Synthetic genetic polymers capable of heredity and evolution

Genetic information storage and processing rely on just two polymers, DNA and RNA, yet whether their role reflects evolutionary history or fundamental functional constraints is currently unknown. With the use of polymerase evolution and design, we show that genetic information can be stored in and recovered from six alternative genetic polymers based on simple nucleic acid architectures not found in nature [xeno-nucleic acids (XNAs)]. We also select XNA aptamers, which bind their targets with high affinity and specificity, demonstrating that beyond heredity, specific XNAs have the capacity for Darwinian evolution and folding into defined structures. Thus, heredity and evolution, two hallmarks of life, are not limited to DNA and RNA but are likely to be emergent properties of polymers capable of information storage.     

Hematologic responses in llamas with experimentally-induced iron deficiency anemia

Hematologic abnormalities consistent with iron deficiency anemia were experimentally induced in two healthy llamas by repeated phlebotomy. Hematologic abnormalities included erythrocyte microcytosis and hypochromia, decreased hemoglobin concentration, hypoferremia, and decreased transferrin saturation. Erythrocyte volume distribution histograms were more sensitive than mean corpuscular volume values for detection of microcytosis. Hypochromia, which was often eccentric, was morphologically observed on Wright-Giemsa-stained blood films. Frequent folded erythrocytes and dacryocytes were also noted on the blood films. Hematologic abnormalities resolved rapidly after cessation of blood removal, without parenteral iron supplementation.     

Revised phylogenetic relationships among herpesviruses isolated from sturgeons

Initial phylogenetic comparisons based on a region of the DNA polymerase of seven herpes-like viruses found in sturgeons in North America and Europe indicated the presence of three distinct clades. A revised phylogenetic analysis of the same viruses, based on corrected DNA polymerase sequences and newly obtained sequence data from the putative ATP subunit of the terminase gene, indicate only two clades. These two clades correspond to the historical designations given to these herpes-like viruses from white sturgeon Acipenser transmontanus: white sturgeon herpesvirus type 1 (WSHV-1) and type 2 (WSHV-2). The identification of putative terminase gene sequences for all seven herpes-like viruses from sturgeons confirms their affinity with the family Herpesviridae (because this gene is unique to herpesviruses) and more distantly with T4-like bacteriophages. The two clades of sturgeon herpesviruses are therefore appropriately designated as Acipenserid herpesviruses 1 and 2, which correspond to the previous common names of white sturgeon herpesvirus types 1 and 2.     

Identification and characterisation of coding tandem repeat variants in incA gene of Chlamydophila pecorum

Bacteria of the family Chlamydiaceae are obligate intracellular pathogens of human and animals. Chlamydophila pecorum is associated with different pathological conditions in ruminants, swine and koala. To characterize a coding tandem repeat (CTR) identified at the 3' end of incA gene of C. pecorum, 51 strains of different chlamydial species were examined. The CTR were observed in 18 of 18 tested C. pecorum isolates including symptomatic and asymptomatic animals from diverse geographical origins. The CTR were also found in two strains of C. abortus respectively isolated from faeces from a healthy ewe and from a goat belonging to asymptomatic herds, but were absent in C. abortus strains isolated from clinical disease specimens, and in tested strains of C. psittaci, C. caviae, C. felis and C. trachomatis. The number of CTR repeats is variable and encode several motifs that are rich in alanine and proline. The CTR-derived variable structure of incA, which encode the Chlamydiaceae-specific type III secreted inclusion membrane protein, IncA, may be involved in the adaptation of C. pecorum to its environment by allowing it to persist in the host cell.     

Association of severity of enteric granulomatous inflammation with disseminated Mycobacterium avium subspecies paratuberculosis infection and antemortem test results for paratuberculosis in dairy cows

Disseminated infection (DI) of Mycobacterium avium subspecies paratuberculosis (MAP) in cattle may impair cow health, potentiate spread of disease, and is a potential food-safety risk. The objectives of this study were to determine the association between severity of histologic enteric lesions and the occurrence of DI, clinical signs, and positive fecal culture and serum ELISA results. Bacteriologic fecal culture and serum ELISA were performed on 40 dairy cows from MAP-infected herds. Cows were classified as having DI if MAP was isolated from any of 11 extra-intestinal tissues collected postmortem. A grade of 0-3, corresponding to the severity of histologically evident granulomatous inflammation was determined for sections of ileum, jejunum, mesenteric lymph node, and ileocolic lymph node. An overall intestinal inflammation (OII) grade of 0-3 was assigned to each cow. The proportion of cows with DI increased with tissue-specific lesion grade and OII grade. All cows with grade 3 inflammation in any single tissue had DI, however, some cows with DI had grade 1 inflammation or no lesions. In general, there was a positive association between OII grade and clinical signs, gross enteric lesions, and positive ELISA and fecal culture results. However, 12% of OII grade 0 cows had clinical signs (explained by other conditions recognized with necropsy), and the proportion of positive ELISA results was lower for OII grade 3 cows relative to grade 2 cows. Although MAP dissemination may occur early in the disease process, histopathology of intestinal tissues may be used to detect a substantial proportion of DI cows.     

Disturbance has benefits as well as costs for fragmented populations of a cryptic grassland reptile

Landscape Ecology - Conservation practitioners face complex decisions about the management of spatial and temporal disturbance regimes when disturbance plays a significant role in the dynamics of...     

Involvement of microbial respiratory pathogens in acute interstitial pneumonia in feedlot cattle

OBJECTIVE: To evaluate viral and bacterial respiratory pathogens and Mycoplasma spp isolated from lung tissues of cattle with acute interstitial pneumonia (AIP) and cattle that had died as a result of other causes. SAMPLE POPULATION: 186 samples of lung tissues collected from cattle housed in 14 feedlots in the western United States. PROCEDURE: Lung tissues were collected during routine postmortem examination and submitted for histologic, microbiologic, and toxicologic examinations. Histologic diagnoses were categorized for AIP, bronchopneumonia (BP), control samples (no evidence of disease), and other disorders. RESULTS: Cattle affected with AIP had been in feedlots for a mean of 1272 days before death, which was longer than cattle with BP and control cattle. Detection of a viral respiratory pathogen (eg, bovine respiratory syncytial virus [BRSV], bovine viral diarrhea virus, bovine herpesvirus 1, or parainfluenza virus 3) was not associated with histologic category of lung tissues. Bovine respiratory syncytial virus was detected in 8.3% of AIP samples and 24.0% of control samples. Histologic category was associated with isolation of an aerobic bacterial agent and Mycoplasma spp. Cattle with BP were at greatest risk for isolation of an aerobic bacterial agent and Mycoplasma spp. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results suggests that AIP in feedlot cattle is not a consequence of infection with BRSV. The increased, risk of isolation of an aerobic bacterial agent from cattle with AIP, compared with control cattle, may indicate a causal role or an opportunistic infection that follows development of AIP.     

GENETICS. The Human Variome Project

An ambitious plan to collect, curate, and make accessible information on genetic variations affecting human health is beginning to be realized.