Linkage analyses of human peptidase C (PEPC), human factor H (HF), and coagulation factor XIIIB (F13B)

Summary Linkage data on human peptidase C (PEPC), human factor H (HF), and coagulation factor XIIIB (F13B) are presented. The results confirm linkage between HF and F13B (lod=5.32 at =0.10 in males), and give strong evidence for linkage between PEPC and HF (lod=5.14 at =0.10 in males) and between PEPC and F13B (lod=3.55 at =0.10 in males). The claim that PEPA is linked with HF must be withdrawn.     

Macrophage-activating factor extracted from mycoplasmas

Summary Mycoplasmas (M. gallisepticum, chicken mycoplasmas), in concert with interferon (IFN), were effective in activating macrophages (M) to be tumoricidal. The M-activating capacity of mycoplasmas was maintained after treatment with heat, 0.1 M NaOH, 1 M HC1, or trypsin. M-activating factor was extracted from mycoplasmas with chloroform/methanol and water (Mf-B). Mf-B was also effective in activating M in the presence of IFN. The threshold dose of Mf-B for M of ordinary C3H/He mice and that for those of C3H/HeJ mice, the latter being known to be low responders to bacterial lipopolysaccharide, were actually the same. This seems to indicate that the effectiveness of Mf-B was not attributable to possibly contaminating lipopolysaccharides, and that the pathway of activity of Mf-B is different from that of lipopolysaccharides. Since the M-activating principle was only a very small part of Mf-B, we have not yet succeeded in identifying it, but there was no evidence that it was protein, nucleic acid, sugar, or lipid. The cytotoxicity of M activated by Mf-B plus IFN was dependent onl-arginine in the culture, suggesting that arginine metabolites are involved in M cytotoxicity. Mf-B induced a small amount of tumor necrosis factor in M, and this induction was markedly enhanced by IFN.     

Exclusion of two candidate pigment loci,c and b,part of chromosome 11p,and 33 random polymorphic markers as the locus for tyrosinase-positive oculocutaneous albinism

The locus for Tyrosinase-Positive Oculocutaneous Albinism (ty-pos OCA) has not yet been localised. The search for the ty-pos OCA locus has included a search for linkage to candidate pigment loci and a candidate chromosomal region, as well as a random search using highly polymorphic markers in 42 families, including 271 individuals of whom 79 are affected. The lod scores for the tyrosinase (TYR) locus (11q14–q21), homologous to the albino locus, c, in the mouse and the CAS2/TRP1 locus (9p22-pter), homologous to the brown locus, b, in the mouse were -5.89 and -7.22, respectively, at a recombination fraction of =0.01, thus excluding them from being the ty-pos OCA locus. In the candidate chromosomal region, 11p, four loci (probes) were tested, SAA (pSAA82), CALC (pHC36), HBB (Gamma-globin haplotype) and an AC repeat polymorphism at the Wilm's Tumour locus (WT1). A portion of 11p was excluded with the following lod scores: pSAA82 lod=-2.05 at =0.10; pHC36 lod=-3.87 at =0.05; gamma-globin haplotype lod=-2.80 at =0.10; and WT1 lod=-2.34 at =0.10. Thirty-three polymorphic markers randomly distributed on 13 different chromosomes were all excluded from close linkage to ty-pos OCA.     

Assortative mating and the genetic correlation

Summary The effect of assortative mating on the genetic correlation between traits X and Y is considered. Assortation on trait X changes the magnitude of the genetic correlation but not its sign. There are two situations depending on the signs of the correlation between mates () and of the random mating genetic correlation (): 1) if sign () = sign (), then >, where is the genetic correlation at equilibrium after continued assortation, and 2) if sign () = sign (), then < . However, negative assortative mating is virtually powerless to alter the magnitude of the genetic correlation. The consequences of a mixed assortation model, e.g., high milk production females mated to fast growing males and lesser productive females mated to slower growing sires, were also studied. Mixed positive assortation always increases the genetic correlation, but negative assortation decreases it. The implications of assortative mating on correlated responses to selection and on the equilibrium covariances between relatives for pairs of traits are discussed.     

