Deoxyribonucleic Acid Profiling Research Articles

Significance and challenges of DNA profiling in medicolegal setup of Pakistan

Deoxyribonucleic acid (DNA) serves as a unique genetic blueprint, inherited from our parents, making it an ideal identifier of individuals. The application of DNA analysis has revolutionized the field, leading to accurate and reliable results that have helped solve complex cases and bring justice to victims. This article focuses on the DNA-based reports in criminal justice system, as well as the accompanying challenges, emphasizing the necessity for particular DNA-based laws. The DNA discovery opened up new paths and the improvement of DNA identification and its incorporation into legal system has offered significant assistance in settlement of criminal and civil matters. Primarily, DNA proofing is used in a paternity dispute in Pakistan. Overall, the integration of DNA analysis into forensic science has significantly enhanced the process of investigating and resolving criminal cases. However, the necessity for laws and standards to allow its use for forensic reasons in Pakistan has long been recognized.

Genetic Biomarkers of Antipsychotic-Induced Prolongation of the QT Interval in Patients with Schizophrenia.

Antipsychotics (AP) induced prolongation of the QT interval in patients with schizophrenia (Sch) is an actual interdisciplinary problem as it increases the risk of sudden death syndrome. Long QT syndrome (LQTS) as a cardiac adverse drug reaction is a multifactorial symptomatic disorder, the development of which is influenced by modifying factors (APs' dose, duration of APs therapy, APs polytherapy, and monotherapy, etc.) and non-modifying factors (genetic predisposition, gender, age, etc.). The genetic predisposition to AP-induced LQTS may be due to several causes, including causal mutations in the genes responsible for monoheme forms of LQTS, single nucleotide variants (SNVs) of the candidate genes encoding voltage-dependent ion channels expressed both in the brain and in the heart, and SNVs of candidate genes encoding key enzymes of APs metabolism. This narrative review summarizes the results of genetic studies on AP-induced LQTS and proposes a new personalized approach to assessing the risk of its development (low, moderate, high). We recommend implementation in protocols of primary diagnosis of AP-induced LQTS and medication dispensary additional observations of the risk category of patients receiving APs, deoxyribonucleic acid profiling, regular electrocardiogram monitoring, and regular therapeutic drug monitoring of the blood APs levels.

An assessment of DNA extraction methods from blood-stained soil in forensic science

In forensic crime scene investigations, biological fluids such as blood are commonly found in soil. However, the analysis of blood-stained soil can be challenging due to the presence of inhibitors which limit the effective extraction and amplification of the deoxyribonucleic acid (DNA) required to produce a reportable DNA profile. There are some extraction methods that have been applied to blood-stained soil in forensic science, but these have produced sporadic results. This research has taken a number of different extraction methods from the fields of ancient DNA and environmental DNA and broken them down into the individual steps of pre-treatment, incubation, separation and purification. These steps were assessed independently then combined into various extraction methods to determine the best technique that can effectively and reliably profile human DNA from blood-stained soil. Testing involved assessment of three extraction buffers, (cetyltrimethylammonium bromide, guanidine thiocyanate, and proteinase K), four pre-treatment methods, (polyvinylpyrrolidone, ethylenediaminetetraacetic acid, hydrochloric acid, and sodium hydroxide), three separation steps, (centrifugation, phenol chloroform, and chloroform) and four purification steps, (size exclusion chromatography, bind elute columns, isopropanol precipitation and silica magnetic beads). The most effective procedure was found to be a polyvinylpyrrolidone pre-treatment with a proteinase K extraction buffer followed by magnetic silica bead purification with or without centrifugation. However, centrifugation separation was found to be equally effective after the pre-treatment step as after the incubation step. Our results shows that most of the current forensic procedures would benefit from the addition of a pre-treatment step prior to processing through the automated DNA profiling pipeline.

