Category Archives: Volume 23 No. 2 (2001)

Species diversity of moconotyledonous vegetation in Mt.Pangasugan, Leyte, Philippines


Author(s): Pamela M. Po-Abit and Norma Aguilar

Abstract

The species diversity of the monocotyledonous vegetation of Mt. Pangasugan (1,158 m ASL) was described. Four sites (sites 1-91 to 300 m ASL site 2-301 to 600 m ASL site 3-601 to 901 m ASL site 4-900 to 1,158 m ASL) were established to take an inventory of the monocotyledonous flora of the western side of the mountain.
A total of 516 monocotyledonous species representing 51 genera, 76 species belonging to 14 families were recorded. Family Palmae comprised the most number of species whereas Hypoxidaccac and Apostaciaceae had the least number. Scleria scrobiculata (Cyperaceae) was observed to be the most abundant species. Results revealed that the species diversity of the monocotelydonous vegetation of Mt. Pangasugan is affected by altitude. Higher species diversity was observed at lower altitudes than at higher altitudes.

Keywords : Monocotyledons, altitude, Mt. Pangasugan, diversity

Full PDF :
pdf

Altitudinal distribution and quantitative vegetation analysis of the monocotyledonous flora in Mt. Pangasugan, Leyte, Philippines


Author(s): Pamela M. Po-Abit and Norma O. Aguilar

Abstract

The attitudinal distribution of monocotyledonous species in Mt. Pangasugan, Leyte, Philippines was described. Quantitative vegetation analysis to evaluate attitudinal effect was also done from the four sites established in the western side of the mountain.
Hierarchical cluster analysis showed that the families Araceae, Gramineae, Orchidaceae, Palmae, and Zingiberaceae can adapt to wide environmental conditions since these groups were observed in all sites. Cyperaceae preferred the open, welt-lighted and cooler summit. Widely distributed species were Alocasia heterophylia, Alocasia zebrine, and Homalomena philippinensis (Araceae), Schizostachyum diffusum (Gramineae), Languas haenkei, Languas illustris and Globba marantina (Zingiberaceae), Scleria scrobiculata (Cyperaceae), and Heterospathe philippinensis (Palmae). Discriminant analysis revealed that the families Pandanaceae and Apostasineae, Palmae and Araceae, Liliaceae to Orchidaceae and Zingiberaceae were related based on their distribution and frequency in the different sites.

Keywords : Quantitative analysis, discriminant analysis, altitude

Full PDF :
pdf

Biology of yam mealybug, Planococcus pacificus Cox (Hemiptera: Pseudococcidae)


Author(s): Erlinda A. Vasquez and MeIecio A. Buyser

Abstract

The mealybug, Planococcus pacificus Cox, is one of the most important insect pests attacking stored yam in the Philippines. This paper reports the results of our study on the life history of the insect on greater yam (Dioscorea alata var Kinampay). The insect underwent four development stages for the male and three for the female. The total developmental period (egg to adult) lasted 28-30 (28.79) days for the male and 28-30 (33.70) days for the female. The female laid 7-132 eggs/mass for its entire life span. A male to female ratio of 1:4.43 was recorded. Adult male lived shorter (1-4 days) than the female (4-11) days.

Keywords : Yam mealybug, Planococcus pacificus Cox, life history study

Full PDF :
pdf

Effect of some edaphic factors on microbial decomposition of leaf fibre biomass of Toona ciliata Roxb. and Trema orientalis Bl.


Author(s): Sunanda Chanda, Kakali Ghosh, Priyanka Majumbar and Swapan K. Bhaduri1

Abstract

Leaf fiber residue generated as a by-product during the bulk production of leaf protein from forest tree leaves poses disposal problems in the absence of any proper utilisation. The fiber residue can be returned to the forest floor for mineralization as a soil amendment. A short term in vitro study was conducted to determine the microbial population and activity as well as the rate of decomposition of the mixture of leaf fiber residues from two perennial plants viz. Toona ciliata Roxb. and Trema orientalis Bl. in the forest soil in relation to moisture, temperature and pH. The most favourable condition for microbial association and fiber decomposition was found to be 25% moisture content at 35°C and 6.5 pH for microbial association and fiber decomposition. Effects of temperature, moisture and pH on the species composition of fungal flora associated with decomposition were also investigated. Aspergillus, Mucor, Rhizopus, Trichoderma, Penicillium, Cladosporium, etc. were the most common genera isolated from decaying fibrous residues, which ultimately governed the decomposition of leaf fiber in the soil. Some species of Aspergillus such as A. flavus, A. fumigatus, A. nidulans, A. terreus, and some species of Penicillium, Sporotrichum and Thichoderma were found 10 survive at 50°C.

