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At least 19 recordsLinked to original sources
PubMed2000

Molecular cloning and characterization of a midgut chymotrypsin-like enzyme from the lesser grain borer, Rhyzopertha dominica.

A cDNA encoding a chymotrypsinogen-like protein in midguts of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) was cloned and sequenced. The 901 bp cDNA contains an 816-nucleotide open reading frame encoding 272-amino acids. The predicted molecular mass and pI of the mature enzyme are 23.7 kDa and 4.64, respectively. The encoded protein includes amino acid sequence motifs that are conserved with 5 homologous chymotrypsinogen proteins from other insects. Features of the putative chymotrypsin-like protein from R. dominica include the serine proteinase active site (His(90), Asp(133), Ser(226)), conserved cysteine residues for disulfide bridges, the residues (Gly(220), Gly(243), Asp(252)) that determine chymotrypsin specificity, and both zymogen activation and signal peptides. A TPCK-sensitive caseinolytic protein (P6) with an estimated molecular mass of 24 kDa is present in midgut extracts of R. dominica and can be resolved by electrophoresis on 4-16% polyacrylamide gels. The molecular mass of this caseinolytic enzyme is similar to that of the chymotrypsin deduced from cDNA. Midgut extracts of R. dominica readily hydrolyzed azocasein and N-succinyl-alanine-alanine-proline-phenylalanine-p- nitroanilide (SAAPFpNA), a chymotrypsin-specific substrate. Properties of the enzymes responsible for these activities were partially characterized with respect to distribution in the gut, optimum pH, and sensitivity toward selected proteinase inhibitors. Optimal activity against both azocasein and SAAPFpNA occurs in a broad pH range from about 7 to 10. Both azocasein and SAAPFpNA activities, located primarily in the anterior midgut region, are inhibited by aprotinin, phenylmethyl sulphonylfluoride (PMSF), and soybean trypsin inhibitor (STI). TPCK (N-alpha-tosyl-L-phenylalanine chloromethyl ketone) and chymostatin inhibited more than 60% of SAAPFpNA but only about 10-20% of azocasein activity. These results provide additional evidence for the presence of serine proteinases, including chymotrypsin, in midguts of R. dominica. Arch. Insect Biochem. Physiol. 43:173-184, 2000.Published 2000 Wiley-Liss, Inc.

Amino Acid Sequence↗
PubMed1999

Characterization of midgut trypsin-like enzymes and three trypsinogen cDNAs from the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrichidae).

Protein digestion in the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), results from the action of a complex of serine proteinases present in the midgut. In this study we partially characterized trypsin-like enzyme activity against N-alpha-benzoyl-L-arginine p-nitroanilide (BApNA) in midgut preparations and cloned and sequenced three cDNAs for trypsinogen-like proteins. BApNAase activity in R. dominica midgut was significantly reduced by serine proteinase inhibitors and specific inhibitors of trypsin, whereas BApNAase activity was not sensitive to specific inhibitors of chymotrypsin or aspartic proteinases. However, trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E-64) inhibited BApNAase activity by about 30%. BApNAase was most active in a broad pH range from about pH 7 to 9.5. The gut of R. dominica is a tubular tract approximately 2.5 mm in length. BApNAase activity was primarily located in the midgut region with about 1.5-fold more BApNAase activity in the anterior region compared to that in the posterior region. Proteinases with apparent molecular masses of 23-24 kDa that were visualized on casein zymograms following electrophoresis were inhibited by TLCK. Three cDNAs for trypsinogen-like proteins were cloned and sequenced from mRNA of R. dominica midgut. The full cDNA sequences consisted of open reading frames encoding 249, 293, and 255 amino acid residues for RdoT1, RdoT2, and RdoT3, respectively. cDNAs RdoT1, RdoT2, and RdoT3 shared 77-81% sequence identity. The three encoded trypsinogens shared 54-62% identity in their amino acid sequences and had 16-18 residues of signal peptides and 12-15 residues of activation peptides. The three predicted mature trypsin-like enzymes had molecular masses of 23.1, 28, and 23.8 kDa for RdoT1, RdoT2, and RdoT3, respectively. Typical features of these trypsin-like enzymes included the conserved N-terminal residues IVGG62-65, the catalytic amino acid triad of serine proteinase active sites (His109, Asp156, Ser257), three pairs of conserved cysteine residues for disulfide bridges, and the three residues (Asp251, Gly274, Gly284) that determine specificity in trypsin-like enzymes. In addition, RdoT2 has both a PEST-like sequence at the C-terminus and a free Cys158 near the active site, suggesting instability of this enzyme and/or sensitivity to thiol reagents. The sequences have been deposited in GenBank database (accession numbers AF130840 for RdoT1, AF130841 for RdoT2, and AF130842 for RdoT3).

