Establishment of an in vitro regeneration system for genetic transformation of selected sugarcane genotypes

A good culture system provides considerable quantities of highly regenerable target tissues. Embryogenic callus cultures are ideal for micro-projectile-mediated transformation, because regenerable cells are not very stable. Effective exploitation of genetic transformation requires good regeneration systems. We selected three sugarcane genotypes for the establishment and optimization of good in vitro regeneration systems, viz., S-2003-us-359, S-2006-sp-30, and S-2003-us-165. Three callus induction media were investigated. These media were composed of Murashige and Skoog (MS) medium salt plus 1, 2, and 3 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D). Medium with 3 mg/L 2,4-D gave the greatest mass of embryogenic calli. The calli produced on the three callus induction media were transferred to 18 types of regeneration media (RM1-RM18). They varied with respect to plant growth regulators and sucrose levels but the basal medium was MS. Two levels of sucrose (30 and 40 g/L), three levels of 2,4-D (0.1, 0.25, 0.5 mg/L) and three levels of 6-benzylaminopurine (0, 0.25 and 0.5 mg/L) were studied in the regeneration media. The effects of callus age on regeneration were evaluated by transferring the calli to regeneration media after 15, 21, 28, and 35 days of culture. The 21-day-old callus of the genotype S-2003-us-359 on RM3 yielded the largest number of plants and was selected as the best for transformation. Six RAPD DNA primers were used to check genetic stability; this medium did not affect the sugarcane genomes.

Development of a species-specific sequence-characterized amplified region marker for roses

DNA fingerprints of four rose species, Rosa centifolia, R. Gruss-an-Teplitz, R. bourboniana, and R. damascena, were developed using RAPD-PCR. We identified a unique polymorphic band in R. centifolia. This 762-bp fragment was produced by the random primer GLI-2. The fragment was eluted and directly cloned in a TA cloning vector, pTZ57R/T. Digestion of the plasmid with EcoRI confirmed the cloning of GLI-2(762) in pTZ57R/T. A second enzyme, PstI, used in combination with EcoRI, gave complete digestion of the plasmid, and the 762-bp fragment was confirmed on the gel. Subsequently, the polymorphic amplicon was sequenced with an AB1 373 DNA sequencer system using the PRISM(TM) Ready Reaction DyeDeoxy(TM) Terminator Cycle Sequencing kit. After sequencing, specific primers (23 bp long) were designed based on the sequence of the flanking regions of the original RAPD fragment. These primers will effectively allow fingerprinting for the identification of R. centifolia species. In essence, we developed an SCAR marker to authenticate the identity of R. centifolia species and to distinguish it from its substitutes. Such techniques are required not only to complement conventional parameters in creating the passport data of commercial and medicinal products of rose, but also for routine quality control in commercial and government rosaries and rose nurseries.

Immunohistochemical evaluation of p53, FHIT, and IGF2 gene expression in esophageal cancer

The aim of the study was to evaluate the expression of tumor suppressor genes p53, fragile histidine triad gene (FHIT), and an oncogene insulin-like growth factor 2 (IGF2) as prognostic markers in the etiology of esophageal cancer. Immunohistochemistry (IHC) was performed in 39 archival tissue samples of different esophageal pathologies for the three genes. Abnormal p53 expression was maximum in all the cases of squamous cell carcinoma, while IGF2 expression was enhanced in squamous cell carcinoma (81%), adenocarcinoma (100%), and dysplasia of squamous epithelium (75%) samples when compared with normals (50%). To our surprise, 75% of normal tissues did not show FHIT expression, which was also not seen in 40% of dysplasias of squamous epithelium, 33.3% of adenocarcinoma, and 41% of squamous cell carcinoma. To the best of our knowledge, this is the first study evaluating IGF2 by IHC, as well as, correlating it with the expression of the two tumor suppressor genes, p53 and FHIT, in esophageal tissue. p53 expression was threefold higher than normal in dysplasias of squamous epithelium and adenocarcinoma, while it was eightfold higher in squamous cell carcinoma. IGF2 expression was low in normal and dysplasia tissue but was increased 1.97-fold in both types of malignancy. FHIT and p53 expression were well correlated in squamous cell carcinoma, supporting the observation that FHIT regulates and stabilizes p53. Altered/lowered FHIT levels may be a result of exposure to various exogenous agents; however, this could not be assessed in the present study as it was carried out on archival samples. A larger prospective study is warranted to establish the role of exogenous factors in FHIT expression.

