ARTIFICIAL INTERSPECIFIC HYBRIDIZATION IN RUELLIA (ACANTHACEAE)

Observations were made on the morphology, seed fertility, pollen viability and meiotic configurations of 22 different interspecific hybrids of 12 North American taxa representative of 3 sections of Ruellia. The hybrids were classified as (1) fully vigorous and fertile; (2) vigorous but with reduced fertility; (3) reduced vigor and fertility; (4) weak and sterile. Hybrids showed meiotic irregularities in microsporogenesis: univalents, chains, precocious separation of bivalents, nondisjunction, and micronuclei were commonly observed. Interspecific pollinations within sect. Dipteracanthus resulted in fertile or partially sterile F₁ hybrids. Intersectional crosses produced partially or completely sterile hybrids or failed. Assuming that crossability is correlated with degree of evolutionary relationship, the parental species are interpreted in genecological terms to be grouped in polytypic ecospecies. Hybridization experiments doubtless would be of value in clarifying relationships in tropical and subtropical species of Ruellia.     

Microbiology of Ensiled High-Moisture Corn

The effects of gaseous environment and temperature on the microbial populations of ensiled high-moisture corn were investigated. Molds, coliform bacteria, mesophilic aerobic bacteria, and yeasts were enumerated at intervals during ensiling. The numbers of aerobic bacteria were similar in structures containing different concentrations of gas and held at different temperatures. Coliform bacteria could not be detected after 10 days of ensiling. Mold numbers were relatively low, but were important in the deterioration of corn at the surface of the silos. Yeast and bacterial numbers increased rapidly following an initial aeration period, but no increase was observed after a second aeration series. Lack of a growth response to the second aeration series is believed related to the depletion of an assimilable carbon source.     

Book Reviews

The findings in and experiences with 19 consecutive patients subjected to open mitral valve surgery are described. All patients underwent a right-heart catheterization. In order to exclude multivalvular heart disease, a left-heart catheterization was performed in 10 patients and angiographic studies of the aortic valve area in 12. Pulmonary function studies were performed on 11 patients. The FEV (0.75 sec.) and the MMFR were found to correlate well with existing pulmonary reserves.Fourteen of the 19 patients subjected to open mitral valve surgery survived the operation and have been followed up for three months to 2½ years. Four patients had a mitral valvuloplasty. Three of these four have deteriorated and will require a valvular replacement. Ten of 15 patients subjected to a mitral valve replacement are alive; five of these 10 have had signs and symptoms indicating peripheral embolization. Mitral valvuloplasty is preferable to a valvular replacement as far as embolic complications are concerned, while valvular replacements result in a more perfect and lasting hemodynamic repair. The high incidence of peripheral embolization following valvular replacements focuses attention on the need for improved mitral valve prostheses.     

Failure of spermatozoa from T/t mice to fertilize in vitro is overcome by zona drilling

Failure of epididymal spermatozoa from T/t mutant mice, but not from t/t individuals, to fertilize oocytes in vitro was partially overcome by opening a small aperture in the zona pellucida with acidified Tyrode's solution to permit direct access of the spermatozoon to the vitellus. This study provides a model system to evaluate requirements for successful zona drilling in the treatment of human infertility and further insights into the effects of the t complex on sperm fertility.     

A comparison of sperm morphology and silver nitrate staining characteristics in the domestic ferret and the black-footed ferret

Ejaculated sperm from the domestic ferret (Mustela putorius furo) and the black-footed ferret (Mustela nigripes) were compared for differences in morphological abnormalities and argentophilic protein distribution. Thawed domestic ferret sperm was also compared to fresh sperm to determine whether there were any effects on cell morphology due to cryopreservation. There were statistically significant differences between the two species of ferret in two of the categories scored. The domestic ferret had a higher frequency of cells that were bent in the midpiece and in the principal piece, and a higher frequency of headless and tailless cells when compared to the black-footed ferret. There were no statistically significant differences in cell morphology between the fresh and cryopreserved ejaculates of the domestic ferret employing a standard egg yolk cryoextender. Silver nitrate staining distribution was different between the two species in both the head and tail region.