Combining Ability of Common Winter Wheat Cultivars

Abstract TSENOV, N. and E. TSENOVA, 2011. Combining ability of common winter wheat cultivars (Triticum aestivum L.) by date to heading and date to physiological maturity. Bulg. J. Agric. Sci., This investigation was carried out with a view of evaluating the combining ability and the heritability regularities of a group of wheat cultivars which differed significantly by their date to heading (DH) and date to physiological maturity (DPM). Six common winter wheat cultivars were combined in a complete diallele crossing scheme. The two traits were represented as number of days from 1 st January to the respective date for each of them. During three successive years, the early F 1 and F 2 hybrid generations were analyzed. They were grown in a randomized design, the distance between the rows being 20 cm and the distance between the plants in each row -10 cm. Each cultivar was evaluated for combining ability and the breeding value of each combination was assessed for the above two traits. The combining ability and the genetic parameters were calculated using the program Dial 98. Lack of reciprocal effect was established although the mother component strongly affected the phenotypic expression of the two traits. There were significant variations between the investigated cultivars in the expression of the two traits within 5-7 days. The values of GCA were predominant as a rule over the values of SCA in the variation analysis performed on the entire crossing scheme. This was evidence for some dominance of the genes with additive effect of the factors determining the two traits. GCA of each cultivar was directly related to the expression of the two traits, the correlation being as high as 0.95. The heritability of the two traits was analogous and resulted from complex combinations of genes with different effects (additive or dominant). The higher the difference between the parental cultivars in a combination by the two traits, the higher the inherited DH and DPM values were. The regularities in the genetic control and the combining ability of the investigated cultivars by DH were completely analogous for the trait DPM, as well. This means that earliness could be easily evaluated by DH. Cultivars Pliska, Vratsa and Obriy had high combining ability towards earlier dates to heading and maturity. Cultivar Pryaspa had the latest dates in the diallele crossing scheme, but its breeding value implied successful breeding of earliness in combination with high productivity

TNF-dependent regulation and activation of innate immune cells are essential for host protection against cerebral tuberculosis

BACKGROUND: Tuberculosis (TB) affects one third of the global population, and TB of the central nervous system (CNS-TB) is the most severe form of tuberculosis which often associates with high mortality. The pro-inflammatory cytokine tumour necrosis factor (TNF) plays a critical role in the initial and long-term host immune protection against Mycobacterium tuberculosis (M. tuberculosis) which involves the activation of innate immune cells and structure maintenance of granulomas. However, the contribution of TNF, in particular neuron-derived TNF, in the control of cerebral M. tuberculosis infection and its protective immune responses in the CNS were not clear. METHODS: We generated neuron-specific TNF-deficient (NsTNF / ) mice and compared outcomes of disease against TNF f/f control and global TNF / mice. Mycobacterial burden in brains, lungs and spleens were compared, and cerebral pathology and cellular contributions analysed by microscopy and flow cytometry after M. tuberculosis infection. Activation of innate immune cells was measured by flow cytometry and cell function assessed by cytokine and chemokine quantification using enzyme-linked immunosorbent assay (ELISA). RESULTS: Intracerebral M. tuberculosis infection of TNF / mice rendered animals highly susceptible, accompanied by uncontrolled bacilli replication and eventual mortality. In contrast, NsTNF / mice were resistant to infection and presented with a phenotype similar to that in TNF f/f control mice. Impaired immunity in TNF / mice was associated with altered cytokine and chemokine synthesis in the brain and characterised by a reduced number of activated innate immune cells. Brain pathology reflected enhanced inflammation dominated by neutrophil influx. CONCLUSION: Our data show that neuron-derived TNF has a limited role in immune responses, but overall TNF production is necessary for protective immunity against CNS-TB

Mycobacterium tuberculosis Lineage Influences Innate Immune Response and Virulence and Is Associated with Distinct Cell Envelope Lipid Profiles

