The use of ultrasound-based 'soft markers' for the prediction of pelvic pathology in women with chronic pelvic pain-can we reduce the need for laparoscopy?

OBJECTIVE

To assess the accuracy of new transvaginal ultrasound-scan-based markers and to compare them to conventional ultrasound methods used in the detection of common pelvic pathology in women with chronic pelvic pain (CPP).

DESIGN

A prospective observational study.

SETTING

Teaching hospital.

POPULATION

A total of 120 consecutive women with CPP undergoing transvaginal ultrasonography before either diagnostic or operative laparoscopy.

METHODS

Anatomical abnormalities, e.g. endometrioma or hydrosalpinx (hard markers), were documented. The woman was then assessed for the presence or absence of 'soft markers' (reduced ovarian mobility and site-specific pelvic tenderness).

MAIN OUTCOME MEASURE

Presence or absence of pelvic pathology noted during laparoscopy.

RESULTS

Seventy women had pelvic pathology, of whom 51 had endometriosis alone, 7 both endometriosis and pelvic adhesions, 6 pelvic adhesions, 1 hydrosalpinx with endometriosis and 5 hydrosalpinx and pelvic adhesions. The likelihood ratio for the hard markers was infinity (specificity was 100%), for the soft makers 1.9 (95% CI 1.2-3.1) and for a 'normal' ultrasound 0.18 (0.09-0.34). The pre-test probability of pelvic disease in our population of women with CPP was 58%, and this probability of disease was raised to 100% with the presence of hard markers and to 73% with the presence of soft markers. The pre-test probability of 58% fell to 20% when ultrasound finding was found to be normal.

CONCLUSION

This new approach improves the detection and exclusion of significant pathology in women with CPP and may lead to a reduction in the number of unnecessary laparoscopies carried out on women with CPP.

[Effect of substrate-dependent microbialy produced ethylene on plant growth]

Various compounds have been identified as precursors/substrates for the synthesis of ethylene (C2H4) in soil. This study was designed to compare the efficiency of four substrates, namely L-methionine (L-MET), 2-keto-4-methylthiobutyric acid (KMBA), 1-aminocyclopropane-1-carboxylic acid (ACC), and calcium carbide (CaC2) for ethylene biosynthesis in a sandy clay loam soil by gas chromatography. The classic "triple" response in etiolated pea seedling was employed as a bioassay to demonstrate the effect of substrate-dependent microbialy produced ethylene on plant growth. Results revealed that an amendment with L-MET, KMBA, ACC (up to 0.10 g/kg soil) and CaC2 (0.20 g/kg soil) significantly stimulated ethylene biosynthesis in soil. Overall, ACC proved to be the most effective substrate for ethylene production (1434 nmol/kg soil), followed by KMBA, L-MET, and CaC2 in descending order. Results further revealed that ethylene accumulation in soil released from these substrates created a classic "triple" response in etiolated pea seedlings with different degrees of efficacy. A more obvious classic "triple" response was observed at 0.15, 0.10, and 0.20 g/kg soil of L-MET, KMBA/ACC, and CaC2, respectively. Similarly, direct exposure of etiolated pea seedlings to commercial ethylene gas also modified the growth pattern in the same way. A significant direct correlation (r = 0.86 to 0.97) between substrate-derived [C2H4] and the classic triple response in etiolated pea seedlings was observed. This study demonstrated that the presence of substrate(s) in soil may lead to increased ethylene concentration in the air of the soil, which may affect plant growth in a desired direction.

Structural basis of acetylcholinesterase inhibition by triterpenoidal alkaloids

Acetylcholinesterase plays a crucial role in the metabolism of neurotransmitter, acetylcholine. Inhibition of Torpedo californica acetylcholinesterase by triterpenoidal alkaloids buxamine-B (1) and buxamine-C (2) has been studied by enzyme kinetics and molecular docking experiments. Buxamine-C (2) has been found to be 20-fold potent than buxamine-B (1) (Ki = 5.5 and 110 microM, respectively). The ligand docking experiments predicted that the cyclopentanophenanthrene skeleton of both inhibitors properly fits into the aromatic gorge of the enzyme. The C-3 and C-20 amino groups of both alkaloids mimic the well-known bis-quaternary ammonium inhibitors such as decamethonium and interact with Trp84 and Trp279 residues of the enzyme, respectively. The C-3 amino group in buxamine-C (2) appears to be better positioned at the bottom of the aromatic gorge and thus seems to be crucial for the inhibitory activity of such inhibitors.

