植物生物反应器生产药物蛋白的前景

转基因植物作为生物反应器生产重要的药用蛋白,如抗体、血液替代品和疫苗,为健康保健和科学研究提供充足的生物药物,满足人们日益增长的需要。本文综述了这一领域的研究进展以及商业化前景。     

乳酸克鲁维酵母表达外源蛋白研究进展

乳酸克鲁维酵母已成功地应用于多种异源蛋白的表达生产之中。与其他酵母相比，乳酸克鲁维酵母具有许多优点，如超强的分泌能力，良好的大规模发酵特性、食品安全的级别及整合表达能力等，其作为宿主系统表达药用蛋白也已显示出巨大的潜力。从不同的菌属、遗传工程和分子生物学技术（如启动子、表达载体）等方面简要综述了乳酸克鲁维酵母作为蛋白表达宿主系统的优势。     

Cloning of Fish Enzymes and Other Fish Protein Genes

ABSTRACT:?

Fish metabolism needs special enzymes that have maximum activity at very different conditions than their mammalian counterparts. Due to the differences in activity, these enzymes, especially cold-adapted proteases, could be used advantageously for the production of some foods. In addition to the enzymes, this review describes some other unique fish polypeptides such as antifreeze proteins, fluorescent proteins, antitumor peptides, antibiotics, and hormones, that have already been cloned and used in food processing, genetic engineering, medicine, and aquaculture. Recombinant DNA technology, which allows these biological molecules to be cloned and overexpressed in microorganisms is also described, highlighting innovative applications. The expected impact of cloning fish proteins in different fields of technology is discussed.     

Implications of climate change for agricultural productivity in the early twenty-first century

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO₂ rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.     

Botanicals authentication in food,food supplements and herbal medicinal products

Nowadays, there is a constant increase of health products (food supplements, medical devices and so on), in the market, despite the crisis that involves a lot of nations at the international level. The plants and their derivatives are present in high percentage in these products and moreover people usually have great trust in plants and in natural products in general. The above-mentioned products are available in the market in the form of tablets, pills, lozenges, syrups and other forms that supplement our diet (food or dietary supplements) or act with a therapeutic effect (herbal medicines). In Italy, about 50% of the sold products contain plants and/or plant extracts, better known as botanicals according to the European Food Safety Authority settlement. It is therefore understandable how the botanicals adulteration and/or the sophistication can heavily weigh on the quality of the finished products, not only from an economic point of view but also in guaranteeing the safety of consumers.     

Food insecurity: Prevalence,causes, and the potential of transgenic `Golden Rice'

This paper reviews a number of recent social science publications on the nature and causes of food insecurity in low and middle-income countries. The focus is on one specific element of food insecurity, vitamin A deficiency, which is widespread in developing countries and causes blindness and early death among millions of children. A new approach in the fight against vitamin A deficiency is `Golden Rice'. The paper explores the pros and cons of this recently developed transgenic rice variety, and tries to answer the question whether in this particular case, genetic modification technology provides a solution to food insecurity. It is concluded that Golden Rice is one of the options available, but not necessarily the most effective one.     

Marker-assisted selection: an approach for precision plant breeding in the twenty-first century

DNA markers have enormous potential to improve the efficiency and precision of conventional plant breeding via marker-assisted selection (MAS). The large number of quantitative trait loci (QTLs) mapping studies for diverse crops species have provided an abundance of DNA marker-trait associations. In this review, we present an overview of the advantages of MAS and its most widely used applications in plant breeding, providing examples from cereal crops. We also consider reasons why MAS has had only a small impact on plant breeding so far and suggest ways in which the potential of MAS can be realized. Finally, we discuss reasons why the greater adoption of MAS in the future is inevitable, although the extent of its use will depend on available resources, especially for orphan crops, and may be delayed in less-developed countries. Achieving a substantial impact on crop improvement by MAS represents the great challenge for agricultural scientists in the next few decades.     

