Infectious Pancreatic Necrosis First Isolation of Virus from Fish in Norway

Infectious pancreatic necrosis (IPN) is a disease of salmonid fishes. It has been reported in many countries throughout the world (M’Gonigle 1940, Wood et al. 1955, Besse & Kinkelin 1965, Vestergård Jørgensen & Bregnballe 1969, Sano 1971, Ball et al 1971, Ljungberg & Vestergård Jørgensen 1972, Schlotfeldt et al. 1975). Outbreaks of the disease can cause serious losses in populations of hatchery reared salmonids, the mortality rate varying between 10 and 90 % (Vestergård Jørgensen & Kehlet 1971). There are at least four different serotypes of the virus distinguished by neutralization tests (Wolf et al. 1968). Twenty-five isolates of IPN virus in Denmark proved to represent only two serotypes (Sp and Ab) (Vestergård Jørgensen & Kehlet). The present paper reports the first isolation of IPN virus from the stock at a fish farm in Norway.     

A Field Outbreak Caused by Bovine Respiratory Syncytial Virus

Bovine respiratory syncytial virus (BRSV) caused a large epizootic of acute respiratory disease in Japan in 1968—69 (Inaba et al. 1970, Inaba et al. 1972). A much smaller outbreak occurred in Switzerland (Paccaud & Jacquier 1970). In Belgium the virus has been isolated from an outbreak of respiratory disease (Wellemans et al. 1970). BRSV has later been proved an important causal agent of respiratory disorders in the same country (Wellemans & Leiinen 1975). In England and USA the virus has caused and been isolated from outbreaks of acute respiratory disease in calves (Jacobs & Edington 1971, Rosenquist 1974, Smith et al. 1974). In Denmark BRSV has sporadically been isolated from pneumonic calf lungs (Bitsch et al. 1976).     

Chromosome differences in Peromyscus maniculatus populations at different altitudes in Colorado

Mice of the genus Peromyscus all have 48 chromosomes. Yet the appearance of the 48 chromosomes is highly variable from species to species (Hsu & Arrighi, 1966, 1968, 1971; Pathak et al., 1973) and even in different populations of the same species (Sparkes & Arakaki, 1966; Ohno et al., 1966; Hsu & Arrighi, 1968; Arakaki et al. 1970; Te & Dawson, 1971; Bradshaw & Hsu, 1972; Murray & Kitchin, 1976). The evolutionary significance of this variation and the mechanisms for its initiation and maintenance have been of interest for quite a few years. However, it was not until the sophisticated chromosome banding techniques became available that mammalian cytogeneticists were able to begin to study the chromosome variation of Peromyscus in some detail. The use of C-banding led Hsu & Arrighi (1971) to the finding that the short arms of chromosomes in three different species of Peromyscus contained constitutive heterochromatin. These results suggested that the variations in the number of acrocentric chromosomes in Peromyscus might be a result of different amounts of heterochromatin. Later studies (Duffey, 1972; Waterbury, 1972; and Pathak et al., 1973) were also consistent with this hypothesis.However, it was soon discovered that not all chromosomal differences among Peromyscus populations are due to heterochromatin changes. Studies by Arighi et al. (1976) and Murray & Kitchin (1976) showed that some chromosomal differences between species and subspecies of Peromyscus are due to pericentric inversions. Thus, it appears that both inversions and the addition of heterochromatin are involved in the evolution of the karyotype of Peromyscus.The purpose of our study was to investigate the chromosomes of Peromyscus maniculatus in different populations in Colorado (U.S.A.) and to test for relationships involving an altitudinal gradient. In the first part of this study, orcein stained chromosomes from three subspecies of mice sampled at nine different altitudes were examined for karyotype variability. In the second part of the study, karyotypes of two subspecies (P. m. rufinus and P. m. luteus), representing high and low altitude populations were examined with Q banding to determine the mechanisms responsible for chromosomal differences.     

