Unknown Sequence Research Articles

ZiMM: A deep learning model for long term and blurry relapses with non-clinical claims data.

This paper considers the problems of modeling and predicting a long-term and "blurry" relapse that occurs after a medical act, such as a surgery. We do not consider a short-term complication related to the act itself, but a long-term relapse that clinicians cannot explain easily, since it depends on unknown sets or sequences of past events that occurred before the act. The relapse is observed only indirectly, in a "blurry" fashion, through longitudinal prescriptions of drugs over a long period of time after the medical act. We introduce a new model, called ZiMM (Zero-inflated Mixture of Multinomial distributions) in order to capture long-term and blurry relapses. On top of it, we build an end-to-end deep-learning architecture called ZiMM Encoder-Decoder (ZiMM ED) that can learn from the complex, irregular, highly heterogeneous and sparse patterns of health events that are observed through a claims-only database. ZiMM ED is applied on a "non-clinical" claims database, that contains only timestamped reimbursement codes for drug purchases, medical procedures and hospital diagnoses, the only available clinical feature being the age of the patient. This setting is more challenging than a setting where bedside clinical signals are available. Our motivation for using such a non-clinical claims database is its exhaustivity population-wise, compared to clinical electronic health records coming from a single or a small set of hospitals. Indeed, we consider a dataset containing the claims of almost all French citizens who had surgery for prostatic problems, with a history between 1.5 and 5 years. We consider a long-term (18 months) relapse (urination problems still occur despite surgery), which is blurry since it is observed only through the reimbursement of a specific set of drugs for urination problems. Our experiments show that ZiMM ED improves several baselines, including non-deep learning and deep-learning approaches, and that it allows working on such a dataset with minimal preprocessing work.

Bleaching correction for DNA measurements in highly diluted solutions using confocal microscopy.

Determining the concentration of nucleic acids in biological samples precisely and reliably still is a challenge. In particular when only very small sample quantities are available for analysis, the established fluorescence-based methods give insufficient results. Photobleaching is seen as the main reason for this. In this paper we present a method to correct for the photobleaching effect. Using confocal microscopy with single molecule sensitivity, we derived calibration curves from DNA solutions with defined fragment length. We analyzed dilution series over a wide range of concentrations (1 pg/μl-1000 pg/μl) and measured their specific diffusion coefficients employing fluorescence correlation spectroscopy. Using this information, we corrected the measured fluorescence intensity of the calibration solutions for photobleaching effects. We evaluated our method by analyzing a series of DNA mixtures of varying composition. For fragments smaller than 1000 bp, our method allows to determine sample concentrations with high precision in very small sample quantities (< 2 μl with concentrations < 20 pg/μl). Once the technical parameters are determined and remain stable in an established process, our improved calibration method will make measuring molecular biological samples of unknown sequence composition more efficient, accurate and sample-saving than previous methods.

SLFinder, a pipeline for the novel identification of splice-leader sequences: a\xa0good enough solution for a complex problem

BackgroundSpliced Leader trans-splicing is an important mechanism for the maturation of mRNAs in several lineages of eukaryotes, including several groups of parasites of great medical and economic importance. Nevertheless, its study across the tree of life is severely hindered by the problem of identifying the SL sequences that are being trans-spliced.ResultsIn this paper we present SLFinder, a four-step pipeline meant to identify de novo candidate SL sequences making very few assumptions regarding the SL sequence properties. The pipeline takes transcriptomic de novo assemblies and a reference genome as input and allows the user intervention on several points to account for unexpected features of the dataset. The strategy and its implementation were tested on real RNAseq data from species with and without SL Trans-Splicing.ConclusionsSLFinder is capable to identify SL candidates with good precision in a reasonable amount of time. It is especially suitable for species with unknown SL sequences, generating candidate sequences for further refining and experimental validation.

Characterization of the First W-Specific Protein-Coding Gene for Sex Identification in Helicoverpa armigera.