Lip print evaluation of Indian and Malaysian-Chinese subjects by manual and digital methods: a correlational study with gender and ethnicity

BackgroundCheiloscopy is a reliable method of personal identification which may augment the established methods like dactylography, DNA (deoxyribonucleic acid) profiling, and dental records.AimThis study aimed to determine the correlation of lip prints with ethnicity and gender of individuals in an attempt to bridge the gap between conventional manual methods and digital methods of cheiloscopy.MethodsLip prints of 300 gender-matched subjects of Indian and Malaysian-Chinese descents were collected and analyzed using the Suzuki K and Tsuchihashi Y classification system. The lip sizes were measured and lip print patterns were analyzed. The analysis was carried out using manual and computer-aided methods. A customized software for lip print analysis and validate it with the manual lip print analysis was developed.ResultsIndependent sample t test showed a statistically significant difference between the width and length of the lips between males and females of the total population (p < 0.001). Pearson’s chi-square test showed no statistically significant difference between the Indian males and females in the width of the lower lip (p = 0.074). In the Malaysian-Chinese population, there was a statistically significant difference between males and females in the length of the upper lip (p = 0.032) and lower lip (p = 0.035). The type V grooves were predominant in the total study population (51.3%) followed by type III pattern (38.7%). The new customized software could not provide reliable results.ConclusionsLip sizes differed significantly among the Indian and Malaysian-Chinese subjects. There was no significant gender dimorphism in the distribution of lip print patterns. The results from manual and computer-aided methods were comparable.

The current status of DNA fingerprinting procedures in criminal and civil investigations – an anthropological perspective

The discovery of DNA (Deoxyribo Nucleic Acid) is considered to be the greatest discovery which revolutionized the whole genetical analysis system straight away. This unique hereditary material is considered as one of the best ways of proofing scientific elements. Therefore, it can be directly utilized to identify victims and perpetrators in crime scene investigations and resolve civil cases. Even though DNA fingerprinting technology is utilized in Sri Lanka, criminal and civil investigations consumed more time and still delaying the results of the investigation procedures. Therefore, this research was conducted to find out the current status of DNA fingerprinting procedures in criminal and civil investigations in Sri Lanka. Secondary analysis and in-depth interview methods were used as a mode of data collection and the Government Analyst’s Department of Sri Lanka was selected as the study site based on the most recent DNA analyses, randomly selected 100 negative and positive DNA records were extracted from five different biological samples which cover up four different crimes and civil cases. Further, 08 scientists of the DNA Section were interviewed through an interview and data was analyzed via Microsoft Excel Application. It was revealed that blood and buccal cells are the most commonly used samples for DNA extractions and the majority of the cases have been matched with suspects and victims with 100% of accuracy in criminal and civil investigations. Contemporary DNA typing and profiling techniques are currently utilized in Sri Lanka and this department is not affected by any outside interferences and work independently. The current DNA fingerprinting technology has improved significantly and has a positive influence on criminal and civil investigations. However, the recommendations suggested by the DNA analysts should be considered and incorporate for the DNA fingerprinting technology to be successful in Sri Lanka. Further, public should be made aware of the benefits and the importance of DNA databases. In an anthropological perspective, a gradual increase in establishing parental and child support litigation can be recognized since DNA fingerprinting technology is the only way to prove such kind of incidents.

Secondary metabolites profiling of Vernonia amygdalina Del. in response to copper-induced abiotic stress

