Chloroplast and nuclear DNA studies in a few members of the Brassica oleracea L. group using PCR-RFLP and ISSR-PCR markers: a population genetic analysis

A population genetic analysis of chloroplast and nuclear DNA was performed covering nine wild populations of Brassica oleracea. Three members of the n = 9 group, all close to B. oleracea, Brassica alboglabra Bailey, Brassica bourgeaui (Webb) O. Kuntze and Brassica montana Pourret, were also studied to better understand their relationship with B. oleracea. Chloroplast DNA was analysed using the PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism) method. The ISSR-PCR (inter-simple sequence repeat - polymerase chain reaction) technique was adopted to study nuclear DNA. Twelve primer pairs of chloroplast DNA showed very good amplification. The amplified product of each primer pair, digested by three restriction enzymes, revealed no variation of cpDNA among the taxa studied. This indicates they may have the same chloroplast genotype. Seven selected ISSR primers have detected genetic variation, both within and among the populations/taxa surveyed. The information obtained on the intra- and inter-populational genetic diversity of wild populations of B. oleracea neatly defined the individual plants. It could provide important guidelines for backing management and conservation strategies in this species. The study confirms a close relationship between B. alboglabra, B. bourgeaui and B. montana, which is parallel to their morphological similitude.

Relative efficacy of three medicinal plant extracts in the alteration of thyroid hormone concentrations in male mice

Relative importance of Bacopa monnieri (200 mg/kg), Aegle marmelos (1.00 g/kg) and Aloe vera (125 mg/kg) leaf extracts in the regulation of thyroid hormone concentrations in male mice was investigated. While serum levels of both T(3) and T(4) were inhibited by A. vera, A. marmelos extract could decrease only T(3) concentration. On the other hand, T(4) concentration was increased by B. monnieri extract suggesting its thyroid-stimulating role. When the relative potency of each plant extract was calculated in terms of percent increase or decrease in thyroid hormones, as compared to the control value, the decrease in T(3) concentration by A. marmelos was about 62% indicating its possible use in the regulation of hyperthyroidism. B. monnieri could increase T(4) concentration by 41% without enhancing hepatic lipid peroxidation (LPO) suggesting that it can be used as a thyroid-stimulating drug. In fact, hepatic LPO was decreased and superoxide dismutase (SOD) and catalase (CAT) activities were increased by B. monnieri and A. marmelos leaf extracts showing their antiperoxidative role. It is thus suggested that A. marmelos and A. vera may be used in the regulation of hyperthyroidism, while B. monnieri in hypothyroidism.

Drug use among the urban poor in Kolkata: behaviour and environment correlates of low HIV infection

BACKGROUND

HIV infection in injecting drug users (IDUs) has worked as a driving force for further spread of the virus in other population groups. Major metropolitan cities such as Mumbai, Kolkota, Chennai and Delhi have seen a diffusion of injecting drug use within the last decade. The prevalence of HIV infection among injectors ranges from 2% to 30%. Identifying effective interventional elements that have kept the prevalence of HIV low for the past 7 years among IDUs of Kolkata is thus of public health importance.

METHODS

A purposive sample of opioid/opiate users was studied. Primary and secondary data on drug users, law-enforcement environment, records at drug treatment centres, jail admission data related to the 'Narcotic Drug and Psychotropic Substance Act' and interventions in other risk groups were collected. Laboratory tests for HIV, hepatitis B surface antigen and syphilis were done on consenting IDUs (n=129) and non-IDUs (n=120). For univariate and multivariate analysis, IDUs were taken as cases and non-IDUs as controls.

RESULT

Of the IDUs, 2% were positive for HIV. No non-IDU was HIV-positive. Significantly more non-IDUs (10% v. 4%, p=0.05) were positive for syphilis. Sharing injection equipment within the past 6 months was reported by 71% of IDUs; sharing partners were stable and ranged from 1 to 3. More IDUs compared to non-IDUs reported being in touch with intervention programmes. The police has been tolerant to needle-syringe exchange and oral sublingual buprenorphine substitution conducted in Kolkata. Unlike in the early 1990s, non-IDUs did not switch to injecting during non-availability of brown sugar in the latter half of the 1990s and instead sought tratment. The availability of high quality heroin (>20%-50%) was low and the proportion of moderate quality heroin (>10%-20%) went up during these times due to increased police seizures. No intervention exists in jails despite the fact that a large number of drug users spend time in jail.

