Genes expressed in Brugia malayi infective third stage larvae

We have used a tag sequencing approach to survey genes expressed in the third stage infective larvae of the human filarial nematode parasite Brugia malayi. RNA was isolated from late vector-stage L3 larvae after days 9 or 10 of infection in mosquitos, and converted to cDNA by reverse transcriptase. Double-stranded cDNA was produced by either conventional methods (non-SL cDNA library) or by PCR using the nematode spliced leader (SLI) and oligo(dT) primers (SL cDNA library). Two clone libraries (one from SL and one from non-SL cDNAs) were constructed in lambda ZapII. A set of these full-length clones was selected and 596 inserts were sequenced from the 5' end. We have identified 364 B. malayi genes (the majority of which are new) that encode housekeeping proteins, structural proteins, proteins of immediate immunological or drug-discovery interest as well as a large class of novel sequences which may prove to have significant involvement in host invasion. Extensive, genome-wide approaches to the analysis of larval gene expression are now possible for B. malayi. We present several examples of this approach.

A polymerase chain reaction assay for detection of the parasite Wuchereria bancrofti in human blood samples

To identify Wuchereria bancrofti DNA sequences that could be used as the basis for a simple and rapid parasite detection assay, a genomic library of W. bancrofti was constructed and screened for highly repeated DNA. The repeat found with the highest copy number was 195 basepairs (bps) long, 77% AT, and 300 copies per haploid genome. This sequence was designated the Ssp I repeat because it has a unique recognition site for that restriction endonuclease in all or most of the repeat copies. The Ssp I repeat DNA family is dispersed, genus-specific, and exists in all of the different geographic isolates of W. bancrofti tested. Based on DNA sequence analysis of this repeat, we have developed an assay to detect very small quantities of W. bancrofti DNA using the polymerase chain reaction (PCR). With this PCR assay, the Ssp I repeat was detected in as little as 1 pg of w. bancrofti genomic DNA (about 1% of the DNA in one microfilaria) added to 100 microliters of human blood. The PCR assay also amplified Ssp I repeat DNA from geographic isolates of W. bancrofti from around the world but not from other species of filariae or from human or mosquito DNA. Microfilaria-positive human blood samples collected in Mauke, Cook Islands were shown to be Ssp I PCR-positive, while microfilaria-negative samples were PCR-negative. The specificity and sensitivity of the Ssp I PCR assay indicates that this approach has significant potential for improved screening of large human populations for active W. bancrofti infection.

Passage of a delta-opioid receptor selective enkephalin, [D-penicillamine2,5] enkephalin, across the blood-brain and the blood-cerebrospinal fluid barriers

[D-Penicillamine2,5] enkephalin (DPDPE) is an enzymatically stable, delta-opioid receptor-selective peptide, which produces analgesia when given intracerebroventricularly. However, because only modest analgesic effects were seen after subcutaneous administration of DPDPE, it has been inferred that it does not cross the blood-brain barrier well. In this present study, a vascular brain perfusion technique in anesthetized rats was used to measure directly whether [3H]DPDPE could cross the blood-brain and/or the blood-CSF barriers. The results indicated that the brain uptake of [3H]DPDPE was significantly greater than that of [14C]sucrose, a vascular marker (p < 0.01), and than that of [3H]DPDPE into the CSF (p < 0.01). Furthermore, HPLC analysis confirmed the integrity of the 3H to DPDPE and demonstrated that intact [3H]DPDPE entered the brain. Although 1 mM leucine-enkephalin failed to inhibit uptake of [3H]DPDPE, unlabeled DPDPE (100 microM) caused a significant inhibition of the brain uptake (p < 0.01) but not the CSF uptake of [3H]DPDPE. These data provide evidence that intact [3H]DPDPE enters the CNS of anesthetized rats by saturable and nonsaturable mechanisms. In addition, the saturable mechanism is likely to be found at the blood-brain barrier, with the blood-CSF barrier playing only a minor role in the brain uptake of this peptide.