Background: Vernonia amygdalina is a green leafy vegetable that grows in tropical Africa and popularly cultivated in the southern part of Nigeria for its economic, nutritional and ethnomedicine value.Aims: This study analysed the influence of copper-induced abiotic stress on the deoxyribonucleic acid and secondary metabolites of V. amygdalina.Setting: Analyses of plant material were carried out in the Department of Botany, Lagos State University.Methods: Deoxyribonucleic acid (DNA) extraction and Inter Simple Sequence Repeat (ISSR) amplification were performed. Copper (Cu) concentration in leaves and stem of V. amygdalina was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES), secondary metabolites were determined using gas chromatography–mass spectrometry (GC-MS) and the effect on DNA amplification and profiling was analysed using gel electrophoresis.Results: After 41 days of cultivation, the stem of V. amygdalina significantly bioaccumulated 37 mg/L, 50 mg/L and 215 mg/L of Cu after spiking with 400 mg/L, 1000 mg/L and 2000 mg/L, respectively, whilst the leaves accumulated 52 mg/L, 100 mg/L and 350 mg/L of Cu, respectively. Copper-impregnated soil influenced phytochemicals of the plants by causing inconsistent increase and decrease in specific compounds such as levomenthol, methyl stearate and glycerine. Deoxyribonucleic acid bands of the stem and leaf of V. amygdalina from control site showed no band shift, whilst band shift occurred in the stem and leaf of the Cu-spiked V. amygdalina.Conclusion: This study revealed the leaves of V. amygdalina having higher Cu accumulation capacity than the stems. Also, Cu alters the quality and quantity of phytochemicals in plant parts.

Overview of Forensic DNA Profiling and Database

Deoxyribonucleic acid (DNA) profiling, has had a tremendous impact on forensic genetics. Before DNA profiling, all forensic genetic casework (e.g., Paternity testing, criminal casework, individual identification) was performed using classical serological genetic markers. Blood groups, human leukocyte antigen (HLA), and polymorphic protein and enzymes were used for solving forensic genetic casework using immunological and electrophoretic methodologies. These genetic markers were nevertheless limited when it was necessary to analyze minimal or degraded material, which is commonly involved in forensic cases. An STR is a region of human DNA containing an array of tandem repeats. Arrays range from only a 10 to about a hundred repeated units. This essay confers the basic concepts of operating of DNA in the criminal investigation. This review primarily summarizes the major tandem repeat markers used in forensic DNA profiling, that assist criminal’s conviction, exonerate the inferring individuals, and recognize victims of violence, catastrophes, and armed conflict.

Forensic DNA Profiling: Autosomal Short Tandem Repeat as a Prominent Marker in Crime Investigation.

Short tandem repeat (STR) typing continues to be the primary workhorse in forensic DNA profiling. Therefore, the present review discusses the prominent role of STR marker in criminal justice system. All over the world, deoxyribonucleic acid (DNA) profiling provides evidence that may be used to convict criminals, as an irrefutable proof of wrongful convictions, invaluable links to the actual perpetrators of crimes, and could also deter some offenders from committing more serious offences. Clearly, DNA profiling tools have also aided forensic scientists to re-evaluate old cases that were considered closed as a result of inadequate evidence. In carrying out this review, a comprehensive electronic literature search using PubMed, ScienceDirect, Google Scholar and Google Search were used, and all works meeting the subject matter were considered, including reviews, retrospective studies, observational studies and original articles. Case reports presented here, further demonstrates the crucial role of forensic DNA profiling in mitigating and providing compelling evidence for the resolution of crimes. For case report 1, there was a 100% match between the DNA recovered from the items found in the crime scene, and the suspect’s DNA sample collected via buccal swab following 15 STR loci examination. Case report 2 further highlights the indispensable contribution of DNA database in solving crime. Therefore, it has become very necessary for developing countries like Nigeria to develop a national DNA database and make policies and legislatures that will further expand and enable the practice of forensic genetics, particularly DNA profiling.

NET-02: A multi-center, randomised, phase II trial of liposomal irinotecan (nal-IRI) and 5-fluorouracil (5-FU)/folinic acid or docetaxel as second-line therapy in patients (pts) with progressive poorly differentiated extra-pulmonary neuroendocrine carcinoma (PD-EP-NEC).

