A new deletion in 5′-end of dystrophin gene removing M and P promoters and dystrophin muscle enhancers

We describe a 3-year-old boy who, at age of 8 months, during investigations for upper respiratory tract infection was found to have an incidental grossly elevated CK of 20,000 UI/l. Investigations showed only mild calf hypertrophy and absent Gower's sign, normal cognitive function. Electromyography (EMG) showed myopathic features. Electrocardiography and echocardiography were normal. His muscle biopsy revealed myopathic features indicating Duchenne-type dystrophy. Immunohistochemistry for dystrophin N-terminal, C-terminal and mid-rod antibodies analysis showed the complete absence of dystrophin in the muscle fibers. Genetic studies showed a 141.1 Kb deletion removing muscle promoter, muscle exon 1, Purkinje promoter, Purkinje exon 1, dystrophin muscle enhancers similar to one previously reported in a DMD patient who exhibited some residual expression of dystrophin. The difference in dystrophin expression between these two patients might be due to the extension of deletions. The precise delimitation of the macrodeletion here described provides a better understanding of functional organization of the 5′ end of the DMD gene.     

Sequential organization of grooming behaviors of the mosquito,Aedes triseriatus

Grooming behavior was studied in adult females of the mosquito Aedes triseriatus(Say). The grooming repertoire consisted of 12 different behaviors (accounting for bilateral symmetry) organized into five sequences. The proboscis and antennae were scraped by the forelegs, whereas the dorsal and ventral surfaces of the wings, and the forelegs, midlegs, hindlegs, and tip of the abdomen were scraped by the hindlegs. Each sequence ended with hindleg groomng. Tibial grooming combs were found on the ventral apices of the fore- and hind-tibiae but not on the mid-tibiae. A multidimensional scaling procedure grouped the grooming behaviors in two ways: (1) by the relative position of the groomed structure along the anteroposterior axis of the insect's body, and (2) by whether the groomed structure has a locomotory or sensory function. This suggests that mosquitoes groom both to clear sensilla of obstructive matter and to clean and smooth scales on legs and wings, possibly to decrease drag during flight.     

Structure,biosynthesis, and function of salivary mucins

The glandular secretions of the oral cavity lining the underlying buccal mucosa are highly specialized fluids which provide lubrication, prevent mechanical damage, protect efficiently against viral and bacterial infections, and promote the clearance of external pollutants. This mucus blanket contains large glycoproteins termed mucins which contribute greatly to the viscoelastic nature of saliva and affect its complex physiological activity. The protein core of mucins consists of repetitive sequences, rich inO-glycosylated serine and threonine, and containing many helix-breaking proline residues. These features account for the extended, somewhat rigid structure of the molecule, a high hydrodynamic volume, its high buoyant density, and high viscosity. The oligosaccharide moiety of salivary mucins accounts for up to 85% of their weight. The oligosaccharide side chains exhibit an astonishing structural diversity. The isolation, composition, structure, molecular characteristics, and functional relevance of salivary mucins and their constituents is discussed in relation to recent advancements in biochemistry and molecular biology.Abbreviations: Abbreviations follow the Rules of Carbohydrate Nomenclature of the American Chemical Society, Carbohydrate Division. All sugars are of thed configuration, exceptl-fucose     

Oligonucleotide fingerprinting and RAPD analysis of Achillea species: Characterization and long-term monitoring of micropropagated clones

Two different DNA fingerprinting techniques were applied to a set of Achillea samples (Asteraceae), comprising ten taxa of the medicinally important A. millefolium group and six related species. Field-grown as well as in vitro-micropropagated plants were individually screened for abundance and polymorphism of target sequences recognized by oligonucleotide fingerprinting with 13 different microsatellite-complementary probes. While most probes revealed a high level of intra- and interspecific variability, fingerprints proved to be somatically stable in vegetatively propagated plant material. Analysis of the same samples by polymerase chain reaction with arbitrary 10-mer primers yielded less polymorphic patterns. Because of its higher discriminatory ability, oligonucleotide fingerprinting offers itself as the method of choice for the identification and discrimination of A. asplenifolia and A. roseoalba clones, as well as for monitoring their stability during micropropagation.Abbreviations BPA N-benzyl-9-[2-tetrahydropyranyl]-adenine - PCR polymerase chain reaction - RAPD random amplified polymorphic DNA - RFLP restriction fragment length polymorphism - TAE buffer 40 mM Tris acetate, 20 mM sodium acetate, 1 mM EDTA, pH 7.8 Part of the Ph.D. Thesis     

The Application of Hunter's Inequality in Simultaneous Testing

Using the inequality given by HUNTER (1976) critical limits are derived on the basis of bivariate distributions of the respective statistics for various situations of simultaneous hypothesis testing. The gain in power as compared to the widely used Bonferroni-inequality can be considerable if at least some of the simultaneously investigated test-statistics are highly correlated. In such situations, the loss in power as compared to the use of the exact critical limits might be negligible for practical purposes, the exact limits often being hardly accessible.     