Helicoverpa armigera is a globally-important crop pest with a WZ (female)/ZZ (male) sex chromosome system. The absence of discernible sexual dimorphism in its egg and larval stages makes it impossible to address any sex-related theoretical and applied questions before pupation unless a W-specific sequence marker is available for sex diagnosis. To this end, we used one pair of morphologically pre-sexed pupae to PCR-screen 17 non-transposon transcripts selected from 4855 W-linked candidate reads identified by mapping a publicly available egg transcriptome of both sexes to the male genome of this species and detected the read SRR1015458.67499 only in the female pupa. Subsequent PCR screenings of this read and the previously reported female-specific RAPD (random amplified polymorphic DNA) marker AF18 with ten more pairs of pre-sexed pupae and different annealing positions and/or temperatures as well as its co-occurrence with the female-specific transcript splicing isoforms of doublesex gene of H. armigera (Hadsx) and amplification and sequencing of their 5′ unknown flanking sequences in three additional pairs of pre-sexed pupae verified that SRR1015458.67499 is a single copy protein-coding gene unique to W chromosome (named GUW1) while AF18 is a multicopy MITE transposon located on various chromosomes. Test application of GUW1 as a marker to sex 30 neonates of H. armigera yielded a female/male ratio of 1.14: 1.00. Both GUW1 and Hadsx splicing isoforms assays revealed that the H. armigera embryo cell line QB-Ha-E-1 is a male cell line. Taken together, GUW1 is not only a reliable DNA marker for sexing all stages of H. armigera and its cell lines, but also represents the first W-specific protein-coding gene in lepidopterans.

Gene Similarity Networks Unveil a Potential Novel Unicellular Group Closely Related to Animals from the Tara Oceans Expedition.

The Holozoa clade comprises animals and several unicellular lineages (choanoflagellates, filastereans, and teretosporeans). Understanding their full diversity is essential to address the origins of animals and other evolutionary questions. However, they are poorly known. To provide more insights into the real diversity of holozoans and check for undiscovered diversity, we here analyzed 18S rDNA metabarcoding data from the global Tara Oceans expedition. To overcome the low phylogenetic information contained in the metabarcoding data set (composed of sequences from the short V9 region of the gene), we used similarity networks by combining two data sets: unknown environmental sequences from Tara Oceans and known reference sequences from GenBank. We then calculated network metrics to compare environmental sequences with reference sequences. These metrics reflected the divergence between both types of sequences and provided an effective way to search for evolutionary relevant diversity, further validated by phylogenetic placements. Our results showed that the percentage of unicellular holozoan diversity remains hidden. We found novelties in several lineages, especially in Acanthoecida choanoflagellates. We also identified a potential new holozoan group that could not be assigned to any of the described extant clades. Data on geographical distribution showed that, although ubiquitous, each unicellular holozoan lineage exhibits a different distribution pattern. We also identified a positive association between new animal hosts and the ichthyosporean symbiont Creolimax fragrantissima, as well as for other holozoans previously reported as free-living. Overall, our analyses provide a fresh perspective into the diversity and ecology of unicellular holozoans, highlighting the amount of undescribed diversity.

On Data Increasing in Phase Retrieval via Quadratic Inversion: Flattening Manifold and Local Minima

In this article, we address the question of traps in phase retrieval via quadratic inversion. First, we clarify the genesis of local minima from a geometrical perspective by showing how the shape of the manifold of data and the position of the data point are related to the presence of local minima in the objective functional. Later, we recall a mathematical condition for the lack of traps. Afterward, we illustrate how the ratio between the dimension of data space $M$ and the number of real unknowns $N_{r}$ impacts on the manifold of data and, consequently, on the presence of local minima. In particular, we show that if the dimension of data space is high enough, the manifold of data is sufficiently large and no traps appear in the functional. In the last part of this article, with reference to a particular unknown sequence, we establish the minimum value of the ratio ${M}/{N_{r}}$ such that no traps should appear in the functional. In this condition, phase retrieval via quadratic inversion exhibits a global convergence behavior, consequently, the actual solution of the problem can be reached regardless of the initial guess which can be chosen completely at random.

LuluDB-The Database Created Based on Small RNA, Transcriptome, and Degradome Sequencing Shows the Wide Landscape of Non-coding and Coding RNA in Yellow Lupine (Lupinus luteus L.) Flowers and Pods.

