Showing papers by "University of the Philippines published in 2006"

Estimation under purposive sampling

Abstract: Purposive sampling is described as a random selection of sampling units within the segment of the population with the most information on the characteristic of interest. Nonparametric bootstrap is proposed in estimating location parameters and the corresponding variances. An estimate of bias and a measure of variance of the point estimate are computed using the Monte Carlo method. The bootstrap estimator of the population mean is efficient and consistent in the homogeneous, heterogeneous, and two-segment populations simulated. The design-unbiased approximation of the standard error estimate differs substantially from the bootstrap estimate in severely heterogeneous and positively skewed populations.

Comparing tropical forest tree size distributions with the predictions of metabolic ecology and equilibrium models

Abstract: Tropical forests vary substantially in the densities of trees of different sizes and thus in above-ground biomass and carbon stores. However, these tree size distributions show fundamental similarities suggestive of underlying general principles. The theory of metabolic ecology predicts that tree abundances will scale as the -2 power of diameter. Demographic equilibrium theory explains tree abundances in terms of the scaling of growth and mortality. We use demographic equilibrium theory to derive analytic predictions for tree size distributions corresponding to different growth and mortality functions. We test both sets of predictions using data from 14 large-scale tropical forest plots encompassing censuses of 473 ha and > 2 million trees. The data are uniformly inconsistent with the predictions of metabolic ecology. In most forests, size distributions are much closer to the predictions of demographic equilibrium, and thus, intersite variation in size distributions is explained partly by intersite variation in growth and mortality.

Prototypical solitons in the South China Sea

Abstract: [1] Surface signatures associated with non-linear internal waves are often seen in satellite images of the western South China Sea (SCS) slope and shelf. Observation in the deep sea, to the east, are rare. Here we report on the evolution of an energetic packet as it propagated through the deep central basin of the SCS, toward the western slope and shelf. The waves have amplitudes estimated at 170 m, half widths of 3 km, and phase speeds of 2.9 ± 0.1 m/s, faster than the mode-1 linear phase speed of 2.6 m/s. The shape and observed phase speed were consistent with the Korteweg-deVries (KdV) model over the 65-km path that they were tracked. The intrinsic velocity shear of the waves is small compared to pre-existing shears, and the waves exhibit weak turbulence. The KdV fit and a satellite-derived estimate of horizontal wave extent imply a westward energy flux of 4.5 GW for each crest.

Beyond access to ICTs: Measuring capabilities in the information society

Abstract: This article discusses the development paradigms linked to the idea of an information society and explains how information and communication technologies (ICTs) are seen as a means to development. The article also looks at the concept of a ‘digital divide’ and the universal access to ICT policies that are meant to address the problem. It elaborates on the limitations of how current policies address issues related to how people gain access to and use ICTs. Finally, the article proposes a model for applying Sen’s capability approach to analyze access to ICTs impact on development.

Nitrogen Utilization Efficiency: Relationships with Grain Yield, Grain Protein, and Yield-Related Traits in Rice

Abstract: Rice (Oryza sativa L.) breeders have historically not included nitrogen utilization efficiency (NUE) as a selection criterion in breeding for cultivars, even though it has economic and ecological implications. This study examined the significance and magnitude of variation in N content, NUE, N translocation ratio (NTR), and grain protein concentration among diverse rice genotypes. Fifteen rice genotypes were studied representing the combinations of low and high levels of four yield-related traits: maximum number of tillers, grain mass, main culm panicle node number, and panicle mass. These genotypes included ‘Lemont’, ‘Teqing’, and 13 advance recombinant inbred genotypes obtained from a Lemont 3 Teqing cross. Field data were obtained from experiments conducted during two cropping seasons. Plant samples were analyzed for N concentration. There was significant variation in N content and NUE among genotypes. The genotype NUE means ranged from 25.3 to 63.9 kg grain kg 21 N in a square meter of plants (kg grain kg 21 N), with the top four NUE values ranging from 56.6 to 63.9 kg grain kg 21 N. Nitrogen content and NUE were not significantly correlated with each other, and they had significant positive direct effects on grain yield. Grain yield was positively correlated with NUE, N content, and NTR, whereas NTR was correlated with grain protein concentration. Plant breeders could use these significant correlations to their advantage in breeding for rice cultivars that not only produce high yield but also utilize N efficiently and produce grain with a higher protein concentration.

