Sperm capacitation in vitro in the eld's deer

Sperm capacitation was examined in the endangered Eld's deer (Cervus eldi thamin). Sperm motility and viability (percentage of sperm cells with intact membranes) were assessed in vitro over time after attempting to induce capacitation in TALP alone and TALP supplemented with calcium (10 mM CaCl2), dibutyryl cAMP (1 mM dbcAMP), or fetal calf serum (20% FCS). Sperm aliquots were evaluated at 0, 3, 6, 9, and 12 h for motility, viability, and ability to acrosome react after exposure to calcium ionophore (A23187, CI; 10 microM) or lysophosphatidylcholine (LC; 100 microg/mL). Fresh sperm aliquots in TALP + 10 mM CaCl2 exposed to CI had fewer (P < 0.05) intact acrosomes than the TALP control (TALP alone) or dbcAMP and FCS treatments after 9 h. Mean (+/- SEM) percentage of intact acrosomes of spermatozoa incubated in medium with increased CaCl2 declined (P < 0.05) from 80.2 +/- 2.6% (0 h) to 49.7 +/- 7.3% after prolonged incubation (9 h). The proportion of capacitated fresh spermatozoa was not influenced by LC treatment. Capacitation was not induced (P > 0.05) by any of the presumptive sperm capacitators after freeze-thawing. Likewise, neither CI nor LC induced the acrosome reaction (AR) in these spermatozoa, suggesting that the freeze-thawing process may have caused membrane damage. Results revealed that the supplementation of medium with CaCl2 evokes capacitation in some spermatozoa. However, Eld's deer spermatozoa appear remarkably resistant to conventional stimulators of capacitation and the AR.     

Creatine phosphokinase in domestic cat epididymal spermatozoa

Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cytoplasm and increased creatine phosphokinase (CK) content. This study determined: (1) if CK could be detected by immunostaining cat spermatozoa from the caput, corpus, and cauda epididymis, (2) fluctuations in the proportions of spermatozoa with mature or immature CK-staining patterns during epididymal sperm transit, and (3) how well sperm maturity (as determined by a CK marker) correlated with testicular or epididymal dysfunctions associated with morphological sperm abnormalities. One epididymis was collected from each of 37 cats after orchiectomy and processed immediately to allow sperm morphology evaluations on a 'regional' basis. Sperm released from the contralateral epididymis were evaluated for motility, sperm membrane integrity, and immunostaining with CK-B antibodies. Proportions of spermatozoa with malformed or detached heads, proximal droplets and acrosomal or midpiece abnormalities decreased (P < 0.05) from the caput to the cauda epididymis. In contrast, proportions of spermatozoa that were motile, membrane-intact or with flagellar abnormalities or distal droplets increased (P < 0.05) from the caput to cauda region. Percentages of spermatozoa with an immature CK-staining pattern also decreased (P < 0.05) with epididymal transit (which differs from that reported for the human and stallion). There was no correlation (P > 0.05) between sperm morphology and the CK-staining patterns. In summary, the results reveal that some specific sperm malformations in the domestic cat are of testicular origin, whereas others develop during epididymal transit.     

The role of the rock cod Notothenia coriiceps Richardson, 1844 in the life-cycle of Antarctic parasites

Fifty specimens of Notothenia coriiceps caught in Potter Cove, King George Island, were examined for ecto- and endoparasites. Of the 22 parasite species found, 18 were helminths, 2 were hirudineans and 2 were crustaceans. The isopod Aega antarctica and an unidentified hirudinean are reported for the first time from this fish host. Dominant parasites were the adults of Aspersentis megarhynchus, the invasive stage of Corynosoma spp. (cystacanth) and the adults of Macvicaria pennelli, with respective prevalences of infestation of 94, 76 and 74%. The preferred sites of infestation were the pylorus and intestine, where five different larval (nematodes and cestodes) and eight adult (digeneans and acanthocephalans) parasite species were found. No adult nematodes and cestodes were found and no parasites could be isolated from the musculature. The results of the present study are related to previous findings on the parasite fauna of N. coriiceps. The comparison implies a high parasite diversity in this benthic Antarctic fish species. Most parasites found appear to have a wide range of distribution within Antarctic waters together with a low host specificity. Besides its role as final host for several species of trematodes and acanthocephalans, N. coriiceps serves as transmitter of parasite larvae to piscivorous birds and seals. It is concluded that the parasite fauna in Antarctic fish species provides important insights into the different habitat use and trophic relationship of their fish hosts. Received: 11 September 1997 / Accepted: 12 January 1998     

