Mapping of theHox-3.1 andMyc-1.2 genes on chromosome 15 of the mouse by restriction fragment length variations

Restriction endonuclease fragment length variations (RFLV) were detected by use of the cDNA probeHox-3.1 for the homeo box-3.1 gene and also thec-myc oncogene probe for exon 2. RFLV ofHox-3.1 were found inHindIII restriction patterns, and RFLV of theMyc-1.2 gene inEcoRV patterns. From the RFLV, theHox-3.1 andMyc-1.2 genes were mapped on chromosome 15. Three-point cross test data showed that the frequency of recombination is 26.4% betweenMyc-1.2 andGpt-1, 30.2% betweenGpt-1 andGdc-1, and 9.4% betweenGdc-1 andHox-3.1. The following order of these genes is proposed,Myc-1.2—Gpt-1—Gdc-1—Hox-3.1. All laboratory strains carry theHox-3.1 ^a andMyc-1.2 ^a alleles. Among strains of wild origin,domesticus strains carry only theHox-3.1 ^a andMyc-1.2 ^a alleles, as do the laboratory strains. One strain ofbrevirostris carries theHox-3.1 ^a andMyc-1.2 ^b alleles. Other wild subspecies from Europe and Asia,M. m. musculus, M. m. castaneus, M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai carry theHox-3.1 ^b andMyc-1.2 ^b alleles.     

Mapping of the MouseLy-6, Xp-14, andGdc-1 loci to chromosome 15

TheLy-6 locus is now regarded as a gene complex consisting of at least five closely linked loci (Ly-6A-Ly-6E) whose polymorphic products are identified by monoclonal antibodies and distinguished by different tissue distributions.Ly-6 has been assigned by other investigators to chromosome (Chr) 9 (linked toThy-1 or to Chr 2. We report that theLy-6 gene complex, together with theXp-14 andGdc -1 loci, is situated on Chr 15 linked toGpt1. These new linkage data are derived from four sources: (1) three separate crosses that failed to demonstrate linkage ofLy-6 to eitherThy-4 on Chr 9 or to any of five genes present on Chr 2; (2) the NXSM recombinant inbred strains, which suggested the linkage ofLy-6 andXp-14 toGpt-1 on Chr 15; (3) severalGpt-1 andGdc-1 congenic strains that confirmed the assignment ofLy-6 andXp-14 to Chr 15; and (4) backcrosses that further confirmed the linkage ofLy-6, Gpt-1, Gdc-4, andXp-14, the probable gene order beingGpt-11/Ly-6 Xp-14-Gdc-1.     

Assignment of Lap-1 to linkage group I of the rat (Rattus norvegicus)

Genetic analysis of backcross progeny from previously characterized rat inbred strains revealed that the biochemical marker Lap-1 is localized in linkage group I (LG I). Lap-1 codes for leucine arylaminopeptidase (EC 3.4.11). The distances of Lap-1 to c, RT6, and Hbb, based on recombination frequencies, are 3.1±1.5, 8.3±4.0, and 11.4±2.8 cM, respectively. Acon-1 codes for aconitase (EC 4.2.1.3). The calculated distances of Acon-1 to c and Hbb are 30.1±5.0 and 36.1±5.3 cM, respectively. This suggests that Acon-1 is also in LG I, but the observed high frequency of double crossovers requires further confirmation of this linkage. Ahd-2, Es-6, and Gdc-1 are linked neither to markers of LG I nor to one another.     

Assignment of the Ly-6--Ril-1--Sis--H-30--Pol-5/Xmmv-72--Ins-3--Krt-1--Int-1--Gdc-1 region to mouse chromosome 15

