A NEW CHONDRODYSTROPHIC MUTANT IN MICE : Electron Microscopy of Normal and Abnormal Chondrogenesis

The occurrence of a new mutation affecting cartilage and bone in mice is reported. The gene is lethal, shows autosomal recessive inheritance, and has high penetrance. It is not allelic to shorthead and probably not to phocomelia or achondroplasia. It results in a foreshortened face, cleft palate, defective trachea, and shortened long bones with flared metaphyses. Chondrocytes of epiphyseal cartilage from the mutant are not aligned in columns, and there is a decrease in the usual staining of the cartilage matrix. Electron microscope observations show large, wide collagen fibrils with "native" banding in the matrix of mutant cartilage, which are not present in normal cartilage. Possible explanations for the expression of this genetic disorder of cartilage development are put forward

Isolation of a Collagenase cDNA Clone and Measurement of Changing Collagenase mRNA Levels during Induction in Rabbit Synovial Fibroblasts.

To facilitate our studies on the mechanisms controlling collagenase production at a molecular level in rabbit synovial fibroblasts, we have constructed a cDNA library using mRNAs isolated from cells induced with crystals of monosodium urate monohydrate. We have screened this library with cDNA probes made from induced and control mRNA populations. From among 30 clones that hybridized preferentially to the induced-cell probe, 4 contained collagenase sequences. The largest, a clone of 650 base pairs, was identified by its ability to hybrid select a mRNA that could be translated in a cell-free system into a product that was precipitable with monospecific antibody to collagenase. Using this clone to probe blots of RNA from induced cells, we detected the appearance of a collagenase mRNA of 2.7 kilobases within 5 hr of addition of urate. The level of collagenase mRNA continued to increase for 35-40 hr, when it was 60 to 90 times more abundant in induced cells than in control cells. The increase in mRNA levels correlated with an increase in immunoreactive collagenase protein that was detectable in culture medium by 10 hr

The development and evaluation of exercises in meaningful word practice in grade one

Research chapter for this study will be found in Ash, Dorothea: "Development and evaluation of silent reading exercises in grade one" Thesis (Ed.M.)--Boston Universit

The development and evaluation of exercises in meaningful word practice in grade one

Research chapter for this study will be found in Ash, Dorothea: "Development and evaluation of silent reading exercises in grade one" Thesis (Ed.M.)--Boston Universit

BREEDING BEHAVIOR OF THE GRAY-BREASTED FLYCATCHER (LATHROTRICCUS GRISEIPECTUS) IN SOUTHWESTERN ECUADOR

Abstract ∙ Little is known about the nesting behavior of the Gray-breasted Flycatcher (Lathrotriccus griseipectus), a species listed as Vulnerable by the International Union for Conservation of Nature. In order to add fundamental information on the life history of this species, we recorded parental behavior at a nest in February–March 2010 in the Jorupe Reserve in southwestern Ecuador. Recordings were made on a tripod-mounted video camera and took place during part of the incubation and nestling stages. Both adults provisioned nestlings. We recorded 7.1 feeds per nestling-hour, with the highest average provisioning rates occurring from 12:00–13:00 h. Nestlings produced an average of 0.8 fecal sacs per nestling-hour. Nestlings fledged in quick succession shortly before 12:00 h on nestling-day 14.Resumen ∙ El cuidado parental del Mosquero Pechigrís (Lathrotriccus griseipectus) en el suroeste del Ecuador La biología reproductiva del Mosquero Pechigrís (Lathrotriccus griseipectus), una especie catalogada como “Vulnerable” por la Unión Internacional para la Conservación de la Naturaleza, es poco conocida. Con el fin de añadir datos básicos sobre la historia de vida del Mosquero Pechigrís, utilizamos una cámara de video para realizar observaciones de un nido ubicado en la Reserva Jorupe en el suroeste de Ecuador, entre febrero y marzo de 2010. Las grabaciones tuvieron lugar durante parte de las etapas de incubación y polluelo. Ambos adultos aprovisionaron polluelos. Registramos 7.1 alimentaciones de polluelo por hora, siendo las tasas de aprovisionamiento más altas de 12:00–13:00 h. Los polluelos produjeron un promedio de 0.8 sacos fecales por hora y polluelo. Los polluelos emplumaron en rápida sucesión poco antes del mediodía 14 días luego de la eclosión