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Evaluation of extraction methods for the identification of proteins from date palm (Phoenix dactylifera L.) seed and flesh

Lee HX, Ahmad F, Saad B, Ismail MN

Prep Biochem Biotechnol, 2017 Nov 26;47(10):998-1007.
PMID: 28857669 DOI: 10.1080/10826068.2017.1365250

Date fruits are well known to be very nutritious. Nevertheless, the protein contents of the fruit, particularly the seed and flesh, are still understudied, largely due to their difficult physical characteristics. This study was conducted to compare three different protein extraction methods which were the trichloroacetic acid (TCA)-acetone (TCA-A), phenol (Phe), and TCA-acetone-phenol (TCA-A-Phe), and to perform proteomic analysis on date palm seed and flesh. Phe extraction method showed the highest protein yields for both seed (8.26 mg/g) and flesh (1.57 mg/g). Through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Phe, and TCA-A-Phe extraction methods were shown to be efficient in removing interfering compounds and gave well-resolved bands over a wide range of molecular weights. Following liquid chromatography-tandem mass spectrometry analysis, about 50-64% of extracted proteins were identified with known functions including those involved in glycolysis, Krebs cycle, defense, and storage. Phe protein extraction method was proven to be the optimal method for date flesh and seed.

Matched MeSH terms: Trichloroacetic Acid/chemistry
Optimization method for proteomic analysis of the larva and adult tissues of plutella xylostella (l.) (lepidoptera: plutellidae)

Maizom Hassan, NorazilaYusoff, Wan Mohd Aizat, Idris Abd Ghani, Nurul Wahida Othman

Sains Malaysiana, 2018;47:2975-2983.

Plutella xylostella (L.) (Lepidoptera: Plutellidae), the major insect pest of cruciferous crops worldwide shows significant
resistance to almost all classes of insecticides. In order to effectively prevent and manage the insecticidal resistance,
it is crucial to understand the physiological adaptation of insects against insecticides. Identification of insect protein
that interacting with insecticides and characterization of their modification in resistant strains can be done by using
differential proteomics approach. This study focuses on optimizing a sensitive and rapid method for the extraction of
high quality protein of both larva and adult tissues of P. xylostella to be used in two-dimensional gel electrophoresis.
Five extraction methods were evaluated for protein concentration, yields and resolving patterns of one-dimensional
and two-dimensional electrophoresis. The results showed that trichloroacetic acid/acetone extraction methods with
two different concentrations of 2-mercaptoethanol produced the highest protein concentration and yield for both adult
and larva tissues, respectively. Meanwhile, trichloroacetic acid/acetone with dithiothreitol extraction method gave
better separation of spots and intensity for both larva and adult tissues compared to other methods tested. As such, we
concluded that trichloroacetic acid/acetone with dithiothreitol successfully yielded high total protein concentration and
good separation of two-dimensional electrophoresis gel spots in both adult and larva P. xylostella.

Matched MeSH terms: Trichloroacetic Acid
Precipitation of Hevea brasiliensis latex proteins with trichloroacetic acid and phosphotungstic acid in preparation for the Lowry protein assay

Yeang HY, Yusof F, Abdullah L

Anal Biochem, 1995 Mar 20;226(1):35-43.
PMID: 7785777

Many proteins derived from the latex of Hevea brasiliensis that remain soluble in trichloroacetic acid (TCA) can be precipitated by phosphotungstic acid (PTA). A combination of 5% TCA and 0.2% PTA precipitates a wide range of proteins effectively even when they are present in low concentrations (below 1 microgram ml-1). In addition to its protein purification function, acid precipitation also increases the sensitivity of the subsequent protein assay by allowing the test sample to be concentrated. Another advantage of protein precipitation by TCA and PTA is that very small amounts of protein (of the order of 10 micrograms) can be repeatably recovered without the use of precipitate-bulking agents such as sodium deoxycholate. This general procedure of protein purification and concentration is simple and rapid, but the use of PTA may not be fully compatible with the Bradford protein assay. A modified Lowry microassay is described which enables about 3 micrograms ml-1 to be quantitated at the photometric absorbance of 0.05. When used in conjunction with protein concentration by precipitating with TCA/PTA, approximately 0.4 microgram ml-1 protein present in 6 ml of solution can be assayed.