Further insights into the strange role of bacterial endosymbionts in whitefly, Bemisia tabaci: comparison of secondary symbionts from biotypes B and Q in China

The percentage infection of secondary symbionts (SS) (Wolbachia, Arsenophonus, Rickettsia, Hamiltonella, Fritschea and Cardinium) in the exotic Bemisia tabaci (Genn.) invaders, commonly known as biotypes B and Q from China, were determined by PCR. In total, 373 biotype B and 1830 biotype Q individuals were screened for the presence of SS. Biotype B was more abundant than biotype Q from 2005 to 2006, and biotype Q was more abundant from 2007 to 2009. Each of the SS, with the exception of Fritschea, was detected in both biotypes B and Q; Fritschea was found in none of the samples examined. For biotype B, the percentage infection of Hamiltonella was the highest (92.0%) followed by Rickettsia (70.2%). For biotype Q, the percentage infection of Hamiltonella was again the highest (73.3%). Arsenophonus was the least common of the SS observed in both biotypes B and Q. The percentage infection of Wolbachia, Rickettsia and Hamiltonella in biotype B was each significantly higher than in biotype Q, whereas the percentage infection of Cardinium in biotype B was significantly lower than in biotype Q. The percentage infection of SS in biotypes B and Q varied from year to year over the period 2005-2009. Furthermore, within biotype Q, two distinct subgroups were identified which differ from each other in terms of their SS complement. We discuss these results in the light of the potentially influential factors and roles of the SS.

Expressed sequence tag-simple sequence repeat-based molecular variance in two Salicornia (Amaranthaceae) populations

Salicornia spp is one of the most salt-tolerant vascular plants and is native to salt marshes and estuaries. We developed expressed sequence tag derived-simple sequence repeat (EST-SSR) markers for estimating genetic diversity and marker-assisted Salicornia breeding. Six polymorphic EST-SSRs of 40 detected 27 alleles, ranging from three to five alleles per locus. The average number of alleles per locus was 4.33 and 4.17, and the major allele frequency at locus DY529765 was high, being 0.859 and 0.857 in S. bigelovii and S. europea, respectively. Gene diversity, heterozygosity and polymorphism information content were highest at locus DY529950 and similar in these two species. Gene diversity increased with increase in the number of alleles that had a low major allele frequency at a locus. Six polymorphic loci effectively discriminated 46 taxa into three clusters via different analyses. Significant deviation of F(ST) from zero in three suggested populations for six loci indicated population differentiation and limited gene flow among them. A reduced median network established that taxon SB65 is primitive. SMART (simple modular architecture research tool) analysis of peptide sequences of six EST-SSRs showed that loci DY529765, DY529950 and EC906203 contained transmembrane, TLC, AgrB and NTR domains and might be involved in salinity stress tolerance. These EST-SSRs are a valuable resource for marker development and may be useful in marker-assisted Salicornia breeding.

Elucidation of thermotolerance diversity in cotton (Gossypium hirsutum L.) using physio-molecular approaches

Cotton (Gossypium hirsutum) is an important cash crop, but high temperature during its growing season is one of the major factors that limit its productivity. This problem compels plant breeders to breed for heat tolerance, which can help to overcome this challenge. It is very important to make a comprehensive screening of heat-tolerant genotypes so that only the best are chosen. Here we report the combined use of several techniques that can help breeders to screen their germplasm. Twelve cultivated cotton genotypes were evaluated for thermotolerance, using assays that included electrolyte leakage, chlorophyll accumulation and protein profiling, as well as RAPDs to assess genetic diversity. Two genotypes (B-557 and NIAB-78) showed tolerant behavior in three thermotolerance assays. RAPD analysis results showed maximum similarity in a range of 86.7-66.7% between the genotypes MNH-554 and CIM-443. We conclude that combined use should be made of relative electrolyte leakage, chlorophyll stability and differential display with SDS-PAGE to aid in screening for stress tolerance. RAPD-based diversity analysis will further help to improve the efficiency of breeding programs.