Blood-to-central nervous system entry and stability of biphalin, a unique double-enkephalin analog, and its halogenated derivatives

Biphalin (Tyr-D-Ala-Gly-Phe-NH)2 is a unique opioid peptide analog that contains two active enkephalin pharmacophores and is more potent than morphine and etorphine in eliciting analgesia after intrathecal administration. After systemic administration, only a small amount was detected in the brain, but analgesia was observed. Because halogenation of enkephalin analogs has been shown to increase the brain uptake after systemic administration, our research group synthesized both p-[Cl-Phe4,4']biphalin and p-[F-Phe4,4']biphalin. The aim of the present study was to characterize and compare the blood-to-central nervous system (CNS) pharmacokinetics and biological stability of biphalin and related halogenated analogs. The initial screening used an in vitro blood-brain barrier model and identified p-[Cl-Phe4,4')biphalin as the enkephalin analog with the best potential for greater CNS entry. The CNS uptake and stability of biphalin and p-[Cl-Phe4,4']biphalin was examined further using an in situ brain perfusion technique coupled to high-performance liquid chromatography analysis. Both biphalin and its chlorohalogenated analog, were found to significantly enter the CNS through both the blood-brain and blood-cerebrospinal fluid barriers. Chlorohalogenation of biphalin was shown to both improve CNS entry, most likely through an enhancement in lipophilicity, and increase biological stability. This study suggests that incorporation of chlorohalogens at the p-Phe4,4' position is a promising structural modification in the development of biphalin as a successful opioid drug for the clinic.

Oral health and health related behaviours among three-year-old children born to first and second generation Pakistani mothers in Bradford, UK

Many young Muslim children whose families originated from the Indian sub-continent have poorer levels of oral health than their indigenous White peers, but it is unclear whether and to what extent subsequent generations may be similarly disadvantaged. This study aimed to compare dental health and associated behavioural attributes among United Kingdom-born three-year-old children of first and second generation Pakistani Muslim mothers resident in areas of social deprivation in Bradford, West Yorkshire. Multi-lingual interviews completed a home-based, semi-structured questionnaire, and a dental examination was conducted at a subsequent visit on 226 children, 117 with Pakistan-born mothers and 109 born in the UK. When the two generation groups were compared, no differences were observed in infant feeding practices, oral hygiene routines or dental attendance patterns, in mothers' attendance at ante-natal classes, or their knowledge of caries prevention. However, a higher proportion of UK-born mothers were able to speak English and reported that they had attended a dentist themselves, had received advice there, and were better informed of categories exempt from dental charges. A 24-hour retrospective qualitative dietary recall indicated that children of UK-born mothers consumed, on average, more frequent intakes of foods classified in the 'bread and cereal' group and of sweet drinks at meal times. While there were no significant differences in the proportion who were cavity free, children of UK-born mothers had higher mean caries experience (dmft=2.30) compared with those of Pakistan-born mothers (dmft=1.38). It was concluded that the total burden of dental caries experience among a subsequent generation of Pakistani children was higher than that of the previous generation. Poor dental health is likely to remain a challenge in this community for the foreseeable future.

The biological activity of the corticotropin-releasing hormone receptor-adenylate cyclase complex in human myometrium is reduced at the end of pregnancy

We recently suggested that placentally derived CRH might influence human parturition via specific receptor mechanisms. We identified a human myometrial CRH receptor that changes to a high affinity state in the later stages of pregnancy and becomes coupled to the adenylate cyclase system. The purpose of this study was to investigate the functional capacity of this receptor in myometrial tissue obtained from women being delivered electively by cesarian section at term (38-40 weeks gestation) and preterm (30-35 weeks gestation) before the onset of labor. Myometrial membrane suspensions were prepared by differential centrifugation, and the production of cAMP after stimulation with various test substances was measured by RIA. In preterm myometrium, both human CRH and cholera toxin stimulated cAMP production. This effect was significantly reduced in term myometrium. The adenylate cyclase was functionally active in term myometrium, as demonstrated by the use of forskolin. Furthermore, pertussis toxin pretreatment of term myometrial membranes did not increase the response to CRH. These results suggest that in human pregnant myometrium at term, there is a modification in the coupling mechanisms between CRH receptors and the catalytic component of adenylate cyclase, resulting in a reduction of CRH-stimulated cAMP production.