Nanoliposomes and Their Applications in Food Nanotechnology

Food nanotechnology involves the utilization of nanocarrier systems to stabilize the bioactive materials against a range of environmental and chemical changes as well as to improve their bioavailability. Nanoliposome technology presents exciting opportunities for food technologists in areas such as encapsulation and controlled release of food materials, as well as the enhanced bioavailability, stability, and shelf-life of sensitive ingredients. Liposomes and nanoliposomes have been used in the food industry to deliver flavors and nutrients and, more recently, have been investigated for their ability to incorporate antimicrobials that could aid in the protection of food products against microbial contamination. In this paper, the main physicochemical properties of liposomes and nanoliposomes are described and some of the industrially applicable methods for their manufacture are reviewed. A summary of the application of nanoliposomes as carrier vehicles of nutrients, nutraceuticals, enzymes, food additives, and food antimicrobials is also presented.     

Trace Metals (Cd,Co, Cr,Cu, Hg,Ni, Pb,and Zn) in Food Supplements of Marine Origin

We determined the concentrations of Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn in dietary supplements of marine origin. Four supplement categories were studied; algae, coral, krill, and shark cartilage. A direct mercury analyzer was used for Hg determinations while acid digestions and ICP-AES were used for Cr analysis and ICP-MS for the other trace metals. Algae are the supplements showing the highest concentrations of Pb, Cr, and Ni with respective means of 1.6 mg Pb/kg dry weight (d.w.), 3.2 Cr mg/kg d.w., and 8.0 mg Ni/kg d.w. Krill supplements have the highest levels of Cd, Cu, and Zn with 0.65 mg Cd/kg d.w., 63 mg Cu/kg d.w., and 50 mg Zn/kg d.w., respectively. Shark cartilage supplements show the highest levels of Hg and Co with mean concentrations of 160 μg Hg/kg d.w. and 73 ± 51 μg Co/kg d.w., respectively. No samples in our study exceeded the provisional tolerable daily intakes set by Health Canada, the joint committee of the World Health Organization/Food and Agricultural Organization, or the U.S. Environmental Protection Agency. Nevertheless, Ni and Pb in algae and Hg in shark cartilage may end up contributing to a very significant portion of the allowable daily intake—leaving little room for normal intake through food consumption and other exposure pathways.     

N-Glycoprotein biosynthesis in plants: recent developments and future trends

N-glycosylation is a major modification of proteins in plant cells. This process starts in the endoplasmic reticulum by the co-translational transfer of a precursor oligosaccharide to specific asparagine residues of the nascent polypeptide chain. Processing of this oligosaccharide into high-mannose-type, paucimannosidic-type, hybrid-type or complex-type N-glycans occurs in the secretory pathway as the glycoprotein moves from the endoplasmic reticulum to its final destination. At the end of their maturation, some plant N-glycans have typical structures that differ from those found in their mammalian counterpart by the absence of sialic acid and the presence of (1,2)-xylose and (1,3)-fucose residues. Glycosidases and glycosyltransferases that respectively catalyse the stepwise trimming and addition of sugar residues are generally considered as working in a co-ordinated and highly ordered fashion to form mature N-glycans. On the basis of this assembly line concept, fast progress is currently made by using N-linked glycan structures as milestones of the intracellular transport of proteins along the plant secretory pathway. Further developments of this approach will need to more precisely define the topological distribution of glycosyltransferases within a plant Golgi stack. In contrast with their acknowledged role in the targeting of lysosomal hydrolases in mammalian cells, N-glycans have no specific function in the transport of glycoproteins into the plant vacuole. However, the presence of N-glycans, regardless of their structures, is necessary for an efficient secretion of plant glycoproteins. In the biotechnology field, transgenic plants are rapidly emerging as an important system for the production of recombinant glycoproteins intended for therapeutic purposes, which is a strong motivation to speed up research in plant glycobiology. In this regard, the potential and limits of plant cells as a factory for the production of mammalian glycoproteins will be illustrated.     