Amino Acid Sequence↗
PubMed2000

Attitudes towards mental illness in the Commonwealth of Dominica.

Little is known about the perception of mental illness in the English-speaking Caribbean. This study was conducted in 1995 to determine the attitudes, knowledge, and help-seeking practices for emotional disorders in the Commonwealth of Dominica. Two groups in Dominica were surveyed: 67 community leaders, consisting of nurses, teachers, and police officers; and 135 community members grouped into five socioeconomic strata that were collapsed to three for the analysis. All the respondents were asked to identify and suggest management of individuals with psychosis, alcoholism, depression, and childhood hyperactivity, as depicted in case vignettes. The person in the psychosis vignette was diagnosed as suffering from mental illness by 84.0% of the leaders and by 71.2% of the community members. However, in each of the three other vignettes, fewer than 30% of the respondents thought that mental illness was present. The person with alcoholism was viewed as having a serious problem by only slightly more than half of the respondents. Fewer than half of the respondents thought that the individuals with depression or hyperactivity had serious problems. The community leaders did somewhat worse in recognizing mental illness than did the community members. Respondents were most likely to refer a family member with emotional problems to a medical practitioner. In conclusion, education about mental health problems is needed in Dominica. Especially disconcerting was the lack of knowledge on mental illness among nurses, teachers, and police officers, that is, professionals directly involved in the pathway to care.

Adult↗
PubMed2002

The response of phosphine-resistant lesser grain borer Rhyzopertha dominica and rice weevil Sitophilus oryzae in mixed-age cultures to varying concentrations of phosphine.

The response of Rhyzopertha dominica and Sitophilus oryzae (both phosphine-resistant) in mixed-age cultures to phosphine at fixed concentration-time products (CT) of 10,500 to 168,000 microliters litre 1 h (ppm h) with either constant, rising or falling concentrations for 7 days was studied at 27 (+/- 2) degrees C. At lower CT products, rising concentrations of phosphine led to significantly fewer survivors of R dominica and S oryzae. Conversely, exposure to falling concentrations of phosphine resulted in significantly more survivors. The influence of changing concentrations of phosphine was more pronounced in S oryzae than in R dominica. In the latter, at the lower CT products of 21,000 and 42,000 microliters-1 h, the adult stage proved to be most tolerant, contrary to the accepted belief that the egg or pupal stage are always more tolerant to phosphine. The results indicate that application of phosphine in rising concentrations is more effective than in constant or falling concentrations.

Animals↗
PubMed1998

The use of capture-recapture methods to monitor diabetes in Dominica, West Indies.