Induction of Swine Dysentery with a Pure Culture of Treponema Hyodysenteriae in Vitamin E and Selenium Deficient Pigs

Several successful attempts have been made to induce swine dysentery in pigs using pure cultures of Treponema hyodysen-teriae (Taylor & Alexander 1971, Harris et al. 1972, Akkermans & Pomper 1973, Hughes et al. 1975). In these studies, either conventional or specific-pathogen-free pigs were used. In the present study, 2 approximately 8 weeks old conventional pigs (Nos. 1 and 2) were purchased and fed the same basic ration as used by Teige et al. (1977). In addition, 10 % cod liver oil was incorporated in the diet at each feeding. After a feeding period of 25 days rectal swabs were applied and examined for the presence of spirochaetes. The pigs were then fed a 3 days old primary and pure culture of T. hyodysenteriae on TSA-S400 medium (Songer et al. 1976). The culture originated from the colon of a pig with swine dysentery (Pig No. 4, Teige et al. 1977). Each pig received the agar contents of 5 petri dishes which were mixed with the food.     

Low dose insemination of mares using non-sorted and sex-sorted sperm.

Mares are generally inseminated with 500 million progressively motile fresh sperm and approximately 1 billion total sperms that have been cooled or frozen. Development of techniques for low dose insemination would allow one to increase the number of mares that could be bred, utilize stallions with poor semen quality, extend the use of frozen semen, breed mares with sexed semen and perhaps reduce the incidence of post-breeding endometritis. Three low dose insemination techniques that have been reported include: surgical oviductal insemination, deep uterine insemination and hysteroscopic insemination.Insemination techniques: McCue et al. [J. Reprod. Fert. 56 (Suppl.) (2000) 499] reported a 21% pregnancy rate for mares inseminated with 50,000 sperms into the fimbria of the oviduct.Two methods have been reported for deep uterine insemination. In the study of Buchanan et al. [Theriogenology 53 (2000) 1333], a flexible catheter was inserted into the uterine horn ipsilateral to the corpus luteum. The position of the catheter was verified by ultrasound. Insemination of 25 million or 5 million spermatozoa resulted in pregnancy rates of 53 and 35%, respectively. Rigby et al. [Proceedings of 3rd International Symposium on Stallion Reproduction (2001) 49] reported a pregnancy rate of 50% with deep uterine insemination. In their experiment, the flexible catheter was guided into position by rectal manipulation.More studies have reported the results of using hysteroscopic insemination. With this technique, a low number of spermatozoa are placed into or on the uterotubal junction. Manning et al. [Proc. Ann. Mtg. Soc. Theriogenol. (1998) 84] reported a 22% pregnancy rate when 1 million spermatozoa were inserted into the oviduct via the uterotubal junction. Vazquez et al. [Proc. Ann. Mtg. Soc. Theriogenol. (1998) 82] reported a 33% pregnancy rate when 3.8 million spermatozoa were placed on the uterotubal junction. Recently, Morris et al. [J. Reprod. Fert. 188 (2000) 95] utilized the hysteroscopic insemination technique to deposit various numbers of spermatozoa on the uterotubal junction. They reported pregnancy rates of 29, 64, 75 and 60% when 0.5, 1, 5 and 10 million spermatozoa, respectively, were placed on the uterotubal junction.Insemination of sex-sorted spermatozoa: One of the major reasons for low dose insemination is insemination of X- or Y-chromosome-bearing sperm. Through the use of flow cytometry, spermatozoa can be accurately separated into X- or Y-bearing chromosomes. Unfortunately, only 15 million sperms can be sorted per hour. At that rate, it would take several days to sort an insemination dose containing 800 million to 1 billion spermatozoa. Thus, low dose insemination is essential for utilization of sexed sperm. Lindsey [Hysteroscopic insemination with low numbers of fresh and cryopreserved flow-sorted stallion spermatozoa, M.S. Thesis, Colorado State University, Fort Collins, CO, USA, 2000] utilized either deep uterine insemination or hysteroscopic insemination to compare pregnancy rates of mares inseminated with sorted, fresh stallion sperm to those inseminated with non-sorted, fresh stallion sperm. Hysteroscopic insemination resulted in more pregnancies than ultrasound-guided deep uterine insemination. Pregnancy rate was similar for mares bred with either non-sorted or sex-sorted spermatozoa.In a subsequent study, Lindsey et al. [Proceedings of 5th International Symposium on Equine Embryo Transfer (2000) 13] determined if insemination of flow-sorted spermatozoa adversely affected pregnancy rates and whether freezing sex-sorted spermatozoa would result in pregnancies. Mares were assigned to one of four groups: group 1 was inseminated with 5 million non-sorted sperms using hysteroscopic insemination; group 2 was inseminated with 5 million sex-sorted sperms using hysteroscopic insemination; group 3 was inseminated with non-sorted, frozen-thawed sperm; and group 4 was inseminated with sex-sorted frozen sperm. Pregnancy rates were similar for mares inseminated with non-sorted fresh sperm, sex-sorted fresh sperm and non-sorted frozen sperm (40, 37.5 and 37.5%, respectively). Pregnancy rates were reduced dramatically for those inseminated with sex-sorted, frozen-thawed sperm (2 out of 15, 13%). These studies demonstrated that hysteroscopic insemination is a practical and useful technique for obtaining pregnancies with low numbers of fresh spermatozoa or low numbers of frozen-thawed spermatozoa. Further studies are needed to determine if this technique can be used to obtain pregnancies from stallions with poor semen quality. In addition, further studies are needed to develop techniques of freezing sex-sorted spermatozoa.     