Previous work has demonstrated linkage between Ly-6, H-30, and a locus, Ril-1, that affects susceptibility to radiation-induced leukemia. Results of preliminary linkage analyses suggested further that the cluster might be linked to Ly-11 on the proximal portion of mouse chromosome 2. Using molecular probes to examine somatic cell lines and recombinant inbred and congenic strains of mice, we have re-evaluated these linkage relationships. A cloned genomic DNA fragment derived from a retroviral site has been used to define a novel locus, Pol-5, that is tightly linked to both H-30 and Ril-1 as shown by analysis of the B6.C-H-30 ^c congenic mouse strain. Following the segregation of the Pol-5 mouse-specific DNA fragment in a series of somatic cell hybrids carrying various combinations of mouse chromosomes on a rat or Chinese hamster background mapped Pol-5 to mouse chromosome 15. During the course of these studies, restriction fragment length polymorphisms were defined associated with several loci, including Pol-5, Ly-6, Sis, Ins-3, Krt-1, Int-1, and Gdc-1. Three of these loci, Sis, Int-1, and Gdc-1, have been previously mapped to chromosome 15 by others using somatic cell hybrids or isoenzyme analyses. Following the inheritance of these eight loci in recombinant inbred strains of mice allowed the definition of a linkage group on the chromosome with the order Ly-6-Ril-1--Sis--H-30--Pol-5--Ins-3--Krt-1--Int-1--Gdc-1. Analyses of alleles inherited as passengers in B6.C-H-30 ^c, C3H.B-Ly-6 ^b, and C57BL/6By-Eh/+ congenic mouse strains and in situ hybridization experiments support the above gene order and indicate further that the cluster is located on distal chromosome 15, with Ly-6 and Sis near Eh.Abbreviations A agouti - Abl cellular homolog of the Abelson leukemia virus oncogene - Ada adenosine deaminase - Ak-1 adenylate kinase-1 - AXB A/J × C57BL/6J recombinant inbred strain - B2m beta-2 microglobulin - BXA C57BL/6J × A/J recombinant inbred strain - BXD C57BL/6J × DBA/2J recombinant inbred strain - BXH C57BL/6J × C3H/HeJ recombinant inbred strain - CXB BALB/cBy × C57BL/6By recombinant inbred strain - DNA deoxyribonucleic acid - Eh hairy ears - Fpgs folypolyglutamyl synthetase - FXI fractionated x-irradiation - Gdc-1 glycerol phosphate dehydrogenase-1 - Il2r IL-2 receptor - Ins-3 a novel insulinlike gene - Int-1 mammary tumor integration site-1 - Itp inosine triphosphatase - Krt-1 the locus designated here includes a cluster of at least three keratin genes - LTR long terminal repeat - Ly lymphocyte - Lv-6 lymphocyte antigen-6 - Ly-11 lymphocyte antigen-11 - MIH minor histocompatibility - Myc cellular homolog of the Abelson leukemia virus oncogene; pa, pallid; - Pol-5 locus encoding retroviral polymerase-5 - RFLP restriction fragment length polymorphism - RI recombinant inbred mouse strains - Ril-1 radiation-induced leukemia susceptibility-1 locus - SDP strain distribution pattern - Sis cellular homolog of the simian sarcoma virus oncogene - SFFV spleen focus-forming virus - Tpi-1 triosephosphate isomerase-1 - Ve velvet     

The genetics of glutamic-pyruvic transaminase in mice: Inheritance,electrophoretic phenotypes,and postnatal changes

Glutamic-pyruvic transaminase (GPT, E.C. 2.6.1.2) from 18 inbred strains of mice was subjected to starch gel electrophoresis. Two electrophoretic phenotypes were observed: a fast-migrating pattern in 16 strains and a slower-migrating pattern in two strains. A comparison of electrophoretic patterns of F₁ and backcross progeny of two strains of mice showed that the inheritance of GPT is autosomal with two codominant alleles. The genetic locus for GPT is designated Gpt-1, and its two alleles are designated Gpt-1 ^a and Gpt-1 ^b to represent the fast-migrating (A) and slow-migrating (B) patterns. The GPT was expressed in 11 tissues with different amounts of enzyme activity. Developmental studies of GPT activity in liver showed that between 5 and 12 days after birth the mean activity was 10 units/g protein. Between 12 and 19 days, a dramatic rise in activity occurred and adult values of 300 units/g protein were reached by 26 days.This research was supported by The National Foundation (CRBS-258) and the National Institutes of Health (GM15253).Preliminary results were reported at the Annual Meeting of the American Society of Human Genetics, October 11–14, 1972, in Philadelphia.R. P. D. is an investigator of the Howard Hughes Medical Institute.     

