Fullerene pipes

Single-wall fullerene nanotubes were converted from nearly endless, highly tangled ropes into short, open-ended pipes that behave as individual macromolecules. Raw nanotube material was purified in large batches, and the ropes were cut into 100- to 300-nanometer lengths. The resulting pieces formed a stable colloidal suspension in water with the help of surfactants. These suspensions permit a variety of manipulations, such as sorting by length, derivatization, and tethering to gold surfaces.     

Circular polarization in star- formation regions: implications for biomolecular homochirality

Strong infrared circular polarization resulting from dust scattering in reflection nebulae in the Orion OMC-1 star-formation region has been observed. Circular polarization at shorter wavelengths might have been important in inducing chiral asymmetry in interstellar organic molecules that could be subsequently delivered to the early Earth by comets, interplanetary dust particles, or meteors. This could account for the excess of L-amino acids found in the Murchison meteorite and could explain the origin of the homochirality of biological molecules.     

Changes in urinary and plasma oestrone sulphate concentrations after induction of foetal death in mares at 45 days of gestation

Foetal death was induced in 10 Standardbred mares at day 45 of gestation by injecting 20 to 45 ml of hypertonic (24% W/V) saline into the conceptus at surgery. Ten mares underwent sham treatment and acted as controls. Blood and urine samples were collected every other day between days 30 and 45 post ovulation and at 0, 3 and 6 h relative to the infusion of saline in the treated mares, or sham treatment in control mares. Blood and urine samples were then collected daily between days 46 and 55 post ovulation. Urine oestrone sulphate (E1S) concentrations, measured by radioimmunoassay, increased between day 34 and day 36 of gestation in treated and control groups. In mares in which foetal death was induced, urine E1S concentrations declined post-operatively and were significantly (p less than .05) lower than controls by day 50. In plasma, E1S concentrations showed a major increase between days 36 and 40 in both groups. This was followed by a rapid decline after treatment in saline-injected mares, so that by day 48 plasma E1S concentrations in treated mares were significantly (P less than .05) lower than the controls. The results show that urinary and plasma E1S concentrations rise rapidly during early pregnancy, and are associated with a viable foetus after day 45 of pregnancy.     

Reproductive performance of Thoroughbred mares on six commercial stud farms

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.     

In planta transient expression as a system for genetic and biochemical analyses of chlorophyll biosynthesis

Background  

Mg chelatase is a multi-subunit enzyme that catalyses the first committed step of chlorophyll biosynthesis. Studies in higher plants and algae indicate that the Mg chelatase reaction product, Mg-protoporphyrin IX plays an essential role in nuclear-plastid interactions. A number of Mg chelatase mutants have been isolated from higher plants, including semi-dominant alleles of ChlI, the gene encoding the I subunit of the enzyme. To investigate the function of higher plant CHLI, bacterial orthologues have been engineered to carry analogous amino acid substitutions to the higher plant mutations and the phenotypes examined through in vitro characterization of heterologously produced proteins. Here, we demonstrate the utility of a transient expression system in Nicotiana benthamiana for rapidly assaying mutant variants of the maize CHLI protein in vivo.