Abundance Of Protein Species Research Articles

Functional venomics of the Big-4 snakes of Pakistan

In South Asia, the “Big-4” venomous snakes Naja naja, Bungarus caeruleus, Daboia russelii, and Echis carinatus are so-called because they are the most medically important snakes in the region. Antivenom is the only effective treatment option for snakebite envenoming but antivenom is not produced domestically in Pakistan making the country reliant on polyvalent products imported from India and Saudi Arabia. The present study investigated the toxin composition and activity of the venoms of Pakistani specimens by means of proteomic and physio/pharmacological experiments. To evaluate the composition of venoms, 1D/2D-PAGE of crude venoms and RP-HPLC followed by SDS-PAGE were performed. Enzymatic, hemolytic, coagulant and platelet aggregating activities of crude venoms were assayed and were concordant with expectations based on the abundance of protein species in each. Neutralization assays were performed using Bharat polyvalent antivenom (BPAV), a product raised against venoms from Big-4 specimens from southern India. BPAV exhibited cross-reactivity against the Pakistani venoms, however, neutralization of clinically relevant activities was variable and rarely complete. Cumulatively, the presented data not only highlight geographical variations present in the venoms of the Big-4 snakes of South Asia, but also demonstrate the neutralization potential of Indian polyvalent against the venom of Pakistani specimens. Given the partial neutralization observed, it is clear that whilst BPAV is a life-saving product in Pakistan, in future it is hoped that a region-specific product might be manufactured domestically, using venoms of local snakes in the immunising mixture.

Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones.

Rubber elongation factor (REF) and small rubber particle protein (SRPP) are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF138,175,258 and SRPP117,204,243, were characterized from Hevea brasiliensis Reyan (RY) 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE), each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF175 or REF258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

Physiology and proteomics research on the leaves of ancient Platycladus orientalis (L.) during winter

Ancient trees have an important value in humanities and history, and also have an important scientific value in the investigation of the decline and senescence mechanisms. Thus, we conducted an environmental stress study using ancient trees. To evaluate age-dependent changes in physiology and the leaf proteome, we assessed the low-temperature stress responses of 20±5-, 500±100- and 1200±200-year-old Platycladus orientalis (L.) samples obtained outdoors during winter. Several physiological parameters were evaluated. Leaf proteomes were obtained using two-dimensional electrophoresis gels, and 77 protein spots were identified successfully using MALDI TOF/TOF MS/MS. The majority of the identified protein species were classified into functional categories including defense/stress-related, energy and carbohydrate metabolism, photosynthesis, and hormone-related functions. A general reduction in the abundance of protein species was observed as the age of the studied trees increased; reduction in photosynthesis and defense/stress-related categories were particularly apparent in the leaves of ancient trees. However, the number of protein species with functions in energy and carbohydrate metabolism increased with age. An increase in the abundance of lipid metabolism and hormone-related protein species was a primary characteristic of the leaves of ancient trees under low-temperature stress during winter. These results improve our understanding of the biochemical mechanisms of stress responses in ancient trees. Biological significanceLow temperature is the most common meteorological challenge in the study area. For evergreen plants, low-temperature stress has a great impact on the leaves of ancient P. orientalis. Thus, we conducted an environmental stress study using ancient trees. Recently, various studies were carried out in ancient trees. However, no information is available on the molecular mechanisms of defense to low-temperature stress in ancient trees. Therefore, this original study comprises the following differential proteomic analysis of ancient P. orientalis: (1) age-dependent changes in the physiology and leaf proteome are evaluated under low-temperature stress to (2) understand the differences in metabolic responses between ancient and adult trees under low-temperature stress during winter. This analysis will provide an understanding of the complex physiological changes that occur in ancient trees. The results suggest that certain identified proteins can be used as markers of low-temperature stress in ancient P. orientalis.