A sequence of seventy-three nucleotides from the coliphage R17 genome

1. A sequence of 73 nucleotides of the RNA genome from coliphage R17 was determined. It can be read through in only one translational frame. The fragment is not part of the coatprotein cistron (Min Jou et al., 1972), nor does it come from the untranslated sequences described previously (Steitz, 1969; Nichols, 1970; Cory et al., 1970; de Wachter et al., 1971; Contreras et al., 1971; Cory et al., 1972). It contains two sequences of 23 and 24 nucleotides, 22 of which are identical. This kind of reiteration is the first one found in bacteriophage nucleic acid. 2. Improved conditions were found and tested for blocking oligonucleotides with carbodi-imide and cleaving by ribonuclease A at cytidylate residues. 3. A synthetic medium is described which allows labelling in vivo with (32)P to give specific radioactivities higher than those obtained in the procedures used previously.     

Fertility of Deep Frozen Boar Spermatozoa

In the present investigation the results of two insemination trials with deep frozen boar spermatozoa are presented. The aim of the trials was to study the effect of different thawing diluents and to compare the fertility of deep frozen spermatozoa from four boars. The trials utilized a total of 139 gilts. The thawing diluents used were boar seminal plasma, protein free seminal plasma, the thawing diluent OLEP and isotonic glucose solution. The composition of OLEP was based on physical and biochemical analyses of boar seminal plasma. The electrolyte levels, pH and osmotic pressure of OLEP are similar to those of boar seminal plasma. From the results it is evident that thawing in boar seminal plasma, protein free seminal plasma and OLEP yielded equal results. Thawing in isotonic glucose solution yielded significantly poorer results concerning percentage of fertilized ova 24–48 hrs. after insemination and almost significantly poorer fertility results four weeks after insemination. The possible effects of the thawing diluents are discussed. With the freezing procedure applied, electrolyte levels, pH and osmotic pressure seem to be factors of importance for the survival of the frozen and thawed spermatozoa and for the maintenance of their fertilizing capacity. Almost significant differences were found in fertility of spermatozoa from different boars. These differences were reflected in pregnancy rates as well as ratio of foetuses to c. 1. in pregnant gilts. The differences were found to be independent of thawing diluent. The variation seems to be caused by differences in resistance of the spermatozoa to the freezing and thawing procedure. The need for laboratory methods for selection of boars with spermatozoa of good freezability is stressed.     

Books

B atten , L. et al . 1973. Birdwatchers' year. Pp. 351, 18 black and white photographs, numerous text-figures. Berkhamsted
C lancey , P. A. 1971. A handlist of the birds of southern Moqambique
du P ont , J. E. 1971. Philippine birds
F arner , D. S. & K ing , J. R. (Eds) & P arkes , K. C. (Taxonomic editor). 1972
T inbergen , N. 1973. The animal in its world
W etmore , A. 1972. The birds of the Republic of Panami     

Freeze-resistant Trichinella (Trichinella nativa) Established on the Scandinavian Peninsula

Until the 1970’s, Trichinella spiralis (Owen 1835) was considered the only species within the genus Trichinella. Then T. pseudospiralis (Garkavi 1972) was classified as a separate species on the basis of morphological and biological features. The remaining morphologically homogenous “T. spiralis-group” has been split into 4 different species (or subspecies) on the basis of their biological and biochemical characteristics; T. nativa (Britov & Boev 1972), T. nelsoni (Britov & Boev 1972), T. spiralis sensu stricto and T. britovi (Pozio et al. 1992).     

