مجله زیست شناسی ایران
سال ششم شماره 11 (بهار و تابستان 1401)

Complexity is a prominent aspect of our world today that imposes requirements on national and international thinking, institutionalism and governance. Almost all areas of human life, including the economy, have been overshadowed by this phenomenon. Although the idea of changing economic paradigm is not new, the comprehensive requirements and challenges of the 21st century have transformed it from a "choice" to a "must". The occurrence of the global pandemic crisis of the Covid-19 disease is a convincing proof of this necessity which emphasizing such a change as well as introducing its origin, i.e. biological sciences and technologies. Scientific advances in biology have led to the fact that instead of depending on natural resources as raw materials, they can be reproduced with the help of biological data, molecules and systems. Now, at the beginning of the 21st century, it seems that the fusion between biological and data sciences has led to a huge and disruptive leap which put the world on the brink of a revolution in economy. In this article, the transformative aspects of biological science developments in the context of the global economy and the emergence of the bioeconomy as irreplaceable alternative of the oil economy is briefly discussed.

In this article, a 15-year experience of teaching general mathematics in the biology faculty of Tehran University is discussed. In order to point out the structural aspects used, briefly, the literature has been discussed. This article, while staying away from chronicles or telling memories, has discussed the rational framework of the proposed changes.

Early educational interventions aim to close gaps in achievement levels between children. However, early interventions do not eliminate individual differences in populations and the effects of early interventions often fade-out over time, despite changes of the mean of the population immediately following the intervention. Here, we discuss biological factors that help to better understand why early educational interventions do not eliminate achievement gaps. Children experience and respond to educational interventions differently. These stable individual differences are a consequence of biological mechanisms that support the interplay between genetic predispositions and the embedding of experience into our biology. Accordingly, we argue that it is not plausible to conceptualize the goals of educational interventions as both a shifting of the mean and a narrowing of the distribution of a particular measure of educational attainment assumed to be of utmost importance (such as a standardized test score). Instead of aiming to equalize the performance of students, the key goal of educational interventions should be to maximize potential at the individual level and consider a kaleidoscope of educational outcomes across which individuals vary. Additionally, in place of employing short-term interventions in the hope of achieving long-term gains, educational interventions need to be sustained throughout development and their long-term, rather than short-term, efficacy be evaluated. In summary, this paper highlights how biological research is valuable for driving a re-evaluation of how educational success across development can be conceptualized and thus what policy implications may be drawn.

After the Big Bang and then the formation of the earth, the necessary conditions for the emergence of living organisms on the earth were created. Over time, different species of living organisms have evolved and appeared on the planet. With the increase in the number of species, the interactions between them have also increased. Interactions between species have increased the speed of evolution and led to the coevolution of interacting species. Much of evolution is related to the coevolution of species. It has recently become clear that coevolution is much more pervasive, dynamic and widespread than previously thought. There are four central points about the coevolution of organisms: Complex organisms require coevolved interactions to survive and reproduce; Species-rich ecosystems are built on coevolved interactions; Coevolution takes different forms and produces different ecological outcomes; and Interactions coevolve as constantly changing geographic mosaics. Human activities, including fragmentation of habitats, excessive hunting and fishing, preferring one species to another, introducing non-native species into vulnerable ecosystems, etc., often disrupt the coevolutionary process by changing the nature and intensity of interspecies interactions.

Sex control is one of the most important factors in the commercialization and efficient proliferation of fish species which affects reproduction, growth and product quality. A balanced sex ratio is more important for broodstock management, as it helps to develop a suitable breeding program. However, the production of monosex populations is desirable in some species because the existence of sexual dimorphism can make one sex more valuable due to the effect on growth or first time of sexual maturation, even in color or shape. Sex in fish is influenced by genetic and environmental factors. Unlike mammals and birds, with highly conserved major genes through a specific genetic network responsible for gonad differentiation, various sex determination mechanisms have been reported in fish. Currently, six different major genes (dmY, gsdf, amhy, amhr2, sdY and sox3) reported to be involved in fish sex determination. The most common environmental factor is temperature, which affects the regulation of the expression of genes involved in gonad development. The aim of this paper was to review the genetic and environmental factors affecting fish sex along with the application of sex control in commercial species.

