Susceptibility to db gene and streptozotocin-induced diabetes in C57BL mice: control by gender-associated,MHC-unlinked traits

H-2 haplotype differences distinguish the related C57BL/KsJ (BKs) and C57BL/6J (B6) inbred strains. BKs mice are more susceptible to diabetes induction by a recessive obesity gene, diabetes (db), or by multi-dose streptozotocin (MSZ) administration. The purpose of this study was to evaluate whether the H-2 differences were the important genetic background modifiers determining inbred strain susceptibility or resistance to these diabetogenic stresses. Diabetes susceptibility of BKs.B6-H-2 ^b congenic mice was compared with that of the parental BKs and B6 stocks. In addition, diabetes severity was studied in (B6 × BKs)F₁ and F₂ db/db mice and an H-2 segregation analysis was performed. BKs susceptibility genes expressed in a dominant fashion in the F₁ generation, and were transmitted to F₂ db/db males without apparent segregation. No association between H-2 ^b haplotype and B6-type diabetes resistance was found in response to either the db mutation or to MSZ. Insulitis, associated with development of hyperglycemia in BKs males, also occurred in the H-2 ^b congenic stock. However, an apparent interaction between H-2 ^b haplotype, the db mutation (on chromosome 4), and male gender (Y chromosome?) was indicated by a segregation ratio distortion in recovery of this genotype. A more moderate diabetes in some F₂ db/db females suggested that non-MHC-linked genes controlling sex steroid metabolism were the important determinants of diabetogenic sensitivities in the C57BL stocks. In support of the latter, strain differences were demonstrated in activity levels of steroid sulfatase, which is regulated by a sex-linked gene likely expressed on both the X and Y chromosome, and which may control tissue levels of active androgens and estrogens. We show that the diabetes-susceptible F₁ hybrids exhibit the higher activity associated with the BKs strain.     

Characterization of mitochondrial bioenergetic functions between two forms of Leishmania donovani – a comparative analysis

Leishmaniasis is a growing health problem in many parts of the world partly due to drug resistance of the parasite. This study reports on the fisibility of studying mitochondrial properties of two forms of wild-type L. donovani through the use of selective inhibitors. Amastigote forms of L. donovani exhibited a wide range of sensitivities to these inhibitors. Mitochondrial complex II inhibitor thenoyltrifluoroacetone and F_oF₁-ATP synthase inhibitors oligomycin and dicyclohexylcarbodiimide were refractory to growth inhibition of amastigote forms, whereas they strongly inhibited the growth of promastigote forms. This result indicated that complex II and F_oF₁-ATP synthase were not functional in amastigote forms suggesting the presence of attenuated oxidative phosphorylation in the mitochondria of amastigote forms. In contrast, mitochondrial complex I inhibitor rotenone and complex III inhibitor antimycin A inhibited cellular multiplication and substrate level phosphorylation in amastigote forms, suggesting the role of complex I and complex III for the survival of amastigote forms. Further we studied the mitochondrial activities of both forms by measuring oxygen consumption and ATP production. In amastigote form, substantial ATP formation by substrate level phosphorylation was observed in NADPH-fumarate, NADH-fumarate, NADPH-pyruvate and NADH-pyruvate redox couples. None of the redox couple generated ATP formation was inhibited by F_oF₁-ATP synthase inhibitor oligomycin. Therefore, we may conclude that there are significant differences between these two forms of L. donovani in respect of mitochondrial bioenergetics. Our results demonstrated bioenergetic disfunction of amastigote mitochondria. Therefore, these alterations of metabolic functions might be a potential chemotherapeutic target.     

Population genetics of Drosophila ananassae: inversion polymorphism and body size in Indian geographical populations

