Location ofMls locus on mouse chromosome 1

Linkage between theMls locus and the chromosome 1 markersDip-1 andald was detected using two sets of recombinant inbred strains. Linkage betweenMls andDip-1 was confirmed in the fifth and sixth backcross generations of an incipient congenic strain. The AKXL data indicate that the gene order isDip-1-ald-Mls. The recombination frequency betweenald andMls is estimated to be 0.07 ±0.05, based on the AKXL data. The recombination frequency betweenDip-1 andMls is estimated to be 0.18 ±0.04, based on all the available data.     

Control of the rate of phosphocreatine resynthesis after exercise in trained and untrained human quadriceps muscles

We examined the effect of differences in exercise intensity on the time constant (t _c) of phosphocreatine (PCr) resynthesis after exercise and the relationships betweent _c and maximal oxygen uptake (VO_2max) in endurance-trained runners (n = 5) and untrained controls (n = 7) (average VO_2max = 66.2 and 52.0 ml · min^–1 · kg^–1, respectively). To measure the metabolism of the quadriceps muscle using phosphorus nuclear magnetic resonance spectroscopy, we developed a device which allowed knee extension exercise inside a magnet. All the subjects performed four types of exercise: light, moderate, severe and exhausting. The end-exercise PCr: [PCr + inorganic phosphate (P_i)] ratio decreased significantly with the increase in the exercise intensity (P < 0.01). Although there was little difference in the end-exercise pH, adenosine diphosphate concentration ([ADP]) and the lowest intracellular pH during recovery between light and moderate exercise, significant changes were found at the two higher intensities (P < 0.01). These changes for runners were smaller than those for the controls (P < 0.05). The _c remained constant after light and moderate exercise and then lengthened in proportion to the increase in intensity (P < 0.05). The runners had a lowert _c at the same PCr and pH than the controls, particularly at the higher intensity (P < 0.05). There was a significant correlation betweent _c and [ADP] in light exercise and betweent _c and both end-exercise PCr and pH in severe and exhausting exercise (P < 0.05). The threshold of changes in pH andt _c was a PCr: (PCr + P_i) ratio of 0.5. There was a significant negative correlation between the VO_2max andt _c after all levels of exercise (P<0.05).However, in the controls a significant correlation was found in only light and moderate exercise (P < 0.05). These findings suggest the validity of the use oft _c at an end-exercise PCr:(PCr + P_i) ratio of more than 0.5 as a stable index of muscle oxidative capacity and the correlation between local and general aerobic capacity. Moreover, endurance-trained runners are characterized by the faster PCr resynthesis at the same PCr and intracellular pH.     

Duplication of the structural gene for glucosephosphate isomerase and phosphogluconate dehydrogenase inScabiosa columbaria and their phylogenetic implications in the dipsacaceae

Zymograms of glucosephosphate isomerase (GPI) and phosphogluconate dehydrogenase (PGD) revealed three isozymes for each enzyme in the plant speciesScabiosa columbaria. Intergenic heterodimers are formed between the polypeptides coded byGpi-1 andGpi-2 and between those coded byPgd-1 andPgd-2, indicating that a GPI and a PGD locus have been duplicated in the past. The ancestral genes assort independently with their duplicated gene, suggesting that the duplications have originated from a process of translocation. Linkage was found only betweenGpi-1 andPgd-2 and betweenGpi-2 andPgd-1, suggesting that the duplicated loci were located on the same translocated chromosomal segment. Both duplications are present in all other examined species ofScabiosa and inCephalaria andKnautia, two other genera of the Dipsacaceae. The generaSuccisa andDipsacus, also belonging to the Dipsacaceae, do not showGpi-1 activity, makingGpi-2 andPgd-1 the most likely ancestral genes. InSuccisa, the isozymes ofGpi-1 andGpi-2 either overlap orGpi-1 has been silenced. The combined results suggest that a chromosomal segment containingGpi-2 andPgd-1 has been translocated before the divergence ofScabiosa, Cephalaria, Knautia, andSuccisa.     