Juliflorine: A potent natural peripheral anionic-site-binding inhibitor of acetylcholinesterase with calcium-channel blocking potential, a leading candidate for Alzheimer’s disease therapy

The alkaloid juliflorine (1) from Prosopis juliflora inhibited acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BChE, EC 3.1.1.8) enzymes in a concentration-dependent fashion with IC50 values 0.42 and 0.12 microM, respectively. Lineweaver-Burk as well as Dixon plots and their secondary replots indicated that the nature of inhibition was purely of non-competitive type with Ki values 0.4 and 0.1 microM, against AChE and BChE, respectively. By molecular docking studies compound 1 was found to be ideally spaced inside the aromatic gorge of AChE with rings A/B remaining at the top and rings C/D penetrating deep into the gorge, that might be due to the greater hydrophobicity of rings C/D as compared to rings A/B, allowing their simultaneous interaction with the peripheral anionic and quaternary ammonium-binding sites. The 1-AChE complex was found to be stabilized by hydrophobic contacts, hydrogen bonding, and pi-pi stacking between the compound 1 and amino acid residues of the aromatic gorge of AChE. Amino acid residues Tyr70, Asp72, Tyr121, Trp279, and Tyr334 of the peripheral anionic site (PAS) of AChE were found to be exclusively involved in the hydrophobic contacts with compound 1 that might be responsible for the competitive mode of inhibition. Compound 1 also showed dose-dependent (30-500 microg/mL) spasmolytic and Ca2+-channel blocking activities in isolated rabbit jejunum preparations. The cholinesterase inhibitory potential along with calcium-channel blocking activity of compound 1 and safe profile in human neutrophils viable assay could make it a possible drug candidate for Alzheimer's disease.

Do we need to follow up complete miscarriages with serum human chorionic gonadotrophin levels?

Despite a history of heavy vaginal bleeding with clots, a proportion of women diagnosed with complete miscarriage, using transvaginal sonography (TVS), have an underlying ectopic pregnancy (EP). We evaluated the need for hormonal follow up in women with history and scan findings suggestive of complete miscarriage. One hundred and fifty-two consecutive women with findings suggesting complete miscarriage at presentation based on their history and TVS were presented to the Early Pregnancy Unit. Serum human chorionic gonadotrophin (hCG) levels were taken at presentation and 48 hours. All women were followed up until hCG was <5 u/L or a pregnancy was visualised on TVS either inside or outside the uterus. Overall, 9 (5.9%) of 152 women with an apparent complete miscarriage had an underlying EP. A diagnosis of complete miscarriage based on history and scan findings alone is unreliable. These women should be managed as 'pregnancies of unknown location' with serum hCG follow up.

A prospective evaluation of a single-visit strategy to manage pregnancies of unknown location

BACKGROUND

The aim was to assess whether women with a pregnancy of unknown location (PUL) can be safely excluded from potentially unnecessary multiple clinic visits.

METHODS

A single-visit protocol was developed based upon data from 200 consecutive PULs. PULs were divided into groups according to the probable risk of ectopic pregnancy. Those PULs with an initial serum progesterone < or =10 nmol/l or a serum HCG of < or =25 U/l were deemed to be at low risk and classified as resolving or failing PULs. Those PULs with an initial serum progesterone of >50 nmol/l, regardless of serum HCG, were thought to be a probable intra-uterine pregnancy (IUP) and were also classified as being low risk. Those PULs with an initial serum progesterone of 10-50 nmol/l and a serum HCG of >25 U/l were classified as being at high risk. This protocol was then tested prospectively on 318 consecutive PULs. Management was based solely on the basis of an initial transvaginal ultrasound scan (TVS) and a single measurement of HCG and progesterone taken at the time of initial consultation.

RESULTS

A total of 5544 consecutive women were scanned, of which 560 (10.1%) women were classified as PULs. Forty-two were lost to follow-up and therefore 518 (9.34%) were analysed. In the training set of 200 PULs, there were 111 (55.5%) failing PULs, 67 (33.5%) IUPs and 22 (11%) ectopic pregnancies. In the test set of 318, there were 189 (59.4%) failing PULs, 114 (35.8%) IUPs and 15 (4.7%) ectopic pregnancies. For the training group, the sensitivity and specificity of a single visit to detect low-risk PULs were 77 and 82%, respectively. The positive (PPV) and negative predictive values (NPV) were 97 and 31%, respectively. For the test group of 318 PULs, the sensitivity and specificity were 84 and 33%, respectively. The PPV and NPV were 96 and 9.4%, respectively.