Twelve Indian natural populations of Drosophila ananassae, a cosmopolitan and domestic species, were sampled and laboratory populations (mass cultures) were established from naturally impregnated females. These populations were maintained in the laboratory for some generations and were analysed chromosomally to know the frequency of different inversions. The chromosomal analysis revealed the presence of three cosmopolitan inversions. The data on the whole show that there are significant differences in the frequencies of different chromosome arrangements in these populations. Body size (wing length and thorax length) was measured in both sexes (50 females and 50 males), in all the 12 geographical populations of D. ananassae. There are statistically significant differences in wing length as well as in thorax length of both sexes among different geographical populations. Five geographical strains were crossed reciprocally and body size (wing length and thorax length) was measured in F₁ and F₂ progeny. The comparison of body size (both traits) between mid‐parent, F₁ and F₂ shows that there is an increase in body size in F₁ and F₂ progeny as compared with parents. Thus, there is no break down of heterosis in F₂, which suggests absence of coadaptation in geographical populations of D. ananassae. Scaling test statistical analysis showed additive, dominance and epistatic effects in certain crosses involving geographical strains of D. ananassae. Correlation between chromosome arrangement frequency and body size has also been tested and significant negative correlation has been found between 2L – ST chromosome arrangement and male thorax.     

The origin ofMentha X gracilis (Lamiaceae). I. Chromosome numbers,Fertility, and three morphological characters

Employing nine clones ofMentha arvensis and four clones ofM. spicata, 932 F, hybrids were synthesized and compared to 20 clones ofM. x gracilis. Two clones ofM. x gracilis with 60 somatic chromosomes were matched to a selected F₁ hybrid. The other 18 clones ofM. x gracilis had somatic chromosome numbers of 60, 72, 84, and 96, and while these chromosome numbers appeared in the F₁ progeny, morphological matches correlated with their correct chromosome numbers were not synthesized. The range of pollen and seed fertility, as well as the inheritance of male-sterility, leaf pubescence, and crispness, indicates that no one character can be used to identifyM. x gracilis, but all characters can be explained fromM. arvensis x M. spicata.     

Chromosome aberrations caused by the effect of ultrasound in the meristematic cells ofvicia faba

In our present work the formation of chromosome aberrations has been studied in dependence on the tima interval between sonication and fixation of the primary root tips of Vicia faba. Maximum occurrence of aberrations was recorded immediately after sonication. The results of our experiments pointed to the fact that the frequency of the induced changes was independent on the sonic waves intensity within the range of 0-2—3-0 W/cm² and on ultrasond treatment duration within the range of 1—20 min. Studies of the distribution of chromosome abnormalities caused by ultrasound between the large and small chromosomes of theVicia faba meristematic cells in various time intervals showed that the frequency of the aberrations in both chromosome groups was proportional to its total metaphase lengths. Analysis of the type of aberrations observed in various time intervals after sonication indicated the simultaneous formation of chromosome and chromatide abnormalities.     

The genetic system controlling recombination in the silkworm

The nature of recombination modifiers was investigated in Bombyx mori lines selected for high (H) and low (L) recombination rates between the p^S and Y loci in chromosome 2. Since the mean recombination rates for the H x L and L x H F₁ crosses were approximately intermediate between those of high and low lines, the cytoplasmic maternal effect and difference in the activity of recombination modifiers between marked and unmarked second chromosomes were not detected. The H x (L x H), H x (H x L), L x (L x H) and L x (H x L) backcrosses indicated the presence of additive and dominance effects of marked and unmarked second chromosomes and the remaining chromosomes.——Recombination rates between the p^S and Y loci in chromosome 2 and half-nonrecombination rates between the pe and re loci in chromosome 5 of high and low lines indicated that these recombination modifiers caused changes in the recombination frequency between p^S and Y in chromosome 2, but not between pe and re in chromosome 5.——There were no differences in viability between individuals having the second chromosomes of the recombinant types [p^S +, p^Y (H); p^S +, + Y (L)] and those of the nonrecombinant types [p^S Y, p + (H); p^S Y, + + (L)] in both high and low lines. Mean recombination rates measured in cis [p^S Y/p + (H); p^S Y/+ + (L)] and trans [p^S +/p Y (H); p^S +/+ Y (L)] males were the same in the high but not in the low line. No segregation of a single recombination modifier was indicated by the distribution of recombination rates measured in trans males [p^S +/p Y (H); p^S +/+ Y (L)] of high and low lines. Accordingly, the recombination modifiers distributed on chromosome 2 in the heterozygous condition were not gross chromosomal aberrations, but polygenic factors in the low line.     