Matched MeSH terms: Trichloroacetic Acid
Optimization of Protein Extraction and Two-Dimensional Electrophoresis Protocols for Oil Palm Leaf

Daim LD, Ooi TE, Yusof HM, Majid NA, Karsani SA

Protein J, 2015 Aug;34(4):304-12.
PMID: 26263918 DOI: 10.1007/s10930-015-9626-x

Oil palm (Elaeis guineensis) is an important economic crop cultivated for its nutritional palm oil. A significant amount of effort has been undertaken to understand oil palm growth and physiology at the molecular level, particularly in genomics and transcriptomics. Recently, proteomics studies have begun to garner interest. However, this effort is impeded by technical challenges. Plant sample preparation for proteomics analysis is plagued with technical challenges due to the presence of polysaccharides, secondary metabolites and other interfering compounds. Although protein extraction methods for plant tissues exist, none work universally on all sample types. Therefore, this study aims to compare and optimize different protein extraction protocols for use with two-dimensional gel electrophoresis of young and mature leaves from the oil palm. Four protein extraction methods were evaluated: phenol-guanidine isothiocyanate, trichloroacetic acid-acetone precipitation, sucrose and trichloroacetic acid-acetone-phenol. Of these four protocols, the trichloroacetic acid-acetone-phenol method was found to give the highest resolution and most reproducible gel. The results from this study can be used in sample preparations of oil palm tissue for proteomics work.

Matched MeSH terms: Trichloroacetic Acid
Fulltext Penile warts: an update on their evaluation and management

Leung AK, Barankin B, Leong KF, Hon KL

Drugs Context, 2018;7:212563.
PMID: 30622585 DOI: 10.7573/dic.212563

Background: Penile warts are the most common sexually transmitted disease in males. Clinicians should be familiar with the proper evaluation and management of this common condition.
Objective: To provide an update on the current understanding, evaluation, and management of penile warts.
Methods: A PubMed search was completed in Clinical Queries using the key terms 'penile warts' and 'genital warts'. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews.
Results: Penile warts are caused by human papillomavirus (HPV), notably HPV-6 and HPV-11. Penile warts typically present as asymptomatic papules or plaques. Lesions may be filiform, exophytic, papillomatous, verrucous, hyperkeratotic, cerebriform, fungating, or cauliflower-like. Approximately one-third of penile warts regress without treatment and the average duration prior to resolution is approximately 9 months. Active treatment is preferable to watchful observation to speed up clearance of the lesions and to assuage fears of transmission and autoinoculation. Patient-administered therapies include podofilox (0.5%) solution or gel, imiquimod 3.75 or 5% cream, and sinecatechins (polypheron E) 15% ointment. Clinician-administered therapies include podophyllin, cryotherapy, bichloroacetic or trichloroacetic acid, oral cimetidine, surgical excision, electrocautery, and carbon dioxide laser therapy. Patients who do not respond to first-line treatments may respond to other therapies or a combination of treatment modalities. Second-line therapies include topical/intralesional/intravenous cidofovir, topical 5-fluorouracil, and topical ingenol mebutate.
Conclusion: No single treatment has been shown to be consistently superior to other treatment modalities. The choice of the treatment method should depend on the physician's comfort level with the various treatment options, the patient's preference and tolerability of treatment, and the number and severity of lesions. The comparative efficacy, ease of administration, adverse effects, cost, and availability of the treatment modality should also be taken into consideration.

Matched MeSH terms: Trichloroacetic Acid