Reactivity of θ and α EEG Frequency Bands in Voluntary Attention in Junior Schoolchildren

Spatiotemporal organization of rhythmic and EEG components was studied by means of spectral-correlation analysis in seven- to eight-year-old children (n = 18) during anticipatory selective attention to sensory tactile and auditory stimuli. The topography of changes in coherence of the oscillations suggests that functional assemblies formed on the basis of the rhythm are modality-specific. Their centers are localized in respective sensory-specific cortical regions (central areas of both hemispheres during tactile attention and temporal areas during auditory attention). The functional integration on the basis of the rhythm is represented in both hemispheres by functional associations of the temporal, frontal, and (to a lesser extent) posterior associative areas independently of the modality of a relevant signal. Both types of the functional integration are significant for a correct solution of a perceptive task. The proposition that the cooperation of the - and systems in neuronal organization of voluntary attention ensure, respectively, its informational and motivational aspects.     

No evidence for linkage between the loci for coagulation factor XIII-A and HLA

Summary The linkage analysis between the locus for coagulation factor XIII-A (F13A) and HLA region genes (HLA-A,-C,-B) was performed. In males, the maximum of lod scores between F13A and HLA was 0.33 at =0.30, and in females lod scores were negative at all values of . The results provided no evidence for close linkage between F13A and HLA genes.     

Reduced sensitivity of Niemann-Pick C1-deficient cells to θ-toxin (perfringolysin O): sequestration of toxin to raft-enriched membrane vesicles

-Toxin (perfringolysin O) binds to cell surface cholesterol and forms oligomeric pores that cause membrane damage. Both in cytotoxicity and cell survival assays, a mutant Chinese hamster ovary cell line NPC1(–) that lacked Niemann-Pick C1 showed reduced sensitivity to -toxin, compared with wild-type (wt) cells. BC is a derivative of -toxin that retains cholesterol-binding activity but lacks cytotoxicity. Confocal and electron microscopy revealed the presence of multiple vesicles which bound BC, both on the cell surface and in the extracellular space of these cells. BC binding to raft microdomains was verified by its resistance to 1% Triton X-100 at 4°C and recovery of bound BC in floating low-density fractions on sucrose density gradient fractionation. BC-labeled vesicles were abolished when NPC1(–) cells were depleted of lipoproteins and also when treated with a Rho-associated kinase inhibitor Y-27632. In addition, similar vesicles were observed in wt cells treated with progesterone. In parallel with these results, -toxin sensitivity of NPC1(–) cells was increased when cells were depleted of lipoproteins or treated with Y-27632, whereas that of wt cells was decreased by progesterone. Our findings suggest that sequestration of toxin to raft-enriched cell surface vesicles may underlie reduced sensitivity of NPC1-deficient cells to -toxin.     

Mapping dominant markers using F2 matings

The development of efficient methods for amplifying random DNA sequences by the polymerase chain reaction has created the basis for mapping virtually unlimited numbers of mixed-phase dominant DNA markers in one population. Although dominant markers can be efficiently mapped using many different kinds of matings, recombination frequencies and locus orders are often mis-estimated from repulsion F₂ matings. The major problem with these matings, apart from excessive sampling errors of recombination frequency () estimates, is the bias of the maximum-likelihood estimator (MLE) of ( _ML). when the observed frequency of double-recessive phenotypes is 0 and the observed frequency of double-dominant phenotypes is less than 2/3 — the bias for those samples is — . We used simulation to estimate the mean bias of _ML. Mean bias is a function of n and and decreases as n increases. Valid maps of dominant markers can be built by using sub-sets of markers linked in coupling, thereby creating male and feamle coupling maps, as long as the maps are fairly dense (about 5 cM) — the sampling errors of increase as increases for coupling linkages and are equal to those for backcross matings when =0. The use of F₂ matings for mapping dominant markers is not necessarily proscribed because they yield twice as many useful markers as a backcross population, albeit in two maps, for the same number of DNA extractions and PCR assays; however, dominant markers can be more effeciently exploited by using doubled-haploid, recombinant-inbred, or other inbred populations.     