High-resolution mapping of a minor histocompatibility antigen gene on mouse chromosome 2

Minor histocompatibility (H) loci are significant tissue transplantation barriers but are poorly understood at the genetic and molecular level. We describe the construction of a high-resolution genetic map that positions a class II MHC-restricted minor H antigen locus and orders 12 other genes and genetic markers within the we-un interval of mouse Chromosome (Chr) 2. An intersubspecific backcross between 10.UW/Sn-H-3 ^b and CAST/Ei, an inbred stock of Mus musculus castaneus, was used for this purpose. A total of 1168 backcross mice were generated, and 71 we-un recombinants were identified. Significant compression of the genetic map in males versus females and transmission distortion of CAST-derived we, un, and A ^w genes were observed. Monoclonal T cell lines specific for two minor H alloantigens, Hd-1^a and Hd2^a, encoded by gene(s) that map to the we-un interval were used to antigen type the backcross mice. The results suggest the Hd-1^a and Hd-2^a antigens are most likely encoded by a single gene, now referred to as H-3b. The determined gene order is we-0.09±0.09-Itp-0.62±0.23-D2Mit77-0.26±0.15[Evi-4, Pcna, Prn-p]-0.26±0.15-Scg-1-0.44±0.19-[Bmp2a, D2Mit70]-0.09±0.09-[D2Mit19, D2Mit46]-1.59±0.36-D2Mit28-0.97±0.28-D2Lerl-1.50±0.35-H-3b-0.26±0.15-un (% recombination±1 SE). Because the average resolution of the backcross is 0.09 cM, the backcross panel should facilitate the physical mapping and molecular identification of a number of genes in this chromosome region.     

Genetic analysis of alcohol intake in recombinant inbred and congenic strains derived from A/J and C57BL/6J progenitors

The objective of the present study was to map quantitative trait loci (QTL) for alcohol intake using A × B/B × A recombinant inbred (RI) and AcB/BcA recombinant congenic (RC) strains of mice that were independently derived from the A/J and C57BL/6J progenitors. Mice were screened for levels of alcohol consumption with four days of forced exposure to alcohol, followed by three weeks of free choice between water and a 10% alcohol solution. Alcohol consumption data previously collected for 27 A × B/B × A RI strains were reanalyzed using a larger marker set and composite interval mapping. The reanalysis found markers on Chromosome 2 (D2Mit74, 107 cM) (males and females) and on Chromosome 11 (Pmv22, 8 cM) (females only) that exceeded the threshold for significant loci, and found suggestive loci (in males) on Chromosomes 10 (D10 Mit126, 21 cM), 12 (D12Mit37, 1 cM), 15 (Pdgfb, 46.8 cM), and 16 (D16Mit125, 29 cM). An additional suggestive locus was identified in female RI mice on Chromosome 11 (D11Mit120, 47.5 cM). Composite interval mapping (CIM) analysis indicated that there was a significant association between loci at Pdgfb and D2Mit74 in both males and females. Analysis of the AcB/BcA RC strains identified 11 QTL on Chromosomes 2, 3, 5,6, 7, 8, 9, 10, 12, 13, and 15. QTL on Chromosomes 7, 10, 12, and 15 were identified in both the A × B/B × A RI and AcB/BcA RC strains of mice. Additional QTLs identified on Chromosomes 2, 3, 7, 11, and 15 overlap with those previously identified in the literature using strains of mice with a C57BL/6J progenitor.     

Genetic polymorphism of the sixth component of complement (C6) in mice

Immunofixation after isoelectric focusing revealed two forms of mouse C6, C6A and C6M, both of which consist of two major protein bands and one or more acidic minor bands. They were distinguishable by their different isoelectric point (pI) ranges: C6M has more acidic pI ranges (pH < 6.2) than C6A (pH < 6.3). C6A was found in common inbred mice of Mus musculus domesticus, while C6M was found in inbred and wild mice of M. m. molossinus (Japanese wild mice, an Asian subspecies). Breeding experiments showed that these two forms of C6 were controlled by a single codominant autosomal locus. We propose the designation C-6 for this locus with two alleles, C-6 ^a and C-6 ^m , which encode for C6A and C6M, respectively. Linkage analysis indicated that the locus is not closely linked to the following loci: Idh-1, agouti, Amy-1, brown, Gpd-1, Mup-1, Pgm-2, Pgm-1, albino, Hbb, Es-1, Mod-1, Sep-1, Es-3, Igh-1, beige, Es-10, Sod-1, and C-3.     