Chitinase genes expressed by infective larvae of the filarial nematodes, Acanthocheilonema viteae and Onchocerca volvulus

State-specific products of 220 and 75 kDa were identified by metabolic labelling of infective larvae of the filarial nematode Acanthocheilonema viteae in ticks. Synthesis was temperature sensitive, occurring at 27 degrees C but not at 37 degrees C. These products were secreted 3-6 days after leaving the vector during post-infective development, but subsequent expression was not detected. The smaller protein with a pI of 6.2, was purified by two-dimensional electrophoresis and the N-terminal amino acid sequence was derived. This provisionally identified the protein as a chitinase, which was confirmed biochemically by glycol-chitin substrate gel electrophoresis. The polymerase chain reaction was used to amplify a product from a cDNA library of A. viteae infective larvae. The nucleotide sequence codes for a putative signal peptide of 20 amino acids and a mature protein of 504 residues (Mr 56 kDa), exhibiting 69% identity (81% similarity allowing for conservative substitutions) with the MF1 chitinase described from microfilariae of Brugia malayi. N-linked glycosylation may account for some, or all, of the discrepancy in Mr between the predicted polypeptide and the native parasite product (75 kDa). Primers based on the A. viteae sequence were used to amplify a related sequence from a cDNA library of Onchocerca volvulus infective larvae. The O. volvulus cDNA codes for a 20-amino acid signal peptide followed by 477 residues with an Mr of 54 kDa, and shares 67% identity with the A. viteae chitinase (80% similarity allowing for conservative substitutions) and 69% identity with the B. malayi MF1 molecule. It is proposed that chitinases expressed by infective stages of these filarial nematodes may play a role in ecdysis during post-infective development.

Absence of effect of sertraline on the pharmacokinetics and pharmacodynamics of phenytoin

A double-blind, randomized, placebo-controlled study assessed the effects of sertraline on the pharmacokinetics and pharmacodynamics of phenytoin in 30 healthy male volunteers.

METHOD

All subjects received phenytoin throughout the study. The dose of phenytoin was 100 mg three times daily; steady-state trough plasma phenytoin concentrations were determined on Day 6. Concurrent treatment with sertraline (16 subjects) or placebo (13 subjects) was initiated on Day 8 and continued throughout the study in those subjects whose trough plasma phenytoin concentrations were between 5 and 20 micrograms/mL. The dose of sertraline was increased from 50 to 200 mg/day over 7 days; the 200-mg dose was then administered for 10 days. The plasma phenytoin concentration-time profile was determined on Day 7 before the start of sertraline or placebo dosing and at the end of dosing on Day 24. Psychometric testing was done before and after dosing on Days 0, 7, and 24.

RESULTS

There were no significant differences between the sertraline group and the placebo group in the pharmacokinetic parameters of phenytoin. In addition, there was no indication that administration of phenytoin alone or concomitant administration of phenytoin and sertraline impaired cognitive function. Treatment-related side effects, primarily headache and nausea, were reported in 8 of 16 sertraline subjects and in 5 of 13 placebo subjects. Two subjects in the sertraline group withdrew because of side effects (rash), and 3 subjects in the placebo group withdrew because of side effects (rash and headache).

CONCLUSION

High dosages of setraline did not affect the pharmacokinetics or the pharmacodynamics of phenytoin in ths study performed in healthy volunteers.

Absence of effect of sertraline on time-based sensitization of cognitive impairment with haloperidol

This double-blind, randomized, placebo-controlled study evaluated the effects of haloperidol alone and haloperidol plus sertraline on cognitive and psychomotor function in 24 healthy male subjects.