TPS4158 Background: The prognosis for pts with PD-EP-NEC is poor. First-line treatment for advanced disease is etoposide/platinum-based chemotherapy, analogous to that of high grade lung NEC, with no standard second-line treatment, and is an area of unmet need. Methods: This is a multi-centre, randomised, phase II trial of nal-IRI; 80mg/m2 intravenously (IV) over 90 mins, prior to 5-FU; 2400 mg/m2 infusion over 46 hrs and folinic acid, Q14 days, or docetaxel; 75mg/m2 IV over 60 mins, Q21 days, as second-line therapy in pts with progressive PD-EP-NEC (Ki-67 &gt; 20%), with the overall aim of selecting a treatment for continuation to a phase III trial. The standard arm is that used in high-grade lung NEC, of which docetaxel is a second-line therapy option (NCCN guidelines) and combination regimens such as Irinotecan/5-FU are a second-line therapy option currently used without trial evidence for this subset of pts. Pts must have had prior treatment with first-line platinum-based chemotherapy, have documented disease progression and have an ECOG performance status of ≤2. This study plans to recruit 102 pts from 16 UK centres (over 37 mths). Primary endpoint is 6-mth progression-free survival (PFS) rate; trial is designed to have an 80% chance of demonstrating that the one-sided 95% confidence interval of the 6 mth PFS rate excludes 15%, if the true rate is at least 30%, where 30% is the required level of efficacy, and a rate of &lt; 15% would give grounds for rejection. If both treatment arms exceed the required level of efficacy to warrant further evaluation in a phase III trial, treatment with the higher PFS rate at 6 mths will be selected. Secondary endpoints include overall survival, objective response rate, toxicity, quality of life, serum neuron-specific enolase. Exploratory endpoints include quantification of circulating tumour cells (CTCs), circulating tumour deoxyribonucleic acid (ctDNA) and molecular profiling of CTCs, ctDNA and tumour tissue, and generation of CTC-derived xenografts. This trial is open and has enrolled 6 pts at time of submission. Clinical trial information: 10996604.

Oral Pathology in Forensic Investigation.

Forensic odontology is the subdiscipline of dentistry which analyses dental evidence in the interest of justice. Oral pathology is the subdiscipline of dentistry that deals with the pathology affecting the oral and maxillofacial regions. This subdiscipline is utilized for identification through oral and maxillofacial pathologies with associated syndromes, enamel rod patterns, sex determination using exfoliative cytology, identification from occlusal morphology of teeth, and deoxyribonucleic acid profiling from teeth. This subdiscipline is also utilized for age estimation studies which include Gustafson's method, incremental lines of Retzius, perikymata, natal line formation in teeth, neonatal line, racemization of collagen in dentin, cemental incremental lines, thickness of the cementum, and translucency of dentin. Even though the expertise of an oral pathologist is not taken in forensic investigations, this paper aims to discuss the role of oral pathology in forensic investigation.

Recent Advances in Forensic DNA Analysis

Forensic DNA (deoxyribonucleic acid) analysis or DNA profiling has played a major role in the criminal justice system. New techniques and technologies for DNA profiling continue to evolve every year. This paper reviews the literature reported during January 2011 through June 2013 in the field of forensic DNA analysis. Recent advances in almost all aspects of DNA analysis – which include sample collection, storage, and pretreatment, DNA extraction, DNA quantitation, quality assurance of DNA testing, and DNA databases are discussed. New developments now enable new kinds of forensically relevant information to be extracted from limited quantities of biological samples, and offer unprecedented potential for high-throughput DNA analysis.

Quality and Quantity of Extracted Deoxyribonucleic Acid (DNA) from Preserved Soft Tissues of Putrefied Unidentifiable Human Corpse