Genotoxicity in agricultural farmers from Guntur district of South India—A case study

Background: Pesticides play an important role in controlling the pests on agricultural crops and thereby to increase the yield of agricultural produce. Farmers occupationally exposed to pesticides during spraying activities are more prone to genotoxicity than unexposed. Aim: To assess the genotoxicity in farmers, engaged in spraying complex mixture of pesticides in the cultivation of cotton crops. Material and methods: A total number of 152 male subjects were selected randomly from Guntur district of Andhra Pradesh (AP), South India. The demographic particulars viz., personal habits, duration of exposure to pesticides, types of pesticides used were collected from the study subjects using an interview schedule. Among them 76 subjects were farmers and the remaining individuals served as unexposed or controls. Blood samples from these subjects were collected for assessing the genetic damage by chromosomal aberrations (CAs) test and micronucleus test (MNT). Results: The results of the study indicated that CA was significantly higher with 2.8% in farmers who were exposed to pesticides when compared to unexposed (0.72%). However, there was a minor difference in MN with 0.13% and 0.12% between exposed and unexposed which was not statistically significant ( p < 0.05). Conclusion: A correlation between CA frequency and exposure to benzene hexachloride (BHC) pesticide residue was observed.

Estimation of genetic distance based on RAPDs between 11 cotton accessions varying in heat tolerance

The genetic distance of 11 cotton genotypes varying in heat tolerance was studied using RAPD markers. Fifty-three random decamer primers were used for the estimation of genetic distance. Among the 53 RAPD primers, which were custom synthesized by GeneLink Inc., UK, 32 were polymorphic and 21 were monomorphic. The 32 polymorphic primers produced 273 fragments, with a mean of 8.3 fragments per primer. The number of polymorphic bands produced in the 11 cotton accessions ranged from 1 to 31. Primer GLC-20 produced 31 polymorphic bands, while two primers, GLB-5 and GLC-12, produced one polymorphic band each. A range of 88.89 to 42.48% genetic similarity was observed among the 11 cotton accessions. The highest genetic similarity was observed between FH-945 and BH-160 (88.89%), whereas the lowest value was found between NIAB-801/2 and FH-945 (42.48%). Unique amplification profiles were produced by most of the cultivars; the differences were sufficient to distinguish them from other genotypes. This confirms the efficacy of RAPD markers for the identification of plant genotypes. An accumulative analysis of amplified products generated by RAPDs was sufficient to assess the genetic diversity among the genotypes. This information should be helpful for formulating breeding and genome mapping programs.

Safe blood transfusion practices in blood banks of Karachi, Pakistan

BACKGROUND

Since 1997, legislations pertaining to safe blood transfusion (SBT) have evolved considerably in Pakistan. The objective of this study was to evaluate the SBT practices in the blood banks of Pakistan.

METHODS

Twenty-three blood banks were randomly selected from a list of registered 40 in Karachi, the largest city in Pakistan. To evaluate the SBT practices in the selected blood banks, a questionnaire and a checklist were administered during 2007-2008.

RESULTS

Of the 23 blood banks surveyed, 4 (17%) were affiliated with government or a semi-government institution; 16 (70%) blood banks had a healthy donor recruitment program and 2 (9%) of the blood banks agreed that they recruited remunerated (paid) blood donors. Donors were screened for HIV, Hepatitis B, Hepatitis C and syphilis by all 23 blood banks, whereas malaria was screened by all blood banks but one.

CONCLUSION

SBT practices in Karachi have improved since 1995; an active role by the government in policy-making has proven effective.

Efficient mycobacterial DNA extraction from clinical samples for early diagnosis of tuberculosis

BACKGROUND

Polymerase chain reaction (PCR) detection of Mycobacterium tuberculosis in clinical samples requires the use of an extraction method that can efficiently lyse mycobacterial cells and recover small amounts of DNA.

OBJECTIVE

To evaluate the use of a benzyl-alcohol guanidine hydrochloride (DNA extraction) method (GuHClM) on blood samples.