METHOD

All subjects received placebo on Day 1 and haloperidol 2 mg on Days 2 and 25. From Days 9 to 25, subjects were randomly assigned to either sertraline (12 subjects) or placebo (12 subjects); the sertraline dose was titrated from 50 to 200 mg/day from Days 9 to 16, and remained at 200 mg/day for the final 10 days of the drug administration period. Cognitive function testing was performed before dosing and over a 24-hour period after dosing on Days 1, 2, and 25.

RESULTS

Impairment of cognitive function was observed 6 to 8 hours after administration of haloperidol on Day 2 but was not evident 23 hours after dosing. When single-dose haloperidol was given again 25 days later, greater impairment with earlier onset was noted in several tests in both treatment groups, suggesting enhancement of this effect. There was no indication that sertraline exacerbated the impairment produced by haloperidol since an equivalent effect also occurred in the placebo group. Three subjects (2 on sertraline and 1 on placebo) withdrew from the study because of side effects. Ten subjects in each group reported side effects related to treatment. The side effect profiles of sertraline and of placebo were similar.

CONCLUSION

Haloperidol produced a clear profile of cognitive impairment that was not worsened by concomitant sertraline administration.

Absence of a sertraline-mediated effect on the pharmacokinetics and pharmacodynamics of carbamazepine

A double-blind, randomized, placebo-controlled study was conducted in 14 healthy male volunteers to assess the effects of sertraline on the pharmacokinetics and pharmacodynamics of carbamazepine.

METHOD

Subjects received carbamazepine 200 mg once daily for 2 days and every 12 hours thereafter. On Days 16 to 32, subjects also received either sertraline or placebo daily. The dose of sertraline was increased from 50 to 200 mg daily over 7 days; the 200-mg dose was given for 10 days. Samples for pharmacokinetic analyses were obtained on Days 15 and 32; trough plasma concentrations of carbamazepine and its principal metabolite, carbamazepine-10, 11-epoxide (CBZ-E), were determined daily beginning on Day 13. Cognitive function testing was performed on Day 1 before carbamazepine dosing (baseline), Day 15 (carbamazepine alone), and Day 32 (carbamazepine plus sertraline or placebo).

RESULTS

There were no significant differences between the sertraline and placebo groups in any of the pharmacokinetic parameters for carbamazepine or CBZ-E. Carbamazepine alone impaired cognitive function. The addition of sertraline did not potentiate these effects. Side effects were reported by 2 subjects in each group, but none were severe.

CONCLUSION

These findings indicate that sertraline does not affect the pharmacokinetics of carbamazepine or its principal metabolite and does not potentiate the cognitive effects of carbamazepine.

Molecular biology and cytogenetics of non-Hodgkin's lymphoma in children

Molecular analysis, combined with cytogenetic studies of proto-oncogenes and tumor suppressor genes, has provided insight into the pathogenesis of non-Hodgkin's lymphoma. Characterization of these malignancies at the molecular level will aid in developing more sensitive detection methods for earlier and more accurate diagnosis. Thus, genetic rearrangements provide highly specific molecular markers for monitoring malignant cells. Additionally, a more detailed understanding of the precise, molecular steps leading to malignant transformation will facilitate the development of more specific and, perhaps, less toxic therapies.

Accuracy and precision of joint space width measurements in standard and macroradiographs of osteoarthritic knees

OBJECTIVES

To improve the reproducibility and accuracy of joint space width (JSW) measurement as an assessment of cartilage loss in patients with osteoarthritis (OA) of the knee by determining how precision and accuracy of JSW measurement were altered by a computerised method of measurement, correction for radiographic magnification, radiography of the knee in the standing semiflexed view, and high definition macroradiography of the knee in the semiflexed view--taking JSW measurements from standard radiographs of OA knees in the extended view as the standard for comparison.

METHODS

Twenty five OA and 10 nonarthritic knees were radiographed in the extended view and minimum JSW was measured manually. Conventional and x5 macroradiographs were taken in the semiflexed view. All radiographs were taken twice on the same day and repeated two weeks later. Automated computerised measurement of minimum JSW was obtained from digitally stored images of all radiographs.

