An efficient in vitro shoot propagation of cranberry (Vaccinium macrocarpon ait.) by axillary bud proliferation

Summary Cultures of two eranberry (Vaccinium macrocarpon Ait.) cultivars, ‘Ben Lear’ and ‘Pilgrim’, and three eranberry clones from natural stands in Newfoundland were established in a nutrient medium containing N⁶[2-isopentenyl]adenine (2iP) from nodal and/or shoot-tip explants obtained under aseptic conditions. The cultivars differed in shoot regeneration in terms of shoot number per explant with various concentrations of 2iP over two culture periods. Best total shoot production was obtained when nodal segments were cultured in the medium supplemented with 2.5–5.0 mg 2iP l⁻¹ (12.3–24.6 μM). With higher 2iP levels, shoots did not expand and had a high mortality rate. Nodal explants of the three clones cultured in the same nutrient medium supplemented with 2.5 mg 2iP l⁻¹ (12.3 μM) produced three to five healthy axillary shoots per explant. In another experiment, nodal explants were more productive than shoot tips. In all experiments with subculture, there was an increase in shoot multiplication rate for all genotypes. Shoots were rooted in vitro in the same media used for shoot proliferation, but without any growth regulators. After their transfer to potting medium, almost all of the rooted plants survived. Cranberry genotypes can be efficiently propagated and maintained through nodal culture in a nutrient medium without auxin that contains 2.5–5 mg 2iP l⁻¹ (12–25 μM).     

An independent validation study of loci associated with nematode resistance in sheep

Gastrointestinal nematode infection is a constraint on sheep production worldwide. Selective breeding programmes to enhance resistance to nematode infection are currently being implemented in a number of countries. Identification of loci associated with resistance to infection or causative mutations for resistance would enable more effective selection. Loci associated with indicator traits for nematode resistance has been identified in previous studies. In this study, Scottish Blackface, Texel and Suffolk lambs were used to validate the effects at eight genomic regions previously associated with nematode resistance (OAR3, 4, 5, 7, 12, 13, 14, 21). No SNP was significantly associated with nematode resistance at the region‐wide level but seven SNPs in three of the regions (OAR4, 12, 14) were nominally associated with trichostrongyle egg count in this study and six of these were also significant when fitted as single SNP effects. Nematodirus egg count was nominally associated with SNPs on OAR3, 4, 7 and 12.     

Filamentous fungi of the Windmill Islands, continental Antarctica. Effect of water content in moss turves on fungal diversity

This study presents the effect of water content in moss turves from the Windmill Islands, Wilkes Land, continental Antarctica on the composition of associated filamentous fungi. The two most prevalent mosses were sampled: Grimmia antarctici and Bryum pseudotriquetrum. Results were expressed as dry weights. No relationship was found between water content of the mosses or the surrounding soil and fungal diversity. Ten species of fungi were recovered and all species belong to cosmopolitan taxa. Accepted: 21 June 1999     

Birth of a Western Lowland gorilla (Gorilla gorilla gorilla) following in vitro fertilization and embryo transfer

A 21-year-old multiparous female exhibiting 31–41 day menstrual cycles was given hFSH (225 IU/day, Metrodin 75, from cycle day 3 through 9 (menses = day 1) and hCG (10,000 IU, Profasi, on day 10 to stimulate follicular development. At 35 h after hCG, under isoflurane (AErrane) anesthesia, follicles were aspirated by controlled suction under transvaginal ultrasound guidance. Metaphase II oocyctes (n = 11) were placed in modified human tubal fluid (mHTF, 100 μl) medium under oil at 37°C in humidified 5% CO₂. Frozen semen, collected by voluntary ejaculation, was thawed (70°C H₂O bath, 6 sec), diluted slowly, centrifuged, and resuspended in mHTF, and 160,000 motile spermatozoa/ml were added at 6 h after oocyte recovery. At 21 h postinsemination (p.i.) eight oocytes were at the two-cell stage, five were cryopreserved, and three were cultured to the six- to eight-cell stage in mHTF with granulosa cells before transcervical uterine transfer at 47 h p.i. using a Teflon catheter. Micronized progesterone (400 mg/d) was orally administered for 10 weeks posttransfer (p.t.). Ultrasound examination revealed a single fetus at 15 weeks p.t., and unassisted delivery of a live 1.37 kg female infant occurred at 29 weeks. Am. J. Primatol. 41:247–260, 1997. © 1997 Wiley-Liss, Inc.     

