植物孢粉的研究方法在司法鉴定中的应用

植物孢粉,是指植物的孢子和花粉,属于"孢粉学"的研究范畴。植物孢粉在自然界分布很广,密切地伴随着人类的各种活动,容易与多种诉讼活动发生联系而成为证据。在实际案件中,植物孢粉的利用率很低,反映人们对植物孢粉研究成果及其作用认识不够,缺乏对司法孢粉检验技术的相关研究。为此,对植物孢粉的形态检验方法、孢子花粉壁的构造和纹饰检验方法、地层中植物孢粉的提取方法进行了分析;对植物孢粉的研究方法在司法鉴定中的应用价值进行探讨,以期为司法孢粉检验技术的建立提供参考。     

A Rapid and Efficient Method for Evaluation of Suspect Testimony: Palynological Scanning

A rapid method for evaluating suspect testimony is valuable at any stage in an inquiry and can result in a change of direction in an investigation. Rape cases, in particular, can present problems where a defendant renders DNA analysis redundant by claiming that the claimant consented to have sexual relations. Forensic palynology is valuable in confirming or eliminating locations as being crime scenes, thus checking the testimony of both parties. In contrast to some forensic disciplines, forensic palynology can provide critical information without time-consuming full analysis. Two cases are described where the palynological assemblages from comparator samples of pertinent places were compared with those obtained from clothing of claimants and defendants. The results of rapid microscopical scanning of relevant preparations led to early confessions, thus obviating the need for costly analyses and protracted court proceedings. A third case demonstrates the unbiased nature of this technique where a man, although innocent of any offense, lied about having visited the crime scene for fear of prosecution. This highlights the need for sensitive policing in claims of rape.     

Palynology: its position in the field of forensic science

Here we examine the current state of palynology in the field of forensic science. Forensic palynology is discussed with reference to other forensic disciplines to help understand what is required for its progress. Emerging developments are also discussed. Palynomorphs potentially deliver excellent trace evidence, fulfilling the requirements relating to the transfer, persistence, and detection of such evidence. Palynological evidence can provide very powerful investigative and associative evidence. Despite this, the application of palynology to forensic science has had mixed success. There are many anecdotal stories where pollen evidence has had spectacular successes. But it is extremely underutilized in most countries because it is labor-intensive and requires considerable expertise and experience, there is a lack of control over sample collection and inadequate resourcing and funding, and its crime-solving power is not well known. Palynology has been applied to forensic problems in an unstructured way, resulting in a lack of formalized discussion of the underlying principles. As there is renewed questioning of the acceptability of most evidence types in the current legal environment, there is a need for the establishment of palynological evidence through validation-type studies and experimentation, and the implementation of independent proficiency testing.     

Fatty Acid Profiles for Differentiating Growth Medium Formulations Used to Culture Bacillus cereus T‐strain Spores

Microbial biomarkers that indicate aspects of an organism's growth conditions are important targets of forensic research. In this study, we examined fatty acid composition as a signature for the types of complex nutrients in the culturing medium. Bacillus cereus T‐strain spores were grown in medium formulations supplemented with one of the following: peptone (meat protein), tryptone (casein protein), soy protein, and brain–heart infusion. Cellular biomass was profiled with fatty acid methyl ester (FAME) analysis. Results showed peptone cultures produced spores enriched in straight‐chained lipids. Tryptone cultures produced spores enriched in branched‐odd lipids when compared with peptone, soy, and brain–heart formulations. The observed FAME variation was used to construct a set of discriminant functions that could help identify the nutrients in a culturing recipe for an unknown spore sample. Blinded classification tests were most successful for spores grown on media containing peptone and tryptone, showing 88% and 100% correct identification, respectively.     

Bioterrorism: processing contaminated evidence, the effects of formaldehyde gas on the recovery of latent fingermarks

In the present age of heightened emphasis on counter terrorism, law enforcement and forensic science are constantly evolving and adapting to the motivations and capabilities of terrorist groups and individuals. The use of biological agents on a population, such as anthrax spores, presents unique challenges to the forensic investigator, and the processing of contaminated evidence. In this research, a number of porous and nonporous items were contaminated with viable anthrax spores and marked with latent fingermarks. The test samples were then subjected to a standard formulation of formaldehyde gas. Latent fingermarks were then recovered post decontamination using a range of methods. Standard fumigation, while effective at destroying viable spores, contributed to the degradation of amino acids leading to loss of ridge detail. A new protocol for formaldehyde gas decontamination was developed which allows for the destruction of viable spores and the successful recovery of latent marks, all within a rapid response time of less than 1 h.     

Effect of Sterilants on Amplification and Detection of Target DNA from Bacillus cereus Spores

To conceal criminal activity of a bioterrorist or agroterrorist, the site of pathogen generation is often treated with sterilants to kill the organisms and remove evidence. As dead organisms cannot be analyzed by culture, this study examined whether DNA from sterilant‐treated Bacillus cereus spores was viable for amplification. The spores were exposed to five common sterilants: bleach, Sterilox®, oxidizer foam (L‐Gel), a peroxyacid (Actril®), and formaldehyde vapor. The spores were inoculated on typical surfaces found in offices and laboratories to test for environmental effects. It was found that the surface influenced the efficiency of recovery of the organisms. The DNA isolated from the recovered spores was successfully detected using RT‐qPCR for all treatments except for formaldehyde, by amplifying the phosphatidylinositol phospholipase C and sphingomyelinase genes. The results demonstrated that evidence from sites treated with sterilants can still provide information on the uncultured organism, using DNA amplification.