Trade liberalization and the diet transition: a public health response

Abstract: SUMMARY Trade liberalization remains at the forefront of debates around globalization, particularly around the impact on agriculture and food. These debates, which often focus on how poorer countries can ‘trade their way’ out of poverty, pay limited attention to dietary health, especially in the light of the WHO’s Global Strategy for Diet, Physical Activity and Health (2004), which warned that future health burdens will be increasingly determined by diet-related chronic diseases. This article examines the diet transition as the absent factor within debates on liberalizing trade and commerce. We describe the evolution of trade agreements, noting those relevant to food. We review the association between trade liberalization and changes in the global dietary and disease profile. We illustrate some of the complex linkages between trade liberalization and the ‘diet transition’, illustrated by factors such as foreign direct investment, supermarketization and cultural change. Finally, we offer three scenarios for change, suggesting the need for more effective ‘food governance’ and engagement by public health advocates in policy making in the food and agriculture arena.

A new MADS-box gene (IbMADS10) from sweet potato (Ipomoea batatas (L.) Lam) is involved in the accumulation of anthocyanin

Abstract: A new MADS-box gene designated as IbMADS10 was cloned and its expression was characterized from sweet potato (Ipomoea batatas (L.) Lam.) cv. Beniazuma. The deduced amino acid sequence of the gene indicated high homology with members of the MADS-box family of transcription factors. IbMADS10 shares high amino acid sequence similarity with the DEFH28 of Antirrhinum majus (64%) and with BpMADS4 of Betula pendula (61%) of the SQUA subfamily. Southern blot analysis revealed that the IbMADS10 is present in one or low copy number in the sweet potato genome. The gene is specifically expressed in the pigmented tissues such as in the flower bud, in the pink and in red roots, and hence, it was speculated that the IbMADS10 gene might be correlated with anthocyanin biosynthesis in sweet potato. RNA blot expression of the anthocyanin biosynthesis genes encoding for CHS, CHI, F3H, DFR, ANS and UFTG carried out in the tissues where the IbMADS10 gene was expressed revealed similar transcript levels in all tissues where the IbMADS10 gene is highly expressed, indicating that the IbMADS10 gene is highly correlated with the anthocyanin biosynthesis genes. Another important aspect is the pigmented phenotypes of transgenic calli that ectopically express the IbMADS10 gene, thereby supporting its involvement in the developmental regulation of pigment formation. Tissue printing result further strengthens the hypothesis that the IbMADS10 gene is indeed involved in anthocyanin pigmentation in sweet potato. As the purpose of the IbMADS10 gene is pigmentation, its function, therefore, resembles that of the transparent testa (tt) genes of Arabidopsis.

New Philippine record of south american sailfin catfishes (Pisces: Loricariidae)

Abstract: A taxonomic and biogeographic study of the introduced suckermouth armored catfishes locally known as “janitor fish” is briefly described. Specimens were collected from five sites in the Laguna de Bay basin and were examined for 19 meristic and 37 morphometric characters and other external features including coloration. Results were compared with existing literature on fishes in the family Loricariidae. Examination revealed that specimens of janitor fish, previously reported as Hypostomus plecostomus, actually belong to the genus Pterygoplichthys, family Loricariidae. Collected specimens consisted of two species—Pterygoplichthys disjunctivus and Pterygoplichthys pardalis. Both species were collected from the five sites except in Pasig River where only P. disjunctivus was collected.

Analysing Socio-Demographic Differences in the Access & Use of ICTs in the Philippines Using the Capability Approach

Abstract: This paper presents disaggregated survey data on ICT ownership, access to public ICT facilities, capabilities and actual use of ICTs in two locations in the Philippines: Carmona and Puerto Princesa City. The results showed that the diversity in a location’s topography and differences among people complicates the problem of access. In areas that are more isolated, distance and lack of infrastructure remain the biggest hurdles. In more developed areas, however, social issues like lack of motivation, skills and knowledge may hamper people’s perception of how an ICT can benefit their lives. The results also supported the general expectation that people who are younger, more affluent, well-educated and live in areas with better infrastructure tend to have better access and are more capable in using ICTs. But, overall, income and remoteness were the critical barriers that need to be overcome if ICTs are to be meaningful for more people. This is because income influences not only the affordability of ICT services, but also the level of education (and therefore the skills) that also factors into increased relevance for ICT use. Remoteness, on the other hand, is relevant with respect to the physical availability and access of needed ICT infrastructure. It was also revealed that use of ICTs such as the land line phone and cell phone are still predominantly social, rather than work-related. The results also showed how technological innovation and social intermediation have been helpful in overcoming some of these barriers. For one, wireless options, such as cell phones, have been instrumental in bringing access to areas that landline services could not reach, and likewise, with new payment options (i.e. prepaid), and technologies (i.e. short messaging systems (SMS)), more people are able to find the use of ICTs more affordable and payment less restricting. This paper uses the capability approach (Sen, 1999) to evaluate the implementation outcome of universal access to ICT policies and strategies. It investigates the real opportunities available for households to access ICTs; the characteristics of people who use and not use these facilities; and their reasons for using them. To do so, the study discusses the results of surveys conducted in Carmona and Puerto Princesa City. Carmona is a semi-industrial municipality in close proximity to Metro Manila. Puerto Princesa, on the other hand, is the capital city of Palawan, an island province detached from Luzon Island. This study describes the state of access to ICTs in these two locations. It then presents the results of field surveys that were conducted there: discussing what access to ICT means to people, and how access or lack thereof affects them.