RESULTS

For medial compartment JSW measurements, computerised was more accurate than manual, correction for radiographic magnification improved precision and accuracy, measurements in the semiflexed view were more precise and accurate, and macroradiography increased measurement precision. For the lateral compartment JSW measurements, correction for radiographic magnification improved precision and accuracy, and the semiflexed view improved precision only.

CONCLUSIONS

Protocols defining radiographic and mensural procedures are essential for quality control of knee radiography in the semiflexed view to permit accurate and reproducible measurement of JSW. Macroradiography provides greater precision of JSW measurement.

Direct evaluation of electronic coupling mediated by hydrogen bonds: implications for biological electron transfer

Three supramolecular bischromophoric systems featuring zinc(II) and iron(III) porphyrins have been synthesized to evaluate the relative magnitudes of electronic coupling provided by hydrogen, sigma, and pi bonds. Laser flash excitation generates the highly reducing singlet excited state of the (porphinato)zinc chromophore that can subsequently be electron transfer quenched by the (porphinato)iron(III) chloride moiety. Measurement of the photoinduced electron transfer rate constants enables a direct comparison of how well these three types of chemical interactions facilitate electron tunneling. In contrast to generally accepted theory, electronic coupling modulated by a hydrogen-bond interface is greater than that provided by an analogous interface composed entirely of carbon-carbon sigma bonds. These results bear considerably on the analysis of through-protein electron transfer rate data as well as on the power of theory to predict the path traversed by the tunneling electron in a biological matrix; moreover, they underscore the cardinal role played by hydrogen bonds in biological electron transfer processes.

The dental health of single male hostel dwellers in Leeds

Attitudes and behaviour towards oral health among 104 homeless men in Leeds were assessed at interview. Of these, 101 agreed to a subsequent dental examination. The findings confirmed a high level of normative need despite a low level of felt need. Appointments were offered at two local community dental clinics, but the majority of men failed to attend. Appropriate provision of dental care is discussed and recommendations made for future developments.

Using Oncology Nursing Society Cancer Chemotherapy Guidelines as a basis for continuing education in rural hospitals

PURPOSE/OBJECTIVES

To describe a workshop developed to teach nurses caring for patients with cancer in a southern, rural area how to administer chemotherapy in an inpatient or homecare setting.

DATA SOURCES

The Oncology Nursing Society (ONS) Cancer Chemotherapy Guidelines and published articles and books.

DATA SYNTHESIS

An oncology clinical nurse specialist teaching at a local university developed and presented 10 hours of didactic content and a 6-hour clinical practicum. The workshop was conducted in association with a community hospital, which offered oncology care to patients with cancer in the community.

CONCLUSIONS

All nurses who successfully completed the workshop demonstrated improved ability in caring for patients with cancer and in administering chemotherapy. The ONS Cancer Chemotherapy Guidelines provided an excellent outline for the development of an initial course on the science of chemotherapy and management of related symptoms.

IMPLICATIONS FOR NURSING PRACTICE

Many nurses work in rural areas where they are expected to provide competent nursing care to a variety of specialized patient populations, yet they have limited access to educational opportunities. A workshop format is feasible and can provide the education necessary for nurses who care for patients with cancer.

Breast feeding, bottle feeding and dental caries in Kuwait, a country with low-fluoride levels in the water supply

A study was carried out in Kuwait, a country with low levels of fluoride in the water supplies, to determine the prevalence and extent of caries in early childhood, and enquire into associated factors. Mothers of pre-schoolchildren were interviewed, and their children aged 18 to 48 months received a dental examination. Of the 227 children examined, 107 (47 per cent) were caries free, and 41 (18%) had five or more dmf teeth. 'Nursing caries', affecting at least two maxillary incisors, was seen in 19 per cent of the sample. Breast fed children were significantly more likely to be caries free than those who were bottle fed from birth, although 'nursing caries' was positively associated with the practice of breast feeding at night 'at will' after 6 months of age (P < 0.01). Bottle fed children were more likely to develop caries, including 'nursing caries', particularly when the practice was continued to an older age. It was concluded that 'nursing caries' constitutes a significant dental health problem in Kuwait.

