Rhythmic flashing behavior of synchronous flashing fireflies from Malaysia and New Guinea was studied. The "circa second" firefly pacemaker has characteristics analogous to circadian rhythms, such as entrainment, phase shifting, limits of entrainment, fringe entrainment, and effects of the light:dark ratio on phase. The three species studied show different phase-response curves; a light pulse causes a large phase shift in one firefly species (Pteroptyx cribellata) but small phase shifts in others (Pteroptyx malaccae and Luciola pupilla). Comparative studies of the phase angle differences between the animal's flash and the flash of a controlled light source suggest at least two different mechanisms of attaining synchrony: 1) by cycle-to-cycle phase shifting of a stable oscillator; 2) by changing the underlying period (tau) of a variable oscillator.
Recent developments in breastfeeding are reviewed in relation to species-specific adaptive suckling and the level of maturity of the newborn. Scientific advantages and advances are noted concerning biochemistry, protective substances, emotional differences, child spacing and economics. The significance of unimpaired maternal reflexes and the need for information is stressed with regard to successful lactation and as common causes of inadequacy. The components needed in varying degrees, in breastfeeding programmes are mentioned briefly.
Aedes albopictus (Skuse) is an Asian mosquito that recently has colonized North America via used tire transport. Temperate Ae. albopictus populations overwinter as diapausing eggs, but tropical populations cannot diapause. Eggs of tropical (SABAH) and temperate (INDY) Ae. albopictus were obtained in diapause-inducing conditions and placed inside a scrap tire to monitor overwintering survival in northern Indiana during the winters of 1989-1990 and 1990-1991. Diapause eggs of Ae. triseriatus (Say), a native North American mosquito, were included for comparison. Tropical Ae. albopictus from Malaysia did not survive either winter. Temperate Ae. albopictus from Indianapolis, IN, did not survive the winter of 1989-1990, but 78% survived the winter of 1990-1991. In contrast, 92 and 96% of Ae. triseriatus survived the winters of 1989-1990 and 1990-1991, respectively. Neither mean temperature nor absolute minimum temperature (a winter's lowest temperature) accurately predicted Ae. albopictus overwintering survivorship in the field. The possible effect of snow and other insulating materials on the overwintering survivorship of Ae. albopictus eggs is discussed.
Studies on toxicities and tolerances of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in the brown alga Isochrysis galbana and in the green-lipped mussel Perna viridis were conducted by short-term bioassays using endpoints growth production and mortality, respectively. The 5-day EC(50) and 24-h LC(50) of these heavy metals were determined in the brown alga and mussel, respectively. The EC(50) values calculated for the alga were 0.74 mg/l for Cd, 0.91 mg/l for Cu, 1.40 mg/l for Pb and 0.60 mg/l for Zn. The LC(50) values for the mussels were 1.53 mg/l for Cd, 0.25 mg/l for Cu, 4.12 mg/l for Pb and 3.20 mg/l for Zn. These LC(50) values were within the concentration ranges as reported by other authors who used P. viridis as the test organism. Based on these EC(50) and LC(50) values, the alga was most sensitive to Zn, followed by Cd, Cu and Pb while the mussel was most sensitive to Cu, followed by Cd, Zn and Pb. Differences in the trophic levels, metal handling strategies, biology and ecology of the primary producer (brown alga) and the primary consumer (mussel) are believed to be the plausible causes for the different toxicities and tolerances of the metals studied.
The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.
In our centre the non-availability computerized exercise machines limits the objective monitoring of strength rehabilitation. We undertook this research programme to objectively measure triceps muscle strength by interfacing NORSK-Gym machine with accelerometer and positional transducers to a computer. This data was tabulated and processed using Microsoft Excel. The positional transducer was first calibrated and it showed an excellent Pearson Correlation Coefficients against a standard metric reading (r = 0.9999). Peak Force was used as a test parameter for isotonic triceps muscle strength measurements. The criterion-referenced validity was established as the peak forces measured using the accelerometer and positional transducer demonstrated identical Peak Forces (r = 0.94). Analysis of our mean Peak Force measurements using non-biological force as well as the intra-individual reproducibility demonstrated excellent Pearson Correlation Coefficients (r) = 0.982-0.998 and 0.929-0.972 respectively. This computerized adaptation of the NORSK-Gym machine produced an objective, valid and reproducible triceps muscle strength measurement.