Ecological problems of Lake Ladoga: causes and solutions

We studied the outcome of competition between a large (Brachionus calyciflorus) and a small (Anuraeopsis fissa) rotifer species at five algal (Scenedesmus acutus) concentrations (0.5 × 10⁶ to 40.5 × 10⁶ cells ml^–1) and with varying initial densities in mixed populations (100 to 0% of B. calcyciflorus or A. fissa), the combined initial biomass being 0.2 µg ml^–1 in all test jars. Experiments were conducted at 28 ± 1 °C.Regardless of food concentration, B. calcyciflorus showed a greater increase in biomass than A. fissa, peak densities (mean ± standard error) at the lowest food concentration in the controls being 1.34 ± 0.31 µg dry weight ml^–1 and 0.82 ± 0.08 dry weight ml^–1, respectively. At the lower food concentrations, A. fissa displaced B. calyciflorus and vice versa at the higher food concentrations. At the intermediate food concentrations of 4.5 × 10⁶ cells ml^–1, B. calyciflorus outcompeted A. fissa only if its initial population density was three times higher. The rates of population growth in controls varied from 0.792 ± 0.06 d^–1 to 1.492 ± 0.13 d^–1 for B. calyciflorus and 0.445 ± 0.04 to 0.885 ± 0.01 for A. fissa depending on food level. When both species were introduced together, low food levels favoured higher abundance of A. fissa than B. calyciflorus, suggesting, in nature, it is likely that small Anuraeopsis colonize oligotrophic water bodies more successfully than larger Brachionus. The results also suggest that the outcome of competition depends not only on the size of the competing species and food availability but also on their colonizing density.     

Mapping the gene for LTW-4, a 26,000 molecular weight major protein of mouse liver and kidney

Summary The polypeptide LTW-4 has previously been shown by 2D electrophoresis to be a major soluble protein of mouse liver. We now show that it is a major soluble polypeptide of mouse kidney. The Ltw-4 locus has been mapped on Chromosome 1 using the BXD, AKXL and BXH recombinant inbred strains. The gene order is Dip-1-Rnr-(Sas-1, ald)-Ltw-4-Mls. The map distance between (Dip-1, Rnr) and Ltw-4 is estimated to be 12.2±4.2 cM, between Sas-1 and Ltw-4 5.4±2.6, between ald and Ltw-4 7.1±4.6 cM, and between Ltw-4 and Mls 4.3±2.0 cM. The strain distribution pattern of Ltw-4 is reported for the SWXL recombinant inbred strains and for a large number of inbred strains of mice.     

Effect of salinity on competition between the rotifers Brachionus rotundiformis Tschugunoff and Hexarthra jenkinae (De Beauchamp) (Rotifera)

We studied the effect of different concentrations (0, 3, 6, 9 and 12 g l^–1) of sodium chloride at one food level of Chlorella (1×10⁶ cells ml^–1) on competition between the rotifers B. rotundiformis and H. jenkinae, both of which were isolated from a saline lake. The population growth experiments were conducted for 3 weeks. Both the rotifer species did not survive beyond one week at a salinity of 0 g l^–1. Regardless of salt concentration and the presence of a competitor, H. jenkinae reached higher densities than B. rotundiformis. When grown alone, both B. rotundiformis and H. jenkinae showed optimal peak population densities at the salinity of 6 and 9 g l^–1. Since biomass wise, B. rotundiformis was larger than H. jenkinae, it showed a lower numerical abundance. Thus, the maximum peak population densities of B. rotundiformis and H. jenkinae recorded in this study were 107±3 and 203±28 ind. ml^–1. The maximal rates of population increase for B. rotundiformis and H, jenkinae when grown alone were 0.264±0.003 and 0.274±0.004, respectively. Our results also indicated that B. rotundiformis and H. jenkinae coexisted better at a salinity of 6 and 9 g l^–1 of sodium chloride while a salinity of 3 g l^–1 favoured Hexarthra over B. rotundiformis. At 12 g l^–1, both the rotifer species grown alone or together showed lower growth rates compared to those at lower salinity levels. Except 0 g l^–1, in all other salinity treatments, H. jenkinae was a superior competitor to B. rotundiformis.     