Effect of intraventricular injection of 5,7-dihydroxytryptamine on regional tryptophan hydroxylase of rat brain

5,6-DIHYDROXYTRYPTAMINE has been shown to cause selective degeneration of serotonergic neurons in the central nervous sytem (BAUMGARTEN, LACHENMAYER and SCHLOSSBERGER, 1972b). This degeneration is accompanied by depletion of serotonin (BAUMGARTEN et al., 1971; 1972a) and loss of tryptophan hydroxylase activity (VICTOR, BAUMGARTEN and LOVENBERG, 1973) in certain regions of the brain. In the current experiments, the effect of 5,7-dihydroxytryptamine (another dihydroxylated tryptamine derivative) on tryptophan hydroxylase activity has been examined. Since tryptophan hydroxylase is the rate-limiting enzyme in serotonin biosynthesis and has a similar distribution to that of serotonin in the brain, it is used as a biochemical marker of serotonergic neurons, Recent experiments also indicate that 5,7-dihydroxytryptamine causes morphological damage to serotonergic neurons of the central nervous system (BAUMGARTEN and LACHENMAYER, 1972).     

Human molars from later Pleistocene deposits of Witkrans Cave,Gaap Escarpment,Kalahari Margin

Human molars from travertine deposits of Witkrans Cave (Gaap Escarpment, northern Cape Province, South Africa) are described. The Witkrans molars were discovered in direct association with later Pleistocene faunal remains and a sample of Middle Stone Age artifacts (Peabody, 1954; Clark, 1971; Sampson, 1974; Klein, 1984; Volman, 1984). The morphology and dimensions of the Witkrans molars resemble remains from other localities of similar age in southern Africa (Singer & Wymer, 1982; Grine & Klein, 1985; Grine et al., 1991; Rightmire & Deacon 1991) but exhibit differences from later Pleistocene occurrences in northern Africa (McBurney et al. 1953; Vallois & Roche, 1958; Ennouchi, 1969; Hublin & Tillier, 1981). These results offer further support for the existence of later Pleistocene human populations south of the Sahara which were distinct from contemporaneous peoples of Mediterranean Africa (Howell, 1978; Brauer, 1984; Rightmire, 1984; Klein 1992).     

The use of ejaculated boar semen after freezing in 2 or 6% glucerol for in vitro fertilization of porcine oocytes matured in vitro

Two concentrations of glycerol in a freezing diluent were tested with respect to the in vitro fertilizing capacity of frozen-thawed boar spermatozoa which, before exposure to oocytes, were subjected to 3 methods of fractionation. These were 1) the upper fraction, 2) the swim-up and 3) percoll gradinet-centrifugation. The highest proportions of motile spermatozoa were obtained by the swim-up procedure, while acrosomal integrity was best preserved by the upper fraction procedure. Raising the glycerol concentration from 2 to 6% (v/v) during freezing decreased the proportion of spermatozoa with a normal apical ridge. Spermatozoa separated by the upper fraction method showed the greatest penetration of oocytes and produced the highest indidence of polyspermy. The glycerol level affected penetration and polyspermy only with spermatozoa separated in a percoll gradient, where the higher level of glycerol increased oocytes penetration and polyspermy. Pronuclei formation was influenced by the separation procedure and by the glycerol concentration in the freezing diluent. The results indicate that frozen boar semen can be used for in vitro fertilization more successfully than fresh semen since penetration by frozen upper fraction spermatozoa was similar to, the degree of polyspermy was lower, and the formation of two pronuclei was greater (P<0.01) than in oocytes exposed to fresh semen.     