CONCLUSION

Stable and few injection equipment-sharing partners of IDUs, launching of early targeted interventions among IDUs and sex workers in the city, police tolerance to harm reduction activities and preference of non-IDUs for detoxification during heroin draught periods have kept HIV prevalence at a low level among drug users of Kolkata for the past 7 years. immediate launching of interventions for drug users in jails seems necessary. Similar multi-pronged strategies with targeted and environmental intervention could work in other settings as well.

Molecular bases of circadian rhythms

Circadian rhythms are found in most eukaryotes and some prokaryotes. The mechanism by which organisms maintain these roughly 24-h rhythms in the absence of environmental stimuli has long been a mystery and has recently been the subject of intense research. In the past few years, we have seen explosive progress in the understanding of the molecular basis of circadian rhythms in model systems ranging from cyanobacteria to mammals. This review attempts to outline these primarily genetic and biochemical findings and encompasses work done in cyanobacteria, Neurospora, higher plants, Drosophila, and rodents. Although actual clock components do not seem to be conserved between kingdoms, central clock mechanisms are conserved. Somewhat paradoxically, clock components that are conserved between species can be used in diverse ways. The different uses of common components may reflect the important role that the circadian clock plays in adaptation of species to particular environmental niches.

Interface between drug use and sex work in Manipur

BACKGROUND

In India, drug use is seen predominantly as a problem among men. This study attempts to address the interface between drug use and sex work among women drug users in Manipur and the prevalence of HIV, hepatitis B and other sexually transmitted infections in them.

METHODS

This cross-sectional survey was conducted between April and October 1997 at the time of an ethnic clash in imphal, the capital of Manipur. Sixty-nine women drug users were interviewed through street-based outreach workers; 38 women (55%) were injecting drug users. Data were generated with the help of a semi-structured questionnaire on sociodemography, drug use practice and health issues after obtaining informed consent from the participants. Subsequently, consent was also obtained from 60 respondents for collecting blood for unlinked anonymous tests for HIV and hepatitis B surface antigen. Clinical examination for reproductive tract infections, offered to all the study participants, generated data on sexually transmitted diseases.

RESULTS

The prevalence of HIV infection in injecting drug users was 57% (20/35) compared to 20% (5/25) among non-injecting drug users (p = 0.001), although the prevalence of hepatitis B surface antigen was similar in the two groups, 48% v. 56%, respectively. Eighty per cent of the respondents, many of whom migrated following the ethnic clash, reported having sex with non-regular partners, two-thirds reported sex in exchange for money or drugs. Eighty-one per cent (29/36) of women who agreed to have a clinical examination had abnormal vaginal discharge, of which 10 had endocervical discharge. The presence of infection was confirmed in only 24% of those with vaginal discharge--4 had bacterial vaginosis and 3 trichomoniasis.

CONCLUSION

Environmental interventions to reduce civil unrest and forced migration have an important role to play in HIV containment. The high rate of HIV infection, and the probability of a high rate of sexually transmitted infections in women drug users suggests that a targeted intervention in this population group is a public health need. An innovative outreach strategy should be designed for effective implementation of interventions among women injecting drug users and non-injecting drug users who operate from the streets as sex workers to support their drug habit as well as livelihood.

ELF3 modulates resetting of the circadian clock in Arabidopsis

The Arabidopsis early flowering 3 (elf3) mutation causes arrhythmic circadian output in continuous light, but there is some evidence of clock function in darkness. Here, we show conclusively that normal circadian function occurs with no alteration of period length in elf3 mutants in dark conditions and that the light-dependent arrhythmia observed in elf3 mutants is pleiotropic on multiple outputs normally expressed at different times of day. Plants overexpressing ELF3 have an increased period length in both constant blue and red light; furthermore, etiolated ELF3-overexpressing seedlings exhibit a decreased acute CAB2 response after a red light pulse, whereas the null mutant is hypersensitive to acute induction. This finding suggests that ELF3 negatively regulates light input to both the clock and its outputs. To determine whether ELF3's action is phase dependent, we examined clock resetting by using light pulses and constructed phase response curves. Absence of ELF3 activity causes a significant alteration of the phase response curve during the subjective night, and constitutive overexpression of ELF3 results in decreased sensitivity to the resetting stimulus, suggesting that ELF3 antagonizes light input to the clock during the night. The phase of ELF3 function correlates with its peak expression levels in the subjective night. ELF3 action, therefore, represents a mechanism by which the oscillator modulates light resetting.