DESIGN

GuHClM was evaluated in quantitatively spiked blood samples with M. tuberculosis. We assessed the insertion sequence (IS) 6110 region of M. tuberculosis to evaluate the efficacy of the method. The method was also applied on 102 clinical samples of suspected tuberculosis (TB) individuals and compared with smear microscopy of sputum specimens and the results of cultures.

RESULTS

This method reproducibly detected as low as 4-6 bacilli. Of 102 clinical samples, 84 were human immunodeficiency virus (HIV) negative, while 18 were HIV-positive. Among the HIV-negative individuals, 58.3% were TB-positive using PCR, while respectively 47.6% and 45.2% were sputum- and culture-positive. Among the HIV-positive individuals, 55.6% were PCR-positive, whereas only 38.9% were sputum-positive and 50% were culture-positive.

CONCLUSION

These results demonstrate that the identification of mycobacteria by PCR using GuHClM is very sensitive and therefore may have wide utility in the diagnosis of TB.

Platelet count in 100 cases of pregnancy induced hypertension

Hypertensive disorders are most common medical complication of pregnancy and the major causes of maternal & perinatal disease and death worldwide. The aim of the study was to see the platelet count in pregnancy induced hypertension (PIH). It was a prospective study. The study was done on 100 cases of PIH patients in Gynae & Obstetrics department of Mymensingh Medical College Hospital (MMCH) during the period of January to July 2006. Among the 100 cases 60 were eclamptic, 34 were pre eclamptic (PE) and 06 were gestational hypertensive (GH) patients. All the necessary informations and data were collected by interviewing the patients or their attendants on a pre-designed data collection sheet. Blood sample were collected from the patients and required investigations were done. Most of the eclampsia cases were from below average socioeconomic status of family, and other two groups were from average socioeconomic status of family. Among eclamptic patients 76.60% were primigravida. In eclamptic group 93.33% did not get any antenatal care but 83.33% GH cases had regular antenatal care. Among the eclamptic group mean maternal age was 23.12 years. In our study 47.00% had low platelet count (<1,50,000/cmm). Among eclampsia group 60.00% had low platelet count (<1,50,000/cmm). In our study 12% cases developed postpartum haemorrhage (PPH) and among them 66.67% had low platelet count (<1,50,000/cmm). Although there is chance of development of disseminated intravascular coagulation (DIC) and Liver Failure in patients with low platelet count, but in our study there is no such incidence. In our study mortality was 3% and all were in eclamptic group. Those patients had low platelet count 74.28% had low birth weight (LBW) babies. Platelet count is a very important investigation for antenatal mother having PIH, as it is directly related to maternal and perinatal outcome.

Estimation of genetic distance between 10 maize accessions with varying response to different levels of soil moisture

Ten maize accessions (NC-9, A50-2, M-14, B-42, NC-3, T-7, N-48-1, B-34, USSR, and WFTMS) were studied to estimate the genetic distance on molecular level by random amplified polymorphic DNA. These accessions were selected on the basis of their variable responses against different levels of moisture. Twenty-five primers were used to test genetic diversity, of which 14 were observed to be polymorphic. Ninety-three loci were amplified; among these, 77 showed polymorphism and the other 16 were monomorphic. Primers A-13 and C-02 gave the most polymorphic bands, while primers A-01 and C-06 gave the fewest polymorphic bands. The genetic similarities of the 10 maize accessions ranged from 82.8 to 54.8%. Accessions USSR and WFTMS showed greatest similarity, and accessions M-14 and B-42 were found more dissimilar than the other accessions. On the basis of cluster analysis, these 10 accessions were classified in two major groups, A and B, and than further divided into sub-groups. The cluster analysis showed that accessions in the same group as well as in the sub-groups were similar in their physical and morphological characters, since the characters are controlled genetically.

