STS markers linked to the Rf 1 fertility restorer gene of cotton

Marker-assisted selection (MAS) can accelerate the process of plant breeding, and sequence-tagged site (STS) markers are highly specific for regions of DNA being used for MAS. The objective of this research was to develop STS markers tightly linked with Rf₁, the fertility restoring gene for cytoplasmic male sterility (CMS) in cotton (Gossypium hirsutum L.). Bulked segregant analysis was employed to screen for Rf₁-linked RAPD markers in a backcross population. Four RAPD markers were identified, three of which co-segregated with Rf₁ (UBC147₁₄₀₀, UBC607₅₀₀, and UBC679₇₀₀). Another fragment, UBC169₈₀₀, co-segregated with the previously reported UBC169₇₀₀ in repulsion phase at a distance of 4.5 cM from Rf₁. A marker published by others (UBC659₁₅₀₀) mapped to 2.7 cM from Rf₁ and 1.8 cM from UBC169₈₀₀. Four sets of STS primer pairs were designed based on the RAPD fragment sequences. The primer pairs from the UBC147₁₄₀₀ and UBC607₅₀₀ fragments both amplified a single fragment specific to fertile plants. The UBC679₇₀₀ and UBC659₁₅₀₀ STS primer pairs each amplified one fragment specific to fertile plants and a monomorphic fragment. These four Rf₁-linked STS markers were also present in the Rf₁ donor species G. harknessii (D_2-2). The three primer pairs that produced co-segregating STS markers also amplified fragments from G. trilobum (D₈). However, the D₈ fragment amplified by the UBC147₁₄₀₀ STS primers was larger than that from D_2-2, and G. trilobum does not restore fertility to CMS-D2-2 lines. These STS markers will be useful in the development of restorer parental lines in cotton CMS breeding efforts.     

Identification of the lower baseplate protein as the antireceptor of the temperate lactococcal bacteriophages TP901-1 and Tuc2009

The first step in the infection process of tailed phages is recognition and binding to the host receptor. This interaction is mediated by the phage antireceptor located in the distal tail structure. The temperate Lactococcus lactis phage TP901-1 belongs to the P335 species of the Siphoviridae family, which also includes the related phage Tuc2009. The distal tail structure of TP901-1 is well characterized and contains a double-disk baseplate and a central tail fiber. The structural tail proteins of TP901-1 and Tuc2009 are highly similar, but the phages have different host ranges and must therefore encode different antireceptors. In order to identify the antireceptors of TP901-1 and Tuc2009, a chimeric phage was generated in which the gene encoding the TP901-1 lower baseplate protein (bppL(TP901-1)) was exchanged with the analogous gene (orf53(2009)) of phage Tuc2009. The chimeric phage (TP901-1C) infected the Tuc2009 host strain efficiently and thus displayed an altered host range compared to TP901-1. Genomic analysis and sequencing verified that TP901-1C is a TP901-1 derivative containing the orf53(2009) gene in exchange for bppL(TP901-1); however, a new sequence in the late promoter region was also discovered. Protein analysis confirmed that TP901-1C contains ORF53(2009) and not the lower baseplate protein BppL(TP901-1), and it was concluded that BppL(TP901-1) and ORF53(2009) constitute antireceptor proteins of TP901-1 and Tuc2009, respectively. Electron micrographs revealed altered baseplate morphology of TP901-1C compared to that of the parental phage.     

Alterations in carbohydrate metabolism and its regulation in PPARalpha null mouse hearts

Although a shift from fatty acids (FAs) to carbohydrates (CHOs) is considered beneficial for the diseased heart, it is unclear why subjects with FA beta-oxidation defects are prone to cardiac decompensation under stress conditions. The present study investigated potential alterations in the myocardial utilization of CHOs for energy production and anaplerosis in 12-wk-old peroxisome proliferator-activating receptor-alpha (PPARalpha) null mice (a model of FA beta-oxidation defects). Carbon-13 methodology was used to assess substrate flux through energy-yielding pathways in hearts perfused ex vivo at two workloads with a physiological substrate mixture mimicking the fed state, and real-time RT-quantitative polymerase chain reaction was used to document the expression of selected metabolic genes. When compared with that from control C57BL/6 mice, isolated working hearts from PPARalpha null mice displayed an impaired capacity to withstand a rise in preload (mimicking an increased venous return as it occurs during exercise) as reflected by a 20% decline in the aortic flow rate. At the metabolic level, beyond the expected shift from FA (5-fold down) to CHO (1.5-fold up; P < 0.001) at both preloads, PPARalpha null hearts also displayed 1) a significantly greater contribution of exogenous lactate and glucose and/or glycogen (2-fold up) to endogenous pyruvate formation, whereas that of exogenous pyruvate remained unchanged and 2) marginal alterations in citric acid cycle-related parameters. The lactate production rate was the only measured parameter that was affected differently by preloads in control and PPARalpha null mouse hearts, suggesting a restricted reserve for the latter hearts to enhance glycolysis when the energy demand is increased. Alterations in the expression of some glycolysis-related genes suggest potential mechanisms involved in this defective CHO metabolism. Collectively, our data highlight the importance of metabolic alterations in CHO metabolism associated with FA oxidation defects as a factor that may predispose the heart to decompensation under stress conditions even in the fed state.     

Initial Intensive Care in an Accident and Emergency Department

The work in the resuscitation room is initial intensive care. This must be always available independent of inpatient resources. This demands investment in adequate equipment and staffing. Much of the work is medical rather than surgical and appropriate for physicians to treat. Our experience might help others to plan for the future.