Dentists' perceptions of difficulties encountered in providing dental care for British Asians

British Asians represent a substantial proportion of the population in some parts of the United Kingdom, yet many fail to use dental services regularly. This study aimed to investigate dentists' concerns about providing care for this client group. Following a pilot study, a postal questionnaire was sent to general dental practitioners and community dental officers working in seven family health services authority localities. Of 1546 questionnaires circulated, 639 (41 per cent) were returned. The language barrier was most frequently identified as a major impediment to care (78 per cent), followed by patients' understanding of treatment proposed (67 per cent), while 64 per cent found difficulty obtaining medical histories. Only 20 per cent considered that gaining consent for treatment was a problem. Other issues concerned attendance as casual patients (65 per cent) and, in terms of treatment provided, difficulties with preventive (77 per cent), periodontal (66 per cent) and orthodontic care (27 per cent). The proportion of dentists identifying barriers to care reflected the English-speaking abilities of different Asian populations. Compared with the high percentage mentioning language, understanding and medical history, the small proportion of dentists who thought that consent was of concern suggests that concepts of consent may need to be questioned. Despite the low response rate, the high proportion of respondents identifying these issues implies that the present position may put patients' health at risk, restrict treatment options and offer a potential for litigation. Future initiatives to overcome barriers to appropriate care must address the perspectives of dentists treating British Asians, as well as that of the client group.

Structure-activity relationship of the effect of cis-unsaturated fatty acids on heart sarcolemmal phospholipase D activity

This study examined the role of fatty acids on the phosphatidylcholine-specific phospholipase D (PLD) function of purified sarcolemmal (SL) membranes isolated from rat hearts. The enzyme's hydrolytic activity was determined by measuring [14C] phosphatidic acid formation from exogenous [14C] phosphatidylcholine (PtdCho) in the absence or presence of the sodium salts of various saturated or unsaturated long-chain fatty acids (FA). In certain experiments the enzyme was also assayed in the transphosphatidylation mode. Cis-unsaturation and free carboxyl groups were structural prerequisites for the stimulatory effect exerted by FA on SL PLD. The most effective compounds were arachidonate and oleate, which maximally activated PLD at 4 and 5 mM concentration, respectively. To verify if a detergent-like mechanism was involved in PLD activation, anionic, zwitterionic and non-ionic detergents were used. Only anionic taurodeoxycholate had a slight effect, which was about 7% of that achieved by arachidonate or oleate. These results suggest that cis-unsaturated FA activate cardiac sarcolemmal PLD by a mechanism(s) which seems to be unrelated to non-specific perturbation of the membrane.

A study of factors governing fluid filtration in the diabetic foot

The effect of lowering the foot on the factors governing fluid filtration in the foot were studied in 12 male insulin-dependent diabetic subjects and 10 controls. Toe skin blood flow, measured by laser Doppler flowmetry, was significantly higher during dependency in the diabetic group. In the control subjects, the colloid osmotic pressure of venous blood sampled from the foot rose to 47.7 mmHg (range 45.1-53.8) after 50 min of foot dependency. In the diabetic group, colloid osmotic pressure failed to rise to the same extent (median 36.7 mmHg; range 28.6-43.0; P < 0.001). Capillary pressure, measured directly by the Landis microinjection technique, was significantly higher in the diabetic group (85.3 +/- 1.7 (n = 6) vs. 92.2 +/- 4.6 cm H2O (n = 6); P < 0.007), as was foot swelling rate determined by mercury strain gauge plethysmography (0.069 +/- 0.022 vs. 0.099 +/- 0.025 ml min-1 100 ml-1; P < 0.02). These results suggest an impairment of the oedema-preventing mechanisms in diabetic subjects which may contribute to the risks of ulceration in the diabetic foot.