Genetics of subtilin and nisin biosyntheses

Several peptide antibiotics have been described as potent inhibitors of bacterial growth. With respect to their biosynthesis, they can be devided into two classes: (i) those that are synthesized by a non-ribosomal mechanism and (ii) those that are ribosomally synthesized. Subtilin and nisin belong to the ribosomally synthesized peptide antibiotics. They contain the rare amino acids dehydroalanine, dehydrobutyrine, meso-lanthionine, and 3-methyl-lanthionine. They are derived from prepeptides which are post-translationally modiffied and have been termed lantibiotics because of their characteristic lanthionine bridges (Schnell et al. 1988). Nisin is the most prominent lantibiotic and is used as a food preservative due to its high potency against certain gram-positive bacteria (Mattick & Hirsch 1944, 1947; Rayman & Hurst 1984). It is produced by Lactococcus lactis strains belonging to serological group N. The potent bactericidal activities of nisin and other lantibiotics are based on depolarization of energized bacterial cytoplasmic membranes. Breakdown of the membrane potential is initiated by the formation of pores through which molecules of low molecular weight are released. A trans-negative membrane potential of 50 to 100 mV is necessary for pore formation by nisin (Ruhr & Sahl 1985; Sahl et al. 1987). Nisin occurs as a partially amphiphilic molecule (Van de Ven et al. 1991). Apart from the detergent-like effect of nisin on cytoplasmic membranes, an inhibition of murein synthesis has also been discussed as the primary effect (Reisinger et al. 1980). In several countries nisin is used to prevent the growth of clostridia in cheese and canned food. The nisin peptide structure was first described by Gross & Morall (1971), and its structural gene was isolated in 1988 (Buchman et al. 1988; Kaletta & Entian 1989). Nisin has two natural variants, nisin A and nisin Z, which differ in a single amino acid residue at position 27 (histidin in nisin A is replaced by asparagin in nisin Z (Mulders et al. 1991; De Vos et al. 1993). Subtilin is produced by Bacillus subtilis ATCC 6633. Its chemical structure was first unravelled by Gross & Kiltz (1973) and its structural gene was isolated in 1988 (Banerjee & Hansen 1988). Subtilin shares strong similarities to nisin with an identical organization of the lanthionine ring structures (Fig. 1), and both lantibiotics possess similar antibiotic activities. Due to its easy genetic analysis B. subtilis became a very suitable model organism for the identification and characterization of genes and proteins involved in lantibiotic biosynthesis. The pathway by which nisin is produced is very similar to that of subtilin, and the proteins involved share significant homologies over the entire proteins (for review see also De Vos et al. 1995b). The respective genes have been identified adjacent to the structural genes, and are organized in operon-like structures (Fig. 2). These genes are responsible for post-translational modification, transport of the modified prepeptide, proteolytic cleavage, and immunity which prevents toxic effects on the producing bacterium. In addition to this, biosynthesis of subtilin and nisin is strongly regulated by a two-component regulatory system which consists of a histidin kinase and a response regulator protein.     

The Indirect Fluorescent Antibody Test (IFAT) for the Detection of Nosema Cuniculi Antibodies in the Blue Fox (Alopex Lagopus)

During recent years nosematosis has been a major problem in the breeding of blue fox in the Scandinavian countries, causing heavy losses among growing pups (Nordstoga 1972, Nordstoga et al. 1974). The lack of reliable methods for diagnosing the infection in live foxes has so far made epizootiologic studies of the disease very difficult. However, reports on the IFAT in rabbits with nosematosis (Cox et al. 1972, Chalupsky et al. 1971, 1973, 1974), encouraged the search for a method of detecting Nosema antibodies in fox sera.     

The effect of oviductal fluid on protein tyrosine phosphorylation in cryopreserved boar spermatozoa differs with the freezing method

Sperm capacitation takes place in the oviduct and protein tyrosine phosphorylation of sperm proteins is a crucial step in capacitation and acquisition of fertilizing potential. Cryopreserved spermatozoa show altered expression of protein tyrosine phosphorylation in the oviduct. The present study compared two freezing methods (conventional-conventional freezing (CF) and simplified-simplified freezing (SF) methods) for their effect on the ability of boar spermatozoa to undergo protein tyrosine phosphorylation in response to oviductal fluid (ODF). Cryopreserved boar-spermatozoa were incubated with pre- and post-ovulatory ODF for 6 h at 38 °C under 5% CO₂. Aliquots of sperm samples were taken at hourly intervals and analyzed for kinematics and protein tyrosine phosphorylation. Global protein tyrosine phosphorylation in spermatozoa was measured using flow cytometry and different patterns of phosphorylation were assessed using confocal microscopy. Immediately after thawing, no significant difference was observed in post-thaw sperm motility, velocity and global tyrosine phosphorylation between the two methods of freezing although the freezing method significantly (P < 0.05) influenced the effect of oviductal fluid on these parameters during incubation. While spermatozoa frozen by the CF method showed a significantly higher (P < 0.001) proportion of phosphorylation in response to preovulatory ODF during incubation, spermatozoa frozen by the SF method did not elicit such significant response as there was no significant difference in the proportion of tyrosine phosphorylated spermatozoa between treatments at any given time during incubation. If the CF method was used, the proportion of spermatozoa displaying either tail or full sperm phosphorylation increased in response to both preovulatory (EODF) and postovulatory oviductal fluid. However, if the SF method was used, a significant increase in these patterns was noticed only in the EODF treated group. The present study demonstrates that preovulatory isthmic ODF induce tyrosine phosphorylation in a higher proportion of boar spermatozoa compared to the post-ovulatory fluid and that the method of freezing significantly influences the response of post-thaw spermatozoa to porcine ODF.     