Context:The appropriate collection and preservation of soft tissues from putrefied unidentifiable human corpse for the purpose of identification using DNA profiling technique is critically important especially in developing countries like India having different levels of health-care set ups with largely varying facilities and varying climatic conditions.Aims:The present study was carried out, mainly focusing on quality and quantity of extracted DNA from the soft tissues of putrefied unidentifiable human corpse stored upto 4 weeks at 4°C and at −80°C for DNA analysis.Materials and Methods:The present study was conducted on 16 different putrefied unidentifiable human corpses after getting approval from institutional ethical committee. Around 2 g of four different tissues (brain, kidney, heart and muscle) were collected and preserved for one month followed by DNA extraction using the organic method, the quality and quantity of high molecular weight-DNA was estimated using the spectrophotometer and gel electrophoresis. Further, the amplification polymerase chain reaction (PCR) was also performed (AmpFLSTR® Indentifiler™ PCR Amplification kit for multiple loci, of Applied Biosystems, Lab India) and was checked using continuous PAGE.Results:The yield of DNA was significantly higher at −80°C for all the four tissues collected and was best for brain followed by heart, kidney and worst for muscles in all cases.Conclusions:It is suggested that the brain tissue preserved at −80°C is the best among soft issues for DNA extraction. Refrigeration or deep freezing facility should be available at all the centers.

Deoxyribonucleic acid profiling in forensic dental identification

Deoxyribonucleic acid profiling in forensic dental identification

Design and manufacture of surface textures on gun cartridge cases to trap DNA material

US and Australian work has shown that the effectiveness of extracting deoxyribonucleic acid (DNA) from standard gun cartridges is low and so analysis costs are high ( www.cci.gov/Reference/LpDNACtg_files ). The presence of greater than 1 ng of trapped bio-material would increase the success rates of DNA profiling and facilitate cheaper DNA analysis. The aim of this work is to increase the amount of recoverable DNA from a gun user deposited on fired cartridges, using microtextured surfaces as DNA receptors. Success would increase the probability of identifying perpetrators of gun crime through DNA matching. Various textures have been applied to flat surfaces of cartridge case material and the effects of those surface textures on trapping skin materials have been evaluated. In addition to treated/patterned surfaces, standard emery abrasive paper was adopted as a control medium. From the different surfaces tested, the emery abrasive paper was found to be most effective at trapping skin debris. Rough surfaces with pyramid textures, which are similar to features on emery paper, were subsequently manufactured on cartridge rims by a standard knurling process. Scratch tests were carried out to simulate the process of handling and loading these cartridges during the use of firearms. DNA test results of the knurled cartridges after firing, showed a high success rate of DNA profiling and high matching percentage to the donor's DNA profile.

Deoxyribonucleic Acid Profiling Analysis of 40 Human Thyroid Cancer Cell Lines Reveals Cross-Contamination Resulting in Cell Line Redundancy and Misidentification

Cell lines derived from human cancers provide critical tools to study disease mechanisms and develop novel therapies. Recent reports indicate that up to 36% of cell lines are cross- contaminated. We evaluated 40 reported thyroid cancer-derived cell lines using short tandem repeat and single nucleotide polymorphism array analysis. Only 23 of 40 cell lines tested have unique genetic profiles. The following groups of cell lines are likely derivatives of the same cell line: BHP5-16, BHP17-10, BHP14-9, and NPA87; BHP2-7, BHP10-3, BHP7-13, and TPC1; KAT5, KAT10, KAT4, KAT7, KAT50, KAK1, ARO81-1, and MRO87-1; and K1 and K2. The unique cell lines include BCPAP, KTC1, TT2609-C02, FTC133, ML1, WRO82-1, 8505C, SW1736, Cal-62, T235, T238, Uhth-104, ACT-1, HTh74, KAT18, TTA1, FRO81-2, HTh7, C643, BHT101, and KTC-2. The misidentified cell lines included the DRO90-1, which matched the melanoma-derived cell line, A-375. The ARO81-1 and its derivatives matched the HT-29 colon cancer cell line, and the NPA87 and its derivatives matched the M14/MDA-MB-435S melanoma cell line. TTF-1 and Pax-8 mRNA levels were determined in the unique cell lines. Many of these human cell lines have been widely used in the thyroid cancer field for the past 20 yr and are not only redundant, but not of thyroid origin. These results emphasize the importance of cell line integrity, and provide the short tandem repeat profiles for a panel of thyroid cancer cell lines that can be used as a reference for comparison of cell lines from other laboratories.