Acid lactic lactobacilli as a biotechnological toll to improve food quality and human health

The genus Lactobacillus has been widely used in food industry as starter or adjunct culture due to its probiotic features. Its biotechnological features improve the spectrum of uses of lactobacilli, which can affect its applicability directly. In this sense, this literature review gathers information and discusses the biotechnological potential of technological/probiotic lactobacilli aiming to improve food quality and human health. The primary and secondary metabolism generates specific substances, such as organic acids, carbon dioxide, hydrogen peroxide, diacetyl, fatty acids, and bacteriocins, which are determinant due to their probiotic potential, antimicrobial activity, and the development of new food flavors. In order to become industrially and commercially attractive, it is necessary develop a large-scale process with lower production costs.     

Tomato cystatin SlCYS8 as a stabilizing fusion partner for human serpin expression in plants

Studies have reported the usefulness of fusion proteins to bolster recombinant protein yields in plants. Here, we assess the potential of tomato SlCYS8, a Cys protease inhibitor of the cystatin protein superfamily, as a stabilizing fusion partner for human alpha‐1‐antichymotrypsin (α1ACT) targeted to the plant cell secretory pathway. Using the model expression platform Nicotiana benthamiana, we show that the cystatin imparts a strong stabilizing effect when expressed as a translational fusion with α1ACT, allowing impressive accumulation yields of over 2 mg/g of fresh weight tissue for the human serpin, a 25‐fold improvement on the yield of α1ACT expressed alone. Natural and synthetic peptide linkers inserted between SlCYS8 and α1ACT have differential effects on protease inhibitory potency of the two protein partners in vitro. They also have a differential impact on the yield of α1ACT, dependent on the extent to which the hybrid protein may remain intact in the plant cell environment. The stabilizing effect of SlCYS8 does not involve Cys protease inhibition and can be partly reproduced in the cytosol, where peptide linkers are less susceptible to degradation. The effect of SlCYS8 on α1ACT yields could be explained by: (i) an improved translation of the human protein coding sequence; and/or (ii) an overall stabilization of its tertiary structure preventing proteolytic degradation and/or polymerization. These findings suggest the potential of plant cystatins as stabilizing fusion partners for recombinant proteins in plant systems. They also underline the need for an empirical assessment of peptide linker functions in plant cell environments.     

Analytical biotechnology of recombinant peptides and proteins: II. A confirmation of the primary structure of fusion protein containing human proinsulin and optimization of its proteolysis by trypsin

The kinetics of trypsin proteolysis of the fusion protein (FP) containing human proinsulin was studied by a set of analytical micromethods. These were the microcolumn reversed-phase HPLC and the qualitative identification by MALDI-TOF mass spectrometry and amino acid sequencing. The first stage of the proteolysis was shown to be the cleavage of FP into the leader fragment and proinsulin. The subsequent splitting off ofC-peptide from proinsulin results in the formation of Arg^B31-Arg^B32-insulin. The effect of temperature on the formation of de-Thr^B30-insulin, a by-product, was also studied. The structure of FP was confirmed by the peptide mapping technique, and the leader fragment was shown to contain noN-terminal Met residue. For communication I, see [1].     

Enhancement of essential amino acid contents in crops by genetic engineering and protein design

The importance and urgency of providing humans and animals with quality proteins are reflected in the growing scientific and industrial interest in augmenting the nutritive value of the world's protein sources. Such nutritive value is determined by the protein content in 'essential amino acids', those that cannot be synthesized de novo and that must be supplied from the diet. It is the object of this review to discuss recent advances in the genetic modification of crops that aim to provide enhanced quantities of essential amino acids.     

U.S. racial and ethnic relations in the twenty-first century

The study of U.S. racial and ethnic relations is often reduced to the study of racial or ethnic relations. This article reveals the limitations of a focus on ethnicity or race, in isolation, and instead urges a new framework that brings them together. We consider three cases that have been conceptualized by the ethnicity paradigm as assimilation projects and by the race paradigm as structural racism projects, respectively: (1) African-American entrepreneurs; (2) the Mexican middle class; and (3) black immigrant deportees. We reveal the shortcomings of the ethnicity paradigm to consider race as a structural force or to acknowledge that structural racism conditions incorporation in marked ways; and the limitations of the race paradigm to take seriously group members’ agency in fostering social capital that can mediate racial inequality. Instead, we offer a unifying approach to reveals how ethnicity and race condition members’ life chances within the U.S. social structure.     