Cryopreservation-induced alterations in protein tyrosine phosphorylation of spermatozoa from different portions of the boar ejaculate

Previous studies have shown that boar sperm quality after cryopreservation differs depending on the ejaculate fraction used and that spermatozoa contained in the first 10 mL (P1) of the sperm-rich fraction (SRF) show better cryosurvival than those in the SRF-P1. Since protein tyrosine phosphorylation (PTP) in spermatozoa is related with the tolerance of spermatozoa to frozen storage and cryocapacitation, we assessed the dynamics of cryopreservation-induced PTP and intracellular calcium ([Ca²⁺]i) in spermatozoa, using flow cytometry, from P1 and SRF-P1 of the boar ejaculate at different stages of cryopreservation. Sperm kinetics, assessed using a computer-assisted semen analyzer, did not differ between P1 and SRF-P1 during cryopreservation but the decrease in sperm velocity during cryopreservation was significant (P < 0.05) in SRF-P1 compared to P1. There were no significant differences in percentages of spermatozoa with high [Ca²⁺]i between P1 and SRF-P1 in fresh as well as in frozen–thawed semen. A higher (P < 0.001) proportion of spermatozoa displayed PTP during the course of cryopreservation indicating a definite effect of the cryopreservation process on sperm PTP. The proportion of spermatozoa with PTP did not differ significantly between portions of the boar ejaculate. However at any given step during cryopreservation the percentage of spermatozoa with PTP was comparatively higher in SRF-P1 than P1. A 32 kDa tyrosine phosphorylated protein, associated with capacitation, appeared after cooling suggesting that cooling induces capacitation-like changes in boar spermatozoa. In conclusion, the study has shown that the cryopreservation process induced PTP in spermatozoa and their proportions were similar between portions of SRF.     

Cryopreservation of Iberian pig spermatozoa. Comparison of different freezing extenders based on post-thaw sperm quality

The aim of this study was to evaluate the cryoprotective effect of different freezing extenders against cryopreservation injuries on Iberian boar sperm. The sperm-rich fraction was collected and pooled from six sexually mature Iberian boars, and was frozen in different extenders containing glucose, lactose or fructose as sugar source and including Orvus ES Paste only in the freezing extender-2 (Glucose; Lactose and Fructose) or in both freezing extenders (Glucose2; Lactose2 and Fructose2). During the cryopreservation process, the supernatant was removed after the centrifugation step, then was extended with freezing extender-1 for the equilibration period and with freezing extender-2 immediately before freezing. Post-thaw sperm characteristics, such as plasma membrane integrity (SYBR-14/PI), mitochondrial function (Rhodamine 123) and acrosome integrity (NAR), were monitored. Overall sperm motility and the individual kinematic parameters of motile spermatozoa (assessed by the computer-aided sperm analysis system Sperm Class Analyzer [SCA]) were recorded in the different experimental treatments. Measurements were taken at 30 and 150 min post-thaw. The state of the acrosome after thawing did not show significant differences between the freezing extenders studied. Freezing–thawing caused a significant decrease (P < 0.001) in plasma membrane integrity and in mitochondrial activity in the spermatozoa frozen with Orvus ES Paste in both freezing extenders. Furthermore, spermatozoa frozen with Orvus ES Paste in both freezing extenders exhibited lower (P < 0.05) motility and kinematic parameters than those frozen in the absence of Orvus ES Paste in the first freezing extender. The spermatozoa frozen with the Lactose extender and with Orvus ES Paste only in the second freezing extender showed a better evolution of the motility and kinematic characteristics (P < 0.05) over time. The deterioration in post-thaw sperm motility and kinematic parameters were concurrent with reduced sperm characteristics. It can be suggested that in the Iberian pig, the beneficial effects of Orvus ES Paste during the freezing process of spermatozoa is time dependent. The analysis of different sperm characteristics such as motility, plasma membrane integrity and mitochondrial function, determined that the extenders studied in the present experiment affected the quality of frozen-thawed semen in Iberian boar.     

