Partitioning of reproduction in animal societies

A key feature differentiating cooperative animal societies Is the apportionment of reproduction among individuals. Only recently have studies started to focus on intraspecific variability in the distribution of reproduction within animal societies, and the available data suggest that this variability might be greater than previously suspected. How can one account for intra-and interspecific variability in partitioning of reproduction? This Is one of the most intriguing problems in the study of social behaviour, and understanding the factors underlying this variability is one of the keys to understanding the properties of complex animal societies.     

Identification and localization of molecular markers linked to the Lr9 leaf rust resistance gene of wheat

Near-isogenic lines (NILs) for the leaf rust resistance gene Lr9 were screened for polymorphisms at the molecular level. RAPD (random amplified polymorphic DNA) primers as well as RFLP (restriction fragment length polymorphism) markers were used. Out of 395 RAPD primers tested, three showed polymorphisms between NILs, i.e., an additional band was found in resistant lines. One of these polymorphic bands was cloned and sequenced. Specific primers were synthesized, and after amplification only resistant lines showed an amplified product. Thus, these primers define a sequence-tagged site that is specific for the translocated fragment carrying the Lr9 gene. A cross between a resistant NIL and the spelt (Triticum spelta) variety Oberkulmer was made, and F₂ plants were analyzed for genetic linkage. All three polymorphisms detected by the PCR (polymerase chain reaction) and one RFLP marker (cMWG684) showed complete linkage to the Lr9 gene in 156 and 133 plants analyzed, respectively. A second RFLP marker (PSR546) was closely linked (8±2.4 cM) to the Lr9 gene and the other four DNA markers. As this marker maps to the distal part of the long arm of chromosome 6B of wheat, Lr9 and the other DNA markers also map to the distal region of 6BL. All three PCR markers detected the Lr9 gene in independently derived breeding lines and varieties, thus proving their general applicability in wheat breeding programs.     

Successful in vitro and in vivo development of in vitro fertilized two- to four-cell cat embryos following cryopreservation, culture and transfer

In vitro and in vivo survival of in vitro-derived 2- to 4-cell cat embryos following cryopreservation was examined. Prefreeze 1- vs 2-step cryoprotectant exposure (Experiment 1) and warming method (Experiment 2) on zona pellucida damage and development in vitro were compared. To determine viability in vivo, frozen/thawed embryos were cultured in vitro to the morula/early blastocyst stage and transferred to synchronous recipients (Experiment 3). At 24 to 26 h after IVF, embryos were cryopreserved in 1.4 M propanediol (Pr) + 0.125 M sucrose (Su) by cooling at 0.3 degrees C/min from -6 degrees C to -30 degrees C and storing in liquid nitrogen. Autologous embryos were cultured in vitro for 7 d. After warming for 5 sec in air and 10 sec at 37 degrees C in water (Experiments 1 to 3), or at room temperature air (22 degrees C; Experiment 2), the cryoprotectant was removed and embryos were cultured in vitro for 6 d (Experiments 1 and 2). Development was assessed after staining by counting cell numbers/embryo and determining the percentages at the 2- to 4-cell (nonsurvivor), pre (5 to 15), early (16 to 32), mid (33 to 50), late (>50) morula or blastocyst stages. Post-thaw development to late morula/blastocyst after 1-step exposure (68%, 15 min Pr + Su) was higher (P< 0.05) than that after 2-step exposure (36%, 15 min Pr and 15 min Pr + Su). Both warming methods produced similar percentages of embryos with damaged zonae (13 to 15%) and equivalent development to morula/blastocyst (64 to 69%). Development in vitro to early morula/blastocyst of frozen embryos with intact zonae was similar to that of nonfrozen embryos. Following cryopreservation, most 2- to 4-cell cat embryos retained their capability for in vitro development to morula/blastocyst, and in vivo viability was demonstrated by the birth of 3 live kittens to 2 of 4 recipients following the transfer of 58 embryos.     

Molecular map of Chromosome 19 including three genes affecting bleeding time: ep,ru, and bm

The mouse ruby eye (ru) and pale ear (ep) pigment dilution genes cause platelet storage pool deficiency (SPD) and prolonged bleeding times. The brachymorphic (bm) gene, in addition to causing skeletal abnormalities, is also associated with prolonged bleeding times. All three hemorrhagic genes are found within 10 cM on Chromosome (Chr) 19. In this study, 15 microsatellite markers and five cDNAs, spanning 21 cM of Chr 19, were mapped in relation to the bm, ep, and ru genes in 457 progeny of an interspecific backcross utilizing the highly inbred strain PWK derived from the Mus musculus musculus species. Several markers were found to be closely linked to the three genes and should be useful as entry points in their eventual molecular identification.     

Nitrate limitation of N2O production and denitrification from tropical pasture and rain forest soils

Nitrous oxide production was measured in intact cores taken from active pasture and old-growth forest Inceptisols in the Atlantic Lowlands of Costa Rica. Following additions of aqueous KNO₃ or glucose, or the two combined amendments, the cores were incubated in the laboratory to determine if N₂O production rates were either N-limited or C-limited in the two land use types. Differences in rates of denitrification (N2₂O + N₂ production) among amended forest and pasture soils were determined by addition of 10% C₂H₂.The forest soils were relatively insensitive to all amendment additions, including the acetylene block. Forest N₂O production rates among the treatments did not differ from the controls, and were consistently lower than those of the pasture soils. With the addition of glucose plus nitrate to the forest soils, production of N₂O was three times greater than the controls, although this increase was not statistically significant. On the other hand, the pasture soils were definitely nitrogen-limited since N₂O production rates were increased substantially beyond controls by all the amendments which contained nitrate, despite the very low N level (5 mg N kg^–1 soil) relative to typical fertilizer applications. With respect to the nitrate plus glucose plus acetylene treatment, denitrification was high in the pasture soils; N₂O production in the presence of C₂H₂ was 150% of the rate of N₂O production measured in the absence of the acetylene block. The results are discussed in relation to the effects of agricultural land use practices and subsequent impacts of disturbance on N₂O release.     