Inhibition of T3 production in levothyroxine-treated female mice by the root extract of Convolvulus pluricaulis

An investigation was made to evaluate the role of Convolvulus pluricaulis root extract in the regulation of hyperthyroidism in female mice. Its possible site of action was also studied. L-Thyroxine treatment for 30 days increased serum concentrations of thyroxine (T4) and triodothyronine (T3). The activity of hepatic 5'-monodeiodinase (5'-DI) and glucose-6-phosphatase (G-6-Pase) was also enhanced. On the other hand, administration of the plant extract either alone or with L-T4, decreased serum T3 concentration and the activity of hepatic 5'-DI and G-6-phase, without marked alteration in hepatic lipid peroxidation, indicating the possible regulation of hyperthyroidism by the plant extract. It appears that the action of the plant extract on thyroid function is primarily mediated through the inhibition of 5'-DI enzyme activity.

Functional interaction of phytochrome B and cryptochrome 2

Light is a crucial environmental signal that controls many photomorphogenic and circadian responses in plants. Perception and transduction of light is achieved by at least two principal groups of photoreceptors, phytochromes and cryptochromes. Phytochromes are red/far-red light-absorbing receptors encoded by a gene family of five members (phyA to phyE) in Arabidopsis. Cryptochrome 1 (cry1), cryptochrome 2 (cry2) and phototropin are the blue/ultraviolet-A light receptors that have been characterized in Arabidopsis. Previous studies showed that modulation of many physiological responses in plants is achieved by genetic interactions between different photoreceptors; however, little is known about the nature of these interactions and their roles in the signal transduction pathway. Here we show the genetic interaction that occurs between the Arabidopsis photoreceptors phyB and cry2 in the control of flowering time, hypocotyl elongation and circadian period by the clock. PhyB interacts directly with cry2 as observed in co-immunoprecipitation experiments with transgenic Arabidopsis plants overexpressing cry2. Using fluorescent resonance energy transfer microscopy, we show that phyB and cry2 interact in nuclear speckles that are formed in a light-dependent fashion.

Distribution of HIV-1 subtypes in female sex workers of Calcutta, India

BACKGROUND & OBJECTIVES

Different routes for the transmission of HIV-1 in India have been reported and the majority of infections occurred through heterosexual route of transmission. In order to understand the dynamics of HIV-1 transmission, a systematic study was undertaken to determine the viral subtypes circulating among the female sex workers in Calcutta, India.

METHODS

Peptide enzyme immunoassay (PEIA), heteroduplex mobility assay (HMA) and DNA sequence analysis were used to ascertain the HIV-1 subtypes.

RESULTS

V3 serotyping of 52 HIV-1 seropositive samples identified 33 (60%) to be subtype C. A DNA fragment within C2-V3/C2-V5 regions of HIV-1 gp120 was amplified directly from the lymphocyte DNA to avoid any bias in selecting viral variants and used in HMA. Of the 40 samples analyzed, 38 (95%) belonged to subtype C and 2 were found to be non-typable. Further analysis of these 38 samples revealed that 26 (68%) had maximum homology to the C3-Indian reference strain (IND868), 11 (29%) were most homologous to C2-Zambian strain (ZM18) and 1 (3%) showed close resemblance to C1-Malawi strain (MA959). Nucleotide sequence of 11 subsamples encompassing about 325 base pairs was aligned for the Indian and other geographically distinct isolates. On distance and parsimony trees, most of the samples (8/11) clustered together as subtype C.

INTERPRETATION & CONCLUSIONS

Subtype C was the major circulating HIV-1 strain in this geographical region, although variation within this subtype was also noticed. DNA sequence analysis was found to be the best method in determining the nature of the HIV-1 subtype followed by HMA and peptide enzyme immunoassay. These findings may have important implications for the design of effective vaccines in India and emphasizes the need for constant monitoring of the HIV-1 subtypes in different parts of India.

Cloning of the Arabidopsis clock gene TOC1, an autoregulatory response regulator homolog

The toc1 mutation causes shortened circadian rhythms in light-grown Arabidopsis plants. Here, we report the same toc1 effect in the absence of light input to the clock. We also show that TOC1 controls photoperiodic flowering response through clock function. The TOC1 gene was isolated and found to encode a nuclear protein containing an atypical response regulator receiver domain and two motifs that suggest a role in transcriptional regulation: a basic motif conserved within the CONSTANS family of transcription factors and an acidic domain. TOC1 is itself circadianly regulated and participates in a feedback loop to control its own expression.

