed by native species in the present study included: (1) relatively slow germination; (2) seasonality; and (3) seed dormancy‐breaking requirements. The results suggest that these problems may be overcome through species selection, seed pre‐treatments, hydroseeding scheduling, and/or manipulation of seeding density and relative species proportion.     

Sex-linked mitochondrial behavior during early embryo development in Ruditapes philippinarum (Bivalvia Veneridae) a species with the Doubly Uniparental Inheritance (DUI) of mitochondria

In most metazoans mitochondria are inherited maternally. However, in some bivalve molluscs, two mitochondrial lineages are present: one transmitted through females (F-type), the other through males (M-type). This unique system is called Doubly Uniparental Inheritance (DUI) of mitochondria. In DUI species, M-type mitochondria have to invade the germ line of male embryos during development, otherwise sperm would transmit F-type mtDNA and DUI would fail. The mechanisms by which sperm mitochondria enter the germ line are still unknown. To address this question, we traced the movement of spermatozoon mitochondria (M-type) in embryos of the DUI species Ruditapes philippinarum by fertilizing eggs with sperm stained with the mitochondrial-specific vital dye MitoTracker Green. As in Mytilus DUI species, in R. philippinarum the distribution of sperm mitochondria follows two different patterns: an aggregated one in which these organelles locate near the first cleavage furrow, and a dispersed one in which sperm mitochondria are scattered. The presence of the two mitochondrial patterns in these taxa, together with their absence in species with Strictly Maternal Inheritance (SMI), confirms that their occurrence is related to DUI. Moreover, a Real-Time qPCR analysis showed that neither M-type nor F-type mitochondria undergo replication boosts in the earliest embryo development. This is the first study on sex-linked mtDNA copy number carried out by qPCR analysis on embryos of a DUI species and the first time the segregation patterns of sperm mitochondria are described in a DUI system other than Mytilus.     

A 28,000 years old Cro-Magnon mtDNA sequence differs from all potentially contaminating modern sequences

Background

DNA sequences from ancient speciments may in fact result from undetected contamination of the ancient specimens by modern DNA, and the problem is particularly challenging in studies of human fossils. Doubts on the authenticity of the available sequences have so far hampered genetic comparisons between anatomically archaic (Neandertal) and early modern (Cro-Magnoid) Europeans.

Methodology/Principal Findings

We typed the mitochondrial DNA (mtDNA) hypervariable region I in a 28,000 years old Cro-Magnoid individual from the Paglicci cave, in Italy (Paglicci 23) and in all the people who had contact with the sample since its discovery in 2003. The Paglicci 23 sequence, determined through the analysis of 152 clones, is the Cambridge reference sequence, and cannot possibly reflect contamination because it differs from all potentially contaminating modern sequences.

Conclusions/Significance:

The Paglicci 23 individual carried a mtDNA sequence that is still common in Europe, and which radically differs from those of the almost contemporary Neandertals, demonstrating a genealogical continuity across 28,000 years, from Cro-Magnoid to modern Europeans. Because all potential sources of modern DNA contamination are known, the Paglicci 23 sample will offer a unique opportunity to get insight for the first time into the nuclear genes of early modern Europeans.     

Ligand binding to truncated hemoglobin N from Mycobacterium tuberculosis is strongly modulated by the interplay between the distal heme pocket residues and internal water

The survival of Mycobacterium tuberculosis requires detoxification of host *NO. Oxygenated Mycobacterium tuberculosis truncated hemoglobin N catalyzes the rapid oxidation of nitric oxide to innocuous nitrate with a second-order rate constant (k'(NOD) approximately 745 x 10(6) m(-1) x s(-1)), which is approximately 15-fold faster than the reaction of horse heart myoglobin. We ask what aspects of structure and/or dynamics give rise to this enhanced reactivity. A first step is to expose what controls ligand/substrate binding to the heme. We present evidence that the main barrier to ligand binding to deoxy-truncated hemoglobin N (deoxy-trHbN) is the displacement of a distal cavity water molecule, which is mainly stabilized by residue Tyr(B10) but not coordinated to the heme iron. As observed in the Tyr(B10)/Gln(E11) apolar mutants, once this kinetic barrier is lowered, CO and O(2) binding is very rapid with rates approaching 1-2 x 10(9) m(-1) x s(-1). These large values almost certainly represent the upper limit for ligand binding to a heme protein and also indicate that the iron atom in trHbN is highly reactive. Kinetic measurements on the photoproduct of the *NO derivative of met-trHbN, where both the *NO and water can be directly followed, revealed that water rebinding is quite fast (approximately 1.49 x 10(8) s(-1)) and is responsible for the low geminate yield in trHbN. Molecular dynamics simulations, performed with trHbN and its distal mutants, indicated that in the absence of a distal water molecule, ligand access to the heme iron is not hindered. They also showed that a water molecule is stabilized next to the heme iron through hydrogen-bonding with Tyr(B10) and Gln(E11).