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Maize streak disease (MSD) is the most devastating and destructive disease of maize (Zea mays L.) in sub-Saharan Africa (SSA). Field trials were conducted in the 2014 minor and 2015 major cropping seasons to screen 16 and 17 maize genotypes, respectively, for high yield and resistance to maize streak virus (MSV) infections. The plants were scored for disease severity at 4, 6, 8 and 10 weeks after planting (WAP) based on a 1-5 visual scale (1= No infection and 5= Very severe infection). Polymerase chain reaction (PCR) test was done to detect the presence of MSV in the diseased leaf samples in order to confirm field resistance. Both phenotypic and PCR test revealed that all the maize genotypes tested in the study were infected by MSV. There was a significant varietal effect on the incidence and severity of MSD in both the major and minor seasonal trials. Genotypes 'Abontem','Aburohemaa', 'Akposoe', 'Dapango', 'Dorke', 'Etubi', 'Honampa', 'Mamaba', 'Obatanpa', 'Omankwa' and PAN 12 showed mild disease symptoms during both major and minor cropping seasons. On the other hand, genotypes 'Dormabin', 'Dzinu-Eve', 'Enibi', Keta 60 and PAN 53 exhibited moderate to severe symptoms during the two cropping seasons. Incidence and severity of MSD were significantly higher in the minor season than in the major season, indicating a significant seasonal effect of MSV on the maize genotypes. The yield and yield components were observed to vary significantly among the different maize genotypes and between the cropping seasons with mean yields significantly higher in the major season than in the minor season. Genotypes 'Abontem', 'Aburohemaa', 'Akposoe', 'Dorke', 'Etubi', 'Honampa', 'Omankwa', 'Obatanpa' and PAN 12 (All improved varieties), which exhibited partial resistance to MSV infection gave high seed yields during both seasons. The improved maize genotypes that were high yielding and resistant to MSV infection should be evaluated for uniform yield trials on farmers' fields towards their release as varieties to farmers. Key words: Maize streak virus, Yield losses, Phenotypic, Molecular detection, Polymerase chain reaction, INTRODUCTION Maize (Zea mays L.) is the most widely grown staple food crop in sub-Saharan Africa (SSA), occupying more than 33 million hectares each year [1]. Maize is an excellent [...]

Phylogenetic relationships within marsupials were investigated based on a 20.1-kilobase molecular supermatrix comprising 7 nuclear and 15 mitochondrial genes analyzed using both maximum likelihood and Bayesian approaches and 3 different partitioning strategies. The study revealed that base composition bias in the 3rd codon positions of mitochondrial genes misled even the partitioned maximum-likelihood analyses, whereas Bayesian analyses were less affected. After correcting for base composition bias, monophyly of the currently recognized marsupial orders, of Australidelphia, and of a clade comprising Dasyuromorphia, Notoryctes, and Peramelemorphia, were supported strongly by both Bayesian posterior probabilities and maximum-likelihood bootstrap values. Monophyly of the Australasian marsupials, of Notoryctes + Dasyuromorphia, and of Caenolestes + Australidelphia were less well supported. Within Diprotodontia, Burramyidae + Phalangeridae received relatively strong support. Divergence dates calculated using a Bayesian relaxed molecular clock and multiple age constraints suggested at least 3 independent dispersals of marsupials from North to South America during the Late Cretaceous or early Paleocene. Within the Australasian clade, the macropodine radiation, the divergence of phascogaline and dasyurine dasyurids, and the divergence of peranaeline and peroryctine peramelemorphians all coincided with periods of significant environmental change during the Miocene. An analysis of 'unrepresented basal branch lengths' suggests that the fossil record is particularly poor for didelphids and most groups within the Australasian radiation. Key words: Ameridelphia, Australidelphia, Bayesian analysis, fossil record, marsupials, phylogenetic fuse, phylogeny, relaxed molecular clock, supermatrix

A homogeneous DNA diagnostic assay based on template-directed primer extension detected by fluorescence resonance energy transfer, named template-directed dye-terminator incorporation (TDI) assay, has been developed for mutation detection and high throughput genome analysis. Here, we report the successful application of the TDI assay to detect mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the human leukocyte antigen H (HLA-H) gene, and the receptor tyrosin kinase (RET) protooncogene that are associated with cystic fibrosis, hemochromatosis, and multiple endocrine neoplasia, type 2, respectively. Starting with total human DNA, the samples are amplified by the PCR followed by enzymatic degradation of excess primers and deoxyribonucleoside triphosphates before the primer extension reaction is performed. All these standardized steps are performed in the same tube, and the fluorescence changes are monitored in real time, making it a useful clinical DNA diagnostic method.