Yellow lupine (Lupinus luteus L.) belongs to a legume family that benefits from symbiosis with nitrogen-fixing bacteria. Its seeds are rich in protein, which makes it a valuable food source for animals and humans. Yellow lupine is also the model plant for basic research on nodulation or abscission of organs. Nevertheless, the knowledge about the molecular regulatory mechanisms of its generative development is still incomplete. The RNA-Seq technique is becoming more prominent in high-throughput identification and expression profiling of both coding and non-coding RNA sequences. However, the huge amount of data generated with this method may discourage other scientific groups from making full use of them. To overcome this inconvenience, we have created a database containing analysis-ready information about non-coding and coding L. luteus RNA sequences (LuluDB). LuluDB was created on the basis of RNA-Seq analysis of small RNA, transcriptome, and degradome libraries obtained from yellow lupine cv. Taper flowers, pod walls, and seeds in various stages of development, flower pedicels, and pods undergoing abscission or maintained on the plant. It contains sequences of miRNAs and phased siRNAs identified in L. luteus, information about their expression in individual samples, and their target sequences. LuluDB also contains identified lncRNAs and protein-coding RNA sequences with their organ expression and annotations to widely used databases like GO, KEGG, NCBI, Rfam, Pfam, etc. The database also provides sequence homology search by BLAST using, e.g., an unknown sequence as a query. To present the full capabilities offered by our database, we performed a case study concerning transcripts annotated as DCL 1–4 (DICER LIKE 1–4) homologs involved in small non-coding RNA biogenesis and identified miRNAs that most likely regulate DCL1 and DCL2 expression in yellow lupine. LuluDB is available at http://luluseqdb.umk.pl/basic/web/index.php.

Genome sequences of two Salmonella enterica strains (MEZSAL74 and MEZSAL81) harbouring multiple antimicrobial resistance genes isolated from livestock in South Africa

ObjectivesAntimicrobial-resistant livestock-associated Salmonella enterica infections pose a significant public-health threat worldwide. Here we report for the first time the draft genome sequences of two multidrug-resistant livestock-associated S. enterica strains isolated from a chicken and a cow in South Africa. MethodsGenomic DNA of S. enterica strains MEZSAL74 and MEZSAL81 was sequenced using an Illumina MiSeq platform. The generated reads were trimmed and de novo assembled. The assembled contigs were analysed for antimicrobial resistance genes, chromosomal mutations and extrachromosomal plasmids. Multilocus sequence typing (MLST) was also performed. In order to compare isolates MEZSAL74 and MEZSAL81 with other previously sequenced S. enterica isolates, raw read sequences were downloaded and all sequence files were treated identically to generate a bootstrapped maximum likelihood phylogenetic tree. ResultsExtrachromosomal plasmids and genetic determinants of antimicrobial resistance were detected in both sequenced bacterial isolates to aminoglycosides and fluoroquinolones. By MLST, strain MEZSAL74 belonged to an unknown sequence type (ST) and strain MEZSAL81 belonged to ST33. ConclusionThe genome sequences of strains MEZSAL74 and MEZSAL81 reported here will serve as a reference for molecular epidemiological studies of antimicrobial-resistant livestock-associated S. enterica in Africa.

Creating New β-Globin-Expressing Lentiviral Vectors by High-Resolution Mapping of Locus Control Region Enhancer Sequences

Hematopoietic stem cell gene therapy is a promising approach for treating disorders of the hematopoietic system. Identifying combinations of cis-regulatory elements that do not impede packaging or transduction efficiency when included in lentiviral vectors has proven challenging. In this study, we deploy LV-MPRA (lentiviral vector-based, massively parallel reporter assay), an approach that simultaneously analyzes thousands of synthetic DNA fragments in parallel to identify sequence-intrinsic and lineage-specific enhancer function at near-base-pair resolution. We demonstrate the power of LV-MPRA in elucidating the boundaries of previously unknown intrinsic enhancer sequences of the human β-globin locus control region. Our approach facilitated the rapid assembly of novel therapeutic βAS3-globin lentiviral vectors harboring strong lineage-specific recombinant control elements capable of correcting a mouse model of sickle cell disease. LV-MPRA can be used to map any genomic locus for enhancer activity and facilitates the rapid development of therapeutic vectors for treating disorders of the hematopoietic system or other specific tissues and cell types.

The completed macronuclear genome of a model ciliate Tetrahymena thermophila and its application in genome scrambling and copy number analyses

The ciliate Tetrahymena thermophila has been a powerful model system for molecular and cellular biology. However, some investigations have been limited due to the incomplete closure and sequencing of the macronuclear genome assembly, which for many years has been stalled at 1,158 scaffolds, with large sections of unknown sequences (available in Tetrahymena Genome Database, TGD, http://ciliate.org/ ). Here we completed the first chromosome-level Tetrahymena macronuclear genome assembly, with approximately 300× long Single Molecule, Real-Time reads of the wild-type SB210 cells-the reference strain for the initial macronuclear genome sequencing project. All 181 chromosomes were capped with two telomeres and gaps were entirely closed. The completed genome shows significant improvements over the current assembly (TGD 2014) in both chromosome structure and sequence integrity. The majority of previously identified gene models shown in TGD were retained, with the addition of 36 new genes and 883 genes with modified gene models. The new genome and annotation were incorporated into TGD. This new genome allows for pursuit in some underexplored areas that were far more challenging previously; two of them, genome scrambling and chromosomal copy number, were investigated in this study. We expect that the completed macronuclear genome will facilitate many studies in Tetrahymena biology, as well as multiple lines of research in other eukaryotes.