Population growth of some genera of cladocerans (Cladocera) in relation to algal food (Chlorella vulgaris) levels

We studied the patterns of population growth of 7 cladoceran species (Alona rectangula, Ceriodaphnia dubia, Daphnia laevis, Diaphanosoma brachyurum, Moina macrocopa, Scapholeberis kingi and Simocephalus vetulus) using 6 algal densities, viz. 0.05×10⁶, 0.1×10⁶, 0.2×10⁶, 0.4×10⁶, 0.8×10⁶ and 1.6×10⁶ cells ml^–1, of Chlorella vulgaris for 18 – 30 days. In terms of carbon content these algal concentrations corresponded to 0.29, 0.58, 1.16, 2.33, 4.65 and 9.31 g ml^–1, respectively. Cladocerans in the tested range of algal levels responded similarly, in that increasing the food concentrations resulted in higher numerical abundance and population growth rates (r). The peak population densities were (mean±standard error) 71±5; 17.1±0.4, 3.6±0.3, 12.7±1.1, 18.2±2.7, 15.8±1.0 and 10.9±0.02 ind. ml^–1, respectively for A. rectangula, C. dubia, D. laevis, D. brachyurum, M. macrocopa, S. kingi and S. vetulus. In general, the lowest r values were obtained for D. laevis (0.01±0.001) at 0.05×10⁶ cells ml^–1 food level while the highest was 0.283±0.004 for A. rectangula at 1.6×10⁶ cells ml^–1 of Chlorella. When the data of peak population density for each cladoceran species were plotted against the body length, we found an inverse relation, broadly curvilinear in shape. From regression equations between the food level and rate of population increase, we calculated the theoretical food quantity (the threshold level) required to maintain a zero population growth (r = 0) for each cladoceran species, which varied from 0.107 to 0.289 g ml^–1 d^–1 depending on the body size. When we plotted the cladoceran body size against the corresponding threshold food levels, we obtained a normal distribution curve. From this it became evident that for up to 1300 m body size, the threshold food level increased with increasing body size; however, beyond this, the threshold level decreased supporting earlier observations on rotifers and large cladocerans.     

High-Resolution Linkage Map in the Vicinity of the Host Resistance Locus Bcg

The mouse chromosome 1 locus Bcg determines natural resistance/susceptibility of inbred mouse strains to infection with antigenically unrelated intracellular parasites, including several Mycobacterium species, Salmonella typhimurium, and Leishmania donovani. In our effort to clone Bcg, we have constructed a high-resolution genetic linkage map in the vicinity of the gene. We have developed eight new highly polymorphic markers (simple sequence repeats) corresponding to cloned genes (Vil, Inha, Des), microdissected chromosome 1 anonymous probes (λMm1C136, λMm1C163, λMm1C165), or novel DNA markers from the region obtained by chromosome walking (D1Mcg101 and D1Mcg105). We have followed the cosegregation of these markers with respect to Bcg in a novel panel of 1000 (C57L/J × C57BL/6J) × C57BL/6J segregating backcross mice. Additional segregation analyses were carried out in preexisting panels of intra- and interspecific backcross mice and recombinant inbred strains. Three of these markers were found to be very tightly linked to Bcg: λMm1C165 did not show recombination with Bcg in 1424 meioses analyzed, while D1Mcg105 and λMm1C136 were located 0.1 cM proximal and 0.2 cM distal to Bcg, respectively. This analysis enabled us to define further the proximal and distal boundaries of the Bcg interval: the proximal limit was defined by a single crossover occurring between D1Mcg105 and Bcg/λMm1C165/Vil, and the distal limit by 1 crossover between Bcg/λMm1C165/Vil and λMm1C136 in 1683 and 575 informative meioses, respectively, for a maximal interval of 0.3 cM. Combined pedigree analyses for the 30-cM segment overlaping Bcg on mouse chromosome 1 indicated the locus order and the interlocus distances (in cM): centromere-Col3a1-(8.8)-Cryg-(2.6)- λMm1C163 -(1.6)-Fn-1-(2.0)-Tp-1- (1.O)-D1Mcg105-(O.1)-λMm1C165/Vil/Bcg-(O.2)-λMm1C136-(0.3)-Des/D1Mit7-(0.1)-Inha-(2.8)-λMm1C153-(2.4)-λMm1C156-(1.2)-Pax-3-(5.6)-Akp-3-(O.8)-Acrg-(2.0)-Sag-(O.5)-Col6a3.     