A model using Petunia plants bearing chalcone synthase A (chsA) transgenes is presented to illustrate how chsA RNA degradation is likely to be promoted to cause phenotypic cosuppression. It was observed that transgenic plants with purple or purple-white flowers can have high levels of endogene and transgene poly(A)+ chsA RNAs while plants with all-white flowers exhibit significant loss of endogene and transgene poly(A)+ RNAs. The results also indicated that the transgene RNA found in transgenic lines acts solely to trigger the induction of an existing chsA RNA-specific, posttranscriptional control mechanism.

Enzyme assays and nucleic acid manipulation techniques were used to investigate the mobility of yeast mitochondrial group II introns, al1 and al2. The results showed that sense-strand cleavage for al2 occurs mainly through a partial reverse splicing reaction while that for al1 entails complete reverse splicing which results to the insertion of the linear intron RNA into double-stranded DNA. It was also found that al1 homing and reverse splicing is dependent on the EBS1(RNA)/IBS1(DNA) pairing and that target specificity can be altered by compensatory changes in the target site and the donor intron. Homing was documented to proceed via RT-dependent and -independent pathways.

The mechanism involved in the T cell lineage decision was studied using transgenic mice as host systems, supplemented with flow cytometry and polymerase chain reaction-restriction fragment length polymorphism. The results revealed that T cells that are heterozygous for a mutation of the Notch1 gene have a greater tendency to develop as gamma-delta T cells rather than as alpha-beta T cells. A constitutively activated form of Notch gene, on the other hand, stimulates the thymocytes to adopt the alpha-beta T cell fate. Notch, together with the newly formed T cell antigen receptor are thus identified as determinants of T cell lineage decision.

Mutants of Drosophila alpha-adaptin gene were prepared and used to study its role in presynaptic vesicle recycling by clathrin-mediated endocytosis during neural transmission. The results demonstrated that alpha-adaptin is expressed in garland cells, imaginal discs and the central nervous system. Its functional analysis showed that alpha-adaptin plays an important role in the formation of clathrin-coated pits and in the recruitment of dynamin to the endocytic sites in presynaptic terminals.

Molecular biological techniques were performed to characterize Frzb, a soluble Xenopus homolog bearing an amino-terminal Frizzled motif. Frzb was found to be expressed in the Spemann organizer during early gastrulation. Functional assays revealed that Frzb antagonizes Xwnt-8, a ventralizing factor exhibiting an expression pattern complementary to that of Frzb. It was also shown that Frzb inhibits the induction of MyoD. These findings thus indicated that Frzb is involved in axial patterning and it can inhibit inappropriate ventral signaling in developing dorsal tissues.

Oligodeoxynucleotides containing a single dG-N2-3MeE or dA-N6-3MeE were synthesized and used for the quantitative measurement of miscoding specificities of experimental models of estrogen-DNA adducts in terms of base substitution and deletion. The miscoding specificities and their frequencies were found to vary with the type of DNA polymerase used to catalyze the DNA synthesis.

Various cell lines were used to study the occurrence of double-reciprocal crossover which accompany the activity of FLP recombinase. A reaction called recombinase-mediated cassette exchange (RMCE) was induced between two fragments of DNA that are each flanked by identical FLP recognition target (FRT) sites. The results of the experiment confirmed that changing a parent cassette by the transfection of a vector bearing the cassette of choice is feasible. Such finding is a breakthrough for it can be utilized for further studies in molecular genetics, specifically for researches on gene therapy.

Hydroxyl radical (.OH) footprinting was done to compare the interactions of Escherichia coli sigma-s and sigma-70 holoenzymes with the bolAp1 promoter. It was deduced from the high-resolution .OH footprint data that the two holoenzymes are quite similar but not identical in their functions, with sigma-70 exhibiting weaker transcriptional activity. The transcription start sites of the two, however, were found to be the same.

The crystallized structure of the Saccharomyces cerevisiae class I ubiquitin-conjugating enzyme, Ubc7 was solved using molecular replacement techniques. The analysis of the protein revealed that its ubiquitin-accepting cysteine is located between the fourth strand, S4 of the beta-sheet and the second alpha-helix, B. A hypervariable surface region was also identified which is thought to be the position responsible for the enzyme's interaction with different E3 proteins or substrates.

Recombinant HIV-1 protease (PR) mutants, V82F, I84V and V82F/I84V, in the presence of cyclic urea inhibitors DMP450 and DMP323 were used to study the factors that affect HIV-1 resistance to protease inhibitors. Results revealed that a loss in van der Waals interactions leads to the development of resistance to inhibitors due to diminished enzyme-substrate binding. Mutations in the HIV-1 genome outside the protease-coding region also lead to the development of viral resistance to protease inhibitors. These results can be used as bases for developing a new generation of protease inhibitors.