The aim of this project was to evaluate the utility of capture-recapture (CR) estimation methodology, together with easily accessible sources of information, for monitoring the frequency of diabetes mellitus in a developing country. On the Caribbean island of Dominica, from July 1995 through July 1996, the names were collected of all individuals who were listed in at least one of three sources as having been diagnosed with diabetes during 1995. The sources were the membership list of the Dominica Diabetic Association, a register of patients in seven regional health centers, and clinic records of the Princess Margaret Hospital, which is the main hospital on the island. Capture-recapture techniques were used to estimate the number of Dominicans with diagnosed diabetes who were missed by all three sources of information and to evaluate dependencies among the sources. An ascertainment-corrected prevalence estimate of diagnosed diabetes was then calculated. The three sources identified a total of 1,945 different individuals. When this number was compared with the ascertainment-corrected estimate obtained with CR methodology (2,688), it appeared to represent only 72.3% of the true prevalence of diagnosed diabetes. Most of the under-ascertainment by the data sources was due to cases that were missed in the urban area of the island. This approach to disease monitoring may be useful for other Caribbean countries. However, standardized procedures for collecting and reporting prevalence and morbidity data are needed to maximize its accuracy and cost-effectiveness.

Chi-Square Distribution↗
PubMed2002

Genetic linkage analysis of the lesser grain borer Rhyzopertha dominica identifies two loci that confer high-level resistance to the fumigant phosphine.

High levels of inheritable resistance to phosphine in Rhyzopertha dominica have recently been detected in Australia and in an effort to isolate the genes responsible for resistance we have used random amplified DNA fingerprinting (RAF) to produce a genetic linkage map of R. dominica. The map consists of 94 dominant DNA markers with an average distance between markers of 4.6 cM and defines nine linkage groups with a total recombination distance of 390.1 cM. We have identified two loci that are responsible for high-level resistance. One provides approximately 50x resistance to phosphine while the other provides 12.5x resistance and in combination, the two genes act synergistically to provide a resistance level 250x greater than that of fully susceptible beetles. The haploid genome size has been determined to be 4.76 x 10(8) bp, resulting in an average physical distance of 1.2 Mbp per map unit. No recombination has been observed between either of the two resistance loci and their adjacent DNA markers in a population of 44 fully resistant F5 individuals, which indicates that the genes are likely to reside within 0.91 cM (1.1 Mbp) of the DNA markers.

Animals↗
PubMed1977

Studies on the functional morphology and ecology of the atyid prawns of Dominica.

Six species of atyid prawns, representing five genera, occur in streams on the West Indian island of Dominica (figures 1-6). The ecology and habits of each are described and the relation of features of gross morphology to ways of life noted. Xiphocaris elongata, the most primitive living atyid, is a lightly built prawn whose adult habits are related to life in quiet pools in streams. An agile species and an excellent swimmer, it picks up individual small food particles with specialized chelipeds (figures 18 and 19) that differ from those of all other atyids and manipulates them with mouthparts (figure 77) which, while highly complex, are more primitive than those described for any other member of the family. Atya innocous and A. scabra, representing perhaps the most specialized atyid genus, are very similar in gross morphology and are robustly built ambulatory species. A. innocous is common in a variety of situations: A. scabra is rare and has been found only in fast-flowing water. Both have chelipeds whose three distal segments are extremely specialized (figure 36) and whose propus and dactylus are armed with an exceedingly complex array of long, slender bristles. These can be used either as brushes for collecting finely particulate detritus (figures 58-60) or as filtering fans (figures 68 and 69) which, held passively in flowing water, extract suspended particles. The Atyidae is unique among the Malacostraca in having representatives that filter passively by means of the chelipeds. The bristles (figure 40) are extended (figure 49), not by muscles, of which there are none in the distal parts of the propus and none anywhere in the dactylus, but by hydraulic forces. The return of the bristles to rest is by means of a cuticular spring. Some of the bristles of A. innocous are armed distally with minute denticles (figures 41 and 42) that facilitate scraping and sweeping: no such are present in A. scabra. The difference is related to the relative importance of scraping in the two species: A. innocous scrapes frequently, A. scabra seldom. Finely particulate food is transferred and manipulated by the extremely complex oral machinery (figure 78). One of the most elaborate parts of this is a teaselling device in which components of the maxillae and first maxillipeds participate (figures 80 and 81). The feeding mechanism is described. Morphologically and functionally Micratya poeyi can be regarded as a miniature version of Atya. It can both sweep and filter. Potimirim glabra is rare in Dominica and its habits but little known. Morphologically it is similar to, but more primitive than, Micratya. Its cheliped bristles are clearly specialized for sweeping and show few signs of being used for passive filtration. Jonga serrei occupies a separate and well-defined niche in the quieter parts of streams. For this it shows many morphological specializations and lacks such attributes as stout claws and robust walking legs that are the hallmark of its relatives living in fast-flowing waters.