Nitrogen as an essential nutrient element for organisms has many different oxidation numbers. Nitrogen cycling is sum of the changes and transformations of these oxidation numbers of nitrogen. One of the important nitrogen cycling process is mineralization that has important role in soil fertility. Mineralization has two stages that accomplishes by Nitrosomonas and Nitrobacter respectively. The environmental conditions and type of nitrogen containing material affect the activity of these microorganisms and consequently affect the rate and amount of mineralization. Generally, inappropriate ventilation and anaerobic conditions, drought, salinity and soil compaction decrease the amount of mineralization. Plowing the soil and plant residual management has positive effects on mineralization. The decomposition of Organic residues degradation is related to the ratio of soil C/N. Nitrogen-rich compounds, like legumes, vegetables and weeds, and animal fertilizers that have low C/N, decompose at a higher rate, and, by decomposition, more nitrogen is released. Lignine-rich and rough residues such as palm, sugarcane bagasse, cereals and wood remnants with high C/N have a slower decomposition. The number C/N=24 is considered as an indicator in organic matter decomposition and nitrogen mineralization. If residues such as wheat straw with C/N=80 are added to the soil, the microorganisms use soil nitrogen storage to adjust their C/N and thus to supply their nitrogen, causing a shortage of nitrogen.  Conversely, if residues such as young hay with C/N=13 are added to the soil, the excess nitrogen will reach to plant. Therefore, plant residues management and crop rotation is very important. In practice, in order to prevent of nitrogen deficiency in plant, organic residues with low nitrogen contents should add nitrogen to the as soil as chemical fertilizer. In some areas, residues of previous crops are burned which reduces the storage of organic matter and soil fertility, air pollution and increase greenhouse gases. This is while these residues can have many useful uses. Due to low contents of organic matter in most of country’s soils and dry climates, it is necessary to apply of managing practices in order to maintain and increase soil organic matter.

Lactococcus lactis (L. lactis) is a gram positive bacterium from LAB bacteria (LAB) with a long history of processing and production of dairy products. The unique properties of this bacterium include rapid growth, high cell density, usable in fermentation industry, without inclusion body, surface display, endotoxin free, no external protease activity, having the least internal protease activity, and most importantly the ability of extracellular protein secretion. Therefore, it is considered to be a safe and appropriate host for the production of eukaryotic recombinant proteins in research and industry. The bacterium is, a cellular factory for production of a wide range of protein antigens as a vaccine and, a suitable host for delivery of therapeutic proteins and biologically active molecules into cells. For this purpose, several expression vectors and bacteria strains have been designed to express and produce recombinant proteins, described in this review.

The oral cavity is one of the most populated bacterial habitats. In addition to the presence of bacteria in this oral enclosure, the formation of organized biofilm structures by the bacteria faces major problems in the fight against oral bacterial infections. On the other hand, the increasing incidence of antibiotic resistance of bacteria complicates the treatment and prevention process of infections. In recent years, researchers have found much interest in finding suitable alternatives to antibiotics. Using the antibacterial potential of bacteriophages as a biological and reproducible approach whose therapeutic efficacy has been determined in fighting bacterial infections and biofilms, has provided a promised perspective in different areas of prevention and treatment of bacterial infections including oral and dental hygiene. Therefore, in this review, after briefly presenting the features and benefits of bacteriophages, the possibility of specific and commercial use of phages in hygiene products of mouth and teeth such as mouthwashes and toothpaste, as the most widely used hygiene products in the prevention of injuries caused by bacterial infections of the mouth and teeth, was explained.

Thorium is a radioactive metal and is actinide family of periodic table with a half-life of 14 billion years and approximately 99% is in the form of thorium-232 isotopes. From past to present it has been used as a contrast agent (in the form of thorotrast) in imaging, ceramic manufacturing, applications in aerospace industries and it is now considered a contributing element to the fuel cycle in nuclear facilities of some countries.Thorium emits alpha, beta and gamma rays. Therefor it is necessary to know the health implications and understand the consequences of exposure to this radioactive substance. Due to differences in the routes of entry of thorium into the body example of inhalation, mouth and skin, absorption and distribution and its effects on human and animals body are different. In this paper which begins with the introduction of thorium properties, after examining the pathways of its entry into the body, examples of its consequences for human, animals and the environment are discussed.

Colloidal gold nanoparticles have been used in some medical applications in past centuries. Using different sciences in the synthesis and evaluation of gold nanoparticles has been very useful. Nowadays, drug and nucleic acid delivery to a target tissue in body is one of the promising prospects for using gold nanoparticles. Moreover, gold nanoparticles with effective absorption properties of light have been useful in the diagnosis of the disease in addition to the treatment of cancerous tissues by means of photodynamic therapy, photothermal therapy and radiofrequency therapy. Since gold nanoparticles are one of the promising candidates for targeted delivery of drug, nucleic acid and modulator of angiogenesis process, not only its synthesis and its shape and size, but also its functionality is one of the key aspects of how it is intended and processed that properties such as its biological distribution and toxisity in the body. Furthermore, the efficacy and the immunological consequences of the compounds containing gold are highly dependent on its functionalization, and this field requires more and more efficient research. Considering the research on these nanoparticles, this article summarizes the work done on these nanoparticles.

The study of plant death is completed by defining plant cell senescence. Senescence is an inseparable part of plant growth. Like many other plant processes, this is a genetic control program that is regulated by a set of environmental and genetic factors. These factors and their mechanisms respond to the relationship between sources and sinks in which glucose signals and hormonal regulation and cellular genetics play a major role. During senescence, nutrients such as nitrogen, phosphorus, and glucose are released from the breakdown of macromolecules in leaf cells, to be assigned to growing organs or storage tissues. Symptoms of leaf senescence include chlorophyll loss, dehydration, and eventually plant death. Recognition of senescence is very necessary because with sufficient knowledge, senescence can be manipulated in the desired direction. For example, current molecular genetic approaches are used for postpone senescence, like blocking ethylene production or increasing cytokinin production. They are based on plant hormone mechanisms. Plant storage products increase their life span. In order to understand leaf senescence, many genetic SAGs, especially transcription factors and encoding components of transmission pathways, various gene functional methods are described.

Skeletal muscle is a heterogeneous tissue composed of fast and slow fibers. One of the features of skeletal muscle is the highly organized structure that provides variety of functional capabilities ofthis tissue. Muscle fibers are also able to regulate their phenotypic properties in response to different functional needs. Types of muscle fibers can be identified by differences in their structural and functional properties. The main difference between muscle fibers is related to the contractile fibers of actin and myosin. Actin is involved in important cellular processes, including muscle contraction. Myosin is a molecular engine that converts the chemical energy released by ATP into mechanical energy. Energy production in myosin occurs through a number of ATPase in the myosin heavy chain. The myosin heavy chain isoform determines the maximum velocity and shortening force with respect to the cross-sectional area of each muscle fiber. Differences in energy costs and ATP phosphorylation potentials in different types of fast and slow fibers can be effective in the exchange of MHC isoforms. It seems that exercise can change the MHC isoforms through various mechanisms and consequently change the muscle fiber phenotype. In this review, we persent the potential effect of exercise on MHC isoforms.

Epilepsy is a chronic noncommunicable disease of the brain that affects around 70 million people worldwide. It is characterized by recurrent seizures, which are brief episodes of involuntary movement that may involve a part of the body (partial) or the entire body (generalized) and are sometimes accompanied by loss of consciousness and control of bowel or bladder function. Nearly 80% of people with epilepsy live in low- and middle-income countries. It is estimated that up to 70% of people living with epilepsy could live seizure- free if properly diagnosed and treated. The risk of premature death in people with epilepsy is up to three times higher than for the general population. Three quarters of people with epilepsy living in low-income countries do not get the treatment they need. In many parts of the world, people with epilepsy and their families suffer from stigma and discrimination. Due to the increasing number of epilepsy in Iran and the cultural and social problems of people with epilepsy, the need for information and culture about the reality of this disease is felt. In this article, first, while defining epilepsy and seizures, the history and importance of the disease are examined. Then, the causes of epilepsy, types of epilepsy and its social complications are introduced. Finally, epilepsy treatment methods and its epidemiology are briefly reviewed.

Tilapias are the most well-known invasive fish in the world, impacting natural ecosystems, due to their high reproductive rate, omnivorous nature and high resistance to environmental conditions, pollution and disease and become serious competitors for native species. On the other hand, these fish are relatively cheap and delicious which make them very popular among fish breeders, due to their low cost. Based on scientific research, there are concerns about the fat content of these fish. Tilapia has much less omega-3 fatty acids and more omega-6s than other fish, which can cause heart disease, cancer and other chronic problems. While many native fish and some farmed fish, such as trout, die in contaminated water, tilapia can survive and even breed in contaminated water, resulting in absorption and bioaccumulation of contaminants into the fish body, which can be transmited to humans. In general, many experts believe that the consumption and breeding of tilapias are harmful to human health and aquatic ecosystems.Therefore,, farming of tilapia in the country has no economic or environmental justification

In scientific research, the mouse has a special place and is considered as the first selective animal. Laboratory mice in biology, bacteriology, virology, pharmacology, physiology of diseases, the cell and cancer, nutrition, genetics, serum and vaccine preparation, biological products testing, pharmaceutical products testing, psychological studies, behavioral tests, anomalies testing, toxicology tests, nutritional supplements testing, space research, isotopes and radioactive materials, and many other topics are used. Since many experiments performed on laboratory mice, they need to be anesthetized for a variety of injection methods, blood collections, surgery, and so on. Therefore, the necessity of using appropriate anesthetic drugs and introducing various standard injections in this laboratory animal is necessary.

A diverse array of successful, first-generation SARS-CoV-2 vaccines have played a huge role in efforts to bring the COVID-19 pandemic under control, even though inequitable distribution still leaves many vulnerable. Additional challenges loom for the next phase. These include optimizing the immunological rationale for boosting—how often and with what—and the best approaches for building a future-proofed, durable immune repertoire to protect against oncoming viral variants, including in children. The landscape of vaccine producers and technologies is likely to become even more heterogeneous. There is a need now for appraisal of future approaches: While some favor frequent boosting with the first-generation, ancestral spike vaccines, others propose frequent readjustment using current variant sequences, polyvalent vaccines, or pan-coronavirus strategies.

The naked mole rat (Heterocephalus glaber) displays exceptional longevity, with a maximum lifespan exceeding 30 years. This is the longest reported lifespan for a rodent species and is especially striking considering the small body mass of the naked mole rat. In comparison, a similarly sized house mouse has a maximum lifespan of 4 years. In addition to their longevity, naked mole rats show an unusual resistance to cancer. Multi-year observations of large naked mole-rat colonies did not detect a single incidence of cancer. Here we identify a mechanism responsible for the naked mole rat's cancer resistance. We found that naked mole-rat fibroblasts secrete extremely high-molecular-mass hyaluronan (HA), which is over five times larger than human or mouse HA. This high-molecular-mass HA accumulates abundantly in naked mole-rat tissues owing to the decreased activity of HA-degrading enzymes and a unique sequence of hyaluronan synthase 2 (HAS2). Furthermore, the naked mole-rat cells are more sensitive to HA signaling, as they have a higher affinity to HA compared with mouse or human cells. Perturbation of the signaling pathways sufficient for malignant transformation of mouse fibroblasts fails to transform naked mole-rat cells. However, once high-molecular-mass HA is removed by either knocking down HAS2 or overexpressing the HA-degrading enzyme, HYAL2, naked mole-rat cells become susceptible to malignant transformation and readily form tumours in mice. We speculate that naked mole rats have evolved a higher concentration of HA in the skin to provide skin elasticity needed for life in underground tunnels. This trait may have then been co-opted to provide cancer resistance and longevity to this species.

Today, with the rapid growth of the population, there is an increasing need to produce productions that are useful and harmless for the health of communities and the environment, which are important in various industries such as food, clothing, paper, medicine, etc. The use of enzymes and especially xylanase plays a special role in various industries due to the specificity and speeding up of the operation, and the protection of the primary raw materials and preventing damage to them (1). Xylanase is a glycoside hydrolase, which breaks the ẞ1and 4 glycosidic bonds in the structure of xylan. Xylan is one of the most important polysaccharides involved in plant cell walls. In nature, there are different types of this enzyme, each of which has a special function for its specific substrates. Also, they are divided into mesophilic, psychrophilic, and thermophilic based on their activity at different temperatures, and this diversity has made them widely used in various industries (2).

This week marks the 10th anniversary of the first major survey of microbial diversity in the human body, published in the journal Nature by the Human Microbiome Project Society, of which I was a member. Before that, microbiologists knew that the body is a host for a large group of living organisms, including bacteria, fungi, and viruses, which are spread over the surface of the skin, mouth, and gut, collectively known as the microbiome.

In the list of scientific tools that help us understand health, evolution or the environment, the Trinidadian copyfish is not often used.

A California-based biotech company called Ultima Genomics has revealed a secret, claiming to offer a new low-cost, high-throughput sequencing program that can sequence the entire genome for $100.

The present study was conducted to introduce and review the book titled "Rotifers: Aquaculture, Ecology, Gerontology, and Ecotoxicology". This book shows the latest advances in rotifers studies in various fields, including aquaculture, ecology, gerontology, and ecotoxicology. In the book, various subjects has been studied, including speciation in the Brachionus plicatilis species complex, mass culture, enrichment of rotifers, use of rotifers for larval rearing of marine fishes, history life, use of rotifers to explore the ecological impacts of toxic substances and the role of rotifers in ecotoxicology. Due to the author's efforts to provide a complete reference of rotifers, we suggest that this book be used as a reference in universities and research institutes. The book is intended to respond the scientific needs of students and researchers in the fields of fisheries, aquaculture and ecotoxicology, due to the excellent study of various aspects of rotifers.