Selection of buffalo bulls: Sexual behavior and its relationship to semen production and fertility

Forty-four buffalo bulls, used for artificial insemination, were studied to develop libido, mating ability and sexual behavior indices for selection purposes. For each index, 5 categories (i.e., excellent, very good, good, fair and poor) were established. The sexual behavior index was found to be more reliable than the libido and mating ability indices. Buffalo bulls in good to excellent categories were considered acceptable sires.

Reaction time, sexual aggressiveness, and scores of libido, mating ability and sexual behavior differed significantly among the various categories of the 3 indices. Libido significantly correlated with mating ability (r=0.89; P<0.001). Sexual behavior expressed significant relationship with age (r=0.41; P<0.01) and body weight (r=0.48; P<0.01), but was nonsignificant with the scrotal circumference (r=0.28; P>0.05) of buffalo bulls. However, these relationships were absent (P>0.05) in the acceptable sires. Semen production was correlated with sexual behavior in only the fair and poor categories of buffalo bulls (r=0.84; P<0.005). Sexual behavior had no relationship with the fertility rate of buffalo bulls (r=0.44; P>0.05). It is concluded that the sexual behavior index can be used successfully for the selection of buffalo bulls. Excellent- to good bulls should be used in an artificial breeding program if they qualify in the other selection indices.     

The nifY product of Klebsiella pneumoniae is associated with apodinitrogenase and dissociates upon activation with the iron-molybdenum cofactor.

Apodinitrogenase, which lacks the iron-molybdenum cofactor at its active site, is an oligomer that contains an additional protein not found in the active dinitrogenase tetramer. This associated protein in Klebsiella pneumoniae is shown to be the product of the nifY gene. When apodinitrogenase is activated by the addition of the iron-molybdenum cofactor, NifY dissociates from the apodinitrogenase complex. The conditions for this dissociation are described. Finally, there are aspects of the dissociation and insertion process in K. pneumoniae that are different from that in Azotobacter vinelandii.     

Electron microscope tomography of Balbiani Ring hnRNP substructure

Three-dimensional (3-D) reconstructions, by electron microscope tomography, of selectively stained, contrast enhanced Balbiani Ring (BR) hnRNP granules reveal a complex spatial arrangement of RNA-rich domains. This particulate substructure was examined by volume rendering computer graphics. Modeling the arrangement of RNA-rich domains is made difficult by apparent structural flexibility and/or heterogeneity of composition. Formulation of a consensus 3-D arrangement of RNA-rich domains will require an expanded data base of reconstructed BR granules and the development of new image manipulation and analysis techniques. This study demonstrates the potential for ultra-structural cell biology of combining several new techniques: selective nucleic acid staining, electron spectroscopic imaging to enhance contrast, electron microscope tomography and volume rendering computer graphics.Abbreviations BR Balbiani Ring - EMT electron microscope tomography - ESI electron spectroscopic imaging - hnRNP heterogeneous nuclear ribonucleoprotein - OA-B osmium ammine-B - kb kilobases by P.B. Moens     

Effect of supplemental oxygen on supramaximal exercise performance and recovery in cystic fibrosis

Shah, Ashish R., Thomas G. Keens, and David Gozal.Effect of supplemental oxygen on supramaximal exercise performance and recovery in cystic fibrosis. J. Appl.Physiol. 83(5): 1641-1647, 1997.The effects ofsupplemental O₂ on recovery fromsupramaximal exercise and subsequent performance remain unknown. Ifrecovery from exercise could be enhanced in individuals with chroniclung disease, subsequent supramaximal exercise performance could also be improved. Recovery from supramaximal exercise and subsequent supramaximal exercise performance were assessed after 10 min of breathing 100% O₂ or room air(RA) in 17 cystic fibrosis (CF) patients [25 ± 10 (SD) yrold, 53% men, forced expired volume in 1 s = 62 ± 21%predicted] and 17 normal subjects (25 ± 8 yr old, 59% men,forced expired volume in 1 s = 112 ± 15% predicted). Supramaximalperformance was assessed as the work of sustained bicycling at a loadof 130% of the maximum load achieved during a graded maximal exercise.Peak minute ventilation(E) andheart rate (HR) were lower in CF patients at the end of eachsupramaximal bout than in controls. In CF patients, single-exponentialtime decay constants indicated faster recovery of HR(_HR = 86 ± 8 and 73 ± 6 s in RA and O₂,respectively, P < 0.01). Similarly, fast and slow time constants of two-exponential equations providing thebest fit for ventilatory recovery were improved in CF patients duringO₂ breathing ( = 132.1 ± 10.5 vs. 82.5 ± 10.4 s; = 880.3 ± 300.1 vs. 368.6 ± 107.1 s,P < 0.01). However, no such improvements occurred in controls. Supramaximal performance after O₂ improved in CF patients (109 ± 6% of the 1st bout after O₂ vs. 94 ± 6% in RA, P < 0.01).O₂ supplementation had no effect on subsequent performance in controls (97 ± 3% inO₂ vs. 93 ± 3% in RA). Weconclude that supplemental O₂after a short bout of supramaximal exercise accelerates recovery andpreserves subsequent supramaximal performance in patients with CF.