Seasonal home range dynamics and sex differences in habitat use in a threatened,coastal marsh bird

A comprehensive understanding of spatiotemporal ecology is needed to develop conservation strategies for declining species. The king rail (Rallus elegans) is a secretive marsh bird whose range historically extended across the eastern United States. Inland migratory populations have been greatly reduced with most remaining populations inhabiting the coastal margins. Our objectives were to determine the migratory status of breeding king rails on the mid‐Atlantic coast and to characterize home range size, seasonal patterns of movement, and habitat use. Using radiotelemetry, we tracked individual king rails among seasons, and established that at least a segment of this breeding population is resident. Mean (±SE) home range size was 19.8 ± 5.0 ha (95% kernel density) or 2.5 ± 0.9 (50% kernel density). We detected seasonal variation and sex differences in home range size and habitat use. In the nonbreeding season, resident male home ranges coincided essentially with their breeding territories. Overwintering males were more likely than females to be found in natural emergent marsh with a greater area of open water. Females tended to have larger home ranges than males during the nonbreeding season. We report for the first time the use of wooded natural marsh by overwintering females. Brood‐rearing king rails led their young considerable distances away from their nests (average maximum distance: ~600 ± 200 m) and used both wooded natural and impounded marsh. King rails moved between natural marsh and managed impoundments during all life stages, but the proximity of these habitat types particularly benefitted brood‐rearing parents seeking foraging areas with shallower water in proximity to cover. Our results demonstrate the importance of interspersion of habitat types to support resident breeders. Summer draining of impounded wetlands that are seasonally flooded for wintering waterfowl allows regrowth of vegetation and provides additional habitat at a critical time for wading birds.     

Suppression of viral specific primary T-cell response following intense physical exercise in young but not old mice.

Intense exercise to exhaustion leads to increased susceptibility and severity of infections. T cells play an essential role in control of viral infections. Whereas immune suppression is considered as a likely mechanism for exhaustive exercise-induced susceptibility to infection, we know little about viral-specific T-cell response following exhaustive exercise in young or old mice. In this study, one group of female young (10-12 wk) and old (22-24 mo) C57BL/6 mice was exposed to a single bout of intense exercise to exhaustion and immediately infected with lymphocytic choriomeningitis virus (LCMV). Eight days later, at the peak of expansion phase of T-cell response, we used tetramers of MHC class I molecules containing viral peptides to directly visualize antigen-specific CD8 T cells and a sensitive functional assay measuring interferon-gamma production at the single-cell level to quantitate the CD8 and CD4 T-cell response. To evaluate the impact of intense exercise during both the initiation and evolution of the expansion phase of the T-cell response, a second group of young and old mice continued their daily bouts of intense exercise to exhaustion over the next 8 days. Our data show that, in young mice, LCMV infection following exhaustive exercise leads to suppression of LCMV-specific CD8 and CD4 T-cell responses, and this suppression effect occurs at the initiation of the expansion phase of viral-specific T cells. However, in old mice, unlike young mice, exhaustive exercise does not cause suppression of LCMV-specific T-cell responses.     

End-functionalized phosphorylcholine methacrylates and their use in protein conjugation

Polymer-protein conjugation was performed using N-hydroxysuccinimide and aldehyde-terminated zwitterionic polymers, and the resulting polymer-protein conjugates were characterized by gel electrophoresis and fast protein liquid chromatography. Methacryloyloxyethyl phosphorylcholine (MPC) polymers were prepared by atom transfer radical polymerization in which the requisite functional end-groups for protein conjugation were embedded within the polymerization initiators. These phosphorylcholine polymers were conjugated to lysozyme as a model protein, as well as two therapeutic proteins, granulocyte colony stimulating factor (G-CSF) and erythropoietin (EPO). These MPC polymer-protein conjugates represent alternatives to PEGylated proteins, with the potential to provide improved efficacy in a therapeutic treatment relative to the protein itself.     

Mutant Telomeric Repeats in Yeast Can Disrupt the Negative Regulation of Recombination-Mediated Telomere Maintenance and Create an Alternative Lengthening of Telomeres-Like Phenotype

Some human cancers maintain telomeres using alternative lengthening of telomeres (ALT), a process thought to be due to recombination. In Kluyveromyces lactis mutants lacking telomerase, recombinational telomere elongation (RTE) is induced at short telomeres but is suppressed once telomeres are moderately elongated by RTE. Recent work has shown that certain telomere capping defects can trigger a different type of RTE that results in much more extensive telomere elongation that is reminiscent of human ALT cells. In this study, we generated telomeres composed of either of two types of mutant telomeric repeats, Acc and SnaB, that each alter the binding site for the telomeric protein Rap1. We show here that arrays of both types of mutant repeats present basally on a telomere were defective in negatively regulating telomere length in the presence of telomerase. Similarly, when each type of mutant repeat was spread to all chromosome ends in cells lacking telomerase, they led to the formation of telomeres produced by RTE that were much longer than those seen in cells with only wild-type telomeric repeats. The Acc repeats produced the more severe defect in both types of telomere maintenance, consistent with their more severe Rap1 binding defect. Curiously, although telomerase deletion mutants with telomeres composed of Acc repeats invariably showed extreme telomere elongation, they often also initially showed persistent very short telomeres with few or no Acc repeats. We suggest that these result from futile cycles of recombinational elongation and truncation of the Acc repeats from the telomeres. The presence of extensive 3′ overhangs at mutant telomeres suggests that Rap1 may normally be involved in controlling 5′ end degradation.