Regulation of circulating levels of the crustacean hyperglycemic hormone: evidence for a dual feedback control system

The effects of glutamate, aspartate, glycine, proline, alanine, taurine, glycerol, glucose and lactate injections on the haemolymph levels of the crustancean hyperglycemic hormone and/or glucose and lactate in the shore crab, Carcinus maenas, were investigated. Only glucose and lactate caused significant changes of hyperglycaemic hormone levels. Glucose injections resulted in a drop of both hormone and lactate, while lactate had an opposite effect, i.e. it raised both crustacean hormone and glucose levels. The results suggest that during increases in glycolytic flux, lactate may cause a release of hormone by a positive feedback mechanism. The hormone would then stimulate glycogenolysis, thus increasing glucose availability. If more glucose is released than is metabolized, excess glucose may leak from the cells and suppress crustancean hyperglycemic hormone release from the X-organ/sinus gland complex by negative feedback.Abbreviations ABTS 2,2-azino-bis (3-ethylbenzthiazoline sulphonic acid) - ANOVA one-way analysis of variance - BSA bovine serum albumin - BW body weight - CHH crustacean hyperglycemic hormone - ELISA cnzyme-liked immunosorbent assay - GIH gonadinhibiting hormone - IgG immunoglobin G - MIH moult-inhibiting hormone - MTGXO medulla terminalis X-organ - PB sodium phosphate buffer - PBS phosphate buffered saline - Pi inorganic phosphate - XO-SG X-organ-sinus gland complex     

HLA-DP/DR interaction in early onset pauciarticular juvenile chronic arthritis

We investigated the polymorphic second exon of the HLA-DPB1 and HLA-DRB1 genes, using in vitro DNA amplification by polymerase chain reaction (PCR) and oligonucleotide hybridization in 136 patients with early onset pauciarticular juvenile chronic arthritis (EOPA-JCA) and 199 healthy controls. The analysis of the HLA-DRB1 system revealed that most of the DRB1 alleles are not indifferent with respect to susceptibility to EOPA-JCA. There is a hierarchy of susceptible (DRB1*08, DR5), permissive (DRB1*01), moderately protective (DR2, DRB1*04), and protective (DRB1*07) alleles. In contrast, no hierarchy could be shown for the HLA-DPB1 system. DPB1*0201 was found to be susceptible. The relatively frequent alleles DPB1*0402 and DPB1*0401 seem to be indifferent. The associations with DPB1*0201, DR5, and DRB1*08 are independent of each other: that is to say they, are not brought about by linkage disequilibrium. The susceptible alleles DPB1*0201 and DR5 show evidence for interaction in the pathogenesis of EOPA-JCA. Interaction seems likely between DPB1*0201 and DRB1*08, DR5 and DRB1*08, or between DR6 and DRB1*08. The strongest interaction exists between DPB1*0201 and a common DQ factor associated with both DR5 and DRB1*08. Finally, we observed a hierarchy among the various marker combinations, where the risk of developing EOPA-JCA increases with the number of associated markers present in an individual.This work was supported by SFB217.The data presented here are part of the doctoral thesis of C. Paul.     

Polymorphism of the tumor necrosis factor beta gene in systemic lupus erythematosus: TNFB-MHC haplotypes

We investigated the Nco I restriction fragment length polymorphism (RFLP) of the tumor necrosis factor beta (TNFB) gene in 173 patients with systemic lupus erythematosus (SLE), 192 unrelated healthy controls, and eleven panel families, all of German origin. The phenotype frequency of the TNFB*1 allele was significantly increased in patients compared to controls (63.6% vs 47.1%, RR = 1.96, p <0.002). The results of a two-point haplotype statistical analysis between TNFB and HLA alleles show that there is linkage disequilibrium between TNFB*1 and HLA-A1, Cw7, B8, DR3, DQ2, and C4A DE. The frequency of TNFB*1 was compared in SLE patients and controls in the presence or absence of each of these alleles. TNFB*1 is increased in patients over controls only in the presence of the mentioned alleles. Therefore, the whole haplotype A1, Cw7, B8, TNFB*1, C4A DE, DR3, DQ2 is increased in patients and it cannot be determined which of the genes carried by this haplotype is responsible for the susceptibility to SLE. In addition, two-locus associations were analyzed in 192 unrelated healthy controls for TNFB and class I alleles typed by serology, and for TNFB and class II alleles typed by polymerase chain reaction/oligonucleotide probes. We found positive linkage disequilibrium between TNFB*1 and the following alleles: HLA-A24, HLA-B8, DRB1*0301, DRB1*1104, DRB1*1302, DQA1*0501, DQB1*0201, DQB1*0604, and DPB1*0101. TNFB*2 is associated with HLA-B7, DRB1*1501, and DQB1*0602.This study was supported by grants from the Federal Ministry of Research and Technology (BMFT/DFVLR, 01 VM 8608/9), the German Academic Exchange Service (DAAD, 322/501/014/0), and SFB (217).This work is part of the doctoral thesis of M. P. Bettinotti.