The karyotype of Alligator mississippiensis,and chromosomal mapping of the ZFY/X homologue,Zfc

Comparative mapping studies of X-linked genes in mammals have provided insights into the evolution of the X chromosome. Many reptiles including the American alligator, Alligator mississippiensis, do not appear to possess heteromorphic sex chromosomes, and sex is determined by the incubation temperature of the egg during embryonic development. Mapping of homologues of mammalian X-linked genes in reptiles could lead to a greater understanding of the evolution of vertebrate sex chromosomes. One of the genes used in the mammalian mapping studies was ZFX, an X-linked copy of the human ZFY gene which was originally isolated as a candidate for the mammalian testis-determining factor (TDF). ZFX is X-linked in eutherians, but maps to two autosomal locations in marsupials and monotremes, close to other genes associated with the eutherian X. The alligator homologue of the ZFY/ZFX genes, Zfc, has been isolated and described previously. A detailed karyotype of A. mississippiensis is presented, together with chromosomal in situ hybridisation data localising the Zfc gene to chromosome 3. Further chromosomal mapping studies using eutherian X-linked genes may reveal conserved chromosomal regions in the alligator that have become part of the eutherian X chromosome during evolution.     

Treatment of burns casualties after fire at Bradford City football ground.

On 11 May 1985 the main stand of Bradford City Football Club caught fire. Within four minutes the stand was alight from end to end. Fifty three people were burnt to death and about 250 injured; 83 required admission to hospital, and 55 of these were treated by primary excision of their burns and skin grafting. In such disasters the help of staff from other hospitals and areas is essential. Patients should be assessed to see whether they have burns that will ultimately be fatal; if they have they should not be sent to regional burns units, where they would take up beds that could be used for patients with treatable burns. All districts should ensure that their plans for accidents in which burns injuries predominate are adequate.     

Effects of urbanization on streams of the Melbourne region, Victoria, Australia. I. Benthic macroinvertebrate communities

1. Macroinvertebrate community composition was assessed in small streams of the Melbourne region to test the effects of (a) urban density (catchment imperviousness 0–51%) and (b) stormwater drainage intensity (comparing the intensively drained metropolitan area with urban areas of the hinterland, which had open drains and some localized stormwater drainage).
2. Hinterland communities separated into two groups of sites correlating strongly with patterns of electrical conductivity (EC), basalt geology and annual rainfall. Community composition varied little in the high-EC, western group (imperviousness 0.2–1.2%), but in the eastern group it was strongly correlated with catchment imperviousness (0–12%), with lower taxon richness in more impervious catchments.
3. Metropolitan communities (imperviousness 1–51%) were all severely degraded, with high abundances of a few tolerant taxa. Community composition was poorly correlated with patterns of geology, rainfall or imperviousness. Differences between metropolitan and hinterland communities were well explained by patterns of biochemical oxygen demand and electrical conductivity, which were postulated to indicate the more efficient transport of pollutants to receiving streams by the metropolitan stormwater drainage system.
4. Degradation of macroinvertebrate community composition was well explained by urban density but intensive urban drainage increased degradation severely at even low urban densities. Quantification of relationships between imperviousness, drainage intensity and stream degradation can better inform the assessment, conservation and restoration of urban streams.     

Origin of regenerating Leydig cells in the testis of the adult rat

Summary Ethane dimethanesulphonate (EDS) was used as a specific cytotoxin to eliminate the Leydig cell population of the adult rat testis. Ultrastructural, morphometric and serum gonadotrophin and testosterone analysis was used to study the response of the intertubular tissue of the testis from 1 day to 10 weeks after EDS treatment. In control animals, the testis contained approximately 28 million Leydig cells and 8 million macrophages. Three to seven days after EDS treatment, Leydig cells were absent and serum testosterone was undetectable. Macrophage numbers increased three-fold by 3 days and returned to pretreatment values thereafter. At 2 and 3 weeks post-EDS, foetal-type Leydig cells (1–2 million per testis) appeared in proximity to perivascular and peritubular tissues, a feature also observed at 4 weeks when numerous such cells (15 million per testis) formed prominent clusters in perivascular and peritubular locations. Between 6 and 10 weeks after EDS treatment, the foetal-type Leydig cells were transformed morphologically into adult-type Leydig cells, they occupied central intertubular positions and their numbers were restored to pretreatment values. Regeneration of Leydig cells was reflected by elevated serum testosterone levels which returned towards the normal range. The results demonstrate the regenerative capacity of the testicular intertubular tissue and indicate a dual site of origin of Leydig cells which initially resemble foetal-type Leydig cells prior to establishing the adult-type Leydig cell population. The morphological pattern of Leydig cell regeneration suggests that in addition to gonadotrophic stimulation, local testicular factors from the seminiferous tubules may stimulate Leydig cell growth.     