Adaptive mechanisms during food restriction in <Emphasis Type="Italic">Acomys russatus</Emphasis>: the use of torpor for desert survival

The golden spiny mouse (Acomys russatus) is an omnivorous desert rodent that does not store food, but can store large amounts of body fat. Thus, it provides a good animal model to study physiological and behavioural adaptations to changes in food availability. The aim of this study was to investigate the time course of metabolic and behavioural responses to prolonged food restriction. Spiny mice were kept at an ambient temperature of 27°C and for 3 weeks their food was reduced individually to 30% of their previous ad libitum food intake. When fed ad libitum, their average metabolic rate was 82.77±3.72 ml O₂ h^–1 during the photophase and 111.19±4.30 ml O₂ h^–1 during the scotophase. During food restriction they displayed episodes of daily torpor when the minimal metabolic rate gradually decreased to 16.07±1.07 ml O₂ h^–1, i.e. a metabolic rate depression of approximately 83%. During the hypometabolic bouts the minimum average body temperature T_b, decreased gradually from 32.6±0.1°C to 29.0±0.4°C, with increasing duration of consecutive bouts. In parallel, the animals increased their activity during the remaining daytime. Torpor as well as hyperactivity was suppressed immediately by refeeding. Thus golden spiny mice used two simultaneous strategies to adapt to shortened food supply, namely energysaving torpor during their resting period and an increase in locomotor activity pattern during their activity period.     

Combined Effects of Food Concentration and Temperature on Competition Among Four Species of <Emphasis Type="Italic">Brachionus </Emphasis>(Rotifera)

We evaluated the effect of algal food density (1.5 × 10⁶, 3.0 × 10⁶ and 4.5 × 10⁶ cells ml⁻¹ of Chlorella) and temperature (22° and 28 °C) on competition among the rotifers Brachionus calyciflorus, Brachionus havanaensis, Brachionus patulus and Brachionus rubens, based on population growth experiments for 24 days. The growth experiments were conducted seperately for each individual rotifer species (i.e., controls), and in mixtures of all four species in equal initial proportions (i.e., under competition). The population growth of B. calyciflorus, B. havanaensis, B. patulus and B. rubens grown separately at two temperatures and at three algal food densities showed typical patterns of lag, exponential and retardation phases in the controls. This pattern differed considerably under competition. In general, we observed that in all of the test species, the highest growth rates were observed at higher food levels and in the absence of congenerics. At 22 °C, under the lowest food level, the differences in the population abundances of B. havanaensis, B. patulus and B. rubens grown alone and in the presence of competition were large. However, these differences reduced as food density was increased from 0.5 × 10⁶ to 4.5 × 10⁶ cells ml⁻¹. At 28 °C and at the lowest food level, all of the other rotifer species eliminated B. havanaensis in mixed cultures. Each brachionid species had a higher rate when grown alone than when cultured with other species. The highest r (mean ± standard error: 0.54 ± 0.01 day⁻¹) was recorded for B. havanaensis at 28 °C under 4.5 × 10⁶ cells ml⁻¹ of algal food density. At 28 °C at low algal food density, the presence of competitors resulted in negative population growth rates for three of the four rotifer species tested.     