CONCLUSIONS

A single-visit strategy based on commonly used criteria eliminates 84% of non-ectopic pregnancies correctly from the system. However, as 67% of ectopic pregnancies are discharged without adequate follow-up, a single-visit strategy should not be used as an alternative to the current multi-visit strategy used in most units.

Presence of antispasmodic, antidiarrheal, antisecretory, calcium antagonist and acetylcholinesterase inhibitory steroidal alkaloids in Sarcococca saligna

The aim of this investigation was to see if the crude extract of Sarcococca saligna (Ss.Cr) contains chemicals with gut function inhibitory activity by using in vitro and in vivo assays. Ss.Cr caused a dose-dependent (0.03 - 3 mg/mL) inhibitory effect on K+-induced contractions in rat stomach fundus, guinea-pig ileum and rabbit jejunum preparations. The calcium channel blocking(CCB) activity was confirmed when Ss.Cr caused a rightward shift in the Ca++ dose-response curves. It also potentiated, at lower do-ses (0.001 - 0.03 mg/mL), the contractile effect of a fixed dose of acetylcholine (ACh), similar to physostigmine, and suppressed the effect of ACh at higher doses (0.3 - 1.0 mg/mL). Both Ss.Cr and physostigmine inhibited acetylcholinesterase (AChE), in the in vitro assay, confirming the AChE inhibitory activity. In the in vivo studies, Ss.Cr exhibited antidiarrheal and antisecretory activities against castor oil-induced diarrhea and intestinal fluid accumulation in mice. Characteristic steroidal compounds of the plant (saracocine, saracodine, saracorine and alkaloid-C), exhibited a similar combination of AChE inhibitory and CCB activities. Thus this study provides a sound mechanistic base for some of the traditional uses of the plant in hyperactive gut states, in addition to providing the first evidence for verapamil to possess additional AChE inhibitory activity. Furthermore, these characteristic compounds with dual activity may be good candidates for further studies on their usefulness in Alzheimer's disease.

In vitro assessment of anti - cutaneous leishmaniasis activity of some Sudanese plants

Examination of crude methanol extracts of four Sudanese plants (Azadirachta indica, Acacia nilotica, Balanites aegyptiaca and Allium sativa) revealed that only three species had a considerable in-vitro anti-leishmanial activity on Leishmania major promastigotes. The plants Azadrachta indica, Allium sativa, and Acacia nilotica gave a LC50 of 10.2, 4.94, and 89.38 microg/ml, respectively. Extracts of Balanites aegyptiaca had a moderate biological activity on L major promastigotes.

Cholinesterase inhibitory and spasmolytic potential of steroidal alkaloids

A new steroidal alkaloid, isosarcodine (1) along with four known bases, sarcorine (2), sarcodine (3), sarcocine (4) and alkaloid-C (5) were isolated from the MeOH extract of Sarcococca saligna. The structures of these alkaloids were identified by spectral data interpretation. These compounds were subjected to acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition studies, and were found to be noncompetitive inhibitors of AChE (Ki = 21.8, 90.3, 32.2, 16.0 and 50.0 microM, respectively) and uncompetitive or noncompetitive inhibitors of BChE (Ki = 8.3, 7.5, 15.6, 5.0 and 12.0 microM, respectively). The compounds (2-5) also showed dose-dependent spasmolytic activity in the rabbit jejunum intestinal preparations and also relaxed the high K+ (80 mM)-induced contraction, indicative of a calcium channel-blocking mechanism. Structure-activity relationship suggested that the nitrogen substituents at C-3 and/or C-20 of steroidal skeleton and the hydrophobic properties of the pregnane skeleton are the key structural features contributed to the inhibitory potency of these steroidal alkaloids against AChE and BChE.

Use of microsatellite marker loss of heterozygosity in accurate diagnosis of pancreaticobiliary malignancy from brush cytology samples

BACKGROUND

Brush cytology of biliary strictures to diagnose pancreaticobiliary malignancy suffers from poor sensitivity.