Keywords : Toona caliata, Trema orientalis, leaf fiber biomass, litter. chemical composition, microbial decomposition, edaphic factors, fungal flora

Full PDF :
pdf

Biochemistry of postharvest spoilage of sweetpotato (Ipomoea batatas L.)1. Changes in starch, total sugar, praline and ascorbic acid content


Author(s): R.C. Ray and Swayam Prava Pati

Abstract

Java black rot and soft rot are two important postharvest diseases of sweetpotato caused by Botryodiplodia theobromae Pat. and Rhizopus oryzae Went & Prins. Geerl., respectively. There was a gradual decline in starch and ascorbic acid contents in sweetpotato roots following harvest and this decline was further aggravated by infection by these putative fungi B. theobromae and R. oryzae. However, the total sugar and proline contents did not exhibit much variation between fungi-infected and uninfected tubers.

Keywords : Botryodiplodia theobromae, Ipomoea batatas L. java black rot, Rhizopus oryzae, soft rot, spoilage, sweetpotato

Full PDF :
pdf

Cell-free synthesis of tachyplesin, an antimicrobial peptide from tachypleus tridentatus


Author(s): Edgardo E. Tulin, Anabella B. Tulin, and Shin-ichiro Ejiri

Abstract

Tachyplesin is an antimicrobial peptide isolated from the he es of horseshoe crab (Tachypleus tridentatus). Due to the importance of producing highly active peptides that have great commercial application, we attempted to produce this protein using a continuously coupled transcription-translation in a wheat germ extract system. The system works by using a continuous flow of feeding solution containing nucleoside triphosphates and amino acids into a 1-ml reactor containing wheat germ extract, plasmid DNA, and transcription enzyme, and continuous removal of translation product through an ultrafiltration membrane fitted in the reactor. The amount of protein synthesized reached to about 80 mg after 27 h of continuous reaction. Autoradiogram of the translated product showed a distinct band at about 8.44 kDa corresponding to the calculated molecular weight of tachyplesin. Continuously coupled transcription-translation in a cell-free system offers many possible applications to create new products in biotechnology

Keywords : mil-free protein synthesis, coupled transcription-translation, Tachyplesin, Tachypleus tridentatus, antimicrobial peptide

Full PDF :
pdf

Effective production of recombinant esterase in Bacillus brevis using a pH-controlled fed-batch culture


Author: Edgardo E. Tulin

Abstract

An automated two-component substrate (polypepton plus glucose) feeding strategy with a pH-stat modal fed-batch culture using a high pH limit was developed to effectively produce esterase from a protein-hyperproducing Bacillus brevis HPD31 harboring the plasmid pHSC131 which carries the Bacillus stearothermophilus esterase gene. Highest activity of the secreted esterase (34 U/ml) was obtained when the concentrations of polypepton and glucose in the nutrient feed solution were 250 g/l and 41.60 g/l, respectively. The absence and excessive amount of glucose in the nutrient feed solution were ineffective for extracellular esterase production because without glucose cell growth was minimal while excessive amount of glucose flavored cell growth at the expense of esterase production. The feed rate, automatically controlled by a direct signal of pH change, at 0.30 ml/pulse was found optimum for extracellular esterase secretion. The activity of the secreted esterase was increased more than eight times from 4 U/ml in the conventional batch culture to 34 U/ml obtained in this studs. The esterase productivity was likewise increased more than three-fold.

Keywords : automated substrate feeding, Bacillus brevis, pH-slat modal fed-hatch culture, esterase

Full PDF :
pdf