Combined use of bulked segregant analysis and microarrays reveals SNP markers pinpointing a major QTL for resistance to Phytophthora capsici in pepper

Key message

Bulked segregant analysis (BSA) using Affymetrix GeneChips revealed candidate genes underlying the major QTL for Phytophthora capsici resistance in Capsicum . Using the candidate genes, reliable markers for Phytophthora resistance were developed and validated.

Abstract

Phytophthora capsici L. is one of the most destructive pathogens of pepper (Capsicum spp.). Resistance of pepper against P. capsici is controlled by quantitative trait loci (QTL), including a major QTL on chromosome 5 that is the predominant contributor to resistance. Here, to maximize the effect of this QTL and study its underlying genes, an F₂ population and recombinant inbred lines were inoculated with P. capsici strain JHAI1-7 zoospores at a low concentration (3 × 10³/mL). Resistance phenotype segregation ratios for the populations fit a 3:1 and 1:1 (resistant:susceptible) segregation model, respectively, consistent with a single dominant gene model. Bulked segregant analysis (BSA) using Affymetrix GeneChips revealed a single position polymorphism (SPP) marker mapping to the major QTL. When this SPP marker (Phyto5SAR) together with other SNP markers located on chromosome 5 was used to confirm the position of the major QTL, Phyto5SAR showed the highest LOD value at the QTL. A scaffold sequence (scaffold194) containing Phyto5SAR was identified from the C. annuum genome database. The scaffold contained two putative NBS-LRR genes and one SAR 8.2A gene as candidates for contributing to P. capsici resistance. Markers linked to these genes were developed and validated by testing 100 F₁ commercial cultivars. Among the markers, Phyto5NBS1 showed about 90 % accuracy in predicting resistance phenotypes to a low-virulence P. capsici isolate. These results suggest that Phyto5NBS1 is a reliable marker for P. capsici resistance and can be used for identification of a gene(s) underlying the major QTL on chromosome 5.     

Combined Effects of Lead and Acid Rain on Photosynthesis in Soybean Seedlings

To explore how lead (Pb) and acid rain simultaneously affect plants, the combined effects of Pb and acid rain on the chlorophyll content, chlorophyll fluorescence reaction, Hill reaction rate, and Mg²⁺-ATPase activity in soybean seedlings were investigated. The results indicated that, when soybean seedlings were treated with Pb or acid rain alone, the chlorophyll content, Hill reaction rate, Mg²⁺-ATPase activity, and maximal photochemical efficiency (F _v/F _m) were decreased, while the initial fluorescence (F ₀) and maximum quantum yield (Y) were increased, compared with those of the control. The combined treatment with Pb and acid rain decreased the chlorophyll content, Hill reaction rate, Mg²⁺-ATPase activity, F _v/F _m, and Y and increased F ₀ in soybean seedlings. Under the combined treatment with Pb and acid rain, the two factors showed additive effects on the chlorophyll content in soybean seedlings and exhibited antagonistic effects on the Hill reaction rate. Under the combined treatment with high-concentration Pb and acid rain, the two factors exhibited synergistic effects on the Mg²⁺-ATPase activity, F ₀, F _v/F _m, as well as Y. In summary, the inhibition of the photosynthetic process is an important physiological basis for the simultaneous actions of Pb and acid rain in soybean seedlings.     

Cytogenetics of ticks (Acari: Ixodoidea)

Chromosomes and sex determination of 9 species of Haemaphysalis assigned to 4 subgenera are described. H. (tAlloceraea) kitaokai possesses an XX∶XO sex chromosome system with 18 autosomes plus XX in females; 18 plus X in males. H. (Kaiseriana) hystricis has 18 +XX and 18 + XY in females and males, respectively, in most specimens, but a supernumerary chromosome is present in some individuals. A supernumerary chromosome was also observed in 1 male H. (Aborphysalis) formosensis. These two species are the second and third species of ticks reported to have supernumerary chromosomes. H. formosensis, H. (Kaiseriana) bispinosa, H. (Haemaphysalis) campanulata, H. (H.) flava, H. (H.) megaspinosa, H. (H.) japonica, and H. (H.) pentalagi possess 20 autosomes plus 2 sex chromosomes in females and 20+1 sex chromosomes in males. Phylogenetic relationships within the genus Haemaphysalis are briefly discussed.     