Phosphorus depletion in the rhizosphere as influenced by soil moisture

To study the influence of soil moisture on phosphorus (P) depletion in the rhizosphere, maize (Zea mays cv. Trak) was pre-grown in vermiculite filled-PVC tubes for 9 days and then the plants with the tubes were transplanted into soil columns maintained at two soil moisture levels () of 0.14 and 0.20 cm³ cm^–3 for 10 days. The soil columns were separated at 1 cm depth by a nylon screen of 53 m inner mesh size, into 1 cm soil layer above and 3 cm soil column below screen. A root mat developed over the screen, but root hairs only could penetrate it. Regardless of the soil moisture level in the columns, and adequate and equal water and nutrients supply was maintained via wicks from an external nutrient solution to the plant roots in vermiculite. After 10 days, the soil columns were separated from the root mats, quickly frozen in liquid nitrogen and sliced into thin layers (0.2mm) using a refrigerated microtome to give soil samples at defined distances from the root mats for analyses. Lower soil moisture (=0.14) resulted in narrower and steeper depletion profile of 0.5 M NaHCO₃ extractable P (NaHCO₃-P_i) as compared to higher soil moisture (=0.20). Depletion of P in soil solution in the immediate vicinity of root mats did not differ much but the extension of the depletion zones was 0.10 cm at =0.14 and 0.20 cm at =0.20. The depletion up to 0.05cm with =0.14 and up to 0.07 cm with =0.20 was uniform, and may be attributed to the depletion in the root hair zone. Beyond the root hair zones, the theory of diffusion and mass flow was able to explain the observed differences in shape and extent of the P depletion profiles at the two soil moisture levels.     

Methane production by anaerobic digestion of animal manures

Anaerobic digestion of swine manure was performed at mesophilic and thermophilic temperatures. In addition, the possibility of enhancement of biogas production by the co-digestion of manures with cellulosic waste residues (e.g., corn stover), was investigated. In the latter studies, the effect of particle size on the gasification efficiency was assessed.Methane productivity, G(m³ methane/m³ slurry volume.day), in the digesters operating at a stationary state could be correlated with the volatile solids loading, L (kg/m³.day), Retention time, (days), and pH as follows: G = L/(1 + 10^pK-pH) + [k/(1 + k)] where is dependent primarily on the nature of the utilizable carbohydrate fraction. The constant, , is found to be a function of the organic nitrogenous fraction of the manure. The constants pK and k (days^-1) are dependent on the temperature only.     

Absence of linkage between transcobalamin II and ABO

Summary In a linkage analysis of 29 pedigrees with a total of 196 individuals, absence of close linkage between transcobalamin II (TC2) and ABO is demonstrated. Recombination fraction values of 相似文献   

Nucleotide sequence of the humanθ 1-globin gene

We have cloned and sequenced the human ₁-globin gene. The nucleotide sequence and organization of the human ₁ gene (exons, introns, promoter, and polyadenylation signals) are similar to those reported for the orangutan ₁-globin gene. If these genes are functional, the sequences of their ₁-globin chains would differ by only one amino acid residue (at position 137).This research was supported by USPHS Research Grants HLB-05168 and HLB-15158. This is contribution No. 1085 from the Department of Cell and Molecular Biology at the Medical College of Georgia in Augusta.     

Use of the crossflow-microscreen technique for SCP production from dilute substrates

Summary A crossflow-microscreen cultivation technique was successfully used to select and maintain an easily harvestable microbial culture with a limited number of species under non-aseptic conditions in diluted cheese whey. The microbial selective pressure exerted by the system could be manipulated by varying the hydraulic () and mean cell () residence times. The optimum system parameters were =1 h and =10 h, resulting in a selected microbial population comprising three species only, namely Geotrichum candidum, Streptococcus cremoris and Leuconostoc lactophilum. The amino acid profile of the SCP produced compared favourably with other types of protein. The crossflow-microscreen technique makes SCP production possible from dilute, waste organic effluents.     

Spectral Analysis of the Human EEG during Listening to Musical Compositions

A reorganization of the spectral power (SP) of the human brain potentials takes place during listening to music. The characteristic features of the reorganization depend on the type of the musical composition. Listening to classical music (of low and moderate intensity) produces an increase in the SP of the high-frequency EEG (₂, ₁, ₂, and bands) widely generalized over the brain cortex. Listening to rock music (of moderate and high intensity) produces an increase in the SP predominantly in the and ₁ frequency bands. There were variations within each EEG pattern caused by different intensity of the music listened to.     