Genetic Characterization of the Chromosomal Rearrangements That Accompany the Transgene Insertion in theChakragatiMouse Mutant

We have previously reported that the circling phenotype of thechakragatimouse segregates with the transgene integration event as an autosomal recessive trait. It was unclear, however, whether the phenotype was linked to the transgene integration point nearD16Ros1or to a potential disruption atD16Ros2,10 cM away. We report here that animals recombinant betweenD16Ros1andD16Ros2,homozygous for the transgene insertion atD16Ros1,but wildtype forD16Ros2,do indeed show the phenotype. We conclude that any potential disruption at theD16Ros2locus is not responsible for the circling phenotype. We further show that recombination betweenD16Ros1andD16Ros2occurs at a greatly reduced level in thechakragatimouse compared to wildtype strains. Detailed genetic analysis of recombinants indicates that the proximal-most 4.5 cM shows no recombination in over 1400 meioses. We propose that this is due to an inversion in this region, and we genetically define the proposed distal inversion break point to a 1.3-cM region betweenD16Mit63andD16Mit169.     

Inositol bisphosphate and inositol trisphosphate inhibit cell-to-cell passage of carboxyfluorescein in staminal hairs ofSetcreasea purpurea

pH-buffered carboxyfluorescein (Buffered-CF) alone (control), or Buffered-CF solutions containing one of the following: (1)d-myo-inositol (I); (2)d-myo-inositol 2-monophosphate (IP₁); (3)d-myo-inositol 1,4-bisphosphate (IP₂); (4)d-myo-inositol 1,4,5-trisphosphate (IP₃); (5)d-fructose 2,6-diphosphate (F-2,6P₂) were microinjected into the terminal cells of staminal hairs ofSetcreasea purpurea Boom. Passage of the CF from this terminal cell along the chain of cells towards the filament was monitored for 5 min using fluorescence microscopy and quantified using computer-assisted fluorescence-intensity video analysis. Cell-to-cell transport of CF in hairs microinjected with Buffered-CF containing either I, IP₁ or F-2,6P₂ was similar to that in hairs microinjected with Buffered-CF only. On the other hand, cell-to-cell transport of CF in hairs microinjected with Buffered-CF containing either IP₂ or IP₃ was inhibited. These results indicate that polyphosphoinositols may be involved in the regulation of intercellular transport of low-molecular-weight, hydrophilic molecules in plants.Abbreviations CF 5(6)Carboxyfluorescein - DG diacylglycerol - F2, 6P₂ d-fructose 2,6-diphosphate - I d-myo-inositol - IP₁ d-myo-inositol 2-monophosphate - IP₂ d-myo-inositol 1,4-bisphosphate - IP₃ d-myo-inositol 1,4,5-trisphosphate     

Location of the structural gene for glycyl ribonucleic acid synthetase by means of a strain ofEscherichia coli possessing an unusual enzyme

Summary E. coli KB (Benzer) differs from other common laboratory strains in possessing a glycyl sRNA synthetase with a 50 to 100 times elevated K _m for glycine. The degree of charging of glycyl sRNA in this strain can be increased by supplementing the growth medium with glycine. The altered enzyme has been used as a marker by which to map its structural gene. Linkage analysis of recombinants from uninterrupted matings, and cotransduction (80%) of the synthetase withxyl, indicate that this gene is located betweenxyl andmalt, close toxyl, at min 69.5 on the map drawn byTaylor andThoman (1964).     

Genetics of black gram (Phaseoulus mungo L.)

In black gram, the mode of inheritance of six pairs of characters has been analysed, viz.: erect versus spreading habit; hairy versus glabrous fruit; bluish black versus straw fruit colour; shiny versus dull seed surface; green versus brown seed colour. On the basis of the results, the following gene symbols are proposed:Erect habitSp is incompletely dominant over spreading,sp.—Hairy fruitG is dominant over glabrous,g, while inG plants the extent of hairiness is controlled by more than one pair of genes.—Bluish black fruit colourS is dominant over straw,s.—Shiny seed surfaceD is dominant over dull,d.—Green seed colourBr is dominant over brown;br.—Mosaic colour pattern of the seedUc is dominant over non-patterned,uc.Linkage was observed betweenS andUc, as well as betweenBr andD.     

On antigenic H-relationships between the groupsSalmonella,Arizona andEscherichia coli

Summary Results of a study on H-relationships between the groupsSalmonella (a-z₄₄),Arizona (1, ... −40) andE. coli (1–48) are given. By means of cross agglutination and cross absorption tests, strong relationships betweenSalmonella andArizona were demonstrated, while no H-antigen relationships could be observed betweenE. coli and the groupsSalmonella andArizona.     