Stable Chinese hamster ovary cell lines expressing wild-type and mutant A2a adenosine receptors (A2aARs) were used to determine the factors involved in desensitization induced after short- and long-term agonist treatments. A small structurally distinct region of the A2aAR carboxy-terminal tail with an associated Thr 298 was found functionally important for rapid but not long-term agonist-mediated desensitization via its phosphorylation by unknown kinases. Such phosphorylation leads to coupling of A2aAR and Gs and adenyl cyclase stimulation, an indication of effector activation.

A study using cloned and purified phage T4 gene 32 (gp32) was conducted to examine the importance of zinc ligands and the factors responsible for maintaining the stability of such metal complexes. gp32 is a zinc metalloprotein that contains a zinc finger motif with one His and three Cys residues. A competitive metal binding assay revealed that the substitution of zinc with cobalt results in the distortion of the tetrahedral coordination symmetry. Changes in amino acid residues also destabilizes the complex to varying degrees, depending on the substitution.

The known inhibitory activity of antisense oligodeoxynucleotides (ODNs) against gene expression via a RNase H pathway was demonstrated in an experiment using C-5-substituted deoxyuridine (dU)-containing ODNs. A microinjection assay was done wherein the C-5 propyne dU ODNs were shown to inhibit the expression of SV40 T-antigen in CV1 cell cultures. The mechanism of action was found consistent with previous findings, that is, the abortion of gene expression occurs due to the RNase H-mediated degradation of RNAs after the selective binding of C-5 propyne dU ODNs to intracellular RNAs.

A novel chromosome mapping technique was developed based on a low coverage shotgun approach and directed sequencing steps. The method was utilized for nucleotide sequencing of the 115 kb chromosomal fragment of the Bacillus subtilis genome. Low coverage shotgun approach for the mapping of the 115 kb chromosomal fragment indicated the presence of 21 open reading frames that belong to seven transcription units. The G+C content of the segment is greater than 47% and contains genes that regulate the synthesis of exopolysaccharide.

Ribozymes are polynucleotide molecules with intrinsic catalytic activity, capable of cleaving nucleic acid substrates. Large RNA molecules were synthesized containing a hammerhead ribozyme moiety of 52 nucleotides linked to an inactive leader sequence, for total lengths of either 262 or 1226 nucleotides. Frozen RNAs were irradiated with high energy electrons. Surviving ribozyme activity was determined using the ability of the irradiated ribozymes to cleave a labeled substrate. The amount of intact RNA remaining was determined from the same irradiated samples by scanning the RNA band following denaturing gel electrophoresis. Radiation target analyses of these data revealed a structural target size of 80 kDa and a ribozyme activity target size of 15 kDa for the smaller ribozyme, and 319 kDa and 16 kDa, respectively, for the larger ribozyme. The disparity in target size for activity versus structure indicates that, in contrast to proteins, there is no spread of radiation damage far from the primary site of ionization in RNA molecules. The smaller target size for activity indicates that only primary ionizations occurring in the specific active region are effective. This is similar to the case for oligosaccharides. We concluded that the presence of the ribose sugar in the polymer chain restricts radiation damage to a small region and prevents major energy transfer throughout the molecule. Radiation target analysis should be a useful technique for evaluating local RNA:RNA and RNA:protein interactions in vitro.

The genes that determine the pathogenicity and virulence of pathogens are identified by various molecular genetic selection and screening methods. The screening methods include forming cDNA from the RNA of pathogens, gene fusion, gene transfer, and comparing the genomes of non-pathogenic and pathogenic microorganisms. Directed and random mutagenesis and transposon mutagenesis are also used. Signature-tagged mutagenesis allows the study of different mutants in one host. An alternative to studying some pathogens in animals is to study them in plants.

Molecular sequence data are beginning to provide important insights into the evolutionary origin of eukaryotic cells. Global phylogenies of numerous protein sequences indicate that the eukaryotic cell nucleus is a chimera, which has received major contributions from both a Gram-negative eubacterium and an archaebacterium. Recent studies also indicate that the formation of the nuclear envelope and the endoplasmic reticulum was accompanied by duplication of genes for the molecular chaperone proteins (e.g. hsp70, hsp90), which facilitate protein transport across membranes. Based on these observations, it is suggested that the ancestral eukaryotic cell arose by a unique endosymbiotic event involving engulfment of an eocyte archaebacterium by a Gram-negative eubacterial host.