Absence of uterokinetic effects of prostaglandin F 2 alpha on oxytocin-reactive uterus in the mare

In most cyclic females, prostaglandin F(2alpha) (PGF(2alpha)) triggers a uterine motility response resembling that of oxytocin (OT). To determine if PGF(2alpha) is a uterokinetic substance in the cycling mare, uterine motility was measured by intrauterine balloon technique in 12 conscious, normally cyclic mares. After 60 min of saline infusion, continuous intravenous (i.v.) infusion with OT (1 i.u./min) was followed by PGF(2alpha) (200 mug/min) for 60 min each. The experiment was repeated 3 wk later except with PGF(2alpha) preceeding OT. A second group of mares was administered OT (60 i.u.) either i.v., intramuscularly (i.m.), or intrauterinely (i.u.). Plasma samples were studied for progesterone concentration. Control uterine motility for the first group of mares was (mean +/- SEM) 545.83 +/- 45.10 mm(2). Significant (P<0.05) elevation in uterine motility was recorded for OT (1118.60 +/- 70.56 mm(2)) regardless if PGF(2alpha) preceded OT infusion or vice-versa. No significant difference (P>0.05) was seen in motility after PGF(2alpha) (423.33 +/- 31.12 mm(2)) infusion. The uterokinetic effect of OT was greatest when OT was administered i.v. (1696.50 +/- 195.46 mm(2)) followed by i.m. (819.82 +/- 39.96 mm(2)), and it was least effective when administered i.u. (607.83 +/- 21.56 mm(2)) as compared to control uterine motility (279.78 +/- 22.33 mm(2)). Skin electrical resistance values rose from 0 to 2000 ohms with PGF(2alpha) infusion (but not with OT), indicating that PGF(2alpha) was bioactive. It was concluded that PGF(2alpha) was not a uterokinetic substance in the cyclic mare.     

Rapid hydrophobic grid membrane filter-enzyme-labeled antibody procedure for identification and enumeration of Escherichia coli O157 in foods

An O-antigen-specific monoclonal antibody, labeled by horseradish peroxidase-protein A, was used in a hydrophobic grid membrane filter-enzyme-labeled antibody method for rapid detection of Escherichia coli O157 in foods. The method yielded presumptive identification within 24 h and recovered, on average, 95% of E. coli O157:H7 artificially inoculated into comminuted beef, veal, pork, chicken giblets, and chicken carcass washings. In food samples from two outbreaks involving E. coli O157:H7, the organism was isolated at levels of up to 10(3)/g. The lower limit of sensitivity was 10 E. coli O157 per g of meat. Specific typing for E. coli O157:H7 can be achieved through staining with labeled H7 antiserum or tube agglutination.     

Surface heterogeneity of bovine sperm revealed by aqueous two-phase partition

Ejaculated, bovine sperm have been subjected to multiple partition in aqueous two-phase systems. This partition, carried out in a countercurrent fashion, reveals heterogeneity of the sperm population with respect to surface properties. The sperm, when partitioned in phase systems that detect non-change associated surface properties (change-insensitive) are largely distributed as two distinct populations. In charge-sensitive phase systems (which principally detect cell surface molecules carrying charge) the sperm do not show any obvious surface heterogeneity. Considerable heterogeneity is revealed in affinity-ligand phase systems containing palmitic acid coupled to one of the phase components-poly(ethylene glycol). There is a difference in surface heterogeneity between sperm which have been washed in buffer or left unwashed, direct from the ejaculate. This is indicative of weak adsorption of proteins to the sperm surface in seminal fluid. These results show that bovine ejaculated sperm is a heterogeneous cell population having unequal distributions of a number of different surface molecules.     

Syngeneic monoclonal internal image anti-idiotopes as prophylactic vaccines

A syngeneic monoclonal anti-idiotope that behaves as an internal image of the mammalian reovirus type 3 cellular attachment protein (viral hemagglutinin) was used in the syngeneic host for the induction of a prophylactic anti-viral antibody response. These studies were performed without the aid of co-stimulation by viral antigens. The high stringency of this system enables us to define the maximum constraints on the use of anti-idiotopes as anti-viral vaccines. We have used the murine BALB/c monoclonal IgM anti-idiotope 87.92.6 to study the idiotope and antigen specificity, kinetics, dose dependence, adjuvant, carrier, and valency requirements of anti-idiotope-induced anti-viral antibody responses. These studies show that the production of high titer neutralizing antibody requires a lengthy (60 day) immunization protocol, which includes the use of adjuvant and multivalent anti-idiotope, and is dependent on anti-idiotope concentrations of greater than 50 micrograms. When administered in this manner anti-idiotope can stimulate serotype-specific antibody responses across species barriers at levels comparable with those obtained after inoculation with virus. The practical efficacy of these reagents and procedures is documented by the ability of maternal immunization with anti-idiotope to confer complete protection in neonates from a potentially lethal reovirus type 3 viral infection.     

Transposon donor plasmids, based on ColIb-P9, for use in Pseudomonas putida and a variety of other gram negative bacteria

Summary The properties of pLG221, a derivative of the ColIb plasmid carrying the transposon Tn5 are described. This plasmid can be used to introduce Tn5 by conjugation from Escherichia coli into a variety of Gram negative bacteria outside the host range for maintenance of ColIb. Plasmid pLG221, and a similar plasmid pLG223 carrying Tn10 may be of general utility as vectors for transposon-mediated mutagenesis in a variety of Gram negative bacteria.