Molecular characterization of wheat germplasm using microsatellite markers

We investigated the genetic diversity of 63 wheat genotypes, composed of 48 accessions and 15 varieties, using 56 polymorphic simple sequence repeat primers. One hundred and eighty-six loci were found, with a mean of 131.26 alleles per locus. Cluster analysis based on microsatellite allelic diversity discriminated the accessions and varieties into different clusters; genetic diversity was the highest between variety Kohistan-97 and accession number 011512, giving a genetic similarity value of 0.4198. Accession numbers 011484 and 011356 gave a genetic similarity value of 0.9589, indicating that these accessions were 95.89% similar. We found that microsatellite markers could characterize and discriminate all of the genotypes; more primers could be used for saturation of different regions in further studies.

Resolution of ST-segment elevation after streptokinase therapy in anterior versus inferior wall myocardial infarction

BACKGROUND

Resolution of ST-segment elevation is the best bedside predictor of myocardial reperfusion.

HYPOTHESIS

This study was conducted to examine the resolution of ST-segment elevation after streptokinase therapy in anterior versus inferior acute myocardial infarction (MI) and to corroborate it with echocardiographic and coronary angiographic data.

METHODS

The study population consisted of 70 patients, 35 each in the anterior and inferior MI groups. The electrocardiograms (ECGs) were recorded before, on completion of, and on Days 1 and 2 post streptokinase therapy. The resolution of ST segment determined from post-streptokinase ECGs was compared between the two groups and correlated with echocardiographic and coronary angiographic data.

RESULTS

On completion of and on Day 1 post streptokinase therapy, ST-segment resolution in both groups was not significantly different. On Day 2 post streptokinase therapy, resolution of the ST segment per lead was significantly lower in anterior than that in inferior MI (61 +/- 21% anterior vs. 77 +/- 21% inferior, p 0.003). The number of patients with akinesis of infarct-related ventricular wall was significantly higher (17 anterior vs. 7 inferior, p 0.02), and left ventricular ejection fraction was significantly lower in anterior MI (39 +/- 7% anterior vs. 48 +/- 8% inferior, p < 0.01). There was no significant difference in coronary angiographic data. One patient in each group demonstrated normal coronary arteries.

CONCLUSIONS

The resolution of ST-segment elevation on the completion of and on Day 1 post streptokinase therapy was comparable between anterior and inferior MI. The significantly less frequent resolution of ST-segment elevation in anterior MI on Day 2 post streptokinase could be due to more akinesis, larger infarct size, and worse systolic function rather than due to failure to open the infarct-related vessel.

Worsening of left ventricular diastolic dysfunction during exercise causes decreased exercise tolerance in hypertension

BACKGROUND

Exercise tolerance is reduced in hypertension. Hypertension affects left ventricular (LV) diastolic filling by causing abnormal relaxation and decreasing compliance.

HYPOTHESIS

This study was designed to determine whether worsening of LV diastolic dysfunction during exercise causes decreased exercise tolerance in hypertension.

METHODS

Left ventricular diastolic filling parameters were examined at mitral valve by Doppler echocardiography at rest and at peak exercise in hypertensive patients and were compared with those of age- and gender-matched normotensive individuals. Treadmill exercise stress test was performed according to the Bruce protocol and the exercise time was recorded.

RESULTS

Exercise time was significantly shorter in the hypertensive group than that in the normotensive group (320 +/- 29 vs. 446 +/- 38 s, p 0.03). The hypertensive group demonstrated abnormal relaxation pattern of diastolic mitral inflow at rest, which became pseudonormal at peak exercise (E/A velocity ratio, rest 0.86 +/- 0.06 vs. exercise 1.19 +/- 0.09, p < 0.001). The diastolic mitral inflow pattern remained normal at peak exercise in the normotensive group. The deceleration time and the pressure half time of early mitral inflow at peak exercise were significantly shorter in the hypertensive group than those in the normotensive group (deceleration time, 182 +/- 20 vs. 238 +/- 22 ms, p 0.02: pressure half time, 54 +/- 5 vs. 70 +/- 12 ms, p 0.01).

CONCLUSIONS

This study demonstrates that reduced exercise tolerance in hypertension is associated with worsening of diastolic dysfunction during exercise consistent with an increase in left atrial pressure.