Transmission of HIV from injecting drug users to their wives in India

We aimed to identify factors associated with transmission of human immunodeficiency virus (HIV) from injecting drug users (IDUs) to their wives in Manipur, northeast India, where the prevalence of HIV among IDUs is 80% via a case-control study. One hundred and sixty-one HIV-infected IDUs and their wives were recruited from September 1996 to August 1997 inclusive. HIV status was determined by enzyme-linked immunosorbent assay (ELISA) plus Western blot, Interviews were administered anonymously. Regression analysis identified factors associated with transmission of HIV from IDU husbands to their non-injecting wives. Seventy-two wives (45%) were HIV-positive. Only 15% of the couples reported regular usage of condoms during intercourse. On multivariate analysis, a sexually transmitted disease (STD) in either member, reported by the husband, estimated duration of HIV in the husband for >8 years, and a history of blood transfusions were associated with infection in the wife. In conclusion, STDs are associated with transmission of HIV from husband to wife. Improved control of STDs, condom promotion, and improved blood screening are urgently needed in Manipur.

Withania somnifera root extract in the regulation of lead-induced oxidative damage in male mouse

The importance of Withania somnifera root extract in the regulation of lead toxicity with special reference to lipid peroxidative process has been investigated in liver and kidney tissues. While lead treatment (0.5 mg kg(-1)body wt. day(-1)for 20 days) enhanced hepatic and renal lipid peroxidation (LPO), administration of plant extract in the doses of 0.7 g kg(-1)and 1.4 g kg(-1)body wt. day(-1)along with equivalent doses of lead acetate for 20 days significantly decreased LPO and increased the activities of antioxidant enzymes, viz., superoxide dismutase (SOD) and catalase (CAT), thus retaining normal peroxidative status of the tissues. We suggest that the ameliorating role of root extract of W. somnifera in the lead intoxicated mice could be the result of its antiperoxidative action.

HIV-1 subtypes in injecting drug users & their non-injecting wives in Manipur, India

The presence of HIV-1 antibodies was determined among the injecting drug users (IDUs) and their non-injecting wives. A total of 233 (72%) were found to be HIV-1 seropositive among the 322 subjects recruited in this study between August, 1996 and September, 1997. The distribution of HIV-1 subtypes among the injecting drug users (IDUs) and their wives was determined using peptide enzyme immunoassay (EIA). Sexual transmission of HIV-1 occurred frequently (45%) from HIV-1 infected IDUs to their spouses. The majority of the subjects (167/233) were infected with subtype C followed by subtype Thai B (29/233). Subtype C was the most common among both IDUs (78%) and their wives (57%), followed by subtype Thai B (12% and 13% respectively). The distribution of subtypes was significantly different between IDUs and their wives with a lower percentage of subtype C and higher percentage of subtype D in the infected wives (P < 0.03). Discordance for subtypes transmitted from IDUs to their wives suggests the occurrence of dual and/or recombinant infection in the IDUs.

Discrete breathers: exact solutions in piecewise linear models

Exact breather solutions are constructed in piecewise linear (PWL) versions of the discrete nonlinear Schrodinger and Klein-Gordon equations. These solutions correspond to intersections of stable and unstable manifolds of relevant fixed points in associated 2D mappings, an exact construction of which is possible due to the PWL nature of the models. Such exact solutions give us insight into several aspects of breather properties. The problem of dynamical stability of the breathers is mentioned as an instance, detailed results on which will be presented in a future paper.

How safe is neem extract with respect to thyroid function in male mice?

In this investigation we attempted to find out the hitherto unstudied adverse effects of neem (Azardirachta indica) leaf extract on the thyroid function of male mice. Neem leaf extract was orally administered in two different doses (40 mg and 100 mg kg(-1)day(-1)for 20 days). The extract exhibited differential effects. While the higher dose decreased serum tri-iodothyonine (T(3)) and increased serum thyroxine (T(4)) concentrations, no significant alterations of levels were observed in the lower dose group, indicating that the high concentrations of neem extract can be inhibitory to thyroid function, particularly in the conversion of T(4)to T(3), the major source of T(3)generation. A concomitant increase in hepatic lipid peroxidation (LPO) and a decrease in glucose-6-phosphatase (G-6-Pase) activity in the higher dosed group also indicated the adverse effect of neem extract despite an enhancement in the activities of two defensive enzymes, superoxide dismutase (SOD) and catalase (CAT). Thus, it appears that the higher concentration of neem extract may not be safe with respect to thyroid function and lipid peroxidation.