AIM

To improve the diagnostic yield of pancreaticobiliary brush cytology through analysis of tumour suppressor gene linked microsatellite marker loss of heterozygosity (LOH) and k-ras codon 12 mutation detection.

METHODS

Twenty six patients with biliary strictures underwent endoscopic retrograde cholangiography with brush cytology. A panel of 12 polymorphic microsatellite markers linked to six tumour suppressor genes was developed. Genomic DNA from cell clusters acquired from brush cytology specimens and microdissected surgical malignant and normal tissue underwent polymerase chain amplification reaction (PCR). PCR products were compared for LOH and k-ras codon 12 mutations.

RESULTS

Seventeen patients were confirmed to have pancreaticobiliary adenocarcinoma. Nine patients had benign strictures (eight proven surgically, one by follow up). Cytomorphological interpretation was positive for malignancy (n = 8), indeterminate (n = 10), and negative for malignancy (n = 8). Selected malignant appearing cytological cell clusters and microdissected histological samples from cancer showed abundant LOH characteristic of malignancy while brushings from nine cases without cancer carried no LOH (p<0.001). LOH and k-ras mutations profile of the cytological specimens was almost always concordant with the tissue samples. Presence of k-ras mutation predicted malignancy of pancreatic origin (p<0.001).

CONCLUSION

LOH and k-ras codon 12 mutation analysis of PCR amplified DNA from biliary brush cytology discriminates reactive from malignant cells, with 100% sensitivity, specificity, and accuracy. Minor variations in LOH in brushings and in different sites within the same tumour likely reflect intratumoral mutational heterogeneity during clonal expansion of pre- and neoplastic lineages.

Presence of cholinomimetic and acetylcholinesterase inhibitory constituents in betel nut

In this investigation, we report the presence of cholinomimetic and acetylcholinesterase (AChE) inhibitory constituents in betel nut, the most commonly used drug in the world after tobacco, ethanol and caffeine. The crude extract of betel nuts or Areca catechu (Ac.Cr) caused a dose-dependent (0.3-300 microg/mL) spasmogenic effect in the isolated rabbit jejunum. The spasmogenic effect was blocked by atropine, similar to that of acetylcholine (ACh), suggestive of muscarinic receptor mediated effect. Both the extract (0.3-10 microg/mL) and physostigmine (0.1-3.0 microM) potentiated the effect of a fixed dose of ACh (10 microM) in a dose-dependent fashion, suggesting acetylcholinesterase (AChE) inhibitory effect. This effect was confirmed in the in vitro assay where both the crude extract (1-100 microg/mL) and physostigmine inhibited the enzyme. In the in vivo model of gastrointestinal transit, Ac.Cr (10-30 mg/kg) enhanced the travel of charcoal meal and also exhibited a laxative effect in mice. The plant extract was subjected to activity-directed fractionation and all resultant fractions showed atropine-sensitive spasmogenicity in rabbit jejunum and also AChE inhibitory effect at doses similar to that for the parent crude extract, the ethyl acetate fraction being slightly less potent. Some of the known constituents of betel nut, including arecoline, were tested for the possible inhibitory effect on AChE, none were found active. The study provides first evidence for the presence of AChE inhibitory constituents in betel nut, though additional direct muscarinic stimulatory effect cannot be ruled out and this study provides sound scientific basis for some of the folkloric uses associated with betel nut chewing.

Kinetics and effects of trace elements and electron complexes on 2-keto-4-methylthiobutyric acid-dependent biosynthesis of ethylene in soil

AIMS

2-Keto-4-methylthiobutyric acid (KMBA) is an established intermediate in microbial biosynthesis of ethylene from methionine. This study demonstrates the kinetics and effects of trace elements and electron complexes on substrate (KMBA)-derived C2H4 biosynthesis in soil.