Reproductive relationships between annual species ofCalendula (Compositae)

Breeding experiments were carried out inCalendula species. In the annuals, which are selfers, rarely some outcrossing was observed only in the most peripheral flowers. In experimental crosses fruit was produced in all combinations. Fertile F₁ and F₂ hybrids could be grown from crosses between parents with similar chromosome numbers:C. palaestina ×C. pachysperma and crosses of different morphological forms ofC. arvensis. In crosses of species with different chromosome numbers at least partly fertile F₁ hybrids were obtained fromC. tripterocarpa ×C. stellata andC. tripterocarpa ×C. arvensis and crosses of the latter withC. palaestina. Fertile F₂ plants were grown from the combination ofC. arvensis ×C. tripterocarpa. Considering this information and previously obtained data, a scheme is proposed for explaining speciation in the genusCalendula.     

Induced Homoeologous Pairing for Transfer of Useful Variability for High Grain Fe and Zn from <Emphasis Type="Italic">Aegilops kotschyi</Emphasis> into Wheat

Biofortification of bread wheat by the transfer of useful variability of high grain Fe and Zn from Aegilops kotschyi through induced homoeologous pairing is the most feasible approach to alleviate micronutrient malnutrition worldwide. Deficiency of chromosome 5B in interspecific hybrids allows homoeologous pairing and recombination of chromosomes of wheat with those of the related species. The interspecific hybrid plants without 5B chromosome showed much higher chromosome pairing than did the plants with 5B. The F₁ plants without 5B chromosome were selected and repeatedly backcrossed with wheat cultivar PBW343. The chromosome number of BC₂F₁ plants ranged from 43 to 60 with several univalents and multivalents. Molecular markers and GISH analysis confirmed the introgression of U/S chromosomes of Ae. kotschyi and their fragments in wheat. The BC₂F₂ plants showed up to 125 % increase in Fe and 158 % increase in Zn compared to PBW343 with Lr24 and Yr36. Induced homoeologous pairing in the absence of 5B was found to be an effective approach for transfer of useful variability for enhanced grain Fe and Zn content for biofortification of wheat for high grain micronutrient content.     

Use of synteny to identify candidate genes underlying QTL controlling stomatal traits in faba bean (Vicia faba L.)

Key message

We have identified QTLs for stomatal characteristics on chromosome II of faba bean by applying SNPs derived from M. truncatula , and have identified candidate genes within these QTLs using synteny between the two species.

Abstract

Faba bean (Vicia faba L.) is a valuable food and feed crop worldwide, but drought often limits its production, and its genome is large and poorly mapped. No information is available on the effects of genomic regions and genes on drought adaptation characters such as stomatal characteristics in this species, but the synteny between the sequenced model legume, Medicago truncatula, and faba bean can be used to identify candidate genes. A mapping population of 211 F₅ recombinant inbred lines (Mélodie/2 × ILB 938/2) were phenotyped to identify quantitative trait loci (QTL) affecting stomatal morphology and function, along with seed weight, under well-watered conditions in a climate-controlled glasshouse in 2013 and 2014. Canopy temperature (CT) was evaluated in 2013 under water-deficit (CTd). In total, 188 polymorphic single nucleotide polymorphisms (SNPs), developed from M. truncatula genome data, were assigned to nine linkage groups that covered ~928 cM of the faba bean genome with an average inter-marker distance of 5.8 cM. 15 putative QTLs were detected, of which eight (affecting stomatal density, length and conductance and CT) co-located on chromosome II, in the vicinity of a possible candidate gene—a receptor-like protein kinase found in the syntenic interval of M. truncatula chromosome IV. A ribose-phosphate pyrophosphokinase from M. truncatula chromosome V, postulated as a possible candidate gene for the QTL for CTd, was found some distance away in the same chromosome. These results demonstrate that genomic information from M. truncatula can successfully be translated to the faba bean genome.     