Vitamin D replacement for cirrhosis-related bone disease

Abstract: The osteoporotic fracture rate in patients with chronic liver disease is approximately twice that of age-matched, control individuals. About 66% of patients with moderately severe cirrhosis and 96% of patients awaiting liver transplantation have vitamin D deficiency. Studies have shown a strong correlation between vitamin D deficiency and bone density, particularly in the hip. Previous studies of vitamin D therapy in cirrhosis-related bone disease have had major design flaws. Most reports and guidelines on the treatment of hepatic bone disease have concluded that vitamin D deficiency does not have a significant pathogenetic role in the development of osteoporosis in cirrhosis, and that there is no evidence for a therapeutic effect of vitamin D supplementation. Conversely, it is generally recommended that patients with cirrhosis and low bone density should receive calcium and vitamin D supplementation; yet there is a paucity of reliable data on the optimal doses to use, as well as a lack of clearly demonstrated benefit. We believe that clinical trials of vitamin D therapy in these patients with liver disease are warranted. As low-dose oral supplementation often will not normalize vitamin D levels or suppress parathyroid hormone activity in cirrhotic patients, high-dose, parenteral vitamin D might be preferable, but further long-term studies are required to assess the benefits and safety of this approach.

A cretaceous supra-subduction oceanic basin source for Central Philippine ophiolitic basement complexes: Geological and geophysical constraints

Abstract: The Central Philippines is made up of several Cretaceous oceanic lithospheres that were generated and emplaced in a variety of geologic setting and manner. The Antique Ophiolite Complex exposed along the western side of Central Philippines is associated with blueschists, which suggests tectonic erosion accompanied subduction during its emplacement. Melanges are associated with the Southeast Bohol Ophiolite Complex and the Cebu ophiolitic rocks suggesting that subduction kneading was a major process during the emplacement of these oceanic fragments. The geology and geochemistry of the Tacloban Ophiolite Complex in Northern Leyte, the Malitbog Ophiolite Complex in Southern Leyte and the dismembered ophiolitic sequence in southern Samar imply that subduction played a role in the generation and emplacement of these Cretaceous oceanic lithospheres. Whole rock major and trace element, along with spinel mineral chemistry, favor a suprasubduction zone origin for these ophiolites. The ophiolites become younger towards the east (present-day geographic setting) indicating that convergence was accentuated by trench jumping. The similarities in the petrologic features, geochemical signatures and ages displayed by these oceanic lithosphere fragments in Central Philippines indicate that they were probably derived from a single Cretaceous oceanic basin which could have been a part of the proto-Philippine Sea Plate.

Metronidazole with Lactacyd vaginal gel in bacterial vaginosis

Abstract: Aim: To assess the efficacy and tolerability of lactic acid (Lactacyd vaginal gel; LVG) when given as an adjunct to metronidazole in the treatment of bacterial vaginosis (BV) among Filipino patients. Methods: A multicenter, open-labeled, controlled, randomized, three-arm comparative study on 90 women aged 18 years or over with clinically and microbiologically proven BV. Results: The lactobacilli colony count significantly increased over time in all three arms. At day 14, growth of lactobacilli was significantly higher among patients in the lactic acid gel and combination treatment arms. Significant reduction of malodorous vaginal discharge (whiff test) and lowest recurrence of BV were noted in the metronidazole plus lactic acid gel arm. Regarding disappearance of signs of BV, there was significant decrease in the pH level and frequency of clue cell positive patients across time but was not significantly different across treatment groups. Only one patient (3%, 1/60) among those who received lactic acid gel complained of increased curd-like discharge. Six patients (10%, 6/60) who received metronidazole complained of epigastric pain/discomfort, dizziness and dyspnea. Conclusions: Lactic acid gel (LVG) is safe and as efficacious as metronidazole in the treatment of BV. There is evidence that LVG when combined with metronidazole is superior to metronidazole alone in promoting lactobacilli colonization. LVG as an adjunct to metronidazole, having the least number of recurrent BV, appears to result in better long-term treatment effect on bacterial vaginosis.