Giemsa banding patterns in chronic lymphocytic leukaemia.

The banding patterns of chromosomes from 20 patients with chronic lymphocytic leukaemia (C.L.L.) have been analyzed. 97 of 100 metaphases examined had a normal banding pattern. The 3 remaining metaphases, all from one patient had bands similar to those seen after aging. It is concluded that the chromosomes in C.L.L. have normal banding patterns. The majority of cytogenetic studies in chronic lymphocytic leukaemia have reported normal chromosomes (Fitzgerald and Adams 1965; Oppenheim et al., 1965; Lawler et al., 1968). An inherited abnormality of G group chromosome (No. 22) has been reported in a family, three members of whom developed C.L.L. (Fitzgerald and Hamer, 1969), but further investigations of cases of familial leukaemia failed to reveal a similar abnormality (Fitzgerald et. al., 1966). The development of new techniques which allow the positive identification of individual chromosomes (Caspersson et al., 1969; Dutrillaux and Lejeune, 1971; Sumner et al., 1971; Seabright, 1971), has revolutionised human cutogenetics and revealed additional information regarding chromosome abnormalities and leukaemia (Rowley, 1973; Lobb et al., 1972; Milligan and Garson, 1974). The purpose of this investigation was to determine whether the chromosomes in C.L.L. have normal banding patterns.     

Cryo-scanning electron microscopy (Cryo-SEM) of boar semen frozen in medium-straws and MiniFlatPacks

In this study we demonstrate, in the frozen state, the architecture of frozen boar spermatozoa collected from the sperm-rich fraction of ejaculates (n=13) from four fertile boars packed and split-frozen in medium-straws (MS) and MiniFlatPacks (MFP), cross-sectioned in the frozen state and evaluated by image analysis on images obtained by use of cryo-scanning electron microscopy (Cryo-SEM). The tested hypothesis was that the degree of in situ dehydration and levels of homogeneity of boar semen either frozen in MSs or MFPs packages differ between them, with MFPs allowing for a more uniform dehydration of the spermatozoa and a higher cryosurvival, monitored by computer assisted sperm analysis (CASA) as proportion of linearly motile spermatozoa, compared to semen packaged and processed in MSs. The organization and relative surface of biological material (veins; e.g., frozen extender, bound water, solutes and spermatozoa) as well as free water (lakes) was measured as the degree of dehydration of the samples. The apparent organization of lakes and veins differed between packages, with the MFPs depicting larger lakes than the MSs. The sizes of the lakes in the latter appeared, moreover, highly asymmetrical depending on their position of the section. The relative surface of these lakes per section, respectively veins differed between packages (P<0.05), indicating a larger amount of free-water (lakes; 81.73+/-2.07% vs. 77.91+/-1.57%) in the MFPs and, consequently, thinner veins than in MSs. In conclusion, MFPs seem to allow for a more homogenous dehydration of the spermatozoa/frozen extender compared to MSs, which might account for their somewhat better sperm quality post-thaw.     

Microtubules with 15 subunits in cockroach epidermal cells

Since Ledbetter and Porter (1964) described the 13 subunits which are visible in cross sections of negatively stained plant microtubules, subsequent observations have generally confirmed this number. By using Mizuhira's fixative composed of tannic acid and glutaraldehyde, it is easyto demonstrate the subunits of microtublules without optical reinforcement Cytoplasmic microtubules and sperm axonemes, fixed with Mizuhira's fixtive, similarly show 13 subunits (Mizuhira's and Futaesaku, 1971, 1972; Futaesaky et al., 1972; Tilney et al., 1973). This paper will describe a particular type of microtubule in insect epidermal cells fixed with the above fixative. The number of the subunits is found to be 15 in tranverse sections.