Evidence for a specific fructose carrier inRhodotorula glutinis based on kinetic studies with a mutant defective in glucose transport

The mutant R₃₃ of the obligatory aerobic yeastRhodotorula glutinis exhibited a defect ind-glucose uptake. Detailed kinetic studies ofd-glucose andd-fructose transport in wild-type and mutant strains provided evidence for the existence in the plasma membrane of a carrier specific for fructose. The transport ofd-fructose in the mutant exhibited saturation kinetics up to 1 mmol/Ld-fructose; at higher concentrations the rate ofd-fructose uptake decreased. In the wild-type strain biphasicd-fructose uptake kinetics were observed; the low-affinity component was not found in the mutant, but the high-affinity transport system persisted. During the exponential phase of growth (ond-glucose) the high-affinityd-fructose system was repressed in the wild-type strain. Mutual competition betweend-fructose andd-glucose as well as the pH dependence of transport of the two hexoses further supported the following conclusion: In the wild-type strain,d-fructose is taken up both by the specific fructose carrier (K _T=0.22 mmol/L) and the glucose carrier (K _T=9.13 mmol/L). The former does not translocated-glucose, the latter is damaged by the mutation. Finally H⁺ co-transport and plasma membrane depolarization induced by the onset ofd-fructose transport indicated that the fructose carrier is an H⁺ symporter.     

Genetic mapping of the polycystic kidney gene,pcy, on mouse chromosome 9

The murine polycystic kidney disease gene,pcy, is an autosomal recessive trait located on chromosome 9. To determine the genetic locus ofpcy, 222 intraspecific backcross mice were obtained by mating C57BL/6FG-pcy andMus molossinus. Restriction fragment length polymorphism analysis of 70 of the 222 backcross progeny showed thatpcy, dilute coat color (d), and cholecystokinin (Cck) were located in the orderd—pcy—Cck from the centromere. Simple sequence repeat length polymorphism analysis of DNA of all 222 backcross mice was carried out using four markers which were located near the central regions ofd andCck. One and eight recombinations were detected betweenD9Mit24 andpcy and betweenD9Mit16 andpcy, respectively. However, no recombinant was observed amongpcy, D9Mit14, andD9Mit148. These findings strongly suggest thatD9Mit14 andD9Mit148 are located near thepcy gene and are good markers for chromosomal walking to this gene.     

Molecular mapping of<Emphasis Type="Italic"> Fusarium oxysporum</Emphasis> f. sp.<Emphasis Type="Italic"> ciceris</Emphasis> race 3 resistance gene in chickpea

Sequence-tagged microsatellite site (STMS) and sequence-tagged site (STS) markers linked closely to Fusarium oxysporum f. sp. ciceris race 3 resistance gene in chickpea were identified, and linkage between three wilt resistance genes was elucidated. The resistance to race 3 in chickpea germplasm accession WR-315 was inherited as a single gene, designated foc-3, in 100 F₇ recombinant inbred lines derived from the cross of WR-315 (resistant) × C-104 (susceptible). The foc-3 gene was mapped 0.6 cM from STMS markers TA96 and TA27 and STS marker CS27A. Another STMS marker, TA194, at 14.3 cM, flanked the gene on the other side. Linkage between foc-3 and two other chickpea wilt resistance genes, foc-1 (syn. h ₁ ) and foc-4, was established. foc-3 was mapped 9.8 cM from foc-1 and 8.7 cM from foc-4, whereas foc-1 and foc-4 are closely linked at 1.1 cM. The identification of closely linked markers to resistance genes will facilitate marker-assisted selection for introgression of the race 3 resistance gene to susceptible chickpea lines.Communicated by H.C. Becker     

Mapping of QTLs conferring extremely early heading in rice (Oryza sativa L.)

Two genes related to extremely early heading were identified in populations derived from crosses between Hoshinoyume, a variety adapted to the northernmost limit of rice cultivation (Hokkaido), and Nipponbare, a variety adapted to the temperate region of Japan. The segregations for heading date clearly revealed that a two-gene model determined the extremely early heading in the F₂ and BC₁F₁ populations under natural field conditions in Hokkaido. Using molecular markers corresponding to ten known quantitative trait loci (QTLs) for heading date, we carried out QTL analysis in the BC₁F₁ population and detected two QTLs, qDTH-7-1 and qDTH-7-2, both on chromosome 7, and observed epistatic interaction between them. We conclude that the recessive alleles of these two genes contribute to extremely early heading for the adaptation to Hokkaido environment and to stable rice production in Hokkaido. The relationships between the two QTLs identified in this study and known QTLs are discussed.     