The problem of the eukaryotic genome size

The current state of knowledge concerning the unsolved problem of the huge interspecific eukaryotic genome size variations not correlating with the species phenotypic complexity (C-value enigma also known as C-value paradox) is reviewed. Characteristic features of eukaryotic genome structure and molecular mechanisms that are the basis of genome size changes are examined in connection with the C-value enigma. It is emphasized that endogenous mutagens, including reactive oxygen species, create a constant nuclear environment where any genome evolves. An original quantitative model and general conception are proposed to explain the C-value enigma. In accordance with the theory, the noncoding sequences of the eukaryotic genome provide genes with global and differential protection against chemical mutagens and (in addition to the anti-mutagenesis and DNA repair systems) form a new, third system that protects eukaryotic genetic information. The joint action of these systems controls the spontaneous mutation rate in coding sequences of the eukaryotic genome. It is hypothesized that the genome size is inversely proportional to functional efficiency of the anti-mutagenesis and/or DNA repair systems in a particular biological species. In this connection, a model of eukaryotic genome evolution is proposed.     

Plasmodium falciparum: genetic polymorphism in apical membrane antigen-1 gene from Indian isolates

A number of stage-specific antigens have been characterized for vaccine development against Plasmodium falciparum malaria. This study presents a comprehensive analysis of the sequence polymorphism in Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) in population samples from the eastern and western parts of India. This is the first study of its kind for the nearly full length PfAMA-1 gene from these regions in India. Our observations confirmed that sequence diversity of PfAMA-1 confines only to point mutations and shows 4-8% variation as compared to the prototypes. As opposed to the previous studies on PfAMA-1, our study revealed a greater degree of polymorphism in the Domain II region of PfAMA-1 protein, though signature for diversifying selection is seen throughout the gene. Our present investigation also indicates a very high degree of variation in the reported T- and B-cell epitopes of PfAMA-1. Few noteworthy and unique observations made in this study are the substitution of Cysteine residues responsible for the disulfide bond structure of the protein and the presence of premature termination after 595 amino acids in 3 of the 13 isolates under consideration. These crucial findings add new perspectives to the future of AMA-1 research and could have major implications in establishing AMA-1 as a vaccine candidate.     

Trypanosoma brucei: differential requirement of membrane potential for import of proteins into mitochondria in two developmental stages

Trypanosome alternative oxidase (TAO) and the cytochrome oxidase (COX) are two developmentally regulated terminal oxidases of the mitochondrial electron transport chain in Trypanosoma brucei. Here, we have compared the import of TAO and cytochrome oxidase subunit IV (COIV), two stage-specific nuclear encoded mitochondrial proteins, into the bloodstream and procyclic form mitochondria of T. brucei to understand the import processes in two different developmental stages. Under in vitro conditions TAO and COIV were imported and processed into isolated mitochondria from both the bloodstream and procyclic forms. With mitochondria isolated from the procyclic form, the import of TAO and COIV was dependent on the mitochondrial inner membrane potential (delta psi) and required protein(s) on the outer membrane. Import of these proteins also depended on the presence of both internal and external ATP. However, import of TAO and COIV into isolated mitochondria from the bloodstream form was not inhibited after the mitochondrial delta psi was dissipated by valinomycin, CCCP, or valinomycin and oligomycin in combination. In contrast, import of these proteins into bloodstream mitochondria was abolished after the hydrolysis of ATP by apyrase or removal of the ATP and ATP-generating system, suggesting that import is dependent on the presence of external ATP. Together, these data suggest that nuclear encoded proteins such as TAO and COIV are imported in the mitochondria of the bloodstream and the procyclic forms via different mechanism. Differential import conditions of nuclear encoded mitochondrial proteins of T. brucei possibly help it to adapt to different life forms.     

DNA分子标记技术在生态学研究中的应用

分子生物学几种常见的分子标记技术如RFLP,RAPD,微卫星法,DNA序列分析使生态学研究从宏观步入了微观领域,极大的推动了生态学的发展,对这几种分子标记技术在生态学中的应用及其进展进行了综述,并比较了这些分子生物学技术各自的优缺点.