Estimation of genetic diversity among sunflower genotypes through random amplified polymorphic DNA analysis

The genetic diversity among eight sunflower lines was determined through the estimation of the random amplified polymorphic DNA method. One hundred and fifty-six DNA fragments were generated by 20 random primers, for an average of about 7.8 bands per primer. Of these amplified DNA fragments, 104 were polymorphic among the eight sunflower lines. Nei and Li's similarity matrix gave values from 51.59 to 77.78%, which indicated a broad genetic base. The maximum similarity, 77.78%, was observed between R-SIN-82 and RN-46. The lowest similarity, 51.59%, was observed between the exotic lines CM-612 and HA-27. After knowing the knowledge of genetic diversity based on these random amplified polymorphic DNA markers, highly diverse lines can be used for further breeding programs to develop an ideal local hybrid of sunflower.

Transport of sennosides and sennidines from Cassia angustifolia and Cassia senna across Caco-2 monolayers--an in vitro model for intestinal absorption

Laxative effects of Senna preparations are mainly mediated by rheinanthrone, a metabolite formed in the intestinal flora from dianthrones. Nevertheless, it was not clear whether dianthrones are bioavailable at all and contribute to the overall effects of this important medicinal plant. Using the Caco-2 human colonic cell line as an in vitro model of the human intestinal mucosal barrier, the bioavailability of dianthrones was studied in apical to basolateral (absorptive) and basolateral to apical (secretive) direction. Permeability coefficients (P(c)) and percent transport were calculated based on quantitations by HPLC. From the data obtained it was concluded that sennosides A and B, as well as their aglycones sennidine A and B are transported through the Caco-2 monolayers in a concentration-dependent manner and their transport was linear with time. The absorption in apical to basolateral direction was poor and P(c) values were comparable to mannitol. The transport was higher in the secretory direction, indicating a significant efflux (e.g. by efflux pumps) of the (poorly) absorbed compounds in the intestinal lumen again. Our findings support the general understanding that the laxative effects of Senna are explainable mainly by metabolites and not by the natively present dianthrones.

A coupled drug kinetics-cell cycle model to analyse the response of human cells to intervention by topotecan

A model describing the response of the growth of single human cells in the absence and presence of the anti-cancer agent topotecan (TPT) is presented. The model includes a novel coupling of both the kinetics of TPT and cell cycle responses to the agent. By linking the models in this way, rather than using separate (disjoint) approaches, it is possible to illustrate how the drug perturbs the cell cycle. The model is compared to experimental in vitro cell cycle response data (comprising single cell descriptors for molecular and behavioural events), showing good qualitative agreement for a range of TPT dose levels.

Quantitative determination of vasicine and vasicinone in Adhatoda vasica by high performance capillary electrophoresis

A new method of capillary electrophoresis was developed for the quantitative determination of vasicine and vasicinone from Adhatoda vasica (L.) Nees. The electrophoretic separation was performed using a 47 cm x 50 microm ID (38.5 cm effective length) fused silica capillary. The samples were injected by pressure for 3 s at 50 mbar and the running voltage was 19 kV at the injector end of the capillary. The capillary temperature was maintained at 40 degrees C. The separation of the two alkaloids has been achieved within 11 min with good repeatability. The method was validated in terms of reproducibility, linearity, accuracy and applied for the quantitative determination of vasicine and vasicinone in A. vasica plant samples/extracts. Parameters affecting the resolution such as pH, temperature, organic modifier, buffer concentration and capillary dimensions were reported.

Study of genetic divergence among wheat genotypes through random amplified polymorphic DNA

The degree of genetic divergence was estimated in seven wheat genotypes, six exotic genotypes and one local variety, through random amplified polymorphic DNA methodology. A total of 112 DNA fragments were generated by the 15 random primers, with an average of about 7.4 bands per primer. Among the 112, 50 fragments showed polymorphism among the seven wheat genotypes. Nei and Li's similarity matrix ranged from 86.2 to 93.0%, which indicated a narrow genetic base among the genotypes. The maximum similarity, 93.0%, was observed between 12WLRG/1-12 and WL-43. The local variety, Chenab-70, showed the lowest similarity with the exotic types. We conclude that random amplified polymorphic DNA analysis can be used for the characterization and grouping of wheat genotypes; these results will be helpful in our wheat breeding program.