Biodegradation of methyl t-butyl ether by aerobic granules under a cosubstrate condition

Aerobic granules efficient at degrading methyl tert-butyl ether (MTBE) with ethanol as a cosubstrate were successfully developed in a well-mixed sequencing batch reactor (SBR). Aerobic granules were first observed about 100 days after reactor startup. Treatment efficiency of MTBE in the reactor during stable operation exceeded 99.9%, and effluent MTBE was in the range of 15-50 microg/L. The specific MTBE degradation rate was observed to increase with increasing MTBE initial concentration from 25 to 500 mg/L, which peaked at 22.7 mg MTBE/g (volatile suspended solids).h and declined with further increases in MTBE concentration as substrate inhibition effects became significant. Microbial-community deoxyribonucleic acid profiling was carried out using denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal ribonucleic acid. The reactor was found to be inhabited by several diverse bacterial species, most notably microorganisms related to the genera Sphingomonas, Methylobacterium, and Hyphomicrobium vulgare. These organisms were previously reported to be associated with MTBE biodegradation. A majority of the bands in the reactor represented a group of organisms belonging to the Flavobacteria-Proteobacteria-Actinobacteridae class of bacteria. This study demonstrates that MTBE can be effectively degraded by aerobic granules under a cosubstrate condition and gives insight into the microorganisms potentially involved in the process.

PROPERTIES OF A UNIQUE MUTANT OF HELICOVERPA ARMIGERA SINGLE-NUCLEOCAPSID NUCLEOPOLYHEDROVIRUS THAT EXHIBITS A PARTIAL MANY POLYHEDRA AND FEW POLYHEDRA PHENOTYPE ON EXTENDED SERIAL PASSAGING IN SUSPENSION CELL CULTURES

Serial passaging of wild-type Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) in H. zea (Hz-AM1) insect cell cultures results in rapid selection for the few polyhedra (FP) phenotype. A unique HaSNPV mutant (ppC19) was isolated through plaque purification that exhibited a partial many polyhedra (MP) and FP phenotype. On serial passaging in suspension cell cultures, ppC19 produced fivefold more polyhedra than a typical FP mutant (FP8AS) but threefold less polyhedra than the wild-type virus. Most importantly, the polyhedra of ppC19 exhibited MP-like virion occlusion. Furthermore, ppC19 produced the same amount of budded virus (BV) as the FP mutant, which was fivefold higher than that of the wild-type virus. This selective advantage was likely to explain its relative stability in polyhedra production for six passages when compared with the wild-type virus. However, subsequent passaging of ppC19 resulted in a steep decline in both BV and polyhedra yields, which was also experienced by FP8AS and the wild-type virus at high passage numbers. Genomic deoxyribonucleic acid profiling of the latter suggested that defective interfering particles (DIPs) were implicated in this phenomenon and represented another undesirable mutation during serial passaging of HaSNPV. Hence, a strategy to isolate HaSNPV clones that exhibited MP-like polyhedra production but FP-like BV production, coupled with low multiplicities of infection during scale-up to avoid accumulation of DIPs, could prove commercially invaluable.