A T-cell antigen system of chickens: Ly-4 and Marek's disease

A search was made for lymphocyte antigens associated with resistance or susceptibility to the T-cell lymphoma induced by the herpes virus of Marek's disease (MD), the experimental model for Burkitt's lymphoma of humans. Antisera were produced by reciprocal immunization with whole blood between an MD-resistant and susceptible line of chickens compatible at the major histocompatibility complex (MHC), and were tested against lymphocytes of both lines. The lymphocytes were not agglutinated, immobilized, or lysed, but their ability to evoke graft-versus-host (GVH) splenomegaly was reduced. This inhibitory activity was line-specific, and these sera had a maximum limiting effect on GVH splenomegaly at a dilution of 1/50 and a minimum at 1/800 dilution. A test based on the differential limitation of GVH splenomegaly by a pair of alloantisera was used to identify the antigens in F₁ and F₂ generations. The segregation results established a locus,Ly-4, with two codominant alleles,Ly- 4^a andLy-4 ^b .Ly-4 is distinct from theA, B, orC blood group loci and from theBu-1 locus determining B-cell antigens, but may be linked to theTh-1 locus determining T-cell antigens (recombination frequency of 32 percent). Tentative evidence was obtained from comparisons of homozygous F₂ and F₃ progeny for association of theLy-4 allele characteristic of the susceptible line with increased incidence of MD.     

Esterase-16 (Es-16): Characterization,polymorphism, and linkage to chromosome 3 of a kidney esterase locus of the house mouse

A polymorphism for an isozyme of a presumed arylesterase, esterase-16 (EC 3.1.1.2), has been detected in kidney, heart, and spleen of the house mouse, Mus musculus, by means of isoelectric focusing and by disc electrophoresis. Three phenotypes can be distinguished: the ES-16A phenotype (IEP 5.9) was found in C57BL/10Sn and many other laboratory inbred strains; the ES-16B phenotype (IEP 6.1) was found in M. m. molossinus; and the ES-16C phenotype (IEP 5.9; very weak activity) was found in Peru-Coppock. Esterase-16 is strongly inhibited by 10^?3 m p-chloromercuribenzoate, but not by 2·10^?4 m bis-p-nitrophenyl phosphate or by 10^?3 m Diamox. It stains well with indoxyl acetate and other indigogenic substrates but only weakly with α-naphthyl acetate. Esterase-16 is completely insoluble in water. It is apparently governed by a structural gene locus, Es-16, with three alleles, Es-16 ^a , Es-16^b, and Es-16 ^c, respectively. Es-16 is closely linked to Car-1 and Car-2 on chromosome 3. Typing of 94 animals of the backcross (C57BL/10Sn × M. m. mol.) F₁ × M. m. mol. revealed a recombination frequency of 8.51±2.9%.     

Variability of skull and dental characteristics in Mus spicilegus from the northern border of its distributional range

Results of morphometric analysis of the mound-building mouse (Mus spicilegus) evaluated in this study originate from field trapping in the eastern part of Slovakia during the years 2003–2008. Twenty-four cranial and dental variables and the zygomatic index (A/B) of 80 skulls (43 males, 37 females) were measured and evaluated with respect to the sex of the mice. Despite the fact that the overlap of skull measurements in adult males and females was high, sexual dimorphism was confirmed for several skull and dental traits. On average, the values for adult females of M. spicilegus were higher than males, with the exception of dental traits and the zygomatic index. Significant differences between adult males and females were found for the mean values of ten skull and dental parameters (LB, LCb, FL, LD, LMd, LaZ, LM¹, LM₁, LaM¹ and LaM₁). The values for the zygomatic index (A/B) overlapped between both sexes, but the higher average values in adult males were statistically significant. The results showed that the variability of the species confirmed in this paper was probably caused only at the regional level and did not differ from the findings reported by several authors for species from neighboring countries.     

Influence of exogenous DNA on Ypenyl-treated chromosomes ofVicia faba L.

This paper is a study of the effect of exogenous DNA of different genetic origins on the repair of meristematic cells of primary roots ofVicia faba, damaged by 24 hour treatment with 0·01mm solution of Ypenyl. Both kinds of DNA,i.e. isologous and heterologous, stimulated cell proliferation which was decreased by the action of the radiomimetic and influenced both dynamics of production of chromosome aberrations and the interchromosomal distribution of induced damage. While heterologous DNA increased the frequency of aberrations after all recovery periods studied, isologous DNA significantly decreased the number of chromosomal aberrations. Heterologous DNA increased at the same time the relative number of breaks in the group of small chromosomes, while by the action of isologous DNA the number of aberrations related to this group of chromosomes was relatively decreased.