Proteomic and biochemical analysis of maize anthers after cold pretreatment and induction of androgenesis reveals an important role of anti-oxidative enzymes

In stress conditions, microspores and young pollen grains can be switched from their normal pollen development toward an embryogenic pathway via a process called androgenesis. Androgenic embryos can produce completely homozygous, haploid or double-haploid plants. This study aimed to investigate changes in the abundance of protein species during cold pretreatment and subsequent cultivation of maize anthers on induction media using gel-based proteomics. Proteins upregulated on the third day of anther induction were identified and discussed here. Simultaneous microscopic observations revealed that the first division occurred in microspores within this period. Using 2-D electrophoresis combined with MALDI TOF/TOF MS/MS analysis 19 unique proteins were identified and classified into 8 functional groups. Proteins closely associated with metabolism, protein synthesis and cell structure were the most abundant ones. Importantly, ascorbate peroxidase, an enzyme decomposing hydrogen peroxide, was also upregulated. Isozyme analysis of peroxidases validated the proteomic data and showed increased peroxidase activities during androgenic induction. Further, the isozyme pattern of SOD revealed increased activity of the MnSOD, which could provide hydrogen peroxide as a substrate for in vivo peroxidase reactions (including ascorbate peroxidase). Together, these data reveal the role of enzymes controlling oxidative stress during induction of maize androgenesis.

Computational Mass Spectrometry–Based Proteomics

Proteomics is defined as the system-widecharacterization of all the proteins in anorganism in terms of their sequence,localization, abundance, post-translationalmodifications, and biomolecular interac-tions. Modern proteomic investigationsare increasingly quantitative and compre-hensive [1]. Examples include the relativequantification of over 4,000 proteins inhaploid and diploid yeast, which identifiedthe pheromone signaling pathway asenriched in differential abundance [2];determination of site- and time-specificdynamics of more than 6,000 phosphory-lation sites of HeLa cells stimulated withepidermal growth factor [3]; and charac-terization of 232 multiprotein complexesin Saccharomyces cerevisiae, which proposednew cellular roles for 344 proteins [4].Such investigations are now successfullyutilized in functional biology [5,6], geno-mics [7,8], and biomedical research [9].Challenges of proteomic studies stemfrom the complexity of the proteome andto its broad dynamic range. For example,the human genome contains around20,000 protein coding genes. Their trans-lation, combined with splicing or proteol-ysis, yields an estimated 50,000–500,000proteins, and over 10 million differentprotein forms can be derived by somaticDNA rearrangements and post-transla-tional modifications [10]. The abundanceof protein species in human plasma spansmore than 10 orders of magnitude [11].Unlike oligonucleotides, proteins cannotbe amplified, and therefore the objectivesof proteomics are achieved by sensitiveand scalable technologies identifying andquantifying proteins [12]. The overallmass spectrometry–based proteomic work-flow is summarized in Figure 1.

Comparative proteomic analysis of NaCl stress-responsive proteins in Arabidopsis roots

NaCl stress is a major abiotic stress limiting the productivity and the geographical distribution of many plant species. Roots are the primary site of salinity perception. To understand better NaCl stress responses in Arabidopsis roots, a comparative proteomic analysis of roots that had been exposed to 150 mM NaCl for either 6 h or 48 h was conducted. Changes in the abundance of protein species within roots were examined using two-dimensional electrophoresis. Among the >1000 protein spots reproducibly detected on each gel, the abundance of 112 protein spots decreased and 103 increased, at one or both time points, in response to NaCl treatment. Through liquid-chromatography-tandem mass spectrometry, identity was assigned to 86 of the differentially abundant spots. The proteins identified included many previously characterized stress-responsive proteins and others related to processes including scavenging for reactive oxygen species; signal transduction; translation, cell wall biosynthesis, protein translation, processing and degradation; and metabolism of energy, amino acids, and hormones. At the resolution of individual genes and proteins, poor statistical correlation (6 h, r= -0.13; 48 h, r=0.11) of these protein expression data with previous microarray results was detected, supporting the concept that post-transcriptional regulation plays an important role in stress-responsive gene expression, and highlighting the need for combined transcriptomic and proteomic analyses.