Animals↗
PubMed1990

The dental health of 12-year-old children in Dominica: a report of a survey using WHO methods.

As part of the process of assisting in the planning of a primary dental health care system in the Commonwealth of Dominica, we conducted a survey of mostly 12-year-old children. The purpose of the survey was to assess the oral health status and identify the needs for treatment and prevention. Secondary purposes included training Dominican dental auxiliaries and assistants to collect epidemiologic data and to use the findings to compare oral health status by region and previous coverage by the auxiliaries. The sample was obtained from schools throughout the country. Examinations were conducted according to standard WHO methods, using mirrors and explorers. The findings were recorded on prepared forms and the data were processed in Toronto using microcomputers. We found 31% of children to be caries-free and the mean DMFT score to be 2.5 (95% CI 2.2-2.7). Only 8% of lesions had been treated. No differences were observed by region but in areas covered by dental auxiliaries, children had fewer decayed teeth, fewer DMFT and higher F/DMFT ratios. Only 17% scored 0 on the CPITN index and 63% scored 2, meaning they had calculus. Debris was 3.6 times more likely to be found among those with gingival bleeding or calculus compared to those with periodontal health. Single surface restorations made up 82% of the estimated 2.0 caries treatment services required. The survey findings will allow planners to design specific preventive and treatment programs to meet Dominica's needs.

Analysis of Variance↗
PubMed1998

District nursing in Dominica.

District nurses constitute the basis of the primary health care services in Dominica. All encounters of three district nurses were registered using the international classification of primary care. Information on other aspects of district nursing was collected by participating observation and the use of a questionnaire. Check-ups for hypertension, diabetes, pregnancy and immunisations constituted 40% of all reasons for encounter. The district nurses dealt with 80% of all contacts; only 20% of all patients were referred to the district medical officer. There are several discouragements to the motivation of the nurses. In addition to being a nurse, all have their family and other obligations. Postgraduate training with diversified certification and upgrading of wages could contribute to a continued high motivation and increased job satisfaction.

Adolescent↗
PubMed1999

Health status of the elderly in the Marigot Health District, Dominica.

The health status and the prevalence of hypertension, diabetes mellitus, glaucoma and visual disorders of 123 elderly people (56 men, 67 women) in the Marigot Health District, Dominica, were assessed by means of four questionnaires; collection of data from their medical records; physical examination, measurement of blood pressure, visual acuity and intra-ocular pressure (IOP); and testing for glucosuria. The overall health status was good, but 20% were dependent on care. 74% were independent in the activities in daily life, with only moderate limitations in activities. The health status decreased considerably in those over 75 years of age. There were slight perceived differences in health status between men and women. About 40% of the study population were known to be hypertensive, and another 13% had an elevated blood pressure on examination. Diabetes mellitus was present in 15%. 20% had a visual acuity of 0.1 or below, and 10% had an elevated IOP. During the study, a considerable number of new cases of hypertension, diabetes mellitus and elevated IOP were diagnosed. 50% of the study population who were on medication used this more than as prescribed. This study indicates a high prevalence of the secondary complications of hypertension, diabetes mellitus, cataract, glaucoma and osteo-arthritis that cause disability and dependency in the elderly population. Education, diagnosis at an early stage and appropriate treatment of these disorders may prevent or delay their development. We sugggest the development of a programme oriented approach of primary health care for the elderly to support this.

Activities of Daily Living↗
PubMed2002

Internalized racism, body fat distribution, and abnormal fasting glucose among African-Caribbean women in Dominica, West Indies.