Chromosome mapping has become a popular approach for constructing physical maps of bacterial genomes. Pulse-field gel electrophoresis (PFGE), gene encyclopedias and DNA sequencing are the techniques that can be used for mapping genomes of different sizes. Of the three, genome sequencing is the newest, but provides the most sufficient results. However, an evaluation of the results produced by the three techniques revealed a combination of hybridization and limited restriction mapping of encyclopedia elements produces the most complete and specific maps.

A restriction fragment length polymorphism for a human genomic DNA probe (VC85) which is closely linked to the fa locus on rat chromosome 5 was used to genotype the F2 generation of a cross between Zucker and Brown Norway rats. The Zucker fatty (fa/fa) rat is widely used as an animal model for obesity and type II diabetes mellitus, but no effective method has been found so far to identify fa/fa rats before the onset of phenotypic abnormalities. The molecular genetic method provides a solution to this difficulty and thus allows the determination of the earliest metabolic manifestations of the fa/fa genotype long before the onset of phenotypic characteristics.

* Context.--Hereditary benign intraepithelial dyskeratosis (HBID) is a rare autosomal dominant disorder characterized by elevated epibulbar and oral plaques and hyperemic conjunctival blood vessels. The condition is predominantly seen in Native Americans belonging to the Haliwa-Saponi tribe located in northeastern North Carolina. Objective.--To determine whether HBID can be diagnosed using cytologic preparations of the conjunctiva, and whether the cytologic findings correlated with the genetic linkage involving a duplication in chromosome 4 (4q35). Design.--Cytologic preparations from conjunctival brushings in patients afflicted with HBID and from unaffected blood relatives with normal conjunctivas were compared in a masked fashion. Cytologic observations were correlated with molecular genetic analyses. Results.--Papanicolaou-stained preparations from the conjunctiva showed the typical cytologic features of HBID, including rounded squamous epithelial cells with dense homogenous orange cytoplasm and hyperchromatic, pyknotic, or crenated nuclei. All cases with the diagnostic cytologic findings of HBID had a duplication in chromosome 4 (4q35). Conclusion.--HBID is an entity with distinct clinical, histopathologic, and genetic features. The results of this study indicate the diagnosis can also be supported in an appropriate clinical setting when adequate epibulbar cytology preparations are obtained and the characteristic genetic attributes are present. (Arch Pathol Lab Med. 2008;132:1325-1328), Hereditary benign intraepithelial dyskeratosis (HBID) (Mendelial Inheritance of Man [MIM] identification 127600) is a rare autosomal dominant disorder characterized by elevated epithelial plaques located on the ocular and oral mucous [...]

The significance of using molecular genetics methods, which trace animal spatial movement and population, is examined.

Methods of molecular genetics, which examine mating behavior of animals, are presented.

HNPCC (Lynch syndrome) is the most common form of hereditary colorectal cancer (CRC), wherein it accounts for between 2-7 percent of the total CRC burden. When considering the large number of extracolonic cancers integral to the syndrome, namely carcinoma of the endometrium, ovary, stomach, hepatobiliary system, pancreas, small bowel, brain tumors, and upper uroepithelial tract, these estimates of its frequency are likely to be conservative. The diagnosis is based upon its natural history in concert with a comprehensive cancer family history inclusive of all anatomic sites. In order for surveillance and management to be effective and, indeed, lifesaving, among these high-risk patients, the linchpin to cancer control would be the physician, who must be knowledgeable about hereditary cancer syndromes, their molecular and medical genetics, genetic counseling, and, most importantly, the natural history of the disorders, so that the entirety of this knowledge can be melded to highly-targeted management. Keywords: hereditary cancer, cancer genetics, colorectal cancer, Lynch syndrome, Author(s): Henry T. Lynch[sup.1,3] , Jane F. Lynch[sup.1] , Trudy G. Shaw[sup.1] and Jan LubiÅski[sup.2] Introduction The annual worldwide incidence of colorectal cancer (CRC) is approximately 944,717 (males: 498,754; females: [...]

An overview is presented on risk assessment, using as an example recent concerns over the effects of chemical pollution on water-supply quality. Topics include in vitro gene arrays to test impacts at the molecular level.

Methods and reagents is a unique monthly column that highlights current discussions in the newsgroup bionet.molbio.methds-reagnts, available on the Internet. This month's column discusses the pros and cons of various techniques used to shear DNA for shotgun cloning. For details on how to partake in the newsgroup, see the accompanying box., The length of a cloned random genomic DNA fragment for the construction of a genomic library depends on the insert-size limitation of the genetic vector. A technique for the shearing of DNA for genomic library construction and shotgun cloning experiments involved the utilization of the Bio-Nebulizer which efficiently controls the size or length of the DNA fragment. The nebulization of DNA also involved the addition of a genomic DNA fragment in a TE buffer with glycerol and subsequent precipitation of the fragment with ammonium acetate and ethanol.