The Drosophila neural lineages: a model system to study brain development and circuitry

In Drosophila, neurons of the central nervous system are grouped into units called lineages. Each lineage contains cells derived from a single neuroblast. Due to its clonal nature, the Drosophila brain is a valuable model system to study neuron development and circuit formation. To better understand the mechanisms underlying brain development, genetic manipulation tools can be utilized within lineages to visualize, knock down, or over-express proteins. Here, we will introduce the formation and development of lineages, discuss how one can utilize this model system, offer a comprehensive list of known lineages and their respective markers, and then briefly review studies that have utilized Drosophila neural lineages with a look at how this model system can benefit future endeavors.     

Solvent isotope effects in intramolecular catalysis: Acyl transfer reactions of 4-nitrophenyl 5-nitrosalicylate in aqueous tris buffer

A kinetic study of the reactions of 4-nitrophenyl 5-nitrosalicylate in aqueous Tris buffer at 25°C has revealed three kinetically significant reactions: Tris aminolysis of the un-ionized substrate, Tris aminolysis of the ionized substrate, and spontaneous hydrolysis of the ionized substrate. Solvent isotope effects have been measured for all three reactions. Mechanisms are discussed, and the conclusion is reached that intramolecular catalysis is operating in only the spontaneous hydrolysis.     

E1A-CR3 interaction-dependent and -independent functions of mSur2 in viral replication of early region 1A mutants of mouse adenovirus type 1

mSur2, a subunit of the Mediator complex, is required for efficient mouse adenovirus type 1 (MAV-1) replication (L. Fang, J. L. Stevens, A. J. Berk, and K. R. Spindler, J. Virol. 78:12888-12900, 2004). We examined the contributions of early-region 1A (E1A) to mSur2 function in MAV-1 replication with E1A mutant viruses. At a multiplicity of infection (MOI) of 1, viruses containing CR3 replicated better in Sur2+/+ mouse embryonic fibroblasts (MEFs) than in Sur2-/- MEFs. In contrast, viruses lacking CR3 replicated no better in Sur2+/+ than in Sur2-/- MEFs. This result supports the hypothesis that the E1A CR3-mSur2 interaction is important for MAV-1 replication. However, at an MOI of 0.05, viruses lacking CR3 showed replication defects in Sur2-/- MEFs compared to Sur2+/+ MEFs, suggesting an E1A CR3 interaction-independent function of mSur2 in MAV-1 replication in cell culture. Paradoxically, CR1Delta, CR2Delta, and CR3Delta mutant viruses replicated slightly more efficiently than wild-type (wt) MAV-1 and E1A null mutant viruses in Sur2-/- MEFs at an MOI of 0.05. Coinfection of Sur2-/- MEFs with wt MAV-1 and CR1Delta, CR2Delta, or CR3Delta mutant viruses rescued the defects of wt MAV-1 replication. This result suggests that an inhibiting effect on wt E1A protein expression and/or E1A function might account for the severe viral replication defect of MAV-1 in Sur2-/- MEFs at an MOI of 0.05. Moreover, titrations of virus yields from infected brains of inbred strains of mice showed that E1A null and CR3Delta mutant viruses had a significant defect in virus replication compared to wt MAV-1. This result supports the hypothesis that the MAV-1 E1A-mSur2 interaction is important in MAV-1 replication in mice.