植物抗冻蛋白及抗冻性分子改良

概述了植物抗冻蛋白及其相关基因的研究现状,主要包括植物低温诱导蛋白、具有热滞活性的植物抗冻蛋白及其相关基因的分离、鉴定与表达调控,以及植物抗冻性基因工程研究动态.在此基础上,讨论了该领域研究中的主要问题、发展趋势及近期研究热点.     

Production and glycosylation of plant-made pharmaceuticals: the antibodies as a challenge

Antibodies have long been recognized for their diagnostic and therapeutic potential. The rapidly increasing number of monoclonal antibodies approved for immunotherapy has paved the way to an even greater demand for these molecules. In order to satisfy this growing demand and to increase the production capacity, alternative systems based on antibody production in transgenic organisms are being actively explored. In this paper, we focus on transgenic plants as a promising system for the scale-up and processing of plant-made pharmaceuticals. In particular, we point out the advantages and limitations induced by glycosylation of plant-made antibodies for human therapy.     

The impact of mineral nutrients in food crops on global human health

Nutrient sufficiency is the basis of good health, productive lives and longevity for everyone. Nutrient availability to people is primarily determined by the output of foods produced from agricultural systems. If agricultural systems fail to provide enough food diversity and quantity to satisfy all the nutrients essential to human life, people will suffer, societies will deteriorate and national development efforts will stagnate. Importantly, plant foods provide most of the nutrients that feed the developing world. Unfortunately, as a result of population pressures, many global food systems are not currently providing enough micronutrients to assure adequate micronutrient intakes for all people. This has resulted in an increasing prevalence of micronutrient deficiencies (e.g., iron deficiency, vitamin A deficiency, and iodine deficiency disorders) that now afflicts over three billion people globally mostly among resource-poor women, infants and children in developing countries. The consequences of micronutrient malnutrition are profound and alarming for human existence. Agricultural approaches to finding sustainable solutions to this problem are urgently needed. This review presents some ways in which plant nutritionists can contribute to preventing micronutrient malnutrition in sustainable ways.     

Extent and ecological consequences of hunting in Central African rainforests in the twenty-first century

Humans have hunted wildlife in Central Africa for millennia. Today, however, many species are being rapidly extirpated and sanctuaries for wildlife are dwindling. Almost all Central Africa''s forests are now accessible to hunters. Drastic declines of large mammals have been caused in the past 20 years by the commercial trade for meat or ivory. We review a growing body of empirical data which shows that trophic webs are significantly disrupted in the region, with knock-on effects for other ecological functions, including seed dispersal and forest regeneration. Plausible scenarios for land-use change indicate that increasing extraction pressure on Central African forests is likely to usher in new worker populations and to intensify the hunting impacts and trophic cascade disruption already in progress, unless serious efforts are made for hunting regulation. The profound ecological changes initiated by hunting will not mitigate and may even exacerbate the predicted effects of climate change for the region. We hypothesize that, in the near future, the trophic changes brought about by hunting will have a larger and more rapid impact on Central African rainforest structure and function than the direct impacts of climate change on the vegetation. Immediate hunting regulation is vital for the survival of the Central African rainforest ecosystem.     

Analytical biotechnology of recombinant peptides and proteins: I. determination of the purity, composition, and structure of human, porcine, and bovine insulins

A method for analysis of the type, purity, and possible structural modifications of insulins of bovine, porcine, and human origin was proposed. It is based on a combination of narrow-bore reversed-phase HPLC and mass spectrometry. The hydrolysis of insulins with highly specific Glu-protease V8 fromStaphylococcus aureus followed by peptide mapping of the hydrolysis products and mass spectrometry of the isolated fragments helps rapidly and reliably localize and identify substitutions of amino acid residues in insulin structure by using insulin samples of less than 1 nmol.