The six major genetic lineages of Mycobacterium tuberculosis are strongly associated with specific geographical regions, but their relevance to bacterial virulence and the clinical consequences of infection are unclear. Previously, we found that in Vietnam, East Asian/Beijing and Indo-Oceanic strains were significantly more likely to cause disseminated tuberculosis with meningitis than those from the Euro-American lineage. To investigate this observation we characterised 7 East Asian/Beijing, 5 Indo-Oceanic and 6 Euro-American Vietnamese strains in bone-marrow-derived macrophages, dendritic cells and mice. East Asian/Beijing and Indo-Oceanic strains induced significantly more TNF-α and IL-1β from macrophages than the Euro-American strains, and East Asian/Beijing strains were detectable earlier in the blood of infected mice and grew faster in the lungs. We hypothesised that these differences were induced by lineage-specific variation in cell envelope lipids. Whole lipid extracts from East Asian/Beijing and Indo-Oceanic strains induced higher concentrations of TNF-α from macrophages than Euro-American lipids. The lipid extracts were fractionated and compared by thin layer chromatography to reveal a distinct pattern of lineage-associated profiles. A phthiotriol dimycocerosate was exclusively produced by East Asian/Beijing strains, but not the phenolic glycolipid previously associated with the hyper-virulent phenotype of some isolates of this lineage. All Indo-Oceanic strains produced a unique unidentified lipid, shown to be a phenolphthiocerol dimycocerosate dependent upon an intact pks15/1 for its production. This was described by Goren as the ‘attenuation indictor lipid’ more than 40 years ago, due to its association with less virulent strains from southern India. Mutation of pks15/1 in a representative Indo-Oceanic strain prevented phenolphthiocerol dimycocerosate synthesis, but did not alter macrophage cytokine induction. Our findings suggest that the early interactions between M. tuberculosis and host are determined by the lineage of the infecting strain; but we were unable to show these differences are driven by lineage-specific cell-surface expressed lipids

Phosphodiesterase-4 Inhibition Alters Gene Expression and Improves Isoniazid – Mediated Clearance of Mycobacterium tuberculosis in Rabbit Lungs

Tuberculosis (TB) treatment is hampered by the long duration of antibiotic therapy required to achieve cure. This indolent response has been partly attributed to the ability of subpopulations of less metabolically active Mycobacterium tuberculosis (Mtb) to withstand killing by current anti-TB drugs. We have used immune modulation with a phosphodiesterase-4 (PDE4) inhibitor, CC-3052, that reduces tumor necrosis factor alpha (TNF-α) production by increasing intracellular cAMP in macrophages, to examine the crosstalk between host and pathogen in rabbits with pulmonary TB during treatment with isoniazid (INH). Based on DNA microarray, changes in host gene expression during CC-3052 treatment of Mtb infected rabbits support a link between PDE4 inhibition and specific down-regulation of the innate immune response. The overall pattern of host gene expression in the lungs of infected rabbits treated with CC-3052, compared to untreated rabbits, was similar to that described in vitro in resting Mtb infected macrophages, suggesting suboptimal macrophage activation. These alterations in host immunity were associated with corresponding down-regulation of a number of Mtb genes that have been associated with a metabolic shift towards dormancy. Moreover, treatment with CC-3052 and INH resulted in reduced expression of those genes associated with the bacterial response to INH. Importantly, CC-3052 treatment of infected rabbits was associated with reduced ability of Mtb to withstand INH killing, shown by improved bacillary clearance, from the lungs of co-treated animals compared to rabbits treated with INH alone. The results of our study suggest that changes in Mtb gene expression, in response to changes in the host immune response, can alter the responsiveness of the bacteria to antimicrobial agents. These findings provide a basis for exploring the potential use of adjunctive immune modulation with PDE4 inhibitors to enhance the efficacy of existing anti-TB treatment

Gene action in the inheritance of date to ear emergence and time to physiological maturity in bread wheat crosses (Triticum aestivum L.)