The current study examined the relationship of internalized racism to glucose intolerance in a population of Afro-Caribbean women aged 18 to 55. Also of interest was whether this relationship would be differentially influenced by the type of body fat distribution or confounded by the level of hostility. A total of 244 women were selected from a systematic sample of households on the island of Dominica, West Indies. Demographic data together with information on internalized racism were collected by questionnaire. Anthropometric information and fasting blood glucose were also measured. Women with high levels of internalized racism exhibited an increased risk of elevated fasting glucose compared to those with low levels of internalized racism (odds ratio (OR) = 2.4; 95% confidence interval (CI) = 1.1-5.5). There was no difference in mean body mass index (BMI) by level of internalized racism. However those with high internalized racism had a significantly larger waist circumference after adjusting for age, education, hostility, and elevated fasting glucose status. In multivariate analyses controlling for age, education, hostility, and either weight or BMI, internalized racism remained independently associated with elevated fasting glucose. However, once waist circumference was included in the model, the relationship of internalized racism to elevated fasting glucose was not statistically significant. This study demonstrates a significant relationship between internalized racism and abnormal levels of fasting glucose which may be mediated through abdominal fat. The exact nature of the relationship of internalized racism to glucose intolerance may be an important area of future study.

Adolescent↗
PubMed2001

The action of phosphine against the eggs of phosphine-resistant and -susceptible strains of Rhyzopertha dominica F.

The effect of phosphine at exposure periods of 24, 48 and 120 h on hatching and mortality of 0- to 1-day-old eggs of susceptible (TN6) and resistant (FC10) strains of Rhyzopertha dominica of field origin was investigated. The fumigant affected hatching in both the strains. In a 48-h exposure at 27 (+/- 2) degrees C, the LD99 doses for the eggs of TN6 and FC10 were 0.56 and 3.25 mg litre-1, respectively. Significant reduction in hatching was observed in treated batches with progressive increase of phosphine dose in the first 2-3 days. On subsequent days the numbers hatching were often similar to those in controls, and sometimes exceeded control hatch, especially following a 5-day exposure. A critical change in the order of susceptibility of egg and adult stages of the two strains was noticed. In 48-h exposures, eggs of the susceptible strain were more tolerant than their adults, whilst the reverse was true in the resistant strain.

Animals↗
PubMed1987

A comparison of some effects of phosphine, hydrogen cyanide and anoxia in the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae).

The effects of phosphine, hydrogen cyanide and anoxia on levels of ATP, pyruvate and lactate in Rhyzopertha dominica are compared. The effect of phosphine on anaerobiosis is not directly comparable either with HCN or anoxia. Reduction of catalase by feeding 3 amino 1,2,4 triazole does not enhance the toxicity of phosphine in treated insects.

Adenosine Triphosphate↗
PubMed1998

Characterization of acetylcholinesterase purified from the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrichidae).

Acetylcholinesterase (AChE, EC 3.1.1.7) purified from the lesser grain borer (Rhyzopertha dominica) was significantly inhibited by higher concentrations of the substrates acetylthiocholine (ATC), acetyl-(beta-methyl) thiocholine (A beta MTC) and propionylthiocholine (PTC). 2. The efficiency of AChE for hydrolyzing different substrates was ATC > A beta MTC > PTC > S-butyrylthiocholine. The enzyme activity was completely inhibited by 10(-5) M eserine or BW284C51, but was only partially inhibited by ethopropazine at the same concentration. These results confirmed that the purified enzyme was an typical insect AChE. 3. Non-denaturing and SDS polyacrylamide gel electrophoresis (PAGE) showed only one major molecular form in the purified AChE with a molecular weight of about 107,000 prior to reduction and about 56,000 after reduction, suggesting the homodimer of AChE linked with disulfide bonds.

Acetylcholinesterase↗
PubMed2002

QSAR evaluation of cyanohydrins' fumigation toxicity to house fly (Musca domestica) and lesser grain borer (Rhyzopertha dominica).