Pulsed-Field Fingerprinting of Vaginal Group B Streptococcus in Pregnancy

In Brief OBJECTIVE There is more to be learned about the epidemiology of group B β-hemolytic streptococci infections in pregnancy. In this study, we investigated the discriminating capabilities of pulsed-field gel electrophoresis of group B streptococci strains from pregnant patients and mother/infant pairs of patients compared with serotyping. METHODS Forty-two vaginal strains of group B streptococci cultured from pregnant patients in the third trimester and strains from 20 mother/infant pairs with documented newborn group B streptococci infection were studied. Isolates were serotyped by the Lancefield capillary precipitin method and molecularly characterized by counterclamped homogeneous electrical field pulsed-field gel electrophoresis with rarely cutting restriction enzymes. RESULTS Nine of the 13 serotypes of group B streptococci identified thus far in the scientific literature (Ia, Ia/c, Ib, Ib/c, II, IIc, III, V, and NT/c) were represented among the 62 isolates. Among the 42 maternal isolates, eight serotypes were represented, and among the 20 mother/infant isolates, six serotypes were represented. Serotypes of mother/infant isolates matched in nine of the ten pairs. Restriction endonuclease profiles, or digests, from the 42 maternal isolates resulted in 25 unique profiles that were arranged into five major groups based on the overall relatedness. Each group was comprised of one predominant serotype. The 20 mother/infant paired isolates displayed nine unique restriction endonuclease profiles and nine of the ten paired isolates showed indistinguishable restriction endonuclease profiles between mother and infant. CONCLUSION Deoxyribonucleic acid profiling using pulsed-field gel electrophoresis is more discriminating of group B streptococci strains than serotyping because of the different yet closely related patterns within each restriction endonuclease profile group that are linked to one specific serotype. Pulsed-field gel electrophoresis can refine our epidemiologic studies of group B streptococci transmission and acquisition. Pulsed-field gel electrophoresis of group B streptococci is more discriminating than serotyping.

Pulsed-field fingerprinting of vaginal group B streptococcus in pregnancy

OBJECTIVE: There is more to be learned about the epidemiology of group B β-hemolytic streptococci infections in pregnancy. In this study, we investigated the discriminating capabilities of pulsed-field gel electrophoresis of group B streptococci strains from pregnant patients and mother/infant pairs of patients compared with serotyping. METHODS: Forty-two vaginal strains of group B streptococci cultured from pregnant patients in the third trimester and strains from 20 mother/infant pairs with documented newborn group B streptococci infection were studied. Isolates were serotyped by the Lancefield capillary precipitin method and molecularly characterized by counterclamped homogeneous electrical field pulsed-field gel electrophoresis with rarely cutting restriction enzymes. RESULTS: Nine of the 13 serotypes of group B streptococci identified thus far in the scientific literature (Ia, Ia/c, Ib, Ib/c, II, IIc, III, V, and NT/c) were represented among the 62 isolates. Among the 42 maternal isolates, eight serotypes were represented, and among the 20 mother/infant isolates, six serotypes were represented. Serotypes of mother/infant isolates matched in nine of the ten pairs. Restriction endonuclease profiles, or digests, from the 42 maternal isolates resulted in 25 unique profiles that were arranged into five major groups based on the overall relatedness. Each group was comprised of one predominant serotype. The 20 mother/infant paired isolates displayed nine unique restriction endonuclease profiles and nine of the ten paired isolates showed indistinguishable restriction endonuclease profiles between mother and infant. CONCLUSION: Deoxyribonucleic acid profiling using pulsed-field gel electrophoresis is more discriminating of group B streptococci strains than serotyping because of the different yet closely related patterns within each restriction endonuclease profile group that are linked to one specific serotype. Pulsed-field gel electrophoresis can refine our epidemiologic studies of group B streptococci transmission and acquisition.

Extent of digestion affects the success of amplifying human DNA from blood meals of Anopheles gambiae (Diptera: Culicidae).

The success of distinguishing blood meal sources of Anopheles gambiae Giles through deoxyribonucleic acid (DNA) profiling was investigated by polymerase chain reaction (PCR) amplification at the TC-11 and VWA human short tandem repeats (STR) loci. Blood meal size and locus had no significant effect on the success of amplifying human DNA from blood meals digested for 0, 8, 16, 24 and 32 h (P = 0.85 and 0.26 respectively). However, logistic regression found a significant negative relationship between time since ingestion and the success probability of obtaining positive PCR products among meals digested for between 8 and 32 h (P = 0.001). Approximately 80% of fresh blood meals were successfully profiled. After 8 h, the proportion of blood meals that could be successfully profiled decreased slowly with time after ingestion, dropping to below 50% after approximately 15 h. There was no significant difference in the success of amplifying human DNA from blood meals of mosquitoes killed at time 0 and 8 h after ingestion (P = 0.272).