Effect of spurious diffraction orders in arbitrary multifoci patterns produced via phase-only holograms.

Abstract: We analyze the effect of spurious diffraction orders when generating functional multifoci patterns produced by illuminating a phase-only hologram with a single Gaussian beam. Using a practical device for encoding a hologram generates an undesirable zero order and high-diffraction orders at the Fourier plane. This translates to the fact that a significant fraction of the incident light does not necessarily convert to functional multifoci patterns. In most applications, the zero order can be avoided by generating foci patterns shifted off the optical axis, which further increases the amount of light distributed to spurious high-diffraction orders owing to the reduction of light directed to the desired foci pattern. We analyze the amount of light dispersed to spurious orders and show that these unwanted orders can be a major limiting factor for most applications based on arbitrary multifoci patterns.

Prevalence and genetic diversity of Entamoeba histolytica in an institution for the mentally retarded in the Philippines

Abstract: A total of 113 mentally retarded patients residing in a mental institution in Metropolitan Manila, Philippines, were screened for the presence of Entamoeba histolytica based on microscopy and polymerase chain reaction (PCR). Anti-E. histolytica antibodies were also screened in 97 serum samples collected using immunofluorescence antibody (IFA) test. Parasitological examination showed E. histolytica/Entamoeba dispar in 43 cases (38.05%), while PCR detected 74 cases (65.48%) positive for E. histolytica and 6 cases (5.30%) positive for E. dispar. Interestingly, these 6 samples were coinfected with E. histolytica. IFA test revealed that 80.41% (78/97) of the respondents possessed significant antibody titers for intestinal infection of E. histolytica. Of this number, there were 5 patients negative in IFA test but positive in PCR. The genetic diversity of E. histolytica isolates was also investigated by analyzing polymorphism in the serine-rich gene by nested PCR on DNA directly extracted from stool specimens. A combination of the nested PCR results and the AluI digestion of the PCR products examined yielded six distinct DNA banding patterns among the 74 stool isolates. An apparent clustering of E. histolytica strains was observed in patients living in different residential cottages of the institution. These results indicate the high prevalence of E. histolytica in an institution for the mentally retarded in the Philippines.

Well-differentiated epithelial thyroid cancer management in the Asia Pacific region: A report and clinical practice guideline

Abstract: Context: Thyroid cancer is among the 10 most common malignancies in populations in the Asia Pacific region, where access to various relevant health care resources varies widely. Objective: An expert consensus conference was held to define regional patterns of practice and guidelines for optimal management of well-differentiated epithelial thyroid carcinomas. Results: Practice patterns vary from country to country, as would be anticipated form their variety of ethnic and racial populations, health care systems, economies, and cultures. Thyroid cancer care is provided by a number of medical and surgical specialists, usually including endocrinologists. The thyroid surgical skills, experience, and outcomes vary widely in the region. Radioiodine is available, to a greater or lesser extent, is almost all countries. Laboratory services for thyroid function monitoring are universally accessible; thyroglobulin assays are available in most countries. Recombinant thyrotropin is approved for use in only two countries...

Persistent pulmonary hypertension of the newborn: pathogenesis, etiology, and management.

Abstract: Persistent pulmonary hypertension of the newborn (PPHN) is characterized by severe hypoxemia shortly after birth, absence of cyanotic congenital heart disease, marked pulmonary hypertension, and vasoreactivity with extrapulmonary right-to-left shunting of blood across the ductus arteriosus and/or foramen ovale. In utero, a number of factors determine the normally high vascular resistance in the fetal pulmonary circulation, which results in a higher pulmonary compared with systemic vascular pressure. However, abnormal conditions may arise antenatally, during, or soon after birth resulting in the failure of the pulmonary vascular resistance to normally decrease as the circulation evolves from a fetal to a postnatal state. This results in cyanosis due to right-to-left shunting of blood across normally existing cardiovascular channels (foramen ovale or ductus arteriosus) secondary to high pulmonary versus systemic pressure. The diagnosis is made by characteristic lability in oxygenation of the infant, echocardiographic evidence of increased pulmonary pressure, with demonstrable shunts across the ductus arteriosus or foramen ovale, and the absence of cyanotic heart disease lesions. Management of the disease includes treatment of underlying causes, sedation and analgesia, maintenance of adequate systemic blood pressure, and ventilator and pharmacologic measures to increase pulmonary vasodilatation, decrease pulmonary vascular resistance, increase blood and tissue oxygenation, and normalize blood pH. Inhaled nitric oxide has been one of the latest measures to successfully treat PPHN and significantly reduce the need for extracorporeal membrane oxygenation.