Using fumigation toxicity data of 11 natural and synthetic cyanohydrins to house fly (Musca domestica) and a stored-product pest, the lesser grain borer (Rhyzopertha dominica), the quantitative structure-activity relationships (QSAR) of cyanohydrins were examined by Oxford Molecular CAChe 3.2 and Microsoft Excel. This analysis used eight physicochemical parameters. Correlation between the LC(50) values for house fly and lesser grain borers was also evaluated. The results showed that log P, polarizability, and molar refractivity are the best descriptors to explain the relationship between the structure of cyanohydrins and biological effects in house flies, and to a lesser degree in lesser grain borers. A significant relationship was also found between the toxicity to house flies and lesser grain borers.

Animals↗
PubMed2002

Pyrethroid-Acarophenax lacunatus interaction in suppressing the beetle Rhyzopertha dominica on stored wheat.

Any biocontrol agent used against stored grain insects will have to interact with insecticides used as grain protectants due to their heavy use especially in tropical areas. Therefore, the interaction between the pyrethroid insecticides bifenthrin and deltamethrin and Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae), an egg parasite of the stored cereal pest Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), was assessed in a range of mite densities and insecticide doses for each compound. Despite the mite species presence on all insecticide doses, the lowest instantaneous rate of increase of A. lacanatus was recorded with the highest doses of insecticides. The presence of the biological control agent at all doses of both insecticides suggests its tolerance to these compounds. A. lacunatus showed higher parasitism rate with bifenthrin than with deltamethrin indicating a higher selectivity of the first compound to the biocontrol agent.

Animals↗
PubMed2002

Genetics of resistance to phosphine in Rhyzopertha dominica (Coleoptera: Bostrichidae).

The inheritance of resistance to phosphine was studied in two strains of the lesser grain borer, Rhyzopertha dominica (F.), labeled 'Weak-R' and 'Strong-R'. These strains were purified versions of field-selected populations collected in Queensland, Australia. Weak-R and Strong-R were, respectively, 23.4 times (20-h exposure) and 600 times (48-h exposure) resistant to phosphine compared with a reference susceptible strain (S-strain). Each -R strain was crossed with the S-strain and the response to phosphine was measured in their respective F1, F2, and F1-backcross (F1-BC) progenies. Data from testing of reciprocal F1 progeny indicated that resistance in Weak-R was autosomal and incompletely recessive with a degree of dominance -0.96. Modified chi-square analysis and contingency analysis of the observed response to phosphine of F1-BC and F2 progenies rejected the hypothesis of single gene inheritance of resistance. Analysis of the response of the F1, F2, and F1-BC progeny from the Strong-R x S-strain cross also rejected the null hypothesis for single gene resistance. Resistance in the Strong-R strain was autosomal and incompletely recessive with a degree of dominance of -0.64. The Weak-R and Strong-R strains were then crossed. Analysis ofthe F1 and F2 progenies of this reciprocal cross revealed that the strong resistance phenotype was coded by a combination of the genes already present in the Weak-R genotype plus an extra major, incompletely recessive gene. There was also evidence of a minor dominant gene present in approximately 5% of Strong-R individuals.

Animals↗
PubMed1992

Obstetrical condition and neonatal neurological outcome in Dominica, the Caribbean. A comparative study.

Risk factors during pregnancy and delivery and neurological morbidity of newborns were assessed in a birth cohort in Dominica, the Caribbean. The data were compared with two reference groups, one from Grenada, the Caribbean, and the other from Groningen, the Netherlands. Despite variations in cultural and socio-economic situation, the similarities in obstetrical conditions, neonatal neurological morbidity and perinatal relationships between the three groups were more striking than the differences. The Dominican group showed a significantly higher rate of preterm births than the two other groups. Preterm birth was associated with a significant increase in neurological deviancy. In general motility and muscle tone were found to be lower in the Caribbean region than in the Netherlands.

Apgar Score↗