Characterization of Viral Communities Carried by Male and Female Aedes Mosquitos Collected in Houston

Mosquitos are known vectors of many serious viral diseases, but little is known about the complete collection of viral strains that they might carry. This is because we have historically relied on culturing techniques to study microbial diversity, but the genomic era has shown us that there is much more out there than we initially suspected. In this work, we present a genomic approach to characterizing the viral populations carried by different species of mosquitos found in Houston. Specifically, we are using metagenomics – that is, sequencing the entire genetic material in a sample, followed by analyses by computational tools to identify each sequence obtained from the sample. We collected mosquitos from various locations in Houston and separated them by species and sex using morphological and genetic markers. Total DNA and RNA were purified from pooled samples in order to characterize both DNA and RNA viruses. RNA samples were converted to cDNA to facilitate sequencing and the combined DNA/cDNA libraries were sequenced using 454 technology. We used a modified BLAST workflow developed in‐house to analyze the sequences. Our first analysis shows viral sequences obtained for samples of male and female Aedes aegypti. While thousands of unknown sequences were obtained, our results show that we are also able to detect both DNA and RNA viral sequences in our samples. A total of 51 different species of viruses were identified in the female sample, and 40 different species were found in the male sample. Those of interest include West Nile and Dengue. Interestingly, the female sample carried more RNA viruses than the male sample, although further work will reveal if this finding is significant or an experimental artifact. We plan on further analyzing the sequence libraries obtained, with particular focus on the unknown sequences, many of which may be viral. We are also working on building new libraries from new samples of mosquitos, including other genera typically found in Houston, such as Culex. These analyses will help us better understand the viral collections carried by different mosquitos in our city.Support or Funding InformationU.S. DOE Hispanic‐Serving Institutions STEM Articulation Grant P031C110128, the University of St. Thomas Cullen‐Smith Endowed Chair in Biology, and the University of St. Thomas Committee for Student Research.

A new numerical approach for DNA representation using modified Gabor wavelet transform for the identification of protein coding regions

The fundamental step in genomic signal processing applications is to assign mathematical descriptor to nucleotides {A, T, G, C} of DNA molecule for discrete representation. The discrete representation should replicate biological information of gene when analyzed with digital signal processing tools. In this aspect, a novel binary representation of DNA sequence by combining structural and chemical information of original DNA sequence has been proposed for the identification of protein coding regions of eukaryotes. The identification model comprises two stages, mainly, numerical encoding in first stage, and analysis of biological behavior through digital signal processing algorithms in second stage. In the first stage, a new numerical encoding method based on Walsh codes of order-4 is proposed to obtain 1-D binary discrete sequence. In the second stage, the modified Gabor wavelet transform (MGWT) is employed on the discretized DNA sequence for spectrum analysis. The optimal gene numerical encoding and multiresolution approach of MGWT has readily identified the structures of coding regions of unknown gene sequences. The proposed model is validated by analyzing prediction efficiency in terms of statistical metrics such as sensitivity, specificity, accuracy on both sequence and data base level. Furthermore, the results are compared by plotting receiver operating curves (ROC) for all classification thresholds for the state-of-art encoding methods. Area under curve (AUC) value of 0.86 at sequence level and 0.84 at database level is achieved. Performance metrics indicate that the proposed encoding method exhibits relatively better performance than other numerical encoding methods.