Inheritance of supernodulation in soybean and estimation of the genetically effective cell number

Summary Provided the nature of inheritance is known, the frequency of homozygous mutant plants in individual M₂ families (derived from M₁ seed) can be used to estimate the genetically effective cell number (GECN). Segregation ratios in M₃ families derived from M₂ wild-type plants indicated that the supernodulation characters nts382, nts1007 and nts183 are inherited as Mendelian recessives. The nature of inheritance was also known or confirmed to be recessive by crossing the wild type to these and several other mutants derived from the same population of M₂ families. Subsequently, using the frequency of mutant plants in individual M₂ families, the GECN for soybean was calculated to be approximately two.     

A function describing all-sized trunk diameter distribution in warm-temperate rain forests

A simple relation (v-lnB) (u-lnx)=c was recognized betweenx as dbh (or individual basal area) andB as the cumulative basal area abovex, for various stands of warm-temperate rain forests of Yakushima Island, southern Japan (v, u andc, parameters). The model parameters explained a difference in the pattern of stand development between secondary succession after clear-felling and gap regeneration within primary forests.     

Studies of dotted,a regulatory element in maize

Summary Dotted (Dt) is the regulatory element of a two-unit controlling system in maize. Dt causes the inherited change from the recessive a ₁ (colorless) to its dominant allele, A ₁ (anthocyanin production), during the development of the stalk, leaves, and endosperm. The mutation events are observed as sectors of color in an anthocyaninless background.One of the most puzzling, but perhaps significant, aspects of controlling elements in maize is that they originate in conjunction with chromosome or chromatid breaks. This fact invokes a requirement that either an existing regulatory mechanism is disturbed by the breakage or that a foreign element is incorporated before fusion of the broken chromatids.Experimental crosses were made between Dt tester stocks and a pollen parent, a large proportion of whose chromosomes 9 were undergoing the chromatid type of bridge-breakage-fusion cycle. New Dt's were induced in endosperm sectors of 250 of 154,422 kernels tested (1/600); among these, two germinal Dt's (Dt ^crown ₄ and Dt ₅) were recovered, presumably due to chromatid breaks during meiosis or the first microspore division. Dt ₅ produces a mutation pattern very similar to the original Dt ₁ and is located 0.33 crossover units away from the yg ₂ locus. This is close to the known location of Dt ₁ (7 crossover units distal to the yg ₂ locus) and is suggestive of a specific site for Dt inductive breaks. Dt ^crown ₄, on the other hand, is inherited independently of the yg ₂ locus and does not support this contention. Dt ^crown ₄ represents a new state causing a high concentration of fine dots in the crown of the kernel, with little or no dotting at the base.The phase variation of Dt ^crown ₄ is discussed together with the tissue-dependent expression of Dt ^in-ac ₁ (Dotted, inactive-active). Dt ^in-ac ₁ is a new state of Dt ₁ and shows inactive (no a ₁ to A ₁ mutations) and active (a ₁ to A ₁ mutations) phases in the endosperm, whereas it is only in the active phase in the diploid scutellum. The observed phase variation was shown to be a property of the regulatory elements, Dt, responding to differences in the cellular environment.In appreciation of his help and guidance, I dedicate this article to Professor Marcus M. Rhoades on his birthday.Journal Paper No. J-7454 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1880.     

Drought acclimation of two deciduous tree species of different layers in a temperate forest canopy

Water-use strategies of Populus tremula and Tilia cordata, and the role of abscisic acid in these strategies, were analysed. P. tremula dominated in the overstorey and T. cordata in the lower layer of the tree canopy of the temperate deciduous forest canopy. Shoot water potential (), bulk-leaf abscisic acid concentration ([ABA]_leaf), abscisic acid concentration in xylem sap ([ABA]_xyl), and rate of stomatal closure following the supply of exogenous ABA (v) decreased acropetally through the whole tree canopy, and foliar water content per area (w), concentration of the leaf osmoticum (c), maximum leaf-specific hydraulic conductance of shoot (L), stomatal conductance (g_s), and the threshold dose per leaf area of the exogenous ABA (d_a) required to reduce stomatal conductance increased acropetally through the tree canopy (from the base of the foliage of T. cordata to the top of the foliage of P. tremula) in non-stressed trees. The threshold dose per leaf dry mass of the exogenous ABA (d_w) required to reduce stomatal conductance, was similar through the tree canopy. After a drought period (3 weeks), the , w, L, g_s, d_a and d_w had decreased, and c and v had increased in both species. Yet, the effect of the drought period was more pronounced on L, g_s, d_a, d_w and v in T. cordata, and on , w and c in P. tremula. It was concluded that the water use of the species of the lower canopy layer—T. cordata, is more conservative than that of the species of the overstorey, P. tremula. [ABA]_leaf had not been significantly changed in these trees, and [ABA]_xyl had increased during the drought period only in P. tremula. The relations between [ABA]_leaf, [ABA]_xyl and the stomatal conductance, the osmotic adjustment and the shoot hydraulic conductance are also discussed.     