Detection of Exposure to Environmental Pesticides During Pregnancy by the Analysis of Maternal Hair Using GC–MS

Abstract: Several classes of pesticides were extracted from maternal hair by solid-liquid extraction. Analysis of their selected metabolites involved a methanolic/hydrochloric acid methyl ester derivatization and liquid–liquid extraction. Gas chromatography electron impact mass spectrometry was used to detect and quantify the pesticides and metabolites. Recovery of parent compounds and metabolites from the analysis of spiked hair ranged from 87 to 112% with coefficients of variation less than 11%. Limits of detection ranged from 0.031 to 5.88 μg g−1. Analysis of hair samples from pregnant women in the Philippines showed maternal exposure during pregnancy to bioallethrin, propoxur, chlorpyrifos, pretilachlor and malathion.

Spawning and reproductive patterns of six exploited finfish species from the Arabian Sea, Sultanate of Oman

Abstract: Summary The spawning periods, sex ratio and length at first maturity were determined for six commercially important finfish species collected from Oman's industrial trawl fishery. During 1 year of monthly sampling, biological data were collected on 5586 fish. ancova was used to compare the length–weight relationships between sexes. There were sex-specific differences in length-weight relationships for three of the six species examined. One serranid, Epinephelus diacanthus, and a sparid, Pagellus affinis, had sex ratios significantly different from the expected ratio of 1 : 1. Size–frequency data revealed more male fish in the larger size classes for E. diacanthus, P. affinis and Nemipterus japonicus. Data on the development of female gonads and Gonado-somatic Index (GSI) revealed that the six species spawned at different times of the year. With the exception of female E. diacanthus, all fish had low GSI values during the onset of the summer monsoon period in June. The proportion of immature vs mature fish in the sample differed among species. For two species, Lethrinus nebulosus and Cheimerius nufar, more than 40% of the fish sampled (both sexes) were immature. Approximately 33% female and 41% male P. affinis were also immature. Management options such as temporal and area closures are discussed in light of the large number of immature fish caught by the fishery.

Fertility Decline, Family Structure, and Support for Older Persons in Latin America and Asia

Abstract: Objectives: To compare family structures and support for older persons in two Asian countries (Taiwan and the Philippines) and six urban areas in Latin America (Buenos Aires, Sao Paulo, Havana, Santiago, Mexico City, and Montevideo). Methods: Using the 1999 Survey of Health and Living Status of the Elderly in Taiwan, the 2000 Philippine Survey of the Near Elderly and Elderly, and the 2001 Pan American Health Organisation surveys on Salud, Bienestar y Envejecimiento en America Latina y el Caribe, descriptive tables show variations across countries in family structure, proximity, and transfers of support by the timing of the fertility transition in each location. Results: Older people in settings with earlier transitions had fewer children and more childlessness, higher levels of solitary living, and lower levels of coresidence with children. In earlier transition settings, receipt of family support was lower and provision higher. Discussion: The timing of the demographic transition has significant implicat...

Recent left‐oblique slip faulting in the central eastern Trans‐Mexican Volcanic Belt: Seismic hazard and geodynamic implications

Abstract: [1] Detailed structural analysis was conducted on the E-W trending Tenango Fault System (TFS) at the western end of the La Pera Fault System, a major structure within the Trans-Mexican Volcanic Belt (TMVB) Field mapping, which included trenching the fault trace, revealed the displacement of recent volcanic deposits The study indicates that the TFS is an active subvertical fault with transtensive left-lateral movement consistent with the contemporary stress regime in the region The estimated Holocene slip rate is 03–05 mm/yr The TFS activity constitutes an important seismic hazard in the intra-arc Lerma basin Several towns are located within this basin and are particularly vulnerable to seismic risk because of its underlying strata consisting of lacustrine and volcaniclastic deposits (estimated maximum Mw 68–7) The TFS is an important structural element in the complex tectonic deformation history of central eastern TMVB and influenced the behavior of recent volcanism within the Lerma basin