METHODS AND RESULTS

We have previously reported KMBA-dependent C2H4 production in soil. We studied the kinetics and effects of various trace elements and electron complexes on KMBA-derived C2H4 biosynthesis in soil by gas chromatography. Kinetic analysis revealed that ethylene forming enzyme (EFE) reaction was linear (R2 = 0.9448) when velocity of reaction (V) was plotted against substrate [S] over the range from 2.5 to 10 mmol l(-1) and thus followed a first order reaction. Application of three linear transformations of the Michaelis-Menten equation indicated high affinity of EFE for the substrate because Km values ranged between 5.4 and 6.67 mmol l(-1) and Vmax of reaction was between 22.4 and 35.7 nmol kg(-1) soil 120 cm(-1). Most of the trace elements exhibited positive effects on KMBA-dependent C2H4 production in soil. Maximum stimulatory effect on C2H4 biosynthesis was observed in response to Co(II) application, while Fe(III) inhibited the biotransformation of KMBA into C2H4. Contrarily, most of the tested electron complexes inhibited KMBA-derived C2H4 biosynthesis in the soil. However, lower concentrations (1.0 mmol l(-1)) of mannitol and hydroquinone were stimulatory to C2H4 production in soil compared with controls (substrate only).

CONCLUSIONS

The results revealed that both kind and concentration of trace elements and electron complexes affected the substrate-dependent production of C2H4 in soil with different degrees of efficacy.

SIGNIFICANCE AND IMPACT OF THE STUDY

The C2H4 in the root environment could be physiologically active even at low concentrations, so knowledge regarding various factors which regulate C2H4 biosynthesis in soil could be of significance for plant growth and development.

Should we be examining the ovaries in pregnancy? Prevalence and natural history of adnexal pathology detected at first-trimester sonography

OBJECTIVE

To assess the prevalence and natural history of ovarian pathology in pregnancy.

METHODS

Three thousand consecutive pregnant women presenting before 14 weeks' gestation at the early pregnancy unit at St George's Hospital, London, underwent ultrasound examination during which both ovaries were visualized. Women found to have a simple ovarian cyst with a minimum diameter > or =25 mm or a complex ovarian cyst of any size were included in the study. They were followed up with ultrasound scans every 4-6 weeks until either resolution of the ovarian cyst occurred, intervention was required or the pregnancy was concluded. If the cyst persisted at 20 weeks' gestation, these women were rescanned 6 weeks after conclusion of the pregnancy. Women were managed expectantly throughout their pregnancy.

RESULTS

One hundred and sixty one women with a total of 166 cysts were included for analysis. At presentation, 43.7% of the women were asymptomatic and 56.3% had pain and/or vaginal bleeding. The mean gestational age at presentation was 53 (range, 28-98) days, the mean maternal age was 30 (range, 17-42) years, and the mean ovarian cyst diameter was 48 (range, 12-115) mm. The first-trimester pregnancy diagnoses were 106 intrauterine pregnancies, 40 miscarriages, five ectopic pregnancies, three pregnancies of unknown location and seven terminations of pregnancy. The sonographic features of the ovarian cysts included: 117 simple and anechoic, 21 hemorrhagic, 16 with mixed echogenicity, seven with a ground-glass appearance, three solid/cystic with papillary projections and two with low-level echoes. One hundred and nineteen (71.7%) of the cysts resolved spontaneously and were presumed to be physiological, 40 (24.1%) persisted and seven (4.2%) required intervention, four of these as an emergency because of pain. There was one case of borderline malignancy and no cases of malignancy. Five (3.0%) of the cysts underwent torsion. Only 0.13% (4/3000) of all women who initially presented to our unit required acute intervention during their pregnancy.

CONCLUSIONS

The majority of cysts detected in early pregnancy are physiological and resolve. Very few persist and intervention during the pregnancy is rarely indicated. The expectant management of ovarian cysts detected in the first trimester is safe and should be encouraged. Examining the ovaries in the first trimester is of limited value.

The use of a new logistic regression model for predicting the outcome of pregnancies of unknown location

BACKGROUND

The aim of this study was to generate and evaluate new logistic regression models from simple demographic and hormonal data to predict the outcome of pregnancies of unknown location (PULs).

METHODS

Data were collected prospectively from 185 consecutive women classified as having a PUL by transvaginal scan; blood was taken at presentation and 48 h later to measure serum progesterone and HCG. These women were followed-up until the outcome was established: an intrauterine pregnancy (IUP), an ectopic pregnancy (EP) or a failing PUL. Three multi-categorical logistic regression models were tested. M1 was based on the HCG ratio (rate of change in HCG over 48 h), M2 was based on the average progesterone level (the mean of the progesterone level at 0 and 48 h) and M3 was based on the patient's age.

