Volume 3 No. 2

July 2000
Clique Partition Numbers of the Johnson Graphs J (n,2)

Clique Partition Numbers of the Johnson Graphs J (n,2)

pp 40-42 (Vol 3 No. 2 2000)

Rigor B. Ponsones
Mathematics Department
De La Salle University-Manila

ABSTRACT

This paper discusses about clique partitions of a class of Johnson graphs. In particular, it determines the clique partition numbers of the Johnson graphs J(n,2).

Singular and Nonsingular Circulant Asymmetric Digraphs

Singular and Nonsingular Circulant Asymmetric Digraphs

pp 35-39 (Vol 3 No. 2 2000)

Severino V. Gervacio and lsagani B. Jos
Department of Mathematics
De La Salle University
2401 Taft Avenue, 1004 Manila

ABSTRACT

This paper describes two special types of digraphs which arc r-regular, circulant and asymmetric. These graphs are denoted by Crn ‘and dCn. Specifically, this paper shows which of these special classes of r-regular, asymmetric and circulant digraphs are singular and which are non-singular.

Diterpenes from the Soft Coral Clavularia infiata (Coelenterata, Octocorallia, Stolonifera)

Diterpenes from the Soft Coral Clavularia infiata (Coelenterata, Octocorallia, Stolonifera)

pp 25-34 (Vol 3 No. 2 2000)

Glenn V. Alea
Consolacion Y. Ragasa
Chemistry Department, De La Salle University-Manila
2401 Taft Avenue, 1004, Manila, Philippines

ABSTRACT

Three diterpenes were isolated from the dichloromethane extract of the Stolonifer Clavularia inj/ata. The structure of (3S,4S)-clavulara-1 (15), l 7-diene-3,4-diol I was elucidated by ID and 2D NMR spectroscopy while the structures of (4R)-clavulara-1(15),17-diene-4-ol 2 and (JR,4R)­clavulara-17-ene-l,4-diol 3 were determined by comparing their proton NMR spectra with those previously reported.

Genomic Characterization and Physical Mapping of Shigella flexneri Serotype-Specific Antigen V Temperate Bacteriophage

Genomic Characterization and Physical Mapping of Shigella flexneri Serotype-Specific Antigen V Temperate Bacteriophage

pp 18-24 (Vol 3 No. 2 2000)

Dario Angeles 1
Division of Biochemistry and Molecular Biology
School of Life Sciences
Australian National University
Canberra, ACT 0200, Australia

Ma. Theresa M. Montejo 2
Australian Red Cross
159 Clarence, 2000 Sydney NSW,
Australia

ABSTRACT

Shigella jlexnen” hosts a temperate bacteriophage SfV responsible for the conversion ofserotype Y strains (3.4) to serotype 5a (v.· 3. 4) through its glucosyl transferace gene. This enzyme mediated conversion effects a molecu­lar antigenic conversion in glucosyl or glycosylic moiety attachment generating a corresponding immunogenic shift in the O-antigen component of the outer membrane /ipopo/ysacchan”de immune response among Shigellosis patients. With respect 10 vaccine development, further investigation into SJV’s complete genome is crucial to explore and distinctly locate other genetic horizontal tramji?r contributing immunogenicity aside Ji-om the so­matic antigen and proteins encoded by the invasion plasmid. SJV was placed in the group B of the Bradley classi­fication scheme containing an approximate 39 kb intact DNA, double stranded, circularly permutted genome which appeared to be packaged by a headful mechanism at the Pac site. Bacten”ophage SfV showed significant homology at the 2.5 kb fragment C serotype-conversion region of SJX but their morphology and protein profile were different. 1he construction of the physical map of SJV in this study gives a concrete blueprint stipulating the orientation and size of its genome. This inJOrmati.on is vital JOr further studies involving library construction, cloning, sequencing, amino acid expression and fimc­tional evaluation and homology studies. 

Synthesis of sugar functionalized tetrathiafulvalene

Synthesis of sugar functionalized tetrathiafulvalene

pp 11-17 (Vol 3 No. 2 2000)

Gerardo C. Janairo
Chemistry Department, De La Salle University
2410 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

The synthesis and chemistry of the water soluble sugar functionalized tetrathiafulvalenes are discussed. The use of a suitable protecting group for the coupling between oxone and thiones is given along with deprotection and subsequent nucleophilic substitution with halosugars. The potential applications of these promising sugar derivatized tetrathiafulvalenes are hereby enumerated.

A Flavone from Vitex parviflora

A Flavone from Vitex parviflora

pp 6-10 (Vol 3 No. 2 2000)

Consolacion Y. Ragasa 1 , Elaine Morales* and John A. Rideout 2

1 Chemistry Department, De La Salle University
2401 Taft Avenue, 1004 Manila

2 School of Chemical and Biomedical Sciences, Central Queensland
University Rockhampton, Queensland, 4702 Australia

ABSTRACT

The chloroform extract of the air-dried leaves of Vitex parviflora afforded retusin by silica gel chromatography. Its structure was elucidated by extensive 1 D and 2D NMR spectroscopy. Antimicrobial tests indicated that retusin has moderate activity against the fungi, A. niger and low activity against the bacteria, P. aeruginosa. It was found inactive against the fungi, C. albicans and T. mentagrophytes and the bacte­ria: E. coli, S. aureus and B. subtilis. 

Some Related Designs of Paley 2-designs of QN-type

Some Related Designs of Paley 2-designs of QN-type

pp 1-5 (Vol 3 No. 2 2000)

Blessilda P. Raposa
Mathematics Department, De La Salle University
2401 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

Paley 2-designs of QN-type are symmetric 2- designs where q is a prime power such that q= 1 (mod 4). The main results of this paper show  that the Paley 2-designs ofQN-type and their comple­ments are self-dual.