Abstract. The date of ear emergence (DEE) and the date (time) of physiological maturity (TPM), as quantitative indication affect yield and in this respect any information about their genetic nature is important for breeding in climatic anomalies of the country. This study aims to give a detailed analysis of the succession of traits DEE and TPM to gather updated information on the genetic control of contrast by combining traits varieties. We studied six generations originating from 6 hybrid combinations of "early " and "late " with respect to the varieties of both traits. It was determine the type of inheritance and coefficients of heritability. To identify real opportunities for breeding of early forms recurrent combinations with each of the parental varieties are made. Data suggest complex interactions between genes for both traits .An inspection for the presence of epistas by applying the well-known 3-parameter test, is calculated. For additional information components of genetic diversity were calculated. In crosses in which is found non-allelic interaction is applied 6 - parameter model, that explains the specific nature of these interactions on a cross. The combination of varieties with different dates of ear emergence and maturation succession of both traits is partially dominant to the complete domination of the "late" parent. Performing backcross procedure changes significantly in direct proportion to recurrent that in late varieties causes heterosis . At 2 /3 of the combinations studied non-allelic interaction are set at both traits. On the inheritance of every trait share a non-allelic interactions between genes that are specific for each cross and defy generalization. The direction of the inheritance to the later date suggests that the breeding of the early forms is preferable by making recurrent crosses . Earlier of ear emergence date varieties as Enola, Galatea and Obrii should be used in terms of a compromise combination of early ear heading and extending ripening of grain , which is important for obtaining a high yield of grain

The Phenolic Glycolipid of Mycobacterium tuberculosis Differentially Modulates the Early Host Cytokine Response but Does Not in Itself Confer Hypervirulence▿

Mycobacterium tuberculosis possesses a diversity of potential virulence factors including complex branched lipids such as the phenolic glycolipid PGL-tb. PGL-tb expression by the clinical M. tuberculosis isolate HN878 has been associated with a less efficient Th1 response and increased virulence in mice and rabbits. It has been suggested that the W-Beijing family is the only group of M. tuberculosis strains with an intact pks1-15 gene, required for the synthesis of PGL-tb and capable of producing PGL-tb. We have found that some strains with an intact pks1-15 do not produce PGL-tb while others may produce a variant of PGL-tb. We examined the early host cytokine response to infection with these strains in vitro to better understand the effect of PGL-tb synthesis on immune responses. In addition, we generated a PGL-tb-producing H37Rv in order to determine the effect of PGL-tb production on the host immune response during infection by a strain normally devoid of PGL-tb synthesis. We observed that PGL-tb production by clinical M. tuberculosis isolates affected cytokine production differently depending on the background of the strain. Importantly, while ectopic PGL-tb production by H37Rv suppressed the induction of several pro- and anti-inflammatory cytokines in vitro in human monocytes, it did not lead to increased virulence in infected mice and rabbits. Collectively, our data indicate that, while PGL-tb may play a role in the immunogenicity and/or virulence of M. tuberculosis, it probably acts in concert with other bacterial factors which seem to be dependent on the background of the strain

Role of the DinB Homologs Rv1537 and Rv3056 in Mycobacterium tuberculosis▿ †

The environment encountered by Mycobacterium tuberculosis during infection is genotoxic. Most bacteria tolerate DNA damage by engaging specialized DNA polymerases that catalyze translesion synthesis (TLS) across sites of damage. M. tuberculosis possesses two putative members of the DinB class of Y-family DNA polymerases, DinB1 (Rv1537) and DinB2 (Rv3056); however, their role in damage tolerance, mutagenesis, and survival is unknown. Here, both dinB1 and dinB2 are shown to be expressed in vitro in a growth phase-dependent manner, with dinB2 levels 12- to 40-fold higher than those of dinB1. Yeast two-hybrid analyses revealed that DinB1, but not DinB2, interacts with the β-clamp, consistent with its canonical C-terminal β-binding motif. However, knockout of dinB1, dinB2, or both had no effect on the susceptibility of M. tuberculosis to compounds that form N2-dG adducts and alkylating agents. Similarly, deletion of these genes individually or in combination did not affect the rate of spontaneous mutation to rifampin resistance or the spectrum of resistance-conferring rpoB mutations and had no impact on growth or survival in human or mouse macrophages or in mice. Moreover, neither gene conferred a mutator phenotype when expressed ectopically in Mycobacterium smegmatis. The lack of the effect of altering the complements or expression levels of dinB1 and/or dinB2 under conditions predicted to be phenotypically revealing suggests that the DinB homologs from M. tuberculosis do not behave like their counterparts from other organisms