Phylogenetic analysis based on ITS sequences and conditions affecting the type of conidial germination of Bipolaris oryzae

Abstract: One taxonomic characteristic of Bipolaris species is the bipolar germination of conidia, but conidia of Bipolaris oryzae, the causal pathogen of brown spot in rice, are regularly observed to show intercalary germination, a characteristic of Drechslera species. The effect of selection, culture media and culture age on type of conidial germination was determined for three brown spot isolates from Cavinti, San Pablo and Palawan in the Philippines, obtained from infected leaves showing typical disease symptoms. Based on the analyses of their ITS1, ITS2 and 5·8S rDNA nucleotide sequences, the local isolates were clearly identified as B. oryzae. Selection for colonies of the three isolates derived from single conidia with either bipolar or intercalary germination had no effect on the number of spores showing bipolar germination in subsequent cultures. Germination on seven different culture media was tested; of these, rabbit food agar and water agar increased the percentage of bipolar germination of conidia, although this varied between isolates. Incubation of the cultures of all three isolates for longer periods prior to harvesting conidia increased the percentage of bipolar-germinating conidia from c. 40 to c. 90% with 5-day-old and 30-day-old cultures, respectively.

Breeding for Papaya ringspot virus resistance in Carica papaya via hybridisation with Vasconcellea quercifolia

Abstract: Papaya ringspot virus type P (PRSV-P) is a major threat to the papaya industry worldwide. F-1 hybrids have been produced when Carica papaya L. female flowers have been pollinated with pollen of the PRSV-P resistant species Vasconcellea quercifolia. F-1 plant production required embryo rescue 90 days post-pollination, and plantlet regeneration in vitro. Three hundred F-1 hybrids were grown to maturity in the field and had morphological characteristics that were identical to 1 or both parents, were intermediate between those of the parents, or were greater than either parent. They had a sex ratio of 2 ( male) : 49 ( hermaphrodite) : 49 ( female). Eighteen plants ( 7 male and 11 hermaphrodite) produced some viable pollen. Pollen viability of these plants as measured by germination on agar medium varied between 1.1 and 6.1% ( mean of 3.37 +/- 0.18) compared with > 90% for C. papaya. Cytogenetic studies showed limited homology between C. papaya and V. quercifolia genomes. The intergeneric hybrids varied in their reaction to strains of PRSV-P in Australia and the Philippines. Of the hybrids, 75% were resistant to PRSV- P while 25% produced virus symptoms.

A new species of Pseudodiaptomus (Crustacea: Copepoda: Calanoida) from the Philippines, with a key to pseudodiaptomids from the Philippines and comments on the status of the genus Schmackeria

Abstract: Four species of the demersal calanoid copepod genus Pseudodiaptomus were collected from Panay Island, Philippines in September 2003. They represented three species groups (sensu Walter 1986a): P. terazakii, a new species, and P. annandalei (Lobus group), P. bispinosus (Hyalinus group), and P. clevei (Nudus group). The female of the new species differs from its congeners in the possession of 3 pairs of anterolateral spines on the genital double-somite. The male is distinguished by the fifth leg right endopod, which is bifid at its apex, and the left non-bifid endopod. A key to the 14 pseudodiaptomid species known from the Philippines is provided herein. A review of the genus Schmackeria Poppe & Richard (1890) is presented, and all species attributed to this genus are merged into the genus Pseudodiaptomus. Because many new species of Pseudodiaptomus have been described recently, a revised key to the species-groups of Walter (1986a) is presented.

Antimalarial activity of crambescidin 800 and synthetic analogues against liver and blood stage of Plasmodium sp.

Abstract: Structural features associated with the antimalarial activity of the marine natural product crambescidin 800 were studied using synthetic analogues of the related compound ptilomycalin A. The study suggests that the guanidine moiety is cytotoxic, whereas the spermidine-containing aliphatic chain increases activity. The most active analogue, compound 11, had in vitro activity against Plasmodium falciparum strain 3D7 (IC50=490 nM) that was stronger than the in vitro activity against murine L5178Y cells (IC50=8.5~59 μM). In vitro growth inhibition of liver stages of P. yoelii yoelii in mouse hepatocytes was observed (IC50=9.2 μM). The compound did not significantly prolong median survival time after a single subcutaneous administration of 80 mg/kg in P. berghei-infected mice. Compound 11 did not cause DNA fragmentation in an in vitro micronucleus assay.