     

Increased cathepsin D-like activity in cortex, tubules, and glomeruli isolated from rats with experimental nephrotic syndrome.

We have examined the activity and distribution of cathepsin D (EC 3.4.23.5), a major renal lysosomal endoproteinase, in the various anatomical and functional areas of normal rat kidney. Cathepsin D-like activities (delta A280/h per mg of protein) in normal rat tissues were: cortex, 0.78 +/- 0.05, n = 37; medulla, 0.62 +/- 0.03, n = 12; papilla, 0.63 +/- 0.04, n = 12; tubules, 0.74 +/- 0.04, n = 28; glomeruli, 0.59 +/- 0.03, n = 28; and liver, 0.41 +/- 0.02, n = 28. Enzyme activity was maximal at pH 3.0-3.5 and inhibited more than 90% by pepstatin (6.7 micrograms/ml), suggesting that the enzyme is cathepsin D. In subsequent experiments we measured cathepsin D-like activity in cortex, tubules and glomeruli isolated from rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. Treated animals (15 mg of PAN/100g body wt., intraperitoneally) developed proteinuria beginning 4 days after injection and exceeding 900 mg/24h on day 9. In two separate experiments involving 52 animals we observed a significant increase in cathepsin D-like activity in cortex (+82.7%), tubules (+109.6%) and glomeruli (+54.7%) isolated from PAN-treated rats killed during marked proteinuria (day 9, mean total urinary protein excretion: 937 +/- 94 mg/24h). This increase was observed whether the activity was expressed per mg of DNA or per mg of protein. Increased cathepsin D-like activity was first observed in cortex and tubules coincident with the onset of proteinurea (day 4, mean total urinary protein excretion: 112 +/- 23 mg/24h). In contrast with the significant elevation of renal cathepsin D-like activity, the activity (nmol/h per mg of protein) of alpha-L-fucosidase (EC 3.2.1.51), a non-proteolytic enzyme, was markedly decreased in the identical samples used for the measurement of cathepsin D-like activity: cortex (-46.4%); tubules (-46.1%); and glomeruli (-38.5%). In addition to changes in renal enzyme activities, PAN-treated rats excreted large amounts of cathepsin D-like activity in their urine (beginning on day 3) compared with nearly undetectable cathepsin D-like activity in the urine from control rats. The significant increases in glomerular and tubular cathepsin D activity may reflect an important role for this enzyme in the pathophysiology associated with PAN-induced nephrotic syndrome.     

Evidence for "twisted plane" undulations in golden hamster sperm tails

Motile spermatozoa from the golden hamster have been arrested by rapid freezing and then fixed with glutaraldehyde at low temperature after substitution with ethylene glycol. As far as can be judged, the flagellar waveforms thus stabilized are similar to those seen in living sperm; in contrast, fixation in glutaraldehyde, without prior freezing, induces agonal changes in flagellar conformation. The characteristics waveform after freeze substitution contains three bends. Approx. half of these flagella are entirely planar. The rest are three dimensional, with the third bend displaced in a regular way from the plane containing the proximal two bends. From the geometry of these flagella, it is concluded that the plane of action of a given bending cycle undergoes a clockwise twist (from a forward viewpoint) as the cycle is succeeded by new bending cycles. This "twisted plane" undulation is quite different from helical movement. The twisting seems to occur abruptly, between cycles, as if each bending cycle has a preferred plane of action. The mechanism underlying the twisting is uncertain. However, on the basis of the angular displacements between the preferred planes, and the findings from electron microscopy, the following idea is presented as a working hypothesis: that, if the most proximal plane of bending is topographically determined by peripheral doublet 1, then successive distal planes of action are influenced predominantly by doublets 2, 3, etc., in clockwise sequence. The merits and weaknesses of this hypothesis are discussed.     

Detection of vitamin B12 and pantothenic acid in cell exudates of blue-green algae

The blue-green algaeChroococcus, Oscillatoria and Nostoc, excrete vitamin B₁₂ and pantothenic acid in the culture filtrates during the phase of active growth. The excretion has an ecological significance.