Hands-On Electrospray Ionization Mass Spectrometry for Undergraduate Biochemistry Students: Peptide Identification by Ladder Sequencing

Mass spectrometers are ever-increasingly powerful, user-friendly, and affordable. Thus, the addition of mass spectrometry experiments into the undergraduate laboratory curriculum is now both feasible and an effective tool to introduce students to relevant instrumentation. Here an experiment demonstrating the use of a high-resolution electrospray ionization mass spectrometer (ESI-HRMS) for the identification of peptide sequences and the differentiation of isomeric peptides was developed and implemented in a biochemistry laboratory course for third-year chemistry major undergraduate students. This lab activity was a first introduction to mass spectrometry for undergraduate biochemistry students. As a prelab assignment, students were tasked to predict the mass-to-charge ratios and the fragmentation patterns for six given peptides using an online fragmentation prediction tool (Protein Prospector’s MS-Product tool). Students then analyzed two unknown peptides using ESI-HRMS. The theoretical and experimental results were compared to reveal the identity of the two unknown peptides. The student success rate of recognizing the unknown peptide sequences was 87.5%. This laboratory experiment provided students with hands-on experience using a research-grade ESI-HRMS instrument to solve a bioanalytical problem—specifically, the identification of the primary structure of a peptide of unknown sequence. Learning outcomes were evaluated for this experiment, which showed student understanding of peptide sequencing using mass spectrometry.

Pathogenic Effect of GDAP1 Gene Mutations in a Yeast Model.

The question of whether a newly identified sequence variant is truly a causative mutation is a central problem of modern clinical genetics. In the current era of massive sequencing, there is an urgent need to develop new tools for assessing the pathogenic effect of new sequence variants. In Charcot-Marie-Tooth disorders (CMT) with their extreme genetic heterogeneity and relatively homogenous clinical presentation, addressing the pathogenic effect of rare sequence variants within 80 CMT genes is extremely challenging. The presence of multiple rare sequence variants within a single CMT-affected patient makes selection for the strongest one, the truly causative mutation, a challenging issue. In the present study we propose a new yeast-based model to evaluate the pathogenic effect of rare sequence variants found within the one of the CMT-associated genes, GDAP1. In our approach, the wild-type and pathogenic variants of human GDAP1 gene were expressed in yeast. Then, a growth rate and mitochondrial morphology and function of GDAP1-expressing strains were studied. Also, the mutant GDAP1 proteins localization and functionality were assessed in yeast. We have shown, that GDAP1 was not only stably expressed but also functional in yeast cell, as it influenced morphology and function of mitochondria and altered the growth of a mutant yeast strain. What is more, the various GDAP1 pathogenic sequence variants caused the specific for them effect in the tests we performed. Thus, the proposed model is suitable for validating the pathogenic effect of known GDAP1 mutations and may be used for testing of unknown sequence variants found in CMT patients.

The phase transition for the existence of the maximum likelihood estimate in high-dimensional logistic regression

This paper rigorously establishes that the existence of the maximum likelihood estimate (MLE) in high-dimensional logistic regression models with Gaussian covariates undergoes a sharp “phase transition.” We introduce an explicit boundary curve $h_{\mathrm{MLE}}$, parameterized by two scalars measuring the overall magnitude of the unknown sequence of regression coefficients, with the following property: in the limit of large sample sizes $n$ and number of features $p$ proportioned in such a way that $p/n\rightarrow \kappa $, we show that if the problem is sufficiently high dimensional in the sense that $\kappa >h_{\mathrm{MLE}}$, then the MLE does not exist with probability one. Conversely, if $\kappa <h_{\mathrm{MLE}}$, the MLE asymptotically exists with probability one.

Tuning of Oxidation Potential of Ferrocene for Ratiometric Redox Labeling and Coding of Nucleotides and DNA.

Three sets of 7‐deazaadenine and cytosine nucleosides and nucleoside triphosphates bearing either unsubstituted ferrocene, octamethylferrocene and ferrocenecarboxamide linked through an alkyne tether to position 7 or 5, respectively, were designed and synthesized. The modified dNFcXTPs were good substrates for KOD XL DNA polymerase in primer extension and were used for enzymatic synthesis of redox‐labelled DNA probes. Square‐wave voltammetry showed that the octamethylferrocene oxidation potential was shifted to lower values, whilst the ferrocenecarboxamide was shifted to higher potentials, as compared to ferrocene. Tailed PEX products containing different ratios of Fc‐labelled A (dAFc) and FcPa‐labelled C (dCFcPa) were synthesized and hybridized with capture oligonucleotides immobilized on gold electrodes to study the electrochemistry of the redox‐labelled DNA. Clearly distinguishable, fully orthogonal and ratiometric peaks were observed for the dAFc and dCFcPa bases in DNA, demonstrating their potential for use in redox coding of nucleobases and for the direct electrochemical measurement of the relative ratio of nucleobases in an unknown sequence of DNA.