Prevalence of HCV & HBV infection amongst HIV seropositive intravenous drug users & their non-injecting wives in Manipur, India

Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections were evaluated among 77 Manipuri couples of whom all husbands were both intravenous drug users (IDUs) and human immunodeficiency virus (HIV) positive. This study showed for the first time a high prevalence of HCV (92%) and HBV (100%) infection amongst the IDUs in Manipur. Stringent control measures to prevent the transmission of hepatitis viruses (B and C) are urgently required in Manipur.

Hepatitis E virus in Cuba

The hepatitis E virus (HEV) has a global distribution and is known to have caused large waterborne epidemics of icteric hepatitis. The transmission is primarily fecal-oral. Some reports have suggested parenteral transmission of HEV from its association to hepatitis B or hepatitis C infection, or due to the development of hepatitis E after blood transfusion. Though most of the developing countries in Asia and Africa have been shown to be endemic for HEV infection, studies in the Latin American countries have been limited to Mexico, Brazil and Venezuela. We have developed an enzyme immunoassay (EIA) for IgM and IgG antibodies to a recombinant protein containing antigenic epitopes of the ORF3 region of the HEV. This system, as well as a commercial kit that includes ORF2 and ORF3 antigenic epitopes, were used to study the prevalence of anti-HEV antibodies in a sample of Cuban blood donors, acute hepatitis cases and individuals subjected to plasmapheresis. The incidence of anti-HEV IgM was compared with other viral hepatitis markers. Our findings suggest that infections due to HEV are an important viral cause of sporadic hepatitis in Cuba, and that HEV is endemic to this region of the world.

Withania somnifera and Bauhinia purpurea in the regulation of circulating thyroid hormone concentrations in female mice

The effects of daily administration of Withania somnifera root extract (1.4 g/kg body wt.) and Bauhinia purpurea bark extract (2.5 mg/kg body wt.) for 20 days on thyroid function in female mice were investigated. While serum triiodothyronine (T3) and thyroxine (T4) concentrations were increased significantly by Bauhinia, Withania could enhance only serum T4 concentration. Both the plant extracts showed an increase in hepatic glucose-6-phosphatase (G-6-Pase) activity and antiperoxidative effects as indicated either by a decrease in hepatic lipid peroxidation (LPO) and/or by an increase in the activity of antioxidant enzyme(s). It appears that these plant extracts are capable of stimulating thyroid function in female mice.

Inhibition of triiodothyronine production by fenugreek seed extract in mice and rats

The effects of fenugreek seed extract on the alterations in serum thyroid hormone concentrations were studied in adult male mice and rats. Simultaneously, hepatic lipid peroxidation (LPO) and the activities of the antioxidant enzymes, viz superoxide dismutase (SOD) and catalase (CAT) were examined. Administration of methi seed extract (0.11 g kg body wt.(-1) day(-1) for 15 days) to both mice and rats significantly decreases serum triiodothyronine (T(3)) concentration and T(3)/T(4) ratio, but increases thyroxine (T(4)) levels and body weight. While hepatic LPO and CAT activities were not altered, a significant decrease in SOD activity was observed in both the animal models. These findings suggest that fenugreek seed extract induced inhibition in T(4)to T(3) conversion is not peroxidation-mediated and the inhibition in SOD activity could be the result of a decrease in the protein anabolic hormone, T3.

Gugulu (Commiphora mukul) induces triiodothyronine production: possible involvement of lipid peroxidation

An investigation was made to find out the importance of gugulu (Commiphora mukul) in thyroid function of mice and to reveal the possible involvement of lipid peroxidation (LPO), if any. While no marked change in the concentrations of serum thyroxine (T4) was observed, triiodoth yronine (T3) concentration and T3/T4 ratio were enhanced following the administration of gugulu extract (0.2 g/kg b. wt./d for 15 days). A concomitant decrease in LPO was also noticed in liver, the principal site of T3 generation, suggesting that gugulu induced increase in T3 concentration is LPO mediated.