RESULTS

A total of 102 failing PULs, 63 IUPs and 20 EPs were used in the training set to develop the new models. The best of these models, M3, gave a retrospective area under the receiver operating characteristic (ROC) curve of 0.984 for failing PUL, 0.995 for IUP and 0.920 for EP. All three models were tested prospectively on the test set of 196 cases. M1 outperformed M2 and M3 when tested prospectively. The area under the ROC curve (AUC) was 0.975 for failing PUL, 0.966 for IUP and 0.885 for EP. M1, for the detection of EP, had a sensitivity of 91.7%, a specificity of 84.2%, a positive likelihood ratio of 5.8, a positive predictive value of 27.5% and a negative predictive value of 99.4%.

CONCLUSIONS

The logistic regression model M1, can predict which PULs will become failing PULs, IUPs and, most importantly, EPs based on the patient's HCG ratio alone.

Epidemiology and Etiology of Intractable Epilepsy in Qatar

The medical records of 219 epileptic patients seen over a period of eight years were reviewed to determine the incidence and causes of intractable epilepsy amongst adults in Qatar: The incidence rate of hospital admission with uncontrolled epilepsy was calculated as 25per 100,000persons. Thirty-nine patients (18%) fulfilled the criteria for IE and the incidence of IE could be approximated at 4.5 per 100,000 persons. In the native Qatari population the approximated incidence of IE would be 1 in 100,000 persons per year, while in the expatriate population the rate would be 3.5 per 100,000 persons per year. The most common type of IE was idiopathic generalized epilepsy (75%) followed by symptomatic epilepsy (19%) and temporal lobe epilepsy (6%). To calculate the crude incidence of epilepsy in Qatar, the records were reviewed of 1217patients (aged 13-85 years) visiting the outpatient department or admitted to hospital because of a newly diagnosed epilepsy during the calendar year, 1st January-31st December 2001. These figures were extrapolated to an approximation of an incidence of 174 in 100,000 persons per year.

The presence of dental fluorosis in the permanent dentition in Doha

The main purpose of this study is to draw attention to the presence and the severity of dental fluorosis in Doha [Qatar] through the high level of registered cases of fluorosis found among the groups examined. Of 4800 people aged 8-50 years, 2654 [55.29%] had dental fluorosis of some degree. This problem urgently requires more studies throughout the country to provide an accurate assessment

Kinetics and structure–activity relationship studies on pregnane-type steroidal alkaloids that inhibit cholinesterases

The mechanism of inhibition of acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BChE, EC 3.1.1.8) enzymes by 23 pregnane-type alkaloids isolated from the Sarcococca saligna was investigated. Lineweaver-Burk and Dixon plots and their secondary replots showed that the majority of these compounds, that is 1, 4, 5, 6, 9, 10, 12, 13, 15-19, and 21 were found to be noncompetitive inhibitors of both enzymes. Compounds 8, 20, 22, and 23 were determined to be uncompetitive inhibitors of BChE, while compounds 11 and 14 were found to be uncompetitive and linear mixed inhibitors of AChE, respectively. Ki values were found to be in the range of 2.65-250.0 microM against AChE and 1.63-30.0 microM against BChE. The structure-activity relationship (SAR) studies suggested that the major interaction of the enzyme-inhibitor complexes are due to hydrophobic and cation-pi interactions inside the aromatic gorge of these cholinesterases. The effects of various substituents on the activity of these compounds are also discussed in details.

The presence of dental fluorosis in the permanent dentition in Doha

The main purpose of this study is to draw attention to the presence and the severity of dental fluorosis in Doha (Qatar) through the high level of registered cases of fluorosis found among the groups examined. Of 4800 people aged 8-50 years, 2654 (55.29%) had dental fluorosis of some degree. This problem urgently requires more studies throughout the country to provide an accurate assessment.

Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some Turkish medicinal plants