A High-Resolution Genetic Map of the Familial Mediterranean Fever Candidate Region Allows Identification of Haplotype-Sharing among Ethnic Groups

Familial Mediterranean fever (FMF) is a recessive disorder of inflammation caused by mutations in a gene (designatedMEFV) on chromosome 16p13.3. We have recently constructed a 1-Mb cosmid contig that includes the FMF critical region. Here we show genotype data for 12 markers from our physical map, including 5 newly identified microsatellites, in FMF families. Intrafamilial recombinations placedMEFVin the ∼285 kb betweenD16S468/D16S3070andD16S3376.We observed significant linkage disequilibrium in the North African Jewish population, and historical recombinants in the founder haplotype placedMEFVbetweenD16S3082andD16S3373(∼200 kb). In smaller panels of Iraqi Jewish, Arab, and Armenian families, there were significant allelic associations only forD16S3370andD16S2617among the Armenians. A sizable minority of Iraqi Jewish and Armenian carrier chromosomes appeared to be derived from the North African Jewish ancestral haplotype. We observed a unique FMF haplotype common to Iraqi Jews, Arabs, and Armenians and two other haplotypes restricted to either the Iraqi Jewish or the Armenian population. These data support the view that a few major mutations account for a large percentage of the cases of FMF and suggest that some of these mutations arose before the affected Middle Eastern populations diverged from one another.     

RFLP mapping of the genes controlling hybrid breakdown in rice (Oryza sativa L.)

 Complementary recessive genes hwd1 and hwd2 controlling hybrid breakdown (weakness of F₂ and later generations) were mapped in rice using RFLP markers. These genes produce a plant that is shorter and has fewer tillers than normal plants when the two loci have only one or no dominant allele at both loci. A cultivar with two dominant alleles at the hwd1 locus and a cultivar with two dominant alleles at the hwd2 locus were crossed with a double recessive tester line. Linkage analysis was carried out for each gene independently in two F₂ populations derived from these crosses. hwd1 was mapped on the distal region of rice genetic linkage map for chromosome 10, flanked by RFLP markers C701 and R2309 at a distance of 0.9 centiMorgans (cM) and 0.6 cM, respectively. hwd2 was mapped in the central region of rice genetic linkage map for chromosome 7, tightly linked with 4 RFLP markers without detectable recombination. The usefulness of RFLP mapping and map information for the genes controlling reproductive barriers are discussed in the context of breeding using diverse rice germplasm, especially gene introduction by marker-aided selection.     

Nomenclature of the bacteriochlorophyllsc,d, ande

A system for nomenclature of the various homologues of the bacteriochlorophyllsc(1),d(2), ande(3) is presented.     

Macrophyte depth limits in North Island (New Zealand) lakes of differing clarity

The seasonal variation in water clarity, as indicated by the attenuation coefficient for photosynthetically active radiation, K _d (m^-1), was determined by monthly measurements for a year in 9 North Island, New Zealand lakes. K _d varied by a factor of 2 to 3 in 8 of the lakes, and a factor of 5 in one. Annual mean K _d (symbol% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\] _d) varied by a factor of approximately 15 between lakes. The maximum depth of water colonized by macrophytes (z _c)was also determined. Values of z _c were in the range 1.5–12.5 m. The relationship z _c =4.34/% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4saaaa!36BD!\[K\]_d accounted for most (93 percent) of the variability in z _c , indicating that average annual clarity was probably a useful predictor of z _c in lakes in this region. The values of z _c in these North Island lakes were generally greater than values calculated using previously published empirical relationships derived for northern hemisphere groups of lakes. The extent to which these relationships underestimated z _c in the North Island lakes was broadly related to latitude. Estimated average irradiance at z _c in each lake was similar to compensation point irradiances reported previously for freshwater macrophytes.