Spectral Characteristics of the EEG in Students with Different Levels of Result Achievement under the Conditions of Examination Stress

The EEG correlates of the performance of examination tests and special cognitive tests under the conditions of everyday study (common studying conditions, CSCs) and immediately before examination (examination conditions, ECs) were analyzed in 39 male students aged 18–20 years. The results of the examinations strongly correlated with the relative spectral power (SP) of the EEG rhythm before the examination. Therefore, the students were divided into two groups with different directions of changes in the -range SP under the ECs compared to the CSCs. Students from group 1 were characterized by increased relative - and -rhythm SPs under the ECs and a good examination performance; students of group 2, by decreased - and -rhythm SPs, an increased index of the EEG of the central and frontal cortical regions under the ECs, and a poor examination performance.     

Linkage analysis for 18 enzyme loci in Pinus rigida Mill.

Summary Estimates of recombination frequency among enzyme loci of pitch pine revealed two new linkages, Mdh3:Pgm2 (=0.01) and Pep1:Mdh4 (=0.38), and confirmed two previously established linkages. Tighter linkage (=0.30) was ruled out for nearly all gene pairs examined. In general, the Bayesian approach used in this study to test for linkage performed better than alternative methods.This work was supported by the School of Natural Resources, College of Agricultural and Life Sciences, University of Wisconsin, Madison, WI, and by McIntyre-Stennis, project no. 142-C385     

New markers for linkage analysis of X-linked hypophosphataemic rickets

Three polymorphic markers have been used to improve the genetic map of the region Xp22.1-p22.2, which contains the HYP (hypophosphataemic rickets) locus. DXS365 gave no recombinants with HYP, with a peak Lod score of 5.4 at = 0.0. A microsatellite marker mPA274 was derived for the DXS274 locus; it detects five alleles with a polymorphism information content of 0.55. Combining information from this microsatellite and the original DXS274 marker, probe CRI-L1391, the peak Lod score for DXS274 against HYP was 9.6 at = 0.02. A microsatellite associated with the DXS207 locus (mPA207) gave a peak lod score against HYP of 4.7 at = 0.14. A consideration of key recombinants and multilocus analysis suggests the gene order: Xpter-DXS207-DXS43-DXS197-(DXS365, HYP)-DXS274-DXS41-Xcen.     

A method for the investigation of those transformations under which the visual recognition of a given object is invariant

An experiment is described which shows in operation the program set out in Foster (1972a) for the investigation of the invariance transformations of visual recognition. The concern in the present study is with the Lie group of rotations SO(2), and a certain centrally located foveal Landolt ring. By presenting to the visual system this Landolt ring and a rotated image in rapid succession, one attempted to induce a specified rotation-type phi-motion. Two subjects were employed. Both reported the existence of the required type of phi-motion for rotations ₀ of the Landolt ring about the visual axis with -2/72/7. By appealing to the basic Proposition 2 of Foster (1972 a), the conclusion is reached that the visual system appears capable of effecting upon a certain centrally located foveal annulus the local 1-parameter group of rotations about the visual axis ₀, [–2/7,2/7].     

High-level Expression of Maize <Emphasis Type="Italic">γ</Emphasis>-zein Protein in Transgenic Soybean (<Emphasis Type="Italic">Glycine max</Emphasis>)

Primers were developed for 118 microsatellites isolated from grape (Vitis vinifera) genomic libraries enriched for (AC)n repeats. Only one microsatellite sequence matched other grape SSR-sequences in the GeneBank database. Genotyping was carried out in the parental lines and four offspring of two pseudo-test-cross populations, Cabernet Sauvignon x Seyval and Chardonnay x Bianca, and a further six other grape genotypes (V. vinifera Sultanina, Merlot, Syrah, Müller-Thurgau, Vitis Regent and V. riparia Gloire de Montpellier). A total of 108 microsatellites showed easily scorable alleles and 100 of them segregated according to a configuration suitable for mapping in either cross. A further 8 SSRs, although unsuitable for mapping in those crosses, showed polymorphism in the other genotypes tested. This set of markers was used, along with 75 microsatellites of other repeat-types, to fingerprint 46 offspring of the cross Chardonnay x Bianca. For each full-sib, individual heterozygosity and distance in repeat units between pairs of alleles at each locus (mean d²) were calculated as a tool for predicting highly outbred recombinant individuals. Six microsatellites with segregation ratios significantly distorted towards the lack of homozygous sibs were identified and mapped to linkage groups LG 3 and LG 5. Estimation of heterozygosity at genome-wide level and genotyping at loci for which homozygous sibs are discriminated against are discussed for marker-assisted background selection in outcrossing grapevines.