The chloroform:medianol (1:1) extracts of a number of the plant species belonging to eight families, namely Corydalis solida (L.) Swartz subsp. solida and Glaucium corniculatum (L.) J. H. Rudolph (Papaveraceae), Rhododendron ponticum L. subsp. ponticum and Rhododendron luteum Sweet. (Ericaceae), Buxus sempervirens L. (Buxaceae), Vicia faba L. (Fabaceae), Robinia pseudoacacia L. (Caeselpiniaceae), Tribulus terrestris L. and Zygophyllum fabago L. (Zygophyllaceae), Lycopodium clavatum L. (Lycopodiaceae), Fumaria vaillantii Lois., Fumaria capreolata L., Fumaria kralikii Jordan, Fumaria asepala Boiss., Fumaria densiflora DC., Fumaria flabellata L., Fumaria petteri Reichb. subsp. thuretii (Boiss.) Pugsley, Fumaria macrocarpa Boiss. ex Hausskn., Fumaria cilicica Hauskkn., Fumaria parviflora Lam. and Fumaria judaica Boiss. (Fumariaceae) were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes by in vitro Ellman method at 10 microg/ml and 1 mg/ml concentrations. The extracts did not show any noticeable inhibitory activity against both of the enzymes at 10 microg/ml. The extracts of Rhododendron ponticum subsp. ponticum, Rhododendron luteum, Corydalis solida subsp. solida, Glaucium corniculatum, and Buxus sempervirens showed remarkable inhibitory activity above 50% inhibition rate on AChE at 1 mg/ml. Among them, Rhododendron ponticum subsp. ponticum, Corydalis solida subsp. solida and Buxus sempervirens were the most active extracts against BChE having 95.46 +/- 1.03%, 93.08 +/- 0.97%, and 93.45 +/- 0.88% inhibition rates, respectively. Among the extracts screened, all of the Fumaria extracts displayed highly potent inhibition against both of the enzymes at 1 mg/ml concentration compared to the standard.

Screening plant growth-promoting rhizobacteria for improving growth and yield of wheat

AIMS

Plant growth promoting rhizobacteria (PGPR) are commonly used as inoculants for improving the growth and yield of agricultural crops, however screening for the selection of effective PGPR strains is very critical. This study focuses on the screening of effective PGPR strains on the basis of their potential for in vitro auxin production and plant growth promoting activity under gnotobiotic conditions.

METHODS AND RESULTS

A large number of bacteria were isolated from the rhizosphere soil of wheat plants grown at different sites. Thirty isolates showing prolific growth on agar medium were selected and evaluated for their potential to produce auxins in vitro. Colorimetric analysis showed variable amount of auxins (ranging from 1.1 to 12.1 mg l-1) produced by the rhizobacteria in vitro and amendment of the culture media with l-tryptophan (l-TRP), further stimulated auxin biosynthesis (ranging from 1.8 to 24.8 mg l-1). HPLC analysis confirmed the presence of indole acetic acid (IAA) and indole acetamide (IAM) as the major auxins in the culture filtrates of these rhizobacteria. A series of laboratory experiments conducted on two cv. of wheat under gnotobiotic (axenic) conditions demonstrated increases in root elongation (up to 17.3%), root dry weight (up to 13.5%), shoot elongation (up to 37.7%) and shoot dry weight (up to 36.3%) of inoculated wheat seedlings. Linear positive correlation (r = 0.99) between in vitro auxin production and increase in growth parameters of inoculated seeds was found. Based upon auxin biosynthesis and growth-promoting activity, four isolates were selected and designated as plant growth-promoting rhizobacteria (PGPR). Auxin biosynthesis in sterilized vs nonsterilized soil inoculated with selected PGPR was also monitored that revealed superiority of the selected PGPR over indigenous microflora. Peat-based seed inoculation with selected PGPR isolates exhibited stimulatory effects on grain yields of tested wheat cv. in pot (up to 14.7% increase over control) and field experiments (up to 27.5% increase over control); however, the response varied with cv. and PGPR strains.

CONCLUSIONS

It was concluded that the strain, which produced the highest amount of auxins in nonsterilized soil, also caused maximum increase in growth and yield of both the wheat cv.

SIGNIFICANCE AND IMPACT OF STUDY

This study suggested that potential for auxin biosynthesis by rhizobacteria could be used as a tool for the screening of effective PGPR strains.

3D-QSAR Studies on natural acetylcholinesterase inhibitors of Sarcococca saligna by comparative molecular field analysis (CoMFA)

We have derived a comprehensive structure-activity relationship (SAR) picture for a new series of natural acetylcholinesterase inhibitors isolated from Sarcococca saligna. A set of 32 previously isolated and tested pregnane-type steroidal alkaloids inhibitors were investigated with respect to their IC(50) values (pIC(50)) against the AChE enzyme in order to derive CoMFA models using atom-based alignment. A highly significant CoMFA model was obtained with r(2) value of 0.974. The q(2) (cross validation r(2)) value also confirms the statistical significance of our model.