The effect of low-intensity exercise in the heat on thermoregulation and certain biochemical changes in temperate and tropical subjects under poorly and well-hydrated states was examined. Two VO2max matched groups of subjects consisting of 8 Japanese (JS) and 8 Malaysians (MS) participated in this study under two conditions: poorly-hydrated (no water was given) and well-hydrated (3 mL x Kg(-1) body weight of water was provided at onset of exercise, and the 15th, 35th and 55th min of exercise). The experimental room in both countries was adjusted to a constant level (Ta: 31.6+/-0.03 degrees C, rh: 72.3+/-0.13%). Subjects spent an initial 10 min rest, 60 min of cycling at 40% VO2max and then 40 min recovery in the experimental room. Rectal temperatures (Tre) skin temperatures (Tsk), heart rate (HR), heat-activated sweat glands density (HASG), local sweat rate (M sw-back) and percent dehydration were recorded during the test. Blood samples were analysed for plasma glucose and lactate levels.The extent of dehydration was significantly higher in the combined groups of JS (1.43+/-0.08%) compared to MS (1.15+/-0.05%). During exercise M sw-back was significantly higher in JS compared to MS in the well-hydrated condition. The HASG was significantly more in JS compared to MS at rest and recovery. Tre was higher in MS during the test. Tsk was significantly higher starting at the 5th min of exercise until the end of the recovery period in MS compared to JS. In conclusion, tropical natives have lower M sw-back associated with higher Tsk and Tre during the rest, exercise and recovery periods. However, temperate natives have higher M sw-back and lower Tsk and Tre during experiments in a hot environment. This phenomenon occurs in both poorly-hydrated and well-hydrated states with low intensity exercise. The differences in M sw-back, Tsk and Tre are probably due to a setting of the core temperature at a higher level and enhancement of dry heat loss, which occurred during passive heat exposure.
Genetic divergence in geographically isolated populations is a prerequisite for allopatric speciation, one of the most common modes of speciation. In ecologically equivalent populations existing within a small, environmentally homogeneous area, an important role for environmentally neutral divergence is often found or inferred. We studied a species complex of conspicuously shaped Opisthostoma land snails on scattered limestone outcrops within a small area of lowland rainforest in Borneo. We used shell morphometrics, mitochondrial and nuclear DNA sequences, and marks of predation to study the factors involved in allopatric divergence. We found that a striking geographic divergence exists in shell morphology, which is partly associated with neutral genetic divergence. We also found geographic differentiation in the behavior of the snails' invertebrate predator and evidence of an evolutionary interaction between aspects of shell shape and predator behavior. Our study shows that adaptation to biotic aspects of the environment may play a more important role in allopatric speciation than previously suspected, even on a geographically very small scale.
Gryphopsylla maxomydis n. sp. (Pygiopsyllidae), Medwayella rubrisciurae n. sp. (Pygiopsyllidae) and Macrostylophora theresae n. sp. (Ceratophyllidae) are described from endemic rodents in Sulawesi. Gryphopsylla maxomydis was collected from the murids Maxomys musschenbroekii and Paruromys dominator in Central Sulawesi (Sulawesi Tengah). However, M. musschenbroekii appears to be the true host of this flea because it has spiny pelage and G. maxomydis shows morphological adaptations for parasitizing spiny hosts including a remarkable "beak-like" structure on the head. This adatation is similar to a beak-like structure on the head of Gryphopsyllo hopkinsi (Traub) which parasitizes the spiny murid Maxomys whiteheadi in Borneo (Sabah). Medwayella rubrisciurae was collected from the large tree squirrel Rubrisciurus rubriventer in Central Sulawesi and this represents the first report of this flea genus in Sulawesi. Macrostylophora theresce was recorded from the murids Bunomys fratrorum, P. dominator and Rattus xanthurus in North Sulawesi (Sulawesi Utara); most other members of this flea genus parasitize squirrels in the Oriental and Palaearctic zoogeographical regions.