Antibacterial activity of the venom of the Ponerine ant Pachycondyla striata (Formicidae: Ponerinae)

Animal venom peptides have been reported as potential antimicrobial molecules for the development of novel antibiotics against resistant bacteria. Recent studies indicate that ant venoms is an important source of novel antimicrobial peptides. In the present study, the antimicrobial activity of the venom of the predatory ant Pachycondyla striata Smith, 1858, was evaluated against some pathogenic bacteria of medical importance. Growth inhibition tests revealed that the venom has broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria. Mass spectrometry analysis of the fractions with antimicrobial activity allowed the identification of venom allergen and venom allergen 5 as well as a peptide of unknown sequence. These three compounds exhibited antibacterial activity against the tested human pathogens.

An Approach to Enhance the Design of Protein Sequence Classifier Using Data Mining

Analysis of protein plays a major role in bio-informatics domain. Protein sequence classification is most vital in this analysis of protein. In this scenario, different researchers proposed various techniques to classify protein sequence which is reviewed here at first. Different features extraction procedure from the protein sequence is a common part of all proposed classification model. But selection and arrangement of features are the most challenging task for classifying unknown protein sequences into its known families with high accuracy and preferable computational time. Analysis of recent trend points that traditional database system fails to classify a large amount of biological data which is overcome by data mining approach. New classification model involving four phases has been proposed here for classifying the unknown sequences into its family, generating knowledge-based as well as data analysis procedure. Here a hybrid algorithm with the combination of Fuzzy ARTMAP and neural network based algorithm is used. Neighbourhood analysis is also done in the final stage. This proposed model has implemented and validated with 497 different test sequences. Finally, it is also compared with the previous model and produce high accuracy level with low computation time than previous.

A New Method of Gene Information Vectorization and its Application in Similarity Search

With the development of the Human Genome Project, more and more biological sequence data are generated, and the analysis and processing of these sequence data have promoted the development of bioinformatics. Sequence similarity analysis is the basis of bioinformatics, through which we can use the information of known sequences to study the structure, function and evolutionary relationship of unknown new sequences. This paper performs data compression and retrieval on the genome database based on the dbSNP information of DNA. According to the rule of determining a protein by three bases, the amino acid characters are determined, and the redundant information is removed by using the dbSNP information. It is the first time to propose the construction of a new compressed form of biological sequence structure, which can reflect the strong correlation between the SNP location information and SNP in each sample in the genome. Finally, this paper constructs a complete biological sequence approximate neighbor query system, which can not only greatly reduce the storage and computing overhead, but also improve the query efficiency under the condition of ensuring the retrieval accuracy. The accuracy and scalability of this method are verified by experiments on a large data set of gene database.

Sporopollenin: The Ground Discussion

Sporopollenin is an ubiquitous and extremely chemically inert biopolymer. The surface of sporopollenin is richly sculptured, ornamented and porous and is species specific. It is stable in organic and aqueous solvents. It is insoluble in common acids and in most organic solvents. Sporopollenins have very similar chemical structures and to be identical in structure to the synthetic carotenoid polymes. The sporopollenins derived from angiosperms, gymnosperms and ferns and lower plant spores have similar chemical structures and also they are similar to synthetic polymers. Sporopollenins are strongly osmophilic. Sporopollenins react with basic dyes suggesting the presence of weakly amnionic groups such as acidic-enolic compounds. Sporopollenin can be isolated from spores or pollen grain by treating with solvents or enzymes that remove intine and cytoplasm. Purified sporopollenin retains the similar shape, size, and surface features as in its spore or pollen grain and remains an empty shell i.e sporopollenin microcapsules. The different methods developed to isolate sporopollenin from L. clavatum proved its exceptional stability and chemical inertness. Wiermann et al has proved that, the sporopollein survived a wide range of enzymes. This may explain why it does not easily submit to bacterial decomposition or digestion. Its principle function is to protect against oxidation and desiccation. The study led by Maak proved that sporopollenin by Chlorella vulgaris was harmless and could be rubbed on skin with no irritation, swallowed without any danger or even injected in blood stream. The sporopollenin particles were found to cause an antigenic reation and bind to antibodies. The sporopollenin remains unchanged when heated up to 3000C or treated with concentrated acids and bases. Sporopollenin appears to undergo carbonization and coalification with haet. The sporopollenin decomposes by chemolyses and ozonolysis. An unknown enzymatic sequence linked to the clotting cascade has also been discovered that degrades sporopollenin in the blood, both in vitro and in vivo.