Genetic chasing of T helper cell idiotype and allotype genes

The present experiments were performed to study whether the genes responsible for the expression of T-cell idiotypes and allotypes could be mapped in relation to immunoglobulin (Ig) heavy chain V- and C-genes. Use was made of our antiserum 5936, which detects idiotypes in B6 anti-B10.BR sera and on Lyt-1⁺, 2.3^–B6 anti-B10.BR T-cell populations, and antiserum 6036, which detects allotypes on Lyt-1⁺, 2.3^–B6 T cells, but which does not react against Ig. The reactivity of these antisera with T cells from (B6 x C3H.OH) x C3H.OH backcross mice and CBA-allotype congenic B6 mice was investigated because 5936 idiotypes and 6036 allotypes appeared to be associated with Igh-1 ^b genes (B6) and not with Igh-1 ^b genes (C3H.OH, CBA). Our results will show, first, that 5936 idiotypes on Lyt-1⁺, 2.3^–B6 anti-B10.BR T cells are synthesized by genes linked to Igh-1 ^b allotype genes and they are situated either within Ig heavy chain V-genes or centromeric to them. Second, our results will show that 6036 allotypes on Lyt-1⁺, 2.3^–B6 T cells are produced by genes also linked to Igh-1 ^b -allotype genes, and the 6036 allotype genes are situated between Ig-VH and prealbumin genes.Abbreviations used in this paper BCGF B cell growth factor - B6 C57B1/6 - C_H constant region of immunoglobulin heavy chain - Con A concanavalin A - FCS fetal calf serum - Id idiotype - Ig immunoglobulin - LPS lipopolysaccharide - M mouse - MHC major histocompatibility complex - MLC mixed lymphocyte culture - MRBC mouse red blood cells - NMS normal mouse serum - NP nitrophenacetyl - NRS normal rabbit serum - PFC plaque forming cell - R rabbit - Tcf T cell factor - Tcr T cell receptor - TNP Trinitrophenol - V_H variable region of Ig heavy chain Definitions of terms used in this paper: T-cell idiotypes, structures on T-cell membranes or released T-cell molecules detected by an anti-idiotypic antiserum (5936) produced against specific immunoglobulin idiotypes. The 5936 T-cell idiotypes are related to the specific binding of IA^k gene products by certain Igh-1^b T cells. T cell allotypes, structures on T-cell membranes or released T-cell molecules detected by an antiserum (6036) produced against 5936 idiotype-bearing T-cell molecules. The 6036 T-cell allotypes are related to the binding by Igh-1^b T cells of all Ia gene products tested, and they are non-cross-reactive with immunoglobulin allotypes.     

Effects of fourH-2K mutations on virus-induced antigens recognized by cytotoxic T cells

Lysis of ectromelia- or LCM virus-infected macrophage target cells by virus-specific cytotoxic T cells from mice immunized with the homologous virus occurred only where donors of T cells and target cells shared eitherH-2K orH-2D genes. With both viruses, use of T cell or target cell donors bearing mutations (B6.C-H-2^ba, B6-H-2^bh, B6-H-2^bg1, and B6-H-2^bg2), all of which apparently occurred in the same single genetic element in theH-2K^b region, abolished (H-2^ba) or impaired (H-2^bh,H-2^bg1 andH-2^bg2) lysis in T cell-target cell combinations that shared (apart from the mutations) all other genes in theK, I-A, orI-B regions of theH-2 complex. The data suggest that virus-induced antigenic patterns on infected B6.C-H- 2^ba (mutant) cells are more different antigenically from those on C57BL/6 (wild type) cells than are those on infected cells from the other mutants -B6-H-2^bh, B6-H-2^bg1, and B6-H-2^bg2. (B6.C-H-2^ba× B6 -H-2^bh)F₁ mice behaved like B6-H-2^bh, indicating no complementation, and confirming that theH-2K gene(s) involved in recognition of virus-infected cells by virus-specific T cells behave as a single element. These findings are discussed in relation to the nature of virus-induced antigenic patterns that are recognized by virus-specific cytotoxic T cells.     

Histidine decarboxylase phenotypes of inbred mouse strains: A regulatory locus (Hdc) determines kidney enzyme concentration

Mouse kidney histidine decarboxylase (HDC) provides a model system to study genetic control of a hormone-regulated enzyme (inducible by estrogen and thyroxine; repressible by testosterone). Five major HDC phenotypes scored on the basis of (i) enzyme activity and (ii) the difference in activity between the sexes (females usually higher than males) have been discovered by screening 38 strains of mice. One genetic difference between high-activity strains (DBA/2 and C3H/He) and low-activity strains (C57BL/6 and C57BL/10) has been examined in detail. The phenotypic difference segregates as a single gene in both conventional crosses and between recombinant inbred (RI) strains. Immunoprecipitation has shown that the activity difference is due to an alteration in the number of enzyme molecules. The phenotypic difference between high and low strains can therefore be attributed to different alleles of a single regulatory locus, Hdc; the alleleHdc ^d determines low HDC concentration, and the allele Hdc ^d high concentration. Hdc has been mapped to chromosome 2 using data from both comparisons of strain distribution patterns of previously mapped loci within RI strains and a conventional three-point cross. The probable gene order is B2m-pa-Hdc, with map distances of 3.1±1.7 and 2.0±1.4 cM, respectively.This work was supported by an MRC project grant to Grahame Bulfield, an SERC research studentship to S. A. M. Martin, and NIH Research Grant GM 18684 from the National Institute of General Medical Sciences to B. A. Taylor. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory animal care.     