A polymerase chain reaction assay for the detection of Brugia malayi in blood

There is need for sensitive, rapid, species-specific diagnosis of Brugia filarial parasites because traditional methods are tedious and time-consuming, with little guarantee of species specificity. A polymerase chain reaction (PCR)-based assay was developed using the Hha I family of highly repeated DNA sequences from Brugia. The assay was tested on 124 human blood samples collected in a field study in Indonesia. These included 66 microfilaria-positive samples from patients in an area endemic for Brugia, 30 from healthy individuals from the same endemic area, and 28 from healthy individuals from a nonendemic area. Twenty-eight blood samples collected in a village in French Polynesia endemic for Wuchereria bancrofti, but not B. malayi, were also tested. The blood samples were screened using the traditional blood smear and membrane filtration methods, which served as the gold standards to which the PCR assay was compared. The samples were digested with proteinase K, extracted with phenol and chloroform, and dialyzed. A fraction of the dialyzed product was used in PCRs using Hha I-specific primers. The PCR assay correctly identified all of the microfilaria-positive samples as PCR positive and all of the nonendemic samples as PCR negative. Additionally, 26 of 30 samples from healthy individuals in the endemic area were also identified as PCR negative, while four were PCR positive. It is likely that these four individuals had very low-level or cryptic infections, and that the PCR assay detected circulating DNA released from dead filariae. The results indicate that the Hha I PCR detection system is rapid, species-specific, and sensitive.

Molecular phylogenetic studies on Brugia filariae using Hha I repeat sequences

This paper is the first molecular phylogenetic study on Brugia parasites (family Onchocercidae) which includes 6 of the 10 species of this genus: B. beaveri Ash et Little, 1964; B. buckleyi Dissanaike et Paramananthan, 1961: B. malayi (Brug, 1927) Buckley, 1960; B. pahangi (Buckley et Edeson, 1956) Buckley, 1960; B. patei (Buckley, Nelson er Heisch, 1958) Buckley, 1960 and B. timori Partono et al., 1977. Hha l repeat sequences are 322 nucleotides long, highly repeated, tandemly arranged and unique to the nuclear genomes of the genus Brugia. Hha l repeat sequence data was collected by PCR, cloning and dideoxy sequencing. The Hha l repeat sequences were aligned and analyzed by maximum parsimony algorithms, distance methods and maximum likelihood methods to construct phylogenetic trees. Bootstrap analysis was used to test the robustness of the different phylogenetic reconstructions. The data indicated that the Hha l repeat sequences are highly conserved within species yet differ significantly between species. The various tree-building methods gave identical results. Bootstrap analyses on the Hha l repeat sequence data set identified at least two clades: the B. pahangi-B. beaveri clade and the B. malayi-B. timori-B. buckleyi clade; the first clade includes parasites of carnivores from Asia and America; the second includes species from primates and lagomorphs from Asiatic region. It was also noted that the Hha l repeat sequences obtained from B. malayi were identical to those obtained from B. timori, indicating very recent speciation.

NPR genes, which are negatively regulated by phytochrome action in Lemna gibba L. G-3, can also be positively regulated by abscisic acid

We have found that NPR1 and NPR2, two genes from Lemna gibba L. G-3 that can be negatively regulated by phytochrome action, can also be positively regulated by the plant hormone abscisic acid (ABA). Both genes were responsive to low concentrations of exogenous ABA; an increase in NPR1 RNA could be detected in response to concentrations as low as 10 nM. We have also tested phytochrome responsiveness of 5' promoter-deletion constructs of one of these genes, NPR1, in transient assays utilizing particle bombardment. This analysis demonstrated that DNA sequences important for phytochrome regulation are present downstream of -198 from the transcription start site. A response to ABA treatment could also be observed in the transient assay system. When intact plants were placed in darkness, there was an increase in ABA levels as well as increased levels of NPR1 and NPR2 RNA.