Much of the literature on the relationship between species richness or functional group richness and measures of ecosystem function focuses on a restricted set of ecosystem function measures and taxonomic groups. Few such studies have been carried out under realistic levels of diversity in the field, particularly in high diversity ecosystems such as tropical forests. We used exclusion experiments to study the effects of dung beetle functional group richness and composition on two interlinked and functionally important ecological processes, dung removal and secondary seed dispersal, in evergreen tropical forest in Sabah, Malaysian Borneo. Overall, both dung and seed removal increased with dung beetle functional group richness. However, levels of ecosystem functioning were idiosyncratic depending on the identity of the functional groups present, indicating an important role for functional group composition. There was no evidence for interference or competition among functional groups. We found strong evidence for overyielding and transgressive overyielding, suggesting complementarity or facilitation among functional groups. Not all mixtures showed transgressive overyielding, so that complementarity was restricted to particular functional group combinations. Beetles in a single functional group (large nocturnal tunnellers) had a disproportionate influence on measures of ecosystem function: in their absence dung removal is reduced by approximately 75%. However, a full complement of functional groups is required to maximize ecosystem functioning. This study highlights the importance of both functional group identity and species composition in determining the ecosystem consequences of extinctions or altered patterns in the relative abundance of species.
The amended diagnosis of the genus Pratylenchoides and list of its valid species with synonyms are given. All the efficient diagnostic characters are listed. Modern taxonomic standard for the description of Pratylenchoides species is proposed; it may be used also in taxonomic databases. Tabular and text keys for all species of the genus are given. Five following groups are considered within the genus Pratylenchoides. The group arenicola differs from other groups in the primitive adanal bursa type; the groups magnicauda, crenicauda, ritteri, and megalobatus differ from each other in the position of cardium along the body axis in relation to the pharyngeal gland nuclei, pharynx types are named according to the stages of its evolution from the primitive tylenchoid pharynx (cardium situated posteriorly) to the advanced hoplolaimoid one (cardium situated anteriorly). Diagnoses and species compositions of the groups are given. Basing on the matrix of species characters, the dendrogram has been generated for all species of Pratylenchoides and for all characters (UPGMA, distance, mean character difference, random, characters ordered). Taking in view that the PAUP software gives equal weights to all characters, including the most important ones which define the prognostic species groups, the separate dendrograms for each prognostic species group were generated using the same above mentioned tree parameters. On the base of the records of Pratylenchoides species the matrices of plant host ranges, geographic distribution, and preferred soil-climatic conditions were developed. The dendrograms of the faunal similarities were generated using these matrices, with conclusions on a possible origin and evolution of the genus. The genus evolved from the flood lands with swampy soils and prevalence of dicotyledons (herbaceous Lamiaceae and woody Salicaceae families) to the forest mainland communities with balanced humidity and predominance of herbaceous Poaceae and Fabaceae with woody Fagaceae, Betulaceae, and Oleaceae. The leading factor of the evolutional adaptation to soil-climatic conditions was the factor of humidity, but its significance gradually decreased with the host change to more advanced plant taxa adapted to the communities with more dry balanced humidity. The genus took its origin on the south shores of Laurasia in the Cainozoe. Later, when Hindistant and Arabian Peninsula joined with Laurasia creating the Himalayas barrier, the Pratylenchoides spp. distributed by two branches: the northern one moved into Central Asia, East Europe and North America, and the south branch came into Indo-Malaya, West Asia and the north of Africa. The remnants of the ancient species groups remain in West Europe and East Asia. In the North America the genus gave an origin to its sister genus Apratylenchoides, which spread to the south up to Antarctica; another advanced branch spread in the North America reaching Alaska.
A study was conducted on the long term effects of nine heavy metals on the Chironomus plumosus and Culicoides furens larvae. This study tested the effect of the heavy metals on several generations of the larvae to observe the formation of increased hardiness against pollutants present within the aquatic habitat. From this study it was observed that susceptibility or sensitivity to heavy metals decreased with LC50 values becoming larger indicating a decreased toxicity level. Significant variations (p < 0.05) were observed between first generation and third generation culicoides for all metals and at all concentrations. Variations between third and fourth generation culicoides were also significantly different (p < 0.05) with the exception of chromium at 25 degrees C and nickel and lead at every temperature range group. The variation between all generations 4, 5 and 6 was found to be insignificant (p > 0.05). This would indicate that metal tolerance would have occurred in these generations and the effect of metals was less toxic to the culicoides. Generation 9 was found to have LC50 values (p > 0.05) the same as the LC50 values obtained in third generation culicoides. Thus it would appear that heavy metal resistance was developed when the organisms were exposed to prolonged exposure of the heavy metals but was lost when the organisms were bred in non-contaminated water.
Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO(2) and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO(2), (II) bicarbonate plus continuous sparging of CO(2), and (III) only bicarbonate. The pH-reducing nature of CO(2) showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO(3)(-)-N/g MLVSS/h for degrading 20 and 30 mg NO(3)(-)-N/L and 9.09 mg NO(3)(-)-N/g MLVSS/h for degrading 50mg NO(3)(-)-N/L.
During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land.
Athletes in Malaysia need to perform in a hot and humid environment due to the climatic nature of the country. Chronic supplementation of Panax ginseng (PG) (a deciduous perennial plant belonging to the Araliaceae family) enhances physical performance. As the ergogenic effect of acute supplementation of PG on endurance performance has not been explored in the Malaysian population especially in a hot and humid condition this study was taken up.
Fresh water, coupled with soil salinization in many areas has resulted in an increased need forscreening of salt tolerant turf grasses. Relative salinity tolerance of eightwarm season turfgrass species were examined in this study in sand culture. Grasses were grown in a glasshouse, irrigated with either distilled water or saline sea water adjusted to 24, 48 or 72 dSm-1. Salt tolerances of the grasses were assessed on the basis of their shoot and root growth, leaf firing and turf quality. Regression analysis indicated that Zoysiajaponica (Japanese lawn grass) (JG), Stenotaphrum secundatum (St. Augustine) (SA), Cynodon dactylon (satiri) (BS), Zoysia teneuifolia (Korean grass) (KG), Digitaria didactyla (Serangoon grass) (SG), Cynodon dactylon (Tifdwarf) (TD), Paspalum notatum (Bahia grass) (BG) and Axonopus compressus(Pearl blue) (PB) suffered a 50% shoot growth reduction at 36.0, 31.8, 30.9, 28.4, 26.4, 25.7, 20.0 and 18.6 dSm1 of salinity, respectively and a root growth reduction at44.9, 43.7, 33.4, 31.0, 29.5 27.5, 21.5 and 21.4 dSm- of salinity, respectively. Leaf firing and turf quality of the selected species, as a whole, were also found to be affected harmoniously with the change in root and shoot growth. On the basis of the experimental results the selected species were ranked for salinity tolerance as JG>SA>BS>KG>SG >TD>BG>PB.
The mature ARM lipase gene was cloned into the pTrcHis expression vector and over-expressed in Escherichia coli TOP10 host. The optimum lipase expression was obtained after 18 h post induction incubation with 1.0mM IPTG, where the lipase activity was approximately 1623-fold higher than wild type. A rapid, high efficient, one-step purification of the His-tagged recombinant lipase was achieved using immobilized metal affinity chromatography with 63.2% recovery and purification factor of 14.6. The purified lipase was characterized as a high active (7092 U mg(-1)), serine-hydrolase, thermostable, organic solvent tolerant, 1,3-specific lipase with a molecular weight of about 44 kDa. The enzyme was a monomer with disulfide bond(s) in its structure, but was not a metalloenzyme. ARM lipase was active in a broad range of temperature and pH with optimum lipolytic activity at pH 8.0 and 65°C. The enzyme retained 50% residual activity at pH 6.0-7.0, 50°C for more than 150 min.
An investigation was made to see the salt tolerance of 10 weed species of rice. Properly dried and treated seeds of weed species were placed on 9 cm diameter petridishes lined with Whatman No. 1 filter paper under 6 salinity regimes, viz. 0 (control), 4, 8, 16, 24 and 32 dS m(-1). The petri dishes were then kept in germinator at 25 +/- 1.0 degrees C and 12 hr light. The number of germinated seeds were recorded daily. The final germination percentage, germination index (GI), seedling vigour index, mean germination time and time for 50% germination were estimated. Root and shoot lengths of the weed seedlings were measured at 20 days after salt application and relative growth values were calculated. Results revealed that salinity decreased final germination percentage, seed of germination as measured by GI, and shoot and root length in all the species. Germination of most of the weed seeds was completely arrested (0) at 32 dS m(-1) salinity except in E. colona (12%) and C. iria (13.9%). The species C. iria, E. colona, J. linifolia and E. crusgalli showed better germination (above 30%) upto 24 dS m(-1) salinity level and were regarded as salt-tolerant weed species. J. linifolia, F. miliacea, L. chinensis and O. sativa L. (weedy rice) were graded as moderately tolerant and S. zeylanica, S. grosus and C. difformis were regarded as least tolerant weed species.