Enzymatic synthesis of novel branched sugar alcohols mediated by the transglycosylation reaction of pullulan-hydrolyzing amylase II (TVA II) cloned from Thermoactinomyces vulgaris R-47

Transglycosylation reactions are useful for preserving a specific sugar structure during the synthesis of branched oligosaccharides. We have previously reported a panosyl unit transglycosylation reaction by pullulan-hydrolyzing amylase II (TVA II) cloned from Thermoactinomyces vulgaris R-47 (Tonozuka et al., Carbohydr. Res., 1994, 261, 157–162). The acceptor specificity of the TVA II transglycosylation reaction was investigated using pullulan as the donor and sugar alcohols as the acceptor. TVA II transferred the α-panosyl unit to the C-1 hydroxyl group of meso-erythritol, C-1 and C-2 of xylitol, and C-1 and C-6 of d-sorbitol. TVA II differentiated between the sugar alcohols’ hydroxyl groups to produce five novel non-reducing branched oligosaccharides, 1-O-α-panosylerythritol, 1-O-α-panosylxylitol, 2-O-α-panosylxylitol, 1-O-α-panosylsorbitol, and 6-O-α-panosylsorbitol. The Trp³⁵⁶→Ala mutant showed similar transglycosylation reactions; however, panose production by the mutant was 4.0–4.5-fold higher than that of the wild type. This suggests that Trp³⁵⁶ is important for recognizing both water and the acceptor molecules in the transglycosylation and the hydrolysis reaction.     

Thermoregulation in three species of Afrotropical subterranean mole-rats (Rodentia: Bathyergidae) from Zambia and Angola and scaling within the genus Cryptomys

The thermoregulatory characteristics of three species of Cryptomys from Zambia and Angola are examined and, together with published data on four other species of Cryptomys from southern Africa, used to determine whether scaling occurs in this genus of subterranean rodents. The thermoregulatory properties of acclimated giant Zambian mole-rats, Cryptomys mechowi ( =267 g), Angolan mole-rats, Cryptomys bocagei ( =94 g) and Zambian common mole-rats Cryptomys hottentotus amatus ( =77 g) are as follows. Mean resting metabolic rates (RMRs) within the respective thermoneutral zones were 0.60±0.08 cm³ O₂ g^-1 h^-1 (n=12) for C. mechowi; 0.74±0.06 cm³ O₂ g^-1 h^-1 (n=8) for C. bocagei and 0.63±0.06 cm³O₂ g^-1 h^-1 (n=21) for C. h. amatus. The thermoneutral zones (TNZs) of all three species are narrow: 29–30°C for C. mechowi; 31.5–32.5°C for C. bocagei and 28–32° C for C. h. amatus. The increase in mean RMR at the lowest temperatures tested (15° C for C. mechowi, 18° C for C. bocagei and C. h. amatus) was 2.35, 2.2 and 3.82 times their RMR in the TNZ respectively. Body temperatures are low, 34±0.53° C (n=24) for C. mechowi, 33.7±0.32° C (n=20) for C. bocagei and 33.8±0.43° C (n=40) for C. h amatus. At the lower limit of thermoneutrality, conductances are 0.09±0.01 cm³ O₂ g^-1 h^-1 °C^-1 (n=30) in C. mechowi; 0.12±0.01 cm³ O₂ g^-1 h^-1 °C^-1 (n=20) in C. bocagei and 0.12±0.03 cm³ O₂ g^-1 h^-1 °C^-1 (n=32) in C. h. amatus. The range in mean body mass among the seven species of Cryptomys examined for scaling was 60 g (C. darlingi) to 267 g (C. mechowi). There is no clear relationship between RMR within the TNZ and body mass. The resultant relationship is represented by the power curve RMR=2.45 mass^-0.259.