探討豬籠草捕蟲籠的組織結構、發育吸收與物理結構Explore the Organizational Structure, Development, Absorption and Physical Structure of Pitchers of Nepenthes
紅瓶豬籠草的捕蟲構造是由膨大後的葉柄固定在莖上,再由葉柄下凸的維管束及扁平處的維管束內縮向前端延伸發育成籠蔓,緊接著籠蔓的前端再膨大並經由細胞凋亡特化出類圓筒型、封閉的「空心葉」,最後特化出無柄腺鑲嵌在內層細胞上負責分泌、消化、吸收。無柄腺旁的原生質絲直徑較一般植物大5-10倍,幫助吸收。由於籠蓋不能閉合,下雨天時籠內物質容易傾倒,豬籠草演化出「來者不拒」的捕食策略。除了紅色食用色素和無機物以外,不管是含氮物、水溶性、酯溶性小分子皆吸收,甚至連蔗糖及大分子的澱粉、蛋白質,都以耗能的胞吞作用吸收,這與捕蠅草只吸收小分子的含氮物質及酯溶性的物質不同。而懸吊捕蟲籠的籠蔓,可以比自身重35倍的超強支撐力,維持捕蟲籠開口向上不傾倒溢出,保持較高的自然盛載量,提升捕食競爭力。
高鹽飲食對果蠅學習與記憶能力的影響及其細胞與分子機制
先前論文指出高鹽飲食會造成果蠅睡眠間斷(Jiayu Xie et al., 2019)、減短果蠅壽命(Deng-Tai Wen et al., 2020)。而另一篇論文則以小鼠作為實驗對象,發現高鹽飲食會影響小鼠記憶和學習能力(Giuseppe Faraco et al., 2018)。根據上述,高鹽飲食在不同生物中可能影響神經系統的功能,但果蠅學習與記憶能力的影響還未被探討。因此,筆者以果蠅作為模式生物,研究高鹽飲食對其學習與記憶功能是否障礙及實驗其可能的細胞與分子機制。在將野生型果蠅進行測試後,選擇了Canton-S做後續實驗,並發現餵食Canton-S 四天的高鹽食物後學習及短期記憶表現下降,而進行實驗確認是由高鹽飲食導致此障礙,再研究了一系列相關研究。 本次實驗中,首次以餵食高鹽食物對果蠅學習與記憶障礙方面進行研究,並了解到高鹽飲食也會讓果蠅產生學習與短期記憶能力障礙。目前為了找出真正的細胞與分子機制提出可使用的方法,在實驗其他可能的機制。
The influence of lanscape on nest preferences and behavior of twig nesting Hymenoptera
The occurrence and behavior of insects is significantly affected by the environment they live in. In this thesis, I dealt with the influence of structure of landscape on nesting preferences of Hymenoptera. For this comparison I had chosen to work with twig-nesting Hymenoptera, for which I have placed artificial nest opportunities into four biotopes – heath, edge of a heath, country lanes between fields and field. The studied location is located south of Znojmo near Podyjí national park. Particularly, I have focused on small carpenter bees of genus Ceratina. My results show that there is a big difference in the species distribution between the habitates of field and heath. The habitats of edge of a heath and country lanes make up a gradient between these two biotopes. The ecosystem of fields was preferred by a sphecid wasp Pemphredon lethifer and Ceratina cyanea. On the other hand, the ecosystem of heath was preferred by Ceratina chalybea, Ceratina nigrolabiata and megachille bee Hoplitis tridentata. I had also found out that in species that are more abundant on heaths, there is higher mortality of offsprings. Heaths were a place of the highest competition between species, as a result of which species with a lower body weight (Ceratina nigrolabiata) have been pushed into narrower twigs by larger species (Ceratina chalybea). I recorded a high number of nests in biparental bee Ceratina nigrolabiata, which were guarded only by mother in fields and country lane habitats. This may indicate that Ceratina nigrolabiata is only facultatively biparental, not strictly biparental as was considered until now.
Prismalla: Mist water collector
The lack of drinking water in human settlements triggers a series of problems that are linked and affect the development of humanity: health problems, lack of water security for companies, lack of jobs, insecurity, among others. We observe this problem in the communities of the municipality of Las Vigas de Ramírez, Veracruz, where there is a great problem with the water supply, although there is a high presence of mist. Faced with this situation, we undertook the task of investigating a water harvesting method that is easy to implement, operate and maintain. We investigated and analyzed the methods of mist condensation through physical barriers, finding that the polyethylene shadow mesh was the means to achieve this, because it allows the passage of the wind, it is very light, easy to manipulate and above all that it presents the phenomenon of percolation that allows water droplets of various diameters to be accommodated therein. We designed a device that allows to present a mist catchment area through a prismatic structure enabled with meshes and condensed water receivers, portable, easy to use and maintenance and very economical with a performance of 20 liters per day. To achieve our project, factors such as air humidity, dew point, wind speed and direction, height, temperatures and available spaces must be considered.
CONTACTLESS AND NON-DESTRUCTIVE DETECTION OF CHICKEN MEAT CONTAMINATION WITH LASER SPECKLE METHOD
Harmful microorganisms in food can cause deterioration of human health, poisoning and in some cases even death. Especially fresh meat and chicken products create a suitable environment for the growth of microorganisms in terms of the nutrients it contains, water activity and pH level. For this reason, detection of microorganisms in meat products is an important issue in terms of food safety and human health. In this project, it is aimed to detect live microorganisms in meat products, especially chicken meat, in a simple, non-destructive, non-contact and fast way using laser speckle method. Laser speckle images of healthy and stale chicken meat were taken, contrast parameter and correlation analysis of the obtained patterns were made. It was observed that the contrast parameter for staled chicken meat increased by approximately 3 times compared to fresh chicken. This increase provides an understanding of the difference between contaminated chicken and fresh chicken. Speckle density changes over time in relation to the movements of living microorganisms. Thus, the correlation in laser speckle density patterns taken from contaminated tissues is disrupted. In the measurements taken with photodiode, by analyzing the change of light intensity of the speckle patterns on fresh and contaminated tissues over time, the detection of microorganisms was made easier and more precisely without the need for image processing. The proposed measurement system is a new method that detects meat contamination with laser speckle imaging. It can be developed and made portable and can be used easily in homes. Since it is a simple, non-destructive and fast method, it can be used to determine the shelf life of meat in food distribution places and markets. In addition, it has the potential to be calibrated and used for other food products other than meat products. The system developed with this study is cheap and easy to use, and the laser speckle imaging method is used in a different field other than biomedical, contributing to the literature.
HOST TARGET PROTEINS OF SPIKE PROTEIN OF SARS-COV-2
Coronavirus Disease 2019 (COVID-19) is a newly emerged infectious disease caused by the new severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV-2). In less than one year, the virus has spread around the entire world, killing millions of people and disrupting travel and business worldwide. During infection, the virus uses its Spike protein to dock onto the Ace2 protein on the surface of its human host cell. Spike is 1273 amino acids long and only a short fragment of Spike (319-541) is sufficient to bind Ace2. We hypothesized that the remaining protein sequences of Spike might have functions for viral replication beyond the binding of Ace2. We have performed Split-Ubiquitin protein-protein interaction screens to isolate human proteins by their ability to bind to Spike, and we have identified Annexin2A2 and Cytochrome b as novel human protein interaction partners of Spike. Annexin2A2 is involved in both endocytosis and exocytosis, and the protein interaction with Spike might help the virus to enter and exit its host cell. The presence of the mitochondrial Cytochrome b protein inside the cytosol promotes apoptosis, and the protein interaction with Spike could speed up sapoptosis of the infected human cell. The Nub cDNA libraries that we have generated also allowed us to screen for synthetic peptides that interact with Spike. We have isolated two synthetic peptides, FL1a and FL7a, derived from the non-coding parts of human mRNAs by their ability to interact with Spike. We found that both FL1a and FL7a interact with the C-terminal half of the Spike protein. We also found that FL7a is able to block the Spike-Spike self-interaction at the C-terminal half of the Spike protein and we think that this could block the reassembly of the Spike protein in the host cell during viral reassembly. We hope that those synthetic peptides could be used as drugs due to their ability to block protein-protein interactions of Spike with human host proteins that are essential for viral replication.
Modification of silica surface with supercritical water as a tool indicating new possibilities of existing separation methods
Silica capillaries have been an integral part of the instrumentation used in many areas of analytical chemistry for decades, especially in analytical separations. In most cases, they are used without treatment, occasionally forceless chemical surface treatments are made to suppress or enhance the activity of silanol groups. The aim of this work was to disrupt the inner surface of the capillary, perfectly smooth from manufactory, so that relatively coarse and various structures would be created, and to study their influence on the separation efficiency. The uniqueness of the used solution is based on the use of special properties of water exposed to high temperatures and pressures (supercritical water), which is able to disrupt this chemically inert material because of its aggressivity. In total, over 2000 experiments were carried out in order to define conditions suitable for the formation of various types of surface structures. Due to the high amount of resulting data, our own database application was created, allowing not only to save the picture of the structure and experimental conditions information, but also to clearly sort them out and create image reports according to the specified parameters. Samples representing individual types of structures were then selected from this database and a number of silica capillaries with a configuration suitable for electromigration analyzes were prepared. The creation of a structured surface in the input part of the separation capillary enabled the separation of some classes of substances and biosamples, which cannot be analyzed on standard capillaries with a smooth surface. An example is the complete separation of two strains of Staphyllococcus aureus bacteria (MRSA and MSSA), or the use of the absorbing capabilities of a structured surface to study the interactions of these bacteria with bacteriophages. This ability was also used in the determination of Aspergillus fungus in a sample taken directly from the patient's lungs, where there was achieved a significant increase in the sensitivity of the analysis. Structured capillaries can also be used in the analysis of food samples, i.e., for the separation of β-lactoglobulins A and B in cow's milk, which belong to its main allergens.
PVA unveiled the actual role of starch in the Briggs-Rauscher reaction
The Briggs Rauscher reaction (BR reaction) is one of the famous oscillating reactions; the aqueous mixture of KIO3, H2SO4, H2O2, C3H4O4, MnSO4, and starch exhibit color change between yellow and blue-purple repeatedly. The blue-purple color formation is due to the iodine test reaction caused by inclusions of polyiodides such as I3- and I5- in the helical structure of starch. Therefore, starch has been regarded as only an indicator in the BR reaction. But our seniors have found that the oscillation did not last without starch. They hypothesized that starch’s linear helical framework is necessary to elongate the lifetime of the oscillating reaction. If this hypothesis is correct, similar BR-type oscillations must be observed when other polymers with helical structures are used instead of starch. We found the literature which reports that polyvinyl alcohol (PVA) forms a helical structure and indicates the iodine test reaction. In our research, we studied the BR reactions using PVA, with different saponification degrees and viscosities. First, we studied the correlation between the structural features of PVA and the iodine color reaction by spectroscopic approach, exhibiting that PVA with low saponification form helical structures and show the iodine color reactions, which gives red color solutions. Second, we found that additions of the helical-structured PVA to the reaction solution instead of starch induces the BR-type oscillating reactions, while PVA without helical structure induces only a few numbers of oscillations. This is the world-first example of the oscillating reaction using PVA. The oscillation that lasted for 6 minutes with 23 oscillations was almost the same as that of the general BR reaction using starch. We concluded that the polymers with helical structures are intrinsic to elongate the lifetime of the BR reaction. Furthermore, we found that the addition of K3[Fe(CN)6], which has a high redox activity, in the reaction solution with PVA drastically elongated the lifetime (50 min) and increased the numbers of the oscillations (nearly 100 times). This result suggests that the oxidation-reduction reactions by